# Effect of Postconditioning With Intralipid in Patients Undergoing Off-Pump Coronary Artery Bypass Surgery: A Randomized Controlled Trial

## TL;DR

This study tested if Intralipid helps protect the heart during off-pump heart surgery but found no significant benefit.

## Contribution

The study is the first to investigate Intralipid's postconditioning role in off-pump coronary artery bypass surgery.

## Key findings

- Intralipid did not significantly reduce cardiac troponin I levels compared to the control group.
- Postoperative lipid profile, renal, and liver function were unaffected by Intralipid administration.
- No cardioprotective effects of Intralipid were observed in this surgical setting.

## Abstract

Background: Off-pump coronary artery bypass (OPCAB) surgery is an alternative to conventional on-pump coronary artery bypass surgery for cardiac revascularization. It offers several advantages, including reduced mortality, decreased morbidity, and faster recovery. However, maintaining optimal myocardial function during OPCAB remains a challenge due to ischemia-reperfusion injury. Intralipid (IL), a fat emulsion used for parenteral nutrition, has shown potential cardioprotective effects. While the literature has elucidated IL's role as a preconditioning agent in OPCAB and a postconditioning agent in on-pump cardiac surgeries, its postconditioning role in OPCAB remains unexplored. This study aims to evaluate the postconditioning effects of IL in OPCAB surgery by measuring cardiac troponin I levels, hypothesizing that IL would reduce myocardial injury.

Methodology: Forty patients scheduled for elective OPCAB were randomly assigned to the IL group (L group) (n = 20) or the Control group (C group) (n=20) using a computer-generated randomization list. Group allocation was concealed in sequentially numbered opaque sealed envelopes. The IL group received a 20% IL infusion at 2 mL/kg (based on previous studies demonstrating cardioprotective effects at this dosage) immediately after revascularization, while the C group received an equivalent volume of normal saline. Cardiac troponin I (cTnI) levels were assessed preoperatively and at 6, 24, 48, and 72 hours postoperatively. Additionally, hemodynamic parameters during infusion, and various intraoperative and postoperative parameters (inotrope use, ventilatory hours, duration of intensive care unit stay, duration of hospital stay, postoperative left ventricular ejection fraction, postoperative lipid profile, renal and liver function tests) were evaluated.

Results: The results revealed no significant difference in cTnI levels between the intralipid and control groups at any postoperative time point. Postoperative lipid profile, as well as renal and liver function, remained unaffected in all patients.

Conclusions: As evidenced by comparable postoperative cardiac enzyme levels between the intralipid and control groups, we did not find a postconditioning role of IL in OPCAB surgery, suggesting that IL may not provide cardioprotection in this setting. The authors propose a further investigation into alternative administration protocols (like varying doses and administration timings of IL) to elucidate its potential impact as a postconditioning agent in OPCAB.