Ambulatory blood pressure monitoring as an investigative tool for characterizing resistant hypertension and its rational treatment.

Ambulatory blood pressure (BP) monitoring has matured into a useful methodology that obtains automated measurements of brachial artery BP during a 24-hour period. Cardiovascular outcomes in the treated patient with hypertension are often better predicted by ambulatory BP than by office pressures. Consensus guidelines have advocated lower goals of treated office BP in the majority of patients with hypertension; guidelines for the goal of ambulatory BP are needed as well. Recently, prospective cohort studies have shown that individuals whose clinic pressure is relatively normal but whose 24-hour BP is elevated are more likely to have a cardiovascular event than individuals with both normal clinic BP and ambulatory BP. Along with the knowledge gained from analyses of higher-risk hypertension patients, recommendations can now be made for how to use ambulatory BP monitoring in clinical practice. For example, ambulatory BP monitoring may be useful in verifying 24-hour control in high-risk patients whose office BP appears to be normal at rest or during the peak effect time of their antihypertensive agents. Evidence is mounting from studies that support the use of ambulatory BP monitoring in patients with resistant hypertension at the time of diagnosis and following clinically guided therapy.