Reperfusion Therapy Type for Heart Attacks Seems Less Important Than Assuring That All Eligible Patients Receive Timely Treatment

New report in the Canadian Journal of Cardiology examines this question

Philadelphia, PA, July 27, 2016

Patients suffering the classic type of heart attack, ST-elevation myocardial infarction (STEMI), are recommended to undergo reperfusion therapy immediately to restore blood flow to the heart. However, not all STEMI patients receive this potentially life-saving treatment. In a study published in the Canadian Journal of Cardiology, researchers found that patients who did not receive reperfusion treatment had a 30-day mortality rate three to four times higher than patients who did. Moreover, the type of hospital where the patient initially presented also made a significant difference.

STEMI is typically treated with either coronary angioplasty (primary percutaneous coronary intervention [PPCI]) to dislodge the clot and widen the narrowed coronary artery or fibrinolysis with chemicals to break down the clot. These reperfusion therapies restore normal blood flow and can increase chances of survival. For these therapies to work, they should be administered quickly – the standard of care is within 90 minutes for PPCI and 30 minutes for fibrinolysis.

Given the superiority of PPCI in randomized controlled trials, a reasonable question is whether more PPCI centers are required.  The authors address this question by characterizing the participating hospital centers as 1) dedicated PPCI centers that always treat STEMI patients with PPCI; 2) fibrinolysis centers that treat with only fibrinolysis because they are located remote from PPCI centers; 3) transfer centers near PPCI centers that exclusively transfer their patients for PPCI; and 4) “mixed centers,” also generally more remote from PPCI facilities, that treat some of their STEMI patients with fibrinolysis and transfer others for PPCI.

Investigators examined the records of over 3,700 STEMI patients admitted to all 82 Quebec acute care hospitals, and found that more than 2,900 patients received reperfusion treatment (81% PPCI, 19% fibrinolysis), while more than 800 patients (21.8%) did not. Mortality did not differ among reperfused patients regardless of which of the four types of centers initially received the patient and despite treatment delays which were particularly long for patients transferred for PPCI from mixed centers. However, when mortality of ALL patients, both reperfused and non-reperfused, was examined, the mortality in mixed treatment centers was statistically greater than in the other centers.

“Prognosis is better if these interventions can be performed with minimal delay. Studies have extensively investigated and compared these treatments, focusing on time to treatment and how to improve it. But a substantial number of patients with STEMI do not receive reperfusion treatment at all for various reasons and their likelihood of death is significantly higher,” noted lead investigator Laurie J. Lambert, PhD, of the Cardiovascular Evaluation Unit, Institut National d’Excellence en Santé et en Services Sociaux (INESSS), Montreal, Quebec, Canada.

Dr. Lambert explained the significance of their observations as follows: “Some studies have obtained puzzling findings suggesting that treatment delays may not matter so much in patients treated with PPCI.  Our observations suggest that patients transferred long distances for PPCI tend to be at lower risk and have relatively good outcomes by virtue of their low baseline risk, even if overly long treatment delays occur. However, the fate of higher risk patients who have not received reperfusion treatment may go undocumented and unappreciated. Attention needs to be brought to these higher risk patients, and better ways found to improve their outcome.”

Examining the profiles and outcomes of all patients, and not only those receiving reperfusion treatment, may substantially improve patient outcomes by identifying important gaps in treatment and reducing to a minimum the proportion of STEMI patients not receiving reperfusion treatment. This study suggests that in the real world receiving timely reperfusion therapy is more important than which particular modality is utilized.

In an accompanying editorial, Rabih Azar, MD, MPH, of the Hotel Dieu de France Hospital and the St. Joseph University Faculty of Medicine (Beirut, Lebanon), and David Waters, MD, of the San Francisco General Hospital and the University of California San Francisco, commented that, “This study has important clinical and public health implications. As the authors have mentioned, rather than increasing the number of facilities with on-site PPCI, the functioning of the health care system should be improved. Two major targets for intervention are the number of patients who get reperfusion therapy and the delay of such therapy. Transfer networks should be revised and improved in order to facilitate and accelerate transfers. Mixed centers where PPCI was almost always delayed while fibrinolysis was given promptly could be transformed into fibrinolysis centers.”

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Notes for editors
"Outcomes of Patients with ST-Elevation Myocardial Infarction Receiving and Not Receiving Reperfusion Therapy: The Importance of Examining All Patients," by Laurie J. Lambert, PhD, James M. Brophy, MD, PhD, Normand Racine, MD, Stéphane Rinfret, MD, Philippe L. L'Allier, MD, Kevin A. Brown, PhD, Lucy J. Boothroyd, PhD, Dave Ross, MD, Eli Segal, MD, Simon Kouz, MD, Sébastien Maire, MD, Richard Harvey, MD, Abbas Kezouh, PhD, James Nasmith, MD, and Peter Bogaty, MD (doi: 10.1016/j.cjca.2016.02.073). It appears in Canadian Journal of Cardiology, (2016), published by Elsevier.

Author contact for interviews: Véronique Baril at +1 418 455 1044, +1 514 873 2563, ext 21216, or veronique.baril@inesss.qc.ca.

"Editorial: Performance Deficiencies in the Treatment of ST-Elevation Myocardial Infarction in Quebec- ‘Tis but a part we see, and not a whole," by Rabih Raymond Azar, MD, MPH, Zena Kadri, MD, and David Waters, MD (doi: 10.1016/j.cjca.2016.04.016). It appears in Canadian Journal of Cardiology, (2016), published by Elsevier.

Author contact for interviews: Rabih Azar, MD, MPH, FACC. Chief of Cardiology; Hotel Dieu de France Hospital, Beirut, Lebanon at +961 3 590 999 or razar@usj.edu.lb, razarmd@hotmail.com

Full text of this article and editorial is available to credentialed journalists upon request. Contact Eileen Leahy at +1 732 238 3628or cjcmedia@elsevier.com to obtain copies.

About The Canadian Journal of Cardiology
The Canadian Journal of Cardiology is the official journal of the Canadian Cardiovascular Society. It is a vehicle for the international dissemination of new knowledge in cardiology and cardiovascular science, particularly serving as a major venue for the results of Canadian cardiovascular research and Society guidelines. The journal publishes original reports of clinical and basic research relevant to cardiovascular medicine as well as editorials, review articles, case reports, and papers on health outcomes, policy research, ethics, medical history, and political issues affecting practice.

About the Editor-in-Chief
Editor-in-Chief Stanley Nattel, MD, is Paul-David Chair in Cardiovascular Electrophysiology and Professor of Medicine at the University of Montreal and Director of the Electrophysiology Research Program at the Montreal Heart Institute Research Center.

About the Canadian Cardiovascular Society
The Canadian Cardiovascular Society is the professional association for Canadian cardiovascular physicians and scientists working to promote cardiovascular health and care through knowledge translation, professional development, and leadership in health policy. The CCS provides programs and services to its 1900+ members and others in the cardiovascular community, including guidelines for cardiovascular care, the annual Canadian Cardiovascular Congress, and, with the Canadian Cardiovascular Academy, programs for trainees. More information about the CCS and its activities can be found at www.ccs.ca.

About Elsevier
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Media contact
Eileen Leahy
Elsevier
+1 732 238 3628
cjcmedia@elsevier.com