Role of proximal and distal tear size ratio in hemodynamic change of acute type A aortic dissection

BACKGROUND: Acute type A aortic dissection (ATAAD) is a life-threatening disease. The aim of this study was to examine the role of tear size in the hemodynamic change and help improve the treatment level of this extremely dangerous disease. METHODS: A total of 120 ATAAD patients treated in our institution from November 2014 to December 2016 were divided into three groups according to proximal and distal tear size ratio (PDTSR). There were 35 patients in group A (PDTSR ≥2:1), 44 patients in group B (1:2< PDTSR <2:1), and 41 patients in Group C (PDTSR ≤1:2). Three computational fluid dynamics (CFD) models with different PDTSRs were established to investigate the hemodynamic difference in the three groups. RESULTS: The mean age (± SD) of the 120 patients included in this study was 47.7±10.1 years. Patients in Group A had a significantly larger proximal tear size (219.1±76.5 vs. 127.7±70.1 vs. 75.7±49.7 mm(2); P<0.001). The mortality of the patients in group A was significantly higher than those in group B and group C in the acute phase (37.1% vs. 2.3% vs. 2.4%, respectively; P<0.001). A proximal tear larger than a distal tear was found to be significantly associated with preoperative death in logistic regression analysis (odds ratio: 15.89; 95% confidence interval, 2.702–93.477; P=0.002). CONCLUSIONS: A proximal tear larger than a distal tear was associated with a significantly high-pressure difference between false and true lumens and more blood flow into the false lumen. In such cases, patients would experience extremely high mortality and morbidity.