Molecular and Genetic Insights into Thoracic Aortic Dilation in Conotruncal Heart Defects

Growth of the Neo-Aortic Root and Prognosis of Transposition of the Great Arteries

BACKGROUND

Neo-aortic root dilatation can lead to significant late morbidity after the arterial switch operation (ASO) for dextro-transposition of the great arteries (d-TGA).

OBJECTIVES

We sought to examine the growth of the neo-aortic root in d-TGA.

METHODS

A single-center, retrospective cohort study of patients who underwent the ASO between July 1, 1981 and September 30, 2022 was performed. Morphology was categorized as dextro-transposition of the great arteries with intact ventricular septum (d-TGA-IVS), dextro-transposition of the great arteries with ventricular septal defect (d-TGA-VSD), and double-outlet right ventricle-transposition of the great arteries type (DORV-TGA). Echocardiographically determined diameters and derived z scores were measured at the annulus, sinus of Valsalva, and sinotubular junction immediately before the ASO and throughout follow-up. Trends in root dimensions over time were assessed using linear mixed-effects models. The association between intrinsic morphology and the composite of moderate-severe aortic regurgitation (AR) and neo-aortic valve or root intervention was evaluated with univariable and multivariable Cox proportional hazards models.

RESULTS

Of 1,359 patients who underwent the ASO, 593 (44%), 666 (49%), and 100 (7%) patients had d-TGA-IVS, d-TGA-VSD, and DORV-TGA, respectively. Each patient underwent a median of 5 echocardiograms (Q1-Q3: 3-10 echocardiograms) over a median follow-up of 8.6 years (range: 0.1-39.3 years). At 30 years, patients with DORV-TGA demonstrated greater annular (P < 0.001), sinus of Valsalva (P = 0.039), and sinotubular junction (P = 0.041) dilatation relative to patients with d-TGA-IVS. On multivariable analysis, intrinsic anatomy, older age at ASO, at least mild AR at baseline, and high-risk root dilatation were associated with moderate-severe AR and neo-aortic valve or root intervention at late follow-up (all P < 0.05).

CONCLUSIONS

Longitudinal surveillance of the neo-aortic root is warranted long after the ASO.

Natural History of Truncal Root Dilatation and Truncal Valve Regurgitation in Truncus Arteriosus

BACKGROUND

The natural history of the dilated truncal root in repaired truncus arteriosus (TA) is incompletely understood.

METHODS

A single-center review of patients who underwent TA repair between January 1984 and December 2018 was performed. Echocardiographically determined root diameters and derived z scores were measured at the annulus, sinus of Valsalva (SoV), and sinutubular junction (STJ) immediately before TA repair and throughout follow-up. Linear mixed-effects models assessed trends in root dimensions over time.

RESULTS

Of 193 patients who underwent TA repair at a median age of 12 days (interquartile range, 6-48 days) and survived to discharge, 34 (17.6%), 110 (57.0%), and 49 (25.4%) patients had bicuspid, tricuspid, and quadricuspid truncal valves, respectively. Median postoperative follow-up was 11.6 years (interquartile range, 4.4-22.0 years; range, 0.1-34.8 years). Truncal valve or root intervention was required in 38 patients (19.7%). The mean rates of annular, SoV, and STJ growth were 0.7 ± 0.3 mm/y, 0.8 ± 0.5 mm/y, and 0.9 ± 0.4 mm/y, respectively. Root z scores remained stable with time. At baseline, compared with patients with tricuspid leaflet anatomy, bicuspid patients had larger diameters at the SoV (P = .003) and STJ (P = .029), whereas quadricuspid patients had larger STJ diameters (P = .004). Over time, the bicuspid and quadricuspid cohorts demonstrated comparatively greater annular dilatation (both P < .05). Patients with ≥75th percentile root growth rates had a higher incidence of moderate-severe truncal regurgitation (P = .019) and truncal valve intervention (P = .002).

CONCLUSIONS

Root dilatation in TA persisted for up to 30 years after primary repair. Patients with bicuspid and quadricuspid truncal valves demonstrated greater root dilatation over time and required more valve interventions. Continued longitudinal follow-up is warranted in this higher-risk cohort.

Aortopathy in Congenital Heart Disease

Aortic dilatation is common in patients with congenital heart disease and is seen in patients with bicuspid aortic valve and those with conotruncal congenital heart defects. It is important to identify patients with bicuspid aortic valve at high risk for aortic dissection. High-risk patients include those with the aortic root phenotype and those with syndromic or familial aortopathies including Marfan syndrome, Loeys-Dietz syndrome, and Turner syndrome. Aortic dilatation is common in patients with conotruncal congenital heart defects and rarely results in aortic dissection.

Feasibility of Wave Intensity Analysis in Patients With Conotruncal Anomalies Before and After Pregnancy: New Physiological Insights?

Background: Conotruncal anomalies (CTA) are associated with ongoing dilation of the aortic root, as well as increased aortic stiffness, which may relate to intrinsic properties of the aorta. Pregnancy hormones lead to hemodynamic changes and remodeling of the tunica media, resulting in the opposite effect, i.e., increasing distensibility. These changes normalize post-pregnancy in healthy women but have not been fully investigated in CTA patients. Methods: We examined aortic distensibility and ventriculo-arterial coupling before and after pregnancy using cardiovascular magnetic resonance (CMR)-derived wave intensity analysis (WIA). Pre- and post-pregnancy CMR data were retrospectively analyzed. Aortic diameters were measured before, during, and after pregnancy by cardiac ultrasound and before and after pregnancy by CMR. Phase contrast MR flow sequences were used for calculating wave speed (c) and intensity (WI). A matched analysis was performed comparing results before and after pregnancy. Results: Thirteen women (n = 5, transposition of the great arteries; n = 6, tetralogy of Fallot; n = 1, double outlet right ventricle, n = 1, truncus arteriosus) had 19 pregnancies. Median time between delivery and second CMR was 2.3 years (range: 1-6 years). The aortic diameter increased significantly after pregnancy in nine (n = 9) patients by a median of 4 ± 2.3 mm (range: 2-7.0 mm, p = 0.01). There was no difference in c pre-/post-pregnancy (p = 0.73), suggesting that increased compliance, typically observed during pregnancy, does not persist long term. A significant inverse relationship was observed between c and heart rate (HR) after pregnancy (p = 0.01, r = 0.73). There was no significant difference in cardiac output, aortic/pulmonary regurgitation, or WI peaks pre-/post-pregnancy. Conclusions: WIA is feasible in this population and could provide physiological insights in larger cohorts. Aortic distensibility and wave intensity did not change before and after pregnancy in CTA patients, despite an increase in diameter, suggesting that pregnancy did not adversely affect coupling in the long-term.

Long-term Outcomes of the Arterial Switch Operation for d-Transposition of the Great Arteries

Dextrotransposition of the great arteries (d-TGA) is a relatively rare form of complex childhood congenital heart disease, which occurs in approximately 0.2 in 1000 live births (Long et al, 2010). The most common palliative procedure for this anatomy has become the arterial switch operation (ASO). We will review in this paper the evidence that is currently available regarding the clinical management following the ASO. Individuals with d-TGA who undergo ASO at a young age thus far have excellent long-term outcomes. Long-term complications for the ASO should be monitored for and patients should have routine follow-up with specialists in adult congenital heart disease.

Congenital heart diseases and cardiovascular abnormalities in 22q11.2 deletion syndrome: From well-established knowledge to new frontiers

Congenital heart diseases (CHDs) and cardiovascular abnormalities are one of the pillars of clinical diagnosis of 22q11.2 deletion syndrome (22q11.2DS) and still represent the main cause of mortality in the affected children. In the past 30 years, much progress has been made in describing the anatomical patterns of CHD, in improving their diagnosis, medical treatment, and surgical procedures for these conditions, as well as in understanding the underlying genetic and developmental mechanisms. However, further studies are still needed to better determine the true prevalence of CHDs in 22q11.2DS, including data from prenatal studies and on the adult population, to further clarify the genetic mechanisms behind the high variability of phenotypic expression of 22q11.2DS, and to fully understand the mechanism responsible for the increased postoperative morbidity and for the premature death of these patients. Moreover, the increased life expectancy of persons with 22q11.2DS allowed the expansion of the adult population that poses new challenges for clinicians such as acquired cardiovascular problems and complexity related to multisystemic comorbidity. In this review, we provide a comprehensive review of the existing literature about 22q11.2DS in order to summarize the knowledge gained in the past years of clinical experience and research, as well as to identify the remaining gaps in comprehension of this syndrome and the possible future research directions.