| 1. |
- Boivie, Patrik, et al.
(författare)
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Embolic material generated by multiple aortic crossclamping : a perfusion model with human cadaveric aorta
- 2003
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - 0022-5223 .- 1097-685X. ; 125:6, s. 1451-1460
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Atherosclerosis of the ascending aorta and use of aortic crossclamping are risk factors for neurologic injury during cardiac surgery. OBJECTIVES: Repeated aortic manipulation is part of the surgical approach to most cardiac operations. The aim of this study was to assess the amount and size of particulate matter that is dislodged from the aortic wall as a function of repeated aortic crossclamping. METHODS: In 10 subjects undergoing autopsy the aorta was dissected and mounted in a perfusion model. The ascending aorta was crossclamped and washed out 10 times, with the perfusate collected in aliquots (1 to 10). The aliquots were examined by computerized image processing, both macroscopically and under the microscope for calcified and cellular material. RESULTS: Aortic crossclamping produced substantial output of particulate matter. After repeated aortic crossclamping the number of particles decreased (P =.012) and approached the baseline for aliquots 6 to 10. The average particle diameter was 0.63 +/- 0.03 mm, with a maximum of 4.74 mm. Similar variability in particle outputs were recorded microscopically, with findings of both calcified and cellular material. Nine of 10 aortas had calcifications seen during simple visual inspection. CONCLUSIONS: The washouts of dislodge material at aortic crossclamping had embolic potential. During the initial aortic crossclamping procedures the amount of particles was substantial, both macroscopically and microscopically. On the microscopic scale noncalcified cellular debris represents a significant pool of embolic material. Repeated aortic crossclamping reduced the amount of particles. These findings question surgical techniques associated with repeated aortic crossclamping.
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| 2. |
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| 3. |
- Baumgartner, R W, et al.
(författare)
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Microembolic signal counts increase during hyperbaric exposure in patients with prosthetic heart valves
- 2001
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 1097-685X .- 0022-5223. ; 122:6, s. 1142-1146
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Patients with prosthetic heart valves have an increased risk of thromboembolic events, and transcranial Doppler sonography reveals microembolic signals. Whereas microembolic signals were initially assumed to be of particulate matter, recent studies suggest that they are partially gaseous in origin. If this is true, alteration of environmental pressure should change microembolic signal counts. We undertook this study to evaluate the influence of hyperbaric exposure on microembolic signal counts in persons with prosthetic heart valves. METHODS AND RESULTS: Microembolic signal counts were monitored by transcranial Doppler sonography of both middle cerebral arteries under normobaria (normobaria 1), 2 subsequent periods of hyperbaria (2.5 and 1.75 bar), and a second period of normobaria (normobaria 2) in 15 patients with prosthetic heart valves. Each monitoring period lasted 30 minutes. Compression and decompression rates were 0.1 bar/min. Microembolic signal counts increased from 20 (12-78) at normobaria 1 to 79 (30-165) at 2.5 bar (P <.01 vs normobaria 1 and 2), decreased to 44 (18-128) at 1.75 bar (P <.01 vs normobaria 1 and 2.5 bar; P <.001 vs normobaria 2), and returned to 20 (8-96) at normobaria 2 (values are medians and 95% confidence intervals). CONCLUSIONS: Our results strongly suggest that gaseous bubbles are underlying material for part of the microembolic signals detected in patients with prosthetic heart valves.
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| 4. |
- Bech-Hansen, Odd, et al.
(författare)
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Assessment of effective orifice area of prosthetic aortic valves with Doppler echocardiography : An in vivo and in vitro study
- 2001
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 0022-5223 .- 1097-685X. ; 122:2, s. 287-295
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: We sought to evaluate the Doppler assessment of effective orifice area in aortic prosthetic valves. The effective orifice area is a less flow-dependent parameter than Doppler gradients that is used to assess prosthetic valve function. However, in vivo reference values show a pronounced spread of effective orifice area and smaller orifices than expected compared with the geometric area. Methods: Using Doppler echocardiography, we studied patients who received a bileaflet St Jude Medical valve (n = 75, St Jude Medical, Inc, St Paul, Minn) or a tilting disc Omnicarbon valve (n = 46, Medical CV, Incorporated, Inver Grove Heights, Minn). The prosthetic valves were also investigated in vitro in a steady flow model with Doppler and catheter measurements in the different orifices. The effective orifice area was calculated according to the continuity equation. Results: In vivo, there was a wide distribution with the coefficient of variation (SD/mean ╫ 100%) for different valve sizes ranging from 21% to 39% in the St Jude Medical valve and from 25% to 33% in the Omnicarbon valve. The differences between geometric orifice area and effective orifice area in vitro were 1.26 ▒ 0.41 cm2 for St Jude Medical and 1.17 ▒ 0.38 cm2 for Omnicarbon valves. The overall effective orifice areas and peak catheter gradients were similar: 1.35 ▒ 0.37 cm2 and 25.9 ▒ 16.1 mm Hg for St Jude Medical and 1.46 ▒ 0.49 cm2 and 24.6 ▒ 17.7 mm Hg for Omnicarbon. However, in St Jude Medical valves, more pressure was recovered downstream, 11.6 ▒ 6.3 mm Hg versus 3.4 ▒ 1.6 mm Hg in Omnicarbon valves (P = .0001). Conclusions: In the patients, we found a pronounced spread of effective orifice areas, which can be explained by measurement errors or true biologic variations. The in vitro effective orifice area was small compared with the geometric orifice area, and we suspect that nonuniformity in the spatial velocity profile causes underestimation. The St Jude Medical and Omnicarbon valves showed similar peak catheter gradients and effective orifice areas in vitro, but more pressure was recovered in the St Jude Medical valve. The effective orifice area can therefore be misleading in the assessment of prosthetic valve performance when bileaflet and tilting disc valves are compared.
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| 5. |
- Christiansson, Lennart, et al.
(författare)
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Aspects of the spinal cord circulation as assessed by intrathecal oxygen tension monitoring during various arterial interruptions in the pig
- 2001
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 0022-5223 .- 1097-685X. ; 121:4, s. 762-772
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: We sought to study the effect of various modes of interruption of the spinal cord blood supply on intrathecal oxygenation.METHODS: In 24 pigs intrathecal PO (2), PCO (2), and pH were continuously monitored with a multiparameter catheter (Paratrend 7, Biomedical Sensors; Diametrics Medical, Inc, St Paul, Minn) during and after aortic crossclamping or selective interruption of segmental arteries and proximal collateral circulation.RESULTS: Proximal aortic clamping (n = 6) produced complete ischemia, whereas a second clamp close to the celiac trunk (n = 4) partly protected against spinal cord ischemia. This is explained by prevention of the steal phenomenon in the excluded part of the aorta. Adding clamps to the subclavian arteries (n = 6) created complete spinal ischemia as the collateral circulation was interrupted. In another group (n = 4) all segmental arteries below T5 were occluded with no reaction in the intrathecal variables. Additional selective clamping of supreme intercostal arteries (n = 4) showed the relative importance of the subclavian and vertebral collateral pathways.CONCLUSIONS: Continuous intrathecal PO (2) was monitored during various modes of interruption of the spinal cord blood supply. This provided insight into the ischemia mechanisms and relative importance of the segmental contribution and proximal collateral pathways of the spinal cord circulation in pigs. A short literature review is given, and aspects of comparative anatomy are discussed.
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| 6. |
- Escobar Kvitting, John-Peder, 1976-, et al.
(författare)
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Flow patterns in the aortic root and the aorta studied with time-resolved, 3-dimensional, phase-contrast magnetic resonance imaging : implications for aortic valve–sparing surgery
- 2004
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 0022-5223 .- 1097-685X. ; 127:6, s. 1602-1607
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveSparing the aortic valve has become a surgical option for patients who require repair of aortic root ectasia and have normal valve leaflets. Surgical approaches to valve sparing differ with regard to preservation of the native sinuses of Valsalva. The role of the sinuses and the importance of maintaining them remain controversial.MethodsBy using a time-resolved, 3-dimensional, phase-contrast magnetic resonance imaging technique, aortic root and aortic blood velocity data were acquired from 2 patients with Marfan syndrome 6 months after aortic valve–sparing surgery with straight Dacron grafts and contrasted with data from 6 normal volunteers.ResultsIn normal aortas vortical blood flow became apparent in the individual sinuses after peak systole. The vortices filled the available space behind the valve leaflets and persisted until diastole, expanding and moving inward during aortic valve closure. In contrast, no vortices were observed in the postoperative patients with Marfan syndrome with negligible sinuses.ConclusionsChanges in supravalvular flow accompany loss of sinus architecture. Whether the presence, size, and velocity of supravalvular vortices affects the function or durability of the preserved aortic valve remains to be studied.
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| 7. |
- Gustafsson, Ronny, et al.
(författare)
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Vacuum-assisted closure therapy guided by C-reactive protein level in patients with deep sternal wound infection.
- 2002
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 1097-685X .- 0022-5223. ; 123:5, s. 895-900
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Deep sternal wound infection is a serious and potentially lethal complication of cardiac surgery when performed through a median sternotomy. We describe the outcome of a new treatment strategy with C-reactive protein level-guided vacuum-assisted closure used at our department. METHODS: Data from 16 consecutive adult patients who had deep sternal wound infections after cardiac surgery were reviewed. Patients with superficial infection or sterile dehiscence were not included. All patients with postoperative deep sternal wound infections were treated with first-line vacuum-assisted closure therapy, followed by direct surgical closure. A purpose-built vacuum-assisted closure system consisting of polyurethane foam pieces and a special pump unit was used. The foam was placed in the wound after debridement of foreign material and necrotic tissue. The wound was covered with adhesive drape and connected to the pump unit, which was programmed to create a continuous negative pressure of 125 mm Hg in the wound cavity. Intravenous antibiotics were given according to tissue-culture results. The patients were immediately extubated after the operation. When ingrowth of granulation tissue was observed in all parts of the wound and the plasma C-reactive protein level showed a steady decline to 30 to 70 mg/L or less without confounding factors, such as tissue injuries or concomitant infections, the sternotomy was rewired, and the wound was closed. RESULTS: All patients were alive and free from deep sternal wound infection 3 months after the operation. The median vacuum-assisted closure treatment time until surgical closure was 9 days (range, 3-34 days), and the median C-reactive protein level at closure was 45 mg/L (range, 20-173 mg/L). The median hospital stay was 22 days (range, 12-120 days). CONCLUSIONS: Early vacuum-assisted closure treatment, followed by surgical closure guided by the plasma C-reactive protein level, is a reliable and easily applied new strategy in patients with postoperative deep sternal wound infection.
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| 8. |
- Hellberg, Anders, et al.
(författare)
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Monitoring of intrathecal oxygen tension during experimental aortic occlusion predicts ultrastructural changes in the spinal cord
- 2001
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 0022-5223 .- 1097-685X. ; 121:2, s. 316-323
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To study the correlation between intrathecal PO2 and ultrastructural changes in the spinal cord during thoracic aortic occlusion in pigs. MATERIAL AND METHODS: In 18 pigs, online intrathecal oxygenation was monitored by a multiparameter Paratrend catheter (Biomedical Sensors, High Wycombe, United Kingdom) during 60 minutes' clamping of the proximal and distal descending thoracic aorta. The animals were randomly divided into 2 groups (A and B) depending on the level of distal aortic clamping. Distal aortic perfusion was restored through an aorto-iliac shunt, which also maintained low thoracic segmental perfusion of the spinal cord in group B. Perfusion-fixation technique was used before harvesting the spinal cord specimens, which later were evaluated with light and electron microscopy by an independent observer. Intrathecal parameters were interpreted as normal if PO2 was more than 0.8 kPa and PCO2 was less than 12 kPa, as intermediate ischemia if PO2 was 0.8 or less or PCO (2) was more than 12 kPa, and as absolute ischemia if PO2 was 0.8 or less and PCO2 was more than 12 kPa. RESULTS: Among 6 animals with ultrastructural changes of absolute spinal cord ischemia-reperfusion injury, 5 also had absolute ischemia according to variables derived by the Paratrend catheter. The 2 methods were in agreement in 3 of 5 animals with intermediate ischemia-reperfusion changes and in 5 of 6 animals with normal findings. The accuracy of cerebrospinal fluid PO2 and PCO2 to predict electron microscopy-verified intermediate or absolute ischemia-reperfusion injury was 94%. CONCLUSIONS: Monitoring of intrathecal PO2 after clamping of the descending aorta correlated with ultrastructural changes in the spinal cord in this pig model.
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| 9. |
- Johnell, Matilda, et al.
(författare)
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Coagulation, fibrinolysis and cell activation in patients and shed mediastinal blood during coronary artery bypass grafting using a new heparin-coated surface
- 2002
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 0022-5223 .- 1097-685X. ; 124:2, s. 321-332
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Heparin coating of the cardiopulmonary bypass circuit is shown to improve the biocompatibility of the surface. We have studied a new heparin surface, the Corline Heparin Surface, applied to a complete set of an extracorporeal device used during coronary artery bypass grafting in terms of activation of inflammation, coagulation, and fibrinolysis in patients and in shed mediastinal blood. METHODS: Sixty patients scheduled for coronary artery bypass grafting were randomized to one of 3 groups with heparin-coated devices receiving either a standard, high, or low dose of systemic heparin or to an uncoated but otherwise identical circuit receiving a standard dose of systemic heparin. Samples were drawn before, during, and after the operation from the pericardial cavity and in shed mediastinal blood. No autotransfusion of shed mediastinal blood was performed. RESULTS: The Corline Heparin Surface significantly reduced the activation of coagulation, fibrinolysis, platelets, and inflammation compared with that seen with the uncoated surface in combination with a standard dose of systemic heparin during cardiac surgery with cardiopulmonary bypass. Both a decrease and an increase of systemic heparin in combination with the coated heparin surface resulted in higher activation of these processes. A significantly higher expression of all studied parameters was found in the shed mediastinal blood compared with in systemic blood at the same time. CONCLUSIONS: The Corline Heparin Surface used in cardiopulmonary bypass proved to be more biocompatible than an uncoated surface when using a standard systemic heparin dose. The low dose of systemic heparin might not be sufficient to maintain the antithrombotic activity, and the high dose resulted in direct cell activation rather than a further anti-inflammatory and anticoagulatory effect.
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| 10. |
- Resch, Timothy, et al.
(författare)
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Changes in aneurysm morphology and stent-graft configuration after endovascular repair of aneurysms of the descending thoracic aorta
- 2001
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 1097-685X .- 0022-5223. ; 122:1, s. 47-52
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: We sought to study changes in morphology and stent-graft configuration of descending thoracic aortic aneurysms after endovascular repair. METHODS: Twenty-three patients treated with custom-made stent-grafts were studied. The stent-graft consisted of continuous, stainless-steel Z stents mounted within a polyester graft. In the last 11 cases the stents were interconnected with 3 longitudinal wires. Contrast-enhanced spiral computed tomography was performed preoperatively and at 1, 3, and every 6 months postoperatively. Angiography was used preoperatively and at 1-year follow-up. Proximal and distal necks were assessed for diameter and length. Aneurysm diameter, endoleaks, stent-graft migration, and changes in stent-graft configuration were evaluated. RESULTS: During follow-up (median, 18 months; range, 1-48 months), excluded aneurysms decreased in diameter by 4 mm (0.5-10 mm, P =.0018). Endoleaks prevented size decrease. Five patients displayed neck dilatation, 4 at both the proximal and distal fixation sites and 1 only distally. In 7 (30%) patients there was proximal migration of the distal end of the stent-graft. Three (13%) patients displayed both distal migration of the proximal end of the stent-graft and proximal migration of the distal end of the stent-graft. There was a significant correlation between stent-graft kinking and appearance of proximal or distal stent-graft migration (P =.05 and P =.0007, respectively). In no case did the migration lead to appearance of an endoleak before intervention was performed. CONCLUSION: Excluded descending thoracic aortic aneurysms decrease in size on midterm follow-up. A subgroup of patients prone to neck dilatation might exist. A combination of neck dilatation and vector forces acting on stent-grafts in the tortuous thoracic aorta might lead to stent-graft migration.
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