Hurdles Remain in Shortening Reperfusion Times for Transferred STEMI Patients

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For patients with ST-segment elevation myocardial infarction (STEMI) initially presenting at hospitals without percutaneous coronary intervention (PCI), achieving guideline-based reperfusion goals remains difficult, according to a study published online August 7, 2012, ahead of print in Circulation: Cardiovascular Interventions. However, transport via helicopter might not be the answer.

Until recently, American College of Cardiology/American Heart Association guidelines advised that PCI be performed within 90 minutes of initial presentation, though in 2011 the acceptable window was expanded to 120 minutes from first medical contact to device in STEMI patients needing transfer.

Daniel Muñoz, MD, MPA, of Duke University Medical Center (Durham, NC), and colleagues looked at transfer and door-to-device times for 1,537 STEMI patients transported from 98 non-PCI hospitals to 21 PCI hospitals in North Carolina between July 2008 and December 2009. All the centers had implemented standardized protocols for optimizing reperfusion times instituted by the Regional Approach to Cardiovascular Emergencies (RACE) project.

Anticipated drive times were established for the trip from each non-PCI center to the nearest PCI center using a conventional online navigation tool. Each patient presentation to a non-PCI center subsequently fell into 1 of 3 categories based on the anticipated drive time (short: ≤ 30 minutes; medium: 31-45 minutes; and long: > 45 minutes) as well as into 1 of 2 categories based on mode of transport (ground or air).

Helicopter Transfer Not Always Faster

Approximately half of patients whose ground transfers were predicted to be short met the 90-minute guideline goal. However, less than 20% of patients in the medium and long transport time groups met that goal, regardless of whether transfer occurred by air or by ground. For the most distant air transfers, only about 35% achieved door-to-device times within 120 minutes (table 1).

Table 1. Median Door-to-Device Times

Anticipated Drive Time

Ground Transport

Air Transport

Short

93 minutes

Medium

117 minutes

125 minutes

Long

121 minutes

138 minutes


Once patient transport was underway, trips by air tended to occur faster than those by ground (21 minutes vs. 42 minutes in the medium group; 34 minutes vs. 52 minutes in the long group).

However, median door-in door-out times at the initial non-PCI facilities were lengthier for air transfers (63 minutes for the medium group; 72 minutes for the long group) than for ground transfers (38 minutes for the short group; 43 minutes for the medium group; 40 minutes for the long group).

Starting the Conversation

In a telephone interview with TCTMD, Dr. Muñoz said that “one generally thinks of air transport as being faster, which it is. Once the wheels are up a helicopter will go faster than an ambulance, but door-to-device time has numerous elements and the actual transport is just one of them.”

Since every regional system has unique geographical characteristics and resource availability, he explained, both the RACE program and the study itself were not designed to dictate policy but rather to serve as “an analytical template” for other hospital networks to begin asking questions that help to improve key elements of the transfer process and ultimately lead to better STEMI care.

“As an example, not every hospital has a helicopter on site,” Dr. Muñoz observed. “Therefore, to engineer an air transfer, non-PCI centers oftentimes must wait for a helicopter to be sent out to them for the patient pickup.

He emphasized the observational nature of the study, stressing that ground transport is not necessarily better but that its association with shorter treatment times merely raises questions. “There will always be an important role for air transport. The key is figuring out when it’s best and how best to make use of it,” he said

“[S]ignificant challenges remain in achieving guideline based reperfusion goals for STEMI patients even in a well-developed system like North Carolina,” Dr. Muñoz concluded. “What we hope is that the RACE program will inspire regions around the country to self-analyze and ask the key question of how we can provide the highest quality of care possible to STEMI patients.”

 


Source:
Muñoz D, Roettig ML, Monk L, et al. Transport time and care processes for patients transferred with ST-segment–elevation myocardial infarction: The reperfusion in acute myocardial infarction in Carolina emergency rooms experience. Circ Cardiovasc Interv. 2012:Epub ahead of print.

 

 

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Disclosures
  • Dr. Muñoz reports no relevant conflicts of interest.

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