Author + information
- Paolo Angelini, MD∗ ()
- ↵∗Center for Coronary Artery Anomalies, Department of Cardiology, Texas Heart Institute, 6624 Fannin, Suite 2780, Houston, Texas 77030
The report by Finocchiaro et al. (1) provides a valuable occasion for revisiting the difficult task of assigning a potential primary cause and determining the etiology in cases of sudden cardiac death (SCD). Assigning a primary cause usually involves guesswork, and determining the etiology can be even more complex if it is assumed that the etiology is the ultimate nature (e.g., genetic defect) of the immediate cause.
One reason for these difficulties is that the list of “candidate conditions” believed to possibly cause SCD is not yet clearly defined. For example, coronary hypoplasia, a missing coronary artery, myocardial bridging, mitral valve prolapse, and bicuspid aortic valves have traditionally and empirically been regarded as causes, although their generic inclusion may lack justification. Placement of variably important conditions such as coronary artery anomalies into a single group is obviously inappropriate for characterizing risk. Subclassification of “type” and evaluation of individual case severity are fundamental. Typically, bicuspid aortic valves can cause SCD, but the relevant factor for risk characterization should be the severity of the resulting aortic stenosis and/or insufficiency (functional defect).
In addition, because of the limitations implicit in assigning the cause of SCD based only on autopsy data, my group (the Center for Coronary Artery Anomalies and Prevention of SCD in the Young, at the Texas Heart Institute) (2) has recently proposed that an objective and quantitative method be used to address the issue of high-risk cardiovascular conditions (hr-CVCs) in sports participants. The proposed method includes the following steps:
1. Start with an accurate account of the prevalence of a given hr-CVC in a general population. For example, in an extraordinarily large study of a general population screened by cardiac magnetic resonance imaging (which has optimal accuracy for identifying serious coronary anomalies), my group found that one of the most lethal hr-CVCs, anomalous origin of the left coronary artery from the opposite sinus with an intramural course (L-ACAOS-IM) (3) has a prevalence of ∼0.1% (4).
2. Perform in vivo intravascular ultrasound imaging of coronary anomalies (4). This method can provide objective proof of a pathophysiological mechanism and determine stenosis severity.
3. Quantitatively evaluate the severity of exercise and mortality. This can be done by referring to the groundbreaking survey of U.S. military recruits who underwent a 2-month boot camp, during which autopsies were performed and reported in all cases of death (5). Of the 6.3 million recruits, 64 had SCDs that were considered due to autopsy-identifiable cardiac abnormalities. That corresponds to an annualized SCD-related mortality rate of 13.0 of 100,000 per year.
It can be assumed that 6,290 recruits had L-ACAOS, based on the 1 of 1,000 prevalence of that condition in a general unscreened population of children. If the military study documented 21 cases of L-ACAOS-IM (involving SCD during strenuous exercise over 2 months), it can be concluded that the annual incidence of SCD in such carriers is 2,150 of 100,000. Comparing the risk of SCD in the L-ACAOS-IM group versus other recruits, it can also be concluded that the risk ratio is 2,150 of 100,000/11.1 of 100,000, or 194 times greater. This discipline clearly documents and quantifies an hr-CVC.
This method would also be useful for judging the value of effective screening, indications for intervention, and need for disqualification of young persons from participation in sports.
The Finocchiaro et al. (1) study is admirable in its size and depth of detail, and the investigators should be applauded for their dedication to this valuable research. However, I believe that autopsy often cannot clarify all the involved issues and that further work is urgently needed to address methodological considerations.
Please note: Dr. Angelini has reported that he has no relationships relevant to the contents of this article to disclose.
- American College of Cardiology Foundation
- Finocchiaro G.,
- Papadakis M.,
- Robertus J.L.,
- et al.
- Angelini P.,
- Uribe C.,
- Monge J.,
- Tobis J.M.,
- Elayda M.A.,
- Willerson J.T.