Biomedical subjects
Publications and source records attributed to Y Leclerc.
Propionibacterium acnes endocarditis is a rare disease. A case of prosthetic valve endocarditis involving P acnes complicated by multiple mycotic aneurysms is reported. A brief review of the literature is presented.
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Allograft coronary artery disease is a major threat to long-term survival after cardiac transplantation. It has been suggested that hyperlipidemia plays a major role in allograft coronary disease. The objective of the present study was to evaluate the effect of a lipid-lowering intervention with diet and drug therapy after cardiac transplantation. Forty-six patients who underwent transplantation between 1988 and 1991 and who were treated with the American Heart Association phase 1 diet and an HMG coenzyme A reductase inhibitor (lovastatin or simvastatin) when low-density lipoprotein cholesterol levels were higher than 3.4 mmol/L were compared with 35 untreated patients having transplantation between 1983 and 1988. Annual coronary angiograms were obtained in both groups. Cholesterol, triglyceride, and low-density lipoprotein levels were significantly lower in the treated group. Actuarial survival and event-free survival (survival free from allograft coronary artery disease) were similar in both groups. Low-density lipoprotein levels lower than 3 mmol/L at the last follow-up had a positive effect on event-free survival. The cholesterol-lowering intervention was not effective in decreasing the prevalence of allograft coronary artery disease. This study suggests that more aggressive measures to lower low-density lipoprotein levels may be necessary to significantly affect allograft disease. Clinical trials should be developed to address this hypothesis.
A prospective, randomized study was performed in 200 patients undergoing coronary artery bypass grafting to compare the myocardial protection obtained with intermittent antegrade warm versus cold blood cardioplegia. Preoperative and surgical characteristics of the two cohorts were similar. Intermittent antegrade infusion of warm blood cardioplegia failed to achieve sustained electromechanical arrest of the heart in 13%. The only difference in clinical outcomes was the more frequent spontaneous return to sinus rhythm after the unclamping of the aorta in the warm group (88% versus 70%, p = 0.002). Mortality (1% each) and myocardial infarction (2% and 4%) rates were similar. Rates of increase in serum activity of the isoenzyme of creatine kinase (CK-MB), CK-MB mass concentration, and cardiac troponin-T level as well as total release of troponin T were significantly lower in the warm group, and fewer patients in this group had a clinically significant increase in serum CK-MB mass (20% versus 39%, p = 0.005) and troponin T (20% versus 56%, p = 0.00001). Thus, intermittent antegrade warm blood cardioplegia is appropriate and clinically safe; the lower release of biochemical markers of myocardial damage suggests improved protection during first-time coronary artery bypass grafting.
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Balloon mitral commissurotomy (BMC) was performed in 113 patients. Of these patients, 27 (24%) (25 women and 2 men, aged 49 +/- 13 years) had recurrent mitral stenosis 13 +/- 6 years (range 5 to 29) after surgical commissurotomy. Eleven patients (41%) were considered at high risk for surgery. BMC resulted in an increase in mitral valve area from 1.1 +/- 0.3 to 1.9 +/- 0.7 cm2 (p < 0.0001), and a decrease in mean mitral gradient from 16 +/- 7 to 6 +/- 3 mm Hg (p < 0.0001). An optimal result of BMC (increase in valve area > or = 25% with a post-BMC valve area > or = 1.5 cm2) was obtained in 18 patients (67%). The results did not differ from those observed in the 86 patients of our entire series without prior surgical commissurotomy. Patients with an optimal result of BMC had a more recent surgical commissurotomy and lesser morphologic alterations of the mitral valve than did those with a nonoptimal result. Patients with echocardiographic scores < 10 had an 80% success rate of BMC; however, this rate decreased to 29% for those with scores > or = 10. One patient (4%) died from a cerebrovascular accident. Clinical follow-up at 1 year showed persistent clinical improvement in 89% of patients with an optimal result of BMC; 72% were in New York Heart Association class I and 17% in class II.(ABSTRACT TRUNCATED AT 250 WORDS)
Of 280 patients treated by balloon mitral commissurotomy (BMC) between 1987 and 1991, 28 (10%) were > or = 70 years old. Two patients with associated significant aortic stenosis were excluded from the study. Older patients more often were in New York Heart Association class III or IV (84 vs 67%; p < 0.007) and atrial fibrillation (61 vs 36%; p < 0.0001), and had a higher echocardiographic score (9.3 +/- 2 vs 8 +/- 1.6; p < 0.0004) and a lower baseline cardiac index (2.1 +/- 0.6 vs 2.4 +/- 0.6 liters/min/m2; p < 0.03) than younger ones. Baseline mean pulmonary pressure (37 +/- 11 vs 34 +/- 12 mm Hg), transmitral gradient (14 +/- 4 vs 14 +/- 5 mm Hg) and valve area (1.0 +/- 0.4 vs 1.1 +/- 0.3 cm2) were not different between older and younger patients (p = NS). Acute complications during the procedure (including cardiac perforation, embolism, severe mitral regurgitation and surgical atrial shunt), and 30-day mortality after BMC were more frequent in older than younger patients (27 vs 9% [p < 0.01], and 12 vs 0.8% [p < 0.005], respectively). A complete success, defined as a mitral valve area increase > 25% and postmitral valve area > 1.5 cm2 was obtained in 16 of the 22 older patients (72%) with the completed procedure (compared with 81% of younger ones; p = 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)
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University of Wisconsin (UW) solution has been reported to enhance myocardial preservation in heart transplantation. To evaluate the effects of UW solution on coronary artery endothelial function, we designed experiments to compare UW solution with a standard crystalloid hyperkalemic cardioplegic solution (CHCS). Isolated rat hearts were studied in a modified Langendorff apparatus for coronary endothelial function. Groups 1 and 2 were perfused with 4 degrees C CHCS (24 mmol/L of KCl) and UW solution, respectively, for 10 minutes at a pressure of 80 cm H2O, whereas group 3 underwent warm ischemia for 10 minutes. Groups 4 and 5 were perfused with and stored for 4 hours in cold (4 degrees C) CHCS and UW solution, respectively. Group 6 underwent 4 hours of topical cooling (4 degrees C) without any cardioplegic perfusion. All groups had 6 hearts each. Endothelium-dependent relaxation and endothelium-independent relaxation of the coronary arteries were tested by infusing 5-hydroxytryptamine (5HT) (10(-6) mol/L) and sodium nitroprusside (10(-5) mol/L), respectively, before and after perfusion with and storage in one of the two cardioplegic solutions. The coronary vasodilatation induced by 5HT and sodium nitroprusside was not altered in hearts perfused with (group 1) or perfused with and stored in CHCS (group 4). Coronary flow increase after 5HT infusion was significantly decreased in hearts perfused with (group 2) (before, 35% +/- 10%; after, 13% +/- 10%; p < 0.01) or perfused with and stored in UW solution (group 5) (before, 34% +/- 5%; after, -5% +/- 12%), indicating severe endothelial dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)
The excellent long-term results with the internal mammary artery for coronary artery bypass grafting have prompted the search for other conduits with similar characteristics. From December 1989 to December 1991, the right gastroepiploic artery (RGEA) has been used as an in situ graft to the posterior descending coronary artery in 51 patients at the Montreal Heart Institute. The patients' age averaged 50 +/- 11 years. Three-vessel coronary artery disease was present in 41 patients and two-vessel disease in the remaining 10 patients. In all but 1 patient, bilateral internal mammary artery grafting was performed in addition to RGEA grafting. The number of grafts per patient averaged 3.2 +/- 0.8. There was no operative mortality. Morbidity was minimal with only myocardial infarction and a pleural effusion in 1 patient. In 1 patient, a splenectomy had to be performed because of iatrogenic tear during dissection of the RGEA. The average hospital stay was 8.2 +/- 2.6 days. Enteral nutrition was resumed on average 2 days after operation. Angiographic evaluation of RGEA grafts was performed before discharge or within the first month after surgery in 31 patients. In 28 patients (28/31, 90%) the RGEA graft was patent, two grafts were occluded, and in the remaining patient, the graft could not be visualized due to technical difficulties during angiography. A second angiographic evaluation was performed in 5 patients, 1 year after operation. Four RGEAs were patent and 1 was occluded. Clinical follow-up averaged 4 months (range 1 to 15 months).(ABSTRACT TRUNCATED AT 250 WORDS)
The prevalence and natural history of pseudo-aneurysm (PA) following Bentall procedure has not been established. To determine the follow-up of such patients, we report our experience with magnetic resonance imaging (MRI) used since 1988. At first, spin-echo exam, PA was suspected in 19 patients among 27 patients who underwent aortic valve and ascending aortic replacement between 1980 and 1991. Mean PA diameter was < 4 cm in 13 patients (group 1) and > or = 4 cm in six patients (group 2). Two patients of group 1 were lost at follow-up while two others died after the first spin-echo exam, one death being related to PA formation. Repeated MRIs were done in nine patients of group 1 and all patients of group 2 averaging respectively 2.2 +/- 1.1 exams per patient for group 1 and 1.8 +/- 1.1 for group 2. PA regressed in six patients of group 1 and one patient of group 2 thus suggesting thrombosed PA or postoperative haematoma. PA remained stable in two patients of group 1 and one patient of group 2. One patient of group 1 in whom PA increased at follow-up died suddenly. Four patients of group 2 required surgical correction of their PA. One of these patients died of massive hemoptysis 2 months following reintervention. Recently, addition of cine MRI allows visualization of turbulent flow within the PA thus increasing MRI specificity for PA diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)
The excellent results with the internal thoracic artery for coronary artery bypass grafting have prompted the search for other arterial conduits. From November 1991 to February 1992, 18 patients underwent coronary artery bypass grafting with the use of inferior epigastric artery grafts. Patients' ages averaged 52 +/- 9 years. Bilateral internal thoracic artery grafts were used in 17 patients (17/18, 94%) and a free graft with one inferior epigastric artery was used in each patient. The inferior epigastric artery grafts were anastomosed to the right coronary artery (n = 9), a marginal circumflex artery (n = 4), and to a diagonal artery (n = 5). Three patients had abdominal wound complication related to harvesting of the inferior epigastric artery. Immediate postoperative angiographic evaluation of inferior epigastric artery grafts showed that eight grafts were patent (8/14, 57%). Four of the occluded inferior epigastric arteries were grafted to the right coronary artery and one to the second marginal circumflex coronary artery. Because of the low patency rate of inferior epigastric artery grafts, a word of caution is necessary in the selection of patients. At the present time, the inferior epigastric artery appears to be an interesting alternative only in patients who have no other available conduits.
Mediastinitis-related right ventricular rupture is an unusual but potentially life-threatening complication of cardiac operations. Between January 1981 and December 1990, a total of 10,182 patients underwent heart operations for ischemic, valvular, and congenital heart disease at the Montreal Heart Institute. Forty-eight patients (0.5%) had postoperative mediastinitis necessitating surgical exploration and sternal debridement. The mediastinum was left open for daily irrigation with povidone-iodine and chest reconstruction was postponed. During treatment, seven patients (0.07%) had right ventricular rupture necessitating immediate surgical repair. All had ischemic heart disease before the operation. There were five women and two men, ages ranging from 52 to 65 years (mean 58 +/- 5 years). Surgical repair consisted of autologous patch covered with omentoplasty assisted with cardiopulmonary bypass. Two patients died, one during the operation of massive hemorrhage and the other 10 days after the operation of uncontrolled sepsis. Five patients survived 2 to 29 months (mean 23 +/- 10 months) after right ventricular rupture, with an overall survival of 71%. Obesity was more frequent in the patients with right ventricular rupture and was found to be a significant risk factor (multivariate analysis, p < 0.05, relative risk 3.22). Histologic examination of the right ventricle in the patient who died after a successful repair revealed fatty infiltration of the right ventricular wall. This may have predisposed the patient toward ventricular rupture. In conclusion, right ventricular rupture, an unusual event in heart surgery, is related to open sternal debridement. Favorable outcome of this complication depends on immediate surgical management, autologous repair, and the use of omentoplasty.
The prevalence and natural history of pseudoaneurysms (PA) following Bentall procedure has not been established. To determine the follow-up of PA in patients, the authors report their experience with magnetic resonance imaging (MRI) since 1988. Spin-echo technique suspected PA in 19 of the 27 patients who underwent aortic valve and ascending aortic replacement between 1980 and 1991. Mean PA diameter was less than 4 cm in 13 patients (group 1) and at least 4 cm in six patients (group 2). Two patients in group 1 were lost at follow-up while two others in this group died after first spin-echo examination (one death was related to PA formation). Repeated MRIs were thus possible in nine patients in group 1 and in all patients in group 2, averaging 2.2 +/- 1.1 examinations per patient for group 1 and 1.8 +/- 1.1 for group 2. PA assessed in six group 1 patients and one group 2 patient suggested thrombosed PA or postoperative hematoma. PA remained stable in two group 1 patients and one group 2 patient. One patient from group 1, in whom PA increased at follow-up, died suddenly. Four patients in group 2 required correction of PA, which had increased in diameter. Recently, addition of cine MRI has allowed visualization of turbulent flow within PA, thus increasing MRI specificity for PA diagnosis. In conclusion, MRI constitutes a reliable noninvasive imaging technique for diagnosis and follow-up of PA after Bentall repair.
A patient, aged 26, had a large parietal tumor, clinically revealed by intracranial hypertension and left sized paresthesia. Removal of tumor was followed by a rapid recurrence. Rhabdomyosarcoma was diagnosed on the second surgical specimen. These tumors are rare in the central nervous system. They occur mostly, though not exclusively, in young adults. Their prognosis is poor and their histogenesis is still unclear.
Perioperative induction of immunosuppressive treatment with rabbit antithymocyte globulin (RATG) and late introduction of cyclosporine was used in a group of 77 patients to prevent early renal dysfunction related to cyclosporine. Peak value in plasma creatinine during hospitalization for transplantation averaged 148 +/- 49 mmol/L in patients treated with RATG compared with 215 +/- 21 mmol/L in 39 patients initially treated without RATG induction (P = 0.01). Of patients treated with RATG, 65 +/- 6% remained free from acute rejection at six months versus 40 +/- 8% of untreated patients (P = 0.03). Rates of freedom from infection, from allograft coronary artery disease and from cancer are similar in both groups. Actuarial survival rates were identical in the two groups. The total number of lymphocytes, the percentage of T lymphocytes and of helper T cells were significantly lower when RATG was used. In conclusion, RATG prophylaxis given immediately after transplantation was well tolerated without complication and resulted in adequate immunosuppression to allow delayed introduction of maintenance treatment with cyclosporine.
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.
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.