Role of intra-aortic morphine in post conditioning during valvular surgery with low ejection fraction

Abstract

Background

The application of cardioplegia does not completely eradicate myocardial ischemia in cardiac/reperfusion injury due to cardiac arrest. Post conditioning is novel strategy of attaining cardioprotection. Pharmacological post conditioning using a drug as morphine administered before reperfusion would protect the heart against ischemia-reperfusion injury. We investigated whether intra-aortic morphine administration has a post conditioning effect on patients with low ejection fraction (EF) undergoing valve surgery.

Methods

This prospective randomized controlled trial in a single center involved one hundred patients scheduled for elective valve surgery were divided into two groups: the Post conditioning group and the Control group. The Post conditioning group (n = 50) received a dose of morphine (0.1 mg/kg) diluted in 20 ml normal saline, injected via a cardioplegia needle into the aortic root with warm hotshot before aortic cross-clamp removal while the control group (n = 50) received the same volume of saline without morphine. Both groups received antegrade warm blood cardioplegia. To assess results EF, fractional shortening (FS), troponin level, ABG, inotropes, postoperative ventilation time, and length of ICU stay were assessed.

Results

Postoperative EF and FS revealed a statistically significant higher readings in the Post conditioning group. A significant reduction in the troponin levels was recorded in the study group than the control group. Duration of postoperative ventilation and length of ICU stay were statistically lesser in the Post conditioning group.

Conclusions

Morphine administration immediately with warm hotshot was related to improvement in the cardiopulmonary function, less inotropic drug use, and higher left ventricular EF.