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Biomedical subjects

O Geiran

Publications and source records attributed to O Geiran.

At least 73 records · Page 4Linked to original sources
PubMed1990

Changes in cardiac dynamics by opening an interventricular shunt in dogs.

Changes in right and left ventricular (RV, LV) dynamics caused by an interventricular shunt were examined in open-chest dogs. At a pulmonary to systemic blood flow ratio of 1.7 +/- 0.2 pulmonary flow increased by 53 +/- 13%, whereas aortic flow decreased by 9 +/- 2%. Shunt flow was continuous from the left to the right ventricle throughout the cardiac cycle, but 72 +/- 4% took place during the LV ejection phase. Peak systolic LV pressure declined by 6 +/- 3 mm Hg, LV end-diastolic segment length (SL) rose, and systolic shortening of the SL increased. Peak systolic RV pressure rose from 28 +/- 3 to 36 +/- 3 mm Hg and RV end-diastolic and end-systolic SL rose almost equally. Accordingly, RV systolic SL shortening did not rise despite the substantial augmentation in RV outflow. The transseptal end-diastolic pressure gradient did not rise, while the transseptal peak systolic gradient decreased when the shunt was opened. Similarly directed alterations were observed when the shunt was opened at different preloads and when the shunt flow was varied. Local work in the anterior wall of the right ventricle (calculated from the RV pressure SL loop) rose by 26 +/- 4%, whereas RV stroke work (product of mean systolic right ventricular pressure and pulmonary flow) rose by 57 +/- 12%; difference, P less than 0.05. LV stroke work and local work in anterior LV free wall rose in proportion when the shunt was opened.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Heart transplantation in patients with severe pulmonary hypertension and increased pulmonary vascular resistance.

Irreversibly increased pulmonary vascular resistance is a contraindication for cardiac transplantation. At our hospital patients referred for recipient evaluation with systolic pulmonary artery pressure greater than 50 mmHg and pulmonary vascular resistance greater than 2 Wood units (Wu) are tested with intravenous sodium nitroprusside for reversibility. In 23 patients whose increased systolic pulmonary artery pressure (67.4 +/- 10.4 mmHg) and resistance (4.8 +/- 2.4 Wu) were reduced by nitroprusside, orthotopic heart transplantation was performed without early mortality. Right heart catheterization after transplantation revealed a significant and persistent fall of the elevated pulmonary artery pressure and pulmonary vascular resistance. We conclude that if severe pulmonary hypertension and elevated pulmonary vascular resistance are reversible with nitroprusside, the patient can safely undergo heart transplantation.

Adult↗
PubMed1989

[Vascular surgery in Norway in 1986].

A questionnaire on vascular surgical activity in 1986 was sent to all Norwegian surgical departments (80). 78 units responded. Vascular surgery is not performed in the two hospitals who did not respond. Altogether 3,509 vascular operations were performed in 1986 (844 operations per million inhabitants). By comparison, 2,529 operations were performed in 1981, 2,039 in 1978 and 1,100 in 1975. The largest increase was recorded in operations for abdominal aortic aneurysm, carotid artery stenosis, arterial emboli and angio-access surgery. Elective vascular operations were performed in 41 departments, whereas an additional 16 did emergency vascular surgery only. 34% of the operations were performed by members of the junior staff. Differences between the five health regions have decreased since the investigation in 1981. The highest activity was observed in Health Region V, where 986 operations were performed per million inhabitants. Vascular surgical activity is increasing in Norway. This must be taken into account when estimating the number of residencies and staff positions for vascular surgery. The increasing need for vascular surgery should also influence priorities in our national health system.

Humans↗
PubMed1989

Experiences with closed chest, temporary atrio-arterial, ventricular bypass with a centrifugal pump after open heart surgery.

Twelve patients with refractory myocardial failure following open heart surgery were treated with a temporary left (10), right (1) or biventricular (1) assist circuits driven by extracorporeal pumps. Ten of 11 patients were weaned from the pump oxygenator. During left ventricular assist, maximal pump flow was 2.2 +/- 0.6 l/min per m2 at a cardiac index of 2.5 +/- 0.9 l/min per m2. Diuresis was above 1 ml/kg body weight per h in 7 of 9 patients perfused for 13-36 h. Seven patients were weaned from the assist pump after 13-33 h of ventricular bypass with 4 hospital survivors. Two patients died after circulatory assistance of multiple organ failure, 1 from cerebral damage. In the other patients, the main problems were cardiac. Three patients are currently long term survivors 12-17 months after surgery.

Cardiopulmonary Bypass↗
PubMed1989

Evaluation for left ventricular aneurysm resection: a prospective study of clinical and haemodynamic characteristics.

A consecutive series of 97 patients with a left ventricular aneurysm (LVA) was evaluated for aneurysmectomy. A wide range in left ventricular (LV) function was found. Angina pectoris was the primary indication (51%) in 55 patients who were operated upon, whereas poor LV function was the main reason (67%) for rejecting surgery in 42 patients. Operative mortality was 9% and exclusively seen in patients with congestive heart failure and/or sustained ventricular arrhythmias. Functional status improved from (NYHA) 3.0 +/- 0.7 to 2.3 +/- 0.5 (P less than 0.0001) after surgery, while haemodynamics at rest remained unchanged. In the medically treated group, 10 patients underwent heart transplantation without mortality during follow-up. Of the remaining 32, 7 had died (22%), all with severely impaired LV function. The best prognosis with no deaths was observed in the 14 medically treated patients with moderate complaints and well preserved LV function. Those with poor LV function and/or ventricular arrhythmias had a poor prognosis whether they were treated medically or by conventional aneurysm surgery. In young selected patients with a short life expectancy, heart transplantation may represent an alternative.

Angina Pectoris↗
PubMed1989

Changes in the coagulation and fibrinolytic systems during and after cardiopulmonary bypass surgery.

Components of the coagulation and fibrinolytic systems were determined in patients undergoing open heart surgery with cardiopulmonary bypass. The variables studied included prothrombin, antithrombin-III, spontaneous plasmin activity, plasminogen and functional antiplasmin activity. The variables were measured using chromogenic peptide substrate assays. A marked, transitory, increase in spontaneous plasmin activity prior to cardiopulmonary bypass, but after heparin injection was found. A decrease in antiplasmin activity during bypass was observed, while actual plasminogen level, when correcting for hemodilution, was unchanged. Both prothrombin and antithrombin-III paralleled the decrease in hemoglobin concentration during bypass. These findings suggest that the injection of heparin induced a transient activation of the fibrinolytic system, whereas no detectable consumption of the measured coagulation variables was observed.

Adult↗
PubMed1989

Different activation patterns in the plasma kallikrein-kinin and complement systems during coronary bypass surgery.

Components of the plasma kallikrein-kinin and complement systems were determined in patients undergoing open heart surgery with cardiopulmonary bypass. Spontaneous kallikrein activity (KK), plasma prekallikrein (PKK), functional kallikrein inhibition capacity (KKI), C3 activation products (C3-act), and the terminal complement complex (TCC) were measured. A marked, transitory increase in KK and a decrease in PKK were found prior to cardiopulmonary bypass just after heparin injection. An additional decline in PKK and KKI during bypass with a return to near control levels in the postoperative period was observed. C3-act increased in all patients during bypass, reaching a peak value at wound closure. The TCC concentration also increased significantly during cardiopulmonary bypass, returned to control levels in the early postoperative period, and then increased again in the late postoperative period. It is concluded that activation of the kallikrein-kinin system started after injection of heparin, prior to cardiopulmonary bypass. Activation of both the initial and the terminal complement cascade, however, started only after onset of cardiopulmonary bypass.

Adult↗
PubMed1989

Encircling endocardial ventriculotomy for malignant ventricular arrhythmias. Effect on cardiac performance.

Cardiac performance and hemodynamics were studied with radionuclide ventriculography in 19 survivors of aneurysmectomy and encircling endocardial ventriculotomy for recurrent, sustained ventricular arrhythmia (group I). To characterize the effect of the ventriculotomy on cardiac function, comparisons were made with a similar group of patients who underwent aneurysm surgery for angina pectoris and/or congestive heart failure (group II). Functional classification revealed no difference between the groups and they achieved the same level of exercise after surgery. No intergroup difference was found postoperatively with respect to right or left ventricular ejection fraction, regional ejection fractions, peak ejection rate, cardiac index or stroke volume. Peak filling rate was also similar, as were cardiac volumes. Exercise did not change any parameter of this intergroup similarity. The authors conclude that most patients with moderately impaired left ventricular function who undergo left ventricular aneurysmectomy with encircling endocardial ventriculotomy do not differ in postoperative hemodynamics and systolic or diastolic function from those treated with simple aneurysmectomy.

Adult↗
PubMed1989

Changes in the plasma protease systems during open-heart surgery with dextran vs. Ringer acetate as priming solution.

Two different priming solutions for cardiopulmonary bypass (CPB) were studied in regard to possible influence on the plasma protease systems. The study was performed on 20 patients undergoing elective coronary artery bypass grafting. In ten cases the priming solution contained 1,000 ml dextran (MW 70,000) and in ten it consisted only of Ringer's acetate solution. The same level of haemodilution was established during CPB in the two groups. Clinical variables and laboratory data were monitored. Spontaneous kallikrein activity, plasma prekallikrein, functional kallikrein inhibition capacity, spontaneous plasmin activity, plasminogen, functional antiplasmin activity, prothrombin and antithrombin-III were measured, using chromogenic peptide substrate assays before and during CPB as well as in the postoperative period. The antiplasmin activity decreased more in the dextran than in the Ringer group following cardiopulmonary bypass but the difference was without clinical significance. No statistically significant intergroup difference was found in the other measured variables of the kallikrein-kinin, fibrinolytic and coagulation systems.

Aged↗
PubMed1988

Impairment in right ventricular performance after left ventricular aneurysm surgery.

To study the effect of operation for left ventricular (LV) aneurysm on right ventricular (RV) performance, we studied 50 patients before operation with right heart catheterization, RV angiography, and radionuclide ventriculography. Forty patients were followed up and underwent the same investigations 10 +/- 4 months after operation. At baseline, regional RV dysfunction was observed in 89% of the patients whereas global RV dysfunction was present in approximately a third. After operation, no changes in RV regional dysfunction or RV pressures were observed. However, a significant increase in RV end-diastolic (p less than 0.03) and end-systolic volume indices (p less than 0.02) along with a significant decrease in resting and exercise RV ejection fractions (p less than 0.05) was found. We were unable to demonstrate any significant relationship between preoperative RV dysfunction and surgical outcome. We conclude that RV dysfunction is common in patients with LV aneurysm. Current techniques of operative intervention for this type of aneurysm seem to be followed by RV dilatation and impairment in RV function.

Adult↗
PubMed1988

Cardiac function in open-chest dogs after left to right ventricular shunting and right coronary artery occlusion.

Patients with acquired ventricular septal defect (VSD) after myocardial infarction have a particularly bad prognosis if right ventricular function is severely impaired. The significance of an ischaemic right ventricular free wall on cardiac function during interventricular shunting was examined in open-chest dogs. An external interventricular shunt could be opened and closed at will, and by occlusion of the right coronary artery (RCA), a part of the right ventricular free wall was rendered ischaemic. Aortic flow decreased by 8 +/- 2% when the shunt was opened in the presence of a normal right ventricle, and by 16 +/- 2% (difference: P less than 0.05) in the presence of right ventricular ischaemia. Aortic flow fell by 19 +/- 3% when the RCA was occluded. Right ventricular dyskinesia was demonstrated after occlusion of RCA, by recording segment lengths in the right ventricular free wall. The dyskinesia was aggravated when the shunt was opened. The left ventricle exerted a 'negative' work on the ischaemic right ventricular free wall. Retention of blood in the right ventricle, with a subsequent decline in left ventricular filling and an almost unchanged interventricular shunting of blood, explain why aortic flow fell more when the shunt was opened in the presence of right ventricular ischaemia.

Animals↗
PubMed1988

Dynamics of the interventricular septum and ventricular free walls during regional ischaemia in open-chest dogs.

The significance of ischaemia of the left ventricular (LV) and right ventricular (RV) free walls for the dynamics of the interventricular septum (IVS) and the right ventricle was examined in open-chest dogs. Left ventricular and RV ischaemia reduced stroke volume similarly, by 11.2 +/- 1.4% and 11.2 +/- 2.4%, respectively. The dynamics of myocardial segment lengths (SL), recorded in the LV and RV free walls and the IVS, differed. During LV ischaemia, end-diastolic SL (EDSL) and systolic shortening (SS) increased in the IVS, whereas SL remained unchanged in the RV free wall. During RV ischaemia, LV EDSL, and SS decreased. Interventricular septum EDSL also decreased, but this reduction was not statistically significant. During blood volume expansion, LV and RV function curves were shifted right, and/or downwards by LV ischaemia, whereas only the RV function curve was shifted downwards and to the right by RV ischaemia. Thus, ischaemia of the LV free wall induces activation of the Frank-Starling mechanism in the interventricular septum and a deterioration of right ventricular performance.

Animals↗
PubMed1988

Risk factors of morbidity and mortality in surgically treated chronic aortic valvular heart disease.

A cohort of 617 patients underwent aortic valve replacement (AVR) the median follow-up time was 3.4 years with a range (0-7.8) years. The incidence of early mortality was 5.0% and the five years survival (77.9 +/- 1.9)%. Risk factors of early mortality and morbidity (Low Output Syndrome) occurring the first 31 days after operation were pinpointed. Another analysis was done to estimate independent predictors of late premature death from all causes, and from specific causes (cardiac related, sudden cardiac). One of the major late morbid events was the appearance of systemic emboli. Its rate was 1.4% pats. Year. Its risk factors were presence of pure aortic regurgitation and advanced age at operation. The relative survival rate was at 5 years of 87.0% for the total cohort, but for our younger patients (age less than 30 years), we reached 99.4%. Our results suggest more aggressive measures to correct the hazard in AVR, and impose carefulness in comparing quality of AVR from different institutions for mortality and morbidity. Finally the results of AVR are rather palliative than curative except for our younger patients where we reached curability.

Adult↗
PubMed1988

Human heart transplantation. Rejection risk factors.

The present analysis of risk factors in human cardiac transplantation is based on a review of 682 endomyocardial biopsies from 52 grafts in 51 recipients. Acute rejection was diagnosed in 149 biopsies (21.8%). The cumulative 1-year graft survival was 91.5 4%. Four out of seven patients died of irreversible rejection. An univariate analysis using the linearized rate of total rejection showed significantly higher frequency of acute rejection when donor and recipient differed for two HLA-DR antigens compared to zero or one HLA antigen disparity (p less than 0.01), as well as in patients treated with low dose steroids, Cyclosporine (CyA) and Azathioprine (p less than 0.01), compared to treatment with CyA high dose steroids. Other risk factors were graft ischemia extending 60 minutes (p less than 0.05) and patient age exceeding 40 years (p less than 0.05). A multivariate analysis using the competing risk hazard model for irreversible (= lethal) rejection was performed. The presence of two HLA-DR mismatches between donor and recipient was found to be an independent risk factor (relative risk = 8.9), and immunosuppression with CyA and high dose steroids without Azathioprine another (relative risk = 15.3). Potential risk factors such as donor and recipient sex, donor age, prior surgery and time on extracorporeal circulation were not of significant prognostic value neither in regard to rejection nor irreversible rejection.

Azathioprine↗