Short-term effect of low-dose atorvastatin on haemorrheological parameters, platelet aggregation and endothelial function in patients with cerebrovascular disease and hyperlipidaemia

Association of HMGCR rs17671591 and rs3761740 with lipidemia and statin response in Uyghurs and Han Chinese

Background

Dyslipidemia plays a very important role in the occurrence and development of cardiovascular disease (CVD). Genetic factors, including single nucleotide polymorphisms (SNPs), are one of the main risks of dyslipidemia. 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) is not only the rate-limiting enzyme step of endogenous cholesterol production, but also the therapeutic target of statins.

Methods

We investigated 405 Han Chinese and 373 Uyghur people who took statins for a period of time, recorded their blood lipid levels and baseline data before and after oral statin administration, and extracted DNA from each subject for SNP typing of HMGCR rs17671591 and rs3761740. The effects of HMGCR rs17671591 and rs3761740 on lipid levels and the effect of statins on lipid lowering in Han Chinese and Uyghur ethnic groups were studied.

Results

In this study, for rs17671591, the CC vs. TT+CT model was significantly correlated with the level of LDL-C before oral statin in the Uyghur population, but there were no correlations between rs17671591 and the level of blood lipid before oral statin in the Han population. The CC vs. TT+CT and CT vs. CC+TT models were significantly correlated with the level of LDL-C after oral statin in the Uyghur population. There was no significant correlation between rs3761740 with blood lipids before and after oral statin in the Han population. For rs3761740, before oral statin, the CC vs. AA+CA model was significantly correlated with the level of LDL-C, and the CA vs. CC+AA model was significantly correlated with the level of total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), and non-high density lipoprotein cholesterol (HDL-C) in the Uyghur population. After oral statin, the CC vs. AA+CA and CA vs. CC+AA models were significantly correlated with the level of TC, LDL-C, and apolipoprotein (APOB), and the C vs. A model was significantly correlated with the level of TC, triglyceride (TG), LDL-C, and APOB in the Uyghur population. Particularly, the CT vs. CC+TT model of rs17671591 was significantly correlated with the changes of LDL-C after oral statin in the Uyghur population. In this study, we also explored the association of rs17671591 and rs3761740 with the rate of dyslipidemia as a reference.

Conclusion

We found that HMGCR rs3761740 was correlated with the levels of TC, LDL-C, and non-HDL-C before and after oral statin in Uyghurs, but not with blood lipid levels in the Han population. In the Uyghur population, HMGCR rs17671591 was associated with the level of LDL-C before and after oral statin, and also affected the changes of LDL-C after oral statin.

Effect of statin therapy patterns on readmission and mortality in patients with intracerebral hemorrhage

There is limited and inconsistent evidence for the association of statin therapy and statin treatment patterns with the risk of recurrent intracerebral hemorrhage (ICH) in patients with prior ICH. To assess the association of statin therapy and its intensity, type, initiation time, and discontinuation with the risk of recurrent ICH and mortality in Chinese patients with ICH. Patients with newly diagnosed ICH in the Beijing Employee Medical Claims Data database from 2010 to 2017 were included. Post-ICH statin users (post-diagnosis only) and nonusers (never), statin discontinuers (pre-diagnosis only) and continuers (pre- and post-diagnosis) were matched on a 1:1 propensity score, respectively. Adjusted Cox proportional risk models were used to estimate the risk ratios for ICH readmission and mortality under various statin patterns. A total of 2668 post-ICH statin users and 2668 nonusers without a history of statin use were enrolled. Post-ICH statin users had a lower risk of ICH readmission (HR, 0.57; 95% CI 0.48, 0.69) and all-cause death (0.56: 0.49, 0.63) than nonusers. Low/moderate-intensity treatment was associated with a 63% lower risk of recurrent ICH compared with nonusers (0.37: 0.29, 0.46), whereas high-intensity treatment did not reduce the risk (0.93: 0.74, 1.16). Both low/moderate-intensity (0.42: 0.36, 0.48) and high-intensity statins (0.57: 0.48, 0.69) were associated with a lower risk of all-cause mortality. The risk of ICH readmission was 53% (0.47: 0.30, 0.74) lower with adherence to rosuvastatin than with atorvastatin. Only starting medication within 30 days of the first diagnosis of ICH reduced the risk of ICH readmission (0.49: 0.40, 0.60). Among patients with a history of statin use, 1807 discontinuing and 1,807 continuing users of statins were included. The risk of ICH readmission (4.00: 3.32, 4.80) and the risk of all-cause death (4.01: 3.57, 4.50) were substantially increased in statin discontinuation compared with continued statin use. Statin therapy after ICH was associated with lower risks for ICH readmission and all-cause mortality compared with non-statin therapy, especially at low/moderate intensity and early initiation of statins after ICH. Adherence to rosuvastatin was associated with a lower risk of recurrence of ICH than atorvastatin. Among patients with a statin history prior to ICH, discontinuation of statins after ICH was associated with increased risk of ICH recurrence and death.

Is statin therapy after ischaemic stroke associated with increased intracerebral hemorrhage? The association may be dependent on intensity of statin therapy

BACKGROUND

There has been concern that statin therapy may be associated with an increased risk of intracerebral hemorrhage (ICH). We investigated whether the intensity and type of statin therapy instituted after ischemic stroke (IS) were associated with risk of future ICH in a region of northern China with a high incidence of stroke.

METHODS

Newly diagnosed IS patients who were not treated with lipid-lowering drugs in the Beijing Employee Medical Claims Data database from 2010 to 2017 were included. The primary exposure variable was any statin prescription within 1 month of the first documented stroke diagnosis. High-intensity statin therapy was defined as atorvastatin ⩾ 80 mg, simvastatin ⩾ 80 mg, pravastatin ⩾ 40 mg, and rosuvastatin ⩾ 20 mg per day or equivalent combination. An adjusted Cox proportional hazards model was used to estimate the hazard ratio (HR) for ICH during follow-up in groups exposed and not exposed to statins.

RESULTS

Of 62,252 participants with IS and 628 ICH readmissions were recorded during a median follow-up of 3.17 years. The risk of ICH among statin users (N = 43,434) was similar to that among nonusers (N = 18,818) with an adjusted HR and 95% confidence interval (CI) of 0.86 (0.73, 1.02). Compared with non-statin therapy, patients with low/moderate-intensity therapy had a lower risk of ICH (0.62: 0.52, 0.75), while patients with high-intensity therapy had a substantially higher risk (2.12: 1.72, 2.62). For patients with different types of statin therapy, adherence to rosuvastatin had the lowest risk of ICH compared to adherence to atorvastatin (0.46: 0.34, 0.63), followed by simvastatin (0.60: 0.45, 0.81).

CONCLUSION

In patients with IS, any statin therapy was not associated with an increased risk of ICH. However there appeared to be differential risk according to the dose of statin with high-intensity statin therapy being associated with an increased risk of ICH, while low/moderate-intensity therapy was associated with a lower risk.

Diet-Dependent and Diet-Independent Hemorheological Alterations in Celiac Disease: A Case-Control Study

Hemorheology is the study of the flow properties of the blood and its elements, which, together with natural anticoagulants, are important determinants of cardiovascular events. This study aimed to assess hemorheological and natural anticoagulant profiles of patients with celiac disease (CeD) comprehensively.

The Benefits and Risks of Statin Therapy in Ischemic Stroke: A Review of the Literature

Statins are effective cholesterol-lowering drugs for reducing the risks of mortality and morbidity of cardiovascular diseases. Increasing evidence has shown that statin use is associated with a significant beneficial effect in patients with ischemic stroke. Both pre-stroke and post-stroke statin use has been found to be beneficial in ischemic stroke. Furthermore, good adherence is associated with a better clinical outcome, and statin withdrawal is associated with a poor functional outcome in patients with ischemic stroke. High-intensity statin therapy is advocated for the treatment of ischemic stroke. However, there are concerns regarding the adverse effects associated with statin use in ischemic stroke such as intracranial hemorrhage. In this review, we summarize the beneficial effect of statin use in ischemic stroke and discuss the potential risks associated with statin therapy.

Simvastatin Effects on Inflammation and Platelet Activation Markers in Hypercholesterolemia

Background

Beside the lipid-lowering effect, statins slow the progression of atherosclerosis by exerting anti-inflammatory and platelet inhibiting effects. We investigated whether platelet inhibition by simvastatin correlates with the statin effects on lipid lowering, inflammation, oxidative stress, and endothelial and platelet activation.

Methods

In hypercholesterolemic patients allocated to diet (n=20) or a 2-month treatment with diet plus 40 mg simvastatin (n=25), we evaluated platelet aggregating responses to ADP, collagen, and arachidonic acid (AA), the effect of aspirin on AA-induced aggregation, pro- and anti-inflammatory and atherogenic mediators (IL-1β, -5, -6, -7, -8, -9, -10, -12, and -13, IFN-γ, IP-10, Eotaxin, and sRAGE), markers of endothelium (sE-selectin, VEGF, and MCP-1) and platelet activation (sP-selectin, sCD-40L, RANTES, and PDGF-bb), and oxidative stress (8-OH-2'-deoxyguanosine).

Results

After treatment, beside the improvement of lipid profile, we observed the following: a reduction of platelet aggregation to ADP (p=0.0001), collagen (p=0.0001), AA (p=0.003); an increased antiaggregating effect of aspirin in the presence of AA (p=0.0001); a reduction of circulating levels of IL-6 (p=0.0034), IL-13 (p<0.0001), IFN-γ (p<0.0001), VEGF (p<0.0001), sE-selectin (p<0.0001), sCD-40L (p<0.0001), sP-selectin (p=0.003), and 8-OH-2'-deoxyguanosine (p<0.0001); an increase of IL-10 and sRAGEs (p=0.0001 for both). LDL-cholesterol levels (i) positively correlated with IL-6, IFN-γ, E-selectin, sCD-40L, 8-OH-2'-deoxyguanosine, platelet aggregation to ADP, collagen, AA, and aspirin IC-50 and (ii) negatively correlated with IL-10 and sRAGE. In multiple regression analyses, LDL-cholesterol was the strongest predictor for most parameters of platelet reactivity.

Conclusion

In primary hypercholesterolemia, simvastatin treatment reduced platelet activation and subclinical inflammation and improved endothelial dysfunction. LDL-cholesterol levels were the major correlate of platelet reactivity; however, other effects of statins may contribute to reducing the progression of atherosclerosis.

Platelet reactivity in response to loading dose of atorvastatin or rosuvastatin in patients with stable coronary disease before percutaneous coronary intervention: The STATIPLAT randomized study

BACKGROUND

The acute effects of statin loading dose (LD) on platelet reactivity in patients with chronic stable angina (CSA) are not completely clear.

HYPOTHESIS

We hypothesized that LDs of atorvastatin and rosuvastatin have different pharmacodynamic acute effects on platelet aggregability in CSA patients with baseline normal platelet reactivity while on dual antiplatelet therapy (DAPT).

METHODS

From September 2011 to February 2014, all consecutive CSA patients on chronic DAPT (aspirin and clopidogrel) were evaluated before elective percutaneous coronary intervention (PCI). An initial assessment of platelet reactivity in response to thrombin receptor agonist, ADP, and ASP (respectively, indicative of the response to clopidogrel and aspirin) was performed with impedance aggregometry. Patients with high platelet reactivity to ADP test (area under the curve >47) were excluded. The remaining patients were randomized into 3 treatment groups: Group A, atorvastatin LD 80 mg; Group B, rosuvastatin LD 40 mg; and Group C, no statin LD (control group). A second assessment of platelet reactivity was performed ≥12 hours after statin LD.

RESULTS

682 patients were screened and 145 were randomized into the 3 groups. At baseline and after statin LD, no significant difference was found in platelet reactivity in response to 3 different agonists between the 3 groups. Subgroup analysis showed that platelet reactivity to ADP test was significantly lower in patients chronically treated with low-dose statins (n = 94) compared with statin-naïve patients (n = 51; 15.32 ± 1.50 vs 18.59 ± 1.30; P = 0.007).

CONCLUSIONS

Loading dose of atorvastatin (80 mg) or rosuvastatin (40 mg) did not induce significant variation in platelet reactivity in CSA patients with baseline reduced platelet reactivity as in chronic DAPT. Our data confirm that chronic concomitant treatment with low-dose statins and clopidogrel resulted in significantly lower platelet reactivity compared with clopidogrel alone.

The role of red blood cell deformability and Na,K-ATPase function in selected risk factors of cardiovascular diseases in humans: focus on hypertension, diabetes mellitus and hypercholesterolemia

Deformability of red blood cells (RBC) is the ability of RBC to change their shape in order to pass through narrow capillaries in circulation. Deterioration in deformability of RBC contributes to alterations in microcirculatory blood flow and delivery of oxygen to tissues. Several factors are responsible for maintenance of RBC deformability. One of them is the Na,K-ATPase known as crucial enzyme in maintenance of intracellular ionic homeostasis affecting thus regulation of cellular volume and consequently RBC deformability. Decreased deformability of RBC has been found to be the marker of adverse outcomes in cardiovascular diseases (CVD) and the presence of cardiovascular risk factors influences rheological properties of the blood. This review summarizes knowledge concerning the RBC deformability in connection with selected risk factors of CVD, including hypertension, hyperlipidemia, and diabetes mellitus, based exclusively on papers from human studies. We attempted to provide an update on important issues regarding the role of Na,K-ATPase in RBC deformability. In patients suffering from hypertension as well as diabetes mellitus the Na,K-ATPase appears to be responsible for the changes leading to alterations in RBC deformability. The triggering factor for changes of RBC deformability during hypercholesterolemia seems to be the increased content of cholesterol in erythrocyte membranes.

Statin use after intracerebral hemorrhage: a 10-year nationwide cohort study

INTRODUCTION

Although statin therapy is beneficial to patients with ischemic stroke, statin use, and intracerebral hemorrhage (ICH) remain a concern. ICH survivors commonly have comorbid cardiovascular risk factors that would otherwise warrant cholesterol-lowering medication, thus emphasizing the importance of assessing the characteristics of statin therapy in this population.

METHODS

We performed a cohort study by using 10 years of data collected from the National Health Insurance Research Database in Taiwan. We enrolled 726 patients admitted for newly diagnosed ICH from January 1, 2001 to December 31, 2010. The patients were categorized into high- (92), moderate- (545), and low-intensity (89) statin groups, and into hydrophilic (295) and lipophilic (431) statin groups. The composite outcomes included all-cause mortality, recurrent ICH, ischemic stroke, transient ischemic attack, and acute coronary events.

RESULTS

The patients in the low-intensity group did not differ significantly from the patients in the high-intensity group in risk of all-cause mortality (adjusted hazard ratio [aHR] = 0.65, 95% confidence interval [CI] = 0.28-1.55) and recurrent ICH (aHR = 0.66, 95% CI = 0.30-1.44). In contrast, the patients in the hydrophilic group had a significantly lower risk of recurrent ICH than did those in the lipophilic group (aHR = 0.69, 95% CI = 0.48-0.99). We determined no significant differences in other composite endpoints between hydrophilic and lipophilic statin use.

CONCLUSION

Hydrophilic statin therapy is associated with a reduced risk of recurrent ICH in post-ICH patients. The intensity of statin use had no significant effect on recurrent ICH or other components of the composite outcome. Additional studies are required to clarify the biological mechanisms underlying these observations.

High-dose statin therapy and risk of intracerebral hemorrhage: a meta-analysis

Statin plays a major role in the primary and secondary prevention of cardiovascular disease (CVD). Inconsistent findings in the studies have been observed toward the risk of intracerebral hemorrhage (ICH) using higher dose of statin. To examine this issue, we performed a meta-analysis of randomized controlled trials (RCTs) to assess the association between higher dose of various statins and risk of ICH among patients with CVD. Literature was searched for studies published before June 10, 2015, using electronic database 'PubMed', 'EMBASE', and 'Google Scholar' as well as from many trial databases. The following search terms were used: 'Statin therapy' AND 'Cardiovascular Disease', AND 'Dose' AND 'Intracerebral hemorrhage', AND 'Randomized Controlled Trials' AND 'High Dose Statin'. High dose of statins was defined as atorvastatin 80 mg, simvastatin 80 mg, pravastatin 40 mg, rosuvastatin 20 mg per day. Fixed-effect model was used to estimate the risk ratio (RR) and 95% confidence interval (CI) if heterogeneity was <50%; otherwise, random-effect model was used. Begg's funnel plot was used to assess the publication bias. Seven RCTs involving 31,099 subjects receiving high-dose statin and 31,105 subjects receiving placebo were analyzed in our meta-analysis. A significant risk of ICH was observed in subjects with higher dose of statin (RR = 1.53; 95% CI: 1.16-2.01; P = 0.002). There was no difference in all-cause mortality between the two groups (RR = 0.95; 95% CI: 0.86-1.06; P = 0.36). No publication bias was observed through Begg's funnel plot. Higher dose of statins was found to be associated with the risk of ICH. Future studies are needed to confirm these findings.

Statins and Risk of Bleeding: An Analysis to Evaluate Possible Bias Due to Prevalent Users and Healthy User Aspects

Statins are said to protect against a wide range of diseases. We studied to what extent potential bias influences the results of studies on beneficial side effects of statins. We selected 8,188 atrial fibrillation patients who started treatment with anticoagulants at the Leiden Anticoagulation Clinic in the Netherlands between 2003 and 2009 and experienced 1,683 minor and 451 major bleeds during 18,105 person-years of follow-up. Statins were associated with a risk reduction of 9% for bleeds (hazard ratio = 0.91, 95% confidence interval: 0.82, 1.00). Additionally, analyses were stratified by age, incident users (patients who started statins during follow-up, i.e., an inception cohort), and prevalent statin users (statin users at baseline), as restriction to incident users avoids overoptimistic risk estimates. After stratification, the protective associations disappeared or reversed (range of hazard ratios = 0.99-3.22), except for patients aged 75 years or older. This remaining association could be due to another bias as, according to guidelines, in the elderly, statins should be prescribed only to those with a reasonable life expectancy. This could have resulted in a comparison of fit statin users with less fit nonstatin users (healthy user effect). The apparent protective association of statins on bleeds may be due to bias. We recommend stratification by age and incident and prevalent statin use when studying associations of statins with disease outcomes to avoid overoptimistic risk estimates.

HMGCR rs17671591 SNP Determines Lower Plasma LDL-C after Atorvastatin Therapy in Chilean Individuals

Lipid-lowering response to statin therapy shows large interindividual variability. At a genome-wide significance level, single nucleotide polymorphisms (SNPs) in PCSK9 and HMGCR have been implicated in this differential response. However, the influence of these variants is uncertain in the Chilean population. Hence, we aimed to evaluate the contribution of PCSK9 rs7552841 and HMGCR rs17671591 SNPs as genetic determinants of atorvastatin response in Chilean hypercholesterolaemic individuals. One hundred and one hypercholesterolaemic patients received atorvastatin 10 mg/day for 4 weeks. Plasma lipid profile (TC, HDL-C, LDL-C and TG) was determined before and after statin treatment, and SNPs were identified by allelic discrimination using TaqMan(®) SNP Genotyping Assays. Adjusted univariate and multivariate analyses' models were used for statistical analyses, and a p-value <0.05 was considered significant. From baseline (week 0) to the study end-point (week 4), significant reductions were observed in plasma TC, LDL-C and TG (p < 0.001), while HDL-C levels were increased (p < 0.001). Multivariate analysis showed no association between lipid levels and atorvastatin therapy for the PCSK9 variant. However, the HMGCR rs17671591 T allele contributed to basal HDL-C concentration variability along with a higher increase in this lipid fraction after statin medication. In addition, this allele determined greater plasma LDL-C reductions after therapy with atorvastatin. Our data suggest that the HMGCR rs17671591 polymorphism can constitute a genetic marker of lower plasma LDL-C and enhanced HDL-C concentration after atorvastatin therapy in the Chilean population.

Lipid-lowering efficacy of atorvastatin

BACKGROUND

This represents the first update of this review, which was published in 2012. Atorvastatin is one of the most widely prescribed drugs and the most widely prescribed statin in the world. It is therefore important to know the dose-related magnitude of effect of atorvastatin on blood lipids.

OBJECTIVES

Primary objective To quantify the effects of various doses of atorvastatin on serum total cholesterol, low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol and triglycerides in individuals with and without evidence of cardiovascular disease. The primary focus of this review was determination of the mean per cent change from baseline of LDL-cholesterol. Secondary objectives • To quantify the variability of effects of various doses of atorvastatin.• To quantify withdrawals due to adverse effects (WDAEs) in placebo-controlled randomised controlled trials (RCTs).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 11, 2013), MEDLINE (1966 to December Week 2 2013), EMBASE (1980 to December Week 2 2013), Web of Science (1899 to December Week 2 2013) and BIOSIS Previews (1969 to December Week 2 2013). We applied no language restrictions.

SELECTION CRITERIA

Randomised controlled and uncontrolled before-and-after trials evaluating the dose response of different fixed doses of atorvastatin on blood lipids over a duration of three to 12 weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility criteria for studies to be included and extracted data. We collected information on withdrawals due to adverse effects from placebo-controlled trials.

MAIN RESULTS

In this update, we found an additional 42 trials and added them to the original 254 studies. The update consists of 296 trials that evaluated dose-related efficacy of atorvastatin in 38,817 participants. Included are 242 before-and-after trials and 54 placebo-controlled RCTs. Log dose-response data from both trial designs revealed linear dose-related effects on blood total cholesterol, LDL-cholesterol, HDL-cholesterol and triglycerides. The Summary of findings table 1 documents the effect of atorvastatin on LDL-cholesterol over the dose range of 10 to 80 mg/d, which is the range for which this systematic review acquired the greatest quantity of data. Over this range, blood LDL-cholesterol is decreased by 37.1% to 51.7% (Summary of findings table 1). The slope of dose-related effects on cholesterol and LDL-cholesterol was similar for atorvastatin and rosuvastatin, but rosuvastatin is about three-fold more potent. Subgroup analyses suggested that the atorvastatin effect was greater in females than in males and was greater in non-familial than in familial hypercholesterolaemia. Risk of bias for the outcome of withdrawals due to adverse effects (WDAEs) was high, but the mostly unclear risk of bias was judged unlikely to affect lipid measurements. Withdrawals due to adverse effects were not statistically significantly different between atorvastatin and placebo groups in these short-term trials (risk ratio 0.98, 95% confidence interval 0.68 to 1.40).

AUTHORS' CONCLUSIONS

This update resulted in no change to the main conclusions of the review but significantly increases the strength of the evidence. Studies show that atorvastatin decreases blood total cholesterol and LDL-cholesterol in a linear dose-related manner over the commonly prescribed dose range. New findings include that atorvastatin is more than three-fold less potent than rosuvastatin, and that the cholesterol-lowering effects of atorvastatin are greater in females than in males and greater in non-familial than in familial hypercholesterolaemia. This review update does not provide a good estimate of the incidence of harms associated with atorvastatin because included trials were of short duration and adverse effects were not reported in 37% of placebo-controlled trials.

Effect of statins on platelet function in patients with hyperlipidemia

INTRODUCTION

It is generally assumed that cholesterol reduction by statins is the predominant therapeutic result underlying their beneficial effects in cardiovascular disease. However, the action of statins may be partially independent of their effects on plasma cholesterol levels, as they combine lipid lowering with positive effects on hemorheological conditions and endothelial function. We evaluated the impact of statin treatment on platelet adhesion to fibrinogen (spontaneous and ADP-activated), along with ADP, collagen or ristocetin-induced aggregation in type II hyperlipidemic patients.

MATERIAL AND METHODS

The study group included 70 persons: 50 patients affected by type II hyperlipidemia without concomitant diseases and 20 healthy volunteers. The effects of 8-week statin treatment (atorvastatin 10 mg/day, simvastatin 20 mg/day, or pravastatin 20 mg/day) on platelet activation were evaluated.

RESULTS

Regardless of the type of statin, a significant decrease in ADP-induced platelet aggregation was observed: for atorvastatin 50.6 ±12.8% vs. 41.1 ±15.8% (p < 0.05), for simvastatin 57.2 ±18.0% vs. 44.7 ±22.1% (p = 0.05), and for pravastatin 55.8 ±19.5% vs. 38.8 ±23.3% (p < 0.05). There was no significant effect of statins on collagen or ristocetin-induced platelet aggregation and adhesion.

CONCLUSIONS

Therapy with statins beneficially modifies ADP-induced platelet aggregation in patients with hyperlipidemia and does not affect spontaneous or ADP-induced platelet adhesion to fibrinogen and platelet aggregation induced by collagen or ristocetin.

Lipid lowering efficacy of atorvastatin

BACKGROUND

Atorvastatin is one of the most widely prescribed drugs and the most widely prescribed statin in the world. It is therefore important to know the dose-related magnitude of effect of atorvastatin on blood lipids.

OBJECTIVES

To quantify the dose-related effects of atorvastatin on blood lipids and withdrawals due to adverse effects (WDAE).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library Issue 4, 2011, MEDLINE (1966 to November 2011), EMBASE (1980 to November 2011), ISI Web of Science (1899 to November 2011) and BIOSIS Previews (1969 to November 2011). No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled and uncontrolled before-and-after trials evaluating the dose response of different fixed doses of atorvastatin on blood lipids over a duration of 3 to 12 weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. WDAE information was collected from the placebo-controlled trials.

MAIN RESULTS

Two hundred fifty-four trials evaluated the dose-related efficacy of atorvastatin in 33,505 participants. Log dose-response data revealed linear dose-related effects on blood total cholesterol, low-density lipoprotein (LDL)-cholesterol and triglycerides. Combining all the trials using the generic inverse variance fixed-effect model for doses of 10 to 80 mg/day resulted in decreases of 36% to 53% for LDL-cholesterol. There was no significant dose-related effects of atorvastatin on blood high-density lipoprotein (HDL)-cholesterol. WDAE were not statistically different between atorvastatin and placebo for these short-term trials (risk ratio 0.99; 95% confidence interval 0.68 to 1.45).

AUTHORS' CONCLUSIONS

Blood total cholesterol, LDL-cholesterol and triglyceride lowering effect of atorvastatin was dependent on dose. Log dose-response data was linear over the commonly prescribed dose range. Manufacturer-recommended atorvastatin doses of 10 to 80 mg/day resulted in 36% to 53% decreases of LDL-cholesterol. The review did not provide a good estimate of the incidence of harms associated with atorvastatin because of the short duration of the trials and the lack of reporting of adverse effects in 37% of the placebo-controlled trials.

Delayed cerebral ischaemia after subarachnoid haemorrhage: looking beyond vasospasm

Despite improvements in the clinical management of aneurysmal subarachnoid haemorrhage over the last decade, delayed cerebral ischaemia (DCI) remains the single most important cause of morbidity and mortality in those patients who survive the initial bleed. The pathological mechanisms underlying DCI are still unclear and the calcium channel blocker nimodipine remains the only therapeutic intervention proven to improve functional outcomes after SAH. The recent failure of the drug clazosentan to improve functional outcomes despite reducing vasoconstriction has moved the focus of research into DCI away from cerebral artery constriction towards a more multifactorial aetiology. Novel pathological mechanisms have been suggested, including damage to cerebral tissue in the first 72 h after aneurysm rupture ('early brain injury'), cortical spreading depression, and microthrombosis. A greater understanding of the significance of these pathophysiological mechanisms and potential genetic risk factors is required, if new approaches to the prophylaxis, diagnosis, and treatment of DCI are to be developed. Furthermore, objective and reliable biomarkers are needed for the diagnosis of DCI in poor grade SAH patients requiring sedation and to assess the efficacy of new therapeutic interventions. The purpose of this article is to appraise these recent advances in research into DCI, relate them to current clinical practice, and suggest potential novel avenues for future research.

Secondary prevention of stroke: Pleiotropic effects of optimal oral pharmacotherapy

Stroke is a major cause of mortality and disability worldwide. During the past three decades, major advances have occurred in secondary prevention, which have demonstrated the broader potential for the prevention of stroke. Risk factors for stroke include previous stroke or transient ischemic attack, hypertension, high blood cholesterol and diabetes. Proven secondary prevention strategies are anti-platelet agents, antihypertensive drugs, statins and glycemic control. In the present review, we evaluated the secondary prevention of stroke in light of clinical studies and discuss new pleiotropic effects beyond the original effects and emerging clinical evidence, with a focus on the effect of optimal oral pharmacotherapy.

Clinical neuroprotective drugs for treatment and prevention of stroke

Stroke is an enormous public health problem with an imperative need for more effective therapies. In therapies for ischemic stroke, tissue plasminogen activators, antiplatelet agents and anticoagulants are used mainly for their antithrombotic effects. However, free radical scavengers, minocycline and growth factors have shown neuroprotective effects in the treatment of stroke, while antihypertensive drugs, lipid-lowering drugs and hypoglycemic drugs have shown beneficial effects for the prevention of stroke. In the present review, we evaluate the treatment and prevention of stroke in light of clinical studies and discuss new anti-stroke effects other than the main effects of drugs, focusing on optimal pharmacotherapy.

Statin use following intracerebral hemorrhage: a decision analysis

CONTEXT

Statins are widely prescribed for primary and secondary prevention of ischemic cardiac and cerebrovascular disease. Although serious adverse effects are uncommon, results from a recent clinical trial suggested increased risk of intracerebral hemorrhage (ICH) associated with statin use. For patients with baseline elevated risk of ICH, it is not known whether this potential adverse effect offsets the cardiovascular and cerebrovascular benefits.

OBJECTIVE

To address the following clinical question: Given a history of prior ICH, should statin therapy be avoided?

DESIGN

A Markov decision model was used to evaluate the risks and benefits of statin therapy in patients with prior ICH.

MAIN OUTCOME MEASURE

Life expectancy, measured as quality-adjusted life-years. We investigated how statin use affects this outcome measure while varying a range of clinical parameters, including hemorrhage location (deep vs lobar), ischemic cardiac and cerebrovascular risks, and magnitude of ICH risk associated with statins.

RESULTS

Avoiding statins was favored over a wide range of values for many clinical parameters, particularly in survivors of lobar ICH who are at highest risk of ICH recurrence. In survivors of lobar ICH without prior cardiovascular events, avoiding statins yielded a life expectancy gain of 2.2 quality-adjusted life-years compared with statin use. This net benefit persisted even at the lower 95% confidence interval of the relative risk of statin-associated ICH. In patients with lobar ICH who had prior cardiovascular events, the annual recurrence risk of myocardial infarction would have to exceed 90% to favor statin therapy. Avoiding statin therapy was also favored, although by a smaller margin, in both primary and secondary prevention settings for survivors of deep ICH.

CONCLUSIONS

Avoiding statins should be considered for patients with a history of ICH, particularly those cases with a lobar location.

Early outcome of acute ischemic stroke in hyperlipidemic patients under atorvastatin versus simvastatin

BACKGROUND

Studies designed to evaluate the efficacy of atorvastatin on stroke suggest that, in addition to cholesterol lowering, this drug may play a role in poststroke neuroprotection. The objective of this historical-prospective study was to analyze the efficacy of atorvastatin (40-80 mg) or simvastatin (at an optimal dose) during the first 2 weeks after stroke in hyperlipidemic patients treated with simvastatin before stroke onset.

METHODS

Medical records of all adult (aged >18 years) patients diagnosed with acute stroke were reviewed. Subjects were categorized on the basis of poststroke treatment exposure: atorvastatin (40 or 80 mg) or simvastatin (at an optimal dose). Each patient was examined using the National Institutes of Health Stroke Scale (NIHSS) and the modified Rankin Scale (mRS). Blood lipid profile was determined. All tests were performed at baseline and at 4 weeks after stroke.

RESULTS

A total of 371 patients (249 male and 122 female) were included. Subjects who received simvastatin were significantly older than those who received either dose of atorvastatin. Baseline differences in functional scores were not detected across treatment groups. Two weeks after stroke, subjects exposed to simvastatin had significantly poorer NIHSS and mRS scores than did subjects exposed to either atorvastatin dose. Atorvastatin 80 mg was associated with significantly better outcome compared with either of the other treatment groups. These differences persisted even after controlling for age and baseline scores.

CONCLUSIONS

Early outcome measured by NIHSS and mRS was better in acute stroke patients treated with atorvastatin than in those treated with simvastatin. These differences may reflect a neuroprotective effect unique to atorvastatin.

Prior statin use, intracranial hemorrhage, and outcome after intra-arterial thrombolysis for acute ischemic stroke

BACKGROUND AND PURPOSE

There are only limited data on whether prior statin use and/or cholesterol levels are associated with intracranial hemorrhage (ICH) and outcome after intra-arterial thrombolysis. The purpose of this study was to evaluate the association of statin pretreatment and cholesterol levels with the overall frequency of ICH, the frequency of symptomatic ICH, and clinical outcome at 3 months.

METHODS

We analyzed 311 consecutive patients (mean age, 63 years; 43% women) who received intra-arterial thrombolysis.

RESULTS

Statin pretreatment was present in 18%. The frequency of any ICH was 20.6% and of symptomatic ICH 4.8%. Patients with any ICH were more often taking statins (30% versus 15%, P=0.005), more often had atrial fibrillation (45% versus 30%, P=0.016), had more severe strokes (mean National Institute of Health Stroke Scale score 16.5 versus 14.7, P=0.022), and less often good collaterals (16% versus 24%, P=0.001). Patients with symptomatic ICH were more often taking statins (40% versus 15%, P=0.009) and had less often good collaterals (0% versus 24%, P<0.001). Any ICH or symptomatic ICH were not associated with cholesterol levels. After multivariate analysis, the frequency of any ICH remained independently associated with previous statin use (OR, 3.1; 95% CI, 1.53 to 6.39; P=0.004), atrial fibrillation (OR, 2.5; CI, 1.35 to 4.75; P=0.004), National Institutes of Health Stroke Scale score (OR, 1.1; CI, 1.00 to 1.10; P=0.037), and worse collaterals (OR, 1.7; CI, 1.19 to 2.42; P=0.004). There was no association of outcome with prior statin use, total cholesterol level, or low-density lipoprotein cholesterol level.

CONCLUSIONS

Prior statin use, but not cholesterol levels on admission, is associated with a higher frequency of any ICH after intra-arterial thrombolysis without impact on outcome.

Effect of atorvastatin treatment on the hemorheological and hemostaseological parameters in chronic cerebrovascular patients

Cerebrovascularis betegekben gyakoriak a haemorrheologiai és haemostaseologiai paraméterek kóros eltérései. A statinok az ischaemiás stroke prevenciójában hatékonyan alkalmazható szerek, kedvező hatásuk hátterében a lipidszint csökkentése mellett egyéb tényezők is igazolhatók. Célok: Tanulmányukban a szerzők áttekintik az atorvastatin stroke-prevencióval, haemorrheologiai és haemostaseologiai hatásaival kapcsolatos irodalmi adatokat, hivatkozva egy korábbi vizsgálatuk eredményeire, mely kis dózisú atorvastatinkezelés rövid távú haemorrheologiai, valamint endothel-diszfunkcióra és a thrombocytaaggregációra gyakorolt effektusait vizsgálta. Módszerek: 27 krónikus, hyperlipidaemiás agyérbetegnél (átlagéletkor: 61 ± 8 év) meghatározták a szérumlipidszinteket, a haemorrheologiai paramétereket (haematocrit, plazmafibrinogén-koncentráció, plazma- és teljesvér-viszkozitás, vörösvértest-aggregáció és -deformabilitás), a thrombocytaaggregációt kiinduláskor, majd 1 és 3 hónappal napi 10 mg atorvastatinkezelést követően. Az endothel-diszfunkciót jelző von Willebrand-faktor aktivitását a kezelés előtt, majd 1 hónap múlva mérték meg. Eredmények: A plazmakoleszterin-szint átlagos csökkenése 1, illetve 3 hónap múlva egyaránt 28% volt ( p < 0,001), az LDL-koleszterin-szint 40%-kal, illetve 38%-kal ( p < 0,001) csökkent a kiindulási értékhez képest. Az atorvastatinkezelés a teljesvér-viszkozitást a 3. hónap végére, míg a vvt-deformabilitást már az első hónap végére szignifikánsan csökkentette ( p < 0,05). A kollagén indukálta thrombocytaaggregáció a kiindulási értékhez képest szignifikánsan csökkent ( p < 0,001) változatlan antiaggregációs kezelés mellett. Szintén szignifikánsan javult a von Willebrand-faktor-aktivitás már 1 hónapos kezelést követően ( p < 0,05). Következtetések: Mind az irodalmi, mind a szerzők saját eredményei az atorvastatin komplex, kedvező hatására utalnak. A lipidcsökkentő effektus mellett a kis dózisban és rövid ideig alkalmazott atorvastatin javítja a haemorrheologiai paramétereket, a thrombocytaaggregációt és az endothel-diszfunkciót.

The relationship between spontaneous echocontrast, transesophageal echocardiographic parameters, and blood hemoglobin levels

BACKGROUND

Spontaneous echocontrast (SEC) or "smoke" is an intracavitary echocardiographic finding seen in situations of stasis or low blood flow. Increased hematocrit and fibrinogen levels have been associated with SEC in prior studies. Whether low hemoglobin (Hb) levels are an independent predictor of lower prevalence of SEC is a question that remains unanswered.

METHODS

A total of 266 transesophageal echocardiographic (TEE) studies were reviewed. Hb levels within 1 month from the TEE study were used as the baseline Hb before the study (75% had Hb on the same day of the TEE study). Clinical characteristics and demographics, and all relevant TEE variables including left atrial (LA) size, LA appendage emptying velocity (LAAEV), and presence or absence of SEC, were obtained using electronic patient information system search of TEE reports. Multivariate regression analysis was performed to identify the independent predictors of SEC.

RESULTS

Two groups were analyzed SEC (n = 45) or no SEC (n = 221). Only 7 patients had both LA and right atrial SEC. On univariate analysis, male sex, greater age, prior coronary artery bypass grafting, low ejection fraction (<50%), atrial fibrillation, renal failure, aortic atheroma, dilated LA, and decreased LAAEV (<40 cm/s) predicted SEC whereas low Hb levels were significantly associated with a lower prevalence of SEC (P = .01). However, after adjusting for clinical and echocardiographic variables, low Hb levels did not independently predict absence of SEC. Low LAAEV (P < .001), dilated LA (P = .001), and prior statin therapy (P = .001) were the most powerful independent predictors of SEC.

CONCLUSION

A low Hb level is not associated with a lower prevalence of SEC when controlled for clinical and echocardiographic variables. Our study confirms the importance of LAAEV and dilated LA in determining presence of SEC, but also raises interesting questions of the relationship between statins and SEC that warrant further study.

Statin adverse effects : a review of the literature and evidence for a mitochondrial mechanism

HMG-CoA reductase inhibitors (statins) are a widely used class of drug, and like all medications, have potential for adverse effects (AEs). Here we review the statin AE literature, first focusing on muscle AEs as the most reported problem both in the literature and by patients. Evidence regarding the statin muscle AE mechanism, dose effect, drug interactions, and genetic predisposition is examined. We hypothesize, and provide evidence, that the demonstrated mitochondrial mechanisms for muscle AEs have implications to other nonmuscle AEs in patients treated with statins. In meta-analyses of randomized controlled trials (RCTs), muscle AEs are more frequent with statins than with placebo. A number of manifestations of muscle AEs have been reported, with rhabdomyolysis the most feared. AEs are dose dependent, and risk is amplified by drug interactions that functionally increase statin potency, often through inhibition of the cytochrome P450 3A4 system. An array of additional risk factors for statin AEs are those that amplify (or reflect) mitochondrial or metabolic vulnerability, such as metabolic syndrome factors, thyroid disease, and genetic mutations linked to mitochondrial dysfunction. Converging evidence supports a mitochondrial foundation for muscle AEs associated with statins, and both theoretical and empirical considerations suggest that mitochondrial dysfunction may also underlie many nonmuscle statin AEs. Evidence from RCTs and studies of other designs indicates existence of additional statin-associated AEs, such as cognitive loss, neuropathy, pancreatic and hepatic dysfunction, and sexual dysfunction. Physician awareness of statin AEs is reportedly low even for the AEs most widely reported by patients. Awareness and vigilance for AEs should be maintained to enable informed treatment decisions, treatment modification if appropriate, improved quality of patient care, and reduced patient morbidity.

Atorvastatin and cardiovascular risk in the elderly--patient considerations

Elderly individuals are at increased risk of coronary heart disease (CHD) and account for a majority of CHD deaths. Several clinical trials have assessed the beneficial effects of statins in individuals with, or at risk of developing, CHD. These trials provide evidence that statins reduce risk and improve clinical outcomes even in older patients; however, statin therapy remains under-utilized among the aged. Atorvastatin has been widely investigated among the older subjects and has the greatest magnitude of favorable effects on clinical outcomes of CHD. The pharmacokinetic properties of atorvastatin allow it to be used every other day, a factor which may decrease adverse events and be especially important in the elderly. The purpose of this article is to review the evidence available from randomized clinical trials regarding the safety and efficacy of atorvastatin in primary and secondary prevention of CHD and stroke in older patients and to discuss issues such as drug interactions, patient compliance and cost-effectiveness, which affect prescription of lipid-lowering therapy among older patients.

Effect of high dose statin therapy on platelet function; statins reduce aspirin-resistant platelet aggregation in patients with coronary heart disease

BACKGROUND

Current evidence supports the preventive role of statins on platelet aggregation in patients with coronary heart disease.

AIM

Our aim was to determine the effects of aggressive statin therapy on platelet function in patients with coronary heart disease.

MATERIAL AND METHODS

A total of 178 consecutive patients (37-68 years old, 35.9% women) with stable coronary artery disease (CAD) was enrolled in the study. Platelet function assays were realized by the Platelet Function Analyzer (PFA)-100 with collagen and epinephrine (Col/Epi) and collagen and ADP (Col/ADP) cartridges. Aspirin resistance was defined as having a closure time (CT) of <186 s with Col/Epi cartridges despite regular aspirin therapy. A statin therapy protocol applied to the patients with aspirin resistance for 3 months.

RESULTS

We determined that 20 (11.2%) of patients had aspirin resistance by the PFA-100. Mean closure time measured with the Col/ADP cartridges was 83 +/- 18 s (53-162 s). Of the patients 12 were not on a statin therapy and eight were taking 10 mg daily atorvastatin. After 3 months of 40 mg daily atorvastatin therapy 13 subjects with aspirin resistance became aspirin sensitive by PFA-100 (P < 0.0001). There was also a significant decrease in total and LDL cholesterol levels and an increase in HDL cholesterol at the third month of statin therapy (P < 0.0001 for all).

CONCLUSION

Statin therapy reduced the in vitro aspirin resistance in 65% of the patients after a therapy of 3 months. Further studies are needed to elucidate the mechanism of statins' effects on platelet reactivity.

Whole blood viscosity and arterial thrombotic events in patients with systemic lupus erythematosus

OBJECTIVE

To determine if whole blood viscosity (WBV), a rheologic variable contributing to risk of myocardial infarction and stroke in the general population, is elevated in patients with systemic lupus erythematosus (SLE), particularly SLE patients with a history of thrombotic or atherothrombotic events. Because the high rates of arterial and venous thrombosis in lupus cannot be explained by traditional risk factors, elevated WBV may be an easily measurable nontraditional risk factor to identify SLE patients at high risk for thrombotic events.

METHODS

Sixty SLE patients (30 with a history of a thrombotic event) and 20 matched controls were recruited into the study. The thrombosis group was further subdivided into an arterial thrombosis group (n = 17). WBV values were determined at 9 different shear rates (1, 2, 5, 10, 50, 100, 150, 300, and 1,000 seconds(-1)). WBV was then compared between groups by repeated-measures analysis of variance.

RESULTS

SLE patients with a history of arterial events had significantly elevated WBV relative to either controls (P = 0.022) or SLE patients without arterial events (P = 0.014). WBV in the total SLE group did not differ from controls. Differences in WBV were most prominent at lower shear rates (1, 2, 5, 10, 50, and 100 seconds(-1)). Anticoagulation, prednisone dose, and antiphospholipid antibodies did not significantly impact WBV.

CONCLUSION

Our study demonstrated that WBV is selectively elevated in patients with SLE with a history of arterial events. Although this association is striking, longitudinal studies are needed to assess the positive predictive value of WBV for atherothrombotic events in SLE.

Does statin therapy decrease the risk for bleeding in patients who are receiving warfarin?

PURPOSE

Recent observations in patients with atrial fibrillation who are receiving warfarin suggest that concomitant treatment with a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) decreases the risk for bleeding.

METHODS

We conducted a population-based, nested case-control study using the linked administrative databases of Ontario, Canada, to assess whether statin use decreases the risk of bleeding in warfarin users. Eligible patients were Ontario residents, age 66 years or more, with atrial fibrillation who were prescribed warfarin between April 1, 1994, and December 31, 2001. Patients were followed until hospitalization for upper gastrointestinal or intracranial bleeding, study end (March 31, 2002), discontinuation of warfarin, or death. Cases were matched to controls by age and sex. Logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between bleeding and statin use.

RESULTS

We identified 79,207 warfarin users with atrial fibrillation. There were 1518 cases with an upper gastrointestinal or intracranial bleed and 15,100 matched controls without bleeding. Long-term (>/=1 year) statin use was associated with a lower risk for any bleeding (OR=0.80; 95% CI, 0.66-0.97). However, there was no association between bleeding and recent (<6 months) statin use (OR=1.04; 95% CI, 0.74-1.48) or statin use of any duration (OR: 0.91; 95% CI, 0.77-1.07), suggesting potential confounding of the association between statin use and bleeding by a health-user effect.

CONCLUSION

Long-term statin use may be associated with a decreased risk for bleeding in warfarin users with atrial fibrillation. Additional research is needed to further explore this putative association.

Improving Effects of Epigallocatechin-3-Gallate on Hemorheological Abnormalities of Aging Guinea Pigs

BACKGROUND

Epigallocatechin-3-gallate (EGCG) is the most potent antioxidant of all the green tea catechins. The objective of the present study was to find out whether it improved the age-induced hemorheological abnormalities or not.

METHODS AND RESULTS

Twenty-four-month-old aging guinea pigs were used to test the effects of EGCG on hemorheological properties. Orally feeding EGCG at 30 mg x kg(-1) x day (-1) for 28 days resulted in a decrease in erythrocyte membrane malondialdehyde, and further improved erythrocyte deformability and blood viscosity at high and middle shear rates. In addition, it also significantly reduced erythrocyte aggregation, and improved blood viscosity at low shear rates and viscoelasticity at oscillatory flow. Consequently, efficiency of blood oxygen transport in aged guinea pigs increased after administration with EGCG.

CONCLUSIONS

Orally feeding EGCG 30 mg x kg(-1) x day(-1) for 28 days significantly improves the abnormal hemorheological parameters. These results suggest that EGCG has considerable potential as a substantial component for the development of new drugs or functional foods in improving the age-induced hemorheological abnormalities.