Comprehensive Myocardial Assessment by Computed Tomography: Impact on Short-Term Outcomes After Transcatheter Aortic Valve Replacement.

BACKGROUND: Quantification of myocardial changes in severe aortic stenosis (AS) is prognostically important. The potential for comprehensive myocardial assessment pre-transcatheter aortic valve replacement (TAVR) by computed tomography angiography (CTA) is unknown. OBJECTIVES: This study sought to evaluate whether quantification of left ventricular (LV) extracellular volume-a marker of myocardial fibrosis-and global longitudinal strain-a marker of myocardial deformation-at baseline CTA associate with post-TAVR outcomes. METHODS: Consecutive patients with symptomatic severe AS between January 2021 and June 2022 who underwent pre-TAVR CTA were included. Computed tomography extracellular volume (CT-ECV) was derived from septum tracing after generating the 3-dimensional CT-ECV map. Computed tomography global longitudinal strain (CT-GLS) used semi-automated feature tracking analysis. The clinical endpoint was the composite outcome of all-cause mortality and heart failure hospitalization. RESULTS: Among the 300 patients (80.0 ± 9.4 years of age, 45% female, median Society of Thoracic Surgeons Predicted Risk of Mortality score 2.80%), the left ventricular ejection fraction (LVEF) was 58% ± 12%, the median CT-ECV was 28.5% (IQR: 26.2%-32.1%), and the median CT-GLS was -20.1% (IQR: -23.8% to -16.3%). Over a median follow-up of 16 months (IQR: 12-22 months), 38 deaths and 70 composite outcomes occurred. Multivariable Cox proportional hazards model, accounting for clinical and echocardiographic variables, demonstrated that CT-ECV (HR: 1.09 [95% CI: 1.02-1.16]; P = 0.008) and CT-GLS (HR: 1.07 [95% CI: 1.01-1.13]; P = 0.017) associated with the composite outcome. In combination, elevated CT-ECV and CT-GLS (above median for each) showed a stronger association with the outcome (HR: 7.14 [95% CI: 2.63-19.36]; P < 0.001). CONCLUSIONS: Comprehensive myocardial quantification of CT-ECV and CT-GLS associated with post-TAVR outcomes in a contemporary low-risk cohort with mostly preserved LVEF. Whether these imaging biomarkers can be potentially used for the decision making including timing of AS intervention and post-TAVR follow-up will require integration into future clinical trials.

Feasibility of Redo-Transcatheter Aortic Valve Replacement in Sapien Valves Based on In Vivo Computed Tomography Assessment.

BACKGROUND: Our aim was to assess the feasibility of repeat transcatheter aortic valve (TAV) replacement for degenerated Sapien3 (S3) prostheses by simulating subsequent implantation of S3 or Evolut, using in vivo computed tomography-based sizing and the impact on coronary and patient-prosthesis mismatch risks. METHODS: Computed tomography scans from 356 patients with prior S3 TAV replacement implantation were analyzed. The in vivo sizing for second TAV based on averaged area of 3 levels of outflow, mid (narrowest) and inflow, was compared with in vitro recommendations, that is, same size as index S3 for second S3 and 1 size larger for Evolut. Risks of coronary obstruction and patient-prosthesis mismatch were determined by valve-to-aorta distance and estimated effective orifice area, respectively. RESULTS: Overall, the majority of patients (n=328; 92.1%) had underexpanded index S3 with an expansion area of 94% (91%-97%), leading to significant differences in size selection of the second TAV between in vivo and in vitro sizing strategies. Expansion area <89% served as a threshold, resulting in 1 size smaller than the in vitro recommendations were selected in 45 patients (13%) for S3-in-S3 and 13 (4%) for Evolut-in-S3, while the remaining patients followed in vitro recommendations (P<0.01, in vivo versus in vitro sizing). Overall, 57% of total patients for S3-in-S3 simulation and 60% for Evolut-in-S3 were considered low risk for coronary complications. Deep index S3 implantation (odds ratio, 0.76 [interquartile range, 0.67-0.87]; P<0.001) and selecting Evolut as the second TAV (11% risk reduction in intermediate- or high-risk patients) reduced coronary risk. Estimated moderate or severe patient-prosthesis mismatch risk was 21% for S3-in-S3 and 1% for Evolut-in-S3, assuming optimal expansion of the second TAV. CONCLUSIONS: Redo-TAV replacement with S3-in-S3 and Evolut-in-S3 could be feasible with low risk to coronaries in ≈60% of patients, while the remaining 40% will be at intermediate or high risk. The feasibility of redo-TAV replacement is influenced by sizing strategy, type of second TAV, native annular anatomy, and implant depth.

Importance of imaging-acquisition protocol and post-processing analysis for extracellular volume fraction assessment by computed tomography.

BACKGROUND: Computed tomography angiography (CTA) assessment of myocardial extracellular volume fraction (CT-ECV) is feasible, although the protocols for imaging acquisition and post-processing methodology have varied. We aimed to identify a pragmatic protocol for CT-ECV assessment encompassing both imaging acquisition and post-processing methodologies to facilitate its clinical implementation. METHODS: We evaluated consecutive patients with severe aortic stenosis undergoing evaluation for transcatheter aortic valve replacement (TAVR). Pre-contrast and 3-min-delayed CTA were obtained in systole using either helical prospective-ECG-triggered (high-pitch) or axial sequential-ECG-gated acquisition, adding to standard TAVR CTA protocol. Using a dedicated software for co-registration of CTA datasets, three methodologies for ECV measurement were evaluated: (1) mid-septum region of interest (Septal ECV), (2) averaged-global ECV (Global ECV) encompassing 16-AHA segments, and (3) average of septal and lateral segments (Averaged ECVsep and Averaged ECVlat). RESULTS: Among the 142 patients enrolled (median â€‹= â€‹81 years, 44% females), 8 were excluded due to significant imaging artifacts precluding Global ECV assessment. High-pitch scan mode was performed in 68 patients (48%). Suboptimal image quality for Global ECV assessment was associated with high-pitch scan mode (odds ratio: OR â€‹= â€‹2.26, p â€‹= â€‹0.036), along with the presence of intracardiac leads (OR â€‹= â€‹4.91, p â€‹= â€‹0.002), and BMI≥35 â€‹kg/m2 (OR â€‹= â€‹2.80, p â€‹= â€‹0.026). Septal ECV [median â€‹= â€‹29.4%] and Averaged ECVsep [29.0%] were similar (p â€‹= â€‹0.108), while Averaged ECVlat [27.5%] was lower than Averaged ECVsep (p â€‹< â€‹0.001), resulting in lower Global ECV [28.6%]. CONCLUSIONS: Myocardial CT-ECV assessment is feasible using a systolic sequential acquisition pre-contrast, and similar additional 3-min delayed scan. Septal ECV measurement provides similar values to Global ECV and is equally reproducible.

Association of Left Ventricular Remodeling Assessment by Cardiac Magnetic Resonance With Outcomes in Patients With Chronic Aortic Regurgitation.

Importance: Chronic aortic regurgitation (AR) causes left ventricular (LV) volume overload, which results in progressive LV remodeling negatively affecting outcomes. Whether cardiac magnetic resonance (CMR) volumetric quantification can provide incremental risk stratification over standard clinical and echocardiographic evaluation in patients with chronic moderate or severe AR is unknown. Objective: To compare LV remodeling measurements by CMR and echocardiography between patients with and without heart failure symptoms and to verify the association of remodeling measurements of patients with chronic moderate or severe AR but no or minimal symptoms with clinical outcomes receiving medical management. Design, Setting, and Participants: This multicenter retrospective cohort study included consecutive patients with at least moderate chronic native AR evaluated by 2-dimensional transthoracic echocardiography and CMR examination within 90 days from each other between January 2012 and February 2020 at Allina Health System. Data were analyzed from June 2021 to January 2022. Exposures: Clinical evaluation and risk stratification by CMR. Main Outcomes and Measures: The end point was a composite of death, heart failure hospitalization, or progression of New York Heart Association functional class while receiving medical management, censoring patients at the time of aortic valve replacement (when performed) or at the end of follow-up. Results: Of the 178 included patients, 119 (66.9%) were male, 158 (88.8%) presented with no or minimal symptoms (New York Heart Association class I or II), and the median (IQR) age was 58 (44-69) years. Compared with patients with no or minimal symptoms, symptomatic patients had greater LV end-systolic volume index (LVESVi) by CMR (median [IQR], 66 [46-85] mL/m2 vs 42 [30-58] mL/m2; P < .001), while there were no significant differences by echocardiography (LVESVi: median [IQR], 38 [30-58] mL/m2 vs 27 [20-42] mL/m2; P = .07; LV end-systolic diameter index: median [IQR], 21 [17-25] mm/m2 vs 18 [15-22] mm/m2; P = .17). During the median (IQR) follow-up of 3.3 (1.6-5.8) years, 50 patients with no or minimal symptoms receiving medical management developed the composite end point, which, in multivariate analysis adjusted for age and EuroSCORE II, was independently associated with LVESVi of 45 mL/m2 or greater and aortic regurgitant fraction of 32% or greater, the latter adding incremental prognostic value to CMR volumetric assessment. Conclusions and Relevance: In patients with chronic moderate or severe AR, patients presenting with heart failure symptoms have greater LVESVi by CMR than those with no or minimal symptoms. In patients with no or minimal symptoms, CMR quantification of LVESVi and AR severity may identify those at risk of death or incident heart failure and therefore should be considered in the clinical evaluation and decision-making of these patients.

Clinical academic research in the time of Corona: A simulation study in England and a call for action.

OBJECTIVES: We aimed to model the impact of coronavirus (COVID-19) on the clinical academic response in England, and to provide recommendations for COVID-related research. DESIGN: A stochastic model to determine clinical academic capacity in England, incorporating the following key factors which affect the ability to conduct research in the COVID-19 climate: (i) infection growth rate and population infection rate (from UK COVID-19 statistics and WHO); (ii) strain on the healthcare system (from published model); and (iii) availability of clinical academic staff with appropriate skillsets affected by frontline clinical activity and sickness (from UK statistics). SETTING: Clinical academics in primary and secondary care in England. PARTICIPANTS: Equivalent of 3200 full-time clinical academics in England. INTERVENTIONS: Four policy approaches to COVID-19 with differing population infection rates: "Italy model" (6%), "mitigation" (10%), "relaxed mitigation" (40%) and "do-nothing" (80%) scenarios. Low and high strain on the health system (no clinical academics able to do research at 10% and 5% infection rate, respectively. MAIN OUTCOME MEASURES: Number of full-time clinical academics available to conduct clinical research during the pandemic in England. RESULTS: In the "Italy model", "mitigation", "relaxed mitigation" and "do-nothing" scenarios, from 5 March 2020 the duration (days) and peak infection rates (%) are 95(2.4%), 115(2.5%), 240(5.3%) and 240(16.7%) respectively. Near complete attrition of academia (87% reduction, <400 clinical academics) occurs 35 days after pandemic start for 11, 34, 62, 76 days respectively-with no clinical academics at all for 37 days in the "do-nothing" scenario. Restoration of normal academic workforce (80% of normal capacity) takes 11, 12, 30 and 26 weeks respectively. CONCLUSIONS: Pandemic COVID-19 crushes the science needed at system level. National policies mitigate, but the academic community needs to adapt. We highlight six key strategies: radical prioritisation (eg 3-4 research ideas per institution), deep resourcing, non-standard leadership (repurposing of key non-frontline teams), rationalisation (profoundly simple approaches), careful site selection (eg protected sites with large academic backup) and complete suspension of academic competition with collaborative approaches.

Invasive versus non-invasive assessment of valvuloarterial impedance in severe aortic stenosis.

BACKGROUND: As a measure of the global left ventricular afterload, valvuloarterial impedance (ZVA) can be estimated using transthoracic echocardiography (TTE) and invasive measuring methods. The objective of this study was to compare the performance of TTE in measuring ZVA with invasive haemodynamics, direct Fick and thermodilution (TD), in patients with severe aortic stenosis (AS). METHODS: This is a retrospective cohort study of 66 patients with severe AS who underwent TTE and bilateral heart catheterisation preaortic valve replacement. ZVA was calculated non-invasively from TTE and invasively using TD and Fick. The differences in measurements were estimated using a generalised estimating equation approach. The exchangeability of the measurements from different methods was evaluated under binary risk stratification rules. RESULTS: The mean±SD ZVA by TTE was 4.6±1.4 vs 4.9±1.6 by TD vs 4.3±1.2 mm Hg m2/mL by Fick. From multivariate analyses, ZVA by TTE was 5.9% (95% CI -15.0 to 2.5) lower than by TD and 5.9% (95% CI -1.5 to 12.8) higher than by Fick. At the same time, ZVA by TD was 12.5% (3.0 to 22.9) higher than with Fick. Risk classifications for ZVA-based binary decision rules showed poor agreement between TTE and invasive methods (kappa ≤0.3). CONCLUSIONS: The differences in ZVA estimates between TTE and invasive standards do not appear to exceed those between the standards. As such TTE-based estimates may be deemed acceptable as a clinical measure of global haemodynamic load. However, TTE-based and invasive measurements may not be interchangeable to identify patients at risk using binary classification rules based on ZVA.

Multimodality Assessment of Anomalous Aortic Origin of the Right Coronary Artery Presenting With Cardiac Arrest.

Anomalous aortic origin of coronary artery (AAOCA) can range from benign anatomic variants to those presenting with sudden cardiac arrest. This unique case of right AAOCA demonstrates detailed anatomic findings from cardiac computed tomography and the effects of transient acute coronary ischemia by cardiac magnetic resonance. (Level of Difficulty: Advanced.).

Assessment of Cardiac Damage in Aortic Stenosis.

Severe aortic stenosis (AS) causes chronic pressure overload of the left ventricle (LV), resulting in the progressive cardiac damage, which extends beyond the LV. Several previous studies have shown a relationship of the cardiac damage to AS, rather than the stenosis severity, with adverse events after aortic valve replacement (AVR) in patients with severe AS. A new staging system for AS patients has important prognostic implications for clinical outcomes after AVR. This review summarizes the importance of assessment of cardiac damage in patients with AS.

Assessment of Aortic Stenosis by Cardiac Magnetic Resonance Imaging: Quantification of Flow, Characterization of Myocardial Injury, Transcatheter Aortic Valve Replacement Planning, and More.

Cardiac MR (CMR) imaging contributes uniquely to the comprehensive assessment and management of aortic stenosis (AS), beyond the information provided by transthoracic echocardiography. The severity of AS and subsequent ventricular remodeling response can be assessed using cine images and phase-contrast mapping. CMR imaging also identifies myocardial tissue characteristics, which are valuable markers of left ventricular decompensation and adverse outcomes in AS. CMR imaging may be used as an alternative modality for transcatheter aortic valve replacement (TAVR) planning and post-TAVR management. This article explores the clinical utility of CMR imaging evaluation.

Imaging Assessment of Tricuspid Regurgitation Severity.

Assessing the severity of tricuspid regurgitation remains a challenging task, and although echocardiography is the test of choice, significant limitations of the current recommendations exist. Newer methods have been used in current trials of transcatheter devices and may improve our understanding of the disease process. Cardiac magnetic resonance imaging and computed tomography angiography may play significant roles as adjunctive imaging modalities. This paper reviews the imaging modalities currently used to quantify tricuspid regurgitation severity.

Global longitudinal strain assessment by computed tomography in severe aortic stenosis patients - Feasibility using feature tracking analysis.

BACKGROUND: Global longitudinal strain (GLS) detects subclinical myocardial changes in patients with aortic stenosis (AS). Although GLS is typically measured by transthoracic echocardiography (TTE), assessment by multiphasic gated computed tomography angiography (CTA) has become recently available. We sought to evaluate the feasibility of CTA-derived GLS assessment and compare its agreement with TTE using the same post-processing software in severe AS patients undergoing transcatheter aortic valve replacement (TAVR) evaluation. METHODS: We evaluated patients with severe AS, sinus rhythm and adequate image quality for GLS analysis by both CTA and TTE pre-TAVR using 2D CT-Cardiac Performance Analysis prototype software (TomTec). The 18-segment model was used for GLS analysis by averaging the three long-axis views in both CTA and TTE studies. Agreement was assessed using linear regression and Bland-Altman analysis. RESULTS: A total of 123 consecutive patients were included (mean age 84 ±â€¯7 years, 45% female). The mean left ventricular ejection fraction (LVEF) by CTA and TTE were similar 53 ±â€¯14% for both. On average, CTA-derived GLS was greater than by TTE (-20 ±â€¯6.5% vs. -16 ±â€¯4.9%, respectively, p < 0.001). There was a moderate correlation between GLS assessed by CTA vs. TTE (r = 0.62, p < 0.001), although variability between imaging methods existed. The correlation between GLS and LVEF was strong (r = -0.90, p < 0.001 for CTA, r = -0.88, p < 0.001 for TTE) using the same imaging modality. CONCLUSION: CTA-derived GLS assessment is feasible in selected patients with sinus rhythm and adequate image quality. The agreement of GLS between TTE and CTA is moderate but not interchangeable suggesting a potential modality-specific GLS threshold.

Is there a role for diastolic function assessment in era of delayed enhancement cardiac magnetic resonance imaging?: a multimodality imaging study in patients with advanced ischemic cardiomyopathy.

UNLABELLED: Cardiac magnetic resonance (CMR) identifies important prognostic variables in ischemic cardiomyopathy (ICM) patients such as left ventricular (LV) volumes, LV ejection fraction (LVEF), peri-infarct zone, and myocardial scar burden (MSB). It is unknown whether Doppler-based diastolic dysfunction (DDF) retains its prognostic value in ICM patients, in the context of current imaging, medical, and device therapies. METHODS: Diastolic function was evaluated in ICM patients (LVEF ≤ 40% and ≥ 70% stenosis in ≥ 1 coronary artery) who underwent transthoracic echocardiogram and delayed hyperenhancement CMR studies within 7 days. The association of DDF with the combined end point was assessed after risk-adjustment using Cox proportional hazards models. RESULTS: A total of 360 patients with severe LV dysfunction (LVEF = 24 ± 9%) and extensive MSB (31 ± 17%) were evaluated; DDF was present in all patients (stage 1%-44%, stage 2%-25%, stage 3%-31%). There were 130 events (124 deaths and 6 heart transplants) over a median follow-up of 5.8 years (IQR, 3.7-7.4 years). On multivariable analysis, DDF > stage 1 (HR, 1.37; P = .007) was associated with the combined end-point, independent of clinical risk score (HR, 2.40; P < .0001), implantable cardioverter defibrillator implantation (HR, 0.60; P = .009), incomplete revascularization (HR, 1.32; P = .003), mitral regurgitation (HR, 3.37; P = .01), peri-infarct zone area (HR, 1.04; P = 0.02), and MSB (HR, 1.02; P = .01). DDF had incremental prognostic value for the combined end-point (model χ(2) increased from 89 to 95, P = .02). CONCLUSION: DDF is a powerful predictor of mortality in ICM patients with significant LV dysfunction, independent of clinical and CMR data. DDF assessment provides incremental value, improving risk stratification.

Two-dimensional longitudinal strain assessment in the presence of myocardial contrast agents is only feasible with speckle-tracking after microbubble destruction.

BACKGROUND: Longitudinal strain (LS) imaging is an important tool for the quantification of left ventricular function and deformation, but its assessment is challenging in the presence of echocardiographic contrast agents (CAs). The aim of this study was to test the hypothesis that destruction of microbubbles using high mechanical index (MI) could allow the measurement of LS. METHODS: LS was measured using speckle strain (speckle-tracking LS [STLS]) and Velocity Vector Imaging (VVI) before and after CA administration in 30 consecutive patients. Low MI was used for left ventricular opacification and three-dimensional high MI for microbubble destruction. Four different settings were tested over 60 sec: (1) baseline LS without contrast, (2) LS after CA administration with low MI (0.3), (3) LS after CA administration with high MI (0.9), and (4) LS after microbubble destruction with high MI and three-dimensional imaging. RESULTS: Baseline feasibility of LS assessment (99.3% and 98.2% with STLS and VVI, respectively) was reduced after CA administration using STLS at low (69%, P < .0001) and high (95.4%, P = .0002) MI as well as with VVI (93.8%, P = .004, and 84.7%, P < .0001, respectively). STLS assessment was feasible with high MI after microbubble destruction (1.7% of uninterpretable segments vs 0.7%, P = .26) but not using VVI (7.2% vs 1.8%, P < .001). Regardless of which microbubbles or image settings were used, VVI was associated with significant variability and overestimation of global LS (for low MI, +4.7%, P < .01; for high MI, +3.3%, P < .001; for high MI after microbubble destruction, +1.3%, P = .04). CONCLUSIONS: LS assessment is most feasible without contrast. If a CA is necessary, the calculation of LS is feasible using the speckle-tracking method, if three-dimensional imaging is used as a tool for microbubble destruction 1 min after CA administration.