Hemodynamic Changes During Off-Pump Coronary Artery Bypass Anastomosis in Patients with Coexisting Mitral Regurgitation: Improvement with Milrinone

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Abstract
We hypothesized that mitral regurgitation (MR) would be exacerbated, cardiac index (CI) decreased, and mean pulmonary artery pressure (MPAP) increased in patients with coexisting MR during off-pump coronary artery bypass (OPCAB) anastomosis, and that milrinone could ameliorate increases in MR that occur during OPCAB anastomosis. Subjects comprised 140 patients scheduled for elective OPCAB divided into three groups: patients without MR (MR(-) group; n = 57), patients with MR (MR(+) group; n = 41), and patients with MR who received milrinone (M+MR(+) group; n = 42). Patients with grade 1+ or 2+ MR were included, whereas those with grade 3+ or 4+ MR were excluded. Hemodynamic variables were measured after the induction of anesthesia and during anastomosis. IV infusion of milrinone (0.5 microg . kg(-1) . min(-1)) started immediately after the induction of anesthesia in the M+MR(+) group. CI was significantly decreased (P < 0.0001), and MPAP and MR were significantly increased (P < 0.001) during left coronary anastomosis in the MR(+) group compared with the MR(-) group. CI was significantly higher (P < 0.001), and neither MPAP nor MR were increased (P < 0.05) during left coronary artery anastomosis in the M+MR(+) group compared to the MR(+) group. In patients with MR, anastomosis of the left coronary artery branches was associated with decreased CI and increased regurgitation and MPAP. In such patients, treatment with milrinone helps to stabilize hemodynamics during anastomosis.