Biomedical subjects

T Fröysaker

Publications and source records attributed to T Fröysaker.

12 recordsLinked to original sources

PubMed1981

Determination of pressure gradient in the Hancock mitral valve from noninvasive ultrasound Doppler data.

The accuracy with which the pressure gradient in the Hancock mitral valve can be determined from noninvasive ultrasound Doppler data was explored in a study of eight adult patients. The mean manometric pressure gradient (delta PM) was determined by performing simultaneous left atrial and left ventricular catheterization. The mean diastolic pressure gradient was also determined from noninvasive ultrasound data (delta PU). Identical cardiac cycles were used to compare delta PM and delta PU. In the eight patients delta PM ranged from 3.0 to 9.0 mmHg and cardiac output from 3.7 to 5.5 l/min. The difference delta PM-delta PU was 0.3 +/- 0.9 mmHg (mean +/- SD). The results thus indicated that noninvasive ultrasound can determine the mean diastolic gradient in the Hancock mitral valve with an accuracy which approaches that attained with conventional manometric methods.

Blood Pressure↗

PubMed1979

Clinical and hemodynamic results after combined aortic and mitral valve replacement with the Lillehei-Kaster pivoting disc valve.

Combined mitral and aortic valve replacement with the Lillehei-Kaster pivoting disc valve prosthesis was performed in 23 patients. Hospital mortality rate was 8.3 per cent. Detailed postoperative clinical and hemodynamic studies were performed after a mean follow-up period of 24.4 months. Replacement of both valves had resulted in a marked symptomatic and hemodynamic improvement with a normal or nearly normal resting value of cardiac output, pulmonary arterial pressure, and pulmonary vascular resistance while left ventricular end-diastolic pressure (LVEDP) had increased significantly. The rise in left ventricular end-diastolic pressure most probably might be related to the simultaneous rise in cardiac output (Starling mechanism), reflecting the severity and irreversibility of the underlying myocardial disease. Most patients also had systolic gradient across the aortic prosthesis, as well as diastolic gradient across the mitral prosthesis. The gradients across the mitral prosthesis were approximately the same as seen after single valve replacement, while the pressure gradients across the aortic prosthesis were somewhat smaller than previously reported. Angiographic studies of the aortic valve movement indicated that the opening angle of the disc was approximately 60 degrees, and thus less than according to the valve specifications.

Adult↗

PubMed1979

Determination of pre- and postoperative flow obstruction in patients undergoing closed mitral commissurotomy from non-invasive ultrasound Doppler data and cardiac output.

A non-invasive ultrasound Doppler system and indwelling thermodilution catheter system were used to determine the pre- and postoperative mitral flow obstruction in eight adults undergoing closed mitral commissurotomy. The effective valve area (Ae) was used as a measure of the obstruction. In the eight patients Ae was 1.08 +/- 0.34(SD) cm. 2 preoperatively and increased to 1.71 +/- 0.43(SD) cm. 2 postoperatively. The technique used in the investigation appears useful for the evaluation of surgical procedures designed to reduce the mitral flow obstruction.

Adult↗

PubMed1979

Mitral insufficiency following myocardial infarction.

Severe mitral insufficiency following myocardial infarction in 15 patients is reported. The mean interval from infarction to surgery was 2.8 years. All patients were operated on with mitral valve replacement and in 14 aortocoronary bypass and/or resection of left ventricular aneurysm was necessary as well. Rupture of one or more heads of the papillary muscle was found in 5 patients. In another 5 the papillary muscles were discoloured, fibrosed and shortened, and in the last 5 patients the mitral incompetence was caused by a marked dilatation of the atrioventricular ring. Five patients (33%) died, 3 early and 2 late after surgery. All the patients who died had a markedly imparied left ventricular function pre-operatively with end-diastolic pressures from 15 to 26 mmHg.

Coronary Artery Bypass↗

PubMed1976

Immediate and long-term results of emergency aortic valve replacement in acute bacterial endocarditis.

A surgically treated material comprising 18 patinets with heart failure from aortic insufficiency during acute endocarditis has been reviewed. At the time of operation the mean duration of heart failure was 3 weeks and duration of endocarditis 9 weeks. Blood culture was positive in half of the patients, 39% had predisposing valve disease, 14 (78%) had a preoperative heart catheterization. The peroperatively measured regurgitation averaged 55%. All 18 patients had an artifical valve implanted, and the mean observation time for 13 long-term survivors was 3 1/3 years. There were 3 postoperative and 2 late deaths. A long-term survival rate of 73% strongly supports early surgical treatment in patients with aortic insufficiency and heart failure during acute endocarditis.

Acute Disease↗

PubMed1975

"In situ" evaluation of the aortic pivoting disc valve prosthesis.

An index of the "in situ" forward flow characteristics of an aortic valve prosthesis is suggested. The effective area index, Ia, is defined as the ratio between the effective orifice area, Aeff, and the area occupied by the valve in the aortic root. Aeff is calculated from a hydraulic formula using peroperative measurements of instantaneous ascending aortic flow, Fao, and the pressure gradient, deltaP. Ia was found to be 0.29 +/- 0.33 (S.D.) for Lillehei-Kaster valves and 0.32 +/- 0.059 (S.D.) for Björk-Shiley valves. The variations in valve performance among the Björk-Shiley valves may partly be due to differences in valve orientation in the aortic root. Attention should therefore be given to the choice of the opening direction of the disc in order to optimize valve performance in the patient.

Aortic Valve Insufficiency↗

PubMed1974