title: Factors influencing late course of residual valvular and infundibular gradients following pulmonary valve balloon dilatation.
abstract: BACKGROUND
  Though acute and follow-up benefits of pulmonary valve balloon dilatation (PVBD) for pulmonic valve stenosis are well known, the late course of residual gradients at individual valvular and infundibular levels is not well described. Furthermore, the factors influencing this late course have not been studied.
  
  
  METHODS
  We assessed the transpulmonary gradients by echo-Doppler in 96 patients (61 male, mean age 10.7 years) at a mean follow-up interval of 58.8+/-32.1 months (minimum 2 years) following PVBD. The patients were divided into three groups based on the residual gradients at valvular and infundibular levels immediately following PVBD as assessed by pull-back of an end-hole catheter across the right ventricular outflow tract: Group A with minor pressure gradients at both valvular and infundibular levels of less than 30 mmHg (n=60, 62.5%), Group B with predominantly infundibular gradients of more than 30 mmHg with a valvular gradient of less than 30 mmHg (n=27, 28.1%), and Group C with a residual valvular gradient of greater than 30 mmHg irrespective of the infundibular gradient (n=9, 9.4%). Demographic characteristics, hemodynamic parameters and procedural variables were correlated with the change in gradient at follow-up (late fall) and with long-term results.
  
  
  RESULTS
  The mean follow-up trans-pulmonary gradient was 20+/-14 mmHg which was significantly lower than that immediately post-PVBD (43+/-32 mmHg), P<0.001. The late fall (mean 24+/-29, range -55 to 110 mmHg) varied widely depending upon the acute result group: patients in Groups A and B showed significant late fall of 9+/-12 mmHg (P<0.05 for follow-up gradient compared to that following PVBD) and 58+/-31 mmHg (P<0.0001), respectively, while patients in Group C showed an insignificant late fall of 14+/-37 mmHg (P=0.21). In particular, each one of the patients in Group B showed decrease in trans-pulmonary gradients. On multivariate analysis, the extent of infundibular gradient emerged as the most important predictor of late fall (coefficient of determination 75%, P<0.0001). Patients who underwent PVBD at less than 2 years of age had a significantly greater late fall (41+/-33 mmHg) as compared to older patients (22+/-25 mmHg), P<0.05. A sub-optimal long-term result (transpulmonary gradient >25 mmHg, n=24) was significantly related to older age (P<0.001), dysplastic valve morphology (P=0.002), greater baseline trans-pulmonary gradients (P<0.001) and higher post-PVBD gradients (P=0.04).
  
  
  CONCLUSIONS
  The long-term course of patients following PVBD depends upon the site and magnitude of the residual gradients. Even high residual infundibular gradients show marked reduction at follow-up, especially in infancy.
authors.affiliation: Department of Cardiology, Cardiothoracic Center, All India Institute of Medical Sciences, New Delhi 110029, India.
authors.forename: D
authors.initials: D
authors.lastname: Gupta
authors.forename: A
authors.initials: A
authors.lastname: Saxena
authors.forename: S S
authors.initials: SS
authors.lastname: Kothari
authors.forename: R
authors.initials: R
authors.lastname: Juneja
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002404:Catheterization; D002648:Child; D002675:Child, Preschool; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D007223:Infant; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011662:Pulmonary Subvalvular Stenosis; D011666:Pulmonary Valve Stenosis / Q000000981:diagnostic imaging / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome