Incidence Rates of Penn Classes and Class-Specific Mortality in Acute Type A Aortic Dissection Patients: An Epidemiologic Systematic Review and Meta-Analysis.

Acute type A aortic dissection (ATAAD) is a life-threatening emergency that is associated with a high morbidity and mortality rate. One of the complications is end-organ ischemia, a known predictor of mortality. The primary aims of this meta-analysis were to summarize the findings of observational studies investigating the utility of the Penn classification system and to analyze the incidence rates and mortality patterns within each class. The electronic databases PubMed, MEDLINE, and Embase were searched through to April 2023. These were filtered by multiple reviewers to give 10 studies that met the inclusion criteria. The extracted data included patient characteristics, and primary outcomes were the incidence rates of different Penn classes, along with the corresponding mortality for each class. Out of 1,512 studies identified during the initial search, 10 studies, including 4,494 patients, met the inclusion criteria. The pooled incidence of Penn A was highest at 0.55 (95% CI 0.52, 0.58), followed by Penn B at 0.21 (95% CI 0.17, 0.25), and finally Penn C at 0.14 (95% CI 0.11, 0.17). Patients with Penn BC were found to be at the highest risk of death, as their early mortality rates were 0.36 (95% CI 0.31, 0.41). Within those populations, the subtype with the highest individual mortality was Penn C at 0.21 (95% CI 0.15, 0.27), followed by Penn B at 0.19 (95% CI 0.15, 0.23) and Penn A at 0.07 (95% CI 0.05, 0.10). Among patients presenting with ATAAD, class A was most frequently observed, followed by classes B, C, and BC. These findings indicate an incremental increase in mortality rates with the progression of Penn classification.