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Biomedical subjects

G Klingen

Publications and source records attributed to G Klingen.

13 recordsLinked to original sources
PubMed1990

Risk factors for morbidity and mortality in mitral valve replacement.

Risk factors of operative mortality and long term survival were identified in 219 patients who underwent mitral valve replacement (MVR) using Bjørk-Shiley mechanical prostheses. Early mortality was 7.3%. The accumulated follow-up time was 1134 patient-years, and the 5-year survival for the total cohort was 78 +/- 3%. Independent prognostic factors of early mortality were poor NYHA class, which carried a relative risk (RR) of 3.2, and ischaemic aetiology, with a RR of 2.2. Ischaemic aetiology was the sole predictor of heart pump failure requiring intra-aortic balloon pump support (RR = 2.7). Independent risk factors of total mortality (early and late) were male sex (RR = 2.3), NYHA class III-IV (RR = 2.4), presence of mitral regurgitation (RR = 3.2) and relative heart volume (RR = 1.6 for a 800 ml/m2 size compared to a heart of 550 ml/m2). Our results underline the importance of patient-related factors in MVR, and indicate that care is needed in comparing the quality of MVR from different institutions with respect to mortality and morbidity. The results of MVR are palliative rather than curative except in female patients with NYHA class II function and mitral stenosis, in whom cure was attained.

Adolescent↗
PubMed1989

Oxygen free radicals decrease survival time of isolated rat hearts.

Effects of oxygen free radicals (OFR), enzymatically generated in the coronary circulation, were studied in isolated rat hearts retrogradely perfused with Krebs-Ringer solution. Control hearts (n = 6) functioned adequately for at least 5 hours. When rat hearts (n = 6) received xanthine oxidase (XOD) and hypoxanthine (HX) in order to generate OFR, survival time was reduced to 31 +/- 0.4 min (mean +/- SEM). Infusion of XOD (n = 8) or HX (n = 5) alone also reduced cardiac survival time, to 32 +/- 6 min and 139 +/- 23 min, respectively. When allopurinol (an inhibitor of XOD) was given together with XOD (n = 6), survival time (277 +/- 30 min) was similar to the control value. The production of OFR did not result in depressed coronary flow or heart rate, but reduced the aortic pulse pressure. OFR thus can depress cardiac function and may ultimately cause cardiac arrest.

Animals↗
PubMed1989

Surgical treatment of left ventricular aneurysm. Analysis of risk factors, morbidity and mortality in 205 cases.

Left ventricular aneurysm was surgically treated in 205 patients during the decade 1975-1984. The patients had had one to five myocardial infarctions, the latest days to years (mean 32 months) preoperatively and 92% were in NYHA functional class III or IV. The main indications for surgery were angina (47%), congestive heart failure (38%) and arrhythmia (15%). The 176 anterior, 23 posterior and six combined aneurysms were treated with resection (130 cases) or plication (75). The early mortality was 5%. Univariate analysis identified arrhythmia, concomitant valve replacement and need for intra-aortic balloon pumping (IABP) as significant risk factors, and multivariate analysis revealed the indication for surgery and need for IABP as the only independent predictors of total mortality. The survival rates 5 and 10 years postoperatively were respectively, 74% and 60%. At follow-up after 1/2-10 years, almost 90% of the surviving patients had improved functional status. Left ventricular aneurysm thus can be surgically treated with low mortality rate and good functional result.

Adult↗
PubMed1985

Demonstration of an alpha adrenoceptor-mediated inotropic effect of norepinephrine in human atria.

It has been claimed by other investigators that norepinephrine does not evoke a significant alpha adrenergic inotropic effect in human atria in contrast to epinephrine and phenylephrine, indicating a limitation of a possible functional role of the cardiac alpha adrenoceptors. We therefore characterized the inotropic effects of norepinephrine in isometrically contracting muscle strips from human atria obtained during open heart surgery. Both contraction and relaxation were studied by measuring developed tension and its first and second derivatives. Both the influence of propranolol and prazosin upon the inotropic responses to norepinephrine and the qualitative characteristics of the responses revealed that norepinephrine evoked both alpha and beta adrenergic inotropic effects. The alpha adrenergic response to norepinephrine was qualitatively different from the beta adrenergic effect and qualitatively similar to the alpha adrenergic effect of norepinephrine observed in other mammalian species. Although the alpha adrenergic effect was marked, the beta adrenergic effect was the dominating one as has also been found in other species. It is concluded that also in human atria norepinephrine evokes inotropic effects through both alpha and beta adrenoceptors.

Heart Atria↗
PubMed1978

Circulatory adaptation after aortic valve replacement. A clinical study peroperatively and in the early postoperative period.

The myocardial function and the central and peripheral circulation were studied after aortic valve replacement. All patients showed a similar postoperative pattern of response. During the operation, after termination of bypass, the mean arterial blood pressure (Pa,m) was low. The total peripheral vascular resistance (TPR) and pulmonary vascular resistance (PVR) were normal. Immediately after the operation Pa,m, TPR and PVR were higher than peroperatively. The cardiac index (CI) and stroke index (SI) were low, and the heart rate (HR) was high. At this stage the oesophageal temperature was increasing, but there was no shivering. Then followed a period in which Pa,m and TPR decreased, while CI and SI remained essentially unchanged. The oesophageal temperature reached its highest value 5 hours postoperatively. Peripheral warming began in the 3rd hour postoperatively and was completed in the 6th hour, when the peripheral temperature was 35 degrees C. The progressive peripheral warming, with peripheral cutaneous vasodilatation and slight reduction of the heart rate, took place without signs of increasing CI or SI. The left and right ventricular function, expressed as the relation between LVSWI and Pla,m, and RVSWI and Pra,m, respectively, varied postoperatively and showed no signs of improvement at the time of peripheral warming. Cardiac output and myocardial function seemed to be little affected by the obvious changes appearing during the systemic and peripheral vasodilatation in connection with central and peripheral warming.

Aged↗
PubMed1978

Haemodynamic effects of ethanol immediately after aortic valve replacement. A clinical study peroperatively and in the early postoperative period.

The haemodynamic effects of intravenous (i.v.) administration of ethanol were studied in two groups of patients--groups IV and V--during the first hours after aortic valve replacement. A group of seven patients, who underwent the same operation but were not treated with ethanol, served as controls (Klingen et al., 1978 c). The ethanol was given by continuous i.v. infusion. It was started after termination of bypass and was continued for 6 hours postoperatively. Group IV (9 patients) had a blood concentration of about 20 mmol/l. Group V (8 patients) had a blood concentration constant at 35-40 mmol/l. Groups IV and V differed from group III in their reactions in the following respects, and the differences may be attributed to the ethanol. In the former groups the arterial (systemic) blood pressure and total peripheral vascular resistance were lower (P less than 0.01 and P less than 0.001, respectively). Cardiac output was higher (P less than 0.05) and the arteriovenous oxygen difference lower (P less than 0.01) in group IV and V and increased at an early stage (P less than 0.01). The study shows that ethanol in blood concentrations of 20 and 35-40 mmol/l has approximately the same vasodilative effect, with no influence on the heart rate and no depressive effect on myocardial function; on the contrary this function tended to be stimulated at a blood concentration of 35-40 mmol/l.

Adult↗
PubMed1977

Transcervical thymectomy with the aid of mediastinoscopy for myasthenia gravis: eight years' experience.

Fifty-eight patients with myasthenia gravis, including 12 children, underwent thymectomy. Eleven of them (19%) had total stable remission and 42 (72%) showed clinical improvement and were able to reduce their anticholinesterase medication. These two groups combined comprised 53 patients (91%). There was no operative or postoperative mortality. Histopathological examination of the resected thymuses revealed a tumor (benign thymoma) in 4 patients (7%), thymitis in 36(62%), and no pathological changes in 18(31%). Patients with few or no germinal centers tended to achieve remission more rapidly than those with numerous germinal centers.

Adolescent↗