Hemodynamic and volumetric effects of venodilation with nitroglycerin in chronic mitral regurgitation

To evaluate the potential value of nitrate therapy in patients with chronic mitral regurgitation, the hemodynamic and angiographic effects of intravenous nitroglycerin were studied in 10 such patients. Nitroglycerin infusion, titrated to reduce mean pulmonary artery wedge pressure at least 20%, resulted in a significant reduction in mean blood pressure (from 91 ± 12 to 77 ± 13 mm Hg, p < 0.0001), mean right atrial pressure (12± 6 to 7 ± 4 mm Hg, p < 0.001), left ventricular end-diastolic pressure (22 ± 7 to 13 ± 5 mm Hg, p < 0.0001) and peak V wave of indirect left atrial pressure (34 ± 9 to 20 ± 10 mm Hg, p < 0.001). Changes in systemic vascular resistance (1,986 ± 468 vs 1,582 ± 534 dynes s cm−5) and forward stroke volume (39 ± 14 vs 45 ± 8 ml) were not statistically significant. Angiographic data showed a decrease in both end-diastolic and end-systolic left ventricular volumes (248 ± 51 to 216 ± 54 ml, p = 0.06 and 127 ± 69 to 99 ± 48 ml, p < 0.05, respectively) and an improvement in ejection fraction, from 0.52 ± 0.15 to 0.55 ± 0.15 (p < 0.05). There was no significant change in the group values for mitral regurgitant volume and fraction (from 85 ± 32 to 72 ± 32 ml and 67 ± 10 to 64 ± 5%, respectively). It is concluded that the predominant venodilation of nitrate therapy is associated with a significant improvement in cardiovascular hemodynamics and left ventricular function in patients with severe chronic mitral regurgitation. In most cases, these changes result from the peripheral vascular effects of the drug rather than from a reduction of mitral valve regurgitant volume.