Combined atrial arterial switch operation (double switch) for hearts with Shone syndrome and pulmonary hypertension.
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Publications and source records attributed to D J Barron.
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UNLABELLED: The 3-year survival after small bowel transplantation (SBTx) has improved to between 73% and 88%. Impaired venous access for parenteral nutrition can be an indication for SBTx in children with chronic intestinal failure. AIM: To report our experience in management of children with extreme end-stage venous access. SUBJECTS: The study consisted of 6 children (all boys), median age of assessment 27 months (range, 13-52 months), diagnosed with total intestinal aganglionosis (1), protracted diarrhea (1), and short bowel syndrome (4), of which gastroschisis (2) and malrotation with midgut volvulus (2) were the causes. All had a documented history of more than 10 central venous catheter insertions previously. All had venograms, and 1 child additionally had a magnetic resonance angiogram to evaluate venous access. Five of 6 presented with thrombosis of the superior vena cava (SVC) and/or inferior vena cava. METHODS: Venous access was reestablished as follows: transhepatic venous catheters (5), direct intra-atrial catheter via midline sternotomy (4), azygous venous catheters (2), dilatation of left subclavian vein after passage of a guide wire and then placing a catheter to reach the right atrium (1), radiological recanalization of the SVC and placement of a central venous catheter in situ (1), and direct puncture of SVC stump(1). Complications included serous pleural effusion after direct intra-atrial line insertion, which resolved after chest drain insertion (1), displacement of transhepatic catheter needing repositioning (2), and SVC stent narrowing requiring repeated balloon dilatation. OUTCOME: Four children with permanent intestinal failure on assessment were offered SBTx, 3 of which were transplanted and were established on full enteral nutrition; the family of 1 child declined the procedure. In the remaining 2 children in whom bowel adaptation was still a possibility, attempts were made to provide adequate central venous access as feeds and drug manipulations were undertaken. One of them received liver and SBTx nearly 3 years after presenting with end-stage central venous access, because attempts to achieve independence from parenteral nutrition had failed. The other child died immediately after a transhepatic venous catheter placement, possibly from a nutritional depletion syndrome as no physical cause of death was found. Direct intra-atrial catheters in transplanted children proved to be adequate for the management of uncomplicated transplantation, although the usual infusion protocol had to be modified considerably, and the lack of access would have been critical if massive blood transfusion had been required during the transplant procedure. CONCLUSION: It was possible to reestablish central venous access in all cases. However, this was time consuming and difficult to assemble a skilled team consisting of one of more: surgeon, cardiologist, interventional radiologist, and transplant anesthetist. Small bowel transplantation is easier and safer with adequate central venous access, and we advocate liaison with an SBTx center at an early stage.
OBJECTIVE: To describe a 12 year experience with staged surgical management of the hypoplastic left heart syndrome (HLHS) and to identify the factors that influenced outcome. METHODS: Between December 1992 and June 2004, 333 patients with HLHS underwent a Norwood procedure (median age 4 days, range 0-217 days). Subsequently 203 patients underwent a bidirectional Glenn procedure (stage II) and 81 patients underwent a modified Fontan procedure (stage III). Follow up was complete (median interval 3.7 years, range 32 days to 11.3 years). RESULTS: Early mortality after the Norwood procedure was 29% (n = 95); this decreased from 46% (first year) to 16% (last year; p < 0.05). Between stages, 49 patients died, 27 before stage II and 22 between stages II and III. There were one early and three late deaths after stage III. Actuarial survival (SEM) was 58% (3%) at one year and 50% (3%) at five and 10 years. On multivariable analysis, five factors influenced early mortality after the Norwood procedure (p < 0.05). Pulmonary blood flow supplied by a right ventricle to pulmonary artery (RV-PA) conduit, arch reconstruction with pulmonary homograft patch, and increased operative weight improved early mortality. Increased periods of cardiopulmonary bypass and deep hypothermic circulatory arrest increased early mortality. Similar factors also influenced actuarial survival after the Norwood procedure. CONCLUSION: This study identified an improvement in outcome after staged surgical management of HLHS, which was primarily attributable to changes in surgical technique. The RV-PA conduit, in particular, was associated with a notable and independent improvement in early and actuarial survival.
OBJECTIVE: The purpose of the study was two-fold: (1) to highlight the varied presentation of mediastinal tuberculous lymphadenitis (MTL) in children and (2) to identify parameters, that may help in the early diagnosis of this condition. METHODS: Between January 1995 and December 2002, 13 children with histological diagnosis of MTL were retrospectively assessed for age at presentation, history of exposure to TB, presenting symptoms, investigations, initial diagnosis, surgical treatment and outcome. Stepwise multiple linear regression analysis was used to determine potential risk factors for early diagnosis of MTL. RESULTS: Thirteen children presented with: (a) fever, night sweats and weight loss (4); (b) acute respiratory distress (2); (c) cough and shortness of breath (SOB) (5); (d) stridor (1); and (e) chest pain (1). TB was suspected only in 6 children (46%) at presentation. In the other 7 cases (54%) the presumed diagnoses were: neuroblastoma (n=1), metastatic malignancy (n=1), bronchial polyp (n=1), bronchogenic cyst (n=2), and presumed foreign body (n=2). Bronchoscopy was diagnostic in identifying cheesy material within the bronchus and organisms on lavage in 4 (30%) and in identifying external compression in 2 (15%). Thoracotomy and excision of the lymph node mass was necessary to treat the mediastinal compression and to ascertain the diagnosis of TB in 3 children (23%). All 13 children had complete resolution of tuberculous lymphadenitis following anti-tuberculous treatment. The diagnostic clues in this cohort of patients were cough and SOB with history of exposure to tuberculosis (P=0.0001) and bronchoscopy and lavage with positive staining for acid-fast bacilli (P=0.0001). CONCLUSIONS: Tuberculosis was not suspected in 54% of children with MTL, and they posed diagnostic dilemma on admission. Bronchoscopy must be used as a diagnostic tool in children where tuberculosis cannot be excluded by radiology or specific skin tests. Thoracotomy and excision may be necessary to treat the obstructive symptoms.
OBJECTIVES: To review 13 years' data from a unit for grown ups with congenital heart disease (GUCH) to understand the change in surgical practice. METHODS: Records were reviewed of patients over 16 years of age undergoing surgery between 1 January 1990 and 31 December 2002 in a dedicated GUCH unit. Patients with atrial septal defects were included but not those with Marfan's syndrome or undergoing a first procedure for bicuspid aortic valves. Three equal time periods of 52 months were analysed. RESULTS: Of 474 operations performed, 162 (34.2%) were repeat operations. The percentage of repeat operations increased from 24.8% (41 of 165) in January 1990-April 1994 to 49.7% (74 of 149) in September 1998-December 2002. Mortality was 6.3% (n = 30). The median age decreased from 25.4 years (interquartile range 18.7) in January 1990-April 1994 to 23.9 (interquartile range 17.3) in September 1998-December 2002 (p = 0.04). The proportion of patients with a "simple" diagnosis decreased from 45.4% (74 or 165) in January 1990-April 1994 to 27.5% (41 of 149) in September 1998-December 2002 (p = 0.013). Pulmonary valve replacements in operated tetralogy of Fallot increased from one case in January 1990-April 1994 to 23 cases in September 1998-December 2002 and conduit replacement increased from five cases to 17. However, secundum atrial septal defect closures decreased from 35 cases to 14 (p < 0.0001). The estimated cost (not including salaries and prosthetics) incurred by an adult patient with congenital heart disease was pound2290 compared with pound2641 for a patient undergoing coronary artery bypass grafting. CONCLUSION: Despite the impact of interventional cardiology, the total number of surgical procedures remained unchanged. The complexity of the cases increased particularly with repeat surgery. Nevertheless, the patients do well with low mortality and the inpatient costs remain comparable with costs of surgery for acquired disease.
In conventional surgery for the associated lesions of congenitally corrected transposition of the great arteries, the right ventricle remains in the systemic circulation. In this situation, the right ventricle and tricuspid valve fail in an unpredictable manner. The double switch procedure was introduced to restore the morphologic left ventricle to the systemic circulation and considerable success has been seen over the last 10 years with this approach. The Rastelli and atrial switch procedure can be applied to patients with congenitally corrected transposition of the great arteries and pulmonary stenosis or atresia and a suitably placed ventricular septal defect in the outlet septum of the ventricle beneath the aortic valve. Thus, the left ventricle can be restored to the systemic circulation. The Rastelli-atrial switch is a complex operative procedure, but the operative risk and long-term results are good without evidence in the mid-term of ventricular failure as has been associated with the conventional repair. A disadvantage is that these patients require valved conduit changes over the years.
BACKGROUND: Atrophy and fibrosis of the distal part of the latissimus dorsi muscle (LDM) wrap is a recognized complication of cardiomyoplasty that has been attributed to ischemia. Failure of the muscle wrap contributes to the late attrition seen in clinical cardiomyoplasty. In this study we examined the role of two-staged mobilization and of preconditioning by electrical stimulation on the regional perfusion and oxygenation of the LDM. METHODS: In a rabbit model (n = 36) the LDM was preconditioned as follows: group A muscles received preconditioning in situ; group B muscles were partially mobilized by dividing the intercostal perforators and then preconditioned; and group C muscles were completely mobilized and wrapped around a silicone-rubber mandrel before conditioning. Controls received no conditioning. The preconditioning regimen consisted of 2 weeks of continuous stimulation at 2.5 Hz. At completion of preconditioning the muscles were fully mobilized and mounted on a muscle-testing apparatus. Purpose-built microelectrodes measured regional PO2 and perfusion using a diffusible gas tracer technique. Muscles were weighed and processed for fiber typing and capillary counting. RESULTS: All preconditioned muscles demonstrated fiber transformation, with increased fatigue resistance. Perfusion of preconditioned muscles both at rest and during contraction was higher than control in the proximal part of the muscle. Distal regions of group B muscles had higher perfusion and capillary density than any other group (p < 0.05). Distal regions of group C had the lowest perfusion and capillary density, and showed muscle atrophy and histologic evidence of necrosis. During fatigue testing there was a decrease in the PO2 in the distal regions of the control and group C muscles (p < 0.05), whereas it was maintained at resting levels in both group A and B muscles. CONCLUSIONS: Conditioning in situ improves perfusion of the distal LDM and prevents a fall in tissue PO2 during contraction. Two-stage mobilization further improves distal perfusion and capillary density. In contrast, shortterm elevation followed by conditioning produces impaired distal perfusion, decrease in PO2, and fiber necrosis in the distal muscle. The present study suggests that partial mobilization of the LDM performed at the same time as placement of electrodes for preconditioning may prepare the LDM better for the demands of cardiomyoplasty.
OBJECTIVE: In repair of truncus arteriosus the accepted methods of establishing right ventricle (RV) to pulmonary artery (PA) continuity utilize an allograft or xenograft valved conduit. Alternatively, the PA confluence may be directly anastomosed to the RV with anterior patch augmentation, which may allow growth and delay or avoid subsequent RVOT obstruction. These methods of RVOT reconstruction were evaluated in infants undergoing truncus arteriosus repair. METHODS: A retrospective analysis of 61 infants undergoing repair of truncus arteriosus between November 1988 and June 2000 was performed. Median age was 34 days (range 1 day to 6.4 months). The patient cohort was subdivided into two groups (1) Valved conduit group: RV to PA continuity performed with a conduit in 38 patients using allograft (28) or xenograft (10). (2) Direct anastomosis group: direct RV-PA anastomosis performed in 23 patients, augmented anteriorly with monocusp (15) or simple pericardial patch (eight). RESULTS: There were eight hospital deaths (13%, 95% confidence limits 5--21%). Hospital mortality did not differ significantly between group 1 and 2 (three patients (8%) versus five patients (22%) respectively, P=0.23). By multivariate analysis, low operative weight (P=0.023), severe truncal regurgitation (P=0.022) and major coronary abnormalities (P=0.018), were independent risk factors for hospital death. Hospital survivors were followed-up from 1.3 months to 11.8 years (mean 4.2+/-3.4 years). There were eight late deaths with survival of 73+/-6% at 2 years and beyond. Survival was not influenced by method of RVOT reconstruction (Conduit versus direct RV-PA anastomosis, 2.76+/-7%, 63+/-10%, respectively, P=0.23). Freedom from surgical RVOT reintervention was 56+/-10% in group 1 and 89+/-10% in group 2 at 10 years (P=0.023). The use of a xenograft conduit was an independent risk factor for reintervention (P<0.001). CONCLUSIONS: In truncus arteriosus repair, RV to PA continuity established by a direct anastomosis was associated with a low incidence of surgical RVOT re-intervention. This technique has the potential for RVOT growth and may be a useful alternative when an appropriate allograft is unavailable, particularly in the neonate where the risk of pulmonary hypertension are lower.
This paper defines the characteristics and significance of the scapular insertion of the latissimus dorsi muscle (LDM) of the rabbit. In a study of the New Zealand White species (n = 10) the scapular insertion was found to be a consistent anatomical feature of the LDM that made up 12.3% (+/-2.3) of the total muscle weight. The fibres arise from the medial aspect of the body of the LDM and run in a caudocranial direction to be inserted into a broad, thin tendon beneath the scapula ridge. This is morphologically different from the scapular component of the human LDM which is a well-recognized but inconsistent feature and consists of no more than a small leash of fibres running around the lower pole of the scapula. The scapular insertion was deeper red in colour than the body of the muscle and fibre-typing demonstrated a mean slow-fibre composition of 49% (+/-2.6) compared to 16% (+/-1.7) for the body of the muscle (p < 0.01). Mapping of the fibre types throughout the remainder of the LDM confirmed that the body of the muscle was of fast phenotype but with significantly more slow fibres in the superomedial segment of the muscle than elsewhere. This region of the muscle contributes mainly to the scapular insertion and it is proposed that this part of the muscle takes on a predominantly postural role in stabilising the scapula during movement of the forelimb.
The supply and utilization of oxygen by the myocardium reflect the dynamic efficiency of the microcirculation. The present study examines these parameters during coronary artery bypass surgery. We used a voltammetric microelectrode technique to assess regional variations in myocardial tissue partial pressure of oxygen (PO(2)) and myocardial tissue perfusion (MTP) in patients undergoing coronary artery bypass surgery. A total of 29 myocardial regions were studied in 17 patients to assay tissue PO(2), and 13 regions in 10 patients to measure MTP. There was an increase in MTP from 53+/-9 ml.min(-1).100 g(-1) before cardiopulmonary bypass to 72+/-13 ml. min(-1).100 g(-1) after (means+/-S.E.M.; P=0.05). Tissue PO(2) showed an overall increase from a baseline level of 45+/-8 mmHg to a final level of 88+/-10 mmHg (P<0.0001). Following release of the aortic cross-clamp there was a variable time delay before a change in tissue PO(2) was observed. There was an immediate response in five regions, whereas in 20 regions the response was delayed by between 0.5 and 32 min. In the remaining four regions there was no change in tissue PO(2). The duration of the delay in response was correlated positively with the cross-clamp time (r=0.45, P<0.05) and negatively with the final tissue PO(2) (r=-0.5, P<0.05). Voltammetric methods for monitoring changes in oxygen supply and utilization offer new insights into the changes that occur during ischaemia and reperfusion. A delay in the delivery of oxygen to the myocardium occurs in many patients following coronary artery bypass surgery.
Controversy persists over the efficacy of intercostal nerve block administered through a tunnelled extrapleural catheter. We have undertaken a randomized, prospective double-blind trial of two different local anaesthetic regimes to evaluate the effect of this technique on post-thoracotomy pain relief and pulmonary function. Sixty-eight patients were randomized to receive bupivacaine 0.25% (n = 22), lignocaine 1% (n = 21) or 0.9% NaCl (saline) (n = 20) via an extrapleural catheter, inserted peroperatively. All patients underwent a standard posterolateral thoracotomy. Pain was assessed using a visual analogue pain score and by the requirement for opiate analgesia. Pulmonary function was measured using bedside spirometry. Pain scores were lower in the local anaesthetic groups at 24, 32 and 72 h compared with placebo (P < 0.05) and the total amount of opiate required was less than placebo for both lignocaine and bupivicaine (P < 0.05). Pulmonary function was better in the local anaesthetic groups throughout the post-operative period and was most pronounced at 24 h with a mean improvement of 30% for forced expiratory volume (FEV1), 24% for forced vital capacity (FVC) and 19% for peak expiratory flow rate (PEFR) compared with placebo. There was no significant difference between pain scores, opiate requirement or pulmonary function between lignocaine and bupivicaine. CT scanning demonstrated containment of the local anaesthetic in an extra-pleural tunnel. Extra-pleural infusion of local anaesthetics is a simple technique, with low risk of complications and provides effective pain relief as well as an improvement in post-operative pulmonary function. Lignocaine is equally as effective as bupivacaine and its use would result in some cost-saving.
BACKGROUND: In the clinical application of transformed skeletal muscle to cardiac assistance there is evidence that the latissimus dorsi muscle (LDM) wrap can undergo atrophy, which would prevent it from providing a sustained functional improvement. Possible causes are ischaemia and degeneration related to the conditioning process. We studied the nutritional and structural changes occurring under different stimulation regimes with the aim of improving the conditioning protocol. METHODS: Microelectrodes were used to measure regional perfusion and oxygenation in the rabbit LDM during mobilisation and subsequent repeated contraction. Group A muscles (n = 10) were conditioned for 6 weeks at 10 Hz, Group B muscles (n = 10) for 2 weeks at 2.5 Hz. Each muscle was then mobilised and tested in a hydraulic apparatus which recorded the pressure generated in a closed circuit. RESULTS: Muscles of Group A and Group B demonstrated transformation of fibre type, with a predominance of type I (62 +/- 4%) fibres in Group A and type IIa (68 +/- 9%) fibres in Group B. There was no evidence of muscle degeneration. After 10 min of fatigue testing the pressure produced was 53 +/- 5% of initial values in Group A and 51 +/- 8% in Group B, compared to 8 +/- 1% in the control group (P < 0.001). Maximum rate of relaxation was faster in Group B than in Group A (46 +/- 3% vs. 36 +/- 3% of control muscle, P < 0.05). Mobilisation resulted in a decrease in the distal perfusion of the control muscles (P < 0.05) and PO2 decreased by 8.7 +/- 1.7 mmHg during a fatigue test, which resulted in rapid loss of contractile function to 46 +/- 1% of the initial value within 1 min. In both Groups A and B the perfusion of all regions of the muscles both before and after mobilisation was greater than that of controls. During the same fatigue test, the PO2 of the distal regions was maintained and the contractile function fell more slowly to between 70 and 80% of initial values within 1 min. CONCLUSION: We showed that ischaemia in the distal region of the control LDM could result from mobilisation and repeated contraction. Muscle transformation improved perfusion and prevented a fall in tissue PO2 during a sustained series of contractions. Muscles that were conditioned at 2.5 Hz shared the improved perfusion of the fully transformed muscle, but had faster relaxation characteristics. Short periods of in situ conditioning prior to mobilisation may help to avoid ischaemic changes in distal parts of the LDM while achieving fatigue resistance in the grafted muscle at an earlier postoperative stage.
BACKGROUND: The pedicled latissimus dorsi muscle flap is dependent upon an adequate blood supply via a single nutrient artery arising at its most proximal point. It has been suggested that when the latissimus dorsi muscle is used for cardiomyoplasty there is a risk of ischaemic damage to the distal regions of the flap under the additional metabolic stress of repeated electrical stimulation. METHODS: A rabbit model was developed in which the latissimus dorsi muscle was raised as a pedicled flap (n = 10). Needle microelectrodes were used to measure oxygenation and perfusion simultaneously in different regions of the muscle. Perfusion was measured using a gas tracer technique in which nitrous oxide was used as the marker. Muscle performance was measured by electrical stimulation of the mobilised flap. RESULTS: The mean (standard error) perfusion of the distal muscle fell significantly from 19.5 (6.2) to 11.9 (3.8) ml.min-1 100 g-1 (P < 0.05) as a consequence of mobilisation, although tissue oxygenation was maintained. Perfusion and pO2 of the proximal regions of the flap were unchanged. During electrical stimulation perfusion increased by 72 (12)% from resting levels in the proximal region, but by only 39 (8)% in the distal muscle. Tissue pO2 decreased during stimulation by 5.7 (1.8) mmHg proximally compared to 11.7 (3.7) mmHg distally P < 0.05). During recovery the pO2 remained below baseline for 24 minutes in the proximal muscle compared to 32 minutes in the distal muscle. CONCLUSIONS: Mobilisation results in a reduction in the perfusion of distal areas of the latissimus dorsi muscle flap. During repeated contraction the perfusion remains reduced and is unable to maintain tissue oxygen requirements. This has implications for dynamic applications of the latissimus dorsi muscle flap and supports the suggestion that ischaemia is the cause of distal muscle atrophy and fibrosis in cardiomyoplasty. Combined perfusion and pO2 data provide a new insight into muscle viability studies.
A variety of approaches and surgical techniques have been described for the management of recurrent coarctation. When there is an additional intracardiac defect that requires surgical correction it is preferable to correct both lesions simultaneously and through the same incision. This article reports two new techniques of connecting ascending to descending aorta using an intrathoracic conduit and performed through a median sternotomy.
We describe two patients who both suffered a cardiac arrest whilst maintained on an intra-aortic balloon pump. In an attempt to improve coronary and cerebral blood flow during cardiopulmonary resuscitation, the intra-aortic balloon was inflated to occlude the descending aorta and preferentially direct blood to the cerebral and coronary circulation. In case 1, mean radial artery pressure rose from 71/14 mmHg (mean = 33 mmHg) to 92/24 mmHg (mean = 47 mmHg). Diastolic right atrial pressure was 16 mmHg both with the balloon deflated and inflated. In patient 2, mean radial artery pressure rose from 48/21 mmHg (mean = 25 mmHg) to 62/26 mmHg (mean = 36 mmHg). Right atrial pressure was 90/6 mmHg (mean 34 mmHg) with the balloon deflated and 104/8 mmHg (mean = 40 mmHg) with the balloon inflated. Coronary artery perfusion pressure in case 1 increased from -2 to 8 mmHg and in case 2 increased from 15 to 18 mmHg. These results suggest that occlusion of the descending aorta during cardiac massage may improve coronary and cerebral perfusion pressures. Animal studies are consistent with these findings and show that aortic occlusion may significantly improve outcome from cardiac arrest.
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OBJECTIVE: Antibiotic-sterilised homograft valves stored at 4 degrees C have been implanted in the subcoronary position in this unit since 1973. This study was undertaken in order to assess the long-term function of these valves. METHODS: All 249 patients undergoing homograft aortic valve replacement (AVR) at the Wessex Cardiothoracic Centre between April 1973 and December 1994 were studied. Homograft valve sizes ranged from 15 mm to 28 mm internal diameter, 202 (81.1%) varying between 18 mm and 22 mm. The mean patient follow-up was 12.4 years with a total follow-up of 3096 patient-years. There were six early deaths (2.4%). RESULTS: On actuarial analysis, survival was 78.5+/-2.7% (1SE) at 10 years, 65.7+/-3.3% at 15 years and 55.0+/-3.9% at 20 years. The freedom from redo AVR was 87.9+/-2.4% at 10 years, 71.7 +/-3.8% at 15 years and 49.7+/-5.6% at 20 years. The freedom from structural degeneration was 85.6+/-2.5% at 10 years, 63.6+/-4.0% at 15 years and 41.9+/-6.4% at 20 years. On multivariate analysis the risk of valve failure was significantly higher in younger patients (P<0.0001) and in those who underwent aortic root tailoring (P = 0.024). The freedom from endocarditis was 98.4+/-0.9% at 10 years, 96.2+/-1.6% at 15 years and 95.1+/-1.9% at 20 years. Of the 249 patients, 218 had an isolated homograft AVR and were not anticoagulated. In this group there were two possible thromboembolic events. CONCLUSION: As well as the established haemodynamic benefits, this study has shown that homograft AVR with antibiotic-sterilised 4 degrees C stored homograft valves implanted in the subcoronary position, offers good long-term results.
Recent evidence has suggested that competitive flow is an important factor in early graft failure. In this case report an internal thoracic artery graft was used to revascularize an acute coronary artery dissection after balloon angioplasty. Subsequent angiography 4 months later showed complete healing of the dissection, yet the internal thoracic artery graft remained widely patent in spite of the maximal competitive flow from the native coronary artery. This concurs with experimental results recently reported in The Annals regarding the physiologic adaptability of the internal thoracic artery graft to suit flow requirements and its versatility as the conduit of choice.