Asystole following regadenoson infusion in stable outpatients

Advanced Heart Block and Asystole After Regadenoson Infusion: When Cautionary Tales Become Reality

Regadenoson (brand name Lexiscan) is a specific adenosine receptor agonist commonly used in pharmacologic stress testing due to its coronary vasodilatory effects. Despite it being generally well-tolerated, the American Society of Nuclear Cardiology established absolute and relative contraindications to the use of regadenoson in patients with certain co-morbidities such as uncontrolled hyper/hypotension, sinus node disease, and second-degree heart blocks. While cases of advanced heart block after the administration of regadenoson have been reported, they remain incidental. We report the case of an 84-year-old male sustaining second-degree type II heart block, followed by pulseless electrical activity and asystole after the administration of regadenoson.

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.

Selective Adenosine A2A Agonists May Change Myocardial Perfusion Imaging

In recent years, the requirement for pharmacological stress myocardial perfusion imaging (SPECT) has increased, and adenosine stress testing is now the mainstream. Selective adenosine A2A receptor agonists will be applied clinically in the future. By selectively activating only A2A receptors, it can reduce complications such as bronchospasm, hypotension, and bradycardia, which have been problems with adenosine stress tests. In addition, since this drug can be administered in bolus injection, it has the advantage of being able to perform the test at one root.

Regadenoson administration and QT interval prolongation during pharmacological radionuclide myocardial perfusion imaging

The objective of our study is to assess change in QTc interval with Regadenoson administration during myocardial perfusion imaging (MPI). We conducted a retrospective, observational analysis of 1497 consecutive patients who underwent pharmacological radionuclide MPI. On multivariate logistic regression analyses, there was no statistical significance of QTc prolongation when adjusted for ischemia/fixed perfusion defect on MPI and QT prolonging medications being taken prior to stress testing. However, a positive stress ECG after Regadenoson injection had a statistical significance (p value 0.0004). Regadenoson is a safe drug for use in MPI with little, if any, side effects of major clinical significance.

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.

Safety of vasodilator stress myocardial perfusion imaging in patients with elevated cardiac biomarkers

BACKGROUND

While adenosine and dipyridamole as myocardial perfusion imaging (MPI) stress agents have literature supporting their safety in the setting of myocardial infarction (MI), regadenoson does not. Studying a high risk cohort of patients with elevated cardiac biomarkers may shed light on potential safety issues of these agents which might also affect lower risk cohorts.

METHODS

All patients who had undergone a clinically indicated stress MPI study at two academic centers from 1/1/2010 through 12/31/2012 with elevated troponin ≤7 days prior to testing were included. The primary endpoint was a composite of death, non-fatal MI, congestive heart failure (CHF), stroke, ventricular arrhythmias, atrial fibrillation/flutter, or atrioventricular block requiring intervention within 24 h of testing.

RESULTS

Of the 703 stress MPI studies that met inclusion criteria, 360 (51.2%), 199 (28.3%), 74 (10.5%), 9 (1.3%), and 61 (8.7%) underwent regadenoson, dipyridamole, adenosine, dobutamine, and exercise stress, respectively. The primary endpoint occurred in 11 (1.6%) patients with an incidence of 1.4% (n = 5), 1.0% (n = 2), 1.4% (n = 1), 11.1% (n = 1), and 3.3% (n = 2) following regadenoson, dipyridamole, adenosine, dobutamine, and exercise stress, respectively (P = 0.137). The adverse events included non-fatal MI in 7 (1.0%) patients, death in 1 (0.1%) patient, CHF in 1 (0.1%) patient, ventricular arrhythmia in 1 (0.1%) patient, and atrial arrhythmia in 1 (0.1%) patient.

CONCLUSION

In the setting of elevated troponin, serious complications associated with either exercise or vasodilator stress testing appear to be relatively rare with no increased risk attributable to a particular vasodilator agent.

Non-invasive assessment of low- and intermediate-risk patients with chest pain

Coronary artery disease (CAD) remains a significant global public health burden despite advancements in prevention and therapeutic strategies. Common non-invasive imaging modalities, anatomic and functional, are available for the assessment of patients with stable chest pain. Exercise electrocardiography is a long-standing method for evaluation for CAD and remains the initial test for the majority of patients who can exercise adequately with a baseline interpretable electrocardiogram. The addition of cardiac imaging to exercise testing provides incremental benefit for accurate diagnosis for CAD and is particularly useful in patients who are unable to exercise adequately and/or have uninterpretable electrocardiograms. Radionuclide myocardial perfusion imaging and echocardiography with exercise or pharmacological stress provide high sensitivity and specificity in the detection and further risk stratification of patients with CAD. Recently, coronary computed tomography angiography has demonstrated its growing role to rule out significant CAD given its high negative predictive value. Although less available, stress cardiac magnetic resonance provides a comprehensive assessment of cardiac structure and function and provides a high diagnostic accuracy in the detection of CAD. The utilization of non-invasive testing is complex due to various advantages and limitations, particularly in the assessment of low- and intermediate-risk patients with chest pain, where no single study is suitable for all patients. This review will describe currently available non-invasive modalities, along with current evidence-based guidelines and appropriate use criteria in the assessment of low- and intermediate-risk patients with suspected, stable CAD.

Safety and tolerability of regadenoson for myocardial perfusion imaging - first Danish experience

OBJECTIVES

Evaluating safety and tolerability of the selective A2A receptor agonist, regadenoson, in patients referred for single photon emission computed tomography myocardial perfusion imaging (MPI).

DESIGN

Observational study of patients referred for MPI stress testing using a 400 μg regadenoson (Rapiscan(®)) bolus. Hemodynamic variables and severity of adverse events (AE) were recorded before, during, and after administration.

RESULTS

A total of 232 patients were included. One or more AE were reported in 90% of patients; the AEs were graded mostly mild to moderate in severity, resolved spontaneously, and were mainly dyspnea, headache, and chest pain. No advanced heart block or bronchospasm were seen. Transient ST-segment changes developed in 10 patients. The maximum increase in heart rate was 19 ± 11 beats/minute. The mean systolic blood pressure decreased from 144 to 139 mmHg (p < 0.0001). Medical intervention was required in three patients: one case with severe hypotension and two cases with chest pain that was relieved with sublingual nitroglycerin. One patient died the day after stress MPI for reasons considered unrelated to regadenoson.

CONCLUSION

Regadenoson for MPI is easy to use with a high frequency of AEs, which are generally mild in severity, transient, and resolve spontaneously.

Review of cardiovascular imaging in The Journal of Nuclear Cardiology in 2014: Part 2 of 2: Myocardial perfusion imaging

In this new feature of The Journal of Nuclear Cardiology we will summarize key articles that were published in the Journal in the previous year. In the first article of this 2-part series we concentrated on publications dealing with cardiac positron emission tomography, computed tomography, and neuronal imaging. This review will focus on myocardial perfusion imaging summarizing advances in the field including in diagnosis, prognosis, appropriateness, and safety of testing.

Regadenoson provides perfusion results comparable to adenosine in heterogeneous patient populations: a quantitative analysis from the ADVANCE MPI trials

BACKGROUND

Total and reversible left ventricular (LV) perfusion defect size (PDS) predict patient outcome. Limited data exist as to whether regadenoson induces similar perfusion abnormalities as observed with adenosine. We sought to determine whether regadenoson induces a similar LV PDS as seen with adenosine across varying patient populations.

METHODS AND RESULTS

ADVANCE MPI were prospective, double-blind randomized trials comparing regadenoson to standard adenosine myocardial perfusion tomography (SPECT). Following an initial adenosine SPECT, patients were randomized to either regadenoson (N = 1284) or a second adenosine study (N = 660). SPECT quantification was performed blinded to randomization and image sequence. Propensity analysis was used to define comparability of regadenoson and adenosine perfusion results. Baseline clinical and SPECT results were similar in the two randomized groups. There was a close correlation between adenosine and regadenoson-induced total (r (2) = 0.98, P < .001) and reversible (r (2) = 0.92, P < .001) PDS. Serial differences in total (0.00 ± 3.51 vs -0.11 ± 3.46, P = .51) and reversible (0.15 ± 3.79 vs 0.07 ± 3.33, P = .65) PDS were also comparable in patients randomized to regadenoson vs adenosine, respectively, and irrespective of age, gender, diabetic status, body mass index, or prior cardiovascular history. By propensity analysis, regadenoson-induced total PDS was significantly larger than observed with adenosine.

CONCLUSION

This is the first study to show that regadenoson induces similar, if not larger, perfusion defects than those observed with adenosine across different patient populations and demonstrates the value of quantitative analysis for defining serial changes in SPECT perfusion results. Regadenoson should provide comparable diagnostic and prognostic SPECT information to that obtained with adenosine.