Objective: Hospitals throughout Japan are being integrated and reorganized under the government's regional medical care plan. However, the effects on cardiovascular surgery practice remain unknown. In the year 2016, our institution employed hospital integration; we report its effects on patients with type A acute aortic dissection who underwent emergency surgery. Methods: This study included 89 patients who underwent emergency surgery for type A acute aortic dissection from May 2012 to December 2020. Evaluation items included preoperative patient factors, number of surgeries, surgical mortality, referral rate, patient transport time, transport distance, number of surgeries performed by young cardiovascular surgeons, and overtime work for surgery. Patients were categorized into pre-(group P: 29 patients) and post-integration (group A: 60 patients) groups, which were retrospectively compared. Results: Preoperative factors were not significantly different between the two groups. Operations accounted for 29 and 60 in groups P and A, respectively; they increased significantly after integration (p=0.005). Surgical mortality was 27.6 and 15% in groups P and A, respectively, with no significant difference (p=0.2). The referral rate was 17 (58.6%) and 21 (35%) patients in groups P and A, respectively; group A displayed a significantly lower referral rate (p=0.04). The interval from the onset of symptoms to arrival at the surgery cite was significantly reduced (p=0.01) in group A (112±140 min) compared to group P (206±201 min). There was no significant difference in the transfer distance between groups P (13.9±14.8 km) and A (13.5±16.2 km). The number of surgeries performed by young surgeons increased in 9 cases (31%) in group P and 34 cases (56.7%) in group A (p=0.02). Overtime work was substantially reduced:446±154 min in group P and 349±112 min in group A. Conclusion: Hospital integration resulted in increased number of acute aortic dissection surgeries and decreased interval time from the onset of symptoms to arrival at the surgery cite. The young surgeons performed more surgeries and reduced their overtime work.