ObjectiveTo retrospectively compare and analyze the effect of myocardial protection between histidinetryptophane-ketoglutarate (HTK) and 4:1 blood cardioplegia in patients with complex coronary artery disease and left ventricular dysfunction. MethodsFrom January 2003 to July 2013, 2132 patients underwent isolated coronary artery bypass grafting (CABG) in our institution. Among them, 227 patients with complex coronary artery disease (left main or triple vessel disease) and left ventricular dysfunction (ejection fraction ≤ 50%) were included in this study. According to the category of cardioplegia utilized in the operations, the patients were divided into two groups: a HTK group (85 males and 4 females, n=89) and a blood cardioplegia group (113 males and 25 females, n=138). The average age was 62.78±9.30 years in the HTK group and 62.74±9.07 years in the blood cardioplegia group. The effect of myocardial protection between two groups was compared. ResultsAccording to the pre-operational data of these two groups, there was no significant difference identified in terms of basic characteristics and risk factors, even though more female patients were found in the blood cardiophegia group and more patients with renal dysfunction were found in the HTK group. In addition, the patients in the HTK group had more distal anastomosis, longer cardiopulmonary time and cross clamping time than those in the blood cardiophegia group. Based on the results measured by those primary assessment criteria,there was no significant difference being found between these two groups. However, on those secondary assessment criteria the pulmonary pressure and inotropic support after reperfusion were significantly higher in the HTK group than its counterpart. ConclusionFor patients with complex coronary artery disease and left ventricular dysfunction, HTK solution and blood cardioplegia provide similar effective myocardial protection. HTK doesn't significantly increase postoperative adverse cardiovascular events under the circumstance of longer ischemic time.