Does the use of microplegia significantly improve outcomes in congenital heart surgery

Abstract

Introduction: In cardiac surgery requiring cardiopulmonary bypass myocardial protection is of paramount importance and cardioplegia aims to optimize the ischaemic period. The aim of this study is to compare short-term postoperative outcomes of elective congenital cardiac patients undergoing corrective cardiac surgery using two different cardioplegia solutions. A comparison of clinical and biochemical findings were assessed between two cardiac arresting agents, namely all-blood Microplegia and crystalloid St Thomas’ Hospital II Cardioplegic solution. Methods: Forty-two paediatric patients were prospectively randomised prior to corrective cardiac surgery to two techniques of myocardial protection; group I tepid (28°C) Microplegia (MPS) and group II cold (4°C) St Thomas’ Hospital Cardioplegic Solution II (STS) crystalloid cardioplegia. Perioperative data was prospectively collected. Endpoints included serial measurements of Troponin I, haemoglobin/ haematocrit and lactate; time taken for spontaneous return to normal sinus rhythm; and need for postoperative inotropic support. Results: Surgery resulted in increased immediate post-aortic unclamping myocardial lactate and troponin I levels in both groups, however, significantly lower lactate (2.36 ± 0.76 vs 4.19 ± 1.09 mmol/l, p<0.0001) and troponin I levels (8.18 ± 3.68 vs 22.88 ± 13.39 ng/ml, p<0.0001) were observed in Group I vs Group II. Improved myocardial contractility as measured by quicker spontaneous return to normal sinus rhythm and reduced perioperative requirement for inotropic support as well as a reduced need for blood transfusion was evident in Group I. Conclusion: Microplegia showed significantly less myocardial injury, haemodilution and reduced need for inotropic support in the first 24 hours post congenital cardiac surgery.