Early complications of interventional balloon catheterisation in infants and children

Medium-Term Outcomes in Pediatric Patients Undergoing Cardiac Catheterization Early After Congenital Cardiac Surgery

Safety and acute outcomes for patients who need catheterization shortly after congenital cardiac surgery has been established; literature on mid-term outcomes is lacking. We sought to evaluate the mid-term outcomes of patients who undergo early postoperative cardiac catheterization. This is a retrospective cohort study of patients who underwent cardiac catheterization within 6 weeks of congenital cardiac surgery with longitudinal follow-up and assessment of mid-term outcomes. Multivariable analysis was utilized to relate variables of interest to outcomes. 99 patients underwent cardiac catheterizations within 6 weeks of cardiac surgery between January 2008 and September 2016. Forty-six (45.5%) interventional procedures were performed at a median age of 41 days (IQR 21-192) and a median weight of 3.9 kg (3.3-6.6). During a median follow-up duration of 4.24 years (1.6-5.6) in study survivors, 61% of patients remained free from the primary endpoint (death and/or transplant). Sixty-nine patients (69.7%) underwent an unplanned surgical or catheter procedure. Renal failure at catheterization (OR 280.5, p 0.0199), inotropic medication at catheterization (OR 14.8, p 0.002), and younger age were all significantly associated with meeting the primary endpoint. Patients requiring surgical intervention as an initial additional intervention underwent more unplanned re-interventions, while patients who survived to hospital discharge demonstrated favorable mortality, though with frequent need for re-intervention. In patients requiring early postoperative cardiac catheterization, renal failure, younger age, and need for inotropic support at catheterization are significantly associated with meeting the primary endpoint.

Complications during catheter-mediated patent ductus arteriosus closure and pulmonary balloon valvuloplasty

OBJECTIVES

To evaluate and illustrate complications of cardiac catheterisation and the associated risk factors of the most common cardiac intervention procedures.

MATERIALS AND METHODS

Retrospective study of clinical records of client-owned dogs presented to a cardiology referral centre between January 2006 and December 2017.

RESULTS

Five hundred and twenty-four dogs were included, 62 of which had complications. Complications were divided into technical complications and those due to unexpected additional anatomical abnormalities. Seven procedures (1.33%) were interrupted; five dogs (0.95%) subsequently underwent surgery, and four dogs died during the interventional procedure, indicating a mortality rate of 0.76% CLINICAL SIGNIFICANCE: There is a low risk of complications following closure of patent ductus arteriosus or pulmonary balloon valvuloplasty when carried out by a trained team using standardised procedures in a referral centre.

Complications of Cardiac Catheterization in Structural Heart Disease

Background and Objectives

Cardiac catheterization is used to diagnose structural heart disease (SHD) and perform transcatheter treatment. This study aimed to evaluate complications of cardiac catheterization and the associated risk factors in a tertiary center over 10 years.

Subjects and Methods

Total 2071 cardiac catheterizations performed at the Seoul National University Children's Hospital from January 2004 to December 2013 were included in this retrospective study.

Results

The overall complication, severe complication, and mortality rates were 16.2%, 1.15%, and 0.19%, respectively. The factors that significantly increased the risk of overall and severe complications were anticoagulant use before procedure (odds ratio [OR] 1.83, p=0.012 and OR 6.45, p<0.001, respectively), prothrombin time (OR 2.30, p<0.001 and OR 5.99, p<0.001, respectively), general anesthesia use during procedure (OR 1.84, p=0.014 and OR 5.31, p=0.015, respectively), and total procedure time (OR 1.01, p<0.001 and OR 1.02, p<0.001, respectively). Low body weight (OR 0.99, p=0.003), severe SHD (OR 1.37, p=0.012), repetitive procedures (OR 1.7, p=0.009), and total fluoroscopy time (OR 1.01, p=0.005) significantly increased the overall complication risk. High activated partial thromboplastin time (OR 1.04, p=0.001), intensive care unit admission state (OR 14.03, p<0.001), and concomitant electrophysiological study during procedure (OR 3.41, p=0.016) significantly increased severe complication risk.

Conclusion

Currently, the use of cardiac catheterization in SHD is increasing and becoming more complex; this could cause complications despite the preventive efforts. Careful patient selection for therapeutic catheterization and improved technique and management during the peri-procedural period are required to reduce complications.

What is the clinical utility of routine cardiac catheterization before a Fontan operation?

Patients with single-ventricle circulation presenting for Fontan completion routinely undergo cardiac catheterization despite ongoing debate concerning its additive value. Increasing interest in noninvasive preoperative evaluation alone led the authors to analyze the utility of routine pre-Fontan catheterization and to determine whether a subset of patients could avoid this invasive procedure. Patients younger than 5 years referred for pre-Fontan evaluation were retrospectively reviewed. Medical records and catheter angiograms were examined, and catheterizations were categorized as "additive" based on predetermined criteria. Associations between precatheterization variables, catheterization findings, and short-term postoperative outcomes were evaluated. Cardiac catheterization was clinically nonadditive for 89 of 175 patients undergoing pre-Fontan evaluation (51%). There were no robust precatheterization predictors of a nonadditive catheterization. Echocardiography did not fully demonstrate the relevant anatomy of 115 patients (66%), most frequently due to inadequate visualization of the pulmonary arteries, and 22 patients had additive catheterizations due to new diagnostic findings alone. Interventions at catheterization were frequent and deemed "important" for 64 patients (37%). Catheterization hemodynamic data were not associated with early postoperative outcomes. Minor catheterization complications occurred for 51 patients (29%) and major complications for 4 patients (2%). Although at least 50% of the patients presenting for Fontan completion may be able to avoid routine catheterization safely, an echocardiography-based imaging strategy alone is insufficient to allow proper identification of those who could be evaluated noninvasively. A more comprehensive imaging strategy not based solely on echocardiography should be considered.

Complications of pediatric cardiac catheterization: a review in the current era

OBJECTIVE

To determine types of complications and risks associated with pediatric cardiac catheterization in the current era.

BACKGROUND

Pediatric cardiac catheterization is an important diagnostic and therapeutic tool. Although in the last decade, there have been significant improvements in technology and equipment, the risk for complications remains, adversely effecting outcomes.

DESIGN

The clinical records of 11,073 children undergoing cardiac catheterizations between January 1994 and March 2006 were reviewed to identify procedures associated with complications within the first 24 h after catheterization. All children's electronic and paper chart records were reviewed to obtain demographic, procedural, and treatment data.

RESULTS

A total of 858 (7.3%) complications (classified as major or minor) occurred in 816 studies (510 males, 63%), in children ranging in age from 8 h to 20 years (median 4.13 years). There were 195 major (22%) and 663 (78%) minor complications. Vascular complications represented the majority (n = 278; 32.4%) and were major in 53 instances (P < 0.0001). Twenty-five children died within 24 h (0.23% of total case numbers). Independent risk factors for a complication included young patient age (<6 months), male gender, inpatient status, and year of catheterization.

CONCLUSIONS

Complications continue to be associated with pediatric cardiac catheterization, although overall incidence appears to be decreasing. Patient age, gender, and inpatient status continue to be risk factors for morbidity and mortality. Efforts at improving equipment for flexibility and size, and developing strategies for the use of alternative methods for catheter access should be encouraged.

Cardiac Magnetic Resonance Versus Routine Cardiac Catheterization Before Bidirectional Glenn Anastomosis in Infants With Functional Single Ventricle

Background— Routine preoperative catheterization is standard practice in patients with single-ventricle physiology before bidirectional Glenn anastomosis. Because catheterization is invasive and exposes patients to ionizing radiation, cardiac magnetic resonance (CMR) may be a safe and effective alternative.

Methods and Results— We conducted a prospective, randomized, single-center clinical trial comparing catheterization with CMR in patients considered for bidirectional Glenn operation from February 2003 to June 2006. End points were frequency of adverse events of the preoperative evaluation and a composite score of clinically successful surgery. Of 92 eligible patients, 82 were enrolled on the basis of screening echocardiogram, fulfillment of inclusion criteria, and informed consent. Patients were randomized to catheterization (n=41) or CMR (n=41). There were no baseline differences between groups. Four treatment crossovers occurred, 3 to catheterization and 1 to CMR. Catheter interventions were performed in 17 patients (41%). Catheterization resulted in more minor adverse events (78% versus 5%; P <0.001), longer preoperative hospital stays (median, 2 versus 1 day; P <0.001), and higher hospital charges ($34 477 versus $14 921; P <0.001). There was 1 major adverse event in the CMR group ( P =1.0). The operative course and frequency of postoperative complications were similar between the 2 groups. The proportion of patients who had a successful bidirectional Glenn operation was similar (71% versus 83%; P =0.3). At the 3-month follow-up, there were no differences in clinical status, oxygen saturation, or frequency of reinterventions.

Conclusions— CMR is a safe, effective, and less costly alternative to routine catheterization in the evaluation of selected patients before bidirectional Glenn operation. Further studies are necessary to determine whether there are long-term benefits from transcatheter interventions in these patients.

Complications of paediatric interventional catheterisation: an analysis of risk factors

OBJECTIVES

To identify predictive factors of complications occurring during paediatric interventional catheterisation.

BACKGROUND

Interventional paediatric catheterisation is still burdened by a substantial risk. Risk factors, however, have rarely been investigated.

METHODS

We analysed prospectively 1,022 interventional procedures performed over a period of 8 years, excluding 260 procedures for atrial septostomy. We considered several patient-related variables, specifically age, weight, and gender, type of procedure, times required for fluoroscopy and the overall procedure, technical challenge, and the severity of the clinical condition. We also analysed variables linked to the environment, specifically the date of the examination, whether the operator remained in training, the novelty of the material, any breakdown in the installation, and errors made by the operator. We classified complications as those without clinical consequence, those which proved lethal, those requiring cardiopulmonary resuscitation, elective or emergency surgery, hospitalisation in the intensive care unit, and those leading to recatheterisation.

RESULTS

Our average incidence of complications was 4.1 per cent, which did not change significantly during the period of study. Of the patients, 4 died, 7 needed urgent surgery, 5 elective surgery, 3 hospitalisation in intensive care unit, and 8 recatheterisation. Independent risk factors for complications were technical challenge, critical clinical condition, operator in training, operator error, and breakdown of the installation. Young age was not associated with a higher risk of complications. Patients in whom no cause for complication could be found, either related to their own features or the environment, had a risk of complication of 1.4 per cent (95 per cent confidence intervals from 0.7 to 2.5 per cent).

CONCLUSIONS

Our data show that variables relating either to the patient or the environment of catheterisation are associated with an increased risk of procedural complications. Knowledge of the risk factors can improve the odds of paediatric interventional catheterisation.

Repetitive paroxysms of supraventricular tachyarrhythmias triggered during pediatric cardiac interventions: suppression after short infusion of amiodarone

Arrhythmias are the most common major complications encountered during pediatric cardiac catheterizations. This report describes the management of repetitive paroxysms of supraventricular tachyarrhythmias triggered by catheter manipulation during interventional procedures in two children. After 15 minutes, amiodarone infusion (25 microg/kg/min) eliminated further paroxysms in both patients, allowing both interventions to be completed safely and effectively.

Impact of Age, Height, and Body Mass Index on Arterial Diameters in Infants and Children:A Model for Predicting Femoral Artery Diameters Prior to Cardiovascular Procedures

PURPOSE

To measure common femoral artery (CFA) diameters in infants and children referred for cardiac catheterization and investigate if CFA diameters can be predicted upon the basis of age, body mass index (BMI), and height.

METHODS

CFA diameters were measured in 84 infants and children (50 boys; age range 1- 220 months) referred for diagnostic or therapeutic cardiac interventions. Sonographic measurements were made in a supine position utilizing a 7.5-MHz linear transducer; diameters were defined as the intima to intima distance. Age was described in months and height in centimeters. The Spearman correlation coefficient (rho) was used to test the similarity of diameters between sides; the Pearson correlation coefficient (r) was used to analyze the influence of age, height, and BMI on CFA diameter.

RESULTS

Diameters of the right and left CFA were similar (rho=0.951). Age and height were highly correlated (rho=0.956), but not BMI and height (rho=0.279). The best model was CFA diameter = -0.838 + 0.031 height + 0.046 BMI. Height was the most relevant determinant for CFA diameter (p<0.0001, 90% CI 0.027 to 0.036; BMI: p=0.093, 90% CI 0.001 to 0.090, and the intercept: p=0.032, 90% CI-1.475 to-0.200).

CONCLUSIONS

Common femoral artery diameter can be sufficiently predicted from height and BMI of infants and children prior to femoral catheterization or surgical reconstruction.

Clinical outcomes and utility of cardiac catheterization prior to superior cavopulmonary anastomosis

OBJECTIVES

We sought to characterize the outcomes of routine catheterization prior to superior cavopulmonary anastomosis and to determine if some patients were unlikely to benefit from catheterization and thus might be evaluated preoperatively with noninvasive methods alone.

BACKGROUND

Congenital heart disease patients with single ventricle physiology undergo routine echocardiography and cardiac catheterization prior to superior cavopulmonary anastomosis to determine anatomic and hemodynamic suitability for this procedure.

METHODS

We performed a retrospective review of all infants (n = 114) evaluated for potential superior cavopulmonary anastomosis at our institution from January 1997 to June 2000.

RESULTS

Patients' median age was 5.5 months. Full echocardiograms were obtained in 79 patients (69%). At catheterization a total of 41 interventions were performed in 35 patients (31%). Twenty-seven patients (24%) were transfused, 18 patients (17%) required cardiac intensive care unit admission, and median length of stay following catheterization was 1 day (range 0 to 22). Complications occurred in 28 patients (25%), most transient. Of 51 patients who had complete echocardiograms without indication for catheterization, none subsequently had significant interventions and only 2 had new findings at catheterization. Three candidates were excluded from operation; all 111 others underwent successful procedures and survived to hospital discharge.

CONCLUSIONS

Interventions were frequent at catheterization prior to superior cavopulmonary anastomosis, but transient complications, transfusion, intensive care unit admission, and prolonged hospital length of stay were common. For patients in whom no issues indicating need for catheterization are identified by echocardiogram, routine catheterization rarely results in new information or intervention. These patients may be more safely evaluated preoperatively using exclusively noninvasive techniques.

Cardiac catheterization of low birth weight infants

The increased survival of low birth weight infants means that more of these infants may be candidates for catheter interventions. There are few data on the results of cardiac catheterization in this group. This study aimed to analyze, retrospectively, cardiac catheterization of infants weighing < or =2.5 kg, with emphasis on the results of interventions. The complication rates of interventional and diagnostic procedures were compared. One hundred eleven catheterizations were performed in 107 patients between 1985 and 1998. Thirty-one procedures were interventional. Balloon atrial septostomy (n = 16), balloon pulmonary valvuloplasty (n = 10), balloon pulmonary angioplasty (n = 1), and coil occlusion of collateral vessels (n = 3) were all performed successfully. One infant (3%) died while undergoing myocardial biopsy. The reintervention rate for isolated pulmonary valve stenosis was 25% (2 of 8) at 1 month, 57% (4 of 7) at 6 months, and 71% (5 of 7) at 1 year. Complications were significantly more frequent during interventional (13 of 31, 42%) than during diagnostic (13 of 80, 16%) procedures. The most common complications during interventions were arrhythmias (3 of 31, 10%) and respiratory deterioration (3 of 31, 10%). Cardiac catheterization was technically feasible in all patients. Balloon pulmonary valvuloplasty and atrial septostomy provided good palliation in this patient group. The mortality of interventional procedures was low. The high incidence of respiratory complications suggests that low birth weight infants should undergo elective ventilation for interventional cardiac catheterization.

Impact of low body weight on frequency of pediatric cardiac catheterization complications

The overall risk of pediatric cardiac catheterization remains low despite the enormous new complexity and potential for complications brought on by the growth of interventional catheterization techniques. For all patients aged < 21 years, balloon interventions carry the highest risk, diagnostic procedures carry more risk than non-balloon interventions, and although weight < or = 5 kg is a significant risk factor for complications, irrespective of the type of procedure performed, weight < or = 2.5 kg did not alter that risk.

Recommendations of the British Paediatric Cardiac Association for therapeutic cardiac catheterisation in congenital cardiac disease

The aims of these recommendations are to improve the outcome for patients after, and to provide acceptable standards of practice of therapeutic cardiac catheterisation performed to treat congenital cardiac disease. The scope of the recommendations includes all interventional procedures, recognising that for some congenital malformations, surgical treatment is equally as effective as, or occasionally preferable to, interventional treatment. The limitations of the recommendations are that, at present, no data are available which compare the results of interventional treatment with surgery, and certainly none which evaluate the numbers and types of procedures that need to be performed for the maintenance of skills. Thus, there is a recognised need to collect comprehensive data with which these recommendations could be reviewed in the future, and re-written as evidence-based guidelines. Such a review will have to take into account the methods of collection of data, their effectiveness, and the latest developments in technology. The present recommendations should, therefore, be considered as consensus statements, and as describing accepted practice, which could be used as a basis for ensuring and improving the quality of future care.

Surgical intervention for complications of transcatheter dilation procedures in congenital heart disease

BACKGROUND

Transcatheter interventions have assumed an important role in the management of many forms of congenital heart disease. While complications of transcatheter interventions are uncommon and usually minor, significant complications requiring operation do occur on occasion. The purpose of this report is to present our experiences with seven such complications, and to review the literature on this topic.

METHODS

Seven patients who required operation after a transcatheter dilation procedure between 1992 and 1998 are described. Three patients required retrieval of retained foreign bodies (stents or balloons), and repair of the underlying abnormality. Two patients underwent repair of fistulas between 2 great vessels, or a great vessel and a cardiac chamber. One patient required operation for a postdilation aneurysm. One patient underwent urgent repair of severe aortic regurgitation after balloon aortic valvuloplasty.

RESULTS

All patients survived and are doing well, with no further need for catheter or operative intervention, from 8 months to 6 years after operation. Additional reported complications requiring operation are discussed as well.

CONCLUSIONS

Operation for complications of catheter interventions in congenital heart disease is seldom necessary. Though uncommon, a variety of such complications may occur, including vascular, valvar, intracardiac, and foreign body complications. When operation is required, results are typically very good.

Acute complications in the current era of therapeutic cardiac catheterization for congenital heart disease

The acute complications of therapeutic cardiac catheterization for congenital heart disease as performed currently in a small unit were reviewed. In recent years, there has been a significant increase in the number of lesions thought amenable to catheter therapy. Only a few reports, however, have addressed the overall incidence of acute complications of therapeutic cardiac catheterization, all representing the experience of centres performing moderate-to-large numbers of procedures. A retrospective review was performed of 425 therapeutic catheter procedures performed at our institution between May 1993 and November 1997. Acute complications were retrieved from the database. This included all adverse events that were clinically recognized at the time of or within 2 weeks after the procedure and which, to the best of the authors' clinical judgement, were related to the catheterization and not part of the natural history of the child's illness. All patients were observed overnight following the procedure, and stayed in hospital if a complication developed. There were 49 acute complications (11.5%), of which 43 (10.1%) were deemed minor and 6 (1.4%) were considered major. The rate was low in patients with valvar pulmonary stenosis, including three neonates (3/45, 6.7%), for those undergoing angioplasty of native co-arctation (1/15, 6.7%) and pulmonary arteries (2/27, 7.4%); and for coil embolization of systemic to pulmonary collateral arteries (1/16, 6.3%). The rate was high in patients with valvar aortic stenosis, including 12 neonates (9/37, 24.3%), and for angioplasty of re-coarctation (4/23, 21.7%). There were more overall complications in neonates (25.6%) than in older patients (10.1%) (p < 0.01). Two patients died (0.5%), but no patient required emergency surgical intervention. In spite of the introduction of many new therapeutic modalities with greater intrinsic risk, and the fact that patients with more complex lesions and who are more acutely ill are being treated, the overall rate of complications remains relatively low. This probably reflects improvements in pericatheterization medical management, in selection of patients, in procedural techniques, and in the experience of operators.

Complications associated with pediatric cardiac catheterization

OBJECTIVES

The aim of this study was to determine the relative risks of pediatric diagnostic, interventional and electrophysiologic catheterizations.

BACKGROUND

The role of the pediatric catheterization laboratory has evolved in the last decade as a therapeutic modality, although remaining an important tool for anatomic and hemodynamic diagnosis.

METHODS

A study of 4,952 consecutive pediatric catheterization procedures was undertaken.

RESULTS

Patient ages ranged from 1 day to 20 years (median 2.9 years). One or more complications occurred in 436 studies (8.8%) and were classified as major in 102 and minor in 458, with vascular complications (n=189; 3.8% of procedures) the most common adverse event. Arrhythmic complications (n=24) were the most common major complication. Death occurred in seven cases (0.14%) as a direct complication of the procedure and was more common in infants (n=5). Independent risk factors for complications included a young patient age and undergoing an interventional procedure.

CONCLUSIONS

Complications continue to be associated with pediatric cardiac catheterization. Efforts should be directed to improving equipment for flexibility and size, and finding alternative methods for vascular access. Patient age and interventional studies are risk factors for morbidity and mortality.

Balloon angioplasty of recurrent coarctation: a 12-year review

OBJECTIVES

This study was undertaken to investigate the long-term outcome of balloon angioplasty for recurrent coarctation of the aorta in a large series of patients.

BACKGROUND

Balloon angioplasty has become the standard treatment for residual or recurrent aortic coarctation. Despite the widespread use of this treatment modality, there are few data outlining the long-term outcome of a large patient cohort.

METHODS

Clinical, echocardiographic, hemodynamic and angiographic data on 90 consecutive patients who underwent balloon angioplasty between January 1984 and January 1996 were reviewed.

RESULTS

Mean systolic pressure gradients were reduced from 31 +/- 21 to 8 +/- 9 mm Hg after dilation (p = 0.0001). The mean diameter of the stenotic site, measured in the frontal and lateral views, increased by 38% and 35%, respectively (p = 0.001). Neurologic events occurred in two patients, with one death. An aortic tear occurred in one patient, requiring surgical intervention. Optimal results were defined as a postprocedure gradient < 20 mm Hg and were obtained acutely in 88% of patients. At long-term follow-up (12 years), 53 (72%) of 74 patients with an early optimal result remained free from reintervention. Transverse arch hypoplasia, defined as an arch dimension < 2 SD below the mean for age, was the primary predictor of the need for reintervention.

CONCLUSIONS

Although the majority of patients undergoing percutaneous balloon angioplasty for recoarctation of the aorta will achieve long-term benefit, the need for further surgical intervention in those with transverse arch hypoplasia remains high.

Evaluation of superficial femoral artery compromise and limb growth retardation after transfemoral artery balloon dilatations

BACKGROUND

Abnormalities of arterial pulse and limb growth after retrograde femoral arterial catheterization have been well documented. However, the magnitude of such complications after transfemoral artery balloon dilatation has not been thoroughly investigated. This study sought to evaluate the prevalence of these abnormalities in children who have undergone transfemoral artery balloon dilatation.

METHODS AND RESULTS

Data on 43 consecutive patients (1 day to 15.5 years old at the time of balloon dilatation) seen on follow-up (42 +/- 23 months) (group 1) were compared with those of 35 patients undergoing retrograde femoral arterial catheterization (group 2) and 47 control patients. Interventional ankle/control ankle blood pressure index (AAI), ratio of interventional/control lower limb length (LLI), and leg length difference (LLD) were measured. Ages and weights at study were similar in all three groups, as were the ages and weights at intervention and duration of follow-up in groups 1 and 2. The AAI was lower (P = .023) in group 1 (0.95 +/- 0.13) than in groups 2 (1.0 +/- 0.1) and 3 (1.01 +/- 0.09). The prevalence of subjects with AAI < or = 0.9 was higher (P = .003) in group 1 than in the other two groups. The LLI and LLD were similar (P > .1) in all three groups. AAI and LLD in the balloon group are not significantly associated with age and weight at intervention, duration of follow-up, or size of the balloon or balloon catheter shaft.

CONCLUSIONS

Transfemoral artery balloon dilatation procedures produce superficial femoral artery compromise, but there was no significant limb growth retardation at a 3.5-year mean follow-up, which may be related to development of collateral circulation. Study of a larger number of children at a longer follow-up interval may be necessary to further confirm these observations.

Transcatheter embolization of coronary artery fistula with controlled release coils

The treatment for large congenital coronary cameral fistulas has been surgical but with advances in interventional catheterization techniques transcatheter embolization of these fistulas with coils or detachable balloons is now possible. This report describes occlusion of a congenital coronary arteriovenous fistula in a 6-year-old girl.

Successful percutaneous double balloon valvuloplasty for congenital mitral stenosis

A 19-month-old infant had an isolated severe 'typical' congenital mitral stenosis with dysplastic valves and two symmetric papillary muscles. He underwent successful double balloon mitral valvuloplasty via the right femoral vein. Left atrium pressure decreased from 30 to 20 mmHg and end diastolic mitral gradient from 12 to 0 mmHg. Cardiac index increased from 4.4 to 6.3 l/min per m2. Gorlin's mitral valve area increased from 1 to 1.7 cm2/m2 and Doppler mitral valve area from 0.9 to 2.2 cm2/m2. At 16 months follow-up, the infant showed sustained clinical improvement.