Safety of regadenoson as a pharmacologic stress agent for myocardial perfusion imaging in chronic kidney disease patients not on hemodialysis

Pharmacological strategies for mitigating anti-TNF biologic immunogenicity in rheumatoid arthritis patients

Tumor necrosis factor alpha (TNFα) inhibitors are a mainstay of treatment for rheumatoid arthritis (RA) patients after failed responses to conventional disease-modifying antirheumatic drugs (DMARDs). Despite the clinical efficacy of TNFα inhibitors (TNFi), many RA patients experience TNFi treatment failure due to the development of anti-drug antibodies (ADAs) that can neutralize drug levels and lead to RA disease relapse. Methotrexate (MTX) therapy with concomitant TNFα inhibitors decreases the risk of TNFi immunogenicity, but additional and/or alternative strategies are needed to reduce MTX-associated toxicities and to further increase its potency for preventing TNFα inhibitor immunogenicity. In this review, we highlight the limitations of MTX for mitigating TNFα inhibitor immunogenicity, and we discuss potential alternative pharmacological targets for decreasing the risk of immunogenicity during TNFα inhibitor therapy based on the key kinases, second messengers, and shared signaling mechanisms of lymphocyte receptor signaling.

The prognostic utility of regadenoson SPECT myocardial perfusion imaging in patients with end-stage renal disease: The largest cohort to date

BACKGROUND

There are limited data on the prognostic utility of regadenoson SPECT myocardial perfusion imaging (MPI) in patients with end-stage renal disease (ESRD).

METHODS AND RESULTS

In a single-center, retrospective study, we analyzed consecutive ESRD patients who underwent regadenoson SPECT-MPI. The severity of MPI abnormalities and ischemic burden were determined quantitatively. The primary endpoint was major adverse cardiac events (MACE), defined as the composite of cardiac death or myocardial infarction. Among 1,227 subjects (mean age 54 ± 13 years, 47% men), 60 (5%) MACE were observed during a mean follow-up of 2.5 ± 1.8 years. The presence and severity of MPI abnormalities and ischemic burden were associated with a stepwise increase in MACE risk. Abnormal MPI (SSS ≥ 4) was associated with increased MACE risk, independent and incremental to relevant clinical covariates; adjusted hazard ratio, 1.95; 95% confidence interval, 1.15-3.32; Δχ2 = 5.97; P = .013. Myocardial ischemia (SDS ≥ 2) was associated with a trend towards increased MACE risk; adjusted hazard ratio, 1.63; 95% confidence interval, 0.96-2.77; Δχ2 = 3.12; P = .072.

CONCLUSION

In the largest cohort to date, we demonstrated the incremental prognostic value of abnormal MPI in predicting MACE risk in ESRD patients. Given its size, our study provides improved risk estimates in this population compared to previous reports.

Asystole following Regadenoson administration: Review of literature, risk factors and management

Regadenoson, a selective A2A receptor agonist, is widely used for vasodilator stress myocardial perfusion imaging and has a superior adverse effect profile when compared with other agents. However, with widespread use, there have been several reported cases of Regadenoson induced bradyarrhythmias and even asystole in patients with no known conduction system disease. In this article, we report a case of asystole following Regadenoson administration, evaluate mechanisms and risk factors for Regadenoson induced bradyarrhythmias to better identify patients at risk. We also review the available treatment options and propose recommendations for limiting its risk.

Role of Cardiac A2A Receptors Under Normal and Pathophysiological Conditions

This review presents an overview of cardiac A2A-adenosine receptors The localization of A2A-AR in the various cell types that encompass the heart and the role they play in force regulation in various mammalian species are depicted. The putative signal transduction systems of A2A-AR in cells in the living heart, as well as the known interactions of A2A-AR with membrane-bound receptors, will be addressed. The possible role that the receptors play in some relevant cardiac pathologies, such as persistent or transient ischemia, hypoxia, sepsis, hypertension, cardiac hypertrophy, and arrhythmias, will be reviewed. Moreover, the cardiac utility of A2A-AR as therapeutic targets for agonistic and antagonistic drugs will be discussed. Gaps in our knowledge about the cardiac function of A2A-AR and future research needs will be identified and formulated.

Evidence for Arrhythmogenic Effects of A2A-Adenosine Receptors

Adenosine can be released from the heart and may stimulate four different cardiac adenosine receptors. A receptor subtype that couples to the generation of cyclic adenosine monophosphate (cAMP) is the A_2A-adenosine receptor (A_2A-AR). To better understand its role in cardiac function, we studied mechanical and electrophysiological effects in transgenic mice that overexpress the human A_2A-AR in cardiomyocytes (A_2A-TG). We used isolated preparations from the left atrium, the right atrium, isolated perfused hearts with surface electrocardiogram (ECG) recording, and surface body ECG recordings of living mice. The hypothesized arrhythmogenic effects of transgenicity per se and A_2A-AR stimulation were studied. We noted an increase in the incidence of supraventricular and ventricular arrhythmias under these conditions in A_2A-TG. Moreover, we noted that the A_2A-AR agonist CGS 21680 exerted positive inotropic effect in isolated human electrically driven (1 Hz) right atrial trabeculae carneae. We conclude that A_2A-ARs are functional not only in A_2A-TG but also in isolated human atrial preparations. A_2A-ARs in A_2A-TG per se and their stimulation can lead to cardiac arrhythmias not only in isolated cardiac preparations from A_2A-TG but also in living A_2A-TG.

Incidence of atrioventricular block with vasodilator stress SPECT: A meta-analysis

BACKGROUND

Adenosine or regadenoson are often used with pharmacologic stress testing. Adenosine may trigger atrioventricular block (AVB). Despite its higher selectivity, regadenoson has also been associated with AVB. We studied the incidence of de novo AVB with these agents.

METHODS

A comprehensive search of SCOPUS was performed from inception to March 2016. Studies of at least 10 patients, using adenosine and/or regadenoson with SPECT-MPI, reporting rates of AVB were selected for further review.

RESULTS

Thirty four studies were pooled including 22,957 patients. Adenosine was used in 21 studies and regadenoson in 15. Both were administered in two studies. The estimated incidence of overall and high-grade AVB was 3.81% (95% CI 1.99%-6.19%) and 1.93% (95% CI 0.77%-3.59%), respectively. The incidence of AVB (8.58%; 95% CI 5.55%-12.21% vs 0.30%; 95% CI 0.04%-0.82%, respectively, P < .001) and high-grade AVB (5.21%; 95% CI 2.81%-8.30% vs 0.05%; 95% CI < .001%-0.19% respectively, P < .001) were higher with adenosine compared to regadenoson.

CONCLUSION

AVB is seen in about 4% of patients undergoing vasodilator stress test. Both overall and high-grade AVB are more frequent with adenosine compared to regadenoson.

Mortality and morbidity after hepatic resection in patients undergoing hemodialysis: analysis of a national inpatient database in Japan

BACKGROUND

Whether patients undergoing hemodialysis have greater risks of mortality and morbidity after hepatic resection remains unclear.

METHODS

We used the Diagnosis Procedure Combination database, a national inpatient database in Japan, to identify patients who underwent hepatic resection from July 2010 to March 2014. Propensity scorematching analysis was performed to compare morbidity and mortality between patients with and without hemodialysis.

RESULTS

Of 53,651 eligible patients, 498 (0.93%) underwent hemodialysis. Propensity score-matching analysis indicated greater in-hospital mortality in patients with than without hemodialysis (8.6% vs 2.0%; P < .001). Patients undergoing hemodialysis had more postoperative major complications than did patients not undergoing hemodialysis (18.1% vs 7.4%; P < .001). In the subgroup analyses for in-hospital mortality, the odds ratio of hemodialysis was 2.36 (95% confidence interval, 0.78-6.59; P = .067) in limited resection, 4.61 (95% confidence interval, 1.90-11.2; P < .001) in segmentectomy or sectoriectomy, and 5.58 (95% confidence interval, 3.40-14.9; P < .001) in bisectoriectomy or trisectoriectomy. In the age subgroup analyses, the odds ratio of hemodialysis was 4.38 (95% confidence interval, 2.66-7.21; P < .001) in patients aged <80 years and 7.20 (95% confidence interval, 1.55-36.7; P = .0011) in those aged ≥80 years.

CONCLUSION

Patients undergoing hemodialysis had a substantially increased risk of mortality and morbidity after hepatic resection. Surgical indications for major hepatectomy in patients undergoing hemodialysis who are ≥80 years of age may be limited and require careful scrutiny.

Influence of hemodialysis on regadenoson clearance in an in vitro hemodialysis model

BACKGROUND

Regadenoson is a novel pharmacological stress agent whose disposition during hemodialysis is not known. The purpose of this study was to determine the clearance of regadenoson under varying dialytic conditions using an in vitro hemodialysis model.

METHODS AND RESULTS

Whole human blood was used to analyze the effect of hemodialysis on the clearance of regadenoson. Regadenoson transmembrane clearance (CLD) was assessed for both a standard permeability and a high permeability polysulfone hemodialyzer with blood/dialysate flow rates of 300/600 and 400/800 mL/min. A two-tailed, paired Student's t test was used to compare regadenoson CLD between hemodialyzer types and flow rates. The mean ± SD regadenoson CLD values ranged between 62.5 ± 11.8 and 89.1 ± 24.0 mL/min for all dialytic conditions. There was no significant difference in regadenoson CLD between hemodialyzer types and flow rates (p > .05).

CONCLUSIONS

Hemodialysis enhances the clearance of regadenoson independent of hemodialyzer permeability and blood/dialysate flow rate. This clearance is modest relative to total body clearance and is unlikely to produce a clinically significant outcome.

Regadenoson use in chronic kidney disease and end-stage renal disease: A focused review

Regadenoson is a selective A2A adenosine receptor agonist that has been approved as a vasodilator stress agent with single-photon emission-computed tomography (SPECT) myocardial perfusion imaging (MPI). Since its approval by the Food and Drug Administration (FDA) in 2008, it has become the most commonly used pharmacologic stress agent with SPECT-MPI. Given that it is predominantly renally excreted, its use in patients with chronic kidney disease has been the subject of active post-marketing clinical research. Until recently, prescribing information regarding the use of regadenoson in patients with end-stage renal disease (ESRD) was not defined in the package insert. Based on accumulating data since its initial approval, the FDA has recently outlined the use of regadenoson in patients with ESRD in a label update on January 17, 2017. In this review, we discuss the evidence leading to the recent label update, focusing on the pharmacokinetics of regadenoson in patients with impaired kidney function, the safety and tolerability of regadenoson in patients with chronic kidney disease and ESRD, and the prognostic value of regadenoson stress MPI in this patient population.

Regadenoson stress for myocardial perfusion imaging

Noninvasive functional imaging plays a major role in the diagnosis of hemodynamically significant coronary artery disease (CAD) by means of the detection of abnormal myocardial perfusion. For this, cardiac stressors are essential as they induce hypoperfusion in the presence of flow-limiting coronary stenosis. Several pharmacological stressors are currently available and it is important that clinicians who are involved in the care and management of patients with CAD become familiar with their indications, contraindications and protocols. Among the primary coronary vasodilator agents, regadenoson is increasingly used as the default stressor or as an alternative to other modalities of stress. This article provides an updated review of regadenoson stress for the assessment of patients with suspected or known CAD and describes its pharmacological properties, stress protocol, efficacy and safety profile.

Severe chronic kidney disease as a predictor of benefit from aminophylline administration in patients undergoing regadenoson stress myocardial perfusion imaging: A substudy of the ASSUAGE and ASSUAGE-CKD trials

BACKGROUND

Regadenoson is predominantly renally metabolized. Patients with severe chronic kidney disease (CKD) experience more frequent gastrointestinal adverse effects (AE) from regadenoson. Aminophylline use following regadenoson reduces the incidence of regadenoson-related AE. We investigated whether patients with severe CKD receive incremental benefit from aminophylline administration in reducing regadenoson AE.

METHODS

We performed post hoc analysis of the pooled database of the ASSUAGE and ASSUAGE-CKD trials. These were randomized placebo-controlled clinical trials which tested the benefit of intravenous aminophylline vs placebo after regadenoson injection in patients undergoing a clinically indicated stress MPI. Patients were categorized into two treatment arms: aminophylline vs placebo; and two groups: Severe CKD (GFR < 30 mL·min(-1)/1.73 m(2) or dialysis) and Control (GFR ≥ 30 mL·min(-1)/1.73 m(2)). The study endpoints were gastrointestinal AE, non-gastrointestinal AE and composite of any regadenoson AE.

RESULT

The pooled database of the two trials yielded 548 patients, of whom 274 patients received aminophylline and 274 received placebo. Aminophylline was associated with greater absolute risk reduction (ARR) in gastrointestinal AE among patients with severe CKD vs controls (25% vs 4%, p < .001). A significant interaction was identified between severe CKD and aminophylline in reducing gastrointestinal AE (p = .007), indicating greater reduction in gastrointestinal AE with aminophylline use among patients with severe CKD. Aminophylline use was associated with a trend toward greater ARR in any regadenoson-related AE (32% vs 21%, p = .08).

CONCLUSION

Aminophylline is associated with incremental benefit in reducing gastrointestinal AE in patients with severe CKD undergoing regadenoson stress MPI. Potentially, this population could be targeted for prophylactic administration of aminophylline in order to improve their overall experience with the test.

Safety and tolerability of regadenoson CMR

AIMS

Knowledge of adverse events associated with regadenoson perfusion cardiac magnetic resonance (CMR) and patient tolerability has implications for patient safety and staff training. We sought to assess the safety and tolerability of regadenoson stress CMR.

MATERIALS AND METHODS

A group of 728 consecutive patients (median age 58, 44% female) and 25 normal volunteers (median age 21, 24% female) were recruited from August 2009 to March 2012 using a prospective, cross-sectional study design. Subjects were stressed using fixed-dose regadenoson and imaged using a 1.5T MRI scanner. Symptoms and adverse events including death, myocardial infarction (MI), ventricular tachycardia (VT)/ventricular fibrillation (VF), hospitalization, arrhythmias, and haemodynamic stability were assessed.

RESULTS

There were no occurrences of death, MI, VT/VF, high-grade atrioventricular block, or stress-induced atrial fibrillation. Notable adverse events included one case of bronchospasm and one case of heart failure exacerbation resulting in hospitalization. The most common symptoms in patients were dyspnoea (30%, n = 217), chest discomfort (27%, n = 200), and headache (15%, n = 111). There was minimal change between baseline and peak systolic and diastolic blood pressure in both patients and volunteers (P > 0.05). A blunted heart rate response to regadenoson was noted in patients with body mass index (BMI) ≥ 30 kg/m(2) (P < 0.001), and diabetes (P = 0.001).

CONCLUSIONS

Regadenoson CMR is well tolerated and can be performed safely with few adverse events.

Comparison of hemodynamic and stress testing variables in patients undergoing regadenoson stress myocardial perfusion imaging to regadenoson with adjunctive low-level exercise myocardial perfusion imaging

BACKGROUND

Regadenoson (REG), a selective adenosine A2a receptor agonist, is becoming the preferred pharmacologic agent for stress myocardial perfusion imaging (MPI). Hemodynamic and stress variables, immediate safety and use of aminophylline when using REG combined with low-level exercise (REG WALK MPI) compared with REG MPI, have not been well studied and formed the basis of our study.

METHODS

Retrospective evaluation of patients who underwent REG MPI (n = 887) was compared to patients undergoing REG WALK MPI (n = 485) from January to November 2009. Patient demographics, hemodynamic parameters, REG MPI data, side effects, immediate major clinical events, and use of aminophylline were evaluated.

RESULTS

Patients in REG WALK MPI group tended to be younger, male and obese compared to patients in REG MPI group. REG WALK MPI patients had higher stress heart rate (103 ± 20.5 vs 84 ± 19 bpm, P = .001), higher heart rate reserve (36.3 ± 19 vs 14.7 ± 15.5 bpm, P < .001), and greater systolic blood pressure rise (4.8 ± 21.3 vs -8.9 ± 19.8 mm Hg, P < .001), compared to REG MPI patients. No major adverse events were reported immediately after REG WALK MPI. There were no differences in drug-related side effects in between the two groups; however, the use of aminophylline was lower in REG WALK MPI Group (5.6% vs 11.4%, P = .001).

CONCLUSION

REG WALK MPI gives more favorable hemodynamic response with lesser use of aminophylline and no increase in adverse events when compared with REG MPI.

Regadenoson: review of its established role in myocardial perfusion imaging and emerging applications

Myocardial perfusion imaging is a well-established noninvasive modality for the diagnosis and prognosis of coronary artery disease. The pharmacologic stress agents adenosine and dipyridamole are widely used in imaging studies, but cause undesirable side effects, like atrioventricular block and bronchospasm, due to their nonselective adenosine receptor activation. Furthermore, the mode of administration of these agents as a bolus infusion is less preferred. Regadenoson, an A2A adenosine receptor selective pharmacologic stress agent was approved in 2008 and is widely used instead of adenosine and dipyridamole. This article reviews regadenosons structure, mechanism of action, advantages over adenosine and dipyridamole, and its role in various patient populations undergoing stress perfusion imaging. Emerging applications where regadenoson could be of potential use are also explored.

The safety and tolerability of regadenoson in patients with end-stage renal disease: the first prospective evaluation

BACKGROUND

There has not been any prospective evaluation of the safety and tolerability of regadenoson (REG)-stress in patients with end-stage renal disease (ESRD).

METHODS

From the pooled database of two identically designed randomized, double-blinded, placebo-controlled clinical trials, ASSUAGE and ASSUAGE-CKD (IV-aminophylline vs placebo following REG-stress), we extracted the placebo-treated subjects to form 2 study groups: ESRD (dialysis or GFR < 15 mL/minute/1.73 m(2)) and control (GFR ≥ 30). The incidence of REG adverse effects and the hemodynamic and ECG responses to REG-stress were compared.

RESULTS

We identified 146 ESRD subjects and 97 controls. There was no significant difference in the incidence of the composite of any REG adverse effect [ESRD 108 (74%) vs control 73 (75%), P = .82]. ESRD patients seem to have excess incidences of diarrhea [42 (29%) vs 14 (14%), P = .009] and fewer events of dizziness [28 (19%) vs 43 (44%), P < .001]. There were no serious adverse events in either group. There was no significant difference in the incidence of ST-segment deviation, tachyarrhythmias, atrioventricular block, or hypotension.

CONCLUSION

This is the first prospective study to confirm the safety and tolerability of REG in patients with ESRD.

Prevalence and significance of electrocardiographic changes and side effect profile of regadenoson compared with adenosine during myocardial perfusion imaging

BACKGROUND

Significance of electrocardiogram (EKG) changes associated with regadenoson as well as side effects compared to adenosine in a real world, unselected population is unknown.

METHODS AND RESULTS

Three hundred ninety six consecutive patients undergoing either adenosine or regadenoson-based single-isotope (Technetium 99c) nuclear images were evaluated. A standard form documenting side effects was filled immediately following administration. The EKGs and nuclear scans were reviewed in a blinded-fashion. Commonest symptoms reported were flushing (64%), chest pain (36%) and dyspnea (36%). Flushing and chest pain were significantly more common with adenosine (73% vs. 57%, P < 0.01 and 53% vs. 47%, P = 0.06) and dyspnea more with regadenoson (40% vs. 31%, P = 0.05). Sixty (29%) patients carried a diagnosis of chronic bronchitis or asthma but only 4 (2 with each) required aminophylline. There was no significant correlation between chest pain induced by either agent or ischemia on nuclear imaging. EKG changes occurred infrequently (16% with regadenoson and 10% with adenosine), and had low sensitivity for detecting ischemia (7% for regadenoson and 11% for adenosine).

CONCLUSIONS

EKG changes with adenosine and regadenoson occur infrequently and have low sensitivity for detecting ischemia. Chest pain is frequently induced by both, and is not predictive of ischemia on nuclear imaging.

Attenuation of the side effect profile of regadenoson: a randomized double-blind placebo-controlled study with aminophylline in patients undergoing myocardial perfusion imaging and have severe chronic kidney disease--the ASSUAGE-CKD trial

A subgroup analysis of the ASSUAGE trial suggested that the standardized intravenous aminophylline administration following regadenoson-stress leads to substantial attenuation of regadenoson adverse-effects in patients with severe chronic kidney disease (CKD). In a randomized, double-blinded, placebo-controlled clinical trial of patients with stage 4 and 5 CKD, we compared the frequency and severity of regadenoson adverse-effects in those who received 75 mg of intravenous aminophylline versus a matching placebo administered 90 s post-radioisotope injection. Consecutive 300 patients with severe CKD (36% women; 86% end-stage renal disease; age 55 (±13) years) were randomized to receive aminophylline (n = 150) or placebo (n = 150). In the aminophylline arm, there was 65% reduction in the incidence of the primary endpoint of diarrhea (9 (6.0%) vs. 26 (17.3%), P = 0.002), 51% reduction in the secondary endpoint of any regadenoson adverse-effect (47 (31.3%) vs. 96 (64%), P < 0.001) and 70% reduction in headache (16 (10.7%) vs. 54 (36%), P < 0.001). The stress protocol was better tolerated in the aminophylline group (P = 0.008). The quantitative summed difference score, as a measure of stress-induced ischemic burden, was similar between the study groups (P = 0.51). In conclusion, the routine standardized administration of intravenous aminophylline in patients with severe CKD substantially reduces the frequency and severity of the adverse-effects associated with regadenoson-stress without changing the ischemic burden. [NCT01336140].