Correlations among different platelet aggregation pathways in a group of healthy volunteers

Platelet aggregation is a complicated process mediated by different signaling pathways. As the process is highly complex and apparently redundant, the relationships between these pathways are not yet fully known. The aim of this project was to study the interconnections among seven different aggregation pathways in a group of 53 generally healthy volunteers aged 20 to 66 years. Platelet aggregation was induced with thrombin receptor activating peptide 6 (TRAP), arachidonic acid (AA), platelet activating factor 16 (PAF), ADP, collagen, thromboxane A2 analogue U46619 or ristocetin (platelet agglutination) ex vivo in fasting blood samples according to standardized timetable protocol. Additionally, some samples were pre-treated with known clinically used antiplatelet drugs (vorapaxar, ticagrelor or acetylsalicylic acid (ASA)). Significant correlations among all used inducers were detected (Pearson correlation coefficients (rP): 0.3 to 0.85). Of all the triggers, AA showed to be the best predictor of the response to other inducers with rP ranging from 0.66 to 0.85. Interestingly, the antiplatelet response to ticagrelor strongly predicted the response to unrelated drug vorapaxar (rP = 0.71). Our results indicate that a response to one inducer can predict the response for other triggers or even to an antiplatelet drug. These data are useful for future testing but should be also confirmed in patients.

The impact of prehabilitation on outcomes in frail and high-risk patients undergoing major abdominal surgery: A systematic review and meta-analysis

BACKGROUND & AIMS

Prehabilitation comprises multidisciplinary preoperative interventions including exercise, nutritional optimisation and psychological preparation aimed at improving surgical outcomes. The aim of this systematic review and meta-analysis was to determine the impact of prehabilitation on postoperative outcomes in frail and high-risk patients undergoing major abdominal surgery.

METHODS

Embase, Medline, CINAHAL and Cochrane databases were searched from January 2010 to January 2023 for randomised clinical trials (RCTs) and observational studies evaluating unimodal (exercise) or multimodal prehabilitation programmes. Meta-analysis was limited to length of stay (primary end point), severe postoperative complications (Clavien-Dindo Classification ≥ Grade 3) and the 6-minute walk test (6MWT). The analysis was performed using RevMan v5.4 software.

RESULTS

Sixteen studies (6 RCTs, 10 observational) reporting on 3339 patients (1468 prehabilitation group, 1871 control group) were included. The median (interquartile range) age was 74.0 (71.0-78.4) years. Multimodal prehabilitation was applied in fifteen studies and unimodal in one. Meta-analysis of nine studies showed a reduction in hospital length of stay (weighted mean difference -1.07 days, 95 % CI -1.60 to -0.53 days, P < 0.0001, I2 = 19 %). Ten studies addressed severe complications and a meta-analysis suggested a decline in occurrence by up to 44 % (odds ratio 0.56, 95 % CI 0.37 to 0.82, P < 0.004, I2 = 51 %). Four studies provided data on preoperative 6MWT. The pooled weighted mean difference was 40.1 m (95 % CI 32.7 to 47.6 m, P < 0.00001, I2 = 24 %), favouring prehabilitation.

CONCLUSION

Given the significant impact on shortening length of stay and reducing severe complications, prehabilitation should be encouraged in frail, older and high-risk adult patients undergoing major abdominal surgery.

Head-to-head ex vivo comparison of clinically used direct anticoagulant drugs

An imbalance in coagulation is associated with cardiovascular events. For prevention and treatment, anticoagulants, currently mainly xabans and gatrans, are used. The purpose of the present study was to provide a head-to-head comparison since there are no studies directly evaluating these novel anticoagulants. An additional aim was to find whether selected anthropological and biochemical factors can affect their anticoagulant properties as they are used in fixed doses. In this cross-sectional study, blood from 50 generally healthy donors was collected, and coagulation responses to dabigatran, argatroban, rivaroxaban, and apixaban, at a concentration of 1 μM, were analyzed. Heparin was used as a positive control. Prothrombin time (PT) expressed as international normalized ratio (INR) and activated partial thromboplastin time (aPTT) were measured and compared. Rivaroxaban was the most active according to PT/INR while argatroban according to aPTT. The ex vivo anticoagulant effect measured by INR correlated inversely with body mass index (BMI) in all four anticoagulants tested. Shortening of aPTT was associated with higher cholesterol and triglyceride levels. No sex-related differences were observed in response to the anticoagulant treatments. As this was an ex vivo study and pharmacokinetic factors were not included, the influence of BMI is of high therapeutic importance.

Prehabilitation: high-quality evidence is still required

Prehabilitation comprises multidisciplinary healthcare interventions, including exercise, nutritional optimisation, and psychological preparation, which aim to dampen the metabolic response to surgery, shorten the period of recovery, reduce complications, and improve the quality of recovery and quality of life. This editorial evaluates the potential benefits and limitations of and barriers to prehabilitation in surgical patients. The results of several randomised clinical trials and meta-analyses on prehabilitation show differing results, and the strength of the evidence is relatively weak. Heterogeneity in patient populations, interventions, and outcome measures, with a wide range for compliance, contribute to this variation. Evidence could be strengthened by the conduct of large-scale, appropriately powered multicentre trials that have unequivocal clinically relevant and patient-centric endpoints. Studies on prehabilitation should concentrate on recruiting patients who are frail and at high risk. Interventions should be multimodal and exercise regimens should be tailored to each patient's ability with longitudinal measurements of impact.

The Antiplatelet Effect of 4-Methylcatechol in a Real Population Sample and Determination of the Mechanism of Action

A polyphenol-rich diet has beneficial effects on cardiovascular health. However, dietary polyphenols generally have low bioavailability and reach low plasma concentrations. Small phenolic metabolites of these compounds formed by human microbiota are much more easily absorbable and could be responsible for this effect. One of these metabolites, 4-methylcatechol (4-MC), was suggested to be a potent anti-platelet compound. The effect of 4-MC was tested ex vivo in a group of 53 generally healthy donors using impedance blood aggregometry. The mechanism of action of this compound was also investigated by employing various aggregation inducers/inhibitors and a combination of aggregometry and enzyme linked immunosorbent assay (ELISA) methods. 4-MC was confirmed to be more potent than acetylsalicylic acid on both arachidonic acid and collagen-triggered platelet aggregation. Its clinically relevant effect was found even at a concentration of 10 μM. Mechanistic studies showed that 4-MC is able to block platelet aggregation caused by the stimulation of different pathways (receptors for the von Willebrand factor and platelet-activating factor, glycoprotein IIb/IIIa, protein kinase C, intracellular calcium elevation). The major mechanism was defined as interference with cyclooxygenase-thromboxane synthase coupling. This study confirmed the strong antiplatelet potential of 4-MC in a group of healthy donors and defined its mechanism of action.

Sex-Related Differences in Platelet Aggregation: A Literature Review Supplemented with Local Data from a Group of Generally Healthy Individuals

The process of platelet aggregation is often influenced by several factors including sex and age. A literature review confirmed the existence of sex-related differences in platelet aggregation. Although 68 out of 78 papers found such differences, there are still some controversies regarding these differences, which can be due to multiple factors (age, trigger, concomitant disease, sample handling, etc.). These outcomes are discussed in line with novel results obtained from a local study, in which blood samples from a total of 53 overall healthy women and men with ages ranging from 20 to 66 years were collected. Aggregation was induced with seven different triggers (ristocetin, thrombin receptor activating peptide 6 [TRAP-6], arachidonic acid [AA], platelet-activating factor 16 [PAF-16], ADP, collagen, or thromboxane A₂ analog U-46619) ex vivo. In addition, three FDA-approved antiplatelet drugs (vorapaxar, ticagrelor, or acetylsalicylic acid [ASA]) were also tested. In general, women had higher aggregation responses to some agonists (ADP, TRAP), as well as lower benefit from inhibitors (ASA, vorapaxar). The aggregatory responses to AA and TRAP decreased with age in both sexes, while responses to ADP, U-46619, and PAF were affected by age only in women. In conclusion, more studies are needed to decipher the biological importance of sex-related differences in platelet aggregation in part to enable personalized antiplatelet treatment.

The Impact of Preoperative Immune Modulating Nutrition on Outcomes in Patients Undergoing Surgery for Gastrointestinal Cancer: A Systematic Review and Meta-analysis

OBJECTIVE

To define the influence of preoperative immune modulating nutrition (IMN) on postoperative outcomes in patients undergoing surgery for gastrointestinal cancer.

BACKGROUND

Although studies have shown that perioperative IMN may reduce postoperative infectious complications, many of these have included patients with benign and malignant disease, and the optimal timing of such an intervention is not clear.

METHODS

The Embase, Medline, and Cochrane databases were searched from 2000 to 2018, for prospective randomized controlled trials evaluating preoperative oral or enteral IMN in patients undergoing surgery for gastrointestinal cancer. The primary endpoint was the development of postoperative infectious complications. Secondary endpoints included postoperative noninfectious complications, length of stay, and up to 30-day mortality. The analysis was performed using RevMan v5.3 software.

RESULTS

Sixteen studies reporting on 1387 patients (715 IMN group, 672 control group) were included. Six of the included studies reported on a mixed population of patients undergoing all gastrointestinal cancer surgery. Of the remaining, 4 investigated IMN in colorectal cancer surgery, 2 in pancreatic surgery, and another 2 in patients undergoing surgery for gastric cancer. There was 1 study each on liver and esophageal cancer. The formulation of nutrition used in all studies in the treated patients was Impact (Novartis/Nestlé), which contains ω-3 fatty acids, arginine, and nucleotides. Preoperative IMN in patients undergoing surgery for gastrointestinal cancer reduced infectious complications [odds ratio (OR) 0.52, 95% confidence interval (CI) 0.38-0.71, P < 0.0001, I = 16%, n = 1387] and length of hospital stay (weighted mean difference -1.57 days, 95% CI -2.48 to -0.66, P = 0.0007, I = 34%, n = 995) when compared with control (isocaloric isonitrogeneous feed or normal diet). It, however, did not affect noninfectious complications (OR 0.98, 95% CI 0.73-1.33, P = 0.91, I = 0%, n = 1303) or mortality (OR 0.55, 95% CI 0.18-1.68, P = 0.29, I = 0%, n = 955).

CONCLUSION

Given the significant impact on infectious complications and a tendency to shorten length of stay, preoperative IMN should be encouraged in routine practice in patients undergoing surgery for gastrointestinal cancer.

In-vivo interspecies transmission of carbapenemase KPC in a long-term treated female patient

The increasing incidence of multiresistant bacterial strains is currently a serious health concern. These pathogens are often the cause of nosocomial infections with limited treatment options and high fatality rates. A case report is presented of an uncommon detection of four different species (Citrobacter freundii, Klebsiella pneumoniae, Escherichia coli, and Morganella morganii) producing the same type of carbapenemase, KPC-2, in a female patient during her complicated long-term hospital stay. Resistance was probably spread to other species by horizontal transmission of plasmids carrying the blaKPC-2 genes. The implementation of strict anti-epidemic measures prevented further spread of these carbapenem-resistant bacteria.