Elevated Brain Natriuretic Peptide Predicts Blood Pressure Response After Stent Revascularization in Patients With Renal Artery Stenosis

Abstract

Background-A significant number (20% to 40%) of hypertensive patients with renal artery stenosis will not have blood pressure improvement after successful percutaneous revascularization. Identifying a group of patients with refractory hypertension and renal artery stenosis who are likely to respond to renal stent placement would be beneficial. Methods and Results-Brain natriuretic peptide (BNP) was measured in 27 patients with refractory hypertension and significant renal artery stenosis before and after successful renal artery stent placement. This neuropeptide was elevated (median, 187 pg/mL; 25th to 75th percentiles, 89 to 306 pg/mL) before stent placement and fell within 24 hours of the successful stent procedure (96 pg/mL; 25th to 75th percentiles, 61 to 182 pg/mL; Pϭ0.002), remaining low (85 pg/mL; 25th to 75th percentiles, 43 to 171 pg/mL) at follow-up. Clinical improvement in hypertension was observed in the patients with a baseline BNP Ͼ80 pg/mL (nϭ22) in 17 patients (77%) compared with 0% of the patients with a baseline BNP Յ80 pg/mL (nϭ5) (Pϭ0.001). After correction for glomerular filtration rate, BNP was strongly correlated with improvement in hypertension. Conclusions-BNP is increased in patients with severe renal artery stenosis and decreases after successful stent revascularization. In addition, an elevated baseline BNP level of Ͼ80 pg/mL appears to be a good predictor of a blood pressure response after successful stent revascularization. (Circulation. 2005;111:328-333.)

Catheter-Based Therapy for Atherosclerotic Renal Artery Stenosis

“…When the poststent BNP fell by Յ30%, only 1 patient (10%), had improved blood pressure control (PϽ0.001) ( Figure 5). 46 Our preliminary data suggest that BNP is increased in patients with refractory hypertension and renal artery stenosis and that this peptide may be useful in predicting which patients will clinically improve their blood pressure after successful renal revascularization. An elevated baseline BNP Ͼ80 pg/mL strongly correlated with hypertension improvement after 3.5 months of follow-up.…”

“…Preliminary data suggest that the use of physiological lesion assessment (renal FFR) and/or biomarkers (BNP) can enhance lesion selection and result in improved clinical response rates. 40,46 Further studies are needed to establish their clinical role.…”

“…44,45 We prospectively studied 27 patients with uncontrolled hypertension who had visually estimated significant atherosclerotic renal artery stenosis (Ն70% diameter stenosis) by contrast angiography. 46 Patients with other medical conditions associated with elevated BNP levels (congestive heart failure, acute coronary syndromes, and renal failure) were excluded. Procedure success, defined as a Յ30% residual diameter stenosis without a serious complication after renal stent placement, was obtained in all of the patients.…”

Is Renal Artery Stenting the Correct Treatmentof Renal Artery Stenosis?

“…Recent work suggests a relationship between brain natriuretic peptide and RAS, with high brain natriuretic peptide levels (Ͼ80 pg/mL) associated with better outcomes after renal artery intervention. 55 Angiotensin II, endothelin, or an insulin-like growth factor, and sympathetic activation all may be involved in the process of ventricular thickening and stiffening. 46 -49,53 Angiotensin has been implicated in the mechanism of cardiac hypertrophy and is known to induce protein synthesis in myocardial cells, 50 even when the mean arterial pressure is lowered.…”

“…Previous investigators have suggested that the response to revascularization may be predicted by the presence of microvascular dysfunction measured with the renal resistive index 100 or by the presence of neurohumoral activation. 55 Fundamentally, though, each of these observations is limited by the absence of a contrasting group of medically managed patients who are concurrent and carefully controlled. Thus, all such observations suggest but are unable to establish the relative benefit of revascularization or the true value of the baseline test strategy to predict outcome with differing treatments.…”