Thromboembolic events (TE) associated with circulatory support devices are a major source of mortality and morbidity. Clinically, the lowest TE rates are claimed with devices that incorporate textured blood-contacting materials. The textured materials currently used in circulatory assist devices are composed of small, attached fibers that form the boundaries of connected cavities. These cavities entrap blood components to form a "neointimal" layer, which is believed to minimize thromboembolic events. We believe that the three-dimensional surface topography of blood-contacting materials is a major controlling factor in the formation of a stable neointimal layer upon the material. Particle-cast cavities were used to form geometric features in segmented polyurethane. This microtextured material was incorporated as part of a flexible blood-contacting surface in a blood pump that was implanted as a left ventricular assist device in calves. The structure, thickness, stability, and development of the neointimal layer were then evaluated. These preliminary studies have shown that a stable neointimal layer can be formed upon the particle-cast surfaces. The results also indicate that the cavity size on the particle-cast surfaces has a significant effect on neointimal adhesion. The methods employed can be used in the design of future circulatory support devices.

Background. The Arrow LionHeart LVD 2000 left ventricular assist device is the first fully implantable system designed for destination therapy. We report on 2 years of experience with this device, which we implanted for the first time in October 1999.Methods. Since October 1999, 6 male patients between 55 and 69 years of age (mean 65 +/- 6 years) have received the device at our center, all were in New York Heart Association functional class IV and ineligible for heart transplantation.Results. All surgical procedures were uneventful, with a timely extubation in 5 of 6 patients. Duration of support was 17 to 670 (mean 245 +/- 138) days, with a cumulative experience of 4.5 years. Three patients recovered to be discharged from hospital under support and are long-term survivors. Three patients died 17, 31, and 112 days after implantation from multiple organ failure without being discharged to their homes. The survival rate is 50% after 18 months. There were no major system-related problems or any device-related infections, which are otherwise commonly found among vertricular assist device patients.Conclusions. Our preliminary experience demonstrates the reliability and efficacy of the different parts of the system. Nevertheless, further sophistication is needed to reduce the size of its components, which so far still constitutes a limiting factor. (C) 2003 by The Society of Thoracic Surgeons.

Left ventricular assist devices (LVADs) were implanted in calves for 30 days. The surface topography of poly(urethane urea) blood sacs retrieved from the LVADs varied with blood pump flow rates and regions with different flow dynamics in the sac. Structures similar to those observed in a fibrin clot were observed in the inlets and outlets. The topography of the region between was distinctively different from that of the inlet and outlet.

Management of patients with end-stage cardiac disease remains a vexing problem. Limitations in medical management and a fixed supply of donor organs for cardiac transplant have a continued impact on this growing population of patients. Mechanical circulatory support has proved very successful as a means of bridging patients to cardiac transplant when all medical options have been exhausted. The development of a chronic system of circulatory support has been underway at the Pennsylvania State University for nearly 30 years. These efforts have been recently merged with the industrial partnership with Arrow International toward the development of the LionHeart LVD-2000 (Arrow International, Reading, PA) completely implanted left ventricular support system. We present an overview of the system, details of implantation, a review of preclinical studies, and a synopsis of the first European implants. Early results have demonstrated the system to be safe, effective, and reliable. Transcutaneous energy transmission and the compliance chamber have been validated.

Background. Two modifications of the surgical implantation protocol for the Penn State Total Artificial Heart (ETAH) were evaluated: Phrenic nerve ischemia was prevented by minimizing dissection and traction; and hemostasis was augmented and ETAH cuff anastomoses reinforced by using fibrin glue.Methods. Thirteen Holstein calves underwent orthotopic surgical implantation of the Penn State ETAH between February 1998 and August 2000. Mean hemodynamic and laboratory chemistry variables from the first postoperative week were compared between calves receiving the original (n = 7) and modified (n = 6) protocol.Results. Calves assigned to the modified protocol displayed an improvement in the PO2/FiO(2) ratio compared to original (419.4 +/- 17.5 vs 336.3 +/- 35.4, respectively; p = 0.05). All additional parameters were equivalent between groups. The percent survival of animals receiving the modified protocol at 2, 4, and 12 weeks was higher than that of animals that underwent the original protocol. Original-protocol calf deaths consisting of hemothorax (n = 3), and respiratory failure (n = 1) were prevented in the modified protocol.Conclusions. Our results suggest that manipulations in surgical protocol may promote increased survival in calves implanted with the Penn State ETAH. (C) 2001 by The Society of Thoracic Surgeons.

Surgery for the repair of a type I aortic dissection presents several difficulties for the surgeon and the perfusionist. One must safely support the patient, while at the same time provide the surgeon with a bloodless field in which to operate. Often, this requires cessation of the circulation for varying amounts of time. Deep hypothermia allows for an extension of the arrest period, while other techniques - retrograde cerebral perfusion and antegrade cerebral perfusion - provide an additional degree of cerebral protection. Recently, we utilized these techniques concurrently on a 43-year-old female who presented for a reoperation for a type I aortic dissection. Combining these techniques allowed us to adequately support the patient during an anticipated lengthy period of circulatory arrest and insured a successful operation without any adverse cerebral or other organ dysfunction.

PURPOSE:A modification of radical nephrectomy for renal carcinoma and vena caval tumor thrombectomy for supradiaphragmatic tumor extension under hypothermic circulatory arrest is presented.MATERIALS AND METHODS:Nephrectomy was performed during the circulatory arrest time in 16 consecutive patients during the last 4 years.RESULTS:Average hypothermic circulatory arrest time increased by 6 minutes. By elimination of manipulation of tumor and thrombus before circulatory arrest potential thrombus fragmentation and embolization were minimized. There were no significant differences in blood loss or complications compared to a prior series of 10 patients undergoing the procedure using conventional techniques.CONCLUSIONS:Performance of complete radical nephrectomy along with venal caval embolectomy during circulatory arrest increases the safety of the procedure without significant morbidity.

The development of a completely implanted total artificial heart at our institution has progressed to successful in vivo and in vitro testing of a device that is nearing clinical testing. This system consists of a 70 cc stroke volume pump originally designed to be used in men of average stature. Implantation of this system remains limited by patient size; hence, many women and adolescent patients will likely be precluded from support because of their smaller stature. A system similar in design, but with a 50 cc stroke volume pump has been developed. The first in vivo study of this device has been undertaken. A calf was supported for 33 days. The animal was extubated and ambulatory within the first 6 hours of implantation, and remained healthy until the thirty-third postoperative day when it suffered an embolic neurologic event, The pump and operating system worked flawlessly throughout the period of support. Further in vivo and in vitro testing will be undertaken. Development of a scaled down total artificial heart system expands this type of circulatory support to those critically ill patients previously deemed poor candidates because of their smaller body habitus.

Total Artificial Heart (TAH) development at Penn State University and 3M Health Care has progressed from design improvements and manufacturing documentation to in vitro and in vivo testing to characterize the system's hemodynamic response and energetic performance. The TAH system is completely implantable and intended for use as an alternative to transplantation. It includes a dual pusher plate pump and rollerscrew actuator, welded electronics and battery assembly, transcutaneous energy transmission system, telemetry, and a compliance chamber. In vitro testing was conducted on a Penn State mock circulatory loop with glycerol/water solution at body temperature. Tests were performed to characterize the preload and afterload response, left atrial pressure control, and power consumption. A sensitive preload response was demonstrated with left atrial pressure safely maintained at less than 15 mm Hg for flow rates up to 7.5 L/min. Variations in aortic pressure and pulmonary vascular resistance were found to have minimal effects on the preload sensitivity and left atrial pressure control. In vivo testing of the completely implanted system in its final configuration was carried out in two acute studies using implanted temperature sensors mounted on the electronics, motor, and energy transmission coil in contact with adjacent tissue. The mean temperature at the device-tissue interface was less than 4 degrees C above core temperature.

Background: Conventional cineradiology has been used clinically to detect partially broken outlet struts (single leg separations, SLSs) in normally functioning Björk-Shiley convexo-concave (C/C) heart valves. The value of radiographic screening has, however, been debated in the medical literature. This study uses the same radiographic technique in sheep implanted with known-status C/C valves in combination with a newly developed geometric image magnification radiography system. This study was designed to test whether sensitivity and specificity of radiographic screening of C/C valves in detecting SLSs could be improved through the combination of readers and imaging modalities. Methods: Twenty-one sheep with mitral C/C valves were studied on both systems. Five were used for extensive scanning training. When operators were expert on both systems, 16 blinded study valves (4 intact and 12 with outlet strut SLSs) were scanned twice on both systems, first on a modified conventional and then a prototype geometric image magnification (FeinfocusTM) cineradiographic system by two expert physicians working together. Results: Among the 32 scanned valves, the two combined expert physicians were required to evaluate 40 intact legs and 24 with an SLS. For all SLS valves, the conventional and Feinfocus systems separately detected 50 (12/24) and 54% (13/24), respectively. When the two systems were combined, the final consensus score was correct in 67% (16/24) of all SLS valves. Conclusions: Combined modality, paired expert physicians detected 67% of all SLSs. The Feinfocus system might be best reserved for those patients in whom the Siemens screening study demonstrates in minimally suspicious (grade 2) or suspicious (grade 3) appearance of a C/C valve outlet strut leg.

BACKGROUND:During the past decade, ventricular assist devices as a bridge to transplantation have moved from the experimental arena to accepted therapy. Our institution has been at the forefront of the development of this technology and consequently has had extensive experience with the devices that are currently approved by the Food and Drug Administration for use as a bridge to heart transplantation.METHODS:The successful management of patients with assist devices hinges on patient and device selection as well as perioperative management strategies. The routine use of agents such as aprotinin, vasopressin, milrinone, and inhaled nitric oxide has contributed to successful management of these patients. We present our perspectives on the advantages and disadvantages of the Thermo-Cardiosystems HeartMate 1000 IP device and the Thoratec (Pierce-Donachy) system. We also discuss our protocols and methods for patient selection, preoperative preparation, intraoperative strategy, and postoperative management that have resulted in improved patient outcomes.RESULTS:More than 60 device implantation procedures have been performed since the inception of our bridge to transplantation program. During this time, two thirds of our patients were successfully bridged to transplantation. Of these patients, 92% were alive at 1 month after transplantation, and 83% were alive at 1 year after transplantation.CONCLUSIONS:Both support systems are effective in supporting patients to heart transplantation. We have developed a preference for the Thermo-Cardiosystems HeartMate 1000 IP device because of its portability and associated better quality of life. However, the Thoratec device is the more versatile device, and circumstances exist when its use is clearly advantageous. In our institutional experience, outcome for bridging to transplantation has not been device dependent.

We analyzed the mechanism of effects of intra-aortic balloon pumping using the pressure-volume relationship and ventriculoarterial coupling in the normal and failing hearts. Materials: In 12 anesthetized Holstein calves ( weight, 93 +/- 8 kg), the ventricular end-systolic and arterial elastances, pressure-volume area, and external work were analyzed during steady-state contractions with traditional hemodynamic parameters with intra-aortic balloon pumping-off and -on (1:1 synchronous ratio). An acute ischemic heart failure was induced by injecting 10 mu m microspheres (4.2 +/- 1.8 x 10(7 .)100g left ventricular weight(-1)) into the left main coronary artery; all measurements were repeated, Results: Intraaortic balloon pumping did not change hemodynamic parameters in the control. However, during heart failure, intra-aortic balloon pumping decreased the arterial elastance from 3.6 +/- 3.3 mm Hg to 2.9 +/- 1.2 mm Hg . mL(-1) while not affecting the ventricular end-systolic elastance, this resulted in an improvement of the ventriculoarterial coupling ratio from 3.1 +/- 0.8 to 2.3 +/- 0.8, Intra-aortic balloon pumping decreased not only end-systolic pressure (from 69 +/- 16 mm Hg to 64 +/- 19 mm Hg) but end-diastolic volume and pressure (from 139 +/- 38 mt to 137 +/- 37 mt and from 13.9 mm Hg to 12.8 mm Hg, respectively) with the leftward shift of the pressure-volume loop. Pressure-volume area decreased (from 914 +/- 284 mm Hg to 849 +/- 278 mm Hg mt) although stroke volume increased (from 21 +/- 6 mt to 24 +/- 6 mL). Conclusion: Reduction of the arterial elastance with intra-aortic balloon pumping improved the ventriculoarterial coupling ratio and increased stroke volume. Leftward shift of the pressure-volume loop resulted in the reduction of pressure-volume area, which suggests the conservation of the myocardial oxygen consumption.

Naccarelli, Gerald V. MD; Luck, Jerry C. MD; Wolbrette, Deborah L. MD; Pae, Walter E. MD; Weller-Moore, Rhonda RN; Dell’Orfano, Joseph T. MD; Patel, Hemantkumar M. MD; Boehmer, John P. MD Author Information

Objective: Modified cineradiographic systems have been used clinically to detect partially broken outlet struts in normally functioning Bjork-Shiley convexo-concave heart valves, Almost all such valves were explanted, presuming that full failure would likely follow Inasmuch as the clinical setting only rarely permits examination of normally rated valves, the accuracy of radiographic detection cannot be clinically defined, This study uses the clinical radiographic technique in sheep implanted with known status convexo-concave valves, comparing its accuracy and that of a newly developed, geometric image magnification radiography system, Methods: Twenty-one sheep with mitral convexo-concave valves were studied on both systems, Five were used for extensive training, When operators were expert with both systems, images of four intact valves and 12 valves with outlet strut single leg separations, along with a seventeenth single leg separation valve used for calibration, were integrated into 112 image sets organized into a balanced incomplete block design for evaluation by eight trained, blinded reviewers, Results: Cineradiography sensitivity vas 24% versus 31% for direct image magnification, The odds ratio for detection of single leg separation by direct image magnification versus cineradiography was 2.0 (95% confidence interval, 0.76 to 5.9; p = 0.13), Cineradiography specificity was 93% versus 90% for direct image magnification, Sensitivity and specificity varied markedly by reviewer, with sensitivity ranging from 8% to 55% and specificity from 51% to 100% for the combined technologies, Conclusions: The data support the need for more intensive training for convexo-concave valve imaging and further investigation of unconventional radiographic technologies, Clinical cineradiography of convexo-concave valves may detect as little as 25% of valves having a single leg separation, underestimating the prevalence of single leg separations and thereby implying more rapid progression to full fracture than is actually the case.

The voluntary submission of data on patients who receive mechanical circulatory assistance for post cardiotomy cardiogenic shock and acute myocardial infarction has resulted in an established data base for the ongoing evaluation of these devices. Since its inception in 1985, there have been 1,279 cases reported of implanted ventricular assist devices for post cardiotomy cardiogenic shock. The average duration of support for these devices is approximately 4 days. Those patients who underwent implantation of a centrifugal pump had significantly shorter periods of support when compared with the pneumatically supported group. Patients had similar periods of support when comparing clinical outcome. Approximately 70% of the reported cases underwent centrifugal assistance. The majority of reported cases were supported with isolated left ventricular assistance. There was no significant difference in overall outcome statistics when comparing type or mode of support. Approximately 45% of reported patients were weaned from circulatory assistance, and 25% of all patients survived to discharge. These numbers remain consistent with previously reported statistics. The results with acute myocardial infarction remain limited. Of the 96 reported patients, 26% were weaned from support and only 11.5% survived to discharge. This report continues to support the use and research for advancement of these devices toward the treatment of post cardiotomy cardiogenic shock.

We present the case of a patient who underwent implantation of a left ventricular assist device (LVAD) as a bridge to transplantation and subsequently had disruption of the Dacron inflow graft of the pump. Surgical investigation at the development of expanding hematoma and drive line bleeding resulted in entrainment of air into the pump, massive air embolus, and subsequent death of the patient. We believe that this case demonstrates the need for angiographic definition of bleeding associated with a completely implanted LVAD before surgical exploration, as well as specific surgical strategies to avoid air embolus. A 64-year-old man was admitted to our institution with a history of progressive cardiac failure. He had had aortic valve replacement with a porcine prosthesis and implantation of a pacemaker 7 years before this admission. An extensive evaluation indicated end-stage dilated cardiomyopathy. The patient was activated on the waiting list for cardiac transplantation. Despite a regimen of dopamine, dobutamine, amrinone, and intravenous diuretics, the patient had progressive symptoms of cardiac failure. An intraaortic balloon pump was inserted, with only marginal improvement in hemodynamics. Despite this aggressive conventional management, the patient had progressive deterioration and thus underwent preperitoneal implantation1McCarthy PM Wang N Vargo R Preperitoneal insertion of the Heartmate 1000 IP implantable left ventricular assist device.Ann Thorac Surg. 1994; 57: 634-638Abstract Full Text PDF PubMed Scopus (62) Google Scholar, 2Radovancevic B Frazier OH Duncan JM Implantation technique for the Heartmate left ventricular assist device.J Card Surg. 1992; 7: 203-207Crossref PubMed Scopus (35) Google Scholar of the Thermo Cardiosystems Incorporated (TCI) Heartmate LVAD (Woburn, Mass.) 2 months after admission. The initial postoperative course was uneventful except for transient failure of the right side of the heart, responsive to dopamine, during the first postoperative week and thoracentesis on two occasions in the early postoperative course for recurrent left pleural effusion with drainage on each occasion of approximately 1 L of serous fluid. On postoperative day 32 the patient was evaluated on an emergency basis for brisk bleeding around the drive line site, and physical examination confirmed an expanding collection of fluid within the preperitoneal implantation pocket. The patient was promptly taken to the operating room for suspected bleeding within the preperitoneal pocket. The preperitoneal pocket was opened and noted to have a collection of approximately 2 L of dark clotted blood. This collection was removed to identify the underlying bleeding site, which was quickly identified to be a defect in the inlet cannula of the pump. The patient's chest was promptly opened and cardiopulmonary bypass initiated. The pump was stopped and the cannula evaluated. Unfortunately, despite rapid and aggressive intervention, the patient's heart, aorta, and pump were noted to be filled with entrained air. The patient died shortly thereafter in the operating room. An autopsy subsequently revealed that the cage support had eroded through and resulted in a 2 cm laceration in the Dacron inlet graft (Fig. 1). This laceration was located at the level of the diaphragm, with consequent subdiaphragmatic blood collection, likely the source of the recurrent serous pleural effusions on that side. No other abnormalities associated with the pump or its implantation were noted at that time. To our knowledge this is the first case of its kind that has been reported in the literature. After this event, personal communication has revealed that other institutions have had similar problems with the inlet cannulas, which subsequently resulted in a design change and voluntary recall of the inlet assembly by TCI. A patient who has periodic or persistent bleeding at any time after implantation should be treated with the utmost caution; however, as the time after implantation increases, bleeding is less likely to be a function of surgical technique. The initial management of these patients should be centered on aggressive resuscitation, including transfusion as necessary, and correction of any aberrations in coagulation factors. Early angiographic evaluation is warranted to avoid progressive problems with these patients. Angiography should reveal any large breaks in the integrity of the pumping system. A diagnostic angiogram, a nondiagnostic study with persistent evidence of bleeding, or a patient whose condition is too unstable to tolerate angiographic evaluation warrants immediate operative exploration. However, all care must be taken to control the device during the evaluation to prevent potential entrainment of air within the system, as has been previously described for explantation of these devices at the time of transplantation.3Oz MC Levin HR Rose EA Technique for removal of left ventricular assist devices.Ann Thorac Surg. 1994; 58: 257-258PubMed Google Scholar These patients are dependent on augmented flow from these devices to sustain adequate perfusion. Hence weaning from the device before exploration is not a feasible option in most patients. The safest approach appears to be aggressive intervention by initiation of femoral-femoral cardiopulmonary bypass, thus allowing cessation of LVAD pumping before wide exploration of the circuit, anastomotic sites, and pockets. Any necessary interventions including complete pump replacement may then be undertaken while the patient is maintained with cardiopulmonary bypass. Although this intervention may appear excessive for an unclear cause of bleeding, our case demonstrates that these patients may have significant problems with circuit continuity of the LVAD without manifesting significant clinical symptoms. Therefore we believe that early and aggressive management is warranted, because the consequences of exploration can prove devastating.

BACKGROUND:Pneumatic artificial hearts have played an important role in supporting the circulation in patients before cardiac transplantation. Pneumatic hearts have also been used for permanent cardiac replacement, but most agree they have serious limitations.METHODS:Several groups are now developing electric artificial hearts in which electrical energy crosses the skin using a wireless technique. The electrical energy powers a small direct-current motor, which actuates the blood pump.RESULTS:Important progress in these devices has resulted in animal survival with electric hearts of more than 1 year.CONCLUSIONS:Extensive bench testing and animal testing will be performed before the initial clinical use of these devices will be initiated. One of the early scientific achievements of the 21st century will be the initial use of the electric artificial heart in humans.

Implantation of ventricular assist devices (VADs) to support patients awaiting cardiac transplant has become an effective means of assuring that these critically ill patients survive to transplant. The authors undertook a retrospective analysis of 115 consecutive patients listed for cardiac transplant from January 1992 through June 1995. A VAD was implanted in 19 of these patients. Survival was calculated by intent to treat from the time of transplant listing through heart transplant, if it occurred. The analysis demonstrates that the patients who underwent implantation of a VAD as bridge to transplant had survival times similar to those of patients with medical management. These survival statistics demonstrate the utility of VADs as an effective means to bridge critically ill patients until a suitable donor organ becomes available. In addition, as previous studies have suggested for acute results, earlier implementation and better patient selection may lead to improved long-term survival.

BACKGROUND:Heightened awareness of medical costs has escalated criticism toward expensive medical therapy. METHODS:The use of ventricular assistance devices (VADs) at Pennsylvania State University as a bridge to transplantation was reviewed. Records of 43 patients listed as status 1 from July 1991 to July 1994 were compared. RESULTS:This analysis demonstrated that for all patients treated with the intent to transplant, those who were bridged with a VAD exhibited a trend toward an improved transplantation rate (92% versus 68%) and a significantly greater rate of discharge from the hospital (92% versus 55.4%; p = 0.023) than the medically managed patients. Although overall charges and costs were higher in VAD-supported patients, this was related to significantly longer pretransplantation hospitalization. When normalized to daily costs and charges, this discrepancy in expenses was eliminated. CONCLUSIONS:The superior rate of discharge at equitable daily costs and charges for the VAD patients draws continued enthusiasm toward use of these devices as a bridge to transplantation. Furthermore, development of outpatient care for VAD-supported patients and continued advances in the use of these devices may further reduce the cost of managing these critically ill patients.