Shorter reperfusion times for patients with ST-segment elevation myocardial infarction (STEMI) are associated with fewer cases of in-hospital heart failure and fewer readmissions for heart failure over the next 30 days, according to an observational study from Singapore published in Circulation: Cardiovascular Quality and Outcomes.
The researchers studied nearly 7,600 patients undergoing emergency PCI for STEMI from 2007 to 2013 using the Singapore Myocardial Infarct Registry. Although several studies have looked at the link between time to primary PCI (pPCI) and mortality, few have studied its impact on heart failure outcomes, according to senior author Mark Y. Chan, MBBS, PhD, with the National University of Singapore.
“Earlier reperfusion is expected to improve myocardial salvage, leading to a reduction in HF events during the early post-pPCI period and on a longer-term basis,” the researchers hypothesized.
Chan et al. studied the temporal changes in time to reperfusion, as well as changes in heart failure hospitalizations over time. They defined the variable (FTD) as the time to reperfusion from a patient’s first medical contact—either from a paramedic, medical triage or arrival in the emergency department, whichever came first.
Among their findings:
- Median FTD time dropped from 91 minutes in 2007 to 58 minutes in 2013.
- Compared to FTD times below 60 minutes, 60-90 minutes was associated with an 18 percent increased risk of in-hospital heart failure. The risk increases jumped to 59 percent and 67 percent for 90-120 minutes and more than two hours, respectively.
- Among the nearly 1,200 patients with heart failure upon arrival, FTD times of more than 90 minutes were associated with almost triple the risk of 30-day HF readmissions compared to patients with FTD times of less than an hour.
Despite these observations, the authors noted death rates remained similar throughout the study, ranging from 5.3 to 7.3 percent for in-hospital mortality and from 7.8 to 10.9 percent for one-year mortality. They attributed this to more STEMI patients presenting with comorbid heart failure as the study progressed, demonstrating that clinicians are increasingly performing PCI in more severe cases.
Notably, more patients had heart failure upon admission as the study progressed, but fewer developed in-hospital heart failure—either new-onset or persistent HF symptoms—immediately following PCI.
“The increasing frequency of patients with HF at admission imply that pPCI teams are now more willing to treat higher-risk patients and have, at the same time, been able to achieve shorter FTD times,” Chan and colleagues wrote. “Moreover, with the reduction of FTD, there was an increase in the proportion of patients presenting with acute HF whose HF status improved after admission, as well as a decrease in the proportion of patients with worsening HF status after admission, suggesting that reductions in FTD mitigate the risks of HF post-pPCI.”
The authors noted analyses from other national databases also support an association between reperfusion time and mortality at six to 12 months.
“While none of these studies, including ours, can establish a causal link between FTD and late mortality because of their observational nature, they collectively represent data from four independent healthcare systems that support this epidemiological association,” they wrote. “Our study … reaffirmed that mortality benefits from a shortened FTD may not be demonstrated on a population level because of worsening risk profile, but this relationship is clearly demonstrated on the individual patient-specific level.”
Chan et al. said a major limitation of their study was the lack of information on postdischarge care (aside from medications at discharge), which likely influenced late readmission and mortality outcomes.
Daniel joined TriMed’s Chicago editorial team in 2017 as a Cardiovascular Business writer. He previously worked as a writer for daily newspapers in North Dakota and Indiana.