Congenitally Corrected Transposition of the Great Arteries (ccTGA)
Congenitally corrected transposition of the great arteries (ccTGA) is rare, accounting for approximately 0.4% of congenital heart malformations., Baron Rokitansky first described this defect in 1875. In ccTGA there is “double discordance” – atrioventricular and ventriculoarterial discordance such that sequence of blood flow through the heart is morphologic left ventricle to the pulmonary artery and lungs and then flow of oxygenated blood from the morphologic right ventricle through the aorta to the systemic circulation. Associated defects occur in 70-90% of patients and include ventricular septal defect, left ventricular outflow tract (pulmonary valve or subpulmonary) obstruction and tricuspid valve anomalies. In addition, the conduction system is often abnormal and unstable over time, with heart block occurring at an estimated rate of 2% per year after diagnosis.,,
Treatment of ccTGA is dependent on many factors, but includes observation with close follow-up, medical therapy for heart failure, pacemaker insertion, and surgery., Despite isolated case reports of preserved morphological right ventricular function in advanced age, there is general agreement that the fundamental problem is the inability of the morphologic right ventricle and tricuspid valve to support the systemic circulation long term., To address this fundamental issue, techniques have been developed to both correct the associated defects and restore a concordant circulation with the morphological left ventricle supporting the systemic circulation. Our understanding of which management strategy is best suited for a given patient continues to evolve.
In this chapter, we will focus on the management of the patient with ccTGA with two functional ventricles, review the basic principles, and provide detailed information about management strategies and surgical techniques. Particularly with ccTGA, it is critical to be clear on the usage of the words “left” and “right” to ensure clarity and accuracy regarding anatomic sidedness versus intrinsic morphologic nature. In this chapter, we attempt to consistently specific morphological (m) versus anatomic sidedness (mLV or mRV). However, in certain potentially ambiguous cases in which only “left” or “right” are used, “left” or “L” denotes structures supporting the systemic circulation; and right denotes those supporting the pulmonary circulation. For example, the left ventricular outflow tract would correspond to the subpulmonary outflow tract unless otherwise specified.
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