LECTURES

Ottawa Heart Institute Alumni Spring Lecture
April 26, 2005

"The Ottawa STEMI Program"
Dr. Marino Labinaz
Director, Cardiac Catheterization Laboratory and Interventional Cardiology
University of Ottawa Heart Institute

The very informative lecture on STEMI was one in a continuing series sponsored by the Alumni. It was held in the Foustanellas Auditorium, April 26.

Dr. Labinaz opened his presentation with a few definitions and an explanation of the particular heart attack (myocardial infarction) that is called a "STEMI". This short form is an acronym for ST segment Elevation Myocardial Infarction. It is identified on an electrocardiogram (ECG) as elevation of the "ST segment" (a particular blip on the trace,) which indicates an arterial blockage that can result in severe damage to the heart muscle (myocardium) if blood flow is not restored fairly soon after the onset of pain.

Reperfusion, (restoring blood flow,) the salvaging of as much of the myocardium as possible and the restoration of the contractile function of the heart chambers, is best achieved by PCI (Percutaneous Coronary Intervention,) commonly known as angioplasty. This is the mechanical enlargement of a narrowed coronary artery, generally involving the insertion of a stent. Drugs that dissolve clot in blood vessels (fibrinolytics, also known as clot-busters or "lytics",) can also be used for reperfusion but they are not as effective as PCI.

When a STEMI is diagnosed, the objective is to restore heart function as quickly and as fully as possible. The goal is to achieve reperfusion within 60 to 90 minutes to minimize heart muscle damage. While this is the optimal time, beneficial results can result up to 12 hours after the onset of symptoms. Primary PCI, i.e., immediately performing a PCI, is the best treatment of a STEMI. When the patient cannot be taken to a catheterization laboratory quickly enough, lytics will be administered. The application of lytics prior to a planned PCI is known as a facilitated PCI.

To bring persons experiencing STEMI to the Heart Institute so that a primary PCI can be done with minimum delay, the Ottawa Code STEMI program was set up. When paramedics respond to a 911 call and find a person experiencing severe chest pain, an ECG is taken on the spot. If a STEMI is diagnosed, the paramedics notify the Heart Institute and give an estimate of the time of arrival. A "Code STEMI" is broadcast on the intercom to alert the staff. The paramedics take the patient directly to the catheterization lab where a team is waiting. In off hours, the Communications Centre notifies the on-call interventional cardiologist and cath lab team.

Dr. Labinaz described the coordination among the various organizations in Ottawa and praised the willingness of the practitioners to participate, all of which was essential if Code STEMI was to be a success.

First, hospitals in the City of Ottawa agreed that the paramedics, having diagnosed a STEMI, could go directly to the Heart Institute, rather than to the nearest ER, as required by Ontario regulations. Emergency Medical Services (EMS) supported the training of paramedics to use ECGs to diagnose a STEMI. Finally, to make Code STEMI available on a 24-hour, seven-days-a-week basis, interventionists and the cath lab teams agreed to be on call.

The evolution of treatment of heart attack patients since the development of coronary care units in the 1970s, and the introduction of clot-busters reduced the mortality rate in the 30 days following an incident from about 25%, to 8-10%. Now, with PCI, the 30-day mortality rate is 2-3%. When the patient can be transported to the Heart Institute within 60 to 90 minutes of onset, primary PCI is the optimum treatment.

Within the city, the rapid response of the paramedics has been a significant factor in achieving the timing targets. (Incidentally, a 911 call is strongly recommended rather than self-transport to a hospital ER because of direct transport to the Heart Institute when a STEMI is diagnosed.)

The median time intervals for Code STEMI were:

• symptom onset to dialing 911: 58 minutes
• 911 to ambulance arrival: 9 minutes
• ambulance arrival to ECG: 8 minutes
• ECG to hospital arrival: 23 minutes
• hospital arrival to balloon (opening of the vessel): 63 minutes

A study conducted at the Ottawa Heart Institute, the CAPITALAMI, concluded that:

• a strategy of lytics plus immediate PCI for high risk STEMI patients is superior to lytics alone;
• lytics followed by PCI is relatively safe, i.e. not associated with excessive bleeding complications;
• all high risk STEMI patients treated with lytics should be considered for immediate PCI.

The success in implementing the Heart Institute's STEMI program has been due to the methodical approach taken. Dr. Labinaz noted that Primary PCI was implemented for:

• all STEMI diagnosed at the Civic ER in 2003;
• paramedic diagnosis and direct transfer to the Heart Institute in July 2004;
• diagnosis at the Queensway Carleton, Ottawa General and Montfort ERs on May 2, 2005; and
• for elsewhere in the Champlain District, it is still a work in progress.

He sees the challenge in the region being:

• the development of prehospital strategies in the "outer" region, (lytics in the field, facilitated PCI, early patient triage);
• primary PCI as the standard of care in the "inner" city of Ottawa; and
• a key role for paramedics.

Dr. Labinaz's recommended state for STEMI-related cardiac care:

• development of a regional MI system, involving the Heart Institute, the referring acute-care hospitals and EMS, to provide efficient, effective and quality patient management for STEMI patients from assessment through to post-MI care and cardiac rehabilitation; and
• that primary PCI for STEMI patients, presenting within 12 hours of symptom onset, be the preferred therapy for:
• • all eligible patients in the City of Ottawa, with a target door to balloon time of less than 90 minutes;
  • all eligible patients who can be transferred from an acute care hospital to a primary PCI center, with a door to balloon time of less than 90 minutes;
  • all patients who have contraindications to lytics therapy, regardless of distance, as long as the procedure can be performed within 12 hours of onset;
  • patients who present after 12 hours of symptom onset are to be managed on a case by case basis.

[The foregoing was prepared by Alumni President Denny Doucette, and reviewed in draft by Dr. Labinaz.]

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