Biomedical subjects

P Van Cauwelaert

Publications and source records attributed to P Van Cauwelaert.

11 recordsLinked to original sources

PubMed2003

Adding lactate to the prime solution during hypothermic cardiopulmonary bypass: a quantitative acid-base analysis.

BACKGROUND: The effect of adding lactate to the cardiopulmonary bypass (CPB) prime was investigated using Stewart's quantitative acid-base approach. According to this quantitative model, serum pH and bicarbonate are determined by three independent factors: the partial pressure of carbon dioxide (PCO(2)), the total concentration of weak acids (e.g. albumin), and the strong ion difference. The apparent strong ion difference is calculated as the sum of sodium, potassium, magnesium and calcium minus chloride concentrations. The pH decreases with a smaller strong ion difference and vice versa. METHODS: Twenty patients scheduled for coronary surgery were studied prospectively. All patients were treated identically, except for the prime, which either contained lactate or was lactate free. Just before bypass and before coming off bypass, haemoglobin, glucose, plasma osmolality and colloid osmotic pressure were determined; albumin, lactate, sodium, potassium, ionized calcium, magnesium, phosphate, arterial pH, PCO(2), bicarbonate, and base excess were measured for use in Stewart's analysis. RESULTS: Metabolic acidosis had resolved by the end of bypass with the lactated prime. Although the strong ion gap (apparent minus effective strong ion difference) increased significantly in both groups, its composition differed significantly between the groups. The Stewart technique detected polyanionic gelatin as a weak acid component contributing to the unidentified anion fraction. Colloid osmotic pressure was maintained in both groups. CONCLUSION: Exogenous lactate attenuates acidosis related to CPB. The oncotic and weak acid deficits produced by hypoalbuminaemia may be compensated for temporarily during CPB by polyanionic synthetic colloids such as succinylated gelatin.

Acid-Base Equilibrium↗

PubMed2001

Determinants of survival after aortic valve replacement as treatment for symptomatic aortic valve disease in the elderly.

BACKGROUND AND AIM OF THE STUDY: The effect of concurrent disease and cardiac comorbidity on survival after bioprosthetic valve replacement in elderly patients was assessed retrospectively. Risk factors were categorized as general, non-cardiac (age, diabetes, previously treated carcinoma) and cardiac (LVEF, three-vessel disease, previous CABG or valve replacement, and endocarditis). METHODS: A total of 400 elderly patients (median age 73 years; range: 71-76 years) was studied. Medical history included diabetes, previous CABG or aortic valve replacement (AVR), endocarditis and treatment of previous carcinoma. A left ventricular ejection fraction (LVEF) of <0.66 and presence of three-vessel disease were also investigated. Hospital deaths (and cause) were recorded; survival or date and cause of death after discharge were obtained by questionnaire. Kaplan-Meier univariate and Cox proportional hazards multivariate regression analyses were carried out. RESULTS: Mortality during follow up was 28.3%; hospital mortality was 3.8%. Univariate analysis showed five factors significantly to affect survival: LVEF, history of endocarditis, carcinoma, age and three-vessel disease. Fifteen of 38 patients with history of carcinoma died, 10 due to a malignancy. Of 76 patients with three-vessel disease, 26 died. A history of diabetes and previous CABG did not influence survival significantly. Four of eight patients with preoperative endocarditis died, all in hospital. Six of 11 patients died after redo-AVR, none before 36 months follow up. By Cox regression analysis, LVEF and histories of carcinoma and endocarditis remained significant. CONCLUSION: AVR should be performed before ventricular deterioration occurs. Previous CABG is not a contraindication for AVR. Endocarditis impaired survival. Long-term mortality after redo-AVR in this population was relatively high, but acceptable. AVR should also be performed in elderly patients with aortic valve disease. Since prognosis of symptomatic aortic valve disease is poor in the short term, AVR is indicated in patients treated for carcinoma.

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PubMed2000

High-level transgene expression in primary human T lymphocytes and adult bone marrow CD34+ cells via electroporation-mediated gene delivery.

The design of effective gene delivery systems for gene transfer in primary human blood cells is important both for fundamental hematopoiesis research and for cancer gene therapy strategies. Here, we evaluated electroporation as a nonviral means for transfection of activated human T lymphocytes and adult bone marrow (BM) CD34+ cells. We describe optimal culture and electroporation parameters for efficient gene delivery in prestimulated T lymphocytes (16.3 +/-1.3%), as well as 2-day cultured adult BM CD34+ cells (29.6+/-4.6%). PHA-stimulated T cells were most receptive for transfection after 48h of in vitro culture, while T cells stimulated by CD3 cross-linking and interleukin (IL)-2 achieved maximum transfection levels after 72 h of prestimulation. Kinetic analysis of EGFP expression revealed that activated T lymphocytes maintained transgene expression at high levels for a prolonged period. In addition, fresh unstimulated BM CD34+ cells were consistently transfected (5.2+/-0.4%) with minimal cytotoxicity (<5%), even without preliminary CD34+ cell purification. Both T cells and CD34+ cells retained their phenotype and functional capacity after electroporation. These results demonstrate that electroporation is a suitable nonviral transfection technique that may serve applications in gene therapy protocols using T lymphocytes or CD34+ cells.

Adult↗

PubMed1999

Developmentally regulated responsiveness to transforming growth factor-beta is correlated with functional differences between human adult and fetal primitive hematopoietic progenitor cells.

Important functional differences exist between primitive CD34++ CD38- hematopoietic progenitor cells derived from human fetal liver (FL) and adult bone marrow (ABM). FL progenitors are known to have higher proliferative capacities and lower cytokine requirements than their ABM counterparts. In this study, we isolated FL and ABM CD34++ CD38- cells and used a two-stage culture system to investigate the effects of transforming growth factor-beta (TGF-beta) and blocking anti-TGF-beta antibodies (anti-TGF-beta) on these cells. First, we demonstrate that FL progenitors are significantly less sensitive to the inhibitory effects of TGF-beta than ABM cells. Second, whereas ABM cells are significantly stimulated by anti-TGF-beta, only very limited effects are seen on FL cells. Third, we show that the effect of anti-TGF-beta is mainly situated at the level of the initial cell cycles of very primitive progenitor cells with a high proliferation potential. Fourth, we demonstrate that blocking the effects of endogenous TGF-beta reduces the growth factor requirements of ABM cells in order to proliferate and differentiate. Based on these data, we hypothesize that at least part of the functional differences that exist between adult and fetal stem cells can be accounted for by a developmental different responsiveness to TGF-beta.

Adult↗

PubMed1997

Haptoglobin polymorphism, a genetic risk factor in coronary artery bypass surgery.

Haptoglobin (Hp) 2-2 type has been associated with accumulation of atherosclerotic lesions in essential hypertension. The aim of this study was to investigate the relationship between Hp type and the extension of coronary lesions in 765 male patients who underwent coronary artery bypass grafting (CABG). In this group, relative Hp1 (0.418) and Hp2 (0.582) allele frequencies were comparable with those of the reference population. Candidate CABG patients with a Hp 2-2 type were overrepresented in the younger (< 45 years) age group (P < 0.05). Hp 2-2 patients needed more bypass grafts than Hp 1-1 patients (relative risk 1.92 95% C.I. 1.24-2.96). The Hp 2-2 type was overrepresented among victims of a previous acute myocardial infarction (P < 0.05) and among patients with a lower (< 45 years) age at infarction (P < 0.05). In patients who already underwent a previous CABG graft survival time was shortest in Hp 2-2 type (P < 0.05). Patients with a Hp 2-2 type more likely develop atherosclerotic lesions despite comparable serum lipid concentrations.

Adult↗

PubMed1996

Clinical evaluation of the oxygenation capacity and controllability of 15 commercially available membrane oxygenators during alpha-stat regulated hypothermic cardiopulmonary bypass.

Oxygenation performance was tested in 15 membrane oxygenators by calculating the resistance for oxygenation (R) and the calculation of oxygen transferred versus FiO2. The clinical data reveal that the SARNS Turbo 440 (36.7-51.9%), the AFFINITY (37.2-50.1%) and the HF 5400 (37.5-52.3%) are the oxygenators with the lowest FiO2 settings for comparable amounts of oxygen transferred during hypothermia and during normothermia followed by MAXIMA Plus (39.1-55.8%), MAXIMA Plus PRF (39.1-56.2%), CAPIOX SX 18 (39.7-61.2%), MONOLYTH (43.0-61.3%), OXIM 11-34 (44.1-63.9%), COBE Duo (44.7-64.9%), COBE Optima (47.4-66.4%), COMPACTFLO (48.3-65.3%), SAFE II (49.0-67.6%), UNIVOX (49.8-71.3%), MAXIMA (50.2-70.1%) and the CM 50 (58.6-77.0%). Similar results were found by calculation of R. HF 5400 (2.41-1.87 mmHg/min/ml O2), AFFINITY (2.63-1.87 mmHg/min/ml O2). OXIM II-34 (2.72-2.45 mmHg/min/ml O2), MAXIMA Plus PRF (2.75-2.07 mmHg/min/ ml O2), COBE Optima (2.83-2.13 mmHg/min/ml O2), UNIVOX (2.84-2.17 mmHg/min/ml O2), MONOLYTH (2.89-2.24 mmHg/min/ml O2), SARNS Turbo 440 (3.03-2.12 mmHg/min/ml O2), MAXIMA Plus (3.09-2.28 mmHg/min/ml O2), SAFE 11 (3.19-2.50 mmHg/min/ml O2), CAPIOX SX 18 (3.27-2.44 mmHg/ min/ml O2), COMPACTFLO (3.41-2.50 mmHg/min/ml O2), MAXIMA (3.53-2.72 mmHg/min/ml O2), COBE Duo (3.57-2.71 mmHg/min/ml O2) and the CM 50 (3.53-2.72 mmHg/min/ml O2). As a measure of controllability of oxygenation, the coefficient of variation on the FiO2 ordered on the normothermic blood samples was used, giving as a result CAPIOX SX 18 (2.9-2.5%), AFFINITY (3.6-3.5%), COBE Duo (4.3-2.9%), HF 5400 (5.7-4.7%), MAXIMA Plus (8.1-5.4%), COMPACTFLO (8.2-5.0%), MONOLYTH (8.3-4.0%), MAXIMA (8.7-3.4%), COBE Optima (9.6-6.8%), SARNS Turbo 440 (10.1-7.3%), MAXIMA Plus PRF (10.9-8.7%), CM 50 (11.9-2.4%), UNIVOX (13.3-8.9%), OXIM 11-34 (15.5-17.3%) and the SAFE II (16.1-9.8%). The low FiO2 settings and the lower resistance for oxygenation are an indication of the reserve capacity of the oxygenators whose importance is proven by clinical data of emergency perfusions on patients under full resuscitation.

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PubMed1991

Priming solutions for cardiopulmonary bypass: comparison of three colloids.

The present study was designed to compare the differences in the clinical effects of three colloidal solutions, albumin, urea-linked gelatin, and succinyl-linked gelatin, when used as priming fluids for cardiopulmonary bypass (CPB) under alpha-stat conditions. A consecutive series of 105 patients scheduled for cardiac surgery were randomized into three identically managed groups, except for the CPB prime. Variables relating to acid-base status, oncotic activity, metabolism, coagulation, and postoperative evaluation were measured. Marked differences in acid-base status, colloid osmotic pressure, additional prime requirements, blood lactate, urine output, and the need for buffer solutions occurred among groups, with the succinyl-linked gelatin group having better results than the other groups. Changes in hemodynamics, oxygen consumption, and blood-glucose levels during CPB did not vary among groups. There were also no important intergroup differences in hematologic and clotting variables or postoperative parameters such as blood loss or use of blood products. Electrolyte changes were similar except for a significant increase in ionized calcium that occurred in the urea-linked gelatin group after bypass. The results indicate that succinyl-linked gelatin is an adequate and safe alternative to human albumin for use as a colloid during CPB under alpha-stat conditions.

Acid-Base Equilibrium↗

PubMed1991

Predictive value of coagulation testing in cardiopulmonary bypass surgery.

Severe postoperative bleeding in cardiopulmonary bypass surgery is still a major problem. One hundred and seven patients undergoing uncomplicated coronary artery bypass grafting (CABG) were studied. Two groups were formed according to the patients' 24 hours postoperative mediastinal blood loss. Patients in group I (n = 70) had blood loss less than 1000 ml and patients in group II (n = 33) had blood loss over 1000 ml. Between the two groups, there were no differences in age, male-female ratio, number of grafts, by pass-time or heparin-protamine dose. Coagulation testing: APTT (Activated Partial Thromboplastin Time), PT (Prothrombin Time), fibrinogen, D-dim. (D-dimers), bleeding time, MPV (mean platelet volume) and platelet count, was done preoperatively (T0), immediately postoperatively (T1), 6 hours postoperatively (T2). We were especially interested in the predictive value of hemostatic parameters at T0 and T1. We found a slight but statistically negative correlation between the platelet count (T0 and T1) and the postoperative blood loss.

Blood Coagulation Tests↗

PubMed1978

Experience with lymphangioma.

Lymphangioma is a rare and benign tumor, mostly encountered in childhood. Our experience extends to 21 patients, all of which were operated upon. Early radical excision in moderate forms or cervical locations and delayed excision or combined management in complex cervical forms are the more preferable way of treatment.

Abdominal Neoplasms↗

PubMedDate not supplied

Timing of aortic valve replacement in elderly patients with symptomatic aortic valve disease using outpatient clinical parameters.

OBJECTIVE: To determine by how far worsening outpatient clinical parameters can affect outcome after aortic valve replacement, in patients with preserved left ventricular function and symptomatic aortic valve disease. PATIENTS AND METHODS: Five hundred patients with aortic valve disease underwent aortic valve replacement using a bioprosthesis. In 348 patients, another procedure was added. The preoperative outpatient parameters were investigated for their effect on hospital and long-term mortality. A Fisher exact, Kaplan-Meier univariate and Cox proportional hazard analysis were used. RESULTS: A retrospective follow-up of 2022 patient years was obtained. Five preoperative parameters were found to be more present in patients with a decreased left ventricular function: 1) severity of symptoms, 2) previous myocardial infarction, 3) conduction defects, 4) aortic valve regurgitation and 5) increasing need for medication. In patients with an ejection fraction of 50% or more, logistic regression analysis showed that hospital mortality increased with need for medication (p=0.004), previously performed CABG (0.015), increase in symptoms (p=0.018) and myocardial infarction (p=0.034). A Kaplan-Meier analysis revealed aortic valve regurgitation (p=0.017) and increased need for medication (p=0.012) as significant on long-term survival. Presence of a previous myocardial infarction showed a trend (p=0.062). A Cox' proportional hazard analysis showed for global mortality increased need for medication (p=0.010) and previous myocardial infarction (p=0.018) as independent factors and for long-term mortality, this was aortic valve regurgitation (p=0.001). CONCLUSIONS: Results after aortic valve replacement deteriorate with the presence of valve regurgitation, a preoperative myocardial infarction, increasing need for medication or severity of symptoms, even for an ejection fraction of 50% or more. Anamnesis with special care to the degree of symptoms and increasing need for medication early in the valve disease could lead to early referral, thereby reducing number of patients with severe symptoms and improving postoperative results.

Age Factors↗

PubMedDate not supplied

The cerebro-vascular problem in coronary by-pass surgery.

In 99 of 2250 consecutive C.B.P. cases, signs of cerebro-vascular disease (C.V.D.) were recorded in 87 (3.9%) on admission and in 12 post-operatively. The detection of C.V.D. by auscultation alone is very incomplete. There were 17 post-C.B.P. neurologic deficits (P.O.N.D.) (0.75%): 15 strokes (0.67%) and 2 T.I.A.'s. 26 patients (out of 87 detected on admission) were treated by carotid endarterectomy (C.E.) either pre-by-pass or simultaneously. There were no complications. The remaining 61 patients, who were not treated, had 4 strokes and 1 T.I.A. after their C.B.P. The most probable cause of these deficits was pre-existing C.V.D. Could more extensive pre-operative investigation, and treating the serious lesions by C.E., improve the P.O.N.D. incidence? The published series on simultaneous C.E. + C.B.P. are not yet conclusive. We favour C.E. done before the C.P.B. procedure except in very serious coronary disease when simultaneous operation is preferred.

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