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

Trials and Tribulations of Assessing New Imaging Protocols: Combining Vasodilator Stress With Exercise

Among all patients referred for stress myocardial perfusion imaging (MPI), a substantial proportion in contemporary practice cannot exercise. Another group of patients are those who are thought to be able to achieve an adequate workload with treadmill (or bicycle) exercise but do not achieve at least 85% of maximum predicted heart rate without developing symptoms. There has been substantial interest and literature on the adjunctive use of vasodilator stress during the same visit to generate best-quality results for patients who do not exercise adequately. Current American Society of Nuclear Cardiology Guidelines recommend the possible use of vasodilator stress agents to supplement exercise in those patients who do not achieve target heart rate. However, optimal timing of administration is not clear. Herein, we summarize literature to date on the combination of vasodilator and exercise stress testing in light of the recently published Exercise to Regadenoson in Recovery Trial (EXERRT).

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 and prognostic value of regadenoson stress cardiovascular magnetic resonance imaging in heart transplant recipients

BACKGROUND

There is a critical need for non-invasive methods to detect coronary allograft vasculopathy and to risk stratify heart transplant recipients. Vasodilator stress testing using cardiovascular magnetic resonance imaging (CMR) is a promising technique for this purpose. We aimed to evaluate the safety and the prognostic value of regadenoson stress CMR in heart transplant recipients.

METHODS

To evaluate the safety, we assessed adverse effects in a retrospective matched cohort study of consecutive heart transplant recipients who underwent regadenoson stress CMR matched in a 2:1 ratio to age- and gender-matched non-heart transplant patients. To evaluate the prognostic value, we compared the outcomes of patients with abnormal vs. normal regadenoson stress CMRs using a composite endpoint of myocardial infarction, percutaneous intervention, cardiac hospitalization, retransplantation or death.

RESULTS

For the safety analysis, 234 regadenoson stress CMR studies were included - 78 performed in 57 heart transplant recipients and 156 performed in non-heart transplant patients. Those in heart transplant recipients were performed at a median of 2.74 years after transplantation. Thirty-four (44%) CMR studies were performed in the first two years after heart transplantation. There were no differences in the rates of adverse effects between heart transplant recipients and non-heart transplant patients. To study the prognostic value of regadenoson stress CMRs, 20 heart transplant recipients with abnormal regadenoson stress CMRs were compared to 37 with normal regadenoson stress CMRs. An abnormal regadenoson stress CMR was associated with a significantly higher incidence of the composite endpoint compared with a normal regadenoson stress CMR (3-year cumulative incidence estimates of 32.1% vs. 12.7%, p = 0.034).

CONCLUSIONS

Regadenoson stress CMR is safe and well tolerated in heart transplant recipients, with no incidence of sinus node dysfunction or high-degree atrioventricular block, including in the first two years after heart transplantation. An abnormal regadenoson stress CMR identifies heart transplant recipients at a higher risk for major adverse cardiovascular events.

The EXERRT trial: "EXErcise to Regadenoson in Recovery Trial": A phase 3b, open-label, parallel group, randomized, multicenter study to assess regadenoson administration following an inadequate exercise stress test as compared to regadenoson without exercise for myocardial perfusion imaging using a SPECT protocol

BACKGROUND

This study assessed the non-inferiority and safety of regadenoson administration during recovery from inadequate exercise compared with administration without exercise.

METHODS

Patients unable to achieve adequate exercise stress were randomized to regadenoson 0.4 mg either during recovery (Ex-Reg) or 1 hour after inadequate exercise (Regadenoson) (MPI1). All patients also underwent non-exercise regadenoson MPI 1-14 days later (MPI2). The number of segments with reversible perfusion defects (RPDs) detected using single photon emission computerized tomography imaging was categorized. The primary analysis evaluated the majority agreement rate between Ex-Reg and Regadenoson groups.

RESULTS

1,147 patients were randomized. The lower bound of the 95% confidence interval of the difference in agreement rates (-6%) was above the -7.5% non-inferiority margin, demonstrating non-inferiority of Ex-Reg to Regadenoson. Adverse events were numerically less with Ex-Reg (MPI1). In the Ex-Reg group, one patient developed an acute coronary syndrome and another had a myocardial infarction following regadenoson after exercise. Upon review, both had electrocardiographic changes consistent with ischemia prior to regadenoson.

CONCLUSIONS

Administering regadenoson during recovery from inadequate exercise results in comparable categorization of segments with RPDs and with careful monitoring appears to be well tolerated in patients without signs/symptoms of ischemia during exercise and recovery.

A useful and easy to develop combined stress test for myocardial perfusion imaging: Regadenoson and isometric exercise, preliminary results

BACKGROUND

Regadenoson, a selective A2a receptor agonist, is a vasodilator increasingly used in myocardial perfusion imaging. Adjunction of isometric exercise is a simple method that could improve side effect profile while providing better image quality.

METHODS

Patients undergoing SPECT MPI were prospectively enrolled in handgrip-Regadenoson (HG-Reg test, N = 20) and Regadenoson (Reg) stress test (N = 40). Investigator blinded to stress test analyzed clinical data and images.

RESULTS

Heart rate (HR) increase was statistically higher in the HG-Reg group (27 vs 22 bpm, P = .019). Decrease in SBP was less frequent in the HG-Reg group than in the Reg group (55% vs 85.5%, P = .005), there were less drops >10 mmHg (45% vs 77.7%, P = .012). During stress testing, fewer subjects reported at least one side effect in the HG-Reg compared to Reg group (70% vs 92.5%, P = .021). Images were more often classified as good in the HG-Reg group (75% vs 52.5% in the Reg group, P = .25).

CONCLUSIONS

Adjunction of handgrip exercise to Regadenoson administration is a well-tolerated and easy method, without loss of time. Furthermore, image quality seems to be better.

Adenosine triphosphate stress 99mTc-methoxyisobutylisonitrile gated myocardial perfusion imaging efficacy in diagnosing stent restenosis following coronary stent implantation

Coronary stent restenosis rate following implantation is considerably high. The adenosine stress gated myocardial perfusion imaging (G-MPI) method has been widely used in the diagnosis, risk stratification and prognosis evaluation of coronary heart disease; however, the high cost of adenosine limits its clinical application. The aim of the present study was to investigate the efficacy of adenosine triphosphate (ATP) stress ^99mTc-methoxyisobutylisonitrile (^99mTc-MIBI) G-MPI for diagnosis in-stent restenosis following coronary stent implantation. Data from 66 patients with typical angina pectoris symptoms who had undergone percutaneous coronary stent implantation >3 months prior to participation in the study were analyzed. All the patients underwent ATP stress ^99mTc-MIBI G-MPI and coronary artery angiography as the criterion diagnostic standard within 1 month. The sensitivity, specificity, and accuracy of ATP stress ^99mTc-MIBI G-MPI in the assessment of in-stent restenosis were calculated. In addition, Fisher's exact probability methods were used to compare differences between experimental groups. Among 66 patients with a total of 99 implanted coronary arterial branches, 39 patients (59%) with 45 coronary arteries (45%) presented in-stent restenosis. The diagnostic sensitivity, specificity, accuracy, positive predictive and negative predictive value of ATP stress ^99mTc-MIBI G-MPI for assessing stent restenosis in all patients were 85, 89, 86, 92 and 80%, respectively. Similarly, these values in patients with myocardial infarction were 79, 88, 83, 88 and 78%, respectively, while in patients without myocardial infarction the values were 90, 91, 90, 95 and 83%, respectively. Therefore, the diagnostic efficacy of ATP stress ^99mTc-MIBI G-MPI in patients without myocardial infarction was higher compared with those with myocardial infarction; however, no significant difference was observed between the two groups. Furthermore, the sensitivity, specificity and accuracy for diagnosing LAD stent restenosis were higher compared with LCX and RCA stent restenosis, but with no significant differences observed (P>0.05). The present results indicated that ATP stress ^99mTc-MIBI G-MPI had a high clinical application value for diagnosing in-stent restenosis following coronary stent implantation as a non-invasive examination tool, with the advantages of safety and low cost.

The role of pharmacological stress testing in women

Pharmacological stress is an alternative method to dynamic exercise that combined with noninvasive imaging allows the detection of flow-limiting coronary artery disease (CAD). It represents the stress procedure of choice in patients who cannot exercise appropriately. In women, pharmacological stress combined with myocardial perfusion scintigraphy (MPS) has demonstrated to be highly accurate for the detection of obstructive CAD and a valuable tool that helps separate patients at low cardiac risk from those with an adverse prognosis. Pharmacological stress with positron emission tomographic (PET) imaging is increasingly used in the investigation of suspected obstructive CAD; available evidence shows that the diagnostic profile and prognostic value of stress PET imaging is similar to that of stress MPS in women.

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.

Does risk for major adverse cardiac events in patients undergoing vasodilator stress with adjunctive exercise differ from patients undergoing either standard exercise or vasodilator stress with myocardial perfusion imaging?

BACKGROUND

In patients with functional limitations, the use of adjunctive exercise with vasodilator stress has advantages over vasodilator stress alone in single photon emission computed tomography myocardial perfusion imaging (MPI) for technical reasons and with regards to more effective cardiac risk stratification. Whether patients who undergo vasodilator with adjunctive exercise stress MPI possess clinical characteristics and cardiac risk that differs from those who undergo standard exercise or vasodilator stress MPI is unknown.

METHODS

Prospectively collected data on 19,367 consecutive patients referred for stress MPI to a tertiary care center (9,331 [48%] underwent exercise-only, 3,793 [20%] underwent vasodilator plus exercise, and 6,243 [32%] underwent vasodilator-only) were analyzed. Perfusion data were scored using the ASNC 17-segment with a summed stress score (SSS) < 4 = normal, 4-8 = mildly abnormal, and > 8 = moderate to severely abnormal. Patients were followed a mean of 1.96 ± 0.95 years. Demographics, clinical characteristics, and the occurrence of major adverse cardiac events (cardiac death or nonfatal myocardial infarction) were compared between the three stress modality groups.

RESULTS

Comparison of demographics and clinical characteristics revealed significant differences in gender, age, cardiac risk factors, and stress MPI between the three stress modality groups (P < .001). In follow-up, cardiac event-free survival of patients in the vasodilator plus exercise stress group was significantly higher than those in the vasodilator-only group but lower than those in the exercise-only group (P < .001). Annualized cardiac event rates of patients in the vasodilator plus exercise stress group were significantly lower than those in the vasodilator-only group for all three categories of the SSS (P < .001). After multivariable adjustment, with exercise-only as reference category, vasodilator plus exercise and vasodilator-only stress emerged as independent predictors (more likely occurrence) of cardiac death, while vasodilator-only stress emerged as an independent predictor (more likely occurrence) of cardiac death or nonfatal myocardial infarction. With vasodilator-only as the reference category, exercise-only and vasodilator plus exercise stress emerged as independent predictors (less likely occurrence) of cardiac death as well as of cardiac death or nonfatal myocardial infarction.

CONCLUSIONS

Patients undergoing vasodilator plus exercise stress MPI possess clinical characteristics and cardiac risk that differs significantly from those undergoing either standard exercise or vasodilator stress MPI and places them in a lower risk category compared to vasodilator stress alone.

[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.

Comparative study of the safety of regadenoson between patients with mild/moderate chronic obstructive pulmonary disease and asthma

PURPOSE

To compare the safety of regadenoson, a selective agonist of A2A adenosine receptors, combined with low-level exercise, between subjects with mild/moderate chronic obstructive pulmonary disease (COPD) and asthma referred for myocardial perfusion imaging (MPI).

METHODS

We studied 116 patients, of whom 67 had COPD and 49 asthma (62 % men, mean age 68.3 ± 11.3 years, range 31 - 87 years). Patient demographics, past medical history, medications, clinical symptoms during stress and changes in blood pressure (BP) and heart rate (HR) were evaluated.

RESULTS

Both groups were comparable with regard to hypertension, dyslipidaemia, diabetes and medications with the exception of a higher rate of use of anticholinergics in patients with COPD and of antileukotrienes in asthmatics (58.2 % vs. 28.6 % and 1.5 % vs. 14.3 %, respectively; all p < 0.01). There was a higher incidence of dyspnoea in COPD patients and of headache and feeling hot in asthmatic patients (40.3 % vs. 22.4 %, 6 % vs. 18.4 % and 10.4 % vs. 26.5 %, respectively; all p < 0.05). Although there was no difference in the incidence of other adverse events, we observed a higher frequency in asthmatics of flushing, dry mouth, sweating and fatigue (1.5 % vs. 6.1 %, 14.9 % vs. 24.5 %, 0 % vs. 4.1 % and 37.3 % vs. 49 %, respectively). Adverse events were self-limiting, except in three patients who suffered persistent dyspnoea (2 of 67 COPD patients; 1 of 49 asthma patients) requiring theophylline administration. We observed no significant changes in BP among either group, but there was a tendency towards a higher increase in systolic BP in COPD patients following regadenoson administration (148.3 ± 27.6 vs. 154.6 ± 31.0 mmHg, p = 0.056).

CONCLUSION

This study showed a good safety profile in our series of COPD and asthma patients undergoing MPI. Regadenoson was well tolerated by all patients, with dyspnoea, headache and feeling hot showing differences between groups.