In STEMI Transfer, Less Time at Referral Hospital Means Better Outcome

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Patients with ST-segment elevation myocardial infarction (STEMI) who require a transfer to a hospital capable of performing primary percutaneous coronary intervention (PCI) have improved outcomes when the time from arrival to departure at the initial center is less than 30 minutes, researchers report in the June 22/29, 2011, issue of the Journal of the American Medical Association. Unfortunately, the study also found that only about 10% of patients are transferred within that time frame.

Tracy Y. Wang, MD, MHS, MSc, of Duke University Medical Center (Durham, NC), and colleagues examined data from 14,821 STEMI patients transferred to 298 STEMI receiving centers for primary PCI in the ACTION Registry–Get With the Guidelines between January 2007 and March 2010. The study gauged door-in to door-out time, defined as the time from arrival to discharge at the initial referral hospital.

Overall, the median door-in/door-out time was 68 minutes (interquartile range, 43-120 minutes), with only 11% of patients in and out within 30 minutes.

Predictors of Delay

Patients who spent more than 30 minutes at the referral hospital were more likely to be older, female, have off-hours presentation, and nonemergency medical services transport to the first facility. Multivariable analysis showed these factors to be independent predictors of extended time at the referral center, although comorbid conditions and hemodynamic instability also contributed to delay (table 1).

Table 1. Factors Associated with Prolonged Door-In to Door-Out Times

Among patients with door in/door out times greater than 30 minutes or greater than 60 minutes, only 0.6% and 0.9%, respectively, had an absolute contraindication to fibrinolysis, which is the preferred reperfusion strategy for STEMI when access to timely primary PCI is not a viable option.

The median overall door-to-balloon (D2B) time from first hospital presentation to second hospital PCI was 120 minutes. Only 19% of transferred patients achieved the recommended D2B time of 90 minutes or less. However, patients with an in and out time of 30 minutes or less were significantly more likely than those with longer times to have an overall D2B time of 90 minutes or less (60% vs. 13%; P < 0.001). In addition, patients with an in and out time greater than 30 minutes had longer second hospital arrival to balloon time compared with those who had an in and out time of 30 minutes or less (median 31 vs. 26 minutes; P < 0.001).

After primary PCI, in-hospital mortality was significantly higher for patients with in and out times longer than 30 minutes vs. those who were in and out in less time (5.5% vs. 2.7%; P < 0.001). The difference persisted after adjusting for baseline characteristics and presenting features (adjusted OR 1.56; 95% CI 1.15-2.21; P = 0.004).

“Our study shows that while there has been a significant downward secular trend in [door-in to door-out] time, only 1 in 10 patients achieved a . . . time of 30 minutes or less at the STEMI referral hospital,” Dr. Wang and colleagues write. “In fact, more than one-third of patients had a [door-in to door-out] time greater than 90 minutes and more than 58% had a [door-in to door-out] time greater than 60 minutes, rendering an overall [D2B] time of 90 minutes or less realistically unachievable.”

STEMI Networks Crucial to Timely Transfer

In a telephone interview with TCTMD, Dr. Wang noted that door-in to door-out time is a clinical metric that came out of the 2008 ACC/AHA Performance Measures for STEMI. Its role in assessing health care system delays, she said, is an increasingly crucial area for study and improvement.

“[It’s] important because in order for transfer patients to have the D2B time of 90 minutes or less, a lot of things have to happen when they arrive at the first hospital,” she said. “You have time spent at that hospital, you have the amount of time spent traveling to the next hospital, and then of course the amount of time it takes them to get to the actual PCI once they get there. Our study is the first to show that getting patients out [of the first hospital] earlier does improve outcomes. But [early transfer] was not achieved in the majority of the cases.”

Dr. Wang said the study underlines the importance of STEMI networks within regional areas with agreed-on protocols (eg, not repeating EKGs or lab work at the second hospital). In addition, key components of expediting door-in to door-out time include:

• Early diagnosis
• Ready transportation
• Efficient communication

“There are a lot of details that go into this, but they are important details, and if they were prespecified and decided on within a network of hospitals, it would significantly shorten door-in to door-out times,” Dr. Wang said.

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Source:
Wang TY, Nallamothu BK, Krumholz HM, et al. Association of door-in to door-out time with reperfusion delays and outcomes among patients transferred for primary percutaneous coronary intervention. JAMA. 2011;305:2540-2547.

 

 

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