Coronary Artery Disease
Comparison of Myocardial Transmural Perfusion Gradient by Magnetic Resonance Imaging to Fractional Flow Reserve in Patients With Suspected Coronary Artery Disease

https://doi.org/10.1016/j.amjcard.2015.02.039Get rights and content

The goal of this study was to evaluate the diagnostic accuracy of transmural perfusion gradient (TPG) and transmural perfusion gradient reserve (TPGR) with 3.0 T cardiac magnetic resonance (CMR) against invasively determined fractional flow reserve (FFR) to detect coronary artery stenosis. Quantitative analysis of myocardial perfusion with CMR to diagnosis coronary artery disease (CAD) has been widely accepted. However, traditional transmural myocardial perfusion analysis with CMR neglects that endocardium is more vulnerable to ischemia than epicardium. TPG and TPGR can take the inhomogenous perfusion impairment into account and be more sensitive and specific for diagnosis of CAD. In this study, 71 patients (57 men, age 60.1 ± 6.4 years) with known or suspected CAD referred for invasive angiography study underwent rest and adenosine-induced stress CMR perfusion imaging scan. FFR was attempted to be measured in all major epicardial coronary arteries. FFR ≤0.75 was regarded to indicate a hemodynamic significant coronary lesion. A TPG ≤0.85 predicted significant CAD with sensitivity and specificity of 74.55% and 83.65%, respectively. Sensitivity and specificity of TPGR ≤0.81 were 90.91% and 89.94%, respectively. Area under the receiver-operating curve to detect FFR ≤0.75 was 0.86 for TPG and 0.95 for TPGR. TPGR yielded significantly better sensitivity and specificity for diagnosis of CAD than traditional myocardial blood flow, myocardial perfusion reserve, and TPG (p <0.0001). In conclusion, TPG and TPGR analyses with MRI are capable of detecting hemodynamic stenosis of coronary artery and superior to traditional myocardial perfusion analysis. Furthermore, TPGR appears to be superior to TPG in the diagnosis of coronary artery stenosis.

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Methods

Patients with suspected or known CAD referred for coronary angiography and FFR measurement were prospectively recruited and underwent CMR perfusion imaging before invasive coronary studies. Exclusion criteria included previous ST-segment elevation infarction, acute coronary syndrome <6 weeks, previous coronary artery bypass graft, impaired left ventricular (LV) function (ejection fraction <40%), estimated glomerular filtration rate <30 ml/min, contraindication to adenosine or gadolinium (Gd)

Results

Of the 76 patients recruited to the study, 5 patients were excluded (1 had claustrophobia, 2 refused to undergo FFR measurement, and 2 with aborted FFR procedure because of vasospasm). The study protocol was completed in 71 patients. Patient demographics are provided in Table 1. A total of 213 coronary arteries were available for analysis. Hemodynamic status changes after adenosine stress both in CMR acquisition and FFR procedure are listed in Table 2. Stressing heart rate was significantly

Discussion

Our study was based on quantitative CMR analysis of myocardial perfusion, and we found that (1) TPG and TPGR with CMR are better than conventional transmural perfusion analysis to detect hemodynamically significant coronary artery stenosis determined by FFR and (2) diagnostic sensitivity of TPGR seems to be superior to TPG with CMR.

Adenosine stress perfusion CMR has been proved to be a useful diagnostic tool in suspected patients with CAD. Quantitative perfusion analysis, such as MBF and MPR,

Disclosures

The authors have no conflicts of interest to disclose.

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    Drs. Pan and Huang contributed equally to this work.

    See page 1339 for disclosure information.

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