Value of the Neutrophil to Lymphocyte Ratio and Platelet to Lymphocyte Ratio in Predicting CPET Performance in Patients with Stable CAD and Recent Elective PCI

Abstract

Background and Objectives: Functional capacity (FC) assessed via cardiopulmonary exercise testing (CPET) is a novel, independent prognostic marker for patients with coronary artery disease (CAD). Neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) are two readily available predictors of systemic inflammation and cardiovascular event risk, which could be used as cost-effective predictors of poor FC. The purpose of this study was to evaluate the utility of NLR and PLR in predicting poor FC in patients with CAD and recent elective percutaneous coronary intervention (PCI). Materials and Methods: Our cross-sectional retrospective analysis included 80 patients with stable CAD and recent elective PCI (mean age 55.51 ± 11.83 years, 71.3% male) who were referred to a cardiovascular rehabilitation center from January 2020 to June 2021. All patients underwent clinical examination, cardiopulmonary exercise testing on a cycle ergometer, transthoracic echocardiography and standard blood analysis. Results: Patients were classified according to percent predicted oxygen uptake (% VO2 max) in two groups—poor FC (≤70%, n = 35) and preserved FC (>70%, n = 45). There was no significant difference between groups regarding age, gender ratio, presence of associated comorbidities, left ventricular ejection fraction and NLR. PLR was higher in patients with poor FC (169.8 ± 59.3 vs. 137.4 ± 35.9, p = 0.003). A PLR cut-off point of 139 had 74% sensitivity and 60% specificity in predicting poor FC. After multivariate analysis, PLR remained a significant predictor of poor functional status. Conclusions: Although CPET is the gold standard test for assessing FC prior to cardiovascular rehabilitation, its availability remains limited. PLR, a cheap and simple test, could predict poor FC in patients with stable CAD and recent elective PCI and help prioritize referral for cardiovascular rehabilitation in high-risk patients.

Keywords: cardiopulmonary exercise test; coronary artery disease; functional capacity; neutrophil to lymphocyte ratio; oxygen uptake; platelet to lymphocyte ratio.

Figure 1

Flow chart diagram of patients hospitalized in the Cardiovascular Rehabilitation Clinic Unit between January 2020 and June 2021. CAD—coronary artery disease, PCI—percutaneous coronary intervention, ACS—acute coronary syndrome, CPET—cardiopulmonary exercise test, % VO2 max—percentage of the predicted value of maximal oxygen uptake.

Figure 2

Platelet to lymphocyte ratio levels according to functional capacity groups.

Figure 3

Receiver operating characteristic curve of platelet to lymphocyte ratio for predicting poor functional capacity.