686 ASSOCIATION OF PREGNANCY WITH THE NATURAL HISTORY OF WOMEN DIAGNOSED WITH HYPERTROPHIC CARDIOMYOPATHY


 
 
 Hypertrophic Cardiomyopathy (HCM) is the most common genetic cardiomyopathy. However, few studies have systematically investigated the clinical course of pregnancy in hypertrophic cardiomyopathy (HCM).
 
 
 
 To assess whether pregnancy or baseline symptoms at diagnosis or both could drive long-term prognosis in terms of HCM-related events ranging from heart failure to life-threatening arrhythmias and cardiovascular death.
 
 
 
 Women consecutively referred to our Tertiary Clinic for Cardiomyopathies from 1969 to 2019 were retrospectively reviewed. Only women with complete data regarding pregnancy and with a follow up (FU)≥1 year were included in the study. Overall, of the 647 women followed at our center and 378 (58%) fulfilled our inclusion criteria. The peripartum period was defined as the timeframe from -1 to 6 months after delivery. The primary endpoint were major adverse cardiovascular events (MACE: cardiovascular (CV) death, sudden cardiac death (SCD), ICD appropriate shock, and progression of heart failure) at follow-up.
 
 
 
 There were 432 pregnancies in 239 (63%) women with 132(62%) having >1 pregnancy. A total of 139(37%) reported no pregnancy. Twenty-nine (7.6%) women had 39 pregnancies after HCM diagnosis and were followed by the obstetrics department. Instrumental characteristics were comparable among women. Thirty percent presented with obstructive physiology at baseline. Among the 39 pregnancies in women who had a pregnancy after the diagnosis, there were 3 MACEs in the peripartum period (1 cardiac arrest, 1 sustained ventricular tachycardia and 1 episode of acute heart failure). Of note, the three women had a likely pathogenic genetic variant on the TNNI3, TNNT2 and MYH7 genes.
 Long-term (FU: 10±9 years), at Cox multivariable analysis, after correction for obstructive physiology and LA diameter, pregnancy (Hazard Ratio [HR]: 0.605, 95% Confidence Interval [C.I.] 0.380-0.963, p=0.034), age at diagnosis (HR: 1.034, 95% C.I. 1.018-1.050, p<0.001) and NYHA Class (II vs I: HR 1.944, 95% C.I 0.896-4.218; III vs I: HR 5.291, 95% C.I. 2.392-11.705, overall p<0.001) were associated with MACE. NYHA class also proved to be a predictor for MACE in women with pregnancy (II vs I: HR 1.200, 95% C.I 0.463-3.106; III vs I: HR 3.040, 95% C.I. 1.062-8.705, overall p=0.022). Notably, in this group, number of pregnancies was not associated with unfavorable outcome (HR: 1.170, 95% C.I. 0.593-2.308, p=0.650).
 Age and symptoms were also associated with MACE in women without pregnancy.
 
 
 
 Women with HCM tolerate pregnancy well. Although rare, adverse events during the peripartum period may arise and the risk should be discussed during ante-natal counselling. Age and NYHA class were the main drivers of long-term outcome. These findings suggest that while pregnancy can be safely pursued there is a need for close monitoring for heart failure symptoms prior to and during pregnancy.
