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Biomedical subjects

R Gourgon

Publications and source records attributed to R Gourgon.

At least 19 recordsLinked to original sources
PubMed1992

Patterns of myoglobin and MM creatine kinase isoforms release early after intravenous thrombolysis or direct percutaneous transluminal coronary angioplasty for acute myocardial infarction, and implications for the early noninvasive diagnosis of reperfusion.

Early noninvasive detection of reperfusion after thrombolysis for acute myocardial infarction may enable detection of unsuccessful thrombolysis in time for rescue percutaneous transluminal coronary angioplasty (PTCA). It has been suggested that repeated measurement of myoglobin or of MM creatine kinase (CK) isoforms enables early detection of reperfusion. Twenty consecutive patients with acute myocardial infarction treated by intravenous thrombolysis underwent serial determination of myoglobin, MM3 and MM1 CK isoforms every 30 minutes after the beginning of thrombolysis. At 90 minutes, coronary angiography was performed, enabling classification of patients as with (group A) and without (group B) reperfusion. A third group of 7 patients (group C) underwent direct PTCA without antecedent thrombolysis. In all groups, there were increases in myoglobin, percentage of MM3 isoform, and ratio of MM3/MM1. These increases appeared on the average steeper and faster in group B, but the large dispersion of values in this group resulted in a wide overlap with group A. Retrospective analysis suggests that an increase in the MM3/MM1 ratio > 0.35 after 60 minutes is very specific for reperfusion (sensitivity 60% and specificity 100%). In group C, PTCA always led to a sharp increase in all biochemical parameters measured within 30 minutes. Thus, macromolecular markers can be used for very early, noninvasive detection of reperfusion with a high specificity. This could help reduce the need for emergency angiography to select candidates for rescue PTCA. Furthermore, the patterns of biochemical markers of reperfusion differ when reperfusion is initiated by either thrombolysis or PTCA.

Adult↗
PubMed1992

[Ischemic cardiomyopathy: remodeling, hypertrophy, subendocardial risk. Can processes be controlled?].

Ischaemic cardiomyopathy reflects the myocardial dysfunction caused by coronary disease. It results from the association of 1. segmental infarction(s) responsible for ventricular "remodelling", i.e. expansion of the necrotic area(s) and hypertrophy-dilatation of the rest of the ventricle, eventually concurring to heart failure; 2. areas which are viable but with a function that is reversibly compromised by severe acute or chronic ischaemia (myocardial sideration or hibernation) affecting mainly the subendocardium. The spontaneous course of cardiomyopathy towards the worst can be arrested by 1. revascularisation of the myocardium at risk by coronary reperfusion performed either as an emergency in case of infarct in the process of formation, or after detection of the viable myocardial areas by isotopic methods; 2. prevention or limitation of ventricular remodelling by coronary reperfusion and improvement of the ventricular load by administration of angiotensin-converting enzyme inhibitors and nitroglycerin. The Survival and Ventricular Enlargement study (SAVE) has been the first to demonstrate the relationship between limitation of ventricular remodelling and improvement of the secondary prognosis of infarction obtained by angiotensin-converting enzyme inhibitors.

Animals↗
PubMed1992

[Functional coupling of the left ventriculo-arterial system and aging in man].

In a haemodynamic and angiographic study at rest conducted in 25 men aged from 22 to 68 years who had no more than another risk factor for arterial disease and showed no evidence of cardiac or arterial disease several parameters were measured or calculated. Firstly, a global index of arterial system function (Ea) and its various factors: Ea = ESP/SV [ESP: left ventricular end-systolic pressure; SV: systolic volume]; Ea = (HR x TSR)+Ea' [HR: heart rate/min; TSR: total systemic resistance] where Ea' = (ESP - AoP/SV) [AoP: mean aortic pressure]. Secondly, the parameters concerning the left ventricle were the mass (m) and the m/EDV ratio [EDV: end-diastolic volume] and indices of the left ventricular systolic and diastolic functions, such as ELV = ESP/ESV [ESV: end-systolic volume], kp: the volumic distensibility module of the left ventricular chamber; relations EF - o ES [EF: ejection fraction; o ES: end-systolic constraint], and kp - m/EDV as indice of left ventricular muscle distensibility. In parallel with the subjects' age, Ea increased by joint augmentation of TSR and Ea' while m, m/EDV, ELV and kp also significantly increased. The inotropic quality of the left ventricular muscle and its intrinsic distensibility were found to be decreased in a few subjects aged over 45. Ea/ELV (reverse of ejection fraction -1) tended to increase (ELV relatively less than Ea), but this increase was not significant (P = 0.10). These results show that in the ageing man the improvement observed in the ejection fraction of the left ventricular pump corresponds roughly to the degradation of the arterial system transfer function, and the arterial system-left ventricle coupling, evaluated by the Ea/ELV ratio, is maintained (better in fact than in arterial hypertension and heart failure). This improvement is achieved by increases of m and, chiefly, m/EDV which compensate for both the increase of Ea and the relative decline of left ventricular muscle contractile quality. There is a disorder of the left ventricular pump diastolic function which is due to geometric changes in the chamber and to changes in the intrinsic distensibility of the left ventricular muscle.

Adult↗
PubMed1992

A patency-oriented strategy for early management of acute myocardial infarction using emergency coronary angiography and selective coronary angioplasty.

From June 1988 to March 1991, an unselected cohort of 150 consecutive patients with acute myocardial infarction (AMI) (less than 6 hours) was managed according to a strategy designed to ensure early patency of the infarct-related artery in the maximum number of patients. The following procedures were used: (1) intravenous thrombolysis, which was the usual treatment (n = 103), followed in 98 cases by emergency coronary angiography 90 minutes after the beginning of thrombolysis. This identified 31 thrombolysis failures (32%) and led to 19 rescue angioplasties (18 successes). All patients were then scheduled for predischarge angiography. (2) Direct angioplasty, which was performed in 40 patients because of contraindications to thrombolysis (n = 23), cardiogenic shock (n = 3), diagnostic doubt (n = 7) or "ideal" conditions for direct angioplasty (n = 7). Success (defined as Thrombolysis in Myocardial Infarction [TIMI] flow greater than 1, with a residual stenosis less than 50% in the infarct-related artery) was achieved in 36 of 40 patients (90%). (3) The 7 remaining patients were given conventional medical treatment because of advanced age, contraindications to thrombolysis and angioplasty, or spontaneous reperfusion (confirmed by emergency angiography). In all, emergency angioplasty was performed in the acute phase in 39% of the 150 patients in this nonselected cohort.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Feasibility, indications and immediate results of direct angioplasty without thrombolysis during the acute period of myocardial infarction].

Between June 1988 and November 1991, 64 out of 200 consecutive admissions (32%) before the 6th hour of myocardial infarction underwent angioplasty of first intention. Fifty men and 14 women (average age 62 +/- 11 years) benefitted from this 24 hour emergency interventional cardiology service. The indication was formal in 22% of patients because of a contra-indication to thrombolysis (N = 40) or cardiogenic shock (N = 4); in 6%, the choice was logical because of diagnostic uncertainty (N = 12); it was a deliberate choice in 4% of cases (N = 8). Successful angioplasty was defined as reperfusion of the occluded artery without circulatory delay or > 50% residual stenosis. Arterial recanalisation was attempted in all patients (associated with intraaortic balloon pumping in 3 cases) and was successful in 59 patients (92%) within 231 +/- 100 minutes of the onset of chest pain and within 49 +/- 29 minutes of hospital admission. The outcome was uncomplicated without any other intervention in 81% of patients (48/59). Three reocclusions were observed, two of which were symptomatic and treated successfully by repeat emergency angioplasty. Six surgical revascularisations were necessary (2 emergency, 4 secondary). One major complication related to the angioplasty was observed (haemopericardium). Global hospital mortality was 9% (6/64): three of the 4 patients admitted in cardiogenic shock, 3 of the 40 high risk patients with contra-indications to thrombolytic therapy, none of the 20 patients considered to be at low risk (uncertain diagnosis and deliberate choice).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

[Acute hemodynamic effects of SIN-1 and isosorbide dinitrate in stable left ventricular failure: a comparative double-blind, cross-over study].

The acute hemodynamic effects of intravenous SIN-1 (1 mg) and sublingual isosorbide dinitrate (5 mg) were investigated in 12 patients (8 men and 4 women) between 38 and 80 years of age and suffering from stable chronic left ventricular failure (NYHA Classes III-IV) secondary to ischemic myocardiopathy (n = 5), hypertensive disease (n = 2) or idiopathic disorder (n = 5) corresponding to the following hemodynamic inclusion criteria: stable condition, cardiac index > or = 2 l/min/m2, mean capillary pressure > or = 18 mmHg and < or = 28 mmHg. Previous treatments were continued with the exception of vasodilators and diuretics which were stopped 24 hours earlier. The hemodynamic data from this cross-over, double-blind double-dummy trial were collected for two 60-hour periods separated by a washout period of 120 minutes. Simultaneously, venous samples were taken for the assay of plasma levels of SIN-1. The heart rate, cardiac output, pulmonary artery resistance and blood pressure were not affected by either SIN-1 or isosorbide dinitrate. An obvious reduction (> 15% of the basal value) in the mean capillary pressure, pulmonary artery pressure and mean right atrial pressure was observed in 10 subjects after SIN-1 and in 7 patients isosorbide dinitrate. A statistically non-significant trend towards a more marked effect (number of patients responding and maximum amplitude of pressure reduction) which occurred more rapidly and lasted longer was observed after SIN-1. Analysis of the relationship between the pharmacodynamics and pharmacokinetics of SIN-1 suggests that an active metabolites is involved. No adverse effects were reported.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[How to evaluate the hemodynamic risk after myocardial infarction?].

The hemodynamic prognosis of myocardial infarction is determined, at medium and long term, by the function of the left ventricle. This is related to the infarct size, the dilatation and geometry of the ventricle secondary to left ventricular remodeling which often follows infarction. In addition to clinical criteria, the hemodynamic parameters which are essential for patient evaluation are the ejection fraction (by radionuclide or conventional ventriculography), rapidly progressive ventricular dilatation (by repeated echocardiography) and circulatory reserve from the exercise stress test data.

Angiocardiography↗
PubMed1992

Non-invasive identification of severe coronary artery disease in patients with long-standing diabetes mellitus.

OBJECTIVES: To detect severe coronary artery disease in asymptomatic middle-aged diabetic patients exposed to coronary artery disease risk factors. PATIENTS AND METHODS: Forty-four middle-aged patients (30 to 65 years of age) with a known duration of diabetes exceeding 10 years and at least one additional cardiovascular risk factor were studied. Patients were free of anginal chest pain and had a normal 12-lead ECG at rest. All patients underwent 24-hour ambulatory ECG, maximal bicycle exercise electrocardiography and intravenous dipyridamole thallium myocardial scintigraphy. If one of these 3 non-invasive tests revealed signs of myocardial ischaemia, a coronary angiography was performed. RESULTS: Non-invasive investigation yielded the diagnosis of myocardial ischaemia in 9/44 patients (20%). Six of the 9 patients had significant coronary artery stenoses (> 70% narrowing) and 5 exhibited severe triple-vessel disease. With dipyridamole thallium scintigraphy, the positive predictive value for diagnosis of coronary artery disease was optimal. CONCLUSION: In diabetic patients with additional coronary risk factors, periodical thorough clinical examination and resting ECG may fail to detect severe coronary disease. More sophisticated cardiovascular non-invasive tests should then be proposed as part of the periodical care of these patients.

Coronary Angiography↗
PubMed1992

[Apropos of acute changes in left ventricular filling induced by antihypertensive treatment].

The purpose of the study was to interpret the acute improvement in left ventricular (LV) filling induced by a new calcium channel blocker (SR 33 557) using Doppler echocardiography. Thirteen patients, 29 to 68 years old (mean 52) with mild to moderate hypertension were examined by Doppler echocardiography before and 4 hours after treatment (SR 33 557: 300 mg). The LV filling parameters, E, A, A/E, VTIM, VTIA, VTIA/VTIM, pressure half time (PHT) and isovolumic relaxation time (IRT) were measured. An index of left atrial pressure was obtained by measuring the mean pulmonary arterial pressure (PAP). The following hemodynamic parameters were also obtained: systolic blood pressure (SBP), heart rate (HR), PR interval (PR), stroke volume (SV) at aortic origin, total systemic resistances (TSR), pulse wave velocity (PWV) at thoracic descending aorta, LV end systolic stress (ESS), LV geometry (thickness/radius: th/r) and systolic function indices: mean VCF and contractility (mean VCF-ESS relationship). Following acute treatment, E and VTIM increased, A, VTIA and PHT did not change, and A/E, VTIA/VTIM ans IRT decreased, both significantly (p < 0.05). PAP did not change, HR, SBP, TSR, PWV, ESS decreased and PR increased both significantly (p < 0.05). LV geometry and systolic function did not change. No significant relationship was found between LV filling changes and changes in hemodynamic parameters. In conclusion, the acute increase in early LV filling induced by the calcium blocker treatment may be interpreted as the consequence of the improvement in LV relaxation in the absence of any change in left atrial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Assessment of exercise tolerance in chronic congestive heart failure.

In patients with chronic heart failure, exercise capacity is poorly related to cardiac hemodynamics, and peripheral circulation is an important determinant of exercise tolerance. The ability of the muscle vasculature to dilate is markedly impaired, in part, because of exaggerated neurohumoral activity increasing vascular wall stiffness. For this reason, increasing cardiac output is not sufficient to increase exercise capacity if not accompanied by improving vascular reactivity. The poor reliability and reproducibility of exercise tolerance assessed by maximal exercise duration or maximal attained work load (particularly on a treadmill) has led to widespread measurement of respiratory gas during exercise. Peak oxygen consumption (peak VO2), even if it is symptom-limited, has been shown to be a very reproducible criterion of exercise tolerance; moreover, because VO2 is the product of cardiac output and arteriovenous oxygen difference, it also has a qualitative hemodynamic significance. Ventilatory threshold can be determined before maximal exercise; however, problems of determination limit the practical value of this criterion. Unfortunately, peak VO2 lacks sensitivity to detect minor improvement or impairment of symptoms during daily life, although these are significant to the patient. Submaximal exercises have been proposed for this purpose and are currently being evaluated.

Exercise Test↗
PubMed1991

Ventilatory threshold during exercise in patients with mild to moderate chronic heart failure: determination, relation with lactate threshold and reproducibility.

Detection of the ventilatory threshold during exercise has been proposed in order to assess exercise tolerance in patients with chronic heart failure. The relation between the different methods of detecting the ventilatory threshold and the lactate threshold, however, and their reproducibility, have not really been assessed. Forty-three patients with chronic heart failure underwent an exercise test with respiratory gas analysis. A lactate threshold could be determined in 36 patients and a ventilatory threshold in 27 to 38 patients, depending on the method of determination of the ventilatory threshold. The greatest number of determinations (38) and the best correlation coefficient with the lactate threshold (r = 0.87 and 0.88, respectively) were obtained with the method of the ventilatory equivalent for oxygen and by averaging the different methods of determination. Reproducibility of the ventilatory threshold was only moderately good (r = 0.83) and less satisfactory than that of the peak oxygen uptake (r = 0.97). We conclude that unless the way of detecting the ventilatory threshold is improved in patients with chronic heart failure, the peak oxygen uptake will remain more reproducible.

Adult↗
PubMed1991

[Do antihypertensive agents change the incidence of cardiovascular complications of hypertension?].

The main aim of the treatment of hypertension is to reduce the incidence and severity of its complications. Despite some bias affecting the major clinical trials of diuretics and/or beta blockers, the results of the meta-analysis taking them into account demonstrate the effectiveness of the prevention of cerebrovascular complications and the less effective prevention of coronary complications. Progress can be hoped for as a result of new therapeutic categories (converting enzyme inhibitors, calcium channel inhibitors ...) and to a greater extent from new treatment strategies, involving better identification of "genuinely high risk" subjects.

Adrenergic beta-Antagonists↗
PubMed1991

[Left ventricular remodeling and ischemic heart diseases. Therapeutic possibilities].

Left ventricular modeling after myocardial infarction may be modified in three ways: firstly, by limiting the infarct size; secondly, by administering ACE inhibitors: these drugs limit infarct expansion and ventricular dilatation. They reduce the prevalence of secondary left ventricular failure and, in the animal, improve the prognosis. Glyceryl trinitrate also appears to be effective. The third therapeutic option is maintaining the patency of the artery responsible for the infarction, which has a beneficial effect on ventricular remodeling. The respective therapeutic indications of these three options are still a matter of discussion.

Adrenergic beta-Antagonists↗
PubMed1991

[Ventricular "remodeling" after myocardial infarction].

Cardiac failure is the principal medium-term complication of myocardial infarction. Changes in left ventricular geometry are observed after infarction, called ventricular remodeling, which, though compensatory initially, cause ventricular failure in the long-term. Experimental and clinical studies suggest that early treatment by coronary recanalisation, trinitrin and angiotensin converting enzyme inhibitors may prevent or limit the expansion and left ventricular dilatation after infarction, so improving ventricular function, and, at least in the animal, reduce mortality. Large scale trials with converting enzyme inhibitors are currently under way to determine the effects of this new therapeutic option. It would seem possible at present, independently of any reduction in the size of the infarction, to reduce or delay left ventricular dysfunction by interfering with the natural process of dilatation and ventricular modeling after infarction.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1991

[Properties of arteries, cardiac function and structure in chronic hypertension].

Hypertension is a condition which demonstrates the relationship between the properties of the left ventricle and arterial system. The spectrum of aortic impedence expresses the principal factors which oppose LV ejection into the initial aorta: 1) capacitive forces related to the viscoelastic properties of the arterial wall, directly proportional to its rigidity, 2) forces of inertia which increase with the acceleration of the blood and which are inversely proportional to the aortic cross sectional area, 3) reflection. With respect to a stroke volume which is usually normal, hypertension is characterised by: 1) an increase in mean aortic pressure (MAP), 2) with respect to the increase in MAP, an increase in systolic, late systolic and differential pressures. These changes in the level and morphology of aortic pressure are due to: a) the increase in systemic arterial resistances, a continuous expression of the spectrum of the module, b) an increase in the elastic forces (increased rigidity of the aorta related to increased pressure and structural wall changes) usually insufficiently compensated by a decrease in the inertial forces (aortic dilatation), c) an earlier return of the reflected pulse wave, well before the end of the anterograde wave. Overall, there is a relationship between the mass, the geometry (concentric hypertrophy) and pump function of the left ventricle and the properties of the arterial system expressed in terms of pulse wave velocity, characteristic impedence or the late systolic pressure/stroke volume ratio. The relationship is much closer than that of the properties of the LV and aortic pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1991

[Hemopericardium caused by coronary perforation during angioplasty. A surgical diagnosis].

A case of haemopericardium occurring during angioplasty of the left anterior descending artery complicated by an occlusive dissection is reported. The haemopericardium was diagnosed and evacuated during surgical myocardial revascularisation indicated by the failure of angioplasty. This complication, though rare, underlines the necessity of a real surgical stand-by for this procedure.

Angioplasty, Balloon, Coronary↗