Marantic endocarditis and cancer: diagnosis, treatment and outcomes: a multicentric cohort study

Background Marantic endocarditis (ME) associated with cancer is a rare disease with a poor prognosis. Unlike infective endocarditis (IE), whose diagnosis and therapeutic management are based on strong evidence, ME management solely relies on clinical cases, autopsies and literature reviews of descriptive articles. Purpose To describe clinical characteristics, management therapies and outcome of patients presenting with ME associated with cancer. To assess the role of multimodal imaging in the diagnosis of this disease. Methods In a retrospective multicentric study including four tertiary centers for treatment of endocarditis in France and Belgium, patients with a diagnosis of ME were included. Demographic, imaging (echocardiography, PET-CT, computed tomography) and management data were collected. Long-term mortality was analyzed. Results Between November 2011 and August 2021, 47 patients with a diagnosis of ME were included. Mean age was 65±11 years. ME occurred in 43 cases (91%) on native valves. 89% (42 patients) were left-sided ME and the most common cardiac valve involved were aortic (34 cases, 73%) and mitral (26 cases, 55%). Systemic embolism was frequent (40 patients, 85% of cases). One year mortality was 55% (26 patients). 22 patients (46%) had a known cancer before ME and 25 cases (54%) were diagnosed thanks to paraclinical investigations. Most cancers were lung (19 cases, 40%) following by pancreatic cancers (10 cases, 20%). PET CT was performed in 30 patients (64%) and allowed a new diagnosis of cancer in 14 patients (30%). 41 patients (88%) were treated medically with anticoagulation therapy. 6 patients (12%) underwent valve surgery. Conclusion To our knowledge, our study included the largest cohort of patients presenting with ME. The prognosis of ME is poor due to its association with advanced malignancy and related to the frequency of thromboembolic events. Diagnosis of ME is challenging and multimodal imaging, especially PET CT seems to be very useful to distinguish IE and ME by revealing cancers. Funding Acknowledgement Type of funding sources: None.