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Biomedical subjects

Frank L Hanley

Publications and source records attributed to Frank L Hanley.

At least 19 recordsLinked to original sources
PubMed2006

Visual light spectroscopy reflects flow-related changes in brain oxygenation during regional low-flow perfusion and deep hypothermic circulatory arrest.

OBJECTIVES: Regional low-flow perfusion has been used to minimize ischemic brain injury during complex heart surgery in children. However, optimal regional low-flow perfusion remains undetermined. Visible light spectroscopy is a reliable method for continuous determination of capillary oxygen saturation (SgvO2). We used visible light spectroscopy to follow deep and superficial brain SgvO2 during cardiopulmonary bypass, regional low-flow perfusion, and deep hypothermic circulatory arrest. METHODS: Visible light spectroscopy probes were inserted into the superficial and deep brain of neonatal (3.9-4.5 kg) piglets, targeting the caudate and thalamic nuclei. The piglets were subjected to cardiopulmonary bypass and cooled to a rectal temperature of 18 degrees C using pH stat. Regional low-flow perfusion was initiated through the innominate artery at 18 degrees C, and pump flows were adjusted to 40, 30, 20, and 10 mL/kg/min for 10-minute intervals followed by 30 minutes of deep hypothermic circulatory arrest. Regional low-flow perfusion was reestablished, and flows were increased in a stepwise manner from 10 to 40 mL/kg/min. SgvO2 was continuously monitored. Carotid flow was measured using a flow probe, and cerebral blood flow (milliliters per kilogram body weight per minute) was calculated. RESULTS: There were no significant differences between the deep and superficial brain tissue oxygenation during regional low flow brain perfusion before deep hypothermic circulatory arrest. However, after deep hypothermic circulatory arrest, the superficial brain SgvO2 was lower than the deep brain SgvO2 (24 +/- 12 vs 55.3 +/- 8, P = .05, at flows of 30 mL/kg/min, and 34.2 +/- 17 vs 62.5 + 8, P = .06, at a flow rate of 40 mL/kg/min). During regional low-flow perfusion, SgvO2 was maintained at flows of 30 to 40 mL/kg/min (cerebral blood flows of 15 to 21 mL/kg/min and 19 to 24 mL/kg/min, respectively), but was significantly lower at pump flows of 20 mL/kg/min (cerebral blood flow of 10 to 14 mL/kg/min) and 10 mL/kg/min (cerebral blood flow of 5 to 9 mL/kg/min) compared with the values obtained just before regional low-flow perfusion (pre-deep hypothermic circulatory arrest, 37 +/- 6 vs 65.5 +/- 4.4, P < .05, and 21.6 +/- 3.7 vs 65.5 +/- 4.4, P < .01, respectively; and post-deep hypothermic circulatory arrest, 32 +/- 4.5 vs 65.5 +/- 4.4, P < .05, and 16.6 +/- 4.7 vs 65.5 +/- 4.4, P < .01, respectively). CONCLUSIONS: Regional low-flow perfusion at pump flows of 30 to 40 mL/kg/min with resulting cerebral blood flows of 14 to 24 mL/kg/min was adequate in maintaining both deep and superficial brain oxygenation. However, lower pump flows of 20 and 10 mL/kg/min, associated with cerebral blood flow of 9 to 14 mL/kg/min, resulted in significantly reduced SgvO2 values.

Animals↗
PubMed2006

Coarctation of the aorta in the right aortic arch with left aberrant innominate artery.

Right aortic arch with an aberrant left innominate artery is a rare combination. We report a unique case of coarctation of the aorta in a patient with right aortic arch and aberrant left innominate artery. The diverticulum of Kommerell gave rise to the left innominate artery and a left ligamentum arteriosum, completing a vascular ring. This unusual case raises interesting points regarding the development of coarctation in the context of a right-sided arch and the approach to management of these patients.

Abnormalities, Multiple↗
PubMed2006

Homograft valved right ventricle to pulmonary artery conduit as a modification of the Norwood procedure.

BACKGROUND: The use of a right ventricle to pulmonary artery (RV-PA) conduit in the Norwood procedure has been proposed to increase postoperative hemodynamic stability. A valve within the conduit should further decrease RV volume load. We report our clinical experience with this modification. METHODS AND RESULTS: From February 2002 through August 2005, we performed 88 consecutive Norwood procedures using RV-PA conduits. We used composite valved conduits made from cryopreserved homograft and polytetrafluoroethylene (PTFE) in 66 cases (54 pulmonary, 12 aortic homografts), other valved conduits in 14, and unvalved PTFE in 8 cases. Hospital survival was 88.6% overall and increased to 93.1% after the initial year. Early interventions were required in 18 patients (16 for cyanosis). Prestage II cardiac catheterization was performed at a mean age of 126 days. Mean Qp/Qs was 1, with mean aortic saturation 71%, mean O2 extraction 24%, and mean right ventricular end-diastolic pressure 9 mm Hg. Patient weight, use of an aortic homograft valve in the conduit, stage I palliation within the first year of our experience, and low O2 extraction and high transpulmonary gradient prestage II were risk factors for overall death. Early interventions were more frequent in aortic valve conduits compared with all other conduits. CONCLUSIONS: The valved RV-PA conduit was associated with low early mortality after the Norwood procedure. The majority of these patients had normal cardiac output and well-maintained RV function. There may be a higher risk for early conduit interventions and death when aortic valve homografts are used in the RV-PA conduit.

Aortic Arch Syndromes↗
PubMed2006

Ductus-associated proximal pulmonary artery stenosis in patients with right heart obstruction.

Proximal pulmonary artery stenosis is a common acquired lesion in infants treated for congenital heart disease. We hypothesized that a large number of stenoses develop at the site of ductal insertion in patients with right ventricular outflow tract obstruction (RVOTO) and that these patients are at risk for developing hypoplasia of the ipsilateral pulmonary artery. The surgical and cardiac catheterization databases at our institution during the years 1988-2000 were searched for all patients under 1 year of age carrying a diagnosis of pulmonary atresia with intact ventricular septum (PA), tetralogy of Fallot (TOF) or pulmonary stenosis (PS), yielding 700 patients (62 PA, 373 TOF, 265 PS). The cardiac catheterization database was also searched for all patients with any diagnosis under 1 year of age found at catheterization to have proximal pulmonary artery stenosis. Proximal pulmonary artery stenosis associated with the ductal insertion site was diagnosed at catheterization in 33 infants (18 with PA, 5 with TOF, 6 with PS, 4 other diagnoses). This represents 29% of patients with PA, 1% with TOF and 2% with PS. Among patients with RVOTO and ductal insertion site-associated stenosis, there was a high prevalence (59%) of associated distal pulmonary arterial hypoplasia, defined as diameter of the stenosed vessel at first distal branch < or = 80% the diameter of the contralateral vessel. Symptomatology failed to identify this lesion; therefore, a high index of suspicion is necessary if proximal pulmonary artery stenosis is to be detected early in these patients.

Arterial Occlusive Diseases↗
PubMed2006

Profile of serum S100beta levels during maturation in fetal and neonatal sheep.

Serum levels of the protein S-100beta are dependent on three factors: rate of production, permeability of the blood-brain barrier, and rate of clearance. In the developing fetus and neonate all of these factors change at different rates. This study was performed to determine how serum S-100 levels varied during fetal and early postnatal life. Blood samples were obtained from 41 fetal and neonatal lambs. The blood was separated in a centrifuge and the serum drawn off and assayed for S-100beta using a commercially available radioimunoassay kit. S-100beta did not appear in the blood until halfway through pregnancy. Thereafter, levels steadily increased until 1 month after birth. Following this, S-100beta levels decreased progressively until by 1 year of age, they had reached a plateau. S-100beta levels change significantly with normal fetal and neonatal maturation. Valid interpretation of other data from subjects of similar developmental stage must take into consideration this physiological variation.

Animals↗
PubMed2006

Unifocalization of major aortopulmonary collaterals in single-ventricle patients.

BACKGROUND: Unifocalization of major aortopulmonary collateral arteries (MAPCAs) in pulmonary atresia with ventricular septal defect and intracardiac repair has become the standard of care. However, there are no reports addressing unifocalization of MAPCAs in single-ventricle patients. It is unknown whether their pulmonary vascular bed can be reconstructed and low enough pulmonary vascular resistance achieved to allow for superior or total cavopulmonary connections. METHODS: We reviewed data on all patients with functional single ventricles and unifocalization procedures of MAPCAs. From 1997 to 2005, 14 consecutive children with various single-ventricle anatomies were operated on. RESULTS: Patients had a median of three surgical procedures (range, 1 to 5). Two patients had absent, all others diminutive central pulmonary arteries, with an average of 3.5 +/- 1.2 MAPCAs. Seven patients (50%) had bidirectional Glenn procedures, and 3 of these had Fontan procedures. Median postoperative pulmonary artery pressures measured 12.5 mm Hg (Glenn) and 14 mm Hg (Fontan), respectively. Six patients are alive today (46%), with 1 patient lost to follow-up. Three patients died early and 3 late after initial unifocalization to shunts. One other patient survived unifocalization, but was not considered a candidate for a Glenn procedure and died after high-risk two-ventricle repair. Another patient with right-ventricle-dependent coronary circulation died of sepsis late after Glenn. CONCLUSIONS: In selected patients with functional single ventricles and MAPCAs, the pulmonary vascular bed can be reconstructed sufficiently to allow for cavopulmonary connections. Venous flow to the pulmonary vasculature decreases cardiac volume load and is likely to increase life expectancy and quality of life for these patients.

Abnormalities, Multiple↗
PubMed2006

The extracardiac conduit Fontan operation using minimal approach extracorporeal circulation: early and midterm outcomes.

OBJECTIVE: Our approach to the extracardiac conduit Fontan operation has evolved over time from full-pump, to partial-pump, to completely off-pump. This study is designed to report our overall experience with the extracardiac conduit Fontan operation and to evaluate the evolution in bypass technique on postoperative outcomes. METHODS: From September 1992 to April 2005, 285 patients, median age 4.5 years (1.4-44 years), median weight 16 kg (9.4-94 kg), underwent a primary extracardiac conduit Fontan procedure. Early and late outcomes were analyzed for the entire cohort and for 2 patient groups depending on whether an oxygenator was used in the bypass circuit (166 patients; 58%) or not (119 patients; 42%). RESULTS: Early failure (including death and takedown) occurred in 7 patients (2.5%). Prevalence of new early postoperative sinus node dysfunction necessitating a permanent pacemaker was 0.4%, and that of new tachyarrhythmias necessitating discharge home on a regimen of antiarrhythmia medications was 2.5%. Ten-year actuarial freedom from Fontan failure, new sinus node dysfunction necessitating a permanent pacemaker, and reoperation for conduit thrombosis or stenosis was 90%, 96%, and 98%, respectively. Fenestration rate was lower (P = .001) in the no-oxygenator group (8%) than in the oxygenator group (25%). Patients in the no-oxygenator group had lower intraoperative Fontan pressure (12.0 +/- 2.3 vs 13.5 +/- 2.4 mm Hg, P < .001), common atrial pressure (4.6 +/- 1.8 vs 5.3 +/- 1.8 mm Hg, P = .003), and transpulmonary gradient (7.5 +/- 2.1 vs 8.3 +/- 2.2 mm Hg, P = .013) than did the oxygenator group. CONCLUSIONS: The extracardiac conduit Fontan operation coupled with minimal use of extracorporeal circulation is associated with favorable intraoperative hemodynamics, low fenestration rate, minimal risk of thrombosis or stenosis, and minimal early and late rhythm disturbance.

Adolescent↗
PubMed2006

Esophageal saturation during antegrade cerebral perfusion: a preliminary report using visible light spectroscopy.

BACKGROUND: Visible light spectroscopy (VLS) is newer technology that measures real-time tissue oxygenation. It has been validated in detecting mucosal ischemia in adults. During complex neonatal heart surgery, antegrade cerebral perfusion (ACP) maintains cerebral saturation. Whether ACP maintains peripheral tissue perfusion in humans is not known. METHODS: Five patients undergoing neonatal open heart surgery with hypothermic cardiopulmonary bypass (CPB) were studied using a VLS esophageal probe in addition to bilateral near infrared cerebral oximetry. Three of five patients required ACP for arch repair, while two patients did not. VLS and cerebral saturation data were collected and analyzed in 5 min intervals prior to CPB, during CPB, and during ACP. RESULTS: In the two patients undergoing heart surgery with routine hypothermic CPB, both cerebral and esophageal saturations were maintained. However in all three neonates requiring ACP, although cerebral saturations did not decrease, esophageal saturation fell below the ischemic threshold (35%). Following establishment of normal CPB, esophageal saturation returned to baseline. CONCLUSIONS: Antegrade cerebral perfusion maintains cerebral oxygen delivery, however, it does not adequately perfuse the esophagus in neonates. This could have clinical implications.

Brain Ischemia↗
PubMed2005

Aortopulmonary window with anomalous origin of the right coronary artery from the pulmonary artery: two cases highlighting the importance of complete pre-operative echocardiographic evaluation of the coronary arteries in all conotruncal anomalies.

This report describes two infants with an aortopulmonary window in association with anomalous origin of the right coronary artery from the pulmonary artery. In both cases the diagnosis was made pre-operatively by transthoracic echocardiography, with the initial clue being extensive collateral flow within the myocardium. In each case there was surgical confirmation of the echocardiographic findings. These two cases demonstrate that coronary artery evaluation should be an integral part of every new echocardiographic evaluation, particularly in the setting of conotruncal anomalies.

Aortopulmonary Septal Defect↗
PubMed2005

Neonatal brain protection and deep hypothermic circulatory arrest: pathophysiology of ischemic neuronal injury and protective strategies.

Deep hypothermic circulatory arrest (DHCA) has been used for the past 50 years in the surgical repair of complex congenital cardiac malformations and operations involving the aortic arch; it enables the surgeon to achieve precise anatomical reconstructions by creating a bloodless operative field. Nevertheless, DHCA has been associated with immediate and late neurodevelopmental morbidities. This review provides an overview of the pathophysiology of neonatal hypoxic brain injury after DHCA, focusing on cellular mechanisms of necrosis, apoptosis, and glutamate excitotoxicity. Techniques and strategies in neonatal brain protection include hypothermia, acid base blood gas management during cooling, and pharmacologic interventions such as the use of volatile anesthetics. Surgical techniques consist of intermittent cerebral perfusion during periods of circulatory arrest and continuous regional brain perfusion.

Adult↗
PubMed2005

Preliminary results of fetal cardiac bypass in nonhuman primates.

OBJECTIVE: Fetal cardiac surgery has potential benefits for treatment of some congenital heart defects. However, placental dysfunction as a result of fetal bypass, fetal stress, and fetal exposure to external milieu needs to be overcome to optimize the outcomes of fetal cardiac bypass. In this study we evaluated the technical feasibility of cardiac bypass in the nonhuman primate fetus and the efficacy of different anesthetic approaches. METHODS: Twelve baboon fetuses, average gestation 146 +/- 8 days and weight 696 +/- 184 g, were used. Three fetuses were excluded from the study because of nuchal cord presentations. The animals were separated into two anesthesia groups: isoflurane (n = 6) and fentanyl and midazolam (n = 3). A miniature roller pump circuit without oxygenator was used for fetal bypass for 30 minutes. No blood transfusion was performed. Fetal blood gas samples were collected before bypass, during bypass, and at 15 and 60 minutes after bypass. RESULTS: All fetuses in the isoflurane group were successfully placed on the cardiac bypass circuit. However, 2 animals in the fentanyl and midazolam group were not placed on the bypass circuit because of sustained elevation in maternal uterine tone. All maternal baboons survived. Of the 6 fetuses in the isoflurane group, 5 survived for 60 minutes; however, placental function continued to deteriorate after bypass (Pa o 2 33 +/- 3 mm Hg before bypass, 23 +/- 6 mm Hg 15 minutes after, and 18 +/- 9 mm Hg 60 minutes after). CONCLUSION: The technical feasibility of cardiac bypass in nonhuman primate fetuses weighing less than 1000 g was confirmed. Isoflurane anesthesia appears to be superior to fentanyl and midazolam anesthesia for fetal cardiac surgery because of adequate uterine relaxation.

Anesthesia, General↗
PubMed2004

Pulmonary expression of the hepatocyte growth factor receptor c-Met shifts from medial to intimal layer after cavopulmonary anastomosis.

OBJECTIVE: Pulmonary arteriovenous malformations occur in up to 60% of patients after cavopulmonary anastomosis. We compared the effects of cavopulmonary anastomosis and pulmonary artery banding on lung gene expression in an ovine model to study the abnormal pulmonary vascular remodeling after the exclusion of inferior vena caval blood independent of reduced pulmonary blood flow. We previously demonstrated by contrast echocardiography that pulmonary arteriovenous malformations develop by 8 weeks after cavopulmonary anastomosis but not after pulmonary artery banding. Hepatocyte growth factor, a pleiotropic factor with morphogenic, mitogenic, and angiogenic activities, signals via its specific receptor c-Met to induce the antiapoptotic factor Bcl-2. In this study, we examined pulmonary artery expression of these factors and their potential role in pulmonary artery remodeling after cavopulmonary anastomosis and pulmonary artery banding. METHODS: Eighteen lambs aged 35 to 45 days were placed into 3 groups: cavopulmonary anastomosis, pulmonary artery banding, and control (n = 6/group). In the cavopulmonary anastomosis group, the superior vena cava was anastomosed to the right pulmonary artery in an end-to-end fashion. In the pulmonary artery banding group, the left pulmonary artery was banded to reduce blood flow to 20% of control. The control group had a simple right pulmonary artery clamp for 30 minutes. Lung was harvested for Western blot, reverse transcriptase-polymerase chain reaction, and immunostaining at 2 weeks (n = 3/group) and 5 weeks (n = 3/group) after surgery. RESULTS: The expression of c-Met mRNA after cavopulmonary anastomosis was increased by twofold compared with the control or pulmonary artery banding group. The total lung expression of c-Met by Western blot was also up regulated at 2 weeks (P <.05). However, total lung expression of hepatocyte growth factor and Bcl-2 by Western and reverse transcriptase-polymerase chain reaction was not different from the control and pulmonary artery banding groups at both 2 and 5 weeks after surgery. Immunohistochemical analysis revealed that c-Met expression was localized to the intimal layer of the pulmonary artery in the cavopulmonary anastomosis, while its expression in the control and pulmonary artery banding lungs was localized to the medial layer. Localization of Bcl-2 on the intimal layer in lambs with cavopulmonary anastomosis followed the same pattern as c-Met. CONCLUSIONS: After cavopulmonary anastomosis, pulmonary artery expression of the hepatocyte growth factor receptor c-Met and one of its downstream effectors, Bcl-2, had increased in the intimal layer and decreased in the medial layer. Because the hepatocyte growth factor signaling promotes increased endothelial cell survival, it may have a role in pulmonary artery remodeling following cavopulmonary anastomosis. In addition, the change of c-Met expression in the medial layer after cavopulmonary anastomosis suggests a possible mechanism for the smooth muscle cell alteration related to abnormal angiogenesis.

Animals↗
PubMed2004

A method for selectively limiting lumen diameter in corrosion casting.

Corrosion casting is a technique frequently used to evaluate the form and spatial relationship of three dimensional biological structures, such as vascular networks, in vitro [Scann. Microsc. 5 (1991) 1097; Schraufnagel, D.E. The lung microstructure. In: Motta, P.M., Murakami, T. Fujita, H. eds. Scanning Electron Microscopy of Vascular Casts: Methods and Applications. Boston: Kluwer Academic Publishers; 1992:123-137]. However, because corrosion casts tend to reproduce the complexity of surrounding vascular structures as well as the structures of interest, the use of this technique in highly complex vascular systems may obscure important changes such as A-V shunts because they may get lost among the myriad of capillaries. We developed a novel modification for creating vascular corrosion casts by utilizing polystyrene microspheres to selectively embolize normal capillary networks and thereby reduce the overall complexity of the cast. his technique may aid investigators in the evaluation of a variety of vascular beds and is useful in demonstrating non-capillary arteriovenous communications.

Animals↗
PubMed2003

Electrical resynchronization: a novel therapy for the failing right ventricle.

BACKGROUND: Many patients with congenital heart disease develop right ventricular (RV) failure due to anatomy and prior therapy. RV problems may include right bundle-branch block (RBBB), volume loading, and chamber enlargement. Because the failing RV may have regional dyskinesis, we hypothesized that resynchronization therapy might augment its performance. METHODS AND RESULTS: We studied 7 patients with RV dysfunction and RBBB, using a predefined pacing protocol. QRS duration, cardiac index (CI), and RV dP/dt were measured in 4 different pacing states. Atrioventricular pacing improved CI and RV dP/dtmax and decreased QRS duration as compared with atrial pacing or sinus rhythm. CONCLUSIONS: Atrioventricular pacing in patients with RBBB and RV dysfunction augments RV and systemic performance. RV resynchronization is a promising novel therapy for patients with RV failure.

Adolescent↗