Effect of Rivaroxaban on Fibrinolytic Therapy in Massive Pulmonary Embolism: Two Cases
A 61-year-old woman was admitted to our hospital with a 4-day history of repeated syncope. She had felt dyspnea on exertion even in daily life since the last 2 weeks. The loss of consciousness was accompanied by syncope but abnormal neurologic sign was not shown. She was never a smoker and had been on hormone replacement therapy for abnormal uterine bleeding since the last 3 months. On admission, blood pressure was 104/70 mm Hg, heart rate was 94 beat/min, respiratory rate was 20 breath/min, and body temperature was 36.8℃. All of a sudden, her blood pressure decreased to 80/40 mm Hg for over 15 minutes on the same day. The physical examination was grossly normal. Arterial blood gas analysis (aBGA) on room air was 7.442 in pH, 27.7 mm Hg in PaCO2, 51 mm Hg in PaO2, 18 mmol/L in HCO3-, and 87% in O2 saturation. Echocardiography showed right ventricular (RV) hypokinesia with a D-shaped left ventricle (LV) and pulmonary hypertension. Computed tomographic (CT) pulmonary angiogram with lower extremity CT venogram showed extensive bilateral acute PE with deep vein thrombosis (DVT) in the right lower extremity and enlarged right cardiac chambers (). The brain CT was normal. D-dimer, N terminal-pro-brain natriuretic peptide (NT-pro-BNP), and high sensitive troponin-T was 2,923 ng/mL (range, 0-243 ng/mL), 316 pg/mL (range, 0-97.3 ng/mL), and 0.029 ng/mL (range, 0-0.015 ng/mL), respectively.\nAccording to the known protocol for massive PE, a high dose of unfractionated heparin (UFH) with 10,000 U was intravenously injected once. The maintaining dose of UFH was continuously infused at the rate of at least 1,250 U/hr until the activated partial thromboplastin time (aPTT) reached 80 seconds. Then, recombinant tissue plasminogen activator (rt-PA) of 100 mg was administered via a peripheral vein for 2 hours while a high dose of UFH was withheld. The aPTT was checked every 4 hours until aPTT reached below 80 seconds. Rivaroxaban with 15 mg twice daily was administered instantly without resumption of the high dose UFH after aPTT reached below 80 seconds. Her hospital stay was 4 days. The dose of rivaroxaban was changed from 30 mg/day to 20 mg/day after 3 weeks. Two months passed and she denied dyspnea on exertion even during hard work and any bleeding complications.