Enhancement of myocardial recovery with terminal ‘hot shot’ cardioplegia

Background: Terminal ‘hotshot’ (THS) cardioplegia is a technique that might contribute into myocardial protection in patients undergoing cardiac surgery. Objective: To determine the effect of THS cardioplegia administration in patients undergoing coronary artery bypass grafting (CABG). Methods: A randomized control trial (ACTRN12624001225505) was conducted from 20th December 2023 to 10th February 2024 involving 60 patients admitted from the outpatient department for elective CABG at Faisalabad Institute of Cardiology, Faisalabad, Pakistan. It was a single-blinded study and the patients were randomized into two equal groups, group A (control group) and group B (experiment group). During the surgery performed utilizing a Cardiopulmonary Bypass (CPB) machine, both groups received cold blood cardioplegia to arrest the heart, providing a quiescent field at the start of the grafting process in CABG. In group B patients, 100 ml of THS volume was given to each of the grafted territories via saphenous vein grafts and the rest of the volume from the total of 500 mL was given in the aortic root via the antegrade cardioplegia cannula for maximum myocardial distribution. The levels of Troponin I (TnI) and Creatinine Kinase MB (CK MB) were measured in the blood one hour after regaining sinus rhythm and on 5th postoperative day (POD). Durations of postoperative Inotrope use, intubation, aortic cross-clamp, CPB time, time to regain sinus rhythm, and ICU stay were recorded in both the groups. Data was entered and analyzed using SPSS version 25. A p-value ≤ 0.05 was considered statistically significant. Results: Mean age of the participants was 58.9±7.36 years. The levels of TnI were lower in group B than in group A one hour after regaining sinus rhythm (0.20±0.076 ng/ml and 0.31±0.058 ng/ml respectively, p-value <0.001) as well as on the 5th POD (0.15±0.663 ng/ml and 0.26±0.051 ng/ml respectively, p-values<0.001). CK MB levels were also lower in group B than in group A one hour after regaining sinus rhythm (48.4±25.13 IU/L and 70.5±29.00 IU/L respectively) as well as on the 5th POD (39.2±19.44 IU/L and 71.0±37.08 IU/L respectively, p-values<0.05). Inotropic support was used for a shorter time in group B than in group A (5.9±1.99 hours and 7.0±1.87 hours respectively, p-value=0.031). There were no significant differences in the durations of intubation, ICU stay, cross-clamp time, CPB time, and the time to regain sinus rhythm between the two groups (p-values>0.05). Conclusion: ‘Hot shot’ cardioplegia decreases the release of TnI from the myocardial cells post-cardiac surgery. The inotropic support time is also shortened when THS cardioplegia is used.