No abstract

We have examined effects of chronic reduction of intraluminal PO2 on blood flow through vasa vasorum, by comparing large arteries and veins, and effects of acute hypoxia on flow through vasa. Microspheres were used to measure flow in anesthetized dogs. Values obtained with different sizes of microspheres suggest that spheres 9 and 15 micron in diam, but not 50 micron, are appropriate for measurement of blood flow through vasa vasorum. Flow [expressed as ml X min-1 X 100 g-1 (SE)] through medial vasa was similar in the aorta (9.0 +/- 2.1) and pulmonary artery (9.3 +/- 1.1) although, on the basis of wall thickness and number of lamellae, one would predict much higher levels of flow to aortic media. Two veins that we studied have a thick muscular wall. Both veins had high levels of flow through medial vasa: 33 +/- 4.4 to the subdiaphragmatic inferior vena cava and 18 +/- 5.4 to the portal vein. Two other veins are apparently conduit vessels, with dense connective tissue and minimal smooth muscle. Both veins had minimal flow through medial vasa: 2.4 +/- 1.0 to superior vena cava, and 1.9 +/- 0.8 to supradiaphragmatic inferior vena cava. Thus, because flow through vasa differs greatly in different veins, structure of the vessel (as well as intraluminal PO2) is an important determinant of flow through vasa. Acute hypoxia increased conductance of medial vasa vasorum of arteries and veins when neurohumoral constrictor effects were blocked by phenoxybenzamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Early restenosis or reocclusion after endovascular intervention of lesions in the above-knee femoro-popliteal artery was more frequent following treatment of occlusion (versus stenosis), for patients with diabetes, patients with elevated D-dimer and those without antithrombotic therapy after the procedure. Plasma homocysteine did not appear to influence the outcome of endovascular intervention.

Further studies are needed to define subgroups unsuitable for elective surgery.

Objectives: To report the results of surgical treatment of popliteal aneurysms with respect to symptoms and aneurysm size.Design: A retrospective study based on prospectively registered data, in a single vascular unit.Patients and Methods: Forty-nine patients were subjected to 57 operations from May 1974 to June 2000. Patency and limb salvage rates are compared for limbs with and without symptoms of ischaemia, and for small (2 cm or less) and large (> 2 cm) aneurysms. The long-term survival rate was calculated and compared with that of an age and sexmatched population.Results: The overall 5 year graft patency was 60 %. It was 83 % for asymptomatic limbs and 49 % for limbs with ischaemic symptoms. This difference was significant (p < 0,05). The overall 5 year limb salvage rate was 76 %. It was 100 % for asymptomatic and 64 % for symptomatic limbs and this difference was significant (p < 0,05). Twenty-one of the aneurysms were 2 cm or less in diameter and 85 % of these caused symptoms of ischemia. The operative mortality was 4 %. The 5-year survival rate was 57 % and significantly lower than that of a demographically matched population. Conclusion:The results of prophylactic operations for popliteal aneurysms on asymptomatic limbs are significantly better than those of operations done on limbs with ischaemic symptoms. The aneurysm size at which to recommend surgery is still not settled.

Age at the time of the operation for a symptomatic abdominal aortic aneurysm does not seem to influence long-term survival. Consequently, younger patients experience a higher relative mortality compared to the older.

No abstract

No abstract