Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Prosthesis Coloring”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,675 records · Page 93Linked to original sources
PubMed2003

[Myocardial protective effect of L-carnitine in cardioplegia solution on patients undergoing heart valve replacement operation].

OBJECTIVE: To investigate the myocardial protective effect of L-carnitine as an ingredient of cardiac arresting solution in the process of heart valve replacement operation. METHODS: 69 cases undergoing heart valve replacement with cardiopulmonary bypass (CPB), 47 males and 22 females, aged 48.17 +/- 14.22 (16 approximately 74 years), were divided into 3 groups: test group I (n = 22, 12 g/L L-carnitine was put in the St. Thomas II cold crystal cardiac arresting liquid), test group II (n = 24, 6 g/L L-carnitine was put in the St. Thomas II cold crystal cardiac arresting liquid), and control group (n = 23, no L-carnitine was put in the St. Thomas II cold crystal cardiac arresting liquid). Before operation, 20 minutes after the beginning of shunt, after the finish of shunt, and 8 hours, one day, 3 days, and 7 days after operation venous blood was drawn to test the serum cardial tropnin I (cTnI), aspartate transaminase, lactate dehydrogenase, creatine kinase (CK) and CK-MB isozyme. Heart color ultrasonography was conducted to test the cardiac index (CI) and left heart ejecting fraction (EF) one day before operation and 7 days after operation. Before shunt and by the end of intracardiac procedure a bit of myocardial tissue was taken to undergo electron microscopy. The amounts of vaso-active drugs, such as dopamine and dobutamine, used postoperatively, and the postoperative cardiac auto-rebeating rate were recorded. RESULTS: The Amounts of vaso-active drugs used after operation was 329 +/- 54 mg in the test group I and 339 +/- 47 mg in the test group II, both significantly less than in the control group (669 +/- 56 mg, both P < 0.01) without a significant difference between the 2 test groups. Since the end of CPB to 3 days after operation, the serum levels of cTnI, aspartate transaminase, lactate dehydrogenase, CK and CK-MB isozyme were significantly lower in the 2 test groups than in the control group (P < 0.05 or P < 0.01). The serum level of cTnI in test group I was significantly lower than in the test group II (5.71 +/- 1.14 ng/ml vs 7.87 +/- 1.89 ng/ml 1 day postoperatively (P < 0.05), and 5.01 +/- 0.89 ng/ml vs 7.53 +/- 1.43 ng/ml 3 days postoperatively (P < 0.05). The postoperative cardiac auto-rebeating rate was 87.9% in the test group I and 74.3% in the test group II, both significantly higher than that in the control group (45.7%, P < 0.05 and P < 0.01). Heart color ultrasonogram showed that 7 days postoperatively the CI index was 2.86 +/- 0.55 and 2.74 +/- 0.56 in the 2 test groups, significantly higher than that in the control group (2.11 +/- 0.35, both P < 0.05), and the left heart EF were 64.3 +/- 8.6 and 59.1 +/- 6.7 in the 2 test groups, both significantly higher than that in the control group (51.7 +/- 4.9, both P < 0.05). Electron microscopy showed only slight swelling of mitochondria in the cardial cell and the myocardial fiber was intact by the end of operation in the 2 test groups without significant difference between these 2 groups, however, in the control group swelling of mitochondria with vesicle formation, fissure of part of mitochondrial ridges, and disappearance of glycogen particles were found. CONCLUSION: Antegrade coronary perfusion of L-carnitine has a good protective effect on myocardium and is worth spreading for heart valve replacement patients with cardiopulmonary bypass.

Adolescent↗
PubMed1993

[Left intraventricular dynamic gradients in the follow-up of aortic valve replacement: an echo-Doppler study].

The possibility of an intraventricular pressure gradient in patients with aortic stenosis is well known: this entity is associated with a high risk of postoperative complications. The authors carried out a Doppler echocardiographic study of flow in the left ventricle in 51 patients who had recently undergone valve replacement for severe aortic stenosis (valve area < 0.75 cm2). Before surgery, only one patient had significant acceleration of intraventricular systolic flow attaining 3.8 m/s (maximum pressure gradient of 60 mmHg). After surgery, maximum intraventricular systolic velocities of over 2.5 m/s with a typical end systolic peak were observed in 8 patients under basal conditions (gradients of 30 to 115 mmHg), and in 7 others after inhalation of amyl nitrite. Pulsed spectral and color Doppler flow mapping showed that the highest velocities were located at the mitral papillary muscle level. In addition, these patients had significant reduction in cavity size. Only one patient had systolic anterior motion of the anterior mitral leaflet with septal contact. Left ventricular dimensions were measured by TM echocardiography. High intraventricular velocities seemed to be significantly related to the smallest ventricular dimensions, the thickest ventricular walls and the smallest preoperative aortic valve surface area. The highest intraventricular pressure gradients-disappeared with betablocker therapy (4 cases), after correction of hypovolemia (1 case), after drainage of large pericardial effusions (2 cases) or spontaneously (1 case). This study confirms the relatively high prevalence of dynamic intraventricular gradients after surgical cure of aortic stenosis and the value of Doppler echocardiography for the avoidance of certain drugs (inotropic agents, vasodilators, diuretics), which could aggravate the hemodynamic abnormality.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Forecasting thrombosis of vascular access with Doppler color flow imaging.

A noninvasive technique, color Doppler flow imaging, was used to study the predictive value for future episodes of thrombosis in vascular access (polytetrafluoroethylene [PTFE] grafts and radial-cephalic fistulae) in a series of chronic hemodialysis patients. Patients with grafts were classified into three groups based on maximum constriction of the vascular access diameter: narrowing of greater than 50% (group I), narrowing of 30% to 50% (group II), and no narrowing or narrowing less than 30% (group III). More than half of the patients in group I suffered vascular access thrombosis within 6 months, while only 9% to 13% of patients in groups II and III had episodes of thrombosis during the same time interval. Decreased access volume flow (AVF) also correlated with episodes of thrombosis in these patients. No correlation could be demonstrated between recirculation and future thrombosis. No patient with a fistula had narrowing greater than 30% and none had vascular access thrombosis during the 6-month follow-up.

Arteriovenous Shunt, Surgical↗
PubMed2000

[Percutaneous closure of patent ductus arteriosus with the Amplatzer duct occluder].

BACKGROUND AND METHODS: Percutaneous closure of a moderate-to-large sized patent ductus arteriosus using multiple coils or a Rashkind double-umbrella may be technically demanding and raises a significant rate of embolization and residual shunting. This is why we tried a new self-expandable device called Amplatzer Duct Occluder to close transvenously large ductuses in eighteen patients at a median age of 2.8 years (range: 0.7 to 34). They had a patent ductus arteriosus with a minimal diameter > 3 mm (mean: 5 +/- 2 mm). The device had a mean diameter of 9 +/- 2 mm and was delivered through a 6F venous sheath. Aortography was done 5 to 10 minutes after the release and follow-up evaluation was performed with color Doppler echocardiography within 24 h, 1 and 3 to 6 months after the procedure. RESULTS: Placement was successful in all but the first patient (95%). Complete closure was achieved immediately in 4/17 patients (24%) and in 13/17 (76%) 24 h later. Two patients were lost for follow-up. Complete closure was confirmed in 14 of the 15 (93%) reviewed patients at 1 and 3 months. In all patients with a ductal diameter < or = 7.5 mm the closure was complete at 1 month. Embolization occurred in one patient with a 9.7 mm duct and surgery was undertaken. A mild and transient hematuria was observed in one patient. No pulmonary artery stenosis nor aortic obstruction were observed on follow-up. CONCLUSION: The Amplatzer Duct Occluder device offers a safe and effective option to treat patients with a ductus arteriosus which minimal diameter is up to 7.5 mm.

Adolescent↗
PubMedDate not supplied

Cross-sectional left ventricular outflow tract velocities before and after aortic valve replacement: a comparative study with two-dimensional Doppler ultrasound.

To assess whether aortic valve replacement (AVR) results in changes in the flow velocity distribution in the left ventricular outflow tract (LVOT), 10 patients undergoing AVR for aortic stenosis were studied. By extracting velocity information from color flow maps as digital data, instantaneous cross-sectional velocity profiles were constructed. Velocity profiles obtained 1 to 3 days before AVR were compared with recordings made 3 months later. The LVOT velocity profiles were variably skewed both before and after surgery, and no systematic or uniform changes could be detected after AVR. The highest velocities were most often localized in the region from the center of the outflow tract diameter toward the septum both before and after surgery. At the time of peak flow the ratio of the maximum to the cross-sectional mean velocity was 1.38 +/- 0.13 before and 1.39 +/- 0.08 after AVR (NS), and the ratio of the maximum to the mean velocity time integral was 1.47 +/- 0.10 before and 1.56 +/- 0.10 after (NS). We conclude that AVR in patients with aortic stenosis does not result in a change in LVOT velocity profiles that will influence stroke volume estimates with the Doppler technique.

Aged↗
PubMedDate not supplied

Long-term endothelial cell loss following phacoemulsification through a temporal clear corneal incision.

PURPOSE: To evaluate central endothelial cell loss (ECL) following clear corneal cataract surgery using two different incision sizes and the effect of ultrasound time (UST) and power on postoperative ECL and various cell parameters. METHODS: Fifty-eight patients had phacoemulsification through temporal, two-step clear corneal tunnel incisions. In Group A (n = 28), a one-piece, plate-haptic foldable silicone intraocular lens (IOL) was implanted through a 3.5 mm sutureless incision. In Group B (n = 30), a poly(methyl methacrylate) IOL was implanted through a 5.0 mm incision with one radial suture. The central endothelial cell counts were recorded preoperatively and postoperatively at 2 to 5 days, after 6 months, and after 1 year. Color-coded, computer-assisted specular microscopy was used for special cell analysis after 1 year. RESULTS: Collective data showed an ECL of 7.9 +/- 4.1% (mean +/- standard deviation) at 2 to 5 days postoperatively, 6.7 +/- 2.9% after 6 months, and 7.3 +/- 3.3% after 1 year. A direct linear relationship was found between ECL and UST and power: ECL increased as UST and power increased. After 1 year, ECL in Group A was 4.2% with UST < or = 11/2 minutes, 6.7% with UST > 11/2 to 21/2 min, and 9.6% with UST > 21/2 to 31/2 min; in Group B it was 6.0%, 7.5%, and 11.4%, respectively. Specular microscopy showed normal, age-related cell parameters 1 year postoperatively. CONCLUSIONS: Phacoemulsification with 3.5 mm clear corneal incisions produced slightly less ECL (6.7%) than phacoemulsification with 5.0 mm incisions (7.9%). Total ECL of 7.3% at 1 year postoperatively compared favorably with ECL rates of other cataract extraction methods.

Aged↗
PubMedDate not supplied

Aneurysms of the lower limbs: evaluation and management.

In order to evaluate the results of the conservative follow up vs surgical management of infra-inguinal aneurysms, a retrospective review of 23 patients with 28 peripheral aneurysms of the lower limbs was undertaken. Among them, common femoral (5 cases) and popliteal (16 cases) aneurysms were most frequent; superficial femoral (1) and tibial (1) aneurysms were isolated; 5 patients had bilateral aneurysms. The majority of symptomatic aneurysms presented local discomfort (4), acute (4) or chronic (8) ischaemia. Symptoms of nerve (2) or view (1) compression were less common. Duplex or Color-Doppler Scanning, angio-TC and MR confirmed the clinical diagnosis; arteriography demonstrated the number of patent distal vessels. Nine arterial aneurysms were kept under clinical and ultrasonographic observation; three patients were submitted to delayed surgical repair; a major amputation was required and two of these died of cardiac diseases. In the remaining sixteen cases, early elective surgical repair was performed, with resection or ligation of aneurysms. Two cases of acute limb ischaemia were submitted to successful limb-salvage procedures. A primary amputation was necessary in a case with irreversible ischaemia; a lumbar sympathectomy was performed in a patient with a poor run-off. Dacron (5 cases), PTFE (5 cases) or autologous saphenous vein (11 cases) grafts were used. No post-operative complications or limb-loss occurred. Three patients died of myocardial infarction during the follow up period (mean 28 months). Authors' results suggest that early surgical repair of peripheral aneurysms of the lower limbs is the safest and most effective management.

Aged↗
PubMed1990

Graft geometry and venous intimal-medial hyperplasia in arteriovenous loop grafts.

This study explores graft geometry and hemodynamics in a reproducible canine arteriovenous loop graft model of intimal-medial hyperplasia. Untapered 6 mm diameter polytetrafluoroethylene grafts (n = 10) were paired with 4 to 7 mm taper (n = 5) or 7 to 4 mm taper (n = 5) grafts for a 12-week period. Several hemodynamic variables were assessed at multiple locations, and venous intimal-medial thickness was measured at locations corresponding to the hemodynamic measurements. Color Doppler imaging demonstrated energy transfer out of the vessel in the form of perivascular tissue vibration. This was quantitated by the distance required for Doppler signal attenuation or volume of the detected vibration signal. Differences among graft types were noted for pressure, flow velocity, tissue vibration, and venous intimal-medial thickness. Hyperplasia was significantly decreased in 4 to 7 mm taper grafts. Stepwise deletion regression indicated volume of the vibration signal had a better correlation with venous intimal-medial thickness than any other variable (r 0.9, p less than 0.001). We conclude that graft geometry can have a significant impact on hemodynamic factors and venous intimal-medial hyperplasia in arteriovenous loop grafts. Flow disturbances appear to cause energy transfer through the vessel wall and into perivascular tissue. Kinetic energy transfer in the form of perivascular tissue vibration was quantitated in vivo and correlates strongly with venous intimal-medial thickness.

Animals↗
PubMed2003

Effect of a closure device on complication rates in high-local-risk patients: results of a randomized multicenter trial.

Clinical trials have shown that coronary stenting is associated with a high level of complications at the access site. Arterial sealing devices have proven their efficacy in obtaining immediate hemostasis after sheath removal, in allowing early ambulation, and in improving patient comfort. However, there is no report showing a reduction of local complications related to their use. The purpose of this multicenter study was to compare randomly the efficacy of Angio-Seal versus compression methods of hemostasis in reducing the rate of access site complications after coronary angioplasty in 612 selected patients with higher risk of local events satisfying at least one of the following high-risk criteria: age > 70, previous puncture at the same site, history of hypertension, treatment with ticlopidine at least 2 days before the procedure, use of abciximab, 8 Fr access, prolonged heparin treatment after the angioplasty, and use of lytics if fibrinogen > 1 g/l. Group A (n = 306) had immediate sheath removal, Angio-Seal implantation, and cessation of bed rest 4 hr after the intervention. Group B (n = 306) had sheath removal according to local practice and cessation of bed rest 6-18 hr after the hemostasis procedure, also according to local practice. Clinical follow-up was done at 1 hr, 4 hr, 24 hr, discharge, and 7 days and a systematic color flow duplex sonography was performed to confirm diagnosis of access site complication. In group A, device deployment and immediate hemostasis were obtained in, respectively, 96.8% and 87% of patients. Time to hemostasis was shorter in group A: 5 vs. 52 min (P < 0.001). Cessation of bed rest was dramatically reduced in group A (438 +/- 450 min) vs. group B (952 +/- 308 min; P < 0.001). The cumulative rate of complications, using a composite primary endpoint, at 7 days was significantly different between the two groups: 5.9% of group A patients and 18% of group B patients (P < 0.001). This difference was mainly due to the dramatic reduction of prolonged bleeding in group A patients. Angio-Seal device use in high-local-risk patients allows immediate sheath removal and hemostasis with a reduction of local event rate despite a higher level of anticoagulation, compared to regular compression techniques, directly related to a dramatic decrease of prolonged bleeding.

Adult↗
PubMed2006

Anastomotic pseudoaneurysms: our experience with 49 cases.

We investigated the factors implicated in the pathogenesis of anastomotic aneurysm formation and the postoperative course of patients with such a complication. Forty-five patients with 49 anastomotic aneurysms were diagnosed and treated in two vascular surgery departments in Athens, Greece, during an 8-year period. Emergent complications occurred in 15 cases, rupture in 11, and thromboembolic episodes in another four. Preoperative diagnostic workup in the remaining elective cases (n = 34) included color duplex scan, computed tomographic scan, and angiography. All patients underwent operation, and cultures were obtained during the surgical procedures. Histological examination of the host artery wall adjacent to the aneurysm was also performed. Aortobifemoral bypass was the original operation performed in the majority of cases (71%), and the femoral anastomosis was the most frequent site involved (85.7%). Emergent procedures were associated with increased mortality (46.6%), whereas elective operation resulted in high patency rates and no mortality. In an attempt to isolate predisposing factors that contributed to aneurysm formation, we concluded that the etiology was multifactorial in approximately one-third of the cases and degenerative host artery disease was the main cause (40%). Arterial degeneration is the leading cause of anastomotic aneurysm formation, and emergency arterial reconstruction in cases of aneurysm complication is associated with a poor prognosis.

Aged↗
PubMed2005

Use of short PTFE segments (<6 cm) compares favorably with pure autologous repair in failing or thrombosed native arteriovenous fistulas.

OBJECTIVE: The re-establishment of patency in a stenosed or thrombosed native arteriovenous fistula (AVF) is fundamental to regaining adequate hemodialysis through the same cannulable vein. Many surgeons have been reluctant to use even small segments of synthetic grafts in AVF revisions because of a perception that these would lead to poor results; however, studies comparing various treatment options are scarce. This study compared the use of short (<6 cm) polytetrafluoroethylene (PTFE) segments with pure autologous repair in stenosed or thrombosed native fistulas. METHODS: The cumulative postintervention primary patency rates of two groups of hemodialysis patients receiving different surgical revision operations of their vascular accesses were prospectively compared. Group I (n = 30) comprised patients who presented with stenosed or thrombosed native fistulas and received short (2 to 6 cm) interposition PTFE grafts placed after the stenosed or thrombosed outflow vein segment was resected. These short PTFE grafts were not used for cannulation. Group II (n = 29) comprised patients who presented with dysfunctional or failed AVFs and underwent various types of pure autogenous corrections. AVF dysfunction or thrombosis was detected with clinical examination and color duplex ultrasound scanning. In all cases, on-table arteriography-fistulography was performed before surgical repair. Access adequacy was assessed in all patients postoperatively after the first puncture and every month thereafter (mean follow up 16.7 months). RESULTS: No statistically significant difference in patency was observed between the two groups. Postintervention cumulative patencies were 100%, 88%, and 82% for group I and 90%, 82%, and 71% for group II at 6, 12, and 18 months, respectively ( P = .8). CONCLUSIONS: Short (<6 cm) interposition PTFE segments used for the revision of failing or failed AVFs compare favorably to purely native repair and do not alter the autologous behavior of the initial access. These short PTFE revisions resulted in satisfactory midterm primary patency without further consumption of the venous capital by harvesting segments of vein from other locations and without compromising more proximal access sites. This practice is recommended and is justified as part of an aggressive access salvage policy addressed by many authors so far.

Aged↗
PubMed2005

Primary patency of long-segment self-expanding nitinol stents in the femoropopliteal arteries.

PURPOSE: To report a retrospective cohort study of nitinol stent implantation in patients at high risk for restenosis owing to long-segment (> or =10 cm) femoropopliteal disease. METHODS: Sixty-five consecutive patients with peripheral artery disease underwent long-segment (> or =10 cm) femoropopliteal stent implantation using self-expanding nitinol stents after initial failure of plain balloon angioplasty (i.e., residual stenosis >30% or a flow-limiting dissection). Patients were followed for first occurrence of in-stent restenosis, defined as a >50% lumen diameter reduction by color-coded duplex sonography, with angiographic confirmation. RESULTS: Cumulative median length of the stented segments was 16 cm (interquartile range [IQR] 12-25, absolute range 10-40) using up to 5 overlapping stents. During the median 8-month follow-up (IQR 6-11), no early thrombotic reocclusions occurred within 30 days, but 26 (40%) patients developed an in-stent restenosis. Cumulative freedom from restenosis at 6 and 12 months was 79% and 54% overall, respectively; at the same time periods, the rates were 84% and 71% in nondiabetic patients (n=41) versus 68% and 22% in diabetics (n=24) (adjusted hazard ratio 3.8, p=0.01). Cumulative stent length and number of implanted stents were not associated with restenosis. CONCLUSION: Midterm restenosis after long-segment femoropopliteal stenting using self-expanding nitinol stents remains a major problem, particularly in patients with diabetes mellitus. The midterm results in nondiabetics are encouraging.

Aged↗
PubMed1999

Tricuspid regurgitation late after mitral valve replacement: clinical and echocardiographic evaluation.

BACKGROUND AND AIM OF THE STUDY: Significant tricuspid regurgitation (TR) can contribute to increased morbidity and mortality in patients after mitral valve replacement (MVR), both in the immediate and late postoperative period. The aim of this study was to evaluate the prevalence and the clinical importance of TR late after MVR, as assessed both clinically and echocardiographically. METHODS: The study group comprised 65 patients (39 women, 26 men; mean age 61+/-12 years) with rheumatic heart disease who had undergone MVR without tricuspid valve surgery between one and 30 years (mean 11.3+/-8 years) before their last clinical examination. All patients underwent a complete color-Doppler echocardiographic examination. The predominant presurgical mitral lesion was stenosis in 44 patients and regurgitation in 21. The severity of the tricuspid valve disease was assessed echocardiographically using color-Doppler flow images and flow direction in the inferior vena cava or hepatic veins, and by clinical evaluation. RESULTS: Echocardiography revealed significant late TR in 44 patients (67%), which was moderate in 16 and severe in 28, and evident on physical examination in 24 cases (37%). Age (relative risk (RR) = 1.1; C.I. 1-1.1) and female sex (RR = 1.8; C.I. = 1.0-3.2) were identified as statistically significant predictors for late clinical TR development, but only age was found as a statistically significant predictor for echocardiographic TR development. An elevated RR for organic TR and predominant mitral regurgitation was found. In contrast, pre- and postoperative pulmonary artery pressure, predominant mitral lesion, prosthetic valve gradient and regurgitation were similar in patients with and without late TR. CONCLUSIONS: Significant TR diagnosed by echocardiography late after MVR is common, and clinically evident in more than one-third of patients. Therefore, a lower threshold for tricuspid valve repair should be considered when mitral valve surgery is carried out.

Aged↗
PubMed1996

In vitro assessment of prosthetic valve function in mitral valve replacement with chordal preservation techniques.

BACKGROUND AND AIM OF THE STUDY: The importance of chordal preservation techniques in maintaining improved left ventricular function after mitral valve replacement has been well documented clinically. Currently, the choice of prosthetic valve used in chordal preservation is dependent upon the surgeon's preference. However, the transvalvular flow characteristics of common, clinically used prosthetic valves may be influenced by the mitral subvalvular apparatus, and may result in degraded valve function. The goal of this study was to perform an in vitro evaluation of the influence of chordal preservation on the transvalvular and left ventricular flow patterns of common valve prostheses. METHODS: Tissue and mechanical valves have been evaluated under physiologic pulsatile flow with anterior and/or posterior chordal preservation. Flow patterns were assessed by 2-D planar flow visualization, pulsed wave Doppler velocity measurements, 2-D echocardiography, and selected color Doppler flow mapping. Based on changes in transvalvular and left ventricular flow patterns, favorable prosthetic valve/chordal preservation combinations were identified. Additionally, valve orientation was varied to determine optimal orientation. RESULTS: Baseline results without chordal preservation indicate that the anti-anatomic orientation is preferred for the bileaflet valve design while the tilting disc valve should be oriented with the major axis toward the posterior (free) wall of the ventricle, corroborating published conclusions by other investigators. Some form of flow restriction is observed in all test cases with chordal preservation due to the presence of the subvalvular tissue. In general, bioprostheses showed less flow restriction then the mechanical valves, particularly with lateral flow expansion. This flow restriction may influence pressure recovery downstream of the mechanical valves tested. Increased flow constriction is observed with anterior and posterior chordal preservation. CONCLUSIONS: This study favors the use of the St. Jude Medical bileaflet valve orientated in the anti-anatomic position, or the Carpentier-Edwards pericardial valve with chordal preservation.

Bioprosthesis↗
PubMed2002

Clinical evaluation of all-ceramic crowns.

STATEMENT OF PROBLEM: There are few in vivo studies on the clinical performance of all-ceramic crowns. PURPOSE: The aim of this study was to evaluate the clinical performance of IPS Empress crowns. MATERIAL AND METHODS: Thirty-seven all-ceramic IPS Empress crowns were placed in 20 patients. Twenty crowns were luted with Variolink II low-viscosity resin cement in combination with Syntac Classic dentin adhesive; the remaining 17 were luted with Variolink II in combination with Syntac Single Component. All procedural steps were performed by the same prosthodontist. Using the California Dental Association's (CDA) quality evaluation system, 2 calibrated evaluators examined the crowns for margin integrity, anatomic form, surface, and color for a period of 12 to 41 months, with a mean of 24.56 months after insertion. Kaplan-Meier statistical analysis was used to calculate the survival rate of the crowns. Values obtained for plaque and gingival conditions were compared to control teeth with use of the Wilcoxon signed ranks test (P<.05). RESULTS: Based on the CDA criteria, 94.6% of the crowns were rated satisfactory. Fracture was registered in only 1 crown. One endodontically treated tooth failed due to the dislodgement of the prefabricated dowel. No significant difference was observed in the gingival health status of crowns that had margins placed above or at the level of the gingival margin. However, in crowns that had subgingival margin finish lines, the percentage of bleeding on probing was significantly higher than that of the contralateral control teeth. CONCLUSION: In this in vivo study, IPS Empress crowns luted with both dentin bonding agents functioned satisfactorily with a relatively low fracture rate over a mean evaluation period of 24.56 months.

Adult↗
PubMed1993

Transesophageal echocardiography in the evaluation of prosthetic valves.

Biplane TEE, with its relatively low risk, has become an invaluable adjunct to comprehensive transthoracic 2-D Doppler and color flow examination. It should be undertaken in all instances in which transthoracic information is not adequate, or if there is suspicion of an abnormality not detected by TEE. One can advocate the use of TEE in the operating room in all instances wherein a patient is scheduled to undergo implantation of a prosthetic valve, because it enables baseline information to be obtained that may be valuable in the management of patients with questionable findings, permitting a comparison. The role of cardiac catheterization is limited. Hemodynamic cardiac catheterization should only be resorted to in instances in which there is discrepancy between echocardiographic findings and clinical presentation. Visualization of coronary arteries may be indicated in some situations in which a limited coronary arteriogram could be obtained. This procedure is less morbid if separated from hemodynamic catheterization of the right and left sides of the heart. Echocardiography represents the state-of-the-art in the evaluation of patients with valvular prostheses. Biplane TEE and multiplane TEE are valuable complementary technologies to TEE, when the situation dictates its use, because these modalities provide useful information that alters management of the patient.

Cardiac Catheterization↗
PubMed1979

Subclavian steal syndrome. Part 1: Proximal vertebral to common carotid artery transposition in three patients, and historical review.

Three patients with central nervous system symptoms due to subclavian steal syndrome were treated with proximal vertebral to common carotid artery transposition. Neurological symptoms were relieved or improved in all three, with no decrease in blood pressure or pulse in the ipsilateral upper extremity. The colorful history of this syndrome is reviewed, and the various surgical approaches to its treatment are discussed. Although the literature suggests that the commonly used carotid to subclavian artery bypass graft and other similar extrathoracic procedures are generally safe and effective for relief of symptoms of the steal, there is also evidence that these bypasses may fail to restore antegrade flow in the vertebral artery, and, in fact, may steal from the carotid artery. Thus, the blood flow provided to the brain by these procedure may be hardly more than that provided by vertebral artery ligation, whereas the principal effect is to restore blood flow into the upper extremity. Vertebral artery ligation alone has been used in 20 patients, with neurological improvement in all cases and production of persistent intermittent brachial claudication in only one. These considerations and our patient experience suggest that a relatively simple operation, proximal vertebral to common carotid artery transposition, which emphasizes restoration of flow to the brain rather than to the upper extremity, may be preferable for most patients with neurological symptoms of subclavian steal syndrome.

Adult↗
PubMed1994

Turbulent stresses downstream of three mechanical aortic valve prostheses in human beings.

High levels of turbulent stresses resulting from disturbed blood flow may cause damage to red blood cells and platelets. The purpose of this study was to evaluate the spatial distribution and temporal development of turbulent stresses downstream of three mechanical aortic valve prostheses in human subjects: the St. Jude Medical, the CarboMedics, and the Starr-Edwards silicone rubber ball. Blood velocity measurements were taken at 17 measuring points in the cross-sectional area of the ascending aorta 5 to 6 cm downstream of the aortic anulus with the use of a perivascular pulsed Doppler ultrasound system. Turbulence analysis was done for each of the 17 measuring points by calculating the radial Reynolds normal stresses within 50 msec overlapping time windows during systole. By coordinating the calculated Reynolds normal stress values for each time window and for all measuring points, computerized two-dimensional color-coded mapping of the turbulent stress distribution during systole was done. For the St. Jude Medical valves the highest Reynolds normal stress (27 to 63 N/m2) were found along the central slit near the vessel walls. The temporal development and spatial distribution of Reynolds normal stresses for the CarboMedics valves were quite similar to those of the St. Jude Medical valves with maximum Reynolds normal stress values ranging from 19 to 72 N/m2. The typical Reynolds normal stress distribution for the Starr-Edwards silicone rubber ball valves was asymmetric, revealing the highest Reynolds normal stresses (11 to 56 N/m2) at various locations in the annular region between the ball and the vessel wall. The spatial distribution and temporal development of turbulent stresses downstream of the three investigated mechanical aortic valve prostheses correlated well with the superstructure of the valves. The maximum Reynolds normal stresses for the three valve types were in the same order of magnitude with exposure times sufficient to cause sublethal damage to red blood cells and platelets.

Adult↗