Date of Award

January 2025

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Roland Assi

Abstract

Acute type A aortic dissection is a surgical emergency associated with significantmorbidity and mortality. Debate persists regarding the necessity of immediate surgical management versus prioritizing anti-impulse therapy or revascularization techniques, particularly in the presence of malperfusion or malperfusion syndromes. This study evaluates the role of emergent surgical intervention for acute type A aortic dissection in patients with malperfusion syndromes, categorized according to the University of Pennsylvania (Penn) classification system. A retrospective cohort analysis was conducted on 80 patients who underwent surgical repair for acute type A aortic dissection at Yale-New Haven Hospital between October 2019 and October 2022. Multivariate logistic regression analysis was utilized to identify predictors of mortality. Patients were divided into three groups: Penn class A (n=27, no malperfusion), Penn class B (n=22, localized malperfusion), and Penn class C (n=31, global malperfusion with circulatory shock). The mean patient age was 65.2 ± 13.7 years, and 65% of the cohort were male. Cerebral malperfusion emerged as the most common subtype (P<0.001). The predominant surgical approach involved hemiarch aortic replacement with aortic valve/root repair. Antegrade thoracic endovascular aortic repair was more frequently performed in Penn class B and C patients compared to those in class A (50.0%, 41.9%, vs. 14.8%, P=0.02). Postoperative complications were common, with pneumonia occurring in 23.8% of patients, renal failure in 48.8%, and unplanned reoperations in 18.8%—primarily due to bleeding. Strokes were observed in 10% of cases, predominantly among patients with preoperative neurologic deficits, and none occurred in Penn class A. Persistent neurologic deficits were significantly more frequent in Penn class C compared to Penn class B (19.4% vs. 9.1%, P=0.049). Both malperfusion groups showed a strong association with renal failure and dialysis requirements. Patients in Penn class C experienced higher rates of pneumonia (38.7%, P=0.04) and tracheostomy (35.5%, P=0.003). The overall postoperative mortality rate was 10%, with the highest mortality in Penn class C (19.4%, P=0.048). Despite these differences, three-year post-discharge survival did not vary significantly across groups (Log- rank, P=0.57). Immediate surgical intervention yielded favorable outcomes, with a 90% survival rate and neurological recovery in 80% of patients. Circulatory shock emerged as the most critical predictor of operative mortality, followed by visceral malperfusion. However, long-term survival after hospital discharge was independent of initial clinical presentation. Our study thus shows that immediate surgical repair for acute type A aortic dissection, regardless of Penn classification, achieves excellent short-term outcomes, with a high survival rate and neurological recovery in the majority of patients. While circulatory shock and visceral malperfusion are significant predictors of operative mortality, the long-term survival after hospital discharge is not influenced by the initial clinical presentation.

Comments

This thesis is restricted to Yale network users only. It will be made publicly available on 05/14/2027

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