Myocardial extravascular extracellular volume fraction measurement by gadolinium cardiovascular magnetic resonance in humans: slow infusion versus bolus

<p>Abstract</p> <p>Background</p> <p>Myocardial extravascular extracellular volume fraction (Ve) measures quantify diffuse fibrosis not readily detectable by conventional late gadolinium (Gd) enhancement (LGE). Ve measurement requires steady state equilibrium between plasma and interstitial Gd contrast. While a constant infusion produces steady state, it is unclear whether a simple bolus can do the same. Given the relatively slow clearance of Gd, we hypothesized that a bolus technique accurately measures Ve, thus facilitating integration of myocardial fibrosis quantification into cardiovascular magnetic resonance (CMR) workflow routines. Assuming equivalence between techniques, we further hypothesized that Ve measures would be reproducible across scans.</p> <p>Methods</p> <p>In 10 volunteers (ages 20-81, median 33 yr, 3 females), we compared serial Ve measures from a single short axis slice from two scans: first, during a constant infusion, and second, 12-50 min after a bolus (0.2 mmol/kg gadoteridol) on another day. Steady state during infusion was defined when serial blood and myocardial T1 data varied <5%. We measured T1 on a 1.5 T Siemens scanner using a single-shot modified Look Locker inversion recovery sequence (MOLLI) with balanced SSFP. To shorten breath hold times, T1 values were measured with a shorter sampling scheme that was validated with spin echo relaxometry (TR = 15 sec) in CuSO4-Agar phantoms. Serial infusion vs. bolus Ve measures (n = 205) from the 10 subjects were compared with generalized estimating equations (GEE) with exchangeable correlation matrices. LGE images were also acquired 12-30 minutes after the bolus.</p> <p>Results</p> <p>No subject exhibited LGE near the short axis slices where Ve was measured. The Ve range was 19.3-29.2% and 18.4-29.1% by constant infusion and bolus, respectively. In GEE models, serial Ve measures by constant infusion and bolus did not differ significantly (difference = 0.1%, p = 0.38). For both techniques, Ve was strongly related to age (p < 0.01 for both) in GEE models, even after adjusting for heart rate. Both techniques identically sorted older individuals with higher mean Ve values.</p> <p>Conclusion</p> <p>Myocardial Ve can be measured reliably and accurately 12-50 minutes after a simple bolus. Ve measures are also reproducible across CMR scans. Ve estimation can be integrated into CMR workflow easily, which may simplify research applications involving the quantification of myocardial fibrosis.</p

Cardiovascular magnetic resonance in systemic hypertension

Systemic hypertension is a highly prevalent potentially modifiable cardiovascular risk factor. Imaging plays an important role in the diagnosis of underlying causes for hypertension, in assessing cardiovascular complications of hypertension, and in understanding the pathophysiology of the disease process. Cardiovascular magnetic resonance (CMR) provides accurate and reproducible measures of ventricular volumes, mass, function and haemodynamics as well as uniquely allowing tissue characterization of diffuse and focal fibrosis. In addition, CMR is well suited for exclusion of common secondary causes for hypertension. We review the current and emerging clinical and research applications of CMR in hypertension

Non-persistence and non-adherence to MTX therapy in patients with rheumatoid arthritis: a retrospective cohort study based on German RA patients

Sabrina M&uuml;ller,1 Thomas Wilke,1 Andreas Fuchs,2 Ulf Maywald,2 Jan-Paul Flacke,3 Harald Heinisch,4 Klaus Kr&uuml;ger5 1Institute for Pharmacoeconomics and Medication Logistics, University of Wismar, Wismar, 2AOK PLUS, Dresden, 3Roche Pharma AG, Grenzach-Wyhlen, 4Chugai Pharma Europe Ltd, Frankfurt/M, 5Praxiszentrum St Bonifatius, Munich, Germany Objective: This study aimed to assess the level of nonpersistence (NP) and nonadherence (NA) to methotrexate (MTX) therapy in German patients with rheumatoid arthritis (RA). Materials and methods: Based on German claims data, RA patients who received a MTX therapy (subgroup: treatment-naive patients) were analyzed. NP was defined as treatment gap &gt;12&nbsp;weeks. Regarding NA, it is the overall medication possession ratio (MPR) during an observational period of 12 or 24&nbsp;months after therapy, and the MPR is calculated only for the periods of therapy continuation; NA was defined as MPR &lt;80%.Results: A total of 7,146 RA patients who received at least one MTX prescription (subgroup: 1,211 treatment-naive patients) could be observed (mean age: 64.4&nbsp;years, 73.6% female). Percentage of NP patients among MTX-naive patients after 6, 12 and 18&nbsp;months was 16.7%, 34.0% and 36.7%, respectively. After MTX therapy discontinuation, 39.9% had restarted their MTX therapy, 13.8% had received another non-MTX synthetic disease-modifying antirheumatic drug (sDMARD), 8.1% had biological DMARD (bDMARD) and 49.2% had not received any DMARD prescription at all. Overall, 12- and 24-month MPRs for MTX therapy were 83.0% and 76.5% with a percentage of NA patients of 25.8% and 33.8%, respectively. During periods of general treatment continuation, the percentage of patients with an MPR &lt;80% was 6.5%.Conclusion: NP to MTX treatment seems to be common in one-fourth of German patients with RA. An additional number of patients, at least 6.5%, are also affected by NA. A considerable percentage of RA patients who discontinued MTX therapy do not receive any follow-up DMARD therapy. Keywords: rheumatoid arthritis, RA, MTX therapy, adherence to MTX therapy, persistence with MTX therapy, discontinuation of MTX therapy&nbsp