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Objective: To determine the value of dobutamine-atropine stress echocardiography and clinical variables to predict perioperative and late cardiac events in patients scheduled for elective major non-cardiac vascular surgery., Design: Blinded prospective study., Patients: Patients (n = 187 mean age 69 yrs)., Measurements: Dobutamine-atropine stress test was performed preoperatively. Results were not used for clinical management. The clinical risk profile was evaluated by Detsky's score., Results: Technically adequate images were obtained in 185/187 patients, one major complication occurred (ventricular fibrillation) and four tests were prematurely stopped due to side effects. Data from 181 patients were analysed. The stress test was positive (new or worsened wall motion abnormality) in 56/181 patients. Perioperative cardiac events were: five fatal myocardial infarctions, three non-fatal myocardial infarctions, nine unstable angina pectoris and one pulmonary edema. All patients with a cardiac event had a positive stress test (18/56). No event occurred in patients with a negative stress test. By multivariate analysis only a new wall motion abnormality during the stress test (odds ratio 45.0, 6-369) was a significant predictor of cardiac events. Patients (n = 154) were followed after operation for 16 +/- 9 months. Twenty-four cardiac events occurred in 21 patients: six fatal myocardial infarctions, three non-fatal myocardial infarctions, six unstable angina pectoris, three ventricular arrhythmias and six congestive heart failures. The stress echo was positive in 19/21 patients with late cardiac events. The cardiac events correlated by multivariate analysis with a history of myocardial infarction (odds ratio 9.6, 1.9-47.7) and new wall motion abnormalities (odds ratio 6.2, 1.5-25.1)., Conclusion: Dobutamine-atropine stress echocardiography is a relatively safe and useful test to identify patients at risk of perioperative and late postoperative cardiac events.

Aim: We have developed a new closed technique using a co-axial catheter embolisation system for intraoperative coil embolisation of the side branches of in situ vein bypass grafts in order to avoid long skin incisions., Technique: After completion of the proximal anastomosis, disruption of the valves and completion of the distal anastomosis, the catheter is introduced via a proximal side branch of the greater saphenous vein. Under fluoroscopic control the side branches are identified, selectively catheterised and an embolisation coil is positioned in each side branch., Patients: In 14 patients (eight men, six women), 16 in situ bypasses were performed (12 below knee femoro-popliteal, four femoro-crural)., Results: Once mastered the embolisation procedure took less than 1 hour. In four cases persistent arteriovenous fistulae had to be treated in the postoperative period. Two major wound complications occurred and there were three early failures. One late failure occurred due to a rupture of the venous bypass 6 weeks postoperatively. The remaining 12 bypasses are patent, with a median follow-up of 16 (3-26) months., Conclusion: These preliminary results suggest that the "closed" technique is feasible and that long term occlusion of AV-fistulae can be achieved without ligation via incisions.

In vitro and in vivo studies revealed significantly better haemodynamic properties for a newly designed axillo-bifemoral bypass graft, with a flowsplitter at the bifurcation. In order to analyse the clinical relevance of these improved haemodynamic properties a prospective randomised clinical trial was performed. The patency rates of two different axillo-bifemoral bypass grafts, differing only in the configuration of the bifurcation: one with a contralateral branch at an angle of 90 degrees and one with a flowsplitter, were analysed. In 19 centres, 117 patients were randomised, 59 receiving a prosthesis with a flowsplitter, and 58 a prosthesis with a 90 degrees bifurcation. Indications and risk factors were equally distributed in both groups. Final analysis after 3 years with a mean follow-up of 12 months (range 3-36 months) showed that the prosthesis with a flowsplitter had a significantly better patency rate after 2 years of 84% compared to the patency rate of the prosthesis with a 90 degrees-angled bifurcation of 38% (log-rank test, p less than 0.0001). These data were not significantly influenced by the indication for the operation, associated risk factors (e.g. diabetes mellitus, hypertension or myocardial infarction), outflow tract or anti-coagulant therapy. Other endpoints such as death and graft infection did not differ significantly.

The usefulness of intra-operative intravascular ultrasound (30 MHz) was evaluated in three patients who underwent a femoropopliteal vein bypass. Intravascular echography analysis of the surgical procedure revealed a normal uneventful result in one patient. In two other patients obstructions in the vein grafts were identified either caused by internal obstruction or external compression. Angiography in these two patients provided equivocal data. We conclude that intravascular ultrasound imaging may be a useful adjunct to angiography and may offer important clinical data to facilitate the surgeons in analysing the results of the interventional procedures.

Aneurysms of the extracranial carotid arteries are uncommon vascular lesions. During the period 1976 to 1986 we encountered 18 extracranial carotid aneurysms in 14 patients. The aneurysms were atherosclerotic (12 in 9 patients), congenital (3 in 2 patients), mycotic (1) and secondary (false aneurysms) after previous carotid surgery (2 in 2 patients). The patients presented with neurological symptoms (11) or a pulsating mass in the neck (2). In one patient the aneurysm was detected accidentally during angiography. From this study it became clear that "carotid aneurysm" is not a well defined entity. The "normal" configuration of the carotid bulb with its usually larger diameter, is in part a cause of the problem of definition. A recently described technique for predicting normal vessel diameters in stenosing lesions of the carotid arteries was retrospectively applied to all our patients with aneurysms. With these measurements, made on standard preoperative angiograms, it was possible to quantify the degree of dilatation, and confirm the diagnosis of aneurysm. Eleven of the 14 patients were operated on without mortality, no neurological deficits were seen as a result of the operation and minimal morbidity occurred in six patients. From this study we conclude that surgical correction of accessible carotid artery aneurysms is a relatively safe procedure and these lesions should be operated on irrespective of symptoms. This is the first report that gives clear guidelines for measuring dilatation of the extracranial carotid arteries and based on these guidelines we suggest criteria for the discrimination between physiological dilatation and pathological aneurysm formation, the latter condition being an indication for operation.

By repeated measurements in each of ten normal subjects and ten patients with mild intermittent claudication, the performance of three transcutaneous oxygen tension (PtcO2) test in the diagnosis of obliterative peripheral arterial disease was studied. PtcO2 resting value, PtcO2 response to oxygen breathing and PtcO2 reperfusion response after tourniquet obstruction were all measured on the dorsum of the foot. We found that PtcO2 resting values were not different between patients and controls, while responses to 100% oxygen breathing and reperfusion responses differed significantly between the two groups. The most prominent difference between the two groups was observed in the latency of PtcO2 rise after reperfusion. Therefore the reperfusion response test may have a place in the assessment of claudication by PtcO2 measurement.

In spite of its unpredictable kinetics, heparin is still not generally monitored during peripheral vascular surgery. To evaluate heparin levels and neutralisation, plasma heparin concentrations were measured using a chromogenic substate method during 20 consecutive operations on the Abdominal Aorta. This was combined with measuring activated partial thromboplastin time (APTT), thrombin time (ThT), prothrombin time (PT), antithrombin-III (AT-III) and fibrinogen concentration. Heparin concentration 5 min after administration and the elimination rate showed a wide variation. Using a standard dosage for all patients resulted in plasma heparin levels that are potentially too low in some patients. The APTT and ThT were found to be unsuitable for an exact calculation of heparin levels. Protamine administration based on the surgeon's judgement of haemostasis was inadequate. Furthermore an intraoperative decrease of AT-III and fibrinogen was seen in eight patients. It is advisable and possible to have direct monitoring of heparin concentration during peripheral vascular surgery.

The feasibility of assessing arterial wall characteristics with an intravascular 40 MHz ultrasonic imaging device was determined in vitro. Ten autopsy specimens of human arteries, with and without atherosclerosis, were studied. A close relationship was observed between the histologic section and the corresponding ultrasonic cross-section with regard to the location, maximum plaque thickness and extent of the atherosclerotic lesion along the circumference of the vessel wall. Based on echogenicity of the atherosclerotic lesion, ultrasound could distinguish four basic types of atherosclerotic plaque components: 1. hypoechoic: a reflection of lipid deposits; 2. soft echoes: reflective of fibromuscular tissue; 3. bright echoes: representative of fibrous tissue; 4. bright echoes with shadowing behind the lesion: representative of calcium deposits. It is anticipated that development of such a catheter-tip imaging system combined with recanalisation methods will be of immense benefit for the precise localisation and identification of vessel wall pathology, precise positioning of a recanalisation instrument (laser device, atherectomy catheter) and subsequent use of this recanalisation procedure and for assessing the effect of recanalisation.