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Biomedical subjects

A Vacheron

Publications and source records attributed to A Vacheron.

At least 37 records · Page 2Linked to original sources
PubMed1998

Relations of platelet Ca2+ handling and membrane microviscosity to vascular tone and restenosis after angioplasty in human coronary artery.

This study was designed to assess whether platelet Ca2+ handling or membrane microviscosity could be considered as indexes of vascular tone, or could help to predict an increased risk of restenosis after coronary angioplasty. Vascular tone was quantified in 21 patients with stable angina by the vasodilator response to sin-1 intracoronary injection in the reference coronary segment and by the importance of the acute recoil after angioplasty in the narrowed segment. The degree of restenosis was quantified by coronary angiography 6 months later. Individual values of relative sin-1-induced changes in the reference coronary diameter were positively correlated with cytosolic Ca2+ concentration in unstimulated platelets, irrespective of the extracellular Ca2+ concentration (p < 0.01). This relationship was also observed with the thrombin-evoked Ca2+ changes, measured in the absence of a Ca2+ influx (p = 0.01). No relationship was found between sin-1-induced coronary changes and membrane microviscosity evaluated by TMA-DPH and DPH anisotropies or platelet volume, or between degree of acute recoil and platelet characteristics. In conclusion, platelet Ca2+ reflects the vasodilating efficacy in response to sin-1, but cannot help to predict restenosis after coronary angioplasty.

Adult↗
PubMed1998

Relation between successful late coronary angioplasty of an occluded, infarction-related artery and lower prevalence of ventricular late potentials.

BACKGROUND: The effect of mechanical reperfusion of the infarction-related artery on ventricular late potentials (VLP) continues to be debated. OBJECTIVE: To assess the influence of successful late coronary angioplasty on the prevalence of VLP after acute myocardial infarction (AMI). METHODS: We studied 113 consecutive patients (97 men, 16 women, mean age 57 +/- 10.8 years) in whom the infarction-related artery was occluded (thrombolysis in myocardial infarction score 0 or 1) at the time of the initial coronary arteriography 10.9 +/- 6.4 days after a first AMI. Successful late angioplasty of the infarcted artery was performed in 55 patients a mean of 11.5 +/- 7.2 days after AMI. The remaining 58 patients received a conservative treatment. Signal-averaged electrocardiograms (SAECGs) were recorded 25 +/- 10.2 days after AMI. Multivariate analysis was undertaken to assess the influence of late coronary angioplasty with respect to age, sex, infarction site, angiographic ejection fraction, extent of diseased coronary arteries, thrombolysis and time of recording the SAECG. RESULTS: The overall prevalence of VLP was 27%. It was greater in patients without than in those with angioplasty (40% compared with 15%, P = 0.017). Multivariate analysis demonstrated that successful angioplasty (odds ratio 3.2; P = 0.019) and ejection fraction >0.4 (odds ratio 5.1; P = 0.0051) were the strongest independent predictors of an absence of VLP. 'Non-inferior' myocardial infarction was also correlated with the absence of VLP (odds ratio 2.6), but with borderline significance (P = 0.053). CONCLUSION: When performed in an occluded, infarction-related artery, successful late coronary angioplasty contributes to a significant decrease in the prevalence of VLP.

Aged↗
PubMed1998

[Staphylokinase].

Myocardial infarction is due to thrombotic occlusion of a coronary artery. Current thrombolytic agents have demonstrated their major value by inducing a significant reduction of mortality, but they nevertheless present certain limits: 1) excellent arterial patency is obtained in only about 50% of cases; 2) reocclusions persist in 5 to 10% of cases; 3) very severe complications, such as cerebral haemorrhages, have not disappeared (about 0.5% of cases). There is therefore a large field of action for development of the optimal thrombolytic agent. Research concerning staphylokinase, classified among third generation thrombolytic agents, is therefore situated in this context. Staphylokinase is a protein known to possess profibrinolytic properties for more than four decades, but has been the subject of renewed interest over recent years. This article reviews the characteristics, mechanism of action and fibrinolytic properties of staphylokinase. It recalls the main results obtained in animal models and summarizes the main clinical trials in man.

Animals↗
PubMed1997

Effect of nadroparin, a low-molecular-weight heparin, on clinical and angiographic restenosis after coronary balloon angioplasty: the FACT study. Fraxiparine Angioplastie Coronaire Transluminale.

BACKGROUND: Experimental studies suggest that the antiproliferative effect of heparin after arterial injury is maximized by pretreatment. No previous studies of restenosis have used a pretreatment strategy. We designed this study to determine whether treatment with nadroparin, a low-molecular-weight heparin, started 3 days before the procedure and continued for 3 months, affected angiographic restenosis or clinical outcome after coronary angioplasty. METHODS AND RESULTS: In a prospective multicenter, double-blind, randomized trial, elective coronary angioplasty was performed on 354 patients who were treated with daily subcutaneous nadroparin (0.6 mL of 10,250 anti-Xa IU/mL) or placebo injections started 3 days before angioplasty and continued for 3 months. Angiography was performed just before and immediately after angioplasty and at follow-up. The primary study end point was angiographic restenosis, assessed by quantitative coronary angiography 3 months after balloon angioplasty. Clinical follow-up was continued up to 6 months. Clinical and procedural variables and the occurrence of periprocedural complications did not differ between groups. At angiographic follow-up, the mean minimal lumen diameter and the mean residual stenosis in the nadroparin group (1.37+/-0.66 mm, 51.9+/-21.0%) did not differ from the corresponding values in the control group (1.48+/-0.59 mm, 48.8+/-18.9%). Combined major cardiac-related clinical events (death, myocardial infarction, target lesion revascularization) did not differ between groups (30.3% versus 29.6%). CONCLUSIONS: Pretreatment with the low-molecular-weight heparin nadroparin continued for 3 months after balloon angioplasty had no beneficial effect on angiographic restenosis or on adverse clinical outcomes.

Adolescent↗
PubMed1997

Effect of pravastatin on angiographic restenosis after coronary balloon angioplasty. The PREDICT Trial Investigators. Prevention of Restenosis by Elisor after Transluminal Coronary Angioplasty.

OBJECTIVES: This study sought to determine whether pravastatin affects clinical or angiographic restenosis after coronary balloon angioplasty. BACKGROUND: Experimental data and preliminary clinical studies suggest that lipid-lowering drugs might have a beneficial effect on restenosis after coronary angioplasty. METHODS: In a multicenter, randomized, double-blind trial, 695 patients were randomized to receive pravastatin (40 mg/day) or placebo for 6 months after successful balloon angioplasty. All patients received aspirin (100 mg/day). The primary angiographic end point was minimal lumen diameter (MLD) at follow-up, assessed by quantitative coronary angiography. A sample size of 313 patients per group was required to demonstrate a difference of 0.13 mm in MLD between groups (allowing for a two-tailed alpha error of 0.05 and a beta error of 0.20). To allow for incomplete angiographic follow-up (estimated lost to follow-up rate of 10%), 690 randomized patients were required. Secondary end points were angiographic restenosis rate (restenosis assessed as a categoric variable, > 50% stenosis) and clinical events (death, myocardial infarction, target vessel revascularization). RESULTS: At baseline, clinical, demographic, angiographic and lipid variables did not differ significantly between groups. In patients treated with pravastatin, there was a significant reduction in total and low density lipoprotein cholesterol and triglyceride levels and a significant increase in high density lipoprotein cholesterol levels. At follow-up the MLD (mean +/- SD) was 1.47 +/- 0.62 mm in the placebo group and 1.54 +/- 0.66 mm in the pravastatin group (p = 0.21). Similarly, late loss and net gain did not differ significantly between groups. The restenosis rate (recurrence > 50% stenosis) was 43.8% in the placebo group and 39.2% in the pravastatin group (p = 0.26). Clinical restenosis did not differ significantly between groups. CONCLUSIONS: Although pravastatin has documented efficacy in reducing clinical events and angiographic disease progression in patients with coronary atherosclerosis, this study shows that it has no effect on angiographic outcome at the target site 6 months after coronary angioplasty.

Adult↗
PubMed1997

[Analysis of frequency-dependence of ventricular repolarisation by the Holter method in young adults. Influence of the autonomic nervous system on the rate-dependence of QT].

UNLABELLED: Adaptation of ventricular repolarization duration to heart rate provides additional information to the static duration of QT interval. METHODS: QT/RR relation and his slope were determined using 24-hour ECG recordings from 17 young male normal volunteers (mean age: 22 +/- 3 years). In order to determine the influence of the autonomic nervous system on the rate-dependence of QT, the authors compared the slopes obtained from recordings during the day and the night. Then, the respective rate-dependences of the entire QT interval (QTe) and its initial subdivision (QTa) and their correlations with parameters of heart rate variability were studied. RESULTS: the QTa/RR and QTe/RR relations were constantly linear, with very significant regression coefficients. The daytime QTa/RR and QTe/RR slopes were significantly steeper than the nighttime ones (0.138 +/- 0.035 vs 0.108 +/- 0.040, p < 0.05 for QTe/RR, 0.160 +/- 0.069 vs 0. 108 +/- 0.055, p < 0.01 for QTa/RR). The early part of QT showed a stronger rate-dependence than the global QT, but only at daytime (0.160 +/- 0.069 vs 0.138 +/- 0.035, p < 0.05). No correlation was found between rate dependences and heart rate variability parameters. CONCLUSION: the authors demonstrate, from ambulatory ECG recordings, the influence of the autonomic nervous system on the rate-dependence of ventricular repolarization in normal young adults, and a difference in rate-dependence between the entire QT interval and its initial part QTa, due to differences in autonomic nervous system tone. This heterogeneity should be taken to account in the study of pathological changes or drugs effects on ventricular repolarization.

Adolescent↗
PubMed1997

[Anti-streptokinase antibodies].

The use of thrombolytics has significantly improved the management of patients with acute myocardial infarction but available molecules remains imperfect: restoration of normal coronary patency in about half the cases, risks of reocclusion, risk of bleeding. Streptokinase (SK), which is the least expensive agent, has disadvantages as do the other thrombolytics. SK, an immunogenic bacterial protein, has another feature: administration of SK leads to an immunitory response with the production of specific anti-streptokinase antibodies. These anti-streptokinase antibodies may interfere with the future administration of a compound containing SK either by inducing an allergic response or by neutralising the SK and making it ineffective. Moreover, anti-streptokinase antibodies, the result of previous streptococcal infections, are present in the circulation. Although the prevalence of anti-streptokinase antibodies in the general population, especially coronary patients at risk of myocardial infarction, is not well known and their potentially harmful effects are even less well known. In particular, the platelet aggregant effect in vitro of these antibodies in the presence of SK was not taken into account in the trials studying the influence of anti-streptokinase antibodies in the results of thrombolysis by SK. The anti-lytic effect of anti-streptokinase antibodies is well documented. For this reason, it is not recommended to readminister SK in patients who have previously been thrombolysed with a product containing SK.

Antibodies, Bacterial↗
PubMed1997

[Factors determining the improvement of effort capacity in aged patients with coronary disease during the 1st month following coronary surgery].

UNLABELLED: In order to determine the predictive factors of improvement of the physical capacity of elderly coronary patients following coronary surgery, we retrospectively analysed the data of 204 consecutive patients over the age of 65 years (181 men, 23 women, mean age: 70 +/- 4.4 years), admitted for a phase II active training programme. METHODS: The patients were divided into two groups as a function of the rate of improvement of the duration of the stress test: group A (improvement greater than or equal to 25%; n = 108) and group B (less than 25%; n = 96). Comparison of these 2 groups by multivariate analysis identified predictive factors of improvement among seven variables: age, sex, excess weight, haemoglobin, number of training sessions, duration of baseline stress test, interval between bypass graft and start of training. RESULTS: After training, the duration of the stress test and the maximal power were improved by 26.5% and 24%, respectively: 7.1 +/- 1.7 vs 8.9 +/- 2.3 minutes (p = 0.0001); 79 +/- 18.4 vs 97.8 +/- 23.7 watts (p = 0.0001). 34 (1.4%) of the 2,396 training sessions were temporarily interrupted, because of muscle fatigue in 47% of cases. Patients who had readapted before the 15th postoperative day presented fewer incidents: 4.3% vs 13.1%; NS. Only three variables appeared to be predictive of improvement of physical capacity: a duration less than 6 minutes on the baseline stress test (p = 0.0003), more than 12 training sessions (p = 0.0029) and age less than or equal to 70 years (p = 0.014). CONCLUSION: In elderly subjects undergoing coronary surgery, the improvement of physical capacity is greater the lower the baseline effort, the lower the age-group and the greater the number of training sessions. In the absence of contraindication, it appears justified to include elderly coronary patients in training programmes, even when their baseline effort level appears to be low. This training can be started by the 15th postoperative day.

Age Factors↗
PubMed1996

Assessment of reversible dyssynergic segments after acute myocardial infarction: Dobutamine echocardiography versus thallium-201 single photon emission computed tomography.

Only a moderate degree of concordance has been reported between stress-redistribution-reinjection thallium-201 single photon emission computed tomography (SPECT) and dobutamine echocardiography for the identification of myocardial viability after acute myocardial infarction. SPECT with rest-reinjection performed 4 hours after exercise testing and digitized two-dimensional (2-D) ultrasound reconstruction of the left ventricle at baseline and after low-dose dobutamine (5 to 10 microg/kg/min) infusion were compared in 50 patients > or = 8 days (12 +/- 7 days) after acute myocardial infarction. Five patients were excluded because of technically inadequate echocardiograms. Both SPECT and dobutamine echocardiography were assessed in a 16-segment model and interpreted in the remaining 45 patients. Digitized 2-D reconstruction of the left ventricle in each wall motion was scored from 1 (normal) to 4 (dyskinesia). Myocardial viability was identified on ultrasound wall-motion improvement of one or more grades from baseline to echocardiography performed > or = 30 days (60 +/- 41 days) after systematic revascularization procedure of the infarct-related artery. Reversible defect under thallium-201 SPECT and wall-motion improvement under dobutamine echocardiography were concordant in 163 (69 percent) of the 235 baseline dyssynergic segments and in 30 (67 percent) patients. Myocardial viability was identified after angioplasty (n=37) or surgery (n=8) in 29 patients and 109 segments. Positive and negative predictive values per patient in the diagnosis of myocardial viability were 86 percent and 57 percent, respectively, for stress thallium-201 SPECT with reinjection, and 100 percent and 62 percent for dobutamine echocardiography. Positive and negative predictive values per segment were 80 percent and 69 percent for the isotopic method and 91 percent and 70 percent for dobutamine echocardiography. We conclude that dobutamine echocardiography and stress thallium-201 SPECT with reinjection have similar accuracies to identify myocardial viability after acute myocardial infarction, with excellent positive but relatively low negative predictive values.

Adrenergic beta-Agonists↗
PubMed1996

Talking effect and white coat phenomenon in hypertensive patients.

Both white coat effect (the tendency of blood pressure to rise during a medical visit) and talking effect were analyzed in 42 patients with essential hypertension. Blood pressure was measured during the clinic visit and over the subsequent 24-hour ambulatory period, with the physician performing 49 +/- 4 measurements for each patient. Three silent periods and two talking periods (stress and relaxation) were randomly allocated in a crossover design and studied, using analysis of variance. During the initial 11-minute silent period, systolic/diastolic blood pressures increased by 6 mm Hg/5 mm Hg. During the subsequent talking periods, these variations were significantly greater: +22 mm Hg/+17 mm Hg. Measures of systolic/diastolic blood pressure were higher during stressful talking than during relaxed talking. The talking and its emotional contents seemed to explain 70% of the white coat phenomenon. To minimize the white coat phenomenon in the clinic, physicians, nurses, and clinicians are advised to measure blood pressure during an initial period of silence.

Communication↗
PubMed1996

[Does gender affect long-term results of coronary angioplasty in patients with multivessel disease?].

Multivessel coronary angioplasty, defined as angioplasty of 2 or 3 main coronary vessels performed during the same procedure, was performed in 203 selected patients between 1981 and 1986. The results in men (n = 159, group I) were compared with those in women (n = 44, group II). The angiographic appearances were comparable in the two groups, but the women were older, more often hypertensive and diabetic, and more symptomatic than the men (82% vs 57% in grades 3 or 4 of the Canadian Cardiovascular Society (CCS) Classification; p < 0.009). Complete revascularisation with angioplasty of all stenoses > 50% was attempted during the same session. The primary success rate per lesion was comparable in the two groups (90% in men, 93% in women; NS), as was the number of segments successfully dilated per patient (2.2 +/- 0.7 in group I and 2.2 +/- 0.8 group II; NS). Angioplasty was complicated by myocardial infarction and/or emergency coronary bypass surgery in 11 men and 2 women (NS). Clinical follow-up was obtained for an average of 71 +/- 22 months in the men and 70 +/- 22 months in the women in 96% of cases. The global seven year survival rate without recurrent infarction or cardiovascular death was 81% in men and 83% in women (NS). The number of repeat revascularisation procedures was comparable in the two groups (46% in women and 43% in men; NS) as was the number and duration of hospital admissions during follow-up (8.4 +/- 12.3 days in the women and 6.7 +/- 8.4 days in the men; NS). The functional status at the end of follow-up was the same in the two groups with 84% of men and 81% of women being asymptomatic or grade 1 of the CCS classification. The authors conclude that the long-term results of multivessel angioplasty are good and comparable in men and women. This revascularisation procedure should be considered as an alternative to surgery in women and men.

Actuarial Analysis↗
PubMed1996

[Treatment of refractory unstable angina by transluminal coronary angioplasty].

The aim of this retrospective study was to assess the value of percutaneous transluminal coronary angioplasty (PTCA) in unstable angina refractory to maximal medical therapy. The results of this procedure in these patients were compared with the results in unstable angina controlled by medication before angioplasty. Between january 1987 and january 1993, 30 patients underwent emergency PTCA for refractory unstable angina (group I). The clinical and angiographic features were compared with these of 30 patients with medically controlled unstable angina, paired for age and dilated artery (group II). The left ventricular ejection fraction was compared in the two groups (58 and 57%). The morphology of the coronary lesions according to the Ambrose classification, TIMI grading, number of lesions, degree of stenosis and severity of coronary calcification were comparable in the two groups. However, in group I, there was a significantly higher number of filling defects (30% compared with 10%, p = 0.05) and a greater number of per-PTCA complications, especially acute occlusions (23 compared with 13%, NS) with 3 deaths and 2 myocardial infarctions (compared with 1 death and 2 myocardial infarctions in group II). At long term, the restenosis, myocardial infarction and secondary death rates were comparable in the two groups with an average follow-up of 27 +/- 18 months. The poor prognosis of refractory unstable angina is therefore related to morbidity in the hospital period. These results confirm the physiopathological importance of the thrombotic process in unstable angina; the presence of "filling defect" is a poor prognostic factor associated with resistance to medical therapy. Coronary angioplasty is a valuable technique in this context but carries a higher risk of acute complications which can be reduced by an optimal platelet antiaggregant and anticoagulant therapy and in future by the use of new antithrombotic agents.

Angina, Unstable↗
PubMed1996

[Tolerance of amlodipine in left ventricular dysfunction of ischemic origin].

The aim of this study was to assess the effects of amlodipine on left ventricular function at rest and on effort, at least 30 days after myocardial infarction. The 30 patients included in the study had resting isotopic ejection fractions of 40 to 60%. At inclusion and after 15 days treatment with 10 mg of amlodipine, the patients underwent exercise stress testing with a standard Bruce protocol and resting and exercise isotopic left ventricular ejection fractions were measured. The association of betablockers was allowed but vasodilator therapy was prohibited. During the second exercise stress test, the duration of exercise increased (437 +/- 167 to 518 +/- 154 s; p < 0.002) and the work level rose from 140 +/- 56 to 169 +/- 60 Watts; p < 0.04. The number of electrically positive tests did not change significantly (33 vs 26.7%; NS). The resting ejection fraction did not increase after 15 days treatment with amlodipine (47.4 +/- 6.7 vs 48.3 +/- 8.9%; NS). Similar results were observed with respect to the exercise ejection fraction (51.4 +/- 10.4 vs 52.6 +/- 8.6%; NS). These patients may however be divided into two subgroups. In the first subgroup of 10 patients, the resting ejection fraction rose by more than 5% with amlodipine whereas the exercise ejection fraction remained unchanged (54.4 +/- 7.7% vs 54.5 +/- 7.5% with amlodipine). In the second subgroup of 20 patients, the resting ejection fraction decreased slightly with amlodipine (48 +/- 6.9% vs 45.3 +/- 8%; p = 0.04) but increased significantly on exercise (45.3 +/- 8% vs 51.7 +/- 9.1%; p < 0.0002). Therefore, amlodipine, a new generation calcium antagonist, does not induce any deleterious effect after myocardial infarction with mild left ventricular dysfunction.

Adult↗
PubMed1996

[Calcium inhibitors and post-infarction].

Although the value of beta-blockers in secondary prevention of infarction has been largely demonstrated, the role of calcium channel blockers has remained controversial for a long time. However, some subgroups of infarction may benefit from these drugs: limited infarction, without Q wave, infarction without left ventricular dysfunction. The beneficial effect is essentially observed with bradycardic calcium channel blockers (diltiazem, verapamil) and provided treatment is deferred for several days after the acute phase of myocardial necrosis. In the light of the results of the DAVIT II and CRIS studies, verapamil is a reasonable alternative to beta-blockers in secondary prevention of infarction, when beta-blockers are contraindicated especially because of asthma or chronic respiratory failure. It can obviously be associated with other treatments with a demonstrated value in post-infarction (especially aspirin and angiotensin converting enzyme inhibitors).

Calcium Channel Blockers↗