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Biomedical subjects

O Geiran

Publications and source records attributed to O Geiran.

At least 19 recordsLinked to original sources
PubMed1992

Hemodynamic evaluation of the CarboMedics prosthetic heart valve in the aortic position: comparison of noninvasive and invasive techniques.

Seventy-three patients with a CarboMedics aortic bileaflet valve prosthesis were examined by Doppler ultrasonography, and 27 of them were also assessed by transseptal catheterization. The ultrasonic mean systolic gradient was 17.1 +/- 5.6 mm Hg for valve size 19 mm, falling gradually with increasing valve size to 6.8 +/- 2.5 mm Hg for size 27 mm. The catheter mean systolic gradient was consistently smaller than the ultrasonic gradient (4.3 +/- 4.8 mm Hg), but Tobit regression analysis showed a significant association between the two methods. In all patients both methods revealed negligible to small amounts of retrograde leakage, which is assumed to be a normal finding for this valve. The effective flow areas of the valves calculated from the ultrasonic data were similar to the in vitro calculated flow areas. The hemodynamic potential of this valve is therefore completely utilized in vivo. The effective orifice area corrected for body surface area increased with increasing valve size, which demonstrates a moderate valve-patient mismatch.

Adult↗
PubMed1992

Single lung transplantation. Surgical experiences with the first seven patients.

Seven single lung transplants are reported. The patients were severely disabled and oxygen dependent below sixty years of age with a poor prognosis. Diagnosis were alfa 1-antitrypsin deficiency (3), sarcoidosis (3) and idiopathic emphysema (1). Multiorgan-harvesting including six hearts, was performed in local or distant hospitals (3). Partial cardiopulmonary bypass simplified transplantation. The surgical procedure was modified with a direct transpericardial approach. Soft tissue wrapping by a vascularized pedicle secured the bronchial anastomosis. The four drug immunosuppressive regimen included cyclosporin A, azathioprine, steroids and antithymocyte globulin. Primary graft function was excellent. Six patients survived the postoperative period and are alive 5-19 months post transplant. Transbronchial biopsies and lung function studies have been helpful in detecting pulmonary rejections. Patient rehabilitation is satisfactory in most patients with improvement in physiologic parameters.

Adult↗
PubMed1992

Morbidity risk factors in human cardiac transplantation. Histoincompatibility and protracted graft ischemia entail high risk of rejection and infection.

Data from the first 103 human heart transplantations performed on 100 recipients (aged 14-62 years) at a single center from November 1983 to January 1990 were analyzed in order to detect morbidity-causing risk factors. Cumulative one- and five-year graft survival was 82% and 68%. Multivariate analysis revealed three independent risk factors for early rejection, viz. HLA-DR and HLA-B mismatches and no prior cardiac surgery. Graft ischemic time exceeding 71 min was an independent risk factor for rejection, especially for moderate or severe events, and for infection. HLA-DR mismatch was an independent risk factor for moderate and severe rejection events and for infections. Finally, patients operated on because of end-stage ischemic heart disease were at significantly higher risk of rejection than those with other cardiac disorders. The study has several implications: Prospective tissue typing for cardiac transplantation and selection of donors may have an impact on graft function: Damage to the graft by prolonged ischemia may be reduced by improved organ preservation.

Adolescent↗
PubMed1991

[Gastrointestinal cytomegalovirus infection in patients with heart transplants].

Cytomegalovirus (CMV) infection is a major cause of morbidity in organ transplant recipients. Gastrointestinal CMV disease is a serious and potentially lethal complication requiring treatment with antiviral agents. The symptoms and endoscopic findings are nonspecific. The diagnosis may be decided by histological examination, since CMV inclusions can be verified immunohistochemically in routine sections. In a series of 132 heart transplant recipients, 26 developed CMV-infection. Three of these patients had serious gastrointestinal disease. This report describes the patients with gastrointestinal CMV infection, and briefly discusses symptomatology, diagnostic considerations and suggested treatment.

Adult↗
PubMed1991

[Results of 6 1/2 years of heart transplantation at Rikshospitalet].

We discuss our experience from 6 1/2 years of orthotopic heart transplantation at Rikshospitalet (the National Hospital). 112 grafts were performed on 109 patients (19 women and 90 men), mean age 47 years (range 14-63). In the first nine patients the immunosuppressive regimen consisted of cyclosporine A and prednisolone, and in the last 100 azathioprine was added (triple medication). There was no operative mortality. 21 patients died, giving an 81% cumulative survival, with a significantly better prognosis among those who received triple immunosuppressive regimen. The main complications were rejection, infection and arrhythmia. Since our main problem was rejection it is concluded that careful supervision, concentrated on as few cardiologists as possible, and a liberal indication for myocardial biopsy, are decisive for the prognosis.

Adolescent↗
PubMed1991

[Single lung transplantation as treatment of terminal lung diseases].

The article describes the first cases of single lung transplantation in Norway. The indication for surgery was end-stage pulmonary disease (1 sarcoidosis, 2 emphysema) in three severely disabled patients requiring administration of oxygen. The operation necessitated cardiopulmonary bypass in all patients. Primary graft function was excellent. Epidural analgesia, peripheral pulse oxymetry and continuous monitoring of mixed venous oxygen saturation aided early extubation. The initial postoperative course with a four drug immunosuppressive regimen has been encouraging. Rejection is monitored by clinical examination, chest x-ray, serial pulmonary function tests and transbronchial biopsies.

Adult↗
PubMed1991

Risk factors for total and cause-specific mortality in human cardiac transplantation. Prolonged extracorporeal bypass time: a high risk factor for rejection and infection.

Data from the first 103 human heart transplantations in 100 recipients performed at a single centre from November 1983 to January 1990 were analysed to detect risk factors for overall and cause-specific mortality. Twenty-two patients died. Cumulative 1 year graft survival was 82% and 5 year, 68%. Acute and chronic rejection was the cause of death in 9 patients, disseminated infection in 8 and cancer in 3. One patient died from cerebral haemorrhage and 1 from acute cardiac failure. The mean observation time was 803 days (range: 1-2 308 days). Total follow-up was 226.6 graft years. Risk factors were analysed by univariate and multivariate methods. The type of immunosuppression regimen and recipient age above 50 years were independent risk factors for mortality. Histocompatibility mismatching (HLA-DR) and type of immunosuppression were independent risk factors for lethal rejection and a female recipient was an independent risk factor for lethal infection. Prolonged time on extracorporeal bypass was an independent risk factor for both lethal rejection and infection, and also for overall mortality. The impact of extracorporeal bypass time on rejection and infection is discussed, and the importance of prospective HLA matching in heart transplantation is stressed. The association between recipient female sex and infection remains uncertain.

Adolescent↗
PubMed1991

Haemodynamic effects of heparin during coronary bypass surgery.

Heparin has been suggested as an activator of the plasma kallikrein-kinin system, with possible formation of bradykinin, a potent vasodilator. Haemodynamic effects and changes in the kallikrein-kinin system were studied after heparin- and saline-injections in ten patients undergoing coronary bypass surgery. A moderate decrease in mean arterial pressure was found in all patients in the observation period, but significantly more at 2 and 3 min after heparin-injection compared with saline-injection. None of the other haemodynamic variables measured were significantly different when comparing heparin- to saline-injection. Heparin-injection resulted in significant changes in the kallikrein-kinin system, with a marked increase in spontaneous kallikrein-like activity as the most prominent feature, while no changes were found after saline-injection. Liberation of bradykinin would be expected to give a decrease in systemic vascular resistance with an increase in cardiac output. The results indicate that the plasma kallikrein-kinin system, though apparently activated after heparin-injection, does not contribute significantly to the decrease in arterial pressure in the patients studied.

Blood Pressure↗
PubMed1991

Duration of cardiopulmonary bypass compared with changes in the plasma protease systems.

Forty patients undergoing elective coronary artery bypass grafting were investigated concerning association between duration of cardiopulmonary bypass (CPB) and changes in the plasma protease systems. Spontaneous enzyme activity, proenzymes and functional inhibition capacities in the fibrinolytic, plasma kallikrein-kinin and coagulation systems were measured before, during and after CPB and in the immediate postoperative period. No clear relationship was revealed between changes in the measured variables and the duration of CPB.

Blood Coagulation↗
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↗