Coronary Angiography after Cardiac Arrest without ST-Segment Elevation (COACT)

Aim of Study

In patients who are successfully resuscitated after a cardiac arrest in the absence of STEMI, would a strategy of immediate PCI be better than delayed angiography with respect to overall survival.

Design and Location

This was an investigator-initiated, RCT aimed at comparing immediate vs. delayed angiography in patients who were successfully resuscitated after cardiac arrest without ST elevation. The trial was run from January 2015, to July 2018. The study was exclusively conducted in Netherlands, with 19 participating centres.

Methodology

Inclusion: Patients who were successfully resuscitated after an out of hospital cardiac arrest, with an initial shockable rhythm.

Exclusion: Signs of STEMI on ECG. Patients were also excluded if they showed signs of shock, or obvious non-coronary cause of the arrest.

Method: Randomised 1:1 ratio to either immediate or delayed PCI. In the immediate angiogram group, the aim was an angiogram within 2 hours after randomisation. Delayed angiogram was considered after there was a form of neurological recovery. If a patient showed signs of cardiogenic shock, or recurrent ischaemia, an urgent angiography was performed. The choice of anticoagulant and revascularisation strategy was left to the discretion of the treating physicians. If there were signs of multi-vessel disease, then they were advised to use a revascularisation strategy that was based on the local heart team protocol and the SYNTAX (Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) criteria. Post-resuscitation care was in line with international resuscitation guidelines.

Primary Outcome

Telephone interview conducted at 90 days after randomisation with patient or family member – Survival at 90 days.

Secondary Outcomes

• survival at 90 days with good cerebral performance or mild or moderate disability
• myocardial injury quantified on the basis of troponin levels
• increase in creatine kinase and creatine kinase MB levels
• acute kidney injury
• time to target temperature
• duration of inotropic therapy
• neurologic status at discharge from the intensive care unit
• markers of shock
• recurrence of ventricular tachycardia requiring defibrillation or electrical cardioversion
• duration of mechanical ventilation
• major bleeding.

Statistics

The Investigators hypothesised that more patients in the immediate angiography group would survive to 90 days. They calculated that 251 subjects, in each group, would need to be enrolled to give the trial 85% power to detect a 40% difference (between immediate and delayed angiography). The sample size was increased by 10% to account for loss of patients, with a total of 552 patients being recruited.

Results

There was no survival benefit in patients in the immediate (64.5%) vs. delayed (67.2%) angiography (Odds ratio, 0.89, 95% CI, 0.62 to 1.27; P = 0.51). Median time from arrest to coronary angiogram was 2.3 hours, for the immediate group, vs. 121.9 hours for the delayed group.

There was no significant difference in single, two- or triple-vessel disease between the immediate and delayed angiogram groups. The percentage of patients with an acute unstable lesion was 13.6% and 16.9%, in the immediate and delayed angiogram groups respectively.

There was no difference between the two groups in terms of duration of mechanical ventilation, renal replacement therapy or ionotropic support.

Conclusions/Discussions

There is no significant difference between immediate and delayed angiography in survival at 90 days. The study findings do not corroborate previous observational studies that an immediate angiogram in patients without a STEMI had a survival benefit.

Stated Limitations from the Study

Was the sample of patients at low-risk of coronary events, and therefore not a true representation of patients that have had an OOHCA secondary to a true myocardial event. Only ~20% from both groups had ‘critically stenotic lesions’, with only 25-35% undergoing an intervention.

Discussion from Journal Club Meeting (?Change of Practice)

Value of study: Could there be a change in guidelines and less focus on pushing for a coronary angiogram, irrespective of the timing of the said angiography, since there is no benefit in survival. 

Given the above findings, we agreed that rather than the importance of revascularisation, it was rather the result of the neurological insult secondary to the cardiac arrest that leads to the eventual deaths of such patients, rather than the stenotic lesion itself.

Summary by Dr S Sivalokanathan. Journal Club Meeting 20 February 2020.

Image from https://commons.wikimedia.org/wiki/File:Coronary_Angiography.jpg