Intermediate endpoints for atherosclerosis in hypertension.
BACKGROUND
Event-based trials of antihypertensive therapy, although they have been essential in showing the beneficial effects of antihypertensive therapy on cardiovascular morbidity and mortality, could not answer the question whether antihypertensive therapy influences the development of atherosclerosis. Trials using measurements of plaque growth as endpoints are necessary.


METHODS
The traditional approach of using quantitative coronary arteriography for assessing the course of coronary artery disease during treatment cannot obviously be used in uncomplicated hypertensive patients. B-mode quantitative ultrasound assessment of intima-media thickness (IMT) of the carotid artery wall is now being used in several trials comparing different antihypertensive drugs. The major advantage of this approach is that it is non-invasive; it has also been demonstrated that IMT measurements are well reproducible. Limits of normality, definition of plaques and rate of growth of IMT in hypertension are still uncertain, however. Additionally, ultrasonographic techniques do not clearly distinguish between media and intima, and it is difficult to decide how many of the carotid wall lesions observed in hypertension are due to media hypertrophy related to hypertension or to intima changes related to atherosclerosis, although it is likely that the largest lesions have an atherosclerotic component.
Baseline data from two recent trials, the VHAS and the ELSA, indicate that carotid wall lesions are highly prevalent in hypertension, but the prevalence level obviously depends on the criteria used for defining these lesions. It is known that elevated systolic blood pressure is an important risk factor for carotid lesions, and epidemiological surveys have shown that increased carotid IMT is more frequently associated with history and signs of coronary artery or cerebrovascular disease. Some evidence from a prospective study is also available, and the VHAS findings support this conclusion. Trials of antihypertensive therapy using IMT as endpoint are, therefore, likely to provide clinically useful information.
Zanchetti
A
A
Istituto di Clinica Medica, University of Milan, Ospedale Maggiore, Italy.
D000792:Angiography; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001161:Arteriosclerosis / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000188:drug therapy; D011379:Prognosis; D018617:Ultrasonography, Doppler, Pulsed
D000959:Antihypertensive Agents