Pulmonary hypertension during exercise in toxic oil syndrome

Toxic oil syndrome is a risk factor for pulmonary arterial hypertension (PAH) and new cases of this entity are emerging after more than 20 years since the initial toxic oil epidemic. Abnormal elevation of pulmonary systolic pressure with exercise may be considered an early marker of PAH in populations at risk. We aimed to analyze the pulmonary systolic pressure with exercise echocardiography in toxic oil syndrome patients. 50 toxic oil syndrome patients (cases), and 20 healthy control subjects were submitted to rest and peak exercise echocardiography (semi supine cycloergometer) measuring pulmonary systolic pressure. In toxic oil syndrome patients, pulmonary carbon monoxide diffusion capacity was also analyzed. Peak exercise pulmonary systolic pressure was statistically similar in cases and controls. Nevertheless, 8% of cases reached a pulmonary systolic pressure > or = 80 mmHg and this fact was associated with mild pulmonary arterial hypertension, reduced right ventricular function and abnormal pulmonary diffusion capacity in the rest study. A rest pulmonary systolic pressure cut-off value > or = 27 mmHg had a 100% sensitivity and 71% specificity to predict a peak exercise systolic pulmonary pressure > or = 80 mmHg. A minority of toxic oil syndrome patients develop severe pulmonary arterial hypertension during exercise. This abnormal response is associated with other markers of pulmonary vasculopathy. Further studies are needed to elucidate the relation between these findings and the likelihood to develop pulmonary arterial hypertension in the future.