Circadian blood pressure changes and myocardial ischemia in hypertensive patients with coronary artery disease

Abstract

Objectives: We sought to evaluate whether different circadian blood pressure (BP) changes could influence the occurrence of ischemic episodes in untreated and treated hypertensive patients with stable coronary artery disease (CAD).

Background: In hypertensive patients with CAD the occurrence of myocardial ischemia could be influenced by either high or low BP values. Ambulatory monitoring has shown that circadian BP profile is not uniform in hypertensive patients.

Methods: Twenty-one patients with a nighttime BP fall < 10% ("nondippers"), 35 with a nighttime BP fall between > 10% and < 20% ("dippers") and 14 with a nighttime BP fall > 20% ("overdippers") with CAD underwent simultaneous ambulatory BP and electrocardiographic monitoring before and during drug therapy with nitrates and atenolol or verapamil in a prospective, randomized, open, blinded end point design.

Results: Daytime BP was not significantly different among the groups both before and during therapy. Nighttime BP was different by definition. Treatment significantly reduced BP values in each group (p < 0.05). Daytime ischemic episodes did not differ among the groups either before or during therapy. Drug therapy significantly reduced daytime ischemia (p < 0.05). In untreated patients, nighttime ischemia was more frequent in nondippers than in dippers and overdippers (p < 0.05). Drug therapy significantly reduced nocturnal ischemia in nondippers (p < 0.05), had no significant effect in dippers and significantly increased nighttime ischemia in overdippers (p < 0.05). During treatment, nighttime ischemia was more frequent in overdippers than in dippers and nondippers (p < 0.05). The same results were achieved when ischemic episodes were defined with more restrictive criteria (ST segment depression > or = 2 mm).

Conclusions: Circadian BP changes can influence the occurrence of myocardial ischemia in untreated and treated hypertensive patients with CAD. Nocturnal ischemia was found to be more frequent in nondippers among untreated patients and in overdippers among treated patients, potentially suggesting different therapeutic approaches based on circadian BP profile.