Читать книгу Practical Cardiovascular Medicine - Elias B. Hanna - Страница 151

The large COACT trial randomized comatose patients with resuscitated OHCA, whose initial rhythm was VT/VF, and whose post-arrest ECG did not show STEMI (~70% of OHCA), to immediate coronary angiography vs. coronary angiography delayed until neurological recovery. The 90-day survival was similar in both groups (~65%).¹⁷⁸ There was no benefit of immediate coronary angiography, even though the trial selected patients with favorable features for neurological recovery (mostly witnessed arrest, with only 2 min from arrest to basic life support, and 15 min to return of spontaneous circulation, pH 7.2). Importantly, while most patients had CAD (~65%, including prior PCI or CABG in ~35%), most of this CAD was chronic stable CAD (CTO 37%) and VT/VF was related to ischemic cardiomyopathy and old scars/infarcts rather than active ischemia; only ~5% of patients had acute thrombotic occlusion and ~15% had unstable coronary lesions. Another large trial, TOMAHAWK, confirmed this lack of benefit from immediate coronary angiography, which was conversely associated with a trend toward more death and severe neurological deficit; a culprit coronary lesion was identified in 39% of patients.^179–181

The initial neurological status, upon return of spontaneous circulation, is a strong determinant of survival. In patients who regain consciousness early on or who display response to pain or stimuli, the survival to hospital discharge with good neurological status is >90%.^181,182 Conversely, the prognosis is particularly poor in patients who are totally unresponsive, who are missing multiple brainstem reflexes, or who display early myoclonic jerks.

In addition, older age (>75-80), initial non-shockable rhythm, unwitnessed arrest or delayed initiation of cardiac compressions (>10 min), prolonged resuscitation before return of spontaneous circulation (>20 min, >3 doses of epinephrine required), and low pH<7.2 indicate a poor likelihood of neurological recovery and argue against immediate coronary angiography, particularly in the absence of ST elevation (ESC).^2,183 Proper cardiac compressions only provide ~20% of the normal cardiac output.

Overall, immediate coronary angiography is indicated in the following cases (ESC, SCAI 2020):^2,177

 Post-resuscitation ECG consistent with STEMI and favorable neurological predictors are present. If multiple unfavorable predictors are present in a comatose patient, treatment is individualized, and coronary angiography may be deferred (SCAI).

 In the absence of ST elevation, quickly evaluate for non-cardiac causes (intracranial hemorrhage, respiratory failure, PE, sepsis), take into consideration Q waves (old scar?) and pronounced ST depression (active ischemia?), and consider urgent echocardiography. Coronary angiography does not need to be performed immediately, unless: (a) myocardial ischemia appears likely, with (b) persistent shock and (c) no poor neurological predictors.

Note that, when indicated, immediate coronary angiography is performed in patients who are successfully resuscitated and whose systemic pressure is maintained on reasonable and stable doses of vasopressors. The performance of PCI in patients actively receiving chest compressions, using an external compression device, did not improve the grim mortality in one study and was not recommended in an expert viewpoint.^176,184

Note: 5–15% of patients with ST elevation and OHCA do not have acute coronary occlusion.^179-181 In those cases, ST elevation is related to a myocardial injury from the cardiac arrest itself, hyperkalemia, PE, or intracranial hemorrhage. One Korean study has shown that up to 19% of OHCA patients with ST elevation or, more so, ST depression have intracranial hemorrhage as a cause of the OHCA.