Haemostatic and fibrinolytic changes in obese subjects undergoing bariatric surgery: the effect of different surgical procedures

Impact of Short-Term Weight Loss on Hemostasis and Thrombosis after Bariatric Surgery

Introduction

Obesity causes thrombophilia and many coagulation problems related to slowing the capillary flow. We aimed to evaluate rapid weight loss outcomes in the early period after bariatric surgery on the coagulation system. Materials and Method. A prospective study enrolled 28 patients with a BMI > 40 kg/m2 who underwent bariatric surgery. Preoperative and postoperative (first and third months) demographic criteria-such as age, gender, weight, height, and alcohol and tobacco use, and biochemical parameters such as PLT, PT, aPTT, INR, bleeding time, coagulation time, fibrinogen, D-dimer, albumin, calcium, ionized calcium, vitamin D, and PTH-were analyzed.

Results

We found that both bleeding and thrombotic parameters increase in early-slowing surgery. The first-month platelet levels were significantly different from the preoperative values (p < 0.001). The prothrombin time in the first (p < 0.001) and third months (p < 0.009) was also comparable. The PTT in the first month was higher than in the preoperative period (p < 0.011). INR in the first month (p < 0.001) was higher than that in the preoperative period and the third month (p = 0.007) value was higher than in the first month. In terms of fibrinogen levels, all parameters indicated statistical significance within each other; preoperative to the first month (p < 0.001), the first month to the third month (p < 0.016). Third-month D-dimer levels were lower than the first month's values (p = 0.032).

Conclusion

Thromboembolic events have crucial importance in the converse scenario of haemorrhagic diathesis during the first months of bariatric surgery. Vitamin support and antithrombotic agents may be recommended in the early postoperative period.

Effect of bariatric surgery on carotid intima-media thickness: A meta-analysis based on observational studies

Objective

This meta-analysis aimed to investigate the effect of bariatric surgery on CIMT in people with obesity.

Methods

PubMed, Web of Science, Embase, and the Cochrane Library were searched for observational studies assessing the effect of bariatric surgery on CIMT from inception to August 2022. Mean difference (MD) and 95% confidence intervals were calculated to assess CIMT.

Results

A total of 23 studies, including 1,349 participants, were eligible to participate in this meta-analysis. The results revealed that CIMT was significantly decreased at 6 months, 12 months, and more than 18 months after bariatric surgery compared with baseline (6 months: MD = 0.09; P < 0.01; 12 months: MD = 0.12; P < 0.01; more than 18 months: MD = 0.14; P = 0.02). Meanwhile, laparoscopic Roux-en-Y gastric bypass (LRYGB) seemed to be more effective than laparoscopic sleeve gastrectomy (LSG) in lowering CIMT in terms of the type of surgery (LSG: MD = 0.11; P < 0.01; LRYGB: MD = 0.14; P < 0.01). Lastly, the benefits of bariatric surgery on CIMT was independent of gender (Male: MD = 0.06; P = 0.04; Female: MD = 0.08; P = 0.03).

Conclusions

Bariatric surgery is consistently effective in reducing CIMT in people with obesity.

Medical and Surgical Obesity Treatments and Atherosclerosis: Mechanisms beyond Typical Risk Factors

PURPOSE OF REVIEW

This study aims to discuss the mechanisms by which GLP-1 agonists and bariatric surgery improve cardiovascular outcomes in severely obese patients.

RECENT FINDINGS

Recent studies have demonstrated that both GLP-1 agonist use and bariatric surgery reduce adverse cardiovascular outcomes. Improvements in traditional atherosclerosis risk factors in association with weight loss likely contribute, but weight loss-independent mechanisms are also suggested to have roles. We review the clinical and preclinical evidence base for cardiovascular benefit of LP-1 agonists and bariatric surgery beyond traditional risk factors, including improvements in endothelial function, direct impacts on atherosclerotic plaques, and anti-inflammatory effects.

Bariatric Surgery in Obesity: Effects on Gut Microbiota and Micronutrient Status

Obesity is associated with reduced gut microbial diversity and a high rate of micronutrient deficiency. Bariatric surgery, the therapy of choice for severe obesity, produces sustained weight loss and improvements in obesity-related comorbidities. Also, it significantly alters the gut microbiota (GM) composition and function, which might have an important impact on the micronutrient status as GM is able to synthesize certain vitamins, such as riboflavin, folate, B12, or vitamin K2. However, recent data have reported that GM is not fully restored after bariatric surgery; therefore, manipulation of GM through probiotics represents a promising therapeutic approach in bariatric patients. In this review, we discuss the latest evidence concerning the relationship between obesity, GM and micronutrients, the impact of bariatric surgery on GM in relation with micronutrients equilibrium, and the importance of the probiotics' supplementation in obese patients submitted to surgical treatment.

Longitudinal Comparison of the Effect of Gastric Bypass to Sleeve Gastrectomy on Liver Function in a Bariatric Cohort: Tehran Obesity Treatment Study (TOTS)

BACKGROUND

Patients with morbid obesity commonly have fatty liver disease and elevated liver enzymes. While surgery effectively induces weight loss, bariatric techniques may differ regarding liver function improvement.

OBJECTIVES

To evaluate and compare the trends of liver function recovery after gastric bypass surgery (GB) with sleeve gastrectomy (SG).

SETTING

University hospitals, Iran.

METHODS

Adult bariatric candidates without a history of alcohol consumption or other etiologies of liver disease who underwent SG (n = 682) or GB (n = 355) were included. Trends of weight loss parameters and alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP) at 0, 6 (in 90.4%), 12 (in 83.5%), and 24 months (in 67.1%) were compared using generalized estimating equations method.

RESULTS

Overall, 1037 patients with mean age of 38.4 ± 11.2 and mean body mass index of 44.9 ± 6.2 kg/m² were analyzed. Seventy-eight percent of patients had fatty liver by ultrasound. Both GB and SG patients lost significant weight, with GB patients having a higher percentage of excess weight loss at 24 months (80.1% vs. 75.9%, P_{between-group} = .008). SG patients showed more favorable trends in liver chemistries with significantly lower ALT at 12 months and AST and ALP levels at 6 and 12 months. However, the two groups were comparable at 24 months. Significantly more GB patients developed high ALT at 6 and high AST at 6 and 12 months. Undergoing GB was associated with smaller 0-12-month changes in ALT, AST, and ALP.

CONCLUSIONS

Bariatric surgery resulted in improvement in liver function parameters, with SG showing advantages over GB in the first postoperative year.

Thromboelastography Values Remain Hypercoagulative 6 Months After Obesity Surgery: a Pilot Study

PURPOSE

Obesity causes a prothrombotic state and is known as a predisposing factor for thromboembolic events. In this pilot study, we assessed the impact of surgery for obesity and the subsequent weight loss on blood coagulation using traditional coagulation tests and thromboelastography (TEG).

MATERIAL AND METHODS

We studied blood samples from 18 patients receiving bariatric surgery. Besides traditional blood coagulation tests and high-sensitivity C-reactive protein (hsCRP) as a marker of inflammation, the TEG parameters reaction time (R), kinetics time (K), angle (α), maximum amplitude (MA), clot strength (G), and lysis percent at 60 min (LY60) were determined preoperatively and on the first postoperative day and 6 months after surgery.

RESULTS

Altogether, 54 samples were analyzed. The median MA (71.3 mm), G (12,403.3 d/sc), and hsCRP (3.5 mg/l) were elevated preoperatively. The median hsCRP further increased on the first day postoperatively, but declined to the normal range 6 months after surgery, while MA and G remained elevated. In traditional coagulation tests, there was an increase in median fibrinogen and D-dimer postoperatively. D-dimer normalized (0.4 mg/l) during the study period, while the fibrinogen level (4.1 g/l) remained above the upper limit of normal.

CONCLUSIONS

Measured by TEG, patients receiving bariatric surgery have hemostatic abnormalities indicating hypercoagulation at the 6-month follow-up visit, suggesting an elevated risk for thromboembolic events for at least 6 months after surgery.

Bariatric surgery in morbidly obese individuals affects plasma levels of protein C and thrombomodulin

Obesity is associated with a prothrombotic milieu and an increased risk for thrombotic events. Bariatric surgery is the most effective treatment for obesity resulting in dramatic weight loss and reduced inflammation and extrinsic coagulation pathway activation. Blood samples were drawn from 60 patients undergoing Roux-en-Y gastric bypass surgery before and 1 year after the intervention. Protein C (PC), activated PC (APC), soluble thrombomodulin (TM), soluble E-selectin (E-Sel), prothrombin time (PT) and activated partial thromboplastin time (aPTT) were evaluated. Both PC (187.4 ± 64.5% before surgery to 118.1 ± 48% 1 year after surgery, p < 0.001) and APC (138.7 ± 64.4% before surgery to 69.1 ± 65.7% after surgery, p < 0.001) were reduced following surgical intervention. TM showed a similar behavior with a reduction of soluble TM after the procedure from 5.7 ± 2.6 to 3.2 ± 1.4 ng/ml (p < 0.001). Similarly, soluble E-Sel was reduced after surgery from 26.6 ± 12.7 to 5.5 ± 4.1 ng/ml (p < 0.001). In contrast, aPTT was not shortened but slightly increased from 29.1 ± 4.8 s. before surgery to 31 ± 4.4 s. (p = 0.001) after surgery and levels of PT were reduced after surgery to 89.6 ± 15.5% from an initial 97.5 ± 13.5% (p < 0.001). In conclusion, we demonstrate a reduction of PC and APC 1 year after bariatric surgery accompanied by a reduction in soluble TM and soluble E-Sel. The reduction of PC and APC is not paralleled by a reduction but in contrast by a prolongation of aPTT suggesting a compensatory upregulation of PC during obesity. The reduction of TM and E-Sel might hint towards an improved endothelial function in this cohort of patients.

Effects of bariatric surgery on markers of subclinical atherosclerosis and endothelial function: a meta-analysis of literature studies

BACKGROUND/OBJECTIVES

Several studies confirmed a significantly increased carotid intima-media thickness (IMT) and impaired flow-mediated dilation (FMD) and nitrate-mediated dilation (NMD) in obese subjects, but few data are available on the effects of bariatric surgery on these markers of cardiovascular (CV) risk. We performed a meta-analysis of studies evaluating changes in IMT, FMD and NMD in obese patients after bariatric surgery.

METHODS

A systematic search was performed in the PubMed, Web of Science, Scopus and EMBASE databases without any language or publication year restriction. The last search was performed in January 2015. In addition, the reference lists of all retrieved articles were manually reviewed. Prospective studies evaluating the impact of bariatric surgery on the markers of CV risk were included. Changes in IMT, FMD and NMD after bariatric surgery were expressed as mean differences (MD) with pertinent 95% confidence intervals (95% CIs). IMT has been expressed in millimeters (mm); FMD and NMD as percentage (%). Impact of clinical and demographic features on effect size was assessed by meta-regression.

RESULTS

Ten articles (314 obese patients) were included in the analysis. Six studies contained data on IMT (7 data sets; 206 patients), 8 studies on FMD (9 data sets; 269 patients) and 4 on NMD (4 data sets; 149 patients). After bariatric surgery, there was a significant reduction of IMT (MD: -0.17 mm; 95% CI: -0.290, -0.049; P=0.006) and a significant improvement in FMD (MD: 5.65%; 95% CI: 2.87, 8.03; P<0.001), whereas NMD did not change (MD: 2.173%; 95% CI: -0.796, 5.142; P=0.151). Interestingly, percentage of changes in the body mass index were associated with changes in IMT (Z=11.52, P<0.001), FMD (Z=-4.26, P<0.001) and NMD (Z=-3.81, P<0.001).

CONCLUSIONS

Despite heterogeneity among studies, bariatric surgery is associated with improvement of subclinical atherosclerosis and endothelial function. These effects may significantly contribute to the reduction of the CV risk after bariatric surgery.