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Vasodilator Therapy for Selected Patients with Aortic Stenosis

This study uncovered an unexpected potential addition to the armamentarium for treating a subgroup of patients who typically have a grim prognosis.

Given the urgent needs of patients with severe aortic stenosis and heart failure, Cleveland Clinic investigators decided to challenge the largely untested conventional wisdom that the potent vasodilator nitroprusside should be contraindicated in these patients. Criteria for enrollment in this prospective study were admission for heart failure to the ICU, LV ejection fraction 35%, aortic-valve area 1 cm², and depressed cardiac index (2.2 L/min/m²). Patients who required inotropic support or had a mean arterial pressure (MAP) <60 mm Hg were excluded.

Over 21 months, the investigators enrolled 25 patients (mean age, 73; 64% male; mean aortic-valve pressure gradient, 39 mm Hg; mean peak AVPG, 65 mm Hg; mean aortic-valve area, 0.6 cm²). After baseline hemodynamic measurements, subjects were given intravenous nitroprusside (target MAP, 60 to 70 mm Hg).

Mean baseline cardiac index (1.60 L/min/m²) increased significantly to 2.22 at 6 hours and to 2.52 L/min/m² at 24 hours, with no patient showing a decrease. Mean systemic vascular resistance, pulmonary vascular resistance, and pulmonary artery pressure all decreased significantly by 24 hours. All 25 patients tolerated nitroprusside infusion well. Fourteen patients underwent open-heart surgery, 1 underwent balloon valvuloplasty, 6 were converted to medical therapy, and 4 others (plus 1 of the surgery patients) died in the hospital. The 30-day survival rate was 76%.

Comment: This small, carefully performed study appears to add an important bridging therapy to our limited armamentarium for treating patients with severe aortic stenosis and decompensated heart failure. Nitroprusside infusion rapidly improved hemodynamic parameters without any apparent adverse effects. The results suggest that the fixed aortic valve is not the only source of afterload imposed on a failing ventricle. The prognosis for these patients is so grim that any new therapy is welcome. Nevertheless, if this approach is to be used widely before confirmation elsewhere, close monitoring with careful attention to the patient's evolving clinical condition is imperative.

— Harlan M. Krumholz, MD, SM

Published in Journal Watch Cardiology June 6, 2003

Citation(s):

Khot UN et al. Nitroprusside in critically ill patients with left ventricular dysfunction and aortic stenosis. N Engl J Med 2003 May 1; 348:1756-63.

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