Validation of risk factors in predicting recoarctation after initially successful balloon angioplasty for native aortic coarctation

Balloon Dilatation in the Management of Congenital Obstructive Lesions of the Heart: Review of Author's Experiences and Observations-Part I

Balloon dilatation techniques became available to treat congenital obstructive lesions of the heart in the early/mid-1980s. The purpose of this review is to present the author's experiences and observations on the techniques and outcomes of balloon dilatation of pulmonary stenosis (PS), aortic stenosis (AS) and aortic coarctation (AC), both native and postsurgical re-coarctations. Balloon dilatation resulted in a reduction of peak pressure gradient across the obstructive lesion at the time of the procedure as well as at short-term and long-term follow-ups. Complications such as recurrence of stenosis, valvar insufficiency (for PS and AS cases) and aneurysm formation (for AC cases) have been reported, but infrequently. It was recommended that strategies be developed to prevent the reported complications.

Statistical Treatment of Clinical Investigations in Pediatric Cardiology

This paper describes various statistical methods used by the author during multiple studies conducted by the author. Initially, the data were scrutinized to ensure normal distribution, and expressed as mean ± standard deviation (SD) or standard error of mean (SEM) for normally distributed variables. Medians and ranges were given for the data with skewed distribution. Two tailed, paired t tests or independent sample t tests (analysis of variance) were used for normally distributed data, while non-parametric chi-square or similar other tests were utilized for data with skewed distribution. Statistical significance was set at a p value of < 0.05. Bonferroni correction was applied when the study involves multiple comparisons. A number of other statistical methods used during these studies were also discussed. Finally, special methods used in evaluating aortic remodeling subsequent to balloon angioplasty of native aortic coarctation were reviewed.

Surgical outcomes in complex adult congenital heart disease: a brief review

Life expectancy of patients with congenital heart disease (CHD) continues to increase dramatically over the last few decades, primarily due to significant medical and surgical advancements in the field. Adult congenital heart disease (ACHD) patients are now living longer but continue to face morbidity and reduced long-term survival when compared to the general population. We briefly describe the growth of ACHD with a focus on surgical procedures and outcomes in the more complex lesions including Tetralogy of Fallot, Ebsteins Anomaly of the tricuspid valve, Coarctation of the Aorta, Transposition of the Great Arteries and single ventricle lesions. The advancing role of mechanical circulatory support and cardiac transplantation in ACHD patients is also highlighted. Cardiac surgery in these patients continues to improve with low surgical mortality rate and outstanding long-term outcomes and efficacy.

Use of covered stents in simultaneous management of coarctation of the aorta and patent ductus arteriosus

Objective:

To report clinical and procedural characteristics of twelve patients who received a covered stent for the treatment of aortic coarctation and concurrent patent ductus arteriosus (PDA).

Methods:

A single center database was retrospectively evaluated to obtain data of patients with combined aortic coarctation and PDA. We selected patients in whom a covered stent was used for the treatment of both pathologies. The stent length was chosen so as to cover the entire length of the lesion from healthy to healthy tissue and also cover the ampulla of PDA.

Results:

The median age of the patients was 15 (range, 6.5-35) years. The diameter of the coarctated segment increased from a median of 8.4 (range, 2.6-10.8) mm to 16 (range, 9-24) mm (p<0.005), whereas the pressure gradient decreased from a median of 43 (range, 10-71) mm Hg to 0 (range, 0-8) mm Hg (p<0.005). Fourteen covered stents were used for 12 patients. Following deployment, seven stents were flared with larger and low-pressure balloons because of the gap between the distal end of the stent and the poststenotic dilated segment of the aorta, which caused residual PDA shunts and/or instability of the stent. After the procedure, no residual PDA shunt was present in any patient.

Conclusion:

To the best of our knowledge, this study includes the largest series of patients reported in literature in whom covered CP stents were used for simultaneous percutaneous treatment of coarctation and PDA. The procedure was successful and stable results were obtained during follow-up in all cases.

The Journey of an Indian Pediatric Cardiologist : Dr. K. C. Chaudhuri Lifetime Achievement Award/Oration at AIIMS, New Delhi, September 2017

The life journey of an Indian pediatric cardiologist, who bestowed considerable attention to the development of new knowledge and train/teach physicians around the world while providing care of patients with heart disease over a 45-y period, is reviewed. This appraisal focuses particular attention on the scientific contributions to the literature. These include spontaneous closure of physiologically advantageous ventricular septal defects, various issues related to a congenital heart defect namely, tricuspid atresia and transcatheter and, interventional pediatric cardiac procedures.

Does the z-score value of the abdominal aorta predict recoarctation in an infant?

OBJECTIVE

We evaluated left ventricular dimensions and aortic arch z-scores in infants who underwent balloon angioplasty (BAP) or surgery for coarctation of aorta (CoA). We searched for risk factors predicting recoarctation.

PATIENTS

Between 2007-2011, 27 male and 17 female infants (mean age 2.93 ± 4.78 months, range 2 days-24 months) with CoA were evaluated. Left ventricular dimensions, systolic functions, mitral and aortic annuli, transverse aortic arch, isthmus, coarctation site, and diaphragmatic aorta measurements were done and z-scores were determined before intervention.

RESULTS

Six patients underwent primary operation, 38 patients had BAP (86.4%). Associated cardiac pathologies in operated patients were double outlet right ventricle (n = 2), atrioventricular septal defect (n = 1), Ebstein's anomaly (n = 1), arch hypoplasia (n = 2). Twelve patients (27.2%) had simple coarctation. Ventricular septal defect was the most frequent associated cardiac pathology (n = 20, 45.4%). The patients were followed for 10.22 ± 8.21 months. Among 33 primary successful BAP's, 14 had recoarctation (42%). Eleven patients were primarily operated (including 5 with unsuccessful BAP), two had recoarctation (18%). Abdominal and transverse aorta values and z-scores were significantly lower in the recoarctation group (7.15 ± 2.12 mm and 6.07 ± 1.86 mm respectively in the "no-recoarctation group"; vs. 5.53 ± 0.75 mm and 4.94 ± 1.53 mm in the "recoarctation group" P <.05). Abdominal aorta z-score of 0.42 was 88.9% sensitive and 53.8% specific to predict recoarctation (area under ROC curve: 0.618-0.902, P <.05).

CONCLUSION

Although BAP for native coarctation is still a controversial treatment option due to frequent restenosis rates, abdominal aorta z-score of 0.42 could correctly eliminate recoarctation in 89% of these cases. This cutoff value might help us choose patients for primary BAP and decrease the recoarctation rate after BAP.

Balloon angioplasty for native coarctation of the aorta in neonates and infants with congestive heart failure

BACKGROUND

Balloon angioplasty (BA) is an alternative to surgical repair for coarctation of the aorta (CoA) in children. However, its role in the treatment of native CoA in neonates and infants remains controversial. The purpose of this study was to report the midterm outcomes of BA for native CoA in neonates and infants with congestive heart failure (CHF).

METHODS

Between July 2000 and March 2007, 18 neonates and infants with native CoA and CHF who underwent BA were enrolled. Patients without recoarctation were designated as group A, while those with recoarctation or CHF were designated as group B. The clinical presentations, laboratory data, and outcomes were compared between groups.

RESULTS

There were 10 patients in group A and eight in group B. The mean age was 2.8 +/- 3.1 months (range, 0.7-11 months). Mean body weight was 4.0 +/- 1.9 kg (range, 2.1-8.0kg). CHF improved markedly in all patients immediately after BA, with a reduction in systolic pressure gradient from 36.4 +/- 12.0 to 5.6 +/- 6.0 mmHg (p < 0.001). The recoarctation rate was 44% (8/18). The risk factors for restenosis were post-BA systolic pressure gradient >10 mmHg (p = 0.007) and CoA diameter <3 mm (p = 0.013).

CONCLUSIONS

The outcomes of BA for native CoA in neonates and infants with CHF remain poor. The incidence of recoarctation is high in neonates and patients whose post-BA systolic pressure gradient is >10 mmHg or whose CoA diameter is <3 mm.

Safety and efficacy of low-profile balloons in native coarctation and recoarctation balloon angioplasty for infants

Background Traditionally, high-profile/high-pressure balloons have been used for angioplasties, whereas low-profile/low-pressure balloons have been used for valvuloplasties. High-profile balloons require larger introducing sheaths, which can be a limiting factor for percutaneous catheter interventions in infants. This report aims to report the author's experience with the efficacy of low-profile balloons using smaller introducing sheaths for coarctation balloon angioplasty in infants. Methods From April 2004 to April 2008, 15 infants, representing both native coarctation and recoarctation indications, underwent coarctation balloon angioplasty and were retrospectively reviewed. The arterial access was achieved using 4-Fr (Cook) introducing sheaths and Tyshak (NuMED, Hallenweg-Netherlands) balloons 5 to 8 mm in diameter for coarctation angioplasty in the study group. Results In this study, 15 infants (7 with native coarctation and 8 with postoperative recoarctation) underwent balloon angioplasty. These infants ranged in age from 2 to 9 months (median, 4 months) and in weight from 3.5 to 10.8 kg (median, 5.7 kg). The peak-to-peak coarctation gradient was reduced from 46.2 +/- 28 mmHg before angioplasty to 10 +/- 8 mmHg afterward (p = 0.001). The angiographic diameter of the coarctation segment was increased from 2.4 +/- 1.0 mm before angioplasty to 5 +/- 0.8 mm afterward (p = 0.001). There were no immediate major or minor complications. During a follow-up period up to 48 months, only one patient from the native coarctation group experienced recoarctation and underwent successful reballooning, and none of the patients experienced aneurysms. Conclusion This study shows that the use of low-profile/low-pressure balloons is an effective treatment for infants. Furthermore, low-profile balloons required smaller introducing sheaths, which provides a clear advantage of minimizing vascular complications with coarctation ballooning in younger infants.

Intraluminal aortoplasty vs. surgical aortic resection in congenital aortic coarctation. A clinical random study in pediatric patients

BACKGROUND

Our objective was to compare results of two therapeutic modalities to treat congenital aortic coarctation: intraluminal aortoplasty without endoluminal stent installation (patients in group A) vs. surgical aortic resection (patients in group B). Trans-coarctation gradient pressure was evaluated prior to and immediately after treatment. Re-coarctation, aneurysm formation, in-hospital morbidity and mortality, and complications related to treatment were also evaluated.

METHODS

A clinical, randomized, multicenter study was performed in pediatric patients with congenital aortic coarctation. Immediate and mid- to late therapeutic results were evaluated. With regard to statistics, we evaluated event variations by Kaplan-Meier model, nonparametric Wilcoxon test, Mann-Whitney U test, two-tailed Student t and chi-square tests, and Fisher analysis. Significance was considered relevant when p<0.05.

RESULTS

There were no differences in demographic variables, procedure failure, complications, mortality, or aortic aneurysm between groups A and B, respectively. Intraluminal angioplasty and surgical aortic resection were similarly effective in reducing trans-coarctation pressure gradient, as well as arterial systemic pressure. However, differences were found between groups A and B at follow-up. Group A showed higher re-coarctation (50 vs. 21%). Absence of peripheral arterial pulses in limbs was higher in group A (50 vs. 21%), as well as persistence of arterial hypertension (49 vs. 19%); these differences were significant (p<0.05). On the other hand, complications observed after surgical aortic resection were more serious than post-angioplasty complications, but these differences were not statistically significant.

CONCLUSIONS

Although re-coarctation and persistency of arterial hypertension were less frequent after surgical aortic resection, complications observed with this procedure are more serious than complications related to angioplasty, although these differences are not statistically significant.

Outcomes of transcatheter balloon angioplasty of obstruction in the neo-aortic arch after the Norwood operation

Obstruction of the reconstructed aortic arch, or the neoaortic arch, is now known to be an important factor increasing mortality after the Norwood operation for hypoplastic left heart syndrome. Transcatheter balloon angioplasty has been shown to provide effective relief of both native aortic coarctation and obstructions of the aortic arch occurring subsequent to therapeutic intervention. We sought to determine the outcomes of balloon angioplasty used as an initial treatment for obstruction of the neoaortic arch occurring after the Norwood operation. We gathered the characteristics of 58 patients with such obstruction from 8 institutions, noting procedural factors and outcomes of initial balloon dilation. Obstruction occurred at a median interval of 4 months, with a range from 1.5 months to 6.3 years, after a Norwood operation. Ventricular dysfunction was present before dilation in 13 patients. Mean peak to peak systolic pressure gradients were acutely reduced from 31+/-20 mm Hg to 6+/-9 mmHg (p<0.001), with outcome subjectively judged to be successful in 89%. Three patients with pre-existing ventricular dysfunction died within 48 hours of dilation. There were 10 additional deaths during the period of follow-up, with Kaplan Meier estimates of survival after intervention of 87% at 1 month, 77% at 12 months, and 72% after 15 months. In addition, 9 patients required re-intervention during the period of follow-up, with Kaplan Meier estimates of freedom from re-intervention after dilation of 87% at 6 months, 78% at 12 months and 74% after 18 months. Although transcatheter dilation of neoaortic arch obstructions after Norwood operation is successful, there is a high risk of re-intervention and ongoing mortality in this subgroup of patients. Close follow-up is recommended.

Restenosis after balloon angioplasty of coarctation: relationship with ductus arteriosus

BACKGROUND

Recently, balloon angioplasty (BA) has been used for the treatment of coarctation of the aorta (CoA) and the effectiveness of this treatment has been reported. However, the restenosis rate following BA in native CoA in the infant is high and the cause may be related to tissue properties at the origin of the ductus arteriosus (DA). However, the mechanisms responsible for restenosis remain uncertain.

METHODS/RESULTS

The present study was designed to examine transformation of the smooth muscle cell (SMC) phenotypes using immunohistologic studies and to investigate the cause of restenosis of CoA following BA. A CoA model was surgically created in 15 newborn pigs (10-14-days-old; 2.4-4.1 kg). Balloon angioplasty was performed 1 month after the initial operation. One or 3 months after BA, animals were killed and immunohistologic studies on smooth muscle cell (SMC) antibodies against SM1, SM2 and SMemb of the myosin heavy chain (MHC) isoform were performed in the aorta at the CoA and DA. In the neointima, only SMemb was positive. In the SMC layer of the DA, only SM2 was positive. One month after BA, the external layer of the tunica media was strongly positive for SM2 only in the area around the origin of the DA.

CONCLUSIONS

The first cause of restenosis is obstructive neointimal formation caused by the proliferation of undifferentiated SMC into the subendothelial tissue. This proliferation seems to be triggered by BA. The distribution of SM2 1 month after balloon angioplasty showed a similar pattern of proliferation of SMC in the external layer around the DA. This may represent a second mechanism of restenosis.

Long-term follow-up results after balloon dilatation of pulmonic stenosis, aortic stenosis, and coarctation of the aorta: a review

Although immediate and intermediate-term results after balloon dilatation of congenital stenotic lesions of the heart in children are well studied, long-term results have not been documented. Therefore, we reviewed our experience along with the limited published data to address this issue. Late follow-up after balloon pulmonary and aortic valvuloplasty shows low-residual gradients, reintervention-free rates in the mid-80s for pulmonic and in the mid-50s for aortic stenosis, and an increase in degree and prevalence of similunar valve insufficiency. Balloon angioplasty of aortic coarctation results in low-residual gradients, residual hypertension in a minority of patients, low prevalence of aneurysms, and high rates of recurrence in the neonate and young infant. Overall, balloon dilatation is a useful technique in relieving congenital obstructive lesions of the heart in the pediatric patient, but continued study of (1) late pulmonary and aortic insufficiency after valvuloplasty, (2) recurrence and aneurysms after balloon angioplasty of coarctations and, (3) femoral artery compromise in lesions requiring transfemoral artery approach is warranted.

Relation of biophysical response of coarcted aortic segment to balloon dilatation with development of recoarctation following balloon angioplasty of native coarctation

OBJECTIVE

To evaluate the role of biophysical response of the coarcted segment to balloon dilatation in the causation of aortic recoarctation.

SETTING

Tertiary care centre/university hospital.

DESIGN

Retrospective case series.

METHODS

Records of 67 consecutive infants and children undergoing balloon angioplasty of native aortic coarctations were examined for an 8.7 year period ending September 1993. At 12 months (median) follow up catheterisation, 15 (25%) of 59 children developed recoarctation, defined as a gradient > 20 mm Hg. Stretch (balloon circumference--preballoon coarcted segment circumference/preballoon coarcted segment circumference), gain (postballoon coarcted segment circumference--preballoon coarcted segment circumference), and recoil (balloon circumference--postballoon coarcted segment circumference) were calculated from measurements obtained from cineangiograms performed before and immediately after balloon dilatation.

RESULTS

The stretch in 44 children without recoarctation (2.18 (1.23)) was similar (p > 0.1) to that in 15 children with recoarctation (1.90 (0.65)), implying that similar balloon dilating stretch was applied in both groups. Greater gain (p < 0.05) was observed in the group without recoarctation (8.8 (8.0) mm) than in the recoarctation group (5.7 (2.7) mm) but this was not substantiated in the infant population. However, the recoil was greater (p < 0.001) in the group without recoarctation (5.1 (4.3) mm) than in the recoarctation group (2.1 (1.1) mm); this was also true in the infant group.

CONCLUSIONS

Greater recoil in the patients without recoarctation implies preservation of intact elastic tissue in the coarcted segment. In the recoarctation group, with less recoil, the elastic properties may not have been preserved, thereby causing recoarctation. There might be a more severe degree of cystic medial necrosis in the recoarctation group than in the no recoarctation group. This needs confirmation in future studies.

Balloon angioplasty for an unusual aortic coarctation

Percutaneous balloon angioplasty is an alternative therapy for the treatment of the typical type of coarctation. Its associated morbidity and mortality compares favorably when compared to the standard treatment surgery. While atypical coarctations are rare, the described cases have been treated surgically. We present a case of unusually located aortic coarctation successfully treated with percutaneous balloon angioplasty.

Balloon angioplasty for aortic coarctation--report of a questionnaire survey by the Japanese Pediatric Interventional Cardiology Committee

The aim of this study was to analyze the results of a questionnaire survey regarding acute and late effects of balloon angioplasty for aortic coarctation in Japan. Considerable controversy still exists regarding the effectiveness and safety of balloon angioplasty in native coarctation. Moreover, little information about this mode of treatment is available from Japan. A questionnaire was sent to 55 Japanese institutions with pediatric cardiology units. A total of 208 patients from 35 institutions were reported and analyzed for indications for balloon angioplasty, acute and late results, and complications. Balloon angioplasty was performed in 56 patients with native coarctation (group I) and in 152 patients with postoperative recoarctation (group II). In group I, the pressure gradient across the coarcted site decreased significantly from 34 +/- 19 to 16 +/- 21 mmHg (p < 0.001), and the diameter of the coarcted site increased significantly from 3.7 +/- 1.7 to 6.0 +/- 2.5 mm (p < 0.001). In group II the pressure gradient significantly decreased from 41 +/- 20 to 15 +/- 15 mmHg (p < 0.001) and the diameter of the coarcted site significantly increased from 4.2 +/- 2.2 to 6.8 +/- 3.1 mm (p < 0.001). The restenosis rate was significantly higher in group I (19/41, 46%) than in group II (25/139, 18%) (p = 0.0006). Redilation was successfully performed in 27 of 29 of the patients with restenosis. Major complications included femoral pulse loss, transient bradycardia, and arrhythmia. No patient died of a cardiac event related to the procedure. The significant risk factors for late restenosis included type of coarctation, age under 4 months, balloon size used, pressure gradient and coarctation diameter before the procedure. Balloon angioplasty is a suitable treatment for aortic coarctation in both native coarctation and postoperative recoarctation. Restenosis was significant after initial balloon angioplasty in native coarctation but redilation was effective in most cases. The most significant risk group for restenosis is young children with native coarctation.

Dilation mechanism, causes of restenosis and stenting in balloon coarctation angioplasty

This review focuses on the individual dilation mechanism, the possible cause of restenosis after balloon angioplasty and the clinical application of a stent in coarctation of the aorta. Balloon angioplasty is still not the first choice of therapy in neonates with native coarctation because of the potential risk of aortic disruption, the high incidence of restenosis and the satisfactory results of surgical coarctectomy. Intravascular ultrasound imaging provides the individual mechanism of aortic dilation by balloon, and this will be a new modality for assessing the relationship between restenosis and aortic luminal morphology after balloon dilation. Although the cause of restenosis after balloon angioplasty remains uncertain, it may be due to a combination of elastic recoil by ductal tissue constriction, intimal hyperplasia and arterial remodelling. A stent could be an effective alternative to conventional balloon angioplasty in native coarctation of the aorta, preventing ductal tissue constriction. However, the problematic relationship between patient growth and relative stenosis of the stent should be clarified before clinical application of a stent for this disease.

Acute results of balloon angioplasty of native coarctation versus recurrent aortic obstruction are equivalent. Valvuloplasty and Angioplasty of Congenital Anomalies (VACA) Registry Investigators

OBJECTIVES

This study sought to compare the immediate results and risk factors for suboptimal outcomes of percutaneous balloon angioplasty for native versus recurrent aortic obstruction.

BACKGROUND

Some cardiology centers have been reluctant to adopt balloon angioplasty for treatment of native aortic coarctation, while advocating balloon angioplasty over an operation for treatment of postsurgical or recurrent aortic obstruction.

METHODS

Acute results were analyzed from 970 procedures (422 native and 548 recurrent lesions) performed between 1982 and 1995 in 907 patients from 25 centers. An acute suboptimal outcome was defined as one or more of the following: residual systolic pressure gradient > or = 20 mm Hg, residual proximal to distal systolic pressure ration > or = 1.33 or a major complication (death, aortic transmural tear, stroke).

RESULTS

Bal loon angioplasty significantly (p = 0.0001) increased lesion diameter fo r both native (mean [+/= SD] 128 +/= 94%) and recurrent aortic obstruction (97 +/= 87%), with a significantly greater increase in the native group (p = 0.0001). A reduction in systolic pressure gradients was significant in both groups (p = 0.0001), but slightly higher (p = 0.01) for native (-74 +/- 24%) versus recurrent obstruction (-70 +/- 31%). Death associated with angioplasty was reported in 0.7% of patients with native and in 0.7% of patients with recurrent lesions (p = 1.00). An acute suboptimal outcome was noted with angioplasty in 19% of native and in 25% of recurrent lesions (p = 0.04). Significant independent risk factors included higher preangioplasty systolic gradient (odds ratio [OR] 1.39/10-mm Hg increment; 95% confidence interval [CI] 1.28 to 1.50, p = 0.0001), earlier study date (OR 0.92/1-year increment, 95% CI 1.02 to 1.26, p = 0.02) and recurrent obstruction (OR 1.39 vs. native lesions, 95% CI 1.00 to 1.94, p = 0.05).

CONCLUSIONS

Acute results and complications of balloon angioplasty of native coarctation appear to be equivalent or slightly superior to those of recurrent aortic obstructions.

Feasibility and effectiveness of repeated balloon dilatation of restenosed congenital obstructions after previous balloon valvuloplasty/angioplasty

Balloon dilatation of congenital stenotic lesions of the heart and great vessels has been used for more than a decade. Varying incidence of residual obstruction or recurrence, hereafter referred to as restenosis, has been observed at follow-up. The purpose of this study was to evaluate the feasibility and effectiveness of repeated balloon dilatation of restenosed lesions after previous balloon dilatation for pulmonic (PS) and aortic (AS) stenosis and native aortic coarctation (AC). Neonates, infants, and children (n = 178) underwent balloon valvoplasty/angioplasty with reduction (p < 0.001) or peak-to-peak systolic pressure gradients from 91 +/- 41 (mean +/- SD) mm Hg to 25 +/- 19 mm Hg, from 70 +/- 20 mm Hg to 26 +/- 12 mm Hg, and from 48 +/- 17 mm Hg, to 11 +/- 9 mm Hg in patients with PS, AS, and AC, respectively. Repeated catheterization or echo-Doppler studies or both were performed from 3 months to 5 years after initial balloon dilatation. Residual gradients at follow-up were 26 +/- 26 mm Hg, 34 +/- 20 mm Hg, and 16 +/- 15 mm Hg, respectively, for PS, AS, and AC and remained significantly lower (p < 0.01) compared with gradients before the balloon dilatation. However, when results of individual patients were scrutinized, 9 (11%) of 80 patients with PS, 6 (23%) of 26 patients with AS, and 16 (27%) of 60 patients with AC had restenosis, on the basis of standard criteria. Repeated balloon dilatation was performed with reduction (p < 0.05 to < 0.001) of peak-to-peak gradients from 89 +/- 40 mm Hg to 38 +/- 20 mm Hg in 9 patients with PS, from 77 mm Hg to 13 mm Hg and 66 mm Hg to 6 mm Hg, respectively, in 2 patients with AS, and from 38 +/- 11 mm Hg to 10 +/- 6 mm Hg in 12 patients with AC. Echo-Doppler studies, 2 to 6.5 years after repeated balloon dilatation, indicated excellent results, with residual peak instantaneous Doppler gradients of 24 +/- 13 mm Hg in PS, 43 +/- 20 mm Hg in AS, and 11 +/- 6 mm Hg in AC groups, respectively. This improvement is irrespective of the cause of restenosis after initial balloon valvuloplasty/angioplasty. From this experience, we conclude that repeated balloon dilatation is feasible and effective in relieving restenosis after initial balloon valvuloplasty/angioplasty.