Effect of acetazolamide on pulmonary hemodynamics in COPD-patients going to altitude: a randomized trial

Abstract

Background: Chronic obstructive pulmonary disease (COPD) may predispose to symptomatic pulmonary hypertension at high altitude. We investigated if preventive acetazolamide treatment would attenuate the altitude-induced increase in pulmonary artery pressure (PAP) in lowlanders with COPD ascending to 3,100m.

Methods: In this placebo-controlled, double-blind trial, non-hypercapnic COPD patients GOLD2-3 living <800m, were randomized to receive either acetazolamide (125-0-250mg/day) or placebo starting 24h before ascent and while staying at 3,100m for 48 hours. Echocardiography was performed at 760m before medication and after the first night at 3,100m. PAP (presented as trans-tricuspid pressure gradient), heart rate (HR), cardiac output (CO) and pulse-oximetry (SpO2) were compared between groups.

Results: 112 patients, 68% male, (mean±SD) age 57±8y, FEV1 61±12%pred. were included. In 54 patients receiving placebo, PAP at 760 and 3,100m was 22±7 and 30±10mmHg, in 58 patients receiving acetazolamide corresponding values were 20±5 and 24±7mmHg; treatment effect (mean difference (95% CI)) was -5(-9 to -1)mmHg (allp<0.05). In the placebo group CO, HR and SpO2 at 760 and 3,100m were 4.5±1.1 and 4.9±1.0L/min and 69±11 and 76±11bpm, 95±2 and 88±3% (all p<0.05). The corresponding values in the acetazolamide were 4.7±1.2 and 4.4±0.9L/min, 71±11 and 74±10bpm, 94±2 and 90±3% (p<0.05 for HR and SpO2). Treatment effects: CO -0.6(-1.0 to -0.2)L/min, HR -5(-8 to -1)bpm and SpO2 2(1 to 3)%.

Conclusion: In lowlanders with COPD travelling to 3,100m preventive acetazolamide treatment attenuated the altitude-induced rise in PAP along with an improved oxygenation but decreased CO and HR.