Role of Neutrophil-Lymphocyte Ratio and Mean Platelet Volume in the Outcome of Atherosclerotic Peripheral Vascular Disease Interventions
Authors: Balaji SK , Robinson C Saravanan , Yalamuru Sudharsan Reddy , Kumar Sabarish G , Maruthupandian Adharsh Kumar , Ahmed Syed Mohammed Ali , Bharat Arun MV , Ray Ruru 
Published: August 2022

Purpose:
Classically, neutrophils have been neglected in the pathophysiology of atherosclerosis. However, recent studies have highlighted their role. Similarly, the role of platelets in peripheral artery disease (PAD) has become evident now. The significance of neutrophil-lymphocyte ratio (NLR) and mean platelet volume (MPV) has been independently studied and found that elevated values are associated with poor outcomes of atherosclerotic peripheral vascular disease interventions. However, the measure of association of NLR and MPV to the outcomes of intervention has not been studied. Hence, this study was undertaken to examine the measure of association of NLR and MPV to the outcomes of atherosclerotic peripheral vascular disease interventions.

Methodology:
This is a prospective study conducted between January 1, 2020, and September 30, 2021, with 6 months of follow-up. Patients aged 21 years or more, diagnosed to have atherosclerotic peripheral vascular disease, and undergoing interventions (endovascular and open procedure) are included in the study. Patients <21 years, not willing for any intervention, and with acute presentations were excluded. The primary endpoint assessed is graft patency at 6 months, and the secondary endpoints assessed are clinical improvement (which is a combined measure of change in ankle–brachial index, Rutherford grade, and ulcer status) at 1 and 6 months, redo procedure, and amputations within the follow-up period.

Results:
From January 2020 to September 2021, a total of 156 patients with atherosclerotic peripheral vascular disease fulfilled the inclusion and exclusion criteria. We observed that in 109 (69.9%) patients who had completed 6-month follow-up, 91 (83.5%) patients had graft patency and 18 (16.5%) patients had occluded graft. Independent receiver operating characteristic curve analysis of MPV and NLR showed that lower mean NLR and MPV values (cutoff taken as 10.15 for MPV) are associated with increased graft patency at 6 months than higher mean NLR and MPV values (NLR, P < 0.001; MPV, P = 0.024). Discriminant analysis model developed with MPV and NLR as the set of predictors showed that NLR and MPV together are good predictors of graft patency at 6 months (Wilk's lambda: χ2 = 45.54, P < 0.001). However, logistic regression analysis has shown that, in comparison to NLR, MPV is not a strong predictor of graft patency. Lower mean NLR value was associated with lower amputation rate (P < 0.001), lower mortality rate (P < 0.001), and higher clinical improvement rate at 1st month (P < 0.001) and at 6 months (P < 0.001) than patients with higher mean NLR. However, there was no statistically significant difference between two groups in predicting chance of redo procedure (P = 0.424). There was no statistically significant difference between the mean MPV values among patients who underwent amputation (P = 0.864), died (P = 0.640), or had redo procedure (P = 0.883), except for clinical improvement outcome where lower mean MPV value was associated with higher rate of clinical improvement at 1st month (P < 0.001) and 6 months (P < 0.001) than higher mean MPV value.

Conclusion:
In patients with atherosclerotic peripheral vascular disease, NLR value is a better predictor of outcomes after intervention than MPV, and lower mean NLR values are associated with increased rate of graft patency, clinical improvement, fewer amputations, and deaths.