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Biomedical subjects

W Daenen

Publications and source records attributed to W Daenen.

At least 91 records · Page 5Linked to original sources
PubMed1985

Pacing in children.

Fourteen children had a permanent pacemaker implanted between May 1967 and July 1983. Postoperative complete heart block was the indication in nine cases, congenital complete heart block in three, and sick sinus syndrome in two. Two patients died, one suddenly and one after aortic valve replacement. A total of 48 pulse generators were implanted; five patients were given an isotopic pacemaker. Twelve patients had epicardial leads implanted initially, and two received a transvenous endocardial system. The lead system implanted initially remained without malfunction in only seven patients. In the other seven patients 20 lead malfunctions occurred. Psychological maturity and physical development seemed to be normal in all 14 children. Improvement in equipment and technique will improve the outlook for paced children in the future.

Cardiac Pacing, Artificial↗
PubMed1983

Nine years' experience with the Björk-Shiley prosthetic valve: early and late results of 932 valve replacements.

Between November, 1970, and December, 1977, 932 consecutive patients received the standard Björk-Shiley prosthesis. Operative mortality was 4.6% for aortic valve replacement (AVR; N = 364), 5.1% for mitral valve replacement (MVR; N = 313); 11.3% for multiple valve replacement (N = 194), and 13.7% for valve replacement combined with coronary artery bypass grafting (CABG; N = 51). Factors influencing hospital mortality included type of valve replacement, age at operation, whether the valve replacement was done as an emergency, and year of implantation. Complete follow-up (mean, 3.7 years) was achieved in 95% of the survivors. Actuarial survival was 82% for AVR patients at 8 years, 83% for MVR patients at 7 years, 72% for multiple valve replacement patients at 7 years, and 76% for those who had valve replacement with CABG at 3 years. No significant difference in late survival was found between patients with mitral insufficiency alone (p greater than 0.2) or aortic insufficiency alone (p greater than 0.9) and those with stenotic lesions only. Thromboembolic complications occurred at an incidence of 1.17% per patient-year, and Dicumarol-induced hemorrhages occurred at an incidence of 2.11% per patient-year. Twelve out of 13 patients survived operation for prosthetic valve thrombosis, indicating that this complication is not as catastrophic as many believe. The incidence of reoperation in anticoagulated patients was 0.63% per patient-year. All of these results are compared with data from the recent literature.

Aged↗
PubMed1981

St. Thomas cardioplegia versus topical cooling: ultrastructural and biochemical studies in humans.

Transmural left ventricular biopsies were studied from 28 patients undergoing cardiopulmonary bypass with anoxic cardiac arrest. The myocardium was protected by topical cooling (20 degrees C) (Group 1, 15 patients) or by cardioplegia with St. Thomas' solution (Group 2, 13 patients). Biopsies were taken at the start of bypass and 3 to 5 minutes after unclamping of the aorta. Mean cross-clamp time was not significantly different between the groups (50 minutes for Group 1 and 53 minutes for Group 2; p greater than 0.05). The ultrastructural changes induced by ischemia and subsequent reperfusion were almost exclusively related to the mitochondria. The degree of mitochondrial damage was evaluated by a semiquantitative analysis based on mitochondrial fine structure. The frequency of severe postischemic mitochondrial damage was significantly higher in Group 1 (20.1% versus 2.7% in Group 2; p less than 0.05). Biochemical analysis of the biopsies indicates that the myocardial concentration of creatine phosphate decreases by about 50% after topical cooling (p less than 0.05). With St. Thomas cardioplegia, no significant change in the tissue level of this high-energy phosphate takes place. The results show evidence of the superiority of the St. Thomas cardioplegia to topical cooling alone.

Adult↗
PubMed1981

Cardioprotective effects of lidoflazine during 1-hour normothermic global ischemia.

The cardioprotective effects of lidoflazine, a drug with calcium homeostatic properties, were investigated in dogs subjected to 1 hour of normothermic global ischemia, followed by reperfusion. None of the eight control dogs could be weaned from the extracorporeal bypass, confirming the severity of the ischemic model. All eight acutely pretreated dogs showed rapid recovery from the prolonged ischemic arrest and could support their own circulation. Recovery of preischemic values was 95% for systolic aortic pressure, 71% for diastolic aortic pressure, 99% for left ventricular dP/dt max and 80% for cardiac output. Light and electron microscopy and calcium cytochemistry were performed on left ventricular biopsies taken before, during and after ischemic arrest. In the control dogs, loss of structural integrity of the sarcolemma and mitochondria was prominent at the end of the ischemic period. Intracellular edema, hypercontraction of sarcomeres and great accumulation of calcium in severely damaged mitochondria occurred after 5 and 30 minutes of reperfusion. In the lidoflazine-treated dogs, such lesions were largely prevented during the ischemic period and completely reversed after reperfusion. These observations suggest that the tolerance of ischemia is markedly augmented by lidoflazine.

Animals↗
PubMed1981

Myocardial protection by lidoflazine during one-hour normothermic global ischemia.

The cardioprotective effects of lidoflazine, a drug with calcium homeostatic properties, were studied in 12 dogs (6 drug-treated and 6 controls) subjected to 1-hour normothermic global ischemia. None of the control dogs could be weaned from the extracorporeal bypass after 30 minutes of reperfusion. In contrast, all acutely pre-treated animals were able to support their own circulation. Recovery of pre-ischemic values in this group was 97 +/- 3% for systolic aortic pressure, 69 +/- 7% for diastolic aortic pressure, 97 +/- 10% for left ventricular pressure, and 84 +/- 11% for cardiac output. Electron microscopy and calcium cytochemistry were done on left ventricular biopsies taken before, during, and after ischemic arrest. In the control group, severe damage to the sarcolemma and the mitochondria was found at the end of the ischemic period and became more prominent after 5 and 30 minutes of reperfusion. There was great accumulation of calcium in the damaged mitochondria. In the lidoflazine-treated dogs, these lesions were largely prevented. These findings suggest a strong cardioprotective effect of lidoflazine during severe myocardial ischemia.

Animals↗
PubMed1980

Ultrastructural and cytochemical correlates of myocardial protection by cardiac hypothermia in man.

We report observations on ultrastructural and cytochemical changes in the myocardium after hypothermic protection in 21 patients who underwent cardiac operation. Two general categories of hypothermic protection were studied. (1) topical cooling during anoxic arrest and moderate general hypothermia (10 patients with aortic valve replacement, Group 1) and (2) intermittent perfusion during moderate general hypothermia combined with topical cooling (11 patients with multiple valve replacement, Group II). Transmural left ventricular biopsies were taken at the start of the cardiopulmonary bypass and shortly after the end of aortic cross-clamping. In Group I (cross-clamp time, 51 +/- 12 minutes) only minor pathologic changes of the myocardial fine structure were found, with no differences among the left ventricular layers. In most mitochondria, structure remained intact but the mitochondrial granules disappeared. Cytochrome-c-oxidase activity was unchanged. In Group II (total cross-clamp time, 83 +/- 16 minutes) the subendocardium was well preserved. Slight subcellular damage comparable with that of resulting from topical cooling was seen in all hearts even after a total cross-clamp period of 106 minutes. Cytochrome-c-oxidase activity was unchanged. In the subepicardium, however, a positive correlation was found between the severity of ultrastructural damage and total cross-clamp time (p less than 0.05). Matrix clearing, damage to the cristae and the mitochondrial membranes, and nuclear abnormalities occurred when the aorta was cross-clamped for morethan 60 minutes. Cytochrome-c-oxidase activities decreased in these samples. It is concluded that: (1) no significant subcellular injury was found in hearts cooled topically during 1 hour of anoxic arrest; and (2) in hearts protected by intermittent perfusion during moderate general hypothermia and additional external cooling, the subendocardium was well preserved for anoxic periods of up to 106 minutes. However, after 60 minutes of aortic cross-clamping subcellular damage increased progressively in the subepicardium.

Aged↗
PubMed1980

Aortofemoral grafting: factors influencing late results.

During a 15-year period, the aortofemoral Dacron graft was used for revascularization of 615 limbs in 352 patients, with an overall operative mortality rate of 5.1% and a cumulative 10-year patency rate of 62%. The late complication rate was 27%, with late thrombosis being by far the most frequent complication (24%). Among several factors responsible for late occlusion, the presence of trifurcation disease and the site of the femoral anastomosis are by far the most important. Our procedure of choice for a thrombosed graft limb is thrombectomy and profundaplasty, which give a long-term patency rate of 68%.

Adult↗
PubMed1979

Aneurysm of the left atrial appendage.

A 2-year old asymptomatic girl is presented in whom the chest x-ray film led to the discovery of a grossly distorted cardiac shadow. Angiocardiography showed a giant aneurysm originating from the left atrium. At operation an intrapericardial aneurysm of the left atrial appendage, measuring 12 X 4 X 4 cm, was found. It communicated with the left atrium through an orifice measuring 3 cm. The aneurysm was excised.

Angiography↗
PubMed1975

[The tetralogy of Fallot: surgical treatment. 145 cases (author's transl)].

1. The overall operative risk for the palliative procedures for Tetralogy was 3,2% (93 cases). The Blalock-Taussig shunt remains the intervention of choice in older children. The Waterston shunt gives optimal results in the infants under six months of age but on long term the hasard of pulmonary hypertension still exists. 2. Before 1965, the mortality rate for the total repair was 43,7% (16 cases). During the last 8 years, the mortality rate decreased to 5,7% (36 cases). One operative death after total correction with a Potts shunt is not included in this figure. This type of shunt was replaced by the Waterston shunt after 1966, because of the high operative risk total correction and the high frequency of pulmonary hypertension on long term. 3. The long-term results were excellent in 85% of the survivors (mean follow-up of 4,1 years). A pulmonary insufficiency was found on clinical examination in 35% of the cases. This insufficiency was well tolerated by all patients. The long-term consequences, however, are uncertain. 4. It seams rational to proceed to an earlier total correction in these cases when well defined criteria are fullfilled, as the mortality figures of the palliative and corrective procedures have a tendency to reach each other: (3,2 versus 5,7%).

Aorta↗