Effect of previous cardiac surgery on the outcomes of acute type A aortic dissection repair: a nationwide cohort study

OBJECTIVES: The effect of previous cardiac surgery (PCS) on the outcomes of acute type A aortic dissection (ATAAD) repair remains controversial. This study compared the primary outcome (in-hospital mortality) and secondary outcomes (postoperative complications and post-discharge mortality/aortic reoperation rates up to 5 years) of patients who underwent ATAAD repair with and without PCS through a nationwide cohort analysis. METHODS: We used Taiwan's National Health Insurance Research Database to enroll patients who underwent ATAAD repair with and without PCS (94 and 4532, respectively) between 1 July 2004 and 31 March 2017. A 1:4 propensity score matching (PSM) was used to create well-balanced PCS (n = 74) and non-PCS (n = 296) groups. Results before and after PSM were aligned to determine the role of PCS in primary and secondary outcomes. RESULTS: Before PSM, the PCS group was older and had more comorbidities, including diabetes mellitus, heart failure, atrial fibrillation and malignancy, but less stroke history than the non-PCS group. More patients in the PCS group received coronary artery bypass grafting during the repair than in the non-PCS group. The PCS group had a higher in-hospital mortality than the non-PCS group. After PSM, the in-hospital mortality was similar between the 2 groups (27.0% vs 26.7%; P = 0.953). For patients who survived to discharge, the all-cause mortality up to 5 years for PCS and non-PCS groups were 29.7% and 18.4% (P = 0.015) before and 29.6% and 23.1% (P = 0.313) after PSM, respectively. The 2 groups had similar aortic reoperation rates up to 5 years before (13.5% vs 11.7%; P = 0.727) and after PSM (13.8% vs 11.6%; P = 0.776). CONCLUSIONS: Patients with PCS who underwent ATAAD repair showed higher in-hospital and long-term mortality rates than those without PCS when not controlled for confounding factors. However, the disparity disappeared after PSM, indicating that worse outcomes might be due to its old age and different perioperative characteristics.