Door-to-Balloon

balloon

When I started in EMS, it was drilled into me. I had ten minutes on scene for trauma and 20 minutes for medicals. If I took longer, I had to explain why. If I did it quicker, all was good.

Evidence – based medicine wasn’t in our vocabulary then. We believed whole-heartedly in the golden hour of trauma. Times have changed. For trauma, studies have shown the golden hour has no scientific basis and that EMS time intervals have little to no effect on outcomes in trauma.

But what about medicals, and in particular what about ST-elevation myocardial infarctions(STEMIs)? The American Heart Association says that for patients having ST-Elevation MIs, who go to the cath lab to have their occlusions cleared, the systems goal should be a first medical contact–to-balloon time within 90 minutes.*

So 90 minutes is the goal? But is there anything magic about the 90 minute time? And how much better or worse does someone do if they get to the cath lab earlier or later than the 90 minutes?

A recent study in the British Medical Journal, Association of door-to-balloon time and mortality in patients admitted to hospital with ST elevation myocardial infarction: national cohort study., asks: Is mortality higher with successively longer times to treatment? And does mortality plateau after two or more hours of delay?

To answer this, the investigators analyzed the National Cardiovascular Data Bank, sponsored by the American College of Cardiology, which collects standardized data from 600 participating cath labs.

They hypothesized that any increase in door-to-balloon time would be associated with increased mortality and that this mortality risk would persist irrespective of the length of the delay in treatment.

For a study sample they looked at the records for 2005-2006, counting the patients presenting within 12 hours of symptom onset, who had lab and ECG evidence of STEMI, and who underwent the cath procedure.

They excluded transferred patients, patients who received fibrinolytic therapy first, patients under 18 or over 99, and patients at facilities that did less than 5 procedures a year.

They further excluded patients who had missing times, who had door-to-balloon times of less than 15 minutes (excluded due to possible incorrectly coded times) and excluded patients with door-to-balloon times of > 6 Hours (excluded because PCI was presumably not the primary reperfusion strategy). This left a total of 43,801 patients.

In the study the median door-to-balloon time was 83 Minutes. 57.9% were treated within 90 Minutes.

Women, nonwhites, older patients, and patients with comorbidities had proportionally longer door-to-balloon times. Patients with shorter door-to-balloon times were treated between 8AM and 4 PM, at urban hospitals, and had lower incidences of cardiogenic shock.

Mortality was 4.6%. Patients who died had a 14 minute longer median door-to-balloon time. Mortality was 2.8% for patients with 30 minutes, 9.8% for door-to-balloon times of 240. When patients with shock were excluded, longer door-to-balloon times continued to be associated with mortality.

When plotted out on a graph, there was a steadily rising minute by minute mortality curve.

The results are pretty easily explained: Patients with longer door-to-balloon times will experience longer periods of ischemia and more necrosis than patients with shorter time to treatment.

The clinical implications are also clear:

“Any minute of delay is associated with an increased risk of mortality.”

“There is no ‘floor’ to the mortality reduction that can be achieved by reducing time to treatment.”

Reducing D2B from 90 to 60 minutes could reduce mortality from 4.3% to 3.5%.

Rather than settling for 90 minutes as the standard, the standard should be “As soon as possible.”

As far as limitations, the study did not assess time from onset of symptoms to arrival at hospital, nor did the study assess door-to-balloon and subsequent mortality at 30 days, 1 year. It did not examine morbidity.

The bottom line:

Door-to-balloon time is associated with mortality.

Any delay in door-to-balloon time is associated with increased mortality.

My thoughts;

This is an excellent study with a large patient sample. I cannot help but think if mortality can be improved by such a great percent, the morbity improvement must be even more substantial.

Here’s what I will try to do and what I will tell other medics to do:

Cast a wide net with your 12-lead. Get a clear 12-lead as soon as possible.

Once you recognize a STEMI, call the hospital right away so they have all the necessary equipment and personnel ready to go as you hit the doors.

Get going. Don’t dawdle on scene. Don’t wait for the patient’s daughter to arrive. Don’t let the patient take his time going about gathering his toothbrush and pajamas. Get on your way. Lights and sirens if needed for traffic, but drive safely.

Do serial 12-leads.

Don’t forget the Aspirin.

* 2007 Focused Update of the ACC/AHA 2004 Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction

9 Comments

  • Great article, Peter. Thanks for taking the time to explain the details of the study and breaking down the data.

    I can’t help but thinking back to a call we ran that was 27 minutes from SYMPTOMS to balloon. The patient quickly activated EMS, we arrived within 5 minutes, quickly hooked up 12-lead WHILE giving ASA and NTG and recognized STEMI within 4 minutes of arrival, immediately notified the receiving hospital within another minute, and within two more were enrt to the hosp with an 8 minute transport time. The rest was accomplished by the cath lab who was ready for our patient quickly after our initial notification.

    My point is this: as quickly as we can make things happen once we are involved, we need to also look at getting involved ASAP as well. As we move into the future of EMS (EMS 2.0) we take on a larger responsibility by becoming more community-based, and educating our future patients on recognition of symptoms and early EMS activation. With a new starting time, we can really hit the ground running as we play beat the clock.

    Again, thanks for an excellent article!

  • CBEMT says:

    Agree 100% Peter. Unfortunately, our local PCI centers are not on the “activating based on EMS report” bandwagon yet. They will not activate without at least a transmitted 12-lead, which few services here have and the ones that do rarely use. “We don’t have time” and “It doesn’t matter” and “They don’t care anyway” are commonly heard.

  • JimmyG, RN says:

    In Contra Costa County (east bay of SF area) we activate on 12 Lead STEMI called from EMS in the field. By the time the bus arrives, the team is ready in the Trauma room (no delays) – Sometimes the Cardiologist calls off the “heart alert” based on the reading of EKG done upon arrival, but the ones that are confirmed have at least 15 minutes off their door to Ballon time. This system works !! – or why do we bother to train Paramedics to do 12 leads ???

  • cna training says:

    nice post. thanks.

  • totwtytr says:

    From my experience the problem with D2B times is within the hospitals, not in the field. Although I like the concept of medics reading ECGs and making at least a preliminary determination of STEMI, the truth is that we are doing it to push slow hospitals to speed up their cath lab process. At least around here where we have more than one PCI hospital.

    The problem is particularly bad during off peak hours when staff has to be called in from home. In those cases the earlier the notification, the better.

    The fly in the ointment is that EMS systems have to ensure that their medics are proficient at reading 12 Leads.

  • newbie says:

    gotta say…ive only been an emt since february, been riding on the bus now though for almost a year, and today i happened to recognize a STEMI before the medic did…im not good at reading 12 leads, etc…but from all your posts, i somehow in the thick of the moment caught a glimpse of the printout and shouted it out. right after i opened my mouth, i hoped to God i was right…medic actually had to look twice. dtb time was 70 minutes i believe, als protocols established about 10 minutes after dispatch. THANK YOU! : )

  • Herb says:

    The trick is coordination between the PCI center, the ED, and EMS. I work in central PA in urban rural setting. Our short transports are 18 miles and 30+ is not unusual. The ED has a STEMI email address. We take a picture with our cell phones and send it. The ED then determines activation of the cath team [max time 30 minutes]. Most of the time we transfer the pt from our litter on to the cath lab table. We have been using this system for 2-3 years now and it works great. Our scene to baloon time is almost always less than 90 minutes and often in the 60-70 minute range.

  • Bruce says:

    From my experience the problem with D2B times is within the hospitals, not in the field. Although I like the concept of medics reading ECGs and making at least a preliminary determination of STEMI, the truth is that we are doing it to push slow hospitals to speed up their cath lab process. At least around here where we have more than one PCI hospital.

    The problem is particularly bad during off peak hours when staff has to be called in from home. In those cases the earlier the notification, the better.

    The fly in the ointment is that EMS systems have to ensure that their medics are proficient at reading 12 Leads.

  • Bruce says:

    gotta say…ive only been an emt since february, been riding on the bus now though for almost a year, and today i happened to recognize a STEMI before the medic did…im not good at reading 12 leads, etc…but from all your posts, i somehow in the thick of the moment caught a glimpse of the printout and shouted it out. right after i opened my mouth, i hoped to God i was right…medic actually had to look twice. dtb time was 70 minutes i believe, als protocols established about 10 minutes after dispatch. THANK YOU! : )

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