C-reactive protein and brain natriuretic peptide as predictors of adverse events after lower extremity endovascular revascularization.

BACKGROUND: High-sensitivity C-reactive protein (hsCRP) and brain natriuretic peptide (BNP) have been shown to be independent predictors of adverse cardiovascular outcomes and increased risk of secondary interventions or limb loss in patients with peripheral arterial disease (PAD). To assist clinicians in decision-making about treatment approaches and predicting postprocedure mortality and morbidity, we retrospectively examined patients with preprocedure hsCRP and BNP levels who underwent elective angioplasty or stent placement for lower extremity PAD.

METHODS: The study period was from January 1, 2007, to December 31, 2012, and patients were included who had angioplasty or stenting for PAD. Minimal required follow-up for study inclusion was at least one postoperative ankle-brachial index, contrast angiography, or duplex imaging of the treated limb. Events of interest included major adverse limb events (MALE), defined as target vessel revascularization, amputation, or disease progression by 1 year, and major adverse cardiovascular events (MACE; stroke, myocardial infarction, or death) by 2 years. Elevated/abnormal values for our biomarkers of interest were established by the upper limits of our institution's clinical laboratory reference range (hsCRP, >0.80 mg/dL; BNP, >100 pg/mL).

RESULTS: A total of 159 limbs in 118 patients were included in analysis (42% men; median age [range], 64 [42-87] years). All limbs were symptomatic (Rutherford classification: 1-6). Iliac artery revascularization without other adjunct lower extremity intervention was performed in 60% of the limbs. High hsCRP levels (>0.80 mg/dL) were present in 32 patients (27%) and high BNP values (>100 pg/mL) in 24 patients (20%). Kaplan-Meier analysis with log-rank comparison demonstrated that elevated hsCRP levels were associated with MALE but only in limbs receiving interventions distal to the iliac arteries (P = .005). High BNP levels did not affect MALE rates (P = .821). Conversely, both elevated BNP levels (hazard ratio, 5.6; 95% confidence interval [CI], 2.0-5.8; P = .001) and hsCRP levels (hazard ratio, 2.9; 95% CI, 1.1-7.6; P = .034) predicted MACE at 2 years in the presence of confounders in Cox proportional hazards multivariate analysis. Patients with high preintervention values of hsCRP and BNP were 10.6 times (95% CI, 2.6-42.9; P = .001) more likely to experience MACE than were patients with normal hsCRP and BNP values.

CONCLUSIONS: After lower extremity endovascular interventions, elevated preprocedural hsCRP levels are associated with MALE (femoral-popliteal interventions), and elevated levels of hsCRP and BNP are associated with late cardiovascular events.