The clinical benefit of manual thrombus aspiration (TA) during primary percutaneous coronary intervention (PPCI) in patients with ST-segment elevation myocardial infarction (STEMI) remains uncertain. This study assessed the impact of circadian rhythms on the effectiveness of manual TA.
We conducted an observational study of patients enrolled in the Acute Myocardial Infarction in Switzerland Plus registry. STEMI patients undergoing PPCI with (TA group) or without (PCI-alone group) manual TA were divided based on time-of-day symptom onset: group 1 (00:00-05:59), group 2 (06:00-11:59), group 3 (12:00-17:59) and group 4 (18:00-23:59). The primary endpoint was circadian variation of myocardial infarction (MI) size. The secondary endpoint was in-hospital all-cause mortality. Between 2009 and 2014, 3648 patients underwent PPCI (TA, 49%). After propensity-score matching, 2860 patients were included. Minimal myocardial Injury was observed in groups 2 and 3 (peak creatine kinase level group 1, 2723 ± 148 U/l; group 2, 2493 ± 105 U/l; group 3, 2550 ± 106 U/l; group 4, 2952 ± 144 U/l; p = 0.044) in the TA group, whereas no time-of-day dependence was found in PCI-alone group. After periodic sinusoidal regression analysis, a circadian relationship between time-of-day symptom onset and MI size was demonstrated in the TA group (p < 0.001). In-hospital all-cause mortality was 3.4% in the TA group and 4.3% in the PCI-alone group (p = 0.20).
In this large registry of STEMI patients, manual TA did not reduce in-hospital all-cause mortality. Nonetheless, there was a circadian dependence of TA effectiveness with greatest myocardial salvage for patients with symptom onset between 06:00 and 17:59.