Long-term outcome of open surgery in CVI patients concerning postoperative complications, perioperative hemodynamics and clinical efficacy, Part II1

BACKGROUND

Chronic venous disease (CVD) is extremely common worldwide with prevalence increasing with age. It is associated with a reduced quality of life, particularly in relation to pain, physical function and mobility. Symptomatic chronic venous insufficiency (CVI) with venous ulcer at its' endpoint, indicates interventional surgery to cure venous reflux therewith promoting wound healing and preventing recurrence. In this retrospective, single-centre, consecutive case-control study in a single patient population of a university clinic in northern Germany a holistic evaluation of varicose vein surgeries has been undertaken. Part I covered postoperative complications in relation to co-morbidities, co-medication and clinical presentation. Part II of this article presents now the hemodynamic results in relation to the perioperative evolution of CVI specific symptoms.

METHODS

Records of n = 429 (467 extremities) patients from 2009-2013 treated with open surgery were analysed with regards to perioperative hemodynamics. Evolution of CVI symptomology was accessed postoperatively with the help of a questionnaire and patient records in the case of complication development. Venous hemodynamics was analysed in the whole patient population and with regards to complication subgroups: no events (NE), neglectable adverse events (NAE) and non-neglectable adverse events (NNAE).

RESULTS

Postoperatively, patients' CVI-symptoms like pain (p < 0.001), swelling (p < 0.001) and itching (p = 0.003) significantly improved. The venous refill time and venous pump capacity improved significantly after open vein surgery (p < 0.05). Regardless of the development of postoperative complications there was a significant improvement of venous function at 6 weeks- and one-year postoperative in follow-up (p < 0.05). Symptom regression was strongly correlated with hemodynamic improvement.

CONCLUSION

A significant improvement of patients' symptoms was achieved by means of open-surgery, regardless of postoperative complication development. This was in accordance with the improvement of venous hemodynamics. A strong correlation between symptom regression and improvement in venous hemodynamics could be proven.

Practical identifiability and uncertainty quantification of a pulsatile cardiovascular model

Mathematical models are essential tools to study how the cardiovascular system maintains homeostasis. The utility of such models is limited by the accuracy of their predictions, which can be determined by uncertainty quantification (UQ). A challenge associated with the use of UQ is that many published methods assume that the underlying model is identifiable (e.g. that a one-to-one mapping exists from the parameter space to the model output). In this study we present a novel workflow to calibrate a lumped-parameter model to left ventricular pressure and volume time series data. Key steps include using (1) literature and available data to determine nominal parameter values; (2) sensitivity analysis and subset selection to determine a set of identifiable parameters; (3) optimization to find a point estimate for identifiable parameters; and (4) frequentist and Bayesian UQ calculations to assess the predictive capability of the model. Our results show that it is possible to determine 5 identifiable model parameters that can be estimated to our experimental data from three rats, and that computed UQ intervals capture the measurement and model error.

Die kontralaterale doppelte Transpositionslappenplastik

Das Prinzip der einfachen Transpositionslappenplastik (TLP) (Synonym: Schwenklappenplastik) besteht darin, dass in der unmittelbaren Umgebung eines Hautdefektes ein gestielter Lappen mit axialer oder randomisierter Gefäßversorgung generiert und durch eine geringfügige Drehbewegung an seiner Basis über eine dazwischenliegende Zone von normaler Haut in den Defekt eingeschwenkt wird. Häufig erwähnte Varianten der einfachen Transpositionslappenplastik sind die Rhomboidplastiken nach Limberg und Dufourmentel sowie die unilateralen „bi-lobed“ und „tri-lobed“ Schwenklappen 1 2 3 4 5 6. Die kontralaterale doppelte TLP findet hingegen in der Literatur nur sehr selten Erwähnung 4.

Outcomes from the first multidrug-resistant tuberculosis programme in Kenya

SETTING

In March 2006, the first multidrug-resistant tuberculosis (MDR-TB) treatment programme was implemented in Kenya.

OBJECTIVE

To describe patients' treatment outcomes and adverse events.

DESIGN

A retrospective case note review of patients started on MDR-TB treatment at two Médecins Sans Frontières-supported sites and the national referral hospital of Kenya was undertaken. Sites operated an ambulatory model of care. Patients were treated for a minimum of 24 months with at least 4-5 drugs for the intensive phase of treatment, including an injectable agent.

RESULTS

Of 169 patients, 25.6% were human immunodeficiency virus (HIV) positive and 89.3% were culture-positive at baseline. Adverse events occurred in 67.4% of patients: 45.9% had nausea/vomiting, 43.9% electrolyte disturbance, 41.8% dyspepsia and 31.6% hypothyroidism. The median time to culture conversion was 2 months. Treatment outcomes were as follows: 76.6% success, 14.5% deaths, 8.3% lost to follow-up and 0.7% treatment failure. HIV-positive individuals (adjusted odds ratio [aOR] 3.51, 95% confidence interval [CI] 1.12-11.03) and women (aOR 2.73, 95%CI 1.01-7.39) had a higher risk of unfavourable outcomes, while the risk was lower in those with culture conversion at 6 months (aOR 0.11, 95%CI 0.04-0.32).

CONCLUSION

In Kenya, where an ambulatory model of care is used for MDR-TB treatment, treatment success was high, despite high rates of HIV. Almost half of the patients experienced electrolyte disturbance and one third had hypothyroidism; this supports the view that systematic regular biochemical monitoring is needed in Kenya.

Therapy of ulcus cruris of venous and mixed venous arterial origin with autologous, adult, native progenitor cells from subcutaneous adipose tissue: a prospective clinical pilot study

BACKGROUND

The stromal vascular fraction (SVF) of adipose tissue consists of cellular subpopulations with distinct regenerative potential.

OBJECTIVE

To investigate the regenerative capacities of autologous SVF cells in the treatment of chronic leg ulcers of venous (VLU) and arterial-venous (AVLU) origin.

METHODS

Multimorbid ulcer patients received a singular topical treatment with 9-15 × 10⁶ SVF cells, separated from abdominal lipoaspirates by digestion with collagenase and neutral protease and applied immediately after isolation. The primary endpoints were the change in wound size 12 weeks after treatment and evaluation of adverse events. Secondary endpoints included the time to complete wound epithelialization and change in pain levels. Postoperative wound treatment modalities and treatment of comorbidities were not intensified compared with pre-operative management. Follow-up period was at least 6 months.

RESULTS

Sixteen elderly ulcer patients (seven with VLU, nine with AVLU) were treated as described. All VLU patients (median ulcer size: 48.25 cm² ) and four of nine AVLU patients showed complete epithelialization of the ulcers within 71-174 days. In three patients with large ulcerations on both legs, ulcerations on the non-treated, contralateral leg also epithelialized. Patients reported a considerable rapid decrease in pain intensity by 2.5 points on average on a visual scale from 1 to 5 within the first 2 weeks after treatment. The patients were followed up for 9-44 months (median: 30 months). No severe side-effects were observed.

CONCLUSIONS

The use of SVF cells presents an effective, minimally invasive option for the treatment of VLU and AVLU even in multimorbid patients. In patients with larger predominantly ischaemic AVLU and comorbidities, one-time application of the used amounts of SVF cells was not sufficient in the majority of cases.

Uncertainty Quantification in a Patient-Specific One-Dimensional Arterial Network Model: EnKF-Based Inflow Estimator

Successful clinical use of patient-specific models for cardiovascular dynamics depends on the reliability of the model output in the presence of input uncertainties. For 1D fluid dynamics models of arterial networks, input uncertainties associated with the model output are related to the specification of vessel and network geometry, parameters within the fluid and wall equations, and parameters used to specify inlet and outlet boundary conditions. This study investigates how uncertainty in the flow profile applied at the inlet boundary of a 1D model affects area and pressure predictions at the center of a single vessel. More specifically, this study develops an iterative scheme based on the ensemble Kalman filter (EnKF) to estimate the temporal inflow profile from a prior distribution of curves. The EnKF-based inflow estimator provides a measure of uncertainty in the size and shape of the estimated inflow, which is propagated through the model to determine the corresponding uncertainty in model predictions of area and pressure. Model predictions are compared to ex vivo area and blood pressure measurements in the ascending aorta, the carotid artery, and the femoral artery of a healthy male Merino sheep. Results discuss dynamics obtained using a linear and a nonlinear viscoelastic wall model.

Understanding the controls on deposited fine sediment in the streams of agricultural catchments

Excessive sediment pressure on aquatic habitats is of global concern. A unique dataset, comprising instantaneous measurements of deposited fine sediment in 230 agricultural streams across England and Wales, was analysed in relation to 20 potential explanatory catchment and channel variables. The most effective explanatory variable for the amount of deposited sediment was found to be stream power, calculated for bankfull flow and used to index the capacity of the stream to transport sediment. Both stream power and velocity category were highly significant (p ≪ 0.001), explaining some 57% variation in total fine sediment mass. Modelled sediment pressure, predominantly from agriculture, was marginally significant (p<0.05) and explained a further 1% variation. The relationship was slightly stronger for erosional zones, providing 62% explanation overall. In the case of the deposited surface drape, stream power was again found to be the most effective explanatory variable (p<0.001) but velocity category, baseflow index and modelled sediment pressure were all significant (p<0.01); each provided an additional 2% explanation to an overall 50%. It is suggested that, in general, the study sites were transport-limited and the majority of stream beds were saturated by fine sediment. For sites below saturation, the upper envelope of measured fine sediment mass increased with modelled sediment pressure. The practical implications of these findings are that (i) targets for fine sediment loads need to take into account the ability of streams to transport/retain fine sediment, and (ii) where agricultural mitigation measures are implemented to reduce delivery of sediment, river management to mobilise/remove fines may also be needed in order to effect an improvement in ecological status in cases where streams are already saturated with fines and unlikely to self-cleanse.

[Importance of modern treatment procedures for infected and colonized wounds in dermatology]

In the coming years increasing numbers of patients with chronic ulcers and tumor wounds are to be expected, both of which are typically multifaceted diseases requiring complex and increasingly long-term ambulatory therapy. Therefore, in recent years special medical emphasis has been placed on efficacious therapies with good tolerability and also suitability regarding feasibility for outpatient treatment. Some of these methods, such as cold plasma therapy, extracorporeal shock wave therapy (ESWT), water-filtered infrared therapy (wIRA), electrostimulation (ES) and low level laser therapy (LLLT) have a good chance of success when applied as an adjuvant method in the multimodal treatment concept for patients with recalcitrant wounds. All of these methods have at least indirect antimicrobial properties which can be advantageous in cases of microbial infiltration of wounds. As for all other methods for treating recalcitrant wounds, the promising application of the aforementioned methods requires great expertise in wound healing together with a broad and continuous interdisciplinary diagnostics and therapy (wound center).