Short- and Intermediate-Term Follow-up Results of Percutaneous Transluminal Balloon Valvuloplasty in Adolescents and Young Adu
- Volume 15 - Issue 11 - November, 2003
- Posted on: 8/1/08
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PVS, usually due to dome-shaped valve apparatus, resulting from commissural fusion, comprises approximately 10% of all congenital heart diseases1–3 including 10–15% dysplastic valves,4–6 which are due to markedly thickened immobile cusps with variably reduced mobility. In moderate-to-severe valvular pulmonary stenosis (PS), subvalvular hypertrophy can cause infundibular narrowing and obstructive hemodynamics, which regresses after correction of valvular stenosis.7–9 Similarly, cyanosis can occur with right-to-left atrial shunting through a patent foramen ovale due to severe PS and decreased right ventricular chamber compliance.
Kan et al.10 introduced PBV in 1982, and since then this has become the treatment of choice for both children and adults. The short and long-term results of PBV are excellent and comparable to surgery.6,11–14 However, data from our country is scarce, therefore, we conducted a prospective study to determine the feasibility as well as the non-invasive intermediate-term follow-up results of PBV of isolated congenital pulmonary valve stenosis.
Patients. Between June 1997 and December 2001, 25 patients, ages 14–20, diagnosed on two-dimensional Doppler echocardiograms as having moderate-to-severe PVS, at the National Institute of Cardiovascular Diseases (NICVD) Karachi, Pakistan, were enrolled. Only patients with a right ventricular systolic pressure > 50 mmHg were selected for balloon valvuloplasty.15,16 However, cyanosed patients with right-to-left atrial shunt through patent foramen ovale due to severe PS and right ventricular compliance failure were also included. All patients had clinical and echocardiographic evidence of moderate to severe PVS with transvalvular pressure gradient > 50 mmHg.
Patients with associated congenital malformations like large atrial septal defects, ventricular septal defects, tetralogy of fallot, patent ductus arteriosus and pulmonary incompetence, diffuse pulmonary artery branch stenosis, ebstein anomaly, severe infundibular stenosis, or significant medical complications such as infective endocarditis were excluded from the study.
All patients had an ECG, chest x-ray, and two-dimensional color Doppler echocardiography done before and after cardiac catheterization and cineangiography. A fixed-size Mansfield Catheter (Mansfield Scientific, Watertown, Massachusetts) was used for PBV, due to its cost-effectiveness; a major concern in developing countries. The technique was similar to that reported earlier.3,17,18
The acceptable endpoint was an appropriately-sized balloon inflation without difficulty and without a discernible waist. Significant acute reduction in the peak systolic pulmonary valve gradient to < 30 mmHg (i.e. mild residual stenosis) was considered as a successful outcome.19 The procedure was considered unsuccessful if the residual pulmonary valve gradient remained > 50 mmHg at follow-up.9 Figure 1 shows the right ventriculogram before dilation, Figure 2 shows a fully inflated blalloon wihtout discernible waist, and Figure 3 shows a post-procedure right ventricular cineangiogram showing successful PBV. Two-dimensional Doppler echocardiography was done in all patients on the next day of procedure and then on follow-up visits.
Follow-up. There is an acceptable correlation between the measured pulmonary valvular pressure gradients both from cardiac catheterization and Doppler echocardiogram during the follow-up period;6 therefore, repeated cardiac catheterization for follow-up was not done, and only a Doppler echocardiogram was performed initially on next day of procedure (PBV). This was then done after the first six months and later yearly (up to five years), in order to evaluate the residual transvalvular pressure gradient. Patients were also advised to continue beta-blockers during follow-up period for the regression of residual infundibular hypertrophy.
Statistical analysis. Continuous variables were presented as means ± standard deviation (SD). Two-tailed Students ‘t’ test for paired data was used for comparison of pressure gradients. A p-value of < 0.05 was considered statistically significant.
Twenty-five patients with isolated pulmonary valve stenosis under went percutaneous transluminal balloon valvuloplasty. There were 15 males (60%) and 10 females (40%); with the mean age of 15.7 ± 1.8 (range 14–20) years. Table 1 summarizes the clinical features of all patients. The most common clinical presentation in decreasing frequency was dyspnoea, cyanosis, chest pain and right heart failure. All patients had right ventricular hypertrophy, 12% had each right atrial hypertrophy and right axis deviation. Post-stenotic pulmonary artery dilatation (prominent pulmonary segment) was present in 84%, and 28% had decreased pulmonary vascular markings. On two-dimensional Doppler echocardiogram the mean pulmonary valve annulus, in short axis view, was 13.8 ± 3.1 mm, while on right ventricular (RV) cineangiogram it was 15.6 ± 2.6 mm.
Twenty patients (80%) had successful dilatation while the remaining 5 (20%) had unsuccessful dilatation. In successful PBV patients, the right ventricular mean systolic pressure (Figure 4) decreased from pre-dilatation pressure of 116.9 ± 32.4 mmHg to 60.5 ± 18.7 mmHg after PBV (p < 0.0001). The transpulmonic valve peak-to-peak pressure gradient fell significantly from 93.5 ± 32.8 to 33.5 ± 9.7 mmHg after PBV (p < 0.0001) and further decreased to 18.6 ± 3.4 (p < 0.0001) at one-year follow-up (Figure 5). The pulmonary artery systolic pressure increased from 19.7 ± 6.5 to 25.8 ± 7.3 (p < 0.0001) suggesting an increase in the right ventricular stroke volume (Table 2).
For 7 patients with dysplastic valves, a balloon of 1.4 times the size of the pulmonary vein (PV) annulus (balloon/annulus ratio = 1.4) was used, but by large the procedure remained unsuccessful as only 2 patients were successfully dilated and other 5 had unsuccessful PBV. In these 5 unsuccessful PBV patients (all of them had dysplastic valves) the decrease in right ventricular mean systolic pressure and transpulmonic valve peak-to-peak pressure gradient was from 139.8 ± 50.4 mmHg to 128.6 ± 52.2 mmHg and 110.8 ± 58.6 to 100.8 ± 55.1 mmHg respectively, after PBV.
Among 4 cyanotic patients 3 had successful PBV, following which the cyanosis was corrected, while the remaining patient with an unsuccessful procedure, who had a dysplastic pulmonary valve, was then sent for surgical correction. However, there was no significant difference in the percentage of gradient relief in the 2 groups (i.e. cyanotic and non-cyanotic patients) as it was 66% in cyanotic patients and 60.4% in non-cyanotic patients.
The mean follow-up period of 20 successful patients was 3.2 ± 1.2 years (range 1–5 years). Yearly follow-up with Doppler echocardiogram showed a further decrease in transvalvular pressure gradient (18.6 ± 3.4 mmHg after 1 year, 16.8 ± 2.9 mmHg after 2 years, 16.2 ± 3.8 mmHg after 3 years, 15.8 ± 3.2 mmHg after 4 years and 13.5 ± 2.1 mmHg after 5 years of procedure). This decrease in residual pressure gradient was due to the regression of infundibular hypertrophy after PBV. The unsuccessful procedures were referred for surgical correction.
Complications. No major complication like persistent arrhythmias and bradycardia was noted. Only 3 patients had developed mild pulmonary valve regurgitation on the Doppler echocardiography and 2 patients had premature ventricular contraction or short episodes of bradycardia during or immediately after balloon dilation, which resolved spontaneously. The patients were discharged on next morning after echocardiography.
PBV provides an effective relief of critical pulmonary valve stenosis in children, adolescents and adults.6,15,20–23 This is the first study on PBV in adolescents and young adults from Pakistan showing intermediate-term follow-up. We demonstrated significant reduction in pre-dilatation gradient in 80% of our patients. The presence of dysplastic valves affected the successful dilatation in our series of patients, as they are less liable to successful dilatation and frequently require surgical treatment.24 Another factor may be the balloon size that we used (balloon/annulus ratio = 1.2–1.4), it is possible that larger size balloon might have achieved more optimal results in patients with dysplastic valves.25,26
During the follow-up period we demonstrated further decrease in transpulmonic valve peak-to-peak pressure gradient, a finding similar to previously published reports on follow-up data.6,26,27 This reduction of residual pressure-gradient was mainly due to regression of reactive infundibular hypertrophy, as proven in earlier studies,6–9,13,14,16,27 requiring no more balloon dilatation.
Twelve percent of our patients with severe RV dysfunction and cyanosis, due to a R-L shunt at the atrial level, showed marked improvement of right ventricular function after successful PBV as both cyanosis and right heart failure resolved completely during follow-up period.
The reported experience showed that once successful dilatation has initially been achieved, then the chances of restenosis are very rare9,13 Thus, patients with successful PBV with good intermediate-term follow-up results are expected to remain asymptomatic for long-term as well without the need for further dilatation.
In summary, the study showed successful results of BPV in adolescents and young adults with good intermediate-term follow-up results. Therefore, a fixed-size Mansfield Catheter can still be used successfully, especially in developing countries where procedural cost are a major concern, as Invoue balloon catheters are costly. Also, the non-invasive studies with Doppler echocardiogram avoid the need of invasive studies like cardiac catheterization for follow-up.