Clinical characteristics of congenital heart defects in mild congenital anorectal malformation: single-centre experience

CARM is a rare congenital malformation of the gastrointestinal tract characterized by the complete or partial absence of the anorectal canal at birth, with or without a fistula. It is often associated with other system malformations, of which the cardiovascular system is more common. As a rule, a complex form of CARM is evident, and pediatric clinicians preferred to perform thorough screening for these patients [2‐4]. Unfortunately, in case of a mild form of CARM, the screening mostly depends on the clinician preferences, which may be easily overlooked. Thorough screening can identify associated malformations early, help to ensure the safety of surgery, and formulate the optimal treatment plan and postoperative individualized management. Screening for CHD, in particular, is considered the most variable aspect of the diagnostic workup.

The frequency of CHD in CARM cases varies across different research studies. Study from India showed that the frequency of CHD in CARM patients was 50%, and the most common presentation was ASD, followed by VSD and PDA [24]. But another study reported that the frequency of CHD in CARM patients was 22%, and the most frequent defect was VSD [25]. Regarding the frequency of CHD in mild CARM patients, Jonker JE et al. reported that it was 16%, of which 9% were diagnosed as minor CHD and 7% were diagnosed as major CHD [20]. In our study, the frequency of CHD in mild CARM patients was 79.8%, which is significantly higher than that reported in other studies. This may be due to the fact that we always insist on performing echocardiography screening for every patient with CARM to avoid as many missed diagnoses as possible, whether it’s a complex or a mild CARM. However, none of these studies conducted a distinction between different types of mild CARM. In our study, we observed that the highest frequency of specific CHD was ASD, both in patients with rectovestibular and rectoperineal fistulas, accounting for 53.4% and 50.0%, respectively. Patients with rectoperineal fistula had a higher probability of developing PDA, while patients with rectovestibular fistula were more prone to VSD. Several studies have demonstrated a significantly higher frequency of CHD in CARM patients compared to the general population [17, 22, 26]. The presence and severity of CHD affect the choice of surgical methods and timing not only for mild CARM, but also for complex form [27, 28]. For rectoperineal fistula, we chose the following surgical method based on the presence and severity of CHD: (1) no or minor CHD: cutback anoplasty with or without mobilized the rectum end inside the center of sphincter; (2) major CHD: routine dilations of the fistula to permit egress of stool (typically Hegar size > 5 mm) and then delayed repair with cutback anoplasty. For rectovestibular fistula, the following principles are our preference: (1) no or minor CHD: modified posterior sagittal anorectoplasty (saving the perineal body); (2) major CHD: routine dilations of the fistula to permit egress of stool and then delayed repair with modified posterior sagittal anorectoplasty, or three-staged repair (transverse-loop colostomy, modified posterior sagittal anorectoplasty, and colostomy) for those abdominal distension not relieved after anal dilatation. Consequently, we recommend the routine utilization of color Doppler echocardiography in mild CARM patients to assess the presence and severity of CHD and to ensure the safety of surgical procedure and postoperative care.

Previous population-based study has documented the presence of sexual dimorphism in various forms of CHD, with a higher prevalence of ASD and ASD in females, while a male predominance in aortic stenosis, coarctation of aorta, transposition of the great arteries, TOF, and double outlet right ventricle [29]. Our study found that males had a higher likelihood of having PDA, while no significant differences were observed among the other forms of CHD. Rectovestibular fistula is the most important CARM in females, presenting with the anal opening is located in the vestibule of the female genitalia, far away from the anal sphincter [7]. Considering that all cases of rectovestibular fistula were observed exclusively in females, our subgroup analysis of rectoperineal fistula revealed that no sex differences existed between the types of CHD. These findings suggest that there is no sex disparity in the types of mild CARM associated with CHD, a finding that has not been previously reported in other studies.

There are few studies on the diagnosis age of CHD in mild CARM patients, and our study showed that the diagnosis age of CHD ranged from 0 to 67 days, with 119 cases (65%) diagnosed within 1 week and 165 cases (90.2%) diagnosed within 1 month. Furthermore, the diagnosis age of CHD tends to be higher in females compared to males, and this trend was also observed in the subgroup analysis of rectoperineal fistula. However, there was no statistical difference in the diagnosis age of CHD between rectovestibular fistula and rectoperineal fistula in females. It means that there is a correlation between diagnosis age and sex, but not the specific type of mild CARM. This phenomenon could potentially be attributed to the timing of mild CARM diagnosis, as patients typically do not undergo routine echocardiography at birth and are usually assessed for CHD when mild CARM is detected or when they are hospitalized for symptoms associated with mild CARM. Complex CARM encompasses various types of lesions, and the absence of an anal opening in the anal crypt is easily identifiable at birth. However, most mild CARM patients often do not exhibit prominent symptoms apart from chronic constipation, and inexperienced physicians may overlook mild CARM, resulting in delayed diagnosis [30‐32]. This study did not compare CHD among those with complex CARM as it was beyond the scope of this study. We are not aware if males exhibit more pronounced and earlier clinical manifestations compared to females [33]. However, it is important to note that this is merely speculative and requires further investigation through subsequent studies.

The self-healing rate of CHD was 66.4% at 6 months and 78.1% at 12 months in our study. Notably, these rates were found to be significantly higher in males compared to females. Furthermore, females had significantly higher rate of undergoing cardiac surgery compared to males. These results are consistent with the European Heart Survey database of adult CHD, which suggests that females may have a higher prevalence of limited cardiac function compared to males, possibly related to hormone level [34, 35]. Based on the observation that females tend to receive a diagnosis of CHD at a later age compared to males, and exhibit lower rates of self-healing at 6 and 12 months, we propose the implementation of enhanced cardiac evaluation and closer monitoring for females with mild CARM. It is widely accepted that minor CHD is more likely to heal spontaneously compared to major CHD, and this is supported by our study, although not statistically significant, which may be due to inadequate sample size. Analysis of cardiac surgery rates in patients with different severity of CHD showed that the surgery rate in patients with major CHD was significantly higher than that in patients with minor CHD, aligning with our anticipated results. Additional, the self-healing rates of CHD at 6 months and 12 months in patients with rectovestibular fistulas were significantly lower than that in patients with rectovaginal fistula, but there was no correlation between cardiac surgery rates. It also indicates that there is a necessity for exceptional cardiac assessment and follow-up in females with mild CARM.

It’s known that severe CHD often coexists with MCD. Study indicates that up to 70% of patients with CARM also exhibit malformations in other bodily systems [36]. Recently, it has been reported that CARM patients with extracardiac malformations have a notable frequency of combined severe CHD, with each additional extracardiac malformation increasing the probability of severe CHD by 3.85 times [37]. Similar results were obtained in this study, that the frequency of MCD was not associated with a specific type of mild CARM or sex, but with the presence of CHD. Specifically, the prevalence of MCD was observed to be 39% and 26.6% in patients with major and minor CHDs, respectively. Although statistical significance was not achieved, a discernible trend is apparent, potentially attributable to the limited size of our sample.

To further provide early and thorough screening for suspicious or confirmed neonates, we have established a circular linkage mechanism with hospitals at all levels to enable timely referral to our hospital if malformations are detected. Currently, our hospital actively participates in the construction of regional medical consortia, and carries out prenatal screening of CARM utilizing telemedicine cloud platform in collaboration with obstetrics department. Then, for suspicious cases, pediatricians provide perinatal professional consultation to the family numbers with the help of “Internet +” technology, and carried out seamless referral of confirmed cases after delivery [38]. Overall, by collecting comprehensive clinical data, conducting specialized echocardiography, and following standardized treatment processes, it helps to to provide the best possible care and outcomes for these patients.