Management of Patients After Out of Hospital Cardiac Arrest
Management of Patients After Out of Hospital Cardiac Arrest
The commonest cause of ventricular fibrillation or ventricular tachycardia cardiac arrest is cardiovascular disease, especially myocardial ischaemia. In a study of 714 all-rhythm patients with OHCA referred to a tertiary centre in Paris, 435 (61%) had no obvious extracardiac cause and underwent coronary angiography—304 (70%) had at least one significant coronary lesion. However, it remains unclear whether the lesion was responsible for the arrest and whether patients after ROSC really benefit from immediate angiography and revascularisation. Patients with cardiac arrest have been excluded from most acute myocardial infarction trials, which has created a 'knowledge gap' for these patients. While non-cardiac arrest patients with ST-elevation infarctions clearly benefit from immediate angiography/PCI, we lack data for patients after cardiac arrest. There is no consensus and clinical practice is variable among medical centres and cardiologists. An ECG should be recorded as soon as possible after ROSC to assess ST elevation or (new) left bundle branch block. The rationale for urgent angiography is that early revascularisation may minimise myocardial necrosis, which will increase cardiac output, reduce the likelihood of arrhythmias and increase cerebral blood flow. Several non-randomised observational studies have demonstrated survival benefit from early angiography after OHCA compared with no or delayed angiography/coronary intervention. However, studies have also highlighted an increased complication risk if early angiography is performed in these patients.
Angiography is often delayed until the neurological status of the patient can be determined accurately. A common perception among cardiologists is that patients with OHCA have a poor survival rate and often remain neurologically impaired—recent data showing favourable outcomes in these patients should change this view. Cardiologists and hospitals in the USA and some European countries, such as the UK, are being publicly scored according to their PCI outcomes and deaths from OHCA will adversely affect the overall rating of the hospital and the provider. This is problematic; the neurological status is difficult to assess reliably during the first few days after OHCA, especially in those undergoing hypothermia treatment.
Overall, it remains unknown which patients will benefit from early angiography/PCI after resuscitation from cardiac arrest. Guidelines advocate early angiography for patients with ST elevation on a post-resuscitation 12-lead ECG. However, the ECG has poor accuracy in this setting. The absence of ST elevation does not exclude the presence of critical coronary stenosis. In a recent study, the negative predictive value for a critical lesion was only about 42%, while 58% still had a critical lesion despite the absence of ST elevation. In approximately 50% of patients without ST elevation after arrest, a significant lesion was found and stented; however, evidence to support this strategy is lacking. Unless there is a thrombotic occlusion, angiography is an insufficient method to detect vulnerable coronary lesions. Despite this lack of evidence, we strongly advocate that all patients with ROSC should undergo early coronary angiography if there is no obvious non-cardiac cause of the cardiac arrest, regardless of the initial post-ROSC ECG since the predictive value of the post-ROSC ECG is low. Early information about the coronary circulation can guide in-hospital management beyond a coronary intervention and, in patients in cardiogenic shock, an intra-aortic balloon pump or other support devices can be implemented immediately to improve cardiac output. In our opinion, an early angiogram provides more benefit than harm, but this strategy would have significant resource implications, especially in cardiac centres.
Immediate Cardiac Management and Coronary Angiography
The commonest cause of ventricular fibrillation or ventricular tachycardia cardiac arrest is cardiovascular disease, especially myocardial ischaemia. In a study of 714 all-rhythm patients with OHCA referred to a tertiary centre in Paris, 435 (61%) had no obvious extracardiac cause and underwent coronary angiography—304 (70%) had at least one significant coronary lesion. However, it remains unclear whether the lesion was responsible for the arrest and whether patients after ROSC really benefit from immediate angiography and revascularisation. Patients with cardiac arrest have been excluded from most acute myocardial infarction trials, which has created a 'knowledge gap' for these patients. While non-cardiac arrest patients with ST-elevation infarctions clearly benefit from immediate angiography/PCI, we lack data for patients after cardiac arrest. There is no consensus and clinical practice is variable among medical centres and cardiologists. An ECG should be recorded as soon as possible after ROSC to assess ST elevation or (new) left bundle branch block. The rationale for urgent angiography is that early revascularisation may minimise myocardial necrosis, which will increase cardiac output, reduce the likelihood of arrhythmias and increase cerebral blood flow. Several non-randomised observational studies have demonstrated survival benefit from early angiography after OHCA compared with no or delayed angiography/coronary intervention. However, studies have also highlighted an increased complication risk if early angiography is performed in these patients.
Angiography is often delayed until the neurological status of the patient can be determined accurately. A common perception among cardiologists is that patients with OHCA have a poor survival rate and often remain neurologically impaired—recent data showing favourable outcomes in these patients should change this view. Cardiologists and hospitals in the USA and some European countries, such as the UK, are being publicly scored according to their PCI outcomes and deaths from OHCA will adversely affect the overall rating of the hospital and the provider. This is problematic; the neurological status is difficult to assess reliably during the first few days after OHCA, especially in those undergoing hypothermia treatment.
Overall, it remains unknown which patients will benefit from early angiography/PCI after resuscitation from cardiac arrest. Guidelines advocate early angiography for patients with ST elevation on a post-resuscitation 12-lead ECG. However, the ECG has poor accuracy in this setting. The absence of ST elevation does not exclude the presence of critical coronary stenosis. In a recent study, the negative predictive value for a critical lesion was only about 42%, while 58% still had a critical lesion despite the absence of ST elevation. In approximately 50% of patients without ST elevation after arrest, a significant lesion was found and stented; however, evidence to support this strategy is lacking. Unless there is a thrombotic occlusion, angiography is an insufficient method to detect vulnerable coronary lesions. Despite this lack of evidence, we strongly advocate that all patients with ROSC should undergo early coronary angiography if there is no obvious non-cardiac cause of the cardiac arrest, regardless of the initial post-ROSC ECG since the predictive value of the post-ROSC ECG is low. Early information about the coronary circulation can guide in-hospital management beyond a coronary intervention and, in patients in cardiogenic shock, an intra-aortic balloon pump or other support devices can be implemented immediately to improve cardiac output. In our opinion, an early angiogram provides more benefit than harm, but this strategy would have significant resource implications, especially in cardiac centres.
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