Biomedical subjects

Y Leclerc

Publications and source records attributed to Y Leclerc.

At least 19 recordsLinked to original sources

PubMed1992

Effect of internal mammary artery dissection on sternal vascularization.

Internal mammary artery (IMA) dissection may cause sternal devascularization and ischemia resulting in sternal wound complication. To evaluate the effect of median sternotomy and IMA dissection on sternal vascular supply, sternal bone tomography was performed 7 days and 1 month after cardiac operation in 67 patients. Seventeen nondiabetic patients had single IMA grafts, 18 had double IMA grafts, and 12 had only saphenous vein grafts or valve replacement. Twenty diabetic patients were studied after any one of these operations. Seven patients were restudied 1 month after the operation. Sternal technetium-99m-methylene diphosphate tomography was performed. The sternum was visualized and focal zones of hypoactivity represented sternal hypoperfusion. The ratio of hypoactivity area over total sternal area was calculated for every patient. After median sternotomy without single or double IMA grafts, the averaged hypoperfusion ratio was 4% +/- 1% compared with 13% +/- 3% after single IMA grafts and 24% +/- 6% after double IMA grafts (p less than 0.0001). Diabetic patients without IMA, with single IMA, and with double IMAs showed hypoperfusion areas of 5% +/- 3%, 15% +/- 5%, and 23% +/- 9%, respectively, a result similar to that of nondiabetic patients. One month after operation the hypoperfusion area decreased to 2% +/- 2% (p less than 0.05) in restudied patients. Our results indicate that IMA dissection causes a significant although partial and temporary sternal ischemia, which is more severe after double IMA than single IMA mobilization and which may be incriminated in the development of sternal wound infection. This vascularization defect was not greater among patients with diabetes mellitus.

Body Mass Index↗

PubMed1992

[Salvage heart surgery after percutaneous mitral valvuloplasty].

Percutaneous mitral valvuloplasty (PMV) for selected patients with symptomatic mitral stenosis (MS) has been proposed as a safe alternative to open mitral commissurotomy (OMC) or mitral valvular replacement (MVR). Among 146 consecutive patients undergoing PMV from March 1987 to April 1990, 18 (12%) needed urgent (8) or delayed (10) (average 7 days) corrective surgery following PMV. There were 15 women and 3 men, with a clinical incapacity class II (3) or III (15), and with an intermediate risk for PMV according to echo score (mean = 8). The indications for corrective surgery were: massive mitral regurgitation due to tearing of the anterior leaflet (6), cardiac perforations (left atrium in 2, left ventricle in 3), PMV technical failure (5), severe atrial shunting (2). Operative procedures included MVR (14), cardiac wound suturing only (3), OMC (1). Operative mortality (30 days) was 22% (4/18), equally distributed among the urgent and delayed group. The causes of postoperative death were hemorrhage (2), severe cerebral ischemia (1) and sudden death (1). Compared to operative mortality after OMC (0/17.0%) or MVR (1/32, 3.1%) as the initial treatment for MS during the same time period, cardiac operation after failed or complicated PMV carried a significantly higher mortality (p = 0.004). Therefore, optimal patient selection and aggressive corrective surgery are necessary to decrease the PMV related mortality and morbidity.

Adult↗

PubMed1992

Prevention of herpes simplex virus infection by oral acyclovir after cardiac transplantation.

Infection with herpes simplex virus is common among immunosuppressed patients. In an attempt to prevent such infection, 58 patients (group 1) who underwent cardiac transplantation between 1987 and 1990 were given acyclovir (200 mg orally three times a day) prophylactically throughout their postoperative hospital stay (mean 22 days +/- 1 day). The patients' immunosuppressive protocol included cyclosporine, azathioprine and prednisone. The course of these patients was compared to that of 24 patients (group 2) who underwent cardiac transplantation between 1983 and 1986 but were not given prophylactic antiviral treatment postoperatively. The immunosuppressive protocol in these patients consisted of cyclosporine and prednisone. Herpes infection developed during the 1st year in 5 patients (9%) in group 1 and in 11 patients (46%) in group 2 (p < 0.05). The actuarial rates of freedom from herpes infection at 1, 6 and 12 months after transplantation were 100%, 98% +/- 2% and 95% +/- 3%, respectively, in group 1 and 82% +/- 7%, 58% +/- 11%, 53% +/- 11% in group 2. All viral infections were cutaneous or mucosal, except for one, which developed in a patient with pneumonia. All infections responded well to treatment, although one patient with an infected cornea was left with a permanent visual deficit. The authors conclude that prophylaxis of herpes simplex virus infection with acyclovir administered orally in the early postoperative period is effective in preventing viral infections during the 1st year after cardiac transplantation.

Acyclovir↗

PubMed1992

Cardiac surgery after failed percutaneous mitral valvuloplasty.

Percutaneous mitral valvuloplasty (PMV) has been proposed as a safe alternative to open mitral commissurotomy (OMC) or mitral valvular replacement (MVR) in selected patients with symptomatic mitral stenosis (MS). Among 146 consecutive patients who underwent PMV between March 1987 and April 1990, 18 (12%) needed urgent corrective surgery after the procedure. Of these 18 patients 16 were women and 2 were men. Three patients were of clinical incapacity class II and 15 of class III and were at an intermediate risk for PMV according to the echo score (mean score 8). The indications for corrective surgery were massive mitral regurgitation owing to tearing of the anterior leaflet (six patients), cardiac perforation (left atrium in two patients, left ventricle in three patients), technical failure of PMV (five patients) and severe atrial shunting (two patients). Operative procedures included MVR (14 patients), cardiac wound suturing only (3 patients) and OMC (1 patient). Operative mortality (within 30 days) was 22% (4 of 18 patients), distributed equally among patients needing urgent or elective surgery. When compared with the operative death rate after OMC (0%) and MVR (3.1%) as the initial treatment for MS during the same period, the rate for cardiac operation after failed or complicated PMV (22%) was significantly higher (p = 0.004). Therefore, optimal patient selection and aggressive corrective surgery are necessary to decrease PMV-related morbidity and death.

Adult↗

PubMed1992

Ultrastructural localization of endogenous albumin in human aortic tissue by protein A-gold immunocytochemistry.

The presence of endogenous plasma albumin in human aortas was demonstrated by immunocytochemical procedures. The protein A-gold approach, combining high resolution and specificity, was applied at the light and electron microscope levels to determine the in situ cellular and extracellular localization of albumin on tissue sections derived from normal and atherosclerotic human aortas. The distribution of albumin across the aortic wall interstitium was found to be uneven, with low to moderate staining intensities in the aortic subendothelial space, low intensities in the media, and high intensities around the vasa vasorum in the adventitia. Albumin was associated with collagen fibers as well as with the electron-dense material bordering the elastic laminae in both normal and pathologic tissues. Extracellular multilamellar structures were found to be characteristic of the necrotic areas of atherosclerotic aortas. These structures were intensely labeled for albumin, with the labeling being closely associated with the membranes. Numerous smooth muscle cell-derived and monocyte-derived foam cells were present in pathologic tissues, and some of their lysosomal compartments were labeled for albumin, suggesting an internalization and degradation of interstitial albumin by these cells.

Aged↗

PubMed1991

Percutaneous mitral valvuloplasty in surgical high risk patients.

Among 126 consecutive patients undergoing percutaneous mitral valvuloplasty, 34 were judged to be at high risk for surgery on the basis of age greater than 70 years (n = 13), New York Heart Association functional class IV (n = 11), ejection fraction less than or equal to 35% (n = 3), severe pulmonary hypertension (n = 7), need for associated coronary bypass (n = 4) or additional valve surgery (n = 20) or severe pulmonary disease (n = 3). Baseline features of the high risk group were substantially worse than those of the other patients: age (65 +/- 11 versus 49 +/- 12 years; p = 0.0001) and echocardiographic score (9.4 +/- 1.8 versus 8.2 +/- 1.5; p = 0.005) were higher, whereas cardiac output (2.9 +/- 0.9 versus 4.1 +/- 1.2 liters/min; p = 0.0001) and mitral valve area (0.9 +/- 0.4 versus 1.1 +/- 0.3 mm2; p = 0.002) were lower. Three high risk patients experienced technical failures and three others had major complications. Among the remaining 28 patients, 18 (65%) had a complete hemodynamic success, 4 (14%) an incomplete success and 6 (21%) hemodynamic failure. Stepwise logistic regression analysis retained echocardiographic score as the only factor independently predictive of success. The percent increase in mitral valve area also correlated with echocardiographic score (r = 0.51, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1991

Morbidity and mortality of reoperation for coronary artery bypass grafting: significance of atheromatous vein grafts.

Reoperation ('redo') for coronary artery disease shows a significant increase in morbidity and mortality compared to primary surgery. Some technical approaches have been advocated to decrease myocardial injury, presumably due to coronary artery embolization from atheromatous vein grafts. From 1984 to 1989, 321 'redo' operations were performed at the Montreal Heart Institute. Patients with patent and atherosclerotic vein grafts at preoperative coronary angiography (239 patients) were compared to those with normal or occluded grafts (82 patients). Perioperative myocardial infarction and death rates were 19% and 13%, respectively. They were particularly high among patients with three or more patent and atherosclerotic vein grafts at reoperation (32% and 29%, respectively). Among the 239 patients with patent atherosclerotic grafts, the results of three different surgical techniques were studied retrospectively. A first group of 66 patients had early ligation of patent atheromatous grafts before cardioplegia was administered by antegrade infusion during single aortic clamping for coronary anastomoses, and maintained for the confection of aortic anastomoses. In a second group of 35 patients, early ligation of diseased graft, antegrade cardioplegic delivery, and partial aortic cross clamping for aortic anastomoses of vein grafts was done. In the third group of 138 patients, venous grafts were not interrupted before antegrade cardioplegic infusion and partial aortic cross clamping for aortic anastomoses of vein grafts was used. No significant difference in hospital mortality or perioperative myocardial infarction rate was observed between the three groups of patients. Thus, the modified techniques so far recommended for repeat coronary artery bypass grafting, such as early ligation of patent atherosclerotic grafts, have failed to improve the early results of 'redo' operations.

Adult↗

PubMed1991

[Post-sternotomy mediastinitis: strategy of treatment].

To determine the incidence, the mortality, the risk factors and the most appropriate method for treatment of sternal infections, 9,742 charts were reviewed retrospectively of patients having undergone a sternotomy for cardiac surgery at the Montreal Heart Institute. One hundred and eleven sternal infections (1.1%) were identified: 55 (0.57%) superficial, 56 (0.57%) profound (mediastinitis). The treatment for these profound infections was either debridement, open or closed with drainage irrigation, pectoral flap closure-repair, or epiplooplasty closure. The risk factors for those patients experiencing profound infections were diabetes, obesity, length of the surgical intervention, the time spent in the operating room, and the duration of endotracheal intubation. Eleven of the 111 patients died. The average length of hospitalization were similar for those patients treated by pectoral flap repair and by the epiplooplasty closure. All patients (100%) treated by the epiplooplasty closure developed an epigastric hernia. Six cases of recurrent infection were observed in the group treated by debridement. The average hospital stay was shortened for those patients benefiting from the pectoral flap and epiplooplasty closures. A high incidence of mortality is associated with profound sternal infection. The methods of treatment are various. We recommend as treatment of choice, the pectoral flap closure because there is relatively low risks with this procedure, little to no recurrence of infection, a shorter hospital stay and this procedure does not provoke epigastric hernia.

Adult↗

PubMed1991

Some simple techniques helpful in ant research.

Eight simple techniques which may be helpful in ant research are presented. They facilitate: (1) collecting ground-nesting ants; (2) prompting ants to go out of their nest chambers; (3) introducing ants into a test tube; (4) recapturing ants during their mass escape in the laboratory; (5) keeping tidy foraging areas of artificial ant nests; (6) keeping high level of air humidity in foraging areas of artificial ant nests; (7) providing ants with water of improved quality; (8) cleaning artificial ant nests carved in plaster of Paris.

Animals↗

PubMed1991

Accelerated coronary atherosclerosis after cardiac transplantation: major threat to long-term survival.

Accelerated coronary atherosclerosis (ACA) has been documented at autopsy and was noted at coronary angiography in seven patients, 11 to 48 months after cardiac transplantation. To delineate the importance of this problem, the risk factors and the therapeutic approaches in 7 patients who had ACA after heart transplantation were compared with those in 28 patients free of ACA at annual coronary angiography. Ischemic cardiomyopathy was the preoperative diagnosis in all but one patient in the ACA group. The age of the transplant recipients, total myocardial ischemic times and arterial blood pressures at follow-up were similar in both groups. Donor age averaged 31 +/- 3 years in the ACA group and 22 +/- 1 years in patients free of ACA. Preoperative cholesterol, triglyceride and high-density lipoprotein levels were lower in ACA-free patients and the low-density lipoprotein level was higher. At the last follow-up visit, serum lipid levels were similar in both groups. The incidence of acute rejection and of infection was slightly, but not significantly, higher in patients with ACA. The actuarial survival of ACA patients 4 years after transplantation was 30% +/- 20% compared with 100% for patients free of ACA (p less than 0.01). Actuarial rates of freedom from ACA and from death due to ACA were 73% +/- 11% and 81% +/- 11% respectively. Stepwise discriminant analysis showed that older donors and higher pretransplant triglyceride levels were independently related to the development of ACA after cardiac transplantation. In conclusion ACA remains an important cause of late death after heart transplantation. Although therapeutic measures are limited, prevention should focus on strict control of serum lipid levels after transplantation.

Adult↗

PubMed1991

[Percutaneous mitral valvuloplasty. An analysis of the immediate results].

Percutaneous mitral valvuloplasty (PMV) was performed by the anterograde transseptal approach in 113 patients with symptomatic mitral stenosis. Mean age was 53 +/- 14 years and 89% were female. PMV resulted in a marked decrease in mitral gradient from 16 +/- 5 to 6 +/- 3 mmHg (p less than 0.0001) and a significant increase in mitral valve area from 1.09 +/- 0.36 to 2.12 +/- 0.83 cm2 (p less than 0.0001). An optimal hemodynamic result (gain in valve area greater than or equal to 25% and post-PMV valve area greater than or equal to 1.5 cm2) was obtained in 82 patients (73%). Multivariate statistical analysis selected as independent predictors of an optimal result: normal cardiac index (p = 0.0001), NYHA functional class less than 3 (p = 0.002), smaller left atrial diameter (p = 0.005), and echocardiographic score less than or equal to 8 (p = 0.01). The lowest frequency of optimal results was observed in patients with echocardiographic scores greater than or equal to 11 (20%). Three patients died (2.6%). All deaths occurred among the first 34 patients and none in the last 79 (p less than 0.05). Morbidity was also influenced by a learning curve effect. Mitral regurgitation developed or increased in severity in 38% of patients. This increase was mild (1 degree) in 85% of cases. Although the incidence of atrial shunting was high (76% by indicator dilution curve and 33% by oximetry), their magnitude was usually small (mean Qp/Qs 1.23 +/- 0.23) and lacked clinical significance. In conclusion, PMV provides excellent immediate hemodynamic results with low mortality and morbidity risks, specially once experience has been gained with this technique. Patients with echocardiographic scores less than or equal to 8 and smaller left atrial diameters, usually younger and less symptomatic, are the best candidates for PMV.

Adult↗

PubMed1990

Double-blind comparison of pefloxacin and cefazolin as prophylaxis in elective cardiovascular surgery.

A total of 162 patients (134 males and 28 females) scheduled for coronary artery bypass grafting (144) or valve surgery (18) were randomly assigned to receive, under double-blind conditions, either pefloxacin 400 mg iv or cefazolin 1.0 g 30 min before the surgical incision and then post-operatively 12-hourly x 4 or 6-hourly x 8, respectively. Positive per- and post-operative cultures were seen in 27 patients (11 pefloxacin, 16 cefazolin) and 47 micro-organisms were isolated: 34 per-operatively (21 pefloxacin, 13 cefazolin) and 13 post-operatively (4 pefloxacin, 9 cefazolin). There were five failures of prophylaxis (2 pefloxacin, 3 cefazolin): two early (less than 5 days: 1 pefloxacin, 1 cefazolin) and three late (greater than or equal to 5 days, 1 pefloxacin, 2 cefazolin) divided into (i) one major primary failure in the cefazolin group (1 cefazolin resistant Staphylococcus epidermidis mediastinitis); (ii) two minor primary failures, one in each group (Gram-positive sternal incision abscesses) and (iii) two secondary failures (1 cefazolin resistant Enterobacter cloacae and Pseudomonas aeruginosa UTI in the cefazolin group and one culture negative pneumonia in the pefloxacin group). Tolerance to both antibiotics was excellent. In our sample of patients, the efficacy and safety of pefloxacin was not different from those of cefazolin in prophylaxis in cardiovascular surgery.

Aged↗

PubMed1990

[The effect of cyclosporin on renal function following cardiac transplantation: should one lessen the toxicity?].

Between 1983 and 1988, 50 patients underwent cardiac transplantation at the Institut de Cardiologie de Montréal. During this period, four immunosuppression protocols were used, each including cyclosporine. A combination of cyclosporine and prednisone was used in the first 24 patients (group 1). Triple combination immunosuppression (cyclosporine, prednisone and azathioprine) was given perioperatively in 13 patients (group 2). The prophylactic use of rabbit antithymocyte globulin and late administration (4 days postoperatively) of cyclosporine to prevent early renal failure associated with cyclosporine therapy was chosen in 13 other patients (group 3). Owing to serious deterioration of renal function in 15 of the 24 group 1 patients, the serum creatinine levels reaching 255 +/- 51 mmol/L and the creatinine clearance 34 +/- 2 ml/min between 6 months and 4 years after transplantation, immunosuppression was modified to triple-combination therapy by the addition of azathioprine and a reduction of the serum levels of cyclosporine (group 4). Twelve of the 15 patients showed a substantial improvement in renal function from 3 to 18 months after these changes were introduced. No patient in groups 2 and 3 had late renal insufficiency, and in all group 3 patients renal function remained normal as in the immediate postoperative period. In conclusion, important modifications in protocol permitted a reduction of early and late renal failure due to cyclosporine after cardiac transplantation.

Adult↗

PubMed1989

Porcine versus pericardial bioprostheses: a comparison of late results in 1,593 patients.

From 1976 to 1988, 1,593 patients underwent valve replacement with a porcine (878 patients) or a pericardial bioprosthesis (715 patients). There were 701 aortic, 678 mitral, and 214 multiple-valve replacements. Follow-up was obtained for 1,559 patients (98%). Early mortality was 9% (79 patients) in the porcine valve group and 5% (37 patients) among patients with a pericardial valve (p less than 0.01). Late survival after replacement with porcine valves was 80% +/- 1% and 62% +/- 3% at 5 and 10 years, respectively. With pericardial valves, 5-year survival was 79% +/- 2%. Among valve-related complications, rates of freedom from thromboembolism, endocarditis, and hemorrhage after 6 years were similar for both valve groups. Freedom from reoperation at 6 years was also similar after aortic (96% versus 91%) or multiple-valve replacement (95% versus 88%). However, for mitral valve replacement, freedom from reoperation was significantly better with porcine valves than with pericardial valves at 6 years (92% versus 68%; p less than 0.001). This difference was mainly due to the Ionescu-Shiley valve, which accounted for 83% of primary tissue failures among pericardial bioprostheses implanted in the mitral position (10/12 patients). After 6 years, freedom from primary tissue failure of mitral valves was 92% +/- 2% with porcine and 70% +/- 11% with pericardial bioprostheses (p less than 0.0001). The degree of clinical improvement among survivors was similar with both valve types. Thus, in the aortic position, pericardial valves compare with porcine valves up to 6 years, whereas in the mitral position, the durability of the former is significantly less, mainly because of the suboptimal performance of the Ionescu-Shiley pericardial bioprosthesis.

Adolescent↗

PubMed1989

Diffuse lung uptake of technetium-99m sulfur colloid in malaria.

Diffuse lung accumulation of colloid was seen on liver-spleen imaging in a patient during the acute stage of vivax malaria. A repeat study was performed following successful therapy and showed complete disappearance of lung uptake. Possible mechanisms for this unusual observation are discussed, with the conclusion that this phenomenon is probably related to increased reticuloendothelial system activity, due to a malaria-induced increase in the pulmonary macrophages.

Adult↗

PubMed1988

Gallium-67 citrate accumulation in a mycotic popliteal artery aneurysm.

A 31-year-old man with bacterial endocarditis developed a mycotic popliteal aneurysm which presented clinically like an acute osteomyelitis. Bone and Ga-67 scanning played a major role in disclosing this unsuspected lesion. Various isotopic techniques proposed for the detection of mycotic aneurysm are reviewed. The potential usefulness of Ga-67 imaging in patients at risk of developing such lesions is discussed.

Adult↗

PubMed1988

Aortic valve replacement with the Carpentier-Edwards pericardial bioprosthesis: clinical and hemodynamic results.

From 1981 to 1987, 189 patients underwent isolated aortic valve replacement with the Carpentier-Edwards bovine pericardial bioprosthesis. There were 9 early deaths (30-day mortality of 4.8%) and 18 late deaths (3.3% pt-yr). After 5 years, the actuarial survival rate was 81.9%. All patients but one were followed for an average of 37 months after operation, and follow-up totaled 551 patient-years. Valve-related complications included 12 thromboembolic episodes (2.2%/pt-yr), 7 endocarditis (1.3%/pt-yr), 2 hemorrhages due to anticoagulation (0.4%/pt-yr), and 3 reoperations (0.5%/pt-yr). After five years, freedom from thromboembolic events was 91%, that from reoperation was 98%, and 87% for all valve-related complications. There was no primary tissue failure of the valve. Before operation, 55% of the patients were in functional Class III or IV, 97% of the survivors were in Class I or II after valve replacement. Hematological evaluation of 77 patients, an average of 18 months postoperatively, showed no clinically significant hemolysis. Postoperative hemodynamic studies in 28 patients showed mean aortic pressure gradients across the prosthesis at rest ranging from 24 mmHg with the smaller (19 mm) to 11 mmHg with the larger (25 mm and more) valves, and effective orifice areas ranging from 1.0 to 1.9 cm2, respectively. Thus, the Carpentier-Edwards pericardial bioprosthesis appears to be a reliable and hemodynamically effective substitute for replacement of the aortic valve.

Adult↗

PubMed1987

[Surgical treatment of ventricular tachycardia].

We present our clinical experience with 37 patients presenting with ventricular tachycardia who, between 1980 and 1986, underwent subendocardial resection, guided by per-operative mapping in 34 cases. An aneurysm of the left ventricle was present in 23 patients (62%), and an akinetic area in the remaining 14 patients. In every case the cause of ventricular tachycardia was an ischaemic heart disease. Prior to surgery, the global isotopic ejection fraction was 27 +/- 11% and the left ventricular end-diastolic pressure was 21 +/- 8 mmHg. The most common site of origin of the arrhythmia was the septum (26 cases, 77%). The mean area of resection was 26 +/- 16 cm2. Resection of a ventricular aneurysm was also performed in 23 cases, and 22 patients underwent coronary bypass. There were 4 early deaths (operative mortality rate : 10.8%) and 4 late deaths. The actuarial survival rate was 89 +/- 5% at 6 months and 72 +/- 9% at 24 months. One-half of the deaths was due to recurrence of the ventricular tachycardia. A post-operative electrophysiological study conducted in 30 patients proved negative in 28 (93%). Altogether, there were 6 immediate or late failures (16.2%) after a mean follow-up period of 18 months. The probability of a relapse-free, medication-free life or sudden death was 86 +/- 6% after 6 months and 82 +/- 7% after 24 months. The quality of life of the survivors war remarkable, since 86% of them (25/29 patients) remained in functional class 1 or 2 after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗