Hemodynamic assessment of replacement valves in the aortic position: is stress echocardiography necessary?
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A 63-year-old woman with a prosthetic mitral valve who developed valve thrombosis after abdominal surgical procedures is reported. She had undergone mitral valve replacement with a Sorin-Bicarbon valve 3 years previously, and was referred for an operation due to rectal cancer with anal bleeding. On admission, the patient was on oral anticoagulant therapy with warfarin, and the intensity of anticoagulation was around 40% of Thrombotest. Doppler echocardiography showed that the prosthetic mitral valve function was normal. Low anterior resection of the rectum was uneventful. Management of the perioperative anticoagulation was peformed with heparin, however, the postoperative anticoagulation using intravenous infusion of heparin was imperfectly achieved. Consequently, thrombosis of the prosthetic mitral valve occurred 8 days after the operation. Replacement of the thrombosed prosthetic valve was performed with successful results. The imperfect postoperative anticoagulation with heparin may have been the cause of the valve thrombosis. The management of perioperative anticoagulation during noncardiac operations is discussed.
Color flow Doppler provides accurate imaging and access flow volume measurement of the hemodialysis vascular access. It can readily identify subsets of patients at high risk for future thrombosis. It is noninvasive, mobile, and allows convenient clinical evaluation at the dialysis facility. In Europe, Doppler ultrasound has become the standard of care for evaluation of arteriovenous (AV) fistula dysfunction and is essential in the preoperative evaluation for access placement. It also can diagnose the arterial inflow disease that has become more prevalent in our aging, diabetic, end-stage renal disease (ESRD) population. Access management programs based on Doppler ultrasound have been highly successful and have produced outcome data as good or better than provided with other techniques. In light of its proven clinical efficacy, reimbursement and regulatory agencies should allow its appropriate inclusion into integrated access management programs. In conclusion, Doppler ultrasound should be included as a part of an integrated vascular access management program. This is supported by clinical outcome data and direct comparisons with other modalities.
This study was performed to test the usefulness of transesophageal echocardiography in the diagnosis and assessment of pathological mitral regurgitation in patients with mitral valve prostheses. Doppler color flow imaging by transesophageal echocardiography was compared to the transthoracic echocardiography and angiographic and surgical assessment. We analyzed the influence of the spatial configuration of the jet on the semiquantitative assessment of mitral regurgitation. We studied 71 patients with prostheses in mitral position which were submitted for transesophageal echocardiography examination. 51 of these patients were found to have a pathological prosthetic regurgitation that was confirmed in 21 cases by left ventriculography and in 4 during cardiac surgery. Transesophageal echocardiography Doppler color flow imaging identified a regurgitant jet in 31 patients (60.7%). There was complete agreement with the quantitative assessment of regurgitation by angiography or surgery in 36% of the cases. All patients with prosthetic insufficiency observed by angiography or during cardiac surgery were confirmed by transesophageal echocardiography. Complete agreement in grade of severity by transthoracic echocardiography was found in 84% of cases. There was a difference in grade of severity of mitral regurgitation in only 4 patients. Regurgitant jets were classified by transesophageal echocardiography color Doppler in two groups: free jets and impinging wall jets. 21 cases presented a free jet and 31 excentrically directed impinging wall jet of mitral regurgitation. There was complete agreement with hemodynamic assessment of severity in all patients with regurgitant free jets (11/11). In presence of jet wall there was understimation of mitral regurgitation in 28.5% (4/13).(ABSTRACT TRUNCATED AT 250 WORDS)
The transverse rectus abdominis musculocutaneous TRAM flap is an interesting alternative for breast reconstruction after mastectomy for cancer disease in patients who refuse mammary prosthesis and when the clinical situation allows it. There is however a risk of unpredictable partial necrosis even after rigorous surgical procedure. Some authors have proposed a Doppler evaluation before reconstruction surgery to better identify the vascular network and optimize patient selection. We performed a preliminary study in 45 patients between January 1996 and December 1999. An echo-Doppler Ultramark 9 HDI (Advanced Technology Laboratories) equipped with a high frequency (10 MHz) linear probe was used to compare blood flow and vessel caliber in the superior epigastric artery and the perforating vessels (number, localization, peak flow). The results obtained in this series could be used to determine indications for TRAM flap with or without delay procedure.
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One hundred patients with infrarenal abdominal aortic aneurysms were treated by surgery. Fifteen deaths occurred postoperatively. Eleven patients died during the follow-up of a medium period of 13 months. Three patients with a ruptured aneurysm died intraoperatively before the graft was implanted. Three patients were lost to follow-up. Sixty-four patients were examined with colour-coded Duplex sonography after surgical repair. Colour-coded Duplex sonography was able to image the aortic prostheses with the adjacent major vessels. Fifty-eight patients showed a normal prosthesis, 3 dilatation proximal of the prosthesis, 1 dilatation distal of the prosthesis, 1 mild stenosis, 1 haematoma. Colour-coded Duplex sonography imaged the intraluminal space of the prosthesis more easily than ultrasound. Colour-coded Duplex sonography was able to differentiate between intraluminal and extraluminal lesions.
BACKGROUND: Biopsy and electrical activity recordings of the corpus cavernosum are 2 new diagnostic methods for the evaluation of impotent men. We evaluated the corpus cavernosum ultrastructure and electromyography (EMG) recordings from patients with erectile dysfunction. METHODS: Twenty erectile dysfunction patients with veno-occlusive dysfunction underwent a detailed history, physical examination, biochemical tests, hormonal analysis, injection of an intracavernous vasoactive agent (60 mg papaverine-HCl), color penile Doppler ultrasonography, cavernosometry/ cavernosography and corpus cavernosum electromyography (CC-EMG). Thirteen patients underwent total vein ligation and 7 had penile prosthesis implantations. Tissue samples were obtained during surgery from both corpora cavernosa and examined by transmission electron microscopy. Control corporal tissue samples were taken from 3 cadavers. RESULTS: In 15 patients, CC-EMG recordings were 15.6 +/- 0.65 microV in the flaccid state, which decreased in 13 patients after papaverine (5.61 +/- 0.25 microV; P < 0.001). Five patients with diabetes mellitus had low amplitudes in the flaccid state (5.26 +/- 0.45 microV), which did not vary significantly after a papaverine injection (4.99 +/- 0.75 microV). The pathology of the corpus cavernosum biopsy specimens revealed a smooth muscle cell thickened basal membrane, dilated rough endoplasmic reticulum, and increased numbers of fibroblasts, but ultrastructurally normal endothelial cells lining the sinusoids. There was no difference between samples from diabetic or nondiabetic patients, or from either side of the corpora cavernosa. The only pathologic change observed in the controls was mitochondrial swelling. CONCLUSION: CC-EMG is less invasive and a valuable method in patients with erectile dysfunction, whereas no specific findings were observed from penile biopsy specimens.
Doppler echocardiography has become the method of choice for the evaluation of cardiac valve prostheses. In order to determine the reproducibility of the measurements of pressure gradient and valve surface area, 55 patients with aortic valve prostheses without clinical dysfunction and having at most a trivial regurgitation on color Doppler examination underwent a double evaluation during an average interval of 9 +/- 5 months. The maximum and mean pressure gradients were recorded and the valve surface area calculated using the continuity equation in all cases. The subaortic diameter was taken to be constant and equal to the external diameter of the prosthesis. No significant differences were found between the two evaluations of mean pressure gradient and valve surface area. The intra-patient variability was +/- 8 mmHg for the maximum pressure gradient, +/- 6 mmHg for the mean pressure gradient, +/- 0.33 cm2 for valve surface area calculated using the maximum velocities and +/- 0.44 cm2 when the velocity-time integrals were used. When expressed as a percentage, the mean coefficient of variation was 21 +/- 17% for the maximum pressure gradient, 21 +/- 18% for the mean pressure gradients, 21 +/- 15% for the valve surface area calculated using the maximum velocities and 22 +/- 14% when the ratio of velocity-time integrals was used.(ABSTRACT TRUNCATED AT 250 WORDS)
Prosthodontists are often unaware of difficulties faced by dental technicians. Likewise, dental technicians may be unaware of difficulties faced by prosthodontists. By being better educated about one another's discipline, prosthodontists and technicians can establish cooperative goals and help each other to identify significant facts and potential difficulties posed by specific materials, techniques, or stages of the work in progress. This article describes specific procedures for prosthesis fabrication and the opportunities each step provides for such cooperation. The steps include diagnostic waxing, provisional restoration, fabrication of master dies, tooth preparation, fabrication of intraoral records, treatment waxing, selection of materials, use of ceramic mucosal simulations, and color selection. If the prosthodontist and dental technician are willing to share responsibility for treatment plans, their mutual understanding can bring new insight to old problems and provide intellectual stimulation to both.
Transesophageal color flow Doppler imaging of mitral mechanical prostheses is now widely used. This method eliminates the frequent problems of acoustic shadowing and flow masking that are commonly seen with a transthoracic Doppler study of mechanical mitral prostheses. Transesophageal color flow Doppler imaging was performed postoperatively in seven patients who had received St. Jude Medical mitral prostheses (St. Jude Medical, Inc., St. Jude, Minnesota) and in six patients who received Medtronic Hall mitral valves (Medtronic, Inc., Minneapolis, Minnesota). Maximal systolic regurgitant jet length and area determinations were obtained in all patients. A comparison of maximal jet lengths and areas for each type of mechanical prosthesis demonstrated that the Medtronic Hall prostheses produced longer maximal jet lengths (p = 0.0001) and larger jet areas (p = 0.0009) than those produced by the St. Jude Medical mitral valves. Medtronic Hall prostheses produce a large centrally directed jet, whereas St. Jude Medical prostheses typically generate three smaller jets. Recognition of these differences in transesophageal color flow Doppler images in these commonly used cardiac valve prostheses is necessary to avoid misinterpretation of the normally large systolic regurgitant jet of the Medtronic Hall prosthesis as representing prosthetic dysfunction.
The application of osseointegrated fixtures to the cranial skeleton for facial prosthesis retention marks a revolutionary step in the search for the perfect soft tissue replacement. They allow present elastomer technology to be used to its greatest potential by protecting surface coloration, eliminating adhesive-induced base material degeneration, and allowing the long-term retention of fine, but weak peripheral margins. Although not all facial defect patients are candidates for this approach, the concept as applied in our present experience has proved to be a valuable replacement for available adhesive systems.
BACKGROUND: Despite advances in primary prophylaxis, venous thromboembolism still occurs in a considerable number of high-risk surgical patients. Screening with conventional ultrasound imaging to detect asymptomatic deep vein thrombosis (DVT) has been suggested as a strategy to improve management of such patients, but it is insufficiently sensitive. We evaluated the ability of color Doppler ultrasound to improve the sensitivity of compression ultrasound in the detection of asymptomatic DVT in high-risk orthopedic patients. METHODS: We prospectively evaluated bilateral compression and color Doppler ultrasound measurements of the entire leg in 204 consecutive patients who underwent elective hip or knee replacement surgery, using contrast venography as the reference test. The sensitivity, specificity, and positive predictive value of the ultrasonography tests were determined. RESULTS: The sensitivity, specificity, and positive predictive value (with 95% confidence intervals [CIs]) of compression ultrasound for the detection of proximal DVT were 60% (39%-81%), 96% (92%-99%), and 71% (48%-89%) respectively. The sensitivity, specificity, and positive predictive value (with 95% CIs) of compression ultrasound for the detection of calf vein thrombosis were 33% (18%-52%), 91% (83%-96%), and 58% (34%-80%), respectively. Color Doppler ultrasonography did not identify any additional proximal or calf vein thrombi to those detected by compression ultrasound alone. The sensitivity for all thrombi was 47% (95% CI, 34%-61%) with a positive predictive value of 65% (95% CI, 48%-79%). CONCLUSIONS: Color Doppler ultrasonography has a moderate to low accuracy for the detection of DVT in patients who have had hip and knee replacement surgery. Color Doppler ultrasonography does not increase the detection rate for asymptomatic DVT over compression ultrasound and thus cannot be recommended as a screening test in this setting.
OBJECTIVES: The aim of this study was to close muscular ventricular septal defects (MVSDs) in children, with a new device, the Amplatzer ventricular septal defect occluder (AVSDO). BACKGROUND: The design of previously used devices for transcatheter closure of MVSDs is not ideal for this purpose and their use has been limited by several drawbacks. METHODS: Six patients, aged 3 to 10 years, with MVSDs underwent transcatheter closure using the AVSDO. The device is a modified self-centering and repositionable Amplatzer device that consists of two low profile disks made of Nitinol wire mesh with a 7-mm connecting waist. The prosthesis size (connecting waist diameter) was chosen according to the measured balloon stretched VSD diameters. A 6-F or 7-F sheath was used for the delivery of the AVSDO. Fluoroscopy and transesophageal echocardiography were utilized for optimal guidance. RESULTS: The location of the defect was midmuscular in five patients and beneath the pulmonary valve in one. The balloon stretched MVSD diameter ranged from 6 to 11 mm. Device placement was successful in all patients, and complete occlusion occurred in all six patients (95% confidence interval 54.06% to 100%). Two patients developed transient complete left bundle branch block. No other complications were observed. CONCLUSIONS: This encouraging initial clinical success indicates that the AVSDO is a promising device for transcatheter closure of MVSDs in children. Further clinical trials and longer follow-up are needed before the widespread use of this technique can be recommended.
Iatrogenic vascular injuries from external fixation in orthopaedics and traumatology are frequent. Three cases of vascular injuries after the treatment with Ilizarov external fixators were treated at our institution. These include two cases of pseudoaneurysms and one case of acute ischaemia of the lower limb. Two patients became symptomatic only after removal of the fixator. In all cases, the diagnosis was made by color flow duplex sonography. All vascular injuries needed surgical repair.
The calcification potential, biostability, and immunogenic response of materials intended for long-term in vivo use, such as in heart-valve bioprostheses, are essential components of device performance. Here we explore these properties in photooxidized porcine heart valves. To study immunological sensitization, we injected tissue extracts intradermally into guinea pigs. Test and control animals received a challenge patch of the appropriate extract and were scored for dermal reactions. Neither cottonseed oil nor sodium chloride extracts of photooxidized heart-valve tissues caused any dermal inflammatory response. After implantation in the rat subcutaneous model for 90 days, the calcium content of 48-h-treated photooxidized cusp tissue [0.04 +/- 0.00 mg/g wet weight (gww)] was comparable to that of unimplanted control tissues (usually <1 mg/gww) and much lower than that of glutaraldehyde-treated controls (71 +/- 15 mg/gww). The porcine aortic wall calcium content (49 +/- 31 mg/gww) was comparable to that of glutaraldehyde-treated controls (59 +/- 8 mg/gww). Histologically, a time-dependent decrease in inflammation and vascularization with increasing photooxidation time was noted in the rat model along with an increase in the stability and organization of collagen bundles. In summary, porcine valve tissues treated by dye-mediated photooxidation were resistant to calcification, were biostable, and demonstrated a low immunogenic response, indicating potential for use in heart-valve bioprostheses.
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