TACTICS Timing of Angiography Substudy - TACTICS Timing of Angiography Substudy

Description:

This substudy of the TACTICS/TIMI-18 study of early invasive versus conservative therapy in unstable angina/non-ST-elevation myocardial infarction (UA/NSTEMI) addressed the relationship of timing of angiography with clinical outcomes among patients in the invasive arm of the trial.

Hypothesis:

Patients with acute coronary syndromes (ACSs) undergoing earlier angiography would have improved outcomes compared to patients undergoing delayed angiography.

Study Design

Study Design:

Patients Enrolled: 1,078
Mean Follow Up: 6 months
Mean Patient Age: Mean 62 years
Female: 30

Patient Populations:

Patients from the invasive arm of the trial were included in the analysis. In order to be enrolled, patients were >18 years of age with suspected ACS by the following criteria: 1) angina with an accelerated pattern, prolonged (>20 minutes) duration, or recurrent episodes at rest within the prior 24 hours; 2) candidacy for revascularization; and 3) at least one of the indicators of cardiac ischemia or injury: ≥0.05 mV ST-segment depression, transient ≥0.1 mV ST-segment elevation, or ≥0.3 mV T-wave inversion in two or more leads not known to be old, elevated cardiac markers, or a documented history of coronary disease.

Exclusions:

Persistent ST-segment elevation, coronary revascularization within six months, excess bleeding risks, left bundle branch block or paced cardiac rhythms, severe congestive heart failure, cardiogenic shock, and chronic kidney disease (serum creatinine> 2.5 mg/dl)

Primary Endpoints:

Composite of death, myocardial infarction, and rehospitalization for ACS at six months

Secondary Endpoints:

Individual components of the composite endpoint

Drug/Procedures Used:

In the TACTICS trial, patients were treated with the glycoprotein IIb/IIIa antagonist tirofiban and randomized to a strategy of early invasive management (early catheterization and angiography) or conservative, ischemia-driven management. This substudy addressed the nonrandomized timing of angiography among patients randomized to the early invasive arm of the trial.

Concomitant Medications:

All patients received aspirin, heparin, and tirofiban.

Principal Findings:

A total of 1,078 patients in the early invasive arm of TACTICS had available times to angiography. In general, there were no significant differences in baseline characteristics among patients undergoing angiography at various time intervals from randomization, although revascularization with either percutaneous coronary intervention (PCI) or coronary artery bypass graft was slightly more frequent among patients with early catheterization.

Overall rates of the composite endpoint were similar among patients receiving early or late (>48 hours) angiography (15.4% vs. 19.5%, p=0.34). However, there was a trend for a greater rate of myocardial infarctions prior to catheterization in patients undergoing catheterization after 48 hours (2.6% vs. 0.6%, p=0.11). There was no identified benefit of very early angiography (<6 hours) in this study.

Interpretation:

In this nonrandomized sample of patients from the invasive arm of TACTICS/TIMI-18, even earlier angiography was not associated with improved clinical outcomes. These findings are in contrast to those of the ISAR-COOL study, a randomized trial of early versus delayed catheterization in a similar patient population. However, angiography was performed at almost four days in patients in the delayed invasive arm of the ISAR-COOL trial.

In the current analysis, the potential for confounding (i.e., uncontrolled reasons for patients to undergo early or late catheterization) presents difficulties in interpreting the results in isolation. Nonetheless, the finding of a trend for less myocardial infarctions prior to the catheterization among patients treated within 48 hours is notable.

References:

McCullough PA, Gibson CM, Dibattiste PM, et al. Timing of angiography and revascularization in acute coronary syndromes: an analysis of the TACTICS-TIMI-18 trial. J Interv Cardiol 2004;17:81-6.

Clinical Topics: Acute Coronary Syndromes, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Aortic Surgery, Interventions and ACS

Keywords: Myocardial Infarction, Acute Coronary Syndrome, Platelet Aggregation Inhibitors, Catheterization, Fibrinolytic Agents, Coronary Artery Bypass, Tyrosine, Percutaneous Coronary Intervention


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