Postcards From the Cutting Edge

Your patient is suffering chest pain that started 20 minutes ago. His pain, which he rates as 8 on a scale of 10, radiates from his substernal chest to his left arm. He complains of nausea and has obvious diaphoresis. You are a few miles away from your local community hospital, but 45 minutes away from an emergency facility with catheterization capability. Where do you go?

Several studies suggest that primary angioplasty is the best choice in this case,^1-3 but is it really?

In acute coronary syndromes, particularly ST-segment-elevation heart attacks, reperfusion of some sort is required, or muscle death will occur. Heart attacks happen when coronary arteries become blocked by clots that have moved into the myocardium. Our primary treatment focuses on providing oxygen to the patient; making the platelets slippery and interfering with the clotting cascade with baby aspirin; and opening the peripheral pipes with nitroglycerin and morphine.

Hospital care has focused on breaking the clot up with thrombolytics or fibrinolytics, or on percutaneous coronary interventions (PCIs) such as stent placement and angioplasty to physically open the arteries and remove atherosclerotic buildup of plaque.

Part of the issue with fibrinolytics is that they chew through clots. These clots may be in the coronary arteries, where we want them broken up-or in other places, such as the stomach (including ulcers) or other parts of the body, from recent trauma. They may also be from insignificant surgeries such as hair plugs.

Another factor in the use of fibrinolytics is time. We have typically used a time frame of six hours to administer fibrinolytics. However, some studies suggest that to be effective, they need to be used much earlier than previously thought.^4,5 In fact, optimal timing may be within 70-120 minutes.^6,7 Earlier field initiation of certain fibrinolytic drug therapies may be indicated.

In one study, patients had a 50% reduction in mortality from early fibrinolytic administration.⁸ This study followed up with its subjects at five years and found that fewer had died in the out-of-hospital fibrinolytic group (25%) than in the hospital fibrinolytic group (36%).⁹

Similarly, it appears that PCIs are best used early as well, and it may be that combining both treatments is even more effective.

Fibrolytics in the Field
Some aggressive EMS systems may be treating heart attack patients with fibrinolytics in the field, even in suburban systems, in the not-too-distant future. One example of this is in a suburb north of Houston, where 21 EMS services, a local air-medical provider and Conroe Regional Medical Center, the local tertiary-care heart center, are aggressively integrating the thrombolytic TPA (tissue plasminogen activator) in the field and implementing an organized approach to incidents of myocardial infarction to provide for quicker reperfusion therapies to their patients.

The area-which runs the gamut from near-urban settings to the countryside-has transport times ranging from 5-40 minutes. It is approximately 1,100 square miles, with a population of around 300,000, and averages a cardiac arrest a day. Local EMS uses early 12-lead acquisition and interpretation, thrombolytic checklists and Retavase-commonly used in hospitals-as its fibrinolytic of choice.

Retavase is delivered in two doses 30 minutes apart. As an added benefit for field providers, it is not weight-based.

For one patient who received both field TPA and PCI, symptoms of his massive heart attack were classic: chest pain, numbness in the arms, difficulty breathing. But from there on, his case was different from most. EMS arrived and administered oxygen and AHA-recommended acute coronary syndrome drugs (baby aspirin, nitroglycerin and morphine). They also performed a 12-lead, which showed ST segment elevation. The patient rated his pain at 9½ on a 10-point scale.