Incidence of Type B Aortic Dissection after Proximal Aortic Replacement in Patients with Connective Tissue Disease

R. Ahmad¹, A. Arora², K. Monaghan³, K. Gilbert², S. Bhirud³, K. M.. Kim⁴, S. Fukuhara⁵, H. Patel⁶, B. Yang^7
1Michigan State University, College of Human Medicine, Grand Rapids, Michigan ²University of Michigan, Michigan Medicine, Ann Arbor, Michigan ³Michigan Medicine, Ann Arbor, Michigan ⁴UT Health Austin, Austin, Texas ⁵University of Michigan, Michigan Medicine, Frankel Cardiovascular Cen, Ann Arbor, Michigan ⁶University of Michigan Medical Center, Ann Arbor, Michigan ⁷University of Michigan / Michigan Medicine, Ann Arbor, Michigan

Purpose:

Objective: To evaluate the long-term outcomes and incidence of type B aortic dissection (TBAD) after proximal aortic replacement in patients with or without connective tissue disease (CTD)

Methods: From 1996 to 2022, 2233 patients underwent proximal aortic replacement (aortic root, ascending or arch). Of these, 59 patients had CTD with tricuspid aortic valve morphology (CTD group) and 832 patients had no CTD with tricuspid aortic valve morphology (no-CTD group). Patients who underwent TEVAR, had active endocarditis, or any history of aortic dissection were excluded. Data was obtained from medical record review, the local STS database, and the national and Michigan death index. Primary outcomes were long term survival and incidence of TBAD after surgery.

Results: Compared to the no-CTD group, the CTD group was younger (55 vs. 67 years) and had fewer comorbidities including chronic lung disease (1.9% vs. 12%), diabetes (1.7% vs. 13%), and coronary artery disease (9.6% vs. 34%). Intraoperatively, compared to the no-CTD group, the CTD group had more root replacement (44% vs. 32%) longer CPB time (215 vs. 201 minutes, longer cross-clamp time (171 vs. 155 minutes), but fewer concomitant CABG (1.7% vs. 19%) and blood product use (26% vs. 70%). Postoperatively, the CTD group required less prolonged ventilation (3.8% vs. 18%) and had a shorter ICU stay (46 vs. 66 hours) compared to the no-CTD group. All other postoperative outcomes were similar, including operatively mortality (0% in CTD vs. 3.4% in no-CTD, p=0.25).

The 10-year survival was higher in the CTD group compared to the no-CTD group (79% in CTD vs 61% in no-CTD, p=0.007). A multivariable regression Cox model showed the hazard ratio of CTD for long-term mortality was 0.7, p=0.49. Using death as a competing factor, the cumulative incidence of TBAD was higher in the CTD group compared to the no-CTD group over 15 years (18% vs. 3.2%, p=0.02).

Conclusion: Compared to patients with no-CTD, proximal aortic replacement in CTD patients achieved similar long-term survival but had an increased risk of future type B dissection. The stiffer Dacron graft might promote downstream aortic pathology. These patients need more careful long-term surveillance of the descending aorta after any proximal aortic procedure.

Identify the source of the funding for this research project: NHLBI of NIH R01HL141891, and R01HL151776, Phil Jenkins and Darlene & Stephen J. Szatmari Funds.