Relationship between systemic inflammation indices and time of symptom onset in cardiac remodeling after first ST-segment elevation myocardial infarction

Background: Circadian variations play a pivotal role in both leukocyte trafficking and inflammatory response. This may affect the course of cardiac healing after myocardial infarction (MI).Aims: The present study investigated the relationship between the systemic immune inflammation (SII) index and the systemic inflammation response index (SIRI), two new inflammation indices integrating white blood cell subsets and platelets, and the time of onset of symptoms in left ventricular adverse remodeling (LVAR) after ST-segment elevation MI (STEMI).Methods: In this retrospective study, we included 512 patients with first-time STEMI. The time of onset of symptoms was divided into 4 intervals: 06:00-11:59, 12:00-17:59, 18:00-23:59, and 00:00-05:59. The endpoint was LVAR, defined as an increase in left ventricular end-diastolic and end-systolic volume by >= 12% at 6 months.Results: The time of onset of chest pain most often occurred between 06:00 and 11:59 AM. In this window of time, median SII and SIRI indices were higher than in other time intervals. An increased SIRI level (odds ratio [OR], 3.03; P <0.001), symptom onset in the morning hours (OR, 2.92; P = 0.03), and an increased Global Registry of Acute Coronary Events (GRACE) score (OR, 1.16; P <0.001) were determined as independent predictors of LVAR. The threshold value of the SIRI to discriminate between patients with and without LVAR was >2.5 (area under the curve [AUC], 0.84; P <0.001). The SIRI showed superior diagnostic performance compared to the SII index.Conclusions:In STEMI patients, an increased SIRI was independently associated with LVAR. This was more pronounced between 06:00 and11:59 AM. Despite differences across circadian periods, the SIRI may be a potential screening tool for identifying LVAR patients at long-term risk of heart failure.