Feasibility of a High-Pitch Protocol for Transcatheter Aortic Valve Replacement Evaluation in Patients not Suitable for ECG-Gated CT

doi:10.21203/rs.3.rs-123721/v1

Download PDF

Research Article

Feasibility of a High-Pitch Protocol for Transcatheter Aortic Valve Replacement Evaluation in Patients not Suitable for ECG-Gated CT

https://doi.org/10.21203/rs.3.rs-123721/v1

This work is licensed under a CC BY 4.0 License

Version 1

posted 28 Dec, 2020

You are reading this latest preprint version

High-Pitch CT for TAVR Evaluation in Patients not Suitable for ECG-Gating

The use of transcatheter aortic valve replacement (TAVR) has been established to be non-inferior to surgical aortic valve replacement (SAVR). As a result, in the United States, more patients now undergo TAVR than SAVR. It is recommended that preprocedural CT imaging for aortic valve evaluation and optimal sizing should include an ECG-gated scan of, at least, the aortic root. However, many patients suffer from concomitant tachyarrhythmias such as atrial fibrillation, which may seriously degrade the diagnostic accuracy of ECG-gated scans. The aim of the present study is to explore whether a high-pitch non-ECG-gated computed tomography angiography (CTA) of the entire aorta can render similar diagnostic preprocedural images as a standard ECG-gated scan. 108 patients were included. Objective image quality parameters such as image noise, CNR and SNR as well as subjective image quality analysis by two different readers were compared. The results showed a significant increase in image noise at the level of the aortic root with use of the high-pitch protocol (p = 0.001). Otherwise, our study revealed no significant differences in subjective and objective image quality. Diagnostic image quality was achieved in all patients without a record of inaccurate sizing in the surgical reports or subsequent patient histories.

Surgery

Nuclear Medicine & Medical Imaging

TAVR Evaluation

High-Pitch CT

transcatheter aortic valve replacement (TAVR)

surgical aortic valve replacement (SAVR)

Aortic stenosis (AS) is the most common acquired valve defect ¹. Technological enhancements and procedural simplification have increased the use of Transcatheter Aortic Valve Replacement (TAVR) to treat AS. As a result, in the United States, more patients now undergo TAVR than isolated surgical aortic valve replacement ². Candidates for this intervention undergo preprocedural contrast-enhanced computed tomography (CT) imaging for annular sizing to guide device selection and assessment of the peripheral access route ^3,4.

The latest recommendations for preprocedural CT issued by the Society of Cardiovascular Computed Tomography (SCCT) suggest that, at least, the aortic root should be imaged with electrocardiogram (ECG)-gated scans to limit motion artifacts ⁵. Image quality is best in patients with a slow and regular sinus rhythm ⁶. However, more than 9% of patients suffering from AS have concomitant atrial fibrillation (AF) ⁷, which is characterized by a high heart rate (HR) and HR variability ⁸. This and other cardiac arrhythmias (CA) may result in significant artifacts ^9,10 and impair diagnostic performance of CT imaging ¹¹. Beta-blockers to regulate heartbeat are, however, not recommended in AS because there is concern that antihypertensive treatment may result in hypotension and hemodynamic collapse ^9,12.

In patients with CA, current SCCT guidelines suggest ECG-editing for retrospective ECG-gating to reduce artifacts in these patients ⁵. Otherwise, there are no further or specific recommendations concerning this particular group of patients. In patients with severe tachyarrhythmias, ECG-gating is, however, often not possible. Still, these patients require preprocedural imaging to qualify for TAVR. Thus, the aim of this study was to evaluate image quality and diagnostic adequacy of preprocedural TAVR CT in patients in whom ECG-gating is not possible by using a high-pitch, non-ECG-gated protocol compared with a protocol using prospective ECG-gating.

Patient Characteristics

Patient characteristics are summarized in Table 1. There was no significant (n. s.) difference between the two groups with respect to BMI (p = 0.508), sex (p = 0.553), eGFR (p = 0.648), volume of CM administered (p = 0.707), and distribution of CM volumes administered (p = 0.785). Heart rate (HR) was significantly faster in Group B with 80.3 ± 17.1 bpm compared to 68.3 ± 11.0 bpm in Group A (p = < 0.001). Furthermore, significantly more patients in Group B had a medical record of chronic CA with 41/56 compared to 11/52 in Group A (p < 0.001). In the patients with CA, persistent AF was by far the most common in both groups with 6/52 in Group A and 19/56 in Group B. Patients in Group B were significantly older by a mean of 3.5 years (p = 0.009). Scan time was significantly shorter in Group B with 4.5 ± 0.3 s compared to 13.9 ± 1.25 s (p = < 0.001) in Group A. Even though median kilovoltage (kV) was 100 kV in both groups, the median test showed a statistically significant difference (p = < 0.001) in kV between both groups. This is explained by the difference in distribution (Group A: 100 kV (n = 51) and 120 kV (n = 1), Group B: 100 kV (n = 38), 120 kV (n = 12) and 135 kV (n = 6)).

Table 1

Demographic and imaging data of the patients included in the two groups. The Mann-Whitney U-test was used to test for statistically significant differences in age, scan time and administered volume of CM, Student’s t-test for statistically significant differences in BMI, HR, and eGFR, and the chi-squared test for statistically significant differences in sex distribution, the distribution of CM volume, and the distribution of patients with a history of chronic CA. The Median Test was used to test for statistically significant differences in median kV.
Parameter	Total	Group A	Group B	p-Value
Number of Patients	107	52	56	p-Value
Age (years)	82.0 ± 7.6	80.2 ± 6.9	83.5 ± 7.4	0.009
BMI (kg/m²)	26.6 ± 5.6	27.2 ± 6.0	26.0 ± 5.3	0.508 (n. s.)
Sex (♂/♀)	63/44	31/21	28/28	0.553 (n. s.)
HR (bpm)	74.8 ± 15.7	68.8 ± 11.0	80.3 ± 17.1	< 0.001
History of Chronic CA (yes/no)	48/60	11/41	41/15	< 0.001
eGFR (ml/min/1.73 m²)	58.5 ± 18.6	59.7 ± 17.8	57.7 ± 17.4	0.648 (n. s.)
Scan Time (s)	8.9 ± 4.8	13.9 ± 1.25	4.5 ± 0.3	< 0.001
Median Kilovoltage (kV)	100	100	100	< 0.001
CM Volume (ml)	101.7 ± 20.3	105.5 ± 17.6	100.7 ± 20.5	0.707 (n. s.)
CM Volume Distribution 60/80/100/120 ml	12/18/26/51	5/8/14/25	7/7/19/23	0.785 (n. s.)

Radiation Dose

Mean DLP in Group A was 790.90 ± 238.15 mGy*cm compared to a mean of 357.10 ± 200.25 mGy*cm in Group B. Using the methods described in other studies ^13–15 we calculated a mean E of 13.44 ± 4.05 mSv for Group A and 6.07 ± 3.40 mSv for Group B as well as a mean SSDE of 13.84 ± 2.94 mGy for Group A and 5.69 ± 2.27 mGy for Group B. Differences were statistically significant (p = < 0.001). Results are summarized in Table 2.

Table 2

Summary of dose parameters. The Mann-Whitney U-test was used to test for statistically significant differences. The high-pitch protocol requires significantly less dose compared to the standard protocol.
Parameter	Group A	Group B	p-Value
DLP (mGy*cm)	790.90 ± 238.15	357.10 ± 200.25	< 0.001
E (mSv)	13.44 ± 4.05	6.07 ± 3.40	< 0.001
SSDE (mGy)	13.84 ± 2.94	5.69 ± 2.27	< 0.001

Objective Image Analysis

The objective image quality scores are summarized in Table 3. Image noise at the level of the aortic root was significantly increased in Group B (p = 0.001). Accordingly, SNR and CNR at the level of the aortic root were significantly decreased in Group B (p = 0.002 and 0.003). Furthermore, attenuation value for background muscle at the level of the abdominal aorta was significantly decreased in Group B (p < 0.001). There were no further statistically significant differences between both groups.

Table 3

Summary of objective image quality parameters measured in the aortic root and the abdominal aorta. The Mann-Whitney U-test was used to test for statistically significant differences. The high-pitch protocol leads to significantly more image noise at the level of the aortic root.
Region	Parameter	Group A	Group B	p-Value
Aortic Root	Vessel (HU) Muscle (HU) Image Noise (SD) CNR SNR	464.23 43.53 34.43 12.22 13.48	471.88 42.15 43.20 9.95 10.92	0.934 (n. s.) 0.898 (n. s.) 0.001 0.003 0.002
Abdominal Aorta	Vessel (HU) Muscle (HU) Image Noise (SD) CNR SNR	449.05 49.95 44.49 8.97 10.09	437.00 31.49 44.68 9.08 9.78	0.645 (n. s.) < 0.001 0.620 (n. s.) 0.895 (n. s.) 0.540 (n. s.)

Subjective Image Analysis

The subjective image quality scores are summarized in Table 4. There were no statistically significant differences between both readers in either of the two groups. The κ_w value indicated substantial interrater agreement for all categories. Diagnostic image quality was achieved in all patients without a record of inaccurate sizing in the surgical report or subsequent patient history. Exemplary images of the aortic root are shown in Fig. 1.

Table 4

Summary of subjective image quality parameters assessed on a 4-point scale and compared for interrater agreement using Cohen's weighted kappa coefficient (κ_w). The Mann-Whitney U-test was used to test for statistically significant differences. Subjective image quality is comparable for the two CT protocols.
Region	Rater 1	Rater 2
Aortic Root Group A vs Group B p-value	1.53 ± 0.61 vs 1.40 ± 0.50 0.498 (n. s.)	1.47 ± 0.61 vs 1.50 ± 0.68 0.998 (n. s.)
κ_w Group A (p-value) κ_w Group B (p-value)	Substantial: 0.644 (0.002) Substantial: 0.741 (< 0.001)
Aortoiliac Pathway Group A vs Group B p-value	1.11 ± 0.46 vs 1.05 ± 0.22 0.932 (n. s.)	1.05 ± 0.23 vs 1.08 ± 0.27 0.662 (n. s.)
κ_w Group A (p-value) κ_w Group B (p-value)	Substantial: 0.787 (< 0.001) Substantial: 0.787 (< 0.001)

Cardiac arrhythmias are a frequent phenomenon in patients suffering from AS and substantially degrade CT image quality as inconsistent R-R intervals may result in stair-step artifacts or extensive blurring within a single axial slab ^9,16, which may make it necessary to repeat the CT scan or examine the patient with alternative imaging modalities ¹⁷. Some sources thus advise not to examine patients with AF on 16- or 64-slice CT scanners, reporting that diagnostic image quality is frequently not achieved in these patients ^9,17. As a result, patients with severe CA such as tachyarrhythmias including AF and/or HR variability/HR higher than 65 bpm have often been excluded from research trials of cardiac CT imaging ¹⁰. Therefore, we investigated the performance of a high-pitch non-ECG-gated protocol for preprocedural TAVR imaging in patients in whom ECG-gating was precluded based on the presence of severe CA at the time of CT planning compared to a group of patients with sinus rhythm imaged with prospective ECG-gating.

The findings of our study show that the non-ECG-gated high-pitch protocol is a feasible alternative to the ECG-gated protocol as both methods result in diagnostic images. This was achieved despite CA identified by ECG monitoring immediately before CT and a significantly higher proportion of patients with a medical record of chronic CA in the group examined with the non-ECG-gated high-pitch protocol. Nonetheless, the non-ECG-gated protocol does significantly increase image noise and decrease SNR and CNR in the aortic root. Notably, these changes in objective image quality parameters did not result in a significant difference in subjective image quality ratings for either reader. Furthermore, none of the examinations with either the high-pitch or ECG-gated protocol resulted in artifacts that significantly degraded assessment of the aortic root or aorta. Therefore, precise aortic annulus measurement was always possible in both groups with no report of inaccurate sizing in the surgeon’s report or subsequent patient history. Moreover, the high-pitch protocol resulted in a significantly lower radiation exposure by 55% compared to the ECG-gated protocol (from 13.44 mSv to 6.07 mSv). Dose reduction may appear secondary as TAVR is currently generally performed in an elderly population ¹⁸. Nevertheless, two recent clinical trials published in The New England Journal of Medicine in 2019 have established the non-inferiority of TAVR compared to SAVR in low-risk patients. In these trials, TAVR had a clear early safety benefit over SAVR in low-risk patients and was associated with faster discharge from hospital, faster recovery and fewer rehospitalizations ^2,19. This has set the stage for a new wave of TAVR indications in a younger patient populace. Furthermore, since patients will already receive a significant radiation dose from procedural fluoroscopy, the ALARA (“as-low-as-reasonably-achievable”) principle should be taken seriously.

An unexpected result of our analysis was that attenuation of background muscle at the level of the abdominal aorta was significantly lower in Group B compared to Group A. This might be explained by the statistically significantly older age of patients in Group B compared to Group A.

In interpreting these data, some alternatives should be considered. First, as an alternative to prospective ECG-gating, which is generally prone to artifacts in arrhythmic patients at the borders of the acquired slabs, retrospective ECG-gated CT acquisition allows image reconstruction at numerous points within the R-R cycle using online or offline ECG-editing tools offered by vendors of selected CT scanners ^9,20. Second, third-generation CT scanners with wide scan coverage along the patient Z-axis and 16-cm detector coverage enable prospective ECG-gated scanning of the entire heart within a single heartbeat. Therefore, as scans that require image acquisition during more than one cardiac cycle are inherently sensitive to CA regardless of whether prospective or retrospective ECG-gating is used, a volume CT scanner covering the entire heart in an axial snapshot may yield more robust images while at the same time allowing further dose reduction ²⁰. While the first alternative, namely retrospective ECG-gating, comes with an increase in radiation dose ²¹, the latter requires CT scanners that are not readily available. Nonetheless, a study performed by Annoni et al. in 2018 showed such state-of-the-art CT hardware to reduce potential artifacts in preprocedural TAVR imaging, even in patients with AF (n = 15/115) ²². However, the authors also acknowledged that their study population had a lower incidence of AF in comparison with previous studies, which might have influenced their results ²².

Our study has some limitations. Because our protocol acquired images without ECG-gating, the aortic root was imaged in a random phase of the cardiac cycle. However, multiple studies agree that the annulus is larger in systole, and thus annular measurement for TAVR is typically derived from mid-systolic images ²³. Nonetheless, as previously mentioned, we found no evidence of inaccurate sizing in surgical reports or subsequent patient histories in either of the two groups investigated.

In conclusion, the ungated high-pitch CT protocol allows accurate preprocedural assessment for TAVR with excellent subjective image quality in a patient population suffering from CA. Therefore, it is a feasible and dose-saving alternative in patients not suitable for ECG-gated CT imaging.

Study Population

A total of 108 patients suffering from AS who were referred from our cardiology department for preprocedural CT for TAVR over a period of 21 months were considered for inclusion in this retrospective study. These patients were categorized into two groups. Group A (n = 52) included patients with sinus rhythm at the time of CT planning who were examined with a prospective ECG-gated protocol. Group B (n = 56) included patients whose ECG signal indicated substantial tachyarrhythmia at the time of CT planning who were examined using a high-pitch non-ECG-gated protocol.

The institutional review board of Charité – University Medicine Berlin (Charité Ethics Committee) approved this study (EA4/140/17) and waived informed consent due to the retrospective data acquisition. This study was conducted in accordance with local laws and regulations, the Declaration of Helsinki and Good Clinical Practice.

CT Protocol

No premedication to control heart rate was added to the patient’s baseline medication before the CT scan.

All imaging was performed on an 80-detector-row CT scanner (Aquilion PRIME, Canon Medical Systems, Otawara, Japan) adapted from a previously used protocol ²¹. Scan parameters were as follows: temporal resolution of 175 ms using half-scan reconstruction, automated tube voltage selection (min = 100 kV in Group A and Group B, max = 120 kV in Group A and 100 kV in Group B), automated tube current modulation based on two scanned projection radiographs (ATCM, min = 40 mA, max = 600 mA, with selected image noise of pixel values in the reconstructed image serving as image quality reference parameter, 0.5 mm thickness, 0.5 mm increment, 40 × 0.5 collimation, 0.35 s rotation time, 512 × 512 matrix). Axial images were reconstructed from raw data using Canon's integrated adaptive iterative dose reduction (AIDR-3D) reconstruction algorithm with 0.5 mm slice thickness.

In Group A, images were acquired with a non-ECG-gated scan of the upper thoracic aperture at a pitch of 0.813, followed by a prospective ECG-gated acquisition of the heart at a pitch of 0.267 and a subsequent non-ECG-gated abdominal/pelvic scan with a pitch of 0.813 reconstructed as one volume as previously described ²¹. In Group B, a high pitch of 1.388 was set for the entire non-ECG-gated single acquisition of the entire aorta.

All patients were administered an intravenous contrast agent (CA) bolus of iomeprol (400 mg iodine/ml; Imeron-400 MCT, Bracco, Milan, Italy) followed by a 60-ml saline flush using an automatic power injector (Accutron CT-D, Medtron AG, Saarbrücken, Germany). The CA dose and administration rate were adjusted to the estimated glomerular filtration rate (eGFR) as follows: 60-ml CA bolus at a rate of 3.0 ml/s for eGFR < 35 ml/min/1.73 m², 80-ml bolus at 4.0 ml/s for eGFR of 35–45 ml/min/1.73 m², 100-ml CA bolus at 4.0 ml/s for eGFR of 46–60 ml/min/1.73 m², and 120-ml CA bolus at 4.0 ml/s for eGFR > 60 ml/min/1.73 m². CT acquisition was started automatically with a delay of 3 s after vessel attenuation in a region of interest (ROI) placed in the ascending thoracic aorta exceeded 200 Hounsfield units (HU).

After acquisition, Vital's Vitrea™ Advanced 6.2 TAVR software (Vital Images Inc., Minnetonka, USA) was used for TAVR evaluation including semiautomatic identification and measurement of the area of the aortic annulus valve plane.

Radiation Dose

Radiation dose exposure was estimated and compared using dose-length product (DLP) in mGy*cm, effective dose (E) in mSv, and size-specific dose estimates (SSDE) in mGy. DLP was recorded from an automatically generated protocol, based on the CT dose index (CTDI). E was calculated from DLP according to the method and conversion coefficients (k) presented in the European Guidelines on Quality Criteria for Computed Tomography ^13,14: we used a k of 0.017, which is the mean of the k of the chest (0.017 mSv/mGy*cm), abdomen (0.015 mSv/mGy*cm), and pelvis (0.019 mSv/mGy*cm), and the following formula: E = k ⋅ DLP. SSDE was calculated, as described in another study ¹⁵, by multiplying conversion coefficients as a function of the sum of the lateral and anteroposterior dimensions with CTDI.

Objective Image Analysis

For quantification of objective image quality, circular ROIs were placed in the aortic lumen and the closest adjacent muscle at two anatomical levels in axial images: 1) the aortic root and 2) the abdominal aorta just proximal to the aortic bifurcation. The following parameters were measured: a) CT attenuation number of the artery and b) image noise, defined as the SD of the CT attenuation number of the artery. The following parameters were calculated: c) signal-to-noise ratio (SNR), defined as mean attenuation of the artery divided by image noise of the CT attenuation value of the artery and d) contrast-to-noise ratio (CNR), defined as the difference between mean attenuation of the artery and mean attenuation of the closest adjacent muscle, divided by image noise of the CT attenuation value of the artery ^13,24−27. All aortic ROIs were drawn as large as possible while avoiding calcifications or metallic artifacts to exclude partial volume effects. Muscle ROIs were made the same size as the corresponding vessel ROIs.

Subjective Image Analysis

Subjective Image Analysis was performed according to a previously published manuscript ²¹. Two medical doctors with different levels of experience (rater 1: 15 years; rater 2: 3 years) rated image quality of the aortic root and the aortoiliac pathway with respect to the following features: 1) clear identification of the annulus plane; 2) clear depiction of valve leaflets; 3) arterial wall sharpness; and 4) conspicuity of arterial wall calcifications. Image quality was rated on a 4-point Likert scale (1: excellent, 2: good, 3: sufficient, 4: poor) to avoid a midway option. Image datasets of both groups were blindly evaluated in random order using a hanging protocol on RA1000 PACS (GE Healthcare, Waukesha, USA) with a preset CT Angio window (W: 600 L: 300 HU) and 1-mm slice thickness. Raters only used axial images for reading but were allowed to change window settings.

Statistical Analysis

All data were tested for normal distribution using the Shapiro-Wilk test. Differences in body mass index (BMI), heart rate (HR), and eGFR were tested for significance with an unpaired Student’s t-test. To compare the distribution of male and female patients, the distribution of CM volume, and the distribution of patients with a record of chronic CA a chi-squared test (χ²) was used. Differences in patient age, scan time, CM volume, radiation dose, artery attenuation, image noise, SNR, CNR, and subjective image quality scores between the two groups were tested for significance using the Mann-Whitney U-test. Differences in median kilovoltage (kV) were tested for significance using the median test. Interrater agreement of subjective image quality scores between the two readers was compared using Cohen's weighted kappa coefficient (κ_w). κ_w was interpreted as follows: 0.00–0.20: poor, 0.21–0.40: slight, 0.41–0.60: moderate, 0.61–0.80: substantial, and 0.81–1.00: almost perfect agreement ^28,29. A p-value below 0.05 was considered statistically significant. Values are presented as mean ± SD unless specified otherwise. SPSS (SPSS® Mac, v. 20.0; IBM Corp., New York, NY) was used for all statistical analyses.

Data availability

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

Author Contribution

Conceived and designed the study: S.S. and S.M.N. Data processing and extraction: S.S.; Data analysis: S. S. and S.M.N.; Drafting of the manuscript: S. S., N. L. B. and S.M.N.; Commented on the manuscript, suggested revisions of important intellectual content and approved the final version: S. S., K.K.B., N. L. B., J. L. V., B. H. and S.M.N.; Administrative and technical support: S.M.N. and B.H.

Competing Interests

B. H. has in the past received research grants for the Department of Radiology, Charité – Universitätsmedizin Berlin from the following companies and institutions: Abbott, AbbVie, Ablative Solutions, Accovion, Achaogen, Actelion Pharmaceuticals, ADIR, Advanced Sleep Research, Aesculap, AGO, Alexion Pharmaceuticals, Amgen, AO Foundation, Arbeitsgemeinschaft Internistische Onkologie, Arena Pharmaceuticals, ARMO BioSciences, art photonics, Astellas, AstraZeneca, B. Braun, BARD, Bayer, Berlin-Brandenburger Centrum für Regenerative Therapien, Berliner Krebsgesellschaft, BIOTRONIK, Bioven, Boehringer Ingelheim, Boston Biomedical, Bracco, BrainsGate, Bristol-Myers Squibb, Bundesministerium für Bildung und Forschung, Canon Medical Systems, Cascadian Therapeutics, Celgene, CellAct Pharma, Celldex Therapeutics, CeloNova Bio-Sciences, Charité Research Organisation, Chiltern, Clovis Oncology, Corvia Medical, Covance, Cubist Pharmaceuticals, Curevac, Curis, Daiichi Sankyō, DC Devices, Delcath Systems, Demira, DFG, Deutsche Krebshilfe, Deutsche Rheuma-Liga, Deutsche Stiftung für Herzforschung, DSM Nutritional Products, Dynavax Technologies, Eli Lilly and Company, Eisai, EORTC, Epizyme, Essex Pharma, EU Funding Programmes, Euroscreen, FIBREX Medical, Focused Ultrasound Surgery Foundation, Fraunhofer-Gesellschaft, Galena Biopharma, Galmed Pharmaceuticals, Ganymed Pharmaceuticals, GETNE, Genentech, Gilead Sciences, GlaxoSmithKline, Glycotope, Goethe-Universität Frankfurt am Main, Guerbet, Guidant Europe, Halozyme, Hewlett Packard, ICON, Idera Pharmaceuticals, Ignyta, Immunocore, Immunomedics, INC Research, Incyte, Innate Pharma, INSIGHTEC, inVentiv Health, iOMEDICO, Ionis Pharmaceuticals, Ipsen Pharma, IQVIA, ISA Pharmaceutical, ITM Solucin, Janssen Pharmaceutical, Kantar Health, Kartos Therapeutics, Karyopharm Therapeutics, Klinische Forschung Berlin-Mitte, Kite Pharma, lnspireMD, Land Berlin, Lion Biotechnology, LMU München, Lombard Medical, Loxo Oncology, LSK BioPartners, Lundbeck, Lux Biosciences, LYSARC, MacroGenics, MagForce, MedImmune, Medpace, MedPass International, Medtronic, Merck, Merrimack Pharmaceuticals, MeVis Medical Solutions, Millennium Pharmaceuticals, Mologen, MorphoSys, Monika Kutzner Stiftung Berlin, MSD, Neovacs, NewLink Genetics, Nexus Oncology, NIH, Novartis, Novocure, Nuvaira, Nuvisan, Ockham Oncology, OHIRC, Orion Corporation, Parexel, Perceptive, Pfizer, Pharmacyclics, PharmaCept, Pharmacyclics, PharmaMar, Philips, PIQUR Therapeutics, Pluristem Therapeutics, PPD, PneumRX, Portola Pharmaceuticals, PRA Health Sciences, Premier-Research, Provectus Biopharmaceuticals, PSI CRO, Pulmonx International, Quintiles, Regeneron Pharmaceuticals, Respicardia, Roche, Samsung, Sanofis, Seattle Genetics, Servier, SGS Life Science Services, Shire Human Genetic Therapies, Siemens, Silence Therapeutics, Spectranetics, Spectrum Pharmaceuticals, St. Jude Medical, Symphogen, Taiho Pharmaceutical, TauRx, Terumo Medical Corporation, Tesaro, TETEC, Teva, Theorem Clinical Research, Theradex, Threshold Pharmaceuticals, TNS Healthcare, UCB, Vertex Pharmaceuticals, Winicker Norimed, Wyeth Pharma, Xcovery and Zukunftsfond Berlin. S. M. N. has in the past received research grants from Bayer, Canon Medical Systems, Guerbet, and Teleflex Medical. The funding had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The remaining authors declare that they have no conflicts of interest and did not receive any funds. There are no patents, products in development, or marketed products to declare.

Masci, P. G., Dymarkowski, S. & Bogaert, J. Valvular heart disease: what does cardiovascular MRI add? Eur Radiol18, 197-208, doi:10.1007/s00330-007-0731-x (2008).
Mack, M. J. et al. Transcatheter Aortic-Valve Replacement with a Balloon-Expandable Valve in Low-Risk Patients. N Engl J Med380, 1695-1705, doi:10.1056/NEJMoa1814052 (2019).
Leon, M. B. et al. Transcatheter aortic-valve implantation for aortic stenosis in patients who cannot undergo surgery. N Engl J Med363, 1597-1607, doi:10.1056/NEJMoa1008232 (2010).
Ismail, T. F. et al. High-pitch versus conventional cardiovascular CT in patients being assessed for transcatheter aortic valve implantation: a real-world appraisal. Open Heart4, e000626, doi:10.1136/openhrt-2017-000626 (2017).
Blanke, P. et al. Computed Tomography Imaging in the Context of Transcatheter Aortic Valve Implantation (TAVI)/Transcatheter Aortic Valve Replacement (TAVR): An Expert Consensus Document of the Society of Cardiovascular Computed Tomography. JACC Cardiovasc Imaging12, 1-24, doi:10.1016/j.jcmg.2018.12.003 (2019).
Salgado, R. A. et al. Preprocedural CT evaluation of transcatheter aortic valve replacement: what the radiologist needs to know. Radiographics34, 1491-1514, doi:10.1148/rg.346125076 (2014).
Dahl, J. S. et al. Atrial fibrillation in severe aortic valve stenosis — Association with left ventricular left atrial remodeling. 4, 102-107 (2014).
Greve, A. M. et al. Prognostic importance of atrial fibrillation in asymptomatic aortic stenosis: the Simvastatin and Ezetimibe in Aortic Stenosis study. Int J Cardiol166, 72-76, doi:10.1016/j.ijcard.2011.09.064 (2013).
Min, J. K., Berman, D. S. & Leipsic, J. Multimodality imaging for transcatheter aortic valve replacement. (Springer Science & Business Media, 2013).
Mushtaq, S., Conte, E., Melotti, E. & Andreini, D. Coronary CT Angiography in Challenging Patients: High Heart Rate and Atrial Fibrillation. A Review. Acad Radiol26, 1544-1549, doi:10.1016/j.acra.2019.01.022 (2019).
Andreini, D. et al. Image quality and radiation dose of coronary CT angiography performed with whole-heart coverage CT scanner with intra-cycle motion correction algorithm in patients with atrial fibrillation. Eur Radiol28, 1383-1392, doi:10.1007/s00330-017-5131-2 (2018).
Kang, T. S. & Park, S. Antihypertensive Treatment in Severe Aortic Stenosis. J Cardiovasc Imaging26, 45-53, doi:10.4250/jcvi.2018.26.e9 (2018).
Wielandner, A. et al. Is ECG triggering for motion artefact reduction in dual-source CT angiography of the ascending aorta still required with high-pitch scanning? The role of ECG-gating in high-pitch dual-source CT of the ascending aorta. Br J Radiol89, 20160174, doi:10.1259/bjr.20160174 (2016).
Christner, J. A., Kofler, J. M. & McCollough, C. H. Estimating effective dose for CT using dose-length product compared with using organ doses: consequences of adopting International Commission on Radiological Protection publication 103 or dual-energy scanning. AJR Am J Roentgenol194, 881-889, doi:10.2214/ajr.09.3462 (2010).
American Association of Physicists in, M. Size-specific dose estimates (SSDE) in pediatric and adult body CT examinations. Task Group204 (2011).
Litmanovich, D. E. et al. Imaging in Transcatheter Aortic Valve Replacement (TAVR): role of the radiologist. Insights Imaging5, 123-145, doi:10.1007/s13244-013-0301-5 (2014).
Feuchtner, G. Imaging of cardiac valves by computed tomography. Scientifica (Cairo)2013, 270579, doi:10.1155/2013/270579 (2013).
Matsumoto, S. et al. CT imaging before transcatheter aortic valve implantation (TAVI) using variable helical pitch scanning and its diagnostic performance for coronary artery disease. Eur Radiol27, 1963-1970, doi:10.1007/s00330-016-4547-4 (2017).
Popma, J. J. et al. Transcatheter Aortic-Valve Replacement with a Self-Expanding Valve in Low-Risk Patients. N Engl J Med380, 1706-1715, doi:10.1056/NEJMoa1816885 (2019).
Dewey, M. Cardiac Ct. (Springer, 2014).
Shnayien, S. et al. Radiation Dose Reduction in Preprocedural CT Imaging for TAVI/TAVR Using a Novel 3-Phase Protocol: A Single Institution's Experience. Rofo, doi:10.1055/a-1150-7646 (2020).
Annoni, A. D. et al. CT angiography prior to TAVI procedure using third-generation scanner with wide volume coverage: feasibility, renal safety and diagnostic accuracy for coronary tree. Br J Radiol91, 20180196, doi:10.1259/bjr.20180196 (2018).
Murphy, D. T. et al. Dynamism of the aortic annulus: Effect of diastolic versus systolic CT annular measurements on device selection in transcatheter aortic valve replacement (TAVR). J Cardiovasc Comput Tomogr10, 37-43, doi:10.1016/j.jcct.2015.07.008 (2016).
Beitzke, D. et al. Computed tomography angiography of the carotid arteries at low kV settings: a prospective randomised trial assessing radiation dose and diagnostic confidence. Eur Radiol21, 2434-2444, doi:10.1007/s00330-011-2188-1 (2011).
Apfaltrer, P. et al. Radiation dose and image quality at high-pitch CT angiography of the aorta: intraindividual and interindividual comparisons with conventional CT angiography. AJR Am J Roentgenol199, 1402-1409, doi:10.2214/ajr.12.8652 (2012).
Asano, Y. et al. Utility of second-generation single-energy metal artifact reduction in helical lung computed tomography for patients with pulmonary arteriovenous malformation after coil embolization.
Wang, R. et al. Diagnostic accuracy of coronary CT angiography: comparison of filtered back projection and iterative reconstruction with different strengths. J Comput Assist Tomogr38, 179-184, doi:10.1097/rct.0000000000000005 (2014).
Mandrekar, J. N. Measures of interrater agreement. J Thorac Oncol6, 6-7, doi:10.1097/JTO.0b013e318200f983 (2011).
Landis, J. R. & Koch, G. G. The measurement of observer agreement for categorical data. Biometrics33, 159-174 (1977).

Download PDF

Version 1

posted 28 Dec, 2020

You are reading this latest preprint version

Feasibility of a High-Pitch Protocol for Transcatheter Aortic Valve Replacement Evaluation in Patients not Suitable for ECG-Gated CT

Status:

Version 1

Abstract

Figures

Introduction

Results

Patient Characteristics

Radiation Dose

Objective Image Analysis

Subjective Image Analysis

Discussion

Methods

Study Population

CT Protocol

Radiation Dose

Objective Image Analysis

Subjective Image Analysis

Statistical Analysis

Declarations

Data availability

Author Contribution

Competing Interests

References

Status:

Version 1