Diffferential effects of LDL Lowering on CMR measures of calf muscle perfusion and cellular metabolism in peripheral arterial disease

Abstract

Methods 36 patients with mild-to-moderate symptomatic PAD (mean age 63 ± 11 years, ankle brachial index (ABI) 0.70 ± 0.14) were studied for two years after beginning lipidlowering therapy. Statin-naive patients were treated with simvastatin 40 mg or simvastatin 40 mg plus ezetimibe 10 mg and patients previously on a statin had ezetimbibe 10 mg added (total n = 36). Phosphocreatine recovery time constant (PCr) was measured using 31P MRS at 1.5 T after symptom-limited calf muscle exercise. PCr was calculated using a monoexponential fit of phosphocreatine concentration versus time, beginning at peak exercise. Calf muscle perfusion (n = 28, excluding those with compromised renal function) was measured at 1.5 T with gadolinium (0.1 mM/kg) infused after patients used a pedal ergometer to exhaustion (Figure 1). Slope of the time intensity curve in the calf muscle region with the greatest signal intensity defined tissue perfusion and was divided by the arterial input slope to define perfusion index. Gadolinium enhanced MRA from the distal aorta to the foot was graded for location and degree of stenosis (MRA Index). Skinner-Gardner treadmill test with post-exercise ABI and 6 minute supervised walks were performed. Changes in parameters over time were compared by ANOVA. from 13th Annual SCMR Scientific Sessions Phoenix, AZ, USA. 21-24 January 2010