Acquired right ventricular outflow tract obstruction in twin‐to‐twin transfusion syndrome; a prospective longitudinal study

Abstract

Objective The pathophysiology of right ventricular outflow tract obstruction (RVOTO) in twin‐to‐twin transfusion syndrome (TTTS) recipients is incompletely understood. We aimed to investigate the development and spectrum of RVOTO in TTTS recipients. Methods A prospective longitudinal cohort study was conducted between 2015 and 2017. Echocardiographic assessment was performed in recipients from TTTS diagnosis until the neonatal period. Results Prenatal RVOTO, defined as abnormal flow velocity waveforms across the pulmonary valve (PV), was diagnosed in 12.9% (16/124) of recipients at TTTS diagnosis. Postnatal RVOTO was found in 6.7% (7/105) of surviving recipients. All recipients with severe postnatal RVOTO showed prenatal RVOTO at TTTS diagnosis. In 5.6% (6/108) of cases, prenatal RVOTO appeared only after laser therapy, and in 1.9% (2/108), this progressed to mild postnatal pulmonary stenosis. Elevated peak systolic PV velocities were more frequently associated with postnatal RVOTO compared with prenatal finding of functional pulmonary atresia. Postnatal RVOTO was associated with early manifestation of TTTS but was equally found in all Quintero stages. Conclusion In the spectrum of postnatal RVOTO, severe cases show prenatal RVOTO at TTTS diagnosis. However, RVOTO can develop after laser or even in the neonatal period and in all Quintero stages. A potential risk factor for postnatal RVOTO is early TTTS manifestation.

Twin to twin transfusion syndrome

“…Changes in recipient cardiac function may be observed prior to development of overt TTTS and may include cardiac enlargement, biventricular hypertrophy, valvular regurgitation, impaired contractility (23,24). Right ventricular hypertrophy and hypertension coupled with tricuspid regurgitation may lead to decreased flow through the pulmonary valve and right outflow tract, essentially creating a functional subvalvular right ventricular outflow obstruction in up to 9% of recipients (25)(26)(27). These findings may resolve after treatment but persistent pulmonary stenosis or functional atresia may result and require postnatal treatment (28).…”

Main Patterns of Fetal Cardiac Remodeling

“…Pressure Overload. Pulmonary/aortic stenosis [5,11], twin-to-twin transfusion syndrome [12][13][14], placental disease [15], and conception by assisted reproductive technologies [16] induce pressure overload and trigger a fetal heart response by initially changing to a more globular shape (to better tolerate wall stress) and subsequently further increas-Fetal Diagn Ther 2020;47:337-344 DOI: 10.1159/000506047 ing the contractile force (myocardial hypertrophy) as well as decreasing the inner diameter of the chamber.…”

“…Volume Overload. Prenatal volume overload occurs in fetal anemia [17], vascularized tumors [17], severe intrauterine growth restriction [6,15,18,19], abnormal venous drainage [20], or twin-to-twin transfusion syndrome [12,14]. The natural response is to enlarge heart dimensions (cardiac dilation), thus increasing the stroke volume with every beat, in order to better manage the increased blood volume.…”

“…2d). This eccentric hypertrophy is usually associated with mild pericardial effusion, decreased longitudinal function, impaired relaxation [14,27], and abnormal regional deformation [28], with preserved ejection fraction in most cases. The pathophysiology of cardiac remodeling and dysfunction under placental insufficiency has been proposed to be caused by complex interactions [15].…”

Novel Technique for the Measurement of Fetal Right Modified Myocardial Performance Index Using Synchronized Images of Right Ventricular Inflow and Outflow and Clinical Application to Twin‐to‐Twin Transfusion Syndrome

“…Owing to their unique blood circulation, fetuses are right heart‐dominant 9 . Therefore, it is important to evaluate not only the left ventricular function but also the right ventricular (RV) function of compromised fetuses, such as those with twin‐to‐twin transfusion syndrome (TTTS) 10,11 . However, the right Mod‐MPI measurement is more complex and has some limitations.…”