Door to Balloon Time: Are We Measuring the Right Thing?

Door to Balloon Time: Are We Measuring the Right Thing?

2016-11-11T19:03:45+00:00

human_heart_bandaid_pc_1600_clr_1770Door-to Balloon (D2B) time is a time measurement that starts with patient arrival to the emergency department (door) and ends when a catheter crosses a culprit lesion in the cardiac cath lab (balloon). The benefit of prompt primary percutaneous coronary intervention over thrombolytic therapy for acute ST elevation myocardial infarction is very well established. Because of this “time is muscle” strategy, the American College of Cardiology (ACC) launched a national Door to Balloon (D2B) initiative in November 2006. The purpose of this was to recommend a D2B time of no more than 90 minutes. Currently, there is quite a bit of effort put into this guideline by cardiology and emergency medicine, but are we measuring the right thing?

What are some proven strategies that do help reduce D2B time? 1

  • 365 surveyed hospitals
STRATEGY MEAN REDUCTION in D2B TIME
ED physician activated the cath lab 8.2 min
Single call activation system to activate the cath lab 13.8 min
Prehospital ECG activation of cath lab 15.4 min
Cath lab team is available within 20 min of being paged 19.3 min
Attending cardiologist always on site 14.6 min
Prompt data feedback between EM and Cardiology staff 8.6 min

Does D2B time decrease significantly if multiple strategies are used? 1

  • 365 surveyed hospitals
  • 0 strategies = avg D2B time 110 min
  • 1 strategy = avg D2B time 100 min
  • 2 strategies = avg D2B time 88 min
  • 3 strategies = avg D2B time 88 min
  • 4 strategies = avg D2B time 79 min

So if the above strategies are evidence based, have been shown to reduce D2B times, and “time is muscle,” then this should be standard of care, right? Currently, D2B times of 90 minutes or less (Class I recommendation) have become a performance measure and the focus of regional/national quality improvement initiatives. More importantly, does this measure reduce morbidity/mortality? Recently, in the September 2013 NEJM 2 a retrospective, observational study looked at this exact question.

How large was this NEJM study?

  • 95,007 patients accounted for 96,738 admissions for primary PCI of STEMI
  • 515 hospitals participating in the CathPCI Registry
  • Conclusion:  The study was very large

How were the D2B times in this study?

  • 2005 – 2006 mean D2B time 83 minutes
  • 2008 – 2009 mean D2B time 67 minutes
  • There was an increase from 59.7% to 83.1% of patients having D2B times ≤90 minutes over the course of the study
  • Conclusion: D2B time decreased over the course of the study

So does lower D2B correlate with decreased mortality?

  • Overall, unadjusted mortality if D2B ≤90 minutes: 4.8% in first year of study
  • Overall, unadjusted mortality if D2B >90 minutes: 4.7% in the last year of the study
  • When these were risk adjusted, there was no statistical difference in mortality
  • Conclusion: No difference in mortality despite improved D2B times

Take Home Message

So despite reductions in D2B times across the nation, we have not impacted 30 day in hospital mortality. Maybe what we should be measuring is symptom onset to balloon time?

1.
Bradley E, Herrin J, Wang Y, et al. Strategies for reducing the door-to-balloon time in acute myocardial infarction. N Engl J Med. 2006;355(22):2308-2320. [PubMed]
2.
Menees D, Peterson E, Wang Y, et al. Door-to-balloon time and mortality among patients undergoing primary PCI. N Engl J Med. 2013;369(10):901-909. [PubMed]

Salim Rezaie, MD

Salim Rezaie, MD

ALiEM Associate Editor
Clinical Assistant Professor of EM and IM
University of Texas Health Science Center at San Antonio
Founder, Editor, Author of R.E.B.E.L. EM and REBEL Reviews
  • Matt Astin

    Good review of the article. It would also be interesting to see if decreased D2B time affects morbidity as well, and by how much. Does getting them to the cath lab sooner decrease hospital and ICU length of stay? What about cardiac rehab costs? This review just proves something that I realized a while back: Some people are going to die, no matter what we do. I think a review of the related morbidity would show us that all of these increased efforts do indeed pay off. By the way, I also agree that symptom onset to ballon time is more accurate. But, that places some of the morbidity/mortality responsibility on the patient. We know we can’t rely on them. 😉

    • Salim R. Rezaie

      Hello Matt,
      Great comment. That was one of the discussion points of the article is that we don’t know how it affects morbidity. It does bring up a great point of, time is muscle and really time starts from symptom onset and not arrival to the emergency department which is a standard we are held to. TY as always for your support and comments. I always find them very thought provoking.

      Salim

  • Michelle

    Just saw that Ryan Radecki also wrote about this on his EMLitOfNote blog summarizing similar points where a seemingly great idea translates to unclear value/impact.

    http://www.emlitofnote.com/2013/09/door-to-balloon-time-flawed-quality.html

    I do have to say though that after our site established a formalized STEMI activation process, it HAS streamlined a lot of logistical hurdles that we encountered EVERY time we wanted to have the patient be cath’d.

  • Chante Karimkhani

    Thanks for a great review of this article Salim. One thing though, I’m confused on the section where you reported the results of the trial. I think that the 2005-2006 mortality of 4.8% compared to the 2008-2009 mortality of 4.7% were for the entire patient population (not just those that had D2B times> or < 90 minutes), correspond to figure 1 in the article. They do report the mortality rates for D2B time in figure 2.

    • Salim R. Rezaie

      Hello Chante,
      TY for taking the time to read the post. So there are a lot of numbers thrown around in the article you are referencing. So let me try and summarize. The first table, Panel A is all comers, the other 3 panels specifically are looking at AMI, cardiogenic shock etc. In all comers the overall, unadjusted mortality (which is what a quoted in the post) does not decrease in this patient population despite having a decrease in D2B times. Remember these are means. The second figure then takes all comers and divides them into those that had D2B times less than 90 and greater than 90 min. Despite the percentage of pts going up with D2B times of <90 min, the mortality still stays the same, but not statistically significant. I hope that clarifies. TY again. 🙂

      Salim

      • Michelle

        Here are the figures 1 and 2 to help clarify, since Disqus let’s us import images.

  • Stephen Smith

    There are many complicating factors. A very important one which was not mentioned in the article and only hinted at in the editorial was this: Approximately 1/3 (36% in the only study that I am aware of that reported this) of STEMI activations have TIMI-3 flow at angiogram. These patients clearly do not benefit from faster door to balloon time and would greatly dilute any beneficial effect (McCabe JM et al. Arch Intern Med. 2012;172:864–71).

    • Salim R. Rezaie

      As always Dr. Smith, always appreciate your input. That is a very important point to take into context when drawing conclusions from this study. For those unfamiliar with TIMI-flow, TIMI-3 flow is normal flow which fills the distal coronary bed completely. Thank you again Dr. Smith.

      Salim