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2.
Kyobu Geka ; 73(8): 623-626, 2020 Aug.
Article in Japanese | MEDLINE | ID: mdl-32879294

ABSTRACT

A state in which thrombus is found in both right and left atria with thrombus penetrating the foramen ovale is called as impending paradoxical embolism (IPE). A 42-year-old man was found to have poor oxygenation and shock when his body was turned prone after induction of anesthesia. We inserted percutaneous cardiopulmonary support (PCPS), and his blood pressure was maintained. Transesophageal echocardiography revealed right heart pressure overload and left atrial thrombus. Computed tomography (CT) showed thrombosis in both main pulmonary arteries. The patient was judged to require emergency surgery. Bilateral pulmonary artery thrombus and thrombus between the right and left atria was removed under hypothermia using a heart-lung machine. Postoperatively, thrombus was detected in the bilateral posterior tibial vein and peroneal vein. He had a good postoperative course. There were few reports of IPE with pulmonary embolism that developed during operation.


Subject(s)
Embolism, Paradoxical , Pulmonary Embolism , Thrombosis , Adult , Echocardiography, Transesophageal , Heart Atria/diagnostic imaging , Humans , Male
3.
Clin Exp Nephrol ; 24(12): 1140-1143, 2020 Dec.
Article in English | MEDLINE | ID: mdl-32772208

ABSTRACT

BACKGROUND: Amelioration of hyperchloremic acidosis (Cl-Ac), a common complication in chronic kidney disease (CKD), could preserve renal function in chronic kidney disease (CKD). However, the development of Cl-Ac in CKD has not been clarified yet. METHODS: The degree of Cl-Ac, which is indicated as the bicarbonate concentration decrease with serum chloride concentration increase (∆[HCO3-]Cl), was compared with the estimated glomerular filtration rate (eGFR) by using CKD patient records. RESULTS: In 307 records with metabolic acidosis, a spline curve obtained from the plot comparing ∆[HCO3-]Cl with eGFR showed that ∆[HCO3-]Cl did not change, increased, and decreased during eGFR decrease until 27, from 27 to 17.5, and from 17.5 mL/min/1.73 m2, respectively. CONCLUSION: By CKD progression, Cl-Ac progressed and regressed at the CKD stages G4 and G5, respectively. The regression would have reflected the shift of Cl-Ac to high anion gap acidosis.


Subject(s)
Acid-Base Equilibrium , Acidosis/etiology , Chlorides/blood , Glomerular Filtration Rate , Kidney/physiopathology , Renal Insufficiency, Chronic/complications , Acidosis/blood , Acidosis/diagnosis , Acidosis/physiopathology , Adult , Aged , Aged, 80 and over , Bicarbonates/blood , Biomarkers/blood , Disease Progression , Female , Humans , Male , Middle Aged , Renal Insufficiency, Chronic/blood , Renal Insufficiency, Chronic/diagnosis , Renal Insufficiency, Chronic/physiopathology , Retrospective Studies
5.
CEN Case Rep ; 8(4): 308-310, 2019 11.
Article in English | MEDLINE | ID: mdl-31468344

ABSTRACT

The anion gap (AG) is a tool to diagnose metabolic acid-base disorders in the physiological approach to acid-base assessment. It is used to detect high AG acidosis, a type of metabolic acidosis caused by serum concentration increase in usually unmeasured anions; AG larger than the reference for it indicates the presence of high AG acidosis. This report presents a case of hyperlactatemia which was not detected as high AG acidosis possibly because of instrument error of a device in measurement of serum sodium and chloride concentrations. The case indicates that the error will make AG unable to detect high AG acidosis of any cause. Hence, upon suspicion of high AG acidosis caused by measurable anions such as lactate and ketones, it is recommended to measure their serum concentration.


Subject(s)
Acid-Base Equilibrium/physiology , Acidosis, Lactic/diagnosis , Acidosis/diagnosis , Diagnostic Errors/trends , Acidosis/blood , Acidosis, Lactic/blood , Aged , Albumins/analysis , Albumins/chemistry , Bicarbonates/blood , Bicarbonates/chemistry , Blood Chemical Analysis/instrumentation , Blood Gas Analysis/instrumentation , Chlorides/blood , Diagnostic Errors/statistics & numerical data , Electrolytes/blood , Electrolytes/chemistry , Female , Humans , Lactic Acid/blood , Lactic Acid/chemistry , Sodium/blood
7.
Kidney Blood Press Res ; 44(1): 88-93, 2019.
Article in English | MEDLINE | ID: mdl-30808847

ABSTRACT

BACKGROUND/AIMS: Compared with hemodialysis (HD), hemodiafiltration (HDF) reduces the frequency of episodes of intradialytic hypotension. Intradialytic plasma volume decrease (IPVD) induced by ultrafiltration is a leading cause of the episodes, and hemofiltration might have a preventive effect on IPVD. This study examined whether online HDF (ol-HDF) prevented IPVD compared with HD. METHODS: Online HDF of pre-dilution mode (pre-ol-HDF) and post-dilution mode (post-ol-HDF) and HD were performed in 22 patients on maintenance dialysis. In each session, IPVD was calculated by using an intradialytic change in hematocrit, and IPVD in pre-ol-HDF and post-ol-HDF was compared with that in HD in a crossover manner. RESULTS: While the ratios of intradialytic body weight loss to post-dialysis BW (IBWL/BW) in ol-HDF were generally smaller than those in HD, the levels of IPVD and IPVD/IBWL/BW were generally larger than those in HD; the IPVD levels were 0.108 ± 0.058, 0.113 ± 0.053, and 0.101 ± 0.057 (P = 0.67), and those of IPVD/IWL/BW were 2.21 ± 0.97, 2.32 ± 0.91, and 1.98 ± 1.14 (P = 0.21) in pre-ol-HDF, post-ol-HDF, and HD, respectively. CONCLUSION: Online mode hemofiltration, in either pre-dilution mode or post-dilution mode, performed in combination with hemodialysis has no preventive effect on IPVD.


Subject(s)
Hemofiltration , Plasma Volume , Aged , Aged, 80 and over , Cross-Over Studies , Female , Humans , Hypotension , Male , Middle Aged , Renal Dialysis
9.
Asian Cardiovasc Thorac Ann ; 23(5): 564-6, 2015 Jun.
Article in English | MEDLINE | ID: mdl-24585293

ABSTRACT

A 66-year-old man was transferred to our hospital with the diagnosis of a large thoracoabdominal aneurysm. Computed tomography showed thoracic vertebral erosion, suggesting a chronic contained rupture. He was hemodynamically stable with no neurological complication preoperatively. He underwent successful surgical replacement of the descending aorta. During surgery, the 6th and 7th thoracic vertebral bones adjacent to the thoracic aneurysm were found to be eroded. The postoperative course was uneventful.


Subject(s)
Aorta, Thoracic/pathology , Aortic Aneurysm, Thoracic/complications , Aortic Aneurysm, Thoracic/surgery , Aortic Rupture/pathology , Thoracic Vertebrae/diagnostic imaging , Tomography, X-Ray Computed , Aged , Aorta, Thoracic/diagnostic imaging , Aorta, Thoracic/surgery , Aortic Aneurysm, Thoracic/diagnostic imaging , Aortic Aneurysm, Thoracic/pathology , Aortic Rupture/etiology , Aortic Rupture/surgery , Humans , Male , Treatment Outcome
10.
Diagn Pathol ; 9: 117, 2014 Jun 16.
Article in English | MEDLINE | ID: mdl-24934577

ABSTRACT

Cardiac tumours are relatively rare and are difficult to diagnose merely with imaging techniques. We demonstrated an unusual case of left atrial myxoma, displaying the successful detection by positron emission tomography using 2-deoxy-2-[18 F] fluoro-D-glucose (18 F-FDG PET), correlated closely to more intense and enhanced immunoreactivity with glucose transporter-1 (GLUT-1) in a substantial number of cardiac myxoma cells. Further prospective studies are needed to validate the significance of 18 F-FDG PET findings for cardiac myxoma and the association with immunohistochemical GLUT-1 expression in its tumour cells, after collecting and investigating a larger number of surgical cases examined with both of them. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2991481941253449.


Subject(s)
Biomarkers, Tumor/analysis , Fluorodeoxyglucose F18 , Glucose Transporter Type 1/analysis , Heart Neoplasms/diagnosis , Myxoma/diagnosis , Positron-Emission Tomography , Radiopharmaceuticals , Biopsy , Female , Heart Neoplasms/chemistry , Heart Neoplasms/diagnostic imaging , Heart Neoplasms/surgery , Humans , Immunohistochemistry , Middle Aged , Myxoma/chemistry , Myxoma/diagnostic imaging , Myxoma/surgery , Predictive Value of Tests , Tomography, X-Ray Computed , Treatment Outcome
11.
Kyobu Geka ; 65(12): 1057-61, 2012 Nov.
Article in Japanese | MEDLINE | ID: mdl-23117358

ABSTRACT

Primary malignant cardiac tumors occur extremely rarely. Among these, leiomyosarcomas are exceptionally rare. We described a case of left atrial leiomyosarcoma in which surgical intervention was followed by adjuvant radiation therapy. A 74-year-old male was admitted for dyspnea. Chest X-ray showed severe pulmonary congestion. Echocardiography revealed large tumor in the left atrium. Emergency operation was performed. The tumor invaded the left atrial wall and the mitral valve, and the lesion was resected as extensively as possible. Postoperative pathologic examination confirmed leiomyosarcoma. He underwent adjuvant radiotherapy postoperatively. However, early local recurrence was recognized. He died due to sudden circulatory collapse in 8th postoperative month. As cardiac leiomyosarcomas have extremely poor prognosis, complete resection and effective postoperative adjuvant therapy are necessary.


Subject(s)
Heart Neoplasms/pathology , Leiomyosarcoma/pathology , Aged , Heart Atria , Heart Neoplasms/therapy , Humans , Leiomyosarcoma/therapy , Male
12.
Ann Thorac Surg ; 92(5): 1911-3, 2011 Nov.
Article in English | MEDLINE | ID: mdl-22051300

ABSTRACT

We describe a staged resternotomy technique using an inferior T-shaped ministernotomy for three redo cases with a retrosternal aortic arch aneurysm. To minimize the disadvantages of resternotomy during closed-chest hypothermia, an inferior T-shaped ministernotomy was performed before approaching the aneurysm. After establishment of the cardiopulmonary bypass with femoral or axillary arterial cannulation, or both, and right atrial drainage, a venting catheter was inserted into the left ventricle and core cooling was induced at 25°C. The retrosternal aneurysm was then exposed by additional superior sternotomy. Under hypotherma with antegrade cerebral perfusion, the distal side of a four-branched graft was anastomosed. During rewarming, reconstruction of the arch vessels and proximal anastomosis of the branched graft were performed. In the 3 patients operated on using this technique, there were no perioperative deaths or serious complications. This suggests that the technique can be safely performed and minimizes the disadvantages of the widely used resternotomy technique.


Subject(s)
Aortic Aneurysm, Thoracic/surgery , Sternotomy/methods , Humans , Reoperation
13.
Ann Thorac Surg ; 90(6): 1840-6, 2010 Dec.
Article in English | MEDLINE | ID: mdl-21095322

ABSTRACT

BACKGROUND: Our study aimed to demonstrate the efficacy of preoperative intraarterial computed tomographic angiography to identify the Adamkiewicz artery (AKA). We also aimed to investigate the impact of identification of the AKA on the strategy for preventing spinal cord injury. METHODS: Thirty-seven patients (24 cases of descending aortic aneurysms and 13 cases of thoracoabdominal aortic aneurysms), were studied. Average age was 63.8 years old. A pigtail catheter was inserted into the descending aorta and its tip was located immediately below the left subclavian artery. Subsequently, intraarterial computed tomographic angiography was performed and the segmental artery to the AKA was identified. Aneurysms were replaced electively with prosthetic graft in all cases. In cases where the aortic segment that supplied the AKA was cross-clamped, the identified segmental artery-AKA was selectively perfused. In these cases, the segmental artery-AKA was reconstructed with an interposition graft. RESULTS: Intraarterial computed tomographic angiography successfully identified the segmental artery-AKA in all patients. The average number of AKA observed per patient was 1.3± 0.6 AKAs. Selective perfusion of preoperatively identified segmental artery-AKAs was performed in 11 cases. The average number of reconstructed segmental arteries was 0.5 in descending aortic aneurysms and 1.7 in thoracoabdominal aortic aneurysms. Although paraparesis occurred in two patients (5%), the remaining 35 patients did not suffer spinal cord injury. CONCLUSIONS: Intraarterial computed tomographic angiography reliably identifies the segmental-AKA. Furthermore, selective perfusion of the segmental artery-AKA, based on accurate preoperative identification, might be one option for preventing intraoperative spinal cord ischemia.


Subject(s)
Angiography/methods , Aortic Aneurysm, Abdominal/surgery , Aortic Aneurysm, Thoracic/surgery , Arteries , Blood Vessel Prosthesis Implantation/standards , Practice Guidelines as Topic , Spinal Cord/blood supply , Adolescent , Adult , Aged , Aged, 80 and over , Aortic Aneurysm, Abdominal/diagnostic imaging , Aortic Aneurysm, Thoracic/diagnostic imaging , Blood Vessel Prosthesis Implantation/methods , Female , Humans , Male , Middle Aged , Preoperative Period , Prognosis , Retrospective Studies , Spinal Cord Ischemia/prevention & control , Tomography, X-Ray Computed , Young Adult
14.
Eur J Cardiothorac Surg ; 34(3): 505-9, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18585050

ABSTRACT

OBJECTIVE: To assess the use of a combination of bipolar sealing and electrosurgical coagulation for pulmonary resection. METHODS: The procedure was used in both dogs and humans. Initially, lung wedge resections were performed on six healthy, Beagle dogs using a voltage controlled electrosurgical system. The area of lung tissue to be resected was first coagulated to provide a distinct line of seal. The lung was then resected along the peripheral site of the sealing scar. Efficiency of sealing was assessed using a tracheally applied air pressure of 30cmH(2)O. The electro-cauterized tissue was compared histologically to tissue sealed by a standard stapling technique. In the clinical phase, lung resections were performed after cauterization in 17 patients. Bullectomies were performed using video-assisted thoracic surgery in 4 patients, and thoracotomic procedures in 13 (1 bullectomy, 5 wedge resections, and 7 fissure separations). RESULTS: Dogs: Tissue sealing was highly successful, without any air leakage, in all six dogs. Histologically, the clamped lesion showed tissue-fusion probably due to both the compression and thermal effects. The proximal zone adjacent to the clamped lesion revealed both collapsed alveolar spaces and fused alveolar walls. In comparison, the stapled lesions showed no tissue-fusion. Humans: There were no major complications. The median operation time was 189min, and estimated median hemorrhage volume was 67ml. Median chest drainage duration was 3 days (range: 1-7) and no patient suffered from prolonged air leakage (>7 days). CONCLUSIONS: Lung parenchymal tissue resection following bipolar sealing and electrosurgical coagulation instead of staples was efficient and simple. Furthermore, the technique reduced the use of staples, reducing the cost of the surgery.


Subject(s)
Electrocoagulation/instrumentation , Pneumonectomy/instrumentation , Adolescent , Adult , Aged , Aged, 80 and over , Animals , Blister/surgery , Dogs , Electrocoagulation/methods , Equipment Reuse , Female , Humans , Lung Neoplasms/surgery , Male , Middle Aged , Pneumonectomy/methods , Pneumothorax/surgery , Surgical Stapling , Thoracic Surgery, Video-Assisted/instrumentation , Thoracic Surgery, Video-Assisted/methods , Thoracotomy/instrumentation , Thoracotomy/methods , Young Adult
15.
Interact Cardiovasc Thorac Surg ; 7(5): 764-6, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18573845

ABSTRACT

We report the use of low-voltage, automatically regulated, electrosurgical coagulation to seal the bleeding from pulmonary arteries inadvertently during surgical intervention. Conventional electrosurgical coagulation uses high voltage, which generates intensive heat in the tissue. The heat results in carbonized eschar formation that can be easily broken by mechanical stress and lead to postoperative bleeding. SOFT COAG output automatically regulates the output voltage to a maximum of 200 Volts, preventing the generation of sparking. Thus, there is no formation of carbonized eschar. The instrument generates Joule heat alone in the tissue and the temperature rises to below boiling point, which effectively coagulates protein. Initial experiments, using a beagle model, clearly demonstrated the effectiveness and reliability of sealing both macroscopically and histopathologically. SOFT CAOG can be easily adopted both in open thoracotomy as well as in thoracoscopic procedures.


Subject(s)
Blood Loss, Surgical/prevention & control , Electrocoagulation , Hemostasis, Surgical/methods , Pulmonary Artery/injuries , Pulmonary Artery/surgery , Animals , Automation , Dogs , Electrocoagulation/instrumentation , Equipment Design , Hemostasis, Surgical/instrumentation , Models, Animal , Pneumonectomy , Pulmonary Artery/pathology , Time Factors
16.
Ther Apher Dial ; 12(1): 96-9, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18257821

ABSTRACT

Although continuous hemodiafiltration (CHDF) has been widely accepted in the management of complicated acute renal failure, the requirement for prolonged continuous systemic anticoagulation appears to be a major drawback. We herein describe the case of a patient who developed postoperative multiple organ failure and received CHDF therapy with partial blood recirculation (PBR). PBR is a mode of extracorporeal circulation used as an anticoagulation modality. The technique accelerates the blood flow rate with the goal of extending filter life, and it was performed because the filter life had been significantly shortened (10.5 +/- 5.1 h) during the CHDF process in this case. Despite increasing the dose of the anticoagulant, changing the hemofilter and changing the mode from postdilution to predilution, we did not obtain amelioration of filter life. The filter life was significantly improved (41.5 +/- 1.4 h) when we performed PBR. It is difficult to minimize the bleeding risk and maintain filter life during CHDF. Our success in prolonging the filter life during this case therefore suggests that PBR might resolve one of the main problems related to CHDF, although more study is needed to clarify the advantages of this system.


Subject(s)
Anticoagulants/administration & dosage , Hemodiafiltration/instrumentation , Hemodiafiltration/methods , Blood Flow Velocity , Equipment Design , Equipment Failure , Hemodiafiltration/adverse effects , Humans , Male , Middle Aged , Multiple Organ Failure/etiology , Multiple Organ Failure/therapy , Postoperative Complications/therapy
17.
Heart Lung Circ ; 17(3): 261-3, 2008 Jun.
Article in English | MEDLINE | ID: mdl-17416550

ABSTRACT

This report describes a rare case of the fistula between the non-coronary sinus and the right atrium (RA) after ascending aortic replacement for chronic aortic dissection. A 67-year-old lady had been suddenly suffering from severe dyspnoea with general fatigue for a couple of days. Trans-thoracic echocardiogram in the emergency room demonstrated massive shunt flow from the non-coronary sinus to the RA with remarkable dilatation of the RA, right ventricle (RV) and inferior vena cava, similar to the rupture of sinus of Valsalva (Konno-type IV). The fistula was successfully treated by partial remodelling of the aortic root in an emergency basis because of her life-threatening illness. Some remaining diseased aortic root, which may be related to initial dissection or inappropriate use of gelatin-resorcin-formalin glue at the previous ascending aortic replacement, may cause this kind of serious events. Modified aortic root remodelling method with only diseased sinus resected was successfully applied to the localised aortic root disorder.


Subject(s)
Aorta/surgery , Cardiovascular Surgical Procedures/methods , Heart Atria/pathology , Sinus of Valsalva/pathology , Vascular Fistula/surgery , Aged , Aorta/pathology , Female , Heart Atria/surgery , Heart Failure/etiology , Heart Failure/surgery , Humans , Sinus of Valsalva/surgery , Vascular Fistula/complications , Vascular Fistula/pathology
18.
J Heart Valve Dis ; 16(6): 602-7, 2007 Nov.
Article in English | MEDLINE | ID: mdl-18095507

ABSTRACT

BACKGROUND AND AIM OF THE STUDY: During off-pump coronary artery bypass grafting (CABG), mitral regurgitation (MR) has been experienced in relation to the procedures. The study aim was to evaluate the mitral valve configuration, with particular focus on annular behavior, during off-pump CABG, using cardiac endoscopy and digital 3-D ultrasound sonomicrometry. METHODS: Following implantation of six crystals of the digital 3-D ultrasound sonomicrometer around the mitral annulus, and two crystals on the epicardial base of the papillary muscles, off-pump CABG was simulated in seven beagle dogs. The heart was perfused with pellucid Krebs-Henseleit solution in situ, with controlled left ventricular end-diastolic pressure (LVEDP). The behaviors of the mitral annulus and leaflets were then observed endoscopically with only cardiac displacement, 15 min occlusion of the left anterior descending artery (LAD), or 15 min occlusion of the left circumflex artery (LCx) with cardiac displacement. Dimensions between the crystals were also recorded using digital 3-D ultrasound sonomicrometry. RESULTS: With only cardiac displacement, no MR was observed endoscopically, and no major changes occurred in annular configuration when coronary perfusion was maintained. In one dog, MR was observed only from the anterolateral site after LAD occlusion. MR from the posteromedial site was observed by occlusion of the LCx in all cases, with significant (p < 0.01) enlargement of the mitral annular dimensions. CONCLUSION: Cardiac displacement alone did not cause MR if coronary perfusion was maintained. Occlusion of the LAD rarely caused MR from the anterolateral site, whereas occlusion of the LCx normally caused MR from the posteromedial site; the posteromedial annulus was enlarged, even when the LVEDP was controlled.


Subject(s)
Coronary Artery Bypass, Off-Pump , Coronary Artery Bypass/adverse effects , Mitral Valve/diagnostic imaging , Mitral Valve/surgery , Ventricular Dysfunction, Left/physiopathology , Animals , Blood Pressure , Cardiac Volume , Dogs , Endoscopes , Fiber Optic Technology , Mitral Valve Insufficiency/diagnostic imaging , Myocardial Contraction/physiology , Ultrasonography
19.
Asian Cardiovasc Thorac Ann ; 15(3): 204-9, 2007 Jun.
Article in English | MEDLINE | ID: mdl-17540988

ABSTRACT

The cardioprotective efficacy of nicorandil in cardiac surgery was determined using a surgically relevant 4-hr cardioplegic arrest model. Each isolated rabbit heart was parabiotically blood-perfused using a modified Langendorff column. The magnitude of left ventricular developed pressure and rate of change of developed pressure over time were measured before (baseline) and after ischemia. Nicorandil was administered either pre-ischemia, post-ischemia, pre/post-ischemia, or continuously (before, during, and after ischemia). The endothelium of the coronary artery was observed by scanning electron microscopy. Serum myeloperoxidase activities were also measured. Although pretreatment with nicorandil did not affect recovery of developed pressure, administration of nicorandil after ischemia, or before and after ischemia, enhanced the recovery of developed pressure. Serum myeloperoxidase activity was decreased in the pre/post-ischemia and continuous groups. Endothelial reperfusion injury decreased in all nicorandil-treated groups. Administration of nicorandil attenuated ischemia-reperfusion injury of the myocardium and coronary endothelium while ameliorating leukocyte activation. In the event of unexpected prolonged cardioplegic arrest, administration of nicorandil, even just after declamping, may improve cardiac function. However, pre-ischemia administration alone was not helpful in the heart subjected to prolonged cardioplegic arrest.


Subject(s)
Cardiotonic Agents/pharmacology , Heart Arrest, Induced/adverse effects , Myocardial Reperfusion Injury/therapy , Nicorandil/pharmacology , Animals , Cardiotonic Agents/therapeutic use , Coronary Vessels/drug effects , Coronary Vessels/pathology , Disease Models, Animal , Endothelium, Vascular/drug effects , Endothelium, Vascular/pathology , Extracorporeal Circulation , Leukocytes/drug effects , Leukocytes/enzymology , Male , Myocardial Contraction/drug effects , Myocardial Reperfusion Injury/etiology , Myocardial Reperfusion Injury/physiopathology , Myocardial Reperfusion Injury/prevention & control , Nicorandil/therapeutic use , Peroxidase/blood , Rabbits , Time Factors , Ventricular Function, Left/drug effects , Ventricular Pressure/drug effects
20.
Eur J Cardiothorac Surg ; 29(6): 1014-9, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16675254

ABSTRACT

OBJECTIVE: The optimal orientation of a bileaflet mechanical valve for tricuspid valve replacement (TVR) has not yet been determined. The aim of this study was to use fiberoptic cardioscopy to evaluate the effect of orientation of a mechanical valve implanted in the tricuspid position on bileaflet mechanical valve behavior. METHODS: Twelve pigs (50-59 kg) underwent TVR with a St. Jude Mechanical Heart Valve (25 mm standard cuff model) after cardioplegic arrest. The mechanical valve was implanted horizontally in six pigs (Group H), and vertically in another six pigs (Group V). The heart was perfused with pellucid Krebs-Henseleit solution in situ and the mechanical valve behavior was observed with a fiberoptic endoscope during different heart rates (HRs) induced by ventricular pacing (60, 90, 120, 150 min(-1)). All images were recorded on a high-speed video system every 4 ms. The closing time lag (CTL) between the valve leaflets was calculated and compared between the two groups. RESULTS: In Group H, the lower valve leaflet tended to open incompletely and close earlier than the upper leaflet. The calculated CTL was 303+/-60 ms, 65+/-48 ms, 40+/-9 ms, and 40+/-26 ms at pacing HRs of 60, 90, 120, and 150 min(-1), respectively. In contrast to Group H, there was little difference in CTL between the right and left leaflets in Group V. The calculated CTL was 9+/-12 ms, 11+/-10 ms, 1+/-3 ms, and 6+/-7 ms at pacing HRs of 60, 90, 120, and 150 min(-1), respectively. There were significant differences in CLT between the two groups at each ventricular pacing rate (P < 0.01). CONCLUSIONS: Orientation of an implanted bileaflet valve in the tricuspid position significantly influenced leaflet motion. In a horizontal orientation, the lower valve leaflet opened incompletely and closed earlier than the upper leaflet. These results suggest that the gravity might affect leaflet motion and that bileaflet mechanical valves should be implanted vertically in TVR to prevent abnormal leaflet motion and thrombus formation.


Subject(s)
Heart Valve Prosthesis Implantation/methods , Heart Valve Prosthesis , Tricuspid Valve/surgery , Animals , Blood Pressure , Disease Models, Animal , Endoscopy , Fiber Optic Technology , Heart Rate , Image Processing, Computer-Assisted/methods , Motion , Swine , Tricuspid Valve/physiopathology
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