Patients, who reach hospital during off working hours for treatment for heart attacks, may be more at risk from death and delayed restoration of normal blood flow, said a research findings in the latest issue of JAMA.
Reperfusion therapy (restoration of blood flow to an organ or tissue) with either fibrinolytic therapy (medication for dissolving blood clots) or percutaneous coronary intervention (PCI; procedures such as angioplasty in which a catheter-guided balloon is used to open a narrowed coronary artery) reduces the risk of death for eligible ST-segment elevation myocardial infarction (STEMI; a certain finding on an
electrocardiogram following a heart attack) patients. The shorter the time from symptom onset to treatment, the greater the survival benefit with either therapy.
Scientists of Kaiser Permanente, Denver, had examined the relationship between time of day and day of week and reperfusion treatment times for STEMI patients treated with fibrinolytic therapy or PCI. The authors write that understanding the reasons for variation in reperfusion treatment times by patient arrival period, and whether such variation is common to all hospitals and to both fibrinolytic therapy and PCI, could inform the design and targeting of interventions to improve timely reperfusion.
The study included 68,439 patients with STEMI treated with fibrinolytic therapy and 33,647 treated with PCI from 1999 through 2002. The researchers classified patient hospital arrival period into regular hours (weekdays, 7 a.m.-5 p.m.) and off-hours (weekdays 5 p.m.-7 a.m. and weekends).
Patients arriving during off-hours had significantly higher adjusted in-hospital death rates than patients arriving during regular hours. This mortality difference was reduced by 43 percent when researchers adjusted for differences in reperfusion treatment times, suggesting that the higher off-hours mortality was due in part to longer reperfusion treatment times.
The researchers add that this study demonstrates that delays to PCI during off-hours are common to all types of hospitals, including high-volume PCI centers.