Pulmonary hypertension in patients with chronic renal failure.

BACKGROUND

Many etiologies causing pulmonary hypertension (PH) have been reported, and one of the background disease seen with patients with PH is chronic renal failure (CRF); however, the pathogenesis of PH in this group of patients is not explained satisfactorily.

OBJECTIVES

The aims of this study were to evaluate the incidence of unexplained PH among patients with CRF and to suggest possible etiologic factors.

METHODS

Two hundred and eleven patients with CRF were evaluated and the ones who have comorbid conditions that cause PH were excluded. Pulmonary arterial pressure (PAP) and cardiac functions were evaluated by Doppler echocardiography. Arteriovenous fistula (AVF) flow was measured by Doppler sonography. The patients were followed for at least 6 months.

RESULTS

Forty-eight CRF patients (20 males, 28 females) were included: 23 were predialysis patients, and 25 patients received hemodialysis via AVF. Patients were followed for 7.5 +/- 1.01 months. Systolic PAP >35 mm Hg was found in 56% (14/25) of patients receiving hemodialysis (36.8 +/- 10.7 mm Hg) and in 39.1% (9/23) of predialysis patients (29.5 +/- 9.5 mm Hg). The parathyroid hormone level, cardiac output values and CRF duration were found to be increased in patients with elevated systolic PAP (p < 0.05). AVF flow and AVF duration were positively correlated with systolic PAP in patients receiving hemodialysis (p < 0.05). There was a negative correlation between systolic PAP and residual urine volume (p < 0.05). AVF compression in hemodialysis patients decreased systolic PAP from 36.8 +/- 10.7 to 32.8 +/- 10.5 mm Hg. Systolic PAP values were increased at the end of the study in the predialysis group, whereas they were decreased at the end of the follow-up in the hemodialysis group (36.9 +/- 10.5 and 32.04 +/- 10.5 mm Hg, respectively).

CONCLUSIONS

This study demonstrates a high incidence of PH among patients with CRF. CRF duration, AVF flow, parathyroid hormone level and cardiac output may be involved in the pathogenesis of PH. The effective hemodialysis and dry weight reduction decreased systolic PAP values.