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Biomedical subjects

André Y Denault

Publications and source records attributed to André Y Denault.

At least 19 recordsLinked to original sources
PubMed2007

Implantation of the CoreValve percutaneous aortic valve.

Surgical aortic valve replacement is the only recommended treatment for significant aortic valve stenosis. Percutaneous aortic valve replacement appears to be a novel option for high-risk patients. We report the implantation of the ReValving system (CoreValve, Paris, France) in a 64-year-old woman who was refused aortic valve replacement surgery for critical aortic stenosis and left ventricular dysfunction because of severe pulmonary fibrosis. After anesthesia, the patient was put on femorofemoral cardiopulmonary bypass, and underwent a balloon valvuloplasty with subsequent retrograde aortic valve replacement by the ReValving system. Transesophageal echocardiographic monitoring of the patient's hemodynamics showed immediate improvements of the valvular area and left ventricular ejection fraction and only traces of paravalvular leaks. The patient was easily weaned from ventilation and resumed activity soon after the surgery. A multidisciplinary approach is presently necessary to offer a reliable and safe procedure.

Aortic Valve Stenosis↗
PubMed2006

Importance of relative pulmonary hypertension in cardiac surgery: the mean systemic-to-pulmonary artery pressure ratio.

OBJECTIVE: To determine the importance of the mean arterial pressure-to-mean pulmonary artery pressure ratio (MAP/MPAP) in cardiac surgical patients. DESIGN: Retrospective and prospective studies (3 groups). SETTING: Tertiary care hospital. PARTICIPANTS: Cardiac surgical patients (1,557). INTERVENTION: Retrospective analysis (group 1), induction of general anesthesia (group 2), and transesophageal Doppler echocardiography (group 3). MEASUREMENTS AND MAIN RESULTS: In group 1 (n = 1,439), demographic, hemodynamic, and other perioperative variables were collected with follow-up until hospital discharge. The primary outcome was a composite index of hemodynamic complications that included death, resuscitated cardiac arrest, use of vasopressive drugs for >24 hours postoperatively, or the use of an intra-aortic balloon pump that was not present preoperatively. In group 2 (n = 34), the effect of general anesthesia on the MAP/MPAP ratio was studied, and Doppler echocardiography was used to evaluate diastolic profiles in group 3 (n = 74). In group 1, a total of 302 patients experienced hemodynamic complications (21%). The MAP/MPAP ratio was significantly lower in the patients who developed complications (3.3 +/- 1.3 v 4.0 +/- 1.4, p < 0.0001). Multiple stepwise logistic regression analysis showed the MAP/MPAP ratio to be an independent predictor of hemodynamic complications (p < 0.0001). In group 2, the induction of anesthesia decreased both MAP and MPAP, but the ratio remain unchanged (p = 0.242). In group 3, patients with moderate-to-severe diastolic dysfunction (DD) had a lower ratio (3.5 +/- 0.9 v 4.0 +/- 1.1 compared with those with normal-to-mild DD, p = 0.07). CONCLUSION: The MAP/MPAP ratio is a useful hemodynamic variable in cardiac surgery. It can be used to predict hemodynamic complications after cardiac surgery, is not influenced by the induction of anesthesia, and tends to correlate with the severity of left ventricular diastolic profiles.

Aged↗
PubMed2006

Left and right ventricular diastolic dysfunction as predictors of difficult separation from cardiopulmonary bypass.

PURPOSE: As the evaluation of diastolic function can be complex in the setting of a busy cardiac operating room, its assessment may benefit from an algorithmic approach using transesophageal echocardiography. We developed a diagnostic algorithm which was then applied in a series of cardiac surgery patients to determine whether moderate to severe left ventricular diastolic dysfunction (LVDD) and right ventricular diastolic dysfunction (RVDD) can predict difficult separation from cardiopulmonary bypass (DSB). METHODS: An algorithm using pulsed-wave Doppler interrogation of the mitral and tricuspid valve, the pulmonary and hepatic venous flow, and tissue Doppler interrogation of the mitral and tricuspid annulus was developed. The study was divided in two phases involving two groups of patients undergoing cardiac surgery. In phase I, echocardiographic evaluations of patients (n = 74) were used to test the reproducibility of the algorithm and to evaluate inter-observer variability using Cohen's kappa values which were calculated in three specific periods. In phase II, the algorithm was applied to a second group of patients (validation group, n = 179) to explore its prognostic significance. The primary end-point in phase II was DSB. RESULTS: In phase I, the kappa coefficients for LVDD and RVDD algorithms were 0.77 and 0.82, respectively. In phase II, moderate or severe degrees of LVDD were observed in 29 patients (16%) and moderate to severe RVDD was observed in 18 patients (10%) before cardiac surgery. Both moderate and severe LVDD (P = 0.017) and RVDD (P = 0.049) before surgery were observed more frequently in patients with DSB. CONCLUSION: Moderate and severe LVDD and RVDD can be identified with very good reproducibility, and both degrees of diastolic dysfunction are associated with DSB.

Aged↗
PubMed2006

Dynamic quantitative echocardiographic evaluation of mitral regurgitation in the operating department.

Hemodynamic modifications induced by general anesthesia could lead to underestimation of mitral regurgitation (MR) severity in the operating department and potentially serious consequences. The intraoperative severity of MR was prospectively compared with the preoperative baseline evaluation using dynamic quantitative transesophageal echocardiography in 25 patients who were stable with MR 2/4 or greater undergoing coronary bypass, mitral valve operation, or both. Significant changes in the severity of MR using transesophageal echocardiographic criteria occurred after the induction of general anesthesia and with phenylephrine. Quantitative transesophageal echocardiographic evaluation of MR using effective orifice area and vena contracta, and the use of phenylephrine challenge, were useful to avoid underestimating MR severity in the operating department.

Adolescent↗
PubMed2006

Biventricular diastolic filling patterns after coronary artery bypass graft surgery.

OBJECTIVE: We sought to study the evolution of biventricular filling properties after coronary artery bypass grafting. BACKGROUND: The evolution of diastolic function as defined with newer echocardiographic modalities after coronary artery bypass grafting surgery is unknown in patients with preoperative left ventricular diastolic dysfunction. METHODS: Transthoracic echocardiography was performed preoperatively and 48 hours and 6 months after coronary artery bypass grafting in 49 patients (randomized to milrinone [n = 25]) or placebo [n = 24]) with preoperative left ventricular diastolic dysfunction classified according to published criteria. Mild right ventricular diastolic dysfunction was defined as the ratio of early to atrial filling velocity of less than 1 in transtricuspid flow or the velocity of reversed atrial flow of greater than 50% of that of systolic flow in hepatic venous flow or the ratio of tricuspid annulus velocity during early and atrial filling of less than 1 if both the ratio of early to atrial filling velocity and the ratio of systolic to diastolic velocity was greater than 1 in hepatic venous flow. Moderate right ventricular diastolic dysfunction was diagnosed when there was a ratio of early to atrial filling velocity of greater than 1 with a ratio of systolic to diastolic velocity of less than 1. Severe right ventricular diastolic dysfunction was defined as a ratio of early to atrial filling velocity of greater than 1 associated with reversed systolic wave in hepatic venous flow. RESULTS: Moderate and severe left ventricular diastolic dysfunction increased from preoperatively to 48 hours after coronary artery bypass grafting from 8.2% to 53.7% and from 2.0% to 9.7%, respectively (P < .0001, 48 hours vs preoperatively for both), and the patterns at 6 months were similar to those observed preoperatively. Similar evolution over time was found for right ventricular diastolic dysfunction. CONCLUSIONS: In patients with preoperative left ventricular diastolic dysfunction, biventricular filling patterns are impaired initially but return to preoperative status 6 months after coronary artery bypass grafting.

Aged↗
PubMed2006

Dynamic right ventricular outflow tract obstruction in cardiac surgery.

BACKGROUND: Right ventricular outflow tract obstruction can be a cause of hemodynamic instability but it has not been described in non-congenital cardiac surgery. METHODS: The prevalence of right ventricular outflow tract obstruction was retrospectively studied in 670 consecutive patients undergoing cardiac surgery. Significant right ventricular outflow tract obstruction was diagnosed if the right ventricular systolic to pulmonary artery peak gradient was more than 25 mm Hg. The diagnosis was based on measurement of the right ventricular and pulmonary artery systolic pressure through the paceport and distal opening of the pulmonary artery catheter. To further validate the prevalence and the importance of right ventricular outflow tract obstruction, 130 patients were prospectively studied over a 12-month period. RESULTS: In the retrospective cohort, 6 patients (1%) undergoing various types of cardiac surgical procedures were found to have significant dynamic right ventricular outflow tract obstruction with a mean gradient of 31 +/- 4 mm Hg (26 to 35 mm Hg). In the prospective study significant dynamic right ventricular outflow tract obstruction was identified in 5 patients (4%) (average peak: 37 +/- 15 mm Hg; range: 27 to 60 mm Hg). The typical transesophageal echocardiography finding was end-systolic obliteration of the right ventricular outflow tract. In patients with significant dynamic right ventricular outflow tract obstruction, hemodynamic instability was present in 10/11 patients (91%). CONCLUSIONS: Right ventricular outflow tract obstruction is easily diagnosed using the paceport of the pulmonary artery catheter and should be considered as a potential cause of hemodynamic instability especially when transesophageal echocardiography reveals systolic right ventricular cavity obliteration.

Aged↗
PubMed2006

Inhaled milrinone: a new alternative in cardiac surgery?

The administration of milrinone through inhalation has been studied in only a few animal and human studies. Compared to the intravenous administration, inhaled milrinone has been shown to reduce pulmonary artery pressure without systemic hypotension. Therefore, this approach could represent an alternative to nitric oxide. This current state of knowledge of intravenous and inhaled milrinone is presented and summarized.

Administration, Inhalation↗
PubMed2006

Erythropoietic response to two epoetin alfa regimens in critically ill patients: a pilot study.

STUDY OBJECTIVE: To compare the erythropoietic responses and tolerability of two recombinant human erythropoietin (EPO) regimens. DESIGN: Prospective, open-label, multicenter study. SETTING: Three multidisciplinary intensive care units in Québec, Canada. PATIENTS: Sixty critically ill patients. INTERVENTION: The first 30 patients received EPO 40,000 U/week (group A); the next 30 received 40,000 U twice/week (group B). MEASUREMENTS AND MAIN RESULTS: Percent change from baseline in reticulocyte count and hemoglobin concentration were evaluated in both groups on study days 7 and 14. The numbers of adverse events were also compared between the two groups. No statistically significant differences were found in the results between the two groups. CONCLUSION: Although the study had limitations, it suggested that EPO 40,000 U twice/week did not increase or sustain stimulation of the erythropoietic response compared with EPO 40,000 U/week in critically ill patients.

Aged↗
PubMed2005

Cerebral near-infrared spectroscopy in adult heart surgery: systematic review of its clinical efficacy.

PURPOSE: This systematic review is aimed at answering the following questions: 1) Is near-infrared spectroscopy (NIRS) clinically effective in detecting cerebral desaturation during heart surgery? 2) Are these results based on studies with solid methodology? SOURCES: MEDLINE, internet, and hand searches up to February 2004 for English and French papers on NIRS. PRINCIPAL FINDINGS: Forty-eight papers were retrieved, with a total of 5,931 cardiac surgery patients monitored by NIRS. More than 83% of patients underwent coronary artery bypass graft surgery. The majority of studies were prospective for the monitored group. Clinically, NIRS monitoring appears to detect brain desaturation episodes encountered during surgery. However, the majority of studies retrieved suffered from major methodological limitations and a low level of evidence. NIRS validity vs jugular bulb oximetry is questioned together with its predictive value in identifying those who will suffer postoperatively from neurological deficits. The sole randomized controlled trial appears to have recorded negative results in this respect. CONCLUSION: The clinical application of NIRS in heart surgery as a brain-monitoring device seems interesting. However, NIRS has to be investigated more rigorously to prove its clinical utility in cardiac surgery.

Adult↗
PubMed2005

Incidence and significance of abnormal hepatic venous Doppler flow velocities before cardiac surgery.

OBJECTIVE: The purpose of this study was to determine the incidence and significance of abnormal hepatic Doppler venous flow velocities as signs of an abnormal right ventricular filling pattern before cardiac surgery. DESIGN: Retrospective and prospective validation study. SETTING: Tertiary care hospital. PARTICIPANTS: Cardiac surgical patients (121 patients). INTERVENTIONS: Not applicable. MEASUREMENTS: Demographic, hemodynamic, and echocardiographic variables; vasoactive support; and difficult separation from bypass were compared between patients with or without abnormal hepatic venous Doppler flow. Logistic regression analysis was performed to identify predictors of difficult separation from bypass. Abnormal hepatic venous flow was observed in 23 (29%) and 17 patients (41%) in the retrospective and prospective study. Abnormal hepatic venous flow before surgery was associated with more vasoactive support in both the retrospective (p = 0.0362) and prospective study (p = 0.0163). In the prospective study, abnormal hepatic venous flow was associated with a higher Parsonnet score (p = 0.0005), more atrial fibrillation (p < 0.0001), pacemaker requirement (p = 0.0124), mitral valve replacement (p = 0.0325), reoperation (p = 0.0050), lower mean arterial pressure to pulmonary artery pressure ratio (p = 0.0127), higher wall motion score index (p = 0.0491), and higher incidence of abnormal right ventricular systolic function (p = 0.0139). Abnormal hepatic venous flow was not found to be an independent predictor of difficult separation from bypass. CONCLUSIONS: Abnormal hepatic venous flow velocities before cardiac surgery are frequent and are associated with increased need for vasoactive support after cardiopulmonary bypass. However, it is not an independent predictor of difficult separation from bypass and worse outcome.

Aged↗
PubMed2004

Bench-to-bedside review: iron metabolism in critically ill patients.

Critically ill patients frequently develop anemia due to several factors. Iron-withholding mechanisms caused by inflammation contribute to this anemia. The iron metabolism imbalances described or reported in all intensive care studies are similar to the values observed in anemia of inflammation. The administration of iron could be useful in the optimization of recombinant human erythropoietin activity, but this could be at the expense of bacterial proliferation. Since there is a lack of evidence to support either oral or intravenous iron administration in intensive care patients, further studies are necessary to determine the efficacy and safety of iron supplementation in conjunction with recombinant human erythropoietin in critically ill patients. We review the mechanisms leading to iron sequestration in the presence of inflammation. The present article also reviews the literature describing the iron status in critically ill patients and explores the role of iron supplementation in this setting.

Anemia↗
PubMed2004

Vasopressin for treatment of shock following aprotinin administration.

PURPOSE: To describe the utility of vasopressin in the treatment of acute distributive shock clinically compatible with the diagnosis of aprotinin anaphylaxis. CLINICAL FEATURES: A 57-yr-old female patient underwent repeat cardiac surgery to treat prosthetic valve endocarditis. She had received aprotinin during her first surgery 60 days ago. Despite a negative test dose of i.v. aprotinin 20,000 KIU, when aprotinin loading was initiated during the repeat surgery, the patient developed bronchospasm and hypotension secondary to acute distributive shock. Bronchospasm responded to inhaled salbutamol and ipatropium. The hypotension was refractory to high doses of phenylephrine. Two doses of i.v. vasopressin 5 U reversed the vasodilation and reestablished normal blood pressure. CONCLUSION: Vasopressin, in association with alpha-agonists, can reverse acute refractory distributive shock following aprotinin administration.

Aprotinin↗
PubMed2003

Can peripheral venous pressure be interchangeable with central venous pressure in patients undergoing cardiac surgery?

OBJECTIVE: Pressure measurements at the level of the right atrium are commonly used in clinical anesthesia and the intensive care unit (ICU). There is growing interest in the use of peripheral venous sites for estimating central venous pressure (CVP). This study compared bias, precision, and covariance in simultaneous measurements of CVP and of peripheral venous pressure (PVP) in patients with various hemodynamic conditions. DESIGN AND SETTING: Operating room and ICU of a tertiary care university-affiliated hospital. PATIENTS: Nineteen elective cardiac surgery patients requiring cardiopulmonary bypass were studied. INTERVENTIONS: A PVP catheter was placed in the antecubital vein and connected to the transducer of the pulmonary artery catheter with a T connector. Data were acquired at different times during cardiac surgery and in the ICU. MEASUREMENTS AND RESULTS: A total of 188 measurements in 19 patients were obtained under various hemodynamic conditions which included before and after the introduction of mechanical ventilation, following the induction of anesthesia, fluid infusion, application of positive end expiratory pressure and administration of nitroglycerin. PVP and CVP values were correlated and were interchangeable, with a bias of the PVP between -0.72 and 0 mmHg compared to the CVP. CONCLUSIONS: PVP monitoring can accurately estimate CVP under various conditions encountered in the operating room and in the ICU.

Aged↗
PubMed2003

Magnesium potentiates neuromuscular blockade with cisatracurium during cardiac surgery.

PURPOSE: Magnesium potentiates the effect of nondepolarizing neuromuscular blocking agents. It is used in cardiac anesthesia to prevent hypertension and arrhythmias. This study was performed to measure the interaction between magnesium and cisatracurium in cardiac surgery. METHODS: Twenty patients scheduled for elective cardiac surgery were randomly assigned to receive magnesium sulfate (70 mg x kg(-1) at induction followed by 30 mg x kg(-1) x hr(-1)) or placebo. The ulnar nerve was stimulated and the electromyographic response of the adductor pollicis was measured. Cisatracurium 0.1 mg x kg(-1) was given at induction, followed by 0.05 mg x kg(-1) when the first twitch in the train-of-four reached 25%. RESULTS: Ionized magnesium was 1.32 +/- 0.24 mmol x L(-1) in the treatment group vs 0.47 +/- 0.4 mmol x L(-1) in the control group. Duration of action of the intubating dose was longer in the magnesium group (74 +/- 20 min) than in the placebo group (42 +/- 6 min, P = 0.0001). Duration of the first maintenance dose was 69 +/- 16 min in the magnesium group vs 35 +/- 7 min in the placebo group (P = 0.0001). Total dose of cisatracurium administered throughout surgery was 0.19 +/- 0.07 mg x kg(-1) in the magnesium group compared with 0.29 +/- 0.01 mg x kg(-1) in the placebo group (P = 0.017). Hemodynamic variables and temperature were similar in both groups. CONCLUSION: In patients undergoing cardiac surgery, administration of magnesium sulfate, resulting in ionized levels of 1.3 mmol x L(-1), results in a 30-35 min prolongation of the neuromuscular blockade induced with intubating and maintenance doses of cisatracurium and does not alter hemodynamic stability.

Aged↗
PubMed2003

Partial inferior vena cava snaring to control ischemic left ventricular dysfunction.

PURPOSE: To describe the hemodynamic and intraoperative transesophageal echocardiographic evaluation of cardiac systolic and diastolic function in a patient undergoing off-pump coronary artery bypass graft (OP-CABG) surgery who developed pulmonary artery hypertension controlled by inferior vena cava (IVC) snaring. CLINICAL FEATURES: A 63-yr-old man was referred to our hospital for elective OP-CABG surgery. His preoperative ventriculopathy revealed a decreased systolic function (ejection fraction of 35%), and a mild mitral regurgitation. Intraoperatively, after application of the stabilizer and clamping of the diagonal artery, he developed a marked increase in pulmonary artery pressure (PAP) with a decrease in systemic arterial pressure, non responsive to iv norepinephrine and nitroglycerin. Transesophageal echocardiographic evaluation revealed a marked decrease in systolic function and presence of a restrictive diastolic filling pattern. Partial IVC snaring decreased the venous return and PAP decreased cardiac chamber dimensions, improved systolic function and improved diastolic filling pattern. CONCLUSION: Partial IVC snaring was used successfully to treat a hemodynamically unstable patient with sudden increase in PAP caused by ischemic left ventricular failure during OP-CABG.

Coronary Artery Bypass↗
PubMed2002

Perioperative use of transesophageal echocardiography by anesthesiologists: impact in noncardiac surgery and in the intensive care unit.

BACKGROUND: The American Society of Anesthesiologists (ASA) has published practice guidelines for the use of perioperative transesophageal echocardiography (TEE) but the role and impact of TEE performed by anesthesiologists outside the cardiac operating room (OR) is still poorly explored. We report our experience in the use of TEE in the noncardiac OR, the recovery room and in the intensive care unit (ICU) in a university hospital, and analyze the impact of TEE on clinical decision making. METHODS: Two hundred fourteen patients were included and TEE indications were classified prospectively according to the ASA guidelines. The examinations and data sheets were reviewed by two anesthesiologists with advanced training in TEE. For each examination, it was noted if TEE altered the management according to five groups: 1) changing medical therapy; 2) changing surgical therapy; 3) confirmation of a diagnosis; 4) positioning of an intravascular device; and 5) TEE used as a substitute to a pulmonary artery catheter. RESULTS: Eighty-nine (37%), 67 (31%) and 58 (27%) patients had category I, II and III indications. The impact was more significant in category I where TEE altered therapy 60% of the time compared with 31% and 21% for categories II and III (P < 0.001). The most frequent reason for changing management was a modification in medical therapy in 53 instances (45%). CONCLUSION: Our results confirm a greater impact of TEE performed by anesthesiologists on clinical management for category I compared to category II and III indications in the noncardiac OR surgical setting and in the ICU.

Anesthesiology↗
PubMed2002

Mitral Doppler indices are superior to two-dimensional echocardiographic and hemodynamic variables in predicting responsiveness of cardiac output to a rapid intravenous infusion of colloid.

UNLABELLED: We hypothesized that mitral flow (MF) Doppler measurements could be used to predict cardiac output (CO) responsiveness to fluid challenge. Fourteen patients with normal systolic and diastolic function, scheduled for coronary artery bypass graft surgery, were evaluated as part of a pilot study in which preload was varied immediately before the beginning of cardiopulmonary bypass. A Validation group of 36 patients with different levels of systolic and diastolic function received a rapid infusion of 500 mL of 10% pentastarch. By use of transesophageal echocardiography, we measured left ventricular end-diastolic area, pulsed Doppler indices of the MF and pulmonary venous flow, and standard hemodynamic variables during acute volemic variations. A baseline measurement was first recorded, followed by measurements taken after a decrease (211 +/- 87 mL) and then an increase (176 +/- 149 mL) in preload (pilot study) and before and after 500 mL of pentastarch (validation study). In the pilot study, we found that a low velocity/time integral (VTI) E wave/A wave (E/A) ratio was associated with a larger increase in CO secondary to an increase in preload (r = 0.64, P < 0.05). Stepwise linear regression identified Doppler measurements of the mitral VTI E/A ratio as the most important variable to predict the increase in CO after fluid infusion. In the validation study, a mitral E/A ratio <1.26 before fluid infusion best predicted a 20% increase in stroke volume (receiver operating characteristic curve, 71%; P < 0.05), whereas no other hemodynamic or echocardiographic variable predicted preload responsiveness. We conclude that the MF Doppler filling pattern is an important factor to predict the increase in CO after intravascular fluid challenge in patients undergoing coronary artery bypass grafting. IMPLICATIONS: In the presence of low cardiac output, the clinician's ability to identify which patients are more likely to benefit from volume administration to improve hemodynamic status while avoiding fluid overload is important. The analysis of Doppler measurement of the mitral flow as an indirect indicator of the individual diastolic pressure/volume relationship may be useful to predict the intravascular volume responsiveness in patients undergoing coronary artery bypass graft surgery.

Adult↗