C-Reactive Protein and Brain Natriuretic Peptide as Predictors of Adverse Events Following Lower Extremity Endovascular Revascularization

Abstract

High sensitivity-C-reactive protein (CRP) and brain natriuretic peptide (BNP) have been shown to be independent predictors of adverse cardiovascular outcomes and potentially increased risk of secondary interventions or limb loss in patients with peripheral arterial disease (PAD). To assist clinicians in predicting postprocedure mortality and morbidity and decision-making regarding treatment approaches, we retrospectively examined patients with preprocedure CRP and BNP levels who underwent elective angioplasty and/or stent placement for lower extremity PAD. The study period included patients treated between 2007 and 2012. Minimal required follow-up was at least one postoperative ankle brachial index or duplex imaging of the treated limb. Events of interest included clinical limb failure (loss of patency, target vessel revascularization, decrease in ankle brachial index >0.15 or limb amputation) by 1 year and MACE (stroke, myocardial infarction or death) by 2 years. Elevated/ abnormal values for our biomarkers of interest were established by the upper limited of our institution's clinical laboratory reference range hs-CRP (<0.80 mg/dL), BNP (<100 pg/mL). A total of 159 limbs in 118 patients were included in analysis (42% male, mean age 64 ± 11 years). All limbs were symptomatic (Rutherford classification, 2-5). Iliac artery revascularization without other adjunct lower extremity intervention was performed in 60% of the limbs. High CRP levels (>0.80 mg/dL) were present in 32 (27%) patients and high BNP values (>100 pg/mL) in 24 (20%) patients. Kaplan-Meier analysis with log-rank comparison demonstrated that elevated CRP levels associated with clinical limb failure but only in limbs receiving interventions distal to the external iliac artery (P < .01). High BNP levels did not affect limb failure (0.91). Conversely, high BNP levels associated with a statistically elevated MACE rate at 2 years of 36% vs 14% in patients with normal BNP levels (P = .01). Patients with high CRP trended toward having higher rates of MACE (33% vs 14%) but failed to meet statistical significance (P = .053). Patients with high preintervention values of CRP and BNP were 10.6 times (95% confidence interval, 2.6-42.6; P < .01) more likely to experience MACE than patients with normal CRP and BNP values. Preprocedure biochemical markers in endovascular interventions for PAD can aide in predicting future limb related complications and late cardiovascular events. Potentially, improving biochemical markers prior to intervention could improve outcomes.