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PubMedDate not supplied

Aorto-caval fistulas: a review of eighteen years experience.

The operative treatment of 26 aorto-caval fistulas during the last 18 years is reviewed (24 male and two female patients; average of 65.3 year). Out of 1698 cases presenting an abdominal aortic aneurysm, 406 presented with rupture, and 26 had aorto caval fistula. In 24 cases (92.3%) it concerned an atherosclerotic aneurysm. One aneurysm with aorto-caval fistula was secondary to abdominal blunt trauma (3.8%), and one due to iatrogenic injury (3.8%). The time interval between first clinical signs of aorto-caval fistula and diagnosis, ranged from 6 hours to 2 years (average 57,3 days). Clinical presentation included congestive heart failure infive patients (11.5%), extreme leg edema in 13 (50.0%), hematuria in 2 (7.0%), renal insufficiency 2 (7.0%), and scrotal edema in six patients. Diagnosis was made by means of color duplex scan in eight patients (30.7%), CT in seven patients (27%), NMR in three patients (11.5%), and angiography in seven patients (27%). Most reliable physical sign was an abdominal bruit,present in 20 patients (77%). In ten patients (38.4%) correct diagnosis was not made prior to surgery. The operative treatment consisted of transaortic suture of the vena cava (25 pts-96.0%), and aneurysm repair. Five operative deaths occurred (19,2%), and for all of them it concerned a misdiagnosis. Cause of death was myocardial infarction (one patient-3.8%), massive bleeding (one patient-3.8%), MOF (two patients-7, 0%), and colon gangrene (one patient-3.8%). Follow-up period varied from six months to 18 years (mean 4 years and two months). Long term results showed a 96% patency rate. No postoperative lower extremity venous insufficiency nor pelvic venous hypertension was observed post-operatively.

Aged↗
PubMed1996

Prospective randomized trial of carotid endarterectomy with primary closure and patch angioplasty with saphenous vein, jugular vein, and polytetrafluoroethylene: perioperative (30-day) results.

PURPOSE: The early outcomes of carotid endarterectomy (CEA) with primary closure (PC) versus vein patch closure (saphenous vein [SVP] and jugular vein [JVP]) and polytetrafluoroethylene patch closure (PTFE-PC) were compared. METHODS: Three hundred ninety-nine CEAs were randomized into the following groups: 135 PC, 134 PTFE-PC, and 130 vein patch closure (SVP alternating with JVP). Surviving patients underwent a carotid color duplex ultrasonographic scan 1 month after surgery. Demographic characteristics were similar in all groups. RESULTS: The incidence of perioperative cerebrovascular accidents (CVAs) was 4.4% for PC, 0.8% for PTFE-PC, and 0% for vein patch closure (PC vs vein patch, p = 0.0165; PC vs all patching [vein and PTFE], p = 0.007). The perioperative CVA and reversible ischemic neurologic deficit (RIND) combined rates for all patching were superior to PC (1.5% vs 5.2%; p = 0.04). These combined rates were also superior for vein patch closure when compared with PC (0.8% vs 5.2%; p = 0.037). The mean diameter of the internal carotid artery was similar in patients who had perioperative neurologic deficits and those who did not. After 1 month of follow-up, 11.9% of the PC arteries were narrowed 50% or more in contrast to 2.3% for PTFE-PC, 3.1% for SVP, and 10.3% for JVP.

Aged↗
PubMed2000

Mitral regurgitation protects from left atrial thrombogenesis in patients with mitral valve disease and atrial fibrillation.

The aim of this study was to test the hypothesis that mitral regurgitation (MR) has a protective effect on the development of left atrial thrombus (LAT) in patients with rheumatic heart disease and atrial fibrillation (AF). The study population consisted of 48 anticoagulated patients (mean age = 57.1 +/- 10 years). Predominant mitral stenosis (MS) was present in 14 patients, predominant MR in 14, and a mechanical valve in 20. All patients underwent detailed transesophageal echocardiography. Severity of MR was based on measurements of the MR jet by color flow mapping. Patients were divided into two groups: (a) those with MR > or = 3+ (n = 12, 25%), and (b) those without significant MR (n = 36, 75%). A LAT was found in six patients (12.5%), who also had spontaneous echo contrast (SEC), while another group of 30 patients (62.5%) had SEC only. LAT and/or SEC were present in 2/12 patients (16.6%) with significant MR versus 34/36 patients (94.4%) without significant MR (P < 0.001). In addition to the absence of significant MR, left atrial diameter (LAD) > 60 mm, and severity of MS were also related to the presence of thrombus and/or SEC. Significant MR had a protective effect against thromboembolism, although this effect was abolished if LAD > 60 mm was present. In conclusion, in patients with mitral valve disease and AF, significant MR protects against LAT formation and systemic embolization. This protective effect was lost when LAD was > 60 mm.

Atrial Fibrillation↗
PubMed2005

Real-time magnetic resonance-guided endovascular repair of experimental abdominal aortic aneurysm in swine.

OBJECTIVES: This study tested the hypotheses that endografts can be visualized and navigated in vivo solely under real-time magnetic resonance imaging (rtMRI) guidance to repair experimental abdominal aortic aneurysms (AAA) in swine, and that MRI can provide immediate assessment of endograft apposition and aneurysm exclusion. BACKGROUND: Endovascular repair for AAA is limited by endoleak caused by inflow or outflow malapposition. The ability of rtMRI to image soft tissue and flow may improve on X-ray guidance of this procedure. METHODS: Infrarenal AAA was created in swine by balloon overstretch. We used one passive commercial endograft, imaged based on metal-induced MRI artifacts, and several types of homemade active endografts, incorporating MRI receiver coils (antennae). Custom interactive rtMRI features included color coding the catheter-antenna signals individually, simultaneous multislice imaging, and real-time three-dimensional rendering. RESULTS: Eleven repairs were performed solely using rtMRI, simultaneously depicting the device and soft-tissue pathology during endograft deployment. Active devices proved most useful. Intraprocedural MRI provided anatomic confirmation of stent strut apposition and functional corroboration of aneurysm exclusion and restoration of laminar flow in successful cases. In two cases, there was clear evidence of contrast accumulation in the aneurysm sac, denoting endoleak. CONCLUSIONS: Endovascular AAA repair is feasible under rtMRI guidance. Active endografts facilitate device visualization and complement the soft tissue contrast afforded by MRI for precise positioning and deployment. Magnetic resonance imaging also permits immediate post-procedural anatomic and functional evaluation of successful aneurysm exclusion.

Angioplasty↗
PubMed1996

Results of endoluminal grafting in an experimental aortic aneurysm model.

We studied the impact of an endoluminally placed stented aortic graft on the geometry of a surgically created abdominal aortic dilation (AAD) in nonatherosclerotic mongrel dogs. Patulous iliac vein patch infrarenal aortoplasty produced a fusiform AAD, doubling the aorta diameter. Lumbar and mesenteric aortic tributaries were preserved and no mural thrombus formed. AADs created in 23 dogs were endoluminally excluded through transfemoral placement of a thin-wall Dacron graft 4 +/- 2 months later. Balloon-expandable stents were used to anchor each end of the graft to the aorta. The graft was crimped radially in its body and longitudinally at its ends to provide longitudinal and radial expandability in these respective zones. Serial color duplex, angiography, and direct caliper measurements were made. Before graft placement, a 19% +/- 11% diameter growth was observed. At graft placement, flow arrest immediately occurred in the space between the graft and the AAD intima in all cases. Although microscopic recanalization of the thrombus in this space was seen at sacrifice 6 and 12 months later, no macroscopic duplex flow was imaged. A 10% +/- 11% reduction in AAD diameter was measured at 6 months (p < 0.001), with no further reduction at 12 months. Graft dimensions remained stable. No anastomotic leaks developed. AAD growth stopped during the first year after effective endoluminal exclusion in normotensive dogs despite patent side branches (< 1.5 mm internal diameter) and no mural thrombus at the time of graft placement. Whether microscopic recanalization of the thrombus that forms outside the graft has an impact after 1 year remains to be seen.

Animals↗
PubMed2003

Bond strengths of tooth-colored posts, effect of sealer, dentin adhesive, and root region.

PURPOSE: To evaluate the effect of sealer, dentin bonding agent, and root region on the push-out bond strengths of three tooth colored posts. METHODS: 24 extracted human single rooted maxillary central incisors and canines were endodontically-treated using gutta percha and Roth's 801 or AH26 sealer. Posts (Cosmopost, Fibrekor, or Parapost Fiber White) were placed using one of two adhesive systems (Parapost Cement Conditioner with Parapost Cement, or One-Step with Hi-X Post self-cure resin cement). The push-out test was performed on different sections of the root to measure bond strengths. RESULTS: Cosmopost showed significantly lower mean bond strengths than either Fibrekor or Parapost. Bond strengths of the posts in the crown section were significantly higher than those in any of the three root areas measured. Neither the eugenol-containing sealer nor the bonding agent type had any effect on bond strength. Post type and root region significantly affected bond strength while sealer type or bonding agent had no effect on bond strength.

Analysis of Variance↗
PubMed1993

Doppler-derived aortic valve gradients: imaging versus non-imaging techniques.

BACKGROUND: Quantitative Doppler echocardiography has become an established method for estimating aortic valve area in aortic stenosis, replacing cardiac catheterization as the confirmatory study. The technique is time consuming, especially when measuring the transaortic velocity, which is performed by convention. This is accomplished by interrogating multiple windows with a non-imaging probe to record the maximal velocity. To determine how the examination could be expedited, we prospectively compared aortic valve gradients measured by Pedof and duplex transducers. METHODS: One hundred eighty-two consecutive patients with native aortic valve disease, mechanical or bioprosthetic aortic valves were studied. Two technicians measured maximal transaortic valve velocities from apical, subcostal, right parasternal and suprasternal notch windows with a 2 MHz Pedof probe and from the apical window with a 3-3.5 MHz duplex probe using color flow to orient the continuous wave beam. Angle-corrected and non-angle-corrected signals were recorded. There were 109 comparisons read by two observers; intra- and inter-reader variations were 0.4% and 2.0%, respectively. RESULTS: Duplex imaging velocity gradients were consistently smaller than Pedof non-imaging measurements with a mean +/- 1 standard deviation difference between peak velocities of 0.40 +/- 0.71 meters per second (m/s) for angle-corrected, and 0.76 +/- 0.68 for non-angle-corrected signals (both p < 0.001). Technician variability accounted for some of the difference (p < 0.02). CONCLUSION: Although non-imaging and imaging methods share the apical window, the Pedof probe scans unlimited planes to locate the maximal aortic valve gradient, whereas the duplex probe is confined to the plane providing the optimal two-dimensional image. Therefore, Doppler echocardiographic estimations of aortic valve areas still require careful, time-intensive non-imaging recordings of transaortic velocities.

Aortic Valve↗
PubMedDate not supplied

Coil occlusion of the patent ductus arteriosus: lessons learned.

PURPOSE: To review the clinical outcomes of catheter-directed coil occlusion (coil occlusion) of persistently patent ductus arteriosus (PDA) at a pediatric tertiary care hospital. METHODS: A retrospective review of all patients referred to the Cardiac Catheterization Laboratory for coil occlusion at our institution was performed. Twenty-one consecutive patients (12 female) underwent coil occlusion and follow-up between May 1995 and December 1997. We undertook PDA occlusion if: (a) the PDA narrowed to less than 4 mm on echocardiogram and (b) the minimum body weight was approximately 10 kg. Standard right and retrograde left heart catheterization was performed, followed by coil occlusion. Color-flow mapping (CFM) was used intra-procedurally to confirm occlusion of the PDA with a follow-up study several weeks later. RESULTS: The median age and weight of the patients were 33 months and 13.2 kg, respectively. Fourteen patients received one coil, with six requiring a second coil and one requiring multiple coils. Initial follow-up was at a median of 2.4 months. At latest follow-up, 2 patients still have persistent flow at the ductal level. The coils were deployed without complication or embolization. CONCLUSIONS: A review of our first 21 cases demonstrated three important lessons: (1) the maximum diameter of the PDA suitable for coil occlusion is approximately 3 mm; (2) CFM must show complete obliteration of flow in the catheterization lab in order to ensure occlusion of the PDA at follow-up; and (3) the Jackson detachable system allows for precise placement of the coil, often within another coil.

Adolescent↗
PubMed2004

Remote superficial femoral artery endarterectomy and distal aSpire stenting: multicenter medium-term results.

OBJECTIVE: The purpose of this study was to examine the results of remote superficial femoral artery endarterectomy (RSFAE) in conjunction with distal aSpire stenting. METHODS: RSFAE is a minimally invasive procedure performed through a limited groin incision. Forty patients were included in the study. The indications for the procedure were claudication in 36 patients and limb salvage in 4 patients. RSFAE was performed with the MollRing Cutter device through a femoral arteriotomy. The distal atheromatous plaque was "tacked" with the aSpire stent, which is an expandable polytetrafluoroethylene-covered nitinol stent with high radial strength, yet is flexible and able to withstand compressive forces proximal to the knee joint. Before stent deployment, if the stent position is not optimal it can be wrapped down, repositioned, and re-expanded. Therefore, not only is the plaque end point tacked, but the collateral vessels may be preserved. All patients underwent follow-up examination with serial color-flow ultrasound scanning. RESULTS: The mean length of endarterectomized superficial femoral artery was 26.2 cm +/- 6.2 cm (range, 13-41 cm). The primary cumulative patency rate by means of life table analysis was 68.6% +/- 13.5% (SE) at 18 months (mean, 13.2 months; range, 1-31 months). During follow-up percutaneous transluminal balloon or stent angioplasty was necessary in 6 patients, for a primary assisted patency rate of 88.5% +/- 8.5% at 18 months. The locations of recurrent stenoses after RSFAE were evenly distributed along the endarterectomized artery. There were no deaths and one wound complication, and mean hospital length of stay was only 2.1 +/- 0.5 days. CONCLUSIONS: RSFAE with distal aSpire stenting is a safe and moderately durable procedure. If long-term patency rates are similar to those of above-knee femoropopliteal bypass graft, this procedure may prove to be a minimally invasive adjunct for the treatment of superficial femoral artery occlusive disease.

Adult↗
PubMed2005

Interventional closure with Amplatzer PFO occluder of patent foramen ovale in patients with paradoxical cerebral embolism.

Percutaneous transcatheter closure has been proposed as an alternative to surgical closure or long-term anticoagulation in patients with presumed paradoxical embolism and patent foramen ovale (PFO). We report our mid-term results of 55 consecutive symptomatic patients (mean age: 47 years, range: 20-79) who underwent percutaneous transcatheter closure of PFO after at least one event of cerebral ischemia; 16 (29%) patients had at least one transient ischemic attack and 39 (71%) patients at least one embolic stroke. Multiple embolic events had occurred in 6 (11%) patients. Percutaneous transcatheter closure was technically successful in all 55 patients (100%). For the majority of patients, an Amplatzer PFO occluder measuring 25 mm in diameter (n=49) or an Amplatzer PFO occluder measuring 35 mm in diameter (n=6) was used. Complete occlusion by color Doppler and transesophageal contrast echocardiography investigation was achieved in 96% at follow-up 3-6 months after implantation; only 2 patients had a trivial residual shunt at follow-up. Mean fluoroscopy time was 6.7 minutes (range: 1.7-47.1), and in-hospital follow-up was uneventful except for 1 patient who developed a cardiac tamponade requiring uneventful and successful needle pericardiocentesis. At a mean follow-up of 19 months (range: 3-32) no recurrent embolic neurological events was observed. Transcatheter closure of PFO with Amplatzer PFO occluder devices is a safe and effective therapy for patients with previous paradoxical embolism and aneurysmatic or nonaneurysmatic PFO. Percutaneous closure is associated with a high success rate, low incidence of hospital complications, and freedom of cerebral ischemia events.

Adult↗
PubMed2006

The evolution of the CEREC system.

BACKGROUND AND OVERVIEW: Early in 1980, the author anticipated the attraction of restoring posterior teeth with tooth-colored material. He conducted studies and developed the clinical concept of bonded ceramic inlays, at the same time raising the issue of the fast fabrication of the ceramic restorations. The author developed plans for in-office computer-aided design/computer-aided manufacturing (CAD/CAM) fabrication of ceramic restorations specifically to enable the dentist to complete one or multiple ceramic restorations chairside, in a single appointment. The initial concept comprised a small mobile CAD/CAM unit integrating a computer, keyboard, trackball, foot pedal and optoelectronic mouth camera as input devices, a monitor and a machining compartment. CEREC 3 (Sirona Dental Systems GmbH, Bensheim, Germany) divided the system into an acquisition/design unit and a separate machining unit. Three-dimensional software makes the handling illustrative and easy both in the office and in the laboratory. CONCLUSIONS: It appears that the CEREC CAD/CAM concept is becoming a significant part of dentistry. CLINICAL IMPLICATIONS: Sound knowledge of adhesive bonding and diligent planning are essential for the successful integration of CAD/CAM into clinical dental offices.

Ceramics↗
PubMed1998

[Aortic regurgitation caused by the proximal dissecting flap invagination to the left ventricle].

A 68-year-old male with sudden back pain and cardiogenic shock status transferred to our ward. Transthoracic echocardiography revealed that the abnormal round shape string was in the left ventricular outflow tract. The continuity from the staring to the aortic valve was unclear. Intimal flap could not be detected at the level of the ascending aorta. Color Doppler flow imaging showed that the severe AR jet extended into the round string. TEE showed that the intimal tear and flap was seen just above the left subclavian artery. Preoperative diagnosis was acute Stanford type A dissection and acute severe AR due to the inversion of the proximal intimal flap to the left ventricular outflow tract through the aortic valve. At operation, the proximal intimal flap was dissected circumferentially and was cut all the way around 8 cm above the aortic valve ring and was inverted to the left ventricular outflow tract. The aortic valve was preserved because of its normal character after exclusion of the proximal intimal flap. Ascending and arch replacement was carried out. Postoperative TEE and TTE slowed no findings of AR. The patient's postoperative course was uneventful. To our knowledge, this is the first reported case that severe AR caused by the proximal intimal invagination to the left ventricle.

Acute Disease↗
PubMed2000

Factors contributing to rapid wear and osteolysis in hips with modular acetabular bearings made of hylamer.

There have been several reports of osteolysis associated with rapid wear of Hylamer. A detailed analysis of retrieved implants and tissues can identify factors contributing to rapid wear and osteolysis. The mean linear wear rate of 12 liners was 0.49 mm/y, and 11 of 12 hips had progressive retroacetabular osteolysis. The average patient age was 50 years, and the mean implantation time was 50 months. All liners were sterilized by gamma irradiation in air. There was an 11-month difference in the average shelf-life of the 3 liners that were white and those that were darker in color. The volumetric wear rate of the white liners was 30% less than that of the others, suggesting a difference in the wear resistance of the liners as a function of shelf life. The mean average surface roughness (Ra) and the mean maximum surface roughness (R(max)) of the femoral heads were increased 3-fold and 50-fold compared with typical values for unused femoral heads. Evidence of 3-body wear, such as metal particles embedded in the liners, was commonly present. The pattern of backside liner deformation and burnishing was consistent with relative motion between the liner and the shell. In addition to generating Hylamer wear particles, repetitive axial motion between the liner and shell could generate fluid pressure, which transmitted through holes in the acetabular shell could cause or contribute to the development of retroacetabular osteolysis. Hylamer particles of variable shape and size, consistent with generation by several wear modes, were isolated from periprosthetic tissues.

Acetabulum↗
PubMed1992

[A case report of two mitral valve aneurysms with one perforation after two attacks of infective endocarditis].

Aneurysms of the mitral valve complicating infective endocarditis (IE) are uncommon. The patient was a 57-year-old man who was admitted to our hospital for a precise examination of heart failure. One year before, the first two-dimensional echocardiography showed an aneurysm of the anterior mitral leaflet possibly due to a previous attack of IE. Doppler color flow mapping detected a regurgitant jet from the mitral valve aneurysm into the left atrium during systole, which suggested perforation of the aneurysm, and an aortic regurgitant jet flowing against the anterior mitral leaflet. Because the patient's family refused cardiac catheter examination and surgery, we treated him in the out-patient clinic. A few weeks before his admission, he had discontinued taking diuretics because of uncomfortable urinary frequency. He gradually developed the symptoms of heart failure and entered our hospital. IE was suspected because of leucocytosis and slight fever. Two-dimensional echocardiography revealed a new aneurysm of the anterior mitral leaflet without perforation, located in the distal part of the old aneurysm. This time, his family consented to the surgical treatment. Aortic and mitral valve replacement was successfully performed. It was pathologically confirmed that the two mitral aneurysms had been caused by IE.

Aortic Valve↗
PubMed2003

Factors determining early improvement in mitral regurgitation after aortic valve replacement for aortic valve stenosis: a transthoracic and transesophageal prospective study.

BACKGROUND: Mitral regurgitation (MR) is frequently associated with aortic stenosis. Previous reports have shown that coexisting mitral insufficiency can potentially regress after aortic valve replacement. HYPOTHESIS: This study sought to assess the frequency and severity of MR before and after aortic valve replacement for aortic stenosis and to define the determinants of its postoperative evolution. METHODS: For this purpose, 30 adult patients referred for aortic valve surgery underwent pre- and postoperative transthoracic and transesophageal echocardiography and color Doppler examination. RESULTS: Mean preoperative left ventricular ejection fraction was 57 +/- 16% and remained unchanged postoperatively. Preoperative MR was usually mild to moderate and correlated with aortic stenosis severity and left ventricular systolic dysfunction. The color Doppler mitral regurgitant jet area significantly decreased during the postoperative period (p = 0.016) as left ventricular loading conditions returned to normal, suggesting an early decrease of the functional part of MR. On the other hand, the mitral regurgitant jet width at the origin remained unchanged. Statistical analysis found pulmonary artery pressure (p = 0.02) an d indexed left ventricular mass (p = 0.009) to be preoperative predictive factors of postoperative MR improvement. Predictive factors of postoperative MR severity were left atrial diameter (p = 0.02), pulmonary artery pressure (p = 0.003), and the presence of mitral calcifications (p = 0.004). CONCLUSION: In our cohort of patients with normal left venticular ejection fraction, the majority of moderate MR, associated with severe aortic stenosis, regresses early after aortic valve replacement. Mitral calcifications and/or left atrial dilation seem to be predictive factors of fixed MR.

Aged↗
PubMed1993

Quantification of asymmetric valvular regurgitant jets by color Doppler ultrasound in vitro.

Accurate quantification of regurgitant jets in natural and prosthetic heart valves has been a goal of health care workers and researchers for many years. One promising new method applies the law of conservation of momentum transfer to velocities measured by color Doppler ultrasound to calculate the flow rate in the jet. One complicating factor is that regurgitant jets from real heart valves may be highly asymmetric. The purpose of this investigation was to determine whether the accurate calculation of the flow rate in asymmetric jets imaged by color Doppler requires an asymmetric formulation of the conservation of momentum transfer, combined with a method for imaging the jet in three dimensions. Asymmetric jets issuing from narrow slits were imaged in an in vitro, steady flow system. The ultrasound transducer was rotated around the jet axis to image the jet in three dimensions. The three-dimensional imaging confirmed that jets from slits are indeed asymmetric, but become relatively axisymmetric far from the orifice. Images were analyzed by computer and the calculated flows compared to measured flows. The accuracy of an asymmetric formulation of the conservation of momentum transfer method was compared to a simpler, axisymmetric formulation. If axisymmetry was assumed in asymmetric jets, significant errors in the calculated flow rates occurred. In these cases, the calculated flow also varied widely with distance from the orifice. When asymmetry was taken into account, the errors were considerably reduced. The results suggest that, in asymmetric jets, the momentum transfer is convected around the jet axis.

Blood Flow Velocity↗
PubMed2003

Angioplasty and elective stenting of de novo versus recurrent femoropopliteal lesions: 1-year follow-up.

PURPOSE: To investigate patency rates after percutaneous transluminal angioplasty (PTA) and PTA plus elective stenting in de novo versus recurrent femoropopliteal lesions. METHODS: The data were collected from a prospective registry including 533 consecutive patients (284 men; median age 71 years, interquartile range [IQR] 72-78) with severe claudication (n=387) or critical limb ischemia (n=146) who underwent femoropopliteal percutaneous interventions during a 36-month period. PTA was used to treat 357 de novo and 99 recurrent lesions; PTA plus elective stent implantation was performed in 58 de novo and 19 recurrent lesions. Patients were followed for a median 12 months (IQR 7-14) using color duplex sonography. Rates of restenosis (>/=50%) were compared by multivariate analysis. RESULTS: Overall primary technical success was achieved in 517 (97%) patients; 31 (6%) periprocedural complications were encountered. Restenosis occurred in 213 (40%) patients after a median 6 months (IQR 4-7). Twelve-month patency after PTA was 61% in de novo and 33% in recurrent lesions (p<0.0001). Patients with recurrent lesions had a 2.3-fold increased adjusted risk for restenosis after PTA (95% confidence interval 1.7 to 3.2). Twelve-month patency after stenting was 58% in de novo and 52% in recurrent lesions (p=0.9). In patients with de novo lesions, patency rates after PTA and stent were similar (p=0.8); however, in patients with recurrent lesions, elective stenting performed better (p=0.05). CONCLUSIONS: Recurrent stenosis after prior femoropopliteal balloon angioplasty is an independent risk factor for restenosis; these lesions exhibit disappointing patency after repeated PTA. Stent implantation may improve intermediate-term results in these patients.

Aged↗
PubMed2005

Electrophysiological and histological studies of chronically implanted intrapapillary microelectrodes in rabbit eyes.

PURPOSE: To determine the safety and efficacy of transsclerally placed intrapapillary wire microelectrodes implanted chronically into the optic nerve head of rabbit eyes. METHODS: Four platinum wire microelectrodes were passed through the sclera and implanted into the optic nerve head of five rabbit eyes for 4-6 months. Color fundus photography, fluorescein angiography, electroretinograms (ERGs), and visually evoked potentials (VEPs) were used to monitor the retina. Electrically evoked potentials (EEPs) were elicited by bipolar electrical stimulation of the optic nerve axons by different combinations of the four electrodes immediately after the implantation and at 1-month intervals thereafter. The effects of the chronic implantation of the electrodes on the morphology of the optic nerve were evaluated by histological and immunohistochemical examinations at 4 and 6 months after the implantation. RESULTS: All of the electrodes remained stable in the implanted sites throughout the post-implantation period, except for one electrode that had pulled out of the optic nerve head at 1 month after implantation. No intraocular infection, inflammation, or vitreoretinal proliferation was observed in any eye. EEPs could be elicited from each pair of electrodes at all testing times. The mean threshold currents (charge densities) to evoke EEPs increased from 19.3 +/- 9.2 microA (6.0 +/- 2.9 microC/cm2) on the implantation day to 78.8 +/- 31.9 microA (24.6 +/- 10.0 microC/cm2) at 1 month after implantation, but did not change significantly thereafter. The implicit time and amplitude of the a- and b-waves of the ERGs and of P1 of the VEPs did not change significantly throughout the post-implantation period. Histological evaluation of the optic nerve head revealed slight tissue encapsulations surrounding the electrode and increased expression of glial fibrillary acidic protein near the surface of the optic nerve. CONCLUSIONS: Implantation of transscleral intrapapillary microelectrodes appears to be safe and effective. These findings indicate that the implantation of microelectrodes in the optic nerve head should be considered for an optic nerve-based prosthesis.

Animals↗