Updated: Sep 19, 2018
Sudden Cardiac Death From the Perspective of Coronary Artery Disease
Sara, Jaskanwal D. et al.
Mayo Clinic Proceedings , Volume 89 , Issue 12 , 1685 – 1698
SCD = Sudden Cardiac Death
The incidence of SCD ranges from 0.36 to 1.28 per 1000 persons per year, with approximately 400,000 deaths annually in the United States alone
400,000 Sudden Cardiac Deaths Yearly
80% (320,000) due to Coronary Artery Disease, most had no documented history of CAD.
Although evidence of CAD is detected subsequently in 80% of SCDs, most of these deaths occur in apparently normal, asymptomatic adults with no documented history of CAD. High-risk groups such as patients who have had acute MI within the previous year have SCD rates higher than 30% but account for a small minority of the total number of cases per year.
Determination of cardiovascular risk and institution of appropriate statin and antiplatelet therapy is one of the most effective primary prevention strategies to lower CAD mortality. Risk stratification tools such as the Framingham risk score are helpful in identifying at-risk groups at the population level but have limited utility in individual patients because they fail to include all known “conventional” cardiovascular risk factors, such as family history of premature CAD, and do not incorporate “nonconventional” risk factors, such as body mass index, that are also clinically relevant.
Additional screening tools for subclinical atherosclerosis, including computed tomographic coronary calcium scoring and carotid intima-media thickness, may also facilitate the identification of at-risk individuals who may otherwise be unidentified using traditional risk scores. In one study, patients 65 years and younger without diabetes mellitus who were not taking statins underwent ultrasonography to assess carotid intima-media thickness.
Of 441 patients, 336 had a low risk Framingham score (5% risk of cardiovascular disease within 10 years), but 38% of this group had increased carotid intima-media thickness on ultrasonography, which has been shown to predict a higher risk of future MI in several studies. In light of these findings, the preventive regimens were intensified in 70% of this apparently low-risk group through initiation of lipid-lowering therapy, aspirin, or both. In keeping with the National Cholesterol Education Program guidelines, only 4.7% of patients with a low Framingham score in this study would have been candidates for lipid-lowering therapy.