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Biomedical subjects

Rémi Houël

Publications and source records attributed to Rémi Houël.

8 recordsLinked to original sources
PubMed2004

Platelet activation and aggregation profile in prolonged external ventricular support.

BACKGROUND: Platelet function plays a major role in the understanding of thromboembolic events in prolonged mechanical support. We studied the platelet activation, platelet aggregation profile, and efficacy of aspirin in patients in whom an external ventricular assist device had been implanted. PATIENTS AND METHODS: Fifteen patients were studied prospectively up to 6 weeks after implantation of the same type of ventricular assist device. Platelet function was studied weekly before daily aspirin administration. Aspirin efficacy was tested ex vivo by measuring platelet aggregation triggered by arachidonic acid. Flow cytometry was used to quantify the spontaneous and induced (adenosine diphosphate stimulation) expression of glycoproteins alphaIIbbeta3, Ibalpha, and CD62P on platelet membranes. The plasma levels of von Willebrand factor (von Willebrand factor activity and von Willebrand factor antigen) and fibrinogen were also determined. RESULTS: Six of the 15 patients (26%) maintained an arachidonic acid-induced platelet aggregation despite daily aspirin treatment (250 mg). CD62P values remained increased during a 5-week postoperative period. Spontaneous levels of glycoproteins alphaIIbbeta3 and Ibalpha on platelet membranes remained within a normal range with a preserved reactivity. The plasma levels of fibrinogen and von Willebrand factor remained increased during the entire study period. CONCLUSION: In patients with an implanted external ventricular assist device, the platelet activation profile displays a persistent activation with a preserved reactivity associated with a persistent high inflammatory state and endothelial activation.

Adolescent↗
PubMed2004

Usefulness of routine epicardial pacing wire culture for early prediction of poststernotomy mediastinitis.

Poststernotomy mediastinitis (PSM) is one of the most serious complications of cardiac surgery, and its associated morbidity and mortality demand early recognition for emergency therapy. In this study, we investigated the usefulness of epicardial pacing wire (EPW) cultures for the prediction of PSM. Among 2,200 patients who underwent a cardiac surgical procedure at our hospital between 1 January 1999 and 31 December 2001, 82 (3.7%) had PSM; Staphylococcus aureus was the organism (45.1%) most frequently isolated at the time of surgical debridement. EPWs from 1,607 (73.0%) patients, 73 (4.5%) of whom developed PSM, were cultured. EPW cultures from 466 (29.0%) were positive, most often (74.9%) for coagulase-negative Staphylococci. EPW cultures were truly positive in 26 cases, truly negative in 1,106 cases, falsely positive in 428 cases, and falsely negative in 47 cases (with sterile cultures in 35 cases and a culture positive for an organism different from that isolated at the time of debridement in 12 cases). EPW culture had a positive predictive value of only 5.7% and a high negative predictive value (95.9%) for the diagnosis of PSM, with an accuracy of 70.4%. However, the likelihood ratio of positive (1.27) and negative (0.89) tests indicated only small changes in pretest-to-posttest probability. Therefore, a strategy of routine culture of EPWs to predict PSM seems questionable.

Adolescent↗
PubMed2004

The risk of reoperative heart valve procedures in Octogenarian patients.

BACKGROUND AND AIM OF THE STUDY: The authors' experience is reported of cardiac reoperations for valvular heart disease in octogenarian patients. METHODS: The records of 22 consecutive patients (10 men, 12 women) aged > or =80 years (mean age 82.4+/-2.3 years) who underwent cardiac reoperation for aortic and/or mitral valvular heart disease at the authors' institution between 1991 and 2001 were retrospectively reviewed. RESULTS: Indications for reoperation were structural dysfunction of a previously implanted bioprosthetic valve in 11 patients (50%), new valvular heart disease in six (27%), progression of rheumatic valvular heart disease in four (18%), and prosthetic valve infective endocarditis in one patient (5%). Fourteen patients (64%) underwent isolated aortic valve replacement (AVR), two (9%) had AVR plus coronary artery bypass grafting (CABG), one patient (5%) had aortic root replacement plus CABG, three patients (14%) had isolated mitral valve replacement (MVR), one patient (5%) had MVR plus ascending aorta replacement, and one (5%) had AVR plus MVR. Postoperative complications occurred in 18 patients (82%). The hospital mortality rate was 32%. Actuarial survival estimates at one year, and at three and five years were 62.6%, 56.3% and 40.2%, respectively. CONCLUSION: Cardiac reoperations for valvular heart disease in octogenarians carry a high postoperative morbidity and mortality. These findings must be taken into account in the management of associated mild or moderate valvular heart disease, and in the choice of heart valve prosthesis at the initial operation in younger patients.

Aged↗
PubMed2002

Nosocomial infections occurring during receipt of circulatory support with the paracorporeal ventricular assist system.

This retrospective study sought to report the spectrum of infections in a homogenous group of 39 patients who underwent implantation of the Thoratec paracorporeal ventricular assist device system (Thoratec Laboratories) in an emergency setting. Thirty-one of the 39 patients developed a total of 99 nosocomial infections (attack rate, 79.5%; incidence, 4.9 per 100 support-days). The lungs were the most frequently involved site (31.3%), and coagulase-negative Staphylococcus species were the pathogens most frequently isolated (16.2%). Infected patients required more transfusions and chest surgical revisions, as well as a longer duration of mechanical ventilation and a longer stay in the intensive care unit, compared with uninfected patients. Cox regression analysis revealed that chest surgical revision was the only independent risk factor for infection at any site (odds ratio, 2.6; 95% confidence interval, 1.2-5.7). There was no significant effect of infection on heart transplantation rate and overall survival.

Adult↗
PubMed2002

Aortic wall alterations after use of gelatin-resorcinol-formalin glue.

We report the case of a patient who underwent reoperation 8 years after aortic valve replacement because of aneurysmal dilatation of the aortic root. During the initial intervention, gelatin-resorcinol-formalin glue had been applied on the outside of the aortic root. Perioperative examination revealed a necrotic appearance of the right coronary sinus, with contained ruptures at two different sites. Histologic analysis showed major destruction of the aortic root media, leading to vascular wall thinning and rupture. The use of gelatin-resorcinolformalin glue may expose patients to major alterations of the aortic wall.

Aorta, Thoracic↗
PubMed2002

Risk factor analysis for proximal and distal reoperations after surgery for acute type A aortic dissection.

OBJECTIVE: This study was undertaken to determine significant risk factors for proximal or distal reoperations after surgical correction of acute type A aortic dissection. METHODS: Between 1980 and 2000, a total of 160 consecutive patients (mean age 57.5 +/- 13.3 years, 126 men) underwent surgery for acute type A aortic dissection. Proximal repair was performed by means of ascending aorta replacement with valve resuspension in 130 cases (81.3%), composite graft replacement in 19 cases (11.9%), separate aortic valve and ascending aorta replacement in 7 cases (4.4%), and aortic repair in 1 case (0.6%). Distal repair required arch replacement in 23 cases. Follow-up time averaged 4.51 +/- 5.6 years per patient. RESULTS: Survival estimates after initial operation were 66.1% +/- 3.8%, 57.7% +/- 4.2%, 52.2% +/- 4.6%, and 42.5% +/- 5.8% at 1, 5, 10, and 15 years, respectively. Thirty patients required 37 reoperations at a mean interval of 5.7 +/- 4.5 years after the initial operation. Freedoms from reoperation were 96.9% +/- 1.8%, 74.7% +/- 5.3%, 60.8% +/- 6.8%, and 39.3% +/- 9.1% at 1, 5, 10, and 15 years, respectively. Reoperations included procedures on the proximal aorta (aortic root or valve) in 21 cases and on the distal aorta or its side branches in 19 cases. Cox regression analysis distinguished severe preoperative aortic valve insufficiency as the only significant risk factors for proximal reoperation; younger patient age, more distal extent of dissection, and more recent operative date were found to be significant risk factors for distal reoperation. CONCLUSION: Patients with acute type A aortic dissection who have severe aortic valve insufficiency are at increased risk for proximal reoperation. These patients should benefit from a more aggressive proximal repair at initial operation. Distal extent of aortic resection at initial operation did not significantly influence the risk of distal reoperation.

Acute Disease↗
PubMed2002

Long-term results of the bentall operation versus separate replacement of the ascending aorta and aortic valve.

BACKGROUND AND AIMS OF THE STUDY: Aortic valve disease associated with ascending aorta dilatation can be treated either by separate replacement of the aortic valve and ascending aorta, or by a composite valved graft. METHODS: Between 1974 and 1999, 117 patients underwent a Bentall operation (BP), and 63 a separate replacement procedure (SP) of the ascending aorta and aortic valve. Anatomic lesions were dystrophic aneurysm in 79 patients, annuloectasia in 65, chronic dissection in 14, acute dissection in 18, and other etiology in four. Mean follow up was 3.45+/-3.47 and 8.75+/-6.8 years in the BP and SP groups, respectively. RESULTS: Early mortality was 7.7% in the BP group versus 11% in the SP group (p = NS). Actuarial survival at 10 years postoperatively in these groups was respectively 77.7+/-5.6% versus 75.8+/-6.9% (p = NS). However, freedom from late complication of the ascending aorta was significantly different (97.3+/-1.9% versus 68.3+/-9.0% at 10 years postoperatively). SP was identified as a risk factor for late complication of the ascending aorta by multivariate analysis (p = 0.01; odds ratio = 9). No statistical difference was observed on late reoperation rates. CONCLUSION: Separate replacement of the ascending aorta and aortic valve carries a higher complication rate for the remaining ascending aorta on long-term follow up when compared with the Bentall procedure. However, there were no differences in terms of late mortality.

Adult↗