The Penn Classification System for Malperfusion in Acute Type A Dissection: A 25-Year Experience

Area of Science:

• Cardiovascular Surgery
• Thoracic Surgery
• Aortic Dissection Research

Background:

• The University of Pennsylvania classification system (Penn class) is utilized to assess the impact of malperfusion on surgical outcomes in acute type A aortic dissection (aTAAD).
• Validation of the Penn class in a contemporary, larger patient cohort is crucial for its continued clinical utility.

Purpose of the Study:

• To determine the validity of the Penn class in a larger and more contemporary cohort of aTAAD patients.
• To compare the performance of the Penn class with other existing classification systems for aTAAD.

Main Methods:

• A retrospective analysis of 1192 patients who underwent aTAAD repair between 1993 and 2020.
• Patients were categorized into Penn classes based on preoperative malperfusion syndrome severity.
• Multivariable regression and bootstrapped C-statistic were employed to evaluate the association between Penn class and 30-day mortality.

Main Results:

• Mortality rates significantly increased with higher Penn classes, from 5% in class A to 35% in class B-C.
• Adjusted 30-day mortality showed significant increases for Penn classes B, C, and B-C compared to class A.
• The Penn class achieved a C-statistic of 0.77, outperforming alternative classification systems (P < .05).

Conclusions:

• The Penn class demonstrates excellent discriminatory ability for predicting 30-day mortality in patients undergoing repair of acute type A aortic dissection.
• This classification system offers a valuable tool for risk stratification and surgical decision-making in aTAAD management.