(1/2752) Bileaflet mechanical prostheses for aortic valve replacement in patients younger than 65 years and 65 years of age or older: major thromboembolic and hemorrhagic complications.

OBJECTIVE: To determine major thromboembolic and hemorrhagic complications and predictive risk factors associated with aortic valve replacement (AVR), using bileaflet mechanical prostheses (CarboMedics and St. Jude Medical). DESIGN: A case series. SETTING: Cardiac surgical services at the teaching institutions of the University of British Columbia. PATIENTS AND METHODS: Patients 2 age groups who had undergone AVR between 1989 and 1994 were studied. Group 1 comprised 384 patients younger than 65 years. Group 2 comprised 215 patients 65 years of age and older. RESULTS: The linearized rates of major thromboembolism (TE) occurring after AVR were 1.54%/patient-year for group 1 and 3.32%/patient-year for group 2; the rates for major TE occurring more than 30 days after AVR were 1.13%/patient-year for group 1 and 1.55%/patient-year for group 2. The crude rates for major TE occurring within 30 days of AVR were 1.04% for group 1 and 3.72% for group 2. The death rate from major TE in group 1 was 0.31%/patient-year and in group 2 was 0.88%/patient-year. Of the major TE events occurring within 30 days, 100% of patients in both age groups were inadequately anticoagulated at the time of the event, and for events occurring more than 30 days after AVR, 45% in group 1 and 57% in group 2 were inadequately anticoagulated (INR less than 2.0). The overall linearized rates of major hemorrhage were 1.54%/patient-year for group 1 and 2.21%/patient-year for group 2. There were no cases of prosthesis thrombosis in either group. The mean (and standard error) overall freedom from major TE for group 1 patients at 5 years was 95.6% (1.4%) and with exclusion of early events was 96.7% (1.3%); for group 2 patients the rates were 90.0% (3.2%) and 93.7% (3.0%), respectively. The mean (and SE) overall freedom from major and fatal TE and hemorrhage for group 1 patients was 90.1% (2.3%) and with exclusion of early events was 91.2% (2.3%); for group 2 patients the rates were 87.9% (3.1%) and 92.5% (2.9%), respectively. The 5-year rate for freedom from valve-related death for group 1 patients was 96.3% (2.1%) and for group 2 patients was 97.2% (1.2%). CONCLUSION: The thromboembolic and hemorrhagic complications after AVR with bileaflet mechanical prostheses occur more frequently and result in more deaths in patients 65 years of age and older than in patients years younger than 65 years.  (+info)

(2/2752) Evaluation of the allograft-prosthesis composite technique for proximal femoral reconstruction after resection of a primary bone tumour.

OBJECTIVE: To evaluate clinical and functional outcomes resulting from the allograft-composite technique used for proximal femoral osteoarticular reconstruction in patients who had limb salvage surgery for primary bone tumours. DESIGN: A retrospective review of a prospectively gathered database to provide a descriptive study. SETTING: A tertiary care musculoskeletal oncology unit in a university hospital. PATIENTS AND INTERVENTIONS: Patients treated between 1987 and 1993 were eligible for inclusion in this study if they met the following criteria: they were treated surgically for a primary malignant bone tumour; and a proximal femoral allograft-implant composite technique was used for the reconstruction. MAIN OUTCOME MEASURES: Major postoperative complications with emphasis on mechanical complications in the reconstructive composite implant. Functional outcome in a subset of patients using the 1987 and 1994 versions of the Musculoskeletal Tumor Society instrument, the Short-Form-36 and the Toronto Extremity Salvage Score. RESULTS: There were 5 mechanical and 2 infectious complications requiring surgical intervention. Functional scores were generally low. CONCLUSIONS: Our results suggest that the perceived benefits of the composite technique may accrue only to a few patients, partly owing to the risk of mechanical complications. Although these can be reduced by avoiding the use of cement in the host femur, the generally poor functional outcomes suggest that this technique needs to be studied further in this group of patients and compared with other reconstructive techniques, particularly the prosthetic implant.  (+info)

(3/2752) Factors influencing the development of vein-graft stenosis and their significance for clinical management.

OBJECTIVES: To assess the influence of clinical and graft factors on the development of stenotic lesions. In addition the implications of any significant correlation for duplex surveillance schedules or surgical bypass techniques was examined. PATIENTS AND METHODS: In a prospective three centre study, preoperative and peroperative data on 300 infrainguinal autologous vein grafts was analysed. All grafts were monitored by a strict duplex surveillance program and all received an angiogram in the first postoperative year. A revision was only performed if there was evidence of a stenosis of 70% diameter reduction or greater on the angiogram. RESULTS: The minimum graft diameter was the only factor correlated significantly with the development of a significant graft stenosis (PSV-ratio > or = 2.5) during follow-up (p = 0.002). Factors that correlated with the development of event-causing graft stenosis, associated with revision or occlusion, were minimal graft diameter (p = 0.001), the use of a venovenous anastomosis (p = 0.005) and length of the graft (p = 0.025). Multivariate regression analysis revealed that the minimal graft diameter was the only independent factor that significantly correlated with an event-causing graft stenosis (p = 0.009). The stenosis-free rates for grafts with a minimal diameter < 3.5 mm, between 3.5-4.5 and > or = 4.5 mm were 40%, 58% and 75%, respectively (p = < 0.05). Composite vein and arm-vein grafts with minimal diameters > or = 3.5 mm were compared with grafts which consisted of a single uninterrupted greater saphenous vein with a minimal diameter of < 3.5 mm. One-year secondary patency rates in these categories were of 94% and 76%, respectively (p = 0.03). CONCLUSIONS: A minimal graft diameter < 3.5 mm was the only factor that significantly correlated with the development of a graft-stenosis. However, veins with larger diameters may still develop stenotic lesions. Composite vein and arm-vein grafts should be used rather than uninterrupted small caliber saphenous veins.  (+info)

(4/2752) Frame dislocation of body middle rings in endovascular stent tube grafts.

OBJECTIVES: To understand the cause, and propose a mechanism for frame dislocation in endovascular grafts. MATERIALS AND METHODS: Five tube grafts were explanted due to secondary distal leakage 15-21 months after operation. One bifurcated graft was removed during emergency operation after aortic rupture caused by secondary leakage. A second bifurcated graft was harvested from a patient with thrombotic occlusion of one limb, who died after transurethral prostatic resection. The inside of the grafts were examined endoscopically. The stent was inspected after removal of the fabric, broken ligatures were counted and examined by scanning electron microscopy. The fabric strength was tested by probe puncture. RESULTS: We found 17-44% of the stent ligatures of the body middle rings to be loose. The knots were intact. Degradation of the polyester textile was not observed. CONCLUSIONS: Continuous movements in the grafted aorta and blood pressure impose permanent stress to the stent frame and the polyester fabric resulting in morphological changes in the body middle ring of grafts. The clinical implications of the suture breakages are unknown although they may be related to distal secondary leakage in tube grafts.  (+info)

(5/2752) Experimental assessment of proximal stent-graft (InterVascular) fixation in human cadaveric infrarenal aortas.

OBJECTIVES: This paper investigates the radial deformation load of an aortic endoluminal prosthesis and determines the longitudinal load required to cause migration in a human cadaveric aorta of the endoprosthesis. DESIGN AND METHODS: The endovascular prosthesis under investigation was a 24 mm diameter, nitinol, self-expanding aortoaortic device (InterVascular, Clearwater, Florida, U.S.A.). Initially, a motorised digital force gauge developed an incremental load which was applied to the ends of five stent-grafts, to a maximum of 10 mm (42%) compression. Secondly, using a simple bench model, each ends of four stent-grafts were deployed into 10 cadaveric experimental aneurysm necks and a longitudinal load applied to effect distraction. RESULTS: Increasing load produced increasing percentage deformation of the stent-grafts. The mean longitudinal distraction load for an aneurysm neck of 20 mm was 409 g (200-480 g), for 15 mm was 277 g (130-410 g) and for 10 mm was 218 g (130-340 g). The aneurysm diameter and aortic calcification had p values of 0.002 and 0.047, respectively, while the p value for aneurysm neck length was less than 0.00001. CONCLUSIONS: These results suggest that there is a theoretical advantage of oversizing an aortic prosthesis and that sufficient anchorage is achieved in an aortic neck of 10 mm to prevent migration when fully deployed.  (+info)

(6/2752) Fate of endoleaks after endoluminal repair of abdominal aortic aneurysms with the EVT device.

OBJECTIVE: we aim to describe our medium-term follow-up of 20 patients with an endoleak following repair of their abdominal aortic aneurysms (AAA) using the Endovascular Technologies (EVT) device. DESIGN: the experience of one centre in a prospective multicentre phase II trial. MATERIALS AND METHODS: 55 patients with an endovascular repair of their AAA and at least 6 months>> follow-up were reviewed. Intraoperative angiograms, next day duplex scans and computed tomography (CT) images were used to detect endoleaks. Follow-up with CT and duplex was performed at 3, 6, 12 and 24 months. Persistent endoleaks at 6 months were evaluated by angiography and treated by endovascular coiling. RESULTS: there were three immediate conversions to open procedures. Twenty of 52 (38%) patients had an endoleak identified initially. One patient died from a myocardial infarction and three were not evident any longer by discharge CT. Sixteen endoleaks (31%) were present at discharge. Nine resolved spontaneously by 3-6 months and seven were still persistent at 6 months (14%). Six patients underwent coiling of their leak, all with successful radiographic seal after 1-3 sessions. CONCLUSIONS: endoleaks are frequent after endovascular AAA repair, but the majority close spontaneously. Coiling of the leaks and radiographic seal can be achieved in all cases still persistent at 6 months. Whether this method is clinically effective awaits further follow-up.  (+info)

(7/2752) Management of a rare complication of endovascular treatment of direct carotid cavernous fistula.

A 30-year-old woman with direct carotid cavernous fistula underwent endovascular treatment with detachable balloons via a transarterial route. The patient returned with diplopia 1 year after therapy. On cranial MR imaging, one of the balloons was detected in the proximal portion of the superior ophthalmic vein and was deflated percutaneously with a 22-gauge Chiba needle under CT guidance. The patient's symptoms resolved after balloon deflation. This case report presents a unique complication of endovascular treatment of direct carotid cavernous fistula and its management.  (+info)

(8/2752) Is there a need for routine testing of ICD defibrillation capacity? Results from more than 1000 studies.

AIMS: Benefits and complications of postoperative implantable cardioverter-defibrillator tests are controversial matters. This study sought to assess the necessity of defibrillation function tests after implantation. METHODS AND RESULTS: We retrospectively analysed 1007 implantable cardioverter-defibrillator tests in 587 systems and 556 patients. Nine hundred and thirty implantable cardioverter-defibrillator tests (89.4%) were routinely performed. Seventy-one tests (7%) were performed after a change in the antiarrhythmic drug regimen and six tests (0.60%) because of a suspected dysfunction of the implantable cardioverter-defibrillator. During routine tests, four systems (0.4%) failed to defibrillate the patient. However, in all but one test, abnormalities of the system had been observed before the test. After the addition of antiarrhythmic drugs, two of 71 implantable cardioverter-defibrillator systems (2.8%) failed to defibrillate the patient. One of six systems tested due to a suspected dysfunction failed to defibrillate the patient. During 16 tests (1.6%), complications occurred. CONCLUSIONS: Our experience demonstrates that postoperative tests of the defibrillation function of implantable cardioverter-defibrillators rarely reveal dysfunctions. As testing is unpleasant for the patient and not free of complications, tests might be restricted to those patients in whom a dysfunction is suspected and to those patients in whom class I or class III antiarrhythmic drugs have been added to the antiarrhythmic drug regimen.  (+info)