Excluding the first 30 days after primary percutaneous coronary intervention (PCI), patients with ST-segment elevation myocardial infarction (STEMI) are more likely to die of noncardiovascular than cardiovascular causes, according to a Danish study that will be published in the November 18/25, 2014, issue of the Journal of the American College of Cardiology.  

Most Cardiovascular-Related Deaths Occur Within First Month

Within roughly 5 years (13,447 patient-years), 717 patients died. Overall, 62% of deaths (n = 442) were due to cardiovascular causes, while 38.4% (n = 275) were related to noncardiovascular factors. At 30 days, 1 year, and 5 years postprocedure, all-cause mortality rates were 7.9%, 11.4%, and 23.3% and cardiovascular mortality rates were 7.3%, 8.4%, and 13.8%, respectively. When death was assessed by time frame, 64.8% of mortality that occurred 30 days or more after PCI was noncardiovascular related. Importantly, beyond 1 month post-PCI, the annual cardiac mortality rate increased by < 1.5%.

In the first 30 days, the most common causes of death were cardiogenic shock, anoxic brain damage, and malignant arrhythmia. Reinfarction and cerebrovascular diseases were the main reasons for death from 30 days to 1 year, and after 1 year, congestive heart failure, pneumonia/acute respiratory insufficiency, sudden cardiac death, and especially cancer/other malignancies were responsible for most deaths.  

On multivariate analysis, low TIMI flow, diabetes, history of heart failure, and other factors were prognostic of death (table 1).

Results Support Adjusting Resources, Research

Dr. Kelbæk and colleagues say that the study’s “findings encourage concentration of resources for prevention and treatment of cardiac complications primarily in the early phase of [a] STEMI.”

Though they were unable to determine if the low rate of post-PCI cardiovascular mortality was because of secondary prevention programs, “cardiac rehabilitation programs probably play a role,” the authors say.

In an email with TCTMD, Sunil V. Rao, MD, of Duke University Medical Center (Durham, NC), said that the “data confirm what many of us suspected,” adding, “[W]e tend to think of patients with STEMI who get successful primary PCI as having ‘dodged a bullet,’ but it seems clear that there are bullets coming from different guns—early on its cardiac mortality, but later on its noncardiac.” 

As a result, Dr. Rao suggested that clinical research should take into consideration that “cardiovascular strategies designed to improve outcomes in STEMI may have less of an effect after 30 days.”

Likewise, the study authors say large studies of “risk factor interventions to improve outcomes among survivors of STEMI must focus on noncardiac causes of death.”

Actual ‘Long-term’ Outcomes Studies Difficult

In an editorial accompanying the study, Mark A. Hlatky, MD, of the Stanford University School of Medicine (Stanford, CA), says the Danish data are important because long-term follow-up of patients is time consuming and expensive in countries such as the United States, which lack centralized, systematic patient databases. Additionally, he says that even though linking trial data with national records may be “conceptually simple,” its practice is not easy in the United States.

The US healthcare system “is fragmented, with multiple payers; many patients are uninsured; Americans are obsessed with privacy and distrust the government and large corporations; and regulations designed to protect participants in high-risk clinical interventions have been applied indiscriminately to low-risk research studies,” Dr. Hlatky explains. 

Furthermore, “research sponsors want results quickly; commercial sponsors want to have their products approved without delay; and even the National Institutes of Health wants its investments in research to have tangible results soon,” Dr. Hlatky states. Such barriers lead to “length of follow-up [that] may be a few weeks at most, and a year of follow-up is often considered ‘long-term.’”

Source:
1. Pederson F, Butrymovich V, Kelbæk H, et al. Short- and long-term cause of death in patients treated with primary PCI for STEMI. J Am Coll Cardiol. 2014;64:2101-2108.
2. Hlatky MA. A long-term perspective on short-term outcomes [editorial]. J Am Coll Cardiol. 2014;64:2109-2110.

Disclosures:

• This study was funded by the Research Fund at the Department of Cardiology, Rigshospitalet, University of Copenhagen.
• Drs. Hlatky, Kelbæk, and Rao report no relevant conflicts of interest. 

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