The 24-hour blood pressure pattern: does it have implications for morbidity and mortality?

The onset of adverse cardiovascular events demonstrates a circadian pattern that reaches a peak in the morning shortly after awakening and arising. A parallel, 24-hour cyclical pattern has also been observed in the activities of various physiologic measurements, including blood pressure, heart rate, sympathetic nervous system activity, and platelet adhesiveness. Although a direct link has not yet been established, it can be postulated that the early morning surge in blood pressure may be a factor in precipitating acute cardiovascular episodes. Similar to the early morning blood pressure surge, blood pressure variability throughout the day appears to be a further independent risk factor for hypertensive target organ damage. Thus, it is reasonable to select an antihypertensive agent that offers smooth and well-sustained blood pressure control for the full 24-hour dosing interval, including the vulnerable early morning period. The results of clinical trials using ambulatory blood pressure monitoring have shown that telmisartan, an angiotensin II receptor antagonist, possesses such properties. Whether or not these attributes of telmisartan might translate into improvements in cardiovascular morbidity and mortality will be explored in the Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET). This study will compare the effects of telmisartan 80-mg monotherapy, ramipril 10-mg monotherapy, or a combination of telmisartan 80 mg plus ramipril 10 mg, on cardiovascular endpoints in patients at high risk of cardiovascular events, several of whom are likely to be hypertensive at baseline. Inclusion of the telmisartan plus ramipril treatment arm will allow investigation of the potential advantages presented by combining an angiotensin-converting enzyme inhibitor with an angiotensin II receptor antagonist.