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Biomedical subjects

K Levorstad

Publications and source records attributed to K Levorstad.

At least 37 records · Page 2Linked to original sources
PubMed1985

Measurement of mitral regurgitation by Doppler echocardiography.

In an attempt to develop a new approach to the non-invasive measurement of mitral regurgitation, Doppler echocardiography and left ventriculography were performed in 20 patients without valvar heart disease (group A) and in 30 patients with pure mitral regurgitation (group B). Volumetric flows through the aortic and the mitral orifices were determined by Doppler echocardiography. Aortic flow (AF) was calculated as the product of the aortic orifice area and the systolic velocity integral. The mitral flow (MF) was calculated as the product of the corrected mitral orifice area and the diastolic velocity integral. The mitral regurgitant fraction (RF) was calculated as RF = 1 - AF/MF. In group A aortic and mitral flow were very similar and the difference between the two did not differ significantly from zero. In group B the mitral flow was significantly larger than the aortic flow. There was a good correlation (r = 0.82) between the regurgitant fraction determined by Doppler echocardiography and the regurgitant grades determined by left ventriculography. The regurgitant fraction increased significantly with each grade of severity. These results show that Doppler echocardiography can be used to give a reliable measure of both aortic and mitral flow. This technique is a new and promising approach to the non-invasive measurement of mitral regurgitation.

Adult↗
PubMed1984

Heart volumes in healthy middle-aged men. A seven-year prospective investigation.

The heart volume was followed over a 7-year period in 819 healthy men aged 40 to 59 years. The subjects were selected on the basis of unremarkable clinical findings and technically satisfactory films on two occasions 7 years apart. On both occasions the mean heart volume in the upright position was 390 ml/m2 (96.6% below 500), uninfluenced by age, and moderately larger in subjects with high physical fitness. Inclusion of subjects who were healthy during the baseline examination, but who developed heart disease or other diseases during the follow-up period, would have increased the mean heart volume by 15 ml/m2. Latent coronary heart disease did not influence the heart volume, but intercurrent myocardial infection increased the follow-up volumes significantly.

Age Factors↗
PubMed1983

Tolerability of iohexol after injection into healthy volunteers.

The effects of iohexol, a new non-ionic contrast medium, after intravenous injection into humans are reported. After injection of small doses into 2 subjects, iohexol was injected intravenously into 20 healthy male volunteers in doses of 125 to 500 mg I/kg body weight. A large number of physiologic, biochemical, hematologic and pharmacokinetic parameters were analysed. The results indicated that iohexol was well tolerated and that clinical trials in patients could be undertaken.

Adult↗
PubMed1983

Iohexol compared with metrizoate in urography.

Urography was performed in 20 patients using the new non-ionic contrast medium iohexol (Omnipaque) and in 22 patients using the conventional ionic medium metrizoate (Isopaque) in a randomized, double blind comparison. Iohexol caused significantly less subjective reactions and less tachycardia than metrizoate. No significant difference between the contrast media was observed regarding the influence on blood pressure, hematologic parameters, or clinical chemical parameters in blood and urine. Urographic films of similar and high quality were obtained with both contrast media.

Adolescent↗
PubMed1983

Tolerability and usefulness of iohexol in cardioangiography. II. A double blind comparison with metrizoate.

The new non-ionic contrast medium iohexol (Omnipaque) was compared with the ionic medium sodium meglumine calcium metrizoate (Isopaque Coronar) in a double blind, two-group trial. Iohexol resulted in significantly fewer and smaller subjective reactions than metrizoate. Changes of left ventricular and aortic pressure were statistically significantly less after injection of iohexol than of metrizoate. ECG recordings did not significantly differ in the two groups. Analysis of biochemical parameters showed no statistical differences between the two groups. Determination of serum enzyme activities revealed no signs of myocardial injury, and no impairment of glomerular filtration rate was detected by radionuclear renal function test. Similar radiographic quality was obtained with both media.

Adult↗
PubMed1981

Long-term results after left ventricular aneurysmectomy.

Twenty-six patients (21 men and five women) with a mean age of 54.8 years have been reinvestigated nine to 62 months (mean 29.7) after left ventricular aneurysmectomy. Preoperatively left ventricular angiography disclosed an anterior aneurysm in all cases, which was large in 15 (57%) and small to medium in 11 (42%). At follow-up a large residual aneurysm was found in five (19%), a small to medium one in 13 (50%), and akinesia without aneurysm in eight (31%). The sum of ST elevation (sigma ST) in praecordial leads in the electrocardiogram was reduced from a mean value of 11.2 mm to 7.7 mm. In no patient did ST segments return to normal after operation. Preoperatively, mean sigma ST was identical in patients with large and with small to medium aneurysms. At reinvestigation mean sigma ST was identical in patients with large and with small to medium residual aneurysms as well as in patients with akinesia. Left ventricular end-diastolic pressure before angiography was reduced from a mean value of 21.5 mm to 15.1 mmHg and after angiography from 26.7 mm to 21.1 mmHg. Progression of coronary artery stenoses was a characteristic finding in patients whose left ventricular end-diastolic pressures did not return to normal. These patients had a longer follow-up time than those with no progression of coronary disease, who all showed an improvement in left ventricular end-diastolic pressure. Six patients who had coronary bypass grafting performed had unchanged left ventricular end-diastolic pressures at follow-up. The results indicate that progression of coronary artery disease may be responsible for an eventual further deterioration in left ventricular function after aneurysmectomy. Additional bypass grafting did not result in improved left ventricular function.

Adult↗
PubMed1980

Aortic valve replacement. A randomized study comparing the Björk-Shiley and Lillehei-Kaster disc valves. Transvalvular regurgitation and occurrence of paravalvular fistulas.

Three hundred patients were selected at random in order to compare the Björk-Shiley (B-S) and the Lillehei-Kaster (L-K) valves in the aortic position. The transvalvular regurgitation was evaluated by peroperative flow recordings in 97 cases. The leakage was found to be 7.6% and 7.5% of forward flow in the B-S and L-K valves, respectively. The regurgitant flow pattern, however, was different in the two groups, as leakage on closure was significantly larger in the L-K valves, and the leakage after closure of the disc was significantly larger in the B-S valves. Follow-up cine-aortography was carried out two years postoperatively in 91 patients. The contrast leakage through the valves was found to be minimal (Grade I) in about 90% in both groups. In one patient with a L-K valve no leakage could be demonstrated. In the remaining patients the leakage was moderate (Grade II). Paravalvular fistulas were demonstrated in three patients from each group. In one patient the paravalvular regurgitation was marked (Grade III), in the others moderate (Grade II). Cine-aortography was also carried out in a further 9 patients, in whom a paravalvular leakage was suspected according to clinical follow-up examinations. In four of these patients a paravalvular regurgitation was demonstrated. The leakage was moderate in two patients and severe (Grade IV) in another two, who were successfully re-operated on.

Aortic Valve↗
PubMed1979

Primary results with the new Hall-Kaster disc valve prosthesis in mitral position.

The Hall-Kaster central flow prosthetic heart valve was introduced in 1977 in an attempt to improve the hemodynamics of the disc valve prostheses. Towards this accomplishment, innovations in the tilting axis, the disc guidance mechanisms, and disc translational freedom cooperate to improve flow through both orifice segments of the open valve. The present study reports on the primary clinical and hemodynamic findings in the first 20 patients (mean age 57.6 years) with isolated mitral valvular disease, examined 3--4 months after insertion of the Hall-Kaster disc valve prosthesis. The hemodynamic findings displayed low gradients and high calculated valve areas (5). At rest, the mean diastolic pressure gradient across the smallest prosthesis used (O.D. 27) averaged 3.0 mmHg, vs. 2.6 mmHg across the largest valve sizes (O.D. 29--31). Calculated valve area was on an average 3.08 cm2 for the smaller valve, and 3.47 cm2 for the larger valves, which corresponded to an utilization of 81% and 77% of the orifice area measured in vitro. A comparison with earlier studies of mean diastolic mitral gradients with different mitral prostheses indicates that the Hall-Kaster disc valve represents an improvement towards a hemodynamically more efficient prosthesis for mitral valve replacement.

Aged↗
PubMed1979

Late sudden death after surgical correction of coarctation of the aorta. Importance of aneurysm of the ascending aorta.

Follow-up studies averaging 12 years postcorrective surgery of 343 patients with coarctation of the aorta disclosed 38 late deaths, 15 of which were sudden, unexpected and probably cardiovascular. All but two patients were normotensive postoperatively, and in 4 of these the cause of death was proven dissecting aneurysm of ascending aorta. In another patient this aneurysm was repaired surgically and in 3 other patients chest X-ray had shown a dilated ascending aorta before death. At follow-up the ascending aorta was dilated angiographically in 4 survivors, who had moderate systolic hypertension and aortic valve disease. The high incidence of aneurysm of ascending aorta in patients with coarctation is probably due to hypertension during the growth period, possibly in combination with congenital weakness of the aortic wall, and to concomitant aortic valve lesion.

Adolescent↗
PubMed1979

Aortic valve replacement. A randomized study comparing the Björk-Shiley and Lillehei-Kaster disc valves. Late haemodynamics related to clinical results.

In this study, 78 randomized patients with either Björk-Shiley (B-S) or Lillehei-Kaster (L-K) aortic disc valve prostheses were re-admitted for clinical and haemodynamic evaluation. The patients were selected that those with narrow aortic roots were over-represented. Cine-aortography was carried out in 75 patients and left ventricular catheterisation via the transseptal approach was performed in 42. The clinical improvement was striking, although the number of patients still incapacitated was relatively large in patients with the small L-K valves (Nos. 14 & 16). Peak-to-peak and mean systolic pressure differences across the valves were significantly lower in the B-S than in the L-K valves, particularly when the small valve sizes were compared. Left ventricular end-diastolic pressure (LVEDP), which was elevated in most patients before operation, decreased significantly to normal levels in the B-S group. In the L-K group, LVEDP did not decrease significantly and was on the average still above the normal level after operation, probably due to the relatively large pressure gradients. The study indicates that the L-K valves Nos. 14 & 16 in particular represents a resistance to flow that is too large to be acceptable in clinical practice.

Adult↗
PubMed1979

Amipaque in coronary angiography.

Comparative studies between Isopaque Coronar and Amipaque with equal concentration of iodine (370 mg I/ml), have been carried out in more than 130 patients. Hemodynamic and electrocardiographic registrations before, during and after selective coronary angiography showed that the diastolic blood pressure and heart rate decreased significantly less with Amipaque, while no significant differences were observed in various ECG parameters. Interestingly, it was observed that the left coronary artery contrast transit time was longer when using Amipaque. This phenomenon may reflect a difference between ionic and nonionic contrast media, but also a difference in viscosity. The quality of the angiograms was the same irrespectively of the contrast medium used.

Blood Pressure↗
PubMed1977

Amipaque: a new contrast medium in coronary angiography. Report of a double-blind study in man.

Isopaque Coronar and Amipaque (metrizamide) were evaluated in a comparative double-blind study of 30 patients with heart disease undergoing selective coronary angiography. Amipaque alone was also used for 9 additional patients undergoing left ventriculography, aortic root injection, and selective coronary angiography. Amipaque resulted in significantly less of a decrease in diastolic pressure and heart rate, reduced chest pain and heat sensation, and longer coronary contrast transit time. Electrorocardiographic parameters and image quality were equivalent with the 2 agents. No pathological changes were noted in the 9 patients undergoing complete angiocardiographic study.

Adult↗