Physician-Modified Endograft-Facilitated Transcatheter Pulmonary Valve Replacement in Large Right Ventricular Outflow Tract.

BACKGROUND: Transcatheter pulmonary valve replacement (TPVR) in patients with a congenital or acquired abnormality resulting in enlarged right ventricular outflow tract (RVOT) is challenging and may preclude treatment with dedicated devices. We describe a technique using a physician-modified endograft to facilitate TPVR. METHODS: Six patients underwent physician-modified endograft-facilitated TPVR for severe symptomatic pulmonary insufficiency with enlarged RVOT. The fenestration was created in a commercially available endograft before implantation, which was then deployed from the dominant branch pulmonary artery into the RVOT, with the fenestration aligned with the ostium of the nondominant pulmonary artery. A covered stent was placed through the fenestration into the nondominant branch pulmonary artery, and a transcatheter heart valve was deployed within the endograft at the level of the original pulmonary valve. RESULTS: Four patients had tetralogy of Fallot, 1 had pulmonary atresia, and 1 had rheumatic valve disease. The RVOT/main pulmonary artery was severely enlarged (diameter, 44.2 [43.5-50.6] mm). All patients had reduced right ventricular (RV) function and dilated RVs (RV end-diastolic volume, 314 [235-316] mL). Successful endograft, covered stent, and transcatheter heart valve deployment were achieved in all cases without stent/valve embolization, vascular complications, or bleeding complications. At 30 days, 1 patient had mild pulmonary insufficiency, while others had none. The RV size measured by echocardiography was significantly reduced after TPVR (RV area, 34.4 [baseline] versus 29.0 [pre-discharge] versus 25.3 [30 days] cm2; P=0.03). During median follow-up of 221.5 (range, 29-652) days, there were no deaths or need for pulmonary valve reintervention. One patient developed severe tricuspid regurgitation due to entrapment of the anterior tricuspid leaflet by the endograft. The patient underwent successful tricuspid replacement and resection of the offending endograft with preservation of the pulmonary valve prosthesis. CONCLUSIONS: Simple fenestration of an off-the-shelf endograft and associated covered stent placement through the fenestration allows TPVR for patients with dysfunctional native or patch-repaired pulmonary valves and RVOT enlargement.

Transcatheter Recanalization of Atretic Pulmonary Veins in Infants and Children.

BACKGROUND: Pulmonary vein stenosis is a progressive disease associated with a high rate of mortality in children. If left untreated, myofibroblastic proliferation can lead to pulmonary vein atresia (PVA). In our experience, transcatheter recanalization has emerged as a favorable interventional option. We sought to determine the acute success rate of recanalization of atretic pulmonary veins and mid-term outcomes of individual veins after recanalization. METHODS: We reviewed all patients with PVA at our institution between 2008 and 2020 diagnosed by either catheterization or cardiac computed tomography. All veins with successful recanalization were reviewed and procedural success rate and patency rate were noted. Competing risk analysis was performed to demonstrate outcomes of individual atretic veins longitudinally. RESULTS: Between 2008 and 2020, our institution diagnosed and treated 131 patients with pulmonary vein stenosis. Of these, 61 patients developed atresia of at least one pulmonary vein. In total, there were 97 atretic pulmonary veins within this group. Successful recanalization was accomplished in 47/97 (48.5%) atretic veins. No atretic pulmonary veins were successfully recanalized before 2012. The majority of veins were recanalized between 2017 and 2020-39/56 (70%). The most common intervention after recanalization was drug-eluting stent placement. At 2-year follow-up 42.6% of recanalized veins (20.6% of all atretic veins) remained patent with a median of 4 reinterventions per person. CONCLUSIONS: Transcatheter recanalization of PVA can result in successful reestablishment of flow to affected pulmonary veins in many cases. Drug-eluting stent implantation was the most common intervention performed immediately post-recanalization. Vein patency was maintained in 42.6% of patients at 2-year follow-up from recanalization with appropriate surveillance and reintervention. Overall, only a small portion of atretic pulmonary veins underwent successful recanalization with maintained vessel patency at follow-up. Irrespective of successful recanalization, there was no detectable survival difference between the more recently treated PVA cohort and non-PVA cohort.

Retrograde Pulmonary Vein Recanalization Using Transcatheter Electrosurgery.

Transcatheter electrosurgery is a wire-based technique used to traverse or cut tissue within blood-filled spaces using alternating current delivered by guidewires or catheters. The use of transcatheter electrosurgical techniques in the pediatric population has been limited. We are reporting the first case of retrograde pulmonary vein recanalization using transcatheter electrosurgery. (Level of Difficulty: Advanced.).

Thrombolysis in Children: A Case Report and Review of the Literature.

Thromboembolism (TE), including venous thromboembolism (VTE), arterial TE, arterial ischemic stroke (AIS), and myocardial infarction (MI), is considered a relatively rare complication in the pediatric population. Yet, the incidence is rising, especially in hospitalized children. The vast majority of pediatric TE occurs in the setting of at least one identifiable risk factor. Most recently, acute COVID-19 and multisystem inflammatory syndrome in children (MIS-C) have demonstrated an increased risk for TE development. The mainstay for the management pediatric TE has been anticoagulation. Thrombolytic therapy is employed more frequently in adult patients with ample data supporting its use. The data for thrombolysis in pediatric patients is more limited, but the utilization of this therapy is becoming more commonplace in tertiary care pediatric hospitals. Understanding the data on thrombolysis use in pediatric TE and the involved risks is critical before initiating one of these therapies. In this paper, we present the case of an adolescent male with acute fulminant myocarditis and cardiogenic shock likely secondary to MIS-C requiring extracorporeal life support (ECLS) who developed an extensive thrombus burden that was successfully resolved utilizing four simultaneous catheter-directed thrombolysis (CDT) infusions in addition to a review of the literature on the use of thrombolytic therapy in children.

Single-Barrel, Double-Barrel, and Fenestrated Endografts to Facilitate Transcatheter Pulmonary Valve Replacement in Large RVOT.

OBJECTIVES: The aim of this study was to test the hypothesis that narrowing the landing zone using commercially available endografts would enable transcatheter pulmonary valve replacement (TPVR) using commercially available transcatheter heart valves. BACKGROUND: TPVR is challenging in an outsized native or patch-repaired right ventricular outflow tract (RVOT). Downsizing the RVOT for TPVR is currently possible only using investigational devices. In patients ineligible because of excessive RVOT size, TPVR landing zones were created using commercially available endografts. METHODS: Consecutive patients with native or patch-repaired RVOTs and high or prohibitive surgical risk were reviewed, and this report describes the authors' experience with endograft-facilitated TPVR (EF-TPVR) offered to patients ineligible for investigational or commercial devices. All EF-TPVR patients were surgery ineligible, with symptomatic, severe pulmonary insufficiency, enlarged RVOTs, and severe right ventricular (RV) enlargement (>150 ml/m2). TPVR and surgical pulmonary valve replacement (SPVR) were compared in patients with less severe RV enlargement. RESULTS: Fourteen patients had large RVOTs unsuitable for conventional TPVR; 6 patients (1 surgery ineligible) received investigational devices, and 8 otherwise ineligible patients underwent compassionate EF-TPVR (n = 5 with tetralogy of Fallot). Three strategies were applied on the basis of progressively larger RVOT size: single-barrel, in situ fenestrated, and double-barrel endografts as required to anchor 1 (single-barrel and fenestrated) or 2 (double-barrel) transcatheter heart valves. All were technically successful, without procedure-related, 30-day, or in-hospital deaths. Two late complications (stent obstruction and embolization) were treated percutaneously. One patient died of ventricular tachycardia 36 days after EF-TPVR. Compared with 48 SPVRs, RV enlargement was greater, but 30-day and 1-year mortality and readmission were no different. The mean transvalvular pressure gradient was lower after EF-TPVR (3.8 ± 0.8 mm Hg vs. 10.7 ± 4.1 mm Hg; p < 0.001; 30 days). More than mild pulmonary insufficiency was equivalent in both (EF-TPVR 0.0% [n = 0 of 8] vs. SPVR 4.3% [n = 1 of 43]; p = 1.00; 30 days). CONCLUSIONS: EF-TPVR may be an alternative for patients with pulmonic insufficiency and enlarged RVOTs ineligible for other therapies.

Risk Factors for Red Blood Cell Transfusions in Children Undergoing Cardiac Catheterization.

OBJECTIVE: To identify risk factors associated with risk of red blood cell transfusions (RBCTs) following pediatric cardiac catheterizations. STUDY DESIGN: We performed a review of all pediatric cardiac catheterizations from 2012 to 2017. The primary endpoint was RBCT within 72 hours of pediatric cardiac catheterization. Patient and procedural factors were reviewed. Generalized linear modelling was performed to describe interactions among relevant risk factors. RESULTS: In total, 831 RBCTs occurred within 72 hours of 6028 pediatric cardiac catheterizations (13.8%). Univariate analysis revealed that the prevalence of RBCT was highest among infants (37.6% incidence of RBCT) and among those with higher estimated blood loss as a percent of blood volume (P = .03). Among infants, multivariate analysis revealed that weight (OR 0.72; 95% CI 0.63-0.81), complex 2-ventricle (OR 3.14, 95% CI 2.18-4.57), and single ventricle status (OR 5.21, 95% CI 3.42-8.01) were associated with risk of RBCT. Inpatient infants from intensive care (OR 4.74; 95% CI 3.49-6.49) or stepdown units (OR 2.33; 95% CI 1.58-3.46) were at higher risk. Length of procedure (OR 2.57; 95% CI 2.03-3.26) and oxygen saturation (OR 0.98; 95% CI 0.97-0.99; P < .01) were also associated with RBCTs. CONCLUSIONS: Hospitalized infants with single ventricle or complex 2-ventricle anatomy are at highest risk of RBCT. Length of procedure, blood loss, and oxygen saturations are additional risk factors associated with RBCT. Operators should consider these factors when planning pediatric cardiac catheterizations, particularly when exposure to RBCT is undesirable.

Thromboprophylaxis strategies for children with single-ventricle circulations (superior or total cavo-pulmonary connections) after stent implantation.

OBJECTIVE: To define optimal thromboprophylaxis strategy after stent implantation in superior or total cavopulmonary connections. BACKGROUND: Stent thrombosis is a rare complication of intravascular stenting, with a perceived higher risk in single-ventricle patients. METHODS: All patients who underwent stent implantation within superior or total cavopulmonary connections (caval vein, innominate vein, Fontan, or branch pulmonary arteries) were included. Cohort was divided into aspirin therapy alone versus advanced anticoagulation, including warfarin, enoxaparin, heparin, or clopidogrel. Primary endpoint was in-stent or downstream thrombus, and secondary endpoints included bleeding complications. RESULTS: A total of 58 patients with single-ventricle circulation underwent 72 stent implantations. Of them 14 stents (19%) were implanted post-superior cavopulmonary connection and 58 (81%) post-total cavopulmonary connection. Indications for stenting included vessel/conduit stenosis (67%), external compression (18%), and thrombotic occlusion (15%). Advanced anticoagulation was prescribed for 32 (44%) patients and aspirin for 40 (56%) patients. Median follow up was 1.1 (25th-75th percentile, 0.5-2.6) years. Echocardiograms were available in 71 patients (99%), and advanced imaging in 44 patients (61%). Thrombosis was present in two patients on advanced anticoagulation (6.3%) and none noted in patients on aspirin (p = 0.187). Both patients with in-stent thrombus underwent initial stenting due to occlusive left pulmonary artery thrombus acutely post-superior cavopulmonary connection. There were seven (22%) significant bleeding complications for advanced anticoagulation and none for aspirin (p < 0.001). CONCLUSIONS: Antithrombotic strategy does not appear to affect rates of in-stent thrombus in single-ventricle circulations. Aspirin alone may be sufficient for most patients undergoing stent implantation, while pre-existing thrombus may warrant advanced anticoagulation.

3-Year Outcomes of the Edwards SAPIEN Transcatheter Heart Valve for Conduit Failure in the Pulmonary Position From the COMPASSION Multicenter Clinical Trial.

OBJECTIVES: This study provides the 3-year follow-up results of the COMPASSION (Congenital Multicenter Trial of Pulmonic Valve Regurgitation Studying the SAPIEN Transcatheter Heart Valve) trial. Patients with moderate to severe pulmonary regurgitation and/or right ventricular outflow tract conduit obstruction were implanted with the SAPIEN transcatheter heart valve (THV). BACKGROUND: Early safety and efficacy of the Edwards SAPIEN THV in the pulmonary position have been established through a multicenter clinical trial. METHODS: Eligible patients were included if body weight was >35 kg and in situ conduit diameter was ≥16 and ≤24 mm. Adverse events were adjudicated by an independent clinical events committee. Three-year clinical and echocardiographic outcomes were evaluated in these patients. RESULTS: Fifty-seven of the 63 eligible patients were accounted for at the 3-year follow-up visit from a total of 69 implantations in 81 enrolled patients. THV implantation was indicated for pulmonary stenosis (7.6%), regurgitation (12.7%), or both (79.7%). Twenty-two patients (27.8%) underwent implantation of 26-mm valves, and 47 patients received 23-mm valves. Functional improvement in New York Heart Association functional class was observed in 93.5% of patients. Mean peak conduit gradient decreased from 37.5 ± 25.4 to 17.8 ± 12.4 mm Hg (p < 0.001), and mean right ventricular systolic pressure decreased from 59.6 ± 17.7 to 42.9 ± 13.4 mm Hg (p < 0.001). Pulmonary regurgitation was mild or less in 91.1% of patients. Freedom from all-cause mortality at 3 years was 98.4%. Freedom from reintervention was 93.7% and from endocarditis was 97.1% at 3 years. There were no observed stent fractures. CONCLUSIONS: Transcatheter pulmonary valve replacement using the Edwards SAPIEN THV demonstrates excellent valve function and clinical outcomes at 3-year follow-up.

Premounted stents for branch pulmonary artery stenosis in children: A short term solution.

OBJECTIVE: Define outcomes of premounted stent implantation (PMS) for branch pulmonary artery stenosis (BPAS). BACKGROUND: PMS for BPAS in children raises concern of long term viability, with limited maximal expansion. METHODS: We reviewed our cardiac database over an 11-year period ending in 2013. Primary endpoint was need for surgical stent intervention (SSI). Other endpoints included acute results and repeat interventions (RI). RESULTS: 82 PMS were implanted in 60 children for BPAS. Median weight was 6.3 (25th -75th 4.6-9.8) kg. Median stent diameter was 6 (range 4-9) mm. Acutely, vessel diameter improved from 2.0 (25th -75th 1.6-3.4) to 5.0 (25th -75th 4.2-5.9) mm (p < 0.001), pressure gradient decreased from 41 (25th -75th 29-50) to 11 (25th -75th 7-18) mmHg (n = 47, p < 0.001), RV:Ao pressure ratio decreased from 100% (25th -75th 85-110%) to 59% (25th -75th 49-74%) (n = 40, p < 0.001). Freedom from SSI was 81% at 1 year and 35% at 5 years. Freedom from RI was 50% at 1 year and 14% at 5 years. 86% of PMS underwent SSI during a concomitant planned cardiac surgery. 45% patients had stent redilation, improving stent diameter from 4.6 (25th -75th 4.1-5.4) to 5.7 (25th -75th 4.9-7) mm (p < 0.001). 1 stent (3%) was able to be fractured longitudinally. CONCLUSIONS: PMS is an effective short term solution for BPAS in children. PMS is associated with expected early need for transcatheter reintervention to accommodate for growth, but also has high rates of SSI.

Transcatheter pulmonary valve replacement using the melody valve for treatment of dysfunctional surgical bioprostheses: A multicenter study.

BACKGROUND: Stented bioprosthetic valves (BPVs) are commonly used for surgical pulmonary valve (PV) replacement in postoperative congenital heart disease, but develop structural failure in a time-related fashion. The Melody transcatheter PV (TPV) (Medtronic, Minneapolis, Minn) has been used to treat BPV dysfunction, but there have been few studies in this population. METHODS: We performed a retrospective, multicenter study to evaluate Melody valve function in patients who underwent TPV replacement (TPVR) into a dysfunctional pulmonary BPV. RESULTS: One hundred patients who underwent TPVR at 10 centers between January 2010 and June 2015 were enrolled. The median patient age was 22 years (range, 5-79 years), and 32 patients were age <18 years. The underlying diagnosis was tetralogy of Fallot in 80 patients, and moderate or severe pulmonary regurgitation (PR) was present in 84%. The TPV was implanted into various types of BPVs, with a median size of 23 mm (range, 19-33 mm). At hospital discharge, PR was mild or less in all but 1 patient, and the mean Doppler right ventricular outflow tract (RVOT) gradient was reduced from a mean of 29.3 ± 12.0 mm Hg to 16.2 ± 6.9 mm Hg (median, 29 mm Hg to 16 mm Hg; P < .001). During follow-up (median, 12.4 months), no patients underwent reintervention on the TPV. Endocarditis was diagnosed in 1 patient who was managed medically without intervention. The mean RVOT gradient at the most recent follow-up was ≤35 mm Hg in all patients, and was similar to that at early postimplantation. PR was more than mild in only 1 patient. Hemodynamic outcomes did not differ between patients with small BPVs (≤23 mm) and those with large BPVs (≥25 mm). CONCLUSIONS: TPVR restores competence and relieves the obstruction of dysfunctional surgical BPVs, with excellent early results in both small and large BPVs, highlighting the potential for TPVR to extend the life of existing BPVs in adults and children. Collaboration between surgeons and cardiologists is important to determine the optimal lifetime management, combining surgical PV replacement and TPVR in this population.

Angiographic follow-up of infants and children undergoing percutaneous carotid artery interventions.

OBJECTIVE: The purpose of this study was to review the outcomes following the percutaneous carotid arterial (PCA) approach in infants and children with congenital heart disease. BACKGROUND: PCA access is becoming more commonly adopted following reports demonstrating it is a safe alternative to surgical carotid cutdown and even the femoral arterial route. However, follow-up outcomes after PCA remain unreported. METHODS: We reviewed all cases with PCA access and follow-up catheterizations which included carotid artery (CA) angiography between May 2012 until December 2016. We examined for evidence of CA stenosis at follow-up angiography and assessed any other CA complications associated with vascular access. RESULTS: There were 61 PCA catheterizations performed in 55 unique patients. Follow-up CA imaging with angiography was available in 43 patients (78%, 43/55). There was no vessel stenosis nor lumen irregularity in 28 (65%) patients. In 15 cases (35%), there was a mild degree of irregularity or narrowing by angiography (median 4.1%, range 2.3%-12.5%). Nine patients underwent repeat PCA catheterizations. Seven of these had no visible vascular stenosis on follow-up angiographic imaging, including a patient who was accessed three separate times from the CA. No statistically significant risk factors for developing mild CA stenosis were identified. CONCLUSIONS: PCA access for pediatric interventional catheterization appears to be safe with a very low rate of mild stenosis, and very few complications. Follow-up outcomes in our series are excellent, with a CA patency rate of 100%, even after multiple procedures. Mild CA stenosis was not associated with patient size or sheath introducer caliber. While the acute results from percutaneous CA catheterization have proven safe in recent literature, longer-term outcomes remain unreported. At our institution, the outcomes following percutaneous carotid access are associated with an excellent patency rate of 100%, even after multiple procedures on the same vessel. A low incidence of mild vessel stenosis can be appreciated on follow-up angiography.

Long or redundant leaflet complicating transcatheter mitral valve replacement: Case vignettes that advocate for removal or reduction of the anterior mitral leaflet.

Transcatheter mitral valve replacement (TMVR) procedures can be an alternative to surgical valve replacement for high surgical risk patients with bioprosthetic mitral valves, annuloplasty rings, or severe mitral annular calcification (MAC). TMVR can trigger acute left ventricular outflow tract (LVOT) obstruction from permanent displacement of the native anterior mitral leaflet toward the left ventricular septum, more often among patients undergoing valve-in-ring and valve-in-MAC procedures. Although acute LVOT obstruction is well described in the literature, there are important additional complications of TMVR related to the length and/or redundancy of the anterior mitral valve that have been recognized after mitral valve surgery and have not been previously reported in the setting of TMVR. These additional complications include acute mitral regurgitation secondary to prolapsing native leaflet through the TMVR, frozen TMVR leaflet secondary to overhanging native leaflet and late LVOT obstruction in the neo-LVOT secondary to long native leaflet. Preprocedural planning with imaging (echocardiography and computed tomography) and measurement of anterior mitral leaflet length is critical important in understanding the risk for these complications. As transcatheter mitral valve technology proliferates, interactions with the anterior mitral leaflet after TMVR may be more frequent than initially anticipated. We believe that there is no advantage to an intact anterior leaflet and advocate removal or reduction of the leaflet prior to TMVR. © 2017 Wiley Periodicals, Inc.

Intervention on Surgical Systemic-to-Pulmonary Artery Shunts: Carotid Versus Femoral Access.

OBJECTIVES: The purpose of this study was to compare results between the femoral arterial (FA) and carotid arterial (CA) approaches in catheter-based interventions on Blalock-Taussig shunts (BTS). BACKGROUND: Transcatheter intervention on BTS is often performed in shunt-dependent, hypoxemic infants. The approach to BTS intervention likely has an impact on timeliness and overall success. METHODS: The authors reviewed all cases of catheter intervention for BTS obstruction between 2012 and 2017 for their institution. They sought to compare procedural success rates and time, sheath time, time to arterial access, and time from access to stent implantation between FA and CA approaches. RESULTS: There were 42 BTS interventions between 34 patients. BTS intervention was more successful from the CA approach (p = 0.035). Among the FA cohort, BTS intervention was unsuccessful in 8 cases (25%), 5 of which were converted to CA with subsequent success. The CA cohort had lower procedure time (62 min vs. 104 min; p = 0.01) and anesthesia time (119 min vs. 151 min; p = 0.01). Additionally, CA access was associated with shorter time to arterial access (4.0 min vs. 9.3 min; p < 0.01), time to placement of the guidewire through the BTS (6.5 min vs. 13 min; p < 0.01), and time from the final sheath to BTS stent implantation (9 min vs. 20 min; p < 0.01). CONCLUSIONS: Operators should consider the route of access to the BTS deliberately. The authors' approach has been the carotid artery as an alternative access site-associated with greater procedural success, shorter procedural time, and shorter time to stent implantation.

Reintervention Is Associated With Improved Survival in Pediatric Patients With Pulmonary Vein Stenosis.

OBJECTIVES: The aim of this study was to evaluate survival following catheter intervention in pediatric patients with pulmonary vein stenosis (PVS). BACKGROUND: Despite aggressive surgical and catheter intervention on PVS in children, recurrence and progression of stenosis can lead to right heart failure and death. Clinicians continue to seek effective treatment options for PVS. METHODS: A single-center, retrospective study was performed including all patients <18 years of age who underwent catheter intervention (balloon angioplasty and bare-metal stent and drug-eluting stent insertion) on PVS. Endpoints included death, vein loss, and rate of reintervention. RESULTS: Thirty patients underwent intervention (balloon angioplasty, n = 9; bare-metal stent, n = 5; drug-eluting stent, n = 16) at a median age of 6.4 months (4.3 to 9.9 months). Median follow-up duration was 30.6 months (77 days to 10.5 years). Fourteen patients (47%) died at a median of 2.0 months (0.4 to 3.2 months) following intervention. There was no association between DES placement and survival (p = 0.067). Reintervention (catheter or surgical) was associated with improved survival (p = 0.001), with a 1-year survival rate of 84% compared with 25% for no reintervention. Vein loss occurred in 34 of 58 (59%) veins at a median of 3.3 months (1.0 to 5.0 months). One-year vein survival was higher with DES implantation (p = 0.031) and with reintervention (p < 0.001). CONCLUSIONS: DES implantation at first catheter intervention appears to be associated with improved vein survival but may not result in improved patient survival. However, reintervention appears to be associated with improved patient survival and vein patency, suggesting that despite mode of treatment, frequent surveillance is important in the care of these patients.

Multicenter Experience Evaluating Transcatheter Pulmonary Valve Replacement in Bovine Jugular Vein (Contegra) Right Ventricle to Pulmonary Artery Conduits.

BACKGROUND: Follow-up of transcatheter pulmonary valve replacement (TPVR) with the Melody valve has demonstrated good short-term and long-term outcomes, but there are no published studies focused on valve performance in the Contegra bovine jugular vein conduit. METHODS AND RESULTS: This is a retrospective, multicenter study of the short- and intermediate-term outcomes of Melody TPVR within the Contegra conduit in the right ventricle to pulmonary artery position. Data from 13 centers were included in the analysis. During the study period, 136 patients underwent 139 catheterizations for attempted Melody TPVR with a median follow-up of 3 years (1 day to 9.1 years). Of the 136 patients, 117 underwent successful Melody TPVR. Two patients underwent a second Melody TPVR. The majority of patients underwent placement of ≥1 stents before transcatheter pulmonary valve implantation. There was a significant reduction in peak conduit pressure gradient acutely after transcatheter pulmonary valve implantation (39 versus 10 mm Hg; P<0.001). At most recent follow-up, the maximum pulmonary valve gradient by echocardiogram remained significantly reduced relative to prevalve implant measurements (65.9 versus 27.3 mm Hg; P<0.001). The incidence of Melody transcatheter pulmonary valve stent fracture (3.4%) and infectious endocarditis (4.3%) were both low. Serious adverse events occurred in 3 patients. CONCLUSIONS: Melody TPVR in Contegra conduits is safe and effective and can be performed in a wide range of conduit sizes with preserved valve function and low incidence of stent fracture and endocarditis.

Intentional Percutaneous Laceration of the Anterior Mitral Leaflet to Prevent Outflow Obstruction During Transcatheter Mitral Valve Replacement: First-in-Human Experience.

OBJECTIVES: This study sought to use a new catheter technique to split the anterior mitral valve leaflet (AML) and prevent iatrogenic left ventricular outflow tract (LVOT) obstruction immediately before transcatheter mitral valve replacement (TMVR). BACKGROUND: LVOT obstruction is a life-threatening complication of TMVR, caused by septal displacement of the AML. METHODS: The procedure was used in patients with severe mitral valve disease and prohibitive surgical risk. Patients either had prior surgical mitral valve ring (n = 3) or band annuloplasty (n = 1) or mitral annular calcification with stenosis (n = 1). Iatrogenic LVOT obstruction or transcatheter heart valve dysfunction was predicted in all based on echocardiography and computed tomography. Transfemoral coronary guiding catheters directed an electrified guidewire across the center and base of the AML toward a snare in the left atrium. The externalized guidewire loop was then electrified to lacerate the AML along the centerline from base to tip, sparing chordae, immediately before transseptal TMVR. RESULTS: Five patients with prohibitive risk of LVOT obstruction or transcatheter heart valve dysfunction from TMVR successfully underwent LAMPOON, with longitudinal splitting of the A2 scallop of the AML, before valve implantation. Multiplane computed tomography modeling predicted hemodynamic collapse from TMVR assuming an intact AML. However, critical LVOT gradients were not seen following LAMPOON and TMVR. Doppler blood flow was seen across transcatheter heart valve struts that encroached the LVOT, because the AML was split. Transcatheter heart valve function was unimpeded. CONCLUSIONS: This novel catheter technique, which resembles surgical chord-sparing AML resection, may enable TMVR in patients with prohibitive risk of LVOT obstruction or transcatheter heart valve dysfunction.