Beneficial effects of nitroprusside administration on left ventricular dysfunction and myocardial ischemia in severe aortic stenosis

Although surgical therapy is effective for reducing excessive left ventricular (LV) afterload in valvular aortic stenosis (AS), salutary short-term medical treatment has been lacking. Since we have shown LV systolic pressure (SP) is altered concordant with arterial SP in AS by vasopressors, the present study evaluated efficacy of nitroprusside (NP) on LV function, energetics, and perfusion in 15 severe AS patients. NP infusion (average 33 μg/min) proved beneficial in each: LVSP 192 mm Hg was reduced to 164; arterial SP decrement equaled LVSP change; LV end-diastolic pressure 19 mm Hg declined to 10; cardiac index (2.73 L/min/m²) and heart rate were unaltered; total systemic vascular resistance 1433 dsc ⁵ decreased to 1201; elevated LV stroke work index 92 gm·m/m² was diminished to 74. Simultaneously, LV O₂ consumption fell, LV diastolic flow was unchanged, while subendocardial perfusion increased. Thus cautious NP therapy with careful monitoring provided marked reduction of LV afterload and improved LV function, energetics, and coronary flow distribution.