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Biomedical subjects

P Garot

Publications and source records attributed to P Garot.

16 recordsLinked to original sources
PubMed2003

Impact of microvascular integrity and local viability on left ventricular remodelling after reperfused acute myocardial infarction.

OBJECTIVE: To assess left ventricular remodelling in patients with reperfused acute myocardial infarction and to study its relation to microvascular damage. PATIENTS: 25 patients successfully treated by primary percutaneous coronary angioplasty for acute myocardial infarction. SETTING: University hospital METHODS: Indexed end diastolic (EDVi) and end systolic (ESVi) volumes were assessed on admission and repeated at days 1 and 8. Coronary flow reserve (CFR) was assessed in the infarct related artery on day 1. Myocardial blood volume was assessed on admission and at day 8 by myocardial contrast echocardiography. In patients who manifested persistent myocardial dysfunction at hospital discharge (n = 21), local inotropic reserve was assessed by dobutamine echocardiography at day 7. RESULTS: On admission, patients with and without local viability had similar EDVi and ESVi (EDVi 67 (9) and 73 (14) ml/m(2), respectively; ESVi 34 (8) and 40 (11) ml/m(2), respectively; NS). EDVi increased to 97 (22) ml/m(2) in patients without local viability (p < 0.01 v admission) but remained unchanged at 70 (11) ml/m(2) in patients with viable myocardium (NS v admission). For pooled patient data, the percentage change in EDVi correlated with CFR (r = 0.76, p < 0.0001) and myocardial blood volume in the infarct territory (r = 0.80, p < 0.0001). CONCLUSION: Left ventricular dilatation may preferably occur in patients without local viability and is correlated with early CFR and extent of myocardial blood volume in the infarct territory.

Blood Volume↗
PubMed2003

[Electromechanical mapping of myocardial ischemia in coronary occlusion in the pig].

The NOGA-Biosense catheter-based mapping technique has been well studied experimentally in infarction model. However, chronic myocardial ischemia with this new device has not been well explored. Thus, the aim of our study was to assess electromechanical changes in a pig aneroid constricor model. To achieved this aim, ten pigs were studied 21 days after the implantation of an aneroid constrictor around the circumflex artery. Coronary reserve assess by intracoronary Doppler flow wire was reduced in the ischemic lateral area (ILA) compared with the nonischemic zone (NIZ) (1.3 +/- 0.1 in the ILA vs. 2.3 +/- 0.2 in the NSZ; p < 0.01). TM echocardiography was used to evaluate myocardial regional contractility under basal condition and after stress induced by rapid atrial pacing. In stress state, the ischemic zone showed an impaired contractility compared with basal state (wall thickening, 32.7 +/- 7.4% vs. 59.7 +/- 8.6%; p < 0.05) whereas the non ischemic zone did not (53.8 +/- 7.6% vs. 60.8 +/- 10.1%; p = ns). Constrast echography showed a decrease in contrast intensity in subendocardium of the ila compared with the niz (46.2 +/- 16.6 vs. 99.2 +/- 35.6; p = 0.03) in pacing. Ventricular mapping quantified unipolar (UV). bipolar (BV) voltage potentials and endocardial local shortening (LLS) in 9 left ventricular regions. In basal state, electrical potentials were preserved in both zones (UV: 9.1 +/- 1.8 mV in the ischemic vs 11.3 +/- 3.6 mV in the non ischemic zone; p = ns; BV: 4.2 +/- 1.1 mV in the ILA vs. 3.9 +/- 1.5 mV; p = ns). In contrast, LLS was significantly lower in the ischemic compared with non ischemic zone (6.4 +/- 5.4% vs. 17.9 +/- 3.0%, p < 0.001). In conclusion, ventricular mapping with the NOGA-Biosense system can identify the ischemic myocardium. In this pig model, the association of a preserved electrical activity and an impaired mechanical activity characterizes the ischemic myocardium. These findings could be interesting in this model in regard of the new developments of the system in particular in the field of angiogenesis.

Animals↗
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↗
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↗
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

[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↗
PubMed1999

[Diagnostic value of endocoronary echography].

Intracoronary ultrasound allows in vivo examination of the various layers of the wall of arteries affected by atherosclerosis. Its use in the catheterisation laboratory has therefore allowed better understanding of the mechanism of the action of the various angioplasty procedures, allowing better guidance of the indications and better control of these techniques. It also helps to guide these procedures, thereby facilitating an optimal immediate result, which determines the long-term outcome. The characteristics of intracoronary ultrasound (high resolution, proximity of the arterial wall, echogenicity of constituents of the plaque) make it the instrument of choice to study the composition and structure of the plaque, which determine the clinical presentation and active potential, especially the risk of complications (rupture). The development of image and crude acoustic signal processing techniques have improved the performance of the analysis of these documents and raise hopes of one day being able to predict and anticipate plaque rupture.

Angioplasty↗
PubMed1998

Incidence, consequences, and risk factors of early reocclusion after primary and/or rescue percutaneous transluminal coronary angioplasty for acute myocardial infarction.

Percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction (AMI) achieves high patency rates. Conversely, it has been shown that after thrombolysis, early reocclusion of the infarct-related artery (IRA) is associated with substantial morbidity and mortality. The aim of this retrospective study was to study the incidence, prognostic implications, and clinical risk factors for in-hospital reocclusion of the IRA after successful emergency PTCA for AMI. We studied 399 consecutive patients (aged 59+/-14 years, 52% with anterior wall infarction) admitted <6 hours after AMI onset, of whom 374 (94%) were successfully treated with primary (n = 297) or rescue (n = 77) PTCA, with a stenting rate of 8%. Predischarge angiography was performed in 306 (82%). Early reocclusion of the IRA occurred in 28 patients (9%) and was silent in 6 (2%). The reocclusion rate was 10% for primary PTCA and 8% for rescue PTCA (p = NS). Twenty-two of 28 patients (6%) underwent repeat emergency coronary angiography because of early recurrent ischemia and most (n = 18) were treated with emergency PTCA. Early recurrent ischemia occurred mostly (86%) within 5 days of AMI onset. There was a higher prevalence of on-site hemorrhage (18% vs 5%, p = 0.007), blood transfusion (11% vs 2%, p = 0.01), pulmonary edema (21% vs 4%, p <0.01), and in-hospital death (21% vs 1%, p = 0.0001) in patients with predischarge reocclusion. On multivariate analysis, cardiogenic shock on admission and absence of dyslipidemia were strong and independent predictors (p = 0.01) of IRA reocclusion. In conclusion, early reocclusion after emergency PTCA occurred in 9% of the patients and was associated with substantial morbidity and mortality. This warrants attempts to decrease its incidence, e.g., with more frequent use of stents.

Adult↗
PubMed1998

[Therapeutic strategy of the management of acute heart failure].

Acute cardiac failure should be approached clinically and paraclinically as an emergency and precipitation is not always what is required. Consequently, strict clinical and paraclinical strategy leads to decisive action to improve the prognosis. The authors describe the principles of management of acute cardiac failure. The different stages which are carried out simultaneously in clinical practice are discussed: physiopathological basis, clinical and paraclinical investigations, symptomatic and aetiological treatment. The description and indications of circulatory assistance are considered. This constitutes a major therapeutic advance of the last decade and has changed the treatment of the most severe clinical forms of acute cardiac failure.

Acute Disease↗
PubMed1997

[Acute heart failure].

Acute cardiac failure is the principal complication of all forms of heart disease. The goal of therapy is to improve the quality and length of life, and to prevent progression of the syndrome. Although improvement in survival with medical therapy has been obtained at each stage of heart failure, quality of life has been more difficult to assess and regression of the disease is most apparent before severe symptomatic heart failure develops. Decisive recent progresses have been the development of cardiac transplantation and of assisted circulation techniques, and the generalisation of reperfusion therapies at the acute stage of myocardial infarction.

Acute Disease↗