a These authors contributed equally to this work.Abstract: Acute pulmonary hypertension leading to right ventricular failure and circulatory collapse is usually caused by thromboembolic obstruction of the pulmonary circulation. However, in rare instances, other causes can be associated with a similar clinical presentation. We present and discuss the clinical histories of two patients with acute right ventricular failure due to an atypical cause of pulmonary hypertension, disseminated pulmonary tumor embolism.Keywords: acute pulmonary hypertension, acute right ventricular failure, neoplastic pulmonary hypertension. The acute onset of pulmonary hypertension (PH) associated with right ventricular (RV) failure is generally caused by deep venous thrombosis followed by proximal embolization of the pulmonary circulation. Much less commonly, other pathological processes can result in pulmonary vascular occlusion and acute PH, as illustrated by the report of two patients with massive obstruction of the distal pulmonary vasculature by circulating tumor cells followed by acute RV failure and death.
CASE REPORTSPatient 1 was a 67-year-old man with a history of nonmetastatic bladder cancer treated by cystectomy 9 months before presentation and a recent uncomplicated incisional hernia repair. He presented to a community hospital with dyspnea and general weakness. Physical examination, chest radiograph, and electrocardiogram findings and laboratory test results were unremarkable except for a urine culture positive for Escherichia coli. Treatment with oral ciprofloxacin was started. After 3 days, the patient's condition deteriorated, with worsening dyspnea and hypotension. Computed tomography (CT) of the chest was described as unremarkable and, in particular, ruled out pulmonary embolism or pneumonia. The patient was admitted to the intensive care unit (ICU) for possible urosepsis and was treated with piperacillin-tazobactam and norepinephrine. Because of further deterioration of his condition, he was transferred to our institution. On arrival, severe hypoxemia, lactic acidosis (lactate level, 15 mmol/L), and muscular exhaustion were noted, and urgent endotracheal intubation was required. The procedure was complicated by severe hypotension and pulseless electrical activity cardiac arrest. A transesophageal electrocardiogram (ECG) obtained during cardiopulmonary resuscitation (CPR) revealed massive RV dilatation. CPR was stopped after 45 minutes due to refractory cardiac arrest. Clinical diagnosis was cardiogenic shock due to acute RV failure of unknown etiology. Postmortem examination revealed innumerable carcinomatous microemboli massively showering pulmonary capillaries, which explained the resulting PH. As a consequence, myointimal hyperplasia and thrombosis of medium-sized arteries were observed, as was capillary congestion (Fig. 1A-1D). Tumor microemboli were also found in massively dilated hepatic sinusoids, the heart, the spleen, and the pancreas. Despite extensive sampling, tumor cells were found only within vessels, wi...