Dallas, TX - A new analysis of AMI patients in the Get with the Guidelines CAD database suggests that people admitted to the hospital for AMI on weekends, holidays, or on weeknights receive PCI less frequently but have no overall increase in in-hospital mortality [1].

Dr Hani Jneid (Harvard Medical School, Boston, MA) and colleagues report their findings in a paper published online April 21, 2008 in Circulation. Their study is the latest to illuminate gaps in optimal guideline-based treatments based on the time of day that patients arrive at the hospital.

But in Jneid et al's analysis, which included almost 63 000 patients—54% of whom arrived at the hospital during "off" hours (weeknights, weekends, or holidays)—patients appeared to receive different types of reperfusion treatment for their AMI but did not experience higher mortality based on time of day. Compared with patients arriving during "regular" hours, patients arriving during off-hours had longer door-to-balloon times (85 minutes vs 110 minutes) and were less likely, overall, to receive PCI and more likely to receive fibrinolysis.

To heartwire, Jneid admitted that he was somewhat surprised by the lack of in-hospital mortality differences, given the disparities in door-to-balloon times and use of PCI/revascularization. "There are several explanations for this," he said. "The slight differences in the use of revascularization among patients during off-hours vs regular hours, although statistically significant because of the large number of patients, might not be as clinically relevant. In addition, most trials have supported the benefits of early revascularization on composite cardiovascular end points but generally found no impact on acute mortality. On the other hand, in our analysis, patients with STEMI arriving during off-hours were more likely to receive fibrinolytics, which resulted in no net differences in overall reperfusion rates."

Jneid also predicted that long-term cardiovascular mortality and morbidity rates would be different in patients treated during on- vs off-hours.

Jneid et al's findings, while reassuring, are at odds with those from the National Registry of Myocardial Infarction (NRMI), which pointed to higher rates of in-hospital death among patients arriving during off-hours, and the MIDAS analysis, which found greater mortality in AMI patients on weekends. But the NRMI study, Jneid explained to heartwire, looked only at STEMI patients and included "transfer-out" patients who were assumed to be alive, while the MIDAS study had much lower rates of catheterization and revascularization and was conducted solely in the state of New Jersey. The current results may reflect more up-to-date treatment strategies across a wider spectrum of patients and hospitals. Of note, however, the authors saw no differences in mortality during on- or off-hours in subgroups stratified by STEMI or non-STEMI or by age and sex.

"These gaps in the healthcare system represent important opportunities to work on and thus have major implication for healthcare providers, hospitals, and policy makers," Jneid told heartwire. Moreover, "The fact that the timeliness of primary PCI when selected was still suboptimal points out to the ongoing system challenges in achieving rapid system activation and staff mobilization during off-hours. This is an area where hospitals and physicians should continue to work to enhance."