Author + information
- Wee Kiat Ang1,
- Kah Hua Peck1,
- Violet Hoon1,
- Jason Kwok Kong Loh1,
- Fahim Haider Jafary1,
- David Foo1,
- Timothy James Watson1,
- Paul JL. Ong1 and
- Hee Hwa Ho1
Primary percutaneous coronary intervention (PPCI) is the preferred reperfusion therapy for patients presenting with STEMI if performed in a timely fashion. Several studies have demonstrated worse outcomes for patients presenting with STEMI during off-hours compared with during the workday.
We evaluated the clinical characteristics, door-to-balloon (D2B) time and clinical outcomes of STEMI patients who present during “off-hours” and “on-hours” in our single center registry.
From January 2009 to December 2014, 1661 patients (86 % male, the mean age of 58 ± 12 years) presented to our hospital for STEMI and underwent PPCI. 28% of patients had a known history of diabetes mellitus. Approximately 50% of patients underwent PPCI through radial artery access and received DES implantation. 60% of patients utilized the emergency ambulance services to come to the hospital. The rate of cardiogenic shock was 19% for the overall group.
We divided the STEMI patients into 2 groups according to the time of presentation to the emergency department. “Off-hour PCI” was defined by intervention performed during weekdays from 6 PM-8 AM, weekends and public holidays.
Data were collected retrospectively on baseline clinical characteristics, symptom onset to reperfusion time, D2B time, angiographic findings, therapeutic modality and hospital course.
The majority (62%) of STEMI patients in our registry presented during “off-hours”.
For the “off-hours” group, there was a higher proportion of male patients (88% vs 83%, p = 0.003) and they tend to be self-presenters (42% vs 36%, p=0.002). They also have a higher prevalence of hypertension, prior MI and prior PCI compared to “on-hours” group (p<0.05 for all comparisons).
Patients in the “off-hours” group had a longer D2B time (mean 55 ± 42 mins; median 56 mins) vs the “on-hours” group) (mean 47 ± 41; median 45 mins) (p=0.0002). The proportion of patients achieving D2B time <90 mins was also significantly lower in the “off-hours” group (80% vs 86%, p=0.005).
However, patients in the “off-hours” group had a shorter symptom to reperfusion time (mean 182 ± 198 vs 215 ± 248 mins, p=0.005).
There was no difference in the types of STEMI, the proportion of multivessel disease and cardiogenic shock for both groups. There were also no multi-ethnic or socio-economic differences between both groups.
The overall in-hospital mortality was 5.8%. However, there was no difference in the rate of in-hospital mortality for both groups (“off hours”: 6.6% vs “on-hours”: 4.6%, p =0.11).
Our registry showed that patients presenting with STEMI and receiving PPCI “off-hours” did not show worse outcomes compared with those arriving during regular daytime working hours. Although the former group had a significantly longer D2B time, they had a significantly shorter symptom onset to reperfusion time which may have impacted on the observed clinical outcomes.