Practical determination of aortic valve calcium volume score on contrast-enhanced computed tomography prior to transcatheter aortic valve replacement and impact on paravalvular regurgitation: Elucidating optimal threshold cutoffs

3D Characterization of the Aortic Valve and Aortic Arch in Bicuspid Aortic Valve Patients

Patients with bicuspid aortic valve (BAV) commonly have associated aortic stenosis and aortopathy. The geometry of the aortic arch and BAV is not well defined quantitatively, which makes clinical classifications subjective or reliant on limited 2D measurements. The goal of this study was to characterize the 3D geometry of the aortic arch and BAV using objective and quantitative techniques. Pre-TAVR computed tomography angiogram (CTA) in patients with BAV and aortic stenosis (AS) were analyzed (n = 59) by assessing valve commissural angle, presence of a fused region, percent of fusion, and calcium volume. The ascending aorta and aortic arch were reconstructed from patient-specific imaging segmentation to generate a centerline and calculate maximum curvature and maximum area change for the ascending aorta and the descending aorta. Aortic valve commissural angle signified a bimodal distribution suggesting tricuspid-like (≤ 150°, 52.5% of patients) and bicuspid-like (> 150°, 47.5%) morphologies. Tricuspid like was further classified by partial (10.2%) or full (42.4%) fusion, and bicuspid like was further classified into valves with fused region (27.1%) or no fused region (20.3%). Qualitatively, the aortic arch was found to have complex patient-specific variations in its 3D shape with some showing extreme diameter changes and kinks. Quantitatively, subgroups were established using maximum curvature threshold of 0.04 and maximum area change of 30% independently for the ascending and descending aorta. These findings provide insight into the geometric structure of the aortic valve and aortic arch in patients presenting with BAV and AS where 3D characterization allows for quantitative classification of these complex anatomic structures.

Value of Post-/Pre-Procedural Aortic Regurgitation Ratio vs. Pre-Procedural Aortic Valve Calcium Score to Predict Moderate to Severe Paravalvular Leak Requiring Post-Dilation after Transcatheter Aortic Valve Implantation

BACKGROUND AND AIM

Tools that assist interventionists in selecting patients for post-dilation (PD) are needed. We aimed to assess whether pre-interventional aortic valve calcium (AVC) or the peri-interventional aortic regurgitation (ARI) ratio is a better predictor for a more than mild paravalvular leak (PVL) requiring PD after TAVI.

METHODS

Patients undergoing TAVI with available data on AVC derived from MSCTs and the ARI ratio derived from peri-interventional hemodynamic curves were studied. The main outcome was moderate-to-severe PVL requiring PD.

RESULTS

In 237 patients, more than mild PVL after valve deployment was present in 25.7%. PD was performed in 65 patients. The median (IQR) total AVC was 390.5 (211.5-665.4) mm3. All calcification values were significantly higher in patients who underwent PD. The median (IQR) individual threshold was 600 (550-685) Hus. The overall ARI ratio was 0.78 (0.61-0.96), with values being significantly lower in patients who underwent PD: 0.61 (0.49-0.80) vs. 0.82 (0.69-0.99) (p < 0.001). Both the ARI ratio (OR [95%CI] 0.053 [0.014-0.203]; p < 0.001) and AVC (1.01 [1.000-1.002]; p = 0.015) predicted PD need. ROC curves showed higher discrimination for the ARI ratio (AUC 0.73) than for any calcification parameter (all AUCs ≤ 0.62).

CONCLUSIONS

The ARI ratio provides interventionists with a powerful predictive tool for PVL requiring PD after TAVI that is beyond the predictive value of pre-procedural valve calcification derived from MSCT.

A systematic review of contrast-enhanced computed tomography calcium scoring methodologies and impact of aortic valve calcium burden on TAVI clinical outcomes

Different methodologies have been used to assess the role of AV calcification (AVC) on TAVI outcomes. This systematic review aims to describe the burden of AVC, synthesize the different methods of calcium score quantification, and evaluate the impact of AVC on outcomes after TAVI. We included studies of TAVI patients who had reported AV calcium scoring by contrast-enhanced multidetector CT and the Agatston method. The impact of calcification on TAVI outcomes without restrictions on follow-up time or outcome type was evaluated. Results were reported descriptively, and a meta-analysis was conducted when feasible. Sixty-eight articles were included, with sample sizes ranging from 23 to 1425 patients. Contrast-enhanced calcium scoring was reported in 30 studies, calcium volume score in 28 studies, and unique scoring methods in two. All studies with calcium volume scores had variable protocols, but most utilized a modified Agatston method with variable attenuation threshold values of 300-850 HU. Eight studies used the Agatston method, with the overall mean AV calcium score in studies published from 2010 to 2012 of 3342.9 AU [95%CI: 3150.4; 3535.4, I2 ​= ​0%]. The overall mean score was lower and heterogenous in studies published from 2014 to 2020 (2658.9 AU [95% CI: 2517.3; 2800.5, I2 ​= ​79%]. Most studies reported a positive association between calcium burden and increased risk of adverse outcomes, including implantation of permanent pacemaker (7/8 studies), paravalvular leak (13/13 studies), and risk of aortic rupture (2/2 studies). AVC quantification methodology with contrast-enhanced CT is still variable. AVC negatively impacts TAVI outcomes independently of the quantification method.

A CT-based deep learning system for automatic assessment of aortic root morphology for TAVI planning

Accurate planning of transcatheter aortic valve implantation (TAVI) is important to minimize complications, and it requires anatomic evaluation of the aortic root (AR), commonly performed through 3D computed tomography (CT) image analysis. Currently, there is no standard automated solution for this process. Two convolutional neural networks with 3D U-Net architectures (model 1 and model 2) were trained on 310 CT scans for AR analysis. Model 1 performs AR segmentation and model 2 identifies the aortic annulus and sinotubular junction (STJ) contours. After training, the two models were integrated into a fully automated pipeline for geometric analysis of the AR. Results were validated against manual measurements of 178 TAVI candidates. The trained CNNs segmented the AR, annulus, and STJ effectively, resulting in mean Dice scores of 0.93 for the AR, and mean surface distances of 0.73 mm and 0.99 mm for the annulus and STJ, respectively. Automatic measurements were in good agreement with manual annotations, yielding annulus diameters that differed by 0.52 [-2.96, 4.00] mm (bias and 95% limits of agreement for manual minus algorithm). Evaluating the area-derived diameter, bias, and limits of agreement were 0.07 [-0.25, 0.39] mm. STJ and sinuses diameters computed by the automatic method yielded differences of 0.16 [-2.03, 2.34] and 0.1 [-2.93, 3.13] mm, respectively. The proposed tool is a fully automatic solution to quantify morphological biomarkers for pre-TAVI planning. The method was validated against manual annotation from clinical experts and showed to be quick and effective in assessing AR anatomy, with potential for time and cost savings.

Quantity and location of aortic valve calcification predicts paravalvular leakage after transcatheter aortic valve replacement: a systematic review and meta-analysis

Introduction

Transcatheter aortic valve replacement (TAVR) is the first-line treatment for patients with moderate-to-high surgical risk of severe aortic stenosis. Paravalvular leakage (PVL) is a serious complication of TAVR, and aortic valve calcification contributes to the occurrence of PVL. This study aimed to investigate the effect of location and quantity of calcification in the aortic valve complex (AVC) and left ventricular outflow tract (LVOT) on PVL after TAVR.

Method

We performed a systematic review and meta-analysis to evaluate the effect of quantity and location of aortic valve calcification on PVL after TAVR using observational studies from PubMed and EMBASE databases from inception to February 16, 2022.

Results

Twenty-four observational studies with 6,846 patients were included in the analysis. A high quantity of calcium was observed in 29.6% of the patients; they showed a higher risk of significant PVL. There was heterogeneity between studies (I2 = 15%). In the subgroup analysis, PVL after TAVR was associated with the quantity of aortic valve calcification, especially those located in the LVOT, valve leaflets, and the device landing zone. A high quantity of calcium was associated with PVL, regardless of expandable types or MDCT thresholds used. However, for valves with sealing skirt, the amount of calcium has no significant effect on the incidence of PVL.

Conclusion

Our study elucidated the effect of aortic valve calcification on PVL and showed that the quantity and location of aortic valve calcification can help predict PVL. Furthermore, our results provide a reference for the selection of MDCT thresholds before TAVR. We also showed that balloon-expandable valves may not be effective in patients with high calcification, and valves with sealing skirts instead of those without sealing skirts should be applied more to prevent PVL from happening.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=354630, identifier: CRD42022354630.

Anatomical morphology of the aortic valve in Chinese aortic stenosis patients and clinical results after downsize strategy of transcatheter aortic valve replacement

BACKGROUND

The study aimed to describe the aortic valve morphology in Chinese patients underwent transcatheter aortic valve replacement (TAVR) for symptomatic severe aortic stenosis (AS), and the impact of sizing strategies and related procedural outcomes.

METHODS

Patients with severe AS who underwent TAVR were consecutively enrolled from 2012 to 2019. The anatomy and morphology of the aortic root were assessed. "Downsize" strategy was preformed when patients had complex morphology. The clinical outcomes of patients who performed downsize strategy were compared with those received annular sizing strategy. The primary outcome was device success rate, and secondary outcomes included Valve Academic Research Consortium-3 clinical outcomes variables based on 1-year follow-up.

RESULTS

A total of 293 patients were enrolled. Among them, 95 patients (32.4%) had bicuspid aortic valve. The calcium volume (Hounsfield Unit-850) of aortic root was 449.90 (243.15-782.15) mm 3 . Calcium is distributed mostly on the leaflet level. Downsize strategy was performed in 204 patients (69.6%). Compared with the patients who performed annular sizing strategy, those received downsize strategy achieved a similar device success rate (82.0% [73] vs . 83.3% [170], P  = 0.79). Aortic valve gradients (downsize strategy group vs . annular sizing group, 11.28 mmHg vs. 11.88 mmHg, P  = 0.64) and percentages of patients with moderate or severe paravalvular regurgitation 2.0% (4/204) vs . 4.5% (4/89), P  = 0.21) were similar in the two groups at 30 days after TAVR. These echocardiographic results were sustainable for one year.

CONCLUSIONS

Chinese TAVR patients have more prevalent bicuspid morphology and large calcium volume of aortic root. Calcium is distributed mostly on the leaflet level. Compare with annular sizing strategy, downsize strategy provided a non-inferior device success rate and transcatheter heart valve hemodynamic performance in self-expanding TAVR procedure.

Aortic valve calcium volume as measured by native versus contrast-enhanced computer tomography and the implications for the diagnosis of severe aortic stenosis in TAVR patients with low-gradient aortic stenosis

Background

Most of TAVR centers evaluate the calcium score in contrast-enhanced (ce) CT. We compared in this study between different methodologies to measure calcium score. We studied also the difference between patients with low-gradient (LG) and high-gradient (HG) severe aortic stenosis (AS) as regard the burden of aortic valve calcium (AVC).

Results

We measured the calcium volume and score using Agatston methodology in non-contrast (nc) CT and with modified and fixed 850 Hounsfield unit (HU) thresholds in ce CT. The calcium score and volume in ceCT using even with modified thresholds is significantly lower than the assessed score and volume in ncCT. The median (IQR) of calcium score in nc CT and in cc CT were 1288 AU (750–1815) versus 947 HU (384–2202). The median (IQR) of calcium volume in nc CT and in cc CT with modified thresholds were 701 mm³ (239–1632) versus 197 mm³ (139–532). Agatston score and calcium volume were lower in patients with LG AS than HG AS; 2069 AU (899–2477) versus 928AU (572–1284) and 1537 mm³ (644–1860) versus 286 mm³ (160–700), respectively. Only 20% of patients with LGAS had Agatston score higher than the previously supposed AVC score threshold for the diagnosis of severe AS (> 2000AU in men and > 1200 in women).

Conclusions

The diagnosis of severe LGAS should not depend on a single parameter as calcium score. In these patients, calcium score should be measured in nc CT and not in ce CT.

Use of the SAPIEN 3 Transcatheter Heart Valve in High-Risk Scenarios

The transcatheter aortic valve replacement procedure is used in patients with aortic stenosis. Transcatheter aortic valve replacement devices are quite versatile; thus, they are increasingly being used for nonaortic applications, such as tricuspid valve-in-valve implantation. This case series describes a transcatheter aortic valve replacement procedure in 4 patients with anatomic challenges (eg, aortic tortuosity, high valvular calcium burden, highly calcified bicuspid valve, low coronary artery takeoff, left main coronary artery occlusion, and large aortic annulus) and a fifth patient who had a failed tricuspid bioprosthesis and underwent a tricuspid valve-in-valve implantation with the Edwards SAPIEN 3 transcatheter heart valve (Edwards Lifesciences). All procedures required adjustments to the standard protocol, and each procedure was successful. The critical, technical adjustments in the deployment technique and preprocedural planning of the procedures are detailed to provide a road map for other cardiologists who encounter similar challenges.

Calcium Load in the Aortic Valve, Aortic Root, and Left Ventricular Outflow Tract and the Risk for a Periprocedural Stroke

Background

Periprocedural stroke during transcatheter aortic valve implantation is a rare but devastating complication. The calcified aortic valve is the most likely source of the emboli in a periprocedural stroke. The total load and distribution of calcium in the leaflets, aortic root, and left ventricular outflow tract varies from patient to patient. Consequently, there could be patterns of calcification that are associated with a higher risk of stroke. This study aimed to explore whether the pattern of calcification in the left ventricular outflow tract, annulus, aortic valve, and ascending aorta can be used to predict a periprocedural stroke.

Methods

Among the 3282 consecutive patients who received a transcatheter aortic valve implantation in the native valve in Sweden from 2014 to 2018, we identified 52 who had a periprocedural stroke. From the same cohort, a control group of 52 patients was constructed by propensity score matching. Both groups had one missing cardiac computed tomography, and 51 stroke and 51 control patients were blindly reviewed by an experienced radiologist.

Results

The groups were well balanced in terms of demographics and procedural data. Of the 39 metrics created to describe calcium pattern, only one differed between the groups. The length of calcium protruding above the annulus was 10.6 mm (interquartile range 7-13.6) for patients without stroke and 8 mm (interquartile range 3-10) for stroke patients.

Conclusions

This study could not find any pattern of calcification that predisposes for a periprocedural stroke.

Three-year outcomes of transcatheter aortic valve implantation for bicuspid versus tricuspid aortic stenosis

BACKGROUND

Transcatheter aortic valve implantation (TAVI) might be a feasible treatment option for more patients with bicuspid aortic valve (BAV) stenosis. However, long-term follow-up data in this population are scarce.

AIMS

The aim of this study was to evaluate three-year outcomes after TAVI in patients with BAV.

METHODS

A total of 246 consecutive patients who underwent TAVI at a single centre in China between March 2013 and February 2018 were enrolled in this study. Clinical outcomes, health status and echocardiography were followed and recorded for three years.

RESULTS

Among 109 (44.3%) BAV patients, 61.5% were Type 0 and 36.7% were Type 1 BAV patients. BAV patients were younger (75 vs 77 years, p=0.041) and had a lower Society of Thoracic Surgeons (STS) score (5.09 vs 6.00, p=0.026) compared to tricuspid aortic valve (TAV) patients. There were no differences in three-year survival rates between bicuspid and tricuspid patients (87.1% vs 79.5%, log-rank p=0.126). Multivariate Cox regression analysis adjusting for confounding factors revealed a similar risk of all-cause mortality in the BAV population (hazard ratio [HR] 0.86, 95% confidence interval [CI]: 0.44-1.70, p=0.666). Except for the rate of permanent pacemaker implantation that was lower in BAV patients (11.9% vs 21.9%, p=0.041), the incidence of other clinical adverse events was comparable between the two groups. Both BAV and TAV patients showed an obvious improvement in valve haemodynamics, which was sustained for three years. In addition, similar left ventricular reverse remodelling was found during follow-up.

CONCLUSIONS

BAV patients showed similar satisfactory three-year clinical outcomes, persistent valve haemodynamics improvement, and obvious cardiac reverse remodelling after TAVI compared to TAV patients.

Models and Techniques to Study Aortic Valve Calcification in Vitro, ex Vivo and in Vivo. An Overview

Aortic valve stenosis secondary to aortic valve calcification is the most common valve disease in the Western world. Calcification is a result of pathological proliferation and osteogenic differentiation of resident valve interstitial cells. To develop non-surgical treatments, the molecular and cellular mechanisms of pathological calcification must be revealed. In the current overview, we present methods for evaluation of calcification in different ex vivo, in vitro and in vivo situations including imaging in patients. The latter include echocardiography, scanning with computed tomography and magnetic resonance imaging. Particular emphasis is on translational studies of calcific aortic valve stenosis with a special focus on cell culture using human primary cell cultures. Such models are widely used and suitable for screening of drugs against calcification. Animal models are presented, but there is no animal model that faithfully mimics human calcific aortic valve disease. A model of experimentally induced calcification in whole porcine aortic valve leaflets ex vivo is also included. Finally, miscellaneous methods and aspects of aortic valve calcification, such as, for instance, biomarkers are presented.

An Analytic Method for Calculating Scanner-, Kilovoltage Peak-, and Patient Size-Specific Hounsfield Unit Scale Thresholds for Agatston Score

OBJECTIVE

This study aimed to calculate scanner-, kilovoltage peak (kVp)-, and patient size-specific computed tomography (CT) number thresholds for determining Agatston score (AgSc).

METHODS

The proposed method was validated using calcium measurements in an anthropomorphic phantom for 4 CT scanners made by 4 vendors. The derived mass concentration (γ) thresholds were used to calculate kVp- and patient size-specific CT number thresholds. Two models were applied to reduce intrascanner and interscanner AgSc variation, respectively.

RESULTS

The mean error of the modeled CT numbers is 1.8% (0.1%-4.4%). Model 1 has comparable results to the published phantom calibration method for an average-size patient (error, 1.5%; 0.1%-5.1%). The size- and the kVp-dependent fitting of modeled results have R2 greater than 0.965.

CONCLUSIONS

Our results show a potential to enable accurate determination of AgSc under diverse conditions (eg, reduced tube potential) and are more easily applicable to different patient sizes than the phantom calibration method.

Mitral annular calcification and valvular dysfunction: multimodality imaging evaluation, grading, and management

Mitral annular calcification (MAC) refers to calcium deposition in the fibrous skeleton of the mitral valve. It has many cardiovascular associations, including mitral valve dysfunction, elevated cardiovascular risk, arrhythmias, and endocarditis. Echocardiography conventionally is the first-line imaging modality for anatomic assessment, and evaluation of mitral valve function. Cardiac computed tomography (CT) has demonstrated importance as an imaging modality for the evaluation and planning of related procedures. It also holds promise in quantitative grading of MAC. Currently, there is no universally accepted definition or classification system of MAC severity. We review the multimodality imaging evaluation of MAC and associated valvular dysfunction and propose a novel classification system based on qualitative and quantitative measurements derived from echocardiography and cardiac CT.

Surgical management of misdeployed transcatheter aortic valve due to eccentric leaflet calcification

A serious complication of transcatheter valves is the mechanistic failure of the deployment system and prosthesis migration. We report the case of a transcatheter aortic valve implantation which failed during implantation resulting in dislodgement of the prosthesis. Emergency surgery to retrieve the deployment system and surgically replace the native valve was the only option to salvage the patient.

Advancements in Transcatheter Aortic Valve Implantation: A Focused Update

Transcatheter aortic valve implantation (TAVI) has become the leading technique for aortic valve replacement in symptomatic patients with severe aortic stenosis with conventional surgical aortic valve replacement (SAVR) now limited to patients younger than 65-75 years due to a combination of unsuitable anatomies (calcified raphae in bicuspid valves, coexistent aneurysm of the ascending aorta) and concerns on the absence of long-term data on TAVI durability. This incredible rise is linked to technological evolutions combined with increased operator experience, which led to procedural refinements and, accordingly, to better outcomes. The article describes the main and newest technical improvements, allowing an extension of the indications (valve-in-valve procedures, intravascular lithotripsy for severely calcified iliac vessels), and a reduction of complications (stroke, pacemaker implantation, aortic regurgitation).

Estimation of Aortic Valve Calcium Score Based on Angiographic Phase Versus Reduction of Ionizing Radiation Dose in Computed Tomography

The aim of the study was to evaluate the estimation efficacy of aortic valve calcium score (AVCS) based on the multislice computed tomography (MSCT) angiographic phase. The evaluation of the reduced amount of ionizing radiation dose was performed because of this estimation. The study included 51 consecutive patients who qualified for transcatheter aortic valve implantation (TAVI) (78.59 ± 5.72 years). All subjects underwent MSCT: in the native phase dedicated to AVCS as well as angiographic phases aimed to morphologically assess the aortic ostium and arterial accesses for TAVI. Based on the native phase, an AVCS assessment was performed for axial reconstructions at 3.0 mm and 2.0 mm slice thickness (AVCS_native3.0 and AVCS_native2.0). Based on the angiographic phase AVCS was estimated for axial reconstruction at 0.6 mm slice thickness with increased values of lesion density in aortic valve cusps/aortic valve annulus, which is considered a calcification, from a typical value of 130 HU to 500 HU and 600 HU (AVCS_{CTA0.6 500 HU} and AVCS_{CTA0.6 600 HU}). Mathematical formulations were developed, allowing for AVCS native calculation based on AVCS values estimated based on the angiographic phase: AVCS_native3.0 = 813.920 + 1.510 AVCS_{CTA0.6 500 HU}; AVCS_native3.0 = 1235.863 + 1.817 AVCS_{CTA0.6 600 HU}; AVCS_native2.0 = 797.471 + 1.393 AVCS_{CTA0.6 500 HU}; AVCS_native2.0 = 1228.310 + 1.650 AVCS_{CTA0.6 600 HU}. The amount of a potential reduction in dose length product (DLP) in the case of AVCS estimation was 4.45 ± 1.54%. In summary, relying solely on the angiographic phase of MSCT examination before TAVI, it is possible to conclusively estimate AVCS. This estimation results in a marked reduction in radiation dose in MSCT.

Threshold for calcium volume evaluation in patients with aortic valve stenosis: correlation with Agatston score

BACKGROUND

The evaluation of aortic valve calcium burden is important when planning for transcatheter aortic valve implantation (TAVI). Although a robust golden standard methodology is available for calcium evaluation on noncontrast-enhanced (NCE) computed tomographic (CT) series, a standard reference for calcium assessment on contrast-enhanced CT series is currently lacking.

METHODS

Two hundred and forty-four preprocedural CT scans from patients who had received TAVI were analysed. We correlated the aortic calcium volumes obtained on CE series at three thresholds [450, 850, and 'probe + 100' Hounsfield Units (HU)] with the Agatston score obtained on NCE scans. A subgroup analysis was performed taking into account the contrast enhancement of the left ventricular outflow tract (LVOT), with a prespecified cut-off of 300 HU.

RESULTS

The overall population analysis showed higher correlation with the Agatston score using the 850 HU threshold (r = 0.45, P < 0.0001); no correlation was found with the 450 HU threshold, whilst the 'probe + 100' HU threshold showed a weaker correlation (r = 0.30, P < 0.0001). In patients with LVOT enhancement less than 300 HU, 450 HU showed the highest accuracy in calcium identification (r = 0.70, P < 0.0001), whereas in patients with LVOT enhancement of at least 300 HU, the most accurate threshold was 850 HU (r = 0.46, P < 0.0001).

CONCLUSION

The thresholds for correct calcium identification using the automatic 3Mensio software depend on the contrast enhancement of aortic and cardiac structures, which can be estimated by measuring the HU in the LVOT. In patients with LVOT HU of less than 300, the correct threshold to be set in the software is 450 HU, whereas in patients with LVOT HU of at least 300 the correct threshold is 850 HU.

Does Aortic Valve Calcium Score Still Predict Death, Cardiovascular Outcomes, and Conductive Disturbances after Transcatheter Aortic Valve Replacement with New-Generation Prostheses?

Background

The development of transcatheter aortic valve replacement (TAVR) has led to an improvement in morbidity-mortality in the treatment of severe aortic stenosis in patients at high surgical risk. However, the procedure is not free from life-threatening cardiovascular outcomes and conductive disturbances. The objective of our study was to analyze the prognostic impact of aortic valve calcium score on the occurrence of complications following the procedure.

Materials and Methods

Patients who have benefited from TAVR with the implantation of new-generation Sapien 3 and Evolut R aortic valve prostheses between January 2017 and July 2018 with the prior realization of a cardiac computed tomography with measurement of the aortic valve calcium score were retrospectively analyzed. Primary endpoint was a composite of death, stroke, and myocardial infarction within a period of 1 month after TAVR. Relation between valvular calcium and conductive disturbances was secondarily analyzed over the same period, and occurrences of high-degree atrioventricular block (paroxysmal or permanent), new-onset left bundle branch block, and the need for permanent or transient cardiac stimulation were associated with the secondary endpoint.

Results

Overall, 144 patients were included. The aortic valve calcium score was not significantly higher in patients who reached the primary endpoint (2936 ± 1235 vs. 3051 ± 1440, P = 0.93). Among the 106 patients analyzed after excluding subjects with a prior pacemaker or left bundle branch block, aortic valvular calcium score was not statistically associated with the occurrence of conduction disturbances (3210 ± 1436 vs. 2948 ± 1223, P = 0.31).

Conclusion

Our results suggest that the measurement of aortic valve calcium score has no prognostic value regarding mortality, cardiovascular events, or conductive disturbances after TAVR using the new generation of valves.

Multimodality Imaging for Discordant Low-Gradient Aortic Stenosis: Assessing the Valve and the Myocardium

Aortic stenosis (AS) is a disease of the valve and the myocardium. A correct assessment of the valve disease severity is key to define the need for aortic valve replacement (AVR), but a better understanding of the myocardial consequences of the increased afterload is paramount to optimize the timing of the intervention. Transthoracic echocardiography remains the cornerstone of AS assessment, as it is universally available, and it allows a comprehensive structural and hemodynamic evaluation of both the aortic valve and the rest of the heart. However, it may not be sufficient as a significant proportion of patients with severe AS presents with discordant grading (i.e., an AVA ≤ 1 cm² and a mean gradient <40 mmHg) which raises uncertainty about the true severity of AS and the need for AVR. Several imaging modalities (transesophageal or stress echocardiography, computed tomography, cardiovascular magnetic resonance, positron emission tomography) exist that allow a detailed assessment of the stenotic aortic valve and the myocardial remodeling response. This review aims to provide an updated overview of these multimodality imaging techniques and seeks to highlight a practical approach to help clinical decision making in the challenging group of patients with discordant low-gradient AS.

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

BACKGROUND

Mitral 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.

METHODS

Consecutive 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.

RESULTS

MCV >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.

CONCLUSIONS

Calcification 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 REGISTRATION

NCT01368250.

Association of Time Between Left Ventricular and Aortic Systolic Pressure Peaks With Severity of Aortic Stenosis and Calcification of Aortic Valve

Importance

Diagnosis of low-gradient severe aortic stenosis (AS) is challenging. We hypothesized that the time between left ventricular (LV) and aortic systolic pressure peaks (TLV-Ao) is associated with aortic stenosis (AS) severity and may have additive value in diagnosing severe AS, especially in patients with low-gradient AS.

Objective

To investigate the diagnostic utility of measuring catheter-based TLV-Ao in patients with severe AS.

Design, Setting, and Participants

We studied 123 patients with severe AS at the Cleveland Clinic Foundation, a tertiary referral center, who underwent transcatheter aortic valve replacement (TAVR) via femoral access and had pre-TAVR cardiac computed tomography assessment and hemodynamic measurements recorded during a TAVR procedure. All patients received hemodynamic evaluation, echocardiographic assessment, and quantification of aortic valve calcification (AVC) by multidetector computed tomography. Hemodynamic data were collected via left heart catheterization done just before TAVR, and TLV-Ao was calculated offline. Data were analyzed between October 5, 2015, and July 20, 2016.

Main Outcomes and Measures

The association between TLV-Ao and AVC or other conventional imaging parameters was analyzed.

Results

Of the included patients, the mean (SD) age was 81 (9) years, and 65 (54%) were men (54%). Among 123 patients, 48 patients (39%) had low-gradient AS (<40 mm Hg) and mean (SD) TLV-Ao was 69 (39) milliseconds. In multivariable logistic regression analyses, higher TLV-Ao (odds ratio [OR], 1.02; 95% CI, 1.01-1.04; P = .002) and higher peak aortic valve (AV) velocity (OR, 1.01; 95% CI, 1.00-1.02; P = .008) were independently associated with severe AVC (AVC >1000 AU). Adding TLV-Ao to the peak AV velocity and AV area showed significant incremental value to be associated with AVC, with a net reclassification improvement of 0.61 (95% CI, 0.23-0.99; P = .002) and integrated discriminatory improvement of 0.09 (95% CI, 0.03-0.16; P = .003). In a subgroup of patients with low-grade AS, higher TLV-Ao was the only parameter associated with severe AVC (OR, 1.02; 95% CI, 1.001-1.04; P = .03).

Conclusions and Relevance

Prolonged TLV-Ao was associated with severe AVC. This catheter-based hemodynamic index may be an additional surrogate to differentiate low-gradient true severe AS. Larger, prospective studies investigating the role of TLV-Ao as a marker of clinical outcomes in patients undergoing TAVR are required.

Why and How to Measure Aortic Valve Calcification in Patients With Aortic Stenosis

The first-line evaluation of aortic stenosis severity is Doppler echocardiography. However, in up to 40% of patients, resting echocardiographic assessment of aortic stenosis severity is discordant, leading to clinical uncertainty. Interest has therefore grown in aortic valve calcium scoring by multidetector computed tomography (CT-AVC) as an alternative load independent assessment of aortic stenosis severity. This paper will briefly review the pathophysiology of aortic stenosis and the crucial role that calcification plays in driving progressive obstruction of the valve. Subsequently, it will describe published reports that have investigated CT-AVC, validating this parameter against histology, and establishing its diagnostic accuracy versus echocardiography as well as its powerful independent prognostic capability. Finally, this review seeks to provide a practical guide about how best to acquire and interpret CT-AVC with a close focus on potential pitfalls and how these might be best avoided as this technique becomes more widely adopted in to clinical practice.

Optimal Attenuation Threshold for Quantifying CT Pulmonary Vascular Volume Ratio

Objective

To evaluate the effects of attenuation threshold on CT pulmonary vascular volume ratios in children and young adults with congenital heart disease, and to suggest an optimal attenuation threshold.

Materials and Methods

CT percentages of right pulmonary vascular volume were compared and correlated with percentages calculated from nuclear medicine right lung perfusion in 52 patients with congenital heart disease. The selected patients had undergone electrocardiography-synchronized cardiothoracic CT and lung perfusion scintigraphy within a 1-year interval, but not interim surgical or transcatheter intervention. The percentages of CT right pulmonary vascular volumes were calculated with fixed (80–600 Hounsfield units [HU]) and adaptive thresholds (average pulmonary artery enhancement [PA_avg] divided by 2.50, 2.00, 1.75, 1.63, 1.50, and 1.25). The optimal threshold exhibited the smallest mean difference, the lowest p-value in statistically significant paired comparisons, and the highest Pearson correlation coefficient.

Results

The PA_avg value was 529.5 ± 164.8 HU (range, 250.1–956.6 HU). Results showed that fixed thresholds in the range of 320–400 HU, and adaptive thresholds of PA_avg/1.75–1.50 were optimal for quantifying CT pulmonary vascular volume ratios. The optimal thresholds demonstrated a small mean difference of ≤ 5%, no significant difference (> 0.2 for fixed thresholds, and > 0.5 for adaptive thresholds), and a high correlation coefficient (0.93 for fixed thresholds, and 0.91 for adaptive thresholds).

Conclusion

The optimal fixed and adaptive thresholds for quantifying CT pulmonary vascular volume ratios appeared equally useful. However, when considering a wide range of PA_avg, application of optimal adaptive thresholds may be more suitable than fixed thresholds in actual clinical practice.

Impact of aortic valve calcification severity on device success after transcatheter aortic valve replacement

Aortic valvular calcium score (AVCS) can identify severe aortic stenosis (AS) and provide powerful prognostic information. In severe and symptomatic AS, patients can be referred for a transcatheter aortic valve replacement (TAVR). The aim of this study was to determine whether AVCS, measured on the preoperative contrast enhanced multislice computed tomography (MSCT), is associated with device success (DS), major adverse cardiac events (MACEs) and paravalvular leak (PVL) after TAVR. Three hundred and fifty-two consecutive patients who underwent TAVR with a preoperative standardised contrast enhanced MSCT were included in the study. Valvular calcification detection was defined by adding + 100 Hounsfield Unit (HU) to mean HU determined by a region of interest placed in the contrast enhanced ascending aorta. AVCS was then indexed to the aortic annulus surface (AVCSi). Endpoints were DS and 30-day MACE according to Valve Academic Research Consortium-2 consensus document, and moderate to severe PVL. DS was obtained for 305 patients. In multivariate analysis, AVCSi was negatively and independently associated with DS: OR = 0.99, 95% CI 0.99-0.99, p = 0.03. In the subgroup analysis, this association was particularly relevant with self-expanding prostheses [n = 151 (43%), p = 0.018] and in the cases of asymmetric calcium valvular distribution [n = 283 (80%), p 0.002]. There was no association between MACE and AVCS (p = 0.953) and AVCSi (p = 0.757). PVL was positively associated with AVCS (p < 0.001) and AVCSi (p < 0.001). In conclusion, in TAVR, AVCS, measured on preoperative contrast enhanced MSCT, is significantly associated with DS and PVL, but not with 30-day MACE. Its routine use could be relevant to appreciate success chances of TAVR.

Degree of valve calcification in patients undergoing transfemoral transcatheter aortic valve implantation with and without balloon aortic valvuloplasty: Findings from the multicenter EASE-IT TF registry

AIMS

We aimed to assess whether the level of aortic root calcification is associated with BAV performance/omission during transcatheter aortic valve implantation (TAVI), and to explore related outcomes.

METHODS AND RESULTS

EASE-IT TF was a prospective, observational, multicenter registry of patients undergoing TF-TAVI with the Edwards SAPIEN 3, with or without BAV predilation. Valvular calcification was quantified from pre-procedural multi-slice computed tomography images and compared between BAV and no BAV patients. Data for 178 patients (55 BAV; 123 no BAV) were analyzed. There were no significant differences between groups in terms of regional/leaflet sector calcification volumes, maximum asymmetry between the different leaflet sectors, or total calcification scores. Overall, a greater-than-average leaflet calcification volume was independently predictive of ≥mild PVL (OR: 5.116; 95% CI: 1.042-38.35) and the need for post-dilation (OR: 3.592; 95% CI: 1.173-12.14). The latter effect was abated in patients with BAV (OR: 1.837; 95% CI: 0.223-18.00) and intensified in those without BAV (OR: 5.575; 95% CI: 1.114-38.74). No other BAV-dependent effects of calcification on outcomes were observed.

CONCLUSIONS

In the majority of transfemoral valve implantations, calcification does not appear to be the main driving factor in the decision to perform/omit BAV. Predilation may be valuable for reducing post-dilation requirements in patients only with a greater degree of leaflet calcification.

Computed tomography predictors of mortality, stroke and conduction disturbances in women undergoing TAVR: A sub-analysis of the WIN-TAVI registry

BACKGROUND

Aortic valve calcification patterns were associated with short- and long-term outcomes in previous small observational datasets of patients undergoing transcatheter aortic valve implantation (TAVI). The specific impact of multi detector-row computed tomography (MDCT) findings on outcomes in women has not been reported. We sought to describe the associations between MDCT characteristics and clinical outcomes in a registry of 547 women undergoing TAVI.

METHODS

WIN-TAVI is the first all-female registry to study the safety and effectiveness of TAVI in women (n = 1019). Thirteen sites participated in the MDCT sub-study and contributed pre-TAVI MDCT studies in 547 consecutive subjects. All MDCT data were analyzed in an independent core lab blinded to clinical outcomes. Key measurements included number of valve leaflets, aortic annulus area and perimeter, left and right coronary artery height, aortic cusp calcium volume, commissural calcification and left ventricular outflow tract (LVOT) calcification. Calcium volume of the aortic valvular complex was quantified using a threshold relative to patient-specific contrast attenuation in the arterial blood pool. We examined univariate and multivariate associations between ECG-gated contrast MDCT characteristics and 1-year mortality or stroke, new pacemaker implantation and new onset atrial fibrillation (AF).

RESULTS

The CT sub-study sample had a mean age of 82.8 ± 6.3 years, mean logistic EuroSCORE of 17.8 ± 11.3%, and mean STS score of 8.2 ± 7.4%. Transfemoral access was used in 89.6% of patients. After multivariate adjustment, moderate or severe LVOT calcification was an independent predictor of 1-year mortality or stroke (HR = 1.91; 95% CI: 1.11-3.30; p = 0.02). Calcium volume in the right coronary cusp was an independent predictor of new pacemaker (HR = 1.18 per 100 m³ increment; p = 0.04), whereas calcium volume of the non-coronary cusp had a protective effect (HR = 0.78 per 100 mm³ increment; p = 0.004). Severe calcification of the non-coronary/right-coronary commissure was an independent predictor of new AF (HR = 5.1; p = 0.008).

CONCLUSION

Computed tomography provides important prognostic information in women undergoing TAVI. Moderate or severe LVOT calcification is associated to an almost two-fold increased risk of mortality or stroke at one year. Different calcification patterns of the aortic valve may predict diverse rhythm abnormalities.