DK2985_C000 1..28 - AlSharqia Echo Club

Congenital Heart Disease 541Supravalvular stenosis is rarely an isolated occurence.It may be part of a tetralogy of Fallot or the William’ssyndrome, Noonan’s syndrome, Allagyl’s syndrome(arteriohepatic dysplasia), or the congenital rubellasyndrome.Moderate to severe sub- and supravalvar stenosis canonly be relieved surgically.TEE in RVOT Obstruction (Table 24.2)Transesophageal echocardiography evaluation preoperativelymust confirm the diagnosis, demonstrate theseverity of the obstruction and identify associatedanomalies. The RVOT is best visualized with the midandupper-esophageal right ventricular outflow views(see Chapter 19, Fig. 19.17). Transgastric views centeredon the right heart may help to determine the gradient,usually at 90–1208. Postoperatively, after reconstructionof the RVOT with a pericardial patch or repair with aconduit or a homograft, TEE should identify residual stenosisand surgically induced PV regurgitation.2. Tetralogy of FallotThe tetralogy of Fallot is one of the most commoncomplex congenital cardiac malformations found inadults. (1) The primary anomaly underlying this malformationis an anterocephalad deviation of the outletseptum, resulting in RVOT obstruction which is usuallyinfundibular, but can also be valvular or supravalvular.The other components of the tetralogy are secondary tothe hypoplastic infundibulum and anterior and rightwarddisplacement of the conal septum. (2) As the latter is nolonger aligned with the trabecular septum, an anteriormalalignment subaortic VSD is present and usuallynonrestrictive. (3) The AoV is displaced anteriorly and tothe right following the conal septum, overriding the trabecularseptum (Fig. 24.22). (4) Right ventricular hypertrophyis secondary to the systemic pressure in the RV dueto the nonrestrictive VSD. The severity of the diseasedepends largely on the degree of narrowing of the infundibulum,ranging from mild hypoplasia with good antegradeflow through the RVOT with mild cyanosis, to completeatresia of the infundibulum with no antegrade flow to thepulmonary arteries. The patient is then dependent on pulmonaryblood flow coming either from aortopulmonarycollaterals or from a PDA. Collaterals may originate anywherein the arterial system but usually arise from the descendingAo and the transverse arch. Other associatedfeatures include additional muscular VSDs, anomalouscoronary arteries, right aortic arch, PDA, aortic rootdilation, and ASD. The major coronary artery anomaliesinclude a prominent right conal artery, or an anterior descendingcoronary originating from the right coronaryartery.Adults presenting with a tetralogy of Fallot can be separatedinto three groups (10): (1) the patients who(A)(B)LVLAAoRV(C)VSDFigure 24.22 (A, B) Tetralogy of Fallot. Mid-esophageal long-axis view, showing a ventricular septal defect (VSD) and the aortic rootoverriding the ventricular septum. (C) Truncus arteriosus: note the similarity with tetralogy of Fallot. There is however a separate originfor the pulmonary artery in the tetralogy abnormality (Ao, aorta; LA, left atrium; LV, left ventricle; RV, right ventricle). [Photo A, modifiedwith the permission from Miller-Hance et al. (1) and Photo C courtesy of Dr. François Béïque.]