The Effects of Atorvastatin Treatment on the Fibrinolytic System in Dyslipidemic Patients

Clot lysis time in platelet-rich plasma: method assessment, comparison with assays in platelet-free and platelet-poor plasmas, and response to tranexamic acid

Fibrinolysis dysfunctions cause bleeding or predisposition to thrombosis. Platelets contain several factors of the fibrinolytic system, which could up or down regulate this process. However, the temporal relationship and relative contributions of plasma and platelet components in clot lysis are mostly unknown. We developed a clot lysis time (CLT) assay in platelet-rich plasma (PRP-CLT, with and without stimulation) and compared it to a similar one in platelet-free plasma (PFP) and to another previously reported test in platelet-poor plasma (PPP). We also studied the differential effects of a single dose of tranexamic acid (TXA) on these tests in healthy subjects. PFP- and PPP-CLT were significantly shorter than PRP-CLT, and the three assays were highly correlated (p < 0.0001). PFP- and PPP-, but more significantly PRP-CLT, were positively correlated with age and plasma PAI-1, von Willebrand factor, fibrinogen, LDL-cholesterol, and triglycerides (p < 0.001). All these CLT assays had no significant correlations with platelet aggregation/secretion, platelet counts, and pro-coagulant tests to explore factor X activation by platelets, PRP clotting time, and thrombin generation in PRP. Among all the studied variables, PFP-CLT was independently associated with plasma PAI-1, LDL-cholesterol, and triglycerides and, additionally, stimulated PRP-CLT was also independently associated with plasma fibrinogen. A single 1 g dose of TXA strikingly prolonged all three CLTs, but in contrast to the results without the drug, the lysis times were substantially shorter in non-stimulated or stimulated PRP than in PFP and PPP. This standardized PRP-CLT may become a useful tool to study the role of platelets in clot resistance and lysis. Our results suggest that initially, the platelets enmeshed in the clot slow down the fibrinolysis process. However, the increased clot resistance to lysis induced by TXA is overcome earlier in platelet-rich clots than in PFP or PPP clots. This is likely explained by the display of platelet pro-fibrinolytic effects. Focused research is needed to disclose the mechanisms for the relationship between CLT and plasma cholesterol and its potential pathophysiologic and clinical relevance.

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.

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 on endothelial function and inflammation in long-duration type 1 diabetic patients without coronary heart disease and arterial hypertension

AIM

We evaluated the ability of atorvastatin, an HMG-CoA reductase inhibitor, to affect endothelial function and inflammation in long-duration (>10 years) type 1 diabetes mellitus (T1DM) patients without coronary heart disease (CHD) and arterial hypertension (AH).

METHODS AND RESULTS

We randomized 204 Caucasians with long-duration T1DM into either the atorvastatin 40 mg/day plus hypolipaemic diet group (n = 154) or the placebo plus hypolipaemic diet group (n = 50) for 6 months. Endothelium-dependent flow-mediated (FMD) and endothelium-independent flow-mediated vasodilatation, serum levels of plasminogen activator inhibitor-1 (PAI-1), von Willebrand factor (vWF) and high sensitivity C-reactive protein (hs-CRP) were estimated before and after treatment. After 6 months of therapy, FMD was increased by 44% in the atorvastatin plus diet group compared with the placebo plus diet group. Treatment with atorvastatin led to a significant reduction in levels of PAI-1 and hs-CRP; however, the elevation of vWF level was observed. In the placebo plus diet group, we observed a significant reduction in levels of hs-CRP but not of vWF and PAI-1.

CONCLUSIONS

Atorvastatin improves endothelial function and reduces some proinflammatory and prothrombotic markers of atherosclerosis in T1DM patients without CHD and AH. The surprising effect of atorvastatin on serum vWF levels in T1DM requires further study.

The nonlipid effects of statins on endothelial function

Hydroxymethylglutaryl-coenzyme A reductase inhibitors or statins constitute one of the wonder drugs of the last 2 decades. Use of this hypolipidemic medication class reduces morbidity and mortality in patients with a wide variety of cholesterol levels. Beneficial effects of the medication are seen in advance of changes in lipids suggesting nonlipid mechanisms may play a role in mediating these benefits of statins. One important nonlipid mechanism by which statins may improve vascular outcomes is restoration of normal endothelial cell function. This review will discuss the nonlipid effects of statins on endothelial cell function to highlight other avenues of benefit conferred by these medications.