Elevated arterial pressure levels increase the hemodynamic load on heart and vessels, thus leading to functional and structural abnormalities. Because cardiac and vascular changes increase the risk of cardiovascular disease, their reversal is an important target of antihypertensive therapy, even though the prognostic value of this regression has not been fully established. In patients with untreated mild-to-moderate essential hypertension and left ventricular hypertrophy, trandolapril, a new angiotensin-converting enzyme inhibitor, reduces blood pressure by decreasing total peripheral resistance and improves both systolic and diastolic ventricular function. The latter effect is not only functional in nature because, after long-term antihypertensive treatment, the improvement in diastolic ventricular function is detectable also after 1-month withdrawal of trandolapril. The concurrent reversal of left ventricular hypertrophy may contribute to the improved left ventricular diastolic function. However, plethysmographic studies suggest that long-term antihypertensive treatment with trandolapril is also able to reverse structural vascular changes in the forearm vascular bed, because after 1-month washout forearm peripheral resistance also is lower than in control conditions. Finally, in hypertensive patients, trandolapril induces significant increases in brachial artery compliance and diameter that persist after 1 month of withdrawal from treatment. The latter observation suggests that trandolapril also is able to reverse the structural changes of the large artery wall.(ABSTRACT TRUNCATED AT 250 WORDS)