[The noninvasive evaluation of the cardiovascular changes in physiological aging]

The physiological aging is frequently associated with structural alterations determining a loss of elasticity both of left ventricular wall (that goes towards hypertrophy), and of great and small arteries and arterioles (that have their compliance reduced). In fact, in our experience, the elderly have, in comparison with younger people, greater values of end diastolic thickness of the septum and of the posterior wall (respectively 10.7 +/- 1.5 vs 9.4 +/- 1 and 10.4 +/- 1.7 vs 9.0 +/- 0.9), of the aortic index, that is inversely related to arterial compliance (0.74 +/- 0.06 vs 0.66 +/- 0.05) as well as of minimal vascular resistances, expression of an impaired maximal vasodilation capacity of the arteriolar bed (4.27 +/- 1.08 vs 3.68 +/- 0.91). At cardiac level the global effect of these changes is a remodelling able to maintain a normal function both at rest and after exercise, i.e., a greater intervention of Frank-Starling mechanisms with increase of the end diastolic volume, in order to counteract the lower chronotropic response to catecholamines. At peripheral level the structural changes in the arterial tree (consequent to an increased collagen content in the intimal and medial components of the vessel walls) lead to an increase in blood pressure with aging: in our study by non-invasive blood pressure monitoring mean 24-hours blood pressure values have been the following ones: 116.4 +/- 3.8/72.1 +/- 7.2 mmHg in 25-35 years aged; 121.8 +/- 9.1/75.9 +/- 5.3 mmHg in 45-55 years aged; and 128.4 +/- 10.1/76.4 +/- 7.8 mmHg in aged more than 60 years. On the other hand, the greater cardiac output during stress, together with the lower arterial vasodilation (consequent also to the impaired function of the baroceptor reflexes) determines an exaggerated systolic blood pressure increase after exercise.