Biomedical subjects

W Flameng

Publications and source records attributed to W Flameng.

280 records · Page 16Linked to original sources

PubMedDate not supplied

Differences in high-energy phosphate catabolism between the rat and the dog in a heart preservation model.

Concentrations of ATP and creatine phosphate were measured in rat and dog hearts preserved either by cold storage (procedure A) or by continuous hypothermic perfusion (procedure B). In procedure A (3 dogs, 4 rats) the hearts were normothermically excised without cardioplegia and were stored in 0.9% NaCl at 0.5 degrees C; in procedure B (6 dogs, 21 rats) hypothermic cardioplegic arrest was performed, and then the hearts were retrogradely perfused through the aorta for 24 hours with use of an oxygenated Bretschneider cardioplegic solution at 2 degrees to 4 degrees C. Whole rat hearts were frozen using Wollenberger clamps at desired times during the preservation period; transmural needle biopsy specimens were sampled from dog hearts. In control nonpreserved hearts, the ATP and creatine phosphate were as follows (mean +/- SD): 26.7 +/- 4.1 and 27.1 +/- 10.3 mumol/gm dry weight, respectively (dog hearts), and 23.1 +/- 2.1 and 34.2 +/- 12.1 mumol/gm dry weight, respectively (rat hearts). With procedure A, ATP decreased by 36% in dog hearts and by 64% in rat hearts during the first hour of storage. By 24 hours, only 6% of the ATP remained in the dog hearts and 1% in the rat hearts. Creatine phosphate decreased by 85% (dog hearts) and by 93% (rat hearts) during the first hour of storage. The ATP and creatine phosphate values observed in rat hearts after 1 hour of procedure A preservation were significantly lower than in dog hearts (p less than 0.05). With procedure B, cardioplegic arrest by itself did not alter high-energy phosphate concentrations in dog or rat hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗

PubMedDate not supplied

Long-term preservation of donor hearts: the effect of intra- and extracellular-type of cardioplegic solutions on myocardial high energy phosphate content.

The influence of cardioplegic arrest (single or multidose cardioplegia) and subsequent long-term cold storage on myocardial high energy phosphate content was studied in 29 dogs divided into 6 groups of experiments. Three cardioplegic solutions were tested: Bretschneider HTK (intracellular-type solution), St. Thomas' Hospital and N.I.H. solutions (both extracellular-type solutions). In group I, II and III single dose cardioplegic arrest with respectively St. Thomas' Hospital, Bretschneider HTK and N.I.H. solutions was carried out and excised hearts were stored at 0.5 degrees C for 24 hours. In group IV-Bretschneider HTK and in group V-N.I.H. solutions were used for cardioplegic arrest and intermittent perfusion of the cooled hearts at 4, 8 and 12 hours of storage (multidose cardioplegia). In group VI, after cardioplegic arrest with Bretschneider HTK solution, different temperatures of storage (0.5 degrees C, 12 degrees C and 18 degrees C) were studied. Myocardial content of ATP and creatine phosphate was evaluated by means of bioluminescence techniques from serial left ventricular biopsies taken prior to aortic cross-clamping and after 1, 2, 3, 4, 5, 6, 8, 10, 12 and 24 hours. In group I ATP was significantly lower than in groups II and III after 6 h (p less than 0.005). After 24 hours of storage ATP-levels were significantly higher (p less than 0.05) after multidose Bretschneider HTK cardioplegia or N.I.H. cardioplegia than after single dose N.I.H. or St. Thomas' cardioplegia. There was no significant difference in ATP content between multidose Bretschneider and multidose N.I.H. cardioplegia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗

PubMedDate not supplied

Successful orthotopic heart transplantation in dogs after 24 hours of continuous perfusion with Bretschneider HTK cardioplegic solution.

In 12 dogs the hearts after excision were perfused for 24 hours with Bretschneider HTK cardioplegic solution. Six of these hearts were used only to assess myocardial HEP and ultrastructure during 24 hours of conservation. In the next six dogs orthotopic heart transplantation was performed to evaluate functional outcome after prolonged preservation. After 24 hours of continuous perfusion of the donor heart the ATP level was completely comparable with control, preischemic value. Also ultrastructure of the myocytes was perfectly preserved. All transplanted hearts recovered completely upon reperfusion without a need of inotropic support. Good functional outcome after transplantation was correlated with about 70% of myocardial HEP content and intact ultrastructure of the myocytes. We concluded that continuous perfusion with Bretschneider HTK cardioplegic solution makes successful heart transplantation possible after 24 hours of preservation.

Animals↗

PubMedDate not supplied

Combined myocardial and cerebral revascularization. A ten year experience.

We report on the results of combined carotid endarterectomy and coronary artery bypass grafting in 82 patients. Vascular pathology was severe in these cases: 94% of patients had extensive multivessel coronary artery disease, 29% had unstable angina, 30% had severe left main stem stenosis and all patients had hemodynamically significant stenosis of at least one carotid artery, 13% had an additional occlusion of the contralateral internal or common carotid artery and 26% had severe bilateral carotid artery stenosis. The carotid lesion was asymptomatic in 64% of cases, 24% of the patients experienced previous transient cerebral ischemia and 12% of the patients had a history of completed stroke. Hospital mortality was 7.3%. Neurological deficit occurred in 7.3% but functional impairment was not permanent. Late results have been obtained for 76 survivors at a mean postoperative interval of 29 months. Five year life table survival rate was 86%. Follow-up showed that 3 patients (4%) have died and that 3 patients (4%) experienced a late neurologic event (one TIA; two strokes) but none of these events involved the cerebral cortex on the side of the carotid endarterectomy. The cumulative 5 year stroke free survival rate is 91%. We conclude that combined carotid endarterectomy and coronary artery bypass grafting can be done with an acceptable mortality rate in these critically ill patients and that the postoperative incidence of neurological events is low.

Adult↗

PubMedDate not supplied

The sequential internal mammary artery graft. Long term results of a consecutive series of 364 patients.

Sequential, bilateral and free mammary grafts are employed in the current operative treatment of coronary pathology to maximize the benefit of the enhanced long-term patency of the internal mammary graft. This study reports the early and late results of a consecutive series of 364 patients in whom an internal mammary artery jumpgraft was performed. The total perioperative mortality was 1.6%, the cardiac perioperative mortality 1.0%. The perioperative infarct rate was 2.5%; the infarct rate in the mammary outflow field 1.4%. The total survival at 90 months (operative mortality included) was 92.2%, the cardiac survival at 90 months was 95.8% and the event-free group of the operative survivors was 85.2% at 90 months. The mammary artery jumpgraft can be performed without additional risk to the patient, it has a very good late result and it should be standard tool in the current coronary surgery technique. It is essential in coronary redo surgery and in patients after bilateral saphenectomy.

Female↗

PubMedDate not supplied

Is the outcome of coronary artery bypass graft surgery predictable in patients with severe ventricular function impairment?

Sixty consecutive patients, with a mean ejection fraction of 31.8% underwent coronary revascularization at the K. U. Leuven (Belgium). The operative mortality was 6%. At twelve months after surgery, the total actuarial survival was 90.0%, at twenty four months the total survival was down to 77.9%. All the preoperative data were entered into a mathematical model and using the stepwise logistic regression method, the predictability of death at 18 months postoperatively was analyzed. Using only the ejection fraction the accuracy of the prediction was 83.3%, the sensitivity 36.4% and the specificity 93.9%. Combining ejection fraction and NYHA functional classification before surgery the accuracy increased to 91.7%, the sensitivity to 72.7% and the specificity to 95.9%. Ejection fraction alone is a poor predictor of late death with only 36.4% sensitivity, but combining it with other parameters it is possible to construct a formula predicting death at 18 months with an accuracy of 91.7%.

Actuarial Analysis↗

PubMedDate not supplied

Time constraints in the emergency coronary bypass surgery for acute evolving myocardial infarction.

Fourty four patients underwent emergency coronary grafting for evolving myocardial infarction. All patients but one had undergone coronary angiography before the new infarction, 50% were in cardiogenic shock or under cardiopulmonary resuscitation. The mean time interval between the onset symptoms and opening of the bypass to the threatened area was 171 minutes. The operative mortality was 6.8%. At 30 months after surgery, the cardiac actuarial survival was 93.2%, the angina free group 94.2% of the operative survivors. Infarct size and regional ejection fraction of these patients at late follow-up were compared to those of controls treated conventionally for acute infarction. The thallium defects were smaller and the regional ejection fraction of the involved segment was higher after early surgery (less than 3 hours ischemia) than in controls. In the late surgery group the thallium defects and the regional ejection fractions were similar. Ultrastructural studies on biopsy samples taken from the center of the threatened area show reversible changes in the early surgery group but irreversible mitochondrial damage and cell membrane rupture in the late surgery group. Biochemical analysis of similar cardiac biopsies shows recovery after one hour empty beating reperfusion but only in the early surgery group. Our results suggest that coronary surgery can be beneficial to the patient with an evolving myocardial infarction, if the clinical situation does not permit intracoronary thrombolysis. However, one hour reperfusion of the empty beating heart before weaning off bypass is essential. The time constraints for both emergency surgery or thrombolysis are similar.

Adult↗

PubMedDate not supplied

Surgical treatment of acute, massive lung embolism. Results and follow-up.

Between 1970 and 1984 the diagnosis of acute, massive lung embolism was made 30 times in our department. In 29 patients the clinical diagnosis was correct and a Trendelenburg operation under extra-corporeal circulation was performed. In 18 cases there was an operation in the immediate preoperative course. In 1 case there was a combination of operation and the use of contraceptives. 3 cases were immobilized by a plaster of Paris cast. In 4 cases the use of oral contraceptives and in 3 patients the history of chronic recurrent lung embolism were evident. The mean immobilisation time was 15 days. In 24 cases the diagnosis was made only on the base of the clinical anamnesis, and examination, E.C.G. and chest radiography. In 4 cases angiography and in 1 patient the scintigraphy confirmed the diagnosis. Preoperatively 28 patients were in severe shock. One patient was operated electively. 14 patients needed external cardiac massage. In all cases clots were found in the left pulmonary artery, 28 in the right pulmonary artery, in 3 cases clots in the right atrium, 3 in the right ventricle and three in the inferior caval vein. Nine De Weese caval vein clips were inserted and one Mobin-Uddin filter. Postoperatively 18 patients were alive and well without sequelae. Two patients developed a cerebro-vascular accident (CVA) with one complete recovery. Ten patients died. Postoperative treatment consisted of I.V. heparin administration immediately after surgery and 6 months of oral anticoagulants. Except for chronic recurrent lung embolism the pulmonary function tests were excellent postoperatively without recurrence of the disease.

Acute Disease↗

PubMedDate not supplied

Hemopump fails as bridge to transplantation in postinfarction ventricular septal defect.

From 1990, six patients were bridged to transplantation with a catheter-mounted axial flow pump (Hemopump). Indications were graft failure (two patients), postinfarction ventricular septal defect (two patients), myocarditis (1 patient), and myocardial infarction (1 patient). The 21F cannula, inserted via the groin, was used as a partial assist in four patients, and the 31F cannula, inserted via the ascending aorta, was used to assist the other two patients completely. Hemodynamic recovery was achieved in all patients (mean cardiac index rose from 2.1 L/gm/m2 to 3.85 L/gm/m2 after 1 hour assist). Sudden pump failure occurred in the two patients with postinfarction ventricular septal defect and a piece of necrotic tissue blocking the catheter was found. Both patients died. The other four patients were successfully bridged to transplantation. One of these patients died during his postoperative hospital stay; the three remaining patients were discharged and were well at follow-up (46, 40, and 3 months). The Hemopump device provides sufficient organ perfusion to be used as a bridge to transplantation. No conclusions can be drawn for the long-term use (longest run in this series was 102 hours). Postinfarction ventricular septal defect is a contraindication for the use of the Hemopump device.

Adolescent↗

PubMedDate not supplied

Effect of nucleoside transport inhibition on adenosine and hypoxanthine accumulation in the ischemic human myocardium.

The effect of nucleoside transport inhibition on the adenylate catabolism was studied in the human myocardium under normothermic ischemic conditions. Ten hearts from cardiac transplant recipients and two hearts from cardiac homograft donors were used in this study. The hearts were excised under hypothermic conditions (25 degrees C body temperature), the coronary arteries flushed with 500 ml ice-cold Ringer solution (n = 6; group I) or with ice-cold Ringer solution containing 1 mg/l of the nucleoside transport inhibitor R75231 (n = 6; group II). After transportation at 0 degree C from the operation room, the hearts were quickly rewarmed to 37 degrees C. Serial transmural biopsy specimens were taken during normothermic ischemia for determination of purine catabolites. The level of ATP before normothermic ischemia was 17.5 +/- 1.0 mumol/g dry weight in the control group (group I) and 19.3 +/- 0.4 mumol/g dry weight in the drug group. ATP, expressed as percentage of total purine content, was similar in both groups before rewarming (79.5 +/- 4.3% in group I and 79.5 +/- 2.9% in group II). There was no significant difference in the rate of ATP breakdown in both groups throughout the experiment (ATP was 3.0 +/- 1.4% of total purines in group I and 1.4 +/- 0.2% in group II at 120 min of normothermic ischemia). Adenine nucleotide content changed also similarly in both groups. Adenosine accumulation was, however, significantly higher in group II than in group I (peak values: 4.6 +/- 1.0% of total purines in group I vs 14.0 +/- 1.7% in group II; p < 0.01). The ratio between adenosine and inosine was significantly higher in group II throughout normothermic ischemia (p < 0.01). In spite of a larger accumulation of adenosine in group II, the increase in inosine was similar in both groups. We conclude that nucleoside transport inhibition significantly delays the breakdown of adenosine and the formation of hypoxanthine in the ischemic human myocardium.

Adenine↗