Renal artery stenosis (RAS) patients who undergo percutaneous renal revascularization in addition to medical therapy could require less antihypertensive medications; however, this was not true for improvements in serum creatinine or clinical outcomes when compared with medical management over a mean 29-month follow-up, according to a study published in this month's American Heart Journal.
RAS is commonly found in patients diagnosed with atherosclerosis in other vascular distributions and can cause secondary hypertension and renal insufficiency and has been associated with cardiovascular morbidity. “Although surgical revascularization has not been shown to be superior to medical management in patients with significant RAS and resistant hypertension, it is unclear if this is true for percutaneous revascularization as well,” the authors wrote.
Dharam J. Kumbhani, MD, of the Cleveland Clinic in Cleveland, and colleagues conducted a meta-analysis that included six randomized controlled trials collectively enrolling 1,208 renal artery stenosis patients to evaluate whether there was benefit of performing percutaneous revascularization compared with medical management alone.
Inclusion criteria for the analysis included patients with RAS who were assigned to receive percutaneous revascularization with balloon angioplasty with or without stenting, in addition to medical therapy versus medical therapy alone. Of the 1,208 patients enrolled into the six studies, 599 were randomized to percutaneous revascularization and 609 were randomized to medical management.
The researchers reported that the mean number of antihypertensive medications at baseline was 2.74 and 2.76 in the percutaneous intervention and medical therapy arms, respectively. Additionally, there were no significant differences in the changes of systolic blood pressure, diastolic blood pressure or serum creatinine from baseline between the percutaneous intervention and medical therapy arms.
At the end of follow-up, the researchers reported a decrease in the mean number of antihypertensive medications in the percutaneous intervention arm compared with the medical therapy arm. This could point to a blood pressure lowering benefit from revascularization.
Kumbhani et al reported that the overall rates of all-cause mortality were 14.9 percent in the percutaneous intervention arm and 15.4 percent in the medical therapy; likewise, rates of congestive heart failure were 9.8 percent and 12.2 percent, respectively.
Incidence of stroke was 4.4 percent in the percutaneous intervention arm and 5.1 percent in the medical therapy arm, while the rates of renal functioning worsened and was reported to be 11.5 percent in the percutaneous intervention arm and 12.6 percent in the medical therapy arm.
Lastly, the rates of periprocedural complications ranged from 7.1 percent to 31.3 percent in all studies. These rates included four deaths and 12 renal artery or kidney perforations or dissections.
“Renal artery stenosis is often suspected in patients with unexplained impairment in renal function, especially in hypertensive patients,” the researchers said. “It thus seems counterintuitive that treating RAS with stenting, and thus improving renal blood flow, is not associated with an improvement in renal function or clinical outcomes.”
The authors noted that this could be due to in part to a high amount of overlap between risk factors associated with aortorenal vascular disease and parenchymal kidney disease. And because diabetes mellitus, smoking, dyslipidemia and hypertension have been shown to be independently associated with renal injury, revascularization of the renal artery may fail to improve kidney function that is mediated by microvascular kidney disease rather than macrovascular atherosclerotic RAS.
“From a technical standpoint, the procedure of stenting is not perfect; there could be distal embolization, and the use of contrast that may lead to some renal compromise,” the researchers noted. “It is thus unknown if aggressive control of blood pressure in the post stenting part and close surveillance for restenosis would change outcomes after percutaneous revascularization.
“The results of our meta-analysis of six randomized controlled trials suggest that, as compared with medical management, percutaneous renal revascularization in addition to medical therapy in patients with RAS and resistant hypertension and/or chronic renal insufficiency may result in a marginal