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P Boissonnat

Publications and source records attributed to P Boissonnat.

At least 37 records · Page 2Linked to original sources
PubMed1995

[Value of coronary angiography in the diagnosis of coronary artery disease of the transplanted heart. Coronary angiography and arteriosclerosis of the graft].

The diagnostic value of coronary angiography, a widespread method of detection of transplant coronary artery disease, was studied in 17 cardiac transplant patients with reference to histological examination. In the 6 coronary segments studied, the only significant but weak correlation that was found was for the distal left anterior descending artery: the correlations were not statistically significant in the other 5 segments. Coronary angiography underestimated lesions and false negative results were frequently reported (66 and 27% respectively). The limitations of coronary angiography may be explained by the technical artefacts related to both methods of evaluation and the anatomically diffuse and distal nature of transplant coronary artery atherosclerosis. A more reliable diagnostic method would seem to be required in view of the clinical importance of this pathology.

Coronary Angiography↗
PubMed1994

The beneficial effect of dietary antioxidant supplementation on platelet aggregation and cyclosporine treatment in heart transplant recipients.

To determine whether dietary antioxidant supplementation can reduce platelet reactivity in heart transplant recipients, 20 patients were prospectively randomized to receive either 500 IU vitamin E orally per day in the form of acetate for 2 months or no vitamin E. Blood creatinine (P = 0.01) and lymphocyte count (P = 0.009) significantly decreased only in supplemented patients, whereas the cyclosporine blood level was not modified. Platelet aggregation was stable in control patients but significantly decreased in supplemented patients in response to either thrombin (from 8.3 +/- 0.9% of maximum aggregation to 3.7 +/- 0.7, P = 0.001) or ADP (secondary wave: from 44.7 +/- 5.9% to 33.2 +/- 7.0, P = 0.02). Thus antioxidant supplementation tended to improve immunosuppression (by reducing lymphocyte count), to reduce cyclosporine nephrotoxicity, and to decrease the high thrombotic risk associated with heart transplantation.

Administration, Oral↗
PubMed1994

Platelet aggregation and HDL cholesterol are predictive of acute coronary events in heart transplant recipients.

BACKGROUND: Sudden death (SD) and acute myocardial infarction (AMI) are the main complications limiting long-term survival after heart transplantation (HT). They are unpredictable and, at present, unpreventable. Platelet aggregation (PA) has recently emerged as a significant prognostic indicator in nontransplanted coronary disease patients. The main purpose of the present study was to evaluate to what extent PA could predict SD and AMI in long-term survivors of HT independently of serum lipid levels. METHODS AND RESULTS: We studied 207 patients. All received triple immunosuppressive therapy. During follow-up, the incidence of SD and AMI was determined, and the independent role of PA as predictor was evaluated with other usual risk factors by a Cox multivariate regression model. There were 11 SDs and 14 AMIs after an average follow-up of 642 days, giving an average incidence rate of 7.3 events per year per hundred patients. By univariate analysis, the most potent predictors were ADP-induced platelet aggregation (positive association) and total cholesterol (negative association). Age and length of time since transplant were not predictors. By multivariate analysis, only the secondary wave of ADP-induced platelet aggregation (P = .001) and high-density lipoprotein cholesterol (P = .03) were independent predictors. The relative risk of SD or AMI based on a comparison between patients with high (> 36%) or low (< 36%) ADP-induced platelet aggregation was 4.3 (95% confidence interval, 1.9 to 9.5, P = .0001). CONCLUSIONS: This study provides the first demonstration of an association between increased platelet aggregation and subsequent SD or AMI in HT recipients. It suggests that platelets and thrombosis also are implicated in the pathogenesis of AMI and SD in HT recipients. Identification of a safe and effective antiplatelet therapy should be actively pursued.

Adolescent↗
PubMed1993

Lipid peroxides and antioxidant defenses in accelerated transplantation-associated coronary arteriosclerosis.

Accelerated coronary artery disease develops in most if not all heart transplant recipients within the first year after transplantation. Increased lipid peroxidation seems to be involved in atherogenesis. In these patients we have investigated whether there is an association between lipid peroxidation, reduced antioxidant defenses, and some conventional coronary risk factors. Lipid peroxides, lipids, uric acid, albumin, antioxidant enzymes and their cofactors (the trace elements selenium, iron, copper, and zinc) have been determined in heart transplant recipients compared with nonrecipients with coronary artery disease. Lipid peroxides (p = 0.002) and uric acid (p = 0.01) were higher and zinc (p = 0.001) was lower in heart transplant recipients. Thirteen of 30 transplant recipients compared with one of 30 nonrecipients (p < 0.001) had very low (less than 10 mumol/L) zinc levels. Antioxidant enzymes and other trace elements were not significantly different. In univariate regression analysis, zinc correlated positively with albumin (p = 0.02) and negatively with lipid peroxides (p < 0.05). Uricemia had a strongly positive correlation with hydroperoxides (r = 0.45; p = 0.0001). In stepwise multivariate regression analysis, lipids, uricemia, creatinine, and zinc were significant (p < or = 0.004) predictors of the lipid peroxide level. Cyclosporine and corticosteroid dosages were significant (p = 0.01) determinants of zinc concentration in the transplant recipients. Although a causal relationship between increased lipid peroxidation and accelerated arteriosclerosis is not definitely demonstrated, the results of this analysis suggest new insights into conventional coronary disease risk factors and possible therapeutic interventions; further controlled trials are needed.

Adult↗
PubMed1993

Accelerated coronary artery disease after heart transplantation: the role of enhanced platelet aggregation and thrombosis.

The present study is a prospective examination of the relationship between platelet aggregation and the occurrence of graft failure in a single cohort of heart transplantation (HT) recipients. One-hundred-and-twenty-four patients underwent platelet function study and were then followed for 1 to 24 months (mean 6.7 months). There were nine re-transplantations and 13 deaths (11 related to ischaemic events, and two others). In 15 patients, pathologic examination confirmed or revealed that recent acute myocardial infarction was the obvious cause of the graft failure. In five patients, myocardial fibrosis related to severe and diffuse coronary disease was the only microscopic finding. In the last two patients, the cause of the heart failure was not clearly identified. In recent myocardial infarction there was a high incidence (14/15) of coronary thrombi. Thrombi were multiple, disseminated in the coronary tree end of different age. Their presence at autopsy or after explantation was associated with an enhanced ex vivo platelet aggregability as compared with patients without coronary thrombi (n = 8): 43.3 +/- 1.7% of maximal aggregation vs. 34.4 +/- 2.4 (P = 0.006) and 48.4 +/- 5.2 vs. 22.6 +/- 4.9 (P = 0.003) for the primary and secondary waves of ADP-induced aggregation. These results suggest that thrombosis and platelets may play a major role in the process of accelerated coronary artery disease after HT.

Adult↗
PubMed1992

Pharmacokinetics of cyclosporine in hyperlipidaemic long-term survivors of heart transplantation. Lack of interaction with the lipid-lowering agent, fenofibrate.

Cyclosporine (Cy) binds to lipoproteins in plasma. In order to test if its pharmacokinetics would be modified when efficient lipid-lowering treatment is introduced, a study has been done of Cy pharmacokinetics and any interaction with the lipid-lowering agent fenofibrate in hyperlipidaemic long-term, survivors of heart transplantation. Fenofibrate 200 mg once daily significantly reduced blood lipids (cholesterol 6.5 vs 7.7 mmol/l; apoprotein B 1.2 vs 1.6 g/l) but did not modify mean whole blood Cy trough levels (113 before fenofibrate vs 103 ng.ml-1), Cmax (812 ng.ml-1 by RIA and 757 ng.ml-1 by HPLC before fenofibrate versus 865 and 741 respectively, during fenofibrate); tmax (1.6 and 1.7 h before fenofibrate versus 1.4 and 1.4 h respectively), and t1/2 (13.9 and 11.1 h versus 9.5 and 10.7 h). The only adverse effect was an increase in creatinine (157 vs 145 mmol/l). Further studies are needed to investigate the mechanism of Cy-fenofibrate nephrotoxicity and to evaluate the long-term efficiency and safety of fenofibrate after heart transplantation.

Adult↗
PubMed1992

Platelet function and composition in heart transplant recipients compared with nontransplanted coronary patients.

Accelerated coronary artery disease seems to be the main condition limiting long-term survival after heart transplantation. Ninety-one heart transplant recipients were compared with 94 nontransplanted coronary artery disease patients in an attempt to identify the factors responsible for the accelerated form of coronary artery disease occurring after heart transplantation. Among the parameters examined, heart transplant recipients exhibited a higher plasma level of insulin (8.5 +/- 0.5 versus 6.2 +/- 0.3 mIU/l, p = 0.002), a lower plasma level of vitamin E (14.8 +/- 0.4 versus 16.9 +/- 0.7 mg/l, p = 0.03), a higher platelet cholesterol-to-phospholipid ratio (8.9 +/- 0.3 versus 7.6 +/- 0.3, p = 0.007), and an increased response to ADP-induced platelet aggregation (for the first wave, 29.1 +/- 0.9% of maximal aggregation versus 25.1 +/- 1.0%, p = 0.002; for the second wave, 21.4 +/- 1.4% versus 15.9 +/- 1.1%, p = 0.002, after adjustment for hematocrit), but no untoward changes in the level of fibrinogen, plasminogen activator inhibitor-1, antithrombin III, or lipoprotein(a). In addition, platelet aggregation in patients who required retransplantation as a result of severe coronary artery disease was similar before and after retransplantation. This suggests that severe coronary artery disease is not the cause of platelet hyperaggregability. In multiple-regression analysis, ADP-induced platelet aggregation in heart transplant recipients was significantly positively related to blood glucose (r = 0.50, p less than 0.001) and inversely related to n-3 fatty acids from platelet phospholipids (r = 0.40, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗
PubMed1992

[Evaluation of non invasive methods for the diagnosis of atherosclerosis of the graft after orthotopic cardiac transplantation].

The frequency and severity of atherosclerosis of the cardiac transplant make it an essential complication of cardiac transplantation. Coronary angiography is the usual diagnostic method but it has severe limitations. In order to evaluate other diagnostic methods coronary angiography and non-invasive techniques: echocardiography, exercise stress ECG, exercise radionuclide ejection fraction, stress Thallium scintigraphy, were performed practically simultaneously in 60 patients after cardiac transplantation. These non-invasive methods were said to be positive in the presence of, respectively, a segmental wall motion abnormality, ischaemic ST segment depression, absence of increased ejection fraction on exercise, reversible or irreversible myocardial hypofixation. Coronary angiography was considered as the reference procedure for distinction between "normal coronary circulation" (no angiographically detectable lesion) and "graft atherosclerosis" (at least one coronary stenosis irrespective of the severity and extension). None of the non-invasive methods had an adequate sensibility when compared with coronary angiography (echocardiography 0.27, exercise stress ECG 0.28, exercise radionuclide ejection fraction 0.64, myocardial scintigraphy 0.62) or negative predictive value (echocardiography 0.56, exercise stress ECG 0.58, exercise radionuclide ejection fraction 0.68, myocardial scintigraphy 0.66). This inadequacy of the non-invasive technique may be explained by the fact that they are more adapted to the diagnosis of myocardial ischaemia than that of coronary studies. In addition, the extent of the coronary lesions may have masked discordance between 2 segments by the global hypovascularisation. The results of this study indicate that the non-invasive methods studied cannot be recommended for diagnosis of atherosclerosis of cardiac transplants.

Adult↗
PubMed1992

[Coronary accelerated arteriosclerosis and vasospasm in the transplanted heart].

Accelerated atherosclerosis of cardiac grafts is one of the factors limiting long-term survival after cardiac transplantation. The authors report the case of a patient who had a cardiac arrest associated with severe atherosclerosis 18 months after transplantation. The severity of the coronary lesions was underestimated by coronary angiography. An ergometrine test induced coronary spasm, a phenomenon which has only rarely been observed in transplanted hearts. The patient died one month later despite calcium inhibitor therapy. Autopsy revealed very severe triple vessel disease. This case illustrates the possible rapid evolution of coronary artery disease in cardiac transplant recipients, the difficulty in evaluating the severity of the lesions by coronary angiography and the additional possibility of observing coronary spasm in these cases.

Coronary Angiography↗
PubMed1991

[Coronary lesions of a cardiac transplant. (Chronic cardiac rejection). Study of 15 retransplantations].

In order to precise the pathologic aspects of coronary lesions observed in the accelerated coronary disease after heart transplantation, 15 cases of explanted hearts have been studied, and compared to the findings of previous coronarography. Histopathological aspects, modes of diffusion involving the three main coronaries and distal branches, thrombotic complications and their ischemic consequences showed that coronary lesions result in a few months or years to diffuse circumferential atheromatous like lesions. Localized lesions are less frequently encountered than in common atheromatous coronary disease, but multifocal thrombosis is frequent, found in 40% of the cases. This feature leads to ischemic cardiopathy expressed by cardiac failure, indolent because of the denervation of the heart. Correlations with coronarographies showed that this method underestimated the importance of coronary lesions, for which retransplantation represents the only hope. Risk factors include vascular immunological inflammation, viral infection enhanced by immunosuppression, increased platelet aggregation but we still ignore the respective importance of these factors at the present time.

Adult↗
PubMed1991

[Causes of failure analysis after cardiac transplantation. From a consecutive series of 91 cases].

Ninety-three cardiac transplantations were carried out in 91 patients (2 retransplantations) between March 1st 1987 and November 1st 1989, in 84 adults and 7 children under 15 years of age. The indications were dilated cardiomyopathy (48%), ischemic cardiomyopathy (35%), decompensated valvular heart disease (11%), congenital heart disease (3%) and two cases of Uhl's anomaly. Twelve patients underwent transplantation after external circulatory assistance (13%), 11 patients after inscription on the list of extreme emergencies, and 68 on an elective basis (74%). The postoperative immunosuppressive protocol was triple therapy: Ciclosporine, Azathioprine and Prednisone. Three of the children died. The early adult mortality was 9 cases (10.7%). It was 8% in patients operated electively. Major infectious complications occurred in 10 patients (11%). Rejection was looked for by systematic endomyocardial biopsy and echocardiography. Three hundred and forty-nine biopsies were made. Thirty-five patients (44%) had no problems of rejection. Seventy-nine patients have now been followed up for an average of 19 months. There were 7 late deaths. Seventy seven per cent of the survivors are asymptomatic. Acute rejection and transplant dysfunction were the two main causes of early mortality after cardiac transplantation. Although the long-term prognosis is uncertain, the medium-term results are very encouraging.

Actuarial Analysis↗
PubMed1990

Use of the Abiomed BVS System 5000 as a bridge to cardiac transplantation.

The Abiomed BVS System 5000 (Abiomed Cardiovascular, Inc., Danvers, Mass.) is a gravity-filled, pneumatically driven external prosthetic ventricle that has been implanted as a circulatory support device in six patients 9 to 58 years of age, presenting with a refractory heart failure nonamenable to any type of corrective operation. Three (including a 9-year-old girl) had an end-stage nonobstructive myocardiopathy, and two (including one patient who had had a massive recent myocardial infarction) had an ischemic heart disease. When first seen, the 58-year-old patient had an acute rejection and graft failure occurring 2 months after a first transplantation. All patients showed evidence of a low-output state (cardiac index less than 1.5 L/min/m2), with renal failure (mean urinary output, less than 27 ml/min) and hypoxia (mean arterial oxygen pressure = 56 torr under 80% forced inspiratory oxygen), despite maximum pharmacologic support (dobutamine, 16 to 18 gamma/kg/min; dopamine, 3 to 18 gamma/kg/min; adrenaline, 0.2 to 0.7 gamma/kg/min; furosemide, 7 to 17 gamma/kg/min). The device was implanted through a midline sternotomy and under peripheral normothermic bypass. Five patients received a biventricular support, and one a single left prosthetic ventricle. The cannulation included a right-angled cannula in both the left and right atrium and a suture of the arterial Dacron tubes onto the ascending aorta and main pulmonary artery. After careful deairing of the tubing and ventricles, the console was activated and the bypass progressively discontinued. Heparin infusion was begun 3 hours after chest closure and was continued for the duration of assist pumping, which was 2 to 11 days (mean duration, 7.43 days). The system could provide a complete support of the circulation with both right and left ventricular index remaining stable at 2.4 to 3 L/min/m2. After a dramatic improvement at the time of the system activation, the urinary output remained adequate, thus allowing for a decreasing need for diuretic therapy. In two cases, including one of isolated left ventricular assist pumping, the circulation could be totally supported during 11 hours and 23 hours, respectively, of refractory ventricular tachycardia. Four of six patients were shortly weaned from inotropic agents. Hematologic studies showed a moderate decrease of the coagulation factors level during the first 6 hours of circulatory support, and this remained stable and within normal limits thereafter. There have been three cases of bleeding complications necessitating surgical revision on the sixth hour, the twelfth hour, and the sixth day, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗