Original ArticleThe diagnostic and prognostic value of near-normal perfusion or borderline ischemia on stress myocardial perfusion imaging
Introduction
Stress myocardial perfusion imaging (MPI) with single-photon emission computed tomography (SPECT) is among the most commonly used methods in the assessment and risk stratification of patients with known or suspected coronary artery disease (CAD).1,2 The prognostic value of SPECT-MPI has been extensively studied, and data indicate that an abnormal scan is associated with a multi-fold increase in the risk of major adverse cardiac events (MACE).3,4 Conventionally, a SPECT-MPI scan with a summed stress score (SSS) ≥ 4 is defined as abnormal and a summed difference score (SDS) ≥ 2 is considered to represent myocardial ischemia.5, 6, 7, 8 While an SSS and SDS of 0 represent a “completely” normal perfusion, less than “perfectly normal” scans with SSS of 1-3 or SDS of 1 are considered within normal limits.5,6 Regadenoson, a selective A2A adenosine receptor agonist, is the most commonly used stress agent with SPECT-MPI in the U.S., owing to its favorable safety and tolerability profile.9, 10, 11 The prognostic value of abnormal regadenoson MPI has been previously evaluated,4,8,12,13 but data on the significance of near-normal MPI (SSS = 1-3) or borderline ischemia (SDS = 1), with otherwise normal scan, are lacking. In this study, we aimed at investigating the prognostic value of near-normal MPI and borderline myocardial ischemia in patients undergoing regadenoson SPECT-MPI.
Section snippets
Design and patient population
We implemented a retrospective cohort study design. This investigation was a sub-analysis of the database generated from a previously published investigation assessing the prognostic significance of regadenoson induced ST-segment changes. Data from this cohort have been published elsewhere.4,14,15 Cardiology information system at Rush University Medical Center was queried for all patients who underwent a clinically indicated regadenoson-stress SPECT-MPI during the period from July 1, 2009
Results
Among the 6,802 patients included in the analysis, 4,398 had normal MPI (SSS = 0) and 2,404 had near-normal scan (SSS = 1-3). Baseline characteristics of study subjects are summarized in Table 1. Notably, the mean age was 61.9 ± 13.4 years and the majority were women (58.1%). Patients with near-normal MPI had significantly more comorbid conditions and higher mean BMI when compared to those with normal scan. The mean TID was similar between the two groups. Within the study cohort, 6,229 patients
Discussion
This is one of the largest studies to evaluate the diagnostic and prognostic value of near-normal MPI or borderline ischemia in otherwise normal MPI. We demonstrated that patients with near-normal MPI (SSS = 1-3) and borderline ischemia (SDS = 1) were more likely to be referred for invasive coronary angiography within 6 month of the index MPI and they had higher rates of obstructive CAD. We also demonstrated that near-normal MPI is associated with increased risk of CR, while borderline
Limitations
Our investigation has several limitations. First, the study is inherently limited by the retrospective, single-center design. Second, the study was limited to patients undergoing regadenoson vasodilator stress, which may limit its generalizability to patients undergoing exercise stress MPI. Third, the cause of death in some patients was determined using death certificates which are not always accurate. In addition, death certificates issued outside the state of Illinois could not be obtained,
New knowledge gained
In this study, we demonstrated that near-normal MPI and borderline ischemia, in otherwise normal scan, are associated with higher prevalence of obstructive CAD and a statistically significant increase of CR compared to “completely” normal MPI. Borderline ischemia was even associated with severe/extensive CAD and increased risk of LCR. It is reassuring, however, that subtle perfusion abnormalities were not associated with a significant difference in the risk of the primary “hard” endpoint of
Conclusions
Near-normal SPECT-MPI and borderline ischemia, in otherwise normal scan, are associated with higher prevalence of obstructive CAD and increased risk of coronary revascularizations. Discriminating near-normal MPI or borderline ischemia from a perfectly normal scan can further refine identification of obstructive CAD and risk stratification. Close clinical surveillance, aggressive medical management, and additional imaging evaluation may be considered in these patients.
Funding
The study was partially funded by Astellas Pharma Global Development (Northbrook, IL).
Disclosure
No personal conflicts of interest to be reported by any of the authors.
References (29)
- et al.
The prognostic value of regadenoson myocardial perfusion imaging
J Nucl Cardiol
(2015) - et al.
Single photon emission computed tomography (SPECT) myocardial perfusion imaging guidelines: Instrumentation, acquisition, processing, and interpretation
J Nucl Cardiol
(2018) - et al.
ASNC imaging guidelines for nuclear cardiology procedures: Standardized reporting of nuclear cardiology procedures
J Nucl Cardiol
(2017) - et al.
Diagnostic and prognostic significance of ischemic electrocardiographic changes with regadenoson-stress myocardial perfusion imaging
J Nucl Cardiol
(2015) - et al.
Attenuation of the side effect profile of regadenoson: A randomized double-blinded placebo-controlled study with aminophylline in patients undergoing myocardial perfusion imaging. “The ASSUAGE trial”
J Nucl Cardiol
(2012) - et al.
The safety and tolerability of regadenoson in patients with end-stage renal disease: The first prospective evaluation
J Nucl Cardiol
(2013) - et al.
The prognostic value of regadenoson SPECT myocardial perfusion imaging in patients with end-stage renal disease
J Nucl Cardiol
(2017) - et al.
Soft tissue attenuation patterns in stress myocardial perfusion SPECT images: A comparison between supine and upright acquisition systems
J Nucl Cardiol
(2011) - et al.
The impact of regimented aminophylline use on extracardiac radioisotope activity in patients undergoing regadenoson stress SPECT myocardial perfusion imaging: A substudy of the ASSUAGE trial
J Nucl Cardiol
(2014) - et al.
The prognostic value of transient ischemic dilatation with otherwise normal SPECT myocardial perfusion imaging: A cautionary note in patients with diabetes and coronary artery disease
J Nucl Cardiol
(2013)
The significance of automatically measured transient ischemic dilation in identifying severe and extensive coronary artery disease in regadenoson, single-isotope technetium-99m myocardial perfusion SPECT
J Nucl Cardiol
The significance of post-stress decrease in left ventricular ejection fraction in patients undergoing regadenoson stress gated SPECT myocardial perfusion imaging
J Nucl Cardiol
The prognostic value of normal exercise myocardial perfusion imaging and exercise echocardiography: A meta-analysis
J Am Coll Cardiol
Current worldwide nuclear cardiology practices and radiation exposure: Results from the 65 country IAEA Nuclear Cardiology Protocols Cross-Sectional Study (INCAPS)
Eur Heart J
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All editorial decisions for this article, including selection of reviewers and the final decision, were made by guest editor Randall Thompson, MD.