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Biomedical subjects

C Le Feuvre

Publications and source records attributed to C Le Feuvre.

At least 37 records · Page 2Linked to original sources
PubMed2000

Detection of coronary restenosis by exercise electrocardiography thallium-201 perfusion imaging and coronary angiography in asymptomatic patients after percutaneous transluminal coronary angioplasty.

Noninvasive detection of restenosis in patients remaining asymptomatic after percutaneous transluminal coronary angioplasty (PTCA) remains a major clinical problem. The value of exercise electrocardiography (ECG) and exercise-redistribution thallium-201 single-photon emission computed tomography (SPECT) in detecting restenosis in such patients remains uncertain. Discordances between these tests and coronary angiography is a common situation. We studied 179 consecutive patients remaining asymptomatic after successful PTCA (208 vessels), who underwent 6 +/- 2 months of exercise ECG, SPECT, and coronary angiography. We sought to assess the diagnostic value of the noninvasive tests compared with coronary angiography, and identify the determinants of discordances between the tests. Restenosis (diameter stenosis >50%) was detected in 39% of patients and in 37% of vessels. The overall sensitivity, specificity, and accuracy for exercise ECG and SPECT in detecting restenosis in individual vessels were, respectively, 53% versus 63% (p = 0.06), 59% versus 77% (p = 0.0001), and 57% versus 72% (p = 0. 0001). On multivariate analysis, positive exercise ECG was associated with higher heart rate response (p = 0.02), incomplete revascularization (p = 0.004), and angiographic restenosis (p = 0. 03), whereas positive SPECT was associated with incomplete revascularization (p = 0.02), infarct-related artery PTCA (p = 0.01), and angiographic restenosis (p = 0.0001). Accuracies of the 2 tests were not significantly different in patients with incomplete revascularization or PTCA of an infarct-related vessel. Overall, SPECT is more accurate than exercise ECG in detecting asymptomatic restenosis. Nevertheless, incomplete revascularization and PTCA of an infarct-related artery could cause reversible perfusion defects regardless of restenosis, reducing the diagnostic value of SPECT in such patients.

Angioplasty, Balloon, Coronary↗
PubMed2000

Influence of SIN-1 on platelet Ca2+ handling in patients with suspected coronary artery disease: ex vivo and in vitro studies.

The 3-morpholinosydnonimine (SIN-1) generates both nitric oxide (NO) and superoxide anion (O2-). It elicits dose-dependent vasodilation in vivo, in spite of the opposite effects of its breakdown products on vascular tone and platelet aggregation. This study was designed to investigate the influence of intravenous SIN-1 injection on platelet Ca2+ handling in patients undergoing coronary angiography. SIN-1 administration reduced cytosolic [Ca2+] in unstimulated platelets by decreasing Ca2+ influx. It attenuated Ca2+ mobilization from internal stores evoked by thrombin or thapsigargin. In vitro studies were used as an approach to investigate how simultaneous productions of NO and O2- from SIN-1 modify thrombin- or thapsigargin-induced platelet Ca2+ mobilization. Superoxide dismutase, the O2- scavenger, enhanced the capacity of SIN-1 to inhibit Ca2+ mobilization but catalase had no effect. This suggests that the effects of SIN-1 on platelet Ca2+ handling resemble those of NO, but are modulated by simultaneous O2- release, independently of H2O2 formation.

Angina Pectoris↗
PubMed2000

[Coronary angioplasty in hemodialysis patients].

The results of balloon coronary angioplasty are very disappointing in haemodialysis patients because of the high restenosis rate. On the other hand, the use of stents in this population had not previously been assessed. This retrospective study compared 63 coronary patients on haemodialysis with a référence group of 63 paired patients with respect to gender, age, and the necessity or not of stent implantation. There was a higher frequency of hypertension (79 vs 39%) and of hypertriglyceridaema (22 vs 8%) in the haemodialysis group than in the controls. However, there was no significant difference with respect to primary success rate of angioplasty (92 and 89% respectively), nor to the development of early cardiovascular complications (4% and 1.9% respectively). After a two-year follow-up, there was no significant difference in the restenosis rate in the haemodialysis patients (33%) compared with the controls (25%). Nevertheless, the mortality rate at 2 years was higher in the dialysis group (15%) compared with the reference group (3.5%, p = 0.03). However, this mortality rate was lower than that reported in the literature in haemodialysis patients after balloon angioplasty. Therefore, haemodialysis does not increase the risk of restenosis when an optimal angiographic results is obtained either by balloon angioplasty or by angioplasty with stenting. Coronary angioplasty is a safe and effective method of revascularisation in coronary haemodialysis patients when the lesions are accessible to stenting.

Aged↗
PubMed1999

The heparin management test: a new device for monitoring anticoagulation during coronary intervention.

Whole blood coagulation analysers are widely used during percutaneous coronary interventions. The precise degree of anticoagulation in patients is important in this setting. The aim of this investigation was to compare the results obtained with ACT (Hemochron) and HMT, the Heparin Management Test (TAS) in patients undergoing percutaneous coronary interventions. Patients (n = 100) were enrolled prospectively. Each patient received 10,000 units of heparin. At the end of the procedure, the mean ACT was 284+/-31 seconds and the mean HMT was 292+/-33 seconds. The correlation between the two methods was highly significant (r = 0.64, p<0.001). The HMT correlates well with ACT values in patients undergoing percutaneous coronary interventions. Its use in the management of these patients should be considered.

Angina, Unstable↗
PubMed1999

[New thrombolytic agents in myocardial infarction].

Myocardial infarction is the result of thrombotic coronary artery occlusion. Although present-day thrombolytics have major value by increasing the frequency of reopening of arteries responsible for myocardial infarction, by preserving myocardial function and, thereby, significantly reduce mortality. Nevertheless, they are subject to the following limitations: 1) excellent arterial partency is only obtained in 50% of cases: 2) reocclusion occurs in 5 to 10% of cases; 3) severe complications such as cerebral haemorrhage are observed in about 0.5% of cases. Therefore, the search to improve thrombolytic agents is intense. This article reports the recent advances in concept and production of new thrombolytic agents. The most recent results concern the production of mutants of T-PA (tissue plasmogen activator). Of these mutants, the reteplase (r-PA) has already received authorization for its commercialisation. Other t-PA mutants under development (phase 3) include TNK-t-PA and lanoteplase. Over the last few years, there has been renewed interest in staphylokinase. The results of the initial clinical trials with this agent have also been reported. Paradoxically, the mode of action of thrombolytic agents has an inherent pro-thrombotic effect. This explains some of the interest for anti-thrombotic agents as an adjuvant treatment of thrombolysis. The initial results of the association of thrombolytics with new glycoprotein IIb/IIIa platelet inhibitors and anti-thrombin agents are reported.

Coronary Disease↗
PubMed1998

Comparison of activated clotting times to heparin management test for adequacy of heparin anticoagulation in percutaneous transluminal coronary angioplasty.

The aim of this study was to compare the activated clotting time (ACT) obtained with the Hemochron device and the Heparin Management Test (HMT) on a new automated whole-blood coagulometer, the Thrombolytic Assessment System, in patients undergoing angioplasty. Fifty patients undergoing balloon angioplasty were prospectively enrolled. The mean ACT after a 10,000 unit bolus of heparin was 283 +/- 39 sec at the end of the procedure. The mean HMT after 10,000 units of heparin was 286 +/- 31 sec at the end of the procedure in the same patients. The correlation between the two methods was significant (r = 0.6; P < 0.01). The HMT appears to correlate well with standard values obtained with the Hemochron ACT monitor in patients undergoing percutaneous transluminal coronary angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed1998

Pre-treatment with elastase improves the efficiency of percutaneous adenovirus-mediated gene transfer to the arterial media.

The endothelium and internal elastic lamina (IEL) appear to be the main barriers to adenovirus-mediated gene transfer to medial smooth muscle cells (SMC). The present randomized study tested whether controlled incubation with elastase enhanced the efficiency of catheter-based gene transfer to medial SMC by adenoviral vectors. After an initial safety dose ranging study, rabbits underwent balloon abrasion of the iliac endothelium followed by local incubation of either elastase (2 x 10(-7) IU over 5 min) or saline using a double balloon catheter (DBC). Then, adenoviral vectors (5 x 10(9) p.f.u.) carrying Cmv-Luc or RSV-beta gal reporter genes were instilled for 30 min. Three days later, the number of medial SMC expressing lacZ was increased in the elastase-treated arteries compared with saline-treated arteries (7.2 +/- 2.5 versus 2.3 +/- 0.9 cells per section, P = 0.003). Likewise, the amount of luciferase protein product was increased (70 +/- 32 versus 36 +/- 15 pg luciferase/mg tissue, P = 0.03). No vessel enlargement, light or electron microscopic evidence of injury or inflammation was seen in elastase-treated arteries up to 7 weeks. Preincubation with elastase increased transduction efficiency of catheter-based gene delivery of replication-defective adenoviral vectors to rabbit iliac arteries without detectable arterial damage.

Adenoviridae↗
PubMed1998

Arterial response to mild balloon injury in the normal rabbit: evidence for low proliferation rate in the adventitia.

BACKGROUND: The role of constrictive remodeling, spasm and proliferation (particularly in the adventitia) in the genesis of chronic lumen narrowing after balloon injury remains under debate. This study analyzed the time course of these components following mild injury in normal arteries. METHODS: Iliac injury was induced by balloon overstretch in 32 rabbits, sacrificed at timed intervals from day 3 to 28. Angiographic response to nitrates, morphometric, immunohistochemical and biochemical analysis were performed at each time point. RESULTS: Quantitative angiography showed a decrease in lumen diameter and no change in response to nitrates over time. On morphometric analysis, remodeling was usually constrictive, appeared as early as day 3 and was responsible for 69+/-14% of the histologic lumen area stenosis at day 28. Constrictive remodeling was correlated negatively to intimal hyperplasia (r= 0.51, P< 0.002) and positively to the lumen area stenosis (r= 0.92, P< 0.0001). Macrophages (labeled by anti-RAM 11 antibodies) were very rare at all time points. Immunohistochemistry identified a high rate of proliferating smooth muscle cells in the media (13+/-7%) and intima (49+/-8%) at day 7, which decreased rapidly. Proliferating cells in the adventitia were rare (3+/-2% at day 7). The number of proliferating cells was time-dependent (r= 0.82, P< 0.0001) and related to cyclin A mRNA measured by reverse transcription-polymerase chain reaction (r= 0.84, P< 0.0001). CONCLUSIONS: In this model, luminal loss was mainly caused by constrictive remodeling rather than intimal hyperplasia. Constrictive remodeling appeared early and was not time-dependent. Macrophages, spasm and adventitial proliferation did not contribute to this constrictive remodeling.

Angioplasty, Balloon↗
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

[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

Safety of slow pathway ablation in patients with atrioventricular node reentrant tachycardia and a long fast pathway effective refractory period.

Radiofrequency catheter ablation is an accepted primary therapy for atrioventricular (AV) node reentrant tachycardia (AVNRT). There is concern that slow pathway ablation in patients with a long anterograde fast pathway effective refractory period (ERP) may potentially impair subsequent node conduction. Eighteen patients (14 women; age 53 +/- 20 years) with symptomatic AVNRT, whose fast pathway ERP at baseline was > or = 500 ms, underwent slow pathway ablation. Their outcome was compared with 24 consecutive control patients (17 women; age 42 +/- 17 years) who underwent ablation for AVNRT whose fast pathway ERP at baseline was <500 ms (controls). Slow pathway ablation was successful in 16 patients (90%). One patient had inadvertent fast pathway ablation. In a second patient the slow pathway could not be ablated because of recurrent transient AV block. Ablation was successful in all patients in the control group. Transient AV block related to current application occurred in 4 patients (22%) versus 1 control (4%) (p = 0.07). After ablation, the AV node refractory period increased in patients (368 +/- 68 to 428 +/- 92 ms, p = 0.02) and in controls (282 +/- 35 to 336 +/- 55 ms, p <0.0001), but the fast pathway ERP shortened in both groups (patients: 558 +/- 63 to 428 +/- 92 ms, p = 0.003; controls: 356 +/- 53 to 336 +/- 55 ms, p = 0.05). Furthermore, the slope of the regression line relating to shortening of the fast pathway ERP to the baseline ERP was markedly steeper in patients compared with controls (1.9 vs 0.4, p <0.0001). The shortening of the fast pathway ERP was greater in patients compared with controls (122 +/- 130 vs 21 +/- 50 ms, p = 0.001). During a mean follow-up of 18 +/- 11 months, 1 patient with severe coronary artery disease died suddenly 2 years after ablation. There was no recurrence of clinical tachycardia, and none of the patients developed symptoms of bradycardia or required permanent pacing. Thus, slow pathway ablation in patients with AVNRT and a long fast pathway ERP is safe and effective.

Adult↗
PubMed1997

Utility of full electrophysiological study before accessory pathway ablation in Wolff-Parkinson-White syndrome.

BACKGROUND: A single catheter technique has been described for ablation in patients with Wolff-Parkinson-White syndrome. It is unknown how often omission of a standard electrophysiological study would lead to misdiagnosis based on an assumption that the manifest accessory pathway is responsible for clinical tachycardia. OBJECTIVES: To examine the contribution of the standard electrophysiological study versus an abbreviated, single catheter approach in patients with Wolff-Parkinson-White syndrome and an overt delta wave electrocardiographically. PATIENTS AND METHODS: One hundred and fifty consecutive patients with a delta wave present on electrocardiogram referred for ablation had prior full diagnostic electrophysiological study. RESULTS: In 83% (124 of 150) of patients, the index accessory pathway was responsible for tachycardia and single catheter ablation would suffice. In 11% (17 of 150) of patients, the index pathway was not found to be the culprit producing tachycardia and in another 6% (nine of 150) additional information was obtained from electrophysiological study with possible clinical significance. CONCLUSIONS: Omission of the full diagnostic electrophysiological study is acceptable in the majority of patients presenting with a delta wave on electrocardiogram. However, important clinical information is missed in a sizeable minority of patients.

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↗
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

[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↗