Comparison of anticoagulation quality between acenocoumarol and warfarin in patients with mechanical prosthetic heart valves: Insights from the nationwide PLECTRUM study

Vitamin K antagonists are indicated for the thromboprophylaxis in patients with mechanical prosthetic heart valves (MPHV). However, it is unclear whether some differences between acenocoumarol and warfarin in terms of anticoagulation quality do exist. We included 2111 MPHV patients included in the nationwide PLECTRUM registry. We evaluated anticoagulation quality by the time in therapeutic range (TiTR). Factors associated with acenocoumarol use and with low TiTR were investigated by multivariable logistic regression analysis. Mean age was 56.8 ± 12.3 years; 44.6% of patients were women and 395 patients were on acenocoumarol. A multivariable logistic regression analysis showed that patients on acenocoumarol had more comorbidities (i.e., ≥3, odds ratio (OR) 1.443, 95% confidence interval (CI) 1.081-1.927, p = 0.013). The mean TiTR was lower in the acenocoumarol than in the warfarin group (56.1 ± 19.2% vs. 61.6 ± 19.4%, p < 0.001). A higher prevalence of TiTR (<60%, <65%, or <70%) was found in acenocoumarol users than in warfarin ones (p < 0.001 for all comparisons). Acenocoumarol use was associated with low TiTR regardless of the cutoff used at multivariable analysis. A lower TiTR on acenocoumarol was found in all subgroups of patients analyzed according to sex, hypertension, diabetes, age, valve site, atrial fibrillation, and INR range. In conclusion, anticoagulation quality was consistently lower in MPHV patients on acenocoumarol compared to those on warfarin

High pressure liquid chromatography and electrospray ionization mass spectrometry are advantageously integrated into a two-levels approach to detection and identification of haemoglobin variants

Detecting and correctly identifying haemoglobin (Hb) variants is typically achieved by a two-levels laboratory approach. We report our experience in dealing with 91 Hb variants, including a number of frequent and a few rare variants. Screening included akaline agarose gel electrophoresis (AGE), ion-exchange automated high-performance liquid chromatography (HPLC) and a test for deoxyhaemoglobin solubility. Identification was based on electrospray ionization-mass spectrometry (ESI-MS). Our results confirmed the advantages of HPLC over AGE for screening, because of the occurrence of some electrophoretically 'silent' variants. ESI-MS permitted the definitive identification of 90 of the 91 variants included in the study, in some cases (e.g. HbS) through the application of a simple protocol (direct injection of the sample), in other cases requiring the application of more demanding procedures (purification of the variant chain and peptide analysis after enzymatic or chemical cleavage). In an additional case (Hb J-Oxford), ESI-MS assay did not lead to definitive identification, but gave indications for designing the appropriate primers to focus DNA sequence analysis on the specific region of the gene. Deoxyhaemoglobin solubility test was positive only in the presence of HbS. We conclude that HPLC and ESI-MS are advantageously integrated into a two-level analytical system for the detection and confirmation of variant Hbs. (copyright) 2005 Blackwell Publishing Ltd

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