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Biomedical subjects

D Loisance

Publications and source records attributed to D Loisance.

At least 19 recordsLinked to original sources
PubMed2006

B-type natriuretic peptide to assess haemodynamic status after cardiac surgery.

BACKGROUND: B-type natriuretic peptide (BNP) is the most powerful hormonal marker of left ventricular dysfunction and could be considered as an indicator of ventricular preload. The aim of this prospective study was to compare the respective value of BNP and cardiac filling pressures to assess the response to volume load after cardiac surgery. METHODS: Thirty-seven mechanically ventilated patients suffering from acute circulatory failure immediately after cardiac surgery, and equipped with a pulmonary-artery catheter were included. All haemodynamic measurements were taken before and after volume expansion using 500 ml of 4% modified fluid gelatin. RESULTS: Fifteen patients were volume responders (CI increase>or=15%) and 22 were non-responders. Right atrial pressure, pulmonary-artery occlusion pressure and BNP before volume loading were not significantly different between the responders and non-responders. BNP concentration before volume infusion significantly correlated to preoperative left ventricular ejection fraction, aortic cross-clamping time, serum creatinine, mean pulmonary arterial pressure and intensive care unit duration whereas no correlation was found with pulmonary-artery occlusion pressure or cardiac index. CONCLUSION: BNP level after cardiac surgery was influenced by many perioperative variables, limiting its usefulness as an indicator of cardiac preload or a predictor of volume responsiveness in this population.

Aged↗
PubMed2006

Embolic and bleeding events after modified Bentall procedure in selected patients.

AIM: As valve-sparing procedures gain increasing popularity, the long-term results of the total aortic root replacement (TARR) were evaluated using mechanical valve grafts in selected patients. METHODS AND RESULTS: From January 1993 to December 2003, 100 patients (87 men), aged >65 years (mean 51 (SD 10.4 years), presenting with isolated aortic root dilatation with or without aortic valve insufficiency, undergoing elective root replacement using a mechanical valve graft were reviewed. The aetiology of aortic root disease was degenerative in 69 patients and related to the bicuspid aortic valve in 31 patients. In 11 patients, concomitant coronary artery bypass graft was performed. Hospital mortality was 4%. Overall survival was 93.9% (2.4%), 89.1% (3.5%) and 83.2% (5.2%) at 1, 5 and 7 years, respectively. 14 patients experienced 45 embolic events (3.21 (2.64) events/patient; range: 1-10 events). Thus, the linearised rate of embolic events was 10.3 per 100 patient-years (95% confidence interval (CI) 7.29 to 13.31). The actuarial embolism-free survival was 96.6% (1.9%), 77.1% (6%) and 74.3% (6.4%) at 1, 5 and 7 years, respectively. The linearised rate of bleeding events was 2.2 per 100 patient-years (95% CI 0.87 to 3.71). Actuarial bleeding free survival was 95.6% (2.1%), 93.2% (2.6%) and 87.7% (5.8%) at 1, 5 and 7 years. respectively. None of the patients required reoperation and no cases of structural or non-structural valve dysfunction were observed. CONCLUSIONS: TARR using mechanical valve grafts yields excellent survival results in selected patients. However, a high rate of minor thromboembolic events was recorded. Aspirin in combination with oral anticoagulants might be of potential interest in these patients.

Adolescent↗
PubMed2005

[Blood activation during long-term mechanical circulatory support].

Mechanical circulatory support has become an approved treatment option for patients with cardiogenic shock or end-stage heart failure. However, recipients of heart assist devices are prone to high incidences of bleeding, thrombo-embolic and infectious complications. The occurrence of these complications is favoured by systemic alterations of coagulation and fibrinolysis, inflammation and immune responses. Several studies have evaluated these pathophysiological changes in patients undergoing long term circulatory support with pulsatile devices. However, the systemic consequences of the more recently introduced rotary blood pumps remain largely unknown. The present review focuses on the systemic consequences of long term circulatory support with pulsatile and non-pulsatile devices.

Assisted Circulation↗
PubMed2004

Local endovascular treatment of aortic aneurysms. From operating theater to lab bench.

Current treatment of aortic abdominal aneurysms by conventional surgery or endoprosthesis is flawed by high post-operative mortality and unpredictable durability of haemodynamic exclusion, respectively. We have developed endovascular approaches with cell and gene transfer, aimed at controlling further diameter expansion in an animal model of already-developed aneurysms in rats. Preliminary results suggest that both cell and gene endovascular therapy can be used to control expansion of aneurysms generated by inflammation and proteolytic destruction of the aortic wall.

Animals↗
PubMed2001

Poststernotomy mediastinitis due to Staphylococcus aureus: comparison of methicillin-resistant and methicillin-susceptible cases.

The objective of the study was to compare the outcome of poststernotomy mediastinitis (PSM) caused by methicillin-resistant and methicillin-susceptible Staphylococcus aureus (MRSA and MSSA, respectively). Hospital records of 41 patients with S. aureus PSM who were all treated by closed drainage from 1 April 1996 through 1 February 2000 were reviewed. PSM was caused by MRSA in 15 patients and by MSSA in 26. Follow-up (+/-SD) averaged 12.5+/-14.0 months per patient. Both groups had similar perioperative characteristics. Patients with MRSA PSM had a significantly lower actuarial survival rate than did patients with MSSA PSM (60.0%+/-12.6%, 52.5%+/-3.4%, and 26.3%+/-19.7% versus 84.6%+/-7.1%, 79.0%+/-8.6%, and 79.0%+/-8.65 at 1 month, and at 1 and 3 years, respectively; values are +/- SD; P=.04). PSM-related death and treatment failure were significantly higher in the MRSA group than in the MSSA group (P=.03 and.02, respectively). Logistic regression analysis revealed that MRSA was the only independent risk factor for overall mortality. In conclusion, the clinical outcome of PSM caused by MRSA is poorer than that caused by MSSA.

Adult↗
PubMed2001

The freestyle stentless aortic bioprosthesis: more about the subcoronary technique.

Two years after aortic valve replacement with a Freestyle stentless aortic xenograft using the partial scallop inclusion technique, late prosthetic valve endocarditis developed with abscess formation in the space between the porcine and native human aortic wall. The presence of such a periprosthetic dead space exposes the patient to increased postoperative pressure gradients and the risk of superinfection.

Aged↗
PubMed2001

Norepinephrine release after acute brain death abolishes the cardioprotective effects of ischemic preconditioning in rabbit.

OBJECTIVE: Brain death (BD) abolishes the infarct-limiting effect of ischemic preconditioning (IP) in rabbits. We wished to define the role of the norepinephrine storm in this observation. METHODS: Rabbits were randomized into six groups of ten animals each. In control group (CTRL), anaesthetized rabbits were subjected to 30 min left coronary marginal branch occlusion and 90 min reperfusion. In CTRL+IP group, anaesthetized rabbits were preconditioned with a 5-min ischemia and 5-min reperfusion sequence before coronary occlusion. In CTRL+NE+IP group, anaesthetized rabbits received a 10 microg/kg norepinephrine injection 90 min before IP. In BD group, rabbits were subjected to 90 min of BD before coronary occlusion. In BD+IP group, brain-dead rabbits were preconditioned before coronary occlusion. In BD+LA+IP group, rabbits received an intra-arterial bolus injection of an alpha and beta adrenoreceptor blocking agent (labetolol, 1 mg/kg) prior to brain death induction and subsequent preconditioning. BD was induced by rapid inflation of an intracranial balloon. At termination of the experiment, left ventricular volume (LVV), myocardial volume at risk (VAR) and infarct volume (IV) were determined with methylene blue and tetrazolium staining, and measured using planimetry. RESULTS: LVV was not significantly different among groups. Myocardial VAR/LVV was not significantly different between groups (CTRL, 22.5+/-6.9%; CTRL+IP, 23.3+/-2.2%; CTRL+NE+IP, 25.9+/-12.7%; BD, 19.9+/-4.8%; BD+IP, 21.7+/-3.1%; BD+LA+IP, 23.4+/-5.8%; P=NS). IV/VAR was significantly reduced in the CTRL+IP group as compared with CTRL and CTR+NE+IP groups (12.2+/-1.2 vs. 49.7+/-1.7 and 49.3+/-4.7%; P<0.0001). There was no significant difference in IV/VAR between BD and BD+IP groups. In contrast, IV/VAR was reduced in BD+LA+IP compared to BD and BD+IP groups (13.9+/-5.4 vs. 50.0+/-1.4 and 49.6+/-1.5%; P<0.001). CONCLUSION: The loss of infarct-limiting effect of IP in brain-dead rabbits is related to the massive release of norepinephrine that occurs as a consequence of BD.

Animals↗
PubMed2001

Immunologic events and long-term survival after combined heart and kidney transplantation: a 12-year single-center experience.

BACKGROUND: In this study we compare the incidence of cardiac rejection and long-term survival after combined heart and kidney transplantation (HK) and single heart transplantation (H). Combined HK transplantation is a surgical option for patients with irreversible cardiac and renal failure. However, long-term results of combined HK transplantation on immunologic events and patient survival remain unknown. METHODS: Between 1988 and 1997, 12 consecutive patients underwent combined HK transplantation (HK group) at a single institution. A control group (H group) of 24 single heart transplant recipients operated on within the same period was matched for age, pre-operative pulmonary vascular resistance, hepatic insufficiency and gender mismatch. Recipients and donors were ABO compatible without HLA antigen matching. All patients received immediate triple immunosuppression that included cyclosporine. Because of early renal dysfunction, cyclosporine was switched to anti-thymocyte globulin in 5 patients from the HK group and in 1 patient from the H group (p = 0.01). RESULTS: Actuarial freedom from heart rejection at 6 months and at 1 year following transplantation averaged 90 +/- 9% and 70 +/- 14% in the HK group, and 65 +/- 10% and 49 +/- 11% in the H group, respectively (p = 0.023). Actuarial survival at 1, 5 and 12 years was not significantly different between groups, at 66%, 55% and 28% in the HK group, and 66%, 44% and 32% in the H group, respectively (p = 0.66). CONCLUSION: The incidence of cardiac rejection was significantly lower. Long-term survival in the HK group was similar to that in the H group. Putative mechanisms of decreased cardiac rejection in the HK group include allogeneic stimulation, donor-derived dendritic cells and induction by anti-thymocyte globulins. The need for long-term immunosuppression may be reduced after combined heart and kidney transplantation.

ABO Blood-Group System↗
PubMed2001

Silzone-coated St. Jude medical valve: a safe valve.

Careful follow up studies in patients receiving a Silzone-coated St. Jude Medical valve (67 aortic valves, 36 mitral valves, nine double valves) did not support the fear of a high risk of perivalvular leak and embolism rate. Freedom from perivalvular risk at 12 and 24 months follow up was 98.5+/-1.5% and 100% for the aortic and mitral valves, respectively. Freedom from any thromboembolic event was 96.6+/-2.4% at 12 and 24 months follow up in the aortic group, and 97+/-3% at 12 and 24 months in the mitral group. The risk of bleeding (92.2+/-3.8% at 12 and 24 months in the aortic group; 85.5+/-6.0% in the mitral group) illustrated the risk of mechanical valve implantation in an elderly population.

Actuarial Analysis↗
PubMed2001

[Long-term results of surgery for type A acute aortic dissection].

The cases of 160 patients (126 men, mean age 57.5 +/- 13.3 years) operated consecutively as an emergency for a Stanford type A dissection of the aorta between 1980 and 2000 were reviewed. The cumulative follow-up was 716.7 patient-years with an average follow-up of 4.51 +/- 5.6 patient-years. The risk factors for early postoperative mortality (up to 3 months), late mortality (> 3 months) and reoperation (cardiac and/or vascular) were determined by multivariate analysis. The hospital mortality was 27.5%. Older ages, obesity, previous cardiac surgery, preoperative shock, medullary, renal or mesenteric ischaemia were significant risk factors for early mortality. The probability of actuarial survival was 66.1 +/- 3.8%, 57.7 +/- 4.2%, 52.2 +/- 4.6% and 45.3 +/- 5.5% respectively at 1, 5, 10 and 15 years. Chronic obstructive airways disease and a more recent operation date were significant risk factors for late mortality. Thirty patients underwent 37 reoperations after an average of 5.7 +/- 4.5 years. The actuarial probability for no reoperation was 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. The presence of severe preoperative aortic regurgitation was the only significant risk factor for reoperation. Type A acute dissection of the aorta continues to have a high early mortality and a significant incidence of late complications. Patients with severe aortic regurgitation before surgery are at high risk for reoperation and should probably have more radical aortic repair at the initial operation.

Acute Disease↗
PubMed2001

[Computer-assisted coronary surgery].

Routine totally endoscopic, beating heart, coronary surgery should be made possible by the use of computer enhanced surgical techniques. It includes a totally endoscopic mammary artery harvesting, a correct exposure and an adequate stabilization of the coronary artery at the anastomotic site, a perfect anastomosis of the mammary artery on the left anterior descending coronary artery using a microsurgical suture technique. This complex surgical protocol will be reached by a step by step approach. The first 20 patients who accepted to be operated with tele-manipulated instruments make the substance of this first report. In 19 cases, the dissection of the internal mammary artery could be performed with an optimal result: the lack of bleeding during the dissection emphasizes the excellent visualization of the operative field and the precision of the dissection. The satisfactory blood flow in the mammary artery at the time of the coronary anastomosis suggests the lack of spasm and confirms the atraumatic dissection. The distal anastomosis of the coronary bypass has been performed through a mid line sternotomy to avoid an excessive prolongation of the operative time. The anatomic conditions and the quality of the vessel wall allowed to perform the coronary anastomosis with the tele-manipulated instruments in nine cases only: in six patients, the mammary artery has been implanted on the descending artery, in three, a venous autograft on the diagonal branch. Our initial clinical experience with this new technique suggests that a very precise and fine surgery can be performed with an acceptable prolongation of the operative time. More experience and further developments in the instrumentation are nevertheless required to allow completion of the entire procedure totally closed chest, on a beating heart.

Aged↗
PubMed2000

[Circulatory assistance while waiting for heart transplantation. Patient selection and choice of the assist system].

TWO CLINICAL SITUATIONS: Mechanical circulatory assistance can be indicated in two clinical situations: i) patients on the waiting list for heart transplantation who have chronic heart failure unresponsive to drug therapy and whose clinical status worsens; ii) patients with acute heart failure. INDICATIONS: The exact indications for mechanical circulatory assistance are difficult to establish. Hemodynamic criteria are no longer sufficient. Circulatory assistance may be proposed for chronic heart failure patients with a high risk of death or in a situation of acute deterioration. Among these patients, several risk factors can be used to establish scores that have a better predictive value than risk factors taken alone. Two predictive models have been recently established. The first one takes into account 7 independent variables: etiology, heart rate at rest, left ventricle ejection fraction, mean blood pressure, intraventricular rhythm disorder, VO2max and serum sodium). In addition to these variables, the second model also includes pulmonary wedge pressure. In selected patients with acute heart failure, circulatory assistance is needed as early as possible to avoid irreversible multiple organ failure. The crucial problem is rapid assessment of the feasibility of heart transplantation. PREOPERATIVE MORTALITY RISK FACTORS: Several variables can be used to predict survival in candidates for mechanical circulatory assistance on the heart transplantation waiting list. They include hemodynamic criteria, renal function, liver function, preoperative infection and the emergency nature of the need for circulatory assistance. CHOICE OF THE ASSIST SYSTEM: The choice depends both on the patient (surface area is important) and the underlying disease.

APACHE↗
PubMed2000

[Circulatory assistance while waiting for heart transplantation. Clinical course].

OUTCOME: In most cases, mechanical circulatory assistance prior to transplantation can restore the main vital functions allowing a progressive physical rehabilitation during the period of assistance. According to several international registries, the transplantation rate ranges from 62% to 69% and the proportion of transplanted patients who had circulatory assistance and who were discharged ranges from 65% to 69%. COMPLICATIONS: Bleeding (42.5%), right heart failure (20-25%), air embolism and multiple organ failure are the main causes of early morbidity and mortality. Infection (28.5%), thromboembolic events and technical failures are the most frequent late complications. DURATION OF CIRCULATORY ASSISTANCE: The optimal time for transplantation is the moment when the incidence of complications and technical problems for transplantation are at their minima while the patient's vital functions are at their maxima.

Assisted Circulation↗
PubMed2000

[Circulatory assistance while waiting for heart transplantation. Outcome of heart transplantation after mechanical circulatory assistance].

SURVIVAL: In most of the published (uncontrolled) studies, survival after transplantation is similar for patients who required mechanical circulatory assistance and those who did not. Two controlled studies have reported a better survival rate in patients who had preoperative circulatory assistance. COMPLICATIONS: Infections are more frequent in transplanted patients who had a period of circulatory assistance preoperatively than in those who were transplanted after medical treatment. The effect of circulatory assistance on heart graft rejection is debated. The same is true for coronary grafts.

Assisted Circulation↗
PubMed2000

Acute brain death abolishes the cardioprotective effects of ischemic preconditioning in the rabbit.

BACKGROUND: Myocardial preconditioning with brief coronary artery occlusions before a sustained ischemic period is reported to reduce infarct size. We wished to evaluate whether ischemic preconditioning (IP) is efficient in an experimental brain death (BD) model in the rabbit. METHODS: Rabbits were randomized into four experimental groups of eight animals each. In the control group (CTRL), anaesthetized rabbits were subjected to 30 min of left coronary marginal branch occlusion and 90 min of reperfusion without any pretreatment. In the CTRL+IP group, anaesthetized rabbits were preconditioned with a 3-min ischemia and 3-min reperfusion sequence before coronary occlusion. In the BD group, rabbits were subjected to 90 min of BD before 30 min of coronary occlusion and 90 min of reperfusion. In the BD+IP group, BD rabbits were preconditioned as in the CTRL+IP group before coronary occlusion. BD was induced by rapid inflation of an intracranial balloon and was validated by clinical and electroencephalographic examinations. At the termination of the experiment, left ventricular volume (LVV), myocardial volume at risk (VAR) and infarct volume (IV) were determined with methylene blue and tetrazolium staining and were measured using planimetry. RESULTS: LW was not significantly different among the four experimental groups (CTRL, 6.54+/-0.90 cm3; CTRL+IP, 5.92+/-0.60 cm3; BD, 5.87+/-0.81 cm3; BD+IP, 6.16+/-0.95 cm3; P=ns). Furthermore, myocardial VAR, expressed as a percentage of LVV, was not significantly different between groups (CTRL, 20.0+/-4.2%; CTRL+IP, 22.32+/-2.25%; BD, 21.38+/-3.36%; BD+IP, 21.64+/-3.39%; P=NS). IV, expressed as a percentage of VAR, was significantly reduced in the CTRL+IP group compared with the CTRL group (15.76+/-8.47% vs. 49.95+/-1.51%; P<0.0001). In contrast, there was no significant difference in IV, expressed as a percentage of VAR, between the BD and the BD+IP groups (50.0+/-1.52% vs. 49.72+/-1.58%; P=NS). CONCLUSION: The data indicate that the infarct-limiting effect of IP is lost in BD rabbits. Thus, the clinical potential of IP in the context of organ transplantation seems to be severely compromised.

Analysis of Variance↗
PubMed2000

Cardiac troponin I release after open heart surgery: a marker of myocardial protection?

BACKGROUND: Unlike creatine kinase MB isoenzyme, cardiac troponin I (cTnI) is a highly specific marker of myocardial injury. Its release has recently been studied after coronary artery bypass grafting operation. However, its significance after open heart surgery (OHS) remains to be determined. This protein release could be a marker of myocardial protection. We sought to study cTnI release after OHS in patients with normal coronary arteries and to compare it with cTnI release in patients after coronary artery bypass graft (CABG) surgery. METHODS: Eighty-five patients undergoing OHS and 86 patients undergoing CABG were enrolled in the study. CTnI concentrations were measured in serial venous blood samples drawn before surgery and immediately, 12 hours, 24 hours, 48 hours, and 5 days after aortic unclamping. RESULTS: In the OHS group and in the CABG group without acute myocardial infarction (AMI), cTnI peaked at 12 hours postoperatively (6.35 +/- 6.5 and 5.38 +/- 8.55 ng/mL, respectively) and normalized on day 5 postoperatively (0.57 +/- 2 and 0.72 +/- 1.62 ng/mL, respectively). CTnI concentration did not differ significantly between the OHS group and the CABG group in the absence of AMI for any samples considered. In the CABG group, 2 patients had AMI. In the OHS group, cTnI levels at 12 hours postoperatively were found to correlate closely with CPB and aortic cross-clamping (ACC) times, contrary to the CABG group, which correlated only with occurrence of AMI. CTnI release was independent of age and ejection fraction in either group. CONCLUSIONS: cTnI release in patients after OHS with normal coronary arteries has the same profile as cTnI release in patients after CABG in the absence of AMI. However, its peak at 12 hours postoperatively is only correlated to ACC and CPB times, which is contrary to cTnI release after CABG surgery. This observation suggests that cTnI could be a marker of myocardial ischemia after OHS.

Adult↗