A multicenter, double-blind, randomized, placebo-controlled, parallel study was conducted to compare the efficacy and safety of cilostazol 100 mg and 50 mg, both administered twice daily, with that of placebo in patients with moderately severe intermittent claudication (IC) secondary to peripheral arterial disease.A total of 394 subjects 40 years of age or older with chronic, stable, symptomatic IC received cilostazol 100 mg twice daily, 50 mg twice daily, or placebo for 24 weeks. Subjects receiving cilostazol 100 mg twice daily experienced a 21% net improvement in maximal walking distance (MWD)compared with placebo subjects (p = 0.0003) and a 22% net improvement in distance walked to the onset of symptoms (PFWD) (p = 0.0015). Subjects who received cilostazol 50 mg twice daily also benefited from therapy, but not to a statistically significant degree (7% and 11% improvement in MWD and PFWD, respectively). Quality-of-life and functional status assessments corroborated these objective results. Cilostazol, in particular 100 mg twice daily, significantly improves symptoms in patients with IC.

A review of all patients diagnosed with venous thromboembolism (VTE) at an academic medical center from 1996 to 1998 revealed a wide variation in management and subsequent patient outcomes and a 30% increase in utilization of the vascular laboratory from the previous 2-year period. The purpose of this study was to determine physicians' knowledge and management strategies before the implementation of integrated care pathways for VIE. Mail surveys were sent to 650 physicians covering 3 academic medical centers. The disciplines targeted were from those physicians who had previously referred patients for any VTE screening examination. One-hundred and twenty-eight physicians (20%) completed the survey. Only 12% of the physicians were able to correctly identify all of the veins routinely imaged as either deep or superficial veins. Fifty-nine percent of the physicians incorrectly identified the superficial femoral vein of the thigh as a superficial vein, and 23% believed the popliteal vein to be a superficial vein. Only 17% of the respondents correctly classified the tibial-peroneal veins as deep veins. Approximately 70% of the physicians stated that they would not treat symptomatic isolated calf vein thrombosis, and, of those, only 42% said that they would obtain serial duplex scans to monitor for proximal propagation. Physicians underestimated the charges for all diagnostic screening tests, and only 14% were able to correctly identify the range of charges for a venous duplex scan. This survey of physicians demonstrated a lack of basic knowledge regarding lower extremity venous anatomy, charges for the different diagnostic tests used to diagnose VIE, and, most importantly, current treatment standards for VTE.

PURPOSE:The objectives of this study were to describe the venous valves and determine their fate over time in reversed saphenous vein (RSV) and in situ saphenous vein (ISV) bypass grafts with duplex ultrasonography.METHODS:Sixty-four patients contributed 50 RSV and 19 ISV infrainguinal vein grafts. Forty-two of the RSVs and 17 of the ISVs had valves or valve remnants. The grafts and valves were studied serially with duplex ultrasonography to document the location, characteristics, and changes with time. The valve leaflets visualized by means of ultrasonic duplex scanning were described as moving, frozen, remnant of a cusp, or "functioning." In addition, the presence of a valve sinus and thickening of the wall at the site were documented. Grafts were studied at 1, 2, 3, 4, 6, 9, 12, and 18 months and then annually.RESULTS:In 42 RSV grafts (84%) and 17 ISV grafts (89.5%), 200 valves were identified. Only five of the 200 valves (2.5%) required intervention because of a velocity ratio (VR) of 3.5 or greater. Eight (42.1%) of the 19 ISV grafts needed 15 revisions, and 18 (36%) of the 50 RSV grafts required 30 revisions. The five revisions for a stenotic valve occurred only in RSV grafts. From the 30 revisions in the RSV grafts, only 16.7% (5 of 30) were for a valve-related stenosis. The average follow-up period for a valve from the time of detection was 16.1 +/- 9.6 months. Ten of the 17 (58.8%) valve-associated stenoses (VR > 2.5) showed a regression to a VR less than 2.0 within a mean time of 3.1 months (range, 1.5-4.5 months). A progression of the valve-associated lesion from a VR less than 2.0 to a VR higher than 3.5 occurred in only one case within a period of 3.5 months.CONCLUSION:The described features of valves in saphenous vein grafts are common and can be identified by means of duplex sonography. Only 16.7% of the revisions in RSV grafts were performed because of a valve-related stenosis, and none of the revisions in ISV grafts were performed because of a valve lesion. Lesions associated with a valve may regress in time. No specific valve features could be identified as "high" risk for graft failure.

It is known that bruits often can be heard downstream from stenoses. They are thought to be produced by disturbed blood flow and vessel wall vibrations. Our understanding of bruits has been limited, though, to analysis of sounds heard at the level of the skin. For direct measurements from the stenosis site, we developed an ultrasonic pulse-echo multigate system using quadrature phase demodulation. The system simultaneously measures tissue displacements and blood velocities at multiple depths. This paper presents a case study of a severe stenosis in a human infrainguinal vein bypass graft. During systole, nearly sinusoidal vessel wall vibrations were detected. Solid tissue vibration amplitudes measured up to 2 microm, with temporal durations of 100 ms and frequencies of roughly 145 Hz and its harmonics. Cross-axial oscillations were also found in the lumen that correlate with the wall vibrations, suggesting coupling between wall vibration and blood velocity oscillation.

HomeCirculationVol. 102, No. suppl_4Peripheral Vascular Disease Free AccessOtherDownload EPUBAboutView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyRedditDiggEmail Jump toFree AccessOtherDownload EPUBPeripheral Vascular Disease D.E. StrandnessJr and John F. Eidt D.E. StrandnessJrD.E. StrandnessJr From the Department of Surgery (D.E.S.), University of Washington School of Medicine, Seattle, and the Division of Vascular Surgery (J.F.E.), University of Arkansas for Medical Sciences, Little Rock. and John F. EidtJohn F. Eidt From the Department of Surgery (D.E.S.), University of Washington School of Medicine, Seattle, and the Division of Vascular Surgery (J.F.E.), University of Arkansas for Medical Sciences, Little Rock. Originally published14 Nov 2000https://doi.org/10.1161/circ.102.suppl_4.IV-46Circulation. 2000;102:Iv-46–Iv-51There is little doubt that one of the greatest advances in the field of peripheral arterial disease was our ability to visualize problems wherever they occurred. This was possible because of the development of arteriography. One of the dramatic developments that made this possible was the observation by Forsmann1 in 1929 that a catheter could be threaded through a peripheral vein into the right heart. He also suggested the possibility of injecting a contrast agent through the catheter for imaging purposes. Because of this contribution, he was awarded the Nobel prize in 1953. Seldinger2 in 1953 pushed this concept even further by showing that it was possible to replace an intra-arterial needle with a catheter that could be manipulated within the arterial system.These developments, along with the realization that arteries could be replaced, led to many of the early advances. One of the first methods used to replace segments of abdominal aorta was the use of homografts. Dubost et al3 in 1952 reported the replacement of an aortic aneurysm with a homograft. This procedure was rapidly followed by similar efforts in the United States by Julian et al4 and Debakey et al.5 These homografts were initially used for the treatment of abdominal aortic aneurysms but did have serious problems related to size, according to the anatomy of the patient and late breakdown of the grafts themselves.6 Once it became obvious that arterial homografts were not an answer to the problem of arterial replacement, development of alternative methods moved ahead rapidly. Vorhees et al7 in 1952 reported the first application of an artificial prosthetic device for arterial replacement. This led to the development of other prosthetic materials such as Dacron, Teflon, and polytetrafluoroethylene.8 These grafts were and still are in widespread use for treatment of arterial problems.All of these methods, for both the exposure of diseased anatomy and its correction, were developed in this time frame and remain in place even today. In the early phases of applying grafting techniques, one of the most difficult problems was related to the management of abdominal aortic aneurysms. The landmark study of Estes9 in 1950 pointed out the lethal nature of these lesions if left untreated. Although these lesions became recognized as a cause of death, it required the surgical application of developed techniques to show that resectional therapy was beneficial. Experience over the past 50 years has clearly demonstrated an improvement in long-term survival after aneurysm resection and replacement with prosthetic grafts.10 These grafts were also developed for bypassing areas of occlusion, both in the aortoiliac area and for femoral-popliteal occlusive disease.11A parallel advancement of great importance was the use of autogenous tissue to bypass areas of occlusion. The experience in the Korean conflict showed that limb survival secondary to arterial injury could be greatly improved by use of the saphenous vein as the bypass conduit.12 The saphenous vein was not only superior in terms of long-term patency but also was not as prone to infection as prosthetic devices when placed under less-than-optimal circumstances.The use of autogenous veins for bypass grafting was applied with increasing frequency, particularly in areas distal to the inguinal ligament, where prosthetic grafts did not function as well in the long term. The concept of in situ versus reversed saphenous vein also emerged in this time frame.1314 Using veins as reversed conduits, one did not have to deal with the issue of venous valves. However, when used in the in situ position, the valves had to be disrupted to permit unimpeded arterial flow. Although argument continues regarding the superiority of reversed saphenous vein over the in situ method, it is clear that when the vein is used to bypass lesions well below the knee, the in situ method offers some advantages in terms of sizing the anastomoses.It should be noted that during this era there were also advances that at first glance did not appear to be very important, but in reality were a big influence on how these surgical procedures were successfully carried out. An obvious advance was the use of magnification in dealing with suturing blood vessels to ensure optimal coaptation. In addition, development of a variety of atraumatic vascular clamps represented a major advance. The development of monofilament vascular sutures also was a major advance in terms of ease of handling, with multiple sizes being available to fit the needs of the operative procedure at hand. Each of these technical innovations made the satisfactory performance of direct arterial surgery much simpler and better.During this rapidly developing technological era with new approaches to aneurysmal and occlusive disease, the method of patient identification depended entirely on a well-taken history, palpation of pulses, and listening for bruits. Although this was satisfactory in many respects, it did not offer the type of information that one often needed to assess the extent to which the physiology of blood flow had been either interfered with or restored to normal after an operative procedure. This lack of information led to the development of an entirely new area of study relating to the physiology of arterial blood flow and how it was affected by disease. In addition, it became important, since it was necessary to know to what extent the pathophysiology of arterial obstruction had been corrected.One of the major questions dealt with in this era was how one should study the arterial system and how this information should be used. Fortunately, a considerable amount of work was being done on the physiology of blood flow that could be applied to patient studies if methods were made available to provide this information. This required tools that could be applied to humans. The most common methods used by physiologists were plethysmographic, combined with some method of measuring intravascular pressures.1516171819 Plethysmographic techniques were applied to humans and provided information on blood flow in the limbs and how it was affected by disease. At the same time, these methods could be used to estimate systolic pressures at several sites along the length of the limb.1819 In addition, measurement of systolic pressures in the upper and lower limbs led to the concept of expressing these values as a ratio (the ankle/arm index, or AAI). It was noted that although absolute levels of pressure should be measured from both the upper arms and ankles, the level of the AAI was particularly useful in clinical practice.1718202122232425One of the early concerns about both limb pressures and blood flow measurements was that they were indirect and did not, in most cases, affect what was done to the patient. However, it became apparent that the AAI was the best single evidence available concerning the prevalence of arterial occlusive disease and its severity.262728293031 In addition, it was learned that changes in both the absolute levels of systolic pressure and the AAI could be used as markers of both improvement as well as failure of direct surgical procedures.172122 It was also noted that an increase in the AAI in patients not treated surgically was associated with improvement of the collateral circulation, whereas a decrease was associated with disease progression.2132 The practice of measuring systolic pressures was extended to the digits as well. The level of systolic pressures recorded could also be used to predict whether or not an ulcer was likely to heal.2033 Another advantage of toe pressures is that they were particularly useful in patients with diabetes, in whom medial calcification of the tibial-peroneal arteries could make the measurement of ankle systolic pressure unreliable. In fact, it is now a standard procedure to carry out pressure measurements from the toe in cases where calcification of the digital arteries has not occurred.34 These recommendations relative to the role of vascular studies in diabetic patients was arrived at by a consensus conference sponsored by the American Heart Association (AHA), with the results published in Circulation.34A major advance with regard to the study of arterial disease occurred when it was recognized that ultrasound could be transmitted through the skin. It was possible to obtain information concerning arterial blood flow patterns in health and disease by taking advantage of the Doppler effect.3536 The earliest devices depended entirely on an audible interpretation by the observer of the backscattered, Doppler-shifted ultrasonic signal.2537 The subjective nature of interpretation of the audible velocity signal limited its application to some degree. However, with audible output alone, the Doppler device became the most commonly used method to measure systolic pressures from the arm and ankle.2122 Another problem was that proper use of the method depended on the skill of the examiner, who had to understand arterial anatomy as well as the significance of flow patterns that were observed in both health and disease. Nonetheless, despite the shortcomings of this method, these devices are in widespread use throughout the world for studying arterial flow patterns and the measurement of upper- and lower-limb systolic pressures.As the field of ultrasound technology progressed, it became apparent that it would be possible to combine ultrasonic B-mode imaging with a pulsed-Doppler device for the study of peripheral arteries.3839 There were several technical innovations that made this possible and that incorporated the pulsed Doppler, thus allowing selective sampling of blood flow40 at any point along the transmitted sound beam. In addition, development of the fast Fourier transform spectrum analyzer for depiction of both the frequency and amplitude of the backscattered Doppler signal was extremely important.41As technology improved and as we began to appreciate the medical need for a real-time combined imaging and Doppler system, it was apparent that this method could be extended beyond the carotid artery to the arteries of the limbs, the visceral vessels, and finally, to the intracranial arteries themselves.414243444546 As a result of these developments, there were no arteries in the body that could not be accessed for study. With this new technology, it became possible to screen patients suspected of having disease, to document its severity, and to use the same methods to document the results of therapy. The technique has proved useful for follow-up of arteriosclerotic disease of the carotid and renal arteries as well as for patients who have undergone peripheral arterial grafting procedures.434748495051Although this new technology has greatly improved how we evaluate patients, it has also had a remarkable effect on medical practice. This is most evident in the case of carotid artery atherosclerosis, for which duplex ultrasound scanning is now being used as the sole diagnostic test before carotid endarterectomy.5253 This is now possible in up to 90% of patients, resulting in marked savings to the healthcare system and removing the patient from the risk of having a neurological event during the arteriogram. This risk has been estimated to be between 1% and 2%.54What are the areas where this new technology has had a major impact? These include the carotid artery, the abdominal aorta and iliac arteries, and the arteries distal to the inguinal ligament. In addition, it is now possible to document the status of the renal arteries for the presence of atherosclerosis and fibromuscular hyperplasia, which are common causes for the development of hypertension.44 This same method has been shown to be useful for the follow-up of disease and therapy for all of the above-mentioned areas.4748How do these diagnostic methods impact the field of peripheral arterial disease and its management? The AHA has played a prominent role in bringing this information to the medical public. An example of their input can be read in the AHA Medical/Scientific Statement entitled Diagnosis and Treatment of Chronic Arterial Insufficiency of the Lower Extremities: a Critical Review.55 This document reviewed the current status of the field, with particular emphasis on which areas had level 1 evidence to support efforts currently used. This document represents a fair summary of the progress that has been made in the past 50 years, as well as suggestions where further work needs to be done.In line with the scientific statement, there has been increasing interest in developing level 1 evidence for our approaches to the diagnosis and treatment of arterial vascular disease. One area where this plan has succeeded is in relation to the role of carotid endarterectomy in stroke prevention. Before 1913, stroke was believed to be secondary to intracranial vascular pathology. In that year, Ramsey Hunt56 suggested that occlusions of the cervical arteries were important in the causation of stroke. However, there is no doubt that it was the contributions of C. Miller Fisher5758 who clearly detailed the role of the extracranial arteries in the pathogenesis of stroke. To approach this area from a surgical standpoint, Eastcott et al59 in London and DeBakey60 in the United States first reported the use of a new operation, carotid endarterectomy. Surgical interest in this area grew rapidly, but concerns were raised about the safety of the procedure and the lack of proof of its efficacy.6162 These concerns became serious enough to warrant the initiation of randomized, clinical trials to compare the procedure with conventional medical therapy.63 Large, randomized trials were undertaken to examine this issue in patients with and without symptoms There were two large trials in symptomatic patients and one in patients who were free of symptoms. These were the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the European Carotid Surgery Trial (ECST).646566 Both of these trials proved without question that carotid endarterectomy was better than conventional medical therapy for the prevention of stroke. Level 1 evidence is now in with regard to this issue. The large National Institutes of Health–supported trial of Asymptomatic Carotid Surgery (ACAS) was also a randomized trial and showed a benefit from carotid endarterectomy in selected patients.54 This is also level 1 evidence, but the results are more controversial than those in the NASCET and ECST trials.With introduction of the balloon catheter by Fogarty et al67 in 1963, the potential for transluminal treatment of arterial embolization and thrombosis was introduced. Instead of the standard methods of replacement or bypass grafting, the opportunity to restore patency by transluminal dilatation methods was brought to our attention by Dotter and Judkins68 in 1964. The "Dotter" technique of enlarging the site of arterial narrowing was improved by introduction of the balloon catheter by Gruentzig and his colleagues69 in 1974. It appeared to work, with the creation of a local dissection followed by remodeling.70 The best results were obtained with disease of the common iliac arteries, but the results were, in general, disappointing in arteries distal to the inguinal ligament.7172 Use of balloon angioplasty alone has been modified by the addition of a stent to hold the dilated segment in place, thereby preventing "rebound" stenosis.73 There has been an increasing number of intra-arterial stents developed for use in every area where atherosclerotic narrowing and occlusion develop. This field is moving very quickly, but its final use in areas such as the carotid arteries, renal arteries, and lower-extremity arteries, remains to be determined.Another area of treatment that is emerging is endovascular therapy of abdominal aortic aneurysms.74 This form of therapy appears to be safer for the patient who may pose a serious risk for open repair, but long-term results will need to be determined before this method finds a permanent place in our therapy for this very important problem.There is little doubt that one of the major problems facing all forms of intervention in the arterial system is that of neointimal hyperplasia. This represents the single most important problem influencing the long-term results of interventional procedures.7375 There have been extensive efforts to control this process, but none have proved successful in preventing this from occurring.One of the most important developments in our understanding of peripheral arterial atherosclerosis was the devastating impact of cigarette smoking.76 In addition, diabetes was recognized as a major contributing factor to the development of severe peripheral arterial disease. A fact that is poorly understood is that the distribution of atherosclerosis is different for the diabetic and nondiabetic. This is also important from a clinical standpoint.777879 It is also known that the presence of peripheral arterial atherosclerosis is a powerful predictor of cardiovascular mortality.80 In this regard, the finding of an abnormal AAI is an important marker of atherosclerosis in other arterial beds.81There also appears to be a relationship between the surface changes of the atherosclerotic plaque and the development of thrombosis.82 Development of a thrombus on the surface of a plaque may lead to total occlusion and/or the release of embolic material from that site. It is not surprising that many antithrombotic strategies have been proposed and implemented. One of the earliest strategies of immense importance was the development and use of heparin.838485 This has its greatest application for therapy during the acute event period or during interventional procedures. For long-term therapy, coumarin remains the most commonly used agent for both arterial and venous problems. It is also clear that antiplatelet agents are of great importance in the prevention of primary and secondary cardiovascular events.86 Newer and more powerful antiplatelet agents are appearing that may be even more useful, particularly during interventional procedures. In addition, the availability of low-molecular-weight heparin is beginning to change our therapeutic approach to both arterial and venous disease.87As with other areas of arterial circulation, prevention of atherosclerosis would remove the need for both expensive and potentially dangerous forms of therapy. In this regard, it is hoped that basic research in the pathogenesis of diabetes—both types 1 and 2, with their profound influence on the arterial system—will provide some understanding of this very complex disorder. Although we understand the implications of the disease and its effects on arterial circulation, it is unfortunate that we have not been able to definitively reduce the incidence of vascular complications in any of the major arterial beds.There is and hopefully will continue to be research into the pharmacotherapy of intermittent claudication. There is some hope in this regard, as evidenced by the approval of cilostazol by the US Food and Drug Administration for the treatment of stable intermittent claudication.88 It is also hoped that work will continue into the role of gene-based therapy to improve collateral circulation to the limbs.Although there have been dramatic improvements in the application of endovascular therapy for the treatment of occlusive arterial disease, its ultimate impact remains to be determined. Whereas some devices may shorten time in the hospital, the cost of follow-up studies and management of long-term complications remain to be sorted out. At the moment, it appears that most of these methods do not provide any substantial savings, either in the short or long term. Randomized trials, whenever possible, should be used to validate these new therapies. One area that stands out as both contentious and difficult is the issue of carotid stents. Successful completion of the randomized trials of endarterectomy versus conventional medical therapy has shown that the operation can be done at low risk, yet there remains the possibility that carotid stents may do as well, if not better. Unfortunately, the risk of arteriography is nearly equal to the risk of endarterectomy, and this will have to be factored into the role of this new therapy. A good cost analysis of these two approaches must be done.There is universal agreement that the response of the arterial wall to injury remains a real challenge to the future. If this process can be either prevented or controlled, the long-term results of therapy will be greatly improved, be it surgery or endovascular means. Unfortunately, to date, none of the proposed methods have been successful. It is the opinion of these authors that the peripheral arterial circulation is an ideal site for these studies to be done. Routine and regular surveillance is possible for the entire limb and can provide quantifiable evidence of the response to injury and how it is being modified. The areas where research needs to be done are with angioplasty, with or without stents, and the use of venous bypass grafts, both of which are easily studied by ultrasonic methods.4989 Work on 3D ultrasonic imaging that can quantify both the sites of restenosis, as well as monitor changes over time, will permit a realistic look at this problem. While it is clear that thrombolysis is useful for therapy of acute embolic events, its role in the therapy of chronic, occlusive arterial disease remains an important issue.909192During this period of arterial bypass grafting for the treatment of arterial occlusive disease, the search for the satisfactory small-bore arterial prosthesis has been very disappointing. It is generally agreed that there have been no developments with prosthetic materials that have matched those achieved by venous grafts.FootnotesCorrespondence to D. Eugene Strandness, MD, University of Washington School of Medicine, 1959 NE Pacific St, Box 356410, Seattle, WA 98195-6410. References 1 Forsmann W. Die Sondierung des rechten Herzens. Herzens Klin Wochenschr.1929; 8:2085–2087.CrossrefGoogle Scholar2 Seldinger SI. Catheter replacement of the needle in percutaneous arteriography: a new technique. Acta Radiol.1953; 39:368–376.CrossrefMedlineGoogle Scholar3 Dubost C, Allary M, Oeconomous N. Resection of an aneurysm of the abdominal aorta. Arch Surg.1952; 64:405–408.CrossrefGoogle Scholar4 Julian OC, Grove W, Dye WS, et al. Direct surgery of arteriosclerosis: resection of abdominal aorta with homologous aortic graft replacement. Ann Surg.1953; 138:387–403.CrossrefMedlineGoogle Scholar5 DeBakey ME, Creech O, Cooley DA. Occlusive disease of the aorta and its treatment by resection and homograft replacement. Ann Surg.1954; 140:290–310.CrossrefMedlineGoogle Scholar6 Szilagyi DE, McDonald DA, Smith RF, et al. Biologic fate of human arterial homografts. Arch Surg.1957; 75:506–529.CrossrefGoogle Scholar7 Vorhees AB, Jaretski A, Blakemore AH. The use of tubes constructed from Vinyon "N" cloth in bridging arterial defects. Ann Surg.1952; 135:332–336.CrossrefMedlineGoogle Scholar8 Deterling RA, Bhonslay SB. An evaluation of synthetic materials and fabrics suitable for blood vessel replacement. Surgery.1955; 38:71–76.MedlineGoogle Scholar9 Estes JE Jr. Abdominal aortic aneurysm: a study of 102 cases. Circulation.1950; 2:258–264.CrossrefMedlineGoogle Scholar10 Szilagyi DE, Smith RF, DeRusso FJ, et al. Contribution of abdominal aortic aneurysmectomy to prolongation of life. Ann Surg.1966; 164:678–699.CrossrefMedlineGoogle Scholar11 DeBakey ME, Crawford ES, Cooley DE, et al. Surgical considerations of occlusive disease of the abdominal aorta and iliac and femoral arteries: analysis of 803 cases. Ann Surg.1958; 148:306–324.CrossrefMedlineGoogle Scholar12 Hughes CW. Arterial repair during the Korean war. Ann Surg.1958; 147:555–561.MedlineGoogle Scholar13 Kunlin J. Le traiterment del'arterite obliterans par la griffe veinuse. Arch Mal Couer.1949; 42:371–372.Google Scholar14 Linton RR, Darling RC. Autogenous saphenous vein bypass grafts in femoropopliteal occlusive disease: a reappraisal. Surgery.1967; 61:31–40.MedlineGoogle Scholar15 Whitney RJ. 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Study of flow patterns in peripheral arteries by ultrasonics. J Acoust Soc Jpn.1959; 15:151–158.Google Scholar36 Rushmer RF, Baker DW, Stegall HF. Transcutaneous Doppler flow detection as a nondestructive technique. J Appl Physiol.1966; 21:554–566.CrossrefMedlineGoogle Scholar37 Strandness DE Jr, Schultz RA, Sumner DS, et al. Ultrasonic flow detection: a useful technique in the evaluation of peripheral vascular disease. Am J Surg.1967; 113:311–320.CrossrefMedlineGoogle Scholar38 Barber FE, Baker DW, Nation AWC, et al. Ultrasonic duplex echo Doppler scanner. IEEE Trans Biomed Eng.1974; 21:109–113.CrossrefMedlineGoogle Scholar39 Barber FE, Baker DW, Nation AC, et al. Ultrasonic duplex echo-Doppler scanner. IEEE Trans Biomed Eng..1974; 21:109–113.CrossrefMedlineGoogle Scholar40 Baker DW. Pulsed ultrasonic Doppler blood flow sensing. IEEE Trans Biomed Eng.1970; 17:170–185.Google Scholar41 Phillips DJ, Powers JE, Eyer MK, et al. Detection of peripheral vascular disease using duplex scanner III. Ultrasound Med Biol.1980; 6:205–218.CrossrefMedlineGoo

Carotid artery stenosis is an important risk factor for stroke. The European Carotid Surgery Trial (ECST) and the North American Symptomatic Carotid Endarterectomy Trial (NASCET) have demonstrated that the risk of stroke is reduced by surgery in patients with high grade stenosis (70-99%). However, because the two trials used different methods to measure stenosis, the results are not comparable and the level of stenosis which is associated with increased risk of stroke cannot be strictly defined. The benefit of surgery in asymptomatic patients is more controversial. Some studies indicate that surgery reduces the risk of stroke only in patients with ?80% stenosis and others have shown benefits for patients with ?60% stenosis. Overall, the benefits of surgery in asymptomatic patients are more difficult to define. Carotid lesion morphology also plays an important role in determining the risk of stroke; plaques which are ulcerated and echolucent are associated with a higher risk of stroke. Arteriography has been long regarded as the gold standard diagnostic tool for carotid stenosis. It is a costly and invasive technique with potentially serious complications. The results of arteriography have not been standardised which makes comparison of results from different laboratories difficult. Duplex ultrasound is inexpensive, non-invasive and can provide functional and anatomical information about vessel stenosis and plaque morphology. The use of echo-enhancing agents helps to reduce operator variability, improves ultrasound images and can help to distinguish between pseudo and true occlusions, to identify patients who will benefit most from surgery. The echo-enhancing agent Levovist(R) is safe, produces consistent results and can enhance images throughout the blood pool. Clinical studies with Levovist(R) have shown it to be safe and highly effective in improving diagnostic confidence in patients with carotid artery stenosis. The number of non-diagnostic scans is reduced markedly when Levovist(R) is used to enhance ultrasound images.

Background —Cilostazol is a new phosphodiesterase inhibitor that suppresses platelet aggregation and also acts as a direct arterial vasodilator. This prospective, randomized, placebo-controlled, parallel-group clinical trial evaluated the efficacy of cilostazol for treatment of stable, moderately severe intermittent claudication. Methods and Results —Study inclusion criteria included age ≥40 years, initial claudication distance (ICD) on treadmill (12.5% incline, 3.2 km/h) between 30 and 200 m, and confirmation of diagnosis of chronic lower-extremity arterial occlusive disease. After stabilization and single-blind placebo lead-in, 81 subjects (62 male, 19 female) from 3 centers were randomized unequally (2:1) to 12 weeks of treatment with cilostazol 100 mg PO BID or placebo. Primary outcome measures included ICD and maximum distance walked (absolute claudication distance, or ACD). Secondary outcome measures included ankle pressures, subjective assessments of benefit by patients and physicians, and safety. Treatment and control groups were similar with respect to age, severity of symptoms, ankle pressures, and smoking status. Statistical analyses used intention-to-treat analyses for each of 77 subjects who had ≥1 treadmill test after initiation of therapy. Comparisons between groups were based on logarithms of ratios of ICD and ACD changes from baseline using ANOVA test at last treatment visit. The estimated treatment effect showed a 35% increase in ICD ( P <0.01) and a 41% increase in ACD ( P <0.01). There was no significant change in resting or postexercise ankle/brachial indexes. Patients’ and physicians’ subjective assessments corroborated the measured improvements in walking performance observed in the cilostazol-treated group. Conclusions —Cilostazol improved walking distances, significantly increasing ICD and ACD. The data suggest cilostazol is safe and well tolerated for the treatment of intermittent claudication.

Band of brothers: Creators of modern vascular surgery W. Andrew Dale; 1996; 511 pages. I first met Andrew Dale in 1959 when I was a second-year resident in General Surgery. He came to Seattle to speak to the Seattle Surgical Society as a guest of J. Thomas Payne, who was then Chief of Surgery at the Veterans Administration Hospital. I had a discussion with him about the emerging field of “Vascular Surgery.” I was very impressed with his obvious enthusiasm for this type of surgery. It was apparent to me that he was a disciple of detail and the need to do things right. In 1970 he held one of the first multidisciplinary meetings on arterial occlusive disease that I was privileged to attend. It is ironic that he was among the first in my view to invite an outsider such as Charles Dotter to talk about his new procedure. Perhaps he saw something that many others missed. Dr. Dale was an elegant spokesman for Vascular Surgery and remained one of the leaders in this field up until the end of his life. He was truly a Southern gentleman. He like many in his book was in the right place at the right time. He worked hard at his profession and he was very successful. Why then would someone in the twilight of their surgical career, and in his case his life, undertake such a unique effort? The title of the book says a lot about why he decided to do this. The title comes from Shakespeare's Henry V. In that play, the English king speaking before the Battle of Agincourt proclaims, “We few, we happy few, we band of brothers; For he today who sheds his blood with me Shall be my brother.” As Dr. Dale noted, Admiral Horatio Nelson also used the term “Band of Brothers” to refer to those captains who fought with him in the Battle of the Nile. Ernest K. Gann, the famed pilot and author, also used the words to describe the group of diverse characters who were joined together by common aspirations and goals. Dr. Dale chose to interview some of the outstanding surgeons of the day who made major contributions to the field of Vascular Surgery. The choices were his, and he admitted to leaving some people out of the narration who others might think should have been included. This fact is acknowledged by both Dr. Dale and Drs. George Johnson and James DeWeese, who completed the task after Dr. Dale's death from leukemia in 1990. The names of those interviewed are well known to all of us. Their status as leaders in this field is not in doubt. However, it must be remembered that this is not a history of Vascular Surgery. It is a fascinating compilation of what went into molding the lives and careers of many of our leaders in vascular surgery. His Band of Brothers consisted of 37 surgeons. For every book review and reviewer it is necessary to point out the strengths, as well as the weaknesses of such an effort. In dealing with the latter first, this is not a historical treatise, such as John Fulton's Life of Harvey Cushing, which is a classic medical history of someone who made monumental contributions to the field of Neurosurgery. Reading this book will not provide the reader with such treatment. It is a series of self-portraits, with all the problems that such dialogue provides. It is also important to realize that this work will be of little interest to those who do not know the surgeons who were interviewed. What then is the value of this effort? For me and I am sure for all who knew these surgeons, either up close or at a distance, will be fascinated by their tales and how and why they ended up where they did and some still are. The tales are full of examples (we used to call heroes) of individuals who helped these surgeons along their way. All who were interviewed were generous, in my view, in giving credit where credit was due. In some cases the views expressed were not particularly kind to some individuals. However, I was impressed by the candor of some of the interviewees. Where will an effort such as this pay off? One of the missing elements in medicine today is a lack of interest in our historical record. My first chief, Dr. Henry Harkins, made sure that both the students and the residents appreciated those who preceded us. If we are fortunate enough to have someone, at some time, want to write a definitive history of this era, there is a lot of useful biographical information here to call on.

BACKGROUND & AIMS:Three-dimensional (3D) ultrasound imaging of the total stomach volume has not yet been achieved. The aim of this study was to investigate whether a magnetic position sensor system for acquisition of 3D ultrasonograms could be used to determine gastric emptying rates and intragastric distribution.METHODS:A system for position and orientation measurement was interfaced to an ultrasound scanner. In vitro accuracy was evaluated by scanning a porcine stomach. Fourteen volunteers, with a median age of 35 years, were scanned fasting and postcibally by two-dimensional (2D) and 3D ultrasound after ingesting a 500-mL soup meal.RESULTS:This 3D system yielded a strong correlation (r = 0.997) between true and estimated volumes in vitro. The limits of agreement were -9.1:70.1 mL in the volume range 1200-1900 mL. The intersubject variability of the total gastric volumes ranged from 12.5% to 46.0%, less than for antral area variability. The average half-emptying time was 22.1 +/- 3.8 minutes. Intragastric distribution of the meal, expressed as proximal distal volume, varied on average from 3.6 +/- 2.1 (5 minutes postpradially) to 2.7 +/- 1.9 (30 minutes postprandially).CONCLUSIONS:This 3D ultrasound system using magnetic scanhead tracking showed excellent in vitro accuracy, calculated gastric emptying rates more precisely than by 2D ultrasound, and enabled estimation of intragastric distribution of a soup meal.

BACKGROUND:Chlamydia pneumoniae has been demonstrated in atherosclerotic lesions of coronary arteries and aorta. A seroepidemiological study found C pneumoniae-specific antibody more frequently in persons with significant carotid artery wall thickening than in matched control subjects.METHODS AND RESULTS:Fresh-frozen or formalin-fixed tissue obtained at carotid endarterectomy was examined by immunocytochemistry (ICC) and the polymerase chain reaction (PCR) for the presence of C pneumoniae. Five of five fresh-frozen and formalin-fixed carotid endarterectomy specimens were positive for C pneumoniae by ICC (three of five by PCR). A total of 56 archival formalin-fixed, paraffin-embedded carotid endarterectomy tissues from three hospitals were examined by ICC. Thirty-two were positive. Thirteen normal carotid artery tissue sections from six patients were negative for C pneumoniae.CONCLUSIONS:C pneumoniae organisms are frequently found in the advanced carotid atherosclerotic lesions of persons undergoing endarterectomy. Although these findings do not establish causality for C pneumoniae in carotid artery atherosclerosis, they should stimulate investigation of a possible causal or pathogenic role for the organism in the disease.

We developed a theoretic model of arterial stenosis to study the relationship between perfusion pressure and regional hemodynamics in stenotic infrainguinal vein grafts in an attempt to identify grafts at high risk for failure. Our model was based on the concept of energy and mass conservation of the flowing blood. We used the modified Bernoulli equation (DELTAP = 4DELTAV2) to calculate the maximum possible intrastenotic peak systolic velocity (PSV) from the systolic blood pressure. PSV was measured by means of duplex ultrasonography in infrainguinal bypasses up to the time of revision (nine grafts) or spontaneous thrombosis (two grafts). We related arm systolic blood pressure, intrastenotic PSV, and prestenotic PSV obtained from duplex examinations conducted prior to graft thrombosis or revision and applied our model to these stenotic vein grafts. Intrastenotic PSV was consistently lower than maximum PSV predicted from the Bernoulli equation. The highest measured intrastenotic PSV of 600 cm/sec would require a minimum perfusion pressure of 144 mm Hg. The lowest measured PSV (20 cm/sec) was considered the minimum ''thrombotic threshold velocity.'' This model predicts that for parabolic profile flow in an 80% diameter-reducing axisymmetric stenosis (96% cross-sectional area reduction), a prestenotic PSV of 20 cm/sec would produce an intrastenotic PSV of 500 cm/sec requiring the equivalent potential energy of 100 mm Hg systolic blood pressure. Our theory implies that in patients with nocturnal hypotension thrombosis of stenotic vein grafts may occur.

Objectifs: A part l'Etude Europeenne de Chirurgie Carotidienne, les etudes recentes sur l'endartectomie carotidienne utilise la partie cervicale distale de l'artere carotidienne comme reference pour le calcul angiographique des stenoses de la carotide interne. Cependant, les sites de reference et les categories de stenoses des etudes comparant les donnees du mode duplex a celles de l'angiographie ne sont pas appliquables aux plus recentes des etudes sur endartectomie. Face a cette difficulte et au vu des resultats preliminaires de l'etude nord-americaine (North American Symptomatic Carotid Endarterectomy Trial-NASCET), nous avons prealablement analyse les resultats de l'angiographie et du duplex prenant l'hypothese que lorsque la vitesse systolique maximale dans l'artere carotide interne est ≥4 fois celle de la carotide commune la stenose de la carotide interne est ≥70-99 p. cent en prenant la partie distale de la carotide cervicale comme reference. Methodes: Dans une etude prospective au sein de quatre laboratoires universitaires associes nous avons mesure en mode duplex le rapport des vitesses systoliques maximales de la carotide interne et commune pour determiner, selon notre hypothese, les stenoses ≥70-99 % a l'insu des resultats angiographiques. Resultats: Sur la base des resultats angiographiques, la sensibilite d'un rapport de ≥4,0 pour detecter les stenoses de la carotide interne est de 90 p. cent, la valeur predictive positive de 86 p. cent, la valeur predictive negative de 94 p. cent et la precision de 90 p. cent. Conclusions: Si l'on prend la partie cervicale distale de l'artere carotide interne comme reference pour mesurer la stenose angiographique de l'artere carotide interne, une valeur du rapport de la vitesse systolique maximale de la carotide interne et commune obtenu en mode duplex ≥4,0 est un bon critere de prediction d'une stenose de ≥70-99 p. cent

The relationship between the measured arm-ankle pressure difference (AAPD), or the ankle/arm index (AAI), and the focal peak systolic velocity (PSV) at stenotic sites of infrainguinal vein grafts has not been determined. We attempted to relate these two parameters. We used Doppler systolic pressures and duplex ultrasonography to study 35 infrainguinal vein bypass grafts followed in a surveillance protocol. The following graft groups were identified: grafts in nondiabetic patients (n = 26), grafts in diabetic patients (n = 9), nonrevised stenotic grafts (n = 14), revised stenotic grafts (n = 14), and normal grafts (n = 7). AAPD and AAI were measured in both lower extremities. Pressure gradients across graft stenoses were indirectly estimated using the modified Bernoulli equation (delta P =4V2). Measured AAPDs and estimated pressure gradients showed moderate correlation in nondiabetic (r = 0.58) and diabetic (r = 0.63) patients. Correlation was fair (r = 0.3) prior to graft revision. There was no correlation (r = 0.1) in the nonrevised stenotic grafts. For individual patients with stenotic grafts who were followed in consecutive visits, the correlation varied from none to good (r range 0.01 to 0.71). We conclude that there is a lack of consistent correlation between the measured AAPD, or AAI, and the estimated stenotic graft pressure gradient. This finding illustrates the limitation of the AAI as a monitoring test to predict failure of stenotic infrainguinal vein grafts.

Based on the differences between tissue impedances in atherosclerotic plaques and on the scattering of ultrasound from blood, colors were assigned to the echo strength scale, replacing the usual gray scale in 2-D B-mode ultrasound images. Using a "green tag" indicating -55 dB to mark blood, other echo strength values from atherosclerotic plaque were assigned specific colors, creating a B-mode color ultrasound display that highlights selected echogenicities. The color scale permits the use of a wider dynamic range in the B-mode image, and allows the instrument gains to be set reproducibly.

Atherosclerotic plaques: Advances in imaging for sequential quantitative evaluation Robert W. Wissler, New York, 1991, Plenum Publishing Company, 309 pages, $150. This book is a summary of the presentations given at the North Atlantic Treaty Organization Advanced Research Workshop held in Siena, Italy, in June 1990. The central theme and one of great importance to those in atherosclerosis research is that interest is finally being shown in the lesions that lead to clinical events. Most past research has been devoted to animal models designed to define in scientific terms those factors leading to the development of the mature lesion. The human plaque has been substantially ignored, as everyone familiar with the field is well aware. The lesions themselves were rarely studied in depth probably because they all seemed so similar. Several new observations have changed this situation. The single observation that seems to be the most important is that not all lesions are the same, with some portending a serious outcome whereas others of similar size cause little harm. What are the differences and how can they be recognized? The major risk factor leading to a poor outcome may be related to the thickness of the fibrous cap and what lies beneath it. Once this cap is disrupted, several events may occur, including thrombosis with or without associated embolization. This volume reviews all of the currently available imaging methods ranging from arteriography and ultrasonography to magnetic resonance imaging. In addition some of the newer and experimental methods are also reviewed and include ultrafast computed tomography, synchrotron angiography, PET, SPECT and a variety of labeling methods. The advantages, disadvantages, and potential application of the methods are covered in detail. The most valuable aspects of this book are extensive discussions that follow each section. Important questions are asked of each participant, and their responses are enlightening and most helpful to those not completely conversant with the topic under discussion. This conference and the topics covered are extremely important to those interested in the clinical aspects of atherosclerosis and plaque development. This book is highly recommended to those interested in atherosclerosis and its detection, quantification, and relevance to the development of clinical events.

The location and extent of thrombosis in the deep venous system will determine immediate and long-term outcome. During the past 3 years, we have studied by duplex scanning 833 patients with suspected deep vein thrombosis. In this group, 209 patients (25%) had a positive study. The findings relative to location and extent of involvement are as follows. (1) The right leg was involved in 35% of patients, the left leg in 48%. Bilateral involvement was noted in 17%. (2) The veins most frequently affected by deep vein thrombosis were as follows: superficial femoral in 74%, popliteal in 73%, common femoral in 58%, posterior tibial in 40%, deep femoral in 29%, greater saphenous in 19%, and the inferior vena cava in 2%; multisegment involvement was common. (3) Total occlusion was present in 82% of the patients with deep vein thrombosis, and partial occlusion in 18%. (4) Isolated occlusion of single veins was uncommon. (5) The proximal (above-knee) area was involved in 95% of the cases with deep vein thrombosis, and the calf in 40% of the cases. Isolated calf deep vein thrombosis was found in 6% of the cases with right leg involvement and in 3% for the left. (6) Total leg involvement (iliocaval, femoropopliteal, and calf) occurred in 10% of the patients. Our data confirm the fallibility of the clinical diagnosis of deep vein thrombosis. The frequent involvement of both limbs stresses the importance of not examining just the symptomatic limb. Proximal venous thrombosis (popliteal to inferior vena cava) is much more common than isolated calf vein thrombosis as a cause for symptoms and the referral for study.

Cardiac and vascular ultrasound systems incorporting colorized gray-scale display options to supplement the standard B-mode gray-scale image have recently reappeared on the market from several manufacturers. As yet, the clinical benefit of this "new" technology is unknown, and recommendations and protocols for its best application are not available. This article reviews the limitations of the gray-scale displays currently used, the rationale of the color-supplemented B-mode image, and some of the potential applications to cardiac and vascular ultrasound.