Ashkan Labaf

Thromboembolism, major bleeding and mortality in patients with mechanical heart valves- a population-based cohort study.

INTRODUCTION Low incidences of thromboembolism (TE) and bleeding in patients with mechanical heart valves (MHV) have previously been reported. This study assesses the incidence of and clinical risk factors predicting TE, major bleeding and mortality in a clinical setting. METHODS AND RESULTS All 546 patients undergoing anticoagulation treatment due to MHV replacement at hospitals in Malmö and Sundsvall in Sweden were monitored during 2008-2011 and the incidence of TE, major bleeding and mortality was prospectively followed. There were 398, 122 and 26 patients in the aortic group (AVR), mitral (MVR) group and the combined aortic/mitral valve group respectively. The incidence of TE was 1.8 and 2.2 per 100 patient-years in the AVR group MVR group respectively. The corresponding incidences of bleeding were 4.4 and 4.6, respectively. Independent predictor of thromboembolism was vascular disease (Odds ratio {OR}: 4.2; 95% CI: 1.0-17.4). Predictor of bleeding was previous bleeding (OR: 2.7; 95% CI: 1.4-5.3). Independent predictors of mortality was age (Hazard ratio {HR}: 1.03; 95% CI: 1.00-1.05), hypertension (HR: 2.4; 95% CI: 1.3-4.5), diabetes (HR: 2.4; 95% CI: 1.3-4.3) and alcohol overconsumption (HR: 5.2; 95% CI: 1.7-15.9). Standardized mortality/morbidity ratio for mortality and AMI was 0.99 (95% CI: 0.8-1.2) and 0.87 (95% CI: 0.5-1.2) respectively. CONCLUSION The incidence of TE and major bleeding in this unselected clinical population exceeds that of previously reported retrospective and randomized trials. Despite this, mortality is equal to that of the general population.

Mechanical heart valve prosthesis and warfarin – Treatment quality and prognosis

INTRODUCTION Every year about 2500 patients in Sweden undergo surgery due to heart valve disease. A mechanical heart valve prosthesis causes risk of thromboembolic stroke or thrombus formation in the valve while anticoagulant treatment increases the risk of bleeding. Treatment quality with warfarin is crucial for patients with mechanical valve prostheses. It has previously been shown that poorly controlled warfarin treatment increases mortality in this patient group. TTR (Time in Therapeutic Range) on warfarin has been shown to affect the risk of complications in atrial fibrillation, but has not been studied in patients with mechanical heart valves. Our aim is to evaluate the impact of TTR on the risk of complications in this patient group. MATERIALS AND METHODS A non-randomized, prospective study of 534 adults with mechanical heart valve prostheses from Malmö and Sundsvall registered in the Swedish National Quality Registry Auricula between 01.01.2008 and 31.12.2011. Quartiles regarding individual TTR levels were compared regarding risk of complications. RESULTS The risk of complications was significantly higher at lower TTR levels for all complications (p=0.005), bleeding (p=0.01) and death (p=0.018) but not for thromboembolism. In multivariate analysis the risk was significantly increased at lower TTR levels for bleeding and all complications but not for death or thromboembolism. CONCLUSION Patients with a lower warfarin treatment quality measured by TTR have a higher risk of complications such as severe bleeding or death. A TTR of 83% or higher at the individual level should be obtained for best outcome.

Incidence and risk factors for thromboembolism and major bleeding in patients with mechanical valve prosthesis: A nationwide population-based study.

BACKGROUND Risk factors of stroke/thromboembolism (TE) and major bleeding, and incidence of these events in specific age categories in warfarin-treated patients with mechanical heart valves (MHV) are uncertain. Our objective was to calculate event rates in specific age categories and identify risk factors for adverse events. METHODS AND RESULTS We identified 4,810 treatment periods with MHV between January 2006 and December 2011 in the Auricula and Swedish Web system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies registries. There were 3,751 treatment periods with aortic valve replacements (AVR) and 866 with mitral valve replacements (MVR). Median follow-up time was 4.5 years (IQR, 1.5-6.0). Time in therapeutic range with warfarin for patients with AVR was 74.2% for international normalized ratio of 2.0 to 3.0, with 72% of the patients having this target range. Rate of stroke/TE for AVR and MVR was 1.3 and 1.6 per 100 patient years, respectively (P=.20). The rate of first major bleeding was 2.6 and 3.9 per 100 patient years with AVR and MVR, respectively (P<.001). By multivariate analysis for AVR, age (hazard ratio [HR], 1.02; 95% confidence interval [CI], 1.01-1.03 per year) and previous stroke (HR, 2.4; 95% CI, 1.7-3.5) emerged as independent risk factors for stroke/TE. Heart failure (HR, 0.9; 95% CI, 0.6-1.4) and atrial fibrillation (HR, 1.0; 95% CI, 0.7-1.4) were not associated to stroke/TE. For major bleeding events, age (HR, 1.02; 95% CI, 1.01-1.03 per year) and previous major bleeding (HR, 2.5; 95% CI, 1.9-3.3) emerged as independent risk factors for AVR. CONCLUSIONS In a nationwide cohort study with MHV and high time in therapeutic range, heart failure and atrial fibrillation did not appear as risk factors of stroke/TE.

Glomerular filtration rate and association to stroke, major bleeding, and death in patients with mechanical heart valve prosthesis

AIMS The impact of estimated glomerular filtration rate (eGFR) on adverse events in patients with mechanical heart valves (MHVs) is unknown. We analyzed the independent association of eGFR and thromboembolism (TE), major bleeding, and mortality in patients with MHV in an observational cohort study. METHODS AND RESULTS All patients (n = 520) with MHV replacement on anticoagulation treatment were followed up prospectively regarding TE, major bleeding, and death at 2 anticoagulation centers during 2008 to 2011. The mean age was 69 years, 72% with aortic valve replacement, and time in therapeutic range 2.0 to 4.0 was 91%. The incidence of the combined end point of major bleeding, TE, and death increased sharply with each decreasing eGFR stratum: 5.5, 8.4, 16, and 32 per 100 patient-years for eGFR >60, 45 to 60, 30 to 45, and <30 mL/min per 1.73 m(2), respectively. After multivariate adjustment for comorbidities, every unit decrease in eGFR increased the risk of major bleeding by 2%, death by 3%, and the combined end point by 1%. There was no association between eGFR and TE. There was an increased proportion of international normalized ratio >3.0 and >4.0 and decreasing time in therapeutic range for each decreasing eGFR stratum (P < .001 for trend). The hazard ratios of the combined end point for eGFR <30, 30 to 45, and 45 to 60 mL/min per 1.73 m(2) were 3.2 (95% CI 1.8-5.6), 1.5 (95% CI 0.9-2.5), and 0.9 (95% CI 0.6-1.5), respectively, compared to eGFR >60 mL/min per 1.73 m(2). CONCLUSION In patients with MHV on anticoagulation, eGFR is an independent predictor of major bleeding and death and not TE.

Current evidence of oral anticoagulant reversal: A systematic review

INTRODUCTION Approximately 4-6% of patients treated with oral anticoagulants (OAC) will suffer from major hemorrhage or be in need of urgent surgery necessitating anticoagulant reversal therapy. Several new oral anticoagulants and reversal agents have been introduced that make it difficult for physicians to stay updated on the current evidence of reversal management. This study aims to review the recent literature on oral anticoagulation reversal therapy and to present the current evidence in an easily approachable manner. MATERIALS AND METHODS A systematic literature search was conducted using PubMed and EMBASE to identify the latest publications on both vitamin K antagonist (VKA) and direct oral anticoagulant (DOAC) reversal strategies. All studies on humans who received any acute reversal management of VKA treatment were included, except case studies. Since only two studies on acute reversal of DOAC treatment have been published, clinical trials on healthy volunteers were also included. RESULTS Twenty-one studies with a total of 4783 VKA treated patients, and 12 studies with a total of 529 DOAC treated patients were included. Elevated INR values due to VKA treatment could be reversed (INR≤1.5) in 63.1% (95% CI: 61.0-65.2) of study subjects after treatment with 4F-PCC, as compared with 12.2% (95% CI: 8.2-16.2) after treatment with fresh frozen plasma (FFP), (p<0.001). Thromboembolism occurred in 1.6% (95% CI: 1.2-2.1) of VKA-patients treated with 4F-PCC, and in 4.5% (95% CI: 2.3-6.7) of FFP-treated patients. To date, reversal of laboratory parameters has been demonstrated for two reversal agents specific to DOACs: idarucizumab for dabigatran reversal and andexanet-alfa for factor Xa-inhibitor reversal. CONCLUSIONS This review supports the use of PCC for VKA reversal, specifically for 4F-PCC over FFP for laboratory reversal. There are no studies on clinical efficacy of non-specific agents for DOAC reversal and the evidence for laboratory reversal is not consistent.

INR variability and outcomes in patients with mechanical heart valve prosthesis

BACKGROUND The quality of treatment with warfarin is mainly assessed by the time in therapeutic range (TTR) in patients with mechanical heart valve prosthesis (MHV). Our aim was to evaluate if International Normalized Ratio (INR) variability predicted a combined endpoint of thromboembolism, major bleeding and death better than TTR. METHODS AND RESULTS We included 394 patients at one center with MHV during 2008-2011 with adverse events and death followed prospectively. TTR 2.0-4.0 and log-transformed INR variability was calculated for all patients. In order to make comparisons between the measures, the gradient of the risk per one standard deviation (SD) was assessed. INR variability performed equal as TTR 2.0-4.0 per one SD unit adjusted for covariates, hazard ratio (HR) 1.30 (95% CI 1.1-1.5) and 0.71 (95% CI 0.6-0.8) respectively for the combined endpoint, and performed better for mortality HR 1.47 (95% CI 1.1-1.9) and 0.70 (95% CI 0.6-0.8). INR variability was categorized into high and low group and TTR into tertiles. High variability within the low and high TTR, had a HR 2.0 (95% CI 1.7-3.6) and 2.2 (95% CI 1.1-4.1) respectively, of the combined endpoint compared to the low variability/high TTR group. INR values <2.0 greatly increased the rate of thromboembolism whereas the rate of major bleeding increased moderately between INR 3.0 and 4.0 and increased substantially after INR >4.0. CONCLUSION The INR variability is an equal predictor as TTR of the combined endpoint of thromboembolism, major bleeding and death, and adds important information on top of TTR in patients with MHV.

Prophylactic doses of low-molecular weight heparin as periprocedural bridging therapy in mechanical heart valve patients

BACKGROUND Mechanical heart valve (MHV) patients undergoing invasive procedures necessitating an interruption of their lifelong anticoagulant therapy, often require bridging with low-molecular weight heparin (LMWH) or unfractionated heparin. The aim of this study was to assess whether bridging MHV patients with prophylactic doses of LMWH undergoing invasive, elective procedures is a safe and effective method. METHOD This observational cohort study included all MHV patients on vitamin K anticoagulant therapy in Malmö, registered and monitored via AuriculA (the Swedish national quality registry for atrial fibrillation and anticoagulation), between 1/1/2008 and 31/12/2011. Inclusion criteria were periprocedural bridging therapies conducted via AuriculA. Primary endpoints were mortality, thromboembolic (TE) events or major bleedings (MBE) within 30 days of bridging. RESULTS During the study period, 210 patients had undergone 434 bridging therapies managed via AuriculA; 203 due to subtherapeutic INR-values were excluded. The remaining 231 periprocedural bridging therapies were included. All were bridged with prophylactic doses of LMWH. When comparing patients with aortic and/or mitral valve replacements undergoing low- or high-risk interventions, only number of days bridged for a low-risk intervention differed significantly. Patients with a mitral or mitral and aortic valve replacement were bridged for a longer period (p=0.023). No TE events, 1 death (0.4%) and 3 MBEs (1.3%) occurred related to periprocedural bridging. CONCLUSION Our study shows a low rate of MBEs, deaths and no TE events when bridging MHV patients undergoing invasive, elective procedures with prophylactic doses of LMWH.