NLR, PLR ratios affect left ventricular thrombosis resolution after AMI

High neutrophil-to-lymphocyte (NLR) and platelet-to-lymphocyte (PLR) ratios may be indicative of a failure to resolve left ventricular thrombosis (LVT) in postacute myocardial infarction (post-AMI) patients not receiving percutaneous coronary intervention (PCI), according to a new Singapore study.

“Post-AMI patients not receiving PCI complicated by LVT may have a greater inflammatory response reflected by a higher NLR and PLR. Consequently, these patients experience less LVT resolution despite anticoagulation,” researchers said.

Of the 289 enrolled patients (mean age, 59.3±13.4 years; 251 males), 172 saw the resolution of LVT, while failure was reported in 60. There were 24 recorded in-hospital deaths, resulting in a rate of 8.3 percent, and 33 participants (11.4 percent) were lost to follow-up. The cohort was followed for a median for 1.9 years, and LVT was diagnosed after a median of 3 days from index AMI. [Thromb Res 2020;194:16-20]

Admission PLR was significantly higher in those with unresolved LVT (153.6±88.0 vs 124.7±69.1; p=0.028), while the estimated glomerular filtration rate was lower (66.5±26.5 vs 82.1±21.3; p=0.002). There was likewise a between-group discrepancy in NLR at admission that trended toward significance (6.3±4.5 vs 4.9±4.3; p=0.064).

In terms of outcomes, there was a significant excess of all-cause mortality in patient with unresolved LVT (59.3 percent vs 19.2 percent; p<0.001). No such effect was found for bleeding (p=0.169) or stroke (p=0.695).

Multivariate binomial logistic regression analysis revealed that each unit increase in NLR reduced the likelihood of LVT resolution by almost 20 percent (odds ratio [OR], 0.818, 95 percent confidence interval [CI], 0.674–0.994). This model also showed that PCI was a positive predictor of successful resolution (OR, 3.172, 95 percent CI, 1.355–7.427; p=0.008).

In a separate model for PLR, each 10-unit increment significantly reduced the odds of LVT by more than 10 percent (OR, 0.893, 95 percent CI, 0.808–0.986; p=0.026). PCI again emerged as a significant positive correlate of LVT resolution in this model (OR, 2.921, 95 percent CI, 1.268–6.727; p=0.012).

In terms of outcome, both high NLR (OR per unit, 1.164, 95 percent CI, 1.007–1.344; p=0.039) and PLR (OR per 10 units, 1.081, 95 percent CI, 1.002–1.164; p=0.043) were significantly associated with all-cause mortality in participants who did not undergo PCI. These interactions were attenuated after multivariable adjustments.

“To the best of our knowledge, this is the first study that evaluated predictors of thrombus resolution in a cohort with a substantial number of post-AMI patients complicated by LVT,” the researchers said.

“Higher NLR [and] PLR are independent predictors of LVT resolution failure, but only amongst patients that did not undergo PCI. This may be that in patients that did not receive PCI, there is greater ischaemia leading to a greater overall inflammatory response,” they added, pointing out that high NLR and PLR might prolong a pro-inflammatory state, which would lead to poorer thrombus resolution.

“Both NLR and PLR may identify a subset of patients with LVT requiring longer-term anticoagulation,” they said. “Further studies are required to study this association.”