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Biomedical subjects

E Aptecar

Publications and source records attributed to E Aptecar.

At least 19 recordsLinked to original sources
PubMed2002

[Femoro-popliteal emboli: treatment by manual thrombo-aspiration].

Acute arterial thrombo-embolic pathology constitutes a common pathology in the elderly population, principally in cases of cardiac arrhythmia. Out study allowed analysis of the results of percutaneous manual thrombo-aspiration as a primary procedure in a series of 25 patients (average age: 73.3 +/- 11.3 years) presenting with a picture of acute femoro-popliteal ischaemia, of supposed cardiac origin. Most of the patients had an arrhythmia with atrial fibrillation (68%), and 88% had grade II ischaemia. The site of proximal occlusion most frequently found was the popliteal axis (22 patients). Thrombo-aspiration was performed in all cases via the common femoral route homo-lateral with the ischaemia, by anterograde approach, after having obtained a diagnostic angiograph of the opposite side. The procedure, with an average duration of 39 minutes, allowed restoration of good quality flow in at least 2 axes subjacent to the occlusion in 23 patients (92%). Besides two failures, two complications (8%) were counted (one Scarpa haematoma and one early re-thrombosis). This good result was sustained long term, with 94% of patients reviewed on average 3 years after the procedure remaining asymptomatic. Manual thrombo-aspiration thus constitutes a technique of choice in the framework of the management of acute infra-inguinal emboli due to its angiographic and functional results on the one hand, and its low morbidity on the other, in a population particularly exposed to the risk of spontaneous and post-operative vascular complications.

Aged↗
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

Immunologic events and long-term survival after combined heart and kidney transplantation: a 12-year single-center experience.

BACKGROUND: In this study we compare the incidence of cardiac rejection and long-term survival after combined heart and kidney transplantation (HK) and single heart transplantation (H). Combined HK transplantation is a surgical option for patients with irreversible cardiac and renal failure. However, long-term results of combined HK transplantation on immunologic events and patient survival remain unknown. METHODS: Between 1988 and 1997, 12 consecutive patients underwent combined HK transplantation (HK group) at a single institution. A control group (H group) of 24 single heart transplant recipients operated on within the same period was matched for age, pre-operative pulmonary vascular resistance, hepatic insufficiency and gender mismatch. Recipients and donors were ABO compatible without HLA antigen matching. All patients received immediate triple immunosuppression that included cyclosporine. Because of early renal dysfunction, cyclosporine was switched to anti-thymocyte globulin in 5 patients from the HK group and in 1 patient from the H group (p = 0.01). RESULTS: Actuarial freedom from heart rejection at 6 months and at 1 year following transplantation averaged 90 +/- 9% and 70 +/- 14% in the HK group, and 65 +/- 10% and 49 +/- 11% in the H group, respectively (p = 0.023). Actuarial survival at 1, 5 and 12 years was not significantly different between groups, at 66%, 55% and 28% in the HK group, and 66%, 44% and 32% in the H group, respectively (p = 0.66). CONCLUSION: The incidence of cardiac rejection was significantly lower. Long-term survival in the HK group was similar to that in the H group. Putative mechanisms of decreased cardiac rejection in the HK group include allogeneic stimulation, donor-derived dendritic cells and induction by anti-thymocyte globulins. The need for long-term immunosuppression may be reduced after combined heart and kidney transplantation.

ABO Blood-Group System↗
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

Short-term variability of pulse pressure and systolic and diastolic time in heart transplant recipients.

In heart transplant recipients (HTR), short-term systolic blood pressure variability is preserved, whereas heart rate variability is almost abolished. Heart period is the sum of left ventricular ejection time (LVET) and diastolic time (DT). In the present time-domain prospective study, we tested the hypothesis that short-term fluctuations in aortic pulse pressure (PP) in HTR were related to fluctuations in LVET. Seventeen male HTR (age 48 +/- 6 yr) were studied 16 +/- 11 mo after transplantation. Aortic root pressure was obtained over a 15-s period using a micromanometer both at rest (n = 17) and following the cold pressor test (CPT, n = 14). There was a strong positive linear relationship between beat-to-beat LVET and beat-to-beat PP in all patients at rest and in 13 of 14 patients following CPT (each P < 0.01). The slope of this relationship showed little scatter both at rest (0.34 +/- 0.07 mmHg/ms) and following CPT (0.35 +/- 0.09 mmHg/ms, P = not significant). Given the essentially fixed heart period, DT varied inversely with LVET. As a result, in 13 of 17 HTR at rest and in 12 of 14 HTR following CPT, there was a negative linear relationship between beat-to-beat PP and DT. In conclusion, our short-term time-domain study demonstrated a strong positive linear relationship between LVET and blood pressure variability in male HTR. We also identified a subgroup of HTR in whom there was a mismatch between PP and DT.

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

[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↗
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

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↗
PubMed1997

Ventriculoarterial coupling and left ventricular efficiency in heart transplant recipients.

BACKGROUND: In heart transplants, left ventricular function may be impaired in the absence of rejection or graft atherosclerosis. Matching between left ventricle and arterial receptor, i.e., ventriculoarterial coupling, and left ventricular efficiency have never been studied. METHODS: Left ventricular pressure-volume loops and single beat analysis were used to determine effective arterial elastance (Ea) and the slope of the end-systolic pressure-volume relation (end-systolic elastance; Ees). Left ventricular efficiency was evaluated by determination of external work (EW), pressure-volume area (PVA), coronary blood flow (continuous thermodilution), and myocardial oxygen consumption (MVO2). Measurements were made at baseline in 11 control subjects and 9 heart transplant recipients (HTX) without rejection and were repeated after phenylephrine in the latter group. RESULTS: At baseline, Ees, Ees/Ea, and work efficiency (EW/PVA) were lower in HTX than in control subjects (2.51+/-0.87 vs. 3.70+/-1.15 mmHg/ml/m2, P<0.01; 0.96+/-0.21 vs. 1.47+/-0.31, P<0.001; and 0.53+/-0.08 vs. 0.59+/-0.09, P<0.01, respectively). Energy conversion efficiency (PVA/MVO2) and mechanical efficiency (EW/ MVO2) were higher in HTX (0.58+/-0.08 vs. 0.45+/-0.14, P<0.001; and 0.31+/-0.05 vs. 0.26+/-0.06, P<0.001, respectively). In HTX, phenylephrine infusion increased Ees, Ea, EW, PVA, and MVO2 without modifying Ees/Ea, EW/PVA, PVA/MVO2, and EW/MVO2. CONCLUSIONS: In heart transplants, (1) left ventricular contractility is moderately depressed; (2) elevation of energy conversion efficiency compensates for the decrease in work efficiency, allowing normal mechanical efficiency; and (3) alpha 1 adrenergic stimulation does not impair ventriculoarterial coupling and mechanical efficiency.

Adult↗