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Biomedical subjects

B Wranne

Publications and source records attributed to B Wranne.

At least 91 records · Page 5Linked to original sources
PubMed1986

Noninvasive assessment of valve area in patients with aortic stenosis.

A noninvasive method for quantification of aortic orifice area in patients with aortic stenosis is presented and compared with cardiac catheterization data in 24 patients (mean age 67 years). A continuous wave 2 MHz Doppler ultrasound instrument was used to measure the maximal velocity of the aortic jet, and time-averaged pressure drop was obtained by planimetry from the maximal velocity spectral recording using a simplified Bernoulli equation. Left ventricular ejection time was also measured from the spectral recording. Stroke volume was determined with a carbon dioxide-rebreathing method. Noninvasively determined aortic valve areas showed a close correlation with those determined at cardiac catheterization, but mean pressure gradients measured noninvasively were slightly but significantly higher than those measured at catheterization, leading to an underestimation of valve areas with the noninvasive technique, especially when valve areas were large. Neglect of blood flow velocity in the left ventricular outflow tract and recovery of static pressure downstream from the aortic orifice contribute to the difference in the pressure measurements. All patients with a valve area less than 1 cm2 at catheterization, however, also had an area less than 1 cm2 at the noninvasive investigation. This noninvasive approach to the evaluation of the severity of aortic stenosis seems promising for routine clinical use.

Adult↗
PubMed1986

Severe aortic stenosis in elderly patients.

Clinical and non-invasive findings were compared with catheterisation data in 91 elderly patients (mean 65 years, range 52-78) with suspected severe aortic stenosis requiring operation. Heart catheterisation showed that forty nine patients had a valve area of less than or equal to 0.6 cm2, 36 had a valve area of 0.7 - 1.0 cm2, and six an area of greater than or equal to 1.1 cm2. Coexistent aortic regurgitation was found in 85% of the cases, but severe regurgitation was found in only one patient (1%). Seventy seven per cent of patients had chest pain, 74% had dyspnoea, and 46% had exertional vertigo or syncope. Coronary angiography, which was performed in 77 patients, showed coronary artery disease in 24% of those with a history of angina pectoris and in none of those without. All patients had echodense valves; aortic valve calcification was shown by x ray in 76% and in all but one by cineradiography. The peak of the systolic murmur was delayed in 98% of the patients. Although a prolonged left ventricular ejection time was characteristic of severe aortic stenosis, a normal value did not exclude this diagnosis. Most patients (84%) had increased QRS amplitude on the electrocardiogram. Echocardiography showed an increased left ventricular wall thickness in 90% of the patients in whom it was possible to define the myocardial borders. There was an inadequate blood pressure increase in response to exercise in 82%. In about 25% of the patients the exercise test was at variance with the New York Heart Association classification. Findings suggesting severe aortic stenosis resembled those reported for younger age groups. When most findings point to severe aortic stenosis, the absence of a single symptom or non-invasive sign does not exclude severe aortic stenosis.

Aged↗
PubMed1986

Ultrasound assessment of ductal closure, pulmonary blood flow velocity, and systolic pulmonary arterial pressure in healthy neonates.

Ultrasound Doppler was used to establish time of ductal closure, normal values for blood flow velocity in the pulmonary artery (PA), and time interval between pulmonary valve closure (Pc) and tricuspid valve opening (To) in 37 healthy neonates. Ductal closure had occurred in 23% of the children within 12 h after delivery and in 53% during the next 12 h. No open ductus was found after 30 h of age. Maximal blood flow velocity was 0.90 +/- 0.09 (SD) m/s during the first five days of life and 1.12 +/- 0.17 m/s at the age of 14-30 days. The Pc-To interval is known to reflect systolic PA pressure in adults. The Pc-To interval decreased significantly (p less than 0.01) from an average of 0.059 +/- 0.016 s at 3.5-12 h of age to 0.048 +/- 0.011 at 19-36 h of age and thereafter successively to 0.027 +/- 0.004 s at 20-30 days of age. This value is only slightly higher than that of 0.015-0.020 s for normal adults at comparable heart rates. These data suggest a rather sharp decline of systolic PA pressure during the first day of life and thereafter a slower decline; normal adult values are approached but not reached at 3-4 weeks of age. The Pc-To value seems to be of limited value in the early neonatal period, because even normal neonates have increased values with a large individual variation. After 3-4 weeks of age, an increased value should be taken as an indication of increased systolic PA pressure.

Blood Flow Velocity↗
PubMed1985

Non-invasive assessment of aortic and mitral regurgitation.

A non-invasive method for the assessment of the degree of regurgitation in aortic and mitral regurgitation is presented. Regurgitant volume was obtained by subtracting effective stroke volume (SV eff), determined with a CO2-rebreathing method, from total stroke volume (SV tot) determined by M-mode echocardiography. Regurgitant volume and a non-invasive regurgitant index (SV tot/SV eff) were compared with semiquantitative angiography in 49 patients [mean age = 62 +/- 11 (SD) years], who on the basis of the angiography were allocated to four different groups (no, slight, moderate and severe regurgitation). Eighteen normal subjects [mean age = 26 +/- 9 (SD) years], not subjected to angiography, served as a control group and are included in the group without regurgitation. When the cube formula was used for the determination of SV tot, the average regurgitant volumes for the different groups were: 0.5 +/- 24 (SD), 15 +/- 22, 85 +/- 48 and 138 +/- 65 ml and the corresponding SV tot/SV eff ratios were: 1.0 +/- 0.3, 1.2 +/- 0.3, 2.4 +/- 0.8 and 3.8 +/- 1.5, respectively. There were significant differences (P less than 0.01) between the groups with slight, moderate and severe regurgitation respectively both for regurgitant volume and regurgitant index, but no significant difference between the group with slight regurgitation and the group without regurgitation. This study suggests that the severity of aortic and mitral regurgitation can be estimated non-invasively by the combined use of a CO2-rebreathing method and echocardiography.

Adult↗
PubMed1985

Quantification of heart valve regurgitation: a critical analysis from a theoretical and experimental point of view.

A theoretical analysis is presented regarding factors of importance for the determination of distance of intrusion of the regurgitant jet in heart valve regurgitation. The analysis is based on hydrodynamic theory. In the idealized model situation, for a circular hole, the intrusion of the regurgitant jet is linearly related to the product of the fluid mean velocity in the orifice and the diameter of the orifice. This was also shown to be true in an experimental fluid model. Thus, volume regurgitation cannot be quantified by the measurement of distance of intrusion of the regurgitant jet alone. On the other hand, an estimate of volume regurgitation can, in the idealized situation, be obtained if mean fluid velocity in the orifice, distance of intrusion of the jet and regurgitation time are known.

Aortic Valve Insufficiency↗
PubMed1984

Prenalterol as long-term therapy for chronic congestive heart failure. A randomized cross-over trial.

Ten patients with severe chronic congestive heart failure (CHF) due to ischaemic heart disease treated with digitalis and diuretics were randomly allocated to oral treatment with prenalterol (100-200 mg daily in addition to their basal treatment) or to intensified treatment with diuretics in a cross-over trial. A wash-out period of 1-4 weeks was allowed between the two modes of treatment. Most of the patients demonstrated subjective improvement during prenalterol therapy, but this improvement could not be verified objectively by exercise test, echocardiography, chest X-ray or weight measurements. No serious side-effects of either mode of treatment were observed. Heart rate was significantly lower during exercise when the patients were treated with prenalterol than during the control periods or during intensified conventional treatment, indicating that prenalterol acts as a beta-adrenergic receptor blocker during exercise in this patient group. The results indicate that prenalterol is a partial beta-receptor agonist without superior beneficial effects compared to those of intensified conventional treatment in patients with chronic, severe CHF.

Adrenergic beta-Agonists↗
PubMed1983

Non-invasive determination of effective stroke volume. Evaluation of a CO2-rebreathing method in normal subjects and patients.

A CO2-rebreathing method for the determination of stroke volume (SV) was evaluated at rest by comparison with the direct Fick technique in 50 randomly selected patients with valvular heart disease. Patients with intracardiac shunts were excluded. Objective criteria for acceptance of a measurement were set to ensure reliable results. Forty-six of the 50 patients fulfilled these criteria. The rebreathing manoeuvre is, in itself, an effort for the patient, leading to a change in steady state which excludes simultaneous comparison with the direct Fick method. Day-to-day variation of the SV measured with the CO2-method was therefore assessed first, and found to be low. Because of this low day-to-day variation, a comparison of stroke volumes measured one day with the CO2-method and next day with the direct Fick technique was found to be acceptable. In the determination of SV in the supine position, there was no significant difference between the two methods (SVCO2 = 5.2 + 0.90 X SVFick, r = 0.90, SDres = 9.4 ml, n = 46), while cardiac output was significantly higher when measured with the CO2 technique than with the direct Fick method (22%, P less than 0.001). Ten of 12 patients with signs of obstructive lung disease managed to produce registrations which fulfilled the criteria of acceptance. The method is well suited for clinical use.

Adolescent↗
PubMed1983

Effect of increased blood oxygen affinity on skeletal muscle surface oxygen pressure fields.

A chronic left displacement of the blood O2 dissociation curve (ODC) was achieved in rats by administering cyanate over a period of 14 days. Control rats received NaCl. An acute left displacement of the ODC was achieved by exchange transfusion with bisulfite-treated erythrocytes. Control rats for this series received an exchange transfusion with fresh heparinized blood. In both series, skeletal muscle surface O2 pressure fields (expressed as PO2 histograms) were measured with the rats anesthetized, curarized, and artificially ventilated. The animals with chronically left-shifted ODC had normal PO2 histograms (for definition see DISCUSSION) when breathing air; during hypoxia (FIO2 0.12) four of the eight experimental and three of the seven control animals developed abnormal histograms, and all animals had normal histograms on return to air breathing. The majority, but not all, of the animals that were to receive exchange transfusions of left-shifted ODC blood had normal histograms before the transfusion, which caused some to become abnormal and others to become normal. Similar results were obtained in the control animals that received normal blood. The results do not provide evidence for an adverse effect of a left-shifted ODC on muscle tissue oxygenation.

Animals↗
PubMed1983

Tissue oxygenation and muscular substrate turnover in two subjects with high hemoglobin oxygen affinity.

Oxygen transport to and substrate turnover in leg muscle were studied at rest and during light and heavy upright bicycle exercise in two brothers with a hereditary hemoglobinopathy associated with high oxygen affinity (P50 = 13 mmHg). Femoral venous oxygen tension was below normal and femoral venous oxygen saturation above normal at rest and during exercise. Thus, the arterial-femoral venous oxygen saturation difference was decreased. Despite a compensatory increase in hemoglobin concentration, the arterial-femoral venous oxygen content difference tended to be below normal at heavy exercise. Approximately 25% of the oxygen was delivered via the abnormal hemoglobin at relative heavy exercise. Arterial lactate levels, lactate release, and muscle lactate concentration were not increased at any level of exercise. Glucose, alanine, pyruvate, and glycerol turnover were essentially normal, but the glycogen and creatine phosphate stores were abnormally depleted at the termination of heavy exercise. The exercise electrocardiogram (ECG) was normal, indicating that myocardial oxygenation was adequate. Muscle-surface oxygen pressure fields were normal at rest (not investigated during exercise). It is concluded that the high oxygen affinity of the hemoglobin in our two subjects did not lead to heart or skeletal muscle hypoxia during heavy exercise, as judged from the ECG and from the leg lactate turnover. Despite the lack of evidence for muscle hypoxia, the subjects experienced leg muscle fatigue and the creatine phosphate and glycogen stores were depleted more than normally.

Adenosine Triphosphate↗
PubMed1982

Hyperinflation on hyperventilation-a simple test to detect early airway disease.

The hypothesis was raised that an increased end-expiratory lung volume when switching over from normal to hyperventilation (positive delta FRC) can be used as a criterion of early obstructive lung disease. In 20 normal subjects and in 24 patients with suspect or manifest lung disease delta FRC at breathing frequencies of 40, 60 and 80 min-1, forced expiratory volume in one second (FEV1), vital capacity (VC), maximal expiratory flow at 50 and 25% of VC (MEF50 and MEF25) and closing volume (CV) were determined. FEV% (FEV1 X VC-1 X 100) and CV% (CV X VC-1 X 100) were calculated. delta FRC40 correlated negatively with FEV%, MEF50 and MEF25 for normals and patients separately with no difference between the groups. The residual standard deviation of delta FRC40 on FEV% was significantly reduced when MEF50 and MEF25 was included. delta FRC40 did not correlate with CV or CV%. delta FRC60 and delta FRC80 did not correlate with MEF50 and MEF25. The reproducibility of delta FRC40 was of the same order as the other variables studied. A delta FRC40 of +0.31 corresponded to MEF50 and MEF25 values 2 SD below the reference value. This suggests that a positive delta FRC40 of more than 0.31 indicates airway obstruction.

Adolescent↗
PubMed1982

[Effects of oestrogens on cardiovascular risk factors in patients with carcinoma of the prostate (author's transl)].

16 patients with advanced carcinoma of the prostate were studied in a prospective trial during treatment with oestrogens. Changes in plasma levels of gonadotropins (LH and FSH) and testosterone as well as salt-water balance, antithrombin III, fibrinolytic activity, plasma lipoproteins known to influence the risk of cardiovascular complications, were recorded during the initial 2 months. The plasma testosterone, LH and FSH concentrations were suppressed. The plasma volume was increased and the plasma albumin concentration was decreased. The antithrombin III concentration and the tissue fibrinolytic activity were decreased. The low density lipoprotein (LDL) level decreased and the high density lipoprotein (HDL) level increased. The recorded changes of cardiovascular risk factors indicate that the risk of water retention and thereby congestive heart failure and the risk for thromboembolic disease are increased during oestrogen treatment. The changes in lipoproteins with a marked elevation of the HDL/LDL ratio are thought to retard the development of atherosclerosis.

Aged↗
PubMed1981

Diagnostic value of questionnaires regarding angina pectoris and oesophageal dysfunction in patients with chest pain.

Questionnaires aimed at detecting angina pectoris and oesophageal dysfunction (OD) were used in 281 patients with central chest pain of a type which gave suspicion of ischaemic heart disease (IHD). Signs of IHD were found in 208 patients (74%), 172 of whom had a positive angina pectoris questionnaire. The sensitivity of the questionnaire regarding the diagnosis of IHD was 83%, the specificity 48% and the predictive accuracy 82%. OD was found in 137 of the of the 281 patients (49%). "Do you often have heartburn" was the question which distinguished the OD and non-OD groups the best (p less than 0.001). The sensitivity of this question in detecting OD was 34%, the specificity 93% and the predictive accuracy 82%. In conclusion, the diagnostic value of the angina pectoris questionnaire was limited by a low specificity and the diagnostic value of the oesophageal questionnaire by a low sensitivity in these patients with chest pain.

Angina Pectoris↗