Aorto-Left Ventricular Tunnel - Prenatal Diagnosis and Outcome

PURPOSE

 Aorto-left ventricular tunnel (ALVT) is an extremely rare, albeit prenatally detectable, extracardiac channel that connects the ascending aorta to the cavity of the left ventricle.

MATERIALS AND METHODS

 All ALVTs diagnosed prenatally (2006-2020) in five tertiary referral centers were retrospectively assessed for prenatal ultrasound findings, intrauterine course, postnatal outcome, and surgical treatment. We focused on the size of the tunnel and alterations of perfusion of the left ventricular outflow tract and aortic arch.

RESULTS

 11 fetuses were diagnosed with ALVT at a mean gestational age of 24.8 weeks. All cases were associated with severe dilatation of the left ventricle and a to-and-fro flow in the left outflow tract. Signs of congestive heart failure were present in five fetuses, four of which were terminated and one of which died in the neonatal period. One fetus died in utero at 34 weeks without prior signs of cardiac failure. Of the five survivors, two underwent the Ross procedure. In both cases the prenatal left ventricular outflow was exclusively via a large tunnel. The remaining three neonates underwent patch closure of the tunnel. In these cases, the prenatal outflow of the left ventricle was via the aortic valve and simultaneously over the tunnel.

CONCLUSION

 Prenatal diagnosis of ALVT should be considered in the presence of left ventricular hypertrophy, dilatation of the aortic root, and to-and-fro flow in the aortic outflow tract. Signs of heart failure are associated with an unfavorable outcome. Large tunnels, particularly in combination with the absence of flow over the aortic valve, may be an unfavorable predictor of surgical repair.

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.

Mid-term outcome of surgical treatment in patients with aorto-left ventricular tunnel

OBJECTIVES

The purpose of this study was to review the outcomes of surgical treatment in patients with aorto-left ventricular tunnel and to investigate what kind of patient cohort is more likely to have adverse events.

METHODS

Twenty-one patients with a median age of 6.58 [interquartile range (IQR) 4.17-24.50] years who received surgical treatment of aorto-left ventricular tunnel from March 2002 to December 2019 were reviewed. The median follow-up time was 64.50 (IQR 25.15-120.50) months. Clinical characteristics, surgical methods and follow-up outcomes were summarized in separate groups of patients with or without preoperative aortic valve (AoV) issues. Composite adverse events were defined as death or requirement of reoperation. Time-related analysis of freedom from death and requirement of reoperation was performed with the Kaplan-Meier method.

RESULTS

The average tunnel size was 8.68 (standard deviation: 3.62) mm. The most common and the most important associated lesions were AoV lesions. Tunnels in 20 patients were closed with direct sutures or a patch. For 1 patient with an irreparable AoV, the tunnel was cut open simultaneously with aortic valve replacement and aortic root plasty. In the group of patients with preoperative AoV issues, 4 patients received aortic valve replacement with mechanical prosthetic valves and 6 patients received aortic valvuloplasty repair. The follow-up outcomes differed significantly between groups (the incidence of death was 15.38% and the incidence of requiring a reoperation was 46.15% in patients with preoperative AoV issues). In the group without preoperative AoV issues, there were no deaths and no reoperations (Fisher's exact test; P = 0.018). The probability of freedom from death and of the requirement for reoperation between the 2 groups was not significantly different (log-rank, P = 0.09). Overall, the estimated probability of freedom from death and requirement of reoperation was 77.30% (standard error: 10.20%) [95% confidence interval (CI): 49.53-91.00] at 5 years, 67.64% (standard error: 12.70%) (95% CI: 36.71-85.84) at 10 years.

CONCLUSIONS

Patients with aorto-left ventricular tunnel with preoperative AoV issues are more prone to die or to require a reoperation. In contrast, patients without preoperative AoV issues can be free from death or reoperation for a longer period of time. Patients with preoperative AoV issues need much stricter postoperative long-term echocardiographic follow-up.

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.