Incidence and severity of postthrombotic syndrome after iliofemoral thrombosis - results of the Iliaca-PTS - Registry.

Background: Deep venous thrombosis (DVT) and in particular, iliofemoral thrombosis (IFT) can lead to recurrent thrombosis and postthrombotic syndrome (PTS). Data on the prevalence, predictors and outcome of IFT are scarce. Patients and methods: We retrospectively searched our database of outpatients who had presented with DVT and IFT including the iliac veins from 2014 until 2017. In addition, we performed a prospective registry in a subgroup of patients with IFT. These patients received duplex ultrasound, magnetic resonance venography and measurement of symptom-free walking distance using a standardized treadmill ergometry. The severity of PTS was analyzed using the Villalta-Scale (VS) and quality of life was assessed using the VEINES-QOL/Sym Questionnaire. Results: 847 patients were retrospectively identified with DVT and 19.7% (167/847) of these presented with IFT. 50.9% (85/167) of the IFT-patients agreed to participate in the prospective registry. The majority of these patients (76.5%: 65/85) presented with left-sided IFT. In 53.8% (35/65) May-Thurner syndrome was suspected. 27.1% (23/85) underwent invasive therapy. Moderate or severe PTS (VS ≥ 10) occurred in 10.6% (9/85). The severity of PTS is correlated with a reduced quality of life (ρ (CI 95%) = -0.63 (-0.76; -0.46); p < 0.01). None of the patients presented with a venous ulcer at any time. A high body mass index was a significant predictor (OR (CI 95%) = 1.18 (1.05; 1.33), p = 0.007) for the development of clinically relevant PTS (VS ≥ 10) and venous claudication. Conclusions: Every fifth patient with DVT presented with an IFT. The majority developed left sided IFT. Every 10th patient developed moderate or severe PTS (VS ≥ 10). A high body mass index was predictive for the development of PTS and venous claudication.

Influence of clonidine induced sympathicolysis on anaemia tolerance in anaesthetized pigs.

BACKGROUND: Clonidine effectively decreases perioperative mortality by reducing sympathetic tone. However, application of clonidine might also restrict anaemia tolerance due to impairment of compensatory mechanisms. Therefore, the influence of clonidine induced, short-term sympathicolysis on anaemia tolerance was assessed in anaesthetized pigs. We measured the effect of clonidine on anaemia tolerance and of the potential for macrohemodynamic alterations to constrain the acute anaemia compensatory mechanisms. METHODS: After governmental approval, 14 anaesthetized pigs of either gender (Deutsche Landrasse, weight (mean ± SD) 24.1 ± 2.4 kg) were randomly assigned to intravenous saline or clonidine treatment (bolus: 20 µg · kg-1, continuous infusion: 15 µg · kg-1 · h-1). Thereafter, the animals were hemodiluted by exchange of whole blood for 6 % hydroxyethyl starch (MW 130.000/0.4) until the individual critical haemoglobin concentration (Hbcrit) was reached. Primary outcome parameters were Hbcrit and the exchangeable blood volume (EBV) until Hbcrit was reached. RESULTS: Hbcrit did not differ between both groups (values are median [interquartile range]: saline: 2.2 (2.0-2.5) g · dL-1 vs. clonidine: 2.1 (2.1-2.4) g · dL-1; n.s.). Furthermore, there was no difference in exchangeable blood volume (EBV) between both groups (saline: 88 (76-106) mL · kg-1 vs. clonidine: 92 (85-95) mL · kg-1; n.s.). CONCLUSION: Anaemia tolerance was not affected by clonidine induced sympathicolysis. Consequently, perioperative clonidine administration probably has not to be omitted in view of acute anaemia.

Thrombosis of the inferior vena cava and malignant disease.

BACKGROUND: Inferior vena cava thrombosis (IVCT) is a rare event, and studies detailing its underlying aetiologies are scarce. METHODS: One hundred and forty-one IVCT patients (57% females, median age 47 years) were analysed with a focus on malignancy-related thrombosis and compared with 141 age- and sex-matched control patients with isolated lower-extremity deep vein thrombosis. RESULTS: Malignancies were more prevalent among IVCT patients compared with the control group (39% vs. 7.8%; P<0.001). Malignancy-related IVCT more frequently involved the suprarenal and hepatic segments of the IVC and extended more often to the right atrium than IVCT did in non-cancer patients. Among IVCT patients with malignancies, renal cell carcinoma (38%) and other malignancies of the genitourinary tract (25%) were the most common tumours. Analysis of the underlying pathological mechanisms of malignancy-related thrombosis identified external compression of the IVC by tumour masses in 9 cases (16%), and progression of malignancy into the IVC (so-called "tumour thrombosis") in 24 cases (44%). The remaining 22 cases (40%) were attributed to malignancy-related hypercoagulability and the presence of additional venous thromboembolism risk factors, such as previous surgery, immobilisation, or chemotherapy. CONCLUSIONS: Malignancies substantially contribute to the risk of thrombosis involving the IVC. Tumour invasion, especially in cases of renal cell cancer and malignancy-related hypercoagulability are major triggering factors for thrombogenesis.