Justin T. Tretter

Defining and refining indications for transcatheter pulmonary valve replacement in patients with repaired tetralogy of Fallot: Contributions from anatomical and functional imaging

Transcatheter pulmonary valve replacement (TPVR) is an important treatment option in repaired tetralogy of Fallot (TOF) and right ventricular outflow tract (RVOT) dysfunction. Indications for timing of TPVR are extrapolated from surgical pulmonary valve replacement guidelines, which are themselves controversial as published evidence is scarce and expert opinion therefore prevails. We review current indications for PVR following TOF repair, focusing on those for TPVR specifically, and discuss anatomical and functional considerations as these pertain to determination of candidacy for TPVR. Hemodynamic assessment surrounding PVR has focused on assessment of the right ventricle (RV) size and systolic function, with the goal of intervening in the asymptomatic patient prior to the development of irreversible RV deterioration and right heart failure. The impact of abnormal RV mechanics on the LV has been appreciated, with the assessment of LV function assuming higher priority in decision-making regarding possible PVR. In addition to the standard volumetric assessment, evaluation with indices of myocardial wall strain, tissue velocities, diastology, and ventricular response to exercise is emerging as tools with potential to further refine timing of PVR. We conclude that, at present, current evidence, although limited, supports a more aggressive approach in those who meet inclusion for TPVR in patients with repaired TOF and RVOT dysfunction guided by the discussed hemodynamic assessment, however, more importantly this review should lay the framework for future investigations regarding hemodynamic assessment of this population.

The Significance of the Interleaflet Triangles in Determining the Morphology of Congenitally Abnormal Aortic Valves: Implications for Noninvasive Imaging and Surgical Management

A comprehensive understanding of the normal and abnormal aortic root is paramount if we are to improve not only our assessment of the aortic root and its components but also the surgical approach to reconstructing this complex structure when congenitally malformed. Most anatomic and imaging-based classifications of the normal root recognize and describe the basic components, which include the shape and size of the three aortic sinuses and their three valvar leaflets, as well as the sinutubular junction and proximal ascending aorta. However, the three interposing fibrous interleaflet triangles, which share an intimate relationship with all elements of the root, are often ignored. In consequence, the important role the interleaflet triangles play in determining the function of the normal and congenitally malformed aortic root is underappreciated. Additionally, the subtle asymmetries found in the normal aortic root, such as differences between the sizes of the described components, underlie its hemodynamic efficiency. In this review the authors describe the complex structure of the normal aortic root, contrasting these normal characteristics with those found in the unicuspid and bicuspid variants of congenitally malformed aortic valves. Many of these features are readily recognizable using current imaging modalities and so should become a standard part of the description of aortic valvar disease. The authors believe that this thorough morphologic approach will provide a framework for the re-creation of a more normal aortic root at the time of repair or replacement, thereby improving current outcomes.

Utility and Scope of Rapid Prototyping in Patients with Complex Muscular Ventricular Septal Defects or Double-Outlet Right Ventricle: Does it Alter Management Decisions?

Rapid prototyping facilitates comprehension of complex cardiac anatomy. However, determining when this additional information proves instrumental in patient management remains a challenge. We describe our experience with patient-specific anatomic models created using rapid prototyping from various imaging modalities, suggesting their utility in surgical and interventional planning in congenital heart disease (CHD). Virtual and physical 3-dimensional (3D) models were generated from CT or MRI data, using commercially available software for patients with complex muscular ventricular septal defects (CMVSD) and double-outlet right ventricle (DORV). Six patients with complex anatomy and uncertainty of the optimal management strategy were included in this study. The models were subsequently used to guide management decisions, and the outcomes reviewed. 3D models clearly demonstrated the complex intra-cardiac anatomy in all six patients and were utilized to guide management decisions. In the three patients with CMVSD, one underwent successful endovascular device closure following a prior failed attempt at transcatheter closure, and the other two underwent successful primary surgical closure with the aid of 3D models. In all three cases of DORV, the models provided better anatomic delineation and additional information that altered or confirmed the surgical plan. Patient-specific 3D heart models show promise in accurately defining intra-cardiac anatomy in CHD, specifically CMVSD and DORV. We believe these models improve understanding of the complex anatomical spatial relationships in these defects and provide additional insight for pre/intra-interventional management and surgical planning.

Assessment of the anatomical variation to be found in the normal tricuspid valve

The normal tricuspid valve is tri‐leaflet, supported by tendinous cords, which are themselves supported by papillary muscles. There can be marked variation in the anatomy of the normal tricuspid valve, which must be understood to differentiate it from pathological malformations. The tricuspid valve of 100 normal heart specimens was examined. The three leaflets of the tricuspid valve, along with the papillary muscles supporting the zones of apposition were identified, and details of the anatomy recorded and analyzed. All three leaflets were identified in all 100 hearts. The septal leaflet had tendinous cord attachments in 93 specimens to the ventricular septum. The medial papillary muscle had a single head in the majority of specimens, supporting the zone of apposition with the antero‐superior leaflet in 97 specimens. The anterior papillary muscle attached to the mid‐portion of the antero‐superior leaflet in 62 specimens, and supplied the zone of apposition between the antero‐superior and inferior leaflets in 81 specimens. There were rough zone cord attachments to the antero‐superior leaflets in all specimens. The inferior leaflet had basal cord attachments in 87 specimens, with attachments to multiple small muscular heads in 37 specimens. The inferior papillary muscle was well formed in only 58 specimens. Although certain features are relatively constant, multiple variations in the normal tricuspid valve have been identified. Knowledge of these normal variations is necessary in understanding the function of this complex valve apparatus, along with the potential for pathology. Clin. Anat. 29:399–407, 2016.

Aortic Wall Injury Related to Endovascular Therapy for Aortic Coarctation

Aortic wall complications can occur in unrepaired aortic coarctation (CoA) and after surgical repair or endovascular treatment. This review summarizes the available literature and current understanding of aortic wall injury (AWI) surrounding the management of CoA, focusing specifically on acute and follow-up AWI after endovascular treatment. There have been 23 reported cases of aortic rupture after endovascular treatment for CoA, including angioplasty alone, bare metal stenting, and primary covered stent therapy. Even if these published cases represent only a minority of ruptures that have actually occurred, the incidence is substantially <1%. The incidence of acute aneurysm formation was 0% to 13% after angioplasty, 0% to 5% after bare metal stent placement, and <1% after covered stent placement. The reported incidence and natural history of both acute and new AWI during follow-up after endovascular therapy for CoA varies considerably, likely secondary to ascertainment and reporting biases and inconsistent definitions. Although important AWI after endovascular treatment of CoA seems to be declining in frequency with increasing experience and improving technology, it remains one of the most important potential adverse outcomes. Long-term surveillance for new AWI and monitoring of existing AWI is mandatory, with institution of appropriate treatment when necessary. A central research focus in this population should be determination of the appropriate treatment for both native and recurrent CoA across various ages with regard to limiting recurrent CoA and preventing associated aortic wall complications, in addition to determining the appropriate treatment of various AWI. Consistent definitions and reporting are necessary to truly understand the incidence of, risk factors for, and measures protective against AWI after angioplasty or stent implantation for CoA.

Surgical planning for a complex double-outlet right ventricle using 3D printing

Rapid prototyping may be beneficial in properly selected cases of complex congenital heart disease, providing detailed anatomical understanding that helps to guide potential surgical and cardiac catheterization interventions. We present a case of double‐outlet right ventricle, where the decision to obtain a three‐dimensional printed model helped for better understanding of the anatomy, with the additional advantage of surgical simulation in planning the surgical approach and type of surgical repair.

Noninvasive Imaging in Adult Congenital Heart Disease

Multimodality cardiovascular imaging plays a central role in caring for patients with congenital heart disease (CHD). CHD clinicians and scientists are interested not only in cardiac morphology but also in the maladaptive ventricular responses and extracellular changes predisposing to adverse outcomes in this population. Expertise in the applications, strengths, and pitfalls of these cardiovascular imaging techniques as they relate to CHD is essential. The purpose of this article is to provide an overview of cardiovascular imaging in CHD. We focus on the role of 3 widely used noninvasive imaging techniques in CHD—echocardiography, cardiac magnetic resonance imaging, and cardiac computed tomography. Consideration is given to the common goals of cardiac imaging in CHD, including assessment of structural and residual heart disease before and after surgery, quantification of ventricular volume and function, stress imaging, shunt quantification, and tissue characterization. Extracardiac imaging is highlighted as an increasingly important aspect of CHD care.

Fetal Diagnosis of Abnormal Origin of the Left Pulmonary Artery

Isolated anomalies of the branch pulmonary arteries are rare, more often occurring in the setting of complex congenital heart disease. These isolated anomalies are often not identified in the prenatal period. We describe two cases of isolated anomalies of the left pulmonary artery which were identified on fetal echocardiography and confirmed postnatally, an anomalous left pulmonary artery arising from the base of the left‐sided brachiocephalic artery in the setting of a right‐sided aortic arch, and a left pulmonary artery sling. These two cases support our current understanding of normal and abnormal development of the extrapericardial arterial vessels and highlight the importance of meticulous attention when sweeping from the three‐vessel tracheal view.

Variations in rotation of the aortic root and membranous septum with implications for transcatheter valve implantation

Objective It is intuitive to suggest that knowledge of the variation in the anatomy of the aortic root may influence the outcomes of transcatheter implantation of the aortic valve (TAVI). We have now assessed such variation. Methods We used 26 specimens of normal hearts and 78 CT data sets of adults with a mean age of 64±15 years to measure the dimensions of the membranous septum and to assess any influence played by rotation of the aortic root, inferring the relationship to the atrioventricular conduction axis. Results The aortic root was positioned centrally in the majority of both cohorts, although with significant variability. For the cadaveric hearts, 14 roots were central (54%), 4 clockwise-rotated (15%) and 8 counterclockwise-rotated (31%). In the adult CT cohort, 44 were central (56%), 21 clockwise-rotated (27%) and 13 counterclockwise-rotated (17%). A mean angle of 15.5° was measured relative to the right fibrous trigone in the adult CT cohort, with a range of −32° to 44.7°. The dimensions of the membranous septum were independent of rotation. Fibrous continuity between the membranous septum and the right fibrous trigone increased with counterclockwise to clockwise rotation, implying variation in the relationship to the atrioventricular conduction axis. Conclusions The central fibrous body is wider, providing greater fibrous support, in the setting of clockwise rotation of the aortic root. Individuals with this pattern may be more vulnerable to conduction damage following TAVI. Knowledge of such variation may prove invaluable for risk stratification.

Pulmonary Atresia With an Intact Ventricular Septum: Preoperative Physiology, Imaging, and Management:

Pulmonary atresia with intact ventricular septum (PA-IVS) is a rare complex cyanotic congenital heart disease with heterogeneous morphological variation. Prenatal diagnosis allows for developing a safe plan for delivery and postnatal management. While transthoracic echocardiography allows for detailed delineation of the cardiac anatomy, additional imaging modalities such as computed tomography, magnetic resonance imaging, and catheterization may be necessary to further outline features of the cardiac anatomy, specifically coronary artery anatomy. The size of the tricuspid valve and right ventricular cavity as well as the presence of right ventricle–dependent coronary circulation help to dichotomize between biventricular repair versus univentricular palliation or heart transplantation, as well as predicting the expected survival. The delineation and understanding of these features help to dictate both medical and surgical management.