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Biomedical subjects

C Rioux

Publications and source records attributed to C Rioux.

At least 37 records · Page 2Linked to original sources
PubMed1995

[Changes in operative risk and its predictive factors in coronary surgery].

The operative risk of coronary bypass surgery has been reported by many surgical groups. Although the 1970's were characterised by a progressive decline in this risk related to improved surgical techniques and myocardial protection, the following decade saw a new rise in operative mortality. In order to assess this problem, the authors undertook a review of 3,632 consecutive cases of coronary bypass surgery (without any other procedure) from 1982 to 1991. The operative risk increased from 2% in 1982 to 7.7% in 1989 and was related to an increase in patients' age, in left ventricular dysfunction and in the number of emergency and redux operation. The development of interventricular cardiology in the last few years (angioplasty for double or triple vessel disease, thrombolysis in the acute phase of myocardial infarction) has also increased the number of patients operated as emergencies with a high operative risk. The reduction of the operative risk observed since 1989 is due to better overall management (pre, per and postoperative), especially of the high risk patients (patients over 70 years of age, women, left ventricular dysfunction, left main coronary stenosis, emergencies, reoperation). Although many variables indicating extramortality were found to be statistically significant (p < 0.05) on univariate analysis, multivariate analysis by two year periods showed the following independent prognostic factors of operative mortality: persistence of the concept of "emergency surgery" throughout the period under study and, from 1986, the appearance of gender and NYHA Class; and, from 1988, the factor "reoperation" with different values of "p" according to the years under consideration.

Analysis of Variance↗
PubMed1995

[Immediate and long-term results of replacement of the ascending aorta in aneurysm or dissection].

Between April 1974 and November 1992, 181 patients were operated for aneurysm (106) or dissection (75) of the ascending aorta. Eighty patients had replacement with a valvular conduit with reimplantation of the coronary arteries (Bentall procedure), 48 had aortic valve replacement with replacement of the supra-coronary ascending aorta and 53 underwent isolated replacement of the ascending aorta. Twenty-nine patients (16%) died in the postoperative period, mainly of myocardial or neurological complications. Univariate statistical analysis completed by logistic regression analysis revealed the following predictive factors of early death: NYHA Stage IV, angina, reoperation for haemorrhage or tamponade (all < 0.05). All surviving patients were followed up (total follow-up: 788 years; mean: 62 months; range: 1 to 181 months). There were 20 secondary deaths, 40% of which were related to complications of aortic valve replacement. The 5 and 9 year survivals were 76 and 70% respectively, perioperative mortality included, and 89% of patients were in NYHA functional Stage I. Analysis of survival data did not reveal any predictive factor of secondary death. Eight patients were reoperated at long-term. The operative mortality of replacement of the ascending aorta remains high, especially in cases of dissection. The long-term results seem excellent with a low reoperation rate. Late mortality seems mainly due to complications of aortic valve replacement.

Adolescent↗
PubMed1995

[Surgical treatment of aneurysms of the left ventricle. Immediate and long-term results. Apropos of a consecutive series of 121 cases].

From 1978 to 1992, 121 cases of postinfarction left ventricular aneurysm (99 males, 22 females, mean age 60 years) were operated on. The authors insist on a high rate of clinical arhythmogenicity (31.4%) and associated mechanical complications (21%). 76% of patients were in functional NYHA class III or IV. Resection was performed in 90% of patients, plication in 10%. 58% underwent coronary artery bypass grafting (1.7 graft/patient), 16% encircling ventriculotomy, 8% mitral valve replacement and 13% closure of ventricular septal defect. Operative mortality was 14.9% (10% when other mechanical complications where excluded). 5-year survival is 67.9%. Late cardiac deaths are as follow: left ventricular failure (1.8% A/P), Sudden death (1.4% A/P), Myocardial infarction (0.6% A/P). 82% of survivals are in functional NYHA class I or II. Only functional class NYHA III or IV is predictive of late death. We conclude that postinfarction left ventricular aneurysm remains a high risk complication especially when associated with other mechanical complications. When arhythmogenicity is present we suggest rhythmologic surgery and in all cases, complete revascularization.

Adult↗
PubMed1995

Aortic valve replacement for aortic stenosis in 200 consecutive octogenarians.

From 1978 to 1992, 200 consecutive patients aged between 80 and 90 years had aortic valve replacement for calcified aortic stenosis. Valve replacement was isolated in 187 cases (93.5%), and it was in combination with coronary bypass (n = 12; 6%), mitral valve replacement (n = 1; 0.5%) or surgery of the ascending aorta (n = 4; 2%). These 200 octogenarians represented 7.4% of the 2716 patients operated for aortic stenosis during the study period. One hundred and forty-eight of them (74%) were in NYHA class III or IV. Operative mortality was 11.5% (23 deaths) and the mean duration of hospitalization was 12.7 +/- 4.83 days. After discharge, all 177 surviving patients were followed up for a mean period of 2.8 +/- 2.1 years (range one month to 10.6 years). There have been 49 deaths during the follow up. At the end of the follow up, 127 of the 128 survivors (98.6) were in NYHA classes I or II. Actuarial survival at one, three and five years was 81.7%, 74.8% and 57.14% respectively, which is equivalent to the life expectancy for subjects of the same age without aortic stenosis. It is suggested that despite the increased, yet acceptable, operative risk, valve replacement in octogenarians is justified due to its beneficial effect on life expectancy and quality of life.

Actuarial Analysis↗
PubMed1994

Spectrometers for fast neutrons from solar flares.

Neutrons with energies exceeding 1 GeV are emitted in the course of solar flares. Suitable dedicated neutron spectrometers with directional characteristics are necessary for a systematic spectroscopy of solar neutrons. We report here a study of instruments based on the detection of proton recoils from hydrogenous media, with double scattering in order to provide directional information, and also a novel scheme based on the detection of radiation from the neutron magnetic dipole moment, permitting also directional detection of neutrons. Specific designs and detection systems are discussed.

Astronomy↗
PubMed1994

Surgery for aortic stenosis in elderly patients. A study of surgical risk and predictive factors.

BACKGROUND: Aortic stenosis is the most common valvular lesion occurring among elderly patients and has become extremely frequent because of changing demographics in industrialized countries. Surgical risk after the age of 70 has increased. The increasing older age of patients having surgery justifies an analysis of mortality predictive factors. METHODS AND RESULTS: Between 1976 and February 1993, we performed 2871 operations for aortic stenosis. This study concerns 675 patients (278 men and 397 women) who were > or = 75 years old. Mean age was 78.5 +/- 3 years. Associated lesions were found in 226 patients. A bioprosthesis was implanted in 632 patients (93.6%). Concomitant surgical procedures were performed in 133 patients. Surgical mortality was 12.4% (84 deaths). A longitudinal analysis has been carried out over four successive time periods to evaluate population evolution during these 17 years. Statistical analysis was performed on 46 variables. Multivariate analysis found age (P < .0001), left ventricular failure (P < .0001), lack of sinus rhythm (P < .01), and emergency status (P < .02) to be presurgical independent predictive factors of mortality. CONCLUSIONS: Risk-reducing strategy should both favor relatively early surgery to avoid cardiac failure and emergency situations and pay careful attention to the use of myocardial protection and cardiopulmonary bypass. Indications for surgery should remain broad since analysis failed to determine specific high-risk groups to be eliminated, and surgery remains the only treatment for aortic stenosis.

Age Factors↗
PubMed1994

[A study of predictive factors of the operative risk in the surgery of aortic valve stenosis in aged patients].

Aortic stenosis, the most extensive form of valvular disease in elderly subjects, has become very common because of demographic reasons in industrialised countries. The operative risk in patients over 70 years of age is significantly higher. The progressive rise in age of patients referred for surgery justifies this analysis of predictive factors of operative mortality. Between 1976 and February 1993, out of 2871 aortic valve replacements, 675 (278 men and 397 women) patients were over 75 years of age and were included in this study. The average age was 78.5 +/- 3 years. Associated pathology was present in 226 patients. A bioprosthesis was chosen in 632 cases (93.6%). An associated surgical procedure was required in 133 cases. The operative mortality was 12.4 +/- 1.3% (84 deaths). Longitudinal analysis was performed for 4 successive periods to assess the outcome of the study population over the 17 years. A statistical study was made of 50 variables and multivariate analysis showed age (p < 0.0001), left ventricular failure (p < 0.0001), non sinus rhythm (p < 0.0005) and emergency procedures (p < 0.02) to be independent preoperative predictive factors of mortality. In order to reduce this risk, the authors recommend early surgical referral to avoid emergency procedures and cardiac failure, and increased efforts of myocardial protection during cardiopulmonary bypass. Despite the risk, surgery is the only radical treatment of aortic stenosis, including elderly patients.

Age Factors↗
PubMed1993

[Long-term results of Carpentier-Edwards and Saint-Jude Medical mitral valve prosthesis].

Between 1980 and 1985, 239 patients underwent mitral valve replacement with a Saint Jude Medical (130) or Carpentier-Edwards (109) prosthesis alone or associated with correction of tricuspid regurgitation. Age, NYHA grade and pulmonary artery pressures were comparable in the two groups. Two hundred and seventeen of the 221 survivors were contacted (98.6% follow-up): the long-term prosthesis-related mortality was 35% in the Saint Jude Medical group and 22.5% in the Carpentier-Edwards group. The global survival at 9 years was 82% in the Saint Jude Medical group but only 63% in the Carpentier-Edwards group. The actuarial thromboembolic-free rate at 9 years was 96% in the Saint Jude Medical and 86% in the Carpentier-Edwards group (not significant). Two Saint Jude Medical and one Carpentier-Edwards bioprosthesis thrombosed--a linear rate of 0.2% PY and 0.1% PY respectively. Furthermore, there was no significant difference in the actuarial rate of haemorrhagic complications between the two groups. Endocarditis and valve degeneration were more common in the Carpentier-Edwards group (1.3% and 1.6% PY respectively). Over the 9 year period, the thromboembolic complications of the Saint Jude Medical and Carpentier-Edwards prostheses were similar in actuarial and linear terms. With respect to long-term mortality and morbidity, the results with the Saint Jude Medical valve seem to be superior to those of the Carpentier-Edwards bioprosthesis.

Actuarial Analysis↗
PubMed1993

[20 years of mitral valve replacement. Development of a patient profile and operative mortality].

Between 1971 and 1991, 1,179 mitral valve replacements (MVR) were carried out in 1,134 patients. The sex ratio was stable over this period (0.7 men/women) whereas the average age of the patients increased by 10 years (50 years in 1971, 61 years in 1991). Since 1980, patients over 60 years of age represent about 60% and those over 70 years of age 16 to 22% of the population. The functional status of the patients has tended to be less severe, the NYHA stages III and IV which were initially preponderant, only represent 50 to 60% of patients operated nowadays. This reduction in the severity of symptoms is reflected in the average value of the cardio thoracic index which was 60 in 1971 and 54.8 in 1991. Similarly, the mean pulmonary artery pressures (measured in 823 patients, 69.8%) have decreased from 37.4 mmHg in 1971 to 29.9 mmHg in 1991. Rheumatic fever has tended to be replaced by degenerative etiologies which, since 1985, represent 40 to 50% of cases. Ischemic mitral regurgitation rare before 1980, is more common, presently making up 5 to 15% of MVR cases. In relation with the etiological changes mitral stenosis is giving way to mitral regurgitation as the commonest valve lesion (40 to 50% of cases in 1991). The annual operative mortality is lower (6 to 8%) than in 1982, despite the increasing number of emergency cases (7 to 10% of cases since 1985). The number of MVR with associated tricuspid valve repair has decreased with respect to isolated MVR or associated with aortocoronary bypass grafting. The only constant feature is the death rate due to myocardial dysfunction which remains over 50% whereas mortality related to the prosthetic valves varied over the years.

Age Factors↗
PubMed1992

[Immediate and long-term results of 790 mitral valve replacements].

A total of 790 patients underwent isolated (N = 520) or mitral valve replacement associated with a tricuspid valve procedure for lesions excluding post-myocardial infarction mitral regurgitation. The mean age was 54 years: the sex ratio was 1.9 +/- 1.1, female/male. Three hundred and four patients (38.5%) were in the NYHA functional class II and 406 patients (61.5%) were in classes III or IV. The operative mortality was 9.7% (77 patients). The factors associated with a high operative risk were, on multifactorial analysis: double valve replacement, age over 70 years, NYHA class IV, aortic clamp time over 68 minutes and the presence of mitral regurgitation. Seven hundred and four of the 713 survivors were contacted (98.7% follow-up). The average follow-up period was 5.05 years (range 11 to 219 months) giving a total of 3,997 patient-years. The 5 and 10 year actuarial survival rates were 74.7% and 64.7% respectively. The presence of a tricuspid lesion requiring surgical correction, a high NYHA classification and the presence of mitral regurgitation were poor prognostic factors of long-term survival. Three hundred and sixteen of the 533 survivors at the time of the inquiry were in NYHA class I (59.3%), 188 in NYHA class II (35.3%) and 29 in NYHA class III or IV (5.4%). Mitral valve replacement should be considered early as the immediate and long-term results are closely related to the preoperative myocardial function.

Actuarial Analysis↗
PubMed1991

[Mitral valve replacement in postinfarction mitral insufficiency. Immediate and long-term results apropos of a series of 39 surgically-treated patients].

Thirty nine patients, mainly males (84.6%) with an average age of 66 years underwent mitral valve replacement for postinfarction mitral regurtation between March 1971 and December 1987. Twenty four were in Class IV of the NYHA Classification, 9 in Class III and 6 in Class II. All had a history of myocardial infarction predominantly of the inferior wall. The 33 preoperative coronary angiogrammes showed 13 patients with triple vessel disease, 15 with double vessel disease and 5 with single vessel disease. At operation, 13 patients had ruptured papillary muscles; acute dysfunction was observed in 16 and chronic in 10 patients. The hospital mortality was 36%; over three quarters of deaths were due to myocardial dysfunction. Twenty two patients had an associated myocardial revascularisation procedure with mitral valve replacement. All 25 survivors were followed up for an average of 2.3 years (94 patient-years). The 5 year actuarial survival (operative mortality included) was 55% and 77% of the 17 survivors are in Stages I or II of the NYHA Classification. The quality of these long-term results justifies surgery despite the high operative risk.

Actuarial Analysis↗
PubMed1991

[A comparative evaluation of a prosthetic operation and balloon valvuloplasty in aortic valve stenosis in elderly people].

The results of surgical treatment of aortic stenosis (AS) in elderly patients were studied in a group of 602 patients aged from 70 to 90 years (average age 74.6 years) chosen from a total number of 1,643 persons who underwent operation for AS in 1975-1988. Total operative mortality with consideration for mortality connected with combined interventions was 11.4%, in the group of isolated prosthetics it was 10.4%. The late-term results were appraised in 96.6% of patients (in 3.6 years, on the average). According to actuarial charts, survival after 3 years was 75.9%, after 5 years--66.7%, and after 7 years--55.6%. There was no difference in the survival values of recipients of biological and mechanical prostheses. Significant improvement of the functional condition was noted (96.5% of patients belonged to NYHA classes I and II). Demographic and epidemiological studies showed this pathology in the elderly to be a new problem of surgery. Surgical treatment is justified by the quality of the results, prolonged survival, and an admissible risk level even at the age of 80-90 years. Comparison with the results of aortic balloon valvuloplasty studied on basis of a rich literature review shows these to be much poorer. On the whole, only surgery may be the real method of treatment allowing effective removal of AS. The operation can be carried out even on very old patients if there are no substantiated contraindications on the part of the brain and the patient's general condition.

Actuarial Analysis↗
PubMed1991

[Results of surgical treatment of calcified aortic valve stenosis in 80-year-old patients].

The authors discuss surgical treatment of 67 patients for aortic stenosis in 1978-1988. Their ages ranged form 80 to 90 years. In a relatively low operative risk (8.9% mortality) the results provide evidence of marked improvement both in the functional condition (96% of patients are related to the NYHA classes I and II) and in survival (3-year survival 78.2%). The results of balloon valvuloplasty were much poorer. The indications for aortic valvuloplasty are very limited and determined with difficulty.

Aged↗
PubMed1991

[Autologous transfusion in heart surgery (apropos of 74 patients)].

The present study uses three techniques of autotransfusion in heart surgery under ECC: peroperative and post-ECC transfusion of blood removed after induction of anaesthesia (group I: 25 patients); postoperative transfusion of extravasated thoracic blood (group II: 24 patients) and a combination of the two (group III: 25 patients). Postoperative bleeding was comparable in all groups; A subset likely to haemorrhage made up of patients who had lost more than one litre of blood was isolated and demonstrated a reduction in the number of homologous red cell concentrates needed for the autotransfused population in comparison with the controls (2.4 +/- 2.6 vs 5.7 +/- 3.5 red cell concentrates, p less than 0.05) and was particularly marked in Group II patients who received 1.9 +/- 2.2 homologous red cell concentrates. None of the techniques caused any side-effects. Combination of the two autotransfusion techniques in heart surgery does not secure any additional advantages compared with postoperative autotransfusion alone.

Blood Transfusion, Autologous↗
PubMed1991

[Aneurysm of a saphenous vein aortocoronary shunt caused by fissure syndrome].

The authors report a new case of an aneurysm of a saphenous vein aorto-coronary shunt. The aneurysm manifested itself by a fissure syndrome in a man 48 years of age, 9 years after myocardial revascularization surgery. A chest X-ray revealed a right paracardiac opacity, and two-dimensional ultrasound picked up an expansive, hypoechoic mass. The diagnosis was confirmed by coronary artery angiography. The aneurysm was opened up and the proximal anastomosis sutured. After a follow-up period of 30 months, the patient is asymptomatic.

Aneurysm↗
PubMed1990

Red blood cell polyamine level changes following heart transplantation in man.

Follow-up of orthotopic heart transplanted patients has revealed the existence of abnormally high red blood cell (RBC) spermidine (Spd) levels during the first two months after surgical procedure (A-period). From the third month after heart transplantation (B-period), RBC Spd concentrations went back to normal values in early cardiac rejection (ECR) patients. During A- and B-periods, significantly higher Spd levels and Spd/Spm ratios were observed in late cardiac rejecting (LCR) patients than in ECR ones. The lack of a direct relationship between the histological grade of rejection and RBC Spd levels leads us to consider these polyamine blood levels as a new biological instrument in the diagnosis of heart rejection.

Chromatography, High Pressure Liquid↗
PubMed1990

[Myocardial infarction and massive biventricular thrombosis during thrombocytopenia induced by pentosan polysulfate and heparin].

Many cases of immuno-allergic thrombocytopenia complicated by serious thromboembolism induced by heparin or other heparinoids such as pentosan polysulphate have been reported. This case is of interest for two reasons: first of all, it was induced by pentosan polysulphate and then reactivated by secondary administration of heparin; secondly, it was complicated successively by an infero-apical myocardial infarction with probable spontaneous lysis of a coronary thrombosis because coronary arteriography performed one month later was normal, and then by massive biventricular thrombosis requiring surgical thrombectomy under cardiopulmonary bypass. Tests of platelet aggregation were positive to standard heparin and to several low molecular weight fractions. The outcome was favorable when the responsible substances were withdrawn.

Blood Coagulation Tests↗