BORA Community: Faculty of Medicine

Portal and umbilical venous distribution in the human fetus : a longitudinal ultrasound study

Mon, 25 Jun 2007 22:58:59 GMT

Title: Portal and umbilical venous distribution in the human fetus : a longitudinal ultrasound study

Authors: Kessler, Jörg

Abstract: Knowledge of the venous perfusion of the human fetal liver is fragmentary and mainly limited to the umbilical circulation. Current ultrasound technology makes it possible to study blood flow noninvasively and to give new insights into the developmental changes during gestation. AIMS: The general aim of the study was to map the hemodynamics of the venous supply to the fetal liver in humans. In detail: to establish longitudinal reference ranges for ductus venosus flow velocities and waveform indices (paper I), to establish a technique for direct flow measurement in the main portal stem and study its development during the second half of pregnancy (paper II), to assess the flow velocity pattern in the left portal vein (paper III), and to determine the distribution of venous blood supply within the liver and explore the impact of maternal and fetal factors (paper IV). MATERIAL AND METHODS: After informed written consent, 160 women with low-risk pregnancies were recruited to a longitudinal study according to a protocol approved by the Regional Committee for Research Ethics (REK-Vest 04/3837). 4-5 ultrasound examinations, each lasting 60 minutes, were done at four weeks intervals between 20 and 40 weeks of gestation. At each session the inner diameter was measured in: 1. the intraabdominal portion of the umbilical vein, 2. the ductus venosus, 3. the main portal stem, and 4. the left portal vein. In the same vessels, time-averaged maximum flow velocties were measured by Doppler ultrasound. Volume blood flow was calculated and normalised for fetal weight. Mean and percentile curves were constructed using regression analysis and multi-level modelling. The impact of maternal and fetal factors on liver blood flow was investigated by deviance statistics. RESULTS: The established longitudinal reference ranges for ductus venosus flow velocities and waveform indices allow the calculation of conditional percentiles, which are narrower and commonly shifted compared to those of the entire population (Paper I). Blood flow in the main portal stem was pulsatile in 99%. Both diameter and flow velocities doubled during the observation period. Correspondingly, blood flow increased throughout gestation, and so did flow, normalised for fetal weight (Paper II). Flow velocities in the left portal branch increased throughout gestation. We found pulsatile flow in 69%, usually directed towards the right lobe. However, intermittent flow reversal occurred during respiratory movements, and continuous reversal in 8% of the observations close to term (Paper III). Total venous liver flow increased throughout gestation, while normalised flow decreased. Lobe specific flow distribution was stable during gestation directing 60% of the total venous liver flow to the left and 40% to the right lobe. The umbilical vein was the dominating venous blood source, but the portal fraction grew during the last trimester. Venous liver flow and its components were related to birthweight, while lobe specific flow and fractional flow distribution to the lobes were related to pregnancy weight gain (Paper IV). CONCLUSION: We have established longitudinal reference ranges for all components of venous liver supply and the ductus venosus in the human fetus. The reference ranges for ductus venosus velocimetry are appropriate for serial measurements, especially when conditional terms are applied (Paper I). The present established technique of assessing flow in the main portal stem had a high success rate and could be used to show an increasing hemodynamic importance of the main portal stem towards term (Paper II). The umbilico-portal watershed is usually situated in the right liver lobe, but may shift towards the left portal vein even in circulatory uncompromised fetuses. The time-averaged maximum flow velocity is suggested for the evaluation of the umbilico-portal watershed (Paper III). The relationship between venous liver flow and birth weight may indicate a link between liver perfusion and fetal growth. The growing portal fraction of the total venous blood flow signifies the high circulatory priority given to the splanchnic circulation close to term. The relationship between low pregnancy weight gain and the distributional shift in favour of left liver lobe perfusion may be part of an adaptation to various intrauterine environments (Paper IV).

Hereditary Colorectal Cancer

Thu, 12 Apr 2007 22:58:59 GMT

Title: Hereditary Colorectal Cancer

Authors: Stormorken, Astrid Tenden

Investigation of tumour characteristics and treatment strategies in animal models using multiparametric MRI and novel contrast agents

Wed, 20 Jun 2007 22:58:59 GMT

Title: Investigation of tumour characteristics and treatment strategies in animal models using multiparametric MRI and novel contrast agents

Authors: Rygh, Cecilie Brekke

Meeting students’ and supervisors’ expectations : findings from a pilot study done at Centre for International Health, University of Bergen

Wed, 29 Aug 2007 12:34:32 GMT

Title: Meeting students’ and supervisors’ expectations : findings from a pilot study done at Centre for International Health, University of Bergen

Authors: Costea, Daniela Elena

Lifestyle aspects in functional dyspepsia : influence of relaxation and meals on vagal activity, gastric accommodation and symptoms

Mon, 16 Apr 2007 22:58:59 GMT

Title: Lifestyle aspects in functional dyspepsia : influence of relaxation and meals on vagal activity, gastric accommodation and symptoms

Authors: Hjelland, Ina

The use of prosthetic grafts in above-knee femoropopliteal bypass surgery : a clinical study of long-term results and risk factors for failure

Wed, 23 May 2007 22:58:59 GMT

Title: The use of prosthetic grafts in above-knee femoropopliteal bypass surgery : a clinical study of long-term results and risk factors for failure

Authors: Pedersen, Gustav

Abstract: Purpose: The purpose of this study has been to investigate the results of above-knee prosthetic femoropopliteal bypass surgery and to identify risk factors for complications and graft failure. The influence of comorbidity, degree of chronic leg ischaemia, preoperative angiographic run-off score and intraoperative flow measurements on long-term results were investigated. Furthermore, local infections and the outcome of treating occluded prosthetic grafts were studied. Methods: Two-hundred-and-thirty-seven patients (156 men, 81 women) were subjected to 252 above-knee prosthetic femoropopliteal bypass operations at Haukeland University Hospital between Jan 1990 and Dec 2001. One hundred and forty-one graft implantations (129 patients) were done for intermittent claudication and 111 (108 patients) for critical ischaemia. Patient data were prospectively recorded in a database registry. Some data were supplemented from patients records. Occlusion dates, complications, re-operations including amputations, and mortality were also recorded. Patient characteristics, anatomical risk factors and intraoperative flow measurements were analysed for impact on results after surgery. Survival, limb salvage and patency rates were analysed with the Product limit method and illustrated as Kaplan-Meier curves. The risk factors were subjected to univariate analysis using the log rank test for impact on survival, limb salvage and patency rates. Variables approaching significance were included in multivariate analysis performed with the Cox proportional hazard model. Results: Paper I. Surgical site infection was recorded after 7.8 % of the operations and graft infection after 12 %. The risk of developing a local infection was significantly correlated with postoperative lymph fistula. Redo surgery was associated with graft infection. Graft infections caused by Staph. Aur. always warranted surgery, either local revision or graft excision. Paper II. For grafts implanted for intermittent claudication, the assisted primary patency rates were 62 % at 2 years and 44 % at 5 years. The 5-year patency rate for smokers was 24 % versus 67 % for non-smokers (p < 0.01). A previous history of cerebral infarction was significantly associated with reduced graft patency. Preoperative s-creatinine > 125 mmol/L was significantly associated with reduced survival. Paper III. The 30-day mortality rate of patients operated for critical ischaemia was 5.5 %. The 2- and 5-year survival was 72 % and 42 %, whereas the limb salvage rates at 2 and 5 years were 83 % and 73 %, respectively. The 2-year primary patency rate for smokers was 38 % versus 62 % for non-smokers (p = 0.018, hazard ratio 2.18). Smoking and tissue loss were significantly associated with reduced secondary patency. Paper IV. Basal flow measurements were not related to patency. The 2- and 5-year patency rates for grafts with a papaverine flow < 500 ml/min were 48 % and 18 % compared with 66 % and 52 % for grafts with a papaverine flow ≥ 500 ml/min (p = 0.012, hazard ratio 2.6). Two and 5-year patency rates for smokers vs non-smokers were 44 % and 18 % vs 69 % and 54 %. Smoking (p = 0.008, hazard ratio 2.38) and poor run-off score (p = 0.009, hazard ratio 2.38) were independent risk factors for reduced patency. Poor run-off score did not correlate with low values of measured basal or papaverine flow. Paper V. Half the 24 initial procedures to restore patency of occluded grafts originally implanted for critical ischaemia failed within a month. Outcome of second or third-time redo procedures were similar. Primary patency rates of all 55 redo procedures were 32 % at three months, 28 % at six months and 12 % at 12 months. The results of thrombectomy and thrombolysis were similar. Re-opened grafts additionally treated for an underlying anastomotic stenosis had significantly better patency, as compared with re-opened grafts without a pre-existing stenosis (p = 0.027, hazard ratio 2.813). Conclusions: The results regarding survival, limb salvage and patency are comparable to previous reports. The results underline that a long observation period is necessary to achieve full overview of complications and the impact of risk factors. Infectious complications after prosthetic femoropopliteal bypass in the study group were higher than previously reported. The results suggest that a selective approach should be taken towards excision of infected femoropopliteal prostheses according to the clinical presentation of the graft infection and the type of bacteriae involved. A conservative attitude is recommended towards placing a prosthetic graft in the above-knee femoropopliteal position for intermittent claudication. The finding of reduced patency rates in patients with a history of a cerebral insult operated for intermittent claudication need further studies to be verified. Patients with intermittent claudication and renal impairment reveal poor survival, indicating renal impairment as a relative contraindication for surgical treatment. Smokers have inferior patency rates when operated for intermittent claudication as well as for critical ischaemia. Poor angiographic run-off score was also associated with inferior patency rates. These findings indicate that prosthetic femoropopliteal bypass is not very suitable for these groups of patients. Furthermore, the poor secondary patency rates of smokers as well as for patients with tissue loss suggest that these patients may benefit from alternative treatment modalities to re-opening an occluded bypass. A papaverine flow of < 500 ml/min is associated with reduced patency. Additional antithrombotic medication and frequent follow-up may be considered for these grafts. Redo procedures for occluded grafts originally implanted for critical ischaemia are of limited value and cannot be recommended except in cases with a proven graft-related stenosis. Other cases in need of re-intervention should be treated with either a new arterial reconstruction or an amputation. Based on the findings in this study, the following issues must be evaluated when offering an above-knee prosthetic femoropopliteal bypass for chronic limb ischaemia: patient comorbidity, smoking, degree of ischaemia and angiographic runoff score. Careful selection of patients subjected to above-knee prosthetic bypass surgery for chronic ischaemia is mandatory to achieve the optimal gain of the operation.

Assessing medical students’ attitudes towards learning communication skills – which components of attitudes do we measure?

Thu, 29 Mar 2007 22:58:59 GMT

Title: Assessing medical students’ attitudes towards learning communication skills – which components of attitudes do we measure?

Authors: Anvik, Tor; Gude, Tore; Grimstad, Hilde; Baerheim, Anders; Fasmer, Ole B.; Hjortdahl, Per; Holen, Are; Risberg, Terje; Vaglum, Per

Abstract: Background. The Communication Skills Attitudes Scale (CSAS) created by Rees, Sheard and Davies and published in 2002 has been a widely used instrument for measuring medical students' attitudes towards learning communication skills. Earlier studies have shown that the CSAS mainly tests two dimensions of attitudes towards communication; positive attitudes (PAS) and negative attitudes (NAS). The objectives of our study are to explore the attitudes of Norwegian medical students towards learning communication skills, and to compare our findings with reports from other countries. Methods. The CSAS questionnaire was mailed simultaneously to all students (n = 3055) of the four medical schools in Norway in the spring of 2003. Response from 1833 students (60.0%) were analysed by use of SPSS ver.12. Results. A Principal component analysis yielded findings that differ in many respects from those of earlier papers. We found the CSAS to measure three factors. The first factor describes students' feelings about the way communication skills are taught, whereas the second factor describes more fundamental attitudes and values connected to the importance of having communication skills for doctors. The third factor explores whether students feel that good communication skills may help them respecting patients and colleagues. Conclusion. Our findings indicate that in this sample the CSAS measures broader aspects of attitudes towards learning communication skills than the formerly described two-factor model with PAS and NAS. This may turn out to be helpful for monitoring the effect of different teaching strategies on students' attitudes during medical school.

Assessing medical students’ attitudes towards learning communication skills – which components of attitudes do we measure?

Thu, 29 Mar 2007 22:58:59 GMT