Factors influencing late course of residual valvular and infundibular gradients following pulmonary valve balloon dilatation

Background: Though acute and follow-up benefits of pulmonary valve balloon dilatation (PVBD) for pulmonic valve stenosis are well known, the late cour se of residual gradients at individual valvular and infundibular levels is not well described. Furthermore, the factors influencing this late course h ave not been studied. Materials and 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) follow ing PVBD. The patients were divided into three groups based on the residual gradients at valvular and infundibular levels immediately following PVBD a s assessed by pull-back of an end-hole catheter across the right ventricula r 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 pre dominantly infundibular gradients of more than 30 mmHg with a valvular grad ient of less than 30 mmHg (n = 27, 28.1%), and Group C with a residual valv ular gradient of greater than 30 mmHg irrespective of the infundibular grad ient (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 tra ps-pulmonary gradient was 20 +/- 14 mmHg which was significantly lower than that immediately post-PVBD (43 +/- 32 mmHg), P < 0.001. The late fall (mea n 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 PVB D) 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 particu lar, each one of the patients in Group B showed decrease in traps-pulmonary gradients. On multivariate analysis, the extent of infundibular gradient e merged as the most important predictor of late fall (coefficient of determi nation 75%, P < 0.0001). Patients who underwent PVBD at less than 2 years o f age had a significantly greater late fall (41-1-33 mmHg) as compared to o lder patients (22 +/- 25 mmHg), P < 0.05. A sub-optimal long-term result (t ranspulmonary gradient > 25 mmHg, n = 24) was significantly related to olde r age (P < 0.001), dysplastic valve morphology (P = 0.002), greater baselin e traps-pulmonary gradients (P < 0.001) and higher post-PVBD gradients (P = 0.04). Conclusions: The long-term course of patients following PVBD depend s upon the site and magnitude of the residual gradients. Even high residual infundibular gradients show marked reduction at follow-up, especially in i nfancy. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.