The trends and patterns of congenital heart diseases at Madinah Cardiac Center, Madinah, Saudi Arabia

Discussion

Studies determining the prevalence and incidence rates of CHDs have been conducted for decades throughout the world. To calculate the true incidence or prevalence rate of a disease requires an accurate diagnosis in all affected individuals in the area where the study was conducted. However, as mentioned earlier, it is not possible to determine the correct rate as many cases of children with CHDs are either under reported due to premature death without a diagnosis, or overestimated due to the inclusion of trivial lesions which heal spontaneously or do not cause significant morbidity or mortality in the affected children. The present work was a retrospective study conducted at a tertiary referral hospital for cardiac diseases in the Madinah region of Saudi Arabia. Thus, it cannot reflect the true incidence rate of CHDs in the entire region. Nevertheless, our data reflect the general pattern rather than the true prevalence or incidence rates of CHDs in the Madinah region.

Congenital heart diseases are one of the major contributors to mortality and morbidity in the pediatric age group, and the determination of their rate of occurrence and corresponding burden in a society is vital for the appropriate health policy recommendations and implementations. Research conducted and reported in various surgical series has documented improved survival rates for many CHDs.9 The burden of CHDs is widespread, and each year, at least 1.5 million children are born with CHDs, approximately 90% of these children do not have adequate access to an essential diagnosis or appropriate management, both of which could be life-saving measures for these children.10,11 Ongoing research on CHD has played a vital role in the diagnosis, management, and prevention of the condition. Such studies have also provided insight into gene-specific diagnosis, prognosis, and risks of recurrence. Thus, research in the field of CHD, which emphasizes the trends, epidemiology, and genetic background of the condition, is of great benefit to both patients and society at large. However, research in the field of pediatric cardiology in the Arab world has been relatively limited, and scientific production, activity, and quality are still not at levels comparable with other developed countries.12

Madinah Cardiac Center (MCC) is a tertiary referral center for all cardiac diseases in the Madinah region of Saudi Arabia, catering to an estimated population of 1.5 million people. In our series, a total of 1,127 patients were referred to MCC. Of this, 584 were male with an male to female ratio of 1.1:1, indicating a slight male preponderance. A recent study conducted in 2018 in Nigeria also reported an male to female ratio of 1.1:1.13 However, Asani et al14 from Kano, Nigeria reported an even higher male preponderance of 3:2. Similarly, Meshram and Gajimwar15 from India also found a higher male to female ratio, and they attributed the higher incidence rate of CHD in male children to the cultural norms and male preference in their country. Although most of the studies have reported a male preponderance of CHD, a study from China by Zhao et al16 noted a higher incidence rate in female children with a ratio of 1:1.3, they also emphasized that in their study, the females had milder cases of CHD like PDA, ASD, and VSD, while the males had more severe CHDs like ToF and TGA. In our study, there was a slight male preponderance of overall CHDs, but we also observed the more frequent occurrence of critical CHDs in the male children.

In the present study, children with CHDs presented at an older age with a mean age of 8.4±2.4 years (within a wide range from 3 days to 18 years). A total of 705 children (62.6%) were in the age group of 6–10 years. This observation is different from the data of previous regional, national, and international studies. According to a global study conducted at China,3 50% of CHDs are detected by the age of one month, 75% by 3 months, and almost 100% will be diagnosed by the time that the child is 3-4 years of age. In another study from the United States, the diagnosis of CHD was confirmed by the age of one week in 40-50% of newborns and by one month of age in 50-60% of neonates born with CHDs.7 A similar pattern was observed in a large population-based study from Europe.17 However, a later age of diagnosis has been reported primarily in developing countries where there may be a lack of diagnostic facilities available along with a poor socioeconomic status of the patients.5,18,19 We observed that the mean age of diagnosis in developing countries was much higher, and a proper screening program and early diagnostic facilities must be provided to reduce the mortalities arising from CHDs.

In this study, acyanotic CHDs were found to have a significantly later presentation than cyanotic heart diseases. A similar observation was made by researchers from Nigeria, Yemen, and Pakistan.13,18,19 Contrary to our observation of a later age at diagnosis, the age at which CHD was diagnosed in Saudi Arabia was found to be similar to that of developed nations; previous studies from Saudi Arabia have reported an earlier age of diagnosis, with the majority of patients being diagnosed during the neonatal period of their life.9,20,21 In a recent study from Riyadh conducted by Majeed-Saidan et al,22 a very early age of diagnosis was reported in their investigation of neonates who were diagnosed prenatally during routine antenatal visits, with 62% of the babies being diagnosed during their first week, and only 2.8% being diagnosed between the ages of 1-4 weeks. However, in our study, the later age of diagnosis was not related to those causes mentioned by authors from developing countries; in our case, the later age points to a lack of awareness about the prevalence of CHDs in the general population. Nevertheless, the major reason for the advanced age of presentation in the present study can be mainly attributed to the availability of a full-time, well-functioning pediatric cardiology unit at the maternity and children’s hospital in Madinah, where a majority of births and referrals take place. Hence, many of our patients were either referred from the surrounding localities or did not wish to continue their follow-ups with their previous hospitals. Moreover, the MCC is a tertiary referral hospital with a dedicated pediatric cardiology unit and state-of-the-art diagnostic and therapeutic facilities.

In the present study, 84.8% of cases were acyanotic heart diseases; this observation is well correlated with the previous regional, national, and international findings. Similar observations were noted in a recent article published in 2019 by Kafian et al23 from Iran, who observed that 87% of their cases were acyanotic heart diseases. From the Qassim region of Saudi Arabia, Al-Mesned et al9 observed that many lesions in their study were acyanotic. Saxena et al24 from New Delhi, India also noted that 79.9% of their patients with CHDs had acyanotic heart diseases. While VSD was the most commonly encountered CHD in many previous national and international studies, we reported PDA as the most commonly occurring CHD in our study, which accounted for 27.9% of the total cases. Patent ductus arteriosus usually closes spontaneously within 48 hours of birth, but it still accounts for 5-10% of all CHDs, and is seen most frequently in females; however, in our study, its incidence rate was higher than the rates in previously reported data.20-24 The reason for the higher rate of PDA in this case can be mainly attributed to the referrals to our hospital for surgical correction of significantly large PDAs which were left untreated; another reason could be due to the clinical presentation of PDA, as a majority of cases close spontaneously, and small PDAs usually do not cause any significant signs and symptoms. As mentioned earlier, VSD is the most frequently encountered CHD, and after extensively reviewing the available literature on CHD, we could find only one article on this issue from Iran published in 2008 by Rahim et al,25 who reported that PDA was the most common CHD, accounting for 17.97% of total cases. However, our PDA numbers were significantly higher, which warrants further studies with an emphasis on molecular and genetic research. Although Kafian et al23 from Iran have reported VSD to be the most common lesion, the incidence rate of PDA was next closest to VSD in their cohort and accounted for 18.2% of total cases, which is close to our observation.

The next most common acyanotic CHDs in our study were VSD observed in 24.8% and ASD in 18.9% of total cases. Mohammad et al26 from Pakistan reported 29.9% of their cases were VSD, and 25.4% were with ASD; their observed rates were higher than those of our findings. From the Qassim region, Al-Mesned et al9 reported a similar incidence rate of VSD (22.5%). Zhao et al16 from China also reported that VSD is the most common lesion, followed by ASD and PDA. Another significant acyanotic CHD in our cohort was the CoA, which was seen in 6.4% (71/1,127) of cases. Rahim et al25 reported a lower incidence rate (1.7%) of CoA in their study; similarly, Ekure et al5 from Nigeria and Iyad et al27 from Jordan also reported lower rates of CoA at 4.3% and 2.6%, respectively.

Among the cyanotic CHDs, ToF was the most common lesion in our cohort, which was seen in 97 patients and accounted for 8.7% of all cases. Our result correlated well with the previously reported data of 4.6-18.3%.3 However, Chatterjee et al28 from India reported a higher rate of ToF in their study (21%). The second most common cyanotic CHD in our study was TGA, which was seen in 1.7% of cases, Mohammad et al26 from Pakistan also observed TGA as the second most common cyanotic lesion. A detailed comparison of our findings with previous national and international studies is depicted in Table 3.

This study incorporates most of the available previous publications, thus, making it one of the comprehensive studies on congenital heart disease in our region and shows a substantial burden of the disease. Our data will provide a better information and priorities to the stake holders in the field of health care at national and global level. We believe our data will help in better planning and survival improvement and set a benchmark for the policy making in our country and other neighboring countries.