A systematic review on ablation techniques for larger saphenous veins in patients with symptomatic superficial venous disease

OBJECTIVE

The aim of this study was to summarize the existing evidence for the treatment of saphenous veins >10 mm in diameter, to determine whether there were vein size limits for treatment modalities, and to determine if there are specific technical considerations for treatment of large veins.

METHODS

We searched the literature for reports of treatment methods and outcomes for patients with large-diameter saphenous veins treated with various ablation methods between 1993 and 2023. These studies were evaluated for the size of the vein determined as "large diameter," type of ablation method, study type, outcomes, adverse events, and any technical considerations noted. A systematic review was conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. The COVIDENCE software was used for full-text screening and data extraction. Three reviewers reviewed the data, and the content expert served as the tiebreaker.

RESULTS

Seventy-one records were identified, of which 24 studies were deemed appropriate for extraction. Most of the studies identified reported outcomes of endovenous thermal ablation modalities. There were fewer studies on non-thermal, non-tumescent techniques, and these studies reported an overall lower occlusion rate compared with endovenous thermal ablation techniques.

CONCLUSIONS

Large head-to-head trials or randomized controlled that compare all the modalities over a long follow-up duration are yet to be performed. In the existing literature, there is considerable heterogeneity in terms of the study size, design, definition of large veins, site of vein measurement, and follow-up periods, making it challenging to make fair comparisons and draw firm conclusions. Currently available evidence supports the use of endothermal ablation techniques for the treatment of veins >10 mm in diameter as they have a more favorable efficacy and safety profile and have a larger body of evidence available compared with non-thermal, non-tumescent techniques or surgery.

How Well Can You Tailor the Charge of Lipid Vesicles?

Knowledge and control of surface charge or potential is important for tailoring colloidal interactions. In this work, we compare widely used zeta potential (ζ) measurements of charged lipid vesicle surface potential to direct measurements using the surface force apparatus (SFA). Our measurements show good agreement between the two techniques. On varying the fraction of anionic lipids dimyristoylphosphatidylserine (DMPS) or dimyristoylphosphatidylglycerol (DMPG) mixed with zwitterionic dimyristoylphosphatidylcholine (DMPC) from 0 to 100 mol % we observed a near-linear increase in membrane surface charge or potential up to 20-30 mol % charged lipids beyond which charge saturation occurred in physiological (high) salt conditions. Similarly, in low salt concentrations, a linear increase in charge/potential was found but only up to ∼5-10 mol % charged lipids beyond which the surface charge or potential leveled off. While a lower degree of ionization is expected due to the lower dielectric constant (ε ∼ 4) of the lipid acyl chain environment, increasing intramembrane electrostatic repulsion between neighboring charged lipid head groups at higher charge loading contributes to charge suppression. Measured potentials in physiological salt solutions were consistent with predictions using the Gouy-Chapman-Stern-Grahame (GCSG) model of the electrical double layer with Langmuir binding of counterions, but in low salt conditions, the model significantly overestimated the surface charge/potential. The much lower ionization in low salt (maximum ∼1-2% of total lipids ionized) instead was consistent with counterion condensation at the bilayer surface which limited the charge that could be obtained. The strong interplay between membrane composition, lipid headgroup ionization, electrolyte concentration, and solution pH complicates exact prediction and tuning of membrane surface charge for applications. However, the theoretical frameworks used here can provide guidelines to understand this interplay and establish a range of achievable potentials for a system and predict the response to triggers like pH and salt concentration changes.

Determination of Fat in Raw and Processed Milks by the Gerber Method: Collaborative Study

The Gerber method is used worldwide as a simple and rapid method for determining fat in raw and processed milks. However, the volume of the test portion used in the method has not been internationally agreed upon. A collaborative study was conducted to evaluate performance of the Gerber method using either a weighed test portion (11.13 g) or by a 10.77 mL test portion delivered by pipet. For each method, laboratories received 10 test samples: 5 raw and 5 pasteurized homogenized milks, 2 of which were blind duplicate pairs. Eleven and 10 laboratories participated in the evaluation of aliquot addition by weight and pipet, respectively. Mojonnier ether extraction (Method 989.05) was used as the reference method. Interlaboratory study statistics were similar between methods of test portion addition and between raw and processed materials; therefore, summary interlaboratory study statistics were pooled. The fat content of milk samples ranged from 0.96 to 5.48%. Absolute reproducibility and repeatability were not affected by fat level, and pooled statistical performance (invalid and outlier data removed) was (g fat/100 g milk) sr = 0.026, sR = 0.047, r = 0.074, and R = 0.132. Relative standard deviations increased with decreasing fat content, and were summarized by fat level: 1–2% fat milk, mean = 1.437, RSDr = 1.809%, RSDR = 3.271%; 2–6% fat milk, mean = 4.156, RSDr = 0.626%, RSDR = 1.131%. Compared with ether extraction, test results by the Gerber method were slightly lower (0.02% fat) using a weighed test portion and significantly lower (0.06% fat) using a 10.77 mL volume addition by pipet. A trend toward underestimating fat content at lower fat concentrations (1–2% fat) was observed with the weighed test portion but not when a pipet was used. The Associate Referee recommends that the Gerber method using a weighed test portion be adopted as First Action with applicability limited to whole milk.

Voluntary wheel running reduces weight gain in mice by decreasing high-fat food consumption

We investigated whether wheel running for just 30 min on 5 days each week, an exercise routine based on recommended levels of physical activity for adults, regulates body weight and food intake in mice. Male C57BL/6 mice were divided into groups and given ad libitum access to high-fat food and standard chow or standard chow only. For 30 min on 5 days each week, mice were treated with an in-cage running wheel which was either open to allow voluntary exercise or locked and could not rotate for control. Wheel running reduced weight gain and fat mass among mice fed high-fat food and standard chow, but not mice fed standard chow only. Wheel running decreased high-fat food consumption. Standard chow intake was unchanged. Mice provided with a locked running wheel but pair-fed the same amount of food as wheel running mice also displayed reduced weight gain and fat mass. We conclude that voluntary wheel running for 30 min on 5 days each week reduced weight gain and fat mass in mice by preferentially decreasing high-fat food intake. This model of voluntary wheel running can be used to investigate mechanisms underlying the benefits of exercise on body weight and food intake, informing obesity intervention strategies for humans.

Mental and physical health of spouse caregivers: the role of personality

Although personal resources of caregivers, such as coping skills and social support, have been shown to be important in understanding caregiver stress and health outcomes, personality traits have not previously been considered. The purpose of this study was to examine the association between the personality traits of neuroticism and dispositional optimism and mental and physical health outcomes. It was predicted that personality would have direct effects, and indirect effects through perceived stress, on health outcomes. Participants were spouse caregivers of patients diagnosed with Alzheimer's disease. Results showed that neuroticism and optimism were significantly related to mental and physical health. Furthermore, neuroticism had significant direct effects on all of the health outcomes, and substantial indirect effects, through perceived stress, on mental health outcomes. Optimism showed stronger indirect than direct effects on all health outcomes. These findings demonstrate the importance of including personality of the caregiver in theoretical and empirical models of the caregiving process.

Mental and physical health of spouse caregivers: The role of personality

Although personal resources of caregivers, such as coping skills and social support, have been shown to be important in understanding caregiver stress and health outcomes, personality traits have not previously been considered. The purpose of this study was to examine the association between the personality traits of neuroticism and dispositional optimism and mental and physical health outcomes. It was predicted that personality would have direct effects, and indirect effects through perceived stress, on health outcomes. Participants were spouse caregivers of patients diagnosed with Alzheimer's disease. Results showed that neuroticism and optimism were significantly related to mental and physical health. Furthermore, neuroticism had significant direct effects on all of the health outcomes, and substantial indirect effects, through perceived stress, on mental health outcomes. Optimism showed stronger indirect than direct effects on all health outcomes. These findings demonstrate the importance of including personality of the caregiver in theoretical and empirical models of the caregiving process.