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).     

Prosthesis-patient mismatch defined by cardiac computed tomography versus echocardiography after transcatheter aortic valve replacement

BackgroundsEvaluation of prosthesis-patient mismatch (P-PM) after transcatheter aortic valve replacement (TAVR) by transthoracic echocardiography (TTE) has provided conflicting results regarding its impact on outcomes. Whether post-TAVR computed tomography angiography (CTA) evaluation of P-PM can improve our understanding is unknown. We aimed to evaluate the inter-modality (TTE vs. CTA) agreement, inter-valve platform (balloon-expanding valve [BEV] vs. self-expandable valve [SEV]) differences in P-PM severity, and outcomes related to P-PM after TAVR.MethodsWe analyzed patients with both CTA and TTE before and after TAVR. Indexed effective orifice area was calculated using two methods: TTE-derived left ventricular outflow tract (LVOT) area from measured diameter and post-TAVR CTA-measured area. Body size specific cut-offs for P-PM severity were used: for body mass index (BMI) ​< ​30 ​kg/m², moderate ​= ​0.66–0.85 ​cm²/m² and severe≤0.65 ​cm²/m²; for BMI ≥30 ​kg/m², moderate ​= ​0.56–0.70 ​cm²/m² and severe≤0.55 ​cm²/m².ResultsA total of 447 patients were included (median age, 83 years; 54% male). The prevalence of P-PM (moderate or severe) was lower with CTA vs. TTE (3.5% vs. 19.5%, p ​< ​0.001). The prevalence of P-PM measured by TTE was more common in BEV compared to SEV (p ​= ​0.002), while CTA assessment showed no difference in P-PM incidence and severity between TAVR platforms (p ​= ​0.40). In multivariable analysis, CTA-defined but not TTE-defined P-PM was associated with mortality after TAVR (HR:3.97; 95%CI,1.55–10.2; p ​= ​0.004). Both CTA-defined and TTE-defined P-PM were associated with the composite of death and heart failure rehospitalization.ConclusionAlthough post-TAVR CTA substantially downgraded the prevalence of P-PM compared to TTE, it identified a subset of patients with clinically relevant P-PM which associated with outcomes.     

Low dose contrast CT for transcatheter aortic valve replacement assessment: Results from the prospective SPECTACULAR study (spectral CT assessment prior to TAVR)

BackgroundComputed tomographic angiography (CTA) based planning for transcatheter aortic valve replacement (TAVR) is essential for reduction of periprocedural complications. Spectral CT based imaging provides several advantages, including better contrast/signal to noise ratio and increased soft tissue contrast, permitting better delineation of contrast filled structures at lower doses of iodinated contrast media. The aim of this prospective study was to assess the initial feasibility of a low dose iodinated contrast protocol, utilizing monoenergetic 40 keV reconstruction, using a dual-layer CT scanner (DLCT) for CTA in patients undergoing TAVR planning.Methods116 consecutive TAVR patients underwent a gated chest and a non-gated CTA of the abdomen and pelvis. 40 keV virtual monoenergetic images (VMI) were reconstructed and compared with conventional polychromatic images (CI). The proximal aorta and access vessels were scored for image quality by independent experienced cardiovascular imagers.ResultsProximal aortic image quality as assessed by signal to noise (SNR) and contrast to noise ratio (CNR), were significantly better with 40 keV VMI relative to CI (SNR 14.65 ± 7.37 vs 44.16 ± 22.39, p < 0.001; CNR 15.84 ± 9.93 vs 59.8 ± 40.83, p < 0.001). Aortic root dimensions were comparable between the two approaches with a bias towards higher measurements at 40 keV (Bland Altman). SNR and CNR in all access vessel segments at 40 keV were substantially better (p < 0.001 for all peripheral access vessel segments) with comparable image quality.Conclusion40 keV VMI with low dose contrast dose spectral imaging is feasible for comprehensive preprocedural evaluation of access vessels and measurements of aortic root dimensions in patients undergoing TAVR.     

CT measurement of femoral anteversion angle in patients with unilateral developmental hip dysplasia: A comparative study between 2D and 3D techniques

Objective

To compare the accuracy of 2D and 3D CT measurements of femoral anteversion angle, in pediatric patients with developmental hip dysplasia.

Baseline global longitudinal strain by computed tomography is associated with post transcatheter aortic valve replacement outcomes

BackgroundsSubclinical myocardial dysfunction detected by global longitudinal strain (GLS) using echocardiography is associated with poor outcomes in patients with severe aortic stenosis (AS) despite normal left ventricular ejection fraction (LVEF). Computed tomography angiography derived GLS (CTA-GLS) has recently shown to be feasible, however the prognostic value remains unclear in severe AS patients treated with transcatheter aortic valve replacement (TAVR).MethodsWe analyzed consecutive patients who underwent TAVR with pre-TAVR retrospective gated acquisition CTA study with adequate image quality covering the entire left ventricle. CTA-GLS analysis was performed using 2D CT-Cardiac Performance Analysis prototype software (TomTec GmbH). Kaplan-Meier and Cox regression analyses were performed to evaluate the association of baseline CTA-GLS with all-cause mortality and a composite outcome of all-cause death and hospitalization for heart failure after TAVR.ResultsA total of 223 patients were included (mean age 83.5 ± 6.8 years, 45.7% female, mean CTA-LVEF 50.7 ± 14.5%). During a median follow-up of 32 months, 81 all-cause deaths and 134 composite outcomes occurred. When compared to patients with normal LVEF (≥50%) and preserved CTA-GLS (≤-20.5%), patients with normal LVEF but reduced CTA-GLS (>-20.5%) had higher all-cause mortality (Chi-square 6.89, p = 0.032) and the risk of composite outcome (Chi-square 7.80, p = 0.020) which was no different than those with impaired LVEF. Reduced CTA-GLS was independently associated with all-cause mortality (HR 1.71, 95% CI 1.01–2.90, p = 0.049) and the risk of composite outcome (HR 1.51, 95% CI 1.01–2.25, p = 0.044) on multivariable Cox regression analysis.ConclusionsReduced CTA-GLS provides independent prognostic value above multiple clinical and echocardiographic characteristics.     

Comparison of coronary CT angiography-based and invasive coronary angiography-based quantitative flow ratio for functional assessment of coronary stenosis: A multicenter retrospective analysis

BackgroundThe aim of this study was to evaluate the diagnostic performance of coronary CT angiography (CTA)-based quantitative flow ratio (QFR), namely CT-QFR, and compare it with invasive coronary angiography (ICA)-based Murray law QFR (μQFR), using fractional flow reserve (FFR) as the reference standard.MethodsPatients who underwent coronary CTA, ICA and pressure wire-based FFR assessment within two months were retrospectively analyzed. CT-QFR and μQFR were computed in blinded fashion and compared with FFR, all applying the same cut-off value of ≤0.80 to identify hemodynamically significant stenosis.ResultsPaired comparison between CT-QFR and μQFR was performed in 191 vessels from 167 patients. Average FFR was 0.81 ?± ?0.10 and 42.4% vessels had an FFR ≤0.80. CT-QFR had a slightly lower correlation with FFR compared with μQFR, although statistically non-significant (r ?= ?0.87 versus 0.90, p ?= ?0.110). The vessel-level diagnostic performance of CT-QFR was slightly lower but without statistical significance than μQFR (AUC ?= ?0.94 versus 0.97, difference: ?0.03 [95%CI: ?0.00-0.06], p ?= ?0.095), and substantially higher than diameter stenosis by CTA (AUC difference: 0.17 [95%CI: ?0.10-0.23], p ?< ?0.001). The patient-level diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio for CT-QFR to identify FFR value ?≤ ?0.80 was 88%, 90%, 86%, 86%, 91%, 6.59 and 0.12, respectively. The diagnostic accuracy of CT-QFR was 84% in extensively calcified lesions, while in vessels with no or less calcification, CT-QFR showed a comparable diagnostic accuracy with μQFR (91% versus 92%, p ?= ?0.595). Intra- and inter-observer variability in CT-QFR analysis was ?0.00 ?± ?0.04 and 0.00 ?± ?0.04, respectively.ConclusionsPerformance in diagnosis of hemodynamically significant coronary stenosis by CT-QFR was slightly lower but without statistical significance than μQFR, and substantially higher than CTA-derived diameter stenosis. Extensively calcified lesions reduced the diagnostic accuracy of CT-QFR.     

Right ventricular dysfunction by computed tomography associates with outcomes in severe aortic stenosis patients undergoing transcatheter aortic valve replacement

BackgroundAlthough cardiac computed tomography angiography (CCTA) assessment of right ventricular dysfunction (RVD) is feasible, the incremental prognostic value remains uncertain in patients undergoing transcatheter aortic valve replacement (TAVR) evaluation. This study sought to determine the incremental clinical utility of RVD identification by CCTA while accounting for clinical and echocardiographic parameters.MethodsPatients who underwent multiphasic ECG-gated functional CCTA using dual-source system for routine TAVR planning were evaluated. Biphasic contrast protocol injection allowed for biventricular contrast enhancement. CCTA-based RVD was defined as right ventricular ejection fraction (RVEF) ?< ?50%. The association of CCTA-RVD with all-cause mortality and the composite outcome of death or heart failure hospitalization after TAVR was evaluated and examined for its incremental utility beyond clinical risk assessment and echocardiographic parameters.ResultsA total of 502 patients were included (median [IQR] age, 82 [77 to 87] years; 56% men) with a median follow-up of 22 [16 to 32] months. Importantly, 126 (25%) patients were identified as having RVD by CCTA that was not identified by echocardiography. CCTA-defined RVD predicted death and the composite outcome in both univariate analyses (HR for mortality, 2.15; 95% CI, 1.44–3.22; p ?< ?0.001; HR for composite outcome, 2.11; 95% CI, 1.48–3.01; p ?< ?0.001) and in multivariate models that included clinical risk factors and echocardiographic findings (HR for mortality, 1.74; 95% CI, 1.11–2.74; p ?= ?0.02; HR for composite outcome, 1.63; 95% CI, 1.09–2.44; p ?= ?0.02).ConclusionsFunctional CCTA assessment pre-TAVR correctly identified 25% of patients with RVD that was not evident on 2D echocardiography. The presence of RVD on CCTA independently associates with clinical outcomes post-TAVR.     

Impact of membranous septum length on pacemaker need with different transcatheter aortic valve replacement systems: The INTERSECT registry

BackgroundNew permanent pacemaker implantation (new-PPI) remains a compelling issue after Transcatheter Aortic Valve Replacement (TAVR). Previous studies reported the relationship between a short MS length and the new-PPI post-TAVR with a self-expanding THV. However, this relationship has not been investigated in different currently available THV. Therefore, the aim of this study was to investigate the association between membranous septum (MS)-length and new-PPI after TAVR with different Transcatheter Heart Valve (THV)-platforms.MethodsWe included patients with a successful TAVR-procedure and an analyzable pre-procedural multi-slice computed tomography. MS-length was measured using a standardized methodology. The primary endpoint was the need for new-PPI within 30 days after TAVR.ResultsIn total, 1811 patients were enrolled (median age 81.9 years [IQR 77.2–85.4], 54% male). PPI was required in 275 patients (15.2%) and included respectively 14.2%, 20.7% and 6.3% for Sapien3, Evolut and ACURATE-THV(p ?< ?0.01).Median MS-length was significantly shorter in patients with a new-PPI (3.7 ?mm [IQR 2.2–5.1] vs. 4.1 ?mm [IQR 2.8–6.0], p ?= ?<0.01). Shorter MS-length was a predictor for PPI in patients receiving a Sapien3 (OR 0.87 [95% CI 0.79–0.96], p ?= ?<0.01) and an Evolut-THV (OR 0.91 [95% CI 0.84–0.98], p ?= ?0.03), but not for an ACURATE-THV (OR 0.99 [95% CI 0.79–1.21], p ?= ?0.91). By multivariable analysis, first-degree atrioventricular-block (OR 2.01 [95% CI 1.35–3.00], p = <0.01), right bundle branch block (OR 8.33 [95% CI 5.21–13.33], p = <0.01), short MS-length (OR 0.89 [95% CI 0.83–0.97], p ?< ?0.01), annulus area (OR 1.003 [95% CI 1.001–1.005], p ?= ?0.04), NCC implantation depth (OR 1.13 [95% CI 1.07–1.19] and use of Evolut-THV(OR 1.54 [95% CI 1.03–2.27], p ?= ?0.04) were associated with new-PPI.ConclusionMS length was an independent predictor for PPI across different THV platforms, except for the ACURATE-THV. Based on our study observations within the total cohort, we identified 3 risk groups by MS length: MS length ≤3 ?mm defined a high-risk group for PPI (>20%), MS length 3–7 ?mm intermediate risk for PPI (10–20%) and MS length > 7 ?mm defined a low risk for PPI (<10%). Anatomy-tailored-THV-selection may mitigate the need for new-PPI in patients undergoing TAVR.