Objective: To compare two methods of detecting graft stenoses after infrainguinal bypass.Design: Prospective study.Setting: Vascular Laboratory, University Hospital.Materials: 110 infrainguinal graft studies (60 vein, 50 PTFE) in 74 patients were performed prospectively to detect graft-related stenoses.Chief Outcome Measures: The diagnostic accuracy of computer assisted impedance analysis was assessed using Quickscan (QS) as the gold standard in the detection of graft-related stenoses.Chief Results: QS showed occlusion in 4 grafts (two vein and two PTFE), no stenosis in 86 graft studies and stenoses in 20 studies. All 12 stenoses with a frequency ratio greater than or equal to 1:4, were confirmed with intraarterial digital substraction angiography (IADSA). Eight stenoses with a frequency ratio of 1:3 continued graft surveillance. The median thigh impedance score of vein grafts with QS confirmed stenoses was 0.51 (0.36-0.70) compared with 0.44 (0.30-0.60) for non-stenosed vein grafts (p=0.015, Mann-Whitney U test). The median thigh impedance score in PTFE graft with QS confirmed stenosis was 0.58 (0.53-0.76) compared with 0.42 (0.28-0.73) for non-stenosed grafts (p=0.0001). An impedance score > 0.45 has been suggested for detection of ''at risk'' grafts. Using QS as the gold standard, impedance assessment gave 90% sensitivity, 63% specificity in the thigh; 80%, 52% in the calf and 90%, 46% taking the higher score on calf or thigh data. Taking a QS frequency ratio of 1:4 as indicating a significant stenosis (50% diameter reduction), 11% (12/106) of surveillance studies went on to intervention, that is 12/74(16%) grafts.Conclusions: If the higher impedance score derived from either the calf or thigh was used to detect stenoses, 60% (64/106) of graft studies would have been referred far intervention. We believe this high level of intervention is unrealistic and cannot therefore recommend impedance analysis for graft surveillance.

The prevalence of peripheral vascular disease demands a quick, reliable, non-invasive technique for initial assessment. We have devised a new method which combines the two physical principles that (1) Doppler shift is proportional to blood velocity and (2) blood velocity is inversely proportional to arterial cross-section with the ability to track probe position using a non-contacting method. An image of the probe track and any arterial narrowing is shown superimposed on an outline of the patient. Pressure measurement, scan and graphics with final report take about 20 minutes. The accuracy of this system in peripheral vascular disease was evaluated. Thirty-one patients underwent quickscan (QS) and arteriography within an average time of 7 days. Abdominal aorta, common iliac-common femoral, superficial femoral and popliteal artery segments were graded independently as normal, significant stenosis (greater than 50% of diameter) or occluded by both techniques. Of 197 segments, QS correctly assessed 106 normal, 22 stenosed and 28 occluded segments. Four equivocal angiographic stenoses were normal on QS and three severe stenoses were graded occlusion. Fifteen segments on angiography and five on QS were not assessed. For the iliac and superficial femoral artery segments, sensitivity and specificity averaged 77% and 86%, respectively, for all grades. Aortic statistics were invalid (only one significant lesion). Six out of eight popliteal occlusions were correctly diagnosed by QS, but no popliteal stenoses were detected out of six shown on arteriography. Low numbers may contribute to this discrepancy but an improved popliteal scanning method may be necessary. We find initial QS an invaluable aid to direct percutaneous angiography and to indicate potential sites for angioplasty.

Two electrophoretically distinct but morphologically cryptic forms of Antechinus 'stuartii', designated 'northern' and 'southern', occur together at Kioloa on the southern coast of New South Wales. These forms are distinguished by fixed allele differences in three proteins (albumin, glycollate oxidase and mannosephosphate isomerase) and by differences in allele frequencies for transferrin, and are separated by a Nei D of 0.11. The two forms are reproductively isolated in sympatry at Kioloa by asynchrony in the timing of reproduction, and may be considered separate biological species. Northern form populations were identified by screening for albumin and transferrin in seven localities on the central coast of New South Wales north of Kioloa. Southern form populations were identified similarly in 13 localities south of Kioloa and inland along the Great Dividing Range, and at a further locality in southern Victoria. Ovulation occurs at different rates of change of photoperiod in the two species, and may ensure that reproductive isolation is maintained in all potential areas of sympatry. The northern form represents A. stuartii sensu stricto and ranges from Kioloa north into south-eastern Queensland. The southern form is an undescribed species of Antechinus that appears to be widely distributed throughout southern New South Wales and Victoria.

A method is described for non-invasively measuring the increase in lower limb blood flow during transfemoral lumbar aortography. Flow measurements were made using a continuous wave Doppler-shift ultrasound transducer placed over the contralateral femoral artery. The effect of the non-ionic contrast medium B15000 (Iopamidol), conventional contrast medium (Urografin 370) and Urografin 370 plus Lignocaine were compared in a double-blind trial. All three produced an increase in flow which reached a peak between 12 and 45 s after injection. The peak flow following Iopamidol was significantly lower than that from both Urografin 370 alone and with addition of Lignocaine. There was a difference of lesser degree between Urografin 370 plus Lignocaine and Urografin 370 alone; however, this was not statistically significant. The subjective assessments of pain and patient 'discomfort' paralleled these objective flow measurements.

A technique for determining the filial relationships of free-living small mammals is described. The radioisotope 35*sulfur is injected into a lactating mother, and this passes from the milk and is incorporated in the growing hairs of the young. In three species, Mus musculus and Rattus fuscipes (Rodentia) and Antechinus stuartii (Marsupialia), radioactivity in the hairs of the young was detected for up to 130 days after injection of the mother. The technique has the following advantages: (1) the half-life of 35*S is only 87.4 days; (2) 35*S had no evident adverse effects; (3) different treatments, ranging from 0.75 Ci [27.75 kBq] g- to 4.25 Ci [157.25 kBq] g- body weight of the mothers, resulted in different levels of radioactivity in the hair of the juveniles; consequently, the filial relationships of several mothers and their young may be established. The application of this technique to field studies of small mammals is outlined.

Pressure pulses were recorded simultaneously at the aortic/external iliac junction and in the abdominal aorta of six normal dogs at a distance 7—10 cm upstream of the junction. The matched abdominal aortic equitrifurcation was then transformed, in vivo, to an unmatched equibifurcation by temporary occlusion of the central branch and the pressure recording procedure repeated. An increase in the oscillatory pressure amplitudes at the junction was observed as a result of the unmatching procedure. At the upstream site the amplitude increase was similar to the junction site for only the first two harmonics of the pressure pulse. These changes were interpreted as being due to increased reflection from the unmatched junction and alteration in the peripherally reflected pressure waves reaching the aorta.

The construction of bifurcation grafts is such that the flow velocity in the branches is twice that in the parent vessel. This sudden increase in velocity leads to turbulence generation at comparatively low aortic velocities, ie., ∼35 cm sec −1 . The physiological consequences of turbulence are discussed.

Investigation of the vascular system using ultrasonic Doppler-shift techniques is rapidly attracting clinical attention. Frequently the technique is used to provide a sophisticated form of stethoscope with a rather non-specific indication of blood flow-velocity, or less frequently for the production of flowvelocity pulse wave shapes. Detailed analysis of these pulse wave shapes has not been reported. However it is known that partial obstruction of the arterial pathway and the presence of collateral vessels produces damping of the pulse

ArticleAudio signals in arteriovenous shunts: use in flow monitoring and possible relevance to clotting.R G Gosling, and D H KingR G Gosling, and D H KingPublished Online:01 Jul 1969https://doi.org/10.1152/jappl.1969.27.1.106MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByThe origin and the progression of varicose veinsMedical Hypotheses, Vol. 37, No. 4Is circulating noradrenaline the cause of varicose veins?Medical Hypotheses, Vol. 34, No. 3Turbulence in bifurcation graftsJournal of Surgical Research, Vol. 13, No. 2 More from this issue > Volume 27Issue 1July 1969Pages 106-11 https://doi.org/10.1152/jappl.1969.27.1.106PubMed5786952History Published online 1 July 1969 Published in print 1 July 1969 Metrics