An updated clinical primer on large artery mechanics: implications of pulse waveform analysis and arterial tonometry

PURPOSE OF REVIEW

The use of pulse wave analysis with arterial tonometry has accelerated over the last year. Despite approval from the US Food and Drug Administration in 2001 on the use of generalized transfer function to generate the central (aortic) pressure wave from the radial waveform, this technique is still questioned. This review summarizes major findings on (a) value of arterial tonometry in determining indices of cardiovascular function, (b) use of these indices in outcome and drug studies, (c) relevance to major trials on blood pressure reduction.

RECENT FINDINGS

Pulse pressure has emerged as a better predictor of cardiac ischemic events than systolic, diastolic, and mean brachial pressure. Central systolic and pulse pressure and augmentation index have shown an even better relation with cardiovascular events and with outcomes. The claim by specific angiotensin-converting enzyme inhibitor and angiotensin receptor blocker drugs of their benefits "beyond blood pressure lowering" has been challenged on the basis of greater reduction in central and aortic pressure compared with brachial pressure measured by cuff sphygmomanometer, as shown by the pREterax in regression of Arterial Stiffness in a contrOlled double-bliNd study. Augmentation index is higher in hypertension, is inversely related to body height, and can be reduced by exercise. Augmentation index shows a linear relation with age up to 60 years. Regrettably, recent major trials such as the Comparison of Amlodipine versus Enalapril to Limit Occurrences of Thrombosis, Prevention of Events with Angiotensin Converting Enzyme Inhibition, and Valsartan Antihypertensive Long-term Use Evaluation studies have not included pulse wave analysis to distinguish the relative benefit of different drugs.

SUMMARY

Pulse wave analysis will assist in a better understanding of hypertension as well as in establishing the extent of cardiovascular disease and for monitoring therapy.

Influence of dobutamine on the variables of systemic haemodynamics, metabolism, and intestinal perfusion after cardiopulmonary resuscitation in the rat

BACKGROUND

Global left ventricular dysfunction after successful resuscitation from cardiac arrest may be treated successfully with dobutamine but the effects on intestinal perfusion are unknown.

METHODS

In 24 male Sprague-Dawley rats ventricular fibrillation was induced. After 4 min of untreated cardiac arrest, precordial chest compression was performed for 4 min; adrenaline (epinephrine) (90 microg kg(-1)) was injected, followed by defibrillation. Return of spontaneous circulation was achieved in 18 animals, which were allocated to receive saline 0.9% (control group, n = 6), dobutamine at 5 microg kg(-1) min(-1) (n = 6) or dobutamine at 10 microg kg(-1) min(-1) (n = 6). Measurements of haemodynamic variables and intestinal tonometer P(CO2) were made before induction of ventricular fibrillation and 15, 30, 60, and 120 min postresuscitation.

RESULTS

At 120 min postresuscitation, mean aortic pressure was 82 +/- 20, 104 +/- 19, and 113 +/- 15 mmHg for the control group, the dobutamine (5 microg kg(-1) min(-1)) group and the dobutamine (10 microg kg(-1) min(-1)) group (P < 0.05 for comparison of the dobutamine (10 microg kg(-1) min(-1)) group versus the control group). Respective abdominal aortic blood flow was 107 +/- 16, 133 +/- 49, and 145 +/- 18 ml min(-1) kg(-1) (P < 0.05 for comparison of the dobutamine (10 microg kg(-1) min(-1)) group versus the control group), and superior mesenteric artery blood flow was 25 +/- 9, 28 +/- 8, and 33 +/- 8 ml min(-1) kg(-1). Arterial lactate was significantly higher (P < 0.05) in the control group (2.3 +/- 0.6 mmol l(-1)) than in the dobutamine (5 microg kg(-1) min(-1)) group (1.6 +/- 0.3 mmol l(-1)) and dobutamine (10 microg kg(-1) min(-1)) group (1.5 +/- 0.3 mmol l(-1)). Tonometrically derived P(CO2) gap was highly elevated at 15 min of postresuscitation and returned to prearrest level at 120 min postresuscitation in all groups.

CONCLUSIONS

Dobutamine enhances the recovery of global haemodynamic and metabolic variables early after cardiac arrest.

Chronic coffee consumption has a detrimental effect on aortic stiffness and wave reflections

BACKGROUND

The effect of coffee consumption on the cardiovascular system is still an unresolved issue. Aortic stiffness and wave reflections are important prognosticators of cardiovascular disease risk. We have shown that caffeine acutely increases aortic stiffness and wave reflections.

OBJECTIVE

The objective was to investigate the effect of chronic coffee consumption on aortic stiffness and wave reflections.

DESIGN

This was a cross-sectional study of 228 healthy subjects: 141 men (x +/- SD: 41 +/- 8 y old) and 87 women (41 +/- 9 y old). Aortic stiffness was evaluated with carotid-femoral pulse wave velocity (PWV). Wave reflections were evaluated with augmentation index (AIx) and augmented pressure (AP) of the aortic pressure waveform with the use of high-fidelity pulse wave analysis. Coffee consumption was ascertained over 1 y with a food-frequency questionnaire.

RESULTS

A linear relation between coffee consumption and PWV, AIx, and AP was observed (P for trend < 0.05). Compared with the nonconsumption group, PWV was on average 13% higher, AIx was 2-fold higher, and AP was 2.4-fold higher (P < 0.01 for all) in the high-consumption group (>450 mL/d). The findings remained significant after control for confounders such as age, sex, smoking habits, body mass index, total and LDL cholesterol, triacylglycerols, blood glucose, mean blood pressure, and heart rate. The linear relation (P for trend < 0.05) observed between coffee consumption and arterial pressures was largely explained when the covariates were entered in the model.

CONCLUSIONS

Chronic coffee consumption exerts a detrimental effect on aortic stiffness and wave reflections, which may increase the risk of cardiovascular disease.

Modulation of growth hormone pulsatility by sex steroids in female goats

GH is secreted in a pulsatile manner, the pattern of which plays an important role in the regulation of growth and metabolism. Sex steroids are also known to participate in metabolic regulation. The present study was undertaken to elucidate the relationship between changes in GH pulsatility and metabolic transition during the estrous cycle in goats. From ovariectomized (OVX) and intact females in the early luteal, late luteal, and follicular phases, blood samples were taken every 15 min for 24 h, and plasma GH was measured by RIA. In the early luteal phase, GH was secreted in a distinct pulsatile manner, the pattern of which was similar to that in OVX goats, whereas the GH pulse frequency, amplitude, and area under the curve (AUC) were decreased in the late luteal phase. In the follicular phase, the GH pulse frequency, amplitude, and AUC were significantly larger than those in the late luteal phase. The regularity of GH pulsatility was highest and lowest in the early and late luteal phases, respectively. Both IGF-I and free fatty acid levels in the plasma were higher in the follicular than the luteal phase. Subcutaneous injection of estradiol to OVX goats increased the GH pulse amplitude and AUC, whereas the implantation of progesterone for 5 d decreased those parameters. These results suggest that the pulsatile pattern of GH secretion in goats varies with sex steroid levels and thereby affects IGF-I secretion and lipolysis during the estrous cycle.

Assessment of volume preload on uteroplacental blood flow during epidural anaesthesia for Caesarean section

BACKGROUND AND OBJECTIVE

Epidural and spinal anaesthesia are the preferred mode of anaesthesia for Caesarean section. Volume preloading is recommended to prevent maternal hypotension and a reduction in uteroplacental blood flow, although positive effects of volume preloading on maternal cardiac output and arterial pressure are debatable. Doppler measurements of the umbilical artery beyond deriving pulsatility indices are not routinely performed.

METHODS

After Institutional Review Board approval and written informed consent, 14 consecutiVe women with epidural anaesthesia for Caesarean section received either hydroxyethyl starch 500 mL or gelatine 500 mL. Haemodynamic variables monitored were maternal arterial pressure, maximal blood flow velocity and pulsatility indices of the uterine artery derived from Doppler measurements.

CONCLUSIONS

Maternal arterial pressure and pulsatility indices in both groups did not change from baseline after intravenous colloid infusion. However, uterine blood flow increased significantly in both groups. The effectiveness of volume preloading may therefore be better described by changes in maximum uterine blood flow velocity than by pulsatility indices or maternal arterial pressure.

Perioperative lower limb venous haemodynamics in patients under general anaesthesia †

BACKGROUND

This study prospectively determined the haemodynamic changes in the lower limb venous circulation during and shortly after elective abdominal surgery, performed under general anaesthesia.

METHODS

Ten females, aged 36-65 yr, ASA I or II, undergoing total abdominal hysterectomy had their peak, mean and minimum velocities, diameter, volume flow and venous pulsatility (peak-minimum/mean velocity) measured in the left popliteal vein on recumbency with duplex at: (i) baseline, (ii) 15 min after induction, (iii) during surgery, and (iv) in recovery 30 min after extubation. Anaesthesia was induced with fentanyl and propofol, paralysis with vecuronium, maintenance with isoflurane in nitrous oxide 66%, and analgesia with morphine. Results are presented as percentage difference from baseline mean value. The Friedman and Wilcoxon([corrected(*)]) tests were applied.

RESULTS

Mean velocity decreased by 23.6% during surgery and by 34.6% in recovery (P<0.05(*)). Minimum velocity was decreased by 56% during surgery and by 78% in recovery (P<0.05). The volume flow decreased by 26% during surgery, and by 54.4% in recovery (P<0.001). Diameter and peak velocity changed little at surgery and recovery (P>0.2). In contrast, the pulsatility increased by 30% on induction, 83% on surgery and 109% in recovery (P<0.05). Compared with baseline, haemodynamic changes on induction were small (P>0.1(*)).

CONCLUSIONS

A significant decrease in the volume flow, mean and minimum velocities was noted during and immediately after elective total abdominal hysterectomy under general anaesthesia in ASA I and II patients. Flow changes in early recovery mirrored or enhanced those noted intraoperatively. Despite venous flow attenuation, haemodynamic readjustments produced a significant and progressive enhancement of venous flow pulsatility during the course of the procedure.

Benefits from angiotensin-converting enzyme inhibitor ‘beyond blood pressure lowering’: beyond blood pressure or beyond the brachial artery?

OBJECTIVE

The substantial benefits of ramipril over conventional therapy in high-risk patients are not always associated with clinically significant differences in brachial arterial pressure, and largely remain unexplained. We undertook this acute study to establish the magnitude of and reason for different acute effects of ramipril and atenolol on arterial pressure.

METHODS

We enrolled 30 patients, who took 10 mg ramipril, 100 mg atenolol, and placebo at intervals of > or = 7 days, in a randomized, double-blind, placebo-controlled trial. After baseline, measurements were taken at 30-60 min intervals for 5 h, and comprised cuff brachial pressure, radial artery tonometry with generation of central aortic pressure, and pulse wave velocity for aorta, upper limb and lower limb arteries.

RESULTS

Both ramipril and atenolol reduced arterial pressure, and the diastolic pressure fall was similar in the aorta and brachial artery, but the systolic pressure fall for ramipril was greater than for atenolol (by 5.2 mmHg, P < 0.0001) in the aorta compared with the brachial artery. The aortic systolic pressure difference with ramipril in comparison with atenolol was accompanied by an absolute difference of 10.7% (P < 0.0001) in the augmentation index, denoting a reduction in peripheral wave reflection by ramipril. The aortic pulse wave velocity fell to a similar degree with ramipril in comparison with atenolol, but fell to a greater degree (1.35 and 0.44 m/s, respectively, P < 0.0001 for both) in muscular arteries of the lower and upper limbs.

CONCLUSION

A greater (average, 5.2 mmHg) decrease in aortic systolic pressure caused by ramipril may explain the greater benefit of ramipril over atenolol. The difference is attributable to decreased stiffness of peripheral arteries and a reduction in wave reflection.

Smoking and caffeine have a synergistic detrimental effect on aortic stiffness and wave reflections

OBJECTIVES

We investigated the acute and chronic combined effect of cigarette smoking and caffeine intake on aortic stiffness and wave reflections.

BACKGROUND

We have shown that smoking and caffeine separately increase arterial stiffness. Aortic stiffness and wave reflections are important determinants of the efficient performance of the cardiovascular system and prognosticators of cardiovascular risk.

METHODS

The acute effects of smoking (one cigarette), caffeine (200 mg, equivalent to 2 cups of coffee), and smoking plus caffeine were studied in 24 healthy subjects according to a randomized, placebo- and sham procedure-controlled crossover design. The chronic effect of smoking and caffeine was studied in a population study that enrolled 160 healthy subjects.

RESULTS

Acute study: there was a significant interaction between caffeine and smoking with regard to pulse-wave velocity (p < 0.01) and augmentation index (p < 0.05). When smoking followed caffeine intake, pulse-wave velocity and augmentation index increased further by 0.52 m/s and 13.4%, respectively, reaching a total of 0.85 m/s and 17.4%, 0.17 m/s and 9.2% in excess of the mere sum of caffeine effect (0.33 m/s and 4%) alone and smoking effect alone (0.35 m/s and 4.2%). Population study: there was a significant interaction of chronic coffee consumption and smoking regarding pulse-wave velocity (p < 0.05) and augmentation index (p = 0.001).

CONCLUSIONS

The present study shows, for the first time, that when smoking and caffeine intake are combined, they interact and exert a synergistic, unfavorable effect on aortic stiffness and wave reflections on both an acute and chronic basis.

Smoking and caffeine have a synergistic detrimental effect on aortic stiffness and wave reflections

OBJECTIVES

We investigated the acute and chronic combined effect of cigarette smoking and caffeine intake on aortic stiffness and wave reflections.

BACKGROUND

We have shown that smoking and caffeine separately increase arterial stiffness. Aortic stiffness and wave reflections are important determinants of the efficient performance of the cardiovascular system and prognosticators of cardiovascular risk.

METHODS

The acute effects of smoking (one cigarette), caffeine (200 mg, equivalent to 2 cups of coffee), and smoking plus caffeine were studied in 24 healthy subjects according to a randomized, placebo- and sham procedure-controlled crossover design. The chronic effect of smoking and caffeine was studied in a population study that enrolled 160 healthy subjects.

RESULTS

Acute study: there was a significant interaction between caffeine and smoking with regard to pulse-wave velocity (p < 0.01) and augmentation index (p < 0.05). When smoking followed caffeine intake, pulse-wave velocity and augmentation index increased further by 0.52 m/s and 13.4%, respectively, reaching a total of 0.85 m/s and 17.4%, 0.17 m/s and 9.2% in excess of the mere sum of caffeine effect (0.33 m/s and 4%) alone and smoking effect alone (0.35 m/s and 4.2%). Population study: there was a significant interaction of chronic coffee consumption and smoking regarding pulse-wave velocity (p < 0.05) and augmentation index (p = 0.001).

CONCLUSIONS

The present study shows, for the first time, that when smoking and caffeine intake are combined, they interact and exert a synergistic, unfavorable effect on aortic stiffness and wave reflections on both an acute and chronic basis.

A randomized trial of plasma volume expansion in hypertensive disorders of pregnancy: influence on the pulsatility indices of the fetal umbilical artery and middle cerebral artery

OBJECTIVE

The purpose of this study was to investigate the effect of plasma volume expansion on the pulsatility indices of the fetal umbilical and middle cerebral arteries.

STUDY DESIGN

Two hundred sixteen patients with severe preeclampsia, HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome, eclampsia, hypertension-related fetal growth restriction, and gestational ages between 24 and 34 completed weeks of gestation were assigned randomly for temporizing treatment with plasma volume expansion (n = 111 patients; 250 mL hydroxyethyl starch 6% twice daily in 4 hours, and NaCl 0.9% between doses of hydroxyethyl starch and with intravenous medication) or without plasma volume expansion (n = 105; only NaCl 0.9% when necessary with medication). Measurements of the pulsatility index of the umbilical and middle cerebral arteries were performed at admission, after 16 to 48 hours, 60 to 120 hours, and 7 to 11 days.

RESULTS

Median gestational age was 30 weeks in both groups. Infused volumes of plasma volume expansion in the treatment group (total median, 813 mL/d) were associated with a significant decrease of hemoglobin concentration. Changes from baseline measurements of the umbilical and middle cerebral arteries were not different between the groups nor within subgroups during the first 7 to 11 days.

CONCLUSION

Plasma volume expansion did not influence the pulsatility indices of the umbilical and middle cerebral arteries.

Effects of sildenafil on ocular perfusion demonstrated by color Doppler ultrasonography

The aim of this study was to investigate the effects of sildenafil on ocular hemodynamics by color Doppler ultrasonography (CDU). In all, 38 patients with erectile dysfunction diagnosed by International Index of Erectile Function (IIEF) and Sexual Health Inventory of Men (SHIM) scores were included into the study. After taking 100 mg of oral sildenafil citrate, all patients underwent CDU examination of central retinal artery at 60 and 75 min and CDU examination of cavernosal artery at 20, 60 and 75 min. All of the side effects during and after the test were also recorded. The mean cavernous artery peak systolic flow velocity increased significantly after sildenafil. However, no significant change was determined in central retinal artery flow parameters including peak systolic flow velocity, end-diastolic flow velocity, resistive index, pulsatility index, volume and diameter. Five patients experienced ocular side effects. No significant change was observed in retinal artery CDU measurements of patients having ocular side effects. Sildenafil has no effect on ocular hemodynamics on the basis of CDU. Ocular side effects may be the result of other changes in retinal photoreceptors rather than the ocular circulation.

Atorvastatin reduces arterial stiffness in patients with rheumatoid arthritis

BACKGROUND

Chronic systemic inflammation may contribute to accelerated atherosclerosis and increased arterial stiffness in patients with rheumatoid arthritis (RA). In addition to lowering cholesterol, statins have immunomodulatory effects which may be especially beneficial in patients with RA who have systemic immune activation.

OBJECTIVE

To investigate the effect of atorvastatin on the augmentation index (AIx: a measure of arterial stiffness) and systemic inflammation in RA.

METHODS

29 patients with RA (mean (SD) age 55 (13) years) with moderately active disease of long duration were studied. AIx, lipid levels, serum inflammatory markers, and disease activity score were measured before and after 12 weeks of atorvastatin 20 mg daily.

RESULTS

AIx improved significantly from 34.1 (11.6)% to 29.9 (11)% (p = 0.0002), with the greatest improvements in AIx occurring in those subjects with the highest disease activity scores (r = -0.5, p = 0.007). Total and LDL cholesterol were reduced from 5.5 (0.9) to 3.9 (0.7) mmol/l and 3.3 (0.8) to 1.9 (0.6) mmol/l, respectively (p = 0.0001). Serum inflammatory markers remained unchanged during the study.

CONCLUSIONS

Atorvastatin significantly reduced arterial stiffness in patients with RA. The greatest improvements were seen in patients with more active disease, suggesting that, in addition to the beneficial effects of cholesterol reduction, immune modulation may contribute to the cardioprotective effect of statins.

Effect of garlic (Allium sativum) powder tablets on serum lipids, blood pressure and arterial stiffness in normo-lipidaemic volunteers: a randomised, double-blind, placebo-controlled trial

Recent studies have cast doubt on the proposed lipid-lowering and blood pressure-lowering effects of garlic. We tested the effect of dried garlic (Allium sativum) powder on blood lipids, blood pressure and arterial stiffness in a 12-week randomised, double-blind, placebo-controlled trial. Seventy-five healthy, normo-lipidaemic volunteers (men and women aged 40-60 years) were assigned to dried garlic powder tablets (10.8 mg alliin (3-(2-propenylsulfinyl)-L-alanine)/d, corresponding to about three garlic cloves) or placebo. Sixty-two subjects were eligible for the per-protocol analysis. The primary outcome measure was serum total cholesterol concentration. Secondary outcome measures were LDL-cholesterol, HDL-cholesterol and triacylglycerol concentrations, blood pressure and arterial stiffness (assessed by pulse wave velocity). No significant differences between the garlic and placebo groups were detected for any of the outcome measures. However, garlic powder was associated with a near-significant decrease (12 %) in triacylglycerol concentration (P=0.07). In conclusion, garlic powder tablets have no clinically relevant lipid-lowering and blood pressure-lowering effects in middle-aged, normo-lipidaemic individuals. The putative anti-atherosclerotic effect of garlic may be linked to risk markers other than blood lipids.

Beta-blocking therapy in patients with the Marfan syndrome and entire aortic replacement

OBJECTIVE

Beta-blocking therapy is the standard therapy in non-operated Marfan patients, however its efficacy after entire aortic replacement is unknown. The aim of this study was to describe the influence of (nearly) entire aortic replacement and beta-blocking therapy on blood pressure and wave reflections in Marfan patients.

METHODS

Four Marfan patients (mean age 31+/-3 years) and 8 age matched control subjects were studied. Blood pressure and wave reflections (reflection coefficient and augmentation index) were studied by means of magnetic resonance imaging, continuous non-invasive blood pressure measurements and applanation tonometry. Patients were studied with atenolol, labetalol and without beta-blocking therapy.

RESULTS

In Marfan patients, aortic systolic pressure (129+/-13 vs 114+/-10 mmHg), pulse pressure (58+/-13 vs 40+/-5 mmHg), wave speed (11+/-3 vs 4+/-0.4 m s(-1)) and reflection coefficient (65+/-22 vs 41+/-5%) were significantly increased compared to controls. There was no difference in aortic pressure between various medications in Marfan patients (atenolol 129/76 mmHg, labetalol 121/75 mmHg and without beta-blocking therapy 129/71 mmHg). Higher reflection coefficients were seen in patients with atenolol compared to discontinued medication (73+/-18 vs 65+/-22%), and also the augmentation index was higher with atenolol compared to labetalol and discontinued medication (24+/-22 vs 17+/-17 vs 22+/-22%, respectively).

CONCLUSION

Our results describe increased pulse pressure, systolic pressure, wave speed and wave reflections in four Marfan patients after entire aortic replacement. The use of atenolol or labetalol did not decrease aortic pressure and with atenolol increased wave reflections were observed. Therefore, the beneficial effect of atenolol in these patients is doubtful.

Validity of pulse pressure and augmentation index as surrogate measures of arterial stiffness during beta-adrenergic stimulation

OBJECTIVE

Increased arterial stiffness is a determinant of cardiovascular mortality. Pulse wave velocity (PWV) is a direct measure of arterial stiffness. Aortic augmentation index (AI) and pulse pressure (PP) are surrogate measures of arterial stiffness. Both PWV, AI and PP increase with cardiovascular risk factors. The aim of this study was to test the validity of AI and PP as surrogate measures of arterial stiffness compared with PWV, during beta-adrenergic stimulation with Isoprenaline (Iso).

DESIGN AND METHODS

A total of 41 healthy volunteers entered a randomized, double-blind, placebo-controlled, cross-over study. In random order, subjects were given intravenous infusion in equal volume of Iso 8 microg/kg per min (dissolved in glucose 5%) and placebo (glucose 5%). A wash-out period of 25 min was observed between the infusions. Measurements included blood pressure (BP), heart rate (HR), PWV, and AI. PWV were determined using complior (Complior, Artech-Medical, Paris, France). AI and aortic PP were obtained from pulse wave analysis of radial applanation tonometry, using transfer function (SphygmoCor Windows software).

RESULTS

Baseline AI increased (P < 0.05) with aging, a lower height and a larger diastolic BP (DBP). Iso increased (P < 0.0001) HR, brachial SBP, brachial and aortic PP as compared with placebo. In contrast, Iso decreased (P < 0.05) AI, brachial DBP, peripheral PWV, but not aortic PWV. Decrease of AI induced by Iso was not related to PWV. In stepwise multiple regression changes in HR, brachial SBP and DBP were independent determinants of AI response to Iso (r = 0.78, P < 0.0001).

CONCLUSIONS

Our findings show that AI and PP fail as surrogate measures of arterial stiffness during beta-adrenergic stimulation.

Long-term effects of statins on arterial pressure and stiffness of hypertensives

Although lowering blood pressure (BP) reduces aortic stiffness, achieving the recommended BP goal can be difficult. Recent studies have shown that short-term use of statins can reduce BP significantly. To determine the long-term effects of statins on BP and aortic stiffness, a single-blind randomized prospective study was performed on 85 hyperlipidaemic hypertensive patients whose BP was insufficiently controlled by antihypertensive therapy. Every 3 months, aortic stiffness was assessed by measuring pulse wave velocity (PWV). Patients were randomly allocated to groups treated with pravastatin, simvastatin, fluvastatin, or a nonstatin antihyperlipidaemic drug. No significant differences in patient characteristics, kinds of antihypertensive drugs, BP, ankle brachial index, PWV, or serum lipid, creatinine, or C-reactive protein levels were found between the four groups at the start of the study. During the 12-month treatment period, PWV did not change in the pravastatin group or nonstatin group, but it was transiently reduced in the simvastatin group and significantly decreased in the fluvastatin group, even though the doses of the statins used in this study were lower than the usually prescribed dose. All four antihyperlipidaemic drugs significantly decreased serum cholesterol levels without affecting BP, ankle brachial index, or serum triglyceride levels. The C-reactive protein serum levels decreased significantly in the three statin groups but not in the nonstatin group. These results suggest that long-term use of fluvastatin by hyperlipidaemic hypertensive patients is associated with a significant reduction in aortic stiffness without any effect on BP.

Selective reduction of heart rate by ivabradine

BACKGROUND

The heart rate (HR) reduction obtained by ivabradine is associated in rats with a decrease in diastolic blood pressure (DBP) and mean blood pressure (MBP), and with an increased pulsatile carotid arterial diameter.

OBJECTIVE

To determine, in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats, whether acute reductions of the HR in response to ivabradine induced changes in the carotid visco-elastic behavior, as assessed by echo-tracking techniques.

METHODS

The hysteresis of the carotid diameter/pressure curve was used to determine the dissipated energy per cardiac cycle, a classical index of arterial viscosity. Four doses of 1 mg/kg intravenous ivabradine were repeated in anesthetized rats to obtain subsequent HR reductions.

RESULTS

In WKY, repeated administration of ivabradine produced reduction of MBP, DBP and HR, without change of systolic blood pressure (SBP). In SHR, ivabradine produced a higher reduction in DBP, SBP and HR than in WKY rats, but the increase in pulse pressure was similar in both strains. In SHR and WKY rats, ivabradine did not modify the incremental elastic modulus-stress curves, and shifted the distensibility-pressure curves through changes in blood pressure, indicating no modification in isobaric carotid stiffness. In both strains, ivabradine produced an identical increase of the energy dissipated per cardiac cycle.

CONCLUSION

In WKY rats and SHR, acute ivabradine reduces MBP and DBP and increases pulse pressure, but without change in arterial stiffness. In both strains, the HR reduction due to ivabradine induces an identical increase of the energy dissipation of the arterial wall.

A Randomized, Double-Blind, Placebo-Controlled Clinical Trial of the Chinese Herbal Medicine “Ba Wei Di Huang Wan” in the Treatment of Dementia

OBJECTIVES

To evaluate whether a traditional Chinese herbal medicine, ba wei di huang wan (BDW), improves cognitive and physical functioning in dementia patients.

DESIGN

An 8-week randomized, double-blind, placebo-controlled trial.

SETTING

Long-term-care facility in Japan.

PARTICIPANTS

Thirty-three patients with mild to severe dementia (7 men and 26 women; mean age +/- standard deviation=84.4 +/- 7.8) were recruited and enrolled from May 2002 through September 2002.

INTERVENTION

Participants were randomly assigned to the active drug (BDW) group (n=16) or the placebo group (n=17) and treated for 8 weeks.

MEASUREMENT

Cognitive function and activities of daily living (ADLs); palsatility index.

RESULTS

After the trial, cognitive function as assessed using the Mini-Mental State Examination (MMSE) significantly improved from 13.5 +/- 8.5 to 16.3 +/- 7.7 (P<.01, 95% confidence interval (CI)=-4.1 to -1.4) in the BDW group. The ADL score in the Barthel Index also significantly changed, from 61.8 +/- 34.6 to 78.9 +/- 21.1 (P<.01, 95% CI=-26.2 to -7.9). In contrast, MMSE and Barthel Index scores of the placebo group showed no significant change. Eight weeks after the end of the administration, MMSE and Barthel Index scores of the BDW group declined to the baseline level. The pulsatility index in the internal carotid artery as measured using Doppler sonography significantly decreased in the BDW group (2.5 +/- 1.7 to 1.9 +/- 0.5, P<.05) but not in the placebo group.

CONCLUSION

These results argue the benefits of BDW in the treatment of dementia.

[What's new in ophthalmic anaesthesia?]

In the past few years, there have been many changes in ophthalmic anaesthesia. Application of drugs in general anaesthesia with excellent controllability enhances patient safety and allows a more efficient OR-management. Regional anaesthesia is gaining widespread use for ophthalmic surgery, especially topical anaesthesia for cataract surgery. Patients for ophthalmic surgery concomitantly often display high age and a high level of co-morbidity and, therefore, belong to the anaesthesiological risk groups ASA III-IV. Life-threatening adverse events including cardiovascular depression are associated with general and regional anaesthesia. Intervention by anaesthesiologists is frequently required for treatment of hypertension or dysrhythmias, and sedation. Thus, monitored anaesthesia care ("standby") is justified. Drugs applied for regional and general anaesthesia may change intraocular pressure. There are a lot of publications about the impact of anaesthesia on intraocular pressure (IOD), however, few on the effects of anaesthesia on pulsatile ocular blood flow. it has to be kept in mind that the effects of anaesthesia on intra-ocular pressure and pulsatile ocular blood flow may diverge. To avoid an increase of the IOD, especially during anaesthesia induction, drugs, such as succinylcholin, rocuronium and opiates, in particular remifentanil, can be applied. In addition, the use of the laryngeal mask may be advantageous compared to general anaesthesia associated with laryngoscopic tracheal intubation. The management of patients treated with anticoagulants and antiplatelet agents, has to be taken on the balance of risks. There are risks not only in continuing therapy, but also in discontinuing it perioperatively. Postoperative nausea and vomiting (PONV) remains a distressing and common problem after strabismus repair in particular in children. The incidence of PONV depends on the type of ophthalmic surgery and drugs applied. To reduce PONV in ophthalmic surgery, application of long-lasting opiates should be avoided, and non-opiate analgesics and, depending on the kind of operation, antiemetic prophylactics are recommended.

Tamoxifen improves endothelial function and reduces carotid intima-media thickness in postmenopausal women

BACKGROUND

Tamoxifen is a selective estrogen-receptor modulator shown to improve several cardiovascular risk factors in postmenopausal women with breast cancer. In animal studies tamoxifen inhibits the progression of atherosclerosis. Although the presence of a history with tamoxifen treatment is related to a lower intima-media thickness (IMT) of the common carotid artery, data from controlled follow-up studies are lacking to support this observation.

METHODS

We examined 14 postmenopausal women with early stage breast cancer with indication for tamoxifen treatment (20 mg/d) and 13 healthy postmenopausal women. Flow-mediated dilatation (FMD) of the brachial artery, combined carotid IMT, and aortic pulse wave were measured before and 6 months after treatment in the tamoxifen group and at the same times in the control group.

RESULTS

FMD and IMT were significantly increased and decreased, respectively, in the treatment group compared to the control group (FMD: +2.2% +/- 0.9% vs +0.085% +/- 1%, P =.012; IMT: -0.088 +/- 0.03 mm vs +0.04 +/- 0.03 mm, P =.018, mean +/- standard error of the mean, treatment vs control group). These differences remained significant even when adjusted for age, duration of menopause, and cardiovascular risk factors. Low-density lipoprotein cholesterol was also significantly reduced after tamoxifen treatment.

CONCLUSIONS

Tamoxifen treatment slows the progression of atherosclerosis in postmenopausal women with breast cancer as assessed by changes in carotid IMT. An improvement in endothelial function and blood lipid profile may be the reason for this beneficial effect.

Phentolamine administration increases blood S100B protein levels in pediatric open-heart surgery patients

AIM

Phentolamine administration during open-heart surgery shortens the cooling and rewarming phases of cardiopulmonary bypass (CPB) and hastens weaning from mechanical ventilation and extubation. Data on the effects of phentolamine on cerebral circulation and function in this setting are lacking. This study reports the cerebral effects of phentolamine using blood S100B protein levels and the middle cerebral artery pulsatility index (MCA PI).

METHODS

Sixty pediatric patients undergoing congenital heart disease repair were randomly assigned to receive either phentolamine 0.2 mg kg(-1) i.v. (n = 30) or placebo (n = 30) before the cooling and rewarming phases of CPB. Samples for S100B measurement were collected at seven predetermined time-points before, during and after surgery. MCA PI values were recorded at the same times as sampling.

RESULTS

S100B blood levels were higher in the phentolamine-treated group than in controls after rewarming (3.53 +/- 1.88 vs 1.58 +/- 0.53 microg l(-1); p < 0.001), remained persistently higher at the end of surgery (2.95 +/- 0.91 vs 0.79 +/- 0.21 microg l(-1); p < 0.001) and returned to normal ranges 12 h later than in the placebo group (p > 0.05). MCA PI values were also significantly higher at the end of surgery in the phentolamine-treated group (1.83 +/- 0.50 vs 1.22 +/- 0.34; p < 0.01). Cooling and rewarming times were shorter in the phentolamine-treated group (p < 0.01, for all).

CONCLUSION

Despite improved peripheral vasodilatation and perfusion, phentolamine administration in pediatric open-heart surgery is correlated with increased cerebrovascular resistance and brain damage.

Effect of antenatal glucocorticoid therapy on arterial and venous blood flow velocity waveforms in severely growth-restricted fetuses

OBJECTIVE

To study the effects of antenatal glucocorticoid (betamethasone) therapy on blood flow velocity waveform patterns in the umbilical artery (UA), middle cerebral artery (MCA) and ductus venosus (DV) in severely intrauterine growth-restricted (IUGR) fetuses.

METHODS

Fifty-five severely IUGR fetuses at 24-34 weeks of gestation were included in the study. The effect of antenatal glucocorticoid administration on Doppler findings in the UA, MCA and DV was studied using two statistical approaches, namely paired sample analysis and multilevel analysis.

RESULTS

There were no effects of betamethasone on the pulsatility index (PI) of the vessels studied. The only changes noticed during the 14 days of observation were a gradual decrease of PI in the MCA, an increase in the UA-PI/MCA-PI ratio and an increase in the DV-PI. These changes with time may be explained by a progressive and gradual deterioration of the fetal condition.

CONCLUSION

Antenatal glucocorticoids (betamethasone) do not affect fetal Doppler waveform patterns of the UA, MCA and DV in severely IUGR fetuses.

Hormone therapy and ophthalmic artery blood flow changes in women with primary open-angle glaucoma

OBJECTIVE

To compare the effects of hormone therapy (HT) on plasma viscosity and Doppler flow parameters in normal, healthy, postmenopausal women and in women with normal-tension and chronic, open-angle glaucoma.

DESIGN

Eight postmenopausal women with glaucoma (group I) and 15 controls (group II) were given HT. The duration of the study was 6 months, and the women were examined in basal condition and at the end of the treatment. All women underwent ultrasonographic evaluation of pelvic organs and color Doppler analysis of uterine, internal carotid, and ophthalmic arteries. Also, plasma viscosity was assayed.

RESULTS

The ultrasonographic analysis showed that none of the women presented with irregular endometrial echoes, polyps, or intracavitary fluid. In addition, endometrial thickness never exceeded the normal range (5 mm). Plasma viscosity and Doppler parameters significantly improved during therapy. However, the ophthalmic artery mean improvements of pulsatility index (-43% v -28%; P = 0.001), peak systolic blood flow velocity (+35% v +24%; P = 0.026), and time-averaged maximum velocity (+44% v +32%; P = 0.031) were significantly more evident in the control group than in the glaucoma group.

CONCLUSIONS

Although, in people with glaucoma, vasospasm can increase the risk of visual loss by inducing a retrobulbar blood flow reduction, HT seems to beneficially affect the ocular vascularization.

The effect of adrenomedullin, amylin fragment 8-37 and calcitonin gene-related peptide on contractile force, heart rate and coronary perfusion pressure in isolated rat hearts

The effect of human adrenomedullin, human amylin fragment 8-37 (amylin 8-37) and rat calcitonin gene-related peptide (CGRP) on contractile force, heart rate and coronary perfusion pressure has been investigated in the isolated perfused rat hearts. Adrenomedullin (2x10(-10), 2x10(-9) and 2x10(-8) M) produced a significant decrease in contractile force and perfusion pressure, but only the peptide caused a decline in heart rate at the highest dose. Amylin (10(-9), 10(-8) and 10(-7) M) significantly increased and then decreased contractile force. Two doses of amylin (10(-8) and 10(-7) M) induced a significant increase in heart rate, however amylin did not change perfusion pressure in all the doses used. Rat alpha CGRP (10(-8), 10(-7) and 10(-6) M) evoked a slight decline in contractile force following a significant increase in contractile force induced by the peptide. CGRP in all the doses raised heart rate and lowered perfusion pressure. Our results suggest that adrenomedullin has negative inotropic, negative chronotropic and coronary vasodilator actions. Amylin produces a biphasic inotropic effect and evokes a positive chronotropy. CGRP causes positive inotropic, positive chronotropic and vasodilatory effects in isolated rat hearts.

[Impact of HRT on the arterial carotid vascular tree]

Hormone replacement therapy (HRT) and arterial impact, this is a controversial subject since it is a large field that needs weeding, a theme in which new questions are raised by the cross-results of various studies conducted, and in which doubt is perhaps one of, or even the only, certitude that all the various specialists agree on. In this controversial climate, we feel that three important points should be underlined: the American studies, however reliable they may be, have been conducted with conjugated estrogens and the generalisation to the results of other types of hormones such as those prescribed in Europe is perhaps a little hasty; other factors of risk should be taken into consideration in the eventual potentialisation of the risk induced by such treatment; the venous and arterial vascular risks are not based on the same physiopathological mechanisms. Hence the increased risk in one or the other network system should perhaps not be amalgamated either.