Keeping the heart empty and beating: an alternative technique to preserve hypertrophied hearts during valvular surgery.

Shangdian Liu,Lulu Li,Pengfei Liu,Hongyu Liu,Zonghong Liu

doi:10.1186/s13019-015-0273-2

Abstract

IntroductionTo determine whether keeping the heart empty and beating is an effective technique to preserve hypertrophied pig hearts, and to investigate the underlying mechanism.MethodsTen Bama Miniature pigs with hypertrophied hearts were divided into 2 groups (n = 5 in each group). One group underwent normothermic normokalemic simultaneous perfusion (NNSP). The other group was subjected to normothermic hypermokalemic simultaneous perfusion (NHSP) and used as controls. Cardiac contractive function, myocardial energy metabolism and myocardial perfusion were assessed using magnetic resonance imaging. Western blot analysis was carried out to determine the expression of Troponin I (cTnI), Troponin T (cTnT), SM-MHC, Casapase-3 and PARP4. TUNEL assay was used to detect apoptotic cardiomyocytes.ResultsKeeping the heart empty and beating with NNSP improved the preservation of contractile function in comparison with cardioplegic arrest using NHSP. No significant differences existed in the effects of NNSP and NHSP in maintaining myocardial energy metabolism. 13 % perfusion defects areas were found in one heart in the NHSP group, whereas none was found in all other hearts in both groups. The expressions of cTnI, cTnT, Casapase-3 and PARP4 in NHSP group were abundantly increased compared to NNSP group as measured by Western blotting. Conversely, the expression of SM-MHC in NHSP group was reduced compared with NNSP group. The number of TUNEL positive nuclei per mm2 area was significantly increased in NHSP group compared with NNSP group.ConclusionsKeeping the heart beating with NNSP is an alternative technique to preserve hypertrophied hearts during valvular surgery.

Highlights

To determine whether keeping the heart empty and beating is an effective technique to preserve hypertrophied pig hearts, and to investigate the underlying mechanism
Effect of normokalemic simultaneous perfusion (NNSP) and normothermic hypermokalemic simultaneous perfusion (NHSP) on contractile function After undergoing NNSP and NHSP, Left ventricular end-systolic volume and left ventricular end-diastolic volume of both groups were measured by the cine MR imaging
The published preliminary clinical experience suggests that keeping the heart empty and beating during valve surgery is conducive to high-risk patients [21, 22]

Summary

Introduction

To determine whether keeping the heart empty and beating is an effective technique to preserve hypertrophied pig hearts, and to investigate the underlying mechanism. For safe and effective valve surgery, adequate myocardial protection is considered to be an important aspect. Hypothermic cardioplegia techniques were applied and well accepted to induce myocardial protective effects by reducing oxygen consumption in the initial stage [2]. It is known to be associated with a significant enlargement of the myocardial interstitial compartment and a decrease in the density of the capillaries and mitochondria [12,13,14]. These pathologic changes have established the histologic foundation for severe and compromised myocardial perfusion and energy metabolism.

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Discussion

Conclusion