The Predictive Role of Inflammatory Biomarkers in Atrial Fibrillation as Seen through Neutrophil-Lymphocyte Ratio Mirror

Table 2

Clinical studies on the predictive value of the neutrophil-lymphocyte ratio as a biomarker in atrial fibrillation.

Study [ref]	Year	Number of patients	Threshold	Assessment period	Results
Gibson et al. [21]	2010	275 patients without previous atrial arrhythmia, undergoing CABG	Median comparison between groups	Preoperatively and on postoperative day 2	The incidence of AF was greater in groups with higher preoperative NLR (median 3.0 versus 2.4, ) and postoperative NLR (median 9.2 versus 7.2, )
Ertaş et al. [20]	2013	126 patients with nonvalvular AF	Mean comparison among subjects with or without stroke	At admission	In patients with nonvalvular AF, mean NLR was significantly higher among subjects with stroke compared to individuals without a stroke (5.6 versus 3.1)
Canpolat et al. [65]	2013	251 patients with symptomatic AF who underwent cryoablation	3.15	Preprocedural	Patients with a high preablation NLR (>3.15) had a 2.5-fold increased risk of AF recurrence after successful cryoablation
Im et al. [68]	2013	499 patients who underwent RFCA for paroxysmal or persistent AF	5.6	At baseline and on day 1 after RFCA	In multivariate analysis, a high post-NLR was an independent predictor for early recurrence after RFCA (HR 1.09; 0.047). Patients with higher NLR (>5.6) had significantly lower AF-free survival on Kaplan-Meier (K-M) curve
Sahin et al. [60]	2013	144 diabetic patients (72 with and 72 without AF)	2.38 (analysis included mean comparison between groups)	Retrospectively recorded from patient files	The mean NLR was significantly higher in diabetic patients with AF than in those without (mean 2.87 versus 2.2, ). Using a cut-off point of 2.38 NLR was associated with AF (OR 3.486, )
Trivedi et al. [70]	2013	165 patients with paroxysmal AF, who underwent RFCA	3.08 (analysis included mean comparison between groups)	One day prior to ablation	Baseline NLR was high in patients with AF recurrence (mean 3.2 versus 2.5, ). A high baseline NLR (>3.08) was a significant predictor of postablation AF recurrence (HR 1.99, 95% CI 1.33–2.96, )
Guo et al. [69]	2014	379 lone AF patients who underwent catheter ablation	5.15 (analysis included mean comparison between groups)	Before and after catheter ablation	The patients who developed AF recurrence had a higher postablation NLR than patients with no recurrence (5.74 versus 4.66, ). A high postablation NLR (>5.15) was an independent predictor of AF recurrence (HR 1.514, 95% CI 1.36–1.68, )
Acet et al. [71]	2014	A total of 197 subjects (71 with paroxysmal, 63 with persistent/permanent AF, and 63 AF-free controls)	2.1 (analysis included mean comparison between groups)	At baseline	Higher NLR (>2.1) had a significant relationship with nonvalvular AF (OR 11.31, ) compared with control group; and the mean value was significantly higher in those with persistent/permanent compared to those with paroxysmal AF (3.4 ± 0.6, versus 2.5 ± 0.6, )
Nikoo et al. [26]	2014	112 AF patients and 107 controls	Mean comparison between groups	At baseline	A significant positive correlation was observed between NLR and increased interleukin-17 (IL-17A) in AF (). Elevated IL-17A, on the other hand, was significantly increased in patients with AF compared to controls (1.28 ± 3.5 versus 0.19 ± 0.64 pg/mL, )
Karavelioğlu et al. [64]	2015	218 patients restored to sinus rhythm with amiodarone	Mean comparison between groups	At admission	A high NLR was an independent predictor of AF recurrence (OR 1.584 [1.197–2.095], ) after successful cardioversion with amiodarone
Yalcin et al. [61]	2015	309 patients with nonvalvular AF who underwent TEE	2.59	Before TEE	A high NLR (>2.59) was an independent risk factor for the presence of left atrial thrombus on TEE (OR 1.59; ) in patients with nonvalvular AF
Saliba et al. [62]	2015	32.912 patients with AF	Multiple cut-offs in quartiles	Median NLR value of the tests performed in the year prior to study entry	Each increase in NLR quartile above the lowest was associated with a significant increase in the risk of stroke with HRs (95% CI) 1.11 (0.91–1.35), 1.25 (1.03–1.51), and 1.56 (1.29–1.88) for the second, third, and highest quartiles, respectively
Chavarria et al. [59]	2015	290 patients who underwent PCI for acute STEMI	Median comparison between groups	<6 hours preprocedural, <12, 48, and 96 hours postprocedural	Patients who developed AF (, 13.8%) had higher postcatheterization NLR at 48 hours (median 5.23 versus 3.00, ) and 96 hours (median 4.67 versus 3.56, )
Fukuda et al. [63]	2015	120 patients with paroxysmal AF	2.92	At baseline	A higher NLR (>2.92) was a predictor of reduced LAAWV in patients with paroxysmal AF
Wagdy et al. [72]	2016	200 patients with STEMI	4.6	At admission	A higher NLR (>4.6) was an independent predictor of NOAF, no-reflow, and in-hospital MACE (OR 3.5, ) in patients with STEMI, after adjustment for confounding factors

AF: atrial fibrillation; NLR: neutrophil-lymphocyte ratio; OR: Odds Ratio; TEE: transesophageal echocardiography; CABG: coronary artery bypass grafting; RFCA: radiofrequency catheter ablation; NOAF: new-onset atrial fibrillation; LAAWV: left atrial appendage wall velocity; NA: not available; STEMI: ST-segment elevation myocardial infarction; CI: confidence interval; IL-17A: interleukin-17A; MACE: major adverse cardiovascular events; PCI: percutaneous coronary intervention.