Phillip Moore

Midterm results of balloon dilation of congenital aortic stenosis: predictors of success.

OBJECTIVESnWe evaluated patient and procedural characteristics that influence the midterm success of balloon dilation of congenital aortic stenosis.nnnBACKGROUNDnBalloon dilation is a new treatment for congenital aortic stenosis. Factors that influence midterm success are unknown.nnnMETHODSnWe performed a retrospective review of 148 children >1 month old who underwent balloon dilation for aortic stenosis.nnnRESULTSnBalloon dilation was successful in 87% of patients, with a procedural mortality rate of 0.7%. The average immediate peak to peak gradient reduction was 56.4 +/- 19.9% (mean +/- SD). Prior valvotomy was the only factor that significantly reduced the immediate gradient reduction after dilation (47.1 +/- 21.8% vs. 57.8 +/- 19.6%, p < 0.01). Survival after dilation was 95% at 8 years. Seventy-five percent of patients were free of repeat intervention 4 years after dilation, whereas 50% remained free of repeat intervention at 8 years. Asymmetrically thick valve leaflets (risk ratio [RR] 0.17, p < 0.01) and prior aortic valvotomy (RR 0.35, p = 0.02) decreased the risk of repeat intervention. Aortic regurgitation grade > or = 3 (RR 4.27, p = 0.04) and residual gradient after dilation (RR 1.63 for 10 mm Hg, p < 0.01) increased the risk.nnnCONCLUSIONSnThe 8-year survival rate after dilation was 95% with 50% of patients free of repeat intervention. Factors that increased the risk for repeat intervention included symmetrically thin or thick aortic valve leaflets, regurgitation grade > or = 3 after dilation and a high residual gradient after dilation. The incidence of repeat intervention after dilation was high owing to its palliative nature.

Intermediate follow‐up following intravascular stenting for treatment of coarctation of the aorta

Background: We report a multiinstitutional study on intermediate‐term outcome of intravascular stenting for treatment of coarctation of the aorta using integrated arch imaging (IAI) techniques. Methods and Results: Medical records of 578 patients from 17 institutions were reviewed. A total of 588 procedures were performed between May 1989 and Aug 2005. About 27% (160/588) procedures were followed up by further IAI of their aorta (MRI/CT/repeat cardiac catheterization) after initial stent procedures. Abnormal imaging studies included: the presence of dissection or aneurysm formation, stent fracture, or the presence of reobstruction within the stent (instent restenosis or significant intimal build‐up within the stent). Forty‐one abnormal imaging studies were reported in the intermediate follow‐up at median 12 months (0.5–92 months). Smaller postintervention of the aorta (CoA) diameter and an increased persistent systolic pressure gradient were associated with encountering abnormal follow‐up imaging studies. Aortic wall abnormalities included dissections (n = 5) and aneurysm (n = 13). The risk of encountering aortic wall abnormalities increased with larger percent increase in CoA diameter poststent implant, increasing balloon/coarc ratio, and performing prestent angioplasty. Stent restenosis was observed in 5/6 parts encountering stent fracture and neointimal buildup (n = 16). Small CoA diameter poststent implant and increased poststent residual pressure gradient increased the likelihood of encountering instent restenosis at intermediate follow‐up. Conclusions: Abnormalities were observed at intermediate follow‐up following IS placement for treatment of native and recurrent coarctation of the aorta. Not exceeding a balloon:coarctation ratio of 3.5 and avoidance of prestent angioplasty decreased the likelihood of encountering an abnormal follow‐up imaging study in patients undergoing intravascular stent placement for the treatment of coarctation of the aorta. We recommend IAI for all patients undergoing IS placement for treatment of CoA.

Transvascular Balloon Dilation for Neonatal Critical Aortic Stenosis: Early and Midterm Results

OBJECTIVESnWe evaluated our immediate and midterm (mean 4.3 years) results of balloon dilation of critical valvular aortic stenosis in 33 neonates.nnnBACKGROUNDnBalloon dilation has been used as an alternative to surgical treatment. Reports to date consist of small series (largest 16 babies) with short-term follow-up (longest 4.8 years).nnnMETHODSnFrom 1985 to 1991, 33 neonates had dilation at a mean age of 13 days and a mean weight of 3.4 kg. Nineteen of the neonates (58%) were intubated and received prostaglandins, and 94% had other cardiac abnormalities.nnnRESULTSnThe dilation was completed retrograde in 31 of the neonates (umbilical artery in 11 and femoral artery in 20) and anterograde (femoral vein) in 2. The average immediate peak gradient and left ventricular end-diastolic pressure reductions were 54% and 20%, respectively. The overall mortality rate was 12% (three early deaths and one late). All 20 neonates dilated through a femoral artery initially had pulse loss with restoration in 35% after thrombolytic therapy. At 8.3 years, survival and freedom of reintervention probability rates were 88% and 64%, respectively. At mean 4.3 years of follow-up, 83% of the survivors were asymptomatic; Doppler study revealed a maximal instantaneous gradient < 50 mm Hg in 65% of neonates and significant aortic regurgitation in 14%.nnnCONCLUSIONSnThis study confirms that dilation of aortic stenosis in neonates is effective; reintervention (mostly redilation) is frequent (40%); and midterm survival is encouraging (88%).

Severe congenital mitral stenosis in infants.

BACKGROUNDnDespite current medical and surgical therapy, infants with symptomatic congenital mitral stenosis (CMS) continue to have high rates of morbidity and mortality. Catheter balloon dilation has been successful in relieving symptoms in a few older children with CMS but has not been evaluated in infants.nnnMETHODS AND RESULTSnWe reviewed the records of 85 infants with CMS to assess severity of CMS, associated cardiac lesions, echocardiographic morphological appearance of the mitral valve, treatment, and outcome. There were five valve morphologies identified: typical hypoplastic mitral valve with symmetric papillary muscles (SYMM, 52%), supravalvar mitral ring (SVMR, 20%), double-orifice mitral valve (DOMV, 11%), hypoplastic mitral valve with asymmetric papillary muscles (ASYMM, 8%), and parachute mitral valve (PARA, 8%). Of the 85 infants, 31 (36%) were severely symptomatic, requiring intervention within the first 2 years. Balloon dilation was performed in 18 infants (age, 8.7 +/- 5.7 months; weight, 5.9 +/- 1.9 kg) and valve surgery in 13 (age, 10.9 +/- 5.9 months; weight, 6.7 +/- 2.1 kg). Balloon dilation decreased the peak transmitral gradient (LAa-LVED) > 30% in 15 of 18 initial attempts, from 20.3 +/- 8.2 to 10.9 +/- 4.9 mm Hg (P < .001), and the mitral valve area increased from 0.7 +/- 0.3 to 1.0 +/- 0.5 cm2/M2 (n = 10, P = .01). No infants died during the initial balloon dilation, although 2 of 3 died during a repeat procedure for restenosis. Other complications included significant mitral regurgitation in 7 of 18 patients (39%), 4 of whom had SVMR. Of the 18 infants, 8 (44%) had persistent symptomatic improvement at a mean follow-up of 14 months (range, 2 to 32 months). The 2-year survival after balloon dilation was 70%; 40% remained free of repeat intervention. Mitral valve surgery in 13 infants consisted of SVMR resections in 7, mitral valve replacements in 4, and LA-to-LV aortic valved homografts in 2. The operative mortality was 30%. Sustained improvement occurred in 8 (6 with SVMR) at 11 to 62 months of follow-up (mean, 30 months), with a 2-year survival of 60%.nnnCONCLUSIONSnInfants with severe CMS have 2-year mortality rates approaching 40% regardless of treatment modality. Balloon dilation significantly reduces the transmitral gradient in the majority, but symptomatic improvement persists in only 40%. Procedure-related mortality was associated with repeat balloon dilation in patients with left ventricular hypoplasia. Balloon dilation of typical CMS can provide symptomatic relief in many infants, allowing postponement of valve replacement, although infants with SVMR do better with surgical management.

Use and Performance of the Melody Transcatheter Pulmonary Valve in Native and Postsurgical, Nonconduit Right Ventricular Outflow Tracts

Background—Melody Transcatheter Pulmonary Valve (TPV) replacement therapy represents an important advance in congenital cardiovascular interventions. The off-label extension of the Melody TPV to patients with nonconduit outflow tracts (right ventricular outflow tract [RVOT]) has the potential to vastly expand the population of patients eligible to benefit from nonsurgical restoration of RVOT function. However, knowledge on the performance of the Melody TPV in this setting is limited. Methods and Results—This is a multicenter, retrospective review of the Melody TPV when placed in nonconduit RVOTs, in which at least a portion of the circumference was composed of native tissue. Five centers contributed data on 31 patients. The median age at implantation was 24 years (range, 7–66). At a median follow-up of 15 months, all patients were alive. No patient had greater than mild TPV insufficiency, and the median maximum instantaneous gradients across the RVOT was 23 mm Hg. Stent fracture occurred in 32%. Eight patients developed more than mild TPV obstruction, of whom 6 were associated with identified stent fracture. Three patients developed blood stream infections. There were 5 reinterventions in 3 patients, including 3 repeat TPV implantations and 2 TPV explantations. Conclusions—Melody TPV implantation is feasible in selected patients with RVOTs comprised solely or predominantly native tissue and has the potential to expand the population of patients eligible to benefit from nonsurgical restoration of RVOT function. In early follow-up, valve competency seems preserved. The dominant mechanism of valve dysfunction seems to be related to stent fracture with recurrent obstruction. Additional data are necessary to better understand how to safely expand TPV therapy to this population.

Clinical course and hemodynamic observations after supraannular mitral valve replacement in infants and children.

OBJECTIVESnWe report the clinical course and unique hemodynamic findings after placement of a supraannular mitral valve prosthesis.nnnBACKGROUNDnChildren with symptomatic mitral valve disease whose annulus is too small for the smallest prosthesis are difficult to manage. One option is valve replacement with a prosthesis positioned entirely within the left atrium (LA).nnnMETHODSnWe reviewed 17 patients (median age 10 months) with symptomatic mitral valve disease who underwent placement of a supraannular valve prosthesis between 1980 and 1994.nnnRESULTSnThe actuarial survival rates were 88% at 1 month and 71%, 62% and 53% at 1, 2 and 10 years, respectively. Preoperative hemodynamic data (mean +/- SD)) compared with those after placement of the supraannular mitral prosthesis were as follows: a wave to left ventricular end-diastolic pressure gradient 17 +/- 5 versus 4 +/- 4 mm Hg (p = 0.003), mean LA pressure 25 +/- 6 versus 20 +/- 6 mm Hg (p = 0.07), a wave 30 +/- 6 versus 19 +/- 5 mm Hg (p = 0.006), v wave 28 +/- 5 versus 30 +/- 9 mm Hg (p = 0.31), mean pulmonary artery pressure 54 +/- 19 versus 42 +/- 15 mm Hg (p = 0.07) and left ventricular end-diastolic pressure 14 +/- 5 versus 16 +/- 4 mm Hg (p = 0.12).nnnCONCLUSIONSnSupraannular mitral valve replacement provides relief of mitral stenosis or mitral regurgitation. However, LA to left ventricular early diastolic gradients with large atrial v waves contribute to elevated mean LA pressures in the absence of prosthetic valve obstruction or regurgitation. As a result of this unexpected finding, associated left heart obstructive lesions and pulmonary and left ventricular end-diastolic hypertension, the outlook remains poor.

Intraaortic Spring Coil Loops: Early and Late Results.

OBJECTIVESnOur aim was to determine the late fate of intraaortic spring coil loops after embolization of aortopulmonary vessels.nnnBACKGROUNDnIn some aortopulmonary collateral vessels and patent ductus arteriosi, the narrowest segment is close to the aorta; coils used to close such vessels will straddle the lesion, allowing one or more coil loops to protrude into the aortic lumen. The consequences of this procedure are unknown.nnnMETHODSnWe reviewed the cineangiograms of all patients who had at least one aortopulmonary collateral vessel or patent ductus arteriosus closure between January 1, 1988 and August 31, 1993. From this group, 53 patients had multiple-plane angiographic evidence of intraaortic coil loops. All subsequent cineangiograms were reviewed to determine coil position or movement and evidence of recanalization or endothelial coverage of the coil loop. We also reviewed each hospital record or communicated directly with referring physicians to identify any subsequent complications such as emboli or endocarditis.nnnRESULTSnOf the 53 patients with intraaortic coil loops, 49 patients had closure of one or more aortopulmonary collateral vessels (59 vessels), and 4 had closure of a patient ductus arteriosus (4 vessels). Patient follow-up ranged from 1 day to 66 months (median 20 months); follow-up was not available in 6 patients. Five of the 53 patients (9.3%; 95% confidence limits [CL] 3.1% to 20.7%) died at operation or of end-stage heart failure. Patients with late angiography had no residual flow in 31 of 35 aortopulmonary collateral vessels (88.6%; 95% CL 73.3% to 96.8%), and 0.5 mm separated the coil and aortic contrast column in all 12 coils with adequate angiography, suggesting endothelial coverage of the intraaortic coil loop. No episodes of stroke, embolic events, endocarditis or coil migration were reported.nnnCONCLUSIONSnAlthough coil occlusion of aortopulmonary collateral vessels or patent ductus arteriosi may produce intraaortic coil loops, endothelialization appears routine. No late complications associated with intraaortic coil loops were observed.

CRISP: Catheterization RISk score for pediatrics: A Report from the Congenital Cardiac Interventional Study Consortium (CCISC)

We sought to develop a scoring system that predicts the risk of serious adverse events (SAEs) for individual pediatric patients undergoing cardiac catheterization procedures.

Catheter Intervention: Balloon Angioplasty

Dotter and Judkins first described transluminal angioplasty in 1964 (1). Using a surgical cutdown, they introduced solid cylindrical dilators of sequentially increasing diameters to enlarge the vessel lumen of iliac and femoral arteries. Ten years later Gruentzig (2) successfully applied Dotter’s concept to a percutaneously placed inflatable noncompliant balloon, demonstrating effective dilation of iliac and femoral arteries. In 1975 the technique was applied to the coronary arteries (3). At that time, the prevailing hypothesis of the mechanism of vessel enlargement was redistribution of soft atheromatous plaque. Pediatric cardiologists were therefore slow to apply the technique to congenital vessel stenoses. Animal studies in the early 80s(4,5,6) showed the mechanism of vessel enlargement by angioplasty to be intimai and medial injury with presumed healing in an open position; the door opened to the rapid application of balloon angioplasty to a variety of congenital vascular stenoses. In a trio of case reports in 1982, Singer et al. reported angioplasty of a coarctation in an infant(7), Driscoll et al. unsuccessfully dilated pulmonary vein stenosis(8), and Rocchini et al. treated SVC obstruction(9). By 1983 the technique had been successfully applied by Lock and colleagues to series of patients with pulmonary artery stenosis, coarctation, and venous stenosis including atrial baffle obstruction (10,11,12).

Modeling Major Adverse Outcomes of Pediatric and Adult Patients With Congenital Heart Disease Undergoing Cardiac Catheterization: Observations From the NCDR IMPACT Registry (National Cardiovascular Data Registry Improving Pediatric and Adult Congenital Treatment)

Background: Risk standardization for adverse events after congenital cardiac catheterization is needed to equitably compare patient outcomes among different hospitals as a foundation for quality improvement. The goal of this project was to develop a risk-standardization methodology to adjust for patient characteristics when comparing major adverse outcomes in the NCDR’s (National Cardiovascular Data Registry) IMPACT Registry (Improving Pediatric and Adult Congenital Treatment). Methods: Between January 2011 and March 2014, 39u2009725 consecutive patients within IMPACT undergoing cardiac catheterization were identified. Given the heterogeneity of interventional procedures for congenital heart disease, new procedure-type risk categories were derived with empirical data and expert opinion, as were markers of hemodynamic vulnerability. A multivariable hierarchical logistic regression model to identify patient and procedural characteristics predictive of a major adverse event or death after cardiac catheterization was derived in 70% of the cohort and validated in the remaining 30%. Results: The rate of major adverse event or death was 7.1% and 7.2% in the derivation and validation cohorts, respectively. Six procedure-type risk categories and 6 independent indicators of hemodynamic vulnerability were identified. The final risk adjustment model included procedure-type risk category, number of hemodynamic vulnerability indicators, renal insufficiency, single-ventricle physiology, and coagulation disorder. The model had good discrimination, with a C-statistic of 0.76 and 0.75 in the derivation and validation cohorts, respectively. Model calibration in the validation cohort was excellent, with a slope of 0.97 (standard error, 0.04; P value [for difference from 1] =0.53) and an intercept of 0.007 (standard error, 0.12; P value [for difference from 0] =0.95). Conclusions: The creation of a validated risk-standardization model for adverse outcomes after congenital cardiac catheterization can support reporting of risk-adjusted outcomes in the IMPACT Registry as a foundation for quality improvement.