FW: [E2B] Door-to-Balloon Time: Even Less Is More

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Subject: [E2B] Door-to-Balloon Time: Even Less Is More

http://www.tctmd.com/show.aspx?id=78644

Door-to-Balloon Time: Even Less Is More

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Key Points:

* Reducing D2B time below 90 minutes continues to reduce mortality

* Shorter D2B time may lessen impact on LV function

* Centers should not be satisfied with meeting guidelines

_____

By C. Holzman

Tuesday, June 02, 2009

Any delay in door-to-balloon (D2B) time for patients with ST-segment elevation

myocardial infarction (STEMI) who are undergoing primary percutaneous coronary

intervention (PCI) increases the risk of death, suggesting that every effort

should be made to surpass the current D2B goal of ≤ 90 minutes, according to a

study published in the May 30, 2009, issue of the British Medical Journal.

Researchers led by Saif S. Rathore, an MD/PhD student at Yale University School

of Medicine (New Haven, CT), determined mortality as a function of D2B time in a

cohort of 43,801 patients from the American College of Cardiology National

Cardiovascular Data Registry who presented with STEMI and underwent primary PCI

within 12 hours of symptom onset.

The median D2B time was 83 minutes (interquartile range 6-109 minutes), with

57.9% of patients treated within 90 minutes. Overall in-hospital mortality was

4.6%.

Multivariable analysis showed that longer D2B times were associated with a

progressively higher adjusted risk of in-hospital mortality (table 1).

Table 1. Estimated In-Hospital Mortality by D2B Time

Time, minutes

Unadjusted Mortality

(95% CI)

Adjusted Mortalitya

(95% CI)

15

2.6% (2.3-2.8)

2.9% (2.8-3.1)

30

2.8% (2.5-3.0)

3.0% (2.9-3.2)

45

3.1% (2.8-3.3)

3.2% (3.1-3.3)

60

3.4% (3.2-3.7)

3.5% (3.4-3.6)

75

3.9% (3.7-4.1)

3.8% (3.7-4.0)

90

4.4% (4.2-4.6)

4.3% (4.2-4.4)

180

8.4% (7.7-9.1)

8.4% (8.2-8.7)

240

9.8% (8.7-11.0)

10.3% (10.0-10.7)

a Adjusted for sex, age, race, findings on presentation, medical history,

procedural characteristics, angiographic findings, and hospital factors.

Earlier studies missed mortality improvements for D2B times < 90 minutes because

they averaged the data into crude 60- or 90-minute increments instead of

analyzing them as independent data points, Mr. Rathore explained in a telephone

interview with TCTMD.

Shaving D2B time to < 90 minutes for three quarters of patients has been the

goal of several major efforts such as the ACC’s D2B Alliance, a D2B reduction

effort within primary PCI hospitals, and the American Heart Association’s

Mission: Lifeline, which focuses on early patient symptom recognition and better

pre-hospital and interhospital systems.

Shrinking D2B Times Is Doable

Much-reduced times are possible and commonly achieved in some settings. “A

center in Italy has an average door-to-balloon time of 20 minutes,†Mr.

Rathore pointed out.

“For years, paramedics, the emergency department, and the cath lab have

[simply] coexisted,†Ivan C. Rokos, MD, of the Geffen School of Medicine

at UCLA (Los Angeles, CA), told TCTMD in a telephone interview. “Now we are

working on coordinating them into 1 seamless STEMI-care provider unit. We have

every reason to believe, based on Mr. Rathore’s paper, that we are improving

mortality.â€

In fact, an analysis of 10 independent regional STEMI receiving networks, led by

Dr. Rokos (Rokos IC. J Am Coll Cardiol Intv. 2009;2:339-346; see related story

“Integrated STEMI†below) showed that these efforts are paying off, with 86%

of D2B times coming in at ≤ 90 minutes.

Efforts at streamlining STEMI care include legislation that will take effect

this summer in North Carolina requiring coordination between EMS agencies and

providers, Granger, MD, of Duke University Medical Center (Durham,

NC), said in a telephone interview with TCTMD. Paramedics will be able to take

ECGs in the field, and if a heart attack in progress is suspected, they will

alert the cath lab to be ready when the patient arrives, potentially saving 30

minutes, he said.

Other types of innovations have also reduced D2B times. For example, at the

Minneapolis Heart Institute, emergency physicians are able to activate the cath

lab, and in some Canadian centers, the patient bypasses the emergency

department, going directly to the cath lab, said Mr. Rathore.

Fast D2B Time May Save Myocardium

While the study’s observational nature does not prove causation, all 3

clinicians emphasized that shorter D2B times would likely result not only in

reduced mortality but in a healthier heart due to less tissue damage. “It

makes sense pathophysiologically,†said Mr. Rathore. “The longer the vessel

is occluded, the farther the necrosis spreads from the area perfused by that

vessel.†Previous studies have shown that “faster opening of the artery in a

heart attack caused by a blocked artery results in better recovery of the heart

muscle,†added Dr. Granger.

“Time has an amazing dose-response curve,†commented Dr. Rokos. “We should

stop thinking of time as a therapeutic variable and start thinking of it as a

therapy.†To illustrate, he related a vignette from a recent AHA statement on

pre-hospital ECGs describing a woman who had presented with a proximal LAD

lesion—or a ‘widow maker’—yet had been discharged with LV function

preserved after a D2B time of just 21 minutes.

_____

Source:

Rathore SS, Curtis JP, Chen J, et al. Association of door-to-balloon time and

mortality in patients admitted to hospital with ST elevation myocardial

infarction: National cohort study. BMJ. 2009;Epub ahead of print.

Disclosures:

* The study was supported in part by grants from the National Institutes of

Health.

* Mr. Rathore and Drs. Rokos and Granger report no relevant conflicts of

interest.

Related Stories:

* Integrated http://www.tctmd.com/show.aspx?id=77738> STEMI Care Networks

Achieve Optimal D2B Times

* D2B Times Improve http://www.tctmd.com/show.aspx?id=77738> Thanks to

Program’s Efforts

* STEMI Patients http://tctmd.com/Show.aspx?id=75736> Benefit from

Pre-Hospital ECGs