Percutaneous stent-in-stent placement for renal artery stenosis of a solitary functioning kidney
A 37 year old male presented with a history of hypertension for the last 3 years. He was not a smoker and had no family history of hypertension. The blood pressure was 220/120 mm of Hg despite being on nifedipine 20 mg thrice daily, prazosin 5 mg twice daily and clonidine 0.1 mg 3 times daily. He was found to have severe renal insufficiency (serum creatinine: 8.9 mg/dl), hypokalemia (serum potassium 2.9 meq/l), bland urine sediment, contracted left kidney (6.3 cm × 3.4 cm) and normal sized right kidney (9.4 cm × 4.0 cm) with increased echotexture. The cardiac evaluation showed concentric left ventricular hypertrophy with good LV function (EF: 71%) and mild diastolic dysfunction. Color Doppler showed high resistive indices (RI > 1.0) and peak systolic velocity (>180 cm/sec) in both main renal arteries suggesting ostial stenosis. Renal arteriogram showed hemodynamically significant ostial stenosis on both sides. Renal angioplasty and stenting was carried out on the right side with balloon expandable chromium cobalt stent. He received 5000 units of unfractionated heparin in the post procedure period and was started on anti-platelet agents. His serum creatinine decerased to 1.5 mg/dl over the next 4 weeks. The blood pressures were within the normal range on 40 mg of nifedipine daily. He continued to use anti-platelet agents (aspirin 150 mg and clopidogrel 75 mg daily).\nHe presented with flash pulmonary edema after 1½ years of initial stent placement. When his follow-up visits with the local physician were reviewed it revealed a slowly rising blood pressure levels for which an angiotensin converting enzyme inhibitor (ramipril 5 mg) was added in the last 2 weeks. Re-evaluation showed severe renal insufficiency (serum creatinine 10.2 mg/dl). Color Doppler showed no flow across the stent. Renal arteriogram showed near total stent occlusion with no collateral flow into the kidney [].\nRamipril was discontinued and he was given two sessions of hemodialysis. A percutaneous balloon dilatation and stent-in-stent (Medtronic racer: 5.0 mm × 18 mm, cobalt chromium) was placed [Figures and ]. On the 2nd day of stent placement his urine out put improved and serum creatinine started to decline and reached a nadir of 1.5 mg/dl on the 7th day.