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P Dupouy

Publications and source records attributed to P Dupouy.

At least 19 recordsLinked to original sources
PubMed2001

Impact of coronary plaque morphology as assessed by IVUS computer-aided analysis on mechanisms of balloon angioplasty and stenting.

This study was performed in order to quantitate structural coronary plaque modifications after balloon angioplasty and stenting and to evaluate the impact of plaque morphology on the mechanisms of lumen enlargement during angioplasty. Plaque morphology was studied by computer-aided analysis of 60 cross-sectional intravascular ultrasound (IVUS) images of the target lesion in 20 patients undergoing percutaneous coronary angioplasty. Based on a computer-aided video densitometry classification of plaque morphology, three groups of plaques were defined based on the slope value of a fifth polynomial regression of the plaque gray-level distribution. In groups A and B, balloon angioplasty provided significant increases in lumen area (P < 0.0001) and vessel area (P < 0.05) without a reduction in plaque area; neither parameter increased in group C. In group A, stenting was associated with an additional lumen enlargement (P < 0.0001) due to plaque reduction (P < 0.05). In groups B and C, stenting further increased lumen area (P < 0.0001) by improving vessel area (P < 0.001) but without plaque reduction. Balloon angioplasty and stenting provided a significant decrease in plaque area in group A as compared to groups B (P < 0.05) and C (P < 0.01). Finally, vessel area improvement was greater in group B than in groups A (P < 0.01) and C (P < 0.05). The mechanisms underlying lumen enlargement after coronary angioplasty are highly dependent on plaque morphology as defined by an IVUS computer-aided analysis and may differ between balloon angioplasty and stenting.

Angioplasty, Balloon, Coronary↗
PubMed2001

Numerical and experimental models of post-operative realistic flows in stenosed coronary bypasses.

By means of both experimental and finite element methods, we simulated three-dimensional unsteady flows through coronary bypass anastomosis. The host artery includes a stenosis shape located at two different distances of grafting. The inflow rates are issued from in vivo measurements in patients who had undergone coronary bypass surgery a few days before. We provide a comparison between experimental and numerical velocity profiles coupled with the numerical analysis of spatial and temporal wall shear stress evolution. The interaction between the graft and coronary flows has been demonstrated. The phase inflow difference can partly be responsible for specific flow phenomena: jet deflection towards a preferential wall or feedback phenomenon that causes the flapping of the post-stenotic jet during the cardiac cycle. In conclusion, we showed the sensitivity of these typical flows to distance of grafting, inflows waveforms but also to their phase difference.

Blood Flow Velocity↗
PubMed2001

Randomised comparison of coronary stenting with and without balloon predilatation in selected patients.

BACKGROUND: The SWIBAP (stent without balloon predilatation) prospective randomised trial was designed to compare direct coronary stenting with stenting preceded by lesion predilatation with an angioplasty balloon. OBJECTIVE: To determine the feasibility and safety of direct stenting in non-complex coronary lesions in a prospective study. PATIENTS AND DESIGN: All patients < 76 years of age scheduled to undergo angioplasty of a non-complex, non-calcified lesion in a coronary artery of > 3.0 mm, who granted their informed consent, were randomised into the trial. In group I, the stent was placed without balloon predilatation, while in group II stent implantation was preceded by balloon predilatation. The primary end point was the angiographic result according to procedure assigned by randomisation. An intravascular ultrasound substudy was performed in 60 patients. RESULTS: Stent implantation was successful without predilatation in 192 of the 197 group I patients (97.5%), and with predilatation in 197 of the 199 group II patients (99%) (NS). No in-hospital stent thrombosis or death occurred. Overall procedural times, fluoroscopy times, and volumes of contrast agent given (mean (SD)) in group I v group II were 23.50 (13.54) min v 27.96 (15.23) min (p = 0.002), 6.04 (4.13) min v 6.67 (3.65) min (NS), and 135 (65) ml v 157 (62) ml (p < 0.001), respectively. No major adverse cardiovascular events had occurred by 30 days. CONCLUSIONS: The feasibility and safety of direct stenting of selected and non-complex coronary lesions is confirmed. This technique was as successful as the conventional approach and was associated with a minor reduction in fluoroscopic exposure and procedure time and the administration of less contrast agent.

Angioplasty, Balloon, Coronary↗
PubMed2000

Physiologically guided angioplasty in support to a provisional stenting strategy: immediate and six-month outcome.

The results of an observational multicenter angioplasty study suggested that stenting decisions may be facilitated by physiologic data. The purpose of this study was to evaluate the early and long-term clinical and angiographic outcome of prospective physiologically guided provisional stenting. Coronary angioplasty using a Doppler-tipped angioplasty guidewire was performed in 68 patients. The provisional stent strategy dictated that balloon angioplasty was to be continued until a coronary flow reserve was >/= 2.2 with a residual diameter stenosis by quantitative coronary angiography < 35%. Repeat coronary angiography was obtained at 6 months. Based on the study criteria, 32/68 patients (47%) received a stent. Compared to the stent group, the angioplasty alone group had higher postprocedural stenosis (23% +/- 13% vs. 13% +/- 10%; P < 0. 05) and lower coronary vasodilatory reserve (2.3 +/- 0.4 vs. 2.6 +/- 0.7; P < 0.05). At follow-up (6.0 +/- 1.5 months), the angiographic restenosis rate was 39% in the angioplasty group and 35% in the stent groups (P = NS). Adverse cardiac events (unstable angina, target lesion revascularization, myocardial infarction, death) occurred in 19% and 18% (P = NS) of the angioplasty and stent patients, respectively. A prospective application of a physiologically guided provisional stent strategy for coronary angioplasty indicated that stent implantation may be required in approximately 50% of patients, an approach that produces similar clinical and angiographic long-term outcomes for stenting and guided angioplasty. These data support a role of coronary physiology as an adjunct in conducting an angioplasty procedure without obligatory stenting.

Adult↗
PubMed2000

Effects of bradykinin on coronary blood flow and vasomotion in transplant patients.

OBJECTIVES: To evaluate the effects of exogenous bradykinin on coronary epicardial and microcirculatory tone in transplant patients (HTXs), and to compare them with the effects of acetylcholine. BACKGROUND: Coronary endothelial dysfunction has been reported to occur early after heart transplantation, most notably when acetylcholine was the endothelium-function marker used. The effects of bradykinin on coronary vasomotion are unknown in HTXs. METHODS: Sixteen HTXs were compared 3.6 +/- 1.7 months after transplantation to seven control subjects. Coronary flow velocity was measured using guide-wire Doppler. Diameters (D) of three segments of the left coronary artery and coronary blood flow (CBF) were assessed at baseline, after 3-min infusions of increasing bradykinin doses (50, 150 and 250 ng/min) then of increasing acetylcholine doses (estimated blood concentrations of 10(-8), 10(-7) and 10(-6) M). RESULTS: Bradykinin induced similar dose-dependent increases in D and CBF in both groups: D was 11 +/- 12%, 19 +/- 14% and 22 +/- 16% (all p < 0.0001), and CBF was 50 +/- 40%, 130 +/- 68% and 186 +/- 77% (all p < 0.0001). Acetylcholine induced significant epicardial vasodilation in control subjects and vasoconstriction in HTX, as well as a marked increase in CBF in both groups. Acute allograft rejection, present in 8 of the 16 HTXs, did not modify responses to bradykinin, but was associated with a smaller CBF increase in response to acetylcholine (p < 0.05). CONCLUSIONS: The coronary vasodilating effects of bradykinin are preserved early after heart transplantation, even in the presence of acute allograft rejection. Although there is an abnormal vasoconstricting response to acetylcholine reflecting endothelium dysfunction, the endothelium remains a functionally active organ in heart transplant recipients.

Acetylcholine↗
PubMed2000

The French Randomized Optimal Stenting Trial: a prospective evaluation of provisional stenting guided by coronary velocity reserve and quantitative coronary angiography. F.R.O.S.T. Study Group.

OBJECTIVES: We sought to make a prospective comparison of systematic stenting with provisional stenting guided by Doppler measurements of coronary velocity reserve and quantitative coronary angiography. BACKGROUND: Despite the increasing use of stents during percutaneous transluminal coronary angioplasty, it is unclear whether systematic stenting is superior to a strategy of provisional stenting in which stents are placed only in patients with unsatisfactory results or as a bail-out procedure. METHODS: Two hundred fifty-one patients undergoing elective coronary angioplasty were randomly assigned either to provisional stenting (group 1, in which stenting was performed if postangioplasty coronary velocity reserve was <2.2 and/or residual stenosis > or =35% or as bail-out) or to systematic stenting (group 2). The primary end point was the six-month angiographic minimal lumen diameter (MLD). Major adverse cardiac events were secondary end points (death, acute myocardial infarction and target lesion revascularization). RESULTS: Stenting was performed in 48.4% of patients in group 1 and 100% of patients in group 2 (p<0.01). Six months after angioplasty, the MLD did not differ between groups (1.90+/-0.79 mm vs. 1.99+/-0.70 mm, p = 0.39), as was the rate of binary restenosis (27.1% vs. 21.4%, p = 0.37). Among patients with restenosis, 13/32 (40.6%) in group 1 but 100% (25/25) in group 2 had in-stent restenosis (p<0.01). Target lesion revascularization (15.1% vs. 14.4% in groups 1 and 2 respectively, p = 0.89) and major adverse cardiac events (15.1% vs. 16.0%, p = 0.85) were not significantly different. CONCLUSIONS: Systematic stenting does not provide superior angiographic results at six months as compared with provisional stenting.

Aged↗
PubMed1999

Prediction of functional recovery of viable myocardium after delayed revascularization in postinfarction patients: accuracy of dobutamine stress echocardiography and influence of long-term vessel patency.

OBJECTIVES: We sought to evaluate dobutamine stress echocardiography (DSE) for predicting recovery of viable myocardium after revascularization with cineangiography as a gold standard for left ventricular (LV) function. We studied the influence of late vessel reocclusion on regional LV function. BACKGROUND: Dobutamine stress echocardiography is a well established evaluation method for myocardial viability assessment. In previous studies the reference method for assessing LV recovery was echocardiography, long-term vessel patency has not been systematically addressed. METHODS: Sixty-eight patients with a first acute myocardial infarction (AMI) and residual stenosis of the infarct related artery (IRA) underwent DSE (mean +/- standard deviation) 21 +/- 12 days after AMI to evaluate myocardial viability. Revascularization of the IRA was performed in 54 patients by angioplasty (n = 43) or bypass grafting (n = 11). Coronary angiography and LV cineangiography were repeated at four months to assess LV function and IRA patency. RESULTS: Sensitivity and specificity of DSE for predicting myocardial recovery after revascularization were 83% and 82%. In the case of late IRA patency, specificity increased to 95%, whereas sensitivity remained unchanged. In the 16 patients with myocardial viability and late IRA patency, echocardiographic wall motion score index decreased after revascularization from 1.83 +/- 0.15 to 1.36 +/- 0.17 (p = 0.0001), and left ventricular ejection fraction (LVEF) increased from 0.52 +/- 0.06 to 0.57 +/- 0.06 (p = 0.0004), whereas in five patients, reocclusion of the IRA prevented improvement of segmental or global LV function despite initially viable myocardium. CONCLUSIONS: Dobutamine stress echocardiography is reliable to predict recovery of viable myocardium after revascularization in postinfarction patients. Late reocclusion of the IRA may prevent LV recovery and influence the accuracy of DSE.

Adult↗
PubMed1999

Coronary blood flow reserve and wall motion recovery in patients undergoing angioplasty for myocardial infarction.

AIMS: The aim of this study was to evaluate the relationship between coronary flow reserve and the recovery of wall motion contractility in patients with recent myocardial infarction. METHODS AND RESULTS: Nineteen patients (55 +/- 8 years) undergoing balloon angioplasty for recent myocardial infarction were studied. After angioplasty, coronary flow reserve was lower in the infarct-related artery than in a reference artery, 2.2 +/- 0.6 and 2.8 +/- 0.7, respectively, P < 0.05. There was no immediate correlation between coronary blood flow reserve measured after angioplasty and wall motion index. There was a negative correlation between coronary flow reserve and the number of necrotic segments (r = -0.43; P0.006). At the 4 month control angiogram, there was a significant increase in both left ventricular ejection fraction (59 +/- 14% vs 51 +/- 13%; P < 0.05) and wall motion index (-0.63 +/- 1.2 vs -1.94 +/- 0.9 units SD, P = 0.005). In patients in whom wall motion improved (> 1 unit SD), the immediate coronary flow reserve was higher (P < 0.05) than in patients without improved wall motion. In this group, the increase in wall motion index was correlated to the coronary blood flow reserve (r = 0.55; P < 0.02). CONCLUSION: These data show that after myocardial infarction, coronary flow reserve is associated with myocardial viability.

Aged↗
PubMed1999

Local gene delivery within the media of rabbit iliac arteries by using the infiltrator intramural delivery device.

Percutaneous transluminal angioplasty continues to be limited by restenosis. Prevention of restenosis is now focusing on local delivery of therapeutic agents, such as proliferation-inhibiting genes, directly to the site of arterial injury. We evaluated use of the Infiltrator catheter (IVT, San Diego, CA. U.S.A.) for gene delivery within the arterial media. The goals of our study were to evaluate the histologic effects of the injection and the suitability of the Infiltrator catheter for local delivery of viral therapy. We injected the femoral arteries of 21 New Zealand White rabbits. Six animals were used for an evaluation of the intramural distribution of dextran/rhodamine injected via the Infiltrator catheter. In seven animals, injection site histology and in vitro vasoreactivity were studied after an injection of saline. In the remaining eight animals, a replication-deficient adenovirus encoding for the firefly luciferase gene (Ad RSVLuc) was injected, and luciferase activity was quantified 3 and 8 days later. After injection via the Infiltrator catheter, the fluorescent tracer was distributed throughout the entire circumference and width of the arteries. Histologic examination showed minimal damage with partial endothelial abrasion and disruption of the internal elastic lamina confined to the penetration sites. In vitro endothelium-dependent vasodilation was present at a reduced level after injection via the Infiltrator (maximal endothelium-dependent acetylcholine-induced relaxation, 51.5 +/- 7.4% vs. 23.8 +/- 14.6%; p < 0.05). Significant luciferase expression was found in all the arteries, with a significant increase from day 3 to day 8 (5,392.5 +/- 2,300 vs. 2,012 +/- 471 cpm/mg; p < 0.05). These data obtained in a rabbit iliac artery model show that the Infiltrator catheter is an efficient and safe local intramural delivery device that provides significant transgene expression in the arterial wall without causing significant structural damage.

Adenoviridae↗
PubMed1999

[Ultrasonic imaging of coronary atherosclerosis].

Intra-coronary ultrasonography (ICV) is a technique for in vivo study of the different layers of the arterial wall, the site of atherosclerosis. A qualitative analysis of the composition of the plaque can predict its potential evolutivity (chronic with slow progression or at risk of rupture and causing acute thrombosis) and its response to different types of angioplasty, which could eventually become and essential factor in the choice of appropriate therapeutic strategy. Analysis of the results of B mode ultrasonic scanning has provided correlations with the histological composition of the arterial wall, validating the method and opening up the field of tissue characterisation which hitherto had been limited by the absence of sufficiently reliable, accurate and reproducible quantitative parameters. Magnetic resonance imaging (MRI) is a complementary, non-invasive tool for tissue analysis because its sensitivity to the biophysical and biochemical properties of tissues which makes it a promising method of morphological and functional imaging. Other methods of imaging atheromatous plaques include angioscopy and optic coherence tomography which have also contributed to the improvement in our knowledge of atherosclerosis. These methods of imaging which are slowly overcoming their limitations provide documents which ressemble more and more the histological appearances. Intracoronary ultrasonography is the most promising method and raises hopes that one day we shall be able to predict the outcome and anticipate the risk of rupture of atherosclerotic plaques.

Coronary Artery Disease↗
PubMed1999

[Intra-coronary ultrasonography during angioplastic procedures].

Thanks to miniaturization and constant improvement of technologies, intracoronary ultrasound (ICUS) progressively takes its place as the best tool to accurately analyze arterial wall structure. However, its routine use during interventional procedures remains limited. ICUS provides precious informations, complementary to angiography, and guide interventional procedures on the basis of a more accurate analyze of the components of the plaque, thus improving their success rate. Since its use favorized the understanding of the different devices mechanisms (angioplasty, stents, directional and rotational atherectomy), ICUS contributed to reduce the incidence of their complications. Many studies have emphasized ICUS interest during these procedures: their results seem to be significantly improved by the way of prompting the operator to adopt an aggressive strategy (additional inflations using high pressures, combination of different techniques...) which tend to reduce the complication rate and the restenosis incidence. Actually, the restenosis rate was in all these studies [OARS (29%), ABACAS (21%) and MUSIC (8.3%)] directly associated to ICUS parameters measured immediately after treatment, particularly the residual plaque burden. Whether its use, that engender substantial cost, cannot be systematic, trained centers will probably demonstrate that a rational and suitable use lead to adopt optimal strategies and achieve improved results.

Angioplasty, Balloon, Coronary↗
PubMed1999

[Coronary microcirculation. Physiologic and pathologic aspects].

The coronary circulation has a protective regulation system which, in extreme haemodynamic conditions, compensates increased myocardial oxygen demand. The coronary reserve, based on this concept defines the capacity of the system to increase flow temporally, and, thereby, myocardial oxygen supply. The introduction of new methods of investigating the coronary microcirculation has enabled the study of this phenomenon in several cardiovascular pathologies. Two types of investigation are used currently for studying the coronary microcirculation: 1) invasive methods, especially the recently developed intracoronary Doppler and pressure guide, 2) non-invasive methods, and, in particular, contrast echocardiography, position emission tomography and magnetic nuclear resonance. These investigations allow measurement of the coronary reserve or the assessment of the myocardial consequences of abnormalities of the microcirculation. Some workers use these methods to investigate pathological coronary microcirculation in different cardiomyopathies, in the presence of different cardiovascular risk factors (hypertension, diabetes, smoking, hypercholesterolaemia) and after cardiac transplantation.

Coronary Circulation↗
PubMed1999

Coronary microcirculation and cardiovascular pathology.

The recent arrival of new techniques for exploring the coronary microcirculation has facilitated assessment of both the incidence and consequences of disorders of this network in a large number of cardiovascular diseases. The microcirculation is affected in numerous cardiomyopathies in the presence of different cardiovascular risk factors and also following cardiac transplantation. Dysfunction of the microcirculation may correspond to a reduction in the surface of the maximum section of coronary arterioles, which involves multiple mechanisms, although this phenomenon does not appear to play a role in ischaemic heart disease. Reduced coronary flow is most frequently related to vascular rarefaction of multifactorial origin, including greater or lesser degrees of intimal proliferation, perivascular fibrosis, hypertrophy of the media and extrinsic compression.

Cardiovascular Diseases↗
PubMed1999

Coronary microcirculation and cardiovascular pathology.

The recent arrival of new techniques for exploring the coronary microcirculation has facilitated assessment of both the incidence and consequences of disorders of this network in a large number of cardiovascular diseases. The microcirculation is affected in numerous cardiomyopathies in the presence of different cardiovascular risk factors and also following cardiac transplantation. Dysfunction of the microcirculation may correspond to a reduction in the surface of the maximum section of coronary arterioles, which involves multiple mechanisms, although this phenomenon does not appear to play a role in ischaemic heart disease. Reduced coronary flow is most frequently related to vascular rarefaction of multifactorial origin, including greater or lesser degrees of intimal proliferation, perivascular fibrosis, hypertrophy of the media and extrinsic compression.

Cardiovascular Diseases↗
PubMed1999

[Percutaneous suture of femoral artery after diagnostic coronary angiography].

UNLABELLED: Complete local haemostasis after femoral artery catheterization can be performed using percutaneous suture devices. To evaluate efficacy and safety of these systems after diagnostic coronary angiography, we performed a randomized study where patients were treated either with a manual compression (group C) or a percutaneous suture (group T). Fifty patients were included in each group. Patients in group C had to rest at bed during 24 hours while patients in group T had to stand up and walk immediately after complete haemostasis was obtained. All angiographies were performed using a 6 F sheath. All patients had a clinical evaluation and an echography 24 hours after the procedure and all were reached by phone call at 15 days. Both groups were similar in term of age, sex ratio, diabetes, height and weight. Complete haemostasis was obtained in 20 +/- 6 mn in group C and in 6 +/- 10 mn in group T (p < 0.001). Device technical success rate in group T was 90%; 70% of patients walked immediately down the X ray table and 90% before the 4 hours. Ambulation delay was 24 +/- 5 hours in group C and 5 +/- 9 hours in group T (p < 0.0001). Clinical and echographic complications rate were similar in both groups (8%). There was no post procedure complication in group T (especially after ambulation) nor at the phone call. CONCLUSION: Femoral artery percutaneous suture after diagnostic coronary angiography is as safe and working than manual compression. It allows an immediate mobilization and ambulation, far earlier than compression.

Aged↗
PubMed1999

[Physiology of coronary circulation and angioplasty: utopia or clinical reality?].

Small pressure transducer and Doppler quartz placed at the tip of angioplasty guide wire give the opportunity to measure coronary flow physiology parameters, the physiopathologic impact of an epicardic coronary stenosis and the efficacy of its treatment. This gives the opportunity to over ride the coronary imaging limitations. Doppler and pressure investigate a different and complementary aspect of the pressure-flow relation and may be used together in some special cases. Myocardial fractional flow reserve (FFRmyo) and relative coronary reserve concepts allow to evaluate patients with heterogeneous coronary reserve. Clinical application field is very broad and can be applied to each step of coronary angioplasty from the evaluation of intermediate lesions and the indication of angioplasty to the guidance of the procedure to the evaluation of the result, through the stenting indication and the stent placement optimization. Numerous studies has emphasized the role of physiologic coronary assessment in the cathlab. The time and economic gain of such an attitude has to be confirmed by future trials but it is clear now that it is not possible to continue to take decision on the sol visual aspect of a lesion.

Angioplasty, Balloon, Coronary↗
PubMed1998

Effects of the 14F hemopump on coronary hemodynamics in patients undergoing high-risk coronary angioplasty.

BACKGROUND: The influence of the 14F Hemopump on coronary hemodynamics in patients with coronary artery disease remains unknown. METHODS: Systemic and coronary hemodynamic measurements were obtained in eight patients among 13 who underwent high-risk coronary angioplasty in our institution with the support of the Hemopump. Coronary blood flow velocity was measured with a 0.014-inch Doppler-tipped guide wire both proximal and distal to the target lesion. RESULTS: Angioplasty decreases the diameter coronary stenosis from 76% +/- 21% to 22% +/- 11%. Hemopump support did not change systemic hemodynamics either before or after angioplasty. During angioplasty Hemopump support decreased the pulmonary capillary wedge pressure from 23.5 +/- 8.5 mm Hg to 18.6 +/- 7 mm Hg (p = 0.013). No changes in either heart rate, mean and systolic aortic pressures, and cardiac index were observed throughout the procedure. After successful angioplasty was performed, the ratio of proximal to distal flow velocity decreased from 2.11 +/- 1 to 1.65 +/- 0.2 (p = 0.05). However, Hemopump did not affect absolute coronary blood flow velocities or the phasic pattern of flow velocities (diastolic systolic velocity ratio, diastolic and systolic velocity integrals) either in proximal or distal locations either before or after angioplasty. CONCLUSIONS: This study shows that although the 14F Hemopump produces unloading of the left ventricle, it does not importantly alter coronary hemodynamics when systemic hemodynamics are stable. Whether the Hemopump would maintain or improve coronary blood flow in compromised patients remains to be determined.

Aged↗