Biomedical subjects
Publications and source records attributed to S Westaby.
Lord Hunt of Everest presented with aortic stenosis but predominant right ventricular failure. He was found to have signs of pulmonary hypertension with a dilated right ventricle, severe tricuspid regurgitation, and right atrial hypertrophy in the absence of elevated pulmonary artery pressures. He is a lifelong mountaineer and we attribute these findings to intermittent prolonged exposure to high altitude.
We used a Freestyle (Medtronic, Minneapolis, MN) porcine root to replace a regurgitant aortic valve and repair acute type A dissection. A Hemashield (Meadox Medicals, Oakland, NJ) graft was used to replace the ascending aorta with the "open anastomosis" technique. This method is a valuable alternative to conventional root replacement in acute type A dissection.
We describe successful management of pulmonary hypertension with a reversible aorto-pulmonary (central) shunt and inhaled nitric oxide gas after truncus arteriosus repair. A temporary central shunt may provide a lifeline in those cases refractory to pharmacologic pulmonary vasodilation as long as marginal systemic oxygenation can be maintained.
BACKGROUND: S100 protein has been suggested to be a serum marker for cerebral complications after cardiac operation and extracorporeal circulation. The aim of this study was to characterize the S100 release pattern after extracorporeal circulation in 515 consecutive patients undergoing coronary artery bypass grafting. METHODS: Clinical variables and outcome were prospectively registered. The cerebral outcome was determined by clinical examination. S100 was measured at the end of extracorporeal circulation, and after 5, 15, and 48 hours. RESULTS: After operation, 13 patients had stroke, 12 had delayed awakening, and 17 had encephalopathy. Early S100 release, immediately after extracorporeal circulation, was associated with age and perfusion time, but not with cerebral outcome. However, S100 release after 5 to 48 hours was associated with cerebral complications and risk factors for such outcome. Patients with stroke had higher S100 levels after 15 to 48 hours. A subset of patients with renal failure had overall higher S100 levels at 5 hours. CONCLUSIONS: Early and late S100 release indicate different mechanisms for release and emphasizes the potential power of this new biochemical marker for cerebral damage.
We describe a patient with left atrial myxoma followed by a second lesion in the left ventricle. Previous reports of "recurrent" myxoma were studied, with the following conclusions: There is little evidence for the process of myxoma seeding, local recurrence can occur through inadequate resection or malignant change, and many alleged recurrences are at a different site and multifocal disease occurs frequently in the familial setting.
BACKGROUND: There are few guidelines for surgical intervention late after unoperated traumatic aortic rupture. We reviewed our experience and the literature to determine when and how to operate. METHODS: Between 1987 and 1997, we treated 9 patients aged 22 to 82 years with chronic traumatic aneurysm. Seven patients underwent aneurysm resection. Two patients have not been operated on. The injury-to-operation interval ranged from 8 weeks to 18 years (mean, 4.1 years). One patient underwent median sternotomy and patch repair during hypothermic circulatory arrest. Six patients underwent left thoracotomy: 2 were operated on with left atrio-femoral bypass, and 4 with hypothermic circulatory arrest and ascending aortic cannulation. RESULTS: There was no surgical mortality or morbidity. The 2 patients who were not operated on remained asymptomatic without radiologic change in the aneurysm after follow-up of 2 and 9 years. CONCLUSIONS: From this limited experience and literature review, we make the following subjective observations: (1) all patients with new symptoms should be operated on promptly, and (2) asymptomatic densely calcified aneurysms detected more than 2 years after the accident can be observed by repeated tomography unless new symptoms arise.
We performed aortic root replacement using partial upper sternotomy in a patient with Marfan's syndrome. This approach was necessary because of severe pectus excavatum and spinal deformities. Although this method is technically feasible, we would not advocate it for routine use.
Intravenous leiomyomatosis is a condition characterized by intravenous growth of histologically benign smooth muscle tumor, originating in the uterus. A case of intravenous leiomyomatosis with right atrial extension in a 64-year-old woman is described. The atrial tumor was successfully removed with a single-stage approach via sternolaparotomy and total circulatory arrest using cardiopulmonary bypass.
BACKGROUND & PURPOSE: The indications and results of elective partial splenectomy in children remain uncertain. The aim of this study was to determine (1) the indications for elective partial splenectomy (EPS), (2) the extent of splenic resection, and (3) the complications of EPS. METHODS: Patients who underwent EPS from three centers over a 10-year period (1986 through 1996) were studied. Variables analyzed included clinical presentation and indications for EPS, extent of resection performed, perioperative transfusions, and complications. Postoperatively, splenic viability was determined by regular Doppler ultrasound scan and splenic function on peripheral blood film analysis. RESULTS: EPS was attempted in 12 children for various conditions: giant epithelial cyst (n = 6), hypersplenism and metabolic disease (n = 4), pseudotumor (n = 1), and abscess (n = 1). One procedure was converted to total splenectomy because of thin splenic tissue around an infected giant cyst. No child required transfusion for splenic bleeding. There were no postoperative complications or deaths. Only 7 of the 12 children received prophylactic preoperative immunisation. In the 11 successful cases splenic remnant viability remains confirmed by ultrasound scan and normal blood film. There has been no significant splenic regrowth or recurrent hypersplenism in the four children with metabolic disorders. CONCLUSIONS: EPS is suitable for benign splenic conditions and can be performed without major blood loss. Preoperative vaccination is advisable. Up to 95% of the spleen can be safely removed, basing the blood supply of the residual spleen tissue on peripheral polar vessels, with adequate postoperative function.
Explore the source record for details and available documents.
OBJECTIVE: Stentless valves convey important hemodynamic benefits but are used selectively depending on aortic root structure. The Freestyle valve (Medtronic, Inc, Minneapolis, Minn) is a versatile device that can be implanted by different methods depending on operating conditions. We aimed to demonstrate that a stentless valve could be used in every patient without increased risk of morbidity or mortality. We documented the effects of this valve on clinical outcome and left ventricular mechanics. METHODS: The Freestyle valve was implanted by the modified subcoronary method into 200 consecutive unselected patients who received a tissue valve in the aortic position and by root replacement in 2. Forty-three percent were older than 75 years. Forty percent underwent coronary bypass. Detailed clinical and echocardiographic follow-up (Food and Drug Administration protocol) was used out to 3 years. RESULTS: Mean ischemic time was 43+/-6 minutes for isolated aortic valve replacement and 63+/-14 minutes with concomitant procedures. Thirty-day mortality was 6%, none of the deaths being valve related. Hemodynamic function improved progressively with falling valve gradients and increased effective orifice areas. Left ventricular mass fell within normal limits over 2 years, but at 3 years there was a non-valve-related upswing. No instances of valve thrombosis, hemolysis, or paravalvular leak were noted. Less than 5% had mild to moderate aortic regurgitation. CONCLUSIONS: The Freestyle valve can be used in virtually every patient with aortic valve disease and provides superlative hemodynamic outcome. Hospital mortality and morbidity are similar to those reported for stented valves in an elderly population.
OBJECTIVE: Cannulation of the femoral artery is used routinely for hypothermic circulatory arrest operations on the aortic arch. A two-stage approach is advocated for combined arch and descending aortic disease. These methods are associated with important neurologic injury through embolism or malperfusion. We therefore changed to a central cannulation technique through extended left thoracotomy. METHODS: Eighteen patients with arch or combined pathologic conditions underwent one-stage repair with hypothermic circulatory arrest using ascending aortic cannulation and venous drainage from the pulmonary artery. Emergency operations were performed for bleeding or dissection. Cerebral and myocardial perfusion were restored during descending aortic replacement. RESULTS: One elderly patient died of gastrointestinal hemorrhage after initial recovery (overall mortality 5.6%, range 0.14% to 27%, p = 0.05). One possible transient monoparesis occurred but without computed tomographic scan evidence of embolism. No other significant events and no morbidity occurred from the surgical methods. CONCLUSIONS: Extended left thoracotomy with central cannulation allows safe one-stage replacement of the arch and descending aorta using anterograde cerebral perfusion. We believe that this method will reduce cerebral complications in arch and descending aortic operations.
Explore the source record for details and available documents.
The etiology of mitral valve disease is changing. The predominance of rheumatic pathology has given way to degenerative pathology in an increasingly elderly population. Mitral valve conservation by repair rather than replacement has several advantages. Repair is associated with a lower incidence of thromboembolism, hemolysis, and infectious endocarditis. For patients in sinus rhythm, thromboembolism is rare and anticoagulation can be discontinued. Repair also is associated with improved long-term survival. This article reviews the current literature on different types of surgical techniques for repair of the mitral valve and discusses future trends.
Explore the source record for details and available documents.
BACKGROUND: The risk of overt and subtle cerebral injury may be higher in intracardiac operation (ICO) rather than coronary artery bypass grafting (CABG). S-100 protein is a specific astroglial protein whose serum level increases after cerebral injury. Elevated serum levels of S-100 have been detected after adult cardiac operations and correlated with neurologic injury. METHODS: The level of S-100 protein was measured serially over 24 hours in 40 patients (27 undergoing aortic valve replacement, 9 mitral valve replacement, 4 closure of atrial septal defect) undergoing ICO and 20 patients undergoing CABG. RESULTS: The groups were similar with respect to age and cardiopulmonary bypass times. The S-100 level was not elevated before operation in any patient. Peak S-100 levels were reached at skin closure, when 35 of the ICO patients (88%) and 13 of the CABG patients (65%) had elevated S-100 levels. At skin closure peak S-100 levels were significantly greater in the ICO group (median [interquartile range], 0.76 [0.44-1.16] versus 0.3 [0-0.55] microgram/L; p < 0.01). At 5 hours S-100 levels were still elevated in 22 patients in the ICO group compared with 1 patient in the CABG group (p < 0.01), and at 24 hours 17 ICO patients had persistently elevated S-100 levels in comparison with 2 in the CABG group (p < 0.01). One valve patient had a stroke 24 hours after operation accompanied by a secondary increase in the S-100 level. There was no significant difference in postoperative S-100 levels between 5 patients in the ICO group with a prior history of stroke and those without. The peak S-100 level correlated with patient age (r = 0.59; p < 0.001) but not with the duration of cardiopulmonary bypass or core temperature during the operation. CONCLUSIONS: Intracardiac operation results in a significantly greater elevation in S-100 levels than CABG. Elevated S-100 levels correlate with increasing patient age but not with the duration of cardiopulmonary bypass or intraoperative core temperature. These findings raise the possibility that ICO patients may be more vulnerable to even subtle levels of cerebral injury than CABG patients.
BACKGROUND: The protective effect of desferrioxamine against myocardial ischemia-reperfusion injury remains uncertain. In this study we examined a broad range of ischemia-reperfusion indices to determine the effect of desferrioxamine cardioplegia in a model that reflects surgical practice. METHODS: Isolated rat hearts were subjected to 90 minutes of ischemia with cold cardioplegia, with or without 0.5-mmol/L desferrioxamine. Left ventricular mechanical function and the levels of thiobarbituric acid-reactive substances and nonprotein thiol compounds were measured after reperfusion. Electron microscopic analysis of mitochondria was performed using diaminobenzidine staining, together with histochemical staining for glycogen and marker enzymes in left ventricular muscle and the atrioventricular node. RESULTS: The desferrioxamine group showed better preservation of diastolic function (chamber stiffness coefficient at 15 minutes and maximum rate of decrease of left ventricular pressure at 45 minutes of reperfusion). Histochemical analysis showed that mitochondria-specific succinate dehydrogenase and the nonspecific esterase of the atrioventricular node were better preserved in the desferrioxamine group. CONCLUSIONS: The findings from this study indicate that there is added protection against ischemia-reperfusion injury when desferrioxamine is added to the cardioplegic solution; however, the study also highlighted that, in this clinically applicable model, desferrioxamine is not universally protective against all aspects of ischemia-reperfusion injury.
An infected tricuspid valve was successfully replaced with a fresh mitral homograft. This operation is preferable to valvectomy alone or the use of a stented prosthesis in terms of hemodynamics and resistance to infection.