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Biomedical subjects

A Vacheron

Publications and source records attributed to A Vacheron.

At least 55 records · Page 3Linked to original sources
PubMed1996

[Cardiac evaluation in arteritis].

Coronary artery disease is very frequent and responsible for half of the death in patients with peripheral arterial disease. Clinical and electrocardiographic cardiac check-up must be systematic. The choice of coronary investigations must be guided by the clinical context. Exercise stress testing, with upper limb if necessary, must be performed in patients with suspected coronary artery disease and before high risk surgery. Dobutamine echocardiography or dipyridamole myocardial scintigraphy are justified in patients unable to performed a satisfactory exercise stress testing. Coronary angiography must be limited to patients with angina and/or recent myocardial infarction, and to patients with known coronary artery disease and high risk surgery.

Coronary Angiography↗
PubMed1996

[Rehabilitation of aged patients with bicycle ergometer after coronary surgery].

This study was undertaken to assess the contraindications to rehabilitation by exercise testing on a bicycle ergometer and the tolerance of this procedure in elderly patients recovering from coronary surgery. One hundred and eighty-four patients aged over 65 years were included (Group I). The rehabilitation program consisted of exercise testing on admission period. The results were compared with those of 146 patients aged 65 or less (Group II). Twenty-six per cent of the elderly patients had a contraindications to this type of rehabilitation compared with only 4.8% in Group II. The main contraindications were extracardiac (21.7%), including infectious causes (4.3%), neuropsychiatric (3.3%), respiratory (2.7%) and rheumatological conditions (2.2%). Cardiac causes represented only 4.3% of the contraindications. In the patients undergoing the training program, the maximum power and the duration of exercise testing increased respectively from 81 +/- 17 to 97 +/- 21 watts (+21% ; p < 10(-3)) and 7 +/- 1.7 to 9 +/- 2 minutes (+28.6%, p < 10(-3)). The change in these parameters was comparable in the other group: 94.5+/- to 118 +/- 26 watts (+24.8% ; p < 10(-3)) and 8.5 +/- 1.9 to 10.9 +/- 2.4 minutes (+28.2% ; p < 10(-3)). On the other hand, the rate-pressure product decreased slightly in the elderly patients (-5.5% ; p = 0.07, compared with -13% in Group II, p = 0.001). Complications were rare: 1.6% of temporary interruption of a session (versus 0.6%). No serious complications were observed. The authors conclude that, after coronary surgery, the majority of elderly coronary patients can participate in physical training programs on bicycle ergometers without major complications. In the absence of contraindications, patients, and even elderly patients, should be encouraged to enroll for these programs after coronary bypass surgery.

Aged↗
PubMed1995

[New techniques of interventional cardiology].

Balloon coronary angioplasty for coronary stenosis has a success rate of over 90%, but secondary restenosis occurs in 30 to 40% of the patients. In addition, long calcified, ulcerated and distal lesions cannot be treated with the balloon technique. New techniques are thus needed and are currently under clinical evaluation. Stents are metallic meshes designed as vascular prostheses to maintain the arterial lumen open. Currently, stents are indicated in case of acute coronary occlusion during the angioplasty procedure and more rarely in case of elastic recoil after dilatation. First intention stents can reduce the rate of restenosis by about one-fourth, although use is limited due to the risk of thrombosis. The rotablator has a fine elliptoid tip which rotates at 180,000 rpm. When inserted into the area of stenosis, the rotablator attacks preferentially hard resistant material and is thus indicated for calcified lesions. It should not be used in large arteries or if a thrombus is visible on the angiography. Primary success rate is 95% and recoil does not exceed 5%. But this method still is not the final solution since the rate of restenosis is 44%, and even 54% for calcified lesions. In directional arthrectomy the tip of the catheter carries a metal cylinder with a lateral window which can be positioned on the lesion. Atheromatous material is then cut off with a rotating knife and trapped in the catheter's reservoir. This new system gives results which are currently similar to those for conventional angioplasty. The potential role of transluminal laser atherectomy, an effective but costly technique, is yet to be established. These new devices offer great potential, but their impact will depend to a great extent on the experience of the cardiology team and must be evaluated in comparison with the results of the classical balloon angioplasty.

Angiography↗
PubMed1995

Bioprosthetic valve replacement in the elderly.

One hundred and ten patients aged more than 65 years (mean, 73.4; range, 65-82) underwent successful bioprosthetic valve replacement (aortic, n = 71; mitral, n = 32; both, n = 7) from 1979 to 1985. The valve was pericardial in 39 cases and porcine in 78. The mean follow-up was 75 months (total, 688 patient-years; range, 2 months to 12 years). Actuarial patient survival was 79.4% at 5 years and 55.2% at 10 years. Thirty-seven patients died: 18 from valve-related causes and 19 from other causes. Eight patients have been reoperated on for valve-related complications (1.17% per patient-year): five primary deteriorations, two paravalvular leaks and one case of endocarditis. One surgical death occurred (12.5%). Twenty-five percent of the patients were receiving anticoagulants because of atrial fibrillation, and 5.4% developed severe bleeding (3.8% patient-year). Mid-term follow-up of these patients aged more than 65 years and undergoing bioprosthetic valve replacement surgery revealed a low rate of documented primary structural deterioration (0.9% per patient-year), a low mortality rate on reoperation (12.5%) and a high mortality rate due to non valve-related causes (51.4%).

Aged↗
PubMed1995

[Thrombolysis after 75 years of age: benefits, risks, indications].

Hospital mortality of myocardial infarction in patients over 75 years of age ranges from 25 to 33% without thrombolysis. Large scale trials of intravenous thrombolytic therapy including elderly patients showed that age itself is not a contra-indication to thrombolytic therapy. However, on the one hand, contra-indications are more common, and, on the other, the characteristics of infarction in the elderly are unsuitable so that thrombolysis is rarely used: in the MITI study, only 15% of over 75 years old patients would have benefitted from this therapy. The benefits of this treatment in patients over 75 years of age have been demonstrated: they were significant in Collin's meta-analysis (hospital mortality 24.9 vs 28.8%). In a more recent analysis (FFT study) the benefits of thrombolytic therapy after 75 years of age were shown providing the delay of inclusion (< 6 hours) and classical electrocardiographic criteria (ST elevation) were respected. Moreover, age is a risk factor for cerebral haemorrhage (prevalence 2.08% in patients over 75 years of age in the GUSTO study). The results of this study showed that, despite the development of thrombolysis, age was the main risk factor for hospital mortality and was independent of other risk factors. Therefore, the indication of intravenous thrombolytic therapy in elderly patients should be considered with respect to the characteristics of infarction (delay, site, presence of subendocardial ischaemia), the contra-indication related to potential bleeding and the possibilities of performing emergency angioplasty.

Age Factors↗
PubMed1995

Cardiovascular reactivity to a new mental stress test: the maze test.

The response to the maze test was studied in 31 subjects on no medication, including seven subjects with mild essential hypertension. Beat-by-beat finger blood pressure (BP) was measured with a Finapres device. Pulse interval from which heart rate (HR) was derived was obtained from the BP signal. A period of 5 min baseline was used to define resting levels of systolic BP and HR using 20-s averaged values for the calculation of the 95% confidence limit of the two variables. The average test duration was 10 min. During this period a series of video-displayed mazes had to be solved with easy mazes preceding difficult ones. No subject had been exposed to the test before. The maximal BP elevation associated with the test was 27 mmHg. The HR response averaged 11 beats/min. Significant elevations were observed for half the test duration. No significant relationship between these two responses was observed and some subjects exhibited isolated systolic BP or HR responses. When indices obtained during this active mental stress were compared to resting values, positive correlations were observed. When the resting standard deviation (SD) of systolic BP was higher the systolic response was greater. A similar relationship was observed for HR. In addition, when the systolic BP level at rest was higher, the systolic BP reactivity index was greater. However, systolic BP or HR at baseline were not predictive of the systolic BP or HR responses. This study demonstrates the applicability of a new test to assess cardiovascular reactivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Current biological surveillance of oral anticoagulant treatment].

The prothrombin time is the coagulation time of citrated plasma in the presence of calcium and a tissue extract, thromboplastin, added in excess. The prothrombin time was historically the first method of evaluation and control of oral anticoagulation. Over the years, the different thromboplastins have changed, diversified, so affecting the result of the prothrombin ration established from the prothrombin time and a reference curve. In 1985, the International Committee on Thrombosis and Haemostasis requested that all the losts of thromboplastin have their international sensitivity index (ISI) indicated. This allowed uniformity of the results by the introduction of the INR (International Normalized Ratio) calculated by the formula: INR = (PTR)ISI, the PTR or prothrombin time ratio corresponding to the patients' prothrombin time divided by that of reference control plasma. It is, in fact, impossible to interpret the results of a prothrombin ration without knowing their expression in INR. The consequences of the absence of uniformity in the control of anticoagulant therapy are important and serious. The uncertainty concerning the degree of anticoagulation inherent in the use of a single prothrombin ratio may be the source of bleeding or thromboembolic complications. Curiously, the system based on the INR is neither generalised, nearly 10 years after its recommendation, nor adopted by the majority of practitioners. However, the stakes are high because the principal complication of oral anticoagulants remains bleeding, including the dramatic strokes. Moreover, the global mortality due to haemorrhagic complications is about 0.1 to 0.5% for treatments of short duration and much higher in prolonged therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1995

[Influence of post-infarction myocardial revascularization on the prevalence of delayed potentials].

It has been shown that the presence of ventricular late potentials is a predictive factor of ventricular tachycardia and sudden death after myocardial infarction. The value of thrombolysis in the reduction of the prevalence of ventricular late potentials is now well established. However, the effects of other modes of revascularisation is less well known and more controversial. The authors undertook a retrospective study of 139 consecutive patients undergoing coronary angiography after primary myocardial infarction. The presence of ventricular late potentials fulfilling two of the three usual criteria was sought after a revascularisation procedure. The overall prevalence of ventricular late potentials was 30.9%. This was not affected either by the site of infarction of by the single or multiple character of the coronary artery disease. In addition, the left ventricular ejection fraction was not significantly different in patients with positive ventricular late potentials compared with the others. On the other hand, revascularisation of the culprit lesion responsible for the infarction was strongly correlated with a lower incidence of ventricular late potentials (p < 10 (-5)). In particular, the different incidence of positive late potentials between the dilated (9.3%) and non-dilated group (49.2%) was statistically significant (p < 10 (-6)) without any correlation to the single or multiple character of the coronary disease. The authors discuss the different reports in the literature concerning the effects of angioplasty and coronary bypass surgery on the incidence of ventricular late potentials. Conclusion; the review of the literature shows that thrombolysis significantly reduces the incidence of late potentials after myocardial infarction and the present study suggests that angioplasty and coronary bypass surgery may also be effective.

Arrhythmias, Cardiac↗
PubMed1995

[Effects of thrombolysis on platelets and coagulation].

Rupture of an atherosclerotic plaque is often the trigger of the clotting process, via the activation of platelets which immediately adhere, aggregate and initiate coagulation on their surface. The final step of platelet aggregation involves membrane glycoprotein IIB-IIIA which has become available. Antibodies directed against this membrane receptor are currently under evaluation. They possess definite antithrombotic properties. Complex interactions between thrombolysis, leading to generation of plasmin, and platelet functions have been identified. Depending on its concentration and possibly successively, and according to in vitro experimental conditions, plasmin may be a platelet proaggregant or antiaggregant. Correlations have also been recently demonstrated between thrombolytic activity and coagulation, as, paradoxically, it has been shown that plasmin, the final step of thrombolysis, activates the intrinsic pathway of coagulation, predisposing to the formation of thrombin. This activation is involved in the efficacy of heparin therapy following intravenous thrombolysis during the acute phase of myocardial infarction. This paradoxical action of thrombolysis could also play a role in reocclusions after effective thrombolysis during the acute phase of myocardial infarction. A better understanding of the thrombolysis process and its interactions with platelets and coagulation is important in order to improve the results of this treatment, which are correlated with patient survival.

Blood Coagulation↗
PubMed1994

Coronary angioplasty in patients 75 years and older; comparison with coronary bypass surgery.

From November 1988 to May 1992, 108 patients (79 men, 29 women) 75 years or older (mean 78 +/- 3, range 75-90 years) underwent coronary angioplasty (group I: n = 62) or coronary bypass surgery (group II: n = 46). Group II patients were younger (76 +/- 2 vs 79 +/- 4, P = 0.002) and had a higher proportion of multivessel disease. The two groups were comparable with regard to the presence of unstable angina, left ventricular ejection fraction and Q wave infarction. In-hospital mortality was similar in the two groups (6.4% vs 4.3%). Complete revascularization (72% vs 47%, P < 0.05) and left anterior descending artery revascularization (100% vs 45%, P < 0.01) were more frequent in group II. Two-year infarction-free survival was similar (group I: 76 +/- 6%; group II: 79 +/- 6%) but recurrent class III or IV angina (36% vs 9%, P < 0.05) and repeat procedures (26% vs 0%, P < 0.05) were more frequent in group I.

Aged↗
PubMed1994

Usefulness of radionuclide ventriculography during transesophageal atrial pacing in the diagnosis of coronary artery disease.

Radionuclide ventriculography before, during, and after atrial transesophageal pacing was carried out in 15 patients with suspected coronary artery disease (CAD) and without myocardial infarction. All patients underwent coronary angiography. Ten patients (group 1) had a coronary lesion > 50% on at least one of the main coronary arteries. Five patients (group 2) had normal coronary arteries. Radionuclide left ventricular ejection fraction (LVEF) before pacing was 56 +/- 3% in group 1 and 59 +/- 3% in group 2 (NS). Radionuclide ventriculography during pacing was 45 +/- 4% in group 1 (P < 0.0001 vs basal in group 1) and 45 +/- 6% in group 2 (P < 0.01 vs basal in group 2, NS vs group 1 during pacing). Immediate postpacing ejection fraction did not differ in the two groups and was identical to the prepacing value. A quantitative regional wall motion analysis was performed in 105 segments. Regional radionuclide ventriculography was calculated in each segment as follows: end-diastolic counts-end-systolic counts/end-diastolic counts. The relative decrease in regional LVEF during pacing was more important in the 39 segments related to a narrowed vessel than in the 66 segments related to normal coronary artery (32 +/- 13% vs 13 +/- 10%, P < 0.0001). A more than 20% relative decrease in at least one segment during pacing occurred in 10 patients in group 1 (sensitivity 100%) and in 2 patients in group 2 (specificity 60%). In conclusion, global radionuclide ventriculography during transesophageal atrial pacing decreases in patients with and without CAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Ethics and cardiology].

The multiplication of therapeutic protocols and progressively more complex procedures, and the development of invasive procedures of interventional cardiology, have made ethics all the more important in cardiology. They should be prominent in the field of research where the primary objective is improvement of the health of the individual without abusing the dignity of the human person. The Huriet-Serusclat law of the December 20th 1988 was formulated in this spirit. However, ethics also intervene in clinical cardiological practice which should provide patients with the best treatment whilst avoiding technological excesses. Moreover, economical considerations constitute a true ethical challenge. Each individual should have access to quality health care without financial difficulties being an obstacle to this right. This equality necessitates a rational use of available resources and the taking into account of the collective interest. As an aid to decision and a barrier of protection, ethics imply constant reflection in order to supply patients with the best treatment without ignoring the interests of society.

Cardiology↗
PubMed1994

[Is the quantification of mitral valve involvement by transesophageal echography useful before percutaneous mitral commissurotomy?].

The aims of this study were to determine the value of quantifying mitral valve disease by transoesophageal echocardiography before percutaneous mitral commissurotomy (PMC) and to analyse the incidence of embolic complications during PMC since the introduction of transoesophageal echocardiography. From March 1987 to December 1991, 317 patients with pure or dominant mitral stenosis were selected by Doppler echocardiography to undergo PMC at the Montreal Institute of Cardiology. The clinical features of the first 138 patients (Group I) were the same as those of the last 179 patients (Group 2) who also underwent routine transoesophageal echocardiography the day before the procedure. A thrombus in the left atrial appendage was observed in 8 patients in Group 2 (4.4%). No embolic complications have occurred since the protocol was changed to include routine transoesophageal echocardiography, whereas 4 embolic episodes, 3 of which were fatal, occurred in patients in group 1. The indication of PMC was turned down because of angiographically severe mitral regurgitation which was underestimated by transthoracic echocardiography in 2 patients in Group 1 (1.4%) and in 3 patients in group 2 (1.6%). The mobility, thickness and degree of calcification of the valves were attributed a score from 0-4 at transthoracic and transoesophageal echocardiography. No difference was observed in the scores of mobility (2.3 +/- 0.5 versus 2.3 +/- 0.05, NS) or valve thickness (2.1 +/- 0.4 versus 2.1 +/- 0.4, NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Coronary angioplasty, a privileged method of myocardial revascularization of the elderly].

Coronary angioplasty is a myocardial revascularisation technique of choice in the elderly, avoiding the need for general anesthesia as well as the complications of thoracotomy and extracorporeal circulation. Used in a continuous series of 62 patients, it provided a 79% primary success rate in this situation, where reaching the coronary artery and penetrating the stenosis may be difficult. Femoral complications (hematoma, false aneurysm) are commoner in this age group, but appear to be beneficially influenced by the replacement of heparin by ticlopidine peri-operatively. With 24 months follow-up, the proportion of patients free of any major cardiac event and NYHA classes I and II is 66%, actuarial survival rate without infarction is 76%. These results would tend to restrict the indications for bypass after the age of 75 to cases of stenosis of the left main coronary artery, failure of angioplasty or multi-vessel atheroma with a "culprit lesion" inaccessible to dilatation.

Aged↗