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Endothelial Nitric Oxide Synthase (eNOS) mediates the conversion of L-argine to NO and citrulline, which requires Nicotinamide Adenine Dinucleotide Phosphate (NADPH) as an essential cofactor. Evidence has been given that NOS accounts for the NADPH-diaphorase activity. The aim of the present study was to identify the histochemical and immunocytochemical appearance of NADPH-diaphorase and von Willebrand factor (factor VIII) respectively, in endothelial cells (ECs) during healing of stretch-expanded polytetrafluoroethylene (ePTFE) arterial grafts. On six Swedish domestic pigs an iliac bypass was bilaterally performed using 6 mm stretch-ePTFE grafts. The animals were allowed to survive one, two or four weeks. After explanation the grafts were prepared for NADPH-diaphorase histochemistry and factor VIII immunohistochemistry. Positive staining for the two identification markers was demonstrated after two weeks, whereas a more intense staining was seen after four weeks at the proximal and distal anastomoses, indicating maturation by time. No stained cells were observed at the mid-region of the grafts at any time. The cells differed from normal ECs, the former being less intense which may reflect immature ECs and probably a decreased expression of NO. In conclusion, the present study suggests tha NADPH-d histochemistry can be used to identify ECs. Whether a lower expression of NO compared to normal cells also means a reduced function, capable of causing adverse events has to be further evaluated.

Objective: To analyse the quantity of heparin retention on heparin bonded collagen coated knitted Dacron grafts (HCD) and heparin bonded knitted Dacron grafts without interluminal collagen coating (HD) after they had been exposed to shear stress in an artificial circulation model., Experimental Design: A comparative study., Setting: University Hospital, Department of Surgery., Methods: HCD grafts were exposed to shear stress during 2, 24, 48, and 168 hours, and HD grafts during 1, 2, 3 and 4 weeks. Heparin retention on the graft walls was determined by a method based on the measurements of total sugars., Results: HCD grafts showed no loss of heparin from the graft-surface when exposed to a flow of 200 ml/min up to 168 hrs. HD grafts demonstrated an initial loss of heparin from 8 mg/g to 3 mg/g/graft-segment within one week after which the level was stable during the remaining three weeks., Conclusion: Based on the present experimental setting it seems reasonable to conclude that the heparin-collagen layer remains stable but heparin alone is partly washed out by shear stress. To measure the release of heparin under the influence of the bloodstream including mechanisms for the slow degradation of collagen, a more sensitive method for heparin analysis is required.

Objective: To evaluate the dilatation-rate of a reverse locknitted Dracon graft., Experimental Design: Comparative study, a follow-up after 5 years., Setting: Department of Surgery, University Hospital., Patients: During 1987 to 1990, 105 patients underwent elective aorto-bifemoral bypass surgery for aorto-iliac occlusive disease. Nineteen patients received a reverse locknitted Dacron graft. During follow-up in 1993 ten patients were available for evaluation of graft-diameter. For comparison 14 patients who received a wrap knitted Dacron graft (12 collagen impregnated and two uncoated) operated during the same time period were randomly chosen., Intervention: CT-scan evaluation., Results: A significantly lower increase (a mean aortic body dilatation of 6.8%) of the graft-size was found for this reverse locknitted Dacron (p < 0.001) compared to two wrap knitted Dacron grafts (collagen impregnated and uncoated knitted Dacron) (31.0% and 37.8% respectively). At the femoral level mean dilatation rates of respectively, 2.5%; 23.8% and 31.7% were found. Mural thrombus was observed in three grafts. No false aneurysms, graft degradation or graft occlusions were observed., Conclusion: It was concluded that reverse locknitted Dacron dilates to a minimum, however, further studies are needed to evaluate the relation of graft-composition/structure and dilatation.

Out of 229 patients operated due to abdominal aortic aneurysms, 51 (22.3%) had prolonged (> 120 hours) postoperative intensive care stay. The mortality rate in this group was 27% representing 46% of the total mortality. Twenty-five of these 51 patients had postoperative septic complications, meaning positive blood cultures. Clinically wound infections (11), acalculous cholecystitis (9), urinary tract infections (9), septicemia (6), and diffuse peritonitis or abdominal abscess were found (4). Reoperations, time for ventilatory support, incidence of renal failure and dialysis, gastrointestinal complications and mortality were all frequent in patients with septic postoperative complications as compared to those with non-septic complications, the latter mainly of cardiovascular origin. Signs of organ dysfunction should raise a suspicion of a septic complication and prompt insertion of diagnostic procedures and therapeutic interventions are necessary in order to minimize morbidity and mortality.

The incidence of renal artery stenosis (RAS) was prospectively evaluated by aortofemoral angiography in 100 patients with peripheral vascular disease (PVD) to find whether RAS was a more common finding in hypertensive than in normotensive patients. For a possible association with RAS, risk factors, clinical and angiographical variables were evaluated. Nephrotoxicity of the contrast medium Iohexol was elucidated. A follow-up of six month was performed in patients with severe stenosis or total occlusion of the renal arteries. Of the 49 patients with a renal artery lesion 26.5% were normotensive and 73.5% hypertensive. Hypertension was significantly correlated to RAS. Reconstructive vascular procedures were during the follow-up performed in 47.3% of the patients with severe RAS or occluded renal arteries, two patients underwent a renal artery revascularization, none of them got a postoperative blood pressure decrease. Hypertension in patients with peripheral vascular disease is predictive for renal artery stenosis and a possible renovascular hypertension should be evaluated. Surgery for renal artery stenosis in peripheral vascular diseased patients should, however, probably be performed firstly to reduce the risk for occlusion. The effect on the blood pressure can not be predicted without a more careful analysis that the blood pressure is renin-dependent. Iohexol showed low nephrotoxicity, also in patients with renal artery disease.

To estimate the frequency of renal artery stenosis, and to detect the correlation between renal artery stenosis and hypertension, 450 consecutive patients with peripheral vascular disease (PVD) were selected. All subjects had undergone aorto-femoral conventional angiography. For a possible association with renal artery stenosis, risk factors, clinical and angiographical variables were evaluated e.g.: age, sex, diabetes mellitus, smoking habits, use of antihypertensive drugs, serum creatinine, serum cholesterol, ECG pathology, side of the renal artery lesion, bilateral stenoses, post-stenotic dilatation, number of renal arteries, aortic atherosclerosis, size of the kidneys and angiography induced renal dysfunction. Renal artery stenosis (RAS) was found in 49.1%, 117 patients had a moderate and 104 had a severe stenosis. Of the 221 patients with a renal artery lesion, 44 were normotensive, 177 hypertensive. Hypertension was significantly correlated to RAS. An association was also found for age over 70 years, smoking and pathologic ECG. It is concluded that renal artery stenosis is very common in a population with peripheral vascular disease, and the results achieved from this study makes it worthwhile to identify possible functional markers in a prospective study.