Prehospital HMG Co-A Reductase Inhibitor Use and Reduced Mortality in Ruptured Abdominal Aortic Aneurysm

Dyslipidemia Part 2: Review of Dyslipidemia Treatment in Patients With Noncoronary Vascular Disease

Dyslipidemia is one of the major modifiable risk factors associated with atherosclerotic cardiovascular disease. Appropriate modification of lipid profiles reduces the progression of atherosclerosis in vessel walls across all vascular beds. The management of dyslipidemia has evolved over the last several decades, especially since the discovery of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, also known as statins. Statin use in atherosclerotic heart disease is well described in observational and prospective placebo-controlled studies, citing both lipid-lowering and pleiotropic effects. However, the effect of statins and other lipid-lowering agents on noncoronary arterial beds (the aorta, arteries to the extremities, renal, and carotid arteries) is less understood. This article is part 2 of a 2-part review, with part 1 having focused on lipid metabolism and the downstream effects of lipids on the development of atherosclerosis. The current review (part 2) will discuss trials, retrospective reviews, and observational cohort studies regarding the use of statins and/or other lipid-lowering drugs for primary and secondary prevention of peripheral noncoronary atherosclerotic disease.

Distinct impact of three different statins on arteriovenous fistula outcomes: a retrospective analysis

PURPOSE

Whether statins improve arteriovenous fistula (AVF) outcomes is still a matter of debate. Taking into consideration the existing physicochemical differences between individual drugs, this study evaluates the impact of three different statins (atorvastatin, rosuvastatin and simvastatin) on one-stage and two-stage AVF outcomes.

METHODS

Using a retrospective cohort of 535 patients, we analyzed the effects of each statin on primary failure and primary patency using multivariate logistic regressions and Cox proportional hazard models.

RESULTS

Out of the three statins analyzed, only atorvastatin improved the overall primary failure of AVF (odds ratio [OR] = 0.18, p = 0.005). Comparisons between the two AVF types demonstrated that this effect was due to a prominent reduction in primary failure of one-stage (OR = 0.03; p = 0.005), but not two-stage fistulas (OR = 0.43; p = 0.25). In contrast, primary patency of two-stage (hazards ratio [HR] = 0.51; p = 0.024), but not one-stage fistulas (HR = 0.98; p = 0.95), was improved by all statins as a group, but not by individual drugs.

CONCLUSIONS

Our results suggest that the potential benefit of statins on AVF outcomes is a drug-specific and not a class effect, and that such effect is also influenced by the type of fistula.

Statin use and rupture of abdominal aortic aneurysm

BACKGROUND

Ruptured abdominal aortic aneurysm (rAAA) is associated with high mortality. Research suggests that statins may reduce abdominal aortic aneurysm (AAA) growth and improve rAAA outcomes. However, the clinical impact of statins remains uncertain in relation to both the risk and prognosis of rAAA.

METHODS

This nationwide, population-based, combined case-control and follow-up study included all patients (aged at least 50 years) with a first-time hospital admission for rAAA and 1:1 matched AAA controls without rupture in Denmark from 1996 to 2008. Individual-level data on preadmission drug use, co-morbidities, socioeconomic markers, healthcare contacts and death were obtained from Danish nationwide registries.

RESULTS

The study included 3584 cases and 3584 matched controls. Current statin use was registered for 418 patients with rAAA (11.7 per cent) and 539 AAA controls (15.0 per cent), corresponding to an age- and sex-matched odds ratio (OR) of 0.70 (95 per cent confidence interval (c.i.) 0.60 to 0.81) for rAAA in current statin users versus never users. The decreased risk of rAAA remained after adjustment for potential confounding factors (adjusted OR 0.73, 0.61 to 0.86). The overall 30-day mortality rate from time of hospital admission among patients with rAAA was 46.1 per cent in current statin users compared with 59.3 per cent in never users (adjusted mortality rate ratio (MRR) 0.80, 95 per cent c.i. 0.68 to 0.95). Patients who had formerly used statins did not have reduced mortality (adjusted MRR 0.98, 0.78 to 1.22).

CONCLUSION

Statin use was associated with a reduced risk of rAAA and lower case fatality following rAAA. These results support current guidelines that recommend statin therapy in patients diagnosed with AAA.

Combination therapy with atorvastatin and amlodipine suppresses angiotensin II-induced aortic aneurysm formation

Background

Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease. It is controversial whether statin and calcium channel blockers (CCBs) has an inhibitory effect on the expansion of AAA. Some studies reported that CCBs have an inhibitory effect on Rho-kinase activity. Rho-kinase plays an important role in the pathogenesis of various cardiovascular diseases. However, there is no study reporting of the association between Rho-kinase and human AAAs.

Methods and Results

Experimental AAA was induced in Apolipoprotein E-deficient (ApoE^-/-) mice infused with angiotensin II (AngII) for 28 days. They were randomly divided into the following 5 groups; saline infusion alone (sham), AngII infusion alone, AngII infusion plus atorvastatin (10 mg/kg/day), AngII infusion plus amlodipine (1 mg/kg/day), and AngII infusion plus combination therapy with atorvastatin (10 mg/kg/day) and amlodipine (1 mg/kg/day). The combination therapy significantly suppressed AngII-induced increase in maximal aortic diameter as compared with sham, whereas each monotherapy had no inhibitory effects. The combination therapy significantly reduced AngII-induced apoptosis and elastin degradation at the AAA lesion, whereas each monotherapy did not. Moreover, Rho-kinase activity, as evaluated by the extent of phosphorylation of myosin-binding subunit (a substrate of Rho-kinase) and matrix metalloproteinase activity were significantly increased in the AngII-induced AAA lesion as compared with sham, both of which were again significantly suppressed by the combination therapy. In human aortic samples, immunohistochemistory revealed that the activity and expression of Rho-kinase was up-regulated in AAA lesion as compared with abdominal aorta from control subjects.

Conclusions

Rho-kinase is up-regulated in the aortic wall of human AAA. The combination therapy with amlodipine and Atorvastatin, but not each monotherapy, suppresses AngII-induced AAA formation in mice in vivo, for which Rho-kinase inhibition may be involved.

Current status of medical management for abdominal aortic aneurysm

Previous trials indicate that surgical management of small abdominal aortic aneurysms (AAA) does not reduce mortality. The medical management of AAA, however, has to a large degree been ignored until recently. Medical management is not only needed to limit the expansion of small AAAs but also to reduce the high incidence of other cardiovascular events in these patients. In this review current evidence regarding medical therapy for patients with small AAAs is discussed. Four current randomised controlled trials are examining the efficacy of exercise, doxycycline and angiotensin converting enzyme inhibition in limiting AAA progression. A further trial using a mast cell stabilisation agent is expected to start soon. It is anticipated that a range of novel therapies for small AAAs will be identified within the next decade.

Systematic review and meta-analysis of the effects of statin therapy on abdominal aortic aneurysms

Background

The aim was to investigate the effects of statin therapy on abdominal aortic aneurysm (AAA) disease.

Methods

PubMed, the Cochrane Library, Embase and ClinicalTrials.gov were searched for all studies on any clinical effect of statin therapy on AAA. Outcomes were selected based on their inclusion in two or more studies: AAA expansion rate, 30-day mortality, and short- and long-term postoperative mortality. The data were subjected to meta-analysis by outcome.

Results

Twelve cohort studies were selected for inclusion involving 11 933 individuals. Meta-analysis of four studies examining all-cause postoperative mortality showed a significant improvement with statin therapy at 1, 2 and 5 years (odds ratio (OR) at 5 years 0·57, 95 per cent confidence interval (c.i.) 0·42 to 0·79; P < 0·001) with minimal heterogeneity between the four included studies. There was no significant difference in 30-day mortality after AAA treatment in patients on statin therapy (OR 0·22, 0·02 to 2·90; P = 0·25). Sensitivity analysis including four high-quality studies examining AAA expansion rates showed no significant difference with statin therapy: standardized mean difference −0·14 (95 per cent c.i. −0·33 to −0·05) mm/year (P = 0·16).

Conclusion

The claim of a reduction in AAA expansion rate with statin therapy is based on low-quality evidence and was not significant on meta-analysis. However, statin therapy did appear to improve all-cause survival after AAA repair.

Basic Science Review Section: Statin Therapy—Part II: Clinical Considerations for Cardiovascular Disease

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, commonly known as statins, are the medical treatment of choice for hypercholesterolemia. In addition to achieving a therapeutic decrease in serum cholesterol levels, statin therapy appears to promote pleiotropic effects that are independent of changes in serum cholesterol. These cholesterol lowering and pleiotropic effects are beneficial not only for the coronary circulation, but for the myocardium and peripheral arterial system as well. Patients receiving statin therapy must be carefully monitored, however, as statins potentially have harmful side effects and drug interactions. This article is part II of a 2-part review, and it focuses on the clinical aspects of statin therapy in cardiovascular disease.