Predicting blood pressure improvement in hypertensive patients after renal artery stent placement: Renal fractional flow reserve

Background: Renal stent placement improves or cures hypertension in only 60-70% of patients with renal artery stenosis (RAS) and uncontrolled hypertension. There is a need to better identify patients who are likely to respond to percutaneous renal revascularization. We investigated whether an abnormal renal fractional flow reserve (FFR) would predict blood pressure improvement in patients undergoing renal artery stent placement. Methods: We prospectively enrolled 17 patients with unilateral RAS and medically refractory hypertension (BP > 140/90 mm Hg). Renal FFR was measured at maximal hyperemia induced by papaverine followed by renal stent placement. Blood pressure improvement was defined as a blood pressure of <= 140/90 mm Hg or an absolute decrease in diastolic blood pressure by 15 mm Hg on the same or less number of medications. Patients not meeting the above criteria were nonresponders. Results: Renal stent placement was successful in all patients. The average follow-up was 10 2 months. In patients with an abnormal renal FFR (<0.80) blood pressure improved at 90 days in 86% compared with 30% in the normal renal FFR group (P = 0.04). Translesional pressure gradients (resting, peak, or hyperemic) alone failed to differentiate blood pressure responders from nonresponders. Conclusions: Renal FFR is a promising tool to identify patients likely to benefit following renal stent placement. This finding was independent of translesional pressure gradients, which did not predict blood pressure improvement. The ability to segregate patients with RAS and coexisting hypertension from those with renovascular hypertension may help clinicians select patients most likely to benefit from revascularization. (C) 2007 Wiley-Liss, Inc.