Importance of imaging-acquisition protocol and post-processing analysis for extracellular volume fraction assessment by computed tomography.

BACKGROUND: Computed tomography angiography (CTA) assessment of myocardial extracellular volume fraction (CT-ECV) is feasible, although the protocols for imaging acquisition and post-processing methodology have varied. We aimed to identify a pragmatic protocol for CT-ECV assessment encompassing both imaging acquisition and post-processing methodologies to facilitate its clinical implementation. METHODS: We evaluated consecutive patients with severe aortic stenosis undergoing evaluation for transcatheter aortic valve replacement (TAVR). Pre-contrast and 3-min-delayed CTA were obtained in systole using either helical prospective-ECG-triggered (high-pitch) or axial sequential-ECG-gated acquisition, adding to standard TAVR CTA protocol. Using a dedicated software for co-registration of CTA datasets, three methodologies for ECV measurement were evaluated: (1) mid-septum region of interest (Septal ECV), (2) averaged-global ECV (Global ECV) encompassing 16-AHA segments, and (3) average of septal and lateral segments (Averaged ECVsep and Averaged ECVlat). RESULTS: Among the 142 patients enrolled (median â€‹= â€‹81 years, 44% females), 8 were excluded due to significant imaging artifacts precluding Global ECV assessment. High-pitch scan mode was performed in 68 patients (48%). Suboptimal image quality for Global ECV assessment was associated with high-pitch scan mode (odds ratio: OR â€‹= â€‹2.26, p â€‹= â€‹0.036), along with the presence of intracardiac leads (OR â€‹= â€‹4.91, p â€‹= â€‹0.002), and BMI≥35 â€‹kg/m2 (OR â€‹= â€‹2.80, p â€‹= â€‹0.026). Septal ECV [median â€‹= â€‹29.4%] and Averaged ECVsep [29.0%] were similar (p â€‹= â€‹0.108), while Averaged ECVlat [27.5%] was lower than Averaged ECVsep (p â€‹< â€‹0.001), resulting in lower Global ECV [28.6%]. CONCLUSIONS: Myocardial CT-ECV assessment is feasible using a systolic sequential acquisition pre-contrast, and similar additional 3-min delayed scan. Septal ECV measurement provides similar values to Global ECV and is equally reproducible.

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

BACKGROUNDS: Evaluation 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. METHODS: We 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) â€‹< â€‹30 â€‹kg/m2, moderate â€‹= â€‹0.66-0.85 â€‹cm2/m2 and severe≤0.65 â€‹cm2/m2; for BMI ≥30 â€‹kg/m2, moderate â€‹= â€‹0.56-0.70 â€‹cm2/m2 and severe≤0.55 â€‹cm2/m2. RESULTS: A 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 â€‹< â€‹0.001). The prevalence of P-PM measured by TTE was more common in BEV compared to SEV (p â€‹= â€‹0.002), while CTA assessment showed no difference in P-PM incidence and severity between TAVR platforms (p â€‹= â€‹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 â€‹= â€‹0.004). Both CTA-defined and TTE-defined P-PM were associated with the composite of death and heart failure rehospitalization. CONCLUSION: Although 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.

Safety, Efficacy, and Dose Protocol of Metoprolol for Heart Rate Reduction in Pediatric Outpatients Undergoing Cardiac CT Angiography. / Segurança, Eficácia e Protocolo de Dose de Metoprolol para Redução de Frequência Cardíaca em Pacientes Pediátricos Externos que Passaram por Angiografia Cardíaca por TC.

BACKGROUND: Image quality and radiation dose are optimized with a slow, steady heart rate (HR) when imaging the coronary arteries during cardiac computed tomography angiography (CCTA). The safety, efficacy, and protocol for HR reduction with beta blocker medication is not well described in a pediatric patient population. OBJECTIVE: Provide a safe and efficient metoprolol dose protocol to be used in pediatric outpatients undergoing CCTA. METHODS: We conducted a retrospective review of all pediatric outpatients who received metoprolol during CCTA. Demographic and clinical characteristics were summarized and the average reduction in HR was estimated using a multivariate linear regression model. Images were evaluated on a 1-4 scale (1= optimal). RESULTS: Seventy-eight pediatric outpatients underwent a CCTA scan with the use of metoprolol. The median age was 13 years, median weight of 46 kg, and 36 (46%) were male. The median doses of metoprolol were 1.5 (IQR 1.1, 1.8) mg/kg and 0.4 (IQR 0.2, 0.7) mg/kg for oral and intravenous administrations, respectively. Procedural dose-length product was 57 (IQR 30, 119) mGy*cm. The average reduction in HR was 19 (IQR 12, 26) beats per minute, or 23%. No complications or adverse events were reported. CONCLUSION: Use of metoprolol in a pediatric outpatient setting for HR reduction prior to CCTA is safe and effective. A metoprolol dose protocol can be reproduced when a slower HR is needed, ensuring faster acquisition times, clear images, and associated reduction in radiation exposure in this population. (Arq Bras Cardiol. 2021; 116(1):100-105).

FUNDAMENTO: Qualidade de imagem e dose de radiação são otimizadas com uma frequência cardíaca (FC) lenta e estável na realização de imagens de artérias coronárias durante a angiografia cardíaca por tomografia computadorizada (CCTA, do inglês cardiac computed tomography angiography) A segurança, a eficácia e o protocolo para a redução da FC com medicamento betabloqueador ainda não foi bem descrita em uma população de pacientes pediátricos. OBJETIVO: Oferecer um protocolo de dose de metoprolol eficiente a ser usado em pacientes pediátricos externos durante a CCTA. MÉTODOS: Realizamos uma revisão retrospectiva de todos os pacientes pediátricos externos que receberam o metoprolol durante a CCTA. As características demográficas e clínicas foram resumidas e a redução média em FC foi estimada utilizando-se um modelo de regressão linear multivariada. As imagens foram avaliadas em uma escala de 1 a 4 (1= ideal). RESULTADOS: Um total de 78 pacientes externos passaram a uma CCTA com o uso de metoprolol. A média de idade foi de 13 anos, a média de peso foi de 46 kg, e 36 pacientes (46%) eram do sexo masculino. As doses médias de metoprolol foram 1,5 (IQR 1,1; 1,8) mg/kg, e 0,4 (IQR 0,2; 0,7) mg/kg para administrações orais e intravenosas, respectivamente. O produto dose-comprimento por exame foi de 57 (IQR 30, 119) mGy*cm. A redução média da FC foi 19 (IQR 12, 26) batimentos por minuto, ou 23%. Não foram relatadas complicações ou eventos adversos. CONCLUSÃO: O uso de metoprolol num cenário de pacientes pediátricos externos para redução da FC antes de uma CCTA é seguro e eficiente. Pode-se reproduzir um protocolo de dose de metoprolol quando for necessário atingir uma FC mais lenta, garantindo tempos de aquisição mais rápidos, imagens mais claras e redução na exposição à radiação nessa população. (Arq Bras Cardiol. 2021; 116(1):100-105).

Segurança, Eficácia e Protocolo de Dose de Metoprolol para Redução de Frequência Cardíaca em Pacientes Pediátricos Externos que Passaram por Angiografia Cardíaca por TC / Safety, Efficacy, and Dose Protocol of Metoprolol for Heart Rate Reduction in Pediatric Outpatients Undergoing Cardiac CT Angiography

Resumo Fundamento Qualidade de imagem e dose de radiação são otimizadas com uma frequência cardíaca (FC) lenta e estável na realização de imagens de artérias coronárias durante a angiografia cardíaca por tomografia computadorizada (CCTA, do inglês cardiac computed tomography angiography) A segurança, a eficácia e o protocolo para a redução da FC com medicamento betabloqueador ainda não foi bem descrita em uma população de pacientes pediátricos. Objetivo Oferecer um protocolo de dose de metoprolol eficiente a ser usado em pacientes pediátricos externos durante a CCTA. Métodos Realizamos uma revisão retrospectiva de todos os pacientes pediátricos externos que receberam o metoprolol durante a CCTA. As características demográficas e clínicas foram resumidas e a redução média em FC foi estimada utilizando-se um modelo de regressão linear multivariada. As imagens foram avaliadas em uma escala de 1 a 4 (1= ideal). Resultados Um total de 78 pacientes externos passaram a uma CCTA com o uso de metoprolol. A média de idade foi de 13 anos, a média de peso foi de 46 kg, e 36 pacientes (46%) eram do sexo masculino. As doses médias de metoprolol foram 1,5 (IQR 1,1; 1,8) mg/kg, e 0,4 (IQR 0,2; 0,7) mg/kg para administrações orais e intravenosas, respectivamente. O produto dose-comprimento por exame foi de 57 (IQR 30, 119) mGy*cm. A redução média da FC foi 19 (IQR 12, 26) batimentos por minuto, ou 23%. Não foram relatadas complicações ou eventos adversos. Conclusão O uso de metoprolol num cenário de pacientes pediátricos externos para redução da FC antes de uma CCTA é seguro e eficiente. Pode-se reproduzir um protocolo de dose de metoprolol quando for necessário atingir uma FC mais lenta, garantindo tempos de aquisição mais rápidos, imagens mais claras e redução na exposição à radiação nessa população. (Arq Bras Cardiol. 2021; 116(1):100-105)

Abstract Background Image quality and radiation dose are optimized with a slow, steady heart rate (HR) when imaging the coronary arteries during cardiac computed tomography angiography (CCTA). The safety, efficacy, and protocol for HR reduction with beta blocker medication is not well described in a pediatric patient population. Objective Provide a safe and efficient metoprolol dose protocol to be used in pediatric outpatients undergoing CCTA. Methods We conducted a retrospective review of all pediatric outpatients who received metoprolol during CCTA. Demographic and clinical characteristics were summarized and the average reduction in HR was estimated using a multivariate linear regression model. Images were evaluated on a 1-4 scale (1= optimal). Results Seventy-eight pediatric outpatients underwent a CCTA scan with the use of metoprolol. The median age was 13 years, median weight of 46 kg, and 36 (46%) were male. The median doses of metoprolol were 1.5 (IQR 1.1, 1.8) mg/kg and 0.4 (IQR 0.2, 0.7) mg/kg for oral and intravenous administrations, respectively. Procedural dose-length product was 57 (IQR 30, 119) mGy*cm. The average reduction in HR was 19 (IQR 12, 26) beats per minute, or 23%. No complications or adverse events were reported. Conclusion Use of metoprolol in a pediatric outpatient setting for HR reduction prior to CCTA is safe and effective. A metoprolol dose protocol can be reproduced when a slower HR is needed, ensuring faster acquisition times, clear images, and associated reduction in radiation exposure in this population. (Arq Bras Cardiol. 2021; 116(1):100-105)

Computed Tomographic Angiography-Derived Risk Factors for Vascular Complications in Percutaneous Transfemoral Transcatheter Aortic Valve Implantation.

Transfemoral aortic valve implantation (TAVI) has become a viable alternative to surgical valve implantation, particularly for higher risk patients; however, vascular complications (VCs) remain a concern in transfemoral TAVI. We aimed to determine clinical and computed tomographic angiography-derived risk factors associated with Valve Academic Research Consortium (VARC)-2 criteria VCs in patients who underwent TAVI. From 2011 to 2017, 481 patients underwent percutaneous transfemoral TAVI at the Minneapolis Heart Institute and were screened for procedural and postprocedural access-related VC according to VARC-2 criteria. Clinical and clinical and computed tomographic angiography-derived data were collected to establish risk factors for VC. A total of 99 (21%) patients had VARC-2 VCs. Closure device failure (CDF) occurred in 56 of 99 (57%), minor VCs in 37 of 99 (37%), and major VCs occurred in 6 of 99 (6%). Access site-related VCs were preceded by CDF in 18 of 43 (42%) patients and the risk of major/minor VCs was 14 times greater in patients who experienced closure complications. The incidence of CDF was higher in common femoral artery (CFA) access sites with circumferential vessel wall calcification of more than 90° (p = 0.02) and when skin-surface to CFA access-site distance at an optimal access angle of 45° exceeded 80 mm (p = 0.03). In conclusion, both the degree of circumferential CFA access site calcification and distance to skin surface at an optimal access angle may improve risk stratification of access planning in patients who underwent percutaneous transfemoral TAVI.

Accessory renal arteries: Prevalence in resistant hypertension and an important role in nonresponse to radiofrequency renal denervation.

OBJECTIVE: The aim of this study was to understand the role of accessory renal arteries in resistant hypertension, and to establish their role in nonresponse to radiofrequency renal denervation (RDN) procedures. BACKGROUND: Prior studies suggest a role for accessory renal arteries in hypertensive syndromes, and recent clinical trials of renal denervation report that these anomalies are highly prevalent in resistant hypertension. This study evaluated the relationships among resistant hypertension, accessory renal arteries, and the response to radiofrequency (RF) renal denervation. METHODS: Computed Tomography Angiography (CTA) and magnetic resonance imaging (MRI) scans from 58 patients with resistant hypertension undergoing RF renal denervation (RDN) were evaluated. Results were compared with CT scans in 57 healthy, normotensive subjects undergoing screening as possible renal transplant donors. All scans were carefully studied for accessory renal arteries, and were correlated with long term blood pressure reduction. RESULTS: Accessory renal arteries were markedly more prevalent in the hypertensive patients than normotensive renal donors (59% vs 32% respectively, p=0.004). RDN had an overall nonresponse rate of 29% (response rate 71%). Patients without accessory vessels had a borderline higher response rate to RDN than those with at least one accessory vessel (83% vs 62% respectively, p=0.076) and a higher RDN response than patients with untreated accessory arteries (83% vs 55%; p=0.040). For accessory renal arteries and nonresponse, the sensitivity was 76%, specificity 49%, with positive and negative predictive values 38% and 83% respectively. CONCLUSIONS: Accessory renal arteries were markedly over-represented in resistant hypertensives compared with healthy controls. While not all patients with accessory arteries were nonresponders, nonresponse was related to both the presence and non-treatment of accessory arteries. Addressing accessory renal arteries in future clinical trials may improve RDN therapeutic efficacy.

Cardiovascular imaging trends in congenital heart disease: a single center experience.

BACKGROUND: Cardiac magnetic resonance imaging (MRI) and CT are available in the recent era at many pediatric cardiac centers. OBJECTIVE: The aim was to provide a contemporary description of diagnostic imaging trends for definition of congenital heart disease (CHD). METHODS: Echocardiography, cardiac catheterization, cardiac MRI, and cardiac CT use in patients with congenital heart disease at a single institution was retrospectively recorded (2005-2012). Surgical procedures were recorded. Total and modality-specific rates were estimated by Poisson regression and compared. The median age, studies in patients aged >17 years, and referral diagnosis were tabulated for the last year of review. RESULTS: An average of 11,940 cardiovascular diagnostic tests was performed annually. The number of total studies, echocardiograms, catheterizations, and surgical procedures, did not change significantly across time. Echocardiography comprised 95% to 97% of all studies performed during each year of review. The use of cardiac MRI (2%) and cardiac CT (1%) increased linearly (P < .001), and the use of diagnostic catheterization decreased (0.7%; P = .0005). The median age was 3 years for echocardiography, 15 years for MRI, 11 years for CT, and 3 years for catheterization. The percentage of patients aged >17 years was 9% for echocardiography, 33% for cardiac MRI, 29% for cardiac CT, and 8% for catheterization. Most patients undergoing CT, MRI, and diagnostic catheterization had moderate or complex CHD. CONCLUSION: Cardiac CT is used increasingly in the recent era for evaluation of CHD. The increased use of both cardiac CT and cardiac MRI are temporally associated with a decrease in diagnostic cardiac catheterization.