Clinical results of different myocardial protection techniques in aortic stenosis

Abstract

Background: Hypertrophied myocardium is especially vulnerable to ischemic injury. This study aimed to compare the early and late clinical outcomes of three different methods of myocardial protection in patients with aortic stenosis. Methods: This retrospective study included 225 consecutive patients (mean age, 65±10 years; 123 males) with severe aortic stenosis who underwent aortic valve replacement. Patients were excluded if they had coronary artery disease, an ejection fraction <50%, more than mild aortic regurgitation, or endocarditis. The patients were divided into three groups: group A, which was treated with antegrade and retrograde cold blood cardioplegia; group B, which was treated with antegrade crystalloid cardioplegia using histidine-tryptophan-ketoglutarate (HTK) solution; and group C, treated with retrograde cold blood cardioplegia. Results: Group A contained 70 patients (31.1%), group B contained 74 patients (32.9%), and group C contained 81 patients (36%). The three groups showed significant differences with regard to the proportion of patients with a New York Heart Association functional classification ≥III (p=0.035), N-terminal pro-brain natriuretic peptide levels (p=0.042), ejection fraction (p=0.035), left ventricular dimensions (p<0.001), left ventricular mass index (p<0.001), and right ventricular systolic pressure (p <0.001). Differences in cardiopulmonary bypass time (p=0.532) and aortic cross-clamp time (p=0.48) among the three groups were not statistically significant. During postoperative recovery, no significant differences were found regarding the use of inotropes (p=0.328), mechanical support (n=0), arrhythmias (atrial fibrillation, p=0.347; non-sustained ventricular tachycardia, p=0.1), and ventilator support time (p=0.162). No operative mortality occurred. Similarly, no significant differences were found in long-term outcomes. Conclusion: Although the three groups showed some significant differences with regard to patient characteristics, both antegrade crystalloid cardioplegia with HTK solution and retrograde cold blood cardioplegia led to early and late clinical results similar to those achieved with combined antegrade and retrograde cold blood cardioplegia.