Outcomes of patients calling emergency medical services for suspected acute cardiovascular disease

Adequate health care is increasingly dependent on prehospital systems and cardiovascular (CV) disease remains the most common cause for hospital admission. However the prevalence of CV dispatches of emergency medical services (EMS) is not well reported and survival data described in clinical trials and registries are subject to selection biases. We aimed to describe the prevalence and prognosis of acute CV disease and the effect of invasive treatment, in an unselected and consecutive prehospital cohort of 3,410 patients calling the national emergency telephone number from 2005 to 2008 with follow-up in 2013. Individual-level data from national registries were linked to the dedicated EMS database of primary ambulance dispatches supported by physician-manned emergency units. Outcome data were obtained from the Central Population Registry, the National Patient Registry, and the National Registry of Causes of Death. In patients calling the national emergency telephone number, a CV related ambulance alarm code was given in 2,541 patients of 3,410 patients (74.5%) resulting in 2,056 of 3,410 primary CV discharge diagnoses (60.3%) with a 30-day and 5-year all-cause mortality of 24.5% and 46.4%, respectively. Stroke, acute heart failure, and ST-segment elevation myocardial infarction (STEMI) carried a 25- to 50-fold adjusted mortality hazard during the first 4 days. In patients with suspected STEMI, 90.5% had an acute angiography performed. Nontransferred, nonreperfused patients with STEMI (9.1%) carried 80% short-term mortality. Noninvasive management of non-ST-segment elevation myocardial infarction was common (37.9%) and associated with an increased adjusted long-term mortality hazard (hazard ratio 4.17 [2.51 to 8.08], p <0.001). Survival in 447 out-of-hospital cardiac arrest patients (13.1%) was 11.6% at 30 days. In conclusion, patients with a CV ambulance alarm call code and a final CV discharge diagnosis constitute most patients handled by EMS with an extremely elevated short-term mortality hazard and a poor long-term prognosis. Although co-morbidities and frailty may influence triage, this study emphasizes the need for an efficient prehospital phase with focus on CV disease and proper triage of patients suitable for invasive evaluation if the outcomes of acute heart disease are to be improved further in the current international context of hospitals merging into highly specialized entities resulting in longer patient transfers.