Aortic Cross-Clamp Duration in CABG: A Critical Determinant of Myocardial Injury and Early Outcomes

Abstract

Coronary artery bypass grafting (CABG) remains one of the most commonly performed cardiac surgical procedures worldwide, with continuous advancements improving operative safety and patient outcomes. Despite these developments, perioperative myocardial injury continues to represent a significant clinical challenge. Among the various intraoperative determinants, aortic cross-clamp duration has consistently been identified as an important factor influencing myocardial ischemia and postoperative recovery [1]. The pathophysiological basis linking cross-clamp duration to myocardial injury is well established. During aortic cross-clamping, coronary blood flow is interrupted, rendering the myocardium dependent on protective strategies such as cardioplegia and hypothermia to limit ischemic damage. While these techniques have substantially improved myocardial preservation, their protective capacity is not absolute, particularly when ischemic duration is prolonged [2]. Building on this biological rationale, the present study demonstrates a significant association between prolonged cross-clamp time and elevated postoperative Troponin I levels. Elevated troponin levels were further associated with adverse early clinical outcomes, including prolonged ICU stay, extended duration of mechanical ventilation, and increased requirement for defibrillation [3,4]. Troponin I is not only a sensitive biomarker of myocardial injury but also an established predictor of early postoperative morbidity [5]. These findings reinforce the consistently reported relationship between ischemic time and myocardial injury, supporting the concept that longer cross-clamp durations contribute to greater myocardial damage. At the same time, the variability in clinical outcomes observed across studies suggests that cross-clamp time should not be interpreted in isolation but rather within the broader context of perioperative care. Strategies aimed at reducing cross-clamp duration include meticulous surgical planning, improved technical efficiency, and optimization of myocardial protection protocols. In selected patients, alternative approaches such as off-pump CABG may further reduce ischemic exposure [6,7]. Additionally, troponin-guided risk stratification offers a practical framework for identifying high-risk patients who may benefit from intensified postoperative monitoring, although optimal thresholds for defining perioperative myocardial infarction remain an area of ongoing debate [8]. In conclusion, aortic cross-clamp duration remains a modifiable and clinically relevant determinant of myocardial injury in CABG. While the longstanding principle that “time is myocardium” retains important clinical relevance, it does not fully capture the complexity of perioperative myocardial protection. The impact of ischemic time is intricately influenced by the quality of myocardial protection, surgical expertise, and patient-specific factors [9]. The present study underscores the need for a balanced perspective [10]—one that recognizes the importance of minimizing ischemic time while acknowledging that optimal outcomes are achieved through the integration of time efficiency, surgical precision, and comprehensive perioperative management [11]. References Swinkels BM, Ten Berg JM, Kelder JC, Vermeulen FE, Van Boven WJ, de Mol BA. Effect of aortic cross-clamp time on late survival after isolated aortic valve replacement. Interact Cardiovasc Thorac Surg. 2021;32(2):222-8. DOI: 10.1093/icvts/ivaa244 Ruggieri VG, Bounader K, Verhoye JP, Onorati F, Rubino AS, Gatti G, et al. Prognostic Impact of Prolonged Cross-Clamp Time in Coronary Artery Bypass Grafting. Heart Lung Circ. 2018;27(12):1476-82. 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