CT-Derived Fractional Flow Reserve (FFRCT): From Gatekeeping to Roadmapping.

Coronary computed tomography angiography (CCTA) has emerged as the preferred modality in the diagnosis of coronary artery disease, but it is limited by modest specificity. By applying principles of computational fluid dynamics, flow fraction reserve, a measure of lesion-specific ischemia that is used to guide revascularization, can be noninvasively derived from CCTA, the so-called computed tomography-derived flow fractional reserve (FFRCT). The accuracy of FFRCT in discriminating ischemia has been extensively validated, and it has been shown to improve the specificity of CCTA. Compared to other stress myocardial perfusion imaging, FFRCT has superior or comparable accuracy. Clinical studies have provided strong evidence that FFRCT has significant prognostic implications and informs clinical decisions for revascularization, serving as a gatekeeper to invasive coronary angiography. In addition, FFRCT-based tools can be used to simulate the physiological consequences of different revascularization strategies, thus providing the roadmap to achieve complete revascularization. Although challenges remain, ongoing research and randomized controlled trials are expected to address current limitations and better define its role in clinical practice.

Cardiac Computed Tomography to exclude left atrial appendage thrombus in atrial arrhythmias prior to electrical cardioversion during the COVID-19 pandemic.

Nil.

Geometric differences of the mitral valve apparatus in atrial and ventricular functional mitral regurgitation.

BACKGROUND: Functional mitral regurgitation (FMR) occurs in patients with annular dilation (atrial, aFMR) or patients with left ventricular (LV) disease (ventricular, vFMR). Meticulous understanding of the mechanisms underpinning regurgitation is crucial to optimize therapeutic strategies. METHODS: Patients with moderate-severe FMR were identified from a registry of patients referred for transcatheter mitral valve intervention. In addition, controls without cardiovascular disease were identified. Differences in the geometry of the LV and mitral valve apparatus (including leaflet and tenting geometry, papillary muscle displacement and movement, annular dimensions, and dynamism) between atrial and ventricular FMR, and control subjects, were assessed using multiphasic cardiac CT. RESULTS: Of 183 FMR patients, 18 patients (10%) were found to have aFMR. The remaining patients had either ischemic or non-ischemic ventricular FMR. In aFMR, both increasing LV end-systolic volume (rho 0.701, p â€‹< â€‹0.01) and left atrial volume (rho 0.909, p â€‹< â€‹0.01) were associated with larger annular area. By contrast, in vFMR larger annular area was most strongly associated with larger left atrial volume (rho 0.63, p â€‹< â€‹0.01). In controls, increased annular area was associated with larger LVEDV (rho 0.78, p â€‹< â€‹0.01) and LVESV (rho 0.824, p â€‹< â€‹0.01), but not left atrial size (rho 0.16, p â€‹= â€‹0.45). Ventricular FMR comprised apicolaterally displaced, akinetic posteromedial papillary muscles, resulting in pronounced leaflet tethering, leaflet elongation compared to controls, and only modest relative LA dilatation. Compared to vFMR, aFMR was characterised by marked relative annular dilation, smaller but discernible mitral valve tenting, shorter leaflet lengths when related to annular size, but normal papillary geometry. CONCLUSION: FMR is characterised by multiple changes within the mitral valve complex. Atrial and ventricular FMR differ significantly in terms of the drivers of annular size, and geometry and function of the subvalvular apparatus. This highlights the need to consider these as separate disease entities.

Neo-LVOT and Transcatheter Mitral Valve Replacement: Expert Recommendations.

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 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.

Impact of the updated diastolic function guidelines in the real world.

BACKGROUND: Echocardiographic assessment of diastolic function is complex but can aid in the diagnosis of heart failure, particularly in patients with preserved ejection fraction. In 2016, the American Society of Echocardiography (ASE) and European Association of Cardiovascular Imaging (EACVI) published an updated algorithm for the evaluation of diastolic function. The objective of our study was to assess its impact on diastolic function assessment in a real-world cohort of echo studies. METHODS: We retrospectively identified 71,727 consecutive transthoracic echo studies performed at a tertiary care center between February 2010 and March 2016 in which diastolic function was reported based on the 2009 ASE Guidelines. We then programmed a software algorithm to assess diastolic function in these echo studies according to the 2016 ASE/EACVI Guidelines. RESULTS: When diastolic function assessment based on the 2009 guidelines was compared to that using the 2016 guidelines, there were significant differences in proportion of studies classified as normal (23% vs. 32%) or indeterminate (43% vs. 36%) function, and mild (23% vs. 23%), moderate (10% vs. 8%), or severe (1% vs. 2%) diastolic dysfunction, with poor agreement between the two methods (Kappa 0.323, 95% CI 0.318-0.328). Furthermore, within the subgroup of studies with preserved ejection fraction and no evidence of myocardial disease, there was significant reclassification from mild diastolic dysfunction to normal diastolic function. CONCLUSION: The updated guidelines result in significant differences in diastolic function interpretation in the real world. Our findings have important implications for the identification of patients with or at risk for heart failure.

Initiation and maintenance of statins and aspirin after acute coronary syndromes (ANZACS-QI 11).

INTRODUCTION Prior New Zealand studies suggest that only approximately two-thirds of patients who present with an acute coronary syndrome (ACS) are maintained on a statin/aspirin post-discharge. This could be due to sub-optimal initiation or poor longer-term adherence. AIM To identify the pattern of statin/aspirin maintenance following ACS from initial prescription to 3 years post-discharge. METHODS All New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) registry data for consecutive New Zealand residents (2007-2011), who were hospitalised with ACS, were anonymously linked to national datasets to derive a medication possession ratio (MPR) to assess medication maintenance. An MPR ≥ 0.8 is considered adequate maintenance. RESULTS Of the 1846 patients discharged alive, 95% were prescribed a statin at discharge and 92% were dispensed a statin within 3 months, but only 75% had a MPR ≥ 0.8 in the first year, and 67% in year 3. In the same cohort, 98% were prescribed aspirin and 88% were dispensed aspirin within the 3 months of discharge. In the first year, 72% had an aspirin MPR ≥ 0.8 and 71% maintained this in year 3. Fifty-nine percent were maintained on both aspirin and a statin in the third year, but 20% were maintained on neither. Regression analysis identified the independent predictors of inadequate maintenance in the third year as age < 45 years, no prior statin, and Maori and Pacific ethnicity. CONCLUSION Longer-term maintenance of evidenced-based secondary prevention medications after ACS is suboptimal despite high levels of initial prescribing and dispensing. Understanding the barriers to longer-term maintenance is required to improve patient outcomes.