Response to Correspondence by Piacentini et al.

Excerpt

We thank Piacentini et al. for taking interest in our recent report entitled “Dichorionic Diamniotic Twin Pairs with Complex Congenital Heart Disease” and also for their thoughtful comments [1]. It is indeed fascinating that aortic coarctation was common in their cohort of dichorionic diamniotic twins. The two studies were however fundamentally different. We only included dichorionic diamniotic twin pairs where both the twins had complex congenital heart disease. In the twin pairs reported by Piacentini et al., only one of the twin pairs had coarctation of aorta (smaller twin) while the larger twin either had no heart disease or had minor heart disease such as an isolated ventricular septal defect (VSD) or left ventricular (LV) hypertrophy [2]. In addition, the authors do not report if there were confounders such as maternal diabetes which can be associated with both congenital heart disease and left ventricular hypertrophy [3]. Though karyotyping was performed in their cohort, it is unclear if any additional genetic testing was obtained. The authors also do not provide details about the VSDs noted in two of their twins with coarctation of aorta. Posterior malalignment VSDs are well known to be associated with coarctation of aorta therefore a detailed morphologic description of the VSD would have been helpful in determining if the coarctation was related to the VSD or to the overall decreased flow hypothesis that the authors have proposed [4]. …