Optimal STEMI Outcomes Demand a Focus Beyond Door-to-Balloon Time

Study shows incremental value from guideline-directed medical therapy and transradial access

A comprehensive systems-based strategy for acute management of ST-segment elevation myocardial infarction (STEMI) improves outcomes compared with a singular focus on door-to-balloon time, according to new research from a team of Cleveland Clinic cardiology and emergency medicine investigators.

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The study, published in Circulation: Cardiovascular Interventions, evaluated the contributions of guideline-directed medical therapy and transradial primary percutaneous coronary intervention (PCI), as well as prompt door-to-balloon time, and found that each component offers incremental outcome improvements.

“This study indicates that it’s time to move beyond focusing solely on door-to-balloon time for providing quality acute STEMI care,” says the study’s corresponding author, Cleveland Clinic cardiologist Umesh Khot, MD. “We found that the best approach is to consistently achieve a range of STEMI care best practices.”

Context: Door-to-balloon time has fallen while death rates haven’t

Door-to-balloon time has been the focus of intense efforts to improve STEMI outcomes for the past two decades via local and national quality initiatives. The Centers for Medicare & Medicaid Services publicly reports it as a hospital performance measure. As a result, door-to-balloon time has dramatically improved nationally, but in-hospital mortality from STEMI in the U.S. has largely stayed the same at about 5 percent.

“Randomized trials of STEMI patients have found improved outcomes from prompt guideline-directed medical therapy and transradial primary PCI,” observes co-author Samir Kapadia, MD, Cleveland Clinic’s Section Head of Interventional Cardiology, “but the incremental prognostic value of each intervention is unknown, and they have not been included in many STEMI quality improvement initiatives.”

Study design

The new study assessed 1,272 consecutive patients with STEMI treated with PCI at Cleveland Clinic from January 2011 through December 2016. Treatment data and outcomes were taken from the medical record and from follow-up phone calls to patients if needed. Survival status at 30 days was ascertained in 98.7 percent of the study population.

STEMI care metrics were defined as the following:

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  • Guideline-directed medical therapy: Administration of aspirin, a P2Y12 inhibitor, and unfractionated or low-molecular weight heparin or bivalirudin before arterial sheath insertion for PCI
  • Transradial primary PCI: Use of the radial artery without crossover to femoral access
  • Door-to-balloon time achievement: < 90 minutes for primary emergency department or in-hospital STEMI, or < 120 minutes for interhospital transfers

Findings: Incremental value from each metric

Among the 1,272 STEMI cases managed during the study period, STEMI care metrics were achieved at the following rates:

  • Zero metrics in 7.1 percent of cases
  • One metric in 24.1 percent
  • Two metrics in 43.8 percent
  • Three metrics in 25.1 percent

Notably, 30-day mortality improved incrementally with the number of metrics achieved, as follows:

  • 6 percent with zero metrics
  • 6 percent with one metric
  • 6 percent with two metrics
  • 2 percent with three metrics

After adjustment for known clinical predictors of STEMI in-hospital mortality, achieving two or more metrics was associated with a significant 61 percent reduction of in-hospital mortality (odds ratio = 0.39; 95% CI, 0.16-0.96; P = 0.041).

Increasing achievement of metrics was also found to have a graded association with reduced rates of bleeding, cardiogenic shock, reduced ejection fraction, cardiovascular mortality and all-cause mortality.

Each metric yielded incremental prognostic value in modeling the risk of in-hospital death when considered sequentially in the order that they were delivered clinically.

Patients with zero metrics were more likely to be women, to have in-hospital STEMI presentation and to have higher rates of major comorbidities at baseline.

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Drs. Khot and Kapadia note that although door-to-balloon time has received nationwide attention and improvement, obstacles need to be overcome for adopting the other metrics.

Currently, strategies to standardize the use of prompt guideline-directed medical therapy for STEMI are lacking. A previous Cleveland Clinic study on the same data set (J Am Coll Cardiol. 2018;71:2122-2132) found that the use of a “STEMI Safe Handoff Checklist” improved the rate of guideline-directed medical therapy use and reduced outcome disparities between men and women.

Hospitals also should strive to standardize the adoption and use of transradial primary PCI as the favored approach in STEMI, advises Dr. Kapadia, who notes that it was the metric least likely to be achieved in this study. He also cites a 2017 report that the rate of its adoption is less than 25 percent, based on the NCDR CathPCI Registry.

Dr. Khot acknowledges that STEMI is a highly complex clinical event, with patients having a diversity of presentations and comorbidities, which may prompt some clinicians to resist adopting what they see as a “cookbook” approach. But he argues that the opposite should be true. “The variability of this condition makes it imperative that a consistent strategy be adopted that encompasses the range of proven management approaches,” he says. “Multifaceted, evidence-based STEMI care offers the opportunity for dramatically improving STEMI outcomes.”