In the absence of disease impacting the coronary arteries or myocardium, there exists a linear relationship between vessel volume and myocardial mass to ensure balanced distribution of blood supply... Show moreIn the absence of disease impacting the coronary arteries or myocardium, there exists a linear relationship between vessel volume and myocardial mass to ensure balanced distribution of blood supply. This balance may be disturbed in diseases of either the coronary artery tree, the myocardium, or both. However, in contemporary evaluation the coronary artery anatomy and myocardium are assessed separately. Recently the coronary lumen volume to myocardial mass ratio (V/M), measured noninvasively using coronary computed tomography angiography (CTCA), has emerged as an integrated measure of myocardial blood supply and demand in vivo. This has the potential to yield new insights into diseases where this balance is altered, thus impacting clinical diagnoses and management.In this review, we outline the scientific methodology underpinning CTCA-derived measurement of V/M. We describe recent studies describing alterations in V/M across a range of cardiovascular conditions, including coronary artery disease, cardiomyopathies and coronary microvascular dysfunction. Lastly, we highlight areas of unmet research need and future directions, where V/M may further enhance our understanding of the pathophysiology of cardiovascular disease. Show less
Background: The role of change in fractional flow reserve derived from CT (FFRCT) across coronary stenoses (Delta FFRCT) in guiding downstream testing in patients with stable coronary artery... Show moreBackground: The role of change in fractional flow reserve derived from CT (FFRCT) across coronary stenoses (Delta FFRCT) in guiding downstream testing in patients with stable coronary artery disease (CAD) is unknown. Objectives: To investigate the incremental value of Delta FFRCT in predicting early revascularization and improving efficiency of catheter laboratory utilization. Materials: Patients with CAD on coronary CT angiography (CCTA) were enrolled in an international multicenter registry. Stenosis severity was assessed as per CAD-Reporting and Data System (CAD-RADS), and lesion-specific FFRCT was measured 2 cm distal to stenosis. Delta FFRCT was manually measured as the difference of FFRCT across visible stenosis. Results: Of 4730 patients (66 +/- 10 years; 34% female), 42.7% underwent ICA and 24.7% underwent early revascularization. AFFRCT remained an independent predictor for early revascularization (odds ratio per 0.05 increase [95% confidence interval], 1.31 [1.26-1.35]; p < 0.001) after adjusting for risk factors, stenosis features, and lesion-specific FFRCT. Among the 3 models (model 1: risk factors + stenosis type and location + CAD-RADS; model 2: model 1 + FFRCT; model 3: model 2 + AFFRCT), model 3 improved discrimination compared to model 2 (area under the curve, 0.87 [0.86-0.88] vs 0.85 [0.84-0.86]; p < 0.001), with the greatest incremental value for FFRCT 0.71-0.80. AFFRCT of 0.13 was the optimal cut-off as determined by the Youden index. In patients with CAD-RADS >3 and lesion-specific FFRCT <0.8, a diagnostic strategy incorporating AFFRCT >0.13, would potentially reduce ICA by 32.2% (1638-1110, p < 0.001) and improve the revascularization to ICA ratio from 65.2% to 73.1%. Conclusions: AFFRCT improves the discrimination of patients who underwent early revascularization compared to a standard diagnostic strategy of CCTA with FFRCT, particularly for those with FFRCT 0.71-0.80. AFFRCT has the potential to aid decision-making for ICA referral and improve efficiency of catheter laboratory utilization. Show less
OBJECTIVES This study sought to investigate the impact of computed tomography (CT)-based area and perimeter oversizing on the incidence of paravalvular regurgitation (PVR) and valve hemodynamics in... Show moreOBJECTIVES This study sought to investigate the impact of computed tomography (CT)-based area and perimeter oversizing on the incidence of paravalvular regurgitation (PVR) and valve hemodynamics in patients treated with the SAPIEN 3 transcatheter heart valve (THV).BACKGROUND The incremental value of considering annular perimeter or left ventricular outflow tract measurements and the impact of THV oversizing on valve hemodynamics are not well defined.METHODS The PARTNER 3 (Placement of Aortic Transcatheter Valves 3) trial included 495 low-surgical-risk patients with severe aortic stenosis who underwent THV implantation. THV sizing was based on annular area assessed by CT. Area and perimeter-based oversizing was determined using systolic annular CT dimensions and nominal dimensions of the implanted THV. PVR, effective orifice area, and mean gradient were assessed on 30-day transthoracic echocardiography.RESULTS Of 485 patients with available CT and echocardiography data, mean oversizing was 7.9 +/- 8.7% for the annulus area and 2.1 +/- 4.1% for the perimeter. A very low incidence of >= moderate PVR (0.6%) was observed, including patients with minimal annular oversizing. Incidence of >= mild PVR and need for procedural post-dilatation were inversely related to the degree of oversizing. For patients with annular dimensions suitable for 2 THV sizes, the larger THV with both area and perimeter oversizing was associated with the lowest incidence of >= mild PVR (12.0% vs 43.4%; P < 0.0001). Left ventricular outflow tract area oversizing was not associated with PVR. THV prosthesis size, rather than degree of oversizing, had greatest impact on effective orifice area and mean gradient.CONCLUSIONS In low-surgical-risk patients, a low incidence of >= moderate PVR was observed, including patients with minimal THV oversizing. The degree of prosthesis oversizing had the greatest impact on reducing mild PVR and incidence of post-dilatation, without impacting valve hemodynamics. In selected patients with annular dimensions in between 2 valve sizes, the larger THV device oversized to both the annular area and perimeter reduced PVR and optimized THV hemodynamics. (C) 2021 Published by Elsevier on behalf of the American College of Cardiology Foundation. Show less
Reid, A.; Zekry, S. ben; Turaga, M.; Tarazi, S.; Bax, J.J.; Wang, D.D.; ... ; Leipsic, J. 2021
With the advent of transcatheter mitral valve replacement (TMVR), the concept of the neo-left ventricular outflow tract (LVOT) was introduced and remains an essential component of treatment... Show moreWith the advent of transcatheter mitral valve replacement (TMVR), the concept of the neo-left ventricular outflow tract (LVOT) was introduced and remains an essential component of treatment planning. This paper describes the LVOT anatomy and provides a step-by-step computed tomography methodology to segment and measure the neo-LVOT while discussing the current evidence and outstanding challenges. It also discusses the technical and hemodynamic factors that play a major role in assessing the neo-LVOT. A summary of expert-based recommendations about the overall risk of LVOT obstruction in different scenarios is presented along with the currently available methods to reduce the risk of LVOT obstruction and other post-procedural complications. (C) 2021 by the American College of Cardiology Foundation. Show less
