Oral hydralazine acutely increased coronary blood flow from 144 to 218 ml/min and decreased coronary vascular resistance from 0.55 to 0.36 mm Hg/ml/min in nonischemic heart failure (p<0.01).
Does oral hydralazine improve coronary blood flow and myocardial energetics in patients with chronic nonischemic congestive heart failure?
In patients with severe nonischemic heart failure, acute administration of oral hydralazine significantly increases coronary blood flow and decreases coronary vascular resistance, improving the myocardial oxygen supply-demand ratio despite increased oxygen consumption.
Absolute Event Rate: 218% vs 144%
p-value: p=<0.01
The acute effects of oral hydralazine, 1 mg/kg, on coronary vascular resistance, coronary blood flow (estimated using the coronary sinus thermodilution technique), and myocardial oxygen consumption were evaluated in 10 patients with chronic (New York Heart Association class III and IV) nonischemic congestive heart failure. Central hemodynamic responses demonstrated a modest decrease in mean arterial pressure, pulmonary capillary wedge pressure and systemic vascular resistance (12%, 15% and 29%, respectively), while the cardiac index increased from 2.3 +/- 0.1 to 3.1 +/- 0.3 and left ventricular stroke work index from 24 +/- 3.7 to 28 +/- 3.4 (p less than 0.01). Heart rate and diastolic filling time did not change. Coronary blood flow increased approximately 50%, from 144 +/- 17 to 218 +/- 30 ml/min, and coronary vascular resistance decreased from 0.55 +/- 0.09 to 0.36 +/- 0.08 mm Hg/ml/min (both p less than 0.01). Oral hydralazine increased myocardial oxygen consumption by 33%, from 15 +/- 1.6 to 20 +/- 2.7 ml/min. Despite this moderate augmentation in myocardial oxygen consumption, the arterial-coronary sinus oxygen difference decreased from 104 +/- 6.2 to 94 +/- 7.5 and the myocardial oxygen extraction ratio decreased from 71% to 64% (both p less than 0.05). The ratio of coronary vascular resistance to systemic vascular resistance decreased with hydralazine therapy, while coronary blood flow increased from 3.5% to 4.3 % of total cardiac output. In this group of patients with nonischemic cardiomyopathy, hydralazine had a favorable effect on the coronary circulation and improved the critical myocardial oxygen supply-demand ratio.
Magorien et al. (Mon,) conducted a other in chronic nonischemic congestive heart failure (n=10). oral hydralazine vs. baseline was evaluated on coronary blood flow (p=<0.01). Oral hydralazine acutely increased coronary blood flow from 144 to 218 ml/min and decreased coronary vascular resistance from 0.55 to 0.36 mm Hg/ml/min in nonischemic heart failure (p<0.01).