Systemic and regional hemodynamic effects of captopril and milrinone administered alone and concomitantly in patients with heart failure

The effects of milrinone and captopril on ventricular performance, renal blood flow, and femoral vein oxygen content were compared in 11 patients with severe chronic heart failure. The increase in stroke volume index was greater with milrinone than with captopril (28 ± 7 vs 24 ± 7 ml/m²; p < .05), while pulmonary capillary wedge pressures fell similarly (19 ± 10 vs 21 ± 7 mm Hg). Mean systemic arterial pressure decreased significantly from 84 ± 10 to 73 ± 11 mm Hg (p < .05) with captopril but did not with milrinone. Neither drug changed heart rate significantly. Although milrinone produced a greater improvement in ventricular performance than captopril, renal blood flow increased similarly with both drugs from 289 ± 78 to 417 ± 111 ml/min (p < .05) and from 278 ± 77 to 441 ± 115 ml/min (p < .05), respectively. Femoral vein oxygen content was increased by milrinone from 7.9 ± 2.6 to 9.8 ± 3.0 ml/100 ml (p < .05) and was not changed by captopril. In seven additional patients, intravenous milrinone, administered at the peak effect of captopril, further augmented stroke volume index from 24 ± 6 to 32 ± 6 ml/m² (p < .05) and tended to reduce pulmonary capillary wedge pressure further from 20 ± 8 to 18 ± 9 mm Hg (p = NS). The addition of intravenous milrinone to captopril did not reduce mean systemic arterial pressure (71 ± 8 vs 71 ± 8 mm Hg) or significantly increase heart rate (89 ± 17 vs 92 ± 18 beats/min) when compared with captopril alone. Although renal blood flow was not further increased by the addition of intravenous milrinone to captopril, femoral vein oxygen content increased from 6.8 ± 1.9 to 9.9 ± 1.8 ml/100 ml (p < .05). Thus simultaneous administration of captopril and milrinone has synergistic effect on cardiac performance and complementary effects on the peripheral circulation.