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PubMed1991

Diagnostic value of transesophageal echocardiography in cardiac surgery.

The aim of this study was to assess the diagnostic value of intraoperative 2-D color Doppler transesophageal echocardiography (ITEE) for the surgeon and anesthesiologist in patients undergoing coronary bypass surgery or heart valve replacement. Information given by ITEE in 100 cardiac operations was documented. We judged the ITEE information, considering to what extent it was not to be obtained by other methods and to what extent it influenced the operation itself. The value was classified as dispensable (0), informative (1), valuable (2), or essential (3). In 50 consecutive patients with heart-valve replacement (25 aortic valve prostheses, 25 mitral valve prostheses) ITEE was 38 x (0), 8 x (1), 4 x (2). In 50 consecutive patients undergoing coronary artery bypass graft surgery it was 33 x (0), 11 x (1), 4 x (2), 2 x (3). The two essential diagnoses referred to undetected vein graft occlusions. Information classified as valuable mainly referred to left and right ventricular function or valvular and prosthetic valve function when difficulties occurred during and after extracorporeal circulation. In conclusion, information given by ITEE, although generally regarded as dispensable in the procedures considered, was valuable in 10% of cases and in 2% even essential.

Cardiac Surgical Procedures↗
PubMed1996

Effects of Ca and H2O2 added to RPMI on the fretting corrosion of Ti6Al4V.

Titanium and its alloys have demonstrated considerable success in various surgical procedures including orthopedic, dental, and cardiovascular surgery. However, particulate debris from corrosion and wear is present in a considerable quantity in tissue local to the implant. This study evaluated the effect of Ca, since it is present in both serum and bone, and H2O2, since it is produced through local inflammation, on the amount of titanium release. Four sets of Ti6Al4V plates and Ti6Al4V screws were used. Each set was designated to one of four solutions: RPMI (cell culture growth media), RPMI with CaCl2, RPMI with CaCO3, and RPMI with H2O2. A fretter was used to cause corrosion by creating micromotion between two screws and a two-hole plate of Ti6Al4V. After fretting for 72 h, weight loss of the plate and screws and the amount of Ti and vanadium (V) in solution was used to assess the amount of fretting corrosion which had occurred. Results of weight loss and Ti in solution indicated that the presence of H2O2 increased the amount of particulate debris produced in RPMI as compared with RPMI alone. The addition of CaCl2 to RPMI also increased both weight loss and Ti in solution compared with RPMI alone. The addition of CaCO2, however, did not give values significantly different from RPMI alone. Comparison of weight loss and Ti in solution indicated that the increase in fretting corrosion was not different between RPMI with CaCl2 and RPMI with H2O2. The particulate wear debris from the four solutions was black in color and the size of the particulate produced was compared using a Coulter Multisizer. The results indicated that particles produced in the four solutions were not different, with mean values between 1.324 and 1.100 microns, and they were similar in size to the particulate found in tissues surrounding failed total hip replacements. In order to better understand the role of Ca in the fretting corrosion of Ti6Al4V, energy dispersive x-ray analysis (EDXA) using SEM was used to determine elemental composition of one countersink surface of a plate which had been run four times in RPMI with CaCl2. The presence of Ca in the bulk was not significant (% composition < 0.5%). However, Ca was present in two surface particles which were examined at a magnification of 55,000, with a Ca% composition of 63.2% and 19.2%. While results from this study indicate that both soluble Ca(CaCl2) and H2O2 increase the fretting corrosion of Ti6Al4V, the insoluble form of Ca, which would be found in bone and hydroxyapatite, has no effect. These data indicate that it is important to specify the media used in corrosion, dissolution, and elution experiments.

Alloys↗
PubMedDate not supplied

Quantitative reduction of methyl tetrazolium by fresh vein homograft biopsies in vitro is an index of viability.

OBJECTIVE: The color density of the methyl tetrazolium (MTT) test is proportional to mitochondrial enzyme activity thus reflecting cellular viability. The aim was to evaluate the MTT test as a viability assay for vein homograft studies. MATERIALS AND METHODS: Fresh intact vein samples were harvested during multi-organ procurement. The reliability of the MTT assay was tested by a fluorescent dye combination (1 microg/ml propidium iodide PI and 4 microM/ml SYTO-16 stains). The enzyme kinetics of the reaction was also investigated. The optimal reagent concentration, biopsy size and incubation period were established. RESULTS: There was a linear relationship between the vein homograft's weight and the pigment production activity. A nonspecific reaction (8.6%) was observed in negative controls. The MTT cleavage up to 0.1% (w/v) follows the Michaelis kinetics. The Michaelis constant (2,805 +/- 130 microM), the maximal velocity (196 +/- 2.2 x 10(-5 )microM s(-1)) and the velocity constant (6.98 +/- 0.2 x 10(-7) s(-1)) was calculated. The viability assessed by fluorescent dyes simultaneously visualized the live/dead cell ratio, which can be calculated by image analysis software. CONCLUSION: The use of MTT in colorimetric assays offers high sensitivity. The assay is simple, inexpensive, and reproducible in vein homograft studies.

Adult↗
PubMed1997

Organ perfusion with Hemopump device assistance with and without intraaortic balloon pumping.

OBJECTIVE: Our objective was to analyze the potential advantage of combining an intraaortic balloon pump with a transthoracic Hemopump device (Medtronic, Inc., Minneapolis, Minn.) (Nimbus Medical, Inc., Rancho Cordova, Calif.). METHODS: Twelve sheep underwent implantation of a transthoracic Hemopump device and an intraaortic balloon pump. In the first series (n = 6), we analyzed the influence of the counterpulsation on the performance of the Hemopump device. In the second group (n = 6), hemodynamic changes, myocardial wall thickening, organ perfusion, and myocardial perfusion (determined with colored microspheres) were analyzed under the following conditions: (1) control situation, (2) during application of coronary stenosis, (3) during support with the Hemopump device, and (4) during support with the Hemopump device combined with intraaortic balloon pump support. RESULTS: In the first series, we found that addition of counterpulsation reduced output with the Hemopump device by 11.1% +/- 6%. In the second series, it was shown that coronary stenosis significantly reduced contractility (rate of pressure change and wall thickening) but did not cause hemodynamic collapse. Myocardial blood flow was significantly reduced in the poststenotic subendocardial regions (mean subendocardial blood flow dropped from 78 +/- 33 to 24 +/- 17 ml/min/100 gm; p = 0.0486). Support with the Hemopump device alone improved the ratio of subendocardial to subepicardial blood flow, but endocardial underperfusion remained (analysis of variance, p < 0.001). The Hemopump device with an intraaortic balloon pump completely restored perfusion in poststenotic regions. Peripheral organ perfusion did not change during ischemia or mechanical support. CONCLUSIONS: The association of balloon counterpulsation with the Hemopump device reduces the Hemopump output by 11% and increases myocardial blood flow to ischemic regions. Perfusion to peripheral organs remains unaltered. The transthoracic Hemopump device combined with an intraaortic balloon pump is an ideal support system for the ischemic, failing heart.

Analysis of Variance↗
PubMed1996

Transcranial high-intensity Doppler signals in patients with mechanical heart valve prostheses: their relationship with abnormal intracavitary echoes.

BACKGROUND AND AIMS OF THE STUDY: In preceding studies, we reported that abnormal Doppler signals of high intensity (HITS) were frequently found in the cerebral arteries of patients with prosthetic mechanical heart valves. These signals should be attributed either to air microbubbles, possibly due to cavitations or to solid emboli elements. On the other hand, the presence of abnormal intracardiac echoes has been reported in patients with mechanical valves. These echoes should be also attributed to air microbubbles or to formed elements. Although in vitro experiments are in favor of the first explanation, the discussion of their origin remains open. METHODS: Among patients subjected to a transesophageal echocardiography (TEE), we selected subjects with mechanical prosthetic heart valves, according to the following criteria: (i) normally functioning valves; (ii) bright echoes suggesting microbubbles, inside the prosthetic valve and/or upstream from it (left ventricular outflow tract or left atrium); (iii) no morphological lesions that could generate solid microemboli at the prosthetic level; (iv) normal carotid arteries, as investigated by color echo-Doppler. RESULTS: Twenty patients were selected: 11 men and nine women of age range 40-64 years. They were implanted with mechanical heart valves (24 Saint-Jude Medical, three Björk-Shiley and one CarboMedics) in the mitral position (10), aortic position (two), or mitral and aortic position (eight) for periods ranging from 10 days to 17 years. There was no major left ventricular dysfunction (mean end-diastolic diameter 51.8 mm; mean ejection fraction 59%). The mean diameter of the left atrium was 46.1 mm. All but three patients were in sinus rhythm; seven had presented with a transient ischemic attack or amaurosis within the six months preceding the investigation. Immediately after TEE, Doppler signals were recorded on the middle cerebral arteries (MCA) during 10 minutes on each side, and the abnormal Doppler signals were counted. Seventeen subjects (85%) exhibited HITS repetition rate from 0.2 to 5.5 per min. CONCLUSION: The percentage of patients with HITS in a non-selected group with mechanical heart valves was about 50%, as observed in previous studies. It appears that in a selected group of patients the percentage with HITS is consistently higher. Therefore, HITS and abnormal intracardiac echoes could have a common origin.

Adult↗
PubMed1999

Aortic root geometry and stentless porcine valve competence.

The goal of this study was to characterize medium-term changes in aortic root geometry after stentless aortic valve replacement, the relationship between aortic sinotubular junction and the competence of stentless valves. A total of 205 consecutive patients (mean age 73+/-6 years; 120 men, 85 women) received a Freestyle stentless porcine aortic valve and were studied prospectively by echocardiography from 1 week to 5 years. Internal diameters of outflow tract, annulus, sinus, sinotubular junction, and ascending aortic root were measured at early ejection and indexed to stentless valve size. The degree of stentless valve regurgitation was semiquantified by color Doppler echocardiography. A total of 701 echocardiographic studies were obtained and analyzed; 73% showed a fully competent stentless valve (nAR) and 13% and 14%, respectively, showed a trivial (tAR) or mild (mAR) regurgitation. Sinotubular junction of tAR or mAR was significantly greater than that of nAR (111+/-1.9, 117+/-2.2 vs. 104+/-1.0, percentage of valve size, P<.001). A preoperative diagnosis of aortic regurgitation (110+/-2.6 vs. 104+/-1.0, percentage of valve size, P<.001) and 4 to 5-year follow-up time (116+/-2.2 vs. 107+/-2.9, percentage of valve size, P = .023) were associated with a greater sinotubular junction, although the incidence and mean grade of stentless valve regurgitation did not change significantly during the follow-up period. Up to medium-term follow-up evaluation, the incidence of moderate stentless aortic regurgitation is less than 5%. The nature of valve disease and age-related increase in sinotubular junction may have reduced the cusp coaptation area of the stentless valve and may predict the presence of a trivial or mild regurgitation. Understanding the interrelations between the stentless valve and remodeling of the aging aorta has important implications for both surgical technique and long-term follow-up outcome.

Aged↗
PubMed1999

Transcatheter closure of secundum atrial septal defects with the new self-centering Amplatzer Septal Occluder.

AIMS: The study was set up to find out whether a new self-centering prosthesis for transcatheter closure of secundum atrial septal defects could overcome the disadvantages of previously described devices. METHODS AND RESULTS: Fifty-two consecutive patients with a significant atrial septal defect were considered for transcatheter closure with the Amplatzer Septal Occluder. The device, made of a Nitinol and polyester fabric mesh, provides a different approach to defect occlusion by stenting the atrial septal defect up to a stretched diameter of 26 mm. Three infants whose large defects were demonstrated on a transthoracic echocardiogram were excluded from transcatheter treatment. On transoesophageal echocardiography, 49 defects ranged from 6-26 mm, in one adult the defect measured 28 mm and this patient was excluded from attempted transcatheter closure. At cardiac catheterization in five further patients, devices were not implanted, in two because the stretched diameter exceeded 26 mm and in three the device was withdrawn because it was unstable or compromised the mitral valve. Thus, device closure was performed in 43 patients. At follow-up after 3 months the complete closure rate was 97%. CONCLUSION: The self-centering Amplatzer Septal Occluder is very efficient and user-friendly and offers interventional closure in 83% of an unselected group of patients presented with an atrial septal defect.

Adolescent↗
PubMed1991

Freehand allograft aortic valve replacement and aortic root replacement. Utility of intraoperative echocardiography and Doppler color flow mapping.

UNLABELLED: Seventeen consecutive patients undergoing 20 planned aortic valve replacements with allograft valves at Stanford University Medical Center were studied with intraoperative epicardial echocardiography and Doppler color flow mapping before and after cardiopulmonary bypass. Native aortic valves were replaced in 12 of the 20 patients, and eight patients underwent second aortic valve procedures. In 17 of 20 patients allograft selection was guided by prebypass echocardiographic estimates of annular diameter and/or length of allograft aortic root required. Other prebypass findings included unanticipated severe mitral regurgitation in one patient (which precluded allograft aortic valve replacement), left-to-right shunts in five patients, ascending aortic dissection in one, and aortic root disease necessitating coronary reimplantation or bypass in two. Postbypass echocardiography demonstrated acceptable competency of 18 of 19 allograft valves (mild or no aortic insufficiency). Postbypass echocardiography also documented successful repair of four of five shunts and mild mitral regurgitation in 15 of 19 patients (versus 11 of 19 before bypass). CONCLUSIONS: Intraoperative echocardiography-Doppler mapping is a useful adjunct for allograft aortic valve or aortic root replacement; it allows confident selection of appropriate tissue size before aortic cross clamping, which minimizes delay from allograft thawing procedures. It also provides helpful information about the extent of aortic root disease and coronary ostial anatomy before bypass, confirms allograft competency after bypass, and detects accompanying valvular and other hemodynamic lesions before and after allograft valve replacement.

Adult↗
PubMed2002

Eight-year results of aortic root replacement with the freestyle stentless porcine aortic root bioprosthesis.

BACKGROUND: Stentless porcine aortic valves offer several advantages over traditional valves. Among these are superior hemodynamics, laminar flow patterns, lack of need for anticoagulation, and perhaps improved durability. METHODS: One hundred four patients were operated on from September 17, 1992, to October 31, 1997, as part of a multicenter worldwide investigation of the Medtronic Freestyle stentless porcine bioprosthesis. All patients received a total aortic root replacement. The patients were evaluated postoperatively at discharge, at 3 to 6 months, and yearly by clinical examination and color flow Doppler echocardiography. RESULTS: Operative mortality was 3.9%. No patient experienced structural valve deterioration, nonstructural deterioration, perivalvular leak, or unacceptable hemodynamic performance. At 8 years, survival was 59.8%. Freedom from thromboembolic complications was 83.3%. Freedom from postoperative endocarditis was 96.9%. Freedom from reoperation was 100%. Mean systolic gradients did not change over the time period studied. They were 6.4 +/- 3.8 mm Hg at 1 year and 6.7 +/- 2.6 mm Hg at 8 years. Correspondingly, effective orifice area was 1.9 +/- 0.7 cm2 at 1 year and 1.8 +/- 0.8 cm2 at 8 years. The incidence of any aortic insufficiency also did not change over the length of follow-up. At 1 year, 98% of patients had no or trivial aortic insufficiency and 2% had mild aortic insufficiency. At 8 years, 100% of patients evaluated were free of any aortic insufficiency. CONCLUSIONS: The Medtronic Freestyle aortic root bioprosthesis can be used safely to replace the aortic root or aortic valve for aortic valve and aortic root pathology. Total root replacement allows optimal hemodynamic performance with no significant aortic regurgitation. Results up to 8 years show excellent survival and no signs of degeneration. Further follow-up is still needed to determine valve durability.

Aged↗
PubMed2000

Clinical fit of Procera AllCeram crowns.

STATEMENT OF PROBLEM: Color stability, strength, and accuracy of fit are the main requirements for complete-ceramic crowns. The Procera AllCeram crown system is a CAD/CAM system used to fabricate individual complete-ceramic crowns that have a dry sintered, aluminum oxide core and appear to match clinical requirements. However, there are few articles about the clinical fit of all-ceramic crowns. PURPOSE: This in vivo study measured the accuracy of fit of Procera AllCeram crowns in anterior and posterior teeth. MATERIAL AND METHODS: The clinical fit of 80 anterior and posterior Procera AllCeram crowns was evaluated by a replica technique with a light body silicone to fill space between crown and tooth and a heavy body silicone to stabilize the light body film. After removal from the artificial crowns, the replicas were segmented, and measurements of the film thickness were performed with a light microscope. RESULTS: Medians of mean marginal gap widths were between 80 and 95 microm in anterior teeth and between 90 and 145 microm in posterior teeth. Medians of maximal marginal gap widths ranged from 80 to 180 microm in anterior teeth and from 115 to 245 microm in posterior teeth. CONCLUSION: The accuracy of fit achieved by Procera AllCeram was comparable to other conventional and innovative systems.

Adult↗
PubMed1992

Treatment of an early implant failure according to the principles of guided tissue regeneration (GTR).

The present case report demonstrates the application of guided tissue regeneration (GTR) in combination with antimicrobial therapy for the treatment of an early implant failure. This treatment approach both prevented further loss of bone as well as led to the regeneration of lost bone. By means of color-converted digital subtraction images, remodelling of the tissues adjacent to the defect was documented as early as one month postsurgically. The images demonstrated "bone-fill" in the apical portion of the defect and resorptive changes at the bone crest. This case report demonstrates that combined regenerative and antimicrobial therapy may be a successful treatment approach restoring osseointegration of dental implants following loss of bone due to infection. Continuously increasing bone-fill inside the defect was documented when comparing the radiograph obtained immediately before the GTR procedure and at months 1, 2, 4, 5 and 6 of the healing period, respectively. Clinical measurement obtained at the time of the surgery and at the time of the membrane removal confirmed the radiographic evidence of bone-fill by demonstrating new tissue resistant to probing in close contact to the implant surface at the site of the previous defect. Antimicrobial therapy included an antibiotic regimen during the 1st month of healing as well as topical rinses with an antiseptic (chlorhexidine) over the entire healing period of 6 months. As a result of this treatment approach, the implant was saved and could be used as an abutment for a bridge reconstruction.

Alveolar Bone Loss↗
PubMed2000

Superficial vein valve repair with a new external valve support (EVS). The IMES (International Multicenter EVS Study).

The aim of this international multicenter trial was to evaluate the effects of a new surgical device (Gore External Valve Support-EVS) and technique for external valvuloplasty of the long saphenous vein (LSV). Patients with superficial venous disease and venous hypertension due to pure superficial venous incompetence were randomized into two treatment groups, the first treated with "conventional treatment" (ligation or stripping) and the second with external valvuloplasty with the EVS. Patients with uncomplicated varicose veins within the age range of 35-65 years were included. Incompetence with presence of functional cusps at the saphenofemoral junction (SFJ), with vein dilatation were the main inclusion criteria. The EVS comprised of a GORE-TEX patch material (including a nitinol frame) that is placed around the vein, producing a reduction in the caliber of the vein. Also the vein section becomes elliptical. These combined actions are aimed to reduce incompetence, allowing a better closure of the cusps. The EVS was placed at the SFJ after limited dissection of the vein and ligation of collaterals. The procedure was randomized as an alternative to simple ligation or stripping (according with the procedure commonly used in the center). The associated ligation of distal incompetent veins was allowed. The main outcome measures of the study were evaluated by color-duplex (morphologic findings and evaluation of reflux) and with ambulatory venous pressure (AVP) or air-plethysmography (APG). Main endpoints of the first year of the study and main subject of this report (mainly concerning safety within the first year of follow-up) were considered presence/absence of reflux; patency of the veins; mobility/function of vein cusps; occurrence of thrombosis; tolerability of the device; and increased complexity and operating time needed for the EVS. At 1 year 30 patients had been randomized (14 EVS implanted, 16 controls). Reflux was absent in all EVS patients, all treated veins were patent, and all cusps were mobile. No thrombosis had been observed and the tolerability of the device was very good. The increased complexity required by placing the EVS was limited (5-12 minutes more). In conclusion results of the first year show efficacy and tolerability of the EVS. In selected patients (superficial LSV incompetence, reflux-dilatation, functional SFJ cusps, incompetence mainly due to enlargement of the vein), the EVS could be an effective alternative to "destructive" ligation and/or stripping of the vein. Prolonged follow-up will indicate the clinical potentials of the EVS.

Adult↗
PubMed2000

The clinical performance of laboratory-fabricated crowns placed on first permanent molars with developmental defects.

BACKGROUND: Young permanent molars with developmental enamel defects commonly are treated with stainless steel crowns. However, allergic reactions to nickel and chromium have been reported by some patients. The literature contains no evaluations of alternative treatments. METHODS: In a retrospective study, the authors evaluated the clinical performance of cast gold crowns and tooth-colored composite or ceramic crowns placed on first permanent molars with developmental defects in children 6 to 8 years of age. A total of 41 molars were prepared. After crown preparation, an impression was made, and crowns of cast gold, Artglass (J.F. Jelenko & Co.) composite or Empress (Ivoclar) leucite-containing ceramic were fabricated and clinically evaluated every six months for a period ranging from two to five years postoperatively (mean three years). RESULTS: After two to five years, all crowns were fully retained. The marginal adaptation of 39 of the 41 crowns was rated excellent, and the marginal adaptation of the remaining two crowns (both gold) received acceptable ratings. In two cast gold crowns, the margins were subgingival at cementation; the remaining 39 crowns had supragingival margins at the time of luting. By the end of the second year, all margins were supragingival. All teeth were vital and asymptomatic at all evaluation points. No secondary caries was recorded. Neither gingival inflammation nor loss of vertical dimension was recorded in any case. All crowns were well-accepted by the patients and their parents. CONCLUSIONS: Laboratory-fabricated crowns can be used for the treatment of young permanent molars with developmental defects. CLINICAL IMPLICATIONS: Cast gold, composite or ceramic crowns can be used successfully to treat developmental defects of first permanent molars in children.

Child↗
PubMed2000

Circulating platelet/polymorphonuclear leukocyte mixed-cell aggregates in patients with mechanical heart valve replacement.

There is convincing evidence that cell adhesion plays an important role in cardiovascular pathology and is frequently associated to "in vivo" cellular activation. This study involves patients with mechanical heart valve replacement (MHVR patients) who have increased platelet polymorphonuclear leukocyte (PMN) reactivity. Dual-color cytometry was used to determine the expression of adhesive molecules on cellular surfaces, platelet, and PMN-bound fibrinogen as well as the presence of circulating platelet/PMN mixed-cell aggregates (MCA) in 55 MHVR patients, 49 control patients under oral anticoagulant therapy, and 22 healthy volunteers. The results demonstrated that (a) PMN from MHVR patients showed an increased PMN-bound fibrinogen (mean +/- SEM: 1,420 +/- 169 anti-fibrinogen fluorescence intensity, P= 0.0012), when compared to controls (mean +/- SEM: 747 +/- 32 anti-fibrinogen fluorescence intensity) and healthy volunteers (mean +/- SEM: 692 +/- 25 anti-fibrinogen fluorescence intensity; (b) platelet activation in MHVR patients was evidenced by the higher expression of CD62P (mean +/- SEM: 128 +/- 19 anti-CD62P fluorescence intensity, P = 0.003) compared to controls (mean +/- SEM: 65 +/- 15 and 50 +/- 10 anti CD62P fluorescence intensity) and by increased levels of platelet-bound fibrinogen (mean +/- SEM: 625 +/- 20 anti-fibrinogen fluorescence intensity, P = 0.0043 versus 496 +/- 45 and 480 +/- 30 for control patients and for healthy volunteers, respectively); and (c) the proportion of MCA in MHVR patients (15 +/- 2%) was significantly higher (P = 0.009) compared to controls (7 + 1%) and healthy volunteers (6 +/- 2%). The results indicate that the presence of stable circulating MCA represents another marker of "in vivo" PMN activation in MHVR patients.

Adult↗
PubMed2000

[Ultrasonic diagnosis of complications after bypass operations in lower extremities arteries].

After reconstructive vascular operations the patients need dynamic control and non-invasive monitoring. The purpose of the study was to reveal the potential of duplex scanning (DS) in assessment of bypasses function and diagnosis of postoperative complications. 148 patients after aorto-femoral and femoro-popliteal bypass, including patients with late postoperative complications (shunt thrombosis, stenosis or spurious aneurysm of anastomosis) were examined. Energy colored DS was performed in scans "Toshiba" SSH-140 and "Acuson" Sequoia-512. In ultrasonic diagnosis the vascular graft was imaged as a tube structure with hyperechogenic walls and distinct pulse; it was easy to detect the material of vascular graft. In examination of distal anastomosis the initial portions of efferent arteries were usually imaged distinctly. In satisfactory distal vascular bed, the shunt's blood flow did not differ from normal blood flow. In patients with multifocal lesions the spectrum of shunt's blood flow was similar to main-changed blood flow. Substantial change of blood velocity was revealed in complications (aneurysm or stenosis of anastomosis). Spurious aneurysm was imaged as a hypoechogenic pulsating formation. Thrombotic masses in aneurysm's cavity were distinctly detected at DS, unlike at angiography. In case of anastomosis insufficiency, the suture's disrupted filaments and free branch's ends could be imaged. Stenosis of anastomosis was characterized by visible lumen's stenosis, local thickening and unevenness of wall, spectrum's change and blood velocity increase. In shunt's thrombosis the DS permitted to follow the thrombed graft's path, to reveal the cause of thrombosis and to detect the condition of outflow tract. The authors regard DS as a method of choice in dynamic control for state of bypasses and arteries in patients after reconstructive operations in lower extremities arteries.

Arterial Occlusive Diseases↗
PubMed2000

Surgical left atrial appendage ligation is frequently incomplete: a transesophageal echocardiograhic study.

OBJECTIVES: This study sought to determine the incidence of incomplete ligation of the left atrial appendage (LAA) during mitral valve surgery. BACKGROUND: Ligation of the LAA to prevent future thromboembolic events is commonly performed during mitral surgery. However, success in completely excluding the appendage from the circulation has never been systematically assessed. METHODS: Using transesophageal Doppler echocardiography, we studied 50 patients who underwent mitral valve surgery and ligation of the LAA. Thirty patients were studied immediately postoperative, and 20 patients were studied 6 days to 13 years after surgery. Incomplete ligation was detected by demonstrating a color jet traversing the separation between the left atrial body and appendage. RESULTS: Transesophageal echocardiography detected incomplete LAA ligation in 18 of 50 (36%) patients. The incidence of incomplete ligation was not significantly different between patients studied immediately postoperative and patients studied at various times after surgery. Type of mitral surgery (repair vs. replacement), operative approach (sternotomy vs. port access), left atrial size or degree of mitral regurgitation did not significantly correlate with the incidence of incomplete appendage ligation. However, the power to detect a significant difference in left atrial size was only 64%. Spontaneous echo contrast or thrombus was identified within appendages in 9 of 18 (50%) patients with incomplete ligation, while 4 of these 18 (22%) patients had thromboembolic events. CONCLUSIONS: Surgical LAA ligation is frequently incomplete. The similar incidence of incomplete ligation detected immediately postoperative and at various times thereafter suggest that this results from an intraoperative phenomenon rather than from gradual dehiscence of sutures over years. The incidence of incomplete left atrial ligation was unrelated to type of surgery, surgical approach, left atrial size or degree of mitral regurgitation. Residual communication between the incompletely ligated appendage and the left atrial body may produce a milieu of stagnant blood flow within the appendage and be a potential mechanism for embolic events.

Adult↗
PubMed1990

Indications for heart valve replacement.

Proper evaluation of the patient with valvular heart disease begins with a thorough history and physical examination. Today, sophisticated noninvasive tests--especially echocardiography with color flow Doppler imaging--complement the information gained at cardiac catheterization. Information previously available only through cardiac catheterization can now be obtained from these noninvasive techniques. Serial evaluations can be performed, which are important in managing lesions of borderline hemodynamic significance and in avoiding subclinical deterioration of left ventricular contractility. Improvements in surgical expertise and intraoperative myocardial preservation allow postoperative improvement for patients with aortic stenosis and aortic insufficiency despite the presence of left ventricular systolic dysfunction. Many traditional indicators of a poor operative result in aortic insufficiency appear less reliable today. Consequently, these indicators should never be viewed in isolation or be given preeminence over clinical judgment. The long-term results following aortic valvuloplasty have been disappointing. However, mitral valvuloplasty--for technically suitable types of mitral stenosis--is an attractive alternative to surgery. Echocardiography may be helpful in selecting patients best suited for this technique. The timing of valve replacement in mitral insufficiency is made difficult by the altered loading conditions which can mask underlying contractile dysfunction. In this regard, the use of end-systolic measurements (e.g., end-systolic stress-volume ratio) more accurately characterized left ventricular contractility. When mitral insufficiency patients with left ventricular systolic dysfunction require surgery, valve repair appears superior to traditional mitral valve replacement. With valve repair, the postoperative left ventricular ejection fraction is usually higher, as left ventricular contractile reserve is better maintained.

Aortic Valve↗
PubMed1992

[Doppler echocardiography imaging of construction-induced regurgitation of technical heart valve prostheses].

The normal leakage flow in modern technical heart valve prostheses can be visualized by color-coded Doppler-echocardiography, provided that an adequate ultrasonic image quality can be achieved. Sometimes it may be difficult, however, to distinguish such a normal leakage flow from pathological regurgitation. We therefore mounted new specimens of five different types of prostheses (Bjørk-Shiley monostrut, Medtronic-Hall, Omnicarbon, Saint Jude Medical, Duromedics) into an invitro model, where the leakage flows could directly be visualized as emerging water jets. When the system was completely filled, the jets could also be registered by two-dimensional Doppler-echocardiography. For each valve, characteristic patterns for the localization of the principal jets were found. Besides the relative broad central jet in the Medtronic-Hall valve, all other jets arose mainly at the ring. They were detected at the hinges or the basis of the larger struts, respectively, and with asymmetrical mono-disc valves at the side of the smaller opening. The length and the orientation of the jets were found to change significantly with minimal variations of the position of the closing discs. This variability could be confirmed, when in a separate model the overall leakage flows were repeatedly measured. For patient examinations it seems useful to refer mainly to the localization of the jet origins. The comparison with reference values of jet-dimensions in Doppler images will rarely enable the examiner to distinguish between normal and pathological jets.

Echocardiography, Doppler↗