Misra, Sanjay

We present the midterm clinical outcomes and predictors of balloon angioplasty and stent placement in atherosclerotic femoropopliteal (FP) arterial disease. Between January 2002 and August 2006, 155 patients (men = 56%; 71.4 ± 10.5 years) underwent 171 FP angioplasty or stent for claudication (n = 82, 54%) or critical limb ischemia ([CLI] n = 70, 46%). Follow-up was obtained through September 30, 2009. The average follow-up was 3.25 ± 1.73 years. In claudicants versus CLI, the 12-month patency for TransAtlantic InterSociety Consensus II (TASC II) classification (TASC A/B) was 93% versus 80%, respectively, and TASC C/D 83% versus 80%. At 3 years, TASC A/B was 82% versus 80%, respectively, and TASC C/D was 56% versus 80%, respectively. The predictor of clinical failure in claudicants was chronic renal insufficiency (CRI) and in CLI, the predictor of amputation was hyperlipidemia.

Atherosclerotic renal artery stenosis reduces blood flow and perfusion pressures to the poststenotic kidney producing renovascular hypertension and threatening glomerular filtration rate. Little is known regarding regional tissue oxygenation in human renovascular disease that develops slowly. We compared stenotic and contralateral kidneys regarding volume, tissue perfusion, blood flow measured by multidetector computed tomography, and blood oxygen level–dependent magnetic resonance values in the cortex and medulla in 14 patients with unilateral stenosis (mean: 71% by quantitative computed tomography) and in 14 essential hypertensive patients during 150 mEq/d of sodium intake and renin-angiotensin blockade. Stenotic kidney volume was reduced compared with the contralateral kidney (118.6±9.9 versus 155.4±13.7 mL; P <0.01), as was total blood flow (269.7±42.2 versus 383.7±49; P =0.02), mainly because of reduced cortical volume. Tissue perfusion was similar but lower than essential hypertension (1.5 versus 1.2 mL/min per milliliter; P <0.05). Blood oxygen level–dependent MR at 3 T confirmed elevated R2* values (a measure of deoxyhemoglobin) in deep medullary regions in all 3 sets of kidneys (38.9±0.7 versus cortex 17.8±0.36 s −1 ; P <0.0001). Despite reduced blood flow, R2* values did not differ between atherosclerotic and essential hypertensive kidneys, although furosemide-suppressible fall in medullary R2* was reduced in stenotic kidneys (5.7±1.8 versus 9.4±1.9 s −1 ; P <0.05). Renal venous oxygen levels from the stenotic kidney were higher than those from essential hypertensives (65.1±2.2 versus 58.1±1.2; P =0.006). These data indicate that, although stenosis reduced blood flow and volume, cortical and medullary oxygenation was preserved under these conditions.

Purpose The purpose of the present article was to determine the changes in luminal vessel area, blood flow, and wall shear stress in both the inflow artery and the venous stenosis of arteriovenous polytetrafluoroethylene (PTFE) grafts. Methods and materials Polytetrafluoroethylene grafts were placed from the carotid artery to the ipsilateral jugular vein in 8 castrated juvenile male pigs. Contrast-enhanced magnetic resonance angiography (MRA) with cine phase-contrast magnetic resonance imaging (MRI) was performed 2 weeks after graft placement. Results The mean wall shear stress at the venous stenosis was 4 times higher than the control vein, while the inflow artery was only 2-fold higher. By day 14, venous stenosis had formed, which was characterized by narrowed area and elevated blood flow. Conclusion By day 14, there is venous stenosis formation in porcine arteriovenous PTFE grafts with increased shear stress with decreased area when compared to control vein.