Gabriel Amir

The metabolic effects of fresh versus old stored blood in the priming of cardiopulmonary bypass solution for pediatric patients

OBJECTIVESnPediatric cardiopulmonary bypass involves the creation of a large obligatory priming reservoir. Packed red blood cells are an essential part of the cardiopulmonary bypass priming solution in children. The storage media in packed red blood cells might cause significant acid-base, glucose, and electrolyte imbalances, which have been associated with severe complications. The purpose of the present study was to evaluate the metabolic effects of fresh (< or =5 days) versus old (>5 days) stored packed red blood cells added to the priming solutions of pediatric patients undergoing cardiac surgery.nnnMETHODSnBlood samples were drawn from cardiopulmonary bypass priming of 30 consecutive pediatric patients undergoing cardiac surgery. Patients were divided into 2 groups. Fresh (< or =5 days old) stored packed red blood cells were added to the priming solution in group 1, and old (>5 days old) stored packed red blood cells were added to the priming solution in group 2. In each group blood samples were drawn from the packed red blood cells on arrival to the operating room and from the priming solution immediately after packed red blood cells were added and after 20 minutes of prime circulation. Samples were also collected at the beginning of cardiopulmonary bypass and after 30 minutes. The last sample was collected on arrival to the pediatric intensive care unit. The levels of potassium, glucose, and lactate and the acid-base balance were analyzed in each sample.nnnRESULTSnThere was a linear increase in potassium levels in packed red blood cell samples with increasing packed red blood cell age, ranging from 5.4 to 18.4 mEq/L. Significant differences in the concentrations of potassium, glucose, and lactate and the acid-base balance were found when comparing old and fresh packed red blood cells in samples taken during the packed red blood cell and early prime time. Those differences resolved after 20 minutes of reconstitution of the priming solution. The age of the packed red blood cells had no effect on the samples taken during bypass and those taken in the pediatric intensive care unit.nnnCONCLUSIONnThe significantly higher concentration of potassium and lactate and lower pH in old stored packed red blood cells has a minimal effect on the final constitution of priming solution before and during cardiopulmonary bypass in children undergoing corrective cardiac surgery.

Predictors of early and overall outcome in coronary artery bypass without cardiopulmonary bypass.

OBJECTIVEnCardiopulmonary bypass in coronary artery bypass graft operations may adversely affect the outcome especially in high-risk patients. The purpose of this study is to evaluate results of coronary artery bypass performed without cardiopulmonary bypass, in a relatively high-risk cohort, and to identify predictors of unfavorable outcome.nnnMETHODnThree hundred and thirteen (313) patients, 246 (79%) of whom had high-risk conditions, who have a coronary anatomy suitable for coronary artery bypass surgery without cardiopulmonary bypass, underwent this procedure between December 1991 and July 1995. Mean number of grafts/patient was 1.8 (1-5), and only 71 patients (23%) received a graft to the circumflex coronary system.nnnRESULTSnEarly unfavorable outcome events included operative mortality (12 patients, 3.8%), nonfatal perioperative myocardial infarction (eight patients, 2.6%), emergency reoperation (three patients, 0.9%), sternal infection (five patients, 1.6%), and nonfatal stroke (two patients, 0.6%). Multivariate analysis revealed angina pectoris class IV (odds ratio 5.4) and age > or = 70 years (odds ratio 5.0) as independent predictors of early mortality. Preoperative risk factors such as repeat coronary artery bypass grafting (50 patients, 16%), ejection fraction < or = 0.35 (85 patients, 27%), acute myocardial infarction (86 patients, 28%), cardiogenic shock (ten patients, 3.2%), chronic renal failure (25 patients, 8%), chronic obstructive pulmonary disease (20 patients, 6%), and peripheral vascular disease (51 patients, 16%) did not increase early mortality. During 33 months of follow-up (range 1-57 months), there were 42 deaths, at least 16 cardiac-related (one and four years actuarial survival of 90% and 76% respectively), and 39 patients (12.5%) in whom angina returned. Calcified aorta (odds ratio 2.6) and old myocardial infarction (odds ratio 1.8) were independent predictors of overall unfavorable events.nnnCONCLUSIONSnCoronary artery bypass grafting without cardiopulmonary bypass can be performed with relatively low operative mortality in certain high-risk subgroups of patients; however, an increased risk of graft occlusion is a potential disadvantage. This procedure should therefore be considered only for patients with suitable coronary anatomy, in whom cardiopulmonary bypass poses a high risk. Although the risk of stroke is relatively low, the procedure is still hazardous for patients aged 70 years and over.

Preservation of myocyte structure and mitochondrial integrity in subzero cryopreservation of mammalian hearts for transplantation using antifreeze proteins--an electron microscopy study.

OBJECTIVEnFreeze tolerant fish and insects in nature are able to survive subzero temperatures by noncolligatively lowering the freezing temperature of their body fluids using a family of thermal hysteresis proteins (antifreeze proteins, AFPs) specific for each species. Past efforts to cryopreserve mammalian hearts using these proteins were unsuccessful. We report the first successful subzero cryopreservation of rat hearts using fish derived antifreeze proteins with preservation of myocyte structure.nnnMETHODSnHeterotopic heart transplantations were performed in isoimmunic Sprague Dawley rats. Donors hearts were arrested using University of Wisconsin (UW) solution and preserved in UW solution containing AFP I (six experiments) or AFP III (six experiments) at concentrations of 15-20 mg/cc for 2-6 h at subzero temperatures ranging from -1.1 to -1.3 degrees C. Four control experiments were performed by preserving harvested hearts in UW solution alone at -1.3 degrees C for 6 h. In all experiments ice was added in the solution for crystallization. Heterotopic transplantations were performed in the abdomen of the recipient rats. Viability was visually assessed and graded on a scale of 1 (poor contraction) to 6 (excellent contraction). The hearts were then fixed in vivo and processed for electron microscopy study.nnnRESULTSnAll hearts preserved at subzero temperatures using AFP I or AFP III survived displaying viability scores of 4-6 1 h after transplantation. Three of the four control hearts that were preserved at -1.3 degrees C without the protective effect of AFP froze and died upon reperfusion. Electron microscopy study of hearts preserved with AFP demonstrated preservation of myocyte structure and mitochondrial integrity.nnnCONCLUSIONnSubzero cryopreservation of mammalian hearts for transplantation using AFP I or AFP III is feasible with preservation of myocyte structure and mitochondrial integrity.

Covered Cheatham-Platinum stents for serial dilatation of severe native aortic coarctation.

Objectives: To report on the early results of treatment of native coarctation of the aorta by implantation and serial dilations of covered stents. Background: Transcatheter dilation of native coarctation of the aorta carries a risk of aneurysm or rupture. Covered stent implantation requires a large delivery system with the risk of vascular damage. Methods: Covered stents on balloons of diameter sufficient to anchor the stent in the coarctation were implanted using the smallest delivery system possible. Dilation with larger diameter balloons was performed until the pressure gradient was <20 mm Hg and the stent was opposed to the aortic wall. Results: Twenty‐two patients with native coarctation underwent stent implantation. Coarctation diameter increased from 3.6 ± 1.9 to 12.6 ± 1.9 mm (P < 0.001). Peak pressure gradient decreased from 29.4 ± 8.5 to 6.7 ± 5.7 mm Hg (P < 0.001). Nine patients underwent further dilation on average 5 months later. Residual pressure gradient decreased from 12.3 ± 5.8 to 2.1 ± 2.9 mm Hg (P = 0.002). The stent achieved the diameter of the transverse arch in all cases. Complications included a small tear at further dilation treated with a second stent and a femoral pseudoaneurysm. At short‐term follow‐up of 18.5 months all patients are alive and well with no evidence of recoarctation or aneurysm. Conclusions: These initial results show that serial dilation of covered Cheatham‐Platinum stents is feasible, safe, and an effective percutaneous method for the treatment of native coarctation of the aorta. However, long‐term follow up is required.

Evaluation of a Peritoneal-Generated Cardiac Patch in a Rat Model of Heterotopic Heart Transplantation

Tissue engineering holds the promise of providing new solutions for heart transplant shortages and pediatric heart transplantation. The aim of this study was to evaluate the ability of a peritoneal-generated, tissue-engineered cardiac patch to replace damaged myocardium in a heterotopic heart transplant model. Fetal cardiac cells (1 × 106/scaffold) from syngeneic Lewis rats were seeded into highly porous alginate scaffolds. The cell constructs were cultured in vitro for 4 days and then they were implanted into the rat peritoneal cavity for 1 week. During this time the peritoneal-implanted patches were vascularized and populated with myofibroblasts. They were harvested and their performance in an infrarenal heterotopic abdominal heart transplantation model was examined (n = 15). After transplantation and before reperfusion of the donor heart, a 5-mm left (n = 6) or right (n = 9) ventriculotomy was performed and the patch was sutured onto the donor heart to repair the defect. Echocardiographical studies carried out 1–2 weeks after transplantation showed normal LV function in seven of the eight hearts studied. After 1 month, visual examination of the grafted patch revealed no aneurysmal dilatation. Microscopic examination revealed, in most of the cardiac patches, a complete disappearance of the scaffold and its replacement by a consistent tissue composed of myofibroblasts embedded in collagen bundles. The cardiac patch was enriched with a relatively large number of infiltrating blood vessels. In conclusion, cardiac patches generated in the peritoneum were developed into consistent tissue patches with properties to seal and correct myocardial defects. Our study also offers a viable rat model for screening and evaluating new concepts in cardiac reconstruction and engineering.

Prenatal Diagnosis and Outcome of Right Aortic Arch without Significant Intracardiac Anomaly

BACKGROUNDnRight aortic arch (RAA) is usually associated with the presence of a significant congenital heart disease, usually a conotruncal defect, which determines the postnatal outcome. In the absence of such cardiac defects, the significance of RAA has not been determined. The aims of this study were to evaluate the significance of recognizing RAA in fetuses with normal or near normal intracardiac anatomy and to determine which associations may be present.nnnMETHODSnA retrospective study was completed of all fetuses diagnosed with RAA with normal or near normal intracardiac anatomy between 1999 and 2011. The aim was to evaluate the presence of RAA with complete ultrasonic evaluation using two-dimensional imaging complemented by the Doppler color flow technique, paying particular attention to the three-vessel and tracheal view. We compared the prenatal findings with the postnatal outcomes and management of this cohort of fetuses.nnnRESULTSnAmong 16,450 fetal echocardiograms, 58 fetuses (0.35%) were diagnosed with RAA with normal or near normal intracardiac anatomy. Gestational age at diagnosis ranged from 19 to 34 weeks (mean, 23 weeks). Isolated RAAs were found in 50 fetuses, and double aortic arches (DAAs) were recognized in eight other cases. The postnatal cohort consisted of 44 newborns with RAAs and eight with DAAs (two were lost to follow-up, and four pregnancies were terminated). Postnatal echocardiography confirmed the prenatal diagnosis of RAA in 41 of 45 children, and four were found to have DAAs. Three of seven fetuses diagnosed prenatally as having DAAs were found to have only RAAs. Fourteen fetuses underwent karyotyping; two had 22q11 deletion and two had 47xxy. Eleven infants (21%) had respiratory symptoms, eight with DAAs, one with RAA, mirror-image head and neck vessels, and two with RAAs and aberrant left subclavian arteries. Surgery was indicated in all symptomatic patients except one, whose symptoms resolved. One asymptomatic patient underwent operation for significant compression of the trachea.nnnCONCLUSIONSnRAA on fetal ultrasonography may indicate vascular and chromosomal abnormalities that may complicate postnatal management. When RAA is identified, fetal karyotype analysis (including the integrity of chromosome 22) is warranted. RAA may herald an occult DAA and may be a clue to a tight vascular ring. Hence, it seems essential to conduct a careful postnatal evaluation of fetuses with RAAs on prenatal ultrasound.

Favorable outcome of pediatric fulminant myocarditis supported by extracorporeal membranous oxygenation.

Myocarditis among pediatric patients varies in severity from mild disease to a fulminant course with overwhelming refractory shock and a high risk of death. Because the disease is potentially reversible, it is reasonable to deploy extracorporeal membranous oxygenation (ECMO) to bridge patients until recovery or transplantation. This study aimed to review the course and outcome of children with acute fulminant myocarditis diagnosed by clinical and echocardiographic data only who were managed by ECMO because of refractory circulatory collapse. A chart review of a single center identified 12 children hospitalized over an 8-year period who met the study criteria. Data were collected on demographics, diagnosis, disease course, and outcome. The patients ranged in age from 20xa0days to 8xa0years (25.5xa0±xa029.6xa0months). Echocardiography showed a severe global biventricular decrease in myocardial function, with a shortening fraction of 12% or less. Ten children (83.3%) were weaned off extracorporeal support after 100–408xa0h (mean, 209.9xa0±xa082.4xa0h) and discharged home. Two patients died: one due to multiorgan failure and one due to sustained refractory heart failure. During a long-term follow-up period, all survivors showed normal function in daily activities and normal myocardial function. The study showed that ECMO can be safely and successfully used for children with acute fulminant myocarditis diagnosed solely on clinical and radiographic grounds who need mechanical support. These patients usually have a favorable outcome, regaining normal or near normal heart function without a need for heart transplantation.

Computer-generated real-time digital holography: first time use in clinical medical imaging

AIMSnAssessment of the feasibility of creating real-time interactive 3D digital holograms in a standard catheterization laboratory. 3D medical images are typically displayed and interacted with on 2D screens limiting their usefulness. A digital computer-generated real-time holographic display of patients 3D data could provide a spatially accurate image with all the depth cues and afford interaction within the image.nnnMETHODS AND RESULTSnWe performed a feasibility study of creating real-time interactive 3D digital holograms with a purpose-built prototype using intraprocedural data from 3D rotational angiography and live 3D transesophageal echocardiography. The primary objective was to demonstrate that all the anatomical landmarks identified on standard imaging can be similarly identified using dynamic and static holographic images. The secondary objective was to demonstrate the usability of interactions with the image. Parameters were assessed by a rating scale. Eight patients were enrolled of whom five underwent transcatheter ASD closure using 3DTEE and three patients were evaluated by 3D rotational angiography. In all cases dynamic real-time and static 3D holograms were created in standard cath lab conditions. Four individual observers identified all anatomical landmarks on the holographic display independently from the 2D display. Interactions with the hologram including marking, cropping and rotation were performed. There were no adverse events.nnnCONCLUSIONSnThis study demonstrates, for the first time, the feasibility of generating high quality, clinically relevant, 3D real-time colour dynamic holograms in a standard clinical setting with real patient volumetric data. The impact of computer-generated holography needs to be evaluated in controlled clinical trials.

Staged Transcatheter Treatment of Portal Hypoplasia and Congenital Portosystemic Shunts in Children

PurposeCongenital portosystemic shunts (CPSS) with portal venous hypoplasia cause hyperammonemia. Acute shunt closure results in portal hypertension. A transcatheter method of staged shunt reduction to afford growth of portal vessels followed by shunt closure is reported.MethodsPressure measurements and angiography in the CPSS or superior mesenteric artery (SMA) during temporary occlusion of the shunt were performed. If vessels were diminutive and the pressure was above 18xa0mmHg, a staged approach was performed, which included implantation of a tailored reducing stent to reduce shunt diameter by ~50xa0%. Recatheterization was performed approximately 3xa0months later. If the portal pressure was below 18xa0mmHg and vessels had developed, the shunt was closed with a device.ResultsSix patients (5 boys, 1 girl) with a median age of 3.3 (range 0.5–13) years had CPSS portal venous hypoplasia and hyperammonemia. Five patients underwent staged closure. One patient tolerated acute closure. One patient required surgical shunt banding because a reducing stent could not be positioned. At median follow-up of 3.8 (range 2.2–8.4) years, a total of 21 procedures (20 transcatheter, 1 surgical) were performed. In all patients, the shunt was closed with a significant reduction in portal pressure (27.7xa0±xa011.3 to 10.8xa0±xa01.8xa0mmHg; pxa0=xa00.016), significant growth of the portal vessels (0.8xa0±xa00.5 to 4.0xa0±xa02.4xa0mm; pxa0=xa00.037), and normalization of ammonia levels (202.1xa0±xa053.6 to 65.7xa0±xa09.6xa0μmol/L; pxa0=xa00.002) with no complications.ConclusionStaged CPSS closure is effective in causing portal vessel growth and treating hyperammonemia.

The Amplatzer duct occluder II additional sizes device for transcatheter PDA closure: Initial experience

To present our initial experience with the Amplatzer Duct Occluder II Additional Sizes (ADOIIAS) device.