Complex Congenital Heart Diseases

Abstract

Complex congenital heart disease (CHD) includes a wide spectrum of anatomical anomalies. Most of complex

CHDs are usually diagnosed with echocardiography at birth and, in the recent era, during pregnancy; unfortunately, most of these anomalies are candidates during their life to more than one surgical/interventional procedure and/or palliation. Advanced non-invasive imaging is indicated in selected cases mainly when transthoracic echocardiography (TTE) is not exhaustive and both CMR and cardiac computed tomography (CCT) are accurate tools.

CMR certainly provides extensive morphological information about intra and extracardiac anatomy together with functional and hemodynamic assessment. There is large evidence that patients treated for complex CHD require longitudinal follow-up to monitor residual morbidity and to guide management. Current guidelines also recommend lifelong CMR follow-up in most complex adult congenital heart. Multiples anatomical anomalies may coexist in complex CHD. CMR provides high-resolution imaging of intracardiac and extracardiac anatomy in any imaging plane without the acoustic window limitations of echocardiography, the exposure to ionizing radiation of CCT, or the possible complications of an invasive diagnostic catheterization. The anatomy visualization and vessels measurements can be also performed without using contrast medium, by using non-contrast-enhanced volume acquisition. CMR is also the gold standard for the evaluation of biventricular volumes and function. Of particular importance in complex CHD is the evaluation of the RV. Flow imaging is a strategic asset of CMR protocols in complex CHD for the quantification of shunt, valves regurgitation, flow distribution in pulmonary branches, Fontan hemodynamics; in complex CHD these elements can lead to better understand the pathophysiological mechanism that contribute to the outcome of these patients. CMR in combination with invasive catheterization could also evaluate pulmonary vascular resistance. The heterogeneity and complexity of congenital heart disease require a certified expertise in CMR techniques, deep knowledge in congenital heart diseases, and a multimodality/multidisciplinary approach.