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Biomedical subjects

K E Sørensen

Publications and source records attributed to K E Sørensen.

At least 19 recordsLinked to original sources
PubMed2004

Maternal hyperglycemia improves fetal cardiac function during tachycardia-induced heart failure in pigs.

BACKGROUND: Fetal tachycardia often leads to cardiac failure, which in experimental settings can be prevented by direct fetal glucose-insulin administration. In this study, we hypothesize that similar effects can be obtained indirectly by inducing maternal hyperglycemia. METHODS AND RESULTS: Systolic and diastolic indices (dP/dt(max) and tau) of left ventricular function were measured by use of high-fidelity catheters during 180 minutes of aggressive atrial pacing ( approximately 300 bpm) in 12 preterm porcine fetuses. In 6 fetuses, maternal hyperglycemia (15 mmol/L) was induced for the last 120 minutes of pacing. The remaining fetuses served as controls. Glucose, insulin, and free fatty acid levels were determined, as was fetal myocardial glycogen content. Maternal glucose infusion led to significant fetal hyperglycemia and hyperinsulinemia but did not change the inherently low fetal levels of free fatty acids. There were no differences between groups with regard to dP/dt(max) (1025+/-226 and 1037+/-207 mm Hg, P=NS) and tau (20.6+/-2.0 and 21.4+/-1.6 ms, P=NS) at baseline (100%). During the 180 minutes of pacing, systolic function (dP/dt(max)) and diastolic function (tau) deteriorated more in the control group than in the hyperglycemic group (P<0.001 for both). At 180 minutes, dP/dt(max) was 62+/-18% of baseline in controls and 85+/-11% in hyperglycemic fetuses (P=0.03), and tau was 117+/-12% and 98+/-4%, respectively (P=0.004). CONCLUSIONS: Induced maternal hyperglycemia improves fetal cardiac function during fetal tachycardia and suggests a possible additional therapeutic option to improve the function of the failing fetal heart before or during antiarrhythmic therapy. The findings may be relevant in fetal heart failure in general.

Animals↗
PubMed2002

Flow during exercise in the total cavopulmonary connection measured by magnetic resonance velocity mapping.

OBJECTIVE: To measure caval and pulmonary flows at rest and immediately after exercise in patients with total cavopulmonary connection (TCPC). DESIGN: An observational study using the patients as their own controls. SETTING: Using a combination of magnetic resonance (MR) phase contrast techniques and an MR compatible bicycle ergometer, blood flow was measured in the superior vena cava, the tunnel from the inferior vena cava, and in the left and right pulmonary arteries during rest and on exercise (0.5 W/kg and 1.0 W/kg). PATIENTS: Eleven patients aged 11.4 (4.6) years (mean (SD)) were studied 6.3 (3.8) years after TCPC operation. MAIN OUTCOME MEASURES: Volume flow measured in all four branches of the TCPC connection during rest and exercise. RESULTS: Systemic venous return (inferior vena cava plus superior vena cava) increased from 2.5 (0.1) l/min/m2 (mean (SEM)) to 4.4 (0.4) l/min/m2 (p < 0.05) during exercise, with even distribution to the two pulmonary arteries. At rest, inferior vena caval flow was higher than superior vena caval flow, at 1.4 (0.1) v 1.1 (0.1) l/min/m2 (p < 0.05). During exercise, inferior vena caval flow doubled (to 3.0 (0.3) l/min/m2) while superior vena caval flow only increased slightly (to 1.4 (0.1) l/min/m2) (p < 0.05). The increased blood flow mainly reflected an increase in heart rate. The inferior vena caval to superior vena caval flow ratio was 1.4 (0.1) at rest and increased to 1.8 (0.1) (p < 0.05) at 0.5 W/kg, and to 2.2 (0.2) at 1.0 W/kg (p < 0.05). CONCLUSIONS: Quantitative flow measurements can be performed immediately after exercise using MR techniques. Supine leg exercise resulted in a more than twofold increase in inferior vena caval flow. This was equally distributed to the two lungs, indicating that pulmonary resistance rather than geometry decides flow distribution in the TCPC circulation.

Blood Flow Velocity↗
PubMed2001

Glaucoma in East Greenlandic Inuit--a population survey in Ittoqqortoormiit (Scoresbysund).

PURPOSE: To determine the prevalence of primary angle-closure glaucoma (PACG) in an isolated Greenlandic Inuit community and to examine the anatomical risk factors for this disease. METHODS: All individuals aged > or =40 years were examined. Visual acuity, refractive error, anterior chamber depth (ACD), intraocular pressure (IOP), gonioscopy, and optic disc characteristics were recorded. RESULTS: Seventy-nine individuals (65% response rate) were examined. Mean IOP was 12.0 mmHg. ACD was shallow and decreased with age and hypermetropia. ACD was deeper than observed in the same community in 1981 and another East Greenland population in 1970. Two subjects had definite PACG (2.5 %). CONCLUSION: This is the first study to use applanation tonometry in a Greenland population and confirms a low IOP as found in other populations of Inuit and Mongolians. ACD measured in 1998 was deeper than in 1981 in the same community which may represent a cohort effect indicating a secular change.

Adult↗
PubMed2001

Transoesophageal echocardiographic monitoring during paediatric cardiac surgery: obtainable information and feasibility in 532 children.

BACKGROUND: We hypothesized that transoesophageal echocardiography (TOE) performed by the anaesthesiologists would be beneficial for monitoring purposes during paediatric cardiac surgery. We present the results for the first 5 years in 532 consecutive children. METHODS: The probe was successfully inserted in 99% of cases and remained in the oesophagus for 211 min on average (range 10-555 min). RESULTS: Insignificant valve leak, single- or biventricular failure and volume depletion were the most common new findings due to TOE. Changes in inotropic strategy and volume replacement were the most frequent interventions. In 45% of the cases, new information was disclosed and, in a total of 8% of cases, decisive information was provided. Except for tracheal extubation in one child who was uneventfully reintubated, no severe complications were identified. CONCLUSIONS: These data stress the safety and ease of performing TOE in children undergoing cardiac surgery. There is evidence for benefit from TOE findings to potentially enhance the therapeutic basis.

Adolescent↗
PubMed2000

Improvement in growth, and levels of insulin-like growth factor-I in the serum, after cavopulmonary connections.

INTRODUCTION: The total cavopulmonary connection, and the bidirectional Glenn anastomosis, are widely used for palliation of patients with complex functionally univentricular hearts. Little attention has been paid to the potential for postoperative growth in children after these operations, which are now performed at increasingly younger age. MATERIAL AND RESULTS: Physical growth, and levels of insulin-like growth factor I in the serum, were measured in 20 patients, aged 11.5 +/- 5.6 years, 2 (0.5-6) years after a total cavopulmonary connection in 12, or a Glenn anastomosis in 8. All patients were in functional class I or II of the categorisation of the New York Heart Association, with excellent haemodynamic and angiographic findings. None of the patients had clinical signs of protein losing enteropathy. Controls included 33 healthy children, aged 11.5 +/- 2.7 years. Preoperatively, the mean Z-scores for weight and height were negative, -1.1 +/- 0.8 and -0.5 +/- 1.5. At follow-up, both parameters had improved significantly by 1.1 +/- 0.9 and 0.8 +/- 1.2 percentiles, and Z-scores were comparable between the two groups (p=0.81 for weight and p=0.88 for height). No correlations were found between haemodynamics and the improvement in growth noted during follow-up. Increases equal to, or greater than 2 standard deviations for weight and height were seen only in children undergoing surgery before the age of 5 years. A significant correlation between age at operation and improvement in growth, however, could not be found. Levels of growth factor measured in the serum were not statistically different from levels in healthy children for either group of patients (p=0.07 for girls and p=0.37 for boys). CONCLUSION: Physical growth improved significantly following the surgical procedures. The concentrations of the growth factor measured in the serum were not different from levels in healthy children, suggesting normal nutritional status in both palliative situations.

Adolescent↗
PubMed2000

Neurohormonal activation late after cavopulmonary connection.

OBJECTIVE: To determine whether patients with cavopulmonary connection have higher levels of vasoactive/water-salt regulating hormones and if so, whether hormone levels are related to postoperative haemodynamics and postoperative follow up. DESIGN: Cross sectional study. SETTING: University hospital. PATIENTS: 20 patients (New York Heart Association functional class I-II), mean age 11 years (range 4 to 22), were studied at a mean of 2 years (0.5 to 6) after a total cavopulmonary connection (TCPC, n = 12) or a bidirectional Glenn anastomosis (BDG, n = 8). INTERVENTIONS: Cardiac catheterisation was performed and blood samples were drawn. Control blood samples were drawn from 33 healthy children, mean age 12 years (6 to 16). MAIN OUTCOME MEASURES: Plasma levels of angiotensin II, renin, aldosterone, arginine, vasopressin, atrial natriuretic factor (ANF), brain natriuretic peptide (BNP). RESULTS: All neurohormones were significantly increased in both TCPC and BDG patients (p < 0. 05), with a fourfold increase in angiotensin II, renin, and aldosterone, and a twofold increase in vasopressin, ANF, and BNP (compared with healthy controls). There was no correlation between haemodynamic variables and hormone levels. Angiotensin II and renin were inversely correlated with time to follow up. All subjects over 15 years (n = 5) had normal neurohormonal levels. CONCLUSIONS: Neurohormones were raised for years after successful cavopulmonary operations but lower levels were observed with time on follow up. This supports the hypothesis that neurohormonal activation is primarily related to altered postoperative physiology and that adaptation takes place over time.

Adolescent↗
PubMed1999

[Transcatheter occlusion of patent ductus arteriosus].

Percutaneous closure of a patent arterial duct was performed in 58 patients. A Rashkind double umbrella was inserted in 20 patients. A supplementary double umbrella or coils were implanted in four who had residual leaks after 12 months. Three complications: embolization, haemolysis and late bacteriaemia were managed successfully without surgery. A detachable PDA coil was inserted in 38 patients. Three coils embolized and one could not be retrieved. At complete follow-up of 28 patients the duct was closed in all. Median procedure duration and fluoroscopy time was 60 min. and 12 min. respectively for double umbrella implantation, and 20 min. and 5 min. for coil insertion. Transcatheter occlusion of the patent duct is effective and carries little morbidity.

Cardiac Catheterization↗
PubMed1999

Reduced vasodilator capacity in syndrome X related to structure and function of resistance arteries.

The combination of angina pectoris, angiographically normal epicardial coronary arteries, and a positive exercise test is referred to as syndrome X. Previous studies have demonstrated an impaired coronary flow reserve and a peripheral vascular dysfunction, suggesting that vascular abnormalities in syndrome X may not be confined to the heart. The aim of this study was to investigate whether any vascular disorder of syndrome X is due to intrinsic structural or functional disturbances in resistance arteries. We compared 16 patients with syndrome X (56.6+/-1.2 years, 3 men) with 15 matched control subjects. Myocardial blood flow was measured with 13N-ammonia positron emission tomography. Forearm blood flow was measured in the brachial artery with high-resolution ultrasound. Gluteal subcutaneous resistance arteries were dissected and mounted on a myograph for measurement of active tension development, lumen diameter, and media thickness. Baseline myocardial blood flow was similar in patients and controls, but dipyridamole-induced hyperemia was decreased in patients (1.67+/-0.13 vs 2.31+/-0.12 ml/ min/g, p <0.01). Patients and controls had similar baseline forearm blood flow, but hyperemic flow after transient occlusion of the brachial artery was impaired in patients (198+/-20 vs 273+/-32 ml/min, p <0.05). Isolated resistance arteries showed no differences in constriction to noradrenaline, or relaxation to acetylcholine, dipyridamole, or nitroglycerin. Furthermore, the ratio between media thickness and lumen diameter were similar in syndrome X patients and controls. Our data show that when compared with a well-matched control group, syndrome X patients have a decreased coronary and peripheral vasodilator capacity. However, this is not reflected by functional abnormalities or structural changes as evaluated in subcutaneous resistance arteries. We conclude that syndrome X is not a generalized intrinsic abnormality of the resistance circulation.

Arteries↗
PubMed1999

Pulmonary and caval flow dynamics after total cavopulmonary connection.

OBJECTIVE: To assess flow dynamics after total cavopulmonary connection (TCPC). DESIGN: Cross-sectional study. SETTING: Aarhus University Hospital. PATIENTS: Seven patients (mean age 9 (4-18) years) who had previously undergone a lateral tunnel TCPC mean 2 (0. 3-5) years earlier. INTERVENTIONS: Pressure recordings (cardiac catheterisation), flow volume, and temporal changes of flow in the lateral tunnel, superior vena cava, and right and left pulmonary arteries (magnetic resonance velocity mapping). RESULTS: Superior vena cava flow was similar to lateral tunnel flow (1.7 (0.6-1.9) v 1. 3 (0.9-2.4) l/min*m2) (NS), and right pulmonary artery flow was higher than left pulmonary artery flow (1.7 (0.6-4.3) v 1.1 (0.8-2. 5) l/min*m2, p < 0.05). The flow pulsatility index was highest in the lateral tunnel (2.0 (1.1-8.5)), lowest in the superior vena cava (0.8 (0.5-2.4)), and intermediate in the left and right pulmonary arteries (1.6 (0.9-2.0) and 1.2 (0.4-1.9), respectively). Flow and pressure waveforms were biphasic with maxima in atrial systole and late ventricular systole. CONCLUSIONS: Following a standard lateral tunnel TCPC, flow returning via the superior vena cava is not lower than flow returning via the inferior vena cava as otherwise seen in healthy subjects; flow distribution to the pulmonary arteries is optimal; and some pulsatility is preserved primarily in the lateral tunnel and the corresponding pulmonary artery. This study provides in vivo data for future in vitro and computer model studies.

Adolescent↗
PubMed1999

Normal pregnancy is associated with enhanced endothelium-dependent flow-mediated vasodilation.

Normal pregnancy is characterized by reduced systemic vascular resistance, which may be mediated by nitric oxide (NO). We compared endothelial vasomotor function in 71 normal pregnant women (13 in first, 29 in middle, and 29 in last trimester) to 37 healthy age-matched controls. With external ultrasound, brachial artery diameter was measured at rest, during reactive hyperemia [with increased flow causing endothelium-dependent dilation (FMD)], and after sublingual nitroglycerin (causing endothelium-independent dilation). Compared with controls, resting flow and brachial artery diameter were significantly higher during the middle and last trimesters. Reactive hyperemia was reduced in all pregnant groups. FMD increased from the first trimester (by 26%), reaching the highest value in the last trimester (to 47% above nonpregnant values). FMD was significantly correlated to pregnancy status (nonpregnant or pregnant) and to vessel size. Nitroglycerin-induced dilation was similar in pregnant and nonpregnant women. A longitudinal study of eight women evaluated in the first, middle, and last trimesters confirmed an increase in FMD throughout pregnancy. The study supports the idea that basal and stimulated NO activity is enhanced in normal pregnancy and may contribute to the decrease in peripheral resistance.

Adult↗
PubMed1998

[Balloon dilatation of congenital aortic stenosis].

We evaluated the catheterization results and follow-up echocardiographic data in all (n = 31) patients undergoing balloon dilatation for congenital aortic valve stenosis at Skejby University Hospital from May 1987 to October 1996. Patients were between three weeks and 35 years of age (median 12.1 years). Peak-to-peak systolic pressure gradient was reduced by 59%, from 74 +/- 17 to 30 +/- 20 mmHg (p < 0.0001). Balloon valvuloplasty was successful in 26 (84%) patients. At follow-up 38 +/- 33 months after balloon valvuloplasty, 19 of these 26 patients (73%) had a persistent reduction in gradient compared with that before valvuloplasty. In the seven patients who had been operated during the follow-up period, balloon valvuloplasty had delayed surgical intervention by 6-97 (median 38) months. Balloon valvuloplasty is an effective, low risk palliative procedure in patients with congenital aortic valve stenosis.

Adolescent↗
PubMed1998

[Non-invasive assessment of endothelial function].

Endothelial dysfunction is an early event in atherosclerosis preceding the formation of plaques. An important functional consequence of endothelial damage is reduced vasodilatory responses to a variety of pharmacological and physiological stimuli including reactive hyperaemia. Hitherto, endothelial function could only be assessed by invasive techniques, but a novel ultrasound based technique has recently been developed, which allows non-invasive evaluation of endothelial function in large systemic arteries such as the brachial artery. The technique is accurate, reproducible and able to differentiate between subjects with and without vascular dysfunction. Impaired endothelial function has been documented in young and adult individuals with various vascular risk factors including cigarette smoking, diabetes mellitus, hypercholesterolaemia, and homocystinuria. A good correlation has been found between both the presence of atherosclerotic lesions and endothelial function in the coronary arteries and the brachial artery. The method may help in identification of individuals with early vascular changes and thereby make risk factor modification possible at a very early stage of the atherosclerotic process. It may furthermore serve as a tool to monitor the impact of prevention and intervention on arterial damage.

Adult↗
PubMed1998

Increased left ventricular systolic function in insulin dependent diabetic patients with normal albumin excretion.

Alterations in cardiovascular function may be an aetiological factor for the development of microalbuminuria in patients with insulin-dependent diabetes mellitus. We studied cardiac function with echocardiography in relation to the degree of albuminuria in 27 insulin-dependent diabetes mellitus patients and 13 healthy subjects. Patients were grouped according to urinary albumin excretion: <20 microg x min(-1) (normoalbuminuric), and 20 to 200 microg x min(-1) (microalbuminuric). None were or had been treated with cardiovascular drugs. The normoalbuminuric patients had a higher heart rate, mean velocity of circumferential shortening, stroke velocity index (a measure of contractility), and aortic peak velocity than controls. No difference in diastolic function was present. In the microalbuminuric group, the stroke velocity index was comparable to values observed in healthy subjects. The increased systolic performance (heart rate and contractility) may contribute to the renal hyperperfusion and glomerular hyperfiltration observed in insulin-dependent diabetes mellitus patients before the development of micro- and in turn macroalbuminuria. The possible cause effect mechanisms should be further studied, as preventive medical treatment of the hypercontractile heart is possible. In conclusion, cardiac contractility is increased in insulin-dependent diabetes mellitus patients with normoalbuminuria and returns to levels observed in healthy subjects when microalbuminuria develops.

Adult↗
PubMed1996

Frequency of systemic microvascular dysfunction in syndrome X and in variant angina.

In addition to coronary vascular abnormalities, patients with syndrome X and variant angina often have systemic vascular symptoms. To determine whether these patients exhibit a generalized abnormality of vasoreactivity, we used high-resolution ultrasound to compare flow responses and endothelial function in the brachial artery in 21 patients with syndrome X, 15 patients with variant angina, and 20 healthy controls. Arterial diameter was measured at rest, after reactive hyperemia (endothelium-dependent flow-mediated vasodilation), and after sublingual glyceryl trinitrate (endothelium-independent vasodilation). The magnitude of hyperemic flow response was measured after transient forearm occlusion. Flow-mediated dilation in the brachial artery did not differ among patients with syndrome X, variant angina, and controls (2.7 +/- 2.3%, 3.8 +/- 3.5%, and 4.2 +/- 3.0%). Endothelium-independent vasodilation in the brachial artery was similar in the 3 groups (16.0 +/- 7.2%, 12.7 +/- 4.6%, and 14.8 +/- 4.9%). Despite a considerable overlap, reactive hyperemia was lower in patients with syndrome X than in patients with variant angina and controls (342+/-86% vs 466+/-184% and 452+/-104%; p < 0.05). These findings indicate that a substantial proportion of patients with syndrome X have a systemic microvascular abnormality, whereas variant angina is predominantly a segmental disorder of conduit vessels.

Angina Pectoris, Variant↗
PubMed1996

Incipient cardiomyopathy in young insulin-dependent diabetic patients: a seven-year prospective Doppler echocardiographic study.

Two echo-Doppler cardiographic investigations were performed 7 years apart in 17 insulin-dependent diabetic children without hypertension or nephropathy in order to detect early signs of cardiac abnormalities in this group without ischaemic heart disease. Relative to two matched control groups, the patients had reduced increase in left ventricular size (p < 0.01) and stroke volume (p < 0.05). An initially reduced end systolic wall stress and increased fractional shortening (p < 0.003) was normalized during the 7 years. Concomitant with early signs of autonomic neuropathy and aortic stiffening, left ventricular filling changed with increased velocity during atrial contraction (p < 0.01) correlating to the decreased stroke volumes (r = -0.57, p = 0.016). These early changes could suggest left ventricular restriction but could also reflect a changed sympathetic/parasympathetic balance in diabetic children. A reduced left ventricular cavity size and increased atrial ejection has thus been described in these insulin-dependent children without hypertension, nephropathy or evidence for ischaemic heart disease, suggesting the existence of a metabolically-induced cardiomyopathy.

Adolescent↗
PubMed1994

[Left ventricular hypertrophy in patients with aortic stenosis. A comparison between electrocardiography and echocardiography].

Using echocardiography (ECHO) as the reference method, the aim of this study was to determine the sensitivity, specificity, and predictive value of the electrocardiogram (ECG) in detection of left ventricular hypertrophy (LVH) in patients with aortic stenosis. Forty-one patients, 18 men and 23 women aged 25-80 years (mean 49 years) with uncomplicated aortic stenosis were studied. ECG-LVH was estimated by standard fixed voltage criteria. ECHO-LVH was defined according to left ventricular mass (LV mass) calculated by the Penn method. In the total material, the correlation between ECG-LVH and ECHO-mass was poor (r = 0.56, p < 0.05). The sensitivity and specificity of the ECG was respectively 50% and 100%. The positive predictive value of the ECG in detection of LVH was high (100%). We conclude that the sensitivity of the ECG in detection of LV hypertrophy is unsatisfactorily low. Accordingly, it is recommended that echocardiography be performed in all patients suspected of aortic stenosis.

Adult↗
PubMed1994

Early recognition of autonomic dysfunction in microalbuminuria: significance for cardiovascular mortality in diabetes mellitus?

The appearance of microalbuminuria in diabetic patients predicts development of macroalbuminuria and coronary heart disease. Autonomic dysfunction in ischaemic heart disease is related to an increased incidence of arrhythmic deaths. To assess sympathovagal balance in relation to microalbuminuria we performed 24-h spectral analysis of RR interval oscillations in 37 insulin-dependent diabetic patients. Patients were divided according to urinary albumin excretion as normo-(< 20 micrograms/min) (n = 12), micro-(> 20 and < 200 micrograms/min) (n = 14) and macro-albuminuria (> 200 micrograms/min) (n = 11). None had symptoms or signs of ischaemic heart disease at clinical examination or during stress testing. Fourteen matched healthy subjects served as controls. Overall RR interval variability was calculated as the 24-h standard deviation. The square root of power of the low-frequency (0.04-0.15 Hz) and high-frequency (0.15-0.40 Hz) component were considered indices of the sympathovagal interaction and vagal function, respectively. Patients with micro and macroalbuminuria had, compared to control subjects, significantly reduced 24-h standard deviation, a much smaller day/night difference in mean RR level and a significantly reduced amplitude of the low frequency and high frequency oscillations, which were even more reduced in macroalbuminuria. The differences in vagal function were also present after correction for mean RR level, and differences in physical training level and smoking. Insulin-dependent diabetic patients who develop microalbuminuria have significantly impaired vagal function and abnormal sympathovagal interaction, which is further deranged in macroalbuminuria. This early autonomic dysfunction may later contribute to a increased risk for sudden cardiac death.

Adult↗