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Biomedical subjects

Charles D Fraser

Publications and source records attributed to Charles D Fraser.

At least 19 recordsLinked to original sources
PubMed2006

Mechanical circulatory support as a bridge to combined dual organ transplantation in children.

The use of mechanical circulatory support as a bridge to cardiac transplantation is now an accepted therapeutic option. Also, as the criteria for organ transplantation have broadened, multi-organ transplantation has become more feasible. We report the cases of 2 children with end-stage heart failure and renal failure who were successfully bridged to combined, single-donor heart and kidney transplantation with mechanical circulatory support.

Adolescent↗
PubMed2006

Autologous Ross operation for congenital aortic stenosis.

Congenital aortic stenosis is a relatively common cardiac anomaly encountered in approximately 5% of all children with heart disease. The Ross procedure is increasingly used for replacement of the aortic valve in children. We report a 12-year-old boy who was born with congenital aortic stenosis secondary to a bicommissural aortic valve. The patient underwent open valvotomy in infancy and aortic valvuloplasty 2 years later. Residual/recurrent stenosis prompted referral for aortic valve replacement, and he underwent an autologous Ross procedure, in which the aortic root was replaced with a pulmonary autograft and the repaired aortic valve was used to restore right ventricular-to-pulmonary artery continuity. The postoperative course was unremarkable. Nitroprusside, esmolol, and labetolol were used to control postoperative hypertension. He was discharged 4 days after surgery on oral furosemide and aspirin, and he has had no cardiovascular symptoms during follow-up. Recent echocardiography demonstrated mild right ventricular outflow tract obstruction with a peak velocity of 3.6 m/sec, with a gradient of 42 mmHg and moderate pulmonary insufficiency. There was no left ventricular outlet tract obstruction or aortic insufficiency.

Anastomosis, Surgical↗
PubMed2006

Heterotaxy patients with total anomalous pulmonary venous return: improving surgical results.

BACKGROUND: Survival after repair of total anomalous pulmonary venous return in patients with heterotaxy syndrome has consistently been reported in the literature to be far inferior to the results obtained in nonheterotaxy patients. The outcomes of heterotaxy patients at Texas Children's Hospital undergoing repair of total anomalous pulmonary venous return were examined and compared with those of nonheterotaxy patients. METHODS: Between July 7, 1995, and November 22, 2005, 122 consecutive patients underwent primary repair of total anomalous pulmonary venous return. Characteristics were as follows: mean age, 0.35 +/- 1.8 years; mean weight, 4.3 +/- 2.8 kg; single ventricle, 40 (33%); heterotaxy, 38 (31%); pulmonary atresia, 13 (11%). Concomitant procedures included pulmonary artery banding in 4 (3%), systemic-to-pulmonary shunt in 14 (12%), bidirectional Glenn in 11 (9%), and other in 16 (14%). RESULTS: With a mean follow-up of 2.6 +/- 2.5 years including all patients, overall 30-day and 5-year survival was 93% and 86%, respectively; for heterotaxy patients it was 84% and 79%; and for nonheterotaxy patients it was 96% and 89%. Heterotaxy and nonheterotaxy survival curves were not significantly different (p> 0.05). Overall, there were 12 (9.8%) patients who required reoperation for pulmonary vein stenosis, at a mean of 5.1 +/- 5.5 months postoperatively. Seven (58%) reoperations were in heterotaxy patients. Rate of pulmonary vein reoperation is statistically greater (p < 0.05) for heterotaxy patients than nonheterotaxy patients. At last follow-up, all patients were in New York Heart Association class II or less. Using Cox proportional hazards models, pulmonary atresia and need for systemic-to-pulmonary shunt were risk factors for death (not heterotaxy). Single ventricle, operation after July 2000, and need for systemic-to-pulmonary shunt were risk factors for pulmonary vein reoperation. CONCLUSIONS: At midterm follow-up, heterotaxy patients undergoing total anomalous pulmonary venous return repair have a higher pulmonary vein reoperative rate but a comparable overall survival to nonheterotaxy patients.

Adolescent↗
PubMed2006

Interrupted aortic arch repair: aortic arch advancement without a patch minimizes arch reinterventions.

BACKGROUND: Surgical repair of interrupted aortic arch (IAA) remains challenging and is associated with significant mortality and incidence of late arch obstruction, as recently reported by the Congenital Heart Surgeons' Society (CHSS). In particular, the CHSS reported that any technique other than direct anastomosis with patch augmentation is a risk factor for arch reintervention. The experience at Texas Children's Hospital with IAA repair using an aortic arch advancement technique without a patch was examined. METHODS: Between July 1995 and December 2005, 60 patients underwent IAA repair using aortic arch advancement without a patch. Selective cerebral perfusion was used in 25 patients (42%). Cox proportional hazards models were used to analyze 20 variables to determine risk factors for death, arch reintervention, and left ventricular outflow tract (LVOT) reintervention. RESULTS: Median age was 8 days (range, 2 to 271 days) and weight was 3.0 kg (range, 1.7 to 6.1 kg). IAA types were A in 18 (30%) and B in 42 (70%). Associated anomalies were multiple congenital anomalies in 30 (50%) patients, DiGeorge syndrome in 21 (35%), LVOT obstruction in 26 (43%), a single ventricle in 11 (18%), and truncus arteriosus in 6 (10%). Mean follow-up was 3.0 +/- 2.6 years. Five-year freedom from aortic arch reintervention was 100%. Survival at 30 days, 1 year, and 5 years was 93%, 78%, and 76%, respectively. Since July 2000, two of 32 patients have died for an overall survival of 94%. Risk factors for death are older age, multiple congenital anomalies, DiGeorge syndrome, and bicuspid aortic valve. Selective cerebral perfusion was an independent protective variable for survival. Survival for an IAA patient with a ventricular septal defect and no complicating cardiac anomalies was 100%. CONCLUSIONS: Aortic arch advancement without a patch can be applied to IAA patients, with the expectation of a minimal need for arch reintervention. This technique affords an excellent survival, to which selective cerebral perfusion may be a contributing factor.

Abnormalities, Multiple↗
PubMed2006

Rapid ventricular remodeling with left ventricular unloading postventricular assist device placement: new insights with strain imaging.

We report the case of a 6-year old girl who presented with severe dilated cardiomyopathy. Cross-sectional echocardiography demonstrated a severely dilated hypokinetic left ventricle with an ejection fraction less than 10%. She developed intractable ventricular tachyarrhythmias and subsequently had a left ventricular assist device implanted. Within 1 week of mechanical support, echocardiography demonstrated dramatic reverse remodeling of the left ventricle with marked improvement in myocardial deformation using strain rate imaging. This report further highlights the potential for rapid remodeling after mechanical support of the failing myocardium.

Cardiomyopathy, Dilated↗
PubMed2006

Encouraging results for the Contegra conduit in the problematic right ventricle-to-pulmonary artery connection.

OBJECTIVE: The Contegra conduit was developed for right ventricular outflow tract reconstruction. This report evaluates the Contegra conduit, with focus on certain subpopulations in which conduits are known to perform poorly (ie, patients with previous homograft conduits and infants). METHODS: A retrospective review of 76 patients who had 77 Contegra conduits placed for right ventricular outflow tract reconstruction (January 2001 through August 2005) was completed. Characteristics include the following: median age of 1.6 years (range, 17 days-15.1 years), weight of 9.8 kg (range, 2.5-64.0 kg), and conduit diameter of 16 mm (range, 12-22 mm). Operations performed include right ventricular outflow tract reconstruction for pulmonary atresia-stenosis (n = 33), conduit exchange (n = 28), truncus repair (n = 7), primary conduit placement (n = 6), and the Ross procedure (n = 3). Seventy-nine percent were reoperations. RESULTS: There was no hospital mortality. Mean follow-up was 20 +/- 14 months. One-, 2-, and 3- year freedom from severe conduit regurgitation was 97%, 86%, and 81%, respectively, and freedom from severe conduit stenosis was 100%. Freedom from reoperation for conduit failure at 1 and 3 years is 98.3% and 93.1%, respectively. All conduit failures (n = 3) were for asymptomatic conduit pseudoaneurysms in the setting of multiple-level pulmonary branch stenoses. Survival at 3 years is 96%. Infants (n = 26) had a freedom from Contegra conduit failure at 3 years of 100%. Patients with previous homograft conduits (n = 26) had a freedom from Contegra conduit failure at 3 years of 100%. CONCLUSION: At midterm follow-up, the Contegra conduit remains a reliable, accessible, and easily implantable conduit for right ventricular outflow tract reconstruction. It appears to be the most promising conduit option for patients with previous homograft conduits and for infants.

Abnormalities, Multiple↗
PubMed2006

Transcutaneous near-infrared spectroscopy for detection of regional spinal ischemia during intercostal artery ligation: preliminary experimental results.

OBJECTIVE: Real-time information about regional spinal cord ischemia can guide intraoperative management and reduce the risk of paraplegia after thoracic aortic surgery. We hypothesized that near-infrared spectroscopy could provide such information during intercostal and lumbar artery ligation in pigs. METHODS: Transcutaneous near-infrared spectroscopic sensors were placed in the midline over the upper and lower thoracic vertebrae of 4 progressively larger pigs (weight range 21-70 kg). After the entire aorta was exposed, segmental arteries from T6 through L1 were sequentially ligated while regional oxygen saturation was monitored. Decreases in regional oxygen saturation were calculated as percentage changes from baseline. The degrees of ischemia in the upper and lower spinal cord were compared histopathologically. RESULTS: Baseline regional oxygen saturations were similar in the upper (68.8% +/- 9.0%) and lower (68.0% +/- 11.5%, P = .82) cord. After ligation, however, regional oxygen saturation levels were significantly lower in the lower cord (41.3% +/- 10.1%) than in the upper cord (64.8% +/- 9.3%, P = .037). The regional oxygen saturation had decreased by 39.0% +/- 11.5% in the lower cord but only by 6.3% +/- 7.6% in the upper cord (P = .026). This difference was confirmed microscopically: upper-cord sections had fewer ischemic neurons (8.8 +/- 9.4) than did lower-cord sections (21.3 +/- 13.6, P = .002). CONCLUSION: Intraoperative spinal cord ischemia was detectable with near-infrared spectroscopy in pigs weighing as much as 70 kg. The potential utility of this technique in patients undergoing thoracic aortic surgery warrants investigation.

Animals↗
PubMed2006

Preliminary experience with the MicroMed DeBakey pediatric ventricular assist device.

Mechanical circulatory support for both acute and chronic heart failure is a widely applied therapeutic option in the adult population with a variety of devices clinically available. Technology in this field has advanced sufficiently such that long-term support or "destination therapy" has become a generally accepted reality. Similar progress has not occurred in the field of device support for heart failure in children. While the number of potential patients is significantly lower in the pediatric population, the clinical relevance and poignancy of individual need are nonetheless real. Until recently, children with heart failure have been largely disadvantaged in comparison to their adult counterparts. The DeBakey VAD Child (MicroMed Technology, Inc, Houston, TX) represents a hopeful initial step in the direction of reducing the technological gap between adults and children. While the clinical experience with this device is limited at present, preliminary results are encouraging. This report will provide an overview of the DeBakey VAD Child, including device specifications, indications for clinical use, surgical and postoperative considerations, and updated clinical experience.

Adolescent↗
PubMed2006

Bilateral monitoring of cerebral oxygen saturation results in recognition of aortic cannula malposition during pediatric congenital heart surgery.

Congenital heart surgery is associated with a 2-25% reported incidence of neurological complication. Near-infrared spectroscopy (NIRS) can detect changes in regional cerebral saturation index (rSO2i) during cardiac surgery. If rSO2i decreases significantly, treatment algorithms are used to restore baseline values, potentially avoiding neurological complications. The efficacy of bilateral NIRS monitoring in pediatric congenital heart surgery has been debated. We report a case in which bilateral NIRS monitoring detected an abrupt decrease in rSO2i (right greater than left) after initiation of bypass without abnormalities detected by standard monitors. This resulted in prompt surgical intervention that restored rSO2i, potentially preventing neurological injury.

Brain Chemistry↗
PubMed2006

Innovative techniques for placement of implantable cardioverter-defibrillator leads in patients with limited venous access to the heart.

BACKGROUND: Because of venous occlusion, intracardiac shunting, previous surgery, or small size placement of implantable cardioverter-defibrillator (ICD) leads may not be possible using traditional methods. The purpose of this study was to evaluate and describe innovative methods of placing ICD leads. METHODS: The records of all patients undergoing ICD implantation at our institution were reviewed to identify patients with nontraditional lead placement. Indications for ICD, method of lead and coil placement, defibrillation thresholds, complications, and follow-up results were reviewed retrospectively. RESULTS: Eight patients (aged 11 months to 29 years) were identified. Six patients with limited venous access to the heart (four extracardiac Fontan, one bidirectional Glenn, one 8 kg 11-month-old) underwent surgical placement of an ICD coil directly into the pericardial sac. A second bipolar lead was placed on the ventricle for sensing and pacing. Two patients with difficult venous access had a standard transvenous ICD lead inserted directly into the right atrium (transatrial approach) and then positioned into the ventricle. All patients had a defibrillation threshold of <20 J, although one patient required placement of a second coil due to an elevated threshold. There have been no complications and two successful appropriate ICD discharges at follow-up (median 22 months, range 5-42 months). CONCLUSIONS: Many factors may prohibit transvenous ICD lead placement. Nontraditional surgical placement of subcutaneous ICD leads on the pericardium or the use of a transatrial approach can be effective techniques in these patients. These procedures can be performed at low risk to the patient with excellent defibrillation thresholds.

Adolescent↗
PubMed2006

Outcome of Glenn anastomosis for heterotaxy syndrome with single ventricle.

A retrospective study was undertaken of 157 patients who underwent a Glenn anastomosis between January 1996 and May 2001. Of these, 33 had heterotaxy syndrome: 20 males and 13 females, with a mean age of 1.26 +/- 2.8 years. Twenty-five had right atrial isomerism and 5 had left isomerism. A common atrioventricular valve was found in 24 patients, 18 had bilateral superior venae cavae, and 18 had anomalous pulmonary venous return. Repair was carried out in 8 patients with anomalous pulmonary venous return, and pulmonary artery augmentation was performed in 11. Compared to the 124 patients who had a Glenn operation for single ventricle without heterotaxy, there were significantly longer durations of mechanical ventilation, intensive care unit stay, and inotropic support, as well as higher mortality in the heterotaxy group. Heterotaxy syndrome with single ventricle still has a high rate of morbidity and mortality. Patients with severe atrioventricular valve regurgitation are at risk of early death. Complete Fontan circulation may not be possible in all patients, and Glenn anastomosis may be their final palliation.

Abnormalities, Multiple↗
PubMed2006

Complex pulmonary atresia in a neonate: successful surgical palliation for right pulmonary artery arising from the right main coronary artery.

We describe the case of a 3-week-old infant who was diagnosed with pulmonary atresia, a ventricular septal defect, and discontinuous pulmonary arteries. The pulmonary artery anatomy was delineated by angiography: the right pulmonary artery arose from the proximal right coronary artery, and the left pulmonary artery arose from a left ductus arteriosus. This case illustrates the importance of careful delineation of the anatomy in complex pulmonary atresia before surgical intervention.

Abnormalities, Multiple↗
PubMed2005

Combined lung and liver transplantation: the United States experience.

BACKGROUND: Combined transplantation of the lungs and liver is indicated for patients who would not be expected to survive transplantation of either organ alone. No single center has accumulated a significant experience, and as a result the expectations for this operation in the current era are unknown. METHODS: Patients that have undergone combined lung-liver transplantation in the United States were enrolled through the United Network for Organ Sharing Organ Procurement and Transplantation Network database. In addition, the English-language literature was searched for additional cases of combined lung-liver transplantation. RESULTS: Eleven patients have undergone combined lung and liver transplantation in the United States at different centers. The 1- and 5-year patient survival rates are of 79% and 63%, respectively, and no patient has required retransplantation. These patient survival rates are equivalent to similar a combined lung-liver case series from the United Kingdom (P=0.37, log-rank test) and isolated orthotopic liver transplantation in the United States (P=0.59, log-rank test), and are comparable to patient survival rates following isolated lung transplantation in the United States. CONCLUSIONS: Patient survival of combined lung-liver transplantation is comparable to that of isolated liver and isolated bilateral lung transplantation. This option should be considered for patients with end-stage lung disease and liver disease when transplantation of a single organ transplantation is precluded by severe disease in the other organ system.

Adolescent↗
PubMed2005

Congenital heart surgery 2005: the brain: it's the heart of the matter.

Operative mortality after repair of even the most complex congenital heart lesions has become rare. As such, the gaze of the surgical team has been diverted beyond that of early survival to focus on decreasing early and late morbidity. Important and concerning information is accumulating delineating the vulnerability of the neonatal brain to injury as the result of congenital heart disease and/or the techniques employed to correct the lesions. For many years the prevention of neurologic injury associated with congenital heart surgery has concentrated on "unraveling" the mysteries of the deleterious effects of intentional brain ischemia (in the form of deep hypothermic circulatory arrest) and developing methods to interrupt the pathway of irreversible injury. In the late 1990s, alternative perfusion techniques were developed to minimize or theoretically avoid the use of deep hypothermic circulatory arrest where it was once thought to be mandatory. Simultaneously, the rather routine use of noninvasive, real-time, neurologic monitoring has provided surgical teams the opportunity to intervene and prevent brain injury , thus eliminating the historic reliance on postoperative surrogate markers to define the presence of brain injury. It is yet undetermined whether these strategies will translate into improved short- and long-term neurologic outcome. Common to all surgical disciplines is a trend that as mortality decreases for a particular disease process, focus is adjusted, and refinements in treatment protocols are designed to minimize morbidity of the disease and its treatment. This natural refining process of a discipline's maturation is increasingly present in the field of congenital heart surgery.

Cardiac Surgical Procedures↗
PubMed2005

Aortic atresia and type B interrupted aortic arch: diagnosis by physiologic cerebral monitoring.

Physiologic cerebral monitoring has become an important part of our cardiovascular surgical unit. We recently encountered an unusual variant of aortic atresia that was first suggested by physiologic cerebral monitoring and required modification of our operative technique. We describe and discuss the anatomy, its translation into cerebral monitor findings, and how we modified our operative technique.

Aorta, Thoracic↗
PubMed2005

Neonates with aortic coarctation and cardiogenic shock: presentation and outcomes.

BACKGROUND: Some neonates with coarctation of the aorta (COA) present with cardiogenic shock and secondary end-organ injury. The management of this subgroup imposes unique challenges. We review our perioperative strategy and outcomes for neonates with COA who presented with cardiogenic shock. METHODS: Neonates (younger than 30 days) with isolated COA or COA with aortic arch hypoplasia were identified. Retrospective review was performed to identify and characterize patients who presented with cardiogenic shock, defined as impaired left ventricular (LV) or right ventricular (RV) systolic function, or both, respiratory failure requiring tracheal intubation, and metabolic acidosis. RESULTS: Thirteen neonates presented in cardiogenic shock and underwent surgical repair. No patients required catheter or surgical reintervention for recoarctation. There were no deaths at a mean follow-up of 54 months. Group I neonates (isolated COA, n = 7) underwent end-to-end anastomosis through left thoracotomy. The mean age and pH at presentation were 9 (+/-1.1) days and 7.07 (+/-0.21), respectively. The mean preoperative and postoperative LV myocardial performance indices (MPI) were 0.81 (+/-0.22) and 0.37 (+/-0.16), respectively (p = 0.002). Group II neonates (COA with arch hypoplasia +/- ventricular septal defect, n = 6) underwent aortic arch advancement and ventricular septal defect closure through median sternotomy. The mean time from diagnosis to surgery in group II was 5.5 (+/-1.9) days versus 2.4 (+/-1.5) days in group 1 (p = 0.01). The mean age and pH at presentation were 11.8 (+/-9.3) days and 7.02 (+/-0.21), respectively. The mean preoperative and postoperative LV MPI were 0.46 (+/-0.13) and 0.35 (+/-0.11), respectively (p = 0.02). The total hospital length of stay in group II patients was 18 (+/-6.23) days versus 11.3 (+/-5. 7) days in group I (p = 0.04). CONCLUSIONS: Timely intervention with a strategy individualized to the patient anatomy can be performed with excellent outcomes in neonates with COA and cardiogenic shock. Neonates with isolated COA had worse preoperative LV MPI, which reflects more significant global left ventricular systolic dysfunction in this subgroup. The elapsed time from diagnosis to surgery was decreased in neonates with isolated COA.

Aortic Coarctation↗
PubMed2005

Salvaging the failing Fontan: lateral tunnel versus extracardiac conduit.

BACKGROUND: Since Fontan revision has been demonstrated to provide hemodynamic and symptomatic improvement in select patients with failing Fontan circulations, we now believe it is important to determine if one type of revision (lateral tunnel [LT] or extracardiac conduit [ECC]) provides superior outcomes. METHODS: Thirty-five Fontan revisions were performed (Jun 1997 to Dec 2004): 19 ECC (54%) and 16 LT. Preoperative variables were similar: New York Heart Association (NYHA) IV (LT = 4 vs ECC = 2, p = not significant [NS]), preoperative arrhythmias (LT = 13 vs ECC = 16, p = NS) and systemic right ventricle (LT = 4 vs ECC = 2, p = NS). Twenty-eight patients (80%) underwent a modified maze procedure (LT = 12 vs ECC = 16, p = NS) and 29 (83%) had pacemaker placement (LT = 11 vs ECC = 18, p < 0.05). RESULTS: There were no hospital deaths and no arrhythmias at hospital discharge. There were no differences in mean duration of intubation (LT 0.6 vs ECC 0.9 days, p = NS), inotropic support (LT 1.5 vs ECC 2.1 days, p = NS), intensive care unit stay (LT 2.6 vs ECC 3.5 days, p = NS), hospital stay (LT 8.8 vs ECC 9.7 days, p = NS), or episodes of acute postoperative arrhythmias (LT = 2 vs ECC = 4, p = NS). On intermediate follow-up (29 +/- 22 months), the overall cohort had 94% survival, 97% of survivors in NYHA class I/II, 91% freedom from late arrhythmias requiring medication, and no patient required cardiac transplantation. Follow-up revealed no differences in NYHA I/II (LT = 14 vs ECC = 18, p = NS), mortality (LT = 2 vs ECC = 0, p = NS), or late arrhythmia (LT = 4 vs ECC = 4, p = NS). CONCLUSIONS: Both the LT and ECC revisions provide symptomatic benefit for a failing Fontan connection and have equivalent early and intermediate results including arrhythmia recurrence.

Adolescent↗