Comparison of pathological clotting using haematological, functional and morphological investigations in HIV-positive and HIV-negative patients with deep vein thrombosis

HIV infection and ART use are associated with altered plasma clot characteristics in Black South Africans

BACKGROUND

Human immunodeficiency virus (HIV) and antiretroviral treatment (ART) are both associated with hypercoagulability. Altered clot properties could be a potential mechanism thereof. We aimed to investigate the association of HIV and ART, with fibrinogen and plasma clot properties in a group of Black South Africans.

METHODS

At baseline, 151 newly diagnosed people living with HIV (PLWH) and 176 controls were recruited. Some PLWH subsequently commenced with ARTs (n = 70) while others remained ART-naïve (n = 81). Fibrinogen and clot properties (turbidity assay) were investigated from baseline to 5-year follow-up. A sub-group of 21 women (n = 10 ART-treated; n = 11 ART-naïve) with HIV was systematically selected and matched with 12 controls, and additional clot properties (rheometry, permeability and fibre diameter) were investigated.

RESULTS

Fibrinogen was lower in the HIV groups compared to the controls, while % γ' fibrinogen was higher. PLWH had shorter lag times and lower maximum absorbance than the controls (p<0.05). Their CLTs on the other hand were longer. Most variables increased over time in all groups, but differences in the degree of change over time was observed for lag time (p = 0.024) and permeability (p = 0.03). Participants who commenced with ART had a tendency of delayed clot formation (p = 0.08) and increased clot permeability (p = 0.005).

CONCLUSION

PLWH had lower total fibrinogen concentration and formed less dense clots. They also formed clots that were more difficult to lyse, which likely not resulted from altered clot properties. ART use (NNRTI's) had a moderately protective effect, delaying clot formation, and increasing clot permeability.

Prediction model of deep vein thrombosis risk after lower extremity orthopedic surgery

Purpose

This investigation was conceived to engineer and appraise a pioneering clinical nomogram, crafted to bridge the extant chasm in literature regarding the postoperative risk stratification for deep vein thrombosis (DVT) in the aftermath of lower extremity orthopedic procedures. This novel tool offers a sophisticated and discerning algorithm for risk prediction, heretofore unmet by existing methodologies.

Methods

In this retrospective observational study, clinical records of hospitalized patients who underwent lower extremity orthopedic surgery were collected at the Wuxi TCM Hospital Affiliated to the Nanjing University of Chinese Medicine between Jan 2017 and Oct 2019. The univariate and multivariate analysis with the backward stepwise method was applied to select features for the predictive nomogram. The performance of the nomogram was evaluated with respect to its discriminant capability, calibration ability, and clinical utility.

Result

A total of 5773 in-hospital patients were eligible for the study, with the incidence of deep vein thrombosis being approximately 1 % in this population. Among 31 variables included, 5 of them were identified to be the predictive features in the nomogram, including age, mean corpuscular hemoglobin concentration (MCHC), D-dimer, platelet distribution width (PDW), and thrombin time (TT). The area under the receiver operating characteristic (ROC) curve in the training and validation cohort was 85.9 % (95%CI: 79.96 %-90.04 %) and 85.7 % (95%CI: 78.96 %-90.69 %), respectively. Both the calibration curves and decision curve analysis demonstrated the overall satisfactory performance of the model.

Conclusion

Our groundbreaking nomogram is distinguished by its unparalleled accuracy in discriminative and calibrating functions, complemented by its tangible clinical applicability. This innovative instrument is set to empower clinicians with a robust framework for the accurate forecasting of postoperative DVT, thus facilitating the crafting of bespoke and prompt therapeutic strategies, aligning with the rigorous standards upheld by the most esteemed biomedical journals.

A Case of Deep Venous Thrombosis in an HIV-Infected Patient despite Therapeutic Anticoagulation

Patients with human immunodeficiency virus (HIV) infection have an increased likelihood of venous thromboembolism (VTE) owing to factors such as acquired protein C and S deficiency, antiphospholipid antibody syndrome, and heightened levels of pro-inflammatory cytokines. This case report highlights an exceptionally uncommon occurrence of deep venous thrombosis in an HIV-infected patient receiving a therapeutic dose of enoxaparin. This underscores the need for cautious consideration of the risk of VTE in HIV-infected individuals, even with preventive or therapeutic anticoagulant treatment. Further research is recommended to investigate HIV as a potential risk factor of prophylactic anticoagulation.

Changes in Coagulation and Platelet Reactivity in People with HIV-1 Switching Between Abacavir and Tenofovir

Background:

Several studies have shown an association between abacavir (ABC) and increased risk of myocardial infarction (MI), but the causative mechanism has not been established. Both vascular endothelial inflammation and platelet activation have been proposed as contributing factors.

Objective:

The study aims to investigate the effects of ABC relative to tenofovir disoproxil (TDF) on functional assays of primary and secondary hemostasis and a comprehensible range of relevant biomarkers.

Methods:

In an investigator-initiated, open-labeled, crossover trial, we included HIV-infected males receiving either ABC or TDF and switched treatment to the alternate drug. At inclusion and after three months on the new regimen, we performed Multiplate® and thromboelastography (TEG®) and measured biomarkers of coagulation, inflammation, platelet reactivity, endothelial disruption and activation, and fibrinolysis, lipids, HIV RNA, CD4, CD8, and creatinine. Treatment effects were assessed by comparing intraindividual differences between the two treatment orders by the Wilcoxon Rank Sum test.

Results:

In total, 43 individuals completed the study. No intraindividual differences were observed for Multiplate® or TEG® when switching between regimens. We observed a significant treatment effect on coagulation factors II-VII-X (p<0.0001), sCD40L (a biomarker of platelet reactivity, p=0.04), thrombomodulin (biomarker of endothelial damage, p=0.04), lipids, and CD8 cell counts (p=0.04), with higher values during ABC treatment compared to TDF.

Conclusion:

Compared to TDF, ABC treatment affected several outcome measures in a pro-coagulant direction. Suggesting that the risk of MI associated with ABC may be caused by the sum of multiple, discrete disturbances in the hemostatic system and endothelium.

Study Registration:

The trial was registered at clinicaltrials.gov (NCT02093585).

Challenges in Platelet Functions in HIV/AIDS Management

The interest in platelet functions in HIV/AIDS is due to the high incidence of microvascular thrombosis in these individuals. A lot of laboratory data have been generated regarding platelet functions in this population. The tests demonstrate platelet hyperactivity but decreased aggregation, though results are inconsistent depending on the study design. Antiretroviral treatments currently in use display complex interactions. Many studies on platelet functions in these patients have been for research purposes, but none have found utility in guiding drug treatment of thrombosis.

Has modern human immunodeficiency virus therapy decreased complications following total knee arthroplasty?

BACKGROUND

Anti-retroviral therapy (ART) remains the cornerstone of decreasing morbidity and mortality in human immunodeficiency virus (HIV) patients. However, a large study comparing HIV patients taking ART prior to total knee arthroplasty (TKA) is lacking. We sought to examine: (1) readmissions; (2) post-operative complications; and (3) revisions in ART-treated or untreated HIV patients compared with a non-HIV population.

METHODS

We queried a national, all-payer database to identify TKA patients from 2010-2020 (n = 1,393,357). The presence or absence of ART was identified and matched with non-HIV patients based on age, sex, diabetes, obesity, and tobacco status resulting in 889 patients in each cohort. Readmissions, post-operative complications, and revisions were assessed.

RESULTS

Readmissions were higher among all HIV patients and even higher in those not taking ART, as compared to the matching cohort (4.8 versus 1.6%, p < 0.01). Prosthetic joint infections (PJIs) at 1-year were higher among HIV patients who were either taking ART (4.0%; OR, 1.41 [0.82-2.45]) or not taking ART (5.1%; OR, 2.44 [1.42-4.21]) as compared to non-HIV patients (2.1%, all p < 0.03). Revision rates at 1-year trended higher in HIV patients who were taking ART (2.6%; Odds Ratio (OR), 1.94 [0.96-3.93]) and who did not take ART (3.1%; OR, 2.38 [1.20-4.70]), compared to non-HIV patients (1.3%, all p < 0.09).

CONCLUSIONS

ART-treated HIV patients are associated with lower readmissions, post-operative complications, and revisions when compared to HIV patients not taking ART. The findings of this study underscore the utility of ART and patient optimization to reduce risk in HIV patients.

SARS-CoV-2 spike protein S1 induces fibrin(ogen) resistant to fibrinolysis: implications for microclot formation in COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2)-induced infection, the cause of coronavirus disease 2019 (COVID-19), is characterized by unprecedented clinical pathologies. One of the most important pathologies, is hypercoagulation and microclots in the lungs of patients. Here we study the effect of isolated SARS-CoV-2 spike protein S1 subunit as potential inflammagen sui generis. Using scanning electron and fluorescence microscopy as well as mass spectrometry, we investigate the potential of this inflammagen to interact with platelets and fibrin(ogen) directly to cause blood hypercoagulation. Using platelet-poor plasma (PPP), we show that spike protein may interfere with blood flow. Mass spectrometry also showed that when spike protein S1 is added to healthy PPP, it results in structural changes to β and γ fibrin(ogen), complement 3, and prothrombin. These proteins were substantially resistant to trypsinization, in the presence of spike protein S1. Here we suggest that, in part, the presence of spike protein in circulation may contribute to the hypercoagulation in COVID-19 positive patients and may cause substantial impairment of fibrinolysis. Such lytic impairment may result in the persistent large microclots we have noted here and previously in plasma samples of COVID-19 patients. This observation may have important clinical relevance in the treatment of hypercoagulability in COVID-19 patients.

Platelets in HIV: A Guardian of Host Defence or Transient Reservoir of the Virus?

The immune and inflammatory responses of platelets to human immunodeficiency virus 1 (HIV-1) and its envelope proteins are of great significance to both the treatment of the infection, and to the comorbidities related to systemic inflammation. Platelets can interact with the HIV-1 virus itself, or with viral membrane proteins, or with dysregulated inflammatory molecules in circulation, ensuing from HIV-1 infection. Platelets can facilitate the inhibition of HIV-1 infection via endogenously-produced inhibitors of HIV-1 replication, or the virus can temporarily hide from the immune system inside platelets, whereby platelets act as HIV-1 reservoirs. Platelets are therefore both guardians of the host defence system, and transient reservoirs of the virus. Such reservoirs may be of particular significance during combination antiretroviral therapy (cART) interruption, as it may drive viral persistence, and result in significant implications for treatment. Both HIV-1 envelope proteins and circulating inflammatory molecules can also initiate platelet complex formation with immune cells and erythrocytes. Complex formation cause platelet hypercoagulation and may lead to an increased thrombotic risk. Ultimately, HIV-1 infection can initiate platelet depletion and thrombocytopenia. Because of their relatively short lifespan, platelets are important signalling entities, and could be targeted more directly during HIV-1 infection and cART.