Two-Dimensional and Real-Time Three-Dimensional Echocardiographic Fetal Diagnosis of Aorto-Ventricular Tunnel

The aorto-left ventricular tunnel from a fetal perspective: original case series and literature review

Introduction

Aorto‐left ventricular tunnel (ALVT) accounts for <0.1% of congenital heart defects. Evidence on the prognosis from a fetal perspective is limited. With this retrospective international case series, we provide information on the outcome of fetuses with ALVT.

Methods

All members of the Association for European Pediatric and Congenital Cardiology's (AEPC) fetal working group and fetal medicine units worldwide were invited for participation. We observed antenatal parameters, neonatal outcome and postnatal follow‐up. Additionally, a systematic search of the literature was performed.

Results

Twenty fetuses with ALVT were identified in 10 participating centers (2001–2019). Fetal echocardiographic characteristics of ALVT included an increased cardiac–thorax ratio (95%), left ventricular end‐diastolic diameter (90%) and a dysplastic aortic valve (90%). Extracardiac malformations were rare (5%). Eight fetuses died at a median gestational age (GA) of 21 + 6 weeks (range, 19–24): all showed signs of hydrops prior to 24 weeks or at autopsy. All others (60%, 12/2) were live–born (median GA 38 + 4, range 37–40), underwent surgery and were alive at last follow up (median 3.2 years, range 0.1–17). The literature reported 22 ALVT fetuses with similar outcome.

Conclusions

In the absence of fetal hydrops, ALVT carries a good prognosis. Fetuses who survive to 24 weeks without hydrops are likely to have a good outcome.

What's already known about this topic?

Aorto‐left ventricular tunnel (ALVT) is an extremely rare diagnosis that may cause congenital heart failure and fetal hydrops, leading to fetal or neonatal death.

A few case reports show that after corrective surgery in the neonatal period, cases with ALVT tend to have a good prognosis.

What does this study add?

This is the first study that evaluates prenatal characteristics, prognostic parameters and outcome following a prenatal diagnosis of ALVT in a cohort of cases worldwide, including a systematic review of the literature as well.

In the absence of fetal hydrops, ALVT carries a good prognosis. Fetuses who survive to 24 weeks without hydrops are likely to have a good outcome.

A Review of the Surgical Management of Aorto-ventricular Tunnels

We present a synthesis of 95 published investigations of the exceedingly rare tunnels that can exist between the aortic root and the left or right ventricles. From the 220 suitable cases included in these investigations, we reviewed the clinical presentations, modalities used for diagnosis, surgical approaches, and outcomes. Diagnostic information was provided by clinical presentation, radiographic findings, saline contrast echocardiography, computed tomographic angiocardiography, magnetic resonance imaging, cardiac catheterization, and angiocardiography. These techniques elucidated the coronary arterial origins and associated defects and defined the disease before surgery. Patients occasionally present with an asymptomatic cardiac murmur and cardiomegaly, but most suffer cardiac failure in the first year of life when the tunnel enters the left ventricle. Antenatal diagnosis by fetal echocardiography is reliable after 18 weeks of gestation. Associated defects, involving the proximal coronary arteries or the aortic or pulmonary valves, are present in nearly half the cases. Prompt diagnosis and surgical repair are important for a favorable outcome. Overall, operative mortality has been cited to be between 3% and 8.3%. Associated congenital coronary arterial anomalies, residual severe aortic stenosis, poor left ventricular function, and rupture of an infected suture line have been the reported causes of death. Despite early surgical intervention, an incidence of 16% to 60% postoperative residual aortic regurgitation of varying severity has been reported. The requirement of further repair or replacement of the aortic valve ranges from 0% to 50%. We submit that an increased appreciation of these details relative to the tunnels will contribute to improved surgical management.

Prenatal Diagnosis of Aorto-Left Ventricular Tunnel With Dysplastic Bicuspid Aortic Valve: From Fetal Cardiac Failure to Favorable Outcome

Aorto-left ventricular tunnel (ALVT) is a rare congenital heart defect. Surgery has to be performed early to avoid life-threatening complications. Prenatal diagnosis of this defect is challenging. We report a case of ALVT diagnosed in a fetus showing premature severe cardiac failure at 24 GA. The new born was operated at day 3 of life with good results. Two years later, he is still doing well recovering a complete normal cardiac function. ALVT should be suggested in front of any fetal cardiac failure. Thanks to early diagnosis, prompt neonatal management can be organized and allows positive outcome.

Congenital aortico-left ventricular tunnel in fetuses and infants

Congenital aortico-left ventricular tunnel (ALVT) is a rare congenital heart disease. A 27-year-old woman was referred to us at 37 weeks gestation with fetal cardiac enlargement. The left ventricle (LV) of the fetus was enlarged. Fetal aortic valve (AoV) ring diameter spread was observed. Back flow from the AoV margins to the LV was observed. The prenatal diagnosis of the fetus was aortic regurgitation (AR). A male neonate was delivered by cesarean section at 40 weeks gestation. We made the diagnosis of ALVT because the aorta and the LV of the neonate showed a tunnel with blood flow on echocardiography. We took another look at the fetal echocardiography. The neonate underwent surgery for exacerbation of heart failure on the 7th day after birth. Trivial flow from the tunnel and mild AR were observed after surgery.

Aortopulmonary window with atrial septal defect: prenatal diagnosis, management and outcome

A case of prenatally diagnosed aortopulmonary window is reported. The mother was referred for fetal echocardiography at 26 weeks' gestation because of suspected congenital heart disease. Prenatal echocardiography showed an aortopulmonary septum defect close to the pulmonary artery bifurcation and a left-to-right shunt flow in systole and early diastole detected by color flow Doppler. Postnatal echocardiography confirmed prenatal diagnosis, the aortopulmonary window was a 9-mm type III aortopulmonary window. An atrial septal defect with shunt flow left to right was also found. Surgical repair was performed 4 weeks after birth, the postsurgical period was uneventful and the newborn was discharged without complications 7 days after surgery.

Aorto-ventricular tunnel

Aorto-ventricular tunnel is a congenital, extracardiac channel which connects the ascending aorta above the sinutubular junction to the cavity of the left, or (less commonly) right ventricle. The exact incidence is unknown, estimates ranging from 0.5% of fetal cardiac malformations to less than 0.1% of congenitally malformed hearts in clinico-pathological series. Approximately 130 cases have been reported in the literature, about twice as many cases in males as in females. Associated defects, usually involving the proximal coronary arteries, or the aortic or pulmonary valves, are present in nearly half the cases. Occasional patients present with an asymptomatic heart murmur and cardiac enlargement, but most suffer heart failure in the first year of life. The etiology of aorto-ventricular tunnel is uncertain. It appears to result from a combination of maldevelopment of the cushions which give rise to the pulmonary and aortic roots, and abnormal separation of these structures. Echocardiography is the diagnostic investigation of choice. Antenatal diagnosis by fetal echocardiography is reliable after 18 weeks gestation. Aorto-ventricular tunnel must be distinguished from other lesions which cause rapid run-off of blood from the aorta and produce cardiac failure. Optimal management of symptomatic aorto-ventricular tunnel consists of diagnosis by echocardiography, complimented with cardiac catheterization as needed to elucidate coronary arterial origins or associated defects, and prompt surgical repair. Observation of the exceedingly rare, asymptomatic patient with a small tunnel may be justified by occasional spontaneous closure. All patients require life-long follow-up for recurrence of the tunnel, aortic valve incompetence, left ventricular function, and aneurysmal enlargement of the ascending aorta.