The Science of SMHeartCard
SMHeartCard solves a big problem: many Canadians are at risk of heart attack but don't have a simple way to carry ASA and nitroglycerin. Guidelines recommend immediate treatment for a heart attack to improve survival (1), because minutes matter. In a study of 38 consecutive Canadian patients with known coronary artery disease prescribed standard Nitroglycerin and ASA, only 20% of patients, and only 11% of men, carried their Nitroglycerin with them; none carried ASA (2).
Nitroglycerin is a fragile chemical that reacts with air and standard plastics. SMHeartCard uses a new, patent-pending technology to seal Nitroglycerin pills in a chemically inert case away from oxygen, moisture, and light that can break down Nitroglycerin. SMHeartCard seals ASA and Nitroglycerin pills from air and moisture and light (3), and the pills remain potent for 6 months.
SMHeartCard performance was validated at the University of Alberta Faculty of Pharmacy and Pharmaceutical Sciences in the laboratory of Professor Neal Davies. These comprehensive studies show that SMHeartCard effectively keeps Nitroglycerin and ASA tablets ready for when you need them (4). A wide range of storage conditions have been tested, including validation across a range of temperatures ranging from -20 degrees Celsius to 60 degrees Celsius. SMHeartCard performs as well at body temperature as when pills are stored in the manufacturers packaging unopened, at room temperature, for six months.
At the time of a heart attack, ASA works to stop platelets from sticking to the side of a coronary artery and making blood clots worse. Early ASA has been shown to markedly improve the chances of surviving a heart attack (5). Nitroglycerin works to open up the coronary arteries and reduce the workload of the heart; this reduces its need for oxygen, reduces chest pain, and pre-hospital nitroglycerin is associated with improved survival (6). Pre-hospital administration of nitroglycerin is safe, with asymptomatic low blood pressure occurring in up to 3% of people (7). Early administration of nitroglycerin in hospital improves survival after myocardial infarction (8).
Recent studies show that daily aspirin to prevent heart attacks is ineffective in those 70 years and older (9): it is better to use the SMHeartCard approach of "ready and available when needed".
1. 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction. O'Gara PT et. al. J Am Coll Cardiol. 2013;61(4):e78-e140.
2. Poor Compliance With Carrying Nitroglycerin and Aspirin in Patients With Coronary Artery Disease. Canadian Journal of Cardiology, Horseman et. al. 2018.
3. Improving compliance and access to nitroglycerin and aspirin in people with coronary artery disease: development and validation of the SMHeartCard system. Canadian Cardiovascular Congress, Le T, Davies N, et. al. 2018.
4. Development and validation of a compact on-person storage device (SMHeartCard) for emergency access to acetylsalicylic acid and nitroglycerin. Le T, Davies N, et.al. Canadian Medical Association Journal, in press, 2020.
5. Randomised trial of intravenous streptokinase, oral aspirin, both, or neither among 17,187 cases of suspected acute myocardial infarction: ISIS-2. Lancet. 1988;2(8607):349-60.
6. Determinants of pre-hospital pharmacological intervention and its association with outcome in acute myocardial infarction. Strandmark R et al. Scand J Trauma Resusc Emerg Med. 2015;23:105.
7. Prehospital high-dose sublingual nitroglycerin rarely causes hypotension. Clemency BM et. al. Prehosp Disaster Med. 2013;28(5):477-81.
8. Effect of early treatment with anti-hypertensive drugs on short and long-term mortality in patients with an acute cardiovascular event. Perez MI, Musini VM, Wright JM. Cochrane Database Syst Rev. 2009(4):CD006743.
9. Effect of Aspirin on Disability-free Survival in the Healthy Elderly New England J Med, McNeil J et. al. 2018.