Clinical implementation of coronary computed tomography angiography for routine detection of cardiac allograft vasculopathy in heart transplant patients.

Cardiac allograft vasculopathy (CAV) is an accelerated form of coronary artery disease that affects long-term outcomes in heart transplant (HTx) patients. We prospectively evaluated the feasibility of coronary computed tomography angiography (CCTA) for the detection of CAV during clinical implementation at our center. All consecutive HTx patients >4 years post-transplant were actively converted from myocardial perfusion imaging to CCTA for the annual assessment of CAV. Between February 2018 and May 2019, 129/172 (75%) HTx patients underwent a CCTA. Renal impairment (n = 21/43) was the most frequent reason for patients could not undergo CCTA. CCTA image quality was good-excellent in 118/129 (92%) patients, and the radiation dose was 2.1 (1.6-2.8) mSv. CCTA showed obstructive CAV in 19/129 (15%) patients. Thirteen (10%) patients underwent additional tests, of which 8 patients underwent coronary revascularization within 90 days of CCTA. After 1 year, 3 additional coronary angiograms were performed, resulting in one revascularization in a patient with known severe CAV who developed ventricular tachycardia. One myocardial infarction after coronary stenting and 2 non-cardiac deaths were observed. CCTA can be successfully implemented for routine detection of CAV with good image quality and low radiation dose. CCTA allows CAV evaluation with the limited need for additional invasive testing.

Undetectable High-Sensitivity Troponin T as a Gatekeeper for Coronary Computed Tomography Angiography in Patients Suspected of Acute Coronary Syndrome.

OBJECTIVES: The aim of this study was to characterize the safety and efficiency of a strategy employing the limit of detection (LoD) of high-sensitivity troponin T (hs-TnT) as a gatekeeper for coronary computed tomography angiography (CCTA) in suspected acute coronary syndrome (ACS) patients in the emergency department (ED). METHODS: We included suspected ACS patients who underwent CCTA and were evaluated with hs-TnT. Patients were categorized as below the LoD and at or above the LoD. The primary outcome was 30-day major adverse cardiac events (MACEs), defined as all-cause mortality, ACS, or coronary revascularization. RESULTS: The study population consisted of 177 patients (mean age 55 ± 10 years, 50.3% women), and 16 (9.0%) patients reached the primary outcome. None of the patients died, while 13 had an adjudicated diagnosis of ACS, and 3 underwent elective coronary revascularization. There were 77 patients (44%) with an hs-TnT value below the LoD (MACEs; n = 1 [1.3%]) and 100 (56%) with at or above the LoD levels (MACEs; n = 15 [15%]). None of 67 patients with an hs-TnT value below the LoD and <50% stenosis on CCTA experienced MACEs. Out of the 10 patients with an hs-TnT value below the LoD and ≥50% stenosis on CCTA, 1 patient underwent elective percutaneous coronary revascularization. In patients with an hs-TnT value at or above the LoD, 74 patients had <50% stenosis on CCTA, and 2 patients (3%) were diagnosed with myocardial infarction without obstructive coronary artery disease confirmed on invasive angiography. Thirteen (50%) patients with an hs-TnT value at or above the LoD and ≥50% stenosis on CCTA experienced MACEs (11 ACS and 2 elective percutaneous coronary revascularizations). CONCLUSION: Our findings support that implementing the LoD of hs-TnT as a gatekeeper may reduce the need for CCTA in suspected ACS patients in the ED.

HEART score improves efficiency of coronary computed tomography angiography in patients suspected of acute coronary syndrome in the emergency department.

AIMS: Coronary computed tomography angiography is increasingly employed in the emergency department for suspected acute coronary syndrome patients. The HEART score has been proposed for initial risk stratification in these patients. The aim of this study was to investigate the diagnostic value and efficiency of the HEART score before coronary computed tomography angiography. METHODS AND RESULTS: We included patients suspected of acute coronary syndrome who underwent coronary computed tomography angiography in the emergency department. Based on the HEART score, patients were stratified as low-risk (HEART≤3), intermediate-risk (HEART4-6) and high-risk (HEART≥7). We assessed coronary computed tomography angiography for the presence of significant coronary artery disease (>50% stenosis). The primary outcome, the level of major adverse cardiac events, was a composite endpoint of all-cause mortality, acute coronary syndrome or coronary revascularisation within 30 days. The study population consisted of 340 patients (mean age: 55.6±10.1 years, 44.7% women), major adverse cardiac events occurred in 45 (13.2%) patients. The incidence of major adverse cardiac events in patients stratified as low-risk (35.0%), intermediate-risk (56.8%) and high-risk (8.2%) was 3.4%, 12.4% and 60.7%, respectively. All four low-risk patients with major adverse cardiac events had a HEART score of three. An algorithm where coronary computed tomography angiography is reserved for patients with HEART 3-6 resulted in a sensitivity of 97.8%, specificity of 84.1%, negative predictive value of 99.6% and positive predictive value of 48.4%, while reducing the need for coronary computed tomography angiography by 22% (n=75). CONCLUSION: The predictive value of coronary computed tomography angiography for 30-day major adverse cardiac events in suspected acute coronary syndrome patients is good, and reserving coronary computed tomography angiography for HEART score 3-6 patients reduces the number of needed coronary computed tomography angiograms without affecting diagnostic accuracy.

Computed tomography image quality of aortic stents in patients with aortic coarctation: a multicentre evaluation.

BACKGROUND: Stents are commonly used to treat aortic coarctation. The objective of this study was to evaluate the post-implantation computed tomography (CT) image quality of different stent types used to treat aortic coarctation. METHODS: Adult and paediatric patients with stent-treated aortic coarctation who underwent contrast-enhanced CT were retrospectively included from three tertiary care centres. CT scans were subjectively scored for image quality using a 4-point scale (1 = unacceptable; 2 = poor; 3 = good; 4 = excellent). Furthermore, the amount of stent-induced blooming artefacts was measured as the percentage of the difference between outer and inner stent diameters over the outer stent diameter. RESULTS: A total of 35 children and 34 adults implanted with 71 stents of six different types were included. The most commonly used stent type was the Cheatham Platinum stent (52 stents, 73%). The subjective image quality of the Cheatham Platinum stents was moderate with a score of 2.0±0.8 (mean ± standard deviation) in children and 2.3±0.6 in adults. The image quality in patients with Formula stents was 2.3±1.2. The Cheatham Platinum stents induced 34-48% blooming, the Formula stents 44-55%. The image quality in patients with the less commonly used Atrium Advanta V12, IntraStent, AndraStent and Palmaz stents was scored 3 (good) to 4 (excellent) with less blooming. The electrocardiographic gating and tube voltage (kVp) did not affect image quality. CONCLUSIONS: There is a substantial variation in CT image quality and blooming artefacts for different stent types used to treat aortic coarctation.

Prevalence and severity of arterial calcifications in pseudoxanthoma elasticum (PXE) compared to hospital controls. Novel insights into the vascular phenotype of PXE.

BACKGROUND AND AIMS: Pseudoxanthoma elasticum (PXE) is a monogenetic disorder with progressive calcifications of the skin, the Bruch's membrane in the eyes and the arterial wall. Vascular disease is considered to be very prevalent, but the whole-body distribution of arterial calcifications in PXE is unknown. We aimed to systematically investigate arterial calcifications in PXE. METHODS: We included 104 PXE patients from the Dutch PXE cohort and 93 hospital controls. All subjects underwent full-body low-dose CT scans without contrast. To investigate the prevalence and severity of arterial calcification per arterial location, CT scans were scored using a reproducible semi-quantitative scale with four calcification categories (interobserver kappa 0.54-0.99). RESULTS: PXE patients (38/104 males) were 54 ± 13 years and controls (45/93 males) 54 ± 16 years old. Arterial calcifications were significantly more common in PXE patients in the intracranial internal carotid artery (75% vs. 44%), the arteries of the arms (20% vs. 3%), the femoral-popliteal arteries (74% vs. 44%) and the subpopliteal arteries (84% vs. 38%). In these arteries, calcification scores also indicated more severe calcification. No significant differences in prevalence of arterial calcification were observed in other arterial beds such as the coronary arteries (45% vs. 43%, p = 0.776), the carotid arteries (52% vs. 46%, p = 0.476) and the abdominal aorta (71% vs. 63%, p = 0.287). Analyses using patients younger than 55 years only, showed similar differences in prevalence of arterial calcifications between PXE patients and controls, with most pronounced calcifications in the arteries of the lower legs (67% vs. 8%). Similar patterns were observed in those without concomitant diabetes or renal dysfunction. CONCLUSIONS: In PXE, a vascular phenotype can be identified with a distribution of arterial calcifications that is clearly distinct from hospital controls and involves arterial calcifications in the legs, the intracranial internal carotid arteries and the arteries of the arms.

Quantification of aortic annulus in computed tomography angiography: Validation of a fully automatic methodology.

BACKGROUND: Automatic accurate measuring of the aortic annulus and determination of the optimal angulation of X-ray projection are important for the trans-catheter aortic valve replacement (TAVR) procedure. The objective of this study was to present a novel fully automatic methodology for the quantification of the aortic annulus in computed tomography angiography (CTA) images. METHODS: CTA datasets of 26 patients were analyzed retrospectively with the proposed methodology, which consists of a knowledge-based segmentation of the aortic root and detection of the orientation and size of the aortic annulus. The accuracy of the methodology was determined by comparing the automatically derived results with the reference standard obtained by semi-automatic delineation of the aortic root and manual definition of the annulus plane. RESULTS: The difference between the automatic annulus diameter and the reference standard by observer 1 was 0.2±1.0mm, with an inter-observer variability of 1.2±0.6mm. The Pearson correlation coefficient for the diameter was good (0.92 for observer 1). For the first time, a fully automatic tool to assess the optimal projection curves was presented and validated. The mean difference between the optimal projection curves calculated based on the automatically defined annulus plane and the reference standard was 6.4° in the cranial/caudal (CRA/CAU) direction. The mean computation time was short with around 60s per dataset. CONCLUSION: The new fully automatic and fast methodology described in this manuscript not only provided precise measurements about the aortic annulus size with results comparable to experienced observers, but also predicted optimal X-ray projection curves from CTA images.

Visual versus automated evaluation of chest computed tomography for the presence of chronic obstructive pulmonary disease.

BACKGROUND: Incidental CT findings may provide an opportunity for early detection of chronic obstructive pulmonary disease (COPD), which may prove important in CT-based lung cancer screening setting. We aimed to determine the diagnostic performance of human observers to visually evaluate COPD presence on CT images, in comparison to automated evaluation using quantitative CT measures. METHODS: This study was approved by the Dutch Ministry of Health and the institutional review board. All participants provided written informed consent. We studied 266 heavy smokers enrolled in a lung cancer screening trial. All subjects underwent volumetric inspiratory and expiratory chest computed tomography (CT). Pulmonary function testing was used as the reference standard for COPD. We evaluated the diagnostic performance of eight observers and one automated model based on quantitative CT measures. RESULTS: The prevalence of COPD in the study population was 44% (118/266), of whom 62% (73/118) had mild disease. The diagnostic accuracy was 74.1% in the automated evaluation, and ranged between 58.3% and 74.3% for the visual evaluation of CT images. The positive predictive value was 74.3% in the automated evaluation, and ranged between 52.9% and 74.7% for the visual evaluation. Interobserver variation was substantial, even within the subgroup of experienced observers. Agreement within observers yielded kappa values between 0.28 and 0.68, regardless of the level of expertise. The agreement between the observers and the automated CT model showed kappa values of 0.12-0.35. CONCLUSIONS: Visual evaluation of COPD presence on chest CT images provides at best modest accuracy and is associated with substantial interobserver variation. Automated evaluation of COPD subjects using quantitative CT measures appears superior to visual evaluation by human observers.