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

BackgroundFunctional 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.MethodsPatients 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.ResultsOf 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 ?< ?0.01) and left atrial volume (rho 0.909, p ?< ?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 ?< ?0.01). In controls, increased annular area was associated with larger LVEDV (rho 0.78, p ?< ?0.01) and LVESV (rho 0.824, p ?< ?0.01), but not left atrial size (rho 0.16, p ?= ?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.ConclusionFMR 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.     

Clinical impact of mitral calcium volume in patients undergoing transcatheter aortic valve implantation

BackgroundMitral annular calcification (MAC) has been associated with mitral valve (MV) disease and cardiovascular events in patients undergoing transcatheter aortic valve implantation (TAVI). We aimed to investigate the incidence and impact of mitral calcium volume (MCV) quantified by multidetector computed tomography (MDCT) on MV function and clinical outcomes after TAVI.MethodsConsecutive patients with exploitable echocardiography and MDCT performed during TAVI screening were enrolled in this retrospective analysis. Mitral calcium was assessed visually and measured using a semi-automatic tool developed for the aortic valve in an off-label fashion.ResultsMCV >0 mm³ was found in 65% of the 875 included patients. Patients with calcification were older (82 ± 6 versus 81 ± 7; P = 0.002) and had high prevalence of renal dysfunction (69% versus 61%; P = 0.017) and mitral stenosis (25% versus 4%, P < 0.001). MCV correlated well with visual MAC severity (r = 0.94; P < 0.001), but showed a greater predictive value for mitral stenosis (AUC = 0.804 vs. 0.780, P = 0.012) , while it was not a predictor of mitral regurgitation (AUC = 0.514). Correlations were found between MCV and echocardiographic parameters including MV area, mean transmitral gradient, and pressure half-time (P < 0.001 for all). MCV did not impact on cardiovascular mortality or new permanent pacemaker implantation after TAVI.ConclusionsCalcification of the mitral apparatus is common in TAVI candidates and results in mitral stenosis in 25% of the patients. Increasing MCV predicts mitral stenosis, but had no impact on clinical outcomes following TAVI.Clinical trial registrationNCT01368250.     

Dynamic computed tomographic assessment of the mitral annulus in patients with and without mitral prolapse

ObjectivesTo obtain 3D CT measurements of mitral annulus throughout cardiac cycle using prototype mitral modeling software, assess interobserver agreement, and compare among patients with mitral prolapse (MP) and control group.BackgroundPre-procedural imaging is critical for planning of transcatheter mitral valve (MV) replacement. However, there is limited data regarding reliable CT-based measurements to accurately characterize the dynamic geometry of the mitral annulus in patients with MV disease.MethodsPatients with MP and control subjects without any MV disease who underwent ECG-gated cardiac CT were retrospectively identified. Multiphasic CT data was loaded into a prototype mitral modeling software. Multiple anatomical parameters in 3D space were recorded throughout the cardiac cycle (0–95%): annular circumference, planar-surface-area (PSA), anterior-posterior (A-P) distance, and anterolateral-posteromedial (AL-PM) distance. Comparisons were made among the two groups, with p < 0.05 considered statistically significant. Interobserver agreement was assessed on ten patients using intraclass correlation coefficient (ICC) among 4 experienced readers.ResultsA total of 100 subjects were included: 50 with MP and 50 control. Annular dimensions were significantly higher in the MP group than control group, with circumference (144 ± 11 vs. 117±8 mm), PSA (1533 ± 247 vs. 1005 ± 142 mm²), A-P distance (38 ± 4 vs. 32±2 mm), and AL-PM distance (47 ± 4 vs. 39±3 mm) (all p < 0.001). Substantial size changes were observed throughout the cardiac cycle, but with maximal and minimal sizes at different cardiac phases for the two groups. The interobserver agreement was excellent (ICC≥0.75) for annular circumference, PSA, A-P- and AL-PM distance.ConclusionA significant variation in the mitral annular measures between different cardiac phases and two groups was observed with excellent interobserver agreement.     

Leaflet thrombosis following transcatheter aortic valve implantation

BackgroundTranscatheter aortic valve implantation (TAVI) is increasingly being offered to high-risk patients with symptomatic aortic valve stenosis. Recent reports have suggested a high incidence of subclinical leaflet thrombosis following bioprosthestic aortic valve replacement. We report the frequency and clinical presentation of leaflet thrombosis identified by cardiac CT in patients referred for follow-up contrast enhanced CT angiography following TAVI.Methods91 consecutive patients referred for follow-up contrast-enhanced CT angiography following TAVI were screened for inclusion in this analysis. Out of these, 13 patients were excluded. All CT examinations were performed using a 2nd or a 3rd generation dual-source system (Somatom Definition Flash/Force, Forchheim, Germany). In all patients, retrospectively ECG-gated spiral acquisition with tube modulation was performed to allow for assessment of leaflet motion. All prostheses were analyzed for presence of leaflet thrombosis defined as hypo-attenuated leaflet thickening with or without leaflet restriction. Post-procedural antithrombotic regimen as well as symptom status was documented in all patients.Results78 consecutive patients (35 males, 81 ± 4 years) were analyzed. TAVI had been performed in all patients (76 transfemoral access, 2 transapical access) with either balloon-expandable prostheses (4 Sapien XT, 64 Sapien 3) or self-expandable prostheses (5 SJM Portico, 5 Symetis Acurate). Follow-up CT angiography was performed at a median of 4 months following index procedure (Interquartile range 1 month). Leaflet thrombosis was detected in 18 patients (23%, 14 Sapien 3, 1 Sapien XT, 2 SJM Portico, 1 Symetis Acurate). In patients with leaflet thickening on CT, only 11% were on either oral anticoagulation or new oral anticoagulants versus 50% for patients with no leaflet thickening (p 0.002). In patients with leaflet thrombosis, 3 leaflets were affected in 5 patients, 2 leaflets in 5 patients and in 8 patient only 1 leaflet was affected. Clinical symptoms (angina, dyspnea or both) were reported in 2/18 patients with leaflet thrombosis (11%) and in both patients a significant increase of the mean echocardiographic gradient over the prosthesis was documented. The peak and mean echocardiographic gradients obtained at the day of CT examination was significantly higher in symptomatic patients versus asymptomatic patients (peak 46 ± 7 vs. 23 ± 11 mmHg, mean 29 ± 7 vs. 12 ± 6 mmHg, p = 0.01 and 0.002, respectively).Follow-up CT was available for 4 patients with complete resolution of the hypo-attenuated leaflet thickening following treatment.ConclusionLeaflet thrombosis following TAVI is a relatively frequent finding in patients referred for contrast enhanced CT angiography following TAVI. In the majority of patients it follows a subclinical course and is substantially more frequent in individuals who are not on oral anticoagulation. However, in patients with relevant increase in prosthetic gradients, symptomatic presentations are possible.     

Paravalvular leakage in transcatheter mitral valve replacement: Bringing simulation theory one step closer to reality

Transcatheter mitral valve replacement (TMVR) has emerged as a promising technique for the treatment of these patients with severe mitral valve disease and high or prohibitive surgical risk. Early experience with TMVR has shown a high rate of technical success and promising reductions in the severity of mitral regurgitation sustained out to 1 year post procedure. Despite this, procedural complications remain high, with the most common and significant of these being valve embolization, left ventricualr outflow tract (LVOT) obstruction and paravalvular leakage (PVL). It is this currently unanswered question that Morris et al. start to address in this issue of the Journal. They use the same annular segmentation and valve simulation as already proposed to predict LVOT obstruction, but use it to focus instead on examining the residual gap left between the base of the simulated transcatheter valve and the mitral leaflets or surgical prosthesis.     

Automated quantification of mitral valve geometry on multi-slice computed tomography in patients with dilated cardiomyopathy – Implications for transcatheter mitral valve replacement

ObjectivesThe primary aim of this study was to quantify the dimensions and geometry of the mitral valve complex in patients with dilated cardiomyopathy and significant mitral regurgitation. The secondary aim was to evaluate the validity of an automated segmentation algorithm for assessment of the mitral valve compared to manual assessment on computed tomography.BackgroundTranscatheter mitral valve replacement (TMVR) is an evolving technique which relies heavily on the lengthy evaluation of cardiac computed tomography (CT) datasets. Limited data is available on the dimensions and geometry of the mitral valve in pathological states throughout the cardiac cycle, which may have implications for TMVR device design, screening of suitable candidates and annular sizing prior to TMVR.MethodsA retrospective study of 15 of patients with dilated cardiomyopathy who had undergone full multiphase ECG gated cardiac CT. A comprehensive evaluation of mitral valve geometry was performed at 10 phases of the cardiac cycle using the recommended D-shaped mitral valve annulus (MA) segmentation model using manual and automated CT interpretation platforms. Mitral annular dimensions and geometries were compared between manual and automated methods.ResultsMitral valve dimensions in patients with dilated cardiomyopathy were similar to previously reported values (MA_area Diastole: 12.22 ± 1.90 cm²), with dynamic changes in size and geometry between systole and diastole of up to 5%. The distance from the centre of the MA to the left ventricular apex demonstrated moderate agreement between automated and manual methods (ρ_c = 0.90) with other measurements demonstrating poor agreement between the two methods (ρ_c = 0.75–0.86).ConclusionsVariability of mitral valve annulus measurements are small during the cardiac cycle. Novel automated algorithms to determine cardiac cycle variations in mitral valve geometry may offer improved segmentation accuracy as well as improved CT interpretation times.     

Automatic 3D aortic annulus sizing by computed tomography in the planning of transcatheter aortic valve implantation

Background

Accurate imaging assessment of aortic annulus (AoA) dimension is paramount to decide on the correct transcatheter heart valve (THV) size for patients undergoing transcatheter aortic valve implantation (TAVI). We evaluated the feasibility and accuracy of a novel automatic framework for multidetector row computed tomography (MDCT)-based TAVI planning.

Predicting the outcome of transcatheter mitral valve implantation using image-based computational models

BackgroundThe appropriate placement and size selection of mitral prostheses in transcatheter mitral valve implantation (TMVI) is critical, as encroachment on the left ventricular outflow tract (LVOT) may lead to flow obstruction. Recent advances in computed tomography (CT) can be employed for pre-procedural planning of mitral prosthetic valve placement. This study aims to develop patient-specific computational fluid dynamics models of the left ventricle (LV) in the presence of a mitral valve prosthesis to investigate blood flow and LVOT pressure gradient during systole.MethodsPatient-specific computational fluid dynamics simulations of TMVI with varied cardiac anatomy and insertion angles were performed (n = 30). Wide-volume full cycle cardiovascular CT images prior to TMVI were used as source anatomical data (n = 6 patients). Blood movement was governed by Navier-Stokes equations and the LV endocardial wall deformation was derived from each patient's CT images.ResultsThe computed pressure gradients in the presence of the mitral prosthesis compared well with clinically measured gradients. Analysis of the effects of prosthetic valve angulation, aorto-mitral annular angle, ejection fraction, LV size and new LVOT area (neo-LVOT) after TMVI in silico revealed that the neo-LVOT area (p < 0.001) was the most significant factor affecting LVOT pressure gradient. Angulation of the mitral valve can substantially mitigate LVOT gradient.ConclusionsComputational fluid dynamics simulation is a promising method to aid in pre-TMVI planning and understanding the factors underlying LVOT obstruction.     

The aortic valve calcium nodule score (AVCNS) independently predicts paravalvular regurgitation after transcatheter aortic valve replacement (TAVR)

BackgroundParavalvular regurgitation (PVR) is an important predictor of mortality after transcatheter aortic valve replacement (TAVR). Aortic valve (AV) calcification is strongly associated with PVR.ObjectivesThis study proposes a new metric to quantify AV total calcium burden and its composition in large calcium nodules (CNs) and explores its relation with PVR after TAVR.MethodsIn 133 patients that underwent TAVR, calcium burden of the AV was quantified with multidetector row CT as calcium mass. Each CN was characterized. The AV CN score (AVCNS) was defined as AV calcium mass × mass of the largest CN. PVR was assessed with echocardiography at 1 month. Logistic regression analysis was conducted to identify predictors of PVR.ResultsMean age was 84.1 ± 7.6 years (56% women). TAVR access was transapical in 56%. Procedural success was achieved in 92%. In-hospital mortality was 5%. At follow-up, the prevalence of absent/trace, mild, moderate, and severe PVR was 58%, 31%, 11%, and 0%, respectively. The only independent predictors of at least mild PVR were AVCNS (odds ratio [OR], 2.269; 95% CI, 1.433–3.593; P < .001), number of CNs on aortic annulus (OR, 1.822; 95% CI, 1.137–2.921; P = .013), and aortic annulus area (OR, 1.112; 95% CI, 1.010–1.223; P = .030). This model showed an area under the curve of 0.895 (95% CI, 0.830–0.960) for PVR prediction.ConclusionsAVCNS, a variable that comprises the total burden of AV calcification as well as calcification agglomeration in form of large nodules, is a novel and powerful independent predictor of PVR after TAVR.     

Clinical outcomes following transcatheter aortic valve implantation in patients with porcelain aorta

BackgroundCurrent guidelines favor transcatheter aortic valve implantation (TAVI) over surgical aortic valve replacement in patients with porcelain aorta (PAo). The clinical relevance of PAo in patients undergoing TAVI is however incompletely understood. The purpose of this study is to evaluate clinical outcome of patients with PAo undergoing TAVI.MethodsConsecutive patients undergoing TAVI were enrolled in a prospective single-center registry. Presence of PAo was evaluated by ECG-gated multi-slice computed tomography prior to the intervention. The primary endpoint was disabling stroke.ResultsAmong 2199 patients (mean age, 82.0 ?± ?6.3 years; 1135 females [51.6%]) undergoing TAVI between August 2007 and December 2019, 114 patients (5.2%) met VARC-2 criteria for PAo. Compared to individuals without PAo, patients with PAo were younger (79.4 ?± ?7.4 years vs. 82.1 ?± ?6.2 years; p ?< ?0.001), had a lower left ventricular ejection fraction (51.8 ?± ?14.9% vs. 55.3 ?± ?14.2%; p ?= ?0.009) and higher STS-PROM Scores (6.5 ?± ?4.3% vs. 4.9 ?± ?3.4%; p ?< ?0.001). At 1 year, disabling stroke occurred more often in patients with PAo (7.2%) than in those without (3.0%) (HR_adj, 2.49; 95% CI, 1.12–5.55). The risk difference emerged within 30 days after TAVI (HR_adj, 3.70; 95% CI, 1.52–9.03), and was driven by a high PAo-associated risk of disabling stroke in patients with alternative access (HR_adj, 5.79; 95% CI, 1.38–24.3), not in those with transfemoral (HR_adj, 1.47; 95% CI 0.45–4.85).ConclusionsTAVI patients with PAo had a more than three-fold increased risk of periprocedural disabling stroke compared to patients with no PAo. The difference was driven by a higher risk of stroke in patients treated by alternative access.     

Impact of computed-tomography defined sarcopenia on outcomes of older adults undergoing transcatheter aortic valve implantation

BackgroundThe adoption of Computed tomography (CT)-defined sarcopenia to risk stratify transcatheter aortic valve implantation (TAVI) candidates remains limited by a lack of both standardized definition and evidence of independent value over currently adopted mortality prediction tools.Methods391 consecutive TAVI patients with pre-procedural CT scan were included (81 ?± ?6 years, 57.5% male, STS-PROM score 4.4 ?± ?3.6%) and abdominal muscle retrospectively quantified. The two definitions of radiologic sarcopenia previously adopted in TAVI studies were compared (psoas muscle area [PMA] at the L4 vertebra level: “PMA-sarcopenia”; indexed skeletal muscle area at the L3 vertebra level: “SMI-sarcopenia”). The primary endpoint was longer available-term all-cause mortality. Secondary endpoints were Valve Academic Research Consortium-2-defined in-hospital and 30-day outcomes.ResultsSMI- and PMA-sarcopenia were present in 192 (49.1%) and 117 (29.9%) patients, respectively.After a median of 24 (12–30) months follow-up, 83 (21.2%) patients died. PMA-(adj-HR 1.81, 95%CI 1.12–2.93, p ?= ?0.015), but not SMI-sarcopenia (adj-HR 1.23, 95%CI 0.76–2.00, p ?= ?0.391), was associated with all-cause mortality independently of age, sex and in-study outcome predictors (atrial fibrillation, hemoglobin, history of peripheral artery disease, cancer and subcutaneous adipose tissue). PMA-defined sarcopenia provided additive prognostic value over current post-TAVI mortality risk estimators including STS-PROM (p ?= ?0.001), Euroscore II (p ?= ?0.025), Charlson index (p ?= ?0.025) and TAVI2-score (p ?= ?0.020). Device success, early safety, clinical efficacy and 30-day all-cause death were unaffected by sarcopenia status regardless of definition.ConclusionsPMA-sarcopenia (but not SMI-sarcopenia) is predictive of 2 year mortality among TAVI patients. The prognostic information provided by PMA-sarcopenia is independent of the tools currently adopted to predict post-TAVI mortality in clinical practice.     

Predicting paravalvular leak after transcatheter mitral valve replacement using commercially available software modeling

BackgroundThere is limited data identifying patients at risk for significant mitral regurgitation (MR) after transcatheter mitral valve replacement (TMVR). We hypothesized that software modeling based on computed tomography angiography (CTA) can predict the risk of moderate or severe MR after TMVR.Methods58 consecutive patients underwent TMVR at two institutions, including 31 valve-in-valve, 16 valve-in-ring, and 11 valve-in-mitral annular calcification. 12 (20%) patients developed moderate or severe MR due to paravalvular leak (PVL).ResultsThe software model correctly predicted 8 (67%) patients with significant PVL, resulting in sensitivity of 67%, specificity 96%, positive predictive value 89%, and negative predictive value 86%. There was excellent agreement between CTA readers using software modeling to predict PVL (kappa 0.92; p < 0.01). On univariate analysis, CTA predictors of moderate or severe PVL included presence of a gap between the virtual valve and mitral annulus on the software model (OR 48; p < 0.01), mitral annular area (OR 1.02; p 0.01), and % valve oversizing (OR 0.9; p 0.01). On multivariate analysis, only presence of a gap on the software model remained significant (OR 36.8; p < 0.01).ConclusionsSoftware modeling using pre-procedural CTA is a straightforward method for predicting the risk of moderate and severe MR due to PVL after TMVR.     

3D printing of the aortic annulus based on cardiovascular computed tomography: Preliminary experience in pre-procedural planning for aortic valve sizing

Backgroundto determine reliability and reproducibility of measurements of aortic annulus in 3D models printed from cardiovascular computed tomography (CCT) images.MethodsRetrospective study on the records of 20 patients who underwent aortic valve replacement (AVR) with pre-surgery annulus assessment by CCT and intra-operative sizing by Hegar dilators (IOS). 3D models were fabricated by fused deposition modelling of thermoplastic polyurethane filaments. For each patient, two 3D models were independently segmented, modelled and printed by two blinded “manufacturers”: a radiologist and a radiology technician. Two blinded cardiac surgeons performed the annulus diameter measurements by Hegar dilators on the two sets of models. Matched data from different measurements were analyzed with Wilcoxon test, Bland-Altmann plot and within-subject ANOVA.ResultsNo significant differences were found among the measurements made by each cardiac surgeon on the same 3D model (p = 0.48) or on the 3D models printed by different manufacturers (p = 0.25); also, no intraobserver variability (p = 0.46). The annulus diameter measured on 3D models showed good agreement with the reference CCT measurement (p = 0.68) and IOH sizing (p = 0.11). Time and cost per model were: model creation ∼10–15 min; printing time ∼60 min; post-processing ∼5min; material cost ∼1€. Conclusion3D printing of aortic annulus can offer reliable, not expensive patient-specific information to be used in the pre-operative planning of AVR or transcatheter aortic valve implantation (TAVI).     

Feasibility of C-arm computed tomography for transcatheter aortic valve replacement planning

BackgroundThe C-arm used for fluoroscopy during transcatheter aortic valve replacement (TAVR) may also be used to acquire 3-dimensional data sets similar to multidetector row CT (MDCT).ObjectiveThe aim of this study was to evaluate the feasibility of C-arm CT (CACT) for aortic annulus and root (AoA/R) measurements in TAVR planning compared with MDCT.MethodsTwenty patients who were studied for TAVR underwent MDCT and CACT. Two independent observers measured predicted perpendicular projection to annular plane, diameters of the aortic annulus, sinus of Valsalva, sinotubular junction and ascending aorta, distance of coronary ostia to annular plane, sinus of Valsalva height, and leaflet length. Correlation between MDCT and CACT and interobserver variability were analyzed.ResultsMDCT and CACT showed strong correlation for all the measurements of the AoA/R (r ranging from 0.62 to 0.94; P between <.001 and .042) and also for the predicted perpendicular projection (left/right anterior oblique: r = 0.96, P = .002; cranial/caudal: r = 0.83, P = .043). Interobserver variability analysis showed disagreement for the measurements of the aortic annulus structures with CACT (intraclass correlation coefficient [ICC], <0.25) but not for the rest of the variables (ICC between 0.47 and 0.97). MDCT showed no interobserver variability for all the measurements (ICC between 0.45 and 0.93).ConclusionsCACT showed strong correlation with MDCT for the measurement of all AoA/R structures. However, CACT showed also important interobserver variability for the assessment of the aortic annulus. Therefore, valve sizing may not be reliably performed on the basis of CACT measurements alone.     

Accuracy of predicted orthogonal projection angles for valve deployment during transcatheter aortic valve replacement

BackgroundMulti-detector computed tomography (MDCT) predicted orthogonal projection angles have been introduced to guide valve deployment during transcatheter aortic valve replacement (TAVR). Our aim was to investigate the accuracy of MDCT prediction methods versus actual angiographic deployment angles.MethodsRetrospective analysis of 2 currently used MDCT methods: manual multiplanar reformations (MR) and the semiautomatic optimal angle graph (OAG). Paired analysis was used to compare the 2-dimensional distributions and means.ResultsWe included 101 patients with a mean (±SD) age of 81 ± 9 years. The MR and OAG methods were used in 46 and 55 patients, respectively. A ≥5% change from the predicted MDCT range in left anterior oblique/right anterior oblique (LAO/RAO) and the cranial/caudal (CRA/CAU) angle occurred in 42% and 58% of patients, respectively. The mean predicted versus actual deployment angles were significantly different (CRA/CAU: -2.6 ± 11.5 vs. -7.6 ± 10.7, p < 0.001; RAO/LAO 8.1 ± 10.9 vs. 9.5 ± 10.6, p = 0.048; respectively). The MR method resulted in a more accurate CRA/CAU angle (CRA/CAU: -4.6 ± 11.1 vs. -6.5 ± 11.8, p = 0.139; RAO/LAO 7.4 ± 11.2 vs. 10.4 ± 11.2, p = 0.008; respectively), whereas the use of the OAG resulted in a more accurate RAO/LAO angle (CRA/CAU: -0.9 ± 10.8 vs. -9±11.2, p < 0.001; RAO/LAO 9.05 ± 10.6 vs. 8.5 ± 9.9, p = 0.458; respectively). For the entire cohort, the 2-dimensional distributions and means of the predicted versus the actual angles were significantly different from each other (p < 0.001). We repeated our analysis using both MDCT methods and demonstrated similar results with each method.ConclusionsCurrently used MDCT methods for TAVR implantation angles are significantly modified before actual valve deployment. Thus, further refinement of these prediction methods is required.     

Oversizing in transcatheter aortic valve replacement,a commonly used term but a poorly understood one: Dependency on definition and geometrical measurements

BackgroundIn transcatheter aortic valve replacement, prosthesis oversizing is essential to prevent paravalvular regurgitation. However, the estimated extent of oversizing strongly depends on the measurement used for annular sizing.PurposeThe aim was to investigate the influence of geometrical parameters for calculation of relative oversizing in transcatheter aortic valve replacement, reported as percentage in relation to the native annulus size, to standardize reporting.MethodsElectrocardiogram-gated cardiac dual-source CT data of 130 consecutive patients with severe aortic stenosis (mean age, 81 ± 8 years; 56 men; mean aortic valve area, 0.67 ± 0.18 cm²) were included. Aortic annulus dimensions were quantified by means of planimetry that yielded area and perimeter at the level of the basal attachment points of the aortic cusps during systole. Area- and perimeter-derived diameters were calculated as D_A = 2 × √(A/π) and D_P = P/π. Hypothetical prosthesis sizing was based on D_A (23-mm prosthesis for 19–22 mm; 26-mm prosthesis for 22–25 mm; 29-mm prosthesis for 25–28 mm). Relative oversizing for hypothetical prosthesis selection was calculated as percentage in relation to the native annulus size.ResultsMean annulus area was 492.12 ± 94.9 mm² and mean perimeter was 80.1 ± 7.6 mm. D_P was significantly larger than D_A (25.5 ± 2.4 mm vs 24.9 ± 2.4 mm; P < .001). Mean maximum diameter was 28.1 ± 3.0 mm and mean minimal diameter was 22.8 ± 2.4 mm. Calculated eccentricity index [EI = 1 − minimal diameter/maximum diameter)] was 0.19 ± 0.06. Difference between D_P and D_A correlated significantly with EI (r = 0.67; P < .001). Relative oversizing was 10.2% ± 3.8% and 21.6% ± 8.4% by D_A and area, and 7.8% ± 3.9% by both D_P and perimeter.ConclusionFor planimetric assessment of aortic annulus dimensions with CT, the percentage oversizing calculated strongly depends on the geometrical variable used for quantifying annular dimensions. Standardized nomenclature seems warranted for comparison of future studies.     

超声心动图在二尖瓣置换术后远期心功能不全病因诊断中的应用

 目的探索超声心动图在二尖瓣置换(MVR)术后远期心功能不全病因诊断中的作用。方法超声随访44例MVR患者术后3个月～13.5a,并根据手术的远期效果,分为心功能不全组(A组)和康复组(B组)。除注意人工瓣和自然瓣的病变外,还分析了这2组手术前后左房、左室内径及左室射血分数(EF)的差异。结果超声显示A组二尖瓣位单组或伴主动脉瓣位双组人工瓣异常5例,其它自然瓣明显病变11例。术后A组的左室内径明显大于B组(P＜0.05),EF值明显小于B组(P＜0.01)。超声心动图提供的信息为36.4％心功能不全代偿期和66.7％失代偿期患者诊断出了导致心功能障碍的主要原因。结论MVR手术前后超声检查对术后远期心功能不全的诊断具有实用价值。     

Computed tomography-based fat and muscle characteristics are associated with mortality after transcatheter aortic valve replacement

BackgroundComputed tomography (CT)-based fat and muscle measures are associated with outcome in large populations. We tested if muscle and fat characteristics are associated with long-term outcomes after TAVR.MethodsWe included 403 clinical CTs performed prior to TAVR at our center between 2008 and 2016, measuring area (cm²) and density (Hounsfield units, HU) of both psoas muscles (PM), subcutaneous adipose (SAT), and visceral adipose tissue (VAT). Area measures were indexed to height, log-transformed and both area and density were standardized for analysis. We assessed the association of each measure with all-cause mortality (adjusted for age, sex, body mass index (BMI), and the Society of Thoracic Surgeons (STS) risk score.ResultsOf the 403 individuals (83 ± 8 years; 52% female), 167 (41.4%) died during a median follow-up of 458 days (interquartile range IQR 297–840). Fat measures were feasible and rapid. Fat area was available in 242 (60%) patients with an adequate field of view. Individuals with the lowest PM area, SAT area or VAT area exhibited the highest hazard of mortality. In addition, greater SAT density was associated with a higher mortality hazard (adjusted HR per standard deviation increase in density = 1.35, 95%CI 1.10–1.67, P = 0.005).ConclusionRapid CT-based tissue characterization is feasible in patients referred for TAVR. Decreased PM area and increased SAT density are associated with long-term mortality after TAVR, even after accounting for age, sex, BMI, and STS score. Further studies are necessary to interrogate sex-specific relationships between CT tissue metrics and mortality and whether CT measures are incremental to well-established frailty metrics.     

Transcatheter mitral valve replacement in mitral annulus calcification – “The art of computer simulation”

There is considerable interest in transcatheter prosthetic valve treatment for mitral valve disease in high-risk individuals. Although the presence of mitral annular calcium (MAC) may provide an anchoring zone for such devices, results to date have been modest with reported technical failure rates approaching 30% in specialist centers. This in part relates to the risk of left ventricular outflow tract obstruction and device dislodgment but also to the lack of specific imaging guidelines to plan for such procedures. We present the use of finite element analysis and computer simulation based on cardiac CT in three patients with severe MAC in whom transcatheter devices were considered. In the first two cases, the computer simulations were performed after the clinical procedure and were concordant with the clinical outcome. For the third case, computer simulation was performed prior to the clinical procedure. This indicated unsuitability for transcatheter device deployment and a subsequent medical management was adopted. Overall, our initial results suggest that computer simulation may have the potential to improve patient selection for transcatheter mitral valve replacement in the presence of significant MAC.