Use of the Strecker flexible balloon-expandable tantalum stent for treatment of renal artery stenosis after failed angioplasty or transaortic thromboendarterectomy was evaluated in 10 patients (nine hypertensive, one normotensive). Left (n = 3) and right (n = 5) renal arteries were involved; renal artery stenosis in two patients had developed after kidney transplantation. Indications for stent placement were inadequate immediate postangioplasty response (n = 7), development of considerable restenosis after angioplasty (n = 1), and obstructing intimal flaps following transaortic endarterectomy (n = 2). Stent placement was technically successful (less than 20% residual stenosis) and patency was preserved in eight patients. Of the seven hypertensive patients with successful implantation, two were cured, three had improvement, and two had no change at latest follow-up evaluation (mean, 10.6 months; range, 6-12 months). The Strecker stent may be helpful in treating restenosis after failed revascularization procedures, although the precise indication, true safety, and long-term efficacy of stent placement in renal arteries will not be known until trials with more subjects and longer follow-up periods are completed.

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Three hundred and forty-six carotid arteries were examined with a two-dimensional 3.5 MHz real time scanner in 173 patients with evidence of cerebral ischaemia; 62 carotid arteries were investigated by selective trans-femoral angiography in 36 of these patients at the same time. Sonography and angiography agreed in 20 (91%) of 22 angiographically normal cases, in all cases (10) with haemodynamically insignificant plaques, in eight (66%) of 12 stenosis of less than 50%, in nine (90%) of ten stenosis of more than 50% and in four (44%) of nine total occlusions. Sensitivity of carotid sonography varied with the severity of the lesion from 44 to 100%. Its specificity was 91%. B-scan sonography of the carotid artery, in the presence of cerebro-vascular lesions (transitory ischaemia, cerebral infarcts) and in the presence of non-specific symptoms and of asymptomatic vascular murmurs, may provide indications for the use of angiography. Its values as a screening procedure remains to be assessed.

The distribution and size of atheromatous debris after angioplasty with the Kensey catheter was determined after recanalization of 18 segments of human cadaveric superficial femoral arteries (SFA). The debris produced was studied cytologically and measured semiquantitatively. Nearly 80% of all particles ranged from 5 to 15 microns, approximately the size of red blood cells. More than 20% of all particles exceeded this size and 2% were larger than 100 microns. The use of the Kensey catheter dynamic angioplasty system in the lower extremities contains the risk of embolic complications because more than 20% of all particles are larger than human blood cells. Seven patients with occlusion and 3 with stenoses of the SFA were treated with the Kensey catheter system. Recanalization was successful in all and in 1 case, small emboli in the anterior tibial artery were observed. There was a 50% restenosis/reocclusion rate between 2 weeks and 10 months.

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