Leuko-platelet index as an independent predictor of in-hospital events in patients with non-ST elevation acute coronary syndrome

Abstract

Abstract Background Platelet activation and aggregation plays a fundamental role in the pathophysiology of acute coronary syndrome (ACS). Added to this is the activation of the coagulation cascade and a local and systemic inflammatory response. Both the white blood cell count and the platelet count were associated with a worse prognosis in ACS. The leuko-platelet index (LPI) combines the platelet and white blood cell count and has been described as a prognostic marker in these patients. Purpose The aim of this study is to evaluate if LPI is a predictor of in-hospital events and mortality in patients with non-ST elevation ACS (NSTEACS). Materials and methods A retrospective analysis of a multicentre registry of 25 coronary units of Argentina was performed. It was included patients witch diagnostic of NSTEACS. GRACE score and LPI was calculated with admission data. For LPI it was used the following formula: white blood cell count x platelet count/108. The upper quartile of LPI was chosen as the cut-off point for the LPI (LPI>24). According to GRACE and LPI was divided in 4 groups: Group 1 (GRACE<140 and LIP<24), Group 2 (GRACE<140 and LPI>24), group 3 (GRACE >140 and LPI<24) and group 4 (GRACE >140 and LPI >24). In-hospital follow-up was performed and was considered the combined end point of death from any cause, heart failure, and shock as primary end point and in-hospital mortality as secondary end point. Univariate and multivariate analysis was performed by logistic regression. Results 2170 patients with an age 65±11 years were included, 27.3% women, 63% non-ST infarction and 37% unstable angina, 37% had GRACE>140 (n=803) and 25% had LPI>24 (n=542). The combined end point was presented in 9.3% (n=203) with a in hospital mortality of 2.3% (n=50). The figure 1 shows the gradient of events according to the groups with GRACE 140 and ILP 24 (chi of trend: p=0.001 of combined end point and p=0.01 for in-hospital mortality). In the multivariate analysis, the LPI >24 and the GRACE score were independent predictors of the combined end point (OR 1.48 (95% CI 1.04–2.09), p=0.02 and OR 1.02 (95% CI 1.01–1.03), p<0.001; respectively) and mortality (OR 1.29 (95% CI 1.01–1.72), p=0.03 and OR 1.01 (1.003–1.03), p<0.001; respectively). C-Statistic of LPI and GRACE were similar both for the combined end point (LPI: 0.73 versus GRACE: 0.72, p=0.3) and for mortality (LPI: 0.70 versus GRACE: 0.73, p=0.4). Conclusions The LPI was an independent predictor of the combined point and in-hospital mortality, with a similar discrimination capacity as the GRACE score. The presence of LPI>24 in patients with GRACE>140 identifies a very high-risk subgroup. LPI is a very easily obtained marker that could be useful in risk stratification in patients with NSTEACS. Funding Acknowledgement Type of funding sources: None. Gradient of events according groups