Short term results of balloon pulmonary valvuloplasty in children : a single centre study over a period of 42 months

Objectives: To evaluate the efficacy and safety of balloon pulmonary valvuloplasty (BPV) in children. Design, setting and method: This is a retrospective review of 101 consecutive patients with pulmonary stenosis who underwent BPV at the Lady Ridgeway Hospital for Children over a period of 42 months. Four patients were excluded as they had complex cardiac problems. Data was obtained from Excel based cardiac catheterization reports in the Department of Paediatric Cardiology. Reduction of pressure gradient across pulmonary valve to less than 25 mmHg was defined as a successful procedure. Results: Ninety seven BPVs were performed in 94 patients. The mean age, bodyweight and height were 19 months, 9.5 kg and 80 cm respectively. Sex distribution was equal. The mean of the balloon to pulmonary annular ratio was 108% (range 50-150%). After the BPV, mean peak to peak pressure gradient across the pulmonary valve dropped from 70±29 mmHg to 24.7±16.8 mmHg. Overall success rate was 55.7%. Mortality was 3.1%. Major complications were haemopericardium (4.1%), bradycardia (2%) endocardial damage (1%) and pulmonary oedema (1%). The correlation between pulmonary annulus on echocardiography and angiography was significant (p<0.01). _________________________________________ 1 Department of Paediatric Cardiology, Lady Ridgeway Hospital for Children, Colombo, 2 Department of Cardiology, National Hospital, Colombo, 3 Department of Cardiology, Teaching Hospital, Colombo North, Ragama, 4 Department of Community Medicine, University of Colombo (Received on 3 April 2010. Accepted on 20 May 2010) Introduction Congenital pulmonary valve stenosis (PS) has been found in 8-10% of patients with congenital heart diseases 1 . Right ventricular dysfunction, fibrosis or infarction may be seen in patients with severe PS 1-3 . Pulmonary valvuloplasty is the first option in the management of congenital PS 4-8 . The short term results of pulmonary valvuloplasty in children with typical PS have been excellent 9-13 . Complications are lower in children and adults than in infants and neonates. Mortality and morbidity among neonates were 3% and 10% respectively 14 . Studies on balloon pulmonary valvuloplasty (BPV) have not been conducted previously in Sri Lanka.

Complications are lower in children and adults than in infants and neonates.Mortality and morbidity among neonates were 3% and 10% respectively 14 .
Studies on balloon pulmonary valvuloplasty (BPV) have not been conducted previously in Sri Lanka.

Method
This is a retrospective study of 101 consecutive patients with pulmonary stenosis who underwent BPV at the Lady Ridgeway Hospital for Children (LRHC) over a period of 42 months from 1 st January 2006 to 30 th June 2009.Four were excluded as they had complex cardiac problems with pulmonary stenosis.Well designed and maintained Excel based cardiac catheterization reports in this unit were reviewed and the data was collected into a data extraction Excel sheet.

Results
Immediate and short term outcomes of BPV were reviewed.There were 94 children aged 2 days to 12 years (mean 19 months) who underwent BPV.Categorization of cases is shown in Table 1.The pulmonary annular size on echocardiography and angiography were 12±3.8mm and 12.53±4mm respectively.The correlation between these two was significant at 0.01level as shown in Figure 1.

Failures
The procedure was unsuccessful in 36 patients, 24 of whom had residual pressure gradient between 26-50 mmHg (24.7%) and only five patients had gradient of >50mmHg.The procedure failed in 7 with critical pulmonary stenosis (unable to cross the pulmonary valve in 6, endocardial damage in one).However the numbers are inadequate for statistical analysis and the characteristics of the failures are shown in Table 3. Failure of crossing the pulmonary valve was seen in 2 neonates and 4 infants less than 6 months with critical pulmonary stenosis, two expired, one underwent repeat BPV and three were referred for surgery.
Severe residual stenosis (PG >50mmHg) was seen in infants with hypoplastic pulmonary annulus (2) and severely dysplastic pulmonary valves (3).They were referred for surgery.There were 3 deaths in this cohort.Complications of BPV are shown in Table 4.

Discussion
In a newly established and only paediatric cardiology unit in Sri Lanka, a significant number of patients with moderate to severe pulmonary stenosis underwent BPV over a short period in spite of having limited resources and a new staff with minimal prior experience.The transpulmonary gradient dropped from 70.50±29.25mmHg to 24.7±16.8mmHg after the BPV.It is comparable with the other studies 10,11 .
The overall success rate was 55.7%.In this study, procedure failure was mainly due to an inability to cross the severely stenotic valve.The same pattern was reported in other studies and this was overcome by the availability of new instruments.In addition, the experience of staff increased over time.However, the success rate is lower than in the centres with latest facilities which can achieve dilatation in 90-100% patients 1 .Early studies have shown the higher mortality and morbidity in neonates and infants 14 .The mortality rate in our series was 3.1% which is similar to some centres 14 .As seen in other studies, complications were common in neonates and infants 14 .
A limitation of this study is that data was obtained from the service records which were not specifically designed for this research.

Conclusions
• Overall success rate of BPV was 55.7%.
• Correlation between pulmonary annulus on echocardiography and angiography was significant (p<0.01).