Comparison of the myocardial protection efficacy between Del Nido cardioplegia and HTK cardioplegia in adult cardiac valve surgery

Background With the advancement of cardiopulmonary bypass technology, several cardioplegia solutions have been introduced, including del Nido cardioplegia (DN) and histidine-tryptophan-ketoglutarate (HTK) solutions. However, the cardioplegia solution with the most effective myocardial protection in patients undergoing cardiac valve surgery remains controversial. Therefore, we aimed to evaluate the efficacy of myocardial protection using DN cardioplegia solution versus HTK solution in patients who underwent adult cardiac valve surgery by measuring left ventricular strain using two-dimensional speckle-tracking echocardiography (2D-STE) combined with monitoring myocardial enzymes. Methods The study population consisted of 99 patients who underwent cardiac valve surgery and were transferred to the intensive care unit postoperatively at Nanjing First Hospital between March 2022 and June 2023. The patients were divided into groups based on the type of cardioplegia solution used intraoperatively: the HTK and Del Nido groups. Using conventional transthoracic echocardiography, we measured left ventricular end-diastolic diameter, left ventricular end-systolic diameter, stroke volume, left ventricular ejection fraction, left atrial diameter, and left ventricular outflow tract velocity time integral (VTI). Left ventricular global longitudinal strain (LV-GLS) was measured preoperatively and on postoperative days 1, 3, and 7 using the 2D-STE technique. The left ventricular longitudinal strain values were recorded in the apical long-axis, two-chamber, and four-chamber views (LAX-GLS, A2C-GLS, A4C-GLS). Serum levels of Troponin I (TNI) and heart-type fatty acid-binding protein (H-FABP) were monitored at each time point. Baseline characteristics, surgical details, biochemical indicators, and postoperative vasopressor use data were collected for both groups. Differences in conventional echocardiography, left ventricular strain, and myocardial enzyme markers between the two groups were compared. Perioperative composite adverse events, including malignant arrhythmias, sudden cardiac arrest, respiratory failure, low cardiac output syndrome, delirium, and mortality, were recorded in both groups. Results Myocardial injury is reflected by changes in cardiac enzyme levels and left ventricular strain measurements in patients undergoing valve surgery procedures. TNI and H-FABP concentrations in the two groups reached their peaks on the first day after surgery, then showed a gradual downtrend throughout the first week. Compared to the HTK group, the concentration of serum H-FABP at T1 was lower in the Del Nido group (28.42 ± 10.69 vs 20.31 ± 11.20 pg/mL, p = 0.03), but there were no significant differences between the two groups at T0, T3, and T7. The serum cardiac troponin I (TNI) concentrations were comparable between the HTK group and the Del Nido group. Similarly, no significant differences were observed between the two groups for VTI, LV-GLS, LAX-GLS, A4C-GLS, or A2C-GLS. However, LV-GLS values were significantly lower at all postoperative time points compared to preoperative levels in both groups, indicating impaired left ventricular systolic function postoperatively. The longitudinal strain values of LAX and A4C in the HTK group patients returned to preoperative levels on the seventh day postoperatively (−11.26 ± 4.61 vs −14.51 ± 5.61, p > 0.05; −10.41 ± 5.14 vs −13.29 ± 5.86, p > 0.05, respectively). Conversely, in the Del Nido group, the longitudinal strain values remained decreased compared to baseline on postoperative day 7. Conclusions Left ventricular strain function experiences a decline in the week immediately following cardiac valve surgery. The accelerated recovery of LAX-GLS and A4C-GLS associated with HTK cardioplegia supports its reliability as a myocardial protectant during extended ischemia.