This trial will evaluate the efficacy and safety of the modified Blalock-Taussig shunt (MBTS) compared to the right ventricle to pulmonary artery (RV-to-PA) shunt; compare the effect of the MBTS to that of the RV-to-PA shunt on the incidence of death or cardiac transplantation at 12 months post randomization; and compare the effect of the two shunts on intensive care unit (ICU) morbidity, unintended cardiovascular interventional procedures, right ventricular function, tricuspid valve regurgitation, pulmonary artery growth, and neurodevelopmental outcome.
BACKGROUND: Hypoplastic left heart syndrome (HLHS) and related single right ventricle anomalies are the highest risk congenital cardiovascular malformations. Surgical repair begins with the Norwood procedure during the newborn period, a stage II procedure at 4 to 6 months of age, and Fontan procedure at 18 to 36 months. The Norwood procedure remains one of the highest risk procedures in congenital heart surgery. A few small nonrandomized studies of a novel approach to the Norwood procedure have reported improved outcomes. This new approach uses a RV-to-PA shunt to provide pulmonary blood flow rather than the standard MBTS. This multi-center, randomized clinical trial will evaluate early and intermediate-term outcomes for patients undergoing a Norwood procedure with either the RV-to-PA shunt or the MBTS. This study has been approved by the Institutional Review/Research Ethics Boards of all participating clinical centers: Hospital for Sick Children, Toronto, Canada Children's Hospital Boston, Boston, MA Columbia College of Physicians and Surgeons, New York, NY Children's Hospital of Philadelphia, Philadelphia, PA Duke University Medical Center, Durham, NC Brody School of Medicine at East Carolina University, Greenville, NC Wake Forest Baptist Medical Center, Winston Salem, NC Medical University of South Carolina, Charleston, SC Children's Hospital of Wisconsin, Milwaukee, WI University of Michigan, Ann Arbor, MI Cincinnati Children's Hospital Medical Center, Cincinnati, OH Children's Hospital of Los Angeles, Los Angeles, CA Egleston Children's Hospital, Emory University, Atlanta, GA Congenital Heart Institute of Florida, University of South Florida, St. Petersburg, FL Alfred I. duPont Hospital for Children, Wilmington, DE DESIGN NARRATIVE: This is a prospective, randomized clinical trial of the RV-to-PA shunt versus MBTS in patients undergoing a Norwood procedure.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
555
Performed at stage I palliative surgery for babies born with HLHS
Performed at stage I palliative surgery for babies born with HLHS
Children's Hospital of Los Angeles
Los Angeles, California, United States
Alfred I. duPont Hospital for Children
Wilmington, Delaware, United States
Cardiac Surgical Associates
St. Petersburg, Florida, United States
Children's Healthcare of Atlanta at Egleston
Atlanta, Georgia, United States
Children's Hospital Boston
Boston, Massachusetts, United States
University of Michigan Health System/Mott Hospital
Ann Arbor, Michigan, United States
Columbia College of Physicians and Surgeons
New York, New York, United States
Duke University Medical Center
Durham, North Carolina, United States
Cincinnati Children's Hospital Medical Center
Cincinnati, Ohio, United States
Children's Hospital of Philadelphia
Philadelphia, Pennsylvania, United States
...and 3 more locations
Proportion of Patients Who Died or Received a Heart Transplant
The primary outcome was the proportion of patients who died or had cardiac transplantation 12 months after randomization.
Time frame: Measured at 12 months
Proportion of Deaths or Heart Transplants Over Time From Randomization to the End of the Trial
This secondary outcome was the proportion of deaths or cardiac transplantation over time from randomization to the end of the trial.
Time frame: From Randomization to the End of the Trial, an average of 32 months
Echocardiographic Measures of Heart Size and Function: Right Ventricle (RV) End-diastolic Volume Indexed to Body Surface Area (BSA)
Right ventricular end-diastolic volume indexed to BSA\^1.3. Echocardiograms were performed at time points relative to the two palliative surgeries (post-Norwood and pre-Stage II) as well as at the specific time point of 14 months of age.
Time frame: Measured post-Norwood, an average of 17 days post-Norwood
Echocardiographic Measures of Heart Size and Function: RV End-diastolic Volume Indexed to BSA
Right ventricular end-diastolic volume indexed to BSA\^1.3. Echocardiograms were performed at time points relative to the two palliative surgeries (post-Norwood and pre-Stage II) as well as at the specific time point of 14 months of age.
Time frame: Measured pre-stage II surgery, an average of 15 days pre-stage II surgery
Echocardiographic Measures of Heart Size and Function: RV End-diastolic Volume Indexed to BSA
Right ventricular end-diastolic volume indexed to BSA\^1.3. Echocardiograms were performed at time points relative to the two palliative surgeries (post-Norwood and pre-Stage II) as well as at the specific time point of 14 months of age.
Time frame: Measured at 14 months of age
Echocardiographic Measures of Heart Size and Function: RV End-systolic Volume Indexed to BSA
Right ventricular end-systolic volume indexed to BSA. Echocardiograms were performed at time points relative to the two palliative surgeries (post-Norwood and pre-Stage II) as well as at the specific time point of 14 months of age.
Time frame: Measured post-Norwood, an average of 17 days post-Norwood
Echocardiographic Measures of Heart Size and Function: RV End-systolic Volume Indexed to BSA
Right ventricular end-systolic volume indexed to BSA\^1.3. Echocardiograms were performed at time points relative to the two palliative surgeries (post-Norwood and pre-Stage II) as well as at the specific time point of 14 months of age.
Time frame: Measured pre-stage II surgery, an average of 15 days pre-stage II surgery
Echocardiographic Measures of Heart Size and Function: RV End-systolic Volume Indexed to BSA
Right ventricular end-systolic volume indexed to BSA\^1.3. Echocardiograms were performed at time points relative to the two palliative surgeries (post-Norwood and pre-Stage II) as well as at the specific time point of 14 months of age.
Time frame: Measured at 14 months of age
Echocardiographic Measures of Heart Size and Function: RV Ejection Fraction
Right ventricular ejection fraction: 100 x (RV end-diastolic volume - RV end-systolic volume)/RV end-diastolic volume. Echocardiograms were performed at time points relative to the two palliative surgeries (post-Norwood and pre-Stage II) as well as at the specific time point of 14 months of age.
Time frame: Measured post-Norwood, an average of 17 days post-Norwood
Echocardiographic Measures of Heart Size and Function: RV Ejection Fraction
Right ventricular ejection fraction: 100 x (RV end-diastolic volume - RV end-systolic volume)/RV end-diastolic volume. Echocardiograms were performed at time points relative to the two palliative surgeries (post-Norwood and pre-Stage II) as well as at the specific time point of 14 months of age.
Time frame: Measured pre-stage II surgery, an average of 15 days pre-stage II surgery
Echocardiographic Measures of Heart Size and Function: RV Ejection Fraction
Right ventricular ejection fraction: 100 x (RV end-diastolic volume - RV end-systolic volume)/RV end-diastolic volume. Echocardiograms were performed at time points relative to the two palliative surgeries (post-Norwood and pre-Stage II) as well as at the specific time point of 14 months of age.
Time frame: Measured at 14 months of age
Angiographic Findings: Left Pulmonary Artery Size
Diameter of distal left pulmonary artery. Angiograms were performed at the time points relative to the second palliative surgery (pre-Stage II).
Time frame: Measured pre-stage II surgery, on average 26 days prior to stage II palliation
Angiographic Findings: Right Pulmonary Artery Size
Diameter of distal right pulmonary artery. Angiograms were performed at the time points relative to the second palliative surgery (pre-Stage II).
Time frame: Measured pre-stage II surgery, on average 26 days prior to stage II palliation
Unintended Cardiovascular Interventional Procedures
Unintended cardiovascular procedures included balloon dilation of the shunt or branch pulmonary arteries, stent placement in the shunt or branch pulmonary arteries, shunt revision, crossover between MBTS and RVPAS shunt, balloon dilation, stent placement or surgical revisions of the neo-aorta, and pulmonary artery reconstructions, other than those undertaken as a standard component of the stage II procedure. The number of cardiovascular procedures was analyzed; trial participants may have had more than one unintended cardiovascular. procedure.
Time frame: From Randomization to 12 months
Complications: Total Number Experienced During Norwood Hospitalization
Complications, reported as 'Other Adverse Events' in the safety section, are those adverse events that were not considered serious. Many normal peri-operative occurrences meet the standard criteria of an adverse event; therefore, for this trial a serious adverse event was (a) death, (b) acute shunt failure requiring intervention, (c) cardiac arrest requiring CPR and medications, (d) cardiopulmonary insufficiency requiring ECMO, (e) cardiovascular re-operation (unplanned), (f) necrotizing enterocolitis requiring laparotomy, and (g) any event considered by the study investigator as serious.
Time frame: Norwood Hospitalization, an average of 36 days
Complications: Total Number Experienced From Norwood Discharge to Stage II Discharge
Complications, reported as 'Other Adverse Events' in the safety section, are those adverse events that were not considered serious. Many normal peri-operative occurrences meet the standard criteria of an adverse event; therefore, for this trial a serious adverse event was (a) death, (b) acute shunt failure requiring intervention, (c) cardiac arrest requiring CPR and medications, (d) cardiopulmonary insufficiency requiring ECMO, (e) cardiovascular re-operation (unplanned), (f) necrotizing enterocolitis requiring laparotomy, and (g) any event considered by the study investigator as serious.
Time frame: From Norwood Discharge to Stage II discharge, an average of 4.2 months
Complications: Total Number Experienced From Stage II Discharge to 14 Months of Age
Complications, reported as 'Other Adverse Events' in the safety section, are those adverse events that were not considered serious. Many normal peri-operative occurrences meet the standard criteria of an adverse event; therefore, for this trial a serious adverse event was (a) death, (b) acute shunt failure requiring intervention, (c) cardiac arrest requiring CPR and medications, (d) cardiopulmonary insufficiency requiring ECMO, (e) cardiovascular re-operation (unplanned), (f) necrotizing enterocolitis requiring laparotomy, and (g) any event considered by the study investigator as serious.
Time frame: From Stage II Discharge to 14 Months of Age, an average of 8.9 months
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