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At least 775 records · Page 43Linked to original sources
PubMed2000

Intra-aortic balloon pump associated with dynamic left ventricular outflow tract obstruction after valve replacement for aortic stenosis.

An unstable patient with critical aortic stenosis had an intra-aortic balloon pump placed preoperatively for hemodynamic support and alleviation of symptoms. After separation from cardiopulmonary bypass following aortic valve replacement, the patient was hypotensive with increased pulmonary artery pressures. Transesophageal echocardiography revealed left ventricular outflow tract obstruction associated with systolic anterior motion of the mitral valve and severe mitral regurgitation. This pathophysiology was present when ventricular systole was preceded by balloon counterpulsation, but was absent during unassisted systole. This case report demonstrates a potentially significant untoward effect of intra-aortic balloon pump augmentation after aortic valve replacement for aortic stenosis. The timely diagnosis of this iatrogenic condition in the operating room permitted the prompt implementation of appropriate management strategies and avoided unnecessary surgical intervention.

Aged↗
PubMed2002

The repeatability of an intraoral dental colorimeter.

STATEMENT OF PROBLEM: Characterizing and reproducing color remain one of the most challenging aspects of dentistry. A relatively new intraoral colorimeter measures the color of natural teeth and metal-ceramic restorations and prints out a color recipe for the Vintage Halo Porcelain System. The reliability of the colorimeter is unknown. PURPOSE: The purpose of this study was to evaluate the reliability of a contact dental colorimeter and to correlate the shade registered by the colorimeter with the shade selected by experienced clinicians. MATERIALS AND METHODS: In part I of the study, 2 examiners (A and B) took 2 colorimeter measurements from the maxillary right central incisors of 11 subjects. The examiners were blinded to their own data and those of other investigators. The readings were repeated 3 weeks later with the same protocol. The Cronbach alpha reliability coefficient was used to analyze the collected data. In part II of the study, 2 experienced clinicians (examiners D and E) selected a shade from the classic Vita Lumin Vacuum shade guide for the maxillary right central incisors of the same 11 subjects. The clinicians were blinded to each other's selections and the colorimeter readings. It should be noted that the manufacturer of the colorimeter uses the terms shade, value, and hue to represent chroma, value, and hue, respectively, as defined in the Glossary of Prosthodontic Terms (J Prosthet Dent 1999;81:39-110). RESULTS: The reliability analysis results for each of the combined trials for shade, value, and hue were all >.94. The interexaminer reliability alpha values were >.9 for shade and value and.64 to.74 for hue. The interexaminer alpha represented the value range of each of 4 measurements. The intraexaminer reliability alpha values for shade, value, and hue were.99,.95, and.96 for examiner A and.99,.93, and.97 for examiner B, respectively. In part II of the study, the colorimeter agreed with itself 82% of the time, whereas clinicians agreed with each other on the selected shade 73% of the time. Selections made by the colorimeter and the clinicians matched 55% to 64% of the time. CONCLUSIONS: Within the limitations of this study, the colorimeter reliably measured the color of natural teeth.

Ceramics↗
PubMed2002

The results of total arch graft implantation with open stent-graft placement for type A aortic dissection.

BACKGROUND: One problem that conventional ascending treatment for type A aortic dissection has not satisfactorily resolved is chronic enlargement of residual dissection in the aortic arch and descending aorta. To address this problem, we have developed a new method for type A aortic dissection: total arch graft implantation with open-style stent-graft placement. METHODS: From October 1994 through October 1999, 19 patients with type A aortic dissection (13 acute and 6 chronic dissections) underwent total arch graft implantation with open-style stent-graft placement. After achievement of general anesthesia and hypothermic extracorporeal circulation, we replaced the dissected ascending aorta and neck vessels with a 4-branched graft and repaired the descending aorta with a stent graft to close the entry site completely and to obtain better peripheral perfusion. We then examined the acute-phase and chronic-phase results and the outcomes of the false lumen and dissected aorta. RESULTS: There were 1 (5.3%) hospital death and 2 late deaths. The survivals at 1 and 3 years were 89.5% and 82.6%, respectively. The following complications occurred in the perioperative period: 1 stroke, 2 cases of temporary paraparesis, 2 cases of temporary hemodialysis, and 3 cases of mediastinitis. No pulmonary complications were observed. Six months postoperatively, the targeted entry sites were completely closed in all cases, 80% (8/10) of preoperatively patent false lumina were clotted at the level of the end of the stent graft, and 60% (9/15) of the false lumina and 40% (6/15) of the dissected aorta had shrunk significantly. Two (13.3%) of 15 cases of postoperative dilatation in the dissected aorta were observed, and reoperation related to residual dissected aorta was performed in only 1 (1/17 [5.9%]) patient during the mean follow-up period of 2.4 +/- 1.6 years. CONCLUSION: Our preliminary review of the total arch graft implantation with a stent graft suggests that this new procedure for type A aortic dissection might provide better results in both the acute and the chronic phase, especially with regard to the outcome for the false lumen and dissected aorta.

Adult↗
PubMed1994

Assessment of chronic tricuspid regurgitation by colour Doppler echocardiography: a comparison with angiography in the catheterization room.

Colour Doppler echocardiographic (CDE) assessment of tricuspid regurgitation (TR) has been limited by the lack of an accepted model against which it can be compared. Angiography is said to be inadequate because catheter placement across the tricuspid valve could induce artifactual TR. Thirty-five consecutive patients with left-sided valvulopathy and recent heart failure were studied. Angiography was validated by CDE, which demonstrated that catheter placement across the tricuspid valve did not increase the size of the regurgitant jet in the first 30 cases. All the patients were studied with CDE immediately before performing the angiography in order to compare the findings of both techniques. From all the CDE parameters measured among the angiographic groups, the jet area overlapped the least (P = 0.024). The diameters of the right cardiac chambers were larger in angiographically severe cases (P = < 0.003 to 0.041), and a scale of severity that combined jet area and right atrium area showed an excellent correlation with angiography (r = 0.924; P < 0.001). Furthermore, maximal instant systolic gradients between the right cavities, estimated by catheterization, were lower in severe cases (P = 0.038). Assessment of these gradients by continuous Doppler can enhance recognition of severe TR. The analysis of jet area, right atrium area and regurgitant gradient by CDE can provide excellent assessment of TR.

Adult↗
PubMed1995

Multiplane transoesophageal echocardiography and morphology of regurgitant mitral valves in surgical repair.

BACKGROUND: An essential step in the surgical management of patients with mitral regurgitation, is a thorough understanding of the pathophysiological mechanism. This information can be obtained by multiplane transoesophageal echocardiography which displays all the components of the incompetent valve. METHODS AND RESULTS: Forty-nine patients were scanned intra-operatively by multiplane transoesophageal echocardiography, and findings compared with those at visual inspection during surgery. The pre-operative diagnosis was prolapse of the anterior mitral leaflet in nine patients (sensitivity 100%, specificity 95%), prolapse of the posterior leaflet in 17 patients (sensitivity 100%, specificity 94%) and prolapse of both leaflets in eight patients (sensitivity 87%, specificity 100%). In 11 patients annular dilatation with no abnormalities in mitral leaflet closure or motion was diagnosed (sensitivity 73%, specificity 100%). Two patients had a false-positive diagnosis of prolapse of the anterior leaflet, two others on the posterior leaflet. A prolapse of both leaflets was overlooked in one patient. Multiplane transoesophageal echocardiography scanned the mitral valve, disclosing the extent of pathology along the closure line of leaflets in 88% of patients with mitral valve prolapse. The antero-posterior diameter of the mitral annulus was measured: a diameter over 35 mm indicated annular dilatation. Using this criterion, sensitivity was 89% and specificity 100%. CONCLUSIONS: Multiplane transoesophageal echocardiography enabled components of the mitral valve to be examined systematically, and provided important information on the pathophysiological mechanism of mitral regurgitation before surgical repair. The method also allowed the surgical outcome to be assessed, offering the possibility of optimal repair.

Adult↗
PubMed2005

Increasing cardiac output by fluid loading: effects on indocyanine green plasma disappearance rate and splanchnic microcirculation.

BACKGROUND: Sufficient cardiac pre-load for maintaining adequate cardiac output is a major goal in the treatment of critically ill patients. We studied the effects of increasing cardiac output by fluid loading on the indocyanine green plasma disappearance rate (ICG-PDR) and gastric mucosal regional CO2 tension (PRco2) as an indicator of splanchnic microcirculation. METHODS: With approval by our ethics committee and written consent, we studied post-operatively 12 patients (1 female, 11 males; 66 +/- 13 years) with elective coronary artery bypass grafting (n = 10) or aortic valve replacement (n = 2). All patients had received pulmonary artery and left atrial catheterization previously for clinical indications. Cardiac output and filling pressures were measured immediately after intensive care unit (ICU) admission and 1 h after the beginning of fluid loading. RESULTS: Overall, 630 +/- 130 ml of 6% hydroxyethylstarch (130 kDa) was infused with the splanchnic perfusion pressure remaining constant. Norepinephrine and epinephrine dosages were unchanged. The cardiac index increased significantly from 2.8 +/- 0.7 to 3.5 +/- 0.6 l/min/m2 and the stroke volume index from 30 +/- 7 to 38 +/- 8 ml/m2. ICG-PDR showed no significant change, i.e. from 21.2 +/- 6.5 to 21.6 +/- 6.5%/min. Gastric mucosal PRco2 and the Pco2 gap (difference between regional and end-tidal CO2 tension) were constant, i.e. changed from 5.1 +/- 0.8 to 5.5 +/- 1.1 kPa and from 0.9 +/- 0.5 to 1.0 +/- 0.7 kPa, respectively. CONCLUSION: Increasing cardiac output to supranormal values by fluid loading is not associated with a significant change in ICG-PDR or gastric mucosal PRco2.

APACHE↗
PubMed2000

Stanford type A aortic dissection in a hypertensive patient with atherosclerosis of aorta and aortitis.

Dissection of aorta is a serious condition; the main factors are hypertension and diseases of the connective tissue or of collagen. Aortitis syndrome in combination with hypertension and atherosclerosis in association with ascending aortic dissection is rarely seen. We present the case of a 53-year-old hypertensive patient whose ascending aortic dissection was associated with pericardial effusion without rupture of the aorta and with pleural effusion. Several unusual aspects of transesophageal echocardiography are described. The intraoperative biopsy revealed inflammatory aortitis with mural hematoma, without giant cells. The literature concerning aortic dissection and aortitis is reviewed.

Aortic Dissection↗
PubMed2000

Transvenous pacemaker leads do not worsen tricuspid regurgitation: a prospective echocardiographic study.

Limited prospective data are available regarding the influence of pacemaker leads on tricuspid valve function. To examine the true incidence of these complications, 35 patients were prospectively examined by two-dimensional and Doppler echocardiography before and after implantation of either a permanent pacemaker or an automatic implantable cardioverter-defibrillator. Of the 35 patients imaged preoperatively, the amount of tricuspid regurgitation (TR) was judged as normal or trivial in 15 (43%), mild in 10 (29%), moderate in 8 (23%), and severe in 2 (6%). Following electrode implantation, TR was noted to be normal or trivial in 13 (38%), mild in 15 (48%), moderate in 6 (17%) and severe in 1 (3%). We conclude that implantation of permanent right ventricular electrodes is not usually associated with an acute worsening of tricuspid regurgitation in most patients.

Aged↗
PubMed2004

Acute improvement in global and regional left ventricular systolic function after percutaneous heart valve implantation in patients with symptomatic aortic stenosis.

BACKGROUND: The newly developed percutaneous heart valve (PHV) implantation technique decreases transaortic pressure gradient in patients with aortic stenosis. PHV replacement effects on left ventricular (LV) global and regional systolic function are currently unknown. METHODS AND RESULTS: Eight patients with severe aortic stenosis had 2D echocardiography at baseline and 24 hours after PHV implantation to evaluate changes in LV volume and LV ejection fraction. Regional function, ie, both peak systolic anterior and posterior wall tissue velocity, as well as strain and strain rate imaging, were measured by tissue Doppler imaging from a short-axis view. At 24 hours, a significant reduction in transaortic mean pressure gradient (from 46+/-15 to 8+/-3 mm Hg; P<0.0001) was accompanied by an increase in aortic valve area (from 0.59+/-0.11 to 1.69+/-0.11 cm2; P<0.0001). LV end-diastolic volume remained unchanged (102+/-36 to 101+/-12 mL; P=NS), whereas LV ejection fraction increased (48+/-18% to 57+/-12%; P<0.01). Improvement in posterior wall displacement (posterior wall tissue velocity increased from 2.2+/-0.5 to 4.4+/-1.0 cm/s(-1); P=0.0003) and deformation (strain rate imaging increased from 1.0+/-0.3 to 1.9+/-0.7 s(-1), P=0.009, and strain increased from 11+/-5% to 17+/-9%; P=0.02) were observed. CONCLUSIONS: Immediately after PHV replacement, improvement of LV global and regional systolic function was evidenced by tissue Doppler imaging.

Aged↗
PubMed1988

Detection, localization, and quantitation of bioprosthetic mitral valve regurgitation. An in vitro two-dimensional color-Doppler flow-mapping study.

The usefulness of two-dimensional color-Doppler flow-imaging (2D Doppler) in the detection, localization, and quantitation of bioprosthetic mitral valve regurgitation is uncertain. Mitral bioprostheses, before and after the creation of transvalvular (n = 33), paravalvular (n = 17), or combined (n = 23) defects, were mounted in a pulsed duplication system (flow rates, 2.5-6.5 l/min; pulse rate, 70 beats/min). An Aloka 880 2D Doppler system (Japan) was used to image the regurgitant jets in the simulated left atrial chamber, analogous to images obtained with transesophageal echocardiography. Jet area was corrected to an estimate of stroke volume: 2D Doppler measurements were divided by [(valve effective orifice area) X (continuous-wave Doppler-determined mean diastolic filling velocity)]/pulse rate. Regurgitant fraction and regurgitant volume were measured by an electromagnetic flow probe. 2D Doppler correctly identified the presence and location of paravalvular regurgitation. In transvalvular and combined transvalvular-paravalvular defects, there were six incorrect interpretations, all having transvalvular regurgitant volumes less than 4 ml/beat. In the presence of transvalvular regurgitation, jet area, length, and width correlated linearly with regurgitant volume (r = 0.82, 0.80, and 0.68, respectively; p less than 0.0001) and regurgitant fraction (r = 0.62, 0.61, and 0.45, respectively; p less than 0.001). Correlations with regurgitant fraction were improved when 2D Doppler measurements were corrected for stroke volume (r = 0.78, 0.79, and 0.67, respectively; p less than 0.0001). Mitral bioprostheses with transvalvular defects were also studied at varying flow rates (3.2-7.5 l/min) and pulse rates (70, 90, and 110 beats/min). The correlation between jet area and regurgitant volume was improved with a second-order polynomial regression (r = 0.93, p less than 0.0001). Our conclusions are that 1) in this in vitro model analogous to transesophageal imaging, 2D Doppler accurately detects and localizes bioprosthetic mitral valve regurgitation; 2) in transvalvular bioprosthetic mitral valve regurgitation, 2D Doppler measurement of jet area has a curvilinear relation with regurgitant volume, and correlation with regurgitant fraction is improved with correction for stroke volume; and 3) in paravalvular bioprosthetic mitral valve regurgitation, correlations between 2D Doppler measurements and regurgitant volumes are weaker, possibly because of jet eccentricity.

Animals↗
PubMed1992

Color Doppler regurgitant characteristics of normal mechanical mitral valve prostheses in vitro.

BACKGROUND: To evaluate normal regurgitant characteristics of St. Jude (SJ) and Medtronic-Hall (MH) mitral valves, four sizes (25-31 mm) of each were studied in a pulsatile flow model. METHODS AND RESULTS: Regurgitant flow was measured by flowmeter at left ventricular pressures of 80, 130, and 180 mm Hg. Peak regurgitant flow rates ranged from 6.2 to 12.7 cm3/sec in SJ valves and from 7.9 to 17.5 cm3/sec in MH valves. Regurgitant orifice areas calculated from the Doppler continuity equation ranged from 1.6 to 2.0 mm2 in SJ valves and from 2.2 to 2.9 mm2 in MH valves. Regurgitant volumes across the closed valve at a left ventricular pressure of 130 mm Hg were normalized to an ejection time of 280 msec and ranged from 1.5 to 1.9 cm3 in SJ valves and from 2.1 to 2.8 cm3 in MH valves. Jets were imaged by color Doppler in six rotational planes, and jet size and morphology were compared with those of regurgitant jets from circular orifices with sizes comparable to the calculated prosthetic valve regurgitant orifices (1.1-3.1 mm2). SJ valves showed two converging jets from the pivot points, one central jet, and a variable number of peripheral jets. The mean color jet area derived from the six image planes ranged from 1.6 to 5.3 cm2. Aliasing occurred only close to the valve (maximal distance 0.5-2.0 cm). MH valves showed a large central jet with a maximal length of aliased flow between 2.0 and 5.5 cm. Depending on valve size, driving pressure, and image plane, one or two small peripheral jets were found. These jets did not show aliasing in any case. The mean color jet area ranged from 5.1 to 11.0 cm2. Jets originating from circular orifices of comparable size showed jet areas from 5.5 to 13.9 cm2 and aliasing distances from 3.3 to 7.3 cm. At similar regurgitant orifice areas, driving pressures, and regurgitant flows, the measured color areas and aliasing distances were smallest in SJ valves, larger in MH valves, and largest in simple circular orifices. CONCLUSIONS: Large, complex regurgitant jets can be found in normal closed SJ and MH valves by color Doppler, although regurgitant flow volume is minimal. Jet size and velocity distribution differs markedly between SJ valves, MH valves, and circular orifices, even with comparable driving pressure, regurgitant orifice area, and regurgitant volume. The characteristic patterns of normal regurgitation must be recognized to avoid incorrect diagnoses of pathological regurgitation in SJ and MH prosthetic valves. MH valves should not be removed solely on the basis of a central regurgitant jet with a long aliasing distance. Peripheral jets in MH valves and all jets in SJ valves should be considered normal as long as no or only minimal aliasing is present. In contrast, peripheral jets with significant aliasing may represent strong evidence of pathological regurgitation.

Blood Flow Velocity↗
PubMed2006

Facing the challenges of ceramic veneers.

Ceramic veneers are extremely popular and have been used for many years. In spite of their phenomenal success, they offer numerous challenges during service. In this column, I have identified and discussed several degenerative situations commonly observed, and I have described methods of preventing or reducing the problems. When properly placed, ceramic veneers are among the most beautiful and long-lasting of all dental restorations.

Ceramics↗
PubMed2003

Malachite green and phthalocyanine-silver reactions reveal acidic phospholipid involvement in calcification of porcine aortic valves in rat subdermal model.

Subdermal implant models are helpful in the study of calcification "in vivo" and for testing anticalcific treatments. After implantation of porcine aortic valve leaflets in rat subcutis, we previously found that glutaraldehyde-Cuprolinic blue reactions (GA-CB) at low pH induce favourable tissue unmasking from mineral deposits, and visualize peculiar, electrondense layers that outline the calcifying cells and matrix vesicle-like structures. The layer-forming material seemed to consist of acidic phospholipids because of its anionic nature and differential susceptibility to chemical/enzymatic extractivity. In the present investigation, pre-embedding glutaraldehyde-Malachite green (GA-MG) reactions and subsequent osmium post-fixation were compared with pre-embedding GA-CB reactions, combined with post-embedding von Kossa silver staining (GA-CB-S), to assess whether the layer-forming material is actually composed of acidic phospholipids and exhibits calcium-binding properties. After lowering standard pH, GA-MG reactions also caused sample demineralization and the appearance of pericellular osmium-MG-reactive layers comparable to CB-reactive ones. Moreover, GA-CB-S reactions showed that major silver precipitation was superimposed to the CB-reactive layers, whereas minor metal extra-precipitation occurred at three distinct, additional sites. These results demonstrate that a unique process of cell degeneration occurs in this calcification model, in which acidic phospholipids accumulate at cell surface, replacing cell membrane and acting as major apatite nucleator. However, the overall observations are consistent with the hypothesis that certain phases are common to the various types of normal and/or abnormal calcification.

Animals↗
PubMed1997

Concealed left ventricular hypertrophy and diastolic dysfunction in hypertrophic cardiomyopathy in the presence of acute left ventricular volume overload. A case report.

We report a patient in whom hypertrophic cardiomyopathy, with both left ventricular hypertrophy and diastolic dysfunction, was masked by acute severe aortic regurgitation and marked left ventricular dilation. Upon admission, 1) two-dimensional echocardiogram of the left ventricle revealed a dynamic and flail vegetation on the aortic right coronary cusp and marked left ventricular dilation, 2) a massive aortic regurgitant signal was recorded by color Doppler flow imaging, and 3) transmitral flow velocity by pulsed Doppler echocardiogram revealed a pseudonormalization. However, symmetric hypertrophy of the left ventricular wall, a decrease in early diastolic wave and a compensatory increase in atrial systolic wave of the transmitral flow velocity appeared after successful aortic valve replacement.

Aortic Valve↗
PubMed2001

The effect of an immunosuppressive therapy and its withdrawal on bone healing around titanium implants. A histometric study in rabbits.

BACKGROUND: Immunosuppressive agents have been recognized as a factor affecting bone metabolism. We investigated the consequences of the administration and withdrawal of cyclosporin A/nifedipine on bone around titanium implants to observe whether these changes occur and if they are reversible. METHODS: Twenty-eight New Zealand rabbits were included in the study. Following anesthesia, the tibiae surface was exposed, and 2 screw-shaped implants 7.0 mm in length and 3.75 mm in diameter were placed bilaterally. The animals were randomly assigned to 1 of 4 experimental groups and received daily subcutaneous injections for 14 days: groups A and C were injected with vehicle while groups B and D received cyclosporin A (10 mg/kg) plus nifedipine (0.5 mg/kg). Groups A and B were sacrificed 14 days and groups C and D 42 days postoperatively. The degree of bone contact with the implant surface and the bone area within the limits of the threads of the implant were measured. RESULTS: Intergroup analysis revealed no significant difference (P > 0.05) in the degree of bone contact with the implant surface between the control and test groups on days 14 and 42. In contrast, the treated animals demonstrated a significant (P < 0.05) decrease in the bone area within the limits of the threads of the implant in both periods. CONCLUSIONS: The data of the present study suggest that the use of cyclosporin A/nifedipine may influence bone healing around titanium implants. This observation may have important clinical implications.

Animals↗
PubMed2000

Color flow signal in the left atrium as a mirror image artifact suggesting one leaflet constriction of the St. Jude Medical valve: a case report.

Color Doppler echocardiography detected an abnormal color flow signal originating from the prosthetic mitral valve and extending to the left atrium during diastole in an 84-year-old woman with St. Jude Medical valve replacement. The flow was away from the transducer and almost identical to the left ventricular inflow signal except for the direction. Cinefluoroscopy showed one of the leaflets fixed at systole whereas the other leaflet was mobile. After reinforcement of anticoagulant therapy, this abnormal color flow signal disappeared and motion of both leaflets normalized. This color flow signal, presumably a mirror image artifact of the left ventricular inflow caused by the immobilized leaflet, could be a sign of one leaflet constriction in patients with St. Jude Medical valve replacement.

Aged↗