Cinzia Santucciu

Blood pressure variability, cardiovascular risk and antihypertensive treatment

Twenty-four hour blood pressure parameters: The use of ambulatory blood pressure monitoring techniques has shown clearly that 24-h average blood pressure is more closely related to the end-organ damage of hypertension than isolated office blood pressure readings. It has also provided evidence that the degree of blood pressure variability over a 24-h period may be independently related to the cardiovascular complications of hypertension. However, all the available data on this issue come from cross-sectional studies, and prospective evidence on the actual prognostic value of 24-h blood pressure parameters has only recently been provided for daytime blood pressure variability. There is still no prospective evidence concerning overall 24-h blood pressure variability. Antihypertensive agents and blood pressure variability: Available antihypertensive agents are unable to effectively buffer blood pressure variability. However, drugs with a long-lasting antihypertensive effect and an optimal trough: peak ratio may at least prevent further iatrogenic increases in the amplitude of blood pressure fluctuations. Beat-to-beat blood pressure monitoring: The ability of antihypertensive agents to actually reduce 24-h blood pressure variability needs to be demonstrated in future studies, using beat-to-beat blood pressure monitoring which is now possible by means of non-invasive techniques.

Hemodilution Reduces Clinic and Ambulatory Blood Pressure in Polycythemic Patients

Limited information is available for humans on whether blood viscosity affects total peripheral resistance and, hence, blood pressure. Our study was aimed at assessing the effects of acute changes in blood viscosity on both clinic and 24-hour ambulatory blood pressure (BP) values. In 22 normotensive and hypertensive patients with polycythemia, clinic and 24-hour ambulatory BPs were measured before and 7 to 10 days after isovolumic hemodilution; this was performed through the withdrawal of 400 to 700 mL of blood, with concomitant infusion of an equivalent volume of saline-albumin solution. Hematocrit, plasma renin activity, plasma endothelin-1, right atrial diameter (echocardiography), and blood viscosity were measured under both conditions. Plasma renin activity and right atrial diameter were used as indirect markers of blood volume changes. Plasma endothelin-1 was used to obtain information on a vasomotor substance possibly stimulated by our intervention, which could counteract vasomotor effects. Isovolumic hemodilution reduced hematocrit from 0.53+/-0.05 to 0.49+/-0.05 (P<.01). Plasma renin activity, plasma endothelin-1 and right atrial diameter were unchanged. Clinic blood pressure was reduced by hemodilution (systolic, 144.3+/-5.4 to 136.0+/-3.9 mm Hg[mean+/-SEM]; diastolic, 87.0+/-2.8 to 82.1+/-2.6 mm Hg, P<.05 for both) and a reduction was observed also for 24-hour average ABP (systolic, 133.6+/-2.9 to 129.5+/-2.7 mm Hg; diastolic, 80.0+/-2.0 to 77.3+/-1.7 mm Hg, P<.05 for both). The reduction was consistent in hypertensive patients (n = 12), whereas in normotensive patients (n = 10) it was small and not significant. Both clinic and 24-hour average heart rates were unaffected by the hemodilution. Thus, in polycythemia, reduction in blood viscosity without changing blood volume causes a significant fall in both clinic and 24-hour ambulatory BPs; this is particularly true when, as can often happen, blood pressure is elevated. This emphasizes the importance this variable may have in the determination of blood pressure and the potential therapeutic value of its correction when altered.

Variability in arterial diameter and compliance: compliance modulation reserve.

Background Some antihypertensive drugs are known to increase arterial compliance in hypertensives; how far compliance can be increased is unknown. Design We studied eight mildly hypertensive patients to determine how far radial artery compliance can be acutely increased, i.e. the extent of the compliance modulation reserve. Methods We evaluated radial artery compliance by a new technique, assessing it throughout the cardiac cycle before and after the intra-arterial infusion of a vasodilator agent (papaverine). Results Before papaverine, compliance decreased progressively through diastolic to systolic blood pressure values. This was the case also during the papaverine infusion. However, over the full systolo-diastolic pressure range, compliance was increased by about 40% with papaverine. Conclusions In hypertensive subjects radial artery compliance can be markedly increased on a acute basis, indicating that those antihypertensive drugs that improve compliance have a considerable reserve to act upon.

Clinical value of ambulatory blood pressure monitoring

&NA; This report reviews the evidence for and against clinical use of ambulatory blood pressure monitoring (ABPM) on a large scale. Such monitoring is supported by a number of data, among which is that the end‐organ damage associated with hypertension correlates more with 24‐h average blood pressure than with clinic blood pressure, the correlation becoming even closer with addition of blood pressure variability values. However, the evidence thus far collected is largely cross‐sectional. Furthermore, ABPM devices have limited accuracy and the procedure has a high cost. Therefore, while prospective studies on the prognostic value of ambulatory blood pressure are awaited, use of this approach should be restricted to a limited number of clinical circumstances (e.g., identification of white‐coat hypertension) and used only in specialized centers.

Radial artery compliance in essential hypertension: Effects of antihypertensive therapy with lacidipine

Objective: To evaluate the effects of antihypertensvie therapy with lacidipine on the increase in radial artery compliance observed in mild essential hypertensive patients methods: The stuudy was performed in eight mild to moderate essential hypertensive patients in whom clinic blood pressure, radial artery diameter and radial artery compliance were evaluated before and after 3 months administration of lacidipine, at a single daily dose of 4 mag. radial artery diameter and compliance were evaluabted by means of a high precision eacho-tracking deviceable to assess arterial compliance over the blood pressure oscillations that characterize the cardiac cycle Results: Lacidipine treatment caused a significant reduction in clinic systolic and diastolic blood pressure. while her heart rate was not modified by the drug. radial artery diameter and compliance were both reduced by lacidipine over the entire systolodiastolic blood pressure range. Conclusion: Chronic administration of lacidipine seems to reverse the increase in compliance treatment can reverse an increase in the smooth muscle component in the arterial wall induced by hypertension