Biomedical subjects

J Métras

Publications and source records attributed to J Métras.

15 recordsLinked to original sources

PubMed2003

Does moderate mitral regurgitation impact early or mid-term clinical outcome in patients undergoing isolated aortic valve replacement for aortic stenosis?

OBJECTIVE: The early and mid-term impact of functional mitral regurgitation (MR) in patients undergoing isolated aortic valve replacement (AVR) for aortic stenosis remains unresolved. METHOD: Through our institutional databank, using a case-match study, we identified 58 patients with MR grades 0-1 and 58 patients with MR grades 2-3 (patients matched for sex, age, ejection fraction (EF), NYHA, diabetes, and CVA). Data were collected prospectively (mean duration of follow-up: 3.2 +/- 2.4 years). RESULTS: Perioperative morbidity (re-operation for bleeding, low cardiac output, CVA, renal failure) was comparable among groups. Difference in mortality between the two groups was non-significant (7.0 vs. 3.5%, P = 0.67 in groups MR 2-3 vs. 0-1, respectively). At early echocardiographic follow-up, 7/58 patients (12.1%) within group MR grades 0-1 increased their MR to grades 2-3; among which only two remained with MR grades 2-3 at mid-term follow-up. Within MR group 2-3, 18/58 (31.0%) remained with MR grades 2-3 among which 7/18 (38.9%) decreased of at least one grade at follow-up. Eight year actuarial survival was comparable in both groups: MR grades 0-1 = 60.9% vs. MR grades 2-3 = 55.0%; P = 0.1. Actuarial survival of patients with MR grades 2-3 postoperatively was similar to patients with MR grades 0-1 (MR grades 0-1 = 59.0%, MR grades 2-3 = 58.9%, P = NS). CONCLUSIONS: Presence of preoperative moderate functional MR (grades 2-3) in patients undergoing isolated AVR for aortic stenosis regresses in the majority of patients postoperatively and has no significant impact on perioperative morbidity or mortality, nor mid-term survival. Thus, moderate functional MR should be treated conservatively in the majority of patients especially in the elderly subjected to isolated AVR for aortic stenosis.

Aged↗

PubMed2001

Patient-prosthesis mismatch can be predicted at the time of operation.

BACKGROUND: Patient-prosthesis mismatch is a frequent cause of high postoperative gradients in normally functioning prostheses. The objective of this study was to determine whether mismatch can be predicted at the time of operation. METHODS: Indices used to predict mismatch were valve size, indexed internal geometric area, and projected indexed effective orifice area (EOA) calculated at the time of operation, and results were compared with indexed EOA and mean gradients measured by Doppler echocardiography after operation in 396 patients. RESULTS: The sensitivity and specificity of these indices to detect mismatch, defined as a postoperative indexed EOA of 0.85 cm2/m2 or less, were respectively: 35% and 84% for valve size, 46% and 85% for indexed internal geometric area, and 73% and 80% for projected indexed EOA. Projected indexed EOA also correlated best with resting (r = 0.67) and exercise (r = 0.77) postoperative gradients. CONCLUSIONS: The projected indexed EOA calculated at the time of operation accurately predicts mismatch as well as resting and exercise postoperative gradients, whereas valve size and indexed internal geometric area cannot be used for this purpose.

Adult↗

PubMed2001

Medtronic Intact porcine bioprosthesis experience to twelve years.

BACKGROUND: The Medtronic Intact porcine bioprosthesis was further evaluated to determine the influence of zero-pressure glutaraldehyde fixation on structural valve deterioration (SVD). METHODS: From 1986 through 1996, at three Canadian centers, 1,272 patients had 1,296 procedures: 836 aortic valve replacement (AVR), 332 mitral valve replacement (MVR), 14 tricuspid valve replacement, 3 pulmonary valve replacement, and 111 multiple valve replacements. The mean age of the patient population was 67 years (range 9 to 91 years). The total follow-up was 8,011 patient-years (mean 6.2 years). RESULTS: The late mortality (overall) was 4.8% and 6.7% per patient-year for AVR with or without concomitant procedures, respectively; and 4.7% and 10.4% per patient-year for MVR, respectively. There were 51 cases of SVD (AVR 22 of 836; MVR 23 of 332; pulmonary valve replacement 1 of 3; and multiple valve replacement 5 of 111). The actuarial freedom from SVD at 12 years for AVR was 94.3%+/-3.3% for patients aged 61 to 70 years and 97.7%+/-1.1% for those more than 70 years; for MVR actuarial freedom from SVD at 12 years was 93.7%+/-3.9% for patients more than 70 years. The actual freedom at 12 years from SVD for AVR was 92.4%+/-3.1% for patients aged 51 to 60 years, 96.1%+/-2.1% for those 61 to 70 years, and 98.4%+/-0.7% for those older than 70 years; for MVR actual freedom from SVD at 12 years was 89.6%+/-3.2% for patients 61 to 70 years and 96.6%+/-3.4% for those more than 70 years. CONCLUSIONS: The Medtronic Intact porcine bioprosthesis, formulated with tissue preservation at zero-pressure fixation, has encouraging freedom from structural failure.

Adolescent↗

PubMed2001

Medtronic Mosaic porcine bioprosthesis: midterm investigational trial results.

BACKGROUND: The midterm clinical and hemodynamic performance of the Medtronic Mosaic porcine bioprosthesis was evaluated in a regulatory trial. METHODS: In nine Canadian centers, 802 bioprostheses (560 aortic and 242 mitral) were implanted between September 1994 and April 1999 in patients with a mean age of 70 years. RESULTS: Survival for aortic valve replacement at 4 years was 84.4%+/-3.1%. Freedom from valve-related or unexplained death was 95.6%+/-1.9%; structural valve deterioration, 100.0%; reoperation, 96.2%+/-1.7%; major thromboembolism, 96.1%+/-1.8%; and major antithrombotic-related hemorrhage, 96.4%+/-1.7%. Echocardiographic derived mean systolic gradient was 13.4 mm Hg at 4 years with an indexed effective orifice area of 0.7 to 0.8 cm2/m2. A significant decrease in left ventricular mass was shown over time in all valve sizes. Survival for mitral valve replacement at 4 years was 79.2%+/-6.8%. Freedom from valve-related or unexplained death was 96.5%+/-3.4%; structural valve deterioration, 100%; reoperation, 97.0%+/-3.2%; major thromboembolism, 95.7%+/-3.8%; and major antithrombotic-related hemorrhage, 95.0%+/-4.2%. Echocardiographically measured averaged mean diastolic gradient was 4.5 mm Hg. CONCLUSIONS: The Medtronic Mosaic bioprosthesis is safe and effective in both the aortic and mitral positions. The valve has low gradients in both positions and excellent left ventricular mass regression in the patients with aortic valve replacement.

Adult↗

PubMed1999

Clinical and hemodynamic performance of the Freestyle aortic root bioprosthesis.

BACKGROUND: The objective of this study is to assess the clinical and hemodynamic performance of a stentless porcine bioprosthesis, the Freestyle aortic root bioprosthesis. METHODS: Consenting patients requiring isolated aortic valve or aortic root replacement received the Freestyle bioprosthesis. Clinical follow-up and echocardiographic data were obtained at discharge, 3 to 6 months, 1 year, and annually thereafter. RESULTS: Two hundred seventy-six patients received a Freestyle aortic root bioprosthesis between January 1993 and July 1997. The mean age was 67.7 years. Preoperatively, 86.3% were either New York Heart Association class III or IV. Two hundred thirty-eight patients underwent valve (subcoronary) replacement, 36 underwent aortic root replacement, and 2 underwent valve replacement using the root-inclusion technique. The early mortality was 5.4%, with 3.3% mortality for the subcoronary technique and 19.4% mortality for aortic root replacement. The mean gradient decreased significantly between discharge and the 3- to 6-month follow-up and stabilized thereafter. The effective orifice area increased significantly from discharge to 3 to 6 months' follow-up. At 3 years, 84.4% of the patients had either no or trivial regurgitation. CONCLUSIONS: The Freestyle bioprosthesis has good clinical performance and good short-term hemodynamic performance. The majority of the regurgitation identified is not clinically significant.

Adult↗

PubMed1999

Changes in left ventricular mass and function after aortic valve replacement: a comparison between stentless and stented bioprosthetic valves.

The objective of this study was to compare stentless bioprostheses with stented bioprostheses with regard to the postoperative changes in left ventricular (LV) mass and function. Forty patients with aortic stenosis undergoing valve replacement with a stentless (20 patients) or a stented (20 patients) bioprosthesis were evaluated early (baseline), 1 year, and 2 years after operation. Left ventricular mass index was calculated with the corrected American Society of Echocardiography formula. The relative changes between end-diastole and end-systole in LV mid-wall radius, length, and volume (ejection fraction) were determined with a previously validated model for dynamic geometry of the left ventricle. Overall, a significant decrease was found in LV mass index (from 155 +/- 30 to 112 +/- 23 g/m(2); P <.001) and a significant increase in longitudinal shortening (from 0.12 +/- 0.11 to 0.22 +/- 0.08; P <. 001), and ejection fractions (from 0.67 +/- 0.11 to 0.71 +/- 0.10; P =.017). No significant change was found in the mid-wall radius shortening fraction. Two years after surgery, the extent of LV mass regression was greater in stentless bioprostheses (-51 +/- 18 vs -35 +/- 17 g/m(2); P =.01), though the average mass index was similar in both groups (114 +/- 26 vs 110 +/- 20 g/m(2)). Also at 2 years, the longitudinal shortening fraction was greater in patients with a stentless bioprosthesis (0.25 +/- 0.07 vs 0.18 +/- 0.08; P =.03). In conclusion, this study suggests that the superior hemodynamic performance of stentless bioprostheses may have some benefits with regard to LV mass regression and function after aortic valve replacement. The significance of these benefits in terms of prognosis remains to be determined.

Aged↗

PubMed1998

Hemodynamic features of the freestyle aortic bioprosthesis compared with stented bioprosthesis.

BACKGROUND: The Freestyle prosthesis is a new stentless aortic bioprosthesis. Anticipated benefits are improved hemodynamics and increased longevity. METHODS: Doppler echocardiograms were performed early and at 3 to 6 months, 1 year, and 2 years after operation in 157 patients (69 men, 88 women, aged 48 to 85 years) with this prosthesis, and results were compared with hemodynamic data in patients with Intact and Mosaic stented bioprostheses. RESULTS: Distinctive features of the prosthesis compared with stented prostheses are (1) an increase in effective orifice area (+0.15+/-0.26 cm2; p < 0.05) and a decrease in mean gradient (-3.5+/-4.0 mm Hg; p < 0.001) during the first 3 to 6 months postoperatively and stabilization thereafter; (2) a markedly lower mean gradient at 1 year after operation (average, 6+/-4 mm Hg) than in stented prostheses (Intact, 22+/-8 mm Hg; Mosaic, 12+/-6 mm Hg); (3) in contrast to stented prostheses, in vivo effective orifice areas much lower (-0.91+/-0.35 cm2) than those calculated in vitro; (4) as in stented prostheses, the indexed effective orifice area (cm2/m2) is the best predictor (r = 0.77 at 1 year) of the mean gradient after operation; and (5) similar incidence of aortic regurgitation (trivial or mild, 34% versus 29% in Intact). CONCLUSIONS: The hemodynamics of the Freestyle are very satisfactory and represent a marked improvement in comparison to stented prosthesis.

Aged↗

PubMed1998

Medtronic intact porcine bioprosthesis: 10 years' experience.

BACKGROUND: The Medtronic Intact porcine bioprosthesis experience was evaluated over a period of 10 years to determine the influence of structural valve deterioration by valve position in various age groupings. METHODS: From 1986 to 1996 inclusive, at three centers, 1,272 patients had the prosthesis implanted in 1,296 procedures. The mean age of the population was 67 years (range, 9 to 91 years). There were 836 aortic valve replacements (AVR) (64.5%), 333 mitral valve replacements (MVR) (25.7%), and 110 multiple valve replacements (MR) (8.5%). RESULTS: The early mortality was 7.3% (94 of 1,296 procedures). The early mortality with concomitant procedures (primarily coronary artery bypass grafting) was 9.8% (52 of 528) and without, 5.5% (42 of 768). The late mortality was 4.25%/patient-year. The linearized rate of major thromboembolism was 0.86%/patient-year. The rate of reoperation was 1.19%/patient-year and valve-related mortality, 1.06%/patient-year. There were 36 cases of structural valve deterioration for aortic valve replacement (16), mitral valve replacement (15), tricuspid valve replacement (2), and multiple valve replacement (3). The freedom from structural valve deterioration for aortic valve replacement was in patients 21 to 40 years, 62.5%+/-25.8% at 7 years; 41 to 50 years, 75.0%+/-15.3% at 7 years; 51 to 60 years, 91.0%+/-4.5% at 8 years; 61 to 70 years, 98.7%+/-0.7% at 10 years; and older than 70 years, 98.3%+/-1.0% at 10 years (p < 0.05). The freedom from structural valve deterioration for mitral valve replacement was for patients 41 to 50 years, 91.7%+/-8.0% at 7 years; 51 to 60 years, 85.9%+/-9.9% at 8 years; 61 to 70 years, 86.3%+/-6.8% at 8 years; and older than 70 years, 93.9%+/-4.8% at 8 years (not significant). CONCLUSIONS: The Medtronic Intact porcine bioprosthesis has acceptable freedom from structural valve deterioration in both the aortic and mitral positions approaching 10 years of evaluation.

Actuarial Analysis↗

PubMed1998

Medtronic mosaic porcine bioprosthesis satisfactory early clinical performance.

BACKGROUND: The Medtronic (Minneapolis, MN) Mosaic porcine bioprosthesis is an investigational prosthesis which incorporates zero-pressure fixation, aortic root predilation, low profile stent, and alpha oleic acid antimineralization treatment. METHODS: From September 1994 to August 1996, 289 patients (mean age 70 years, range, 28 to 88 years) had 227 (78.5%) aortic valve replacements and 62 (21.5%) mitral valve replacements. Concomitant procedures were performed in 61.2% (139) of aortic valve replacements and 54.8% (34) of mitral valve replacements. Of the aortic valve replacement group 70 (30.8%) were in the 61 to 70 age group and 134 (59.0%) were 71 years or older. Of the mitral valve replacements, 23 (37.1%) were 61 to 70 years and 30 (48.4%) 71 years or older. RESULTS: The early mortality, overall, was 4.2% (12 of 289); for aortic valve replacement it was 4.0% (9) and for mitral valve replacement it was 4.8% (3). The late mortality for aortic valve replacement was 2.6% per patient-year (3 events, 1.3% of total) and for mitral valve replacement it was 3.3% per patient-year (one event, 1.6% of total). The reoperative rate for aortic valve replacement was 3.0% per patient-year (4), while there were no mitral valve replacement reoperations. The freedom from major thromboembolism was 97.3%+/-1.6% for aortic valve replacement and 94.7%+/-3.0% for mitral valve replacement at 1 to 1.5 years. The freedom from reoperation was 96.7%+/-1.7% for aortic valve replacement; there was no reoperation for mitral valve replacement. There were no cases of structural valve deterioration. In the aortic position the mean systolic gradient was low, approximately 11 mm Hg, across all sizes (range 8 to 12 mm Hg at 3 months and 10 to 13 mm Hg at 12 months). In the mitral position the mean diastolic gradient was approximately 5 mm Hg (range, 2 to 6 mm Hg) for all sizes 25 to 31 mm at the early and 1 year follow-up echocardiographic assessment. CONCLUSIONS: The early clinical performance and in vivo hemodynamics are encouraging.

Adult↗

PubMed1998

Impact of prosthesis-patient mismatch on hemodynamic and symptomatic status, morbidity and mortality after aortic valve replacement with a bioprosthetic heart valve.

BACKGROUND AND AIMS OF THE STUDY: Previous studies have shown that the effective orifice area of an aortic prosthetic valve may be too small in relation to the patient's body surface area, resulting in abnormally high gradients. The consequences of this condition, termed prosthesis-patient mismatch, have not been fully studied. The study objective was to determine if the condition has a detrimental effect on symptomatic and hemodynamic status, morbidity and mortality of patients undergoing aortic valve replacement. METHODS: A cohort of 392 patients was prospectively followed for up to seven years after implantation of a Medtronic Intact bioprosthesis. Doppler echocardiography was performed annually in 72 patients. Based on previous studies, presence of mismatch was defined as an indexed valve area < or = 0.85 cm2/m2. RESULTS: Mismatch was associated with less postoperative improvement of NYHA functional class (p < 0.009) independently of other predictors, such as age and preoperative functional class, but had no significant impact on patient survival (mismatch: 75 +/- 4%, no mismatch: 79 +/- 3%; p = 0.59) and valve-related morbidity up to seven years. Cardiac index was similar in patients with and without mismatch up to three years after operation but decreased significantly thereafter only in patients with mismatch (-0.54 +/- 0.32 versus -0.17 +/- 0.49 l/min/m2; p = 0.04). Likewise, the mean transprosthetic gradient, which was higher at one year after operation in patients with mismatch (22 +/- 8 versus 15 +/- 7 mmHg), increased significantly (+6 +/- 6 versus +1 +/- 1 mmHg; p = 0.008) only in this group during follow up. CONCLUSIONS: Patients with mismatch have less symptomatic improvement and worse hemodynamics that continue to deteriorate with time. However, medium-term prognosis (up to seven years) is relatively good. Further studies are necessary to determine the longer-term effects of mismatch on morbidity and mortality.

Aged↗

PubMed1995

Aortic valve replacement with pulmonary autograft in children and adults.

Aortic valve replacement with a conventional prosthesis is still flawed with complications, especially in children and young adults. Complex aortic root enlargement (Konno) is often needed because of small aortic diameter. The poor compliance with anticoagulation by teenagers and the risks associated with this made us look at alternative techniques. From November 1990 to June 1994, 70 patients were considered for pulmonary autografts in our institution; 64 underwent the procedure with one death and one failure to implant. Short-term results are excellent, with minimal gradient in 90% and minimal regurgitation in 96% of the patients. The long-term follow-up, hopefully, will confirm the superiority of this procedure over more conventional replacement.

Adolescent↗

PubMed1995

Medtronic Intact porcine bioprosthesis: clinical performance to seven years.

The clinical performance of the Medtronic Intact porcine bioprosthesis was evaluated in 1,084 patients (mean age 66.4 years, range 9 to 91 years) who had a total of 1,099 implantations between 1985 and 1992, inclusive. There were 709 aortic valve replacements, 297 mitral valve replacements, and 80 multiple valve replacements. Concomitant procedures were performed in 432 (39.3%). The age group distribution (years) was 35 or younger in 20 patients, 36 to 50 in 64, 51 to 64 in 274, 65 to 69 in 225, 70 or older in 500. The total follow-up time was 2,741 patient-years (mean, 2.5 years) and was 97.5% complete. The early mortality rate was 7.1% and late mortality was 3.9% per patient-year. The overall patient survival at 7 years was 70% +/- 3%. The freedom from major thromboembolism was 94% +/- 1% at 7 years (p = not significant for valve positions). The freedom from reoperation at 7 years was 93% +/- 1%; freedom from valve-related mortality was 89% +/- 2%. The freedom from structural valve deterioration at 7 years was 97% +/- 1% (aortic valve replacement 97% +/- 1%; mitral valve replacement 97% +/- 2%). The freedom from structural valve deterioration among age groups was not different for the overall population, aortic valve replacement, or mitral valve replacement. Hemodynamic assessment revealed obstructive properties for aortic valve replacement sizes of 21 and 23 mm and for mitral valve replacement sizes of 25 and 27 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗

PubMed1994

[Pulmonary autograft as aortic valve replacement in children].

The aortic stenosis represents 5% of all congenital cardiac pathology. The conventional treatments often do not give very satisfactory results. Since 1990, as alternative to the traditional aortic valve replacement, we used, in our institution, the Ross procedure (pulmonary autograft). This consists in using the pulmonary valve as an autograft in aortic position to replace the diseased valve. Then, the pulmonary outflow is reconstructed with a cryopreserved homograft. This study includes 15 patients, aged between 16 months and 18 years, treated with this technique since 1990. There has been no mortality. All the patients are alive at the follow-up, and all in NYHA functional class I. No reoperation has been necessary for valvular dysfunction. The post-operative doppler study at aortic level demonstrated those gradients: Mean + SD, 3.8 +/- 8.1 (range 0-23). No regurgitation haemodynamically important has been recorded at aortic level nor in the pulmonary position. Post-operative gradients at pulmonary level were: Mean + SD, 14.6 + 10.6 (range 14-32).

Adolescent↗

PubMed1994

Surgical treatment of left main coronary aneurysm.

Aneurysms of the coronary arteries occur in 0.3% to 4.9% of angiograms. Only 13 cases of left main artery (LMA) aneurysms have been reported. Of these, three were treated by ligation of the aneurysm and coronary revascularization; the others by revascularisation alone. We report the case of a 56 years old man presenting with unstable angina and previous history of myocardial infarction. Coronary angiography confirmed three vessels disease and the presence of an aneurysm of the LMA extending to the proximal part of the left anterior descending artery (LAD). The patient was treated with ligation of the aneurysm and total myocardial revascularization. The clinical and radiological features are reviewed, and the surgical options considered.

Angina, Unstable↗

PubMed1985

Concentrations of fusidic acid, cloxacillin, and cefamandole in sera and atrial appendages of patients undergoing cardiac surgery.

The concentrations of cefamandole, cloxacillin and fusicid acid were measured in the serum and heart tissue of 100 recipients of these drugs before cardiac surgery. During cardiopulmonary bypass, mean (+/- standard deviation) peak concentrations in serum of all patients were 63.0 +/- 34.0 micrograms of cefamandole per ml, 30.8 +/- 17.7 micrograms of cloxacillin per ml, and 32.4 +/- 10.8 micrograms of fusidic acid per ml. Mean (+/- standard deviation) concentrations in atrial appendages taken 1 h (+/- 15 min) after infusion were 21.3 +/- 11.0 micrograms of cefamandole per g, 23.8 +/- 17.3 micrograms of cloxacillin per g, and 10.7 +/- 4.2 micrograms of fusidic acid per g. No cloxacillin could be detected in 5 of 39 heart specimens. Mean tissue-to-serum ratios at 1 h for cefamandole, cloxacillin, and fusidic acid were respectively 0.35, 0.73, and 0.33. Fusidic acid, a drug which is highly effective in vitro against both methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis, was detectable in heart tissue in concentrations which were 12 times higher than the MICs of this agent against these resistant microorganisms.

Adult↗