Elevated Neutrophil to Lymphocyte Ratio Portends a Higher Risk of Amputation After Lower Extremity Atherectomy for Peripheral Arterial Disease

Abstract

Elevated neutrophil to lymphocyte ratio (NLR) is a known prognosticator of adverse events after several vascular procedures such as endovascular aortic repair and lower extremity stenting, but the impact of NLR on atherectomy outcomes is unknown. We set out to compare immediate and long-term outcomes after atherectomy based on patient NLR. We analyzed atherectomy procedures performed in femoropopliteal and tibial vessels on 212 patients from January 2014 to September 2019 with a median NLR of 3.0. The patients were subsequently placed into two cohorts: those equal to or above the median NLR (NLR ≥ 3) and those below the median NLR (NLR < 3). Reintervention was defined as any arterial operation to the same location as the index operation in the lower extremity. Kaplan-Meier (KM) survival analyses were performed to compare reintervention-free and amputation-free survival in the two cohorts. Multivariate logistic regression analyses were performed to determine the adjusted odds ratios of reintervention and amputation based on NLR. A total of 108 patients had NLR< 3 and 104 NLR ≥ 3. The NLR ≥ 3 cohort had a higher rate of end-stage renal disease (21.4% vs 3.7%, P < .001) and diabetes mellitus (77.9% vs 64.5%, P = .046), whereas other measured demographics and comorbidities were not significantly different. Indication for atherectomy differed between NLR < 3 vs NLR ≥ 3: claudication (46% vs 28%), chronic limb threatening ischemia (44% vs 64%), and acute limb ischemia (11% vs 8%), P = .003. The atherectomy region also differed between NLR< 3 vs NLR ≥ 3 cohorts: femoropopliteal (74% vs 55%) and tibial (26% vs 45%), P = .004. The adjusted analyses controlled for these differences. The KM log-rank test revealed no difference in reintervention-free survival between the two cohorts (P = .19). Multivariate logistic regression also revealed no significant difference in odds of reintervention between the cohorts (odds ratio: 1.58 [95% confidence interval: 0.80-3.14], P = .186). The KM log-rank test revealed a difference in amputation free-survival between the cohorts (P = .019) throughout the first four postoperative years (Table). On multivariate analysis, the NLR ≥ 3 cohort was at higher adjusted risk for amputation (odds ratio: 6.33 [95% confidence interval: 1.08-70.50], P = .028). High preoperative inflammatory activity determined by higher NLR in patients who underwent lower extremity atherectomy for peripheral artery disease was associated with different comorbidities, more severe disease, poorer same-side amputation-free survival, and higher odds of amputation on adjusted analysis. NLR did not impact reintervention after the index procedure. Further investigation with larger studies may help us understand more the role of inflammation in the management of peripheral artery disease.TableOutcomes of clinical failure, reintervention, and same-side amputationLogistic regression odds ratios NLR ≥ 3 vs NLR < 3OutcomeUnivariate OR (95% CI)P valueMultivariate OR (95% CI)P valueReintervention1.16 (0.63-2.15).6261.38 (0.67-2.85).387Same-side amputation4.26 (1.28-19.24).0306.33 (1.08-70.05).028CI, Confidence interval; NLR, neutrophil to lymphocyte ratio; OR, odds ratio. Open table in a new tab Tabled 1Kaplan-Meier curvesReintervention-free survivalAmputation-free survival Open table in a new tab