Coagulation factors XI and XII as possible targets for anticoagulant therapy.

In this review, we give an overview over observational and experimental studies supporting factors XI and XII as targets for anticoagulant therapy. The majority of observational studies on FXI report low concentrations of FXI to be protective against ischemic stroke and venous thrombosis. There is also extensive evidence from experimental and animal studies supporting FXI inhibition as a target for anticoagulant therapy, alone or in combination with other antithrombotic treatments. Four Phase 2 clinical trials on patients undergoing total knee arthroplasty showed non-inferiority or superiority of FXI inhibition compared to enoxaparin for the primary outcome, which was incidence of venous thromboembolism. One Phase 2 trial reported that FXI inhibition is associated with fewer bleeding events than apixaban. The results from observational studies on FXII are more conflicting. Some show that low FXII concentrations confer protection against thrombosis, while others have found it to be deleterious. Results from experimental studies are inconclusive, but suggest that FXII inhibition might be useful in preventing thrombosis caused by foreign objects like catheters or mechanical heart valves. One Phase 2 study not conducted on thrombosis has reported FXII inhibition as safe. In conclusion, FXI seems to be a promising target for antithrombotic therapy, both alone and in combination with existing therapies, while the potential of targeting FXII is still unclear.

Cardiac Dysfunction and Arrhythmias 3 Months After Hospitalization for COVID-19.

Background The extent of cardiac dysfunction post-COVID-19 varies, and there is a lack of data on arrhythmic burden. Methods and Results This was a combined multicenter prospective cohort study and cross-sectional case-control study. Cardiac function assessed by echocardiography in patients with COVID-19 3 to 4 months after hospital discharge was compared with matched controls. The 24-hour ECGs were recorded in patients with COVID-19. A total of 204 patients with COVID-19 consented to participate (mean age, 58.5 years; 44% women), and 204 controls were included (mean age, 58.4 years; 44% women). Patients with COVID-19 had worse right ventricle free wall longitudinal strain (adjusted estimated mean difference, 1.5 percentage points; 95% CI, -2.6 to -0.5; P=0.005) and lower tricuspid annular plane systolic excursion (-0.10 cm; 95% CI, -0.14 to -0.05; P<0.001) and cardiac index (-0.26 L/min per m2; 95% CI, -0.40 to -0.12; P<0.001), but slightly better left ventricle global strain (-0.8 percentage points; 95% CI, 0.2-1.3; P=0.008) compared with controls. Reduced diastolic function was twice as common compared with controls (60 [30%] versus 29 [15%], respectively; odds ratio, 2.4; P=0.001). Having dyspnea or fatigue were not associated with cardiac function. Right ventricle free wall longitudinal strain was worse after intensive care treatment. Arrhythmias were found in 27% of the patients, mainly premature ventricular contractions and nonsustained ventricular tachycardia (18% and 5%, respectively). Conclusions At 3 months after hospital discharge with COVID-19, right ventricular function was mildly impaired, and diastolic dysfunction was twice as common compared with controls. There was little evidence for an association between cardiac function and intensive care treatment, dyspnea, or fatigue. Ventricular arrhythmias were common, but the clinical importance is unknown. Registration URL: http://clinicaltrials.gov. Unique Identifier: NCT04535154.