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Biomedical subjects

J Robin

Publications and source records attributed to J Robin.

At least 37 records · Page 2Linked to original sources
PubMed1998

Mechanical versus biological isolated aortic valvular replacement after the age of 70: equivalent long-term results.

OBJECTIVE: In order to evaluate the long-term outcome of valvular substitutes in the elderly, we retrospectively analyzed two comparative groups of patients consecutively operated on by the same team for an isolated valvular aortic replacement using either a mechanical or a pericardial prosthesis. METHODS: From 1982 to 1996, 206 patients over 70 years (mean 76.5+/-4.4) underwent an isolated aortic valvular replacement using either a St. Jude Medical (Group I, n = 93) or a Mitroflow (Group II, n= 113) prosthesis depending on the surgeon's preference at the time of surgery. Both groups matched for the following pre-operative variables: sex ratio, type of aortic valve disease, NYHA status, cardiac rhythm, mean pulmonary arterial pressure, left ventricular end-diastolic pressure, LV-AO gradient, cardiac index and ejection fraction. RESULTS: Given an early mortality rate of 6.4% in Group I and 4.4% in Group II (NS), follow-up (mean 4.4+/-3.7 years in Group I and 5.3+/-3.1 years in Group II) was 100% complete. Actuarial survival was 69.9+/-6 and 70.2+/-4.6% at 5 years for Group I and Group II, respectively, and 49.6+/-7.7 vs. 51.4+/-6.3% at 10 years (NS). Freedom from valve-related death was 86.5+/-4.8% in Group I vs. 82.7+/-4% in Group II at 5 years (NS) and 66.7+/-8.7 vs. 66.3+/-7% at 10 years (NS). There were no anticoagulant-related deaths or severe accidents in Group 1. A secondary valvular replacement was necessary in 4 patients in Group II vs. none in Group I. CONCLUSION: The study shows a similar late survival in both groups, with a strikingly low incidence of anticoagulant-related deaths in this population. Given a higher rate of reoperation after biological valve replacement, the use of mechanical valve in this aging population seems to be a valid option.

Aged↗
PubMed1998

The hemodynamic effects of hypoxemia in anesthetized pigs: a comparison between right heart catheter and echocardiography.

UNLABELLED: During hypoxemia, hypoxic pulmonary vasoconstriction and tachycardia are often observed in association with increases in pulmonary artery pressure and cardiac output. Nevertheless, the hemodynamic consequences of hypoxemia have never been evaluated by echocardiography and simultaneously compared with invasive hemodynamic variables. Fourteen open-chest, anesthetized piglets (weight 29-36 kg) were submitted to progressive hypoxemia and reoxygenation. Usual invasive hemodynamic variables were obtained from peripheral and central heart catheters. Direct epicardial echocardiography was used to measure right and left ventricular areas on a short-axis view at mid-papillary level. The mean pulmonary artery pressure (MPAP) increased with pulmonary vascular resistance in a dose-related manner as the fraction of inspired oxygen (FIO2) declined from 0.5 to 0.12. The MPAP correlated with right ventricular end-diastolic area (RVEDA) only at FIO2 0.08. There was a 49% reduction in left ventricular end systolic wall stress (LVESWS) between FIO2 0.5 and 0.08. Left ventricular ejection fraction area (LVEFA) increased by 33% above baseline and correlated with the decrease in LVESWS. No correlation was observed between left ventricular end-diastolic area and pulmonary artery occlusion pressure or left atrial pressure and between cardiac output and LVEFA. Systemic vascular resistance underestimates the magnitude of changes in LVESWS but overestimates the afterload compared with LVESWS. This study demonstrates that, for the lowest FIO2 (0.08), changes in MPAP correlated with changes in RVEDA but not in pulmonary vascular resistance. Moreover, LVESWS decreases significantly in a dose-related manner under progressive hypoxemia and normalizes immediately after reoxygenation. This study also shows that, under hypoxemic conditions, echocardiography enhances understanding of hemodynamic changes compared with right heart catheterization alone. IMPLICATIONS: Acute hypoxemia in pigs is responsible for pulmonary vasoconstriction-induced pulmonary hypertension (which is restricted by the right ventricular failure), as well as a PaO2-dependent decrease in left ventricular afterload. These changes are better displayed by echocardiography than by right heart catheter.

Anesthesia↗
PubMed1998

Troponin I, troponin T, or creatine kinase-MB to detect perioperative myocardial damage after coronary artery bypass surgery.

STUDY OBJECTIVES: To compare cardiac troponin I (cTnI), cardiac troponin T (cTnT), and creatine kinase MB (CKMB mass) in patients with and without new Q wave on the ECG following coronary artery bypass graft (CABG) surgery. PATIENTS: After ethic committee's approval and informed consent, 82 patients, mean age 63+/-10 years, scheduled for CABG were included. INTERVENTIONS: Arterial blood samples were drawn during cardiopulmonary bypass, before, and 6, 12, 24, and 48 h after aortic cross-clamp release. cTnI, cTnT, and CKMB mass were measured. The appearance of new Q wave on the ECG performed preoperatively and 24 h postoperatively was used to assess myocardial lesion independently of biological markers. RESULTS: There were 69 patients without new Q wave on the ECG (group 1) and 13 with (group 2). In group 1, cTnI reached a peak of 2.1 microg/L (median, interquartile range [IQ]=2.4) at 12 h, cTnT increased progressively with a peak of 0.22 microg/L (IQ=0.2) at 48 h, and CKMB presented an earlier peak of 10 microg/L (IQ=6.2) at 6 h. Starting with the same median value, group 2 patients presented significantly higher peaks: cTnI: 17 microg/L (IQ=16) at 12 h; cTnT: 1.4 microg/L (IQ=2.3) at 12 h; and CKMB mass: 74 microg/L (IQ=61) at 6 h. Receiver operating characteristic (ROC) curves were constructed. The area under the curve was 0.90 for cTnI, 0.84 for CKMB, and 0.81 for cTnT (not significant). The best cutoff values to discriminate between group 1 and group 2 patients were determined with the ROC curves: cTnI=5 microg/L; CKMB mass=20 microg/L; cTnT=0.3 microg/L. Sensitivity, specificity, and positive and negative values for cTnI (5 microg/L) were 91%, 82%, 53%, and 98%, respectively. CONCLUSIONS: There was little differences among cTnI, cTnT, and CKMB after CABG to diagnose myocardial damage as assessed by new Q wave on the ECG. There was a trend of cTnI to be a better discriminator than cTnT, but it did not reach statistical significance.

Biomarkers↗
PubMed1997

Flow-induced release of endothelium-derived relaxing factor during pulsatile bypass: experimental study in the fetal lamb.

OBJECTIVE: This study was initiated to test the hypothesis that fetal hemodynamic changes observed under pulsatile flow bypass might be related to the release of endothelium-derived relaxing factor through oscillating shear stress. METHODS: Normothermic bypass was instituted in utero in 21 preterm fetal lambs for a 1-hour period through the right atrium and main pulmonary artery. Ultrasonic flowmeters were positioned around the descending aorta and the umbilical artery. The circuit consisted of an oxygenator and a pump set to either continuous flow (n = 7) or pulsatile flow (n = 7) and adjusted to maintain a fetal main arterial pressure of 50 mm Hg. In seven other animals, endothelium-derived relaxing factor was blocked by a continuous infusion of N omega-nitro-L-arginine after 30 minutes of pulsatile flow. RESULTS: During the first 30 minutes of bypass, pump flows were significantly lower in the continuous-flow group than in the pulsatile-flow or blocked-flow groups (respectively, 612 +/- 144, 907 +/- 153 and 987 +/- 228 ml/min), with similar changes in aortic and umbilical flows. Systemic vascular resistances were significantly lower in the pulsatile-flow and blocked-flow groups than in the continuous-flow group (550 +/- 106 vs 821 +/- 212 dynes/sec/cm-5). However, after blockade of endothelium-derived relaxing factor, resistances increased gradually in the blocked-flow group to reach the level of that of the continuous-flow group at the end of bypass (943 +/- 77 vs 556 +/- 143 dynes/sec/cm-5 in the pulsatile-flow group). CONCLUSIONS: Blockade of endothelium-derived relaxing factor after 30 minutes of pulsatile flow returns fetal hemodynamics to continuous flow conditions. The specific inhibitor of endothelium-derived relaxing factor used in this experiment suggests that nitric oxide may be released by fetal endothelium during pulsatile bypass.

Animals↗
PubMed1997

Mechanical valve in aortic position is a valid option in children and adolescents.

OBJECTIVE: The choice of a valve substitute remains a challenge in young patients, with numerous reports of early degeneration and calcification of biological valves in this age group. Therefore an assessment of the long-term results after mechanical aortic valve replacement in children was initiated. METHODS: A retrospective study was conducted in 54 consecutive patients aged 1.1 to 17 years (mean 12.8 +/- 4 years) operated on between 1975 and 1993. Aetiology was congenital in 34 patients, rheumatic in 13, infectious in 5, and dystrophic in 2. Concomitant surgery included mitral valve replacement (10), aortic annulus enlargement (9), correction of truncus arteriosus (7), Bentall operation (2), coarctation repair (2), tricuspid valvuloplasty (2), correction of double outlet right ventricle (1), and replacement of a right ventricle to pulmonary artery conduit (1). A Bjork-Shiley valve was implanted in 14 patients, and a St Jude Medical valve in 40. All patients were given Warfarin with a monthly INR control. Follow-up was completed through questionnaires mailed to referring physicians and direct clinical examination. RESULTS: Overall early mortality was 13% (7 cases), and 6% (2 cases) in the 32 patients operated on after 1984. Follow-up was complete in 45 survivors (2 lost to follow-up), with a total follow-up of 261 patient-years. There were 6 late deaths, 4 being cardiac and due to persistent LV dysfunction, and 2 valve-related, due respectively to major gastro-intestinal bleeding and massive thromboembolism. Linearized rates of valve thrombosis and anticoagulant-related hemorrhage were both 0.3% per patient-year. Actuarial survival rate was respectively 84.5% at 5 years and 70.2% at 10 years. Reoperation was necessary in 3 patients for recurrent LV outflow tract obstruction. One patient with severe LV dysfunction is awaiting a heart transplant. CONCLUSION: We conclude that the longterm outcome after mechanical aortic valve replacement in children and adolescents is satisfactory and comparable to currently available reports on biological substitutes. The mandatory anticoagulant therapy is well tolerated in this age group.

Adolescent↗
PubMed1997

Mechanical cardiac valve thrombosis in patients in critical hemodynamic compromise.

BACKGROUND: Valve obstruction is a life threatening complication of mechanical valve prosthesis. METHODS: From 1985 to 1993, 29 consecutive patients were hospitalized in our intensive care unit for mechanical prosthetic valve thrombosis (PVT). There were 12 men and 17 women aged 25-75 years (57 +/- 12). Prosthetic valve location was mitral in 14 patients, aortic in 6, aortic and mitral in 9. PVT occurred from 15 days to 174 months (67 +/- 52 months) after surgery. Delay from first symptoms to hospitalization ranged from 1 to 45 days (11 +/- 11). RESULTS: First clinical symptoms were progressive left heart failure in 17 patients, stroke in 6, and chest pain in 6. Furthermore, acute myocardial infarction was later documented in 3. Left heart failure NYHA III-IV was present in 26 patients (90%) on admission and 10 of those were in cardiogenic shock. Anticoagulation regimen was inadequate in 13 cases (45%). It has been recently stopped in 8 patients and incorrectly conducted in 5. Total hospital mortality was 41.3% (12). It was independent of type and position of the valve prosthesis. Diagnosis of PVT was only made at autopsy in 3 patients who died of recurrent myocardial infarction (2) or cardiogenic shock (1). Five further patients died before any surgery could be attempted (cardiac arrest: 2, cardiogenic shock: 3). Valve replacement could be done in 21 cases, 7 of whom were in cardiogenic shock and 9 had severe pulmonary edema. Four patients died after surgery, the operative mortality was 19%. CONCLUSION: PVT remains a serious complication of mechanical heart valve prostheses. Overall mortality rate is high, related to difficulty to diagnosis, delay to hospitalization and severe clinical condition at admission. In our study, operative risk remained acceptable even when the clinical presentation was severe.

Adult↗
PubMed1997

Malignant neoplasms following cardiac transplantation.

OBJECTIVE: Malignancies have long been recognized as a complication of long lasting immunosuppressive therapy. We reviewed our experience to investigate the incidence and the spectrum of non cutaneous de novo malignant neoplasms. METHODS: Between March 1987 and March 1996, 296 patients underwent 303 cardiac transplantation in our service. The population at risk consists of all patients surviving more than 1 month after transplantation, leading to a total of 267 patients. A triple-immunosuppressive therapy was employed. Moderate doses of antilymphocyte globulin was used as an induction immunotherapy. RESULTS: Neoplasms developed in 18 (6.7%) of the 267 patients at risk. Seventeen patients were male. Mean age was 56 +/- 7 years. Fourteen patients (78%) reported a significant smoking history. Mean interval between transplantation and clinical diagnosis was 36 months. Lung neoplasms (especially adenocarcinoma) were the most commonly encountered tumors (11 of 268 patients, 4.1%). Three Non-Hodgkins' Lymphoma (NHL) were identified (1.1%). No Kaposi's sarcoma were diagnosed. Mean survival after a diagnostic of tumor was 11.7 months. CONCLUSIONS: The incidence of NHL is low in our transplant recipients. Conversely, we observed a high incidence of lung neoplasms (especially adenocarcinoma) which can be correlated with a heavy cigarette use in the study population.

Adenocarcinoma↗
PubMed1997

[Left ventricular assistance by postoperative mechanical devices in neonates].

Circulatory assistance in children and neonates has not been extensively reported. It poses specific problems related mainly to miniaturisation of systems. The authors report three cases of left ventricular assistance with the Biomedicus centrifugal pump followed by functional recovery in neonates operated for d-transposition of the great arteries. The assistance was installed by cannulation of the left atrial appendage and the ascending aorta, the canules being connected to the Biomedicus pump. The duration of assistance was 53, 116 and 120 hours respectively. The beginning of left ventricular recovery was observed after 24, 48 and 70 hours of assistance and the patients were weaned of assistance under stable haemodynamic conditions. One of the major problems during the period of assistance is decoagulation, 2 out of 3 patients requiring removal of thrombi during the first 12 hours of assistance. On the other hand, no cases of systemic embolism or thrombosis in the pump itself were observed. Decoagulation was maintained by continuous intravenous heparin with an initial dosage of 5 U/kg/h adapted to the activated cephalin time and anti Xa levels measured every 6 hours. No infectious complication was observed and the sternal wound healed satisfactorily despite systematic delayed closure of the thorax. The quality of results requires cooperation of a surgical infrastructure used to techniques of circulatory assistance, a well equipped neonatal intensive care unit and a permanently accessible laboratory for monitoring coagulation status.

Cardiac Surgical Procedures↗
PubMed1997

[Coarctation of the aorta and its surgical treatment].

Coarctation or isthmic stenosis of the aorta is defined as an abnormal obstruction situated at the junction of the aortic arch and the descending aorta near the site of ligamentus arteriosus. It is a common malformation representing 5 to 7.5% of all congenital heart diseases. Coarctation of the aorta is 2 to 3 times commoner in boys than in girls. Two clinical forms may be distinguished: asymptomatic isolated coarctation of childhood, the surgical treatment of which was first performed by Crafoord in 1944, and coarctation of the neonate and infant associated in over 2/3 of cases with other cardiovascular malformations, especially tubular hypoplasia of the aortic arch. The surgical correction of isolated coarctation is best performed between 6 months and 1 year of age in other to limit the incidence of residual hypertension. A modified Crafoord technique decreases the risk of restenosis and enables treatment of associated hypoplasia of the aortic arch in the same surgical procedure.

Adult↗
PubMed1996

[Thrombolytic therapy with rt-PA of recurrent thrombosis in tricuspid valve prosthesis during pregnancy].

The authors report a case of a woman who had two episodes of a tricuspid Saint-Jude prosthesis thrombosis treated with fibrinolysis using rt-PA, during the fourth month of pregnancy. A first course of thrombolytic therapy was successful with normal valve function despite threatening abortion and uterine bleeding. An early rethrombosis of the prosthetic valve and a failure of a second course of thrombolysis required the interruption of pregnancy with a replacement of the tricuspid valve prosthesis.

Abortion, Therapeutic↗
PubMed1996

Long-term results of heart transplantation deteriorate more rapidly in patients over 60 years of age.

It is generally agreed that the upper age limit for heart transplantation is 60 years. However, an increasing number of elderly candidates are accepted for heart transplantation. We retrospectively analyzed our experience with a total of 204 consecutive transplantations, performed in 195 adult patients (9 retransplantations) between March 1987 and September 1993. There were 48 patients older than 60 years (mean 62.9 +/- 3), group I (gr I) and 156 patients between 20 and 59 years old (mean 47.5 +/- 8), group II (gr II). The two groups were matched for sex-ratio (female 10.4 vs 14.2%), indications (cardiomyopathy, ischemic, others), and hemodynamic parameters (pulmonary artery pressure, capillary wedge pressure, cardiac index). A ventricular assist device was used in 14 patients as bridge to transplantation in gr II vs 0 to gr I. There were seven early deaths in gr I (14.6%) vs 14 in gr II (8.97%, NS). A total of 183 survivors (41 vs 142) have been followed up for 1 month-6.3 years (mean follow-up 20.4 +/- 19.3 months in gr I, 35.4 +/- 23 in gr II). No patient was lost to follow-up. There were 11 late deaths in gr I vs 16 in gr II. The most common cause was malignancy (n = 4) in gr I and sudden death (n = 9) in gr II, with a significant difference. The actuarial survival was 68.8% in gr I vs 88.5% in gr II at 1 year 43.5% in gr I vs 76.4% in gr II at 5 years. In conclusion, transplanted patients over 60 years of age have a significantly poorer late survival than younger patients, despite similar good early results. Moreover, the causes of late deaths were different in the two groups. So, heart transplantation in patients over 60 years of age should be carefully considered.

Adult↗
PubMed1996

Primary melanoma of the heart: case report of an association with coronary stenosis.

A 63-year-old man presented with unstable angina. The coronary angiogram revealed a proximal left anterior descending artery (LAD) stenosis and an irregularity on the anterior wall of the left ventricle. Intraoperatively, a malignant melanoma, independent of the coronary stenosis, was identified and resected, and an internal mammary graft was inserted. No primary tumor was found. The patient is alive 18 months after operation, with a normal magnetic resonance imaging (MRI), which seems to be the technique of choice for following-up heart melanomas.

Coronary Disease↗
PubMed1996

[Hemodynamics of right circulation in ewes: normal values].

The right cardiac pressure was measured on 24 anesthetized adult ewes (Halothane) with a Swan Ganz catheter. After a review of the catheterization technique, the results (mean +/- standard deviation) in mmHg were: right auricle 17 +/- 5, right ventricle 30 +/- 6 (systolic) and 12 +/- 6 (telediastolic), pulmonary artery 29 +/- 6 (systolic), 13 +/- 6 (diastolic) and 20 +/- 6 (mean), capillary pressure 17 +/- 7. We observed slight variations in the pressure curve morphology compared to those found for man and the pressures were 5-10 mmHg higher than what is observed in man and slightly higher than those observed in dogs. These results also demonstrate a great variation between animals.

Anesthesia, General↗
PubMed1995

Formation and resolution of bilateral traumatic pulmonary pseudocysts.

A case of bilateral traumatic pulmonary pseudocysts, an uncommon complication of blunt chest trauma, is presented. The radiologic changes were followed over 6 months until spontaneous resolution had occurred. The mechanism of formation of traumatic pseudocysts and the diagnostic implications are discussed.

Adult↗
PubMed1995

[Thrombolytic therapy with rt-PA for thrombosis of tricuspid valve prosthesis during pregnancy].

The authors report the case of a woman with thrombosis of a tricuspid Saint Jude prosthesis during the fourth month of pregnancy. A first course of thrombolytic therapy with rt-PA reestablished normal prosthetic valve function but was followed by a threatened abortion and severe uterine haemorrhage. An early rethrombosis of the prosthetic valve led to interruption of the pregnancy after failure of a second course of thrombolysis, and to replacement of the tricuspid valve prosthesis. This case illustrates the problems of pregnancy in women with mechanical cardiac prosthetic valves and the difficulties of treatment.

Abortion, Therapeutic↗
PubMed1995

[Systematic transesophageal echocardiography during the postoperative first 24 hours after mitral valve replacement].

Systematic transoesophageal echocardiography after the 10th day of mitral valve replacement with a mechanical prosthesis has enable diagnosis of several abnormal conditions: thrombi, strands and paravalvular leaks. The aim of this prospective study was to determine the prevalence of these conditions by biplane transoesophageal echocardiography in the first 24 postoperative hours. Transthoracic and transoesophageal echocardiography was performed on average 12 +/- 3 hours after coming out of the surgical block in 77 consecutive patients who underwent mitral valve replacement with a mechanical prosthesis. Nine patients (11.7%) had appearances of thrombi or strands in the left atrium or auricle. These small thrombi (1 to 1.5 cm2) were not obstructive. No embolic events were observed in the first month of these patients. Spontaneous contrast was seen in the left atrium of 31 patients (40%). The factors associated with the presence of thrombus or strands were advanced age (p = 0.02), presence of spontaneous contrast (p = 0.02) and more dilated left atrium (p = NS) Paraprosthetic leaks were seen in 11 cases (14.3%). In 10 cases, the regurgitant jets were narrow at their origin with little extension into the left atrium. Only one patient had severe regurgitation associated with raised transprosthetic pressure gradients. Cases with paravalvular leaks had a lower incidence of spontaneous contrast (3.2% vs 21.7%) and no thrombosis. Transoesophageal echocardiography demonstrated spontaneous contrast, thrombi and strands in the initial hours following implantation of a mechanical mitral valve prosthesis. The prevalence of these appearances, comparable to that of the results reported with later investigations, underlines the importance of effective anticoagulation from the fist postoperative hours.

Aged↗
PubMed1994

[Post-infarction rupture of the heart into the pericardium. Surgical treatment combining synthetic patch and biological fibrin glue].

A 66-year old man was hospitalized with chest pain and acute ischaemia of the lower limbs highly suggestive of dissection of the aorta. Computed tomography and aortography however showed pericardic effusion and thrombosis situated in the iliac bifurcation of the aorta. During the emergency operation, acute tamponade required sub-xyphoid drainage. The haemodynamic situation was reestablished and the operation continued but within minutes a cataclysmal haemorrhage occurred through the drainage tube due to ischaemic rupture of the lateral wall of the heart into the pericardium. Extra-corporal circulation was installed immediately and a large polytetrafluoroethylene patch was sutured to the epicardium, distally from the necrosed area, in healthy tissue. A biological fibrin glue was injected under the patch. The operation was terminated with an axillo-bifemoral bypass. The postoperative period was satisfactory and the patient was discharged. At the six months examination, the patient was in NYHA class II and the echography showed moderate left ventricular dysfunction with grade II mitral regurgitation and a false aneurysm facing the area of necrosis. This technique allowed us to patch the rupture without excessive tension on the sutures in the fragile tissue which would have increased the risk of secondary rupture. In addition, the large patch avoided excessive reduction in volume of the left ventricular cavity and saved the mitral chordae which would have been destroyed by direct suture. This method can be an effective salvage technique for heart rupture during the acute phase of myocardial infarction and offers the possibility of a second look in case of a secondary false aneurysm.

Aged↗