Active regulation of cerebral venous tone: simultaneous arterial and venous transcranial Doppler sonography during a Valsalva manoeuvre

The aim of this study was to analyse the cerebral venous outflow in relation to the arterial inflow during a Valsalva manoeuvre (VM). In 19 healthy volunteers (mean age 24.1 +/- 2.6 years), the middle cerebral artery (MCA) and the straight sinus (SRS) were insonated by transcranial Doppler sonography. Simultaneously the arterial blood pressure was recorded using a photoplethysmographic method. Two VM of 10 s length were performed per participant. Tracings of the variables were then transformed to equidistantly re-sampled data. Phases of the VM were analysed regarding the increase of the flow velocities and the latency to the peak. The typical four phases of the VM were also found in the SRS signal. The relative flow velocity (FV) increase was significantly higher in the SRS than in the MCA for all phases, particularly that of phase IV (p < 0.01). Comparison of the time latency of the VM phases of the MCA and SRS only showed a significant difference for phase I (p < 0.01). In particular, there was no significant difference for phase IV (15.8 +/- 0.29 vs. 16.0 +/- 0.28 s). Alterations in venous outflow in phase I are best explained by a cross-sectional change of the lumen of the SRS, while phases II and III are compatible with a Starling resistor. However, the significantly lager venous than the arterial overshoot in phase IV may be explained by the active regulation of the venous tone.

The Influence of Abdominal Pressure on Lower Extremity Venous Pressure and Hemodynamics: A Human In-vivo Model Simulating the Effect of Abdominal Obesity

To demonstrate that abdominal pressure impacts venous flow and pressure characteristics.

Cerebral sinus venous thrombosis in Swiss children

AIMo describe the characteristics of paediatric cerebral sinus venous thrombosis (CSVT) in Switzerland.

A nation-wide initiative against venous thromboembolism

There is a gap between knowledge and recommendations regarding venous thromboembolism (VTE) on the one hand and daily practice on the other. This fact has prompted a Swiss multidisciplinary group consisting of angiologists, haematologists, internists, and emergency medicine and pharmaceutical medicine specialists interested in VTE, the SAMEX group, to set up a series of surveys and studies that give useful insight into the situation in our country. Their projects encompassed prophylactic and therapeutic aspects of VTE, and enrolled over 7000 patients from five academic and 45 non-academic acute care hospitals and fifty-three private practices in Switzerland. This comprehensive Swiss Clinical Study Programme forms the largest database surveying current clinical patterns of VTE management in a representative sample of the Swiss patient population. Overall the programme shows a lack of thromboprophylaxis use in hospitalised at-risk medical patients, particularly in those with cancer, acute heart or respiratory failure and the elderly, as well as under-prescription of extended prophylaxis beyond hospital discharge in patients undergoing major cancer surgery. In regard to VTE treatment, planning of anticoagulation duration, administration of LMWH for cancer-associated thrombosis, and the use of compression therapy for prevention of post-thrombotic syndrome in patients with symptomatic proximal DVT require improvement. In conclusion, this programme highlights insufficient awareness of venous thromboembolic disease in Switzerland, underestimation of its burden and inconsistent application of international consensus statement guidelines regarding prophylaxis and treatment adopted by the Swiss Expert Group.

Techniques for assessing cardiac output and fetal cardiac function

Fetal echocardiography was initially used to diagnose structural heart disease, but recent interest has focused on functional assessment. Effects of extracardiac conditions on the cardiac function such as volume overload (in the recipient in twin-twin transfusion syndrome), a hyperdynamic circulation (arterio-venous malformation), cardiac compression (diaphragmatic hernia, lung tumours) and increased placental resistance (intrauterine growth restriction and placental insufficiency) can be studied by ultrasound and may guide decisions for intervention or delivery. A variety of functional tests can be used, but there is no single clinical standard. For some specific conditions, however, certain tests have shown diagnostic value.

Outcomes of Intravenous Thrombolysis in Posterior Versus Anterior Circulation Stroke

Intravenous thrombolysis is an approved treatment for anterior (ACS) and posterior (PCS) circulation stroke. However, no randomized controlled trial has investigated safety and efficacy of intravenous thrombolysis according to stroke territory, although PCS is assumed to differ from ACS in many ways. We aimed to compare the safety and clinical outcome of intravenous thrombolysis applied to patients with PCS and ACS.

Selective inferior petrosal sinus sampling without venous outflow diversion in the detection of a pituitary adenoma in Cushing's syndrome

Conventional MRI may still be an inaccurate method for the non-invasive detection of a microadenoma in adrenocorticotropin (ACTH)-dependent Cushing's syndrome (CS). Bilateral inferior petrosal sinus sampling (BIPSS) with ovine corticotropin-releasing hormone (oCRH) stimulation is an invasive, but accurate, intervention in the diagnostic armamentarium surrounding CS. Until now, there is a continuous controversial debate regarding lateralization data in detecting a microadenoma. Using BIPSS, we evaluated whether a highly selective placement of microcatheters without diversion of venous outflow might improve detection of pituitary microadenoma.

Predictors of in-hospital mortality in elderly patients with acute venous thrombo-embolism: the SWIss Venous ThromboEmbolism Registry (SWIVTER)

Although acute venous thrombo-embolism (VTE) often afflicts patients with advanced age, the predictors of in-hospital mortality for elderly VTE patients are unknown.

Cardiac troponin testing and the simplified Pulmonary Embolism Severity Index. The SWIss Venous ThromboEmbolism Registry (SWIVTER)

A low simplified Pulmonary Embolism Severity Index (sPESI), defined as age ≤80 years and absence of systemic hypotension, tachycardia, hypoxia, cancer, heart failure, and lung disease, identifies low-risk patients with acute pulmonary embolism (PE). It is unknown whether cardiac troponin testing improves the prediction of clinical outcomes if the sPESI is not low. In the prospective Swiss Venous Thromboembolism Registry, 369 patients with acute PE and a troponin test (conventional troponin T or I, highly sensitive troponin T) were enrolled from 18 hospitals. A positive test result was defined as a troponin level above the manufacturers assay threshold. Among the 106 (29%) patients with low sPESI, the rate of mortality or PE recurrence at 30 days was 1.0%. Among the 263 (71%) patients with high sPESI, 177 (67%) were troponin-negative and 86 (33%) troponin-positive; the rate of mortality or PE recurrence at 30 days was 4.6% vs. 12.8% (p=0.015), respectively. Overall, risk assessment with a troponin test (hazard ratio [HR] 3.39, 95% confidence interval [CI] 1.38-8.37; p=0.008) maintained its prognostic value for mortality or PE recurrence when adjusted for sPESI (HR 5.80, 95%CI 0.76-44.10; p=0.09). The combination of sPESI with a troponin test resulted in a greater area under the receiver-operating characteristic curve (HR 0.72, 95% CI 0.63-0.81) than sPESI alone (HR 0.63, 95% CI 0.57-0.68) (p=0.023). In conclusion, although cardiac troponin testing may not be required in patients with a low sPESI, it adds prognostic value for early death and recurrence for patients with a high sPESI.

Sustained impact of electronic alerts on rate of prophylaxis against venous thromboembolism

Advanced electronic alerts (eAlerts) and computerised physician order entry (CPOE) increase adequate thromboprophylaxis orders among hospitalised medical patients. It remains unclear whether eAlerts maintain their efficacy over time, after withdrawal of continuing medical education (CME) on eAlerts and on thromboprophylaxis indications from the study staff. We analysed 5,317 hospital cases from the University Hospital Zurich during 2006-2009: 1,854 cases from a medical ward with eAlerts (interventiongroup) and 3,463 cases from a surgical ward without eAlerts (controlgroup). In the intervention group, an eAlert with hospital-specific venous thromboembolism (VTE) prevention guidelines was issued in the electronic patient chart 6 hours after admission if no pharmacological or mechanical thromboprophylaxis had been ordered. Data were analysed for three phases: pre-implementation (phase 1), eAlert implementation with CME (phase 2), and post-implementation without CME (phase3). The rates of thromboprophylaxis in the intervention group were 43.4% in phase 1 and 66.7% in phase 2 (p<0.001), and increased further to 73.6% in phase3 (p=0.011). Early thromboprophylaxis orders within 12 hours after admission were more often placed in phase 2 and 3 as compared to phase 1 (67.1% vs. 52.1%, p<0.001). In the surgical control group, the thromboprophylaxis rates in the three phases were 88.6%, 90.7%, 90.6% (p=0.16). Advanced eAlerts may provide sustained efficacy over time, with stable rates of thromboprophylaxis orders among hospitalised medical patients.