The HCM Risk–SCD Score
In 2014, the European Society of Cardiology (ESC) introduced a numerical predictor (the “HCM Risk–SCD score”) to assist physicians in identifying those patients at highest risk for sudden cardiac death who would benefit from the implantation of a prophylactic implantable cardioverter-defibrillator.
Using an algorithm generated by the answers to a series of questions, the tool estimates the 5-year risk of sudden cardiac arrest for any particular patient. You can find the tool online here.
About the HCM-EVIDENCE Study
The reliability of this tool was recently evaluated by the HCM-EVIDENCE study, the results of which were presented at the recent ESC meeting in Barcelona. This study examined the reliability of the HCM Risk–SCD score in 3,703 patients. The study looked at whether the scores accurately predicted the risk of sudden cardiac arrest (SCA) in particular patients. The results of the study showed that the tool was useful in distinguishing high from low- risk patients.
Patients who were classified as low risk (whose score predicted less than a 4% chance of a SCA over a 5-year period) had an actual incidence of SCA of 1.4%, while those classified as high risk (with a score predicting a chance of SCA that was greater than or equal to 6% over a 5-year period) had a SCA incidence of 8.9%.
According to the British investigator who led the study, Dr. Constantinos O’Mahoney, “…for every 13 high-risk patients who receive an ICD as recommended by ESC guidelines, one patient could potentially be saved from SCD ...The study also showed that a low score on the HCM Risk-SCD calculator helped avoid unnecessary ICD implants in low risk patients, supporting the 2014 ESC recommendation not to implant ICDs in these individuals.”
Potential Impact of HCM-EVIDENCE Study
Dr. O’Mahoney added that while there is no way to predict and prevent all SCAs, the HCM Risk-SCD calculator help patients to better conceptualize the level of risk which can assist the shared decision-making process .
Dr. Nancy Sweitzer of the Sarver Heart Center at the University of Arizona was interviewed by MedPage Today about the study while at ESC. Dr. Sweitzer observed that the HCM Risk-SCD calculator could assist in convincing a U.S. health insurer that an ICD is justified in specific cases, since the tool puts the risk of sudden cardiac arrest into quantifiable terms which have now been shown to correlate to actual outcomes.
[Editor’s Note – I tried the calculator out myself. It suggested that I get an ICD. I came to the same decision with the advice of several physicians 15 years ago. Though it has never been called upon to do its job, I am glad to have it, just in case.]
Update: 12/2/2017 – This retrospective study validated the utility of the guidelines.