Hemodynamic changes associated with reduction in total cholesterol by treatment with the HMG-CoA reductase inhibitor pravastatin

Arterial Stiffness and its Impact on Cardiovascular Health

PURPOSE OF REVIEW

Cardiovascular diseases are the leading cause of mortality globally. Identifying patients at risk is important to initiate preventive strategies. Over the last few decades, the role of the endothelium and its impact on arterial stiffness have been recognised as playing a pivotal role in cardiovascular disease. This review will focus on the effect of arterial stiffness in different patient cohorts with regard to cardiovascular morbidity and mortality, as well as its use in clinical practice.

RECENT FINDINGS

Arterial stiffness is associated with a range of cardiovascular risk factors and is an independent predictor of cardiovascular mortality. The gold standard for evaluating arterial stiffness is pulse wave velocity. Recently, cardio-ankle vascular index has been implemented as an easy and highly reproducible measure of arterial stiffness. Moreover, certain pharmacologic agents may modify arterial stiffness and alter progression of cardiovascular disease. The endothelium plays an important role in cardiovascular disease. Implementing assessment of arterial stiffness in clinical practice will improve stratification of patients at risk of cardiovascular disease and help modify disease progression.

The Importance of Arterial Stiffness Assessment in Patients with Familial Hypercholesterolemia

Cardiovascular diseases are still the leading cause of mortality due to increased atherosclerosis worldwide. In the background of accelerated atherosclerosis, the most important risk factors include hypertension, age, male gender, hereditary predisposition, diabetes, obesity, smoking and lipid metabolism disorder. Arterial stiffness is a firmly established, independent predictor of cardiovascular risk. Patients with familial hypercholesterolemia are at very high cardiovascular risk. Non-invasive measurement of arterial stiffness is suitable for screening vascular dysfunction at subclinical stage in this severe inherited disorder. Some former studies found stiffer arteries in patients with familial hypercholesterolemia compared to healthy controls, while statin treatment has a beneficial effect on it. If conventional drug therapy fails in patients with severe familial hypercholesterolemia, PCSK9 inhibitor therapy should be administered; if these agents are not available, performing selective LDL apheresis could be considered. The impact of recent therapeutic approaches on vascular stiffness is not widely studied yet, even though the degree of accelerated athero and arteriosclerosis correlates with cardiovascular risk. The authors provide an overview of the diagnosis of familial hypercholesterolemia and the findings of studies on arterial dysfunction in patients with familial hypercholesterolemia, in addition to presenting the latest therapeutic options and their effects on arterial elasticity parameters.

Beneficial Effect of Statin Therapy on Arterial Stiffness

Arterial stiffness describes the increased rigidity of the arterial wall that occurs as a consequence of biological aging and several diseases. Numerous studies have demonstrated that parameters to assess arterial stiffness, especially pulse-wave velocity, are predictive of those individuals that will suffer cardiovascular morbidity and mortality. Statin therapy may be a pharmacological strategy to improve arterial elasticity. It has been shown that the positive benefits of statin therapy on cardiovascular disease is attributable not only to their lipid-lowering capacity but also to various pleiotropic effects, such as their anti-inflammatory, antiproliferative, antioxidant, and antithrombotic properties. Additionally, statins reduce endothelial dysfunction, improve vascular and myocardial remodeling, and stabilize atherosclerotic plaque. The aim of the present review was to summarize the evidence from human studies showing the effects of statins on arterial stiffness.

Effect of statin therapy on pulse wave velocity: A meta-analysis of randomized controlled trials

BACKGROUND AND OBJECTIVE

Arterial stiffness (AS) is an independent cardiovascular risk factor. A number of studies have reported a beneficial role of statins on AS albeit with controversial results, in addition to their effects on lipid profile. Therefore, we carried out a meta-analysis of the available randomized controlled trials assessing the effects of statin therapy on AS, in the attempt to reach more definitive conclusions.

METHODS

A systematic search of the on-line databases available up to March 2017 was conducted, including intervention studies reporting AS expressed by carotid-femoral pulse wave velocity (PWV), as difference between the effects of treatment with or without statins. For each study, mean difference (MD) and 95% confidence intervals (CI) were pooled using a random effect model.

RESULTS

Eleven studies met the pre-defined inclusion criteria, for a total of 573 participants and 2-144 weeks' intervention time. In the pooled analysis, statin therapy was associated with a -6.8% (95% C.I.: -11.7 to -1.8) reduction in PWV. There was significant heterogeneity among studies (I² = 96%); none of the study characteristics seems to have influenced the effect of statin use on PWV.

CONCLUSIONS

The results of this meta-analysis suggest that statin therapy reduces AS. This effect appears to be at least in part independent of the changes in blood pressure and lipid profile.

Arterial wave reflection is associated with severity of extracoronary atherosclerosis in patients with coronary artery disease

BACKGROUND

Arterial wave reflection is a major determinant of left ventricular function, coronary perfusion and cardiovascular risk. We investigated whether arterial wave reflection may detect atherosclerosis of peripheral arteries in patients with documented coronary artery disease (CAD).

METHODS

Radial artery applanation tonometry and pulse wave analysis was performed in 184 patients with documented CAD at coronary angiography; central blood pressures and augmentation index (AI) were measured. Ankle-brachial (ABI) index and intima-media thickness (IMT) were used as indices of atherosclerosis of the lower limbs and the carotid arteries respectively.

RESULTS

Patients with abnormal IMT (> 0.7 mm, first tertile) or ABI (< 0.94, first tertile) had higher AI than patients with lower IMT or higher ABI (24 +/- 17 versus 17 +/- 16% and 23 +/- 18 versus 18 +/- 13%, respectively, P < 0.05). In multivariate analysis, increasing AI was associated with age, female gender, heart rate, mean blood pressure, hyperlipidaemia, and use of statins (regression coefficient (beta) = 0.50, beta = 0.15, beta = -0.60, beta = 0.23, beta = 0.16 and beta = -0.14, respectively, P < 0.05). Increasing AI was associated with an adjusted-odds ratio of 1.035 [95% confidence interval (CI), 1.005-1.066], P = 0.02 for an abnormal IMT and of 1.08 (95% CI, 1.024-1.146), P = 0.005 for ABI after adjustment for age, gender, heart rate, height, blood pressure, atherosclerotic risk factors, obesity and medication. No relation was found between AI and Gensini score or for the number of diseased coronary vessels.

CONCLUSION

Augmentation index is a marker of extensive extracoronary atherosclerosis in patients with CAD.

Association of brachial-ankle pulse wave velocity with cardiovascular risk factors in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is associated with premature atherosclerosis. Increasing arterial stiffness is closely associated with atherosclerotic cardiovascular diseases, and pulse wave velocity (PWV) is considered to be an indicator of arterial stiffness. The objective of this study was to identify the relationship between brachial-ankle pulse wave velocity (baPWV) and cardiovascular risk factors in patients with SLE. Age, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting blood glucose (FBS), plasma lipid profile, plasma homocysteine, thiobarbituric acid reactive substances (TBARS), baPWV, ankle-brachial index (ABI), and SLE-related factors were determined in a total of 83 SLE patients (12 males and 71 females). All SLE patients were further classified into two subgroups according to baPWV value (baPWV 1400 cm/s, n 37 versus baPWV 1400 cm/s, n 46). The mean baPWV value of studied SLE patients was 1520 381 cm/s. Age, BMI, SBP, DBP, FBS, TBARS and homocysteine levels were significantly higher in SLE patients with baPWV value 1400 cm/s than in SLE patients with baPWV value 1400 cm/s. In addition, baPWV correlated significantly with age, SBP, DBP, FBS and homocysteine. Moreover, stepwise multiple regression analysis showed that age and SBP were independently associated with baPWV. The results of this study indicate a possible link between vascular stiffness measured by baPWV and cardiovascular risk factors in patients with SLE.

Do Statins Lower Blood Pressure?

Hypercholesterolemia is present in many patients with hypertension and adds a significant component of cardiovascular risk. The 3-hydroxy-3 methyl-glutarylcoenzyme A reductase inhibitors (statins) lower low-density lipoprotein cholesterol but also inhibit many of the structural and functional components of the arteriosclerotic process. Structural effects include reductions in vascular smooth muscle hypertrophy and proliferation, fibrin deposition, and collagen cross-linking. Among the functional effects are improvements in endothelial function, reduction in inflammatory cytokines and reactive oxygen species, and down-regulation of angiotensin II and endothelin receptors. These would be expected to reduce blood pressure in patients with hypertension; 14 studies have shown statin-induced decrease in blood pressure, but 11 studies showed no effect. Many of the studies had no placebo controls, were of short duration, or had small sample sizes, or combinations of these. Despite predictions made on the basis of the vasoprotective actions of statins, the blood-pressure-lowering effects of statins are at best modest.

Effects of statin therapy on augmentation index as a measure of arterial stiffness: A systematic review and meta-analysis

OBJECTIVE

To evaluate the effects of statin therapy on augmentation index (AIx) as a measure of arterial stiffness using a meta-analysis of clinical trials.

METHODS

The search included PubMed-Medline, Embase, SCOPUS, Web of Science and Google Scholar databases to identify randomized controlled trials investigating the effects of statin therapy on arterial stiffness measured as AIx. A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. Random-effects meta-regression was performed using unrestricted maximum likelihood method to evaluate the impact of potential confounders.

RESULTS

18 trials examining the effects of statin therapy on arterial stiffness were included. A significant reduction in aortic AIx following statin therapy was proven (WMD: -2.40%, 95% CI: -4.59, -0.21, p=0.032; I(2): 51.20%). HR-adjusted AIx 75% values also revealed a significant improvement by statin therapy (WMD: -5.04%, 95% CI: -7.81, -2.27, p<0.001; I(2): 0%), but not when analysis was restricted to unadjusted AIx values (WMD: -2.30%, 95% CI: -4.83, 0.23, p=0.075; I(2): 53.83%). There was no significant change in carotid (WMD: -2.75%, 95% CI: -8.06, 2.56, p=0.309; I(2): 26.86%) and peripheral (WMD: 0.25%, 95% CI: -3.31, 3.82, p=0.889; I(2): 72.19%) AIx due to statin treatment. There was also no difference in the effect size calculated for different statins subgroups. The impact of statins on AIx was independent of LDL-cholesterol level (slope: 0.05; 95% CI: -0.02, 0.13; p=0.181).

CONCLUSION

Statin therapy causes a significant reduction in aortic AIx which is independent of LDL-cholesterol changes.

"Inflammation and arterial stiffness in humans"

Arterial stiffness is an established marker of cardiovascular morbidity and mortality and a potential therapeutic target. While hypertension and aging are established factors contributing to arterial stiffness, the role of inflammation in stiffening of the arteries is less well understood. We summarize existing literature regarding inflammation and arterial stiffness, including a discussion of the potential mechanisms by which inflammation may lead to arterial stiffening and studies assessing: (1) The association between subclinical inflammation and arterial stiffness in the general population; (2) The presence of increased arterial stiffness in primary inflammatory diseases; (3) The effect of anti-inflammatory therapy on arterial stiffness in primary inflammatory disease including the effect of statins; (4) Experimental evidence of immunization-induced arterial stiffening in normal adults. We discuss potential opportunities to assess the impact of anti-inflammatory interventions on arterial stiffness in subjects without primary inflammatory conditions. We also review the effect of inflammation on wave reflections.

Reference value of brachial-ankle pulse wave velocity for the eastern Chinese population and potential influencing factors

The present study was conducted to obtain reference values for brachial-ankle pulse wave velocity (baPWV) and to evaluate influencing factors of baPWV according to gender. Using automatic devices, baPWV was measured simultaneously in 2095 subjects. A total of 647 healthy subjects, none of whom presented atherosclerotic risk factors, were analyzed in the present study. Two different statistical methods were used to obtain reference values for baPWV according to subject gender and age. The association between baPWV value and gender, as well as other features, were analyzed. For male subjects, multiple stepwise analysis showed that age, systolic blood pressure (SBP), heart rate (HR), and plasma levels of triglycerides (TG) were independent predictors of baPWV. For female subjects, age, SBP, HR, and plasma levels of uric acid (UA) were independent predictors of baPWV. In male subjects, the upper limits of baPWV values were 1497.43/1425.00, 1518.67/1513.25, 1715.97/1726.50, 1925.20/1971.90, and 2310.18/2115.00 cm/s, obtained using two different statistical methods for the age ranges of 30-39, 40-49, 50-59, 60-69, and 70 and older, respectively. For females, the upper limits of baPWV values were 1426.70/1411.13, 1559.15/1498.95, 1733.50/1739.00, 1958.63/1973.78, and 2720.80/2577.00 cm/s for the age ranges of 30-39, 40-49, 50-59, 60-69, and 70 and older, respectively. Aging is the most important influencing factor for baPWV value and its effect is more prominent in females. The reference values of baPWV according to age and gender may be useful for the clinical diagnosis and preventive therapy of cardiovascular diseases.

Dextromethorphan, chlorphenamine and serotonin toxicity: case report and systematic literature review

The aim of this review was to describe a patient with serotonin toxicity after an overdose of dextromethorphan and chlorphenamine and to perform a systematic literature review exploring whether dextromethorphan and chlorphenamine may be equally contributory in the development of serotonin toxicity in overdose. A Medline literature review was undertaken to identify cases of serotonin toxicity due to dextromethorphan and/or chlorphenamine. Case reports were included if they included information on the ingested dose or plasma concentrations of dextromethorphan and/or chlorphenamine, information about co-ingestions and detailed clinical information to evaluate for serotonin toxicity. Cases were reviewed by two toxicologists and serotonin toxicity, defined by the Hunter criteria, was diagnosed when appropriate. The literature was then reviewed to evaluate whether chlorphenamine may be a serotonergic agent. One hundred and fifty-five articles of dextromethorphan or chlorphenamine poisoning were identified. There were 23 case reports of dextromethorphan, of which 18 were excluded for lack of serotonin toxicity. No cases were identified in which serotonin toxicity could be solely attributed to chlorphenamine. This left six cases of dextrometorphane and/or chlorphenamine overdose, including our own, in which serotonin toxicity could be diagnosed based on the presented clinical information. In three of the six eligible cases dextromethorphan and chlorphenamine were the only overdosed drugs. There is substantial evidence from the literature that chlorphenamine is a similarly potent serotonin re-uptake inhibitor when compared with dextrometorphan. Chlorphenamine is a serotonergic medication and combinations of chlorphenamine and dextromethorphan may be dangerous in overdose due to an increased risk of serotonin toxicity.

Current role of statins in the treatment of essential hypertension

IMPORTANCE OF THE FIELD

Hypertension and hyperlipidemia often co-exist and seem to be interrelated through common pathophysiological pathways. Drugs employing beneficial effects in both conditions could be advantageous in a concerted effective management of patients at high cardiovascular risk. Statins are known to enhance cardiovascular protection beyond their lipid-lowering capacity.

AREAS COVERED IN THIS REVIEW

MEDLINE was searched, up to January 2010, for studies assessing the effect of statin treatment on blood pressure control in various populations or animal models of hypertension. The potential mechanisms implicated in the putative antihypertensive action of statins are also reviewed.

WHAT THE READER WILL GAIN

To learn about the role of statins as potential antihypertensive drugs in various populations. Clinical advice for the use of statins either as monotherapy or in combination with antihypertensive drugs in high-risk populations is also provided.

TAKE HOME MESSAGE

Statins may exert a mild, but clinically relevant, antihypertensive effect which is probably mediated by mechanisms that are independent of their lipid-lowering effects. Patients with high BP levels at baseline as well as those treated with ACE inhibitors and calcium channel blockers are expected to benefit more in this regard.

Dissociation of aortic pulse wave velocity with risk factors for cardiovascular disease other than hypertension: a systematic review

Carotid-femoral pulse wave velocity (cfPWV), a measure of large artery stiffness, is an important predictor of cardiovascular events. This has been attributed to it being an integrative measure of the impact of cardiovascular risk factors on the arterial wall. Pulse wave velocity is strongly associated with age and blood pressure. However, findings with regard to its relation with other risk factors have been inconsistent. We performed a systematic review of cross-sectional published literature reporting independent associations of cfPWV in multivariable regression models. Articles were selected from a PubMed search using a prespecified search strategy. Studies were included if they did the following: (1) measured cfPWV; (2) reported on associations with cfPWV from regression models; and (3) considered age and blood pressure in the model. From 637 retrieved articles, 65 met our inclusion criteria, and 12 studies were included from reference searches. Age and blood pressure were consistently independently associated with cfPWV (91% and 90% of studies, respectively). Diabetes mellitus was associated with cfPWV in 52% studies, but the strength of the association was low. The majority of studies found no independent association between cfPWV and sex, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, smoking, or body mass index. The contribution of risk factors other than age and blood pressure to cfPWV is, thus, small or insignificant. The prognostic value of cfPWV may relate to a process of arterial ageing unrelated to classic risk factors other than hypertension.

Gender-specific regulation of pancreatic islet blood flow, insulin levels and glycaemia in spontaneously diabetic Goto-Kakizaki rats

Patients with diabetes are often treated with a statin for hyperlipidaemia and an ACE (angiotensin-converting enzyme) inhibitor or angiotensin receptor antagonist for hypertension or albuminuria. These drugs may also exert beneficial metabolic effects, causing improved glucose tolerance in patients. Gender-related differences have also been observed in the clinical responsiveness to these drugs, but the mechanism behind this is unclear. In the present study, we have investigated whether these drugs and the fatty acid palmitate influence the pancreatic microcirculation, thereby having an impact on insulin secretion and glycaemia in vivo, in spontaneously diabetic male and female Goto-Kakizaki rats. In male rats, pancreatic IBF (islet blood flow) and total PBF (pancreatic blood flow) were increased significantly by pravastatin, captopril and irbesartan. Serum insulin levels were increased by pravastatin and captopril. Palmitate suppressed pancreatic IBF and increased blood glucose. In female animals, pancreatic IBF was stimulated by captopril, candesartan and irbesartan. Total PBF was increased by captopril, candesartan and irbesartan, and by pravastatin. Palmitate suppressed pancreatic IBF and serum insulin secretion. In conclusion, the present study lends support to the view that a local pancreatic RAS (renin-angiotensin system) and pravastatin may be selectively influencing the pancreatic microcirculation and therefore affecting insulin secretion and glycaemia. NEFAs (non-esterified fatty acids) impaired pancreatic IBF, suppressed insulin secretion and increased blood glucose. Substantial gender-related differences in the vascular and metabolic responses to these drugs prevail in this animal model of diabetes.

Assessment of arterial stiffness, a translational medicine biomarker system for evaluation of vascular risk

AIMS

Stiffening of the large arteries is a common feature of aging and is exacerbated by a number of disorders such as hypertension, diabetes, and renal disease. Arterial stiffening is recognized as an important and independent risk factor for cardiovascular events. This article will provide a comprehensive review of the recent advance on assessment of arterial stiffness as a translational medicine biomarker for cardiovascular risk.

DISCUSSIONS

The key topics related to the mechanisms of arterial stiffness, the methodologies commonly used to measure arterial stiffness, and the potential therapeutic strategies are discussed. A number of factors are associated with arterial stiffness and may even contribute to it, including endothelial dysfunction, altered vascular smooth muscle cell (SMC) function, vascular inflammation, and genetic determinants, which overlap in a large degree with atherosclerosis. Arterial stiffness is represented by biomarkers that can be measured noninvasively in large populations. The most commonly used methodologies include pulse wave velocity (PWV), relating change in vessel diameter (or area) to distending pressure, arterial pulse waveform analysis, and ambulatory arterial stiffness index (AASI). The advantages and limitations of these key methodologies for monitoring arterial stiffness are reviewed in this article. In addition, the potential utility of arterial stiffness as a translational medicine surrogate biomarker for evaluation of new potentially vascular protective drugs is evaluated.

CONCLUSIONS

Assessment of arterial stiffness is a sensitive and useful biomarker of cardiovascular risk because of its underlying pathophysiological mechanisms. PWV is an emerging biomarker useful for reflecting risk stratification of patients and for assessing pharmacodynamic effects and efficacy in clinical studies.

Investigation of the vascular and pleiotropic effects of atorvastatin and pioglitazone in a population at high cardiovascular risk

We investigated the effect of atorvastatin monotherapy and combined treatment with atorvastatin and pioglitazone on intima-media thickness, vascular function and the cardiovascular risk profile. In all, 148 patients (76 male, 72 female; aged 61.4+/-6.5 years; body mass index [BMI] 29.2+/-4.1 kg/m2; mean +/- SD) with increased cardiovascular (CV) risk factors were randomised. Intima-media thickness (IMT), the augmentation index (Aix@75), the microvascular response to acetylcholine (LDF), lipid status, and plasma levels of intact proinsulin, adiponectin, interleukin-6 (IL-6), monocyte chemotactic protein-1 (MCP-1), matrix metalloproteinase-9 (MMP-9), sCD40L, P-selectin, tissue plasminogen activator (t-PA) and blood lipids were monitored over six months. Atorvastatin treatment, alone and in combination with pioglitazone, revealed a significant regression in IMT (0.923+/-0.013 to 0.874+/-0.012 mm and 0.921+/-0.015 to 0.882+/-0.015 mm; mean +/- SEM; p<0.05 respectively) and Aix@75 (27.3+/-1.2 to 25.9+/-1.4; and 25.6+/-1.4 to 24.8+/-1.7%; p<0.05). The endothelial response to acetylcholine as measured by laser Doppler fluximetry (LDF) improved during combined treatment (373+/-57 to 576+/-153 AU; p<0.05). Addition of pioglitazone to atorva-statin resulted in significant further effects on high-sensitivity C-reactive protein (hsCRP), t-PA, P-selectin, adiponectin, triglycerides and high-density lipoprotein (HDL) cholesterol (p<0.05 respectively). Atorvastatin significantly improved IMT and vascular elasticity. Co-administration of pioglitazone provided additional effects on endothelial function, lipid profile and laboratory markers of inflammation.

Fluvastatin decreases cardiac fibrosis possibly through regulation of TGF-beta(1)/Smad 7 expression in the spontaneously hypertensive rats

Statins ameliorate myocardial fibrosis after myocardial infarction. We designed this study to determine whether fluvastatin reduced hypertension-induced myocardial hypertrophy and fibrosis and whether these fluvastatin effects involved transforming growth factor beta1 (TGF-beta1) and Smad 7, factors known to play a role in the myocardial hypertrophy and fibrosis. We randomized 14 week old spontaneously hypertensive rats (SHRs) to receiving vehicle or 5-20 mg/kg/day fluvastatin for 8 weeks. Wistar Kyoto (WKY) rats receiving vehicle or 10 mg/kg/day fluvastatin were also studied. SHRs had an increased blood pressure, left ventricular hypertrophy and fibrosis compared with WKY rats. SHRs also had an elevated TGF-beta1 expression and a decreased Smad 7 expression. These changes in SHRs were dose-dependently attenuated by fluvastatin. For example, the hydroxyproline content was 3.2+/-0.1, 4.0+/-0.1 and 3.5+/-0.1 microg/mg heart and the Smad 7 protein expression was 5.1+/-0.6, 1.0+/-0.1 and 4.1+/-0.7 arbitrary units for WKY rats, SHRs and SHRs receiving 20 mg/kg/day fluvastatin, respectively. The hydroxyproline content in the SHRs treated with or without fluvastatin was positively correlated with the left ventricular mass index, systolic blood pressure and the amount of TGF-beta1 proteins and negatively correlated with the Smad 7 expression level. The left ventricular mass index was positively correlated with the systolic blood pressure. Fluvastatin did not alter the blood pressure, left ventricular mass index and collagen content of WKY rats. These results suggest that fluvastatin reduces hypertension-induced myocardial hypertrophy and fibrosis. These effects may involve an increased expression of Smad 7 and a decreased expression of TFG-beta1. Our results call for clinical studies to evaluate these fluvastatin effects in hypertensive patients.

Endothelial function, arterial stiffness and lipid lowering drugs

The endothelium is a dynamic organ that plays a pivotal role in cardiovascular homeostasis. Alteration in endothelial function precedes the development of atherosclerosis and contributes to its initiation, perpetuation and clinical manifestations. It has been suggested that the assessment of endothelial function could represent a barometer of vascular health that could be used to gauge cardiovascular risk. This review summarises the various methods used to assess endothelium-dependent vasodilatation and their potential prognostic implications. In addition, the techniques used to evaluate arterial stiffness are discussed. The latter is to some extent controlled by the endothelium and has been the subject of considerable research in recent years. This paper also discusses the effects of lipid lowering treatment on both endothelial function and arterial stiffness.

Vasoactive drugs enhance pancreatic islet blood flow, augment insulin secretion and improve glucose tolerance in female rats

Pravastatin, irbesartan and captopril are frequently used in the treatment of patients with Type 2 diabetes. These drugs also exert beneficial metabolic effects, causing an improved glucose tolerance in patients, but the precise mechanisms by which this is achieved remain elusive. To this end, we have studied whether these drugs influence insulin secretion in vivo through effects on islet blood perfusion. Captopril (3 mg/kg of body weight), irbesartan (3 mg/kg of body weight) and pravastatin (0.5 mg/kg of body weight) were injected intravenously into anaesthetized female Wistar rats. Blood flow rates were determined by a microsphere technique. Blood glucose concentrations were measured with test reagent strips and serum insulin concentrations were measured by ELISA. Pancreatic blood flow was markedly increased by pravastatin (P<0.001), captopril (P<0.05) and irbesartan (P<0.01). Pancreatic islet blood flow was significantly and preferentially enhanced after the administration of captopril (P<0.01), irbesartan (P<0.01) and pravastatin (P<0.001). Kidney blood flow was enhanced significantly by pravastatin (P<0.01), irbesartan (P<0.05) and captopril (P<0.01). Captopril and pravastatin also enhanced late-phase insulin secretion and positively influenced glycaemia in intraperitoneal glucose tolerance tests. In conclusion, the present study suggests that a local pancreatic renin-angiotensin system and pravastatin treatment may be selectively controlling pancreatic islet blood flow, augmenting insulin secretion and thereby improving glucose tolerance. Our findings indicate significant gender-related differences in the vascular response to these agents. Since statins and renin-angiotensin system inhibitors are frequently used by diabetic patients, the antidiabetic actions of these drugs reported previously might occur, in part, through the beneficial direct islet effects shown in the present study.

Recovery from vecuronium is delayed in patients with hypercholesterolemia

PURPOSE

To examine the effects of hypercholesterolemia with respect to onset time and recovery from vecuronium-induced neuromuscular block.

METHODS

A randomized controlled trial was undertaken in 20 adult patients with hypercholesterolemia (hypercholesterolemia group) and 20 healthy patients with normal serum cholesterolemia (control group). Following induction of anesthesia, vecuronium 0.1 mg.kg(-1) iv was administered. Onset of neuromuscular block and recovery times in the two groups were compared using supramaximal stimulation of the ulnar nerve.

RESULTS

The supramaximal stimulating current in the hypercholesterolemia group was similar to that of the control group (38.1 +/- 15.5 vs 31.3 +/- 7.6 mA, P = 0.087). Onset of vecuronium-induced neuromuscular block (time to loss of response to T1) in the hypercholesterolemia group was similar to that observed in the control group (243 +/- 84 vs 249 +/- 56 sec, P = 0.792). Times from vecuronium administration to the return of T1 were also similar in the two groups (29.8 +/- 9.7 vs 25.3 +/- 6.8 min, P = 0.099). However, mean times for return of T2, T3, and T4 in the hypercholesterolemia group were longer than in the control group (44.5 +/- 14.4 vs 34.0 +/- 8.4 min for T2, P = 0.018). During recovery from neuromuscular block, T1/control and train-of-four ratio in the hypercholesterolemia group were less than in the control group, 90-120 min and 70-120 min after vecuronium, respectively (P < 0.05).

CONCLUSION

Recovery from vecuronium-induced neuromuscular block is delayed in patients with hypercholesterolemia.

Pancreatic islet blood flow is selectively enhanced by captopril, irbesartan and pravastatin, and suppressed by palmitate

Diabetic patients are often treated with a lipid lowering statin and an ACE inhibitor or angiotensin receptor antagonist against hypertension or albuminuria. These drugs may also improve glucose tolerance, but the mechanism for this remains elusive. We now studied whether these drugs and the fatty acid palmitate influence insulin secretion in vivo in rats through effects on islet blood perfusion. Whole pancreatic blood flow was markedly increased by captopril and irbesartan, and decreased by palmitate. Islet blood flow was significantly and preferentially enhanced by captopril, irbesartan, and pravastatin, and suppressed by palmitate. Both captopril and irbesartan raised serum insulin concentrations significantly. However, glycemia was not affected in any group. In conclusion, the present study suggests that a local pancreatic RAS and pravastatin may be selectively controlling pancreatic islet blood flow and thereby influencing insulin secretion. The antidiabetic actions of statins and RAS inhibitors might in part occur through the beneficial direct islet effects shown here. Conversely, free fatty acids that are elevated in type 2 diabetic patients may contribute to an impaired nutritive islet blood flow and thereby further aggravate the diabetic state by limiting the supply of insulin needed to curb hyperglycemia.

The effects of lipid-lowering drug therapy on cardiovascular responsiveness in type 2 diabetic patients

Type 2 diabetes is associated with a high prevalence of dyslipidaemia and a high incidence of cardiovascular disease. Lipid lowering therapy with HMG Co-A reductase inhibitors (statins) reduce the risk of cardiovascular events in type 2 diabetic and non-diabetic patients, effects which are believed to be partly due to improvements in vascular function. The aetiology of abnormal vascular function in type 2 diabetics is likely to be multifactorial and the pattern of vascular dysfunction in type 2 diabetes may differ from that which occurs in non-diabetic patients with dyslipidaemia. Abnormalities in endothelium derived hyperpolarising factor (EDHF) mediated vasodilation in resistance vessels may be more prominent in both type 1 and type 2 diabetes than in non-diabetic patients with endothelial dysfunction. The effects of lipid lowering therapy on vascular responsiveness may differ in type 2 diabetic patients from those found in non-diabetic patients. Statin therapy does not appear to improve responses to endothelial dependent vasodilators in type 2 diabetics, but may alter the ratio between nitric oxide (NO) and EDHF mediated responses. Fibrate therapy improves flow mediated dilation of brachial arteries in type 2 diabetic patients, but only appears to improve endothelium dependant vasodilator responses in resistance vessels when given in conjunction with co-enzyme Q.

The Anti-Atherosclerotic Effects of Lipid Lowering with Atorvastatin in Patients with Hypercholesterolemia

We investigated the lipid lowering and anti-atherosclerotic effects of atorvastatin in patients with hypercholesterolemia. Thirty patients were given atorvastatin 10 mg daily, and assessed for serum lipids, intima-media thickness (IMT), and brachial-ankle pulse wave velocity (ba-PWV) at the baseline, 6 months, and 12 months. Remnant-like particle-cholesterol (RLP-C), lipoprotein (a)(Lp(a)), and high-sensitivity C-reactive protein (hs-CRP) were measured in some patients at the baseline and at 6 months. Total cholesterol, triglyceride and low-density lipoprotein cholesterol were significantly decreased by 32%, 23% and 44% at 6 months, respectively, and these effects were sustained at 12 months. There was no change in high-density lipoprotein cholesterol. IMT at the baseline was 0.88 +/- 0.16 mm and decreased to 0.76 +/- 0.13 mm at 6 months, remaining at 0.75 +/- 0.12 mm at 12 months. We did not observe any significant changes in ba-PWV. RLP-C and hs-CRP were significantly reduced from 7.3 +/- 10.8 mg/dL to 4.3 +/- 5.3 mg/dL and 0.075 +/- 0.065 mg/dL to 0.039 +/- 0.043 mg/dL at 6 months, respectively. There was no change in Lp(a). The observed decrease in IMT suggests that atorvastatin possibly improves atherosclerosis, in addition to the significant reduction of serum lipids.

Pravastatin Decreases Blood Pressure in Hypertensive and Hypercholesterolemic Patients Receiving Antihypertensive Treatment

BACKGROUND

Previous studies have suggested that the lipid-lowering agents, statins, may help reduce blood pressure (BP). The goal of the present study was to characterize the effect of pravastatin on BP in hypercholesterolemic and hypertensive patients already receiving antihypertensive drugs.

METHODS AND RESULTS

Eighty-two patients with hypercholesterolemia were retrospectively studied before and after 3 months of treatment with pravastatin. Forty-four patients had hypertension (HT group) and were receiving antihypertensive treatment, while the remaining 38 patients were normotensive (NT group). Patients in the HT group were further subdivided into those with uncontrolled or controlled BP. Pravastatin treatment significantly reduced systolic BP (SBP) in the HT group (134+/-16 to 130+/-13 mmHg, p<0.005) but not in the NT group (124+/-10 to 123+/-9 mmHg, p=0.52), despite the fact that treatment significantly reduced low-density lipoprotein cholesterol in both groups (HT group 178+/-27 to 132+/-17 mg/dl, p<0.0001; NT group 169+/-27 to 125+/-21 mg/dl, p<0.0001). Further, pravastatin significantly decreased SBP in the uncontrolled BP group (148+/-7 to 138+/-12 mmHg, p<0.005) but not in the controlled BP group (122+/-10 to 123+/-9 mmHg, p=0.72).

CONCLUSION

Concomitant use of statins and antihypertensive drugs could result in improved BP control in hypertensive patients with hypercholesterolemia.

Lowering of Elevated Ambulatory Blood Pressure by HMG-CoA Reductase Inhibitors

Controversial results were reported as to a possible blood pressure-lowering effect of statins. This may relate to methodological limitations (blood pressure measuring techniques) or to putative different effects of statins in different biologic conditions (cholesterol or blood pressure levels, age, etc). Patients with cholesterol>200 mg/dL and no previous statin treatment underwent 24-hour ambulatory blood pressure (ABP) monitoring and were classified as normotensives or hypertensives according to their ABP. They were randomized to statin (n=51, simvastatin or pravastatin, 10-20 mg/d; atorvastatin, 5-10 mg/d) or control treatment (n=23, soy lecithin, 20 g/d) for 2 months, after which ABP assessment was repeated. No consistent treatment-related reduction in ABP was observed in lecithin-treated patients (either hypertensives or normotensives) or in statin-treated normotensive patients (-0.7+/-5.1/-1.0+/-4.6 mm Hg, both P=ns). In contrast, statin-treated hypertensive patients showed lower systolic and diastolic blood pressure (-5.7+/-5.8/-3.5+/-3.9 mm Hg, both P<0.001), the effect was entirely accounted for by reduced daytime values with no change in nighttime values, and it was unrelated to the concomitant statin-induced cholesterol reduction. Statins moderately but significantly lower blood pressure in patients with high (but not with normal) ABP; the effect is confined to the daytime period and is unrelated to the extent of the cholesterol lowering.

Add-on and withdrawal effect of pravastatin on proteinuria in hypertensive patients treated with AT1 receptor blockers

BACKGROUND

Although angiotensin receptor antagonists and 3-hydroxy-3-methylgultaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) have been shown to attenuate proteinuria individually, it remains unclear whether proteinuria may be additionally improved by statin therapy in well-controlled hypertensive patients treated with angiotensin receptor antagonists-based regimen and whether withdrawal of chronic statin treatment may abrogate this beneficial effect in normolipidemic patients.

METHODS

A total of consecutive 82 proteinuric patients treated with antihypertensive agents, including losartan, were randomized 10 mg of pravastatin or placebo with a 6-month treatment. After completing 6 months of drug treatment, the pravastatin-treated patients were randomly assigned to continue (N= 19) or withdraw (N= 17) pravastatin for a further 6 months.

RESULTS

Subjects treated with pravastatin had significant further improvement of proteinuria at 6 months compared with placebo group (559 +/- 251 mg/24 hours vs. 1262 +/- 557 mg/24 hours) (P < 0.0001). Of 17 patients assigned to withdraw pravastatin, proteinuria returned to the pretreatment levels and was significantly higher than those who continued treatment. Multivariate analysis revealed that proteinuric improvement was significantly correlated with the continuous statin use. Urinary excretion of endothelin-1 (ET-1) is decreased in pravastatin-treated patients, but withdrawal of statin resulted in 27% up-regulation. The linear regression models in the initial statin-treated group showed that changes in urinary ET-1 correlated with urinary protein excretion (r= 0.83, P < 0.0001).

CONCLUSION

We conclude that pravastatin administration is associated with improved proteinuria probably by inhibiting urine ET-1 levels in patients with losartan-based treatment. However, statin withdrawal abrogates this beneficial effect in patients initially responsive to this therapy.

Effect of pravastatin on left ventricular mass by activation of myocardial K ATP channels in hypercholesterolemic rabbits

Epidemiological studies showed that hypercholesterolemia was associated with a higher left ventricular mass. Myocardial ATP-sensitive potassium (K(ATP)) channels have been implicated in the development of cardiac hypertrophy. We investigated the effect of pravastatin on hypercholesterolemia-induced ventricular hypertrophy and whether the attenuated hypertrophic effect was via activation of myocardial K(ATP) channels. In this study, we evaluated the hemodynamic, biochemical, and morphological responses to pravastatin in cholesterol-fed (1%) rabbits. Male New Zealand White rabbits were randomized to either vehicle, nicorandil (an agonist of K(ATP) channels), pravastatin, glibenclamide (an antagonist of K(ATP) channels), or a combination of nicorandil and glibenclamide or pravastatin and glibenclamide for 8 weeks. The left ventricular weight and left ventricular myocyte sizes increased 8 weeks after cholesterol-feeding in comparison to that in normocholesterolemic rabbits. Pravastatin administration significantly decreased the left ventricular weight by 12% and cardiomyocyte cell areas by 30%. Hyperlipidemic rabbits in the nicorandil- and pravastatin-treated groups significantly attenuated cardiomyocyte hypertrophy, as compared with the vehicle-treated group (3162 +/- 277 microm(2), 3372 +/- 228 microm(2) versus 4388 +/- 163 microm(2) in the vehicle group, both P < 0.0001, respectively). Nicorandil-induced effects were abolished by administering glibenclamide. Similarly, pravastatin-induced beneficial effects were reversed by the addition of glibenclamide, implicating K(ATP) channels as the relevant target. The results of the present study suggest a pathogenetic role of K(ATP) channels in hypercholesterolemia-induced ventricular hypertrophy. The antihypertropic effects of pravastatin may be related to activation of K(ATP) channels, and result in an amelioration of cardiomyocyte hypertrophy development by an atherogenic diet.

Statins and newly diagnosed diabetes

AIMS

In order to evaluate a hypothesized protective effect of the use of HMG Co-A reductase inhibitors (statins) on the development of Type 2 diabetes, we conducted a nested case-control study based on data from the UK-based General Practice Research Database (GPRD).

METHODS

We identified a population of adults 30-79 years of age between 1 January 1991 and 31 March 2002, who were being treated with a statin or who were diagnosed with hyperlipidaemia but were not being treated with a lipid-lowering drug. From this population we identified all incident cases of Type 2 diabetes. We conducted a nested case-control study encompassing 588 cases and 2063 matched controls.

FINDINGS

We observed an adjusted odds ratio (OR) of 1.1 [95% confidence interval (CI) 0.8, 1.4] for current statin users compared with non-exposed subjects and adjusted ORs for pravastatin use alone and simvastatin use alone compared with non-exposed of 0.7 (95% CI 0.4, 1.2) and 1.0 (95% CI 0.7, 1.3), respectively. There was little evidence for a duration effect for simvastatin in these data, though there is a slight suggestion of a long-term protective effect with pravastatin.

CONCLUSION

The current study results are most consistent with the conclusion that there is little if any protective effect of statins on the development of Type 2 diabetes.

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.

Association between different lipid-lowering treatment strategies and blood pressure control in the Brisighella Heart Study

BACKGROUND

Small studies have suggested that lipid-lowering strategies, and particularly statins, could influence blood pressure (BP) control. The aim of the present study was to evaluate the effect of different lipid-lowering strategies on BP control of subjects with hypercholesterolemia who were enrolled in the prospective, population-based, longitudinal Brisighella Heart Study.

METHODS

A total of 1356 subjects with total cholesterol levels >or=239 mg/dL were randomly treated for 5 years (1988-1993) with 1 of these lipid-lowering regimens: low-fat diet, cholestyramine, gemfibrozil, or simvastatin. Participants were divided at baseline into 4 quartiles according to systolic BP level and examined for the percent change in systolic and diastolic BP during the 5 years of treatment.

RESULTS

A significant decrease in BP was observed in the 2 upper quartiles of systolic BP (>or=140 mm Hg) and was greater in subjects treated with cholesterol-lowering drugs who also had a greater reduction in plasma levels of low-density lipoprotein cholesterol. The BP decrease was greater in patients treated with statin drugs and, among those treated with antihypertensive drugs, in subjects in the fourth quartile.

CONCLUSION

The use of lipid-lowering measures could significantly improve BP control in subjects with both hypercholesterolemia and hypertension. The reduction in BP seems to be enhanced in subjects treated with statins.

Effects of simvastatin on blood pressure in hypercholesterolemic patients: An open-label study in patients with hypertension or normotension

BACKGROUND

Simvastatin has been reported to improve endotheliumdependent vascular relaxation in patients with hypercholesterolemia. The consequent decrease in arterial stiffness might be associated with a decrease in blood pressure (BP).

OBJECTIVE

The aim of this study was to determine whether simvastatin 20 and 40 mg/d have an effect on systolic and diastolic blood pressure (SBP and DBP, respectively) in patients with hypercholesterolemia, and, if so, whether the effect is dose dependent and/or is related to the changes in the serum lipid profile.

METHODS

This 6-month, open-label study was conducted at the Lipid Clinics of the Department of Internal Medicine, University of Milan, Maggiore Hospital IRCCS, and of the Department of Internal Medicine 1, G. Salvini Hospital, Garbagnate Milanese (Milan, Italy). Patients aged 18 to 80 years with primary hypercholesterolemia who were following a low-fat, low-cholesterol diet for >2 months before the study were enrolled. Patients at high risk for cardiovascular disease (CVD), according to the National Cholesterol Education Program Adult Treatment Panel II guidelines, were given simvastatin 20 mg (tablet) QD for 3 months, and those at low risk for CVD continued with diet only for 3 months (controls). Efficacy variables included body weight, SBP, DBP, and serum lipid levels (total cholesterol [TC], low-density lipoprotein cholesterol [LDL-C], high density lipoprotein cholesterol [HDL-C], and triglycerides [TG]). At 3 months, patients in the simvastatin + diet group who reached their therapeutic goal continued to receive simvastatin 20 mg/d for 3 additional months. In simvastatintreated patients who were normotensive at baseline or who became normotensive at 3 months but who did not reach the therapeutic goal, the simvastatin dosage was increased to 40 mg/d. Patients in both groups who remained hypertensive at 3 months were switched to hypotensive therapy. In the diet-only group, patients who were formerly normotensive or who became normotensive at 3 months but who did not reach their therapeutic goal continued with diet only or started lipid-lowering therapy. All other patients in the diet-only group continued to be treated with diet only, for 3 additional months. Efficacy variables were measured again at 6 months. Tolerability of simvastatin was assessed at each visit using patient interview and measurement of serum aminotransferase and creatine phosphokinase levels.

RESULTS

The study population comprised 222 patients (132 women, 90 men; mean [SEM] age, 53.9 [0.95] years [range, 23-76 years]); 115 high-risk patients (57 with untreated stage 1 hypertension) were assigned to the simvastatin + diet group, and 107 low-risk patients (29 with untreated stage 1 hypertension) were assigned to the diet-only group. In the simvastatin group, after 3 months of therapy, mean SBP was decreased by 3.9 (1.49) mm Hg (change, -2.9%), mean DBP decreased by 3.0 (0.87) mm Hg (change, -3.7%), mean TC decreased by 90.6 (3.98) mg/dL (change, -27.0%), mean LDL-C decreased by 88.9 (3.88) mg/dL (change, -35.6%), and mean TG decreased by 26.3 (7.34) mg/dL (change, -15.8%) (all, P < 0.001). Mean HDL-C increased by 3.6 (1.16) mg/dL (change, 6.9%; P < 0.001). The BP-lowering effect was found only in patients with hypertension at baseline (n = 57); in these patients, mean SBP decreased by 7.2 (2.44) mm Hg (change, -4.8%; P < 0.005 vs baseline) and DBP decreased by 4.8 (1.29) mm Hg (change, -5.6%; P < 0.001 vs baseline). Also in the simvastatin group, 26 patients (22.6%) achieved their target SBP/DBP. In patients with normotension at baseline (n = 58), neither SBP nor DBP was changed significantly (changes, -0.8 [1.65] and -1.4 [1.15] mm Hg, respectively [-0.6% and -1.8%, respectively]). The changes in serum lipid levels were similar between hypertensive and normotensive patients in the simvastatin group. Forty-one patients (18 hypertensive and 23 normotensive at baseline) were treated with simvastatin 40 mg/d plus diet between months 3 and 6. At 6 months, no further significant decrease was observed in mean BP. In contrast, the expected dose-dependent response was observed for TC and LDL-C levels. In the diet-only group, no significant changes occurred in BP or serum lipid levels. Changes in BP, TC, LDL-C, TG, and HDL-C were significantly greater in the simvastatin + diet group than in the diet-only group (all, P < 0.001). Body weight did not change significantly in either group.

CONCLUSIONS

In this group of patients with hypercholesterolemia, the starting dosage of simvastatin (20 mg/d) was associated with reductions in SBP and DBP within 3 months of treatment in patients with hypertension, and this effect was independent of the lipid-lowering properties of the drug. Although the decrease in BP was modest, it is likely clinically relevant. Further studies on this topic are advisable.

Statin therapy and angiogenesis

PURPOSE OF REVIEW

Clinical studies suggested that 3-hydroxyl-3-methylglutaryl coenzyme A reductase inhibitor (statin) therapy has an additional cardiovascular protective activity that may function independently of the ability of statins to lower serum cholesterol. This paper reviews the available data on these effects and discusses the potential intracellular mechanisms involved.

RECENT FINDINGS

Experimental studies have clearly shown that statins protect against ischaemia-reperfusion injury of the heart, and exert pro-angiogenic effects by stimulating the growth of new blood vessels in ischaemic limbs of normocholesterolemic animals. The mechanisms underlying these serum lipid-independent statin effects are not completely understood, but there is increasing evidence that statins improve endothelial function through molecular mechanisms that mediate an increase in endothelium-derived nitric oxide. Recent research has revealed a link between statins and the serine/threonine protein kinase Akt that regulates multiple angiogenic processes in endothelial cells. In contrast to these data, it has also been reported that higher doses of statins can inhibit endothelial cell migration and angiogenesis.

SUMMARY

Statins have biphasic potential either to promote or inhibit angiogenesis. Low statin doses induce a pro-angiogenic effect through Akt activation and increase nitric oxide production, whereas high statin doses may decrease protein prenylation and inhibit cell growth. Notwithstanding, the clinical relevance of these serum lipid-independent effects is not fully understood. Further studies on the actions of statins on endothelial cells may lead to the identification of new pharmacological targets for the control of angiogenesis.

Low-dose atorvastatin therapy does not augment endothelial function in active hypercholesterolaemic males

AIMS

As statin therapy has been demonstrated to augment endothelial function in sedentary hypercholesterolaemia (HC), we aimed to investigate the effects of atorvastatin therapy on endothelial function in physically active, HC men.

METHOD AND RESULTS

Eleven physically active, HC males were recruited. Endothelial function [forearm blood flow response to brachial artery infusion of acetylcholine (Ach)] was assessed twice in each subject following atorvastatin or no therapy in a randomized crossover design. In addition, endothelial function was compared with an active, normolipidaemic control group (C). Atorvastatin therapy reduced total and LDL cholesterol, but had no effect on basal blood flow or endothelial function (peak ACh mean difference +/- standard error 0.75 +/- 1.75 ml min(-1) per 100 ml tissue) [95% confidence interval (CI) -3.1, 4.6]. In addition, there was no difference in endothelial function between the HC and C groups (-1.14 +/- 2.60 ml min(-1) per 100 ml tissue; CI -6.53, 4.25).

CONCLUSION

Statin therapy in HC patients with normal endothelial function does not augment endothelial function.

Influences of age and gender on results of noninvasive brachial-ankle pulse wave velocity measurement--a survey of 12517 subjects

The present study was conducted to evaluate the influences of age and gender on the results of noninvasive brachial-ankle pulse wave velocity (baPWV). In 12517 subjects who had no medication and no history of cardiovascular diseases, multiple regression analysis demonstrated that age, blood pressure, body mass index, triglycerides, blood glucose, and uric acid were significant variables for baPWV in both genders. From this population, we extracted 7881 "healthy subjects" (4488 males and 3393 females, 25-87 years) without any of the atherogenic risk factors, and the results of baPWV were analyzed chronologically in 5-year age intervals. baPWV was lower in females than in males until age 60, and became similar in both genders over age 60. Multiple regression analysis demonstrated that not only the value of R(2) but also the coefficient of the effect of age on baPWV are larger in females than in males. In the estimation of the regression curve, the relationship between age and baPWV demonstrated a quadratic curve in both genders. Thus, aging influences baPWV, and its effect is more prominent in female. Menopause seems to be the crucial phenomenon to explain the augmented increase in arterial stiffness with aging in females.

Usefulness of brachial-ankle pulse wave velocity measurement: correlation with abdominal aortic calcification

At present, brachial-ankle pulse wave velocity (baPWV) can be measured easily and noninvasively. We studied the correlation between aortic damage estimated by baPWV and that determined by measuring the length of abdominal aortic calcification (AAC) on X-ray films, which parameter has been significantly associated with cardiovascular morbidity and mortality. baPWV was measured using the form PWV/ankle brachial index (ABI) device in 97 patients free of end-stage renal failure or peripheral arterial disease. baPWV correlated significantly with age (r2=0.625, p<0.0001), was significantly higher in hypertensives than in normotensives (2,109+/-67 vs. 1,623+/-93 cm/s, p<0.0001), and correlated significantly with systolic blood pressure (r2=0.64, p<0.0001) and diastolic blood pressure (r2=0.397, p<0.0001). baPWV was significantly higher in diabetic patients than in nondiabetics (2,068+/-73 vs. 1,813+/-97 cm/s, p<0.05), but was similar in normolipidemic and hyperlipidemic patients. baPWV did not correlate with body mass index, fasting plasma glucose, total cholesterol, high density lipoprotein (HDL)-cholesterol, low density lipoprotein (LDL)-cholesterol or triglyceride levels, but correlated significantly with AAC length (r2=0.599, p<0.0001). Multiple regression analysis indicated that age, systolic blood pressure and AAC length were independent determinants of baPWV. Our results indicate that baPWV is useful for estimating aortic damage and could be a potentially useful predictor of vascular morbidity and mortality.

Association of pravastatin and left ventricular mass in hypercholesterolemic patients: role of 8-iso-prostaglandin f2alpha formation

Epidemiologic studies have shown that hypercholesterolemia is associated with increased left ventricular (LV) mass. Free radicals have been shown to be increased in hyperlipidemic patients. This study sought to determine whether pravastatin administration can affect LV mass in patients with untreated total cholesterol >or=240 mg/dl by reducing 8-iso-prostaglandin F concentrations, a reliable marker of oxidant injury. Fifty patients were randomly assigned to one of two groups, one with (n = 25) and one without (n = 25) treatment with pravastatin (10 or 20 mg/d). A group of normolipidemic control subjects was used for comparison. Echocardiograms were performed at baseline and after 6 months of therapy. Hyperlipidemic patients showed significant increases in LV mass index at baseline compared with the normolipidemic control group (125 +/- 8 vs. 107 +/- 5 g/m, p < 0.0001). Pravastatin treatment significantly reduced plasma total and low-density lipoprotein cholesterol levels, as well as increased high-density lipoprotein cholesterol. After 6 months of therapy with pravastatin, the magnitude of LV mass regression correlated with the magnitude of inhibition of free radical formation assessed by 8-iso-prostaglandin F formation (r = 0.67, p = 0.002). Multivariate analysis revealed that regression of LV mass was significantly correlated only with the changes in 8-iso-prostaglandin F (p < 0.0001, adjusted R = 0.83). These findings demonstrated for the first time that in addition to its primary anti-lipidemia, pravastatin may have an additional effect of reducing LV mass-independent lipid-lowering effects, possibly through attenuation of free radical formation.

Lipid lowering: another method of reducing blood pressure?

Modern management of cardiovascular risk depends on assessment of cardiovascular risk factors. Hypertension and hyperlipidaemia are synergistic risk factors for cardiovascular events. Both show a degree of cross-correlation through sharing mechanisms of pathogenesis including insulin resistance and endothelial dysfunction. This article reviews the common pathways leading to dyslipidaemia and hypertension and the effects diet and lipid-lowering drug therapies have had on correcting blood pressure in patients with essential hypertension. Both statins and fibrates have shown a capability to lower blood pressure by up to 8/5 and 15/10 mmHg respectively, in some small-scale clinical trials and have effects on arterial wall structure and hence pulse wave velocity. This blood pressure action may account for some of the clinical effects of lipid-lowering drugs on cardiovascular risk. Thus, lipid lowering may provide an additional method of correcting hypertension in some high-risk patients. However, data from large-scale intervention trials are either absent or ambiguous. Definitive large-scale trials to investigate the antihypertensive effects of lipid-lowering drugs are required, although end point studies examining the interaction of lipid-lowering and antihypertensive drugs to determine optimum combinations are already under way.

Arterial elastic properties and cardiovascular risk/event

Cardiovascular disease is a major cause of morbidity and mortality in the western world. There is convincing evidence that the elastic properties, particularly of large arteries, are impaired in the presence of cardiovascular disease and risk factors such as cigarette smoking, hypertension, diabetes and ageing. Evidence is also emerging that treatment of these risk factors is associated with an improvement in the elastic properties, mirrored by a reduction in the cardiovascular risk and events. The main problems associated with arterial elasticity are the multiple definitions and methods of measurement and the problem of obtaining reliable nearby blood pressure measurement. Nevertheless, duplex estimation appears to be a non-invasive, accurate and reliable method of defining these properties. This method is broadly used as a research tool, but there is a good case for its use in clinical practice, particularly in the screening of patients at risk of cardiovascular events.

Effects of atorvastatin on aortic pulse wave velocity in patients with hypertension and hypercholesterolaemia: a preliminary study

As statins may contribute to plaque stabilisation, it is important to evaluate whether these drugs may modify arterial stiffness. In 23 patients, aged 32-70 years, with hypertension and hypercholesterolaemia, a double-blind randomised study vs placebo was performed to evaluate whether atorvastatin was able to modify aortic stiffness, measured from aortic pulse wave velocity (PWV), after a 12-week treatment. The results revealed that atorvastatin did not change blood pressure, significantly lowered (P<0.003; <0.002) plasma total and LDL cholesterol, and increased aortic PWV by +8% (vs -2% under placebo) (P<or=0.05). The percentage changes in plasma total and LDL cholesterol and in PWV were significantly and negatively correlated, independent of blood pressure level. The finding of increased aortic PWV after 12-week statin treatment agrees with studies in monkeys, indicating that, at the early phase of hypolipidaemic diet but not later, aortic PWV increases transiently as a consequence of the significant reduction of lipid vascular content. In conclusion, the present results support the possibility that statins might contribute to a change in arterial stiffness independent of blood pressure level, and suggest that long-term studies in humans are needed to evaluate the contribution of arterial elasticity to statin-induced vascular remodelling.

Augmentation index as a measure of peripheral vascular disease state

Pulse pressure, especially in central arteries, is an independent predictor of adverse cardiovascular events in patients with increased elastic artery stiffness (or elastance). The central arterial pressure wave is composed of a forward traveling wave generated by left ventricular ejection and a later arriving reflected wave from the periphery. Increased stiffness of elastic arteries is the primary cause of increased pulse pressure in subjects with degeneration and hyperplasia of the arterial wall. As stiffness increases, transmission velocity of both forward and reflected waves increase, which causes the reflected wave to arrive earlier in the central aorta and augments pressure in late systole [ie, augmentation index = (augmented pressure/pulse pressure) increases]. These changes in wave reflection properties are associated with vascular disease and aging and cause an increase in left ventricular afterload, myocardial mass, and oxygen consumption. Vasoactive drugs have little direct effect on large elastic arteries but can markedly change wave reflection amplitude and augmentation index by altering stiffness of the muscular arteries and modifying transmission velocity of the reflected wave from the periphery to the heart. This change in amplitude and timing of the reflected wave causes a generalized change in central arterial systolic and pulse pressure that is not detected by cuff pressure measurements in the brachial artery.

Interactions between hypercholesterolemia and hypertension: implications for therapy

PURPOSE OF THE REVIEW

The purpose of the present review is to summarize the available information that supports the therapeutic role for the concomitant and aggressive management of hypercholesterolemia and hypertension.

RECENT FINDINGS

A concomitant management of hypertension and high-plasma cholesterol has been suggested to significantly reduce the extent of cardiovascular complications. Hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) have been demonstrated to be very effective in the treatment of patients with hypercholesterolemia where they reduce the rate of coronary and cerebrovascular complications. This benefit is largely extended to the hypertensive population. Very recently some studies have demonstrated the capacity of statins to improve blood pressure control in patients with hypertension and this effect, which has not been demonstrated for the other lipid-lowering drugs, could be very important in the clinical management of overall cardiovascular risk.

SUMMARY

These findings confirm that the prevention of cardiovascular diseases should be based on the aggressive treatment of many different risk factors. This is particularly true for patients with hypertension and hypercholesterolemia for whom the negative interaction between risk factors could be effectively managed by an appropriate choice of both antihypertensive and lipid-lowering drugs.

Effect of pravastatin on proteinuria in patients with well-controlled hypertension

Proteinuria is an important risk factor for cardiovascular and renal morbidity and mortality. The effects of 3-hydroxy-3-methyglutaryl coenzyme A reductase inhibitor (statin) therapy on proteinuria in normolipidemic patients with well-controlled hypertension have not been studied. A total of 63 normolipidemic (total cholesterol <240 mg/dL) and proteinuric (300 to 3000 mg/d) patients with well-controlled blood pressure (<140/90 mm Hg) were randomized to receive either placebo (n=32) or pravastatin (10 mg/d; n=31) after a 3-month placebo period. Pravastatin lowered proteinuria after 6 months by 54% (P<0.0001). Creatinine clearance was stable throughout the study in the 2 groups. Despite unchanged plasma endothelin-1 levels throughout the study, urinary excretion of the peptide was decreased and significantly correlated with improvement in urinary protein excretion in pravastatin-treated patients (r=0.64, P=0.001). The urinary excretion of retinol-binding protein decreased after pravastatin administration, probably reflecting an improvement in tubular function. In contrast, the urinary excretion of IgG did not change significantly throughout the study in either group. Multivariate analysis revealed that proteinuria was only significantly correlated with statin use (P<0.0001, R2= 0.66). Linear regression analysis in the statin-treated group did not show any correlation between changes in lipid profiles and proteinuria regression. Thus, in addition to their primary function of antilipidemia, the addition of pravastatin to treatment for well-controlled hypertension may have an additive effect on reducing proteinuria independent of hemodynamics and lipid-lowering effects, possibly through inhibiting renal endothelin-1 synthesis and improving tubular function.

Use of lipid-lowering drugs and blood pressure control in patients with arterial hypertension

A large proportion of patients have both hypertension and hypercholesterolemia, two of the most important risk factors for cardiovascular diseases. Statins are the most widely used drugs for the treatment of plasma lipid abnormalities and have been reported to interact with elevated blood pressure. A reduction in blood pressure associated with the use of these agents has been reported in patients with untreated hypertension and in patients treated with antihypertensive drugs, particularly angiotensin-converting enzyme inhibitors and calcium channel blockers. This effect on blood pressure control has also been observed in diabetic patients. The mechanism responsible for the hypotensive effect seems to be largely independent of the effect of statins on plasma cholesterol, and probably is related to the interaction of the medications with endothelial function or angiotensin II receptors. The capacity of statins to improve blood pressure control may represent a useful tool for improvement in the prevention of cardiovascular diseases.

Increased central pulse pressure and augmentation index in subjects with hypercholesterolemia

OBJECTIVES

The goal of this study was to investigate the relation between serum cholesterol, arterial stiffness and central blood pressure.

BACKGROUND

Arterial stiffness and pulse pressure are important determinants of cardiovascular risk. However, the effect of hypercholesterolemia on arterial stiffness is controversial, and central pulse pressure has not been previously investigated.

METHODS

Pressure waveforms were recorded from the radial artery in 68 subjects with hypercholesterolemia and 68 controls, and corresponding central waveforms were generated using pulse wave analysis. Central pressure, augmentation index (AIx) (a measure of systemic stiffness) and aortic pulse wave velocity were determined.

RESULTS

There was no significant difference in peripheral blood pressure between the two groups, but central pulse pressure was significantly higher in the group with hypercholesterolemia (37 +/- 11 mm Hg vs. 33 +/- 10 mm Hg [means +/- SD]; p = 0.028). Augmentation index was also significantly higher in the patients with hypercholesterolemia group (24.8 +/- 11.3% vs. 15.6 +/- 12.1%; p < 0.001), as was the estimated aortic pulse wave velocity. In a multiple regression model, age, short stature, peripheral mean arterial pressure, smoking and low-density lipoprotein cholesterol correlated positively with AIx, and there was an inverse correlation with heart rate and male gender.

CONCLUSIONS

Patients with hypercholesterolemia have a higher central pulse pressure and stiffer blood vessels than matched controls, despite similar peripheral blood pressures. These hemodynamic changes may contribute to the increased risk of cardiovascular disease associated with hypercholesterolemia, and assessment may improve risk stratification.