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Biomedical subjects

M Carrier

Publications and source records attributed to M Carrier.

At least 37 records · Page 2Linked to original sources
PubMed2002

Early reoperation for iatrogenic left main stenosis after aortic valve replacement: a perilous situation.

BACKGROUND: Iatrogenic left main coronary artery (LMCA) stenosis secondary to direct ostial cannulation during aortic valve replacement still occurs and is a morbid situation due to the difficulties of early reoperation and in providing adequate myocardial protection. METHODS: A retrospective analysis was performed and identified seven patients with an iatrogenic LMCA stenosis, after 2158 aortic valve replacements (AVR) (0.3%) in our institution since 1987. RESULTS: All patients with LMCA stenosis after AVR had undergone direct ostial cannulation with self-inflating balloon cannulas at the time of AVR. At reoperation for LMCA stenosis, severe ischemia developed in one patient and injury to cardiac structures occurred in four patients. Four patients suffered a perioperative myocardial infarction and congestive heart failure developed in two patients at late follow-up. CONCLUSIONS: LMCA stenosis following coronary ostial cannulation at the time of AVR is a rare yet morbid complication. Reoperation for this condition is fraught with a high operative morbidity rate and poor long-term outcome. Prevention of this complication is quintessential, avoiding ostial cannulation with self-inflating balloons.

Adult↗
PubMed2001

Safety, tolerability, and efficacy of cyclosporine microemulsion in heart transplant recipients: a randomized, multicenter, double-blind comparison with the oil-based formulation of cyclosporine--results at 24 months after transplantation.

BACKGROUND: The widespread use of cyclosporine has improved the survival of cardiac transplant patients as a result of reduced morbidity and mortality from rejection and infection. The original oil-based form of cyclosporine demonstrated unpredictable absorption resulting in an increased frequency of acute and chronic rejection in patients with poor bioavailability. The primary end. points of the present, prospective, randomized multicenter, double-blind trial were to compare the efficacy of the micro-emulsion form of cycolsporine (CsA-NL) with the oil-based formulation as determined by cardiac allograft and recipient survival and the incidence and severity of the acute rejection episodes and to determine the safety and tolerability of CsA-NL compared with Sandimmune CsA-(SM) in the study population. The 6-month analysis of the study showed reduced number of CsA-NL patients requiring antilymphocyte antibody therapy for rejection, fewer International Society of Heart and Lung Transplantation grade > or =3A rejections in female patients and fewer infections. Our report represents the final analysis of the results 24 months after transplantation. METHODS: A total of 380 patients undergoing de novo cardiac transplants at 24 centers in the United States, Canada, and Europe were enrolled in this double-blind, randomized trial evaluating the efficacy and safety of CsA-NL versus CsA-SM. Acute allograft rejection was diagnosed by endomyocardial biopsy and graded according to the International Society of Heart and Lung Transplantation nomenclature. Kaplan-Meier analysis and Fisher's exact test were used for comparisons between groups. RESULTS: After 24 months, allograft and recipient survival were identical in both groups. There were fewer CsA-NL patients (6.9%) requiring antilymphocyte antibody therapy for rejection than in the CsA-SM-treated patient group (17.7%, P=0.002). There were fewer discontinuations of study drug for treatment failures in the CsA-NL groups (7; 3.7%) compared with the CsA-SM group (18; 9.4%, P=0.037). The average corticosteroid dose was lower in the CsA-NL group (0.37 mg/kg/day) compared with the CsA-SM group (0.48 mg/kg/day, P=0.034) over the 24-month study period. Overall, there was no difference in blood pressure or creatinine between the two study groups. CONCLUSIONS: The final results of this multi-center, randomized study of two forms of cyclosporine confirmed that there were fewer episodes of rejection requiring antilymphocyte antibodies and fewer study discontinuations for treatment failures in CsA-NL-treated patients compared to those treated with CsA-SM. The use of CsA-NL did not predispose these patients to a higher risk of adverse events.

Adolescent↗
PubMed2001

Increased incidence of acute ascending aortic dissection with off-pump aortocoronary bypass surgery?

BACKGROUND: An apparent increase in the incidence of acute ascending aortic dissection following off-pump coronary artery bypass grafting (OPCAB) led us to assess retrospectively the rate and circumstances of this complication in our institution on a consecutive series of patients undergoing aortocoronary bypass performed with and without extracorporeal circulation (ECC). METHODS: A retrospective analysis of acute ascending aortic dissections complicating coronary artery bypass grafting surgery in 3,031 patients in our institution since April 1, 1995, was performed using the database of the Montreal Heart Institute. RESULTS: There was a greater frequency of hypertension in the OPCAB group. Iatrogenic acute aortic dissection occurred in 3 patients among 308 operated on without ECC (0.97%) and 1 patient among 2,723 operated on under ECC (0.04%). This difference was statistically significant (p < 0.00001). CONCLUSIONS: The risk of aortic dissection may be increased in OPCAB. Careful manipulation of the aorta with a single side-clamping and a control of the arterial pressure should be used to minimize aortic trauma. High-risk patients should undergo CABG without side-clamping of the aorta or CABG with ECC to prevent this redoubtable complication of myocardial revascularization.

Aged↗
PubMed2001

A multicenter, randomized, controlled trial of Celsior for flush and hypothermic storage of cardiac allografts.

BACKGROUND: A multicenter, randomized, controlled, open-label trial was conducted to evaluate the safety and efficacy of Celsior when used for flush and hypothermic storage of donor hearts before transplantation. METHODS: Heart transplant recipients were randomized to one of two treatment groups in which donor hearts were flushed and stored in either Celsior or conventional preservation solution(s) (control). Study subjects were followed for 30 days after transplantation. RESULTS: A total of 131 heart transplant recipients were enrolled (Celsior, n = 64; control, n = 67). The treatment groups were evenly distributed in donor and recipient base line characteristics. Graft loss rate was lower in the Celsior group on day 7 (3% versus 9%) and on day 30 (6% versus 13%), but the difference was not statistically significant based on 95% confidence interval analysis. No significant difference was measured between the Celsior and control groups in 7-day patient survival (97% versus 94%) and the proportion of patients with one or more adverse events (Celsior, 88%; control 87%) or serious adverse events (Celsior, 38%; control, 46%). Significantly fewer patients in the Celsior group developed at least one cardiac-related serious adverse event (13% versus 25%). CONCLUSIONS: Celsior was demonstrated to be as safe and effective as conventional solutions for flush and cold storage of cardiac allografts before transplantation.

Adult↗
PubMed2001

Experience with the 19-mm Carpentier-Edwards pericardial bioprosthesis in the elderly.

BACKGROUND: Valve replacement in small aortic root remains a surgical challenge. The objective of this study was to compare results of the 19-mm bioprosthesis with those of larger prostheses in the elderly. METHODS: The 443 patients, 70 years of age and older, who underwent aortic valve replacement with Carpentier-Edwards pericardial bioprostheses were reviewed. RESULTS: There were 93 patients with a mean age of 76+/-4 years with implantation of 19-mm prostheses and 350 patients with a mean age of 75+/-4 years with larger bioprostheses. Associated aortoplasty was performed in 10 patients (11%) with 19-mm bioprostheses and in 8 patients (2%) with larger bioprostheses (p = 0.001). There were 11 deaths (12%) within 30 days of surgery in patients with 19-mm prostheses and 22 deaths (6%) among those with larger prostheses (p = 0.1). The 7-year survival rate averaged 61%+/-7% in patients with 19-mm prostheses and 67%+/-4% in those with larger prostheses (p = 0.8). The 7-year freedom rates from all valve-related events averaged 96%+/-2% and 93%+/-2%, respectively (p = 0.6). CONCLUSIONS: Aortic valve replacement with the 19-mm Carpentier-Edwards pericardial bioprosthesis offers excellent midterm results in the elderly.

Actuarial Analysis↗
PubMed2001

Aortic valve replacement with mechanical and biologic prosthesis in middle-aged patients.

BACKGROUND: Mechanical prostheses are used in young patients and bioprostheses in the elderly because of the higher rate of structural failure of bioprostheses. The objective of the present study was to compare results after aortic valve replacement with mechanical (Carbo-Medics) and biologic (Carpentier-Edwards pericardial) in middle-aged patients. METHODS: Five hundred twenty-one patients, aged between 55 and 65 years, who underwent aortic valve replacement with mechanical (n = 363) or biologic (n = 158) prostheses were reviewed. RESULTS: The 10-year actuarial survival rate averaged 66%+/-6% in patients implanted with mechanical valves compared with 75%+/-4% in patients implanted with biologic valves (p = 0.2). The 10-year freedom rate from thromboembolism, hemorrhage, and endocarditis averaged 92%+/-7%, 97%+/-2%, and 99%+/-1%, respectively, in patients with mechanical valves compared with 91%+/-3% (p = 0.03), 99%+/-1% (p = 0.4), and 95%+/-2% (p = 0.01), respectively, in those with biologic valves. The 10-year freedom rate from all valve-related complications averaged 90%+/-7% and 83%+/-4%, respectively (p = 0.01). CONCLUSIONS: The freedom rate from all valve-related complications was higher among patients with mechanical valves compared with biologic valves 10 years after aortic valve replacement in middle-aged patients.

Actuarial Analysis↗
PubMed2001

Sternal wound infection after heart transplantation: incidence and results with aggressive surgical treatment.

BACKGROUND: Sternal wound infection remains a significant complication. We reviewed the incidence and the treatment of sternal wound infection after heart transplantation. METHODS: Of 226 patients who had a heart transplantation, 20 (8.8%) underwent postoperative wound debridement for superficial or deep sternal wound infection. The incidence and the survival of patients with sternal wound infection were analyzed. RESULTS: The incidence of sternal wound infection was similar among patients treated with four protocols of immunosuppressive drugs: cyclosporine and prednisone (0 of 22; 0%); cyclosporine, prednisone, and azathioprine (2 of 24; 8.3%); cyclosporine, prednisone, azathioprine, and antithymocyte globulin (15 of 139; 10.8%); and cyclosporine, prednisone, mycophenolate mofetil, and antithymocyte globulin (3 of 41; 7.3%) (p = 0.4). Six-month and 5-year survival of patients with sternal wound infection averaged 85% +/- 8% and 74% +/- 10% compared with 92% +/- 2% and 82% +/- 3% in patients without wound infection (p = 0.15). Patients with deep sternal wound infection, debridement, and reconstruction had a 5-year survival averaging 80% +/- 10%. CONCLUSIONS: The incidence of sternal wound infection remains similar between patients treated with the triple drug therapy. Surgical debridement and reconstruction can result in long-term survival after heart transplantation.

Acute Disease↗
PubMed2001

Arterial balloon catheter: a new atraumatic device for dilating arterial grafts.

BACKGROUND: Harvesting of the internal mammary artery (IMA) for use in myocardial revascularization may result in spasm, which can impair early graft flow. Hydrostatic and mechanical dilatation can exert an intraluminal shear force, causing denudation of the IMA endothelium. A new long balloon dilatation technique (LB) has been developed to mechanically increase IMA diameter and flow without exerting any shear force on the endothelium. METHODS: Vascular rings of porcine IMA were divided into four groups: no manipulation (control), metal dilators (MD), short balloon (SB), or LB intraluminal dilation. In situ flows after dilation and percentage of intact endothelium after silver nitrate staining were determined. Endothelium-dependent contractions with arachidonic acid, relaxations with acetylcholine, endothelium-independent contractions with norepinephrine, and relaxation with sodium nitroprusside were recorded in organ chamber experiments. RESULTS: Increases in IMA flows were similar in all dilated groups. Endothelium-independent contractions and relaxations of IMA smooth muscle were unaffected by any type of mechanical dilation. However, endothelium-dependent contractions and relaxations were significantly impaired after MD and SB but preserved after LB dilation compared with control. Silver nitrate staining showed a greater preservation of the endothelial coverage after LB dilation. CONCLUSIONS: IMA dilatation with the novel arterial LB catheter increases IMA flow and preserves endothelial cell integrity, making it an effective and atraumatic method to relieve IMA spasm before use for coronary artery bypass grafting.

Acetylcholine↗
PubMed2001

Improved preservation of coronary endothelial function with Celsior compared with blood and crystalloid solutions in heart transplantation.

BACKGROUND: Endothelial injury from preservation solutions has been implicated in acute coronary vasospasm and pathologic activation of the endothelium, which can contribute to the development of graft coronary vasculopathy after heart transplantation. Preservation solutions with a powerful antioxidant capacity may decrease the occurrence of these complications. MATERIALS AND METHODS: This study was designed to evaluate the effect of Celsior (an anti-oxidant solution specifically designed for cardiac preservation) in a model of heart preservation (4 hours at 4 degrees C to reproduce the situation encountered in clinical heart transplantation) compared two commonly used cardioplegic and preservation strategies on coronary endothelial function. Endothelium-dependent relaxation of normal porcine epicardial coronary arteries to serotonin (5-HT, an agonist that activates 5-HT(1d) receptors coupled to Gi proteins) and bradykinin (BK, which activates B2 receptors coupled to Gq proteins) was studied in standard organ chamber experiments in the following groups: a control group was submitted to immediate excision without cardioplegia and preserved in saline solution (0.9% NaCl) for 4 hours (Group 1); two groups had cardioplegia induced with a crystalloid solution and were stored for 4 hours in saline (Group 2) or 4 hours in Celsior solution (Group 3); and two groups had cardioplegia induced with normothermic blood cardioplegia and were stored for 4 hours in the saline (Group 4), or 4 hours in Celsior solution (Group 5). Finally, two groups underwent cardioplegia with Celsior and were stored for 4 hours in saline (Group 6), or 4 hours in the Celsior solution (Group 7). All cardioplegia solutions were at 4 degrees C (except blood cardioplegia at 37 degrees C) and all preservations solutions were at 4 degrees C. RESULTS: Endothelium-dependent relaxations to serotonin were significantly decreased in all groups except the Celsior + Celsior group compared with the control group. There were no significant differences in relaxation to bradykinin except in one group. Use of the Celsior solution for induction of cardioplegia and storage better preserved endothelium-dependent G-protein-mediated relaxation compared with the other arrest and preservation strategies. CONCLUSIONS: The observed effect may be associated with an improvement in both short- and long-term outcome in heart transplantation, especially because these alterations may be further compounded by reperfusion.

Animals↗
PubMed2001

Pulmonary metabolism of endothelin 1 during on-pump and beating heart coronary artery bypass operations.

BACKGROUND: Coronary artery bypass operations are associated with increased circulating levels of the powerful vasoconstrictor endothelin 1. The pulmonary circulation is an important site for both production and clearance of endothelin 1. Lung endothelial injury resulting from cardiopulmonary bypass could modify pulmonary endothelin 1 metabolism through an increase in production, a reduction in removal, or a combination of both. METHODS: Pulmonary endothelin 1 kinetics were quantified by using the indicator-dilution technique in patients undergoing coronary artery bypass grafting with (n = 11) or without cardiopulmonary bypass (ie, beating heart; n = 10). Mixed venous endothelin 1 levels were also measured in samples from the pulmonary artery, and systemic levels were obtained from the radial artery. RESULTS: Pulmonary artery endothelin 1 levels were similar before and after cardiopulmonary bypass, with means of 1.59 +/- 0.37 pg/mL and 1.33 +/- 0.15 pg/mL (P =.45), respectively. Systemic endothelin 1 levels, however, increased after bypass from 1.64 +/- 0.22 pg/mL to 2.07 +/- 0.16 pg/mL (P =.01). In the beating heart group, endothelin 1 levels before and after the operation were similar in the pulmonary artery (1.25 +/- 0.27 pg/mL and 1.45 +/- 0.31 pg/mL, respectively; P =.38), as well as in the radial artery (1.70 +/- 0.26 pg/mL and 1.73 +/- 0.35 pg/mL, respectively; P =.92). The capacity to clear endothelin 1 from the pulmonary circulation, as computed from the permeability-surface area product for endothelin 1, was not affected by cardiopulmonary bypass before and after the operation (25.19 +/- 2.67 mL/s and 23.12 +/- 4.39 mL/s, respectively; P =.49). It was similar and also unaffected in the beating heart group. CONCLUSION: Coronary artery bypass grafting with cardiopulmonary bypass is associated with an increase in systemic endothelin 1 levels. The mechanism involved is not related to a decreased pulmonary clearance of endothelin 1 from the systemic circulation but rather to an increased endothelin 1 release by the lungs.

Aged↗
PubMed2001

Results following valve replacement for ischemic mitral regurgitation.

BACKGROUND: Although several authors have favoured mitral repair in ischemic mitral regurgitation (IMR), mitral valve replacement is a valuable option and most often a necessity in patients with structural IMR. OBJECTIVE: To review the authors' experience with valve replacement for patients with acute and chronic IMR. The effect of preserving the valve leaflets and the subvalvular apparatus during replacement was also evaluated. PATIENTS AND METHODS: The authors' experience with mitral valve replacement for IMR between 1990 and 1999 was retrospectively analyzed at the Montreal Heart Institute, Montreal, Quebec. Results obtained with mitral valve replacement due to degenerative disease were used for comparative purposes. RESULTS: Ninety-two patients with IMR and 213 patients with degenerative mitral regurgitation underwent valve replacement with mechanical prostheses (262 of 305 [86%]) or biological prostheses (43 of 305 [14%]). Fifteen patients (15 of 92 [16%]) died within 30 days of mitral valve replacement among IMR patients compared with eight (eight of 213 [4%)] among patients with degenerative mitral valve disease (P=0.01). The seven-year survival average following mitral valve replacement was 66+/-7% in patients with ischemic disease compared with 72+/-4% in patients with degenerative disease (P=0.07). Cardiopulmonary bypass time (odds ratio [OR] 1.01) and emergency operation (OR 2.5) were correlated with the 30-day mortality; the patient's age (OR 1.04) was the only risk factor correlated with the seven-year mortality after valve replacement. The five-year survival of patients with papillary muscle rupture averaged 59+/-12% compared with 78+/-7% in those with functional IMR. CONCLUSIONS: Preoperative risk factors and higher early mortality in patients with mitral valve replacement for ischemic disease contribute to a lower seven-year survival than with mitral valve surgery for degenerative disease. The short and long term survival of the patients in the acute structural mitral disease subgroup was significantly worse.

Aged↗
PubMed2001

Predictive value of Candida colonization index in 131 patients undergoing two different cardiovascular surgical procedures.

BACKGROUND: Nosocomial candidemia is an important infection because of its increasing incidence and its high fatality rate. Candidiasis involves multiple risk factors. In this work, we study the degree of Candida colonization in cardiovascular surgical patients by taking into account the number of sites colonized and the density of growth. METHODS: Eleven (11) selected variables (age, sex, weight, diabetes, number of antibiotics, duration of antibiotics, length of hospitalization, length of stay in surgical intensive care unit, duration of surgery, temperature during surgery, and number of bypass) were considered to predict the perioperative variation of the colonization index (CI) by Candida in 131 cardiovascular surgical patients. These patients were divided into two groups: group A, coronary artery bypass grafting with extracorporeal circulation (72 patients) and group B, coronary artery bypass grafting without extracorporeal circulation (59 patients). RESULTS: One thousand and forty-eight fungal cultures were obtained from four different body sites and 162 isolated were identified. Candida albicans accounted for 74% of the strains in group A and 97% in group B. The statistical analysis (two-way anova) shows that group A patients with an increased CI have received significantly more antibiotics than those with a stable CI (1.50+/-0.83 vs 1.08+/- 0.40, p=0.0055). CONCLUSIONS: Epidemiological data obtained from this study show that coronary artery bypass grafting with extracorporeal circulation procedure is associated with an increase in the use of antibiotics and subsequently a higher risk a Candida colonization-infection.

Aged↗
PubMed2001

Chronic effects of arterial balloon dilatation on internal mammary artery endothelial function.

BACKGROUND: Manipulation for harvesting of the internal mammary artery (IMA) for coronary artery bypass grafting has been shown to acutely impair endothelium-dependent, but not endothelium-independent contractions and relaxations. Recently the use of a novel arterial balloon catheter to dilate the IMA has shown an increased IMA flow while preserving endothelial cell integrity and function acutely. This study examines the chronic effects on endothelial function of IMA segments subjected to arterial balloon catheter dilatation in comparison to either no manipulation (control), luminal dilatation with papaverine, or temporary occlusion with soft or hard jaw in a porcine model. METHODS: Porcine IMAs were harvested one month after instrumentation. Ten IMA segments in each group were obtained and placed in organ chambers under isometric tension. Maximal endothelium-dependent contractions with arachidonic acid and relaxations with acetylcholine, and endothelium-independent contractions with norepinephrine and relaxations with sodium nitroprusside were measured. RESULTS: Endothelium-dependent contractions and relaxations were significantly impaired after hard jaw occlusion one month after IMA manipulation compared to control, long balloon, fibrous jaw, and papaverine groups. Endothelium-independent contractions and relaxations of IMA smooth muscle were unaffected at one month after manipulation. CONCLUSION: We conclude that arterial long balloon dilatation is not detrimental to endothelial cell function chronically and is therefore an effective and atraumatic method to relieve IMA spasm before coronary bypass grafting.

Animals↗
PubMed2000

Torsades de pointes secondary to intravenous haloperidol after coronary bypass grafting surgery.

PURPOSE: Postoperative delirium occurs in about 2% of patients undergoing major cardiac surgery including coronary artery bypass grafting surgery (CABG). Haloperidol (Sabex, Boucherville, Canada) is a drug commonly used in the intensive care unit for the treatment of delirium and is usually considered safe even at high doses and is rarely implicated in the development of malignant ventricular arrhythmias such as torsades de pointes. The purpose of this study is to report such a complication of use of haloperidol after myocardial revascularization. CLINICAL FEATURES: The patient reported underwent uneventful triple bypass surgery. Administration of large intravenous doses of haloperidol was necessary for control of psychomotor agitation due to delirium. Torsades de pointes occurred in the absence of QT prolongation on the third postoperative day following use of the drug with no other obvious etiological factor. CONCLUSION: Awareness of this rare complication is key to judicious use of this drug in the post CABG patient in whom such an arrhythmia may have very deleterious consequences because of the underlying cardiac condition.

Anti-Dyskinesia Agents↗