Prevention of Retrograde Ascending Aortic Dissection by Cardiac Pacing During Hybrid Surgery for Zone 0 Aortic Arch Repair

Abstract

Retrograde type A dissection (RTAD) after zone 0 hybrid aortic arch repair is highly lethal and not infrequent complication. The aim of this study was to assess the safety and effectiveness of rapid cardiac pacing as an adjunctive tool to prevent RTAD during or after hybrid procedures for zone 0 disease. We performed a retrospective review of 42 consecutive patients with zone 0 hybrid aortic arch repair between November 2004 and January 2018. Right ventricular pacing was carried out through unipolar electrodes attached to the epicardium of the right ventricle through the sternotomy (the indifferent electrode was in the subcutaneous tissue). Pacing was utilised during the clamping of the ascending aorta, release of the aortic clamp, and stent-graft deployment. Operative indications were aortic arch aneurysm 45% (n=19), aortic arch dissection 45% (n=19), traumatic rupture of isthmus 7% (n=3), and type IA endoleak 2% (n=1). Urgent procedures 48% (n=20). The mean proximal aortic diameter was 34.14±2.9mm. Mean stent-graft oversizing was 12.97±3.4%. The 30-day mortality rate was 14% (n=6). RTAD was observed in 7% (n=3). The actuarial survival rate was 74% over a mean follow-up of 50±30.2months. Since January 2013, rapid right ventricular pacing (overdrive pacing at a rate of 200 beats/min) was systematically used (n=24). No RTAD was observed in this group of patients. Rapid right ventricular pacing reduced significatively the risk of RTAD (P=0.038). Rapid right ventricular pacing is an effective method of inducing hypotension and appears to decrease the risk of retrograde type A dissection after zone 0 hybrid aortic arch repair.