Trousseau’s syndrome often occurs in patients with carcinoma of the pancreas, ovary, and lung. As mucin-producing adenocarcinoma from the gut or lung is commonly associated with NBTE [3, 4], NBTE can be one of the important primary episodes leading to a diagnosis of Trousseau’s syndrome.
The pathogenesis of NBTE is not fully understood, but the lesions classically occur in areas of high flow on valve leaflets. Blood flow may therefore contribute to the location of vegetation . It has been advocated that the pathogenesis may involve tissue factors and tumor-associated cysteine protease activity, tumor hypoxia, carcinoma mucin activity associated with platelet aggregation, and oncogene activation related to hypercoagulability . Of these, production of mucin by carcinoma is thought to play an important role in the onset of Trousseau’s syndrome [5, 6].
Histological examination of the resected valve remains the gold standard for diagnosis of NBTE. Culture-negative endocarditis can only be excluded histologically when there is a lack of acute valvular inflammation and absence of fungi or bacteria .
According to the latest European guidelines for NBTE, surgical intervention, valve debridement, and/or reconstruction are often not recommended unless the patient presents with recurrent thromboembolism despite well-controlled anticoagulation. Other indications for valve surgery are the same as for infective endocarditis. In the context of cancer, a multidisciplinary approach is recommended . Valve surgery was indicated for the present patient because the size of the vegetation had not changed despite anticoagulation.
There have been few reported cases of NBTE with Trousseau’s syndrome in which cardiac surgery has been possible . One major reason may be that most tumors are at an advanced stage at the time of detection. Indeed, Cestari et al. investigated patients with Trousseau’s syndrome in whom stroke had been the primary event and reported that the median survival was 4.5 months from the diagnosis of stroke; 25% of the patients died within 30 days .
According to the above guidelines, if there is no contraindication, NBTE patients should be anticoagulated with unfractionated or low-molecular-weight heparin or warfarin, although there is little evidence to support this strategy . Some investigators do not recommend warfarin usage because of the presence of non-vitamin K-dependent agents that may induce thrombotic coagulopathy . Few studies have investigated the effectiveness of direct oral anticoagulants in patients with Trousseau’s syndrome. Dabigatran has been reported to be ineffective for prevention of recurrent ischemic stroke . In the present patient, stroke recurred under apixaban administration preoperatively. Accordingly, we chose heparin, and no recurrent thromboembolic events were subsequently observed in the patient.