NEW YORK (Reuters Health) Apr 29 - Results of a study establish that neutrophilia and lymphopenia, expressed as a high neutrophil-to-lymphocyte ratio (N/L), are strongly related to long-term mortality in patients with ST-segment elevation myocardial infarction (STEMI).
"This ratio showed higher discriminative ability than total white blood cell count," Dr. Julio Nunez from the University of Valencia, Spain, noted in comments to Reuters Health.
Dr. Nunez and colleagues determined the association of N/L maximum value with mortality and compared its predictive ability with total white blood cell maximum count (WBC) in 470 STEMI patients admitted to a single university hospital. Measurements were obtained at admission and daily for the first 96 hours after admission. During a median follow up of 3 years, 106 patients died (22.6%).
"In this study, we showed that N/L-max measured within the first 96 hours after onset of STEMI symptoms carried significant prognostic value for subsequent mortality," the authors report in the March 15 issue of the American Journal of Cardiology.
The mortality rate during follow up in the first quintile of N/L-max was 6.4%. The highest mortality rates were seen in patients in the fourth and fifth quintiles -- 34% and 47.9%, respectively -- which translated to hazard ratios of 2.58 and 4.20, respectively.
"This association remained significant after adjusting for key predictors including age, reperfusion criteria, renal function, and surrogates of myocardial extensions, such as left ventricular dysfunction, systolic blood pressure and Killip's classification," the investigators note.
The overall discriminatory ability of N/L-max was superior to that of WBC-max, they also report.
These findings were not unexpected, Dr. Nunez told Reuters Health, "because inflammation response is associated with adverse prognosis in the setting of acute coronary syndromes, and commonly this response is characterized by neutrophilia and lymphopenia, so N/L seems a better inflammation marker than total white blood cells."
His group hypothesizes that "patients with high N/L ratio during the acute phase of myocardial infarction could be a subgroup with higher benefit from an aggressive treatment."
"Further studies are needed to clarify this point," Dr. Nunez said.
Am J Cardiol 2008;101:747-752.