PCI Plus Extracorporeal Oxygenation Improves Outcomes After Cardiac Arrest

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Patients with acute coronary syndromes (ACS) who experience cardiac arrest and are unresponsive to conventional cardiopulmonary resuscitation (CPR) may benefit more from extracorporeal membrane oxygenation (ECMO) when percutaneous coronary intervention (PCI) is added to the mix. The findings, from a retrospective study, were published online August 16, 2012, ahead of print in Circulation.

Eisuke Kagawa, MD, of Hiroshima City Asa Hospital (Hiroshima, Japan), and colleagues reviewed data on 86 patients with cardiac arrest who were thought to have ACS based on symptoms and diagnostic test results. All were unresponsive to CPR and therefore given rapid-response ECMO, which provides temporary perfusion prior to return of spontaneous heartbeat. Patients were treated between January 2004 and May 2011.

Intra-arrest PCI was attempted in 61 patients (71%) and successful 90% of the time. Compared with ECMO alone, ECMO plus PCI was associated with better survival and return of spontaneous heartbeat as well as other improvements (table 1).

Table 1. Clinical Outcomes

The researchers also looked at whether 30-day survival was associated with baseline or treatment factors. Compared with those who died, patients who survived were less likely to have experienced out-of-hospital vs. in-hospital cardiac arrest as their index event (58% vs. 28%; P = 0.01), to have subsequently undergone intra-arrest PCI (88% vs. 70%; P = 0.04), and to have shorter median time intervals from collapse to initiation of ECMO (40 minutes vs. 54 minutes; P = 0.002).

In an e-mail communication with TCTMD, Dr. Kagawa said that while the findings clearly showed better return to spontaneous heartbeat after PCI, the benefits of treatment may extend beyond cardiac conditions to others such as ischemic brain injury. “ECMO could provide [temporary] circulatory support [to] prevent ischemic injury,” he explained. “Mechanical chest compression may be [an] alternative method[, but] we believe that veno-arterial ECMO is superior.”

In terms of potential drawbacks to attempting PCI in this context, Dr. Kagawa noted that though a successful procedure may improve the return of spontaneous circulation, ischemic brain injury could still be severe in cardiac arrest patients. Such patients cannot “return to their former lifestyles,” he said, cautioning, “If we do not select appropriate patients, we [could leave some] in a vegetative state.”

Dr. Kagawa reported that, in Japan, ECMO is widely available and familiar to both cardiologists and emergency physicians. He and his colleagues are planning a prospective study, but ethical concerns prohibit a randomized trial of PCI vs. no PCI for this indication, he noted.

Data Do Not Make the Case

In a telephone interview with TCTMD, however, Thomas D. Stuckey, MD, of the LeBauer Cardiovascular Research Foundation (Greensboro, NC), pointed to design issues that limit the study.

In particular, the paper does not clearly define what constitutes a favorable neurological outcome, he noted. Another issue is the possibility of bias, in that physicians might have been more likely to pursue PCI in patients likely to survive. Therapeutic hypothermia, used in 43% of PCI and 24% of non-PCI patients (P = 0.10), could also have influenced outcomes, he suggested.

Moreover, the findings are less relevant to the United States because few clinicians in this country would use ECMO in this manner, Dr. Stuckey added. “If you have an in-hospital cardiac arrest and you’re not being successful with it, that’s usually where it ends, as opposed to every patient being crashed onto ECMO to try to salvage the CPR,” in part because the treatment is not widely available, especially at smaller hospitals.

“I wouldn’t fault them for trying,” Dr. Stuckey said, but without robust 1-year neurologic outcomes, it would be hard to obtain financing for a randomized trial. If such data were forthcoming, “it’s still worth looking into.”

Study Details

Baseline characteristics between those who did and did not undergo PCI were largely similar, though a higher proportion of the PCI group had cardiac arrest that was witnessed and STEMI vs. NSTEMI. The median duration of ECMO was 27 hours with PCI and 10 hours without PCI (P = 0.01). Intra-aortic balloon pump use also was higher in PCI patients at 44% vs. 24% in non-PCI patients (P < 0.001).

The ECMO system consisted of a Terumo EBS centrifugal pump (Terumo, Tokyo, Japan), Capiox-SX membrane oxygenator (Terumo), heat exchanger, and Capiox bypass cannulas (Terumo).

 

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Source:
Kagawa E, Dote K, Kato M, et al. Should we emergently revascularize occluded coronaries for cardiac arrest? Rapid-response extracorporeal membrane oxygenation and intra-arrest percutaneous coronary intervention. Circulation. 2012;Epub ahead of print.

 

 

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