Is the time in therapeutic range using the ratio of tests equivalent to the Rosendaal method?

Clinical outcomes of bileaflet St. Jude Medical and tilting disc TTK Chitra mechanical heart valve prosthesis: A comparative study

BACKGROUND

Comparative data on the clinical outcomes of TTK Chitra mechanical heart valve prosthesis (CHVP), an indigenously developed low-cost tilting disc valve and commonly used bileaflet valve, the St. Jude medical (SJM) prosthesis are sparse.

METHODS

We conducted a retrospective follow-up study of consecutive patients undergoing mitral (MVR) and aortic valve replacement (AVR) with SJM or CHVP mechanical prostheses over a 6-year period at our institution.

RESULTS

Seven hundred and thirty-five patients who underwent isolated MVR (n = 510) or AVR (n = 225) were included in the study. Patients with CHVP were younger and belonged to a lower socioeconomic class. The study cohort was followed-up for 2836 patient-years (SJM: 1865.1, CHVP: 971.0). All-cause mortality (p = 0.894), valve-related mortality (p = 0.681), prosthetic valve thrombosis (p = 0.155), embolism (p = 0.210), hemorrhage (p = 0.959) and infective endocarditis (IE, p = 0.084) were similar between both valve on follow-up. Estimated event free survival was 2302 ± 1 days in SJM as compared to 2484 ± 65 days in CHVP group (p = 0.393). Valve type was not an independent predictor of adverse events after adjusting for baseline data, time in therapeutic range and aspirin use. Subgroup analysis of patients who underwent MVR and AVR showed similar functional improvement and outcomes, except for a higher incidence of IE with SJM at the aortic position (p = 0.041).

CONCLUSION

The indigenously developed, low-cost CHVP has comparable midterm clinical performance as SJM in aortic or mitral positions.

International Normalized Ratio Test Frequency in Left Ventricular Assist Device Patients Affects Anticoagulation Quality and Adverse Events

Anticoagulation therapy in patients using left ventricular assist device (LVAD) is essential to reduce hemocompatibility related adverse events (HRAEs). Vitamin K-antagonist dosage must be adapted and monitored by INR point-of-care testing (POCT) in outpatients. The study aims to determine if the frequency of INR POCT in LVAD outpatients has an influence on the quality of anticoagulation therapy (ACQ), HRAEs, and outcomes. This retrospective study included n = 48 patients who received LVAD implantation (HMII, HM3, and HVAD) between 2013 and 2017. ACQ (% of INR tests in range, PTR), outcomes and HRAEs using Kaplan-Meier curves were compared in a daily (n = 36) and 3×/week (n = 12) INR POCT group. Further, based on the achieved PTR ranging from 0-60% (poor), 61-70% (acceptable), and 71-100% (well controlled), HRAEs and outcomes were compared. Daily and 3×/week groups were similar in perioperative risk factors and INR target (p = 0.28). Freedom from any HRAE (38.9% vs. 25.0%, p = 0.44), any readmission (72.2% vs. 75.0%, p = 0.97), and 1 year survival (91.7% vs. 91.7%, p = 0.98) were comparable in both groups. The PTR was significantly higher with the daily self-assessments (73.5% vs. 68.4%, p = 0.006). Well vs. poorly controlled INR POCT patients more often had (p = 0.01) a daily POCT frequency (92%) vs. poorly controlled (54%) and significantly higher freedom from neurologic events (96.0 vs. 69.2%, p = 0.024) as well as hemorrhagic strokes (100% vs. 76.9%, p = 0.011). Well-controlled anticoagulation of LVAD outpatients is associated with less neurologic events. The frequency of INR POCT could be one of the key factors in the reduction of HRAEs, so future prospective, large-scale studies should help to clarify the effects.

Clinical Impact of the Time in Therapeutic Range on Early Hospital Readmission in Patients with Acute Heart Failure Treated with Oral Anticoagulation in Internal Medicine

Background and objectives: Patients with heart failure (HF) often present with non-valvular atrial fibrillation and require oral anticoagulation with coumarin anticoagulants such as acenocoumarol. The objective of this study was to evaluate the relationship between time in therapeutic range (TTR) and the risk of early readmission. Materials and Methods: A retrospective descriptive study was carried out on hospitalized patients with a diagnosis of HF between 2014 and 2018 who had adverse effects due to oral anticoagulation with acenocoumarol (underdosing, overdosing, or hemorrhage). Clinical, analytical, therapeutic, and prognostic variables were collected. TTR is defined as the duration of time in which the patient’s International Normalized Ratio (INR) values were within a desired range. Early readmission was defined as readmission within 30 days after hospital discharge. Patients were divided into two groups depending on whether or not they had a TTR less than 60% (TTR < 60%) over the 6 months prior to the adverse event. Results: In the cohort of 304 patients, the mean age was 82 years, 59.9% of the patients were female, and 54.6% had a TTR < 60%. Patients with TTR < 60% had a higher HAS-BLED score (4.04 vs. 2.59; p < 0.001) and INR (6 vs. 5.31; p < 0.05) but lower hemoglobin (11.67 vs. 12.22 g/dL; p < 0.05). TTR < 60% was associated with early readmission after multivariate analysis (OR: 2.05 (CI 95%: 1.16–3.61)). They also had a higher percentage of hemorrhagic events and in-hospital mortality but without reaching statistical significance. Conclusions: Patients with HF and adverse events due to acenocoumarol often have poor INR control, which is independently associated with a higher risk of early readmission.

Quality of initial anticoagulant treatment and risk of CTEPH after acute pulmonary embolism

BACKGROUND

The pathophysiology of chronic thromboembolic pulmonary hypertension (CTEPH) is not fully understood. Poor-quality anticoagulation may contribute to a higher risk of CTEPH after acute pulmonary embolism (PE), partly explaining the transition from acute PE to CTEPH. We assessed the association between the time in therapeutic range (TTR) of vitamin-K antagonist (VKA) treatment and incidence of CTEPH after a PE diagnosis.

METHODS

Case-control study in which the time spent in, under and above therapeutic range was calculated in 44 PE patients who were subsequently diagnosed with CTEPH (cases). Controls comprised 150 consecutive PE patients in whom echocardiograms two years later did not show pulmonary hypertension. All patients were treated with VKA for at least 6 months after the PE diagnosis. Time in (TTR), under and above range were calculated. Mean differences between cases and controls were estimated by linear regression.

RESULTS

Mean TTR during the initial 6-month treatment period was 72% in cases versus 78% in controls (mean difference -6%, 95%CI -12 to -0.1), mainly explained by more time above the therapeutic range in the cases. Mean difference of time under range was 0% (95%CI -6 to 7) and 2% (95CI% -3 to 7) during the first 3 and 6 months, respectively. In a multivariable model, adjusted odds ratios (ORs) for CTEPH were around unity considering different thresholds for 'poor anticoagulation', i.e. TTR <50%, <60% and <70%.

CONCLUSION

Subtherapeutic initial anticoagulation was not more prevalent among PE patients diagnosed with CTEPH than in those who did not develop CTEPH.

Time in the Therapeutic Range for Assessing Anticoagulation Quality in Patients Receiving Continuous Unfractionated Heparin

Due to variable pharmacokinetic properties, therapeutic anticoagulation with continuous unfractionated heparin (UFH) requires ongoing laboratory monitoring, generally with activated partial thromboplastin time (aPTT). In the ambulatory setting, clinicians who manage warfarin therapy often use time in the therapeutic range (TTR) to estimate a percentage of time the international normalized ratio is therapeutic. We applied the TTR concept to aPTT monitoring for therapeutic UFH and used 2 methodologies for estimation: percentage of aPTT values in range (%aIR) and a modification of the Rosendaal method (mod-Rosendaal). This study included adult inpatients admitted between September 30, 2015, and September 30, 2016, at Brigham and Women’s Hospital. For each patient, all available aPTT values were extracted to calculate 2 individual TTRs according to each methodology. Comparison between methods was performed using Student t test, and correlation was assessed with simple linear regression. A total of 255 patients were included in this study. The major outcome of TTR estimation was significantly higher using mod-Rosendaal (43.7% [26.5%]) versus %aIR (37.7% [25.7%], P = .012) by a mean difference of 6% points (95% confidence interval: 1.3-10.7). Time in the therapeutic range estimated by mod-Rosendaal significantly correlated with those estimated by %aIR (r = 0.84, P < .001). Further studies should evaluate the correlation between TTR and clinical outcomes and establish a benchmark for quality therapeutic anticoagulation with continuous UFH.

Clinical usefulness of the SAMe-TT2R2 score: A systematic review and simulation meta-analysis

Background

Vitamin K antagonist (VKA) therapy is safer and more effective when patients have a high time within the therapeutic range and low international normalised ratio variability. The SAMe-TT₂R₂ score aims to identify those at risk for poor VKA control.

Objectives

To evaluate the predictive value and clinical usefulness of the SAMe-TT₂R₂ score to identify those at risk for poor VKA control.

Methods

We performed a systematic review in MEDLINE and Embase for original research papers assessing the SAMe-TT₂R₂’s relation to poor TTR. We performed a meta-analysis where scores ≥ 2 and ≥ 3 predicting TTR < 70%. When studies evaluated other cutoffs for TTR or SAMe-TT₂R₂, they were harmonised by multiple simulations with patient characteristics from the individual studies, if the data were available.

Results

16 studies were identified and used in the meta-analysis: 4 and 2 times directly, 8 and 8 times harmonised for scores ≥ 2 and ≥ 3, respectively (not all studies provided information about both cutoffs). The sensitivities and specificities were too heterogeneous to pool. The positive likelihood ratios were 1.25 (1.14-1.38) for a score ≥ 2, and 1.24 (1.09-1.40) for a score ≥ 3; the negative ones were 0.87 (0.82-0.93) and 0.96 (0.91-1.02), respectively. This shows that the post-test probabilities hardly differ from the prior probability (prevalence).

Conclusion

The SAMe-TT₂R₂ score does predict low TTR, but the effect is small. Its effect on individual patients is too limited to be clinically useful.

Control of anticoagulation with vitamin K antagonists: overestimation of median time in therapeutic range when assessed by linear interpolation

Patients receiving vitamin K–antagonists are monitored by regular assessment of the International Normalized Ratio (INR). There are two popular methods for therapeutic control of anticoagulation in patient groups: 1) Time in Therapeutic Range (TTR) assessed by linear interpolation of successive INR measurements; 2) the cross-sectional proportion (CSP) of all patients’ last INRs within range. The purpose of the present study is to compare the two methods using data from 53 Dutch Thrombosis Centres and to develop a semi-quantitative model for TTR based on different types of INR change. Different groups of around 400,000 patients in four consecutive years were evaluated: patients in the induction phase, short-term, long-term, low-target range, high-target range, receiving either acenocoumarol or phenprocoumon, and performing self-management. Each Centre provided TTR and CSP results for each patient group. TTR and CSP were compared using the Wilcoxon signed-rank test. Separately, we analysed the relationship between consecutive INR results regarding in or out of range and their frequency of occurrence in patients of two different cohorts. Good correlation was observed between TTR and CSP (correlation coefficient 0.694–0.950 in low-target range). In long-term acenocoumarol patients (low-target range) the median TTR was significantly higher than CSP (80.0 % and 78.7 %, respectively; p<0.001). In long-term phenprocoumon patients (low-target range) there was no significant difference between median TTR (83.0 %) and median CSP (82.6 %). In conclusion, the correlation between TTR assessed by linear interpolation and CSP was good. TTR assessed by linear interpolation was higher than CSP in patients on acenocoumarol.