Arrival by ambulance in acute heart failure: insights into the mode of presentation from Acute Studies of Nesiritide in Decompensated Heart Failure (ASCEND-HF).

OBJECTIVES Limited data exist assessing the relationship between ambulance versus self-presentation and outcomes in patients with acute heart failure (AHF). SETTING Clinical trial sites in North America. PARTICIPANTS 1068 patients enrolled in the Acute Studies of Nesiritide in Decompensated Heart Failure (ASCEND-HF) trial. PRIMARY AND SECONDARY OUTCOME MEASURES The association between ambulance use and dyspnoea improvement, 30-day mortality or HF rehospitalisation and 180-day mortality. RESULTS Of the 1068 patients in the substudy, 832 (78%) self-presented (SP) and 236 (22%) patients presented via ambulance. Patients presenting via ambulance were older, more likely to be female, have a higher ejection fraction but similar natriuretic peptide levels as patients who SP. Patients presenting by ambulance (compared with SP) trended towards more dyspnoea improvement at 6 (p=0.09) and 24 h (p=0.10). The co-primary end point (30-day mortality or HF rehospitalisation) was similar between groups (ambulance 12.2% vs SP 11.4%, p=0.74). Patients who presented by ambulance had a higher 30-day and 180-day mortality rate than those who SP (30-day: 4.3% vs 2.2%, p=0.08; 180-day: 15.1% vs 10.3%, p=0.04). After adjustment for baseline characteristics, patients arriving by ambulance (compared with SP) had a 2-fold high risk of 30-day mortality (OR 2.12, 95% CI 0.94 to 4.79), but no relationship to the composite of 30-day mortality/HF rehospitalisation (OR 1.01, 95% CI 0.63 to 1.63). CONCLUSIONS Among patients with AHF, 30-day and 180-day mortality is 1.5-2 times higher for those with presenting via ambulance compared with patients who self-present. Understanding patient-related and system-related factors of ambulance use for patients with AHF is important. TRIAL REGISTRATION NUMBER NCT00475852.