Jeremy D. Rier

Diagnostic value of quantitative stenosis predictors with coronary CT angiography compared to invasive fractional flow reserve

OBJECTIVE To evaluate the diagnostic performance of CCTA-derived stenosis predictors including CT-FFR for the detection of ischemia-inducing stenosis compared to invasive FFR. MATERIALS AND METHODS Stenosis parameters were assessed using dual-source CT (DSCT). All patients underwent both CCTA and invasive FFR within 3 months and were retrospectively analyzed. Observers visually assessed all CCTA studies and performed multiple lesion measurements. Lesion length/minimal luminal diameter(4) (LL/MLD(4)), transluminal attenuation gradient (TAG), corrected coronary attenuation (CCO) and CT-FFR were calculated. RESULTS The cohort included 32 patients (58±12 years, 66%male). Among 32 coronary lesions, 8 (25%) were considered hemodynamically significant with an FFR <0.80. Compared to invasive FFR, the per-vessel sensitivity and specificity of CCTA, CT-FFR, LL/MLD(4), CCO and TAG for detecting hemodynamically significant lesions were 100% and 54%, 100% and 91%, 85% and 92%, 66% and 88%, 37% and 58%, respectively. Receiver operating characteristics analysis resulted in an area under the curve of 0.91 for CT-FFR (p=0.0005), 0.88 for LL/MLD(4) (p<0.0001), 0.85 for CCO (p<0.0001). TAG with an AUC of 0.67 (p=0.152) was unable to discriminate between vessels with or without hemodynamically significant lesions. CONCLUSION CT-FFR, LL/MLD(4) and CCO provide enhanced diagnostic performance over CCTA analysis alone for discrimination of hemodynamically significant coronary stenosis.

Comparison of quantitative stenosis characteristics at routine coronary computed tomography angiography with invasive fractional flow reserve for assessing lesion-specific ischemia

OBJECTIVE To comprehensively evaluate quantitative parameters derived from routine coronary CT angiography (cCTA) for predicting lesion-specific ischemia in comparison to invasive fractional flow reserve (FFR). BACKGROUND The ability of cCTA to gauge lesion-specific ischemia is limited. Several quantitative parameters have been proposed to enhance the specificity of cCTA, such as morphologic indices (lesion length/minimal lumen diameter(4) [LL/MLD(4)]; percentage aggregate plaque volume [%APV]) and a measure of intracoronary contrast gradients (corrected coronary opacification [CCO]). METHODS Forty-nine patients who had undergone cCTA followed by FFR within 3 months were included. An experienced observer visually assessed all cCTA studies and derived multiple measures characterizing the lesion of interest, including LL, MLD, minimal lumen area (MLA), LL/MLD(4), remodeling index, %APV, and CCO. Lesion-specific ischemia was considered with FFR <0.8. RESULTS Among 56 lesions, 13 were flow-obstructing by FFR. On univariate analysis, LL, MLD, LL/MLD(4), and CCO showed discriminatory power. The area under the curve of LL/MLD(4) (0.909) was significantly greater compared with MLD (0.802, P = 0.014), LL (0.739, P = 0.041), and CCO (0.809), although the latter did not reach statistical significance (P = 0.175). On multivariate regression, LL/MLD(4) was the only independent predictor of lesion-specific ischemia (odds ratio 2.021, P = 0.001). Moreover, LL/MLD(4) compared favorably to visual cCTA evaluation. CONCLUSION LL/MLD(4) derived from routine cCTA can enhance the detection of lesion-specific ischemia and may be superior to other described quantitative parameters.

Imaging Coronary Artery Disease and the Myocardial Ischemic Cascade : Clinical Principles and Scope

On a subcellular level, atherogenesis is characterized by the translocation of proatherogenic lipoproteins into the arterial wall. An inflammatory response involving complex repair mechanisms subsequently causes maladaptive vascular changes resulting in coronary stenosis or occlusion. The chronology of the underlying processes occurring from atherosclerosis to myocardial ischemia affect the selection and interpretation of diagnostic testing. An understanding of the ischemic cascade, atherosclerosis, coronary remodeling, plaque morphology, and their relationship to clinical syndromes is essential in determining which diagnostic modalities are useful in clinical practice.

HEMODYNAMICS OF STENOTIC AORTIC VALVE UNDER THE INFLUENCE OF CONTRACTILITY, PRELOAD, AND AFTERLOAD

Assessing the severity of aortic stenosis (AS) remains challenging, especially for low-flow, low-gradient AS. The purpose of this study was to characterize the effects of left ventricular (LV) contractility, compliance, preload, and afterload on hemodynamics of AS. A computer model was used to

Aortocoronary saphenous vein graft aneurysm causing high-gradient right ventricular outflow tract obstruction.

A 74-year-old man presented to our institution with worsening dyspnoea on exertion and fatigue 17 years after coronary artery bypass graft surgery (left internal mammary artery—left anterior descending, radial artery—diagonal branch, saphenous vein graft—right posterior descending, and saphenous vein graft—first obtuse marginal). A chest X-ray performed upon arrival showed a large left mediastinal density ( Panel A , arrow). The …