Objective: This study case is about pulmonary emboli with right ventricle thrombus in a patient treated with rivaroxaban for bilateral distal deep vein thrombosis and underlying pulmonary neoplasia. It highlights the possible individual resistance of NOACs therapy in a patient with DVT and neoplasia

Methods: We present a case of a 55-year-old male who is admitted in our clinic for fatigability, dry cough and weight loss about 7 pounds in the last month and dyspnea. He was diagnosed two months ago with bila-teral distal deep vein thrombosis for which he received treatment with rivaroxaban 15mg twice daily during 21 days, followed by 20 mg daily. He is known with arterial hypertension and dyslipidemia. He is a smoker (30 PY) with relevant familial history, mother had pulmonary emboli and his father had esophageal neoplasia. On ad-mission, he was hemodynamically stable, on the phy-sical exam presents dyspnea, normal pulmonary mur-mur, without lung crackles, the respiratory rate was 22 breaths/min, dry cough, SaO2=84%, normal cardiac rhythm, right S3 heart sound, tricuspid systolic mur-mur gr III/VI, arterial blood pressure 130/60mmHgm, heart rate 96bpm, no other significant findings on the clinical exam.

Results: From the paraclinical examination, we obtai-ned a CBC with leukocytosis with neutrophilia, thro-mocitosis, eosinophilia, D-dimer test was positive. Markers for neoplasia was negative. Thrombophi-lic tests were negative. The ECG at admission: sinus rhythm, with right bundle branch and T wave negative. Echocardiography revealed normal LV ejection frac-tion, dilated right cavities, dilated pulmonary artery with pulmonary regurgitation and a non-homogeneo-us hyperechogenic mobile of 25 mm in the RV. On the computed tomography examination we assessed bilate-ral proximal pulmonary embolism, adenopathies for-ming an adenopathy block and an excavated right pul-monary nodular formation in the inferior right lobe. Treatment was started with UFH for 10 days, long-ac-ting nitrate, calcium blockers and aspirin with favorable evolution. Bone marrow biopsy was done and revealed minor hyperplasia of the erythrocyte series excluding lymphoma. At discharge, the RV thrombus disappea-red under anticoagulation with UFH. Bronchoscopy revealed infiltration of the main right bronchia and stenosis of the medium lobar bronchi. The diagnosis is established by histopathological exam and confirmed mediastinal adenopathies metastasis from pulmonary adenocarcinoma. The follow-up CT scan showed no pulmonary thrombus, with the persistence of mediasti-nal lymphadenopathy. The echocardiography 2 months later after the diagnosis of the pulmonary emboli found the normal right and left cavities with normal ventricu-lar function, with no pulmonary hypertension and no thrombus in RV. The patient was referred to an oncolo-gic ward and immunotherapy was initiated due to the presence.

Conclusions: Benefits of novel direct-acting oral anticoagulants include: no need to monitor INR levels, potentially decreased drug interactions and adverse events, but safety and efficacy in patients with neoplasia and DVT, are still being studied. From literature, we re-member the SELECT D study comparing rivaroxaban with dalteparin with a lower recurrence rate of VTE in patients who received rivaroxaban but a higher blee-ding rate. This case report is intended to highlight a no-ted anomaly to be taken into consideration for future practice, raising the issue of resistance at direct factor X inhibitors and selecting the patients at risk for lack of response to treatment. In conclusion, choosing the best anticoagulant therapy strategy should be tailored to the patient’s comorbidities and preference.