Intraoperative quantitative angiography predicts midterm left subclavian artery patency after thoracic endovascular aortic repair.

BACKGROUND

Thoracic endovascular aortic repair (TEVAR) frequently requires coverage of the left subclavian artery (LSA) to achieve an adequate proximal landing zone, which carries the risk of LSA occlusion and associated ischaemic complications. No validated real-time intraoperative tool currently exists to assess LSA hemodynamics during TEVAR. This study aimed to identify hemodynamic predictors associated with midterm LSA patency after TEVAR involving LSA management.

METHODS

Patients who underwent TEVAR for aortic pathologies between April 2018 and December 2020 were retrospectively enrolled. Quantitative assessment of LSA blood flow before and after TEVAR was conducted using the angiography post-processing software, iFlow. Two key hemodynamic parameters, the differential of delayed time to peak (diff.dTTP) and peak ratio (diff.Pr) in the proximal (P), middle (M), and distal (D) areas of the LSA were extracted. LSA patency was determined through follow-up computed tomography angiography (CTA). Cox regression analysis was used to identify hemodynamic predictors for LSA patency.

RESULTS

A total of 94 patients [median age, 61 years; interquartile range (IQR), 51.00-65.75 years; 83.0% male] were included, with 7 patients (7.4%) experiencing LSA occlusion during follow-up (median duration, 1,242 days; IQR, 968-1,356 days). The diff.dTTPs were identified as independent risk factors for midterm LSA occlusion [diff.dTTP.P: hazard ratio (HR) =30.0, P<0.001; diff.dTTP.M: HR =6.1, P<0.001; diff.dTTP.D: HR =5.1, P<0.001]. These hemodynamic parameters provided incremental prognostic value for midterm LSA occlusion [diff.dTTP.P: area under the curve (AUC) =0.957; diff.dTTP.M: AUC =0.921; diff.dTTP.D: AUC =0.938].

CONCLUSIONS

iFlow provides a real-time quantitative approach for evaluating LSA hemodynamics during TEVAR. The diff.dTTP values can predict midterm LSA patency and may guide LSA management strategies during TEVAR.