Relationship between endothelin-1 levels and pulmonary arterial hypertension in HIV-infected patients.

Objective: Pulmonary arterial hypertension (PAH) is a progressive, fatal disease with average survival of less than 3 years if left untreated. It is most common in patients infected with HIV. Although the pathogenesis in this population is not fully understood, it is thought that HIV infection, through the immune response and release of different inflammatory mediators such as endothelin-1, may contribute directly to endothelial damage. Our objective was to quantify endothelin-1 levels in HIV-infected patients and determine whether or not there is an association between this marker and PAH.
Design: A case-control study in patients attending an infectious diseases clinic.
Methods: The sample was composed of 79 patients divided into three groups: 23 HIV patients with PAH (HIV+/PAH+), 45 HIV patients without PAH (HIV+/PAH-) and a control group of 11 healthy individuals. The ratio between the HIV+/PAH- and HIV+/PAH+ groups was 2 : 1. Patients were matched by age, sex, risk group and viral load; the control group by age and sex. All patients had blood taken for endothelin-1 plasma quantification.
Results: We found lower endothelin-1 levels in the controls than in the HIV+/PAH- group [0.71 pg/ml (interquartile range, IQR 0.54-0.94) vs. 1.13 pg/ml (IQR 0.87-1.38); P = 0.005] and the HIV+/PAH+ cohort [1.16 pg/ml (IQR 0.86-2.37); P = 0.003]. Patients with severe PAH had higher endothelin-1 levels [2.94 pg/ml (IQR 1.81-6.33)] than patients with mild and moderate PAH.
Conclusion: Plasma endothelin-1 levels are higher in HIV patients with PAH than in the HIV-noninfected population and levels increase with the severity of the PAH.