Regional systems of care after out-of-hospital cardiac arrest in the UK: premier league care saves lives

Out-of-hospital cardiac arrest (OHCA) is a common condition in the UK with an estimated annual incidence of 60,000.¹

Clinical outcomes for this group can only be described as awful. Not only is the condition usually fatal, with survival to hospital admission/hospital discharge rates of 24% and 8%, respectively,² but the cost of survival is frequently significant morbidity with the largest observational study ever assembled of over 400,000 OHCA victims recently reporting severe cerebral disability in the majority of survivors.³ Predictors of survival include time to first emergency response; witnessed arrest; effective bystander cardiopulmonary resuscitation; initial shockable rhythm; early defibrillation and prehospital return of spontaneous circulation (ROSC).² Such variables demonstrate how survival is largely determined by the actions of the general public and immediate access to automated defibrillation equipment.

Despite national public awareness campaigns, wide geographical variations in survival to discharge rates of between 1% and 8% are reported in the UK.⁴ The post-cardiac arrest care pathway for OHCA victims successfully resuscitated in the field varies, and may in part account for this observation. Highlighting the positive end of the survival spectrum, a Premier League football player who collapsed on the field in cardiac arrest ultimately survived with no reported neurological disability after total cardiac arrest duration of more than 70 minutes. The player concerned was transported to a tertiary cardiac centre bypassing two district hospitals en-route, while apparently in sustained cardiac arrest.⁵

Coronary artery disease accounts for between 40% and 90% of OHCA,⁶ with rarer cardiac causes including cardiomyopathies, channelopathies, systemic and infiltrative diseases and acute myocarditis. Currently, specialist cardiac facilities are routinely only made immediately available for those whose ROSC electrocardiogram clearly demonstrates ST-segment elevation (STE). This would implicate acute coronary artery occlusion as the culprit pathology, with the patient standing to benefit from primary percutaneous coronary intervention (PPCI).

In 2010, the London Ambulance Service introduced a pathway of care to convey these patients directly to one of eight heart attack centres, where survival to discharge rates of up to 80% have been reported in those with ROSC on arrival.⁷ Data from the PROCAT – (Parisian out-of-hospital cardiac arrest) registry looking at coronary intervention and OHCA, would however suggest that PCI may confer a mortality benefit to a group beyond those displaying electrocardiographic STE.⁸

In 301 ROSC patients without STE routinely taken to coronary angiography, 78 had successful PCI with survival correspondingly increasing from 31% to 47% in this group. Importantly, this group only included OHCA of presumed cardiac origin. Such a group may be difficult to identify in the prehospital setting when other clinical data such as presence of chest pain and risk factor profile is not readily available, practically it may thus be easier to define them as those in whom a non-cardiac cause for the arrest is not immediately forthcoming. PROCAT findings would support previous work⁹ demonstrating that absence of STE does not exclude acute coronary occlusion, thus surely limiting its sensitivity and specificity as a selection tool to identify OHCA survivors who stand to benefit from immediate coronary angiography. Indeed, in a large Australian cohort of 2900 unselected ROSC patients, transfer to hospitals with 24-hour cardiac interventional facilities¹⁰ was shown to improve survival, although improved survival here is likely multifactorial with access to cardiac critical care facilities making a contribution.

Optimal post-cardiac arrest care is resource intensive, requiring input from a variety of specialties: cardiologists with a special interest in intervention and dysrrhythmias; intensivists; neurologists; specialist nurses and a variety of therapists. Such complex care may be best delivered by a smaller number of experienced hospitals dealing with a higher volume of patients. Indeed, hospitals treating more than 40 such patients annually have been shown to have higher rates of survival to discharge¹¹ and supports the evolution of designated ‘cardiac arrest centres’; a concept already endorsed by the American Heart Association.¹² Within such centres, specialist treatments such as PPCI and therapeutic hypothermia (shown to improve neurological outcomes and survival¹³) can be instituted in a timely and well-rehearsed fashion by teams regularly treating survivors of OHCA. The development of such regional organization will inevitably raise concerns regarding longer transfer times for critically ill patients, though data exist to refute such fears.¹⁴

Furthermore, regional systems of care have been successfully instituted in the treatment of other time sensitive conditions such as STEMI, stroke and more recently trauma. Although providing only anecdotal evidence, the recent case of the professional footballer demonstrates how access to specialized care in selected cases can provide astounding results. Here, although likely non-ischaemic, the underlying cause of arrest was undoubtedly cardiac. With coronary interventional and other specialist facilities seemingly offering wide ranging benefit, it would seem attractive to suggest that access to specialist centres may benefit a broader subgroup of OHCA cardiac patients, beyond those in whom STE myocardial infarction after ROSC is clearly evident. However, exactly who stands to benefit the most from a routine admission policy, beyond this well-defined group, remains poorly understood.

Routine admission of all OHCA patients to specialist centres would no doubt impose too large a burden on tertiary intensive care resources and in most cases would be of little benefit to the victim, even admission limited to those attaining ROSC, would present novel problems. Here, ROSC attained in a district hospital would warrant interhospital transfer (IHT), when in most of these cases ROSC would not imply meaningful survival is possible, indeed, many resuscitation attempts are terminated after a successful restoration of circulation. IHT in those deemed suitable would mean transferring critically ill patients long distances, placing an unpredictable burden on high-dependency ambulance crews, as well as receiving centres. Prehospital ROSC is however among the strongest predictors of survival.² Those in this group in whom a non-cardiac cause to the arrest is not immediately forthcoming may indeed stand to benefit the most from routine access to specialist care.

Comparing clinical outcomes in OHCA patients is fraught with difficulty. The population is heterogeneous with a broad variety of clinical factors impacting upon survival. National standardized data collection would afford an understanding of how these factors interact with admitting institution, to ascertain which subgroup of the total OHCA cohort beyond those displaying electrocardiographic STE stand to benefit the most from routine access to specialist care. A national database of OHCA patients will allow the identification of appropriate selection criteria for those most likely to benefit, on which feasibility for the development of a national network of designated ROSC centres can be assessed.