The expansion rate of CIAAs is 0.29 cm/y, and hypertension predicts faster expansion. Because no rupture of a CIAA <3.8 cm was observed, elective repair of asymptomatic patients with CIAA >or=3.5 cm seems justified. Although buttock claudication after EVAR remains a concern, results at 3 years support EVAR as a first-line treatment for most anatomically suitable patients who require CIAA repair. Patients with compressive symptoms or those with AVF should preferentially be treated with OR.
Hepatic arterial occlusion can frequently produce major regression of neuroendocrine tumors with relief from the hormonal syndromes. Sequential chemotherapy may improve the rate and duration of the regression.
Venous reconstructions for iliofemoral or IVC obstruction offer 3-year patency rates of 62%. The Palma procedure with autologous saphenous vein had the best long-term patency, whereas long-term success with ePTFE was moderate. The use of an arteriovenous fistula to improve graft patency remains controversial.
Atherosclerotic renovascular disease (RVD) reduces renal blood flow (RBF) and GFR and accelerates poststenotic kidney (STK) tissue injury. Preclinical studies indicate that mesenchymal stem cells (MSCs) can stimulate angiogenesis and modify immune function in experimental RVD. We assessed the safety and efficacy of adding intra-arterial autologous adipose-derived MSCs into STK to standardized medical treatment in human subjects without revascularization. The intervention group (=14) received a single infusion of MSC (1.0 × 10 or 2.5 × 10 cells/kg; =7 each) plus standardized medical treatment; the medical treatment only group (=14) included subjects matched for age, kidney function, and stenosis severity. We measured cortical and medullary volumes, perfusion, and RBF using multidetector computed tomography. We assessed tissue oxygenation by blood oxygen level-dependent MRI and GFR by iothalamate clearance. MSC infusions were well tolerated. Three months after infusion, cortical perfusion and RBF rose in the STK (151.8-185.5 ml/min, =0.01); contralateral kidney RBF increased (212.7-271.8 ml/min,=0.01); and STK renal hypoxia (percentage of the whole kidney with R2*>30/s) decreased (12.1% [interquartile range, 3.3%-17.8%] to 6.8% [interquartile range, 1.8%-12.9%], =0.04). No changes in RBF occurred in medical treatment only subjects. Single-kidney GFR remained stable after MSC but fell in the medical treatment only group (-3% versus -24%,=0.04). This first-in-man dose-escalation study provides evidence of safety of intra-arterial infusion of autologous MSCs in patients with RVD. MSC infusion without main renal artery revascularization associated with increased renal tissue oxygenation and cortical blood flow.
Vascular occlusive disease poses a threat to kidney viability, but whether the events leading to injury and eventual fibrosis actually entail reduced oxygenation and regional tissue ischemia is unknown. Answering this question has been difficult because of the lack of an adequate method to assess tissue oxygenation in humans. BOLD (blood oxygen-level-dependent) magnetic resonance imaging detects changes in tissue deoxyhemoglobin during maneuvers that affect oxygen consumption, therefore this technique was used to image and analyze cortical and medullary segments of 50 kidneys in 25 subjects undergoing magnetic resonance (MR) angiography to diagnose renal artery stenosis (RAS). Magnetic rate of relaxation (R2*) positively correlates with deoxyhemoglobin levels and was therefore used as a surrogate measure of tissue oxygenation. Furosemide was administered to examine the effect of inhibiting energy-dependent electrolyte transport on tissue oxygenation in subjects with renovascular disease. In 21 kidneys with normal nephrograms, administration of furosemide led to a 20% decrease in medullary R2* (P Ͻ 0.01) and an 11.2% decrease in cortical R2*. In normal-size kidneys downstream of high-grade renal arterial stenoses, R2* was elevated at baseline, but fell after furosemide. In contrast, atrophic kidneys beyond totally occluded renal arteries demonstrated low levels of R2* that did not change after furosemide. In kidneys with multiple arteries, localized renal artery stenoses produced focal elevations of R2*, suggesting areas of deoxyhemoglobin accumulation. These results suggest that BOLD MR coupled with a method to suppress tubular oxygen consumption can be used to evaluate regional tissue oxygenation in the human kidney affected by vascular occlusive disease.
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