Fusion of Three-Dimensional Echocardiographic Regional Myocardial Strain with Cardiac Computed Tomography for Noninvasive Evaluation of the Hemodynamic Impact of Coronary Stenosis in Patients with Chest Pain

Abstract

Background Combined evaluation of coronary stenosis and the extent of ischemia is essential in patients with chest pain. Intermediate-grade stenosis on computed tomographic coronary angiography (CTCA) frequently triggers downstream nuclear stress testing. Alternative approaches without stress and/or radiation may have important implications. Myocardial strain measured from echocardiographic images can be used to detect subclinical dysfunction. The authors recently tested the feasibility of fusion of three-dimensional (3D) echocardiography–derived regional resting longitudinal strain with coronary arteries from CTCA to determine the hemodynamic significance of stenosis. The aim of the present study was to validate this approach against accepted reference techniques. Methods Seventy-eight patients with chest pain referred for CTCA who also underwent 3D echocardiography and regadenoson stress computed tomography were prospectively studied. Left ventricular longitudinal strain data (TomTec) were used to generate fused 3D displays and detect resting strain abnormalities (RSAs) in each coronary territory. Computed tomographic coronary angiographic images were interpreted for the presence and severity of stenosis. Fused 3D displays of subendocardial x-ray attenuation were created to detect stress perfusion defects (SPDs). In patients with stenosis >25% in at least one artery, fractional flow reserve was quantified (HeartFlow). RSA as a marker of significant stenosis was validated against two different combined references: stenosis >50% on CTCA and SPDs seen in the same territory (reference standard A) and fractional flow reserve < 0.80 and SPDs in the same territory (reference standard B). Results Of the 99 arteries with no stenosis >50% and no SPDs, considered as normal, 19 (19%) had RSAs. Conversely, with stenosis >50% and SPDs, RSAs were considerably more frequent (17 of 24 [71%]). The sensitivity, specificity, and accuracy of RSA were 0.71, 0.81, and 0.79, respectively, against reference standard A and 0.83, 0.81, and 0.82 against reference standard B. Conclusions Fusion of CTCA and 3D echocardiography–derived resting myocardial strain provides combined displays, which may be useful in determination of the hemodynamic or functional impact of coronary abnormalities, without additional ionizing radiation or stress testing.

Global Myocardial Work Is Superior to Global Longitudinal Strain to Predict Significant Coronary Artery Disease in Patients With Normal Left Ventricular Function and Wall Motion

“…Alternative approaches have been explored to enhance the ability of resting echocardiography to identify patients with CAD. Mor-Avi et al 11 tested the feasibility of fusing resting three-dimensional echocardiography-derived regional LV longitudinal strain with coronary arteries from cardiac computed tomography. This allowed assessment of the hemodynamic significance of coronary stenosis in patients with chest pain without performing stress testing.…”

“…4,5 Myocardial deformation imaging using two-dimensional (2D) speckle-tracking echocardiography (STE) is a valuable tool, providing comprehensive quantitative assessment of myocardial function beyond EF and qualitative assessment of RWMAs. [6][7][8][9][10][11] Previous studies have shown that peak systolic longitudinal strain is reduced in patients with significant CAD, even when resting LV wall motion and EF are preserved. 2 However, one of the main limitations of STE is load dependency, which can affect the diagnostic accuracy of myocardial function evaluation.…”

“…2 However, one of the main limitations of STE is load dependency, which can affect the diagnostic accuracy of myocardial function evaluation. 11,12 An increase in afterload has been shown to decrease strain, leading to misinterpretation of the true contractile function of the myocardium. [12][13][14][15][16][17][18] Myocardial work (MW) accounts for deformation as well as afterload through interpretation of strain in relation to dynamic noninvasive LV systolic pressure.…”

Hybrid anatomo-functional imaging of coronary artery disease: Beneficial irrespective of its core components

“…Recent developments in fusion technology have enabled physicians to perform hybrid anatomo-functional imaging with stress echocardiography or similar echocardiographic techniques and CTA. [32][33][34] Unfortunately, no study has yet reported on the incremental comparative accuracy of such hybrid imaging in comparison to invasive assessments, even if reports using CT-FFR as gold standard are already available. 35 Cardiac magnetic resonance has gained significant ground in the comprehensive anatomic and functional assessment of cardiovascular disease.…”

Regional myocardial strain analysis via 2D speckle tracking echocardiography: validation with sonomicrometry and correlation with regional blood flow in the presence of graded coronary stenoses and dobutamine stress

“…Global longitudinal strain has emerged as a dependable metric to support clinical decision-making, although it is limited by the fact that it is a unidirectional, generalized measure of function. The added ability to reliably measure regional strains in all cardiac strain directions is advantageous, especially in the evaluation of ischemic heart disease with regional dysfunction [4][5][6].…”