586 BODY WEIGHT AND MICROVASCULAR DYSFUNCTION IN PATIENTS WITH HYPERTROPHIC CARDIOMYOPATHY AT LOW CARDIOVASCULAR RISK REFERRED TO POSITRON EMISSION TOMOGRAPHY


 
 
 Whether obesity, a modifiable risk factor in patients with hypertrophic cardiomyopathy (HCM), can influence coronary microvascular dysfunction (CMD) is unknown.
 
 
 
 To assess the relationship between body weight and CMD measured with myocardial blood flow (MBF) at positron emission tomography (PET) in patients with HCM.
 
 
 
 All consecutive patients with HCM referred to PET scan from 2010 to 2020 were reviewed. Only patients with PET and cardiac magnetic resonance (CMR) analysis, <60 years old at diagnosis, with no history of diabetes, dyslipidemia, and hypertension were included.
 Patients were classified into three groups according to baseline BMI: BMI<25 kg/m2, BMI 25-30 kg/m2, and BMI>30 kg/m2.
 
 
 
 Of 1512 patients with HCM, 134 (8.9%) had been referred to a PET scan and 79 (5.2%) met the inclusion criteria (29% were women, median age was 44 [28-53] years). Overall, 52% had a BMI<25 kg/m2, 37% had a BMI 25-30 kg/m2, and 11% had a BMI >30 kg/m2.
 At PET, average MBF was 2.08 [1.52-2.40] ml/min/g and was similar among BMI groups (p=0.288) irrespective of fibrosis at CMR. Prevalence of severe microvascular dysfunction was similar (MBF <1.53 ml/min/g: (9 [22%] vs 8 [28%] vs 2 [22%], among study groups, p=0.833). Age at PET and atrial fibrillation were associated with MBF.
 
 
 
 Obesity is not associated with worsening of CMD in HCM patients. These findings support the hypothesis that the worse symptomatic profile in obese HCM patients is due to increased prevalence of obstruction rather than accentuation of structural phenotype. Thus, the symptomatic handicap associated with obesity may be reversible following appropriate weight-reduction strategies
