Original Article
Assessment of the relationship between stenosis severity and distribution of coronary artery stenoses on multislice computed tomographic angiography and myocardial ischemia detected by single photon emission computed tomography

https://doi.org/10.1007/s12350-010-9230-6Get rights and content

Abstract

Background

The relationship between luminal stenosis measured by coronary CT angiography (CCTA) and severity of stress-induced ischemia seen on single photon emission computed tomographic myocardial perfusion imaging (SPECT-MPI) is not clearly defined. We sought to evaluate the relationship between stenosis severity assessed by CCTA and ischemia on SPECT-MPI.

Methods and Results

ECG-gated CCTA (64 slice dual source CT) and SPECT-MPI were performed within 6 months in 292 patients (ages 26-91, 73% male) with no prior history of coronary artery disease. Maximal coronary luminal narrowing, graded as 0, ≥25%, 50%, 70%, or 90% visual diameter reduction, was consensually assessed by two expert readers. Perfusion defect on SPECT-MPI was assessed by computer-assisted visual interpretation by an expert reader using the standard 17 segment, 5 point-scoring model (stress perfusion defect of ≥5% = abnormal). By SPECT-MPI, abnormal perfusion was seen in 46/292 patients. With increasing stenosis severity, positive predictive value (PPV) increased (42%, 51%, and 74%, P = .01) and negative predictive value was relatively unchanged (97%, 95%, and 91%) in detecting perfusion abnormalities on SPECT-MPI. In a receiver operator curve analysis, stenosis of 50% and 70% were equally effective in differentiating between the presence and absence of ischemia. In a multivariate analysis that included stenosis severity, multivessel disease, plaque composition, and presence of serial stenoses in a coronary artery, the strongest predictors of ischemia were stenosis of 50-89%, odds ratio (OR) 7.31, P = .001, stenosis ≥90%, OR 34.05, P = .0001, and serial stenosis ≥50% OR of 3.55, P = .006.

Conclusions

The PPV of CCTA for ischemia by SPECT-MPI rises as stenosis severity increases. Luminal stenosis ≥90% on CCTA strongly predicts ischemia, while <50% stenosis strongly predicts the absence of ischemia. Serial stenosis of ≥50% in a vessel may offer incremental value in addition to stenosis severity in predicting ischemia.

Introduction

Coronary CT angiography (CCTA) provides excellent anatomic assessment of the extent and severity of coronary artery disease (CAD), with high diagnostic accuracy for detection of significant stenosis in patients who present with symptoms suggestive of ischemia.1, 2, 3, 4 With its high negative predictive value, CCTA has become useful for exclusion of CAD in patients with chest pain syndromes. However, the clinical management of a patient with an abnormal CCTA is not well defined. Single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is an accepted standard for detection and quantification of significant myocardial ischemia and has been shown to be a strong prognostic indicator of the risk for adverse cardiac events.5,6 The increasing use of CCTA for diagnosis of CAD has led to several studies comparing stenosis severity on CCTA to ischemia on SPECT-MPI7, 8, 9, 10, 11 and PET.12 However, these reports have been limited by modest-sized, heterogeneous populations that often included patients known to have CAD. Furthermore, previous studies have not addressed the relationship between CCTA-based assessment of plaque characteristics and ischemia by SPECT-MPI. In this study, we compared CCTA-based assessment of stenosis severity to SPECT-MPI in a large cohort of consecutive patients with no previous history of CAD. Our objectives were to determine whether there is a degree of luminal stenosis on CCTA above which myocardial ischemia on SPECT-MPI is highly likely, to determine the degree of stenosis severity below which abnormal SPECT-MPI is so unlikely that further diagnostic testing would not be required, and to explore whether the distribution of significant stenoses in the vessel can improve prediction of myocardial ischemia.

Section snippets

Patients and Study Protocol

We studied 294 consecutive patients without known CAD—defined by history of myocardial infarction, coronary revascularization, or presence of angiographically documented coronary stenoses of ≥50% luminal diameter by invasive coronary angiography—participating in the Cedars-Sinai Cardiac Imaging Database Registry and undergoing both CCTA and SPECT-MPI for suspected ischemic heart disease at Cedars-Sinai Medical Center within 6 months. These patients did not experience change in symptoms or

Patient Characteristics

Of the 292 patients, 192 were men (66%, see Table 1). The median age was 62 years (range, 26-91), and the median pretest likelihood of CAD (before the first test) was 58% (range, 2-96%). Seventy percent (n = 203) of patients had chest discomfort or shortness of breath before the first test that persisted at the time of the second test. The remaining 30% (n = 89) had either equivocal or abnormal results on the first test (n = 43), or discordant results (e.g., abnormal stress ECG, normal

Discussion

In this head-to-head comparison of stenosis severity assessment by CCTA and myocardial perfusion by SPECT-MPI, we observe the following key findings. One, there is a direct relationship between luminal stenosis severity measured by CCTA and the prevalence of ischemia measured by SPECT-MPI. Two, at the extremes of luminal stenosis severity, <50% (NPV of 98%) or ≥90% (PPV of 74%), CCTA capably predicts the absence or presence of ischemia. On the other hand, there is wide variability in the

Limitations

Our studies were a retrospective analysis of patients who had undergone SPECT-MPI and CCTA within 6 months. Although this is a fairly long duration between studies, the median duration between studies was 4 days and 75% of patients underwent both studies within 2 weeks. Moreover, patients considered for analysis did not have a change in clinical status between the studies. Our study included a significant number of patients with low pretest likelihood of CAD and this may be reflected in the

Conclusions

The presence of ischemia increases in proportion to the severity of luminal stenosis and the PPV of ischemia measured by SPECT-MPI rises as stenosis severity increases. A luminal stenosis of ≥90% by CCTA is a strong predictor of ischemia on SPECT-MPI. Individuals with luminal stenosis of <50% are so unlikely to have myocardial ischemia that such patients may generally not need ischemia testing. In the group of individuals with luminal stenosis of ≥50%, the presence of serial luminal stenoses of

References (38)

  • AgatstonAS et al.

    Quantification of coronary artery calcium using ultrafast computed tomography

    J Am Coll Cardiol

    (1990)
  • BermanDS et al.

    Prognostic validation of a 17-segment score derived from a 20-segment score for myocardial perfusion SPECT interpretation

    J Nucl Cardiol

    (2004)
  • BermanDS et al.

    Adenosine myocardial perfusion single-photon emission computed tomography in women compared with men. Impact of diabetes mellitus on incremental prognostic value and effect on patient management

    J Am Coll Cardiol

    (2003)
  • SlomkaPJ et al.

    Automated quantification of myocardial perfusion SPECT using simplified normal limits

    J Nucl Cardiol

    (2005)
  • BermanDS et al.

    Quantitative assessment of myocardial perfusion abnormality on SPECT myocardial perfusion imaging is more reproducible than expert visual analysis

    J Nucl Cardiol

    (2009)
  • HoffmannU et al.

    Noninvasive assessment of plaque morphology and composition in culprit and stable lesions in acute coronary syndrome and stable lesions in stable angina by multidetector computed tomography

    J Am Coll Cardiol

    (2006)
  • LeberAW et al.

    Quantification of obstructive and nonobstructive coronary lesions by 64-slice computed tomography: A comparative study with quantitative coronary angiography and intravascular ultrasound

    J Am Coll Cardiol

    (2005)
  • LeberAW et al.

    Composition of coronary atherosclerotic plaques in patients with acute myocardial infarction and stable angina pectoris determined by contrast-enhanced multislice computed tomography

    Am J Cardiol

    (2003)
  • LinFY et al.

    Relation of plaque characteristics defined by coronary computed tomographic angiography to ST-segment depression and impaired functional capacity during exercise treadmill testing in patients suspected of having coronary heart disease

    Am J Cardiol

    (2009)

    • Cited by (40)

    • Cardiac Computed Tomography

      2017, Practical Cardiology

    • CACS and the Frequency of Stress-Induced Myocardial Ischemia during MPI A Meta-Analysis

      2016, JACC: Cardiovascular Imaging

    • Coronary computed tomography angiography alone versus confirmatory functional testing for guiding treatment strategy for patients with intermediate coronary artery stenosis

      2015, American Journal of Cardiology

    • Regadenoson dynamic computed tomography myocardial perfusion using low-dose protocol for evaluation of the ischemic burden. ULYSSES study

      2020, Journal of Cardiovascular Computed Tomography

    • Elevated Native T1 Values in the Remote Myocardium Supplied by Obstructive Non-Infarct Related Coronary Arteries in Post-STEMI Cardiac Magnetic Resonance

      2023, Cardiology (Switzerland)

    • Atlas of Hybrid Imaging: Volume 3: Sectional Anatomy for PET/ CT, PET/ MRI and SPECT/ CT: Heart, Lymph Node and Musculoskeletal System

      2023, Atlas of Hybrid Imaging: Volume 3: Sectional Anatomy for PET/ CT, PET/ MRI and SPECT/ CT: Heart, Lymph Node and Musculoskeletal System
    View all citing articles on Scopus

    Balaji K. Tamarappoo and Ariel Gutstein contributed equally to this work.

    The study was supported in part by grants from the Lincy Foundation and Diane and Gilford Glazer.

    View full text
    Copyright © 2010 THE AUTHORS. Published by ELSEVIER INC. on behalf of American Society of Nuclear Cardiology. Published by Mosby, Inc. All rights reserved.