Aspirin injection test to predict angioplasty outcome in unilateral renovascular hypertension: preliminary report.

We examined the usefulness of aspirin DL-lysine for prediction of the outcome of renal artery angioplasty in renovascular hypertension. The study was carried out in eight hypertensive patients with unilateral renal artery stenosis: six were free from azotemia and two had slight azotemia. Before and 30 min after an intravenous injection of aspirin DL-lysine (18 mg/kg), renal venous and abdominal aortic plasma was sampled and assayed for prostaglandin E2 and plasma renin activity. Blood pressure and heart rate were serially measured at this time. Renal angioplasty was later performed and was technically successful in all patients. In the six patients without azotemia, aspirin inhibited renal prostaglandin E2 synthesis and suppressed renin release from the ischemic kidney, resulting in lowered blood pressure. Renal angioplasty caused plasma renin activity to become normal and lowered high blood pressure. The reduction in blood pressure by angioplasty was correlated with the responses of blood pressure and renin release to aspirin. However, in the two patients with azotemia, aspirin neither suppressed renin release nor lowered blood pressure. Their hypertension was not reduced by the angioplasty. These results indicate that an aspirin injection test could be useful for prediction of the outcome of angioplasty in unilateral renovascular hypertension.