LAUSR

Type of funding sources: None. The knowledge of maternal left ventricular adaptation in twin pregnancies is incomplete. The objective of this study was to longitudinally investigate maternal changes of left ventricular (LV) function and compliance in twin pregnancies. Thirty-five women (age 35.3±4.8 years) with uncomplicated twin pregnancy were enrolled to undergo transthoracic echocardiography at 10-15 (T1) and 30-38 (T3) week’s gestation. Left atrial (LA) and LV dimensions, LV volumes and mass, diastolic parameters (at pulsed wave Doppler and tissue Doppler), global longitudinal strain (GLS) at speckle-tracking imaging, and non-invasive pressure-volume curves (PV loops) were measured and calculated. Maternal LA and LV dimensions, LV volumes and mass had an increasing trend from T1 to T3 (p<0.001 for all). E/A remained stable, while E/e’ ratio slightly increased during gestation. GLS showed no changes between the two visits. At PV loops analysis (Figure 1), LV end-systolic elastance (Ees) and arterial elastance (Ea) both decreased, with no changes in ventricular-arterial coupling (VAC). LV end-diastolic volumes increased from T1 to T3 with no changes in LV end-diastolic filling pressure; the rightward shift of the end-diastolic pressure-volume relationship (EDPVR) suggested enhanced LV cavity compliance (Figure 2). An increase in stroke work was observed. During twin pregnancy GLS and VAC were not modified showing functional adaptation to enhanced haemodynamic load. Importantly, stroke work increase was sustained by enhancement in LV end-diastolic volume with unaltered filling pressure.