Matthew J. Gillespie

Melody Valve Implant Within Failed Bioprosthetic Valves in the Pulmonary Position A Multicenter Experience

Background—Transcatheter pulmonary valve implantation using the Melody valve has emerged as an important therapy for the treatment of postoperative right ventricular outflow tract dysfunction. Melody-in-bioprosthetic valves (BPV) is currently considered an off-label indication. We review the combined experience with transcatheter pulmonary valve implantation within BPVs from 8 centers in the United States and discuss technical aspects of the Melody-in-BPV procedure. Methods and Results—A total of 104 patients underwent Melody-in-BPV in the pulmonary position at 8 US centers from April 2007 to January 2012. Ten different types of BPVs were intervened on, with Melody valve implantation at the intended site in all patients. Following Melody valve implant, the peak right ventricle-to-pulmonary artery gradient decreased from 38.7±16.3 to 10.9±6.7 mm Hg (P<0.001), and the right ventricular systolic pressure fell from 71.6±21.7 to 46.7±15.9 mm Hg (P<0.001). There was no serious procedural morbidity, and no deaths related to the catheterization or implant. At a median follow-up of 12 months (1–46 months), no patients had more than mild regurgitation, and 4 had a mean right ventricular outflow tract gradient ≥30 mm Hg. During follow-up, there were 2 stent fractures, 3 cases of endocarditis (2 managed with surgical explant), and 2 deaths that were unrelated to the Melody valve. Conclusions—Transcatheter pulmonary valve implantation using the Melody valve within BPVs can be accomplished with a high rate of success, low procedure-related morbidity and mortality, and excellent short-term results. The findings of this preliminary multicenter experience suggest that the Melody valve is an effective transcatheter treatment option for failed BPVs.

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.

Use of angiographic CT imaging in the cardiac catheterization laboratory for congenital heart disease.

OBJECTIVES This study sought to retrospectively evaluate our initial experience using angiographic computed tomography (ACT) in a pediatric cardiac catheterization laboratory. BACKGROUND ACT provides cross-sectional CT images from a rotational angiography run using a C-arm mounted flat-panel detector in the interventional suite. A 3-dimensional (3D) angiographic image can be created from the CT volume set and used in real time during the procedure. To our knowledge, its use has never previously been described for congenital heart disease. METHODS 3D reconstructions were created and we retrospectively reviewed cases during our first year of ACT use. Images obtained were independently evaluated to determine their diagnostic utility. Radiation dose reduction protocols were defined using phantom testing and radiation dose calculation. RESULTS ACT was used during 41 cardiac catheterizations in patients at a median age of 5.1 years (range: 0.4 to 58.8 years) for evaluation of: right ventricular outflow tract (RVOT)/central pulmonary arteries (PAs) in 20; cavopulmonary connection (CPC) in 11; pulmonary veins in 5; distal PAs in 4; and other locations in 5. Four subjects had 2 anatomic areas studied by ACT. The mean contrast volume for ACT was 1.2 ± 0.4 ml/kg. Diagnostic-quality imaging was obtained in 71% of cases: 13/20 RVOT/central PAs; 9/11 CPC; 4/5 pulmonary veins; 2/4 distal PAs; and 4/5 others. In 12 cases, ACT contributed to clinical outcomes beyond standard angiography. Radiation dose reduction protocols allowed ACT to be comparable in exposure to a standard biplane cineangiogram. CONCLUSIONS Diagnostic-quality imaging can be obtained using ACT in 71% of cases without a significant increase in contrast or radiation exposure. In certain cases, ACT provides additional anatomic detail and may aid complex catheter manipulations. Future work is needed to continue to define applications of this new technology.

Noninvasive quantification of systemic-to-pulmonary collateral flow: a major source of inefficiency in patients with superior cavopulmonary connections.

Background—Systemic-to-pulmonary collateral flow (SPCF) is common in single-ventricle patients with superior cavopulmonary connections (SCPC). Because no validated method to quantify that SPCF exists, neither its hemodynamic burden nor its clinical impact can be systematically evaluated. We hypothesize that (1) the difference in total ascending aortic (Ao) and caval flow (superior vena cava [SVC]+inferior vena cava [IVC]) and (2) the difference between pulmonary vein and pulmonary artery flow (PV−PA) provide 2 independent estimators of SPCF. Methods and Results—We measured Ao, SVC, IVC, right (RPA) and left (LPA) PA, and left (LPV) and right (RPV) PV flows in 17 patients with SCPC during routine cardiac MRI studies using through-plane phase-contrast velocity mapping. Two independent measures of SPCF were obtained: model 1, Ao−(SVC+IVC); and model 2, (LPV−LPA)+(RPV−RPA). Values were normalized to body surface area, Ao, and PV, and comparisons were made using linear regression and Bland-Altman analysis. SPCF ranged from 0.2 to 1.4 L/min for model 1 and 0.2 to 1.6 L/min for model 2, for an average indexed SPCF of 0.5 to 2.8 L/min/m2: 11% to 53% (mean, 37%) of Ao and 19% to 77% (mean, 54%) of PV. The mean difference between model 1 and model 2 was 0.01 L/min (P=0.40; 2-SD range, −0.45 to 0.47 L/min). Conclusions—We present a noninvasive method for SPCF quantification in patients with SCPC. It should provide an important clinical tool in treating these patients. Furthermore, we show that SPCF is a significant hemodynamic burden in many patients with bidirectional Glenn shunt physiology. Future investigations will allow objective study of the impact of collateral flow on outcome.Background— Systemic-to-pulmonary collateral flow (SPCF) is common in single-ventricle patients with superior cavopulmonary connections (SCPC). Because no validated method to quantify SPCF exists, neither its hemodynamic burden nor its clinical impact can be systematically evaluated. We hypothesize that (1) the difference in total ascending aortic (Ao) and caval flow (superior vena cava [SVC]+inferior vena cava [IVC]) and (2) the difference between pulmonary vein and pulmonary artery flow (PV−PA) provide 2 independent estimators of SPCF. Methods and Results— We measured Ao, SVC, IVC, right (RPA) and left (LPA) PA, and left (LPV) and right (RPV) PV flows in 17 patients with SCPC during routine cardiac MRI studies using through-plane phase-contrast velocity mapping. Two independent measures of SPCF were obtained: model 1, Ao−(SVC+IVC); and model 2, (LPV−LPA)+(RPV−RPA). Values were normalized to body surface area, Ao, and PV, and comparisons were made using linear regression and Bland-Altman analysis. SPCF ranged from 0.2 to 1.4 L/min for model 1 and 0.2 to 1.6 L/min for model 2, for an average indexed SPCF of 0.5 to 2.8 L/min/m2: 11% to 53% (mean, 37%) of Ao and 19% to 77% (mean, 54%) of PV. The mean difference between model 1 and model 2 was 0.01 L/min ( P =0.40; 2-SD range, −0.45 to 0.47 L/min). Conclusions— We present a noninvasive method for SPCF quantification in patients with SCPC. It should provide an important clinical tool in treating these patients. Furthermore, we show that SPCF is a significant hemodynamic burden in many patients with bidirectional Glenn shunt physiology. Future investigations will allow objective study of the impact of collateral flow on outcome. Received November 10, 2008; accepted July 7, 2009. # CLINICAL PERSPECTIVE {#article-title-2}

Percutaneous Lymphatic Embolization of Abnormal Pulmonary Lymphatic Flow as Treatment of Plastic Bronchitis in Patients With Congenital Heart Disease

Background— Plastic bronchitis is a potentially fatal disorder occurring in children with single-ventricle physiology, and other diseases, as well, such as asthma. In this study, we report findings of abnormal pulmonary lymphatic flow, demonstrated by MRI lymphatic imaging, in patients with plastic bronchitis and percutaneous lymphatic intervention as a treatment for these patients. Methods and Results— This is a retrospective case series of 18 patients with surgically corrected congenital heart disease and plastic bronchitis who presented for lymphatic imaging and intervention. Lymphatic imaging included heavy T2-weighted MRI and dynamic contrast-enhanced magnetic resonance lymphangiogram. All patients underwent bilateral intranodal lymphangiogram, and most patients underwent percutaneous lymphatic intervention. In 16 of 18 patients, MRI or lymphangiogram or both demonstrated retrograde lymphatic flow from the thoracic duct toward lung parenchyma. Intranodal lymphangiogram and thoracic duct catheterization was successful in all patients. Seventeen of 18 patients underwent either lymphatic embolization procedures or thoracic duct stenting with covered stents to exclude retrograde flow into the lungs. One of the 2 patients who did not have retrograde lymphatic flow did not undergo a lymphatic interventional procedure. A total of 15 of 17(88%) patients who underwent an intervention had significant symptomatic improvement at a median follow-up of 315 days (range, 45–770 days). The most common complication observed was nonspecific transient abdominal pain and transient hypotension. Conclusions— In this study, we demonstrated abnormal pulmonary lymphatic perfusion in most patients with plastic bronchitis. Interruption of the lymphatic flow resulted in significant improvement of symptoms in these patients and, in some cases, at least temporary resolution of cast formation.

Early systemic-to-pulmonary artery shunt intervention in neonates with congenital heart disease

OBJECTIVE To determine the incidence, risk factors, and outcomes after early, unplanned intervention on systemic-to-pulmonary artery shunts in neonates. METHODS We retrospectively studied all neonates undergoing systemic-to-pulmonary artery shunt placement at The Childrens Hospital of Philadelphia between September 1, 2002, and May 1, 2005. Patients requiring transcatheter or surgical systemic-to-pulmonary artery shunt intervention before discharge were compared with those not undergoing shunt intervention. RESULTS A total of 206 patients underwent shunt placement. Diagnoses included hypoplastic left heart syndrome (62.1%), pulmonary atresia (15%), tricuspid atresia (4.9%), tetralogy of Fallot (2.4%), and other lesions with obstruction to systemic (10.7%) or pulmonary blood flow (4.9%). Twenty-one interventions occurred in 20 patients (9.7%). Risk factors for intervention included heterotaxy syndrome (P = .04), congenital abnormality (P = .04), and a trend toward lower birthweight. In patients with a modified Blalock-Taussig shunt, similar risk factors were identified and the incidence of intervention decreased with increasing shunt size. In-hospital mortality was 30% (6/20) for the cases and 8.1% (15/186) for the nonintervention group (P = .02). Long-term survival was significantly lower in patients requiring intervention (P = .002). This group also had a higher incidence of infections (P < .001) and extracorporeal membrane oxygenation (P < .001), and longer hospital stay (P = .001). CONCLUSIONS In neonates undergoing systemic-to-pulmonary artery shunt placement, approximately 10% underwent shunt intervention before discharge. Some factors, such as low birthweight, shunt size, noncardiac congenital abnormalities, and heterotaxy syndrome, may help identify patients at risk. Patients undergoing intervention experienced increased morbidity and mortality.

Percutaneous Transvenous Melody® Valve-In-Ring Procedure For Mitral Valve Replacement

OBJECTIVES The purpose of this study was to demonstrate the feasibility of percutaneous transvenous mitral valve-in-ring (VIR) implantation using the Melody valve in an ovine model. BACKGROUND The recurrence of mitral regurgitation following surgical mitral valve (MV) repair in both adult and pediatric patients remains a significant clinical problem. Mitral annuloplasty rings are commonly used in MV repair procedures and may serve as secure landing zones for percutaneous valves. METHODS Five sheep underwent surgical MV annuloplasty (24 mm, n = 2; 26 mm, n = 2; 28 mm, n = 1). Animals underwent cardiac catheterization with VIR implantation via a transfemoral venous, transatrial septal approach 1 week following surgery. Hemodynamic, angiographic, and echocardiographic data were recorded before and after VIR. RESULTS VIR was technically successful and required <1 h of procedure time in all animals. Fluoroscopy demonstrated securely positioned Melody valves within the annuloplasty ring in all animals. Angiography revealed no significant MV regurgitation in 4 and moderate central MV regurgitation in the animal with the 28-mm annuloplasty. All animals demonstrated vigorous left ventricular function, no outflow tract obstruction, and no aortic valve insufficiency. CONCLUSIONS This study demonstrated the feasibility of a purely percutaneous approach to MV replacement in patients with preexisting annuloplasty rings. This novel approach may be of particular benefit to patients with failed repair of ischemic mitral regurgitation and in pediatric patients with complex structural heart disease.

Systemic-to-Pulmonary Collateral Flow, as Measured by Cardiac Magnetic Resonance Imaging, Is Associated With Acute Post-Fontan Clinical Outcomes

Background— Systemic-pulmonary collateral (SPC) flow occurs commonly in single ventricle patients after superior cavo-pulmonary connection, with unclear clinical significance. We sought to evaluate the association between SPC flow and acute post-Fontan clinical outcomes using a novel method of quantifying SPC flow by cardiac magnetic resonance (CMR) imaging. Methods and Results— All patients who had SPC flow quantified by CMR imaging before Fontan were retrospectively reviewed to assess for acute clinical outcomes after Fontan completion. Forty-four subjects were included who had Fontan completion between May 2008 and September 2010. SPC flow prior to Fontan measured 1.5±0.9 L/min/m2, accounting for 31±11% of total aortic flow and 44±15% of total pulmonary venous flow. There was a significant linear association between natural log-transformed duration of hospitalization and SPC flow as a proportion of total aortic (rho=0.31, P=0.04) and total pulmonary venous flow (rho=0.29, P=0.05). After adjustment for Fontan type and presence of a fenestration, absolute SPC flow was significantly associated with hospital duration ≥7 days (odds ratio [OR]=9.2, P=0.02) and chest tube duration ≥10 days (OR=22.7, P=0.009). Similar associations exist for SPC flow as a percentage of total aortic (OR=1.09, P=0.048 for hospitalization ≥7 days; OR=1.24, P=0.007 for chest tube duration ≥10 days) and total pulmonary venous flow (OR=1.07, P=0.048 for hospitalization ≥7 days; OR=1.18, P=0.006 for chest tube duration ≥10 days). Conclusions— Increasing SPC flow before Fontan, as measured by CMR imaging, is associated with increased duration of hospitalization and chest tube following Fontan completion.

X-Ray Magnetic Resonance Fusion to Internal Markers and Utility in Congenital Heart Disease Catheterization

Background—X-ray magnetic resonance fusion (XMRF) allows for use of 3D data during cardiac catheterization. However, to date, technical requirements have limited the use of this modality in clinical practice. We report on a new internal-marker XMRF method that we have developed and describe how we used XMRF during cardiac catheterization in congenital heart disease. Methods and Results—XMRF was performed in a phantom and in 23 patients presenting for cardiac catheterization who also needed cardiac MRI for clinical reasons. The registration process was performed in <5 minutes per patient, with minimal radiation (0.004 to 0.024 mSv) and without contrast. Registration error was calculated in a phantom and in 8 patients using the maximum distance between angiographic and 3D model boundaries. In the phantom, the measured error in the anteroposterior projection had a mean of 1.15 mm (standard deviation, 0.73). The measured error in patients had a median of 2.15 mm (interquartile range, 1.65 to 2.56 mm). Internal markers included bones, airway, image artifact, calcifications, and the heart and vessel borders. The MRI data were used for road mapping in 17 of 23 (74%) cases and camera angle selection in 11 of 23 (48%) cases. Conclusions—Internal marker–based registration can be performed quickly, with minimal radiation, without the need for contrast, and with clinically acceptable accuracy using commercially available software. We have also demonstrated several potential uses for XMRF in routine clinical practice. This modality has the potential to reduce radiation exposure and improve catheterization outcomes.

Determinants of Intensive Care Unit Length of Stay for Infants Undergoing Cardiac Surgery

OBJECTIVE The purpose of this study was to identify factors that influence postoperative intensive care unit length of stay (ICULOS) in infants less than 6 months of age undergoing congenital heart surgery. METHODS Records from a single institution, from January 2000 to December 2000, were reviewed. For analysis, surgical severity was characterized using an ordinal scoring system, the Aristotle Basic Complexity Score (ABCS; range 1-4). RESULTS Of 221 infants, 63 had elective surgery, that is, admission to the cardiac intensive care unit after surgery, and 158 had nonelective surgery with admission to the cardiac intensive care unit preoperatively. Elective vs. Nonelective groups differed: ABCS (median 2 vs. 3, P < .001), age at surgery (mean 110 + 10.5 vs. 27 + 3.7 days, P < .001), ICULOS (median 3.5 vs. 7 days, P < .000), and mortality (0% vs. 12.7%P < .0001). Step-wise multiple regression was performed using the natural log of ICULOS as the dependent variable. Factors associated with longer ICULOS for all 221 patients included: increasing ABCS, preoperative organ-system failure, total support time (= cardiopulmonary bypass time + deep hypothermic circulatory arrest time), total hours of postoperative ventilatory support, the need for postoperative cardiac catheterization, postoperative necrotizing enterocolitis, and postoperative nasogastric feeds. Higher preoperative weight and surgical repair vs. palliation were associated with a decrease in ICULOS. CONCLUSION In conclusion, preoperative organ dysfunction, need for nasogastric feeding, and total support time may offer measurable variables useful in predicting that infant at greatest risk for extended ICULOS.