Non-Dipping Phenomenon and Coronary Artery Disease in Men: An Association or an Independent Risk Factor?
Tarek M Mousa, M.D., Adel Allam, M.D., Ph.D., Steven Reichert, M.D., F.A.C.P., Terence Brady, M.D., F.A.C.P.,
Background: The aim of this work was to study the association between blunted night-time dipping of blood pressure (ie.non-dipping phenomenon) and coronary artery stenosis in men.
Subjects and Methods: Sixty-eight men (aged 52±11 years) with coronary artery disease (CAD) defined as ³70% diameter stenosis on coronary angiography in a major coronary blood vessel, and a control group of 68 men, matched for age and risk factors without angiographic evidence of CAD were studied by ambulatory blood pressure monitoring. Patients were defined as non-dippers when the night-time systolic and diastolic blood pressure (BP) decrease was <10%. Medications included b-blockers in 20 (15%), calcium antagonists in 39 (29%), angiotensin-converting enzyme inhibitors in 44 (32%), angiotensin II receptor blockers in 21 (15%), and diuretics in 37 (27%) of patients. A logistic regression model was used to define independent predictors of angiographic CAD. Covariates were symptoms, total cholesterol, day-time BP, and non-dipping.
Results: A larger proportion of patients with CAD were non-dippers as compared to control subjects (49 [72%] vs 31 [46%], p<0.005). In a logistic regression model, non-dipping was associated with coronary artery stenosis independent of other clinical parameters (odds ratio 3.6, 95% confidence interval 1.6-8.8).
Conclusions: Non-dipping phenomenon is independently associated with angiographic coronary artery stenosis in men. Based on these findings it could not be concluded that CAD and non-dipping phenomenon were causally related.