Blood pressure control in anticoagulated hypertensive patients.

OBJECTIVE

To compare the methods of office blood pressure (BP) measurement and ambulatory blood pressure monitoring (ABPM) to ensure optimal BP control in hypertensive anticoagulated patients.

PATIENTS AND METHODS

Seventy-eight patients who were receiving antihypertensive drugs and warfarin in a dose-adjusted approach to achieve therapeutic international normalized ratio because of the association of atrial fibrillation were enrolled in the study. Twenty-four hour ABPM was applied to all patients. For the assessment of optimal BP control, office BP measurements were compared with ABPM recordings. All patients were divided into 'good control' and 'poor control' groups with a cut-off level of 140 mmHg systolic blood pressure (SBP). The groups of patients with 'good control' and 'poor control' were further subdivided into four groups according to the cardiovascular outcome on the basis of ABPM reference threshold levels: 'true good control' or 'seemingly good control' and 'true poor control' or 'seemingly poor control' (white coat effect). Positive and negative predictive values of the office BP measurement method versus ABPM were estimated.

RESULTS

According to office measurements, 56.9% of all cases were in the 'good control' group and 43.1% were in the 'poor control' group. When we reclassified patients according to daytime and night-time mean SBP, we realized that they were in 'true good control', 'seemingly good control', 'true poor control', and 'seemingly poor control' groups with ratios of 25.5, 31.4, 21.6, and 21.6% on the basis of daytime systolic mean values and 19.6, 37.3, 35.3, and 7.8% on the basis of night-time systolic mean values, respectively. When we considered ABPM as a reference method, sensitivity, specificity, and positive and negative predictive values of office SBP measurements were 40.74, 54.17, 50.00, and 44.83% for daytime SBP mean values and 48.65, 71.43, 81.82, and 34.48% for night-time SBP mean values, respectively.

CONCLUSION

Poor control of SBP in patients with anticoagulant therapy may result in fatal events such as intracranial bleeding; thus, they are still under significant risk, although they are considered to have controlled BP with office measurements. ABPM is an essential method for accurate BP control in contrast to office BP measurement in anticoagulated patients.