Sudden cardiac death risk stratification in hypertrophic cardiomyopathy: discrepancies persist among guidelines
Authors: Scolari F L , Garbin H I , Mattos B P 
Published: October 2021

Abstract

Background
Differing criteria have been provided on sudden cardiac death (SCD) risk stratification in hypertrophic cardiomyopathy (HCM) by current guidelines. Recently, AHA/ACC proposed an algorithm with novel clinical markers. It remains to be established the impact of this new approach.

Purpose
Evaluate the impact of the 2020 AHA/ACC guideline on the 2014 ESC and 2011 ACCF/AHA criteria regarding SCD risk assessment and primary prevention implantable cardioverter-defibrillator (ICD) in HCM.

Methods
The database of a HCM center non-referred cohort was accessed for SCD risk profile between March 2007 and March 2020. The agreement for primary prevention ICD recommendations among guidelines was assessed with the Cohen's and Fleiss' Kappa coefficient, P&lt;0.05. SCD or appropriate ICD shock were defined as the primary end-point.

Results
A total of 100 patients, age 60±13 years, 55 (55%) females, were followed by 5±3 years. The maximal left ventricular (LV) wall thickness was 18±4 mm, 38 (38%) patients showed a family history of SCD, 22 (22%) syncope, 6 (6%) ejection fraction ≤50%, 2 (2%) LV apical aneurysm, 1 (1%) massive LV hypertrophy, 26 (26%) non-sustained ventricular tachycardia, and 23 (23%) extensive late gadolinium enhancement. An ICD was placed in 17 (17%) patients. According to the 2020 AHA/ACC guideline, 57 (57%) patients met class IIa recommendation, 27 (27%) class IIb, and 16 (16%) class III. The 2014 ESC model classified 14 (14%) in class IIa, 18 (18%) in class IIb, and 68 (68%) in class III. The 2011 ACCF/AHA considered 66 (66%) in class IIa, 6 (6%) in class IIb, and 28 (28%) in class III. The Cohen's Kappa was 0.200 (95% CI 0.292–0.107), P=0.0005, between the 2020 AHA/ACC and the 2014 ESC, and 0.520 (95% CI 0.651–0.388), P=0.0005, between the North American approaches. The Fleiss' Kappa was 0.219 (95% CI 0.303–0.135) P=0.0005 among the three guidelines, whereas it reached 0.221 (95% CI 0.334–0.108) for class IIa, 0.244 (95% CI 0.357–0.131) for class IIb and 0.202 (95% CI 0.315–0.089) for class III, P=0.0005. Figure 1 shows the patient's reclassification with the new guideline. The primary end-points occurred in 7 (7%) patients in a median follow-up of 6 (17–0.4) years. All of them were classified as IIa with the 2011 ACCF/AHA guideline, but only 4 (4%) met this class under the 2020 AHA/ACC, and none in the 2014 ESC model.

Conclusion
A low agreement was found among guidelines, especially between the 2020 AHA/ACC and the 2014 ESC criteria. The North American systems differed moderately, but the new approach has reduced the cases in class IIa and III recommendation for primary prevention ICD. In contrast, the recent 2020 guideline has increased the number of patients in class IIa in relation to the European model, but both strategies have not protected the totality of patients with SCD or appropriate shock.

Funding Acknowledgement
Type of funding sources: Public hospital(s). Main funding source(s): Hospital de Clínicas de Porto Alegre Figure 1