Effects of atorvastatin on systemic inflammatory response after coronary bypass surgery

Simvastatin suppresses lung inflammatory response in a rat cardiopulmonary bypass model

BACKGROUND

Inflammatory response in the lungs is a well-known complication after cardiopulmonary bypass (CPB). The main aims of our study were to explore whether pretreatment with simvastatin would inhibit toll-like receptor 4 expression and suppress lung inflammatory response in a rat CPB model.

METHODS

Male Sprague-Dawley rats were divided into four groups (n = 6 each): sham group; CPB (control group); CPB plus low-dose simvastatin (5 mg/kg daily [L-Sim group]); and CPB plus high-dose simvastatin (10 mg/kg daily [H-Sim group]). Blood samples were collected at the beginning and at the termination of CPB, and at 1, 2, 4, and 24 hours after operation. The bronchoalveolar lavage fluid and lungs were harvested 24 hours postoperatively.

RESULTS

The simvastatin-treated groups had significantly higher ratios of PaO(2)/FiO(2) and lower values of respiratory index than the control group. We observed that simvastatin reduced CPB-induced toll-like receptor 4 and nuclear factor-kappaB expressions in CPB groups (p < 0.01, versus control group). The levels of interleukin-6, tumor necrosis factor-alpha, and monocyte chemotactic protein-1 in serum, bronchoalveolar lavage fluid, and lung tissues increased in CPB groups, whereas pretreatment with simvastatins reduced these inflammatory marks in a dose-dependent manner (p < 0.01, versus control group). Furthermore, pretreatment with simvastatin had a lower lung injury score (p < 0.05, versus control group).

CONCLUSIONS

These findings suggest that simvastatin inhibited CPB-induced toll-like receptor 4 upregulation and nuclear factor-kappaB activation, efficaciously reduing the pulmonary inflammatory response after CPB.

Inflammatory Activation During Coronary Artery Surgery and Its Dose-Dependent Modulation by Statin/ACE-Inhibitor Combination

Background— On-pump coronary artery bypass graft (CABG) surgery triggers an inflammatory response (IR) which may impair revascularization. The study aimed at (1) characterizing the temporal profile of the IR by assaying appropriate markers in both systemic and coronary blood, and (2) determining whether (and which doses of) cardiovascular drugs known to have antiinflammatory properties, namely statins and ACE-inhibitors (ACEI), inhibit the response.

Methods and Results— Patients scheduled for CABG (n=22) were randomized to statin/ACEI combination treatment at standard doses (STD, ramipril 2.5/simvastatin 20 mg, or atorvastatin 10 mg), or at high doses (HiDo, ramipril 10 mg, or enalapril 20 mg/simvastatin 80 mg, or atorvastatin 40 mg). Plasma levels of interleukin 6, tumor necrosis factor alpha, E-selectin, von Willebrand factor (vWF), and sVCAM-1 were serially assayed (ELISA) before, during, and after CABG. Blood was drawn from an artery, a systemic vein, and the coronary sinus. Myocardial perfusion scans were obtained before and 2 months after surgery in 19 out of 22 subjects. In the STD group both IL-6 and TNF displayed striking increases which were similar at all sites and peaked 10 to 60 minutes after aortic declamping. Such increases were drastically attenuated in the HiDo group. Instead, only modest increases in venous E-selectin, vWF, and sVCAM-1 were observed. Scintigraphic ischemia scores were entirely normalized after versus before CABG in the HiDo but not in the STD treatment group.

Conclusions— On-pump CABG surgery is associated with an intense systemic inflammatory response, which can be almost completely prevented by early treatment with high (but not standard) doses of ACE-inhibitors and statins.

Observational Study on the Beneficial Effect of Preoperative Statins in Reducing Atrial Fibrillation After Coronary Surgery

BACKGROUND

Recent evidence supports the important role of inflammation in atrial fibrillation (AF) after coronary artery bypass grafting (CABG) and there is growing evidence that statin has cardiac antiarrhythmic effects. The aim of this study was to assess the efficacy of preoperative statins in preventing AF after CABG in a longitudinal observational study.

METHODS

Over a two-year period, 405 consecutive patients underwent isolated CABG procedures. Univariate analysis was performed exploring the relationship regarding statin use and AF development. A propensity score for treatment with statins was obtained from core patient characteristics. The role of statin therapy on postoperative AF was assessed by means of a conditional logistic model, while stratifying on the quintiles of the propensity score. All analysis was performed retrospectively.

RESULTS

Postoperative AF occurred in 29.5% of the patients with preoperative statin therapy compared with 40.9% of those patients without it (p = 0.021). No statistical differences among development of AF and type, dose, or duration of preoperative statin therapy were observed. Preoperative statins were associated with a 42% reduction in risk of AF development after CABG surgery (odds ratio [OR] 0.58, 95% confidence interval [CI] 0.37 to 0.91, p = 0.017, while stratifying on the propensity score). No different effect of statins on AF was observed with respect to age groups (< or = 70 and > 70 years) (interaction p = 0.711).

CONCLUSIONS

Preoperative statins may reduce postoperative AF after CABG. Patients undergoing elective revascularization may benefit from a preventive statin approach.

Renoprotective effect of preoperative statins in coronary artery bypass grafting

The renoprotective effect of preoperative statin use in coronary artery bypass grafting remains poorly defined. A retrospective review of 1,802 consecutive patients who underwent isolated coronary artery bypass grafting from January 2002 to October 2005 was performed. Of those, 1,039 patients were receiving statins preoperatively, and 763 patients were not. Two propensity score-matched cohorts each of 641 patients (statin and nonstatin groups) were constructed. Multivariate logistic regression analyses for matched patients and all patients were performed to investigate whether preoperative statin use was associated with the incidence of new renal insufficiency. In a matched analysis, the statin group had a lower incidence of new renal insufficiency than the nonstatin group (1.6% vs 3.9%, odds ratio 0.39, 95% confidential interval 0.18 to 0.82, p = 0.01). Multivariate logistic regression analysis including all patients also showed that preoperative statin use (odds ratio 0.54, 95% confidence interval 0.30 to 0.99, p = 0.047) was significantly associated with low incidence of new postoperative renal insufficiency. In conclusion, preoperative statin use may be renoprotective after coronary artery bypass grafting.

CRP, IL-6 and endothelin-1 levels in patients undergoing coronary artery bypass grafting. Do preoperative inflammatory parameters predict early graft occlusion and late cardiovascular events?

BACKGROUND

Inflammation is a major contributor to atherosclerotic vascular disease. Inflammatory parameters such as C-reactive protein (CRP) and Interleukin-6 (IL-6) have been shown to be strong predictors of cardiovascular events. The association between preoperative inflammatory parameters and early graft occlusion as well as cardiovascular events after coronary artery bypass grafting (CABG) has not, however, been fully elucidated. The aims of the present study were to prospectively investigate the prognostic value of the inflammatory parameters IL-6, CRP, and endothelin (ET-1) to predict early graft occlusion as well as late cardiovascular events after CABG.

METHODS

In the present study 99 patients undergoing CABG because of stable angina pectoris due to significant coronary artery disease were prospectively included. Coronary angiography was repeated 3 months after CABG in 81 patients in order to evaluate early graft occlusion. Blood samples were collected before CABG in all patients. Patients were followed up for a median of 5 (3-7) years after CABG.

RESULTS

Twenty-five patients (31%) had one or more occluded grafts at the 3-month control coronary angiography. The patients with occluded grafts had higher preoperative CRP and IL-6 levels in plasma [CRP 2.22 (1.11-4.47) mg/L vs. 1.23 (0.71-2.27) mg/L P=0.03] and [IL-6 2.88 (1.91-5.94) pg/mL vs. 2.15 (1.54-3.14) pg/mL P=0.006]. There were 23 late cardiovascular events among the 99 patients during the follow-up. Patients experiencing late cardiovascular events had higher preoperative IL-6 levels than those without late cardiovascular events [4.13 (1.83-5.87) pg/mL vs. 2.08 (1.53-2.29) pg/mL, P=0.002] whereas CRP levels did not differ significantly between the two groups [1.5 (0.79-4.41) mg/L vs. 1.33 (0.74-2.48) mg/L, P=0.41]. Looking at IL-6, a cut off value more than 3.8 pg/ml was associated with a significant higher risk for an early graft occlusion (P=0.04) and late cardiovascular events (P=0.00003). Preoperative endothelin-1 did not predict early graft occlusions or late cardiovascular events.

CONCLUSIONS

Raised preoperative IL-6 levels are predictors of both early graft occlusion and late cardiovascular events after CABG. Elevated preoperative CRP levels can predict early graft occlusion after CABG. Endothelin did not differ between the two groups.

The relationship between statin use and atrial fibrillation

OBJECTIVE

To investigate the relationship between statin therapy and the development of new-onset, recurrent, and postoperative atrial fibrillation (AF).

RESEARCH DESIGN AND METHODS

A systematic literature search was conducted through September 2006. Included studies were either randomized, controlled trials or observational studies with adjusted analyses using multivariate regression or covariate matching, compared patients receiving or not receiving a statin, and reported data on the incidence of AF. Weighted averages were reported as odds ratios with 95% confidence intervals (CIs) using a random-effects model.

MAIN OUTCOME MEASURES

The primary outcome measured was a combined endpoint of any AF type. Secondary outcomes included new-onset, recurrent, and postoperative AF.

RESULTS

Fourteen trials reporting the results of 15 unique analyses (n = 7402) were included. There was a 20% incidence rate for any AF with varying rates depending on AF type (new-onset [11%], recurrent [56%], recurrent after cardioversion [54%], postoperative [22%]). The use of a statin reduced the odds of developing any AF by 45% (odds ratio [OR] 0.55; 95% CI 0.43-0.70); Q statistic p = 0.001). Statins reduced the odds of developing new-onset AF by 32% (OR 0.68; 95% CI 0.51-0.90), recurrent AF by 57% (OR 0.43; 95% CI 0.24-0.79), recurrent AF after cardioversion by 42% (OR 0.58; 95% CI 0.32-1.05) and postoperative AF by 58% (OR 0.42; 95% CI 0.27-0.65).

LIMITATIONS

We considered studies that were observational in nature or only available in abstract form. Publication bias could not be ruled out.

CONCLUSIONS

Statin therapy was associated with a reduced odds of developing AF, thus providing evidence of the benefit of statins beyond the lipid-lowering activity.

Simvastatin Increases Neutrophil Apoptosis and Reduces Inflammatory Reaction After Coronary Surgery

BACKGROUND

Neutrophils play a central role in systemic inflammatory reaction after cardiopulmonary bypass. Apoptosis is significantly delayed, and this might exacerbate systemic and myocardial damage. We tested the hypothesis of whether pretreatment with simvastatin increases the apoptotic rate of neutrophils and hence reduces the entity of inflammatory reaction.

METHODS

Thirty patients undergoing coronary surgery with cardiopulmonary bypass were randomized to treatment with either simvastatin (40 mg/day) or placebo for 3 weeks before surgery. A group of 15 patients undergoing off-pump coronary surgery served as controls. Blood samples for detection of serum cytokine levels were obtained before anesthesia, at the end of surgery, and at 4, 24, 48, and 72 hours postoperatively. Apoptosis and indices of activation were assessed in cultured neutrophils.

RESULTS

Simvastatin significantly reduced the postoperative peak values of interleukin (IL)-6 and IL-8. The neutrophil apoptotic rate was significantly higher among neutrophils obtained from patients pretreated with simvastatin (p < 0.05 at both 8 and 24 hours) compared with placebo. Neutrophils from the statin group had depressed functional activity, as underscored by significantly lower values of CD11b (p < 0.01 at 24 hours) and a significantly less percentage of cells positive for nitro-blue tetrazolium (p < 0.01 at 12 and 24 hours) compared with placebo.

CONCLUSIONS

This randomized, double-blind study indicates that statin therapy before cardiopulmonary bypass is associated with reduction of circulating markers of inflammation and increased neutrophil apoptosis. These data support a routine inclusion of statins as an adjuvant pharmacologic therapy before cardiopulmonary bypass surgery.

The effect of statin therapy on infection-related mortality in patients with atherosclerotic diseases

OBJECTIVE

Statins have pleiotropic effects that are independent of their lipid-lowering ability. We have previously shown that prior statin therapy is associated with a decreased risk of severe sepsis in patients admitted with acute bacterial infection. The aim of this study was to determine whether statin therapy is associated with a decreased risk of infection-related mortality.

DESIGN

A prospective, observational, population-based study.

SETTING

Tertiary university medical center.

PATIENTS

Using a computerized database, 11,490 patients with atherosclerotic diseases were identified and followed for up to 3 yrs. Two groups of patients were compared: those receiving statins in the final month before follow-up termination and those who were not.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was infection-related mortality. Of the 11,362 patients included in the final analysis, 5,698 (50.1%) belonged to the statin group. Median follow-up was 19.8 months (interquartile range, 14.3-33.3). The risk of infection-related mortality was significantly lower in the statin compared with the no-statin group (0.9% vs. 4.1%), reflecting a relative risk of 0.22 (95% confidence interval, 0.17-0.28). Stepwise Cox proportional hazard survival analysis including a propensity score for receiving statins revealed that the protective effect of statins adjusted for all known potential confounders remained highly significant (hazard ratio, 0.37; 95% confidence interval, 0.27-0.52).

CONCLUSIONS

Therapy with statins may be associated with a reduced risk of infection-related mortality. This protective effect is independent of all known comorbidities and dissipates when the medication is discontinued. If this finding is supported by prospective controlled trials, statins may play an important role in the primary prevention of infection-related mortality.

Non-antiarrhythmic agents for prevention of postoperative atrial fibrillation: role of statins

PURPOSE OF REVIEW

Atrial fibrillation is the most common arrhythmia following cardiac surgery, having both serious medical and socioeconomic consequences. Although there are established antiarrhythmic agents for preventing and treating postoperative atrial fibrillation, these therapies are neither 100% reliable, nor without risks and limitations. Thus, there remains a strong need for non-antiarrhythmic, adjunctive therapies for the prevention of postoperative atrial fibrillation.

RECENT FINDINGS

Long-term statin administration in ambulatory patients is associated with a reduced risk of adverse cardiovascular events, including death, myocardial infarction, stroke, renal dysfunction and atrial fibrillation. Recent evidence suggests, however, that statins may also reduce the risk of acute adverse outcomes following invasive procedures, including postoperative atrial fibrillation. Although the exact mechanisms by which statins may reduce postoperative atrial fibrillation are unclear, accumulating evidence suggests that statins exert multiple effects independent of their effect on LDL cholesterol. For example, in patients with acute coronary syndromes, statin therapy has been shown to modulate remodeling of the cardiac extracellular matrix and to reduce markers of inflammation, including C-reactive protein, serum amyloid A, tumor necrosis factor-alpha, and IL-6.

SUMMARY

Perioperative statin therapy may represent an important non-antiarrhythmic, adjunctive therapeutic strategy for the prevention of postoperative atrial fibrillation.

Randomized Trial of Atorvastatin for Reduction of Postoperative Atrial Fibrillation in Patients Undergoing Cardiac Surgery

Background— Atrial fibrillation (AF) after cardiac surgery is associated with increased risk of complications, length of stay, and cost of care. Observational evidence suggests that patients who have undergone previous statin therapy have a lower incidence of postoperative AF. We tested this observation in a randomized, controlled trial.

Methods and Results— Two hundred patients undergoing elective cardiac surgery with cardiopulmonary bypass, without previous statin treatment or history of AF, were enrolled. Patients were randomized to atorvastatin (40 mg/d, n=101) or placebo (n=99) starting 7 days before operation. The primary end point was incidence of postoperative AF; secondary end points were length of stay, 30-day major adverse cardiac and cerebrovascular events, and postoperative C-reactive protein (CRP) variations. Atorvastatin significantly reduced the incidence of AF versus placebo (35% versus 57%, P =0.003). Accordingly, length of stay was longer in the placebo versus atorvastatin arm (6.9±1.4 versus 6.3±1.2 days, P =0.001). Peak CRP levels were lower in patients without AF ( P =0.01), irrespective of randomization assignment. Multivariable analysis showed that atorvastatin treatment conferred a 61% reduction in risk of AF (odds ratio 0.39, 95% confidence interval 0.18 to 0.85, P =0.017), whereas high postoperative CRP levels were associated with increased risk (odds ratio 2.0, 95% confidence interval 1.2 to 7.0, P =0.01). The incidence of major adverse cardiac and cerebrovascular events at 30 days was similar in the 2 arms.

Conclusions— Treatment with atorvastatin 40 mg/d, initiated 7 days before surgery, significantly reduces the incidence of postoperative AF after elective cardiac surgery with cardiopulmonary bypass and shortens hospital stay. These results may influence practice patterns with regard to adjuvant pharmacological therapy before cardiac surgery.

Preoperative statin therapy is associated with reduced cardiac mortality after coronary artery bypass graft surgery

OBJECTIVE

Statin therapy in ambulatory populations is associated with a significant reduction in adverse cardiovascular events, including death and myocardial infarction. Much less is known about the beneficial effects of statins on acute perioperative cardiovascular events. The purpose of this study was to determine whether preoperative statin therapy is associated with a reduced risk of early cardiac death or nonfatal, in-hospital postoperative myocardial infarction after primary, elective coronary artery bypass graft surgery requiring cardiopulmonary bypass.

METHODS

The Multicenter Study of Perioperative Ischemia (McSPI) Epidemiology II Study was a prospective, longitudinal study of 5436 patients undergoing coronary artery bypass graft surgery between November 1996 and June 2000 at 70 centers in 17 countries. The present study consisted of a pre-specified subset of these subjects divided into patients receiving (n = 1352) and not receiving (n = 1314) preoperative statin therapy. To control for potential bias related to use of statin therapy, the study estimated propensity scores by logistic regression to determine the predicted probability of inclusion in the "statin" group. Multivariate, stepwise logistic regression was then performed, controlling for patient demographics, medical history, operative characteristics, and propensity score to determine whether preoperative statin therapy was independently associated with a reduction in the risk of early (DOS-POD3) cardiac death and/or nonfatal, in-hospital postoperative myocardial infarction.

RESULTS

Preoperative statin therapy was independently associated with a significant reduction (adjusted odds ratio [OR] 0.25; 95% confidence intervals [CI] 0.07-0.87) in the risk of early cardiac death after primary, elective coronary bypass surgery (0.3% vs 1.4%; P < .03), but was not associated with a reduced risk of postoperative nonfatal, in-hospital myocardial infarction (7.9% vs 6.2%; P = not significant). Discontinuation of statin therapy after surgery was independently associated with a significant increase in late (POD4-discharge) all-cause mortality (adjusted OR 2.64; 95% CI 1.32-5.26) compared with continuation of statin therapy (2.64% vs 0.60%; P < .01). This was true even when controlling for the postoperative discontinuation of aspirin, beta-blocker, or angiotensin-converting enzyme inhibitor therapy. Discontinuation of statin therapy after surgery was also independently associated with a significant increase in late cardiac mortality (adjusted OR 2.95; 95% CI 1.31-6.66) compared with continuation of statin therapy (1.91% vs 0.45%; P < 0.01).

CONCLUSIONS

Preoperative statin use is associated with reduced cardiac mortality after primary, elective coronary artery bypass grafting. Postoperative statin discontinuation is associated with increased in-hospital mortality. Although further randomized trials are needed to confirm these findings, these data suggest the importance of perioperative statin administration.