Congenital Heart Interventions

Cutting balloon angioplasty on branch pulmonary artery stenosis in pediatric patients

Cutting balloon angioplasty on branch pulmonary artery stenosis in pediatric patients. Cobb H, Spray B, Daily J, Dossey A, Angtuaco MJ. Catheter Cardiovasc Interv. 2021 Sep;98(3):526-532. doi: 10.1002/ccd.29803. Epub 2021 Jun 10. PMID: 34110668   Take Home Points: Cutting balloon angioplasty (CBA) for pulmonary artery stenosis (PAS) shows moderate medium-term success. Patients with TOF/PA/MAPCAs and especially those with genetic syndromes associated with PAS (Williams, Alagille, or arterial tortuosity syndrome) are significantly less likely to have a lasting success following CBA. Choosing a maximal balloon diameter as the smallest of either 150% of the distal vessel or 300% of the minimal luminal diameter is associated with sustained success following CBA. Commentary from Dr. Prsa Milan (Switzerland, Europe), section editor of Congenital Heart Disease Interventions Journal Watch: Cutting balloon angioplasty (CBA) has been used successfully to treat PAS resistant to standard pressure balloons. However, there is little data on long-term outcomes. The authors of this study describe the longest follow-up to date of CBA in PAS at a single institution and identify predictors of a successful outcome.   From 2005 to 2020, 44 patients (median age 20 months and weight 12.4 kg) underwent 148 CBAs on 116 unique pulmonary artery segments. The mean ratio of cutting balloon diameter to minimal luminal diameter (MLD) was 2.51 ± 1.06 (range 1.0-8.0). There was good initial success (≥50% increase in MLD) with an average immediate increase in MLD of 57.3% (CI, 39.0%-75.6%). In addition, there was sustained improvement at a mean follow-up time of 34.3 months (CI, 0-142 months) with an average increase in MLD of 78.7% (CI, 44%-114%). Complications included reperfusion injury in three patients and pulmonary hemorrhage in two, one of whom died from acute pulmonary artery rupture. Unsurprisingly, interventions were less successful in patients with TOF/PA/MAPCAs and those with genetic syndromes associated with branch PAS (Williams, Alagille, or ATS), as shown by the Kaplan-Meier curves in Figure 3.     Figure 3. Freedom from reintervention following CBA for all pulmonary artery segments in patients with TOF/PA/MAPCAs, genetic syndromes associated with PAS, and those without either diagnosis.   Multivariable logistic regression analysis confirmed that not having TOF/PA/MAPCAs and genetic syndromes increased the odds of a successful CBA by 70% (OR 0.30, CI 0.11-0.79, p = 0.01) and 91% (OR 0.09, CI 0.02-0.56, p = 0.01), respectively. Moreover, each increase in the maximum cutting balloon-to-MLD ratio by 0.5 improved the odds of success by a factor of 2.37 (CI 1.7-3.3, p = <0.0001).   This study further establishes CBA as a successful therapy for PAS resistant to conventional angioplasty. It also highlights two specific patient populations that remain difficult to manage. In TOF/PA/MAPCAs, PA stenoses may be very distal, long-segment lesions, at bifurcation points, or due to scarring at sites of surgical interventions. These patients may thus warrant earlier, more frequent and more aggressive catheterization. In Williams, Alagille and ATS, the abnormal arterial wall structure may prevent therapeutic tears required for a successful dilatation, and these patients may benefit more from surgical intervention instead.    

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Impact of Transcatheter Pulmonary Artery Intervention Following Superior Cavo-pulmonary Connection on Pulmonary Artery Growth

Impact of Transcatheter Pulmonary Artery Intervention Following Superior Cavo-pulmonary Connection on Pulmonary Artery Growth. Chaszczewski KJ, Huang J, Fuller S, Smith CL, Dori Y, Glatz AC, Gillespie MJ, Rome JJ, O'Byrne ML. World J Pediatr Congenit Heart Surg. 2021 Sep;12(5):635-642. doi: 10.1177/21501351211033238.PMID: 34597205   Take Home Points: Approximately 11% of patients developed branch pulmonary artery stenosis deemed significant enough to require intervention in this single center study. Balloon and stent angioplasty of pulmonary artery stenosis following superior cavo-pulmonary connection normalizes distal pulmonary artery growth relative to the unaffected branch pulmonary artery. Commentary from Dr. Ryan Romans (Kansas City, MO), section editor of Congenital Heart Disease Interventions Journal Watch: Branch pulmonary artery (PA) stenosis is a common residual lesion following superior cavo-pulmonary connection (SCPC) that is performed as part of single ventricle palliation. Widely patent pulmonary vasculature is considered essential to long-term success with single ventricle palliation. Transcatheter therapy (balloon angioplasty or stent angioplasty) is the first line treatment for branch PA stenosis following SCPC. Previous studies have demonstrated favorable short- and long-term results with this. The authors in this study sought to determine how well branch PAs grow following intervention by comparing its growth rate to the unaffected branch PA. In order to do this, they retrospectively measured the distal branch pulmonary artery (DBPA) and lower lobe branch (LLB) in the affected PA and unaffected PA immediately following intervention and looked at the PA growth rate by performing the same measurements at subsequent cardiac catheterizations.   From January 2010-December 2018; 391 patients underwent SCPC and met inclusion criteria (bilateral bidirectional Glenn, previous hybrid palliation, 1.5 ventricle repair, and SCPC to one PA and systemic to pulmonary shunt to contralateral PA were excluded). 35 patients underwent a total of 54 unilateral transcatheter PA interventions (15 balloon angioplasty, 20 stent angioplasty) at a median of 70 days following SCPC (IQR 19-297) with those undergoing stent angioplasty occurring earlier in the post operative period. The narrowest segment was smaller in those who underwent stent angioplasty (2.2 ± 1 mm) versus balloon angioplasty (3.3 ± 1 mm) as was the DBPA raw measurement (4.2 ± 1.3 mm versus 5.6 ± 1.7 mm) and when indexed for body surface area (15.0 ± 10.1 mm/m2 versus 26.9 ± 15.2 mm/m2). 24 patients underwent subsequent cardiac catheterization prior to total cavopulmonary connection (i.e. Fontan) and had angiography available for serial PA measurements. There was growth of the DBPA and LLB in the treated and untreated branch PA in both the raw dimension and relative to body surface are. There was not significant difference in the growth rate between the unaffected PA and the treated PA.   The authors in this single center retrospective study conclude that distal pulmonary vasculature grows at a similar rate in PA branches requiring intervention versus those that do not in the short term (see below figure). While this model is not perfect, randomizing patients to receive or not receive PA interventions to compare growth is not realistic. This supports the idea that transcatheter intervention helps promote normal growth velocity in treated branch PAs. This is important not only for the central vessel but is likely important for the distal pulmonary vasculature to continue to grow and develop.     Figure 2. Graphical depiction of longitudinal pulmonary artery (PA) growth over time, measured at distal branch PA (DBPA) of the treated PA (A) and DBPA of the contralateral, untreated PA (B).   

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