Statins Reduce Amputations After Lower Extremity Procedures

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Preoperative statins are associated with improved limb salvage after lower extremity revascularization, either endovascular or surgical. Patients who benefit most seem to be those with claudication, according to a large Medicare population study appearing online December 3, 2013, ahead of print in Circulation: Cardiovascular Interventions.

Researchers led by Todd R. Vogel, MD, MPH, of the University of Missouri School of Medicine (Columbia, MO), looked at 22,954 Medicare patients who were hospitalized for lower extremity revascularization during 2007 to 2008. Over half (62.5%) received endovascular revascularization, while the remainder underwent surgery. Patients were hospitalized for conditions including:

• Claudication (n=8,128)
• Rest Pain (n=3,056)
• Ulceration/gangrene (n=11,770)

Half of Patients on Statins

Slightly more than half of the entire cohort (n=11,687, 50.9%) were identified as statin users (for  at least 3 months prior to revascularization; drugs included lovastatin, rosuvastatin, fluvastatin, atorvastatin, pitavastatin,  pravastatin, or simvastatin). The use of statins differed by disease severity. Patients with claudication used statins before surgery more frequently (59.3%) than patients with rest pain (48.9%) or ulceration/gangrene (45.1%; P < 0.0001).

Patients who used statins were less likely than those who did not use the drugs to have an amputation within 30 days (RR 0.80; 95% CI 0.75-0.86), 90 days (RR 0.80; 95% CI 0.76-0.85) and 1 year (RR 0.82; 95% CI 0.78-0.86; all P < 0.0001) of revascularization.  The benefits of statin use were similar regardless of whether patients underwent endovascular or surgical revascularization (table 1).

Table 1. Unadjusted Amputation Risk in Statin vs. Non-statin Users

For patients with claudication, lack of statin use prior to surgery was associated with an elevated risk of amputation (HR 1.55; 95% CI 1.16-2.06; P = 0.003), whereas the association just missed statistical significance for patients with rest pain (HR 1.26; 95% CI 0.99-1.62; P = 0.06). Among patients with ulceration/gangrene, there seemed to be no association between previous statin use and amputation (P = 0.65). For patients with claudication, open surgery was also associated with a higher risk of amputation (HR 1.94; 95% CI 1.45-2.60).

‘Severe Underuse’ of Statins Cited

“This longitudinal analysis of the US Medicare population has demonstrated that preoperative statin use was significantly associated with improved 1-year limb salvage in patients undergoing either open or endovascular [lower extremity] revascularization,” the authors conclude.

An unexpected finding, they add, was that only half of the Medicare population with atherosclerosis undergoing lower extremity revascularization was on preoperative statins.  “Our study suggests severe underuse of statin therapy in a population where there is sufficient evidence to suggest that compliance with therapy improves outcomes,” the investigators say.

Dr. Vogel and colleagues add that the mechanism by which statins exert their protective effect remains unclear, although  some authors have suggested that lower plasma LDL cholesterol concentrations among patients on statins may allow plaques to be less occlusive and less likely to rupture and cause thrombosis. “Therefore, it has been hypothesized that statins may slow the progression of atherosclerosis, and others have suggested that the addition of lipid-lowering treatment may improve local symptoms and reduce the need for reconstructive surgery,” they observe.

In an email communication with TCTMD, Gennaro Sardella, MD, of “Sapienza” University of Rome (Rome, Italy), commented that the results of the paper “are expected, in my opinion, according to the beneficial effects of statins in patients undergoing coronary revascularization.”

He attributed the benefits seen with statins to pleiotropic effects “beyond the cholesterol level lowering, in terms of endothelial function improving, enhancing the stability of atherosclerotic plaque and inhibiting the thrombogenic response.”

Dr. Sardella noted that claudication patients most likely benefit in particular because they are at high risk, as well as ACS patients.“Evidence based medicine suggests a preventive high loading statin dose in all atherosclerotic patients undergoing revascularization,” he said. “[Nevertheless], statin therapy is underused as preload therapy in coronary and peripheral intervention.”

 

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Source:
Vogel TR, Dombrovskiy VY, Galiñanes EL, et al. Preoperative statins and limb salvage after lower extremity revascularization in the Medicare population. Circ Cardiovasc Interv. 2013;Epub ahead of print.

 

Disclosures:

• The study was supported in part by the American Heart Association.
• Drs. Vogel and Sardella report no relevant conflicts of interest.

 

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