Epidemiologic and Clinical Characteristics of Marantic Endocarditis: A Systematic Review and Meta-analysis of 416 Reports

Nonbacterial thrombotic endocarditis (NBTE) is a distinctive condition marked by the presence of aseptic fibrin depositions on cardiac valves due to hypercoagulability and endocardial damage. There is a scarcity of large cohort studies clarifying factors associated with morbidity and mortality of this condition. A systematic literature review was performed utilizing the PubMed, Embase, Cochrane, and Web-of-Science databases to retrieve case reports and series documenting cases of NBTE from inception until September-2022. A descriptive analysis of basic characteristics was carried out, followed by multivariate regression analysis to identify risk factors associated with morbidity and mortality. A total of 416 case reports and series were identified, of which 450 patients were extracted. The female-to-male ratio was around 2:1 with an overall sample median age of 48 (interquartile range [IQR]:34–61). Stroke-like symptoms were the most common presentation and embolic phenomena occurred in 70% of cases, the majority of which were due to stroke. Cancer was associated with higher embolic complications (aOR:6.38, 95% CI = 3.75-10.83, p < 0.01) in comparison to other NBTE etiologies, while age, sex, and vegetation size were not (p > 0.05). All-cause in-hospital mortality was 36%, with cancer etiology being associated with higher mortality: 56% (aOR:3.64, 95% CI = 1.57-8.43, p < 0.01) in comparison to other NBTE etiologies:19%. A significant decrease in NBTE mortality was seen in recent years in comparison to admissions that occurred during the 20th century (aOR:0.07, 95% CI = 0.04-0.15, p < 0.01). While there has been an observed improvement in overall in-hospital mortality rates for patients admitted with NBTE in recent years, it is important to note that cases associated with a cancer etiology are still linked to high morbidity and mortality during hospitalization.