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Biomedical subjects

O W Levang

Publications and source records attributed to O W Levang.

36 records · Page 2Linked to original sources
PubMed1990

[Cardiogenic cause of cerebral embolism].

Cerebral insults of cardiac origin are often of great functional importance. The most common cause is atrial fibrillation. Other sources of cerebral embolies, even if rare, such as cardiac tumors, must not be ignored. Many of these patients present neurologic symptoms. The diagnosis is established on ecco-cardiography. Surgical management is the treatment of choice. We discuss a young patient with multiple cerebral insults and a papillary cardiac tumor.

Adult↗
PubMed1989

[Surgical treatment of angina pectoris in elderly patients].

Twenty-eight patients, age 65 years or more, received aortocoronary bypass surgery during the period 1983-85. There was one early death. There were no serious complications connected with the operation, but increased risk of complications is to be expected with higher age. The postoperative stay in hospital is somewhat longer in the elderly. At follow-up, after 19-52 months, 14 patients were free of symptoms, seven were much improved and four were improved.

Age Factors↗
PubMed1989

The influence of thoracic epidural analgesia on transcapillary fluid balance in subcutaneous tissue. A study in patients undergoing aortocoronary bypass surgery.

Clinical observation and calculation of fluid balance have shown that patients undergoing aortocoronary bypass surgery with thoracic epidural analgesia (TEA) in addition to general anesthesia retain less fluid than patients having general anesthesia only. The present study was designed to investigate whether this effect could be explained by thoracic epidural analgesia influencing the transcapillary fluid balance, i.e. the transcapillary forces (COPpl, COPif, Pif). Interstitial fluid colloid osmotic pressure (COPif) and interstitial fluid pressure (Pif) were measured subcutaneously at heart level by the blister suction technique and the wick-in-needle technique, respectively. Simultaneously plasma colloid osmotic pressure (COPpl) was recorded. Sixteen male patients were allocated to two groups, one having general anesthesia only (controls, n = 8). The other group (TEA, n = 8) received, at the induction of anesthesia, bupivacaine 50 mg via an epidural catheter as an adjunct to general anesthesia. TEA was maintained by continuous infusion for 24 h postoperatively. Preoperatively no intergroup differences were observed in "the Starling forces" (COPpl, COPif, Pif). At the start of extracorporeal circulation COPpl was significantly lower in the TEA-group than in controls. During extracorporeal circulation the transcapillary COP-gradient (COPpl-COPif) was reversed in both groups. At the end of extracorporeal circulation Pif increased to a minor degree in the TEA-group and remained significantly lower than in controls from 3 to 24 h postoperatively. The subcutaneous interstitial tissue could be less expanded postoperatively in the TEA-group, also reflected by a lower increase in Pif.

Aged↗
PubMed1988

Time-related changes in the Starling forces following extracorporeal circulation.

The intra- and postoperative variations of the transcapillary forces [colloid osmotic pressure of plasma (COPpl), colloid osmotic pressure of interstitial fluid (COPif), average hydrostatic pressure in the interstitium (Pif)] were studied in the subcutaneous tissue as a function of time in 13 patients operated on for coronary artery disease using extra-corporeal circulation (ECC). The measurements were performed before operation, during ECC, and during the first 24 hours postoperatively. COPif was measured subcutaneously on the chest both by the wick method and by a noninvasive blister suction method. The latter technique allowed several consecutive measurements in the same individual during the postoperative period. Pif was measured by "wick-in-needle" technique in the same area as the COPif measurements. COPpl was measured in a blood sample collected from a cubital vein. COPpl was reduced about 50% during ECC returned to pre-ECC level within the first 6 hours postoperatively. During ECC COPif was higher than COPpl, reaching its minimum level 4 to 5 hours postoperatively. Measurements performed following ECC showed return of the transcapillary COP-gradient to the normal direction (COPpl greater than COPif). Pre-ECC level of COPif was not entirely obtained during the first postoperative day. Pif increased gradually during ECC and continued to increase the first 2 to 3 hours following ECC. Pre-ECC level was reached within 24 hours postoperatively. The present investigation has demonstrated major dynamic variations in the transcapillary forces in patients undergoing open heart surgery with ECC. There was an increased net capillary filtration (F) intraoperatively predisposing to interstitial edema formation in subcutaneous tissue until several hours following the termination of ECC.

Adult↗
PubMed1988

Transcapillary fluid balance in subcutaneous tissue of patients undergoing aortocoronary bypass with extracorporeal circulation.

Colloid osmotic pressure in plasma (COPpl) from a cubital vein and in interstitial fluid (COPif) in the subcutaneous tissue at heart level, and interstitial fluid pressure (Pif) at the same level, were measured in 18 healthy subjects and in 28 patients requiring aortocoronary bypass. Interstitial fluid was collected via subcutaneously implanted double nylon wicks and Pif was measured with the 'wick-in-needle' technique. Measurements were made preoperatively and 1 1/2 to 8 hours (mean 4 hours) after termination of extracorporeal circulation. Pif rose to 2.3 mmHg above the pre-bypass level. COPpl concomitantly fell from 22.2 to 14.4 and COPif from 12.4 to 10.1 mmHg. These changes were statistically significant. Although the relatively large COPpl drop resulted in a net rise of 3.2 mmHg in filtration pressure, the incidence of pulmonary complications was low and no subcutaneous edema was discernible. The fall in COPif and rise in Pif may be regarded as important edema-preventing mechanisms.

Adult↗
PubMed1987

Surgical treatment of aneurysms of the descending thoracic aorta.

Six patients were operated on for aneurysm of the descending thoracic aorta in 1983-1985 by use of simple cross-clamping and interposition of a Dacron tube graft without extracorporeal circulation. The aneurysm had ruptured in three cases. The patients' mean age was 69 years. Anesthesia and muscle relaxation were obtained by drugs with only minor myocardial depressant action. There was no postoperative mortality or morbidity. Five of the patients have been followed up for at least a year. Careful pharmacologic control of the blood pressure is essential during such surgery. Despite the smallness of the series, it indicates that simple cross-clamping and Dacron graft interposition can be used for treatment of aneurysm of the descending thoracic aorta.

Adult↗
PubMed1981

Aortic valve replacement. A randomized study comparing the Björk-Shiley and Lillehei-Kaster disc valves. Long-term results.

Three hundred patients were selected at random in order to compare the Björk-Shiley (B-S) and Lillehei-Kaster (L-K) valves in the aortic position. The mean follow-up time was 4 3/4 years (range 3 1/4-7 years). There were 15 late deaths in the B-S group and 23 in the L-K group. The incidence of sudden and unexpected deaths was much higher in the L-K than in the B-S group (10:1). The 7-year actuarial survival rate was 82% in the B-S and 76% in the L-K group. In both groups the survival rate was higher in patients with large valves than in those with small valves; in the L-K group this difference was significant (p less than 0.02). The overall thrombo-embolic rate was 3.2 per 100 patient years in the B-S and 2.8 in the L-K group. Valve thrombosis occurred in 3 patients with B-S valves and in 4 with L-K vales. One of the L-K valves was thrombosed early after operation due to faulty suture technique. Of the long-term survivors of working age 80% in the B-S and 70% in the L-K group returned to work. There was a close correlation between functional capacity (NYHA) and the employment rate.

Aortic Valve↗
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

The effect of positive end expiratory pressure after three types of open heart surgery.

It has previously been shown that patients who have undergone mitral valve replacement (MVR) tolerate a positive end expiratory pressure (PEEP) of 1.0 kPa better than patients who have had aortic valve replacement (AVR). the difference was explained by the fact that the mitral patients had pre-existing pulmonary vascular disease. In the present study the effect of PEEP up to 2.0 kPa is investigated in three types of operations: aortocoronary bypass graft (ACBG), mitral valve replacement, and aortic valve replacement; there were five patients in each group. We found that our mitral patients tolerated PEEP better than the two other groups, and that tolerance was not correlated to a higher pulmonary vascular resistance, but rather to a higher level of pulmonary capillary wedge pressure. The influence of PEEP varies in different types of patients and the effect is still difficult to predict.

Adult↗
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

Aortic valve replacement. A randomized study comparing Björk-Shiley and Lillehei-Kaster disc valves. Haematological evaluation.

In this study, 79 randomized patients with either Björk-Shiley (B-S) or Lillehei-Kaster (L-K) aortic disc valves were re-admitted two years after operation for clinical, haemodynamic and haematological evaluation. This paper deals in particular with the haematological results. Cine-aortography was carried out in 76 patients and left ventricular catheterization via the transseptal approach was performed in 43 patients. Haemoglobin concentration, erythrocyte count, platlet count, reticulocyte count, plasma haemoglobin concentration, serum bilirubin, serum iron, serum haptoglobin and serum lactate dehydrogenase were studied in the patients. Postoperatively all patients had normal haemoglobin and erythrocyte count. Haptoglobin was absent or reduced in 43% of patients with B-S valves and in 65% of those with L-K valves. Serum lactate dehydrogenase activity (LDH) was abnormally elevated in 26% of patients in the B-S group and in 65% of those in the L-K group. Mean LDH was significantly higher in the L-K group compared with the B-S group (p less than 0.01). A highly significant linear correlation could be demonstrated between mean systolic pressure difference across the valve (delta pm) and LDH (p less than 0.001). This finding helps to explain why the L-K valves provoke more erythrocyte destruction than the B-S valves, since delta pm proved to be significantly higher in the L-K group. LDH was not significantly increased in 6 patients in whom a paravalvular leakage was demonstrated.

Adult↗
PubMed1978

Aortic valve replacement. A randomized study comparing the Björk-Shiley and Lillehei-Kaster disc valves. Peroperative haemodynamic evaluation and early results.

Three hundred patients were selected at random in order to compare the Björk-Shiley and the Lillehei-Kaster valves in the aortic position. Peroperative haemodynamic evaluations were carried out in 106 cases. The effective orifice area of the valves and the effective area index were calculated. The results indicate that the Björk-Shiley valves utilize the available space in the aortic root about 12% better than the Lillehei-Kaster valves. There were 11 hospital deaths, but none of them were valve related.

Adolescent↗
PubMedDate not supplied

Thrombotic disc impediment in a Medtronic-Hall aortic valve prosthesis diagnosed by Doppler echocardiography followed by successful reoperation.

A case with impeded disc movement caused by thrombus formation in a Medtronic-Hall aortic valve prosthesis is reported. A correct diagnosis, including both mechanism and severity of the prosthesis failure, was established by Doppler echocardiography. The patient was promptly referred for surgery without invasive or other supplementary investigations.

Aortic Valve↗
PubMedDate not supplied

Comparison of intraoperative flow measurements and haemodynamic findings at follow-up in patients with different aortic disc valve prostheses.

Intraoperative as well as postoperative assessment of effective orifice area, determined by relating flow through a prosthetic heart valve to the pressure gradient measured across the valve, provides a data base for comparison of different types of cardiac prostheses. As a measure of valve performance, we have used the derivation of both the effective area according to the Aaslid formula measured intraoperatively and to the Gorlin formula measured at a re-catheterization study. We also established the parameter 'effective index area', Ia or Ii. Ia is defined as the ratio between the effective orifice area and the annulus orifice area, and Ii as the ratio between the effective orifice area and the internal orifice area of the valve housing. The patients included in the study had either Lillehei-Kaster, Björk-Shiley or Hall-Kaster aortic valve prostheses inserted. In most of the Lillehei-Kaster prostheses, Ia varied around 0.27 and Ii around 0.56, while the corresponding values in the Björk-Shiley prostheses were 0.35 and 0.56, increasing to around 0.50 and 0.75 respectively in the Hall-Kaster prostheses.

Adult↗