Pulmonary hypertension: a rare but serious complication of ventriculoatrial shunts

Abstract

A 34-year-old woman presented with a 6-month history of progressive dyspnoea. Past history included cerebral palsy and epilepsy. At the age of 14 years she had a ventriculoatrial (VA) shunt for hydrocephalus secondary to congenital aqueduct stenosis. There was no past history of deep vein thrombosis, liver disease, appetite suppressant use, intravenous drug abuse or other systemic disease. On examination she was unwell with central cyanosis, tachypnoea (respiratory rate 36 breaths per minute), sinus tachycardia (heart rate 120 beats per minute), and blood pressure 100/60 mmHg. There was ankle oedema, raised jugular venous pressure, accentuated pulmonary second sound and a right ventricular gallop. Chest X-ray showed cardiomegaly with prominent pulmonary arteries (Figure 1). Electrocardiogram demonstrated right axis deviation, dominant R wave in V1 and ST depression across the precordial leads (Figure 2). On room air her arterial partial pressures of oxygen and carbon dioxide were 7.1 KPa and 3.2 KPa respectively. Transthoracic echocardiography showed dilated right ventricle and right atrium with severe tricuspid regurgitation and moderate pulmonary regurgitation. Estimated pulmonary artery pressure was 100 mmHg. There was no evidence of intracardiac thrombus and left ventricular systolic function normal. A ventilation perfusion scan showed multiple sub-segmental perfusion defects. Cardiac catheterization confirmed severe pulmonary hypertension (pulmonary vascular resistance 1048 dynes/sec/cm2) with normal left heart pressures and no intracardiac shunt. Calculated cardiac index was low (1.5 litre/min/kg) with high right atrial pressure (20 mmHg) and low mixed venous oxygen saturation (50%). Pulmonary angiography and chest computed tomogram with contrast showed thrombus in the main pulmonary trunk extending into the proximal right and left pulmonary arteries. Duplex ultrasonography of both legs suggested no evidence of deep vein thrombosis. A thrombophilia, vasculitis and infection screen was negative. The patient was commenced on nasal continuous positive airways pressure, high flow oxygen, intravenous heparin and intravenous colloid with haemodynamic stability maintained for the first 4 days. After this she became more hypoxic and hypotensive so fluids were stopped and a frusemide, dopamine and prostacyclin infusion commenced to reduce right ventricular distension with some improvement. Because of her deteriorating haemodynamic state, pulmonary thromboendarterectomy was performed with removal of extensive thrombus from the proximal pulmonary tree. The patient died in the immediate postoperative period. Postmortem showed a distended and hypertrophied right heart with extensive chronic thromboembolic changes in the distal pulmonary tree. The tip of the VA catheter in the right atrium had no signs of infection and at this time was free of thrombus. The coroner concluded cause of death was pulmonary hypertension secondary to longstanding thromboembolic disease.