SummaryBackgroundInfliximab and adalimumab have established roles in inflammatory bowel disease (IBD) therapy. UK regulators mandate reassessment after 12 months' anti‐TNF therapy for IBD, with consideration of treatment withdrawal. There is a need for more data to establish the relapse rates following treatment cessation.AimTo establish outcomes following anti‐TNF withdrawal for sustained remission using new data from a large UK cohort, and assimilation of all available literature for systematic review and meta‐analysis.MethodsA retrospective observational study was performed on 166 patients with IBD (146 with Crohn's disease (CD) and 20 with ulcerative colitis [UC) and IBD unclassified (IBDU)] withdrawn from anti‐TNF for sustained remission. Meta‐analysis was undertaken of all published studies incorporating 11 further cohorts totalling 746 patients (624 CD, 122 UC).ResultsRelapse rates in the UK cohort were 36% by 1 year and 56% by 2 years for CD, and 42% by 1 year and 47% by 2 years for UC/IBDU. Increased relapse risk in CD was associated with age at diagnosis [hazard ratio (HR) 2.78 for age <22 years], white cell count (HR 3.22 for >5.25 × 109/L) and faecal calprotectin (HR 2.95 for >50 μg/g) at drug withdrawal. Neither continued immunomodulators nor endoscopic remission were predictors. In the meta‐analysis, estimated 1‐year relapse rates were 39% and 35% for CD and UC/IBDU respectively. Retreatment with anti‐TNF was successful in 88% for CD and 76% UC/IBDU.ConclusionsAssimilation of all available data reveals remarkable homogeneity. Approximately one‐third of patients with IBD flare within 12 months of withdrawal of anti‐TNF therapy for sustained remission.
Considerable variability exists in how individual patients respond to oral antiplatelet therapy, specifically to aspirin and to P2Y(12)-receptor inhibitors such as clopidogrel. This variability translates to differences in clinical outcomes and might in part be as a result of common variation within genes that are involved in the absorption, metabolic activation, and biological activity of these medications. The field of pharmacogenetics has yielded several genetic loci that predict variation in patient response to antiplatelet therapies. The most robust data indicate an association between loss-of-function alleles of the CYP2C19 gene and adverse outcomes among high-risk patients treated with clopidogrel. However, several fundamental questions surrounding the information gained from genotyping and the efficacy of modifying therapy on the basis of testing remain unanswered. Routine genetic testing for platelet responsiveness cannot, therefore, be recommended for clinical decision-making. Ongoing and future clinical trials might provide evidence to support a change in practice towards pharmacogenetic-based selection of antiplatelet therapy.
During exercise, β-adrenergic receptors are activated throughout the body. In healthy humans, the net effect of β-adrenergic stimulation is an increase in coronary blood flow. However, the role of vascular β1 vs. β2 receptors in coronary exercise hyperemia is not clear. In this study, we simultaneously measured noninvasive indexes of myocardial oxygen supply (i.e., blood velocity in the left anterior descending coronary artery; Doppler echocardiography) and demand [i.e., rate pressure product (RPP) = heart rate × systolic blood pressure) and tested the hypothesis that β1 blockade with esmolol improves coronary exercise hyperemia compared with nonselective β-blockade with propranolol. Eight healthy young men received intravenous infusions of esmolol, propranolol, and saline on three separate days in a single-blind, randomized, crossover design. During each infusion, subjects performed isometric handgrip exercise until fatigue. Blood pressure, heart rate, and coronary blood velocity (CBV) were measured continuously, and RPP was calculated. Changes in parameters from baseline were compared with paired -tests. Esmolol (Δ = 3296 ± 1204) and propranolol (Δ = 2997 ± 699) caused similar reductions in peak RPP compared with saline (Δ = 5384 ± 1865). In support of our hypothesis, ΔCBV with esmolol was significantly greater than with propranolol (7.3 ± 2.4 vs. 4.5 ± 1.6 cm/s; = 0.002). This effect was also evident when normalizing ΔCBV to ΔRPP. In summary, not only does selective β1 blockade reduce myocardial oxygen demand during exercise, but it also unveils β2-receptor-mediated coronary exercise hyperemia. In this study, we evaluated the role of vascular β1 vs. β2 receptors in coronary exercise hyperemia in a single-blind, randomized, crossover study in healthy men. In response to isometric handgrip exercise, blood flow velocity in the left anterior descending coronary artery was significantly greater with esmolol compared with propranolol. These findings increase our understanding of the individual and combined roles of coronary β1 and β2 adrenergic receptors in humans.
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