Pulmonary Embolism in Patients with COVID-19

Infection with the novel severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) and the resulting syndrome, COVID-19, have been associated with inflammation and a prothrombotic state, with increases in fibrin, fibrinogen, fibrin degradation products and D-dimers. In some studies, elevations in these markers have been associated with worse clinical outcomes. Several studies have demonstrated a high prevalence of venous thromboembolism (VTE), and pulmonary embolism (PE), particularly in patients admitted to the intensive care unit (ICU), even in those receiving prophylactic anticoagulation. The high rate of thrombosis in COVID-19 is driven by at least two interrelated processes: a hypercoagulable state responsible for large-vessel thrombosis and thromboembolism and direct vascular and endothelial injury responsible for in situ microvascular thrombosis. The presence of PE and pulmonary thrombosis may explain why hypoxemia is out of proportion to impairment in lung compliance in some patients with COVID-19 pneumonia. Diagnosing PE in patients with COVID-19 pneumonia may be challenging, because the two pathologies share many signs and symptoms. It has been demonstrated that the administration of prophylactic anticoagulation within 24 h of admission in patients with COVID-19 was associated with decreased mortality when compared with no prophylactic anticoagulation. Given the antithrombotic, anti-inflammatory and possibly antiviral properties of heparins, it has been hypothesized that anticoagulation with heparin administered at doses higher than conventionally used for venous thromboprophylaxis may improve outcomes. In non-critically ill patients hospitalized with COVID-19, therapeutic-dose anticoagulants with heparin (most commonly, low-molecular-weight heparin) increased the probability of survival until hospital discharge with a reduced need for ICU-level organ support at 21 days as compared with usual-care thromboprophylaxis. In Critically ill patients with confirmed COVID-19, therapeutic-dose anticoagulation did not increase the probability of survival to hospital discharge or the number of days free of cardiovascular o respiratory organ support and had a 95% probability of being inferior to usual-care pharmacologic thromboprophylaxis. Currently, randomized trials evaluating the use of tissue plasminogen activator and Tenecteplase in patients with COVID-19 ARDS are underway.

COVID-19 and thrombosis: searching for evidence

Early in the pandemic, COVID-19-related increases in rates of venous and arterial thromboembolism were seen. Many observational studies suggested a benefit of prophylactic anticoagulation for hospitalized patients using various dosing strategies. Randomized trials were initiated to compare the efficacy of these different options in acutely ill and critically ill inpatients as the concept of immune-mediated inflammatory microthrombosis emerged. We present a case-based review of how we approach thromboembolic prophylaxis in COVID-19 and briefly discuss the epidemiology, the pathophysiology, and the rare occurrence of vaccine-induced thrombotic thrombocytopenia.

123 Prophylactic anticoagulation and aspirin therapy for hospitalized patients with COVID-19: a propensity score-matched analysis of the hope-COVID-19 registry

Aims No standard therapy is currently recommended for moderately ill Corona-virus-19 disease (COVID-19) patients. Potential benefit in terms of survival for anticoagulation were found only in this subset of patients. Aim of this study was to evaluate safety and efficacy of add-on antiplatelet therapy with aspirin over prophylactic anticoagulation (PAC) in COVID-19 hospitalized patients and its impact on survival. Methods and results 7824 consecutive patients with COVID-19 were enrolled in a multicentre-international prospective registry (HOPE-COVID-19). Clinical data and in-hospital complications, including mortality, were recorded. Study population included only patients treated with aspirin and/or PAC. A comparison of clinical outcomes between add-on antiplatelet therapy and PAC and patients treated with PAC only was performed using an adjusted analysis with propensity score (PS) matching. Of 7824 patients, 360 (4.6%) received PAC and aspirin and 2949 (37.6%) PAC only. Propensity-score matching yielded 298 patients from each group. Mean age was 73 ± 11 years, 67% were male, prevalence of hypertension and diabetes was 79% and 33%, respectively, and 7.5 % underwent invasive ventilation. In the propensity score-matched population, cumulative incidence curves of in-hospital mortality were lower in patients treated with PAC and Aspirin vs. PAC only (15% vs. 21%, Log Rank P = 0.01). At multivariable analysis in propensity matched population of COVID-19 patients, including age, sex, hypertension, diabetes, kidney failure and invasive ventilation, aspirin treatment was associated with lower risk of in-hospital mortality (HR: 0.62, CI: 95% 0.42–0.92, P = 0.018). Conclusions Add-on anti-platelet therapy with aspirin over PAC in COVID-19 hospitalized patients was associated with lower mortality risk in a propensity score matched population.

Novel Coronavirus Infection (COVID-19) Related Thrombotic and Bleeding Complications in Critically Ill Patients: Experience from an Academic Medical Center

Introduction: Thrombosis and bleeding are recognized complications of the novel coronavirus infection (COVID-19), with a higher incidence described particularly in the critically ill. Methods: A retrospective review of COVID-19 patients admitted to our intensive care units (ICU) between 1 January 2020 and 31 December 2020 was performed. Primary outcomes included clinically significant thrombotic and bleeding events (according to the ISTH definition) in the ICU. Secondary outcomes included mortality vis-a-vis the type of anticoagulation. Results: The cohort included 144 consecutive COVID-19 patients with a median age of 64 years (IQR 54.5–75). The majority were male (85 (59.0%)) and Caucasian (90 (62.5%)) with a median BMI of 30.5 kg/m2 (IQR 25.7–36.1). The median APACHE score at admission to the ICU was 12.5 (IQR 9.5–22). The coagulation parameters at admission were a d-dimer level of 109.2 mg/mL, a platelet count of 217.5 k/mcl, and an INR of 1.4. The anticoagulation strategy at admission included prophylactic anticoagulation for 97 (67.4%) patients and therapeutic anticoagulation for 35 (24.3%) patients, while 12 (8.3%) patients received no anticoagulation. A total of 29 patients (20.1%) suffered from thrombotic or major bleeding complications. These included 17 thrombus events (11.8%)—8 while on prophylactic anticoagulation (7 regular dose and 1 intermediate dose) and 9 while on therapeutic anticoagulation (p-value = 0.02)—and 19 major bleeding events (13.2%) (4 on no anticoagulation, 7 on prophylactic (6 regular dose and 1 intermediate dose), and 8 on therapeutic anticoagulation (p-value = 0.02)). A higher thrombosis risk among patients who received remdesivir (18.8% vs. 5.3% (p-value = 0.01)) and convalescent serum (17.3% vs. 5.8% (p-value = 0.03%)) was noted, but no association with baseline characteristics (age, sex, race, comorbidity), coagulation parameters, or treatments (steroids, mechanical ventilation) could be identified. There were 10 pulmonary embolism cases (6.9%). A total of 99 (68.8%) patients were intubated, and 66 patients (45.8%) died. Mortality was higher, but not statistically significant, in patients with thrombotic or bleeding complications—58.6% vs. 42.6% (p-value = 0.12)—and higher in the bleeding (21.2%) vs. thrombus group (12.1%), p-value = 0.06. It did not significantly differ according to the type of anticoagulation used or the coagulation parameters. Conclusions: This study describes a high incidence of thrombotic and bleeding complications among critically ill COVID-19 patients. The findings of thrombotic events in patients on anticoagulation and major bleeding events in patients on no or prophylactic anticoagulation pose a challenging clinical dilemma in the issue of anticoagulation for COVID-19 patients. The questions raised by this study and previous literature on this subject demonstrate that the role of anticoagulation in COVID-19 patients is worthy of further investigation.

Thrombosis and Bleeding After Implementation of an Intermediate-Dose Prophylactic Anticoagulation Protocol in ICU Patients With COVID-19: A Multicenter Screening Study

Thrombosis and bleeding after implementation of an intermediate-dose prophylactic anticoagulation protocol in intensive care unit (ICU) patients with coronavirus disease 2019 (COVID-19): a multicenter screening study Background: Venous thromboembolism (VTE) is common among critically ill patients with COVID-19. Information regarding VTE prevalence and bleeding complications after implementation of intermediate-dose prophylactic anticoagulation in such patients is, however, limited. Methods: We performed a prospective, observational study in 6 ICUs in 2 university-affiliated teaching hospitals in Sweden. After implementation of an intermediate-dose prophylactic anticoagulation protocol, we performed ultrasound screening for proximal lower-extremity deep vein thrombosis (DVT) and collected routine computed tomography pulmonary angiography exam results. Results: A total of 100 COVID-19 patients were included from June 21, 2020, through February 18, 2021. During a median follow-up of 120 (IQR, 89-134) days, we found VTE in 37 patients with the majority (78.4%) being diagnosed after ICU arrival. Overall, 20 patients had proximal lower-extremity DVT with 95% being detected on ultrasound screening; 22 patients had pulmonary vascular thrombosis; and 4 patients had venous thrombosis at other sites. A total of 6 patients had both proximal lower-extremity DVT and pulmonary vascular thrombosis. On univariate logistic regression analysis of 14 baseline characteristics, only pre-existing heart failure was associated with VTE (OR 4.67, 95% CI 1.13-19.34). Major and non-major bleeding occurred in 10 and 18 patients, respectively. Conclusions: In our cohort of ICU patients with COVID-19, we observed a high prevalence of VTE and bleeding complications after implementation of intermediate-dose anticoagulation. In approximately half of patients, VTE was identified on screening ultrasound.

Intermediate-to-therapeutic versus prophylactic anticoagulation for coagulopathy in hospitalized COVID-19 patients: a systemic review and meta-analysis

Background Anticoagulation in hospitalized COVID-19 patients has been associated with survival benefit; however, the optimal anticoagulant strategy has not yet been defined. The objective of this meta-analysis was to investigate the effect of intermediate-to-therapeutic versus prophylactic anticoagulation for thromboprophylaxis on the primary outcome of in-hospital mortality and other patient-centered secondary outcomes in COVID-19 patients. Methods MEDLINE, EMBASE, and Cochrane databases were searched from inception to August 10th 2021. Cohort studies and randomized clinical trials that assessed the efficacy and safety of intermediate-to-therapeutic versus prophylactic anticoagulation in hospitalized COVID-19 patients were included. Baseline characteristics and relevant data of each study were extracted in a pre-designed standardized data-collection form. The primary outcome was all-cause in-hospital mortality and the secondary outcomes were incidence of thrombotic events and incidence of any bleeding and major bleeding. Pooled analysis with random effects models yielded relative risk with 95 % CIs. Results This meta-analysis included 42 studies with 28,055 in-hospital COVID-19 patients totally. Our pooled analysis demonstrated that intermediate-to-therapeutic anticoagulation was not associated with lower in-hospital mortality (RR=1.12, 95 %CI 0.99-1.25, p=0.06, I2=77 %) and lower incidence of thrombotic events (RR=1.30, 95 %CI 0.79-2.15, p=0.30, I2=88 %), but increased the risk of any bleeding events (RR=2.16, 95 %CI 1.79-2.60, p<0.01, I2=31 %) and major bleeding events significantly (RR=2.10, 95 %CI 1.77-2.51, p<0.01, I2=11 %) versus prophylactic anticoagulation. Moreover, intermediate-to-therapeutic anticoagulation decreased the incidence of thrombotic events (RR=0.71, 95 %CI 0.56-0.89, p=0.003, I2=0 %) among critically ill COVID-19 patients admitted to intensive care units (ICU), with increased bleeding risk (RR=1.66, 95 %CI 1.37-2.00, p<0.01, I2=0 %) and unchanged in-hospital mortality (RR=0.94, 95 %CI 0.79-1.10, p=0.42, I2=30 %) in such patients. The Grading of Recommendation, Assessment, Development, and Evaluation certainty of evidence ranged from very low to moderate. Conclusions We recommend the use of prophylactic anticoagulation against intermediate-to-therapeutic anticoagulation among unselected hospitalized COVID-19 patients considering insignificant survival benefits but higher risk of bleeding in the escalated thromboprophylaxis strategy. For critically ill COVID-19 patients, the benefits of intermediate-to-therapeutic anticoagulation in reducing thrombotic events should be weighed cautiously because of its association with higher risk of bleeding. Trial registration The protocol was registered at PROSPERO on August 17th 2021 (CRD42021273780). Graphical abstract