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.

中文翻译：

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三维超声心动图区域心肌应变与心脏计算机断层扫描技术的融合，用于无痛评估胸痛患者冠状动脉狭窄对血流动力学的影响

背景

对胸痛患者，冠状动脉狭窄和局部缺血程度的综合评估至关重要。计算机断层扫描冠状动脉造影（CTCA）上的中级狭窄经常触发下游核应力测试。没有压力和/或辐射的替代方法可能会产生重要的影响。从超声心动图图像测量的心肌应变可用于检测亚临床功能障碍。作者最近测试了将三维（3D）超声心动图术产生的区域静息纵向应变与CTCA的冠状动脉融合的可行性，以确定狭窄的血液动力学意义。本研究的目的是针对公认的参考技术验证这种方法。

方法

前瞻性研究了接受CTCA治疗的78例胸痛患者，他们还接受了3D超声心动图和regadenoson应力计算机断层扫描。左心室纵向应变数据（TomTec）用于生成融合的3D显示并检测每个冠状动脉区域的静息应变异常（RSA）。解释了计算机断层扫描冠状动脉造影图像的存在和狭窄程度。创建了心内膜下X射线衰减的融合3D显示，以检测应力灌注缺陷（SPD）。在至少一根动脉狭窄> 25％的患者中，量化了血流储备分数（HeartFlow）。针对两种不同的联合参考对RSA作为显着狭窄的标志物进行了验证：狭窄>

结果

在没有狭窄的> 50％且无SPD的99条动脉中，被认为是正常的，有19条（19％）有RSA。相反，狭窄> 50％和SPD时，RSA的发病率要高得多（24个中的17个[71％]）。相对于参考标准品A，RSA的敏感性，特异性和准确性分别为0.71、0.81和0.79，相对于参考标准品B，其敏感性分别为0.83、0.81和0.82。

结论

CTCA和3D超声心动图衍生的静息心肌应变的融合提供了组合的显示，这可能对确定冠状动脉异常的血液动力学或功能影响有用，而无需进行额外的电离辐射或压力测试。