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Effects of selective and nonselective beta-blockade on 24-h ambulatory blood pressure under hypobaric hypoxia at altitude

Bilo, Grzegorza; Caldara, Gianlucaa; Styczkiewicz, Katarzynac; Revera, Miriama; Lombardi, Carolinaa; Giglio, Alessiaa; Zambon, Antonellad; Corrao, Giovannid; Faini, Andreaa; Valentini, Mariaconsueloa; Mancia, Giuseppeb; Parati, Gianfrancoa,b

doi: 10.1097/HJH.0b013e3283409014
Original papers: Therapeutic aspects

Background: Little is known about the effects of cardiovascular drugs at high altitude.

Objective: To assess 24-h blood pressure (BP) and heart rate (HR) during short-term altitude exposure in healthy normotensive persons treated with carvedilol or nebivolol.

Methods: Participants were randomized in double-blind to placebo, nebivolol 5 mg once daily or carvedilol 25 mg b.i.d. Tests were performed at sea level (baseline and after 2 weeks treatment) and on second to third day at altitude (Monte Rosa, 4559 m), still on treatment. Data collection included conventional BP, 24-h ambulatory BP monitoring (ABPM), oxygen saturation (SpO2), Lake Louise Score and adverse symptoms score.

Results: Twenty-four participants had complete data (36.4 ± 12.8 years, 14 men). Both beta-blockers reduced 24-h BP at sea level. At altitude 24-h BP increased in all groups, mainly due to increased night-time BP. Twenty-four-hour SBP at altitude was lower with carvedilol (116.4 ± 2.1 mmHg) than with placebo (125.8 ± 2.2 mmHg; P < 0.05) and intermediate with nebivolol (120.7 ± 2.1 mmHg; NS vs. others). Rate of nondipping increased at altitude and was lower with nebivolol than with placebo (33 vs. 71%; P = 0.065). Side effects score was higher with carvedilol than with placebo (P = 0.04), and intermediate with nebivolol. SpO2 at altitude was higher with placebo (86.1 ± 1.2%) than with nebivolol (81.7 ± 1.1%; P = 0.07) or carvedilol (81.1 ± 1.1%; P = 0.04).

Conclusions: Both carvedilol and nebivolol partly counteract the increase in BP at altitude in healthy normotensive individuals but are associated with a lower SpO2. Carvedilol seems more potent in this regard, whereas nebivolol more effectively prevents the shift to a nondipping BP profile and is better tolerated.

aDepartment of Cardiology, S. Luca Hospital, IRCCS, Istituto Auxologico Italiano, Italy

bDepartment of Clinical Medicine and Prevention, University of Milano-Bicocca, Milan, Italy

cI Department of Cardiology and Hypertension, Jagiellonian University Medical College, Krakow, Poland

dDepartment of Statistics, University of Milano-Bicocca, Milan, Italy

Received 4 June, 2010

Revised 29 August, 2010

Accepted 14 September, 2010

Correspondence to Gianfranco Parati, MD, Istituto Scientifico Ospedale San Luca, Istituto Auxologico Italiano, Piazzale Brescia 20, 20149 Milan, Italy Tel: +39 02 619112980; fax: +39 02 619112956; e-mail: gianfranco.parati@unimib.it

© 2011 Lippincott Williams & Wilkins, Inc.