Anemone study: prevalence of risk factors for superficial vein thrombosis in a large Italian population of blood donors.

Knowledge of the distribution of risk factors for superficial thrombosis (SVT) in low-risk population is fundamental to improve the prevention of the disease in each individual and high-risk settings of patients. Exact frequency data for the low-risk population are scarce, but could be useful for optimal use of prophylactic strategies against venous thrombosis. Blood donors represent a low-risk population, because are healthier than the general population. The objective of this study was to assess the prevalence of vein thrombosis, particularly SVT, and associated risk factors in a low-risk population such as blood donors. In this multicentre cross-sectional study, donors from six Italian blood banks responded to a self-administered questionnaire. The enrolment lasted from 1st June 2017 to 30th July 2018. History of vein thrombosis was referred by 89 (0.76%) individuals, (49 men) with an age-dependent effect. The prevalence reached 2.9% in women and 0.8% in men aged ≥ 49 years, with a significant difference only for women. After controlling for potential confounders, a significant and independent association was found between a history of vein thrombosis and age (OR: 1.03, 95%CI 1.01-1.05), varicose veins (OR: 15.8, 95%CI 7.7-32.6), plaster cast/bed rest (OR: 2.3, 95% CI 1.0-5.3) and transfusion (OR: 5.1, 95% CI 1.3-19.5). This study shows that low-risk individuals share the same risk factors for SVT as patients in secondary care. It also suggests that transfusion confers an increased risk of SVT in healthy population.

Mechanical prosthetic heart valves: Quality of anticoagulation and thromboembolic risk. The observational multicenter PLECTRUM study.

BACKGROUND: Patients with a mechanical prosthetic heart valve implantation need to be treated with a vitamin K antagonist (VKA) due to a substantially high risk of thromboembolism. In this study we report data on patients with mechanical heart valves (MV), with the aim of evaluating the thromboembolic risk in relation to the type and site of implantation, quality of anticoagulation and risk factors associated with thromboembolism. METHODS: Observational retrospective multicenter study among Centers affiliated to the Italian Federation of Anticoagulation Clinics (FCSA) on patients with MV implanted after 1990 and followed for the management of anticoagulation. RESULTS: We analyzed 2357 patients with mechanical heart valves (55.2% males), followed for 24,081 years. During the follow-up, 164 thromboembolic events (0.67/100 pt-yrs) and 243 major bleedings (1.0/100 pt-yrs) occurred. The median Time in Therapeutic Range (TTR), calculated in all intended INR classes, was 60% (IQR 47-74%). The rates of thrombotic events were significantly higher in patients intended to stay at therapeutic ranges >INR 2.0-3.0. The presence of atrial fibrillation, history of thromboembolism and of mitral prosthesis were independently associated with thromboembolism. However, a bad quality of anticoagulation (TTR <47%, 25°percentile of our population) was not correlated with thromboembolism. CONCLUSIONS: A low rate of bleeding and thromboembolic events in patients with mechanical heart valves were found, despite the sub-optimal anticoagulation control. The thromboembolic risk was not associated with the low TTR.