C81 ROLE OF RESTRICTIVE DIASTOLIC DYSFUNCTION FOR RISK STRATIFICATION OF PATIENTS WITH HYPERTROPHIC CARDIOMYOPATHY: A BAYESIAN MODEL AVERAGING

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Abstract Background Hypertrophic cardiomyopathy (HCM) is characterized by increased left ventricular (LV) stiffness, leading to raised ventricular filling pressures and restrictive diastolic dysfunction (RDD), in itself independently associated with an increased risk of a clinical deterioration. We assessed whether echocardiography evaluation of diastolic function in HCM could yield prognostic value and be useful in HCM risk stratification. Methods We retrospectively reviewed clinical and imaging (echocardiography and cardiovascular magnetic resonance, CMR) data from 361 consecutive patients from two HCM Italian referral centers (Mauriziano Hospital, Turin; University Hospital of Trieste, Trieste). Among them, 28 patients were classified after Doppler echocardiography examination as restrictive (E/A > 1.5, DecT E < 140 ms, E/e’ > 10). The primary endpoint was a large cardiovascular composite consisting of sudden cardiac death (SCD), major ventricular arrythmias (MVAs), heart transplant (HT) and hospitalization for heart failure (HF). Other secondary endpoints were investigated as follows: 1) a secondary arrhythmic endpoint consisting of SCD and MVAs, 2) a key secondary composite of HF, HT, non–SCD. A Bayesian Model Averaging (BMA) was then performed to overcome the bias determined by the limited number of observations. Results Over a mean follow up of 7 ± 3 years, 61 (17%) patients experienced at least one primary composite endpoint event. Of them, 10 were identified with a restrictive diastolic pattern. When BMA was performed, late gadolinium enhancement (LGE) presence at CMR and RDD were significantly associated with the primary composite outcome (respectively, PI = 100, HR = 3.55, pd = 1.00; PI = 74.5, HR = 3.33, pd = 0.99). Left atrium (LA) diameter was not strongly associated with the arrhythmic endpoint, whereas it was significantly associated with the key secondary composite outcome, as well as with increased filling pressures (E/e’) (respectively, PI = 94.5, HR = 1.10, pd = 1.00; PI = 86.8, HR = 1.08, pd = 0.99). Conclusions Restrictive diastolic dysfunction is an independent predictor of poor prognosis in early stages of HCM in absence of systolic dysfunction. In particular, RDD predicted outcomes related to heart failure better then LA diameter and E/e’.