Pulmonary hypertension after ventriculoatrial shunt implantation

Ventriculoatrial (VA) shunts inserted for the treatment of hydrocephalus are known to be a risk factor for pulmonary hypertension. The aim of this study was to evaluate the incidence of pulmonary hypertension among adult patients with VA shunts.

All patients who had received a VA shunt at one of two institutions between 1985 and 2000 were invited for a cardiopulmonary evaluation. The investigation included a thorough history taking, clinical examination, echocardiography, and pulmonary function testing including diffusing capacity of the lung for carbon monoxide (DLCO). Pulmonary hypertension was defined as systolic pulmonary artery pressure>35 mm Hg at rest.

The study group consisted of 86 patients, of whom 38 (44%) could be examined. The patients' mean age was 47.1±18.4 years; the median interval between shunt insertion and cardiopulmonary evaluation was 15 years (range 5-20 years). Of the 38 patients, 20 (53%) had Doppler velocity profiles of tricuspid regurgitation that were adequate for the estimation of pulmonary artery systolic pressure. Doppler-defined pulmonary hypertension was observed in 3 patients (8%), 2 of whom underwent right heart catheterization. Chronic thromboembolic pulmonary hypertension was confirmed in both patients, and medical therapy, including anticoagulation, was started. The VA shunt was removed in both cases and replaced with a different type of device. Pulmonary function tests revealed a restrictive pattern in 15% and typical obstructive findings in 9% of patients. In 30% of patients the DLCO was less than 80% of predicted, and blood gas analysis showed hypoxemia in 6% of patients. No significant differences in pulmonary function tests were noted between the patients with and without echocardiographic evidence of pulmonary hypertension. However, patients with pulmonary hypertension had significantly lower DLCO values.

The authors detected pulmonary hypertension by using Doppler echocardiography in a significant proportion of patients with VA shunts. It is therefore recommended that practitioners perform regular echocardiography and pulmonary function tests, including single-breath DLCO in these patients to screen for pulmonary hypertension to prevent hazardous late cardiopulmonary complications.