The Value of a Coronary Computed Tomography Angiography plus Stress Cardiac Magnetic Resonance Imaging Strategy for the Evaluation of Patients with Chronic Coronary Syndrome

Abstract

Background: Noninvasive imaging methods, either anatomical or functional tests, serve as essential instruments for the appropriate management of patients with established or suspected coronary artery disease (CAD). We sought to evaluate the safety and efficacy of a coronary computed tomography angiography (CCTA) plus stress cardiac magnetic resonance imaging (S-CMR) strategy in patients with chronic coronary syndrome (CCS). Methods: Patients with suspected CCS showing intermediate coronary plaques (stenosis 30-70%) at CCTA underwent S-CMR. Patients with a positive S-CMR were referred to invasive coronary angiography (ICA) plus instantaneous wave-free ratio (iFR), and myocardial revascularization if recommended. All patients received guideline-directed medical therapy (GDMT), including high-dose statins, regardless of myocardial revascularization. The primary endpoint was a composite of death from cardiovascular causes, non-fatal myocardial infarction, and unplanned revascularization. Results: According to the results of CCTA, 62 patients showing intermediate coronary plaques underwent S-CMR, which was positive for a myocardial perfusion deficit in n = 17 (27%) and negative in n = 45 (73%) patients. According to the results of ICA plus iFR, revascularization was performed in 13 patients. No differences in the primary endpoint between the positive and negative S-CMR groups were observed at 1 year (1 [5.9%] vs. 1 [2.2%], p = 0.485) and after a median of 33.4 months (2 [11.8%] vs. 3 [6.7%]; p = 0.605). Conclusions: Our study suggests that a CCTA plus S-CMR strategy is effective for the evaluation of patients with suspicion of CCS at low-intermediate risk, and it may help to refine the selection of patients with intermediate coronary plaques at CCTA needing coronary revascularization.

Keywords: chronic coronary syndrome; coronary computed tomography angiography; guideline-directed medical therapy; intermediate coronary plaques; revascularization; stress cardiac magnetic resonance imaging.

Figure 1

Flow diagram of study population. CABG, coronary artery bypass grafting; CCS, chronic coronary syndrome; CCTA, coronary computed tomography angiography; ICA, invasive coronary angiography; iFR, instantaneous wave-free ratio; PCI, percutaneous coronary intervention; pts, patients; S-CMR, stress cardiac magnetic resonance imaging.

Figure 2

A 65-year-old man was admitted to our department for exertional dyspnea with onset a few months earlier. Both the 12-lead ECG and 2D-echo evaluation did not show any alterations. Considering the low–intermediate risk profile of the patient, CCTA was performed, showing an intermediate plaque on the proximal right coronary artery (RCA) and on the middle circumflex artery (CA). To evaluate their functional significance, a pharmacological stress–rest perfusion and LGE cardiac MRI with regadenoson (0.4 mg IV bolus) were performed (1.5-T MRI system). The left ventricular (LV) short-axis orientation was used for breath hold perfusion imaging, with three sections placed in the basal, midventricular, and apical regions of the LV, using a phased-array surface coil as receiver. In the stress examination, a significant subendocardial perfusion deficit was observed in the basal and middle region of the inferior wall and septum, as well as in the middle posterior wall and postero-lateral papillary muscle. No perfusion deficit was observed in the rest examination. Ten minutes later, using inversion recovery sequences, no LGE was observed. Thus, the patient underwent staged coronary angioplasty with DES placed on the RCA and CA. The patient was discharged uneventful, being free from angina at 3-year follow-up. (A) Stress–rest myocardial perfusion MRI in a patient with intermediate plaques on the right and circumflex coronary arteries. The left column shows a short-axis view at the level of the mid-left ventricle during stress (regadenoson), whereas the right column shows a short-axis view at the level of the mid-left ventricle during rest. The red arrows point to a subendocardial perfusion deficit in the middle region of the inferior wall and septum, extending to the basal segment, and in the middle posterior wall and postero-lateral papillary muscle. (B) Absence of late gadolinium enhancement (LGE) at cardiac MRI in the myocardial segments, supplied by the right and circumflex coronary arteries. The left column shows a 4-chamber view, and the right column shows a 3-chamber view: no LGE was observed.

Figure 3

(A) Kaplan–Meier analysis of event-free survival from primary composite outcome after a median follow-up of 33.4 months, comparison between positive and negative S-CMR patients. (B) Kaplan–Meier analysis of event-free survival from primary composite outcome after a median follow-up of 33.4 months, comparison between patients with positive S-CMR plus presence of ischemic scar and patients with either negative S-CMR and/or absence of ischemic scar.