TEVAR versus open aortic arch replacement in ex vivo perfused human thoracic aortas

Abstract

This study aims to assess the outcomes of therapeutic options for aortic arch pathologies by comparing thoracic endovascular aortic repair (TEVAR) with open arch replacement (OAR) using woven polyester grafts from a mechanical and biomechanical perspective, with emphasis on ex vivo perfused human thoracic aortas reproducing heart rate and stroke volume conditions. Eleven non-diseased thoracic aortas from human cadavers were divided into TEVAR ($n=5$) and OAR ($n=6$) and tested using a custom-built mock circulation loop. Pressure, diameter, and stroke volume were monitored during perfusion before and after the intervention. Samples undergoing TEVAR showed a higher ascending systolic pressure post-intervention than OAR (TEVAR: $137\pm 9$  mmHg vs OAR: $126\pm 6$  mmHg, $p=0.017$). After the intervention, a significant discrepancy in the mean pressure differences between the ascending and descending aorta $\Delta P$ was observed (TEVAR: $9\pm 3$  mmHg vs OAR: $1\pm 2$  mmHg, $p=0.004$). Input impedance at zero frequency, approximating Windkessel resistance, was higher for TEVAR than for OAR (TEVAR: $1.78\pm 0.04$ vs OAR: $1.66\pm 0.03$  mmHg s/ml, $p=0.004$). A correlation was found between the resistance and the negative peak of the time-normalized wave intensity analysis (Kendall’s coefficient $\tau =-0.35$ and $p=0.023$). Another correlation was observed between resistance and $\Delta P$ ($\tau =0.51$, $p=0.001$). Looking at the replication of heart rate and stroke volume over the course of the study, the observed differences can largely be attributed to the type of intervention. The results suggest that TEVAR has adverse effects compared to OAR, particularly with regard to left ventricular afterload. Clinicians should consider the possibility of increased afterload and altered wave dynamics when deciding on TEVAR, particularly in patients with pre-existing impaired cardiovascular conditions.