By Gabi Giacomin
Appearing in the Annals of Pediatric Cardiology last year (2017) is a research article questioning the procedure of closing small Ventricular Septal Defects (VSD’s) in children.
The authors claim there is a substantial amount of evidence suggesting a high rate of spontaneous closure of small VSD’s which extends through childhood into adolescence. If pulmonary artery pressures are within limits, the idea of delaying closure seems to be favoured. This gives the patient the best chance of recovering spontaneously, allowing them to participate in decision making regarding whether they would like to have the small VSD closed later in life.
Diagnosing a small VSD seems to be controversial as ‘gradients’ versus ‘size cutoffs’ vary according to different authors. Cohort studies reveal spontaneous closure rates vary from 34% at 12 months of age, 67% at 5 years of age and up to 75% at 10.5 years of age. Follow up evaluation of children between 8.6 years and 16.6 years showed spontaneous closure continued to occur in 24% of cases and VSD diameter decreased from 5.3 – 2.7mm on average.
Small VSDs are considered ‘significant’ and should be closed if associated with left heart volume (LV) loading. LV is difficult to define and can reflect a previously large shunt that is improving or increasing left heart volume open to assessment. According to research, LV dilation noted during childhood appears to improve and normalise during adulthood. There is also no clear evidence linking LV with adverse clinical outcomes.
Infective endocarditis (IE) is one of the important reasons for closing a small VSD, despite the incidence being relatively small (0.1 per 1000 person years). There are several case reports of IE following surgical closure of VSDs. The incidence of IE in untreated patients was 4.3% compared to 2.7% in patients who underwent surgery. Closing a VSD doesn’t appear to reduce the risk of endocarditis, which is low in a population setting. It is suggested that advice regarding dental hygiene would have greater impact in reducing infective endocarditis.
Finally, published literature is full of reports of complications of closures of VSDs, yet most conclude that the ‘risks and complications are within acceptable limits.’ Robust research is necessary to help us understand the balance of risk versus benefit for treatments recommended to our patients.
“There is a substantial body of evidence that suggests a significant rate of spontaneous closure and further restriction of small VSDs, which extends into late childhood and early adolescence. This would favor delaying closure of small VSDs till adolescence or early adulthood (if the pulmonary artery pressures are within normal limits) giving the patient the best chance of spontaneous closure and an opportunity to participate in the decision-making regarding whether they would like to have their small VSD closed.”
“Most available evidence suggests that there is a tendency for left heart dilation to improve with time in patients with small restrictive VSDs. Furthermore, there is no clear evidence in literature linking left heart dilation with adverse clinical outcomes like death or hospitalization in this group of patients. Although some studies have shown a higher incidence of sudden death and serious arrhythmia in patients with small VSDs[12] this has not been borne out in other large population-based registries. Furthermore, there is no existing literature that clearly demonstrates that closing the VSD eliminates this risk of arrhythmia and/or sudden death. Larger, prospective studies are needed to ascertain the clinical impact of left heart volume loading on outcomes and the threshold for intervention in this group of patients.”
“Reports on the natural history of isolated small VSDs have been published as early as the 1970s with a spontaneous closure rate of 75% in a small cohort of 50 infants followed up for up to 10.5 years.[2] Two further cohort studies (n = 222 and n = 124) of patients with isolated small VSDs followed up for a mean duration of 12 months showed a spontaneous closure rate of 34% at 1 year of age.[3,4] This rate was higher (45%) in patients detected at birth.[3] “
“In the cohort of 124 infants, the incidence of spontaneous closure was found to increase to 67% at 5 years of age.[4] A retrospective review of 882 patients with isolated VSD of which 77% were asymptomatic, small defects showed that 40% of the small defects closed spontaneously during a mean follow-up of 9.5 years.[5]”
“Serial annual evaluation of 106 older children with isolated VSD from a mean age of 8.6 years to a mean age of 16.6 years showed spontaneous closure of the defect in 24 children and a significant decrease in mean defect diameter from 5.3 to 2.7 mm indicating that there remains a significant chance of spontaneous closure and decrease in defect size even into adolescence.[6]”
“A large registry cohort of 3495 children from Norway with an isolated VSD showed a low incidence of infective endocarditis of 0.9% (0.1 per 1000 person-years).[10]”
“In addition to reports of infective endocarditis in untreated VSDs, there are several case reports of infective endocarditis following both surgical and transcatheter closure of VSDs.[14,15,16,17] A study of 125 patients with isolated VSD who were followed up for a mean of 15 years showed no statistical difference in the incidence of bacterial endocarditis between the untreated patients (4.3%) and those that were surgically closed (2.7%) although the sample size of the study was small.[18] The Swedish registry data also showed an incidence of endocarditis of 1.2% in patients who had undergone surgery for VSD versus an overall incidence of 2% in the entire group.”
“Closing a VSD, therefore, does not seem to abolish the risk of endocarditis, which is anyway quite low in a population setting. Perhaps advice regarding dental hygiene would have a greater impact in reducing infective endocarditis than device closure.”
“With the unregulated and widespread use of transcatheter intervention to close small, restrictive mainly perimembranous VSDs we enter unchartered territory, which is unsubstantiated by clinical evidence. Published literature is filled with several reports of complications of device closure of VSDs, yet most papers conclude that the risks and complications are within acceptable limits. If a procedure is performed without clear indication, no risk however small is acceptable. “Primum nonnocere” or “ first, do no harm” has been famously attributed to being a part of the Hippocratic Oath but although it was written by Hippocrates (in a slightly different form) it forms part of a different work called “Of the Epidemic.” It is, however, a reminder that we need robust research to help us understand better the balance of risk and benefit for the treatments that we recommend to our patients.”
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5241834/
