Predicting Blood Pressure Response after Renal Artery Stent Placement

Background: Although technical success of renal artery stenting (RAS) is high, clinical success (improved blood pressure and/or renal function) has been less predictable. Identifying those patients who will respond to RAS may improve overall outcomes and the cost-benefit ratio of the procedure.
Methods: This is a retrospective analysis of a prospectively held database including all patients who have undergone RAS for treatment of renovascular hypertension (HTN) between 2001 and 2007 at Dartmouth-Hitchcock Medical Center. The primary outcome measure of the study was blood pressure improvement or cure as judged by American Heart Association criteria. Serum creatinine was evaluated as a secondary outcome. Changes in outcomes were analyzed over time using Kaplan-Meier life table methodology. Univariate and multivariate regression were performed to indentify factors predictive of the outcome measures.
Results: One hundred and twenty-nine patients underwent RAS for renovascular HTN over the 6-year period. Procedural complications occurred in 7.3% (n=9) of patients. Average length follow-up was 1.5 years. Follow-up data was obtained in 122 patients (95%). There were significant improvements in systolic blood pressure (161 v. 144 mmHg, p<0.001), diastolic blood pressure (80 v. 73 mmHg, p<0.001) and number of anti-hypertensive medications (3.1 v 2.8, p=0.034) across the sample. By univariate analysis, the only factor associated with blood pressure improvement was pre-procedural creatinine level. When patients were stratified by creatinine (Figure), sustained blood pressure improvement was noted only in those patients with normal renal function prior to RAS (HR 1.6; 95% CI 1.1 to 2.4). At last follow-up mean serum creatinine was statistically worsened across the sample (1.5 to 1.9, p=0.023).
Conclusion: Sustained clinical improvement following RAS for renovascular HTN is limited. Those patients without pre-existing end-organ damage appear to be the only group to maintain improvement at 2-years.