COVID-19 and venous thromboembolism: A narrative review

COVID-19 Coagulopathy

Coronavirus disease of 2019 (COVID-19) is the respiratory viral infection caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite being a primary respiratory illness, it is commonly complicated by systemic involvement of the vasculature leading to arterial and venous thrombosis. In this review, we will focus on the association between COVID-19 and thrombosis. We will highlight the pathophysiology of COVID-19 coagulopathy. The clinical manifestations of COVID-19 vasculopathy will be discussed with a focus on venous and arterial thromboembolic events. COVID-19 vasculopathy and disseminated intravascular coagulation (DIC) are distinguished within, as well as areas of controversy, such as "long COVID". Finally, the current professional guidelines on prevention and treatment of thrombosis associated with SARS-CoV-2 infection will be discussed.

The Top 100 Most-Cited Articles in Venous Disease and Management

BACKGROUND

Advancements in the management of venous disease have been documented in scientific literature. We performed a bibliometric analysis using citations as an indication of impact to analyze the most influential articles on venous disease and treatment.

METHODS

A retrospective search of the Web of Science database was conducted in May 2023. Key search terms were queried to generate relevant articles. Articles were ranked on total number of citations and average number of citations per year. Metrics analyzed included top journals, impact factor, journal discipline, institution and country of publication, author degree and gender, number of publications per year, level of evidence, and article topic area.

RESULTS

The top 100 articles on venous disease were published between 1994 and 2020, with a total of 102,856 citations, average 1,028 citations/article, and mean of 70 citations/year. The most popular article was "Incidence of thrombotic complications of in critically ill Intensive Care Unit patients with COVID-19" with 3,482 citations in total. The most popular journals were New England Journal of Medicine (22 articles), Lancet (14 articles), and CHEST (13 articles), pertaining to management of deep venous thrombosis (DVT). The Journal of Vascular surgery had 2 influential articles, focused on management of chronic venous disease. Many articles were published in the United States (52), Canada (38), and Netherlands (25). Prolific authors were predominantly male (96%) and 59% were MDs versus 29% combined MD/PhD and 12% PhDs. Popular venous articles included guidelines/standards for DVT management (12%), epidemiology of venous thromboembolism (12%), and anticoagulation for DVT (12%). Specific venous thromboembolism risk factors within popular literature included prothrombotic genes, malignancy, pregnancy, trauma, and COVID-19. Articles on surgical interventions included inferior vena cava filter placement, catheter-directed thrombolysis, and risks of femoral and subclavian vein catheterization. Venous stenting and mechanical thrombectomy were not within the top articles.

CONCLUSIONS

Top-cited articles on venous disease emphasized management of DVT, followed by chronic venous disease, through the collaboration of multiple medical and surgical specialties. The largest number of citations in recent DVT literature was driven by COVID-19 complications.

Simultaneous portal vein thrombosis and splenic vein thrombosis in a COVID-19 patient: A case report and review of literature

BACKGROUND

It is well-described that the coronavirus disease 2019 (COVID-19) infection is associated with an increased risk of thrombotic complications. While there have been many cases of pulmonary emboli and deep vein thrombosis in these patients, reports of COVID-19 associated portal vein thrombosis (PVT) have been uncommon. We present a unique case of concomitant PVT and splenic artery thrombosis in a COVID-19 patient.

CASE SUMMARY

A 77-year-old-male with no history of liver disease presented with three days of left-sided abdominal pain. One week earlier, the patient was diagnosed with mildly symptomatic COVID-19 and was treated with nirmatrelvir/ritonavir. Physical exam revealed mild right and left lower quadrant tenderness, but was otherwise unremarkable. Significant laboratory findings included white blood cell count 12.5 K/μL, total bilirubin 1.6 mg/dL, aminoaspartate transferase 40 U/L, and alanine aminotransferase 61 U/L. Computed tomography of the abdomen and pelvis revealed acute PVT with thrombus extending from the distal portion of the main portal vein into the right and left branches. Also noted was a thrombus within the distal portion of the splenic artery with resulting splenic infarct. Hypercoagulable workup including prothrombin gene analysis, factor V Leiden, cardiolipin antibody, and JAK2 mutation were all negative. Anticoagulation with enoxaparin was initiated, and the patient's pain improved. He was discharged on apixaban.

CONCLUSION

It is quite uncommon for PVT to present simultaneously with an arterial thrombotic occlusion, as in the case of our patient. Unusual thrombotic manifestations are classically linked to hypercoagulable states including malignancy and hereditary and autoimmune disorders. Viral infections such as Epstein-Barr virus, cytomegalovirus, viral hepatitis, and COVID-19 have all been found to increase the risk of splanchnic venous occlusions, including PVT. In our patient, prompt abdominal imaging led to early detection of thrombus, early treatment, and an excellent outcome. This case is unique in that it is the second known case within the literature of simultaneous PVT and splenic artery thrombosis in a COVID-19 patient.

Successfully conservative management of the uterus in acute pulmonary embolism during cesarean section for placenta previa: a case report from Tu Du Hospital, Vietnam and literature review

BACKGROUND

Cardiopulmonary collapse is a catastrophic event in cesarean section, which leads to adverse outcomes for both the mother and the fetus. Pulmonary embolism is one of the rare etiologies of this entity. We herein reported the successful management of acute embolism pulmonary associated with cesarean delivery on a healthy pregnant woman at our tertiary referral hospital.

CASE PRESENTATION

A full-term pregnant woman hospitalized for planned cesarean delivery due to placenta previa without cardiorespiratory diseases. She was scheduled uneventfully for a planned cesarean section. After placental delivery, the patient spontaneously fell into cardiopulmonary collapse and her vital signs deteriorated rapidly. The obstetricians promptly completed the cesarean section and performed all procedures to prevent the PPH and preserve the uterus. At the same time, the anesthesiologists continued to carry out advanced heart-lung resuscitation in order to control her vital signs. After surgery, the multidisciplinary team assessed the patient and found a thrombus in her pulmonary circulation. Therefore, the patient was managed with therapeutic anticoagulation. The patient recovered in good clinical condition and was discharged after 2 weeks without any complications.

CONCLUSIONS

The diagnosis of acute pulmonary embolism is extremely difficult due to uncommon occurrence, sudden onset, and non-specific presentation. Awareness of this life-threatening pathology during cesarean delivery should be raised. Interdisciplinary assessment must be essentially established in this life-threatening condition. After the whole conventional management, uterine conservation may be acceptable where applicable. Further data is required to encourage this finding.

Inflammation and Venous Thromboembolism in Hospitalized Patients with COVID-19

BACKGROUND

A link between inflammation and venous thromboembolism (VTE) in COVID-19 disease has been suggested pathophysiologically and clinically. The aim of this study was to investigate the association between inflammation and disease outcomes in adult hospitalized COVID-19 patients with VTE.

METHODS

This was a retrospective observational study, including quantitative and qualitative data collected from COVID-19 patients hospitalized at the Infectious Diseases Unit (IDU) of the University Hospital of Ioannina, from 1 March 2020 to 31 May 2022. Venous thromboembolism was defined as a diagnosis of pulmonary embolism (PE) and/or vascular tree-in-bud in the lungs. The burden of disease, assessed by computed tomography of the lungs (CTBoD), was quantified as the percentage (%) of the affected lung parenchyma. The study outcomes were defined as death, intubation, and length of hospital stay (LoS). A chi-squared test and univariate logistic regression analyses were performed in IBM SPSS 28.0.

RESULTS

After propensity score matching, the final study cohort included 532 patients. VTE was found in 11.2% of the total population. In patients with VTE, we found that lymphocytopenia and a high neutrophil/lymphocyte ratio were associated with an increased risk of intubation and death, respectively. Similarly, CTBoD > 50% was associated with a higher risk of intubation and death in this group of patients. The triglyceride-glucose (TyG) index was also linked to worse outcomes.

CONCLUSIONS

Inflammatory indices were associated with VTE. Lymphocytopenia and an increased neutrophil-to-lymphocyte ratio negatively impacted the disease's prognosis and outcomes. Whether these indices unfavorably affect outcomes in COVID-19-associated VTE must be further evaluated.

Effect of anti-SARS-CoV-2 BNT162b2 mRNA vaccination on thrombin generation in children with inflammatory bowel disease

Background

Inflammatory bowel disease (IBD) including Crohn's disease (CD) and ulcerative colitis (UC), are associated with higher thrombotic risk and enhanced thrombin generation (TG) in adults. Despite encouraging data reporting vaccine safety and low IBD flare rates in adults with IBD, vaccine hesitancy was demonstrated to be high in families of children with IBD. We aimed to find out whether TG is increased in children with IBD as compared to healthy controls and whether TG parameters show significant changes following SARS-CoV-2 mRNA vaccination.

Patients and methods

In this observational case-control study, 38 children with IBD (CD:18, UC: 20) aged 12-18 years and 62 healthy age-and sex-matched children were enrolled. Blood was collected before the first dose and 2-6 weeks after the second dose of BNT162b2 (Pfizer-BioNTech) mRNA vaccine dose. Blood cell counts, fibrinogen, inflammatory markers (hsCRP, ferritin), anti-SARS-CoV-2 antibody levels were investigated, TG assay was carried-out using platelet-poor plasma. Detailed clinical parameters including disease activity scores (PUCAI, PCDAI) were registered pre-and post- vaccination. A guided questionnaire was used to collect data on adverse reactions (AEs) post- vaccination.

Results

Baseline TG parameters did not differ between patients and controls. Endogenous thrombin potential showed a significant positive correlation with markers of inflammation and with PCDAI. Inflammatory parameters and TG did not increase in patients and controls post-vaccination. Vaccination significantly increased antibody levels in all three investigated groups, but post-vaccination anti-SARS-CoV-2 S IgG/IgM levels were below the 5th percentile value of healthy children in more than one third of patients. Those receiving TNFα inhibitor therapy presented significantly lower SARS-CoV-2 S IgG/IgM levels as compared to patients on other immunosuppressive regimens. Systemic AEs did not differ between patients and controls while lower rate of local symptoms was found post-vaccination in children with IBD. Only 2 IBD flares were detected 2-6 weeks after the second dose of vaccination.

Conclusion

Our study is the first to support the safety and efficacy of anti-SARS-CoV-2 BNT162b2 vaccination in children with IBD with detailed pre-and post-vaccination laboratory data including TG. Results of this study may further increase confidence and reduce vaccine hesitancy in caretakers of pediatric IBD patients.

COVID-19 Complications: Oxidative Stress, Inflammation, and Mitochondrial and Endothelial Dysfunction

SARS-CoV-2 infection, discovered and isolated in Wuhan City, Hubei Province, China, causes acute atypical respiratory symptoms and has led to profound changes in our lives. COVID-19 is characterized by a wide range of complications, which include pulmonary embolism, thromboembolism and arterial clot formation, arrhythmias, cardiomyopathy, multiorgan failure, and more. The disease has caused a worldwide pandemic, and despite various measures such as social distancing, various preventive strategies, and therapeutic approaches, and the creation of vaccines, the novel coronavirus infection (COVID-19) still hides many mysteries for the scientific community. Oxidative stress has been suggested to play an essential role in the pathogenesis of COVID-19, and determining free radical levels in patients with coronavirus infection may provide an insight into disease severity. The generation of abnormal levels of oxidants under a COVID-19-induced cytokine storm causes the irreversible oxidation of a wide range of macromolecules and subsequent damage to cells, tissues, and organs. Clinical studies have shown that oxidative stress initiates endothelial damage, which increases the risk of complications in COVID-19 and post-COVID-19 or long-COVID-19 cases. This review describes the role of oxidative stress and free radicals in the mediation of COVID-19-induced mitochondrial and endothelial dysfunction.

Rationale for combined therapies in severe-to-critical COVID-19 patients

An unprecedented global social and economic impact as well as a significant number of fatalities have been brought on by the coronavirus disease 2019 (COVID-19), produced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Acute SARS-CoV-2 infection can, in certain situations, cause immunological abnormalities, leading to an anomalous innate and adaptive immune response. While most patients only experience mild symptoms and recover without the need for mechanical ventilation, a substantial percentage of those who are affected develop severe respiratory illness, which can be fatal. The absence of effective therapies when disease progresses to a very severe condition coupled with the incomplete understanding of COVID-19's pathogenesis triggers the need to develop innovative therapeutic approaches for patients at high risk of mortality. As a result, we investigate the potential contribution of promising combinatorial cell therapy to prevent death in critical patients.

Biological mechanisms underpinning the development of long COVID

As COVID-19 evolves from a pandemic to an endemic disease, the already staggering number of people that have been or will be infected with SARS-CoV-2 is only destined to increase, and the majority of humanity will be infected. It is well understood that COVID-19, like many other viral infections, leaves a significant fraction of the infected with prolonged consequences. Continued high number of SARS-CoV-2 infections, viral evolution with escape from post-infection and vaccinal immunity, and reinfections heighten the potential impact of Long COVID. Hence, the impact of COVID-19 on human health will be seen for years to come until more effective vaccines and pharmaceutical treatments become available. To that effect, it is imperative that the mechanisms underlying the clinical manifestations of Long COVID be elucidated. In this article, we provide an in-depth analysis of the evidence on several potential mechanisms of Long COVID and discuss their relevance to its pathogenesis.

Development of a Decision Support Tool for Anticoagulation in Critically Ill Patients Admitted for SARS-CoV-2 Infection: The CALT Protocol

Severe COVID-19 infections are at high risk of causing thromboembolic events (TEEs). However, the usual exams may be unavailable or unreliable in predicting the risk of TEEs at admission or during hospitalization. We performed a retrospective analysis of two centers (n = 124 patients) including severe COVID-19 patients to determine the specific risk factors of TEEs in SARS-CoV-2 infection at admission and during stays at the intensive care unit (ICU). We used stepwise regression to create two composite scores in order to predict TEEs in the first 48 h (H0-H48) and during the first 15 days (D1-D15) in ICU. We then evaluated the performance of our scores in our cohort. During the period H0-H48, patients with a TEE diagnosis had higher D-Dimers and ferritin values at day 1 (D1) and day 3 (D3) and a greater drop in fibrinogen between D1 and D3 compared with patients without TEEs. Over the period D1-D15, patients with a diagnosis of a TEE showed a more marked drop in fibrinogen and had higher D-Dimers and lactate dehydrogenase (LDH) values at D1 and D3. Based on ROC analysis, the COVID-related acute lung and deep vein thrombosis (CALT) 1 score, calculated at D1, had a diagnostic performance for TEEs at H0-H48, estimated using an area under the curve (AUC) of 0.85 (CI95%: 0.76-0.93, p < 10^-3). The CALT 2 score, calculated at D3, predicted the occurrence of TEEs over the period D1-D15 with an estimated AUC of 0.85 (CI95%: 0.77-0.93, p < 10^-3). These two scores were used as the basis for the development of the CALT protocol, a tool to assist in the decision to use anticoagulation during severe SARS-CoV-2 infections. The CALT scores showed good performances in predicting the risk of TEEs in severe COVID-19 patients at admission and during ICU stays. They could, therefore, be used as a decision support protocol on whether or not to initiate therapeutic anticoagulation.

SARS-CoV-2 variant-related abnormalities detected by prenatal MRI: a prospective case-control study

Background

There are known complications for fetuses after infection with SARS-CoV-2 during pregnancy. However, previous studies of SARS-CoV-2 in pregnancy have largely been limited to histopathologic studies of placentas and prenatal studies on the effects of different SARS-CoV-2 variants are scarce to date. To examine the effects of SARS-CoV-2 variants on the placenta and fetus, we investigated fetal and extra-fetal structures using prenatal MRI.

Methods

For this prospective case-control study, two obstetric centers consecutively referred pregnant women for prenatal MRI after confirmed SARS-CoV-2 infection. Thirty-eight prenatal MRI examinations were included after confirmed infection with SARS-CoV-2 and matched 1:1 with 38 control cases with respect to sex, MRI field strength, and gestational age (average deviation 1.76 ± 1.65, median 1.5 days). Where available, the pathohistological examination and vaccination status of the placenta was included in the analysis. In prenatal MRI, the shape and thickness of the placenta, possible lobulation, and vascular lesions were quantified. Fetuses were scanned for organ or brain abnormalities.

Findings

Of the 38 included cases after SARS-CoV-2 infection, 20/38 (52.6%) were infected with pre-Omicron variants and 18/38 (47.4%) with Omicron. Prenatal MRIs were performed on an average of 83 days (±42.9, median 80) days after the first positive PCR test. Both pre-Omicron (P = .008) and Omicron (P = .016) groups showed abnormalities in form of a globular placenta compared to control cases. In addition, placentas in the pre-Omicron group were significantly thickened (6.35, 95% CI .02-12.65, P = .048), and showed significantly more frequent lobules (P = .046), and hemorrhages (P = .002). Fetal growth restriction (FGR) was observed in 25% (n = 5/20, P = .017) in the pre-Omicron group.

Interpretation

SARS-CoV-2 infections in pregnancy can lead to placental lesions based on vascular events, which can be well visualized on prenatal MRI. Pre-Omicron variants cause greater damage than Omicron sub-lineages in this regard.

Funding

Vienna Science and Technology Fund.

Perioperative Prevention of Venous Thromboembolism in Abdominal Surgery Patients Based on the Caprini or the Padua Risk Score-A Single Centre Prospective Observational Study

Surgical patients should receive perioperative thromboprophylaxis based on risk assessment, and the Caprini score is validated for this purpose. Whether the Padua score, originally devised for medical patients, can be useful in surgical patients remains to be fully clarified. This study aimed to evaluate perioperative thromboprophylaxis based on the Caprini or the Padua score in elective abdominal surgery. A total of 223 patients undergoing elective abdominal surgery for malignant or benign disease were prospectively evaluated. The patients were divided into two groups in which thromboprophylaxis was prescribed according to either the Caprini score (n = 122) or the Padua score (n = 101). Patients with high-risk scores in both groups received nadroparin. The alternate risk score in each group was calculated for evaluation purposes only. During a 3-month follow-up, we assessed patients for symptomatic venous thromboembolism (VTE), bleeding, or mortality. In the Caprini score group, 87 patients (71%) had a high risk for VTE (≥5 points), while 38 patients (38%) had a high risk for VTE (≥4 points) in the Padua score group; p < 0.00001. The overall correlation between the Caprini and Padua scores was moderate (r= 0.619), with 85 patients having high Caprini and discordant Padua scores. Ten patients died during follow-up (4.5%), and five developed non-fatal symptomatic VTE (2.2%). Among the five major bleeding incidents recorded (1.8%), two cases were possibly associated with pharmacological thromboprophylaxis. The incidence of adverse outcomes did not differ between the two groups. The odds ratio for adverse outcomes was significantly higher with a high Caprini or Padua risk score, malignant disease, age ≥65 years, and active smoking. We found no significant differences in adverse outcomes between abdominal surgical patients who received perioperative thromboprophylaxis based on either the Caprini or the Padua risk score. However, a discordant Padua score was noted in almost 40% of patients who had a high Caprini score, suggesting that the latter may be more sensitive than the Padua score in surgical patients.

COVID-19 in patients with B cell immune deficiency

This article aims to describe the clinical manifestations and management of COVID-19 in patients with primary and secondary B cell deficient states. We describe the epidemiologic and clinical features as well as unique management paradigm including isolation precautions with COVID-19. We then focus upon primary and secondary preventive approaches including vaccination and pre- as well as post-exposure prophylaxis. Further, we elaborate upon the important disease specific risk factors in these patients and the need to conduct prospective clinical trials to develop individualized management strategies in this population.

Anticoagulation in hospitalized patients with COVID-19

Coronavirus disease-19 (COVID-19) includes a thromboinflammatory syndrome that may manifest with microvascular and macrovascular thrombosis. Patients with COVID-19 have a higher incidence of venous thromboembolism than other hospitalized patients. Three randomized control trials suggesting benefit of therapeutic heparin in hospitalized noncritically ill patients with COVID-19 have led to conditional guideline recommendations for this treatment. By contrast, prophylactic-dose heparin is recommended for critically ill patients. Unprecedented collaboration and rapidly funded research have improved care of hospitalized patients with COVID-19.

The Incidence of Venous Thromboembolism in Critically Ill Patients with SARS-CoV-2 Infection Compared with Critically Ill Influenza and Community-Acquired Pneumonia Patients: A Retrospective Chart Review

The rate of venous thromboembolism in COVID-19 patients has been reported to be 30% (deep vein thrombosis 20% and pulmonary embolism 18%). This has been shown to be higher in COVID-19 patients admitted to the ICU. Prophylactic anticoagulation may be sufficient at ward level, but not in intensive care. A retrospective chart review was undertaken in a large university hospital. The review included 276 patients from COVID-19 Wave 1, COVID-19 Wave 2, influenza, and community-acquired pneumonia groups. The timeframe included patients admitted between 23 February 2014 and 12 May 2021. Clinical characteristics, outcomes, blood results, rates of venous thromboembolism, and anticoagulation status were recorded. The incidence of venous thromboembolism in COVID-19 Wave 1, COVID-19 Wave 2, influenza, and community-acquired pneumonia was 10.91%, 13.69%, 13.33%, and 6.81%, respectively (p = 0.481). The incidence of pulmonary embolism was 7.27%, 10.95%, 3.33%, and 5.68%, respectively (p = 0.350). The incidence of deep vein thrombosis was 5.45%, 5.48%, 10.00%, and 1.14%, respectively (p = 0.117). Although most patients were prophylactically anticoagulated, venous thromboembolism still occurred. Venous thromboembolism remains an important differential to consider in critically ill COVID-19 patients. The current literature does not advise therapeutic anticoagulation for thromboprophylaxis in the ICU.

Venous Thromboembolism and COVID-19-an Epidemiological Perspective

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was declared as pandemic by World Health Organization (WHO) in March 2020. The outbreak has caused 5,232,562 deaths worldwide until December 3rd, 2021. Though primarily affecting the respiratory system, involvement of other organ systems have been reported in severe disease. Venous thromboembolism (VTE) has been recognized as an important complication. Previous studies have reported the prevalence of VTE in intensive care unit (ICU) patients between 7 and 85% and in non-ICU patients between 0 and 19%. COVID-19 patients that are at high risk for VTE are also at increased risk for bleeding. In such cases, anticoagulation may potentially be harmful. Thereby, it is important to understand the risk factors for VTE predisposition in the COVID-19 patients, timing of VTE, and the rate of occurrence of VTE in hospitalized patients post-discharge. Comparison of the rate of occurrence of VTE in COVID-19 patients with the non-COVID-19 patients with similar disease severity is required to truly interpret the reportedly high rates of VTE in COVID-19 patients. Several pathophysiological mechanisms have been reported for the development of VTE in COVID-19. Autopsy-based studies have contributed to the existing knowledge. d-dimer, presently, seems to be the most suitable investigation for risk-identification of VTE supported by Doppler studies and overall clinical context. Further, prospective studies and clinical trials are essentially required to fill the gaps in evidence for occurrence, risk prediction and management of VTE in COVID-19 patients.