Operation for acute postinfarction mitral insufficiency using continuous oxygenated blood cardioplegia

Patients with acute-onset mitral insufficiency and cardiogenic shock after myocardial infarction have a high incidence of operative death and morbidity. Patients with ventricular dysfunction, myocardial ischemia, and limited cardiac reserve undergoing an urgent operation represent a challenge to modern methods of myocardial protection. To improve results of operation a new technique was devised with continuous infusion of cold oxygenated blood cardioplegia during the entire crossclamp period. Between 1984 and 1988, 19 consecutive patients with severe mitral regurgitation and cadiogenic shock (systolic blood pressure less than 60 mm Hg) after myocardial infarction underwent urgent myocardial revascular izaction, mitral valve replacement, or both. Left ventricular ejection fraction was less than 40% in 16 of 19 patients. All patients had sufffered myocardial infarction within 4 weeks of operation and underwent an urgent operation within 24 hours of the onset of hemodynamic compromise. Severe three-vessel coronary artery disease was present in 16 of the 19 patients. A continuous infusion of blood cardiopleigia was instituted at aortic crossclamping and continued throughout the cross-clamp period. Infusion of continuous blood cardioplegia was also instituted through each completed distal vein graft. Myocardial septal and left ventricular apical temperatures were maintained at 10⁴ ± 2°c throughout the cross-clamp period. There were two in-hospital deaths (mortality, 10.5%) and low output syndrome was present in 10 patients (53%). At a mean follow-up of 2.5 yean, there was one late death and 14 of the 16 remaining patients were in New York Heart Association functional class I or II. Continuous infusion of cold blood cardioplegia may be technically more demanding than traditional intermittent infusion; however, it may offer improved myocardial protection in high-risk patients undergoing an urgent operation. Additional randomized controlled clinical trials are necessary to allow improvement in mortality and morbidity in this complication of myocardial infarction.