Perfusion interval and myocardial injury in minimally invasive mitral valve surgery: the modifying role of aortic cross-clamp duration
Chengying Shao, Wenshuai Mao, Lijun Guo, Zhiwei Liu, Xujie Hu, Jue He, Yong Cui, Zhibin HuAbstract
OBJECTIVES
To assess how perfusion interval relates to myocardial injury and whether this is modified by aortic cross-clamp duration in minimally invasive mitral valve surgery.
METHODS
We retrospectively analysed 556 patients receiving blood-enriched modified del Nido cardioplegia. The primary exposure and outcome were longest perfusion interval and base-10 logarithm-transformed peak cardiac troponin I within 48 hours. Analyses included multivariable regression, interaction and subgroup analysis, restricted cubic splines, sensitivity analysis, and logistic regression.
RESULTS
Longer perfusion intervals were initially associated with higher cardiac troponin I (regression coefficient 0.0097, 95% confidence interval 0.0035–0.0159; P = 0.002). This association disappeared after adjustment for factors including aortic cross-clamp time and number of perfusions (regression coefficient -0.0006, 95% confidence interval -0.0109–0.0097; P = 0.913). Aortic cross-clamp time remained independently associated with cardiac troponin I (regression coefficient 0.0099, 95% confidence interval 0.0013–0.0185; P = 0.024). In patients with prolonged aortic cross-clamp time, exploratory analysis suggested a non-linear increase beyond 80 min. In patients with aortic cross-clamp time of 90 min or less, perfusion interval was not clearly associated with peak cardiac troponin I. No significant associations were found with the composite of adverse events.
CONCLUSIONS
The association between perfusion interval and myocardial injury depended on aortic cross-clamp duration. Single-dose blood-enriched modified del Nido cardioplegia appeared adequate when aortic cross-clamp time was 90 min or less. Longer intervals in prolonged procedures may matter, but the 80-minute threshold remains exploratory. These findings support a context-dependent myocardial protection strategy.