A narrative review of acute type A aortic dissection management through a vascular surgeon's perspective

OBJECTIVE Acute Type A aortic dissection (ATAAD) is a morbid condition with a mortality rate of 23.8% that requires emergent diagnosis and surgical treatment. End-organ ischemia has long been reported as a complication of aortic dissection, with mesenteric malperfusion demonstrating a 63.2% mortality rate in ATAAD. In this paper, we review predictive variables of in-hospital mortality and risk-scoring systems and propose a definition of complicated ATAAD based on preoperative patient assessment. Within this classification, we suggest a new definition of cardiac-complicated and vascular-complicated ATAAD presentations based on clinical, laboratory, and radiographic findings to better justify which operation the patient should be offered first. METHODS We present a narrative review of papers published between 2000 to 2021 that demonstrate statistically significant risk factors of postoperative mortality in ATAAD repair. An initial MEDLINE search was performed using the terms "acute Type A aortic dissection," "complications," "malperfusion," and "risk." Full-text articles describing registry data and risk-stratification of patients with ATAAD undergoing surgical repair were reviewed for inclusion. Reference lists were similarly evaluated. Two authors selected articles together based on the proposed risk stratification and discussion of malperfusion in mortality prediction. RESULTS 12 articles were included in this review. The authors analyze significant predictors of in-hospital mortality, along with describing and validating original risk-stratification systems. Patients presenting with hemodynamic instability should be recognized as having cardiac-complicated ATAAD, which generally warrants prompt proximal aortic repair. Hemodynamic instability is due to associated aortic insufficiency, coronary malperfusion, cardiac tamponade, aortic rupture, and/or neurological malperfusion. Meanwhile, mesenteric malperfusion with hemodynamic stability is defined as vascular-complicated ATAAD, which presents clinically as malperfusion syndrome. The extent of mesenteric malperfusion can be evaluated through visualization of branch vessel obstruction, lactate levels (<2, 2 to 5, 5 to 8, >8 mmol/L), and base deficit (0 to –5, –5 to –7, –7 to –10, ≥–10). Severe mesenteric malperfusion warrants consideration of endovascular treatment before central aortic repair. CONCLUSIONS Our described classification of cardiac- and vascular-complicated ATAAD requires validation through single- and multi-center retrospective studies. With validation, our efforts may provide guidance in the systematic preoperative assessment of ATAAD patients to determine the appropriate initial intervention to reduce morbidity and mortality.