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Biomedical subjects

M C Aumont

Publications and source records attributed to M C Aumont.

At least 19 recordsLinked to original sources
PubMed1999

Acute assessment of microvascular perfusion patterns by myocardial contrast echocardiography during myocardial infarction: relation to timing and extent of functional recovery.

OBJECTIVE: To examine the relation between the initial microvascular perfusion pattern, as assessed by intracoronary myocardial contrast echocardiography (MCE), immediately after restoration of TIMI (thrombolysis in myocardial infarction) (TIMI) grade 3 flow during acute myocardial infarction, and the extent and timing of functional recovery in the area at risk. SETTING: Referral centre for interventional cardiology. METHODS: Intracoronary MCE was performed 15 minutes after TIMI grade 3 recanalisation of the infarct artery in 25 patients. Segmental myocardial contrast patterns were graded semiquantitatively (0, none; 0.5, heterogeneous; 1, homogeneous). Functional recovery was assessed by echocardiography on days 9 and 42. RESULTS: Among 174 myocardial segments in the area at risk, wall motion recovery on day 9 was observed in 40% of MCE grade 1 segments but there was no significant recovery in grade 0 or 0.5 segments. On day 42, recovery had occurred in 56% of MCE grade 1 segments (p < 0. 0001 v MCE grade 0 and 0.5; p = 0.0001 v MCE grade 1 on day 9), and 22% of MCE grade 0.5 segments (p = 0.02 v MCE grade 0; p = 0.0005 v MCE grade 0.5 on day 9); MCE grade 0 segments did not recover. Negative predictive value in predicting recovery by contrast enhancement was 95% and 89% by days 9 and 42, respectively. CONCLUSIONS: Contractile recovery occurs earliest in well reperfused segments. Up to one quarter of segments with heterogeneous contrast enhancement show wall motion recovery within the first six weeks. Myocardial perfusion after recanalisation in acute myocardial infarction, even if heterogeneous, is a prerequisite for postischaemic functional recovery. Thus preservation of acute myocardial perfusion is associated with more complete and early functional recovery.

Adult↗
PubMed1999

Polymorphisms of the tissue factor pathway inhibitor (TFPI) gene in patients with acute coronary syndromes and in healthy subjects : impact of the V264M substitution on plasma levels of TFPI.

-Mutations of the gene encoding tissue factor pathway inhibitor (TFPI), an inhibitor of TF-induced activation of the coagulation cascade, were screened for in 130 patients and 142 healthy controls to determine whether these variants contribute to acute coronary syndromes or modify plasma TFPI levels. The following 3 new polymorphisms were identified: 384T-->C in exon IV, which does not change the corresponding amino acid (tyrosine 57); -33C-->T in intron 7 (the T/T, C/T, and C/C genotypes were found in approximately 50%, 40%, and 10% of subjects in both groups); and 874G-->A in exon IX (GTG-->ATG), which predicts a valine to methionine change (V264M) in the carboxy-terminus tail of TFPI. The V264M polymorphism was found in 9.2% of the cases and 4.9% of the controls; the associated odds ratio (OR) for acute coronary syndromes was 2.0 (95% confidence interval [CI], 0.7 to 5.1). The OR increased to 3.6 (95% CI, 0.8 to 15.7) and 3.2 (95% CI, 0.9 to 11.8) in nonsmokers and patients without other risk factors, respectively. The possible link between the V264M polymorphism and coronary heart disease was checked in a large case-control study of myocardial infarction (Etude Cas-Témoins de l'Infarctus du Myocarde [the ECTIM Study]). The results showed no link between the V264M polymorphism and coronary syndromes. Interestingly, however, 5 patients heterozygous for the V264M polymorphism had significantly lower plasma TFPI levels than did 13 patients with the most common genotype. Although our present results do not support an association between TFPI polymorphisms and acute coronary syndromes, the possibility that 1 of them, especially the exon IX polymorphism, is associated with subtypes of myocardial infarction or to evolutive particularities that were not assessed in this study, cannot be excluded and is currently being evaluated.

Acute Disease↗
PubMed1997

[Thrombocytopenia after cardiac surgery due to anti-platelet allo-immunization. Apropos of a case].

Thrombocytopaenia is rare after cardiac surgery but carries a very high risk of bleeding and thrombotic complications. It is generally due to heparinisation but may be secondary to the surgical procedure itself (cardiopulmonary bypass, sepsis, platelet consumption by the prosthesis), or associated factors (massive blood transfusion, drug reaction, rare antiplatelet allo-immunisation). One case of post-transfusion thrombocytopenia with antiplatelet anti-HPA-la allo-antibodies with a favourable outcome with high dose polyvalent gammaglobulins is reported. The authors describe the diagnostic and therapeutic approaches to this problem.

Aged↗
PubMed1997

[Evaluation of the cost of a systematic early reperfusion of the infarction artery by primary or salvage angioplasty].

In order to evaluate the cost of a strategy designed to ensure a maximal early patency rate of the coronary artery responsible for acute myocardial infarction, we retrospectively studied 112 unselected, consecutive patients, treated during the 6 hours following onset of symptoms, either by intravenous thrombolysis (group 1, n = 57) followed by coronary angiography at the 90 th minute, and if necessary rescue angioplasty, or by primary angioplasty (group 2, n = 49), or finally by simple conventional medical treatment (group 3, contraindications to thrombolysis and catheterization, n = 6). The costs of medical treatment were expressed as standard mean costs, and were compared with total hospital expenditure. The overall hospital mortality was 8.0%: 3.5% in group 1, 8.2% in group 2, and 50% in group 3. The total cost of medical procedures during the initial hospital stay was 16,684 F, identical in groups 1 and 2 (17,985 F and 16,780 F, respectively). Total hospital expenditure was 36,254 F, with no significant difference between groups 1 and 2 (34,086 F and 41,670 F, respectively), despite a tendency towards a higher cost in group 2. This tendency reflected that of a longer hospital stay for patients in group 2, due to their more severe condition, but the proportion of medical cost within the total hospital expenditure was lower than in group 1 (40% and 53%, respectively). After one year of follow-up, only one other death from a cardiac cause was reported: the supplementary expenditure amounted to 14,617 F. This maximal reperfusion strategy during the acute phase of myocardial infarction achieved a low hospital mortality and one-year mortality, without a marked excess medical cost compared to previously published estimations. Primary angioplasty appears to have allowed a certain reduction of this cost compared to thrombolysis, but the heterogeneity of the study population does not allow direct comparison of the costs of the 2 reperfusion methods. One half of the total expenditure remains directly dependent on the duration of the hospital stay.

Angioplasty, Balloon, Coronary↗
PubMed1996

[Secondary prevention after myocardial infarction; rôle of platelet antiaggregants and hypolipemic agents].

The goals of secondary prevention after myocardial infarction are to avoid the complications of infarction itself, to prevent reinfarction, to detect and treat ischaemic episodes and to slow the progression of atherosclerosis. Antiplatelet therapy, especially with aspirin, has a clearcut beneficial effect decreasing cardiovascular mortality and of non-fatal reinfarction. A metaanalysis of ten trials has shown a 25% decrease in vascular events in the long-term, irrespective of age, gender, blood pressure blood glucose level, and dosage whether low (75 to 160 mg) or moderate (160 to 325 mg/day). Apart from the irreversible inhibition of cyclooxygenase, a beneficial effect on remodelling may be observed. Lipid lowering therapy has made significant advances since the introduction of the statimes. Compared with fibrates, statines have the advantage of reducing total mortality in addition to coronary mortality, whereas the fibrates, though reducing the latter, have been reported to increase total mortality and non-coronary mortality, but in a non-significant manner. Fibrates remain the drugs of choice for the treatment of pure hypertriglyceridaemia. The mechanisms of action of the statine are diverse: effects on endothelium-dependent relaxation, haemostasis, stabilisation of the atheromatous plaque and prevention of its rupture. The cost/effectiveness ratio of aspirin and statines is very high, the latter being much more cost-effective than, for example, the treatment of mild hypertension.

Anticholesteremic Agents↗
PubMed1995

Relationship between Rap1 protein phosphorylation and regulation of Ca2+ transport in platelets: a new approach.

Although the interrelationship between the two messengers Ca2+ and cyclic AMP in platelet function is well documented, its mechanism of action still remains to be established. We investigated here the question of the regulation of platelet Ca(2+)-ATPases by cyclic AMP through the phosphorylation of the Rap1 protein using a pathological model. We first found experimental conditions where Ca(2+)-transport by platelet membrane vesicles appeared to be dependent on the phosphorylation of the Rap1 protein. Then, we studied platelets of patients with congestive heart failure for their expression of the potential 97 kDa Ca(2+)-ATPase target of regulation through the Rap1 protein as well as the phosphorylation of the Rap1 protein using the catalytic subunit of the cyclic AMP-dependent protein kinase (C. Sub.). In the first patients studied, we found no significant modification in the expression of the 97 kDa Ca(2+)-ATPase by Western blotting using the PL/IM 430 monoclonal antibody which specifically recognized this isoform. In contrast, the Rap1 protein was differentially phosphorylated when using 15 micrograms/ml of the C. Sub. These results allowed us to use these pathological platelets to study the relationship between the expression of Rap1 protein and the regulation of Ca2+ transport by selecting a patient with severe heart failure. We could show a decrease in the expression as well as in the phosphorylation of Rap1 protein and demonstrate a lower effect of C. Sub. on Ca2+ transport. Finally, by studying a further series of patients, we could confirm that the decrease in Rap1 protein expression in heart failure, whatever its extent, was variable, and could strictly correlate the expression of Rap1 protein with the stimulatory effect of C. Sub. on Ca2+ transport. Besides the evidence for regulation of the expression of the Rap1 protein in platelets from patients with heart failure, these findings constitute a new approach in favour of the regulation of platelet Ca2+ transport through the phosphorylation of the Rap1 protein.

Adenosine Triphosphate↗
PubMed1995

Iliac artery patency before and immediately after percutaneous transluminal angioplasty: assessment with time-of-flight MR angiography.

PURPOSE: To assess the efficacy of magnetic resonance (MR) angiography of iliac arteries before and immediately after percutaneous transluminal angioplasty (PTA). MATERIALS AND METHODS: In 14 patients with 22 diseased iliac artery segments (external or common), axial two-dimensional time-of-flight MR angiography was performed. Images were reconstructed with a maximum-intensity-projection (MIP) algorithm. MR angiography was performed 1-4 days after diagnostic digital angiography and 6-24 hours after PTA. Findings obtained before and immediately after PTA were compared for number and location of significant (ie, > 50%) stenoses, length and diameter of balloon to be employed, and diameter of the stenotic artery after PTA. Linear regression analysis was performed. RESULTS: Sensitivity and specificity of MR angiography for determination of significant stenoses were 95% and 97%, respectively. Before PTA, balloon dimensions depicted on MR angiograms and digital angiograms were well correlated (r = .76, P < .05). After PTA, MR angiograms and digital angiograms provided similar findings in all but one case. CONCLUSION: MR angiography helped determine if PTA is indicated and depicted iliac artery patency after PTA.

Adult↗
PubMed1995

[Baroreflexes and congestive heart failure].

Abnormal responses are found in the early stages of heart failure with increased sympathetic and decreased parasympathetic activity, causing peripheral arteriolar vasconstriction and tachycardia respectively. The cardiopulmonary baroreflex may be studied by decreasing venous return ("low body negative pressure") and by measuring vascular resistance forearm. The arterial baroreflex may be studied by changing aortic pressures (by intravenous phenylephrine or nitroglycerin). Orthostatism and the tilt test deactivate the cardiopulmonary and arterial baroreflexes simultaneously. These baroreflexes are impaired in patients with heart failure. Their activation does not cause the usual sympatho-inhibition so contributing to increased sympathetic tone. This dysfunction may result from a change at any point on the reflex pathway: the baroreceptors themselves, the afferent, central and efferent pathways. It is selective as during the cold pressor test, the vasoconstrictor response remains intact. One of the possible mechanisms of baroreflex dysfunction in heart failure is loss of sensitivities of the baroreceptors. This may be multifactorial: structural abnormalities, changes in compliance or functional abnormality. Even if the loss of sensitivity is partially related to a change in compliance, other factors play a role. It is more functional than structural abnormalities because, after cardiac transplantation, the baroreceptors regain their sensitivity within 2 to 3 weeks. Excessive Na-K dependent ATPase activation of the smooth muscle cells of the carotid sinus could lead to hyperpolarization of the cell membrane, so reducing the excitability of the receptor. Aldosterone is one of the factors which could activate the Na-K ATPase, as this hormone directly increases pump activity and favorizes the synthesis of new pumps in the vascular smooth muscle cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Autonomic Nervous System↗
PubMed1995

[Classic treatment of chronic heart insufficiency. What if new?].

The aims of treatment of chronic heart failure are to improve the symptoms and the quality of life, reduce mortality and prevent left ventricular dysfunction. Before the first symptom occurs, neurohormonal activation takes place (increased catecholamines and atrial natriuretic peptide levels). Diuretics improve symptoms and are irreplaceable for the elimination of salt and water overload. Loop diuretics are used more often than the thiazides. Their deleterious effects on electrolyte balance are well known. The fact that they activate the renin angiotensin system is a more recent acquisition; the increase in plasma renin activity is a poor prognostic factor. Diuretics potentialize the vasodilator effect of angiotensin converting enzyme inhibitors which inhibit the neurohumoral activation induced by the diuretics. This therapeutic association is very logical, effective and allows reduction in the dosage of the diuretic. To date, there are no large scale controlled studies of the effects of diuretics on mortality. Spironolactone corrects hypokalaemia and hypomagnesaemia induced by loop diuretics. Moreover, it has been shown experimentally in renovascular hypertension and in hyperaldosteronism, that this molecule can prevent myocardial fibrosis, a factor which leads to ventricular dysfunction. The RALES study will analyse the effect of associating spironolactone to diuretic and ACE inhibitor therapy on the mortality of patients in NYHA classes III-IV. The value of digitalis in heart failure patients with sinus rhythm is a classical controversy. Digitalis has a positive inotropic effect (inhibition of NaK-dependent ATPase). More recently, a favourable neurohormonal effect has been reported; digitalis decreases the activation of the sympathetic and renin-angiotensin systems.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1994

Eligibility for reperfusion therapy and outcome in elderly patients with acute myocardial infarction.

Reperfusion therapy by thrombolysis or angioplasty was considered in 260 unselected patients consecutively admitted within 6 h of the onset of Q wave myocardial infarction. Rates of reperfusion and in-hospital mortality were compared in 206 patients < 70 years and 54 patients > or = 70 years. Early reperfusion was obtained in 86.4% of the patients under 70 years and in 72.2% of those over 70 (P < 0.01). Thrombolysis was more frequently used in the younger group (66.0% vs 31.5%, P < 10(-5)), and primary angioplasty in the older (44.4% vs 29.6%, P < 0.05). Overall in-hospital mortality was higher in the older group (22.2% vs 4.4%, P < 10(-5)). After successful reperfusion, mortality was 12.8% in the patients over 70 and 3.9% in those under 70. After failed or unproven reperfusion, mortality was 46.7% in the patients over 70 and 7.1% in those under 70. Reperfusion therapy is feasible in the majority of patients over 70 years, but failure to attempt or to achieve reperfusion is associated with a poor outcome. Although not controlled, this study provides an incentive for attempting early reperfusion therapy as often as possible in the elderly with acute myocardial infarction.

Age Factors↗
PubMed1994

[Incidence and prognosis of early primary cardiogenic shock in myocardial infarction].

The aim of this retrospective study was to analyse the results of coronary reperfusion on the incidence and short and medium term prognosis of early primary cardiogenic shock in acute myocardial infarction. Of 339 consecutive patients admitted within 6 hours of the onset of acute myocardial infarction, 25 (7.4%) had cardiogenic shock from the onset. The majority of patients (18) underwent direct angioplasty with a successful result in 16 cases. Intravenous thrombolysis was instituted in 5 cases followed by emergency coronary angiography leading to "rescue" coronary angioplasty in 3 cases, which was successful in 2 cases. Two patients had no coronary revascularisation because of a double contra-indication to thrombolysis and catheterization by the femoral approach. Intra-aortic balloon pumping was used in 17 cases. Complementary emergency surgical revascularization was necessary in 5 patients (20%). In all, early reperfusion of the infarct-related artery was obtained in 80% of cases (20 patients). The hospital mortality was 72% (18 patients) due to refractory cardiac failure in nearly all cases. After an average follow-up of 17 months, 3 of the 7 survivors of the hospital period have died and of the 4 remaining patients, 2 are in the NYHA classes III or IV. Recent therapeutic advances have not influenced the incidence of cardiogenic shock but have significantly increased the proportion of very early cardiogenic shock, whereas the late cardiogenic shocks of more progressive onset, have nearly disappeared (4/339, 1.2% in this series). The prognosis of these early shocks, caused by severe myocardial damage, remains catastrophic and hardly improved by emergency coronary reperfusion by angioplasty and intraaortic balloon pumping.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

[Difficulties in the diagnosis of cardiac insufficiency in octogenarians].

The incidence of heart failure in octogenarians is high and its diagnosis not always easy. In many cases it is made by excess or by omission. Obtaining a history is often difficult. Signs may be masked, false or indicative of another disease process. Dyspnea, edema of the lower limbs and crepitations are relatively non-specific. Jugular distension, tender hepatomegaly and a diastolic gallop are much more valuable. Diagnosis of the underlying etiology also raises problems. While hypertension is commonplace and easy to identify, ischemic heart disease is common and often missed. Tight aortic stenosis must be identified since its treatment is surgical. Hypertrophic cardiomyopathy is often an echocardiographic discovery. Post-embolic chronic cor pulmonale, or secondary to chronic obstructive lung disease, must always be considered in the presence of right heart failure without hypertension or chest pain. Appropriate treatment is dependent upon accurate diagnosis.

Age Factors↗
PubMed1994

[Acute myocardial infarction in patients over 70 years of age].

Demographic changes in cardiovascular disease explain the marked increase in the number of myocardial infarctions affecting individuals aged over 70. The prognosis remains poor, with hospital mortality of the order of 30%. The reticence of physicians to use reperfusion techniques (intravenous thrombolysis and coronary angioplasty) is paradoxically considerable. Several studies have nevertheless shown that the benefit/risk ratio of such methods not only persists, but is increased in this age group, which should encourage the widening of their indications. Thorough evaluation of the best management strategy would require a randomised comparative trial, but angioplasty would probably ensure early reperfusion in a larger proportion of elderly patients than thrombolysis, because of the high incidence of contraindications to the latter as well as of cardiogenic shock in this age group.

Age Factors↗
PubMed1993

Primary coronary angioplasty for acute myocardial infarction with contraindication to thrombolysis.

Patients with acute myocardial infarction (AMI) and contraindication to thrombolysis have a high mortality and morbidity with conventional medical treatment. Among 226 consecutive patients hospitalized within 6 hours of the onset of Q-wave AMI, 45 (20%) had contraindications to thrombolysis. All were treated by emergent primary angioplasty. Mean age of the 45 patients was 60 +/- 11 years and 8 (18%) were > or = 70 years old; 17 (38%) had multivessel disease and 5 (11%) presented with cardiogenic shock. Successful angioplasty was achieved in 42 of the 45 patients (93%) 52 +/- 27 minutes after admission and 238 +/- 100 minutes after the onset of pain. Overall in-hospital mortality was 9% (4 of 45). Neither major bleeding nor stroke occurred. There was 1 case of early symptomatic reocclusion, treated with emergent repeat angioplasty without reinfarction. Predischarge angiography in 33 patients showed only 1 silent reocclusion (3%). Ejection fraction at discharge was 46 +/- 13%. Repeat catheterization at 6 months in 19 patients showed 4 restenoses (21%) and 4 reocclusions (21%) of the infarct-related artery. There were 3 late deaths (2 noncardiac), which gave survival rates of 87 and 85% at 1 and 3 years, respectively, and event-free survival rates of 71 and 69% including in-hospital deaths. There were no cases of late reinfarction. Consequently, in this series, primary coronary angioplasty proved safe and highly effective in rapidly restoring sustained infarct-vessel patency during AMI, and led to a greater improvement in early and late outcomes than that reported in the literature for medically treated subjects in this high-risk subset for which thrombolytic therapy is contraindicated.

Angioplasty, Balloon, Coronary↗
PubMed1993

Late thrombotic obstruction of an aortic bioprosthetic valve: successful treatment by oral anticoagulation.

Thrombotic obstruction of aortic bioprostheses is rare. Few cases have been reported involving the use of the Carpentier-Edwards (CE) prosthesis, the Hancock bioprosthesis, or the Medtronic Intact porcine valve. Thrombolytic therapy for mechanical valve thrombosis has been used frequently even though it is known to carry a high risk of embolism and recurrence. However, the use of this therapy was reported for the first time only recently, in a case of acute aortic thrombosis which occurred 3 1/2 months after bioprosthesis insertion. We report a case of late progressive thrombotic obstruction of a CE aortic valve 3 years after insertion. The case was successfully treated with coumadin therapy, as confirmed by serial Doppler echocardiographic examinations and a 3-year follow-up.

Aortic Valve↗