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Biomedical subjects

R Bonan

Publications and source records attributed to R Bonan.

At least 109 records · Page 6Linked to original sources
PubMed1986

[Dysfunction of bioprostheses. Respective value of echocardiography and of Doppler studies].

The respective diagnostic values of M mode and 2D echocardiography and pulsed and continuous wave Doppler were assessed in bioprosthetic valve dysfunction. The results of the ultrasonic investigations were compared with the operative findings and anatomo pathological appearances in 56 cases of dysfunction. Only cases with surgical confirmation were included. Doppler examinations were carried out in 13 cases. Echocardiographic imaging alone cannot resolve all the diagnostic problems posed: specific signs are rare and were only observed in one out of 7 cases of periprosthetic leak, 7 out of 10 cases of valvular stenosis and 20 out of 36 cases (55 per cent) of valve tear. In cases of valve tear, 2D echocardiography was falsely normal in 15 per cent of cases and gave equivocal results in 30 per cent of cases because it was not possible to visualise the three cusps of the bioprostheses. Doppler echocardiography does not have the same limitations and gives an immediate and accurate assessment of valve function. It is particularly useful for the diagnosis of stenosis and valve tear in which the diagnostic specificity and sensitivity attain 100 per cent (exact diagnosis in all 11 cases of valve tear). At present, continuous wave Doppler seems to be the most reliable diagnostic tool for qualitative and quantitative assessment of primary degeneration of valvular prostheses.

Adult↗
PubMed1984

Duplication of the superior vena cava: detection by radionuclide angiography.

The authors report three cases of duplication of the superior vena cava which were demonstrated by radionuclide angiography. Nuclear imaging was performed in order to demonstrate a left-to-right intracardiac shunt. Injection into the left external jugular vein demonstrated the presence of a duplication of the superior vena cava in addition to the presence of a shunt.

Adult↗
PubMed1984

Five-year clinical experience with the Omniscience cardiac valve.

Clinical data on the Omniscience cardiac valve prosthesis (sizes 19 to 31 mm) were obtained from 326 patients (155, aortic valve replacement [AVR]; 125, mitral valve replacement [MVR]; and 46, double-valve replacement) during a five-year period (650 patient-years) with 96% accountability. Mean age was 56 +/- 12 years, and 40% (130) of the patients were 61 years old or older. Thirty-one percent (101) had prior or concomitant coronary artery bypass grafting procedures, 9% (28) had a previous malfunctioning prosthesis, and 17% (57) had other cardiac surgical procedures. Eighty percent were in New York Heart Association (NYHA) Functional Class III or IV preoperatively. Early mortality was 10% (34). Five-year actuarial thrombus-free rate is 96% for patients who underwent AVR and 95% for patients having MVR. Postoperatively, 89% (172/193) were in NYHA Class I or II, and 84% (163/193) improved by at least one Functional Class. A significantly high proportion of the postoperative hematological values fall within normal ranges: red blood cell count, 94% (176/187); hematocrit, 88% (166/188); and hemoglobin, 93% (176/190). Ninety-eight percent (287/292) are free from clinical anemia. Four of the 5 patients with clinical anemia had a preoperative history of this condition. Levels of lactic dehydrogenase in 3 patients suggested the probable presence of clinically significant hemolysis, although all 3 have normal hematological values. Actuarial five-year survival for patients who underwent AVR or MVR are similar (82% and 80%, respectively), indicating satisfactory and comparable levels of safety and performance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Factors influencing thromboembolic complications in Omniscience cardiac valve patients.

Clinical data were gathered over five years (650 patient-years) for all 155 aortic valve replacement, 125 mitral valve replacement and 46 double valve replacement patients implanted with the Omniscience cardiac valve prosthesis at three North American medical cent es. Mean age was 56 +/- 12 years, 80% were preoperatively in NYHA class III or IV, and 57% had previous or concomitant cardiac surgery. Data were evaluated for the incidence of thromboembolic complications. During the late postoperative period, transient ischaemic episodes occurred in six patients (0.92% per patient-year). The five-year actuarial thrombus-free rate for serious thromboembolic complications (valve thrombosis or thromboembolism with residual effects) for aortic valve replacement patients is 96% and 95% for mitral valve replacement patients. For patients experiencing any transient or serious thromboembolic complication, 35% had a compromise of coumadin anticoagulation shortly before the thromboembolic event, 60% had a history of atrial fibrillation, and 76% a history of rheumatic heart disease. Statistically, these rates are significantly higher compared with the original valve population. The low incidence of thromboembolic complications over this five-year clinical study demonstrates a commendable degree of safety and performance for the Omniscience valve.

Actuarial Analysis↗
PubMed1984

Usefulness of digital subtraction left ventriculography in patients with ischemic heart disease: comparison with cineangiography.

Digital subtraction and computer enhancement of left ventriculography allow the injection of small amounts of contrast medium into the left ventricle. Image quality measurements of cardiac volumes, and ejection fraction and evaluation of regional wall motion were compared following digital subtraction and cine ventriculography in 30 patients undergoing coronary arteriography for suspected or proven ischemic heart disease. At concentrations of 13% to 19% (iodine contents: 2.0 to 5.0 g) meglumine sodium diatrizoate used for digital subtraction ventriculography, no alterations of ventricular pressures were noted; premature ventricular contraction and cineventriculography in 30 patients undergoing coronary arteriography for suspected wall motion by two independent observers showed complete agreement between digital and cineventriculography in 141 of 150 segments (94%), including 114 normal segments; digital ventriculography led to underestimation of four segments and to overestimation of five. Left ventricular ejection fraction and volumes calculated using both techniques correlated relatively well (ejection fraction: r = 0.86; end systolic volume: r = 0.88; end diastolic volume: r = 0.665). Thus, intraventricular injection of low concentrations of contrast medium provides good digital angiographic images and may eventually replace cine ventriculography for invasive assessment of left ventricular performance. However, ECG gating and shorter exposure times will be required for accurate measurement of ventricular volumes and ejection fractions.

Adult↗
PubMed1984

Clinical experience with ioxaglate (Hexabrix) in selective coronary arteriography.

This prospective nonrandomized study was performed to evaluate the safety and efficacy of, as well as patient tolerance for, a new low osmolality contrast medium, ioxaglate (Hexabrix), in 90 adult patients of both sexes who were referred to our cardiac catheterization laboratory for angiocardiography including selective coronary arteriography. Ioxaglate did not cause any major adverse effects; side effects were rare and mild. Hemodynamic changes were minimal, even in patients with severe coronary artery disease, and no arrhythmias were seen. The radiographic quality of angiograms was scored as good to excellent for each examination, and was equal to that of films performed using a conventional contrast medium. Ioxaglate may be the contrast medium of choice for angiocardiography, especially in patients at high risk, i.e., those with severe coronary artery disease or severe left ventricular dysfunction.

Adult↗
PubMed1983

Comparative sensitivity of exercise, cold pressor and ergonovine testing in provoking attacks of variant angina in patients with active disease.

Exercise, ergonovine and the cold pressor test have been used to provoke variant angina attacks. The sensitivity of these three tests was compared in 34 hospitalized patients with well documented, active variant angina who had recently undergone coronary arteriography. The three tests were usually performed on three consecutive days, and 28 of the 34 had the three tests within 1 week. Angina was provoked by ergonovine in all 34 patients, by exercise in 17 and by cold pressor test in only five (p less than 0.005). ST elevation developed during the ergonovine test in 32 (94%), during exercise in 10 (29%) and during the cold pressor test in only three (9%). With ergonovine, one patient had only ST depression and one had no ECG changes. During the cold pressor test two patients had pseudonormalization of abnormally negative T waves and 29 had no ECG changes. Exercise induced T-wave pseudonormalization in four patients, ST depression in nine others and no ECG changes in 11. ST elevation was more frequent with ergonovine than with either of the other tests (p less than 0.0001). ST elevation or T-wave pseudonormalization occurred more often with exercise than with cold (p less than 0.05), but both occurred less often than with ergonovine (p less than 0.0001). We conclude that the sensitivity of the ergonovine test is very high in patients with active variant angina and that exercise will provoke angina with ST elevation in about 30% of these cases. In contrast, the sensitivity of the cold pressor test is too low to be of much clinical value in the diagnosis of variant angina.

Adult↗
PubMed1982

Clinical and hemodynamic results with the Carpentier-Edwards porcine bioprosthesis.

Carpentier-Edwards bioprostheses were implanted in 605 patients, 509 of whom had a single valve replacement, and 96 of whom had a multiple valve replacement. There were 54 early deaths (8.9%) and 26 late deaths (4.3%). The five-year actuarial survival was 87% for aortic valve replacement, 83% for mitral valve replacement, and 81% for multiple valve replacement. Of the 525 survivors, all but 3 were followed for a total of 964 patient-years; 354 patients (68%) remained asymptomatic, and 95 patients (18%) were improved. The incidence of thromboembolism, endocarditis, and reoperation due to primary tissue failure of the bioprosthesis were 2.0, 1.3, and 0.1% per patient-year, respectively. The actuarial probability of being free of all valve-related complications was 93% after five years. Satisfactory hemodynamic performance of the bioprosthesis was demonstrated by postoperative studies done in 70 patients. Thus, the Carpentier-Edwards porcine valve provides good clinical improvement, with a low incidence of valve-related complications and tissue failure at five years postoperatively.

Adolescent↗
PubMed1982

Abdominal aortic angioplasty: a case report with angiographic follow-up.

Two women with typical clinical and angiographic findings of aorto-iliac occlusive disease underwent a successful percutaneous transluminal angioplasty of a severe stenosis of the lower abdominal aorta. One of them in whom control aortograms provide information on the mechanism of balloon angioplasty is reported here.

Angiography↗
PubMed1982

Hemodynamic evaluation of the Angell-Shiley porcine xenograft.

The Angell-Shiley porcine xenograft was evaluated in 48 asymptomatic subjects who underwent cardiac catheterization an average of 14 months after operation. Nineteen patients had mitral and 29 had aortic valve replacement. The average mitral valve gradient was 8 +/- 3 mm Hg and the average effective orifice area was 1.8 +/- 0.6 cm2. The average aortic valve gradient was 22 +/- 7 mm Hg and the average effective orifice area was 1.2 +/- 0.3 cm2. During supine leg exercise, the average mitral valve gradient increased to 12 +/- 4 mm Hg (p less than 0.001) and the average aortic valve gradient increased to 27 +/- 8 mm Hg (p less than 0.001) compared to findings at rest. On the basis of data obtained with a regression analysis model, there is a high probability that an Angell-Shiley aortic xenograft with a stent diameter less than 25 mm will have a postoperative effective orifice area of less than 1 cm2, and that an Angell-Shiley mitral xenograft with a stent diameter less than 30 mm will have a postoperative effective orifice area of less than 1.5 cm2. Our data suggest that the Angell-Shiley xenograft has suboptimal hemodynamic performance in stent sizes less than 30 mm in the mitral position and less than 25 mm in the aortic position.

Adult↗
PubMed1980

Ergonovine testing in a coronary care unit.

This study describes the results of ergonovine testing in 100 consecutive patients who underwent this procedure in a coronary care unit. All patients had recently undergone coronary arteriography. A bolus injection of ergonovine was administered at 5 minute intervals in the following doses (mg): 0.0125, 0.025, 0.05, 0.1, 0.2, 0.3 and 0.4. The criterion for a positive test was the appearance of S-T elevation greater than 1 mm. The test was positive in all 17 patients known to have variant angina and in 18 (40 percent) of 45 patients who had a history of chest pain judged strongly suggestive of variant angina but who had no electrocardiogram recorded during pain. Of 38 patients with a history of chest pain classified as not entirely typical of variant angina, only 1 (2.6 percent) had a positive test. Of the 64 patients with a negative ergonovine test, 47 had chest pain and 25 had nausea but none had more serious complications. Ventricular arrhythmia accompanied S-T elevation in 18 of the 36 patients with a positive test but occurred in only 4 of the 64 with a negative test (p < 0.0005). No patient needed treatment with antiarrhythmic drugs. Four of the 36 patients with a positive test had serious complications: severe transient hypotension (2 patients), recurrent episodes of angina with S-T elevation (1 patient) and a subendocardial infarction (1 patient). Thus, ergonovine testing is useful in patients with a typical clinical history of variant angina but without an electrocardiogram recorded during pain. In this study, a small but definite incidence of serious complications occurred during a positive test.

Adult↗
PubMedDate not supplied

Results of percutaneous mitral commissurotomy in patients with a left atrial appendage thrombus detected by transesophageal echocardiography.

To evaluate whether the presence of a left atrial appendage (LAA) thrombus increases the embolic risk of percutaneous mitral commissurotomy (PMC), we reviewed 240 transesophageal echocardiographic studies performed before intended PMC for mitral stenosis. We found 14 patients (5.8%) with left atrial clots, 12 located in the LAA (none detected by transthoracic echocardiography [TTE]) and two in the body of the left atrium. In the two patients who had a left atrial body thrombus, TTE did not unequivocally show the thrombus. Seven patients with an LAA thrombus underwent PMC by the double-balloon technique. The hemodynamic and echocardiographic results were comparable to those of the larger series. No embolic complications were noted either during the procedure, in the 48 hours of observation after the procedure, or at a mean follow-up of 12 months. We conclude that PMC by the double-balloon technique can be performed safely in patients with an LAA thrombus who have been given anticoagulants. Transesophageal echocardiography is still indicated before PMC because TTE is suboptimal for detection of left atrial clots.

Adult↗
PubMedDate not supplied

Effects of probucol on vascular remodeling after coronary angioplasty. Multivitamins and Protocol Study Group.

BACKGROUND: We have shown that probucol reduces restenosis after balloon angioplasty. Whether probucol acted via prevention of neointimal formation or improvement in vascular remodeling could not be addressed by angiography and required the use of intravascular ultrasound (IVUS). METHODS AND RESULTS: Beginning 30 days before angioplasty, 317 patients were randomly assigned to receive probucol, multivitamins, combined treatment, or placebo. Patients were then treated for 6 months after angioplasty. IVUS examination was performed immediately after angioplasty and at follow-up in 94 patients (111 segments). The cross section selected for serial analysis was the one at the angioplasty site with the smallest lumen area at follow-up. In the placebo group, lumen area decreased by -1. 21+/-1.88 mm2 at follow-up, and wall area and external elastic membrane (EEM) area increased by 1.50+/-2.50 and 0.29+/-2.93 mm2, respectively. Change in lumen area, however, correlated more strongly with the change in EEM area (r=0.53, P=0.002) than with the change in wall area (r=-0.13, P=0.49). Lumen loss was -1.21+/-1.88 mm2 for placebo, -0.83+/-1.22 mm2 for vitamins, -0.25+/-1.17 mm2 for combined treatment, and -0.15+/-1.70 mm2 for probucol alone (P=0.002 for probucol, P=0.84 for vitamins). Change in wall area was similar for all groups. EEM area increased by 0.29+/-2.93 mm2 for placebo, 0. 09+/-2.33 mm2 for vitamins only, 1.17+/-1.61 mm2 for combined treatment, and 1.74+/-1.80 mm2 for probucol only (P=0.005 for probucol). CONCLUSIONS: Lumen loss after balloon angioplasty is due to inadequate vessel remodeling in response to neointimal formation. Probucol exerts its antirestenotic effects by improving vascular remodeling after angioplasty.

Angioplasty, Balloon, Coronary↗