Angelo Cherchi

Estradiol-17β reduces blood pressure and restores the normal amplitude of the circadian blood pressure rhythm in postmenopausal hypertension

After menopause, both systolic (SBP) and diastolic (DBP) blood pressure (BP) become higher in women than in men of the same age, suggesting that estrogen deficiency may influence the age-related increase in BP. We studied 30 postmenopausal women (mean age, 55 +/- 5.7 years; time from menopause, 2-5 years) affected by mild hypertension with no target-organ complications by means of 24-h BP monitoring. None of the group were undergoing estrogen replacement therapy or taking antihypertensive drugs. According to a randomized, double-blind protocol, subjects received patches of transdermal estradiol-17beta (E2) or a matched placebo, with crossover after a 7-day washout period. In 12 patients the 24-h peak-to-trough variation in SBP and DBP amounted to less than 10% (nondippers). Administration of E2 significantly decreased 24-h SBP and DBP in the whole cohort (P < .05). Furthermore, E2 restored the expected reduction in BP during nighttime in the nondipper subgroup. It is well known that estrogen replacement therapy protects against the development of both cardiovascular diseases and stroke. Our data suggest that this activity could be attributed, at least in part, to the activity of E2 in preserving physiologic circadian fluctuation of BP.

Effects of Acute Administration of Transdermal Estrogen on Postmenopausal Women With Systemic Hypertension

We studied 16 postmenopausal women with mild to moderate hypertension according to a randomized, double-blind protocol. They received patches of transdermal estradiol-17beta rated to deliver 100 mg/day of substance or matched placebo. A 24-hour ambulatory blood pressure (BP) monitoring was performed at baseline and after drug administrations. Our data show that estradiol-17beta exerts beneficial effects, both in lowering elevated BP levels and in maintaining a uniform BP control over 24 hours. Estrogen replacement therapy could be considered when significant changes in BP occur during the postmenopausal period.

Effects of acute administration of natural progesterone on peripheral vascular responsiveness in healthy postmenopausal women

Peripheral vascular responses to acute administration of natural progesterone were studied in 12 postmenopausal women (mean +/- SD age 50.3 +/- 4.8 years) with no evidence of cardiovascular disease. According to a randomized, double-blind protocol, all subjects were given natural progesterone as a vaginal cream, able to produce a rapid peak and decay of plasma hormone concentrations, or matched placebo, with crossover after a 1-week washout period. Forearm blood flow and peak flow after ischemic stress (ml/100 ml/min), local vascular resistance (mm Hg/ml/100 ml/min), venous volume (ml/100 ml), and venous compliance (ml/100 ml/mm Hg) were measured by strain-gauge venous occlusion plethysmography at baseline and after progesterone or placebo administration. Plasma norepinephrine concentrations were determined by high-performance liquid chromatography with electrochemical detection. Progesterone sharply decreased forearm blood flow (p <0.01) through an increase in local vascular resistance (p <0.01). Measures of venous function remained unchanged. Although the hormone increased circulating norepinephrine concentrations (p <0.05), there were no significant changes in mean arterial pressure or heart rate. Furthermore, progesterone reduced the local vasodilator capacity, shown by a decrease in forearm delta flow (difference between peak flow and basal flow, p <0.05). Compared with the well-known effect of estrogen, progesterone exerted an opposite action on peripheral vascular responsiveness. Peripheral circulatory changes may be attributed to a direct activity of progesterone on the arterial wall and may in part reflect a modulation of the hormone on peripheral sympathetic tone. Consideration must be given to the hypothesis that the addition of progestin may attenuate the beneficial effects of unopposed estrogen replacement therapy in postmenopausal women.

Regurgitant Flow of Mitral Valve Prostheses: An Intraoperative Transesophageal Echocardiographic Study

To assess the regurgitant characteristics of mitral biologic and mechanical prostheses immediately after implantation, intraoperative transesophageal echocardiography was performed in 27 patients, aged 32 to 69 years, undergoing open-heart surgery for rheumatic heart disease (n = 19), mitral valve prolapse (n = 3), malfunctioning prostheses (n = 3), or periprosthetic leaks (n = 2). The prostheses included 13 biologic (Carpentier-Edwards) and 14 mechanical valves (five Starr-Edwards, five Medtronic-Hall, and four Bjork-Shiley). Physiologic transvalvular regurgitant flow was detected in both biologic and mechanical prostheses. The spatial extent of the regurgitant jets was usually greater in the mechanical than in the biologic valves, and systolic jets, characteristic of each type of valve, were visualized consistently. Trivial periprosthetic jets (PPJs) were observed in many implanted valves (14/27). The median maximal jet area was 0.46 cm2 (range 0.1 to 1.5 cm2). Cardiopulmonary bypass was reinstituted in two patients. In one patient a PPJ was judged extensive enough (area 3.6 cm2) to warrant surgical revision of the implant, but no dehiscence was found. In the other patient a turbulent PPJ (area 5.5 cm2) was associated with a 0.5 cm dehiscence at the surgical inspection. In conclusion, (1) all mitral prostheses exhibit physiologic transvalvular regurgitation, (2) trivial mitral PPJ is a common finding in newly implanted mitral valves and does not require the revision of the implant, and (3) further experience based on larger series of patients is required to determine the maximal acceptable size of a mitral PPJ detected by intraoperative transesophageal echocardiography.

Propionyl carnitine in stable effort angina.

SummaryThe aim of this study was to investigate the antiischemic activity of propionyl carnitine (PC) in 18 informed, volunteer male patients, aged 37–70, suffering from a typical stable effort angina. The study design was randomized, balanced, crossover, and double blinded. The study lasted 75 days. In the first 15 days of washout the patients performed two maximal symptom-limited bicycle tests to verify the repeatability of the parameters examined. Then one group received PC for 30 days 500 mg three times a day, and the other group received placebo (PL) three times a day. At the end of 30 days the groups exchanged treatments. At the end of each period, 2 hours after the last oral administration, the patients performed a maximal symptom-limited bicycle exercise test with increased loads of 10 watts/min. No significant differences were observed between the two tests performed during the wash-out period, for a 1mm ST-segment depression time, for the time to the end of exercise, and for the rate x pressure product at the same experimental time. The oral administration of PC in coronary patients increased both the 1 mm ST-segment depression time and the time to the end of exercise. Furthermore, the drug reduced the ischemic depression of ST at maximal common work and at maximal work. After PC, the rate x pressure product was not significantly different in relation to placebo at submaximal and maximal exercise. Thus PC seems to have an antiischemiclike effect, probably related to its metabolic activity.

Detection of microbubbles released by oxygenators during cardiopulmonary bypass by intraoperative transesophageal echocardiography

Abstract Despite the improvements in cardiopulmonary bypass techniques, release of microbubbles in the systemic arterial circulation still occurs. It is believed that microemboli, prolonged arterial hypotension, defective cerebral blood flow autoregulation and nonpulsatile flow during cardiopulmonary bypass play a role in determining neurologic damage after cardiopulmonary bypass.1,2 Gaseous and particulate microemboli may originate from the pump-oxygenator system as well as from the cardiac chambers and pulmonary veins.1,3 In this study, transesophageal echocardiography was used to detect microbubbles reaching the arterial circulation during cardiopulmonary bypass. Two different types of oxygenators (bubbles and hollow fibers) were used to assess differences in their production of microbubbles.

Bromocriptine reduces plasma noradrenaline and 3,4-dihydroxyphenylacetic acid in normal and hypotensive subjects.

SummaryThe effect of a single oral dose of bromocriptine 2.5 mg was evaluated in 11 normotensive and 6 hypertensive volunteers. 150 min after drug administration, a significant decrease in plasma noradrenaline concentration from 202 to 124 pg/ml in normotensive and from 197 to 119 pg/ml in hypertensive patients was observed. Plasma 3,4 dihydroxyphenylacetic acid, a major metabolite of dopamine, fell from 1132 to 956 pg/ml in normal subjects and from 1242 to 807 pg/ml in hypertensives. No change in plasma adrenaline was found. At the same time, mean arterial pressure showed a significant decrease from 90 to 81 and from 132 to 111 mmHg in normotensive and hypertensive subjects, respectively. Bromocriptine also inhibited the increase in noradrena-line level that occurred when the subjects changed from the supine to the standing position. The inhibition was more evident in hypertensive subjects. It is suggested that the hypotensive effect of bromocriptine is mediated by the inhibition of noradrenaline release due to the stimulation of dopamine receptors on noradrenergic nerve terminals.

Effects of transdermal estrogen administration on peripheral vascular responsiveness in menopausal women

This study was designed to evaluate the peripheral vascular responses to acute estrogen replacement. According to a cross-over, double-blind study design, we randomized nine healthy postmenopausal women (time lapse from menopause to >1 year; mean age±SD 45.4±11.7 years) to treatment with transdermal patches of estradiol-17β or matched placebo. The estrogen patch was rated to assure a plasma concentration of substance of more than 100 pg/ml after 8–10 hours of treatment. Forearm blood flow (ml/100 ml/minute), local vascular resistance (mmHg/ml/100 ml/minute), venous volume (ml/100 ml), and venous compliance (ml/100 ml/mmHg) were measured in supine resting subjects by the straingauge venous occlusion plethysmography. Plasma concentration of norepinephrine (pg/ml) was quantified by HPLC-ED. Estradiol-17β produced increase in forearm blood flow and decrease in local vascular resistance. The drug reduced circulating norepinephrine concentrations. There were no significant changes in mean arterial pressure or heart rate. Venous volume and venous compliance were both enhanced by estrogen administration. The peripheral circulatory changes are attributed to a direct activity of estradiol-17β on arterial and venous wall and may in part reflect a modulation of estrogen on peripheral sympathetic tone.

Evidence for a dopaminergic control of sympathoadrenal catecholamine release

Abstract The existence and localization of a peripheral presynaptic dopamine (dopamine-2) receptor—whose activation by dopamine or its agonists inhibits the sympathetic neuronal release of norepinephrine—have been documented throughout the cardiovascular system. 1,2 However, the possible physiologic significance of dopamine-2 receptor in the control of circulatory function remains poorly understood. On the other hand, because of a common embryologic origin between the chromaffin cells of the adrenal medulla and peripheral sympathetic neurons, a dopaminergic modulation of the cholinergic-evoked catecholamine release from chromaffin cells might be postulated.

Echocardiographic assessment of aortic valve replacement with stentless porcine xenografts

Stentless porcine xenografts (SPXs) implanted in the aortic position have potential hemodynamic advantages over traditional valve prostheses because of the lack of a rigid stent. Twenty-four patients (mean age 59 years) who underwent aortic valve replacement with SPXs were studied by echocardiography early after and 26 +/- 10 months (range 8 to 40) after operation. Peak and mean gradients, as well as aortic valve area, did not change significantly from baseline (16.3 +/- 8 and 9.8 +/- 5.6 mm Hg, and 1.78 +/- 0.63 cm2, respectively) to follow-up study (12.5 +/- 5 and 7.7 +/- 3 mm Hg, and 1.8 +/- 0.65 cm2, respectively). At baseline, color flow Doppler imaging showed aortic valve regurgitation where the leaflets coapted centrally in 17 of 24 patients (trivial, n = 14; mild, n = 3). Besides the central leak, paravalvular regurgitation was seen in 4 patients (trivial, n = 3; mild, n = 1). At follow-up, 18 of 24 patients had aortic valve regurgitation (trivial, n = 11; mild, n = 6; and moderate, n = 1). New valvular regurgitation (graded as trivial, n = 2; mild, n = 2; and moderate, n = 1) was detected in 5 patients, and new paravalvular regurgitation (graded as mild) developed in 1 patient. Two patients underwent repeat operation for valve-related complications: (1) rupture of a valve cusp with acute pulmonary edema, and (2) fibrotic stenosis of the left coronary ostium with unstable angina. In conclusion, this study demonstrates good hemodynamic performance of the SPX in the aortic position.(ABSTRACT TRUNCATED AT 250 WORDS)