Prevalence and disease features of myocardial ischemia with non-obstructive coronary arteries: Insights from a dynamic CT myocardial perfusion imaging study

https://doi.org/10.1016/j.ijcard.2021.04.055Get rights and content

Highlights

  • The overall prevalence of INOCA was low (6.4%) in patients with stable angina.

  • HRPs were less frequently presented in patients with INOCA.

  • Dynamic CT-MPI + CCTA was helpful for accurate “one-stop shop” imaging of INOCA.

Abstract

Background

Ischemia with non-obstructive coronary arteries (INOCA) is not uncommon in clinical practice. However, the incidence and imaging characteristics of INOCA on dynamic CT myocardial perfusion imaging (CT-MPI) remains unclear. We aimed to investigate the prevalence and disease features of INOCA as evaluated by dynamic CT-MPI + coronary CT angiography (CCTA).

Methods

Patients with suspected chronic coronary syndrome and intermediate-to-high pre-test probability of obstructive CAD (according to updated Diamond and Forrester Chest Pain Prediction Rule) were referred for dynamic CT-MPI + CCTA and retrospectively included. Various parameters, including myocardial blood flow (MBF) and high-risk plaque (HRP) features, were measured. INOCA was diagnosed if patients were revealed to have myocardial ischemia and absence of obstructive stenosis.

Results

314 patients were finally included. 20 patients (6.4%) were observed to have myocardial ischemia without obstructive stenosis. In addition, 138 patients (43.9%) had normal or near normal findings, 101 patients (32.2%) had obstructive stenosis without myocardial ischemia and 55 patients (17.5%) had obstructive stenosis with myocardial ischemia. Compared with patients with normal/near normal findings, patients with INOCA showed a higher prevalence of positive remodeling (40.0% vs. 17.4%, p = 0.04). In patients with obstructive stenosis, the mean age, calcium score and incidence of spotty calcification, positive remodeling as well as HRPs were significantly higher than those in patients with INOCA (p < 0.05 for all).

Conclusions

The overall prevalence of INOCA was low in patients with suspected chronic coronary syndrome. HRPs were less frequently presented in patients with INOCA, compared with patients having obstructive coronary stenosis.

Introduction

Obstructive coronary artery disease (CAD) is the major cause for angina pectoris and ischemic heart disease (IHD) [1]. Detection of hemodynamically significant coronary stenosis is of clinical importance to guide proper treatment strategy, such as optimal medical therapy or revascularization [2]. However, myocardial ischemia in the absence of obstructive coronary stenosis can also be encountered in clinical practice and known as ischemia with non-obstructive coronary arteries (INOCA) [3].

Similar to IHD caused by coronary stenosis, INOCA is not a benign entity and has been reported to be associated with unfavorable prognosis if misdiagnosed or not properly treated [[3], [4], [5]]. Precise evaluation of coronary anatomy as well as myocardial perfusion is fundamental for accurate diagnosis of INOCA [6]. CT myocardial perfusion imaging (CT-MPI) combined with coronary computed tomography angiography (CCTA) has been recognized as an ideal one-stop shop imaging modality and may be helpful for detection of INOCA [7]. Moreover, with the latest technical development, dynamic CT-MPI is able to quantitatively assess myocardial blood flow (MBF) at low radiation exposure [[8], [9], [10], [11], [12]]. We hypothesized that dynamic CT-MPI was not only useful for diagnosing INOCA but also could reflect the disease features, such as ischemic severity and presence of high-risk plaque (HRP), as well. Therefore, the current study aimed to investigate the prevalence and disease features of INOCA in patients with suspected chronic coronary syndrome as revealed by dynamic CT-MPI.

Section snippets

Patient population

The hospital ethics committee approved this retrospective study and informed consent was waived in all patients. Patients with suspected chronic coronary syndrome and intermediate to high pre-test probability of obstructive CAD (according to updated Diamond and Forrester Chest Pain Prediction Rule) were referred for dynamic CT-MPI + CCTA and retrospectively included. All image data of these patients were reviewed and included from two tertiary hospitals. The exclusion criteria were: 1) patients

Clinical characteristics

A total of 503 patients with dynamic CT-MPI + CCTA were retrospectively reviewed. One hundred and eighty-nine patients were excluded due to various reasons of exclusion (details shown in Online Supplement Fig. E2). Of these 189 patients, 12 patients were excluded due to uninterpretable image quality of CCTA, which was caused by breathing artifact (5 cases) or arrythmia related artifact (7 cases). Finally, a total of 314 patients were included in the analysis. Detailed demographic data are

Discussion

The major finding of the current study is that the overall prevalence of INOCA was low (6.4%) in patients with suspected chronic coronary syndrome and intermediate to high pre-test probability of obstructive CAD. In addition, HRPs were less frequently presented in patients with INOCA, compared with patients having obstructive coronary stenosis.

INOCA is primarily driven by the presence of microvascular dysfunction or coronary artery spasm, which are not uncommonly encountered in clinical

Disclosures

None.

Funding sources

This study is supported by Medical Guidance Scientific Research Support Project of Shanghai Science and Technology Commission (Grant No.: 19411965100), Shanghai Municipal Education Commission-Gaofeng Clinical Medicine Grant Support (Grant No.: 20161428).

Conflicts of interest

There are no conflicts of interest.

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      In a study of 314 patients with intermediate-to-high pretest probability of CAD who underwent coronary CTA and dynamic computed tomography (CT) myocardial perfusion imaging (CT-MPI) [29], INOCA patients showed a higher prevalence of positive remodeling on coronary CTA and dynamic CT-MPI compared to patients with normal/near-normal findings, whereas other high-risk plaque (HRP) features, i.e. spotty calcification, napkin-ring sign, and low-attenuation, did not differ between the two groups. Additionally, patients with obstructive CAD were more likely to have these HRP features than those with normal or near-normal findings and INOCA [29]. Similarly, the Combined Non-invasive Coronary Angiography and Myocardial Perfusion Imaging Using 320 Detector Computed Tomography (Core320) study with approximately 10% INOCA patients, as confirmed by coronary CTA/CT perfusion (8%) or ICA/SPECT (12%) [30] showed that patients with INOCA had more pronounced positive remodeling than those with non-obstructive CAD and no ischemia, as identified by CT perfusion.

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    Dr. Yi Xu and Dr. Lihua Yu contributed equally to this study.

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