Reducing Fluoroscopic Radiation Exposure During Endomyocardial Biopsy in Pediatric Transplant Recipients.

Endomyocardial biopsy (EMB) with fluoroscopy is used for rejection surveillance in pediatric heart transplantation. Lowering frame rate may reduce radiation, but decreases temporal resolution and image quality. We undertook a quality initiative reducing frame rate from 10 frames per second (FPS) to 5 FPS. To assess whether lowering frame rate can reduce radiation exposure without compromising safety, data on EMBs from 9/2009 to 4/2013 without angiography or intervention were reviewed. Effective dose was calculated from dose area product (DAP) and fluoroscopy time. Complications were reviewed. Independent t test compared pre- and post-data and a general linear model were used to control for confounders. Paired t test of most proximate data was used for pts with EMB before and after our change. Eighty-six patients had 543 EMB. After adjusting for weight, attending, and presence of a fellow, the lower FPS group had a 60.3% reduction in DAP (p < 0.0001) and 53.8% drop in effective dose (p < 0.0001). Fluoroscopy time did not differ. Twenty-eight pts had EMBs both before and after the FPS change. Pair-wise analysis of this group demonstrated a 33% reduction in DAP (p < 0.05) and 37% drop in effective dose (p < 0.01), without difference in fluoroscopy time. No patient had an increase in TR > 1 grade by ECHO. There were no deaths or perforations. Lowering the frame rate reduces radiation exposure by >50% without compromising safety. Efforts to further minimize radiation exposure of this vulnerable population should be considered.

Extracardiac Fontan fenestration using the SafeSept transseptal guidewire and snare-controlled diabolo-shaped covered-stent placement.

Transcatheter Fontan fenestration is a valuable option in situations of prolonged pleural drainage or low cardiac output in patients with failing Fontan circulation. This procedure relies on controlled baffle perforation without separation of the Fontan circuit from the pulmonary venous atrium, and placement of an accurately sized covered stent. We report a novel technique for transcatheter extracardiac Fontan fenestration using the SafeSept transseptal guidewire® and snare-controlled diabolo-shaped covered stent placement.

Growth of the atrial septum after Amplatzer device closure of atrial septal defects in young children.

BACKGROUND: Trans-catheter closure of atrial septal defects (ASD) with the Amplatzer Septal Occluder (ASO) device is safe and effective, but concern over erosions has increased. Devices are placed in growing children but septal growth after ASOs is ill-defined. Understanding the device relationship to cardiac structures as a child grows may help us understand erosions. OBJECTIVE: To define (1) how preprocedural septal measurements change after ASO and (2) the effect of somatic growth on these dimensions. METHODS: Data were collected retrospectively. Echocardiograms were reviewed and rims measured prior to ASO, immediately after ASO, and at follow-up. Demographic, procedural and device data were collected. RESULTS: Thirty-three patients were enrolled; mean age 5.2 ± 3.2 years with 4.0 ± 2.2 years follow-up. All septal measurements decreased after ASO. Thirty-one of 33 devices (94%) contacted the aortic root after ASO; all remained in contact at follow-up with only the IVC rim growing significantly over time. Change in BSA predicted an asymmetric septal growth with increases in superior (P = 0.01) and IVC (P = 0.005) rims and no increase in aortic or AVV rims. No episodes of erosion occurred. CONCLUSIONS: ASDs in young children are not central in the septum, but proximate to the aorta. After ASO, the device remains in close proximity to the aorta. With somatic growth, the septum grows asymmetrically, and device position relative to the aorta is constant. Our study was not powered to detect rare serious adverse events such as erosion, but aortic rims were consistently zero and yet no events occurred.

Standardizing radiation dose reporting in the pediatric cardiac catheterization laboratory-a multicenter study by the CCISC (Congenital Cardiovascular Interventional Study Consortium).

OBJECTIVES: We examine normalized air Kerma area product (PKA ) by body weight (PKA /BW) as a reference value of radiation dose and benchmark PKA /BW in pediatric laboratories using a multicenter registry database. BACKGROUND: Reduction of radiation dose is an important quality improvement task in pediatric cardiac catheterization laboratories. Physicians need to agree on a standard method of reporting radiation dose that would allow comparisons to be made between operators and institutions. METHODS: This was a multicenter observational study of radiation dose in pediatric laboratories. Patient demographic, procedural and radiation data including fluoroscopic time and PKA (µGy m(2) ) were analyzed. PKA /BW was obtained by indexing PKA to body weight. RESULTS: A total of 8,267 pediatric catheterization procedures (age <18 years) were included from 16 institutions. The procedures consisted of diagnostic (n = 2,827), transplant right ventricular (RV) biopsy (n = 1,172), and interventional catheterizations (n = 4268). PKA correlated with body weight better than with age and best correlated with weight-fluoroscopic time product. PKA /BW showed consistent values across pediatric ages. Interventional catheterizations had the highest PKA /BW (50th, 75th, and 90th percentiles: 72, 151, and 281 µGy m(2) /kg), followed by diagnostic (59, 105, and 175 µGy m(2) /kg) and transplant RV biopsy (27, 79, and 114 µGy m(2) /kg). CONCLUSION: PKA /BW appeared to be the most reliable standard to report radiation dose across all procedure types and patient age. We recommend PKA /BW to be used as the standard unit in documenting radiation usage in pediatric laboratories and can be used to evaluate strategies to lower radiation dosage in pediatric patients undergoing cardiac catheterizations. © 2014 Wiley Periodicals, Inc.

A Model for Assessment of Catheterization Risk in Adults With Congenital Heart Disease.

The purpose of this study was to define the risk for adults with congenital heart disease who underwent cardiac catheterization and to propose a precatheterization risk scoring system. Data were prospectively collected using a multicenter registry of the Congenital Cardiovascular Interventional Study Consortium. The occurrence of serious adverse events (SAE) was correlated with 12 predefined variables. Catheterization RISk in Adult patients (CRISA) score was derived using multivariate logistic regression with backward elimination model selection method. The CRISA score was compared with the American Society of Anesthesiology score and a consensus-derived, 20-point risk score based on their ability to predict SAE. From June 2008 to September 2017, 300 adjudicated SAE's occurred in 7317 catheterization procedures (overall SAE rate 4.1%) performed in adults over 18 years of age at 27 contributing centers. Nine of the 12 tested variables were ultimately included in the CRISA score. CRISA score positively correlated with risk of SAE, and was superior to American Society of Anesthesiology and the 20-point risk score in predicting SAE. Minimal (CRISA score 0 to 2), low (3 to 7), moderate (8 to 10) and high (≥11) risk categories were identified, corresponding to 0.5%, 3.2%, 7.9%, and 16.7% risk of SAE, respectfully. In conclusion, the CRISA score reliably predicts risk of SAE in adults with congenital heart disease who underwent cardiac catheterization and may be useful for preprocedural risk assessment.

Usefulness of troponin I as a marker of myocardial injury after pediatric cardiac catheterization.

Cardiac troponin I (cTnI) is a sensitive and specific marker of myocardial injury. The degree of myocardial injury associated with pediatric cardiac catheterization is unknown. We sought to investigate cTnI after pediatric cardiac catheterization, and to evaluate the degree of elevation observed with specific types of interventions. Seventy-three pediatric catheterizations were evaluated. Diagnostic procedures and interventions not expected to cause myocardial injury were assigned to group I, whereas interventional procedures expected to be associated with cardiac injury were assigned to group II. Group II procedures were further subdivided based on type of intervention. Serum samples were obtained before and after all procedures and analyzed for cTnI. Postprocedure cTnI levels were compared across groups and correlated with age and weight. Procedures in group II were associated with significantly higher cTnI levels than group I (median 2.65 ng/ml; interquartile range 0.9 to 4.9 ng/ml for group II vs 0.3; 0.3 to 1.6 ng/ml for group I, p <0.001). Within group II, cTnI was inversely correlated with age (p <0.05) and weight (p <0.05). Radiofrequency catheter ablation (RFA) caused higher cTnI levels than other types of interventions (median 3.7 ng/ml; 1.9 to 9.5 ng/ml for RFA vs 1.75; 0.7 to 4.9 ng/ml for non-RFA, p <0.05). Most pediatric interventional catheterization procedures are associated with myocardial injury, as evidenced by elevation of cTnI, with RFA causing higher levels than other interventions. Conversely, most diagnostic procedures are associated with no detectable myocardial injury. When compared with adult studies, pediatric patients seem to be at higher risk for myocardial injury from interventional cardiac catheterization.

A comparison of intravascular ultrasound with coronary angiography for evaluation of transplant coronary disease in pediatric heart transplant recipients.

BACKGROUND: The purpose of this study was to assess the sensitivity of coronary angiography versus intravascular ultrasound for detecting significant transplant coronary artery disease in children. We also examined associations between potential risk factors for transplant coronary artery disease and intravascular ultrasound findings, and evaluated the safety of intravascular ultrasound. METHODS: All pediatric heart transplant patients who had intravascular ultrasound following routine coronary angiography were included. Transplant coronary artery disease was quantified by assigning Stanford classes and calculating intimal indices for intravascular ultrasound images. These findings were compared with qualitative coronary angiography findings. Risk factors for transplant coronary artery disease, cardiac events and complications were recorded. RESULTS: Sixteen patients had 27 intravascular ultrasound procedures during the study period. All patients had evidence of transplant coronary artery disease at their latest intravascular ultrasound study. Of the patients whose most severely afflicted coronary artery underwent both imaging modalities at the latest study, 50% had significant transplant coronary artery disease (Stanford Class >/=II) by intravascular ultrasound and normal coronary angiography. A higher mean first-year biopsy score may be associated with significant transplant coronary artery disease by intravascular ultrasound, but a large number of patients will be required to determine this with statistical certainty. One major complication occurred early in the experience. CONCLUSIONS: In children, intravascular ultrasound is more sensitive for detecting significant transplant coronary artery disease than coronary angiography, but may add cost, time and potential morbidity to screening protocols. Prospective, multicenter studies are needed to best utilize intravascular ultrasound in this patient population.

Non-cameral coronary artery fistulae after pediatric cardiac transplantation: a multicenter study.

BACKGROUND: Cameral coronary artery fistulae (C-CAFs) are common after heart transplantation (HTx) and typically drain into the right ventricle. The development of CAFs to non-cameral structures after HTx has not been systematically investigated. We studied the incidence, anatomic distribution, and natural history of non-cameral CAFs (NC-CAFs) in a multicenter pediatric population. METHODS: Medical records from pediatric HTx patients at 2 centers from January 1, 1999, to August 31, 2009 were reviewed. A classification system for CAF size was developed, and serial angiograms were evaluated for CAF presence, size, and anatomy. Risk factors and outcomes were determined. RESULTS: Identified were 100 patients with a median age at HTx of 8.7 years. Median follow-up was 4.2 years. NC-CAFs occurred in 52 patients, C-CAFs in 20, with both types noted in 11. NC-CAFs originated from coronary arteries and drained predominantly into ipsilateral recipient pulmonary vasculature. Multiple NC-CAFs occurred in 19 patients (19%) for a total of 77 fistulae in 52 patients. Fistulae were classified as small (56%), moderate (36%), and large (8%). NC-CAFs were present at the first post-HTx angiogram in 95% of cases (median 1 year after HTx). Longer donor ischemic time was associated with the development (p = 0.043) and size (p = 0.05) of NC-CAFs. NC-CAFs were not associated with rejection, death, re-transplantation, or coronary revascularization, and none required intervention. CONCLUSIONS: Fistulae from donor coronary arteries to recipient pulmonary vasculature develop frequently and early after pediatric HTx. These correlate with graft ischemic time, but are not associated with early graft loss or death.

Endtidal carbon dioxide monitoring in children with congenital heart disease during sedation for cardiac catheterization by nonanesthesiologists.

BACKGROUND: This prospective observational study compared endtidal carbon dioxide (P(E)CO(2)) with blood gas carbon dioxide (PaCO(2)) values in children sedated by nonanesthesiologists for cardiac catheterization. METHODS: A nasal cannula designed to obtain gas sampling simultaneously from over the mouth and nares was taped into place after assuring a good waveform. Patients' cardiac lesions, site of blood gas sampling and P(E)CO(2)were recorded. RESULTS: Two hundred and one blood/P(E)CO(2) pairs were measured in 59 patients from 4 days to 18 years of age. Linear regression, Pearson correlation, and Bland-Altman analysis revealed a reasonable relationship (r = 0.493, P < 0.01, bivariate Pearson correlation) for all blood/expired CO(2) pairs even when the blood sample was obtained from an area of the circulation with shunting. There was no significant difference in the accuracy of the blood/P(E)CO(2) pairs between infants who weighed 15 kg. Thirteen children were diagnosed with partial or complete airway obstruction. CONCLUSIONS: Endtidal CO(2) measurement provides a reasonable reflection of blood CO(2) values if the expired gas-sampling catheter is taped in place after assuring a good waveform. The veracity of the data was the same throughout the patient size range. Expired CO(2) monitoring is useful for assessing the adequacy of respirations and the patency of the airway in children 3-89 kg.

Procedural results and acute complications in stenting native and recurrent coarctation of the aorta in patients over 4 years of age: a multi-institutional study.

BACKGROUND: We report a multi-institutional experience with intravascular stenting (IS) for treatment of coarctation of the aorta. METHODS AND RESULTS: Data was collected retrospectively by review of medical records from 17 institutions. The data was broken down to prior to 2002 and after 2002 for further analysis. A total of 565 procedures were performed with a median age of 15 years (mean=18.1 years). Successful reduction in the post stent gradient (<20 mm Hg) or increase in post stent coarctation to descending aorta (DAo) ratio of >0.8 was achieved in 97.9% of procedures. There was significant improvement (P<0.01) in pre versus post stent coarctation dimensions (7.4 mm+/-3.0 mm vs. 14.3+/-3.2 mm), systolic gradient (31.6 mm Hg+/-16.0 mm Hg vs. 2.7 mm Hg+/-4.2 mm Hg) and ratio of the coarctation segment to the DAo (0.43+/-0.17 vs. 0.85+/-0.15). Acute complications were encountered in 81/565 (14.3%) procedures. There were two procedure related deaths. Aortic wall complications included: aneurysm formation (n=6), intimal tears (n=8), and dissections (n=9). The risk of aortic dissection increased significantly in patients over the age of 40 years. Technical complications included stent migration (n=28), and balloon rupture (n=13). Peripheral vascular complications included cerebral vascular accidents (CVA) (n=4), peripheral emboli (n=1), and significant access arterial injury (n=13). Older age was significantly associated with occurrence of CVAs. A significant decrease in the technical complication rate from 16.3% to 6.1% (P<0.001) was observed in procedures performed after January 2002. CONCLUSIONS: Stent placement for coarctation of aorta is an effective treatment option, though it remains a technically challenging procedure. Technical and aortic complications have decreased over the past 3 years due to, in part, improvement in balloon and stent design. Improvement in our ability to assess aortic wall compliance is essential prior to placement of ISs in older patients with coarctation of the aorta.

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.

Standardizing Radiation Dose Reporting in thePediatric Cardiac Catheterization Laboratory—AMulticenter Study by the CCISC (CongenitalCardiovascular Interventional Study Consortium)

We examine normalized air Kerma area product (PKA) by body weight(PKA/BW) as a reference value of radiation dose and benchmark PKA/BW in pediatriclaboratories using a multicenter registry database. Background: Reduction of radiationdose is an important quality improvement task in pediatric cardiac catheterizationlaboratories. Physicians need to agree on a standard method of reportingradiation dose that would allow comparisons to be made between operators andinstitutions. Methods: This was a multicenter observational study of radiation dosein pediatric laboratories. Patient demographic, procedural and radiation data includingfluoroscopic time and PKA (mGy m2) were analyzed. PKA/BW was obtained byindexing PKA to body weight. Results: A total of 8,267 pediatric catheterization procedures(age <18 years) were included from 16 institutions. The procedures consistedof diagnostic (n52,827), transplant right ventricular (RV) biopsy (n51,172),and interventional catheterizations (n54268). PKA correlated with body weight betterthan with age and best correlated with weight–fluoroscopic time product. PKA/BWshowed consistent values across pediatric ages. Interventional catheterizations hadthe highest PKA/BW (50th, 75th, and 90th percentiles: 72, 151, and 281 lGy m2/kg),followed by diagnostic (59, 105, and 175 lGy m2/kg) and transplant RV biopsy (27,79, and 114 lGy m2/kg). Conclusion: PKA/BW appeared to be the most reliablestandard to report radiation dose across all procedure types and patient age. We recommend PKA/BW to be used as the standard unit in documenting radiationusage in pediatric laboratories and can be used to evaluate strategies to lower radiationdosage in pediatric patients undergoing cardiac catheterizations.