Prevalence of mitral valve diseases in the newborn – a large population-based study of newborns

Abstract

Abstract Background Mitral valve abnormalities (MVA) include mitral valve regurgitation (MR), mitral valve prolapse (MVP), Barlow's mitral valve disease, and parachute MV. The prevalence of MVA has yet to be determined in an unselected population of newborns. Objective To determine the prevalence of MVA in unselected newborns and to assess the left ventricular (LV) structure and function in the neonatal heart with MR. Methods Transthoracic echocardiography (TTE) was performed within 28 days after birth in unselected neonates consecutively included in a prospective, multicenter, population-based study (2016–2018 (n=25,751)). TTE's were systematically reviewed for MR, MVP, Barlow's MV disease, and parachute MV. In a subgroup of 400 newborns with MR, the regurgitation was further classified as either traceable MR, mild MR, or moderate/severe MR based on the ratio of the trans-mitral jet in systole over the diastolic filling duration using M-mode in the 4-chamber view of the LV. Results Of 25,751 included newborns, we found a prevalence of MVA of 26.7%. (6,883/ 25,751). The prevalence of MR was 26.2%, MVP was 0.35%, Barlow's disease was 0.13%, and parachute mitral valve was 0.027%. MR was more frequent in females compared to males (50.4 vs 48.2%, p<0.01). Newborns with MR had enlarged left atrial diameter (11.91±2.03 mm vs 11.53±2.02 mm, p<0.01) and LV end-diastolic and end-systolic diameter (LVIDd 19.98±1.88 mm vs 19.87±1.83 mm, p<0.01, LVIDs 13.48±1.47 mm vs 13.31±1.41 mm, p<0.01), thicker LV posterior wall (2.19±0.60 mm vs 2.05±0.52 mm, p<0.01), increased early and atrial mitral inflow velocities (MV E velocity (0.65±0.14 m/sec vs 0.61±0.13 m/sec, p<0.01), MV A velocity (0.60±0.13 m/sec vs 0.57±0.13 m/sec, p<0.01)), but lower fractional shortening (32.54±4.22% vs. 32.96±4.17%, p<0.01) as compared to newborns without MVA. In subgroup analysis MR severity was classified as traceable in 44% (175/400) of cases, mild MR in 52% (209/400) of cases and moderate/severe MR in 4% (16/400) of cases. Comparing traceable MR with moderate/severe MR (19.48±1.88 mm vs 20.96±2.64 mm, p=0.01) and comparing mild MR with moderate/severe MR (19.85±1.92 mm vs 20.96±2.64 mm, p=0.04) showed significant increases in LV end-diastolic diameter. Conclusion Over one fourth of all newborns had a MV abnormality of which mitral regurgitation accounted for the vast majority. The presence of MR was associated with asymmetric LV remodeling and discrete changes in LV function. Subgroup analysis revealed that increment in MR severity was primarily associated with an increase in LV end-diastolic diameter. Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): Herlev-Gentofte Hospital