The Relation between the Timing of Percutaneous Coronary Intervention and Outcomes in Patients with Acute Coronary Syndrome with Routine Invasive Strategy - Data from Taiwan Acute Coronary Syndrome Full Spectrum Data Registry.

Background: Several large trials have indicated that a routine invasive strategy was favored for high-risk patients with non-ST-elevation acute coronary syndromes. However, the optimal timing for this intervention is unclear.

Methods: We included patients with unstable angina or non-ST elevation myocardial infarction (NSTEMI) undergoing percutaneous coronary intervention (PCI) from the Taiwan acute coronary syndrome registry. Thrombolysis in Myocardial Infarction (TIMI) score was used to stratify our patients into three groups: low (TIMI 0-2), intermediate (TIMI 3-4) and high risk (TIMI 5-7).We analyzed outcomes according to the timing of PCI.

Results: Overall, 984 patients were included in this study. For primary outcomes including cardiac death and recurrent myocardial infarction, early PCI within 24 hours did not show benefits over late PCI (24-72 or > 72 hours) (p > 0.05) in the low and intermediate risk groups. However, in the high risk group, patients who underwent PCI after 72 hours had significantly worse primary outcomes than those who underwent PCI within 24-72 hours. For secondary outcomes including non-cardiac death, unplanned revascularization, and major bleeding, the events rate was significantly higher for early or delayed PCI in low-risk patients when compared with patients who underwent PCI within 24-72 hours.

Conclusions: In our study, for high-risk NSTE-ACS patients, PCI within 24-72 hours from symptom onset is demonstrably the optimum time for PCI. Delayed PCI over 72 hours is associated with the worst outcomes and should be avoided. For patients with low risks, routine early PCI < 24 hours after PCI is not beneficial.

Key Words: Acute coronary syndrome; Early invasive strategy.