Safety of regadenoson in patients with end-stage liver disease

Cardiac imaging for the assessment of patients being evaluated for liver transplantation

Cardiac risk assessment prior to liver transplantation has become widely accepted. With the emergence of nonalcoholic steatohepatitis among the leading causes of end-stage liver disease and the steady rise of the age of liver transplant recipients, the burden of cardiovascular diseases has markedly increased in this population. Selecting appropriate liver transplant candidates is crucial due to the increasing demand for scarce donor organs. The use of noninvasive cardiac imaging for pre-operative assessment of the cardiovascular status of liver transplant recipients has been on the rise, yet the optimal assessment strategy remains an area of active debate. In this review, we examine the relevant literature pertaining to the diagnostic and prognostic applications of noninvasive cardiac imaging in this population. We also propose a simple literature-based evaluation algorithm for CAD surveillance in liver transplant candidates.

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.

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.

Safety and tolerability of intravenous regadenoson in healthy subjects: A randomized, repeat-dose, placebo-controlled study

BACKGROUND

Regadenoson is a selective A2A adenosine receptor agonist indicated for radionuclide myocardial perfusion imaging in patients unable to undergo adequate exercise stress. However, the safety, tolerability, and plasma concentrations associated with repeated doses have not previously been assessed.

METHOD AND RESULTS

Healthy males and females were randomized to receive intravenous regadenoson [100 μg (3 doses), 200 μg (3 doses), or 400 μg (2 doses)], or placebo (2 or 3 doses; 0.9% sodium chloride); all doses 10 minutes apart. The primary endpoint was vital sign measurements (blood pressure and heart rate). Secondary endpoints included 12-lead electrocardiogram measurements, clinical laboratory evaluations (hematology, chemistry, and urinalysis), and adverse events. Thirty-six subjects were randomized and completed the study. Plasma concentrations of regadenoson increased in a dose-related manner and with successive doses. No consistent effect was observed for systolic blood pressure, although diastolic blood pressure was slightly lower than placebo for all regadenoson groups. Transient, dose-dependent increases in heart rate were observed in all regadenoson groups. There were no serious adverse events; 27 adverse events occurred in 14 regadenoson-treated subjects vs two events in two placebo-treated subjects.

CONCLUSION

Repeated doses of regadenoson appeared to be safe and well tolerated in healthy subjects.

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.

Cardiac imaging for the assessment of patients being evaluated for kidney or liver transplantation

Cardiac risk assessment prior to kidney and liver transplantation is controversial. Given the paucity of available organs, selecting appropriate recipients with favorable short- and long-term cardiovascular risk profile is crucial. Using noninvasive cardiac imaging tools to guide cardiovascular risk assessment and management can also be challenging and controversial. In this article, we address the burden of coronary artery disease among kidney and liver transplant candidates and review the literature pertaining to the diagnostic accuracy and the prognostic value of noninvasive cardiac imaging techniques in this population.

[Regadenoson as a new stress agent in myocardial perfusion imaging. Initial experience in The Netherlands]

OBJECTIVE

Regadenoson is a recently approved selective adenosine-2A receptor agonist to induce pharmacological stress in myocardial perfusion imaging (MPI) procedures using a single bolus injection.

MATERIAL AND METHODS

We included 123 patients referred for MPI because of suspected coronary arterial disease (CAD). Of these, 66 patients underwent a regadenoson stress test and 57 patients underwent an adenosine stress test preceding standard myocardial SPECT imaging. Technicians, physicians and patients were asked to report their experience using questionnaires.

RESULTS

As compared to adenosine, regadenoson did not produce any atrio-ventricular block (0 vs. 10% with adenosine), but did produce minor tachycardia and minimal blood pressure changes while all other side effects were milder and shorter. There were fewer patients with severe complaints after taking regadenoson than adenosine (17% vs. 32%, respectively, p<0.01). The most frequent complaint reported was dyspnea, followed by flushing and chest pain. However, when they did occur, they usually disappeared rapidly. The overall symptom score, including severity and duration of side effects, was significantly lower after regadenoson than after adenosine (6.7±6.3 vs. 10.0±7.9, respectively; p<0.01.) SPECT imaging results were similar. The regadenoson procedure was faster and more practical.

CONCLUSION

Regadenoson, the new selective adenosine-2A receptor agonist, is a stress agent for MPI with a patient- and department friendly profile.

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.

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.

Accuracy of stress myocardial perfusion imaging to diagnose coronary artery disease in end stage liver disease patients

Patients with end-stage liver disease (ESLD) who also have underlying coronary artery disease (CAD) may be at increased risk for undergoing hemodynamically challenging orthotopic liver transplantation. Noninvasive single-photon emission computed tomographic (SPECT) imaging is often used to determine whether a patient with ESLD has unsuspected CAD. The objective of this study was to determine the accuracy of SPECT imaging for detection of CAD in patients with ESLD. Patients with ESLD who underwent coronary angiography and SPECT imaging before orthotopic liver transplantation were analyzed retrospectively. The predictive accuracy of clinical risk factors was calculated and compared to the results of SPECT imaging. There were 473 SPECT imaging studies. Adenosine SPECT imaging had a sensitivity of 62%, specificity of 82%, positive predictive value of 30%, and negative predictive value of 95% for diagnosing severe CAD. Regadenoson SPECT imaging had a sensitivity of 35%, specificity of 88%, positive predictive value of 23%, and negative predictive value of 93% for diagnosing severe CAD. The accuracy of a standard risk factor analysis showed no statistical difference in predicting CAD compared with adenosine (sensitivity McNemar's p = 0.48, specificity McNemar's p = 1.00) or regadenoson (sensitivity McNemar's p = 0.77, specificity McNemar's p = 1.00) SPECT studies. In conclusion, the 2 pharmaceutical agents had low sensitivity but high specificity for diagnosing CAD. However, because the sensitivity of the test is low, the chances of missing patients with ESLD with CAD is high, making SPECT imaging an inaccurate screening test. A standard risk factor analysis as a predictor for CAD in patients with ESLD is less expensive, has no radiation exposure, and is as accurate as SPECT imaging.

Regadenoson: a focused update

Since its approval by the Food and Drug Administration in 2008, regadenoson has become the most commonly used vasodilator in the United States. Previous reviews have summarized the pre-clinical and clinical data on the use of regadenoson for myocardial perfusion imaging (MPI). Since then, data have emerged on the safety of this agent in special groups of patients such as those with chronic kidney disease, airway disease (asthma and chronic obstructive pulmonary disease), and liver disease. There has also been recent interest in the use of regadenoson in hybrid protocols with exercise as a way to improve patient tolerance and image quality. Finally, although regadenoson was approved for clinical use based on the agreement rate of regadenoson MPI and adenosine MPI with regards to perfusion abnormalities, data are now available on the prognostic data derived from regadenoson MPI. We will briefly summarize these recent reports here in a focused update on the use of regadenoson for MPI.

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.

Safety and tolerability of regadenoson in 514 SPECT MPI patients with and without coronary artery disease and submaximal exercise heart rate response

PURPOSE

The safety of regadenoson (Reg) during low-level exercise testing has been established. However, its administration at peak exercise for patients who do not reach target heart rate (THR) on standard exercise treadmill stress testing (ETT) needs to be established, particularly among patients with known coronary artery disease (CAD) METHODS: From our stress myocardial perfusion imaging (MPI) database, we identified all patients between 2009 and 2012 who underwent standard ETT and received Reg at peak exercise for failure to reach THR. Hemodynamics, side effects, and adverse events were entered prospectively into the database at the time of testing and were subsequently retrieved for analysis.

RESULTS

There were 514 patients, mean age 60 ± 12 years, 34 % female gender, and 51 % with prior CAD. There were 218 (42 %) and 297 (57 %) patients who underwent standard or modified Bruce and Cornell protocols, respectively, and with a mean exercise time of 5.8 ± 2.1 min. The mean percentage of peak heart rate achieved was 71 ± 8 %, and mean maximal metabolic equivalent (MET) was 6.7 ± 1.8. There were 63 (12 %) patients who developed ≥30 mmHg drop in systolic blood pressure (SBP) after 2 min of Reg administration, and 10 (2 %) had SBP <100 mmHg at 2 min and were younger and achieved higher METs; 8 and 2 patients were symptomatic, respectively. The most common side effects reported were shortness of breath (12 %), chest pain/discomfort (13 %), and dizziness (7 %). There was one syncopal event, but no high-degree heart block, cardiac or respiratory arrest. Four patients received aminophylline. Women were more likely to have shortness of breath or gastrointestinal symptoms, while diabetics were less likely to have chest discomfort. There was otherwise no significant difference in adverse events between different groups including those with and without CAD.

CONCLUSION

Among patients undergoing standard treadmill stress testing for MPI who do not reach THR, the administration of Reg at peak exercise is safe and without major adverse events. Future large prospective studies are warranted to further evaluate the off-label use of Reg in this setting.

Selective adenosine agonists and myocardial perfusion imaging

Selective adenosine receptor agonists have several advantages for use as stress agents in conjunction with myocardial perfusion imaging compared to the non selective agents such as adenosine and dipyridamole. This review will summarize the pre-clinical and clinical data on the selective adenosine agonist stress agents regadenoson (Lexiscan(®)), binodenoson (CorVue™) and apadenoson (Stedivaze™) that have been studied so far with focus on regadenoson that has the most clinical data published so far. The article will review the adenosine receptor types and properties. It will also review the various attributes of the selective adenosine agonists including their pharmacology, pharmacokinetics and pharmacodynamics, their coronary vasodilatory and hemodynamic effects, their safety and side effects, their interactions with other drugs and their use with myocardial perfusion imaging. The landmark trials of the selective adenosine agonists will be reviewed as well as their use in special patient populations undergoing stress myocardial perfusion imaging.