Restrictive right ventricular physiology and right ventricular fibrosis as assessed by cardiac magnetic resonance and exercise capacity after biventricular repair of pulmonary atresia and intact ventricular septum

Current status of transcatheter intervention for complex right ventricular outflow tract abnormalities

Various transcatheter interventions for the right ventricular outflow tract (RVOT) have been introduced and developed in recent decades. Transcatheter pulmonary valve perforation was first introduced in the 1990s. Radiofrequency wire perforation has been the approach of choice for membranous pulmonary atresia in newborns, with high success rates, although complication rates remain relatively common. Stenting of the RVOT is a novel palliative treatment that may improve hemodynamics in neonatal patients with reduced pulmonary blood flow and RVOT obstruction. Whether this option is superior to other surgical palliative strategies or early primary repair of tetralogy of Fallot remains unclear. Transcatheter pulmonary valve replacement has been one of the biggest innovations in the last two decades. With the success of the Melody and SAPIEN valves, this technique has evolved into the gold standard therapy for RVOT abnormalities with excellent procedural safety and efficacy. Challenges remain in managing the wide heterogeneity of postoperative lesions seen in RVOT, and various technical modifications, such as pre-stenting, valve ring modification, or development of self-expanding systems, have been made. Recent large studies have revealed outcomes comparable to those of surgery, with less morbidity. Further experience and multicenter studies and registries to compare the outcomes of various strategies are necessary, with the ultimate goal of a single-step, minimally invasive approach offering the best longer-term anatomical and physiological results.

Prognostic Implications of Right Atrial Dysfunction in Adults With Pulmonary Atresia and Intact Ventricular Septum

Background

Pulmonary atresia with intact ventricular septum is associated with significant morbidity and mortality, but there are limited data to guide risk stratification in this population. The purpose of this study was to assess the role right atrial (RA) strain indices for prognostication in this population.

Methods

This is a retrospective study of adults (aged ≥18 years) with pulmonary atresia with intact ventricular septum and biventricular repair who underwent echocardiogram (2003-2019). RA reservoir strain was used as the primary metric of RA function, and RA dysfunction was defined as RA reservoir strain <31%. Clinical outcomes were assessed using 4 different indices: (1) functional impairment (New York Heart Association II-IV); (2) hepatorenal dysfunction (model for end-stage liver disease excluding international normalized ratio score >11); (3) incident atrial arrhythmias/heart failure hospitalization; (4) heart transplant/cardiovascular death.

Results

Of the 43 patients in the study, RA strain imaging was feasible in 95%, and RA dysfunction was present in 95%. Of the 43 patients, 67% and 49% had functional impairment and hepatorenal dysfunction, respectively; 44% developed incident atrial arrhythmia/heart failure hospitalization and 14% died during follow-up. RA reservoir strain was independently associated with all indices of clinical outcomes.

Conclusion

Collectively, these data suggest that RA strain imaging was feasible in almost all patients and can be used for risk stratification in this population. There was a high prevalence of comorbidities including hepatorenal dysfunction. Further studies are needed to determine the prognostic implications of hepatorenal dysfunction (a previously unrecognized complication), and whether using RA function indices for clinical decision making will lead to improved outcomes in this population.

Systemic Venous Hypertension and Low Output Are Prevalent at Catheterization in Adults with Pulmonary Atresia and Intact Ventricular Septum Regardless of Repair Strategy

Patients with pulmonary atresia and intact ventricular septum (PA-IVS) require intervention early in life, and most survive to a definitive procedure of either Fontan circulation or right ventricle to pulmonary artery (RV-PA) repair. It remains unknown how surgical strategy impacts hemodynamics and comorbidities in adults. Retrospective analysis of adults (age ≥18 years) with PA-IVS undergoing hemodynamic catheterization at Mayo Clinic, MN between January 2000 through January 2020 was performed. 14 patients in the RV-PA group (71% biventricular, 29% 1.5 ventricle repair) and 19 post-Fontan patients [9 lateral tunnel (48%), 6 atriopulmonary (32%), and 4 extracardiac (21%)] were identified. Median age was 29 (21, 34) years. There were no differences in demographics and laboratory data (including MELD-XI) between groups. All patients assessed for liver disease had evidence of hepatic congestion or cirrhosis (14 in the Fontan group and 4 in the RV-PA group). Invasive hemodynamics were comparable between groups with the Fontan and RV-PA groups having similar systemic venous pressure (15.7±4.4 vs. 14.3±6.2, p = .44) and cardiac output (2.2±0.6 vs. 2.0±0.4 L/min/m², p = .23). There was no difference in transplant-free survival (p = .92; 5-year transplant-free survival RV-PA 84%, Fontan 80%). Hemodynamic derangements, namely elevated systemic venous pressure and low cardiac output, are prevalent in patients with PA-IVS undergoing cardiac catheterization regardless of surgical strategy.

Interplay between right atrial function and liver stiffness in adults with repaired right ventricular outflow obstructive lesions

AIMS

This study determined the associations between right atrial (RA) and right ventricular (RV) mechanics and liver stiffness in adults with repaired tetralogy of Fallot (TOF), pulmonary atresia with intact ventricular septum (PAVIS), and pulmonary stenosis (PS).

METHODS AND RESULTS

Ninety subjects including 26 repaired TOF, 24 PAIVS, and 20 PS patients and 20 controls were studied. Hepatic shear wave velocity and tissue elasticity (E), measures of liver stiffness, were assessed by two-dimensional shear wave elastography, while RA and RV mechanics were assessed by speckle tracking echocardiography. Deformation analyses revealed worse RV systolic strain and strain rate, and RA peak positive and total strain, and strain rates at ventricular systole and at early diastole in all of the patient groups compared with controls (all P < 0.05). Compared with controls, all of the patient groups had significantly greater shear wave velocity and hepatic E-value (all P < 0.05). Shear wave velocity and hepatic E-value correlated negatively with RV systolic strain rate, and RA positive strain, total strain, and strain rate at ventricular systole and at early diastole (all P < 0.05). Multivariate analyses revealed RA strain rate at early diastole (P = 0.015, P < 0.001), maximum RA size (P < 0.001, P < 0.001), and severity of pulmonary regurgitation (P = 0.05, Pp = 0.014) as significant correlates of shear wave velocity and hepatic E-value.

CONCLUSION

In adults with repaired TOF, PAIVS, and PS, RA dysfunction and pulmonary regurgitation are associated with liver stiffness.

Late adverse events in patients with pulmonary atresia intact ventricular septum after valvuloplasty

BACKGROUND

We aimed to explore the relationship between temporal right heart growth and long-term outcomes in patients with pulmonary atresia with intact ventricular septum (PA/IVS) who underwent balloon pulmonary valvulopalsty (BPV).

METHODS

Echocardiography was performed to measure the pulmonary valve diameter (PVD), the right atrial end-systolic area (RAA), and the right ventricular end-diastolic area (RVA) before BPV, 1 and 5 years after BPV. The primary and secondary endpoints were to explore temporal changes in the right heart structures and to determine echocardiographic parameters related to late adverse events (LAEs).

RESULTS

In 31 patients, PVD significantly increased after BPV, whereas TVD remained unchanged throughout the follow-up period of 9.1 (5.7-12.0) years. After BPV, RAA temporally decreased, whereas RVA significantly increased. There were six LAEs (19%); arrhythmias in two, heart failure in one, reintervention of the right ventricular outflow tract in one, and reintervention for residual cyanosis in two. The rate of freedom from LAEs at 5 and 10 years were 92% and 82%, respectively. RAA temporally decreased in patients without LAEs (P<0.01); however, RAA remained unchanged throughout the period in patients with LAEs (P=0.16). Moderate or severe pulmonary regurgitation (PR) (hazard ratio [HR], 23.0; 95% confidence interval [CI], 1.3-385; P=0.03) and the ratio of RVA /RAA at 1 year after BPV (HR, 6.3×10^-11; 95%CI, 2.1×10^-20-0.19; P=0.03) were independent risk factors for LAEs.

CONCLUSIONS

Disproportional right heart growth was observed in patients with PA/IVS after BPV. PR and increased RAA are crucial in identifying the burden of LAEs among them.

Single-Cell Transcriptomics of Engineered Cardiac Tissues From Patient-Specific Induced Pluripotent Stem Cell-Derived Cardiomyocytes Reveals Abnormal Developmental Trajectory and Intrinsic Contractile Defects in Hypoplastic Right Heart Syndrome

Background

To understand the intrinsic cardiac developmental and functional abnormalities in pulmonary atresia with intact ventricular septum (PAIVS) free from effects secondary to anatomic defects, we performed and compared single‐cell transcriptomic and phenotypic analyses of patient‐ and healthy subject–derived human‐induced pluripotent stem cell–derived cardiomyocytes (hiPSC‐CMs) and engineered tissue models.

Methods and Results

We derived hiPSC lines from 3 patients with PAIVS and 3 healthy subjects and differentiated them into hiPSC‐CMs, which were then bioengineered into the human cardiac anisotropic sheet and human cardiac tissue strip custom‐designed for electrophysiological and contractile assessments, respectively. Single‐cell RNA sequencing (scRNA‐seq) of hiPSC‐CMs, human cardiac anisotropic sheet, and human cardiac tissue strip was performed to examine the transcriptomic basis for any phenotypic abnormalities using pseudotime and differential expression analyses. Through pseudotime analysis, we demonstrated that bioengineered tissue constructs provide pro‐maturational cues to hiPSC‐CMs, although the maturation and development were attenuated in PAIVS hiPSC‐CMs. Furthermore, reduced contractility and prolonged contractile kinetics were observed with PAIVS human cardiac tissue strips. Consistently, single‐cell RNA sequencing of PAIVS human cardiac tissue strips and hiPSC‐CMs exhibited diminished expression of cardiac contractile apparatus genes. By contrast, electrophysiological aberrancies were absent in PAIVS human cardiac anisotropic sheets.

Conclusions

Our findings were the first to reveal intrinsic abnormalities of cardiomyocyte development and function in PAIVS free from secondary effects. We conclude that hiPSC‐derived engineered tissues offer a unique method for studying primary cardiac abnormalities and uncovering pathogenic mechanisms that underlie sporadic congenital heart diseases.

Tricuspid Regurgitation in Adults after Repair of Right Ventricular Outflow Obstructive Lesions

We determined the prevalence and factors associated with tricuspid regurgitation (TR) in adults with repair of right ventricular (RV) outflow obstruction. A total of 256 patients (128 males) were studied at 25.7 ± 7.2 years after surgery, of whom 179 had repaired tetralogy of Fallot (TOF), 31 had pulmonary atresia with intact ventricular septum (PAIVS), and 46 had pulmonary stenosis (PS). The mitral and tricuspid annulus diameters, maximum right atrial (RA) area, RV end-systolic and end-diastolic areas, and tricuspid and pulmonary regurgitation were assessed using echocardiography. The prevalence of moderate-to-severe TR was 20.7%. Subgroup analysis revealed that prevalence was greater in patients with repaired TOF (20.7%) and PAIVS (35.5%) than PS patients (10.9%). As a group, severity of TR was found to be correlated with RA area (r = 0.35, p < 0.001), RV end-diastolic (r = 0.28, p < 0.001) and end-systolic (r = 0.22, p = 0.001) areas, and tricuspid valve annulus diameter (r = 0.15, p = 0.022). Moderate-to-severe TR was associated with development of cardiac arrhythmias with an odds ratio of 2.9 (95% CI 1.1 to 8.1, p = 0.031). Multivariate analysis revealed maximum RA area (β = 0.36, p = 0.016) as an independent determinant of severity of TR. Moderate-to-severe TR occurs in about one-fifth of adults with repaired TOF, PAVIS, and PS and is associated with RA dilation and risk of development of cardiac arrhythmias.

Fifty-Five Years Follow-Up of 111 Adult Survivors After Biventricular Repair of PAIVS and PS

There is paucity of long-term data on adult survivors after biventricular repair of pulmonary atresia with intact ventricular septum (PAIVS) and pulmonary stenosis (PS). This study aimed to determine the cardiac and non-cardiac outcomes of adult survivors after biventricular repair of PAIVS and PS. The cardiac, neurodevelopmental and liver problems of 111 adults, 40 with PAIVS and 71 with PS, were reviewed. The median follow-up duration of our patients was 26.5 years (range 14.8-55 years). The freedom from reintervention at 30 years was 17.4% and 73.3% for PAIVS and PS patients (p < 0.001), respectively. Compared with PS patients, PAIVS patients had significantly greater prevalence of right atrial and right ventricular (RV) dilatation, and moderate to severe tricuspid and pulmonary regurgitation (all p < 0.05), and cardiac arrhythmias (22.5% vs. 8.5%, p = 0.047). The freedom from development of cardiac arrhythmias at 30 years of 68.4% and 91.6%, respectively, in PAIVS and PS patients (p = 0.03). Cox proportional hazards model identified PAIVS as an independent risk factor for reintervention (HR 4.0, 95% CI 2.1-7.6, p < 0.001) and development of arrhythmias (HR 4.1, 95% CI 1.1-14.4, p = 0.03). Neurodevelopmental problems were found in 17.5% of PAIVS patients and 7.0% of PS patients (p = 0.11). Liver problems occurred in 2 (5%) PAIVS patients, both of whom required conversion to 1.5 ventricular repair. In conclusion, long-term problems, including the need for reinterventions, cardiac arrhythmias, RV dilation, pulmonary regurgitation, and neurodevelopmental and liver issues are more prevalent in adult PAIVS than PS survivors.

Restrictive right ventricular performance assessed by cardiac magnetic resonance after balloon valvuloplasty of critical pulmonary valve stenosis

BACKGROUND

Little data are published about right ventricular diastolic performance in patients with critical pulmonary valve stenosis after balloon pulmonary valvuloplasty thus far.

METHODS

A total of 44 patients with isolated critical pulmonary valve stenosis who had undergone balloon valvuloplasty with haemodynamic recordings were enrolled to the study; 33 patients who came for follow-up underwent further imaging by echocardiography after 6 months and their right ventricular functional parameters were compared with 33 control patients of the same age and sex. Out of 33 patients, 21 underwent cardiac MRI with late gadolinium enhancement to assess the presence of right ventricular fibrosis.

RESULTS

The right ventricular systolic pressure (p<0.0001) and right ventricular outflow tract gradient (p<0.0001) decreased acutely (p<0.0001) after balloon valvuloplasty. During follow-up, M-mode left ventricular end diastolic dimension (p<0.001) and end systolic dimension increased (p<0.001), whereas right ventricular end diastolic dimension decreased (p<0.001). Compared with controls, patients (n=33) had significantly reduced tricuspid annular Ea and higher E/Ea (p<0.001). Right ventricular systolic dysfunction was also suggested by reduced tricuspid annular systolic velocity (p<0.001). Late gadolinium enhancement was demonstrated in 13 out of 21 patients with restrictive physiology, which involves the anterior right ventricular outflow tract, anterior wall, and inferior wall. The right ventricular late gadolinium enhancement score correlated positively with age (r=0.7, p<0.001) and right ventricular mass index (r=0.52, p<0.001).

CONCLUSION

The persistence of right ventricular diastolic dysfunction after relief of chronic pressure overload of critical pulmonary valve stenosis suggests that a factor - other than increase in afterload - is involved in this physiology. Fibrosis is the most likely factor responsible for persistence of restrictive physiology as documented by late gadolinium enhancement.

Myocardial iron load and fibrosis in long term survivors of childhood leukemia

BACKGROUND

We sought to assess myocardial iron load and fibrosis, which may potentially affect cardiac function, in adult survivors of childhood leukemias and their relationships with left (LV) and right ventricular (RV) function.

PROCEDURE

Fifty-eight (33 males) adult survivors, aged 24.5 ± 4.4, underwent cardiac magnetic resonance (CMR) at 16.6 ± 5.8 years after completion of treatment. Myocardial iron load and fibrosis were quantified using respectively T2* scan and late gadolinium enhancement. Right and left ventricular ejection fraction (EF) was measured by CMR, while myocardial function was assessed using tissue Doppler imaging.

RESULTS

None of the survivors had significant myocardial iron overload (T2*<20 msec). The prevalence of LV and RV fibrosis was 9% (5/58) and 38% (22/58), respectively. Left ventricular EF was subnormal (EF 45-<55%) in 9% (5/58), while RV EF was abnormal (EF <45%) in 12% (7/58) and subnormal in 34% (20/58) of survivors. Patients with LV fibrosis had significantly lower mitral annular early diastolic velocity (P = 0.01) and smaller LV end-systolic volume (P = 0.02), while those with RV fibrosis had significantly lower tricuspid late diastolic annular velocity (P = 0.02) and early to late diastolic annular velocity ratio (P = 0.02) compared to those without. Cumulative anthracycline dose correlated with early diastolic mitral (r = -0.28, P = 0.038) and tricuspid (r = -0.40, P = 0.002) annular velocities, but not LV and RV EF or fibrosis (all P > 0.05).

CONCLUSION

Ventricular fibrosis may occur in long term survivors of childhood leukemias and is related to diastolic function in the absence of significant myocardial iron overload.

Functional assessment for congenital heart disease

Significant improvement in survival of children with congenital cardiac malformations has resulted in an increasing population of adolescent and adult patients with congenital heart disease. Of the long-term cardiac problems, ventricular dysfunction remains an important issue of concern. Despite corrective or palliative repair of congenital heart lesions, the right ventricle, which may be the subpulmonary or systemic ventricular chamber, and the functional single ventricle are particularly vulnerable to functional impairment. Regular assessment of cardiac function constitutes an important aspect in the long-term follow up of patients with congenital heart disease. Echocardiography remains the most useful imaging modality for longitudinal monitoring of cardiac function. Conventional echocardiographic assessment has focused primarily on quantification of changes in ventricular size and blood flow velocities during the cardiac cycles. Advances in echocardiographic technologies including tissue Doppler imaging and speckle tracking echocardiography have enabled direct interrogation of myocardial deformation. In this review, the issues of ventricular dysfunction in congenital heart disease, conventional echocardiographic and novel myocardial deformation imaging techniques, and clinical applications of these techniques in the functional assessment of congenital heart disease are discussed.

Guidelines and protocols for cardiovascular magnetic resonance in children and adults with congenital heart disease: SCMR expert consensus group on congenital heart disease

Cardiovascular magnetic resonance (CMR) has taken on an increasingly important role in the diagnostic evaluation and pre-procedural planning for patients with congenital heart disease. This article provides guidelines for the performance of CMR in children and adults with congenital heart disease. The first portion addresses preparation for the examination and safety issues, the second describes the primary techniques used in an examination, and the third provides disease-specific protocols. Variations in practice are highlighted and expert consensus recommendations are provided. Indications and appropriate use criteria for CMR examination are not specifically addressed.

Late clinical features of patients with pulmonary atresia or critical pulmonary stenosis with intact ventricular septum after biventricular repair

BACKGROUND

We aimed to reveal late clinical features of patients with pulmonary atresia with intact ventricular septum (PA/IVS) or critical pulmonary stenosis (cPS) after biventricular repair (BVR) based on preoperative right ventricular (RV) end-diastolic volume (RVEDV) findings.

METHODS

Since 1985, 23 of 73 patients with PA/IVS (n=22) or cPS (n=1) with a tripartite RV and without major sinusoidal communication underwent BVR with a hybrid approach. The mean age and weight at BVR were 1.4±2.1 years and 6.9±5.9 kg, respectively. Mean follow-up was 10.1±6.4 years (range, 1.1 to 24.6 years).

RESULTS

Overall survival, reintervention-free, and arrhythmia-free rates at 20 years were 90.6%, 75.4%, and 50.4%, respectively. In 19 patients with preoperative RVEDV of 60% to 120% of normal, echocardiography at 10 years after BVR showed well-maintained RV systolic function. However, RV volume was quantitatively dilated in 16 (88.9%) due to moderate or greater tricuspid regurgitation in 8 (44.4%), pulmonary regurgitation in 12 (66.7%), or both, which caused arrhythmia in 3 patients more than 10 years after BVR. Two patients with preoperative RVEDV of greater than 120% of normal required tricuspid valve replacement after BVR, after which refractory atrial tachyarrhythmia developed in both patients. Furthermore, 2 patients with preoperative RVEDV of less than 60% of normal showed a cardiac index value within 2.5 L/min/m2 at 1 year after BVR, which did not improve.

CONCLUSIONS

Patients with PA/IVS or cPS and adequately sized RV showed good late clinical features after BVR. However, long-term follow-up examinations are necessary for RV dilatation and late-onset arrhythmia.