Non-Invasive Assessment of Endothelial Shear Stress in Myocardial Bridges Using Coronary Computed Tomography Angiography.

Myocardial bridging (MB) is a segment of coronary arteries with an intramural course, typically spared from atherosclerosis, while the adjacent proximal segment is reported to be atherosclerosis-prone, a phenomenon contributed to local endothelial shear stress (ESS). We aimed to describe the ESS milieu in coronaries with MBs combining coronary computed tomography angiography with computational fluid dynamics and to investigate the association of atherosclerosis presence proximal to MBs with hemorheological characteristics. Patients (n = 36) were identified and 36 arteries with MBs (11 deep and 25 superficial) were analyzed. ESS did not fluctuate 5 mm proximally to MBs vs 5 mm within MBs (0.94 vs 1.06 Pa, p = .56). There was no difference when comparing ESS in the proximal versus mid versus distal MB segments (1.48 vs 1.37 vs 1.9 Pa, p = ns). In arteries with plaques (n = 12), no significant ESS variances were observed around the MB entrance, when analyzing all arteries (p = .81) and irrespective of morphological features of the bridged segment (deep MBs; p = .65, superficial MBs; p = .84). MBs are characterized by homogeneous, atheroprotective ESS, possibly explaining the absence of atherosclerosis within bridged segments. The interplay between ESS and atherosclerosis is potentially not different in arteries with MB compared with arteries without bridges.

Long-axial field-of-view PET/CT for the assessment of inflammation in calcified coronary artery plaques with [68 Ga]Ga-DOTA-TOC.

PURPOSE: Inflamed, prone-to-rupture coronary plaques are an important cause of myocardial infarction and their early identification is crucial. Atherosclerotic plaques are characterized by overexpression of the type-2 somatostatin receptor (SST2) in activated macrophages. SST2 ligand imaging (e.g. with [68 Ga]Ga-DOTA-TOC) has shown promise in detecting and quantifying the inflammatory activity within atherosclerotic plaques. However, the sensitivity of standard axial field of view (SAFOV) PET scanners may be suboptimal for imaging coronary arteries. Long-axial field of view (LAFOV) PET/CT scanners may help overcome this limitation. We aim to assess the ability of [68 Ga]Ga-DOTA-TOC LAFOV-PET/CT in detecting calcified, SST2 overexpressing coronary artery plaques. METHODS: In this retrospective study, 108 oncological patients underwent [68 Ga]Ga-DOTA-TOC PET/CT on a LAFOV system. [68 Ga]Ga-DOTA-TOC uptake and calcifications in the coronary arteries were evaluated visually and semi-quantitatively. Data on patients' cardiac risk factors and coronary artery calcium score were also collected. Patients were followed up for 21.5 ± 3.4 months. RESULTS: A total of 66 patients (61.1%) presented with calcified coronary artery plaques. Of these, 32 patients had increased [68 Ga]Ga-DOTA-TOC uptake in at least one coronary vessel (TBR: 1.65 ± 0.53). Patients with single-vessel calcifications showed statistically significantly lower uptake (SUVmax 1.10 ± 0.28) compared to patients with two- (SUVmax 1.31 ± 0.29, p < 0.01) or three-vessel calcifications (SUVmax 1.24 ± 0.33, p < 0.01). There was a correlation between coronary artery calcium score (CACS) and [68 Ga]Ga-DOTA-TOC uptake, especially in the LAD (p = 0.02). Stroke and all-cause death occurred more frequently in patients with increased [68 Ga]Ga-DOTA-TOC uptake (15.63% vs. 0%; p:0.001 and 21.88% vs. 6.58%; p: 0.04, respectively) during the follow-up period. CONCLUSION: [68 Ga]Ga-DOTA-TOC as a marker for the macrophage activity can reveal unknown cases of inflamed calcified coronary artery plaques using a LAFOV PET system. [68 Ga]Ga-DOTA-TOC uptake increased with the degree of calcification and correlated with higher risk of stroke and all-cause death. [68 Ga]Ga-DOTA-TOC LAFOV PET/CT may be useful to assess patients' cardiovascular risk.

Noninvasive Multimodality Imaging for the Assessment of Anomalous Coronary Artery.

PURPOSE OF REVIEW: Anomalous aortic origin of a coronary artery (AAOCA) is a rare congenital coronary anomaly with the potential to cause myocardial ischemia and adverse cardiac events. The presence of AAOCA anatomy itself does not necessarily implicate a need for revascularization. Therefore, the purpose of this review is to assess how noninvasive comprehensive anatomic- and physiologic evaluation may guide patient management. RECENT FINDINGS: The assessment of AAOCA includes an accurate description of the anomalous origin/vessel course including anatomical high-risk features such as a slit-like ostium, proximal narrowing, elliptic vessel shape, acute take-off angle, intramural course, and possible concomitant coronary atherosclerosis and hemodynamics. Various cardiac imaging modalities offer unique advantages and capabilities in visualizing these anatomical and functional aspects of AAOCA. This review explored the role of noninvasive multimodality imaging in the characterization of AAOCA by highlighting the strengths, limitations, and potential applications of the current different cardiac imaging methods, with a focus on the pathophysiology of myocardial ischemia and stress testing protocols.

Diagnostic performance of quantitative coronary artery disease assessment using computed tomography in patients with aortic stenosis undergoing transcatheter aortic-valve implantation.

BACKGROUND: Computed tomography angiography (CTA) is a cornerstone in the pre- transcatheter aortic valve replacement (TAVI) assessment. We evaluated the diagnostic performance of CTA and coronary artery calcium score (CACS) for CAD evaluation compared to invasive coronary angiography in a cohort of TAVI patients. METHODS: In consecutive TAVI patients without prior coronary revascularization and device implants, CAD was assessment by quantitative analysis in CTA. (a) Patients with non-evaluable segments were classified as obstructive CAD. (b) In patients with non-evaluable segments a CACS cut-off of 100 was applied for obstructive CAD. The reference standard was quantitative invasive coronary angiography (QCA, i.e. ≥ 50% stenosis). RESULTS: 100 consecutive patients were retrospectively included, age was 82.3 ± 6.5 years and 30% of patients had CAD. In 16% of the patients, adequate visualization of the entire coronary tree (all 16 segments) was possible with CTA, while 84% had at least one segment which was not evaluable for CAD analysis due to impaired image quality. On a per-patient analysis, where patients with low image quality were classified as CAD, CTA showed a sensitivity of 100% (95% CI 88.4-100.0), specificity of 11.4% (95% CI 5.1-21.3), PPV of 32.6% (95% CI 30.8-34.5), NPV of 100% and diagnostic accuracy of 38% (95% CI 28.5-48.3) for obstructive CAD. When applying a combined approach of CTA (in patients with good image quality) and CACS (in patients with low image quality), the sensitivity and NPV remained at 100% and obstructive CAD could be ruled out in 20% of the TAVI patients, versus 8% using CTA alone. CONCLUSION: In routinely acquired pre-TAVI CTA, the image quality was insufficient in a high proportion of patients for the assessment of the entire coronary artery tree. However, when adding CACS in patients with low image quality to quantitative CTA assessment in patients with good image quality, obstructive CAD could be ruled-out in 1/5 of the patients and may therefore constitute a strategy to streamline pre-procedural workup, and reduce risk, radiation and costs in selected TAVI patients without prior coronary revascularization or device implants.

Noninvasive assessment of clinically significant portal hypertension using ΔT1 of the liver and spleen and ECV of the spleen on routine Gd-EOB-DTPA liver MRI.

PURPOSE: To analyze the predictive value of ΔT1 of the liver and spleen as well as the extracellular volume fraction (ECV) of the spleen as noninvasive biomarkers for the determination of clinically significant portal hypertension (CSPH) on routine Gd-EOB-DTPA liver MRI. METHOD: 195 consecutive patients with known or suspected chronic liver disease from 9/2018 to 7/2019 with Gd-EOB-DTPA liver MRI and abdominal T1 mapping were retrospectively included. Based on the presence of splenomegaly with thrombocytopenia, ascites and portosystemic collaterals, the patients were divided into noCSPH (n = 113), compensated CSPH (cCSPH, ≥1 finding without ascites; n = 55) and decompensated CSPH (dCSPH, ascites ± other findings; n = 27). T1 times were measured in the liver, spleen and abdominal aorta in the unenhanced and contrast-enhanced T1 maps. Native T1 times and ΔT1 of the liver and spleen as well as ECV of the spleen were compared between groups using the Kruskal-Wallis test with Dunn's post hoc test. Furthermore, cutoff values for group differentiation were calculated using ROC analysis with Youden's index. RESULTS: ΔT1 of the liver was significantly lower in patients with cCSPH and dCSPH (p < 0.001) compared to patients with noCSPH. In the ROC analyses for differentiation between noCSPH and CSPH (cCSPH + dCSPH), a cutoff of < 0.67 for ΔT1 of the liver (AUC = 0.79) performed better than ΔT1 (AUC = 0.69) and ECV (AUC = 0.63) of the spleen with cutoffs of > 0.29 and > 41.9, respectively. CONCLUSION: ΔT1 of the liver and spleen in addition to ECV of the spleen allow for determination of CSPH on routine Gd-EOB-DTPA liver MRI.

Integrative echocardiographic assessment of patients with secondary mitral regurgitation undergoing transcatheter edge-to-edge repair.

OBJECTIVES: To investigate whether the integrative echocardiographic criteria used in the cardiovascular outcomes assessment of the mitraclip percutaneous therapy (COAPT) for heart failure patients with functional mitral regurgitation study predict outcomes after edge-to-edge trancatheter mitral valve repair (TMVr) for the treatment of secondary mitral regurgitation (SMR). BACKGROUND: Two randomized controlled trials comparing TMVr to medical treatment reported conflicting findings. Differences in patient selection criteria may have contributed to these diverging results. METHODS: Patients undergoing TMVr were stratified following the integrative COAPT echocardiographic criteria in noneligible and eligible patients who were further classified into three tiers according to effective regurgitant orifice (EROA) (Tier 1: EROA ≥ 0.3cm2 ; Tier 2: EROA 0.2cm2 and 0.29cm2 ; Tier 3: EROA<0.2cm2 ) combined with several other severity criteria. We assessed between group differences in all-cause mortality, successful SMR reduction, and symptom relief from baseline to 2-year follow-up. RESULTS: Between March 2011 and March 2018, 138 patients (mean age 75 years) satisfying the inclusion criteria underwent TMVr for treatment of symptomatic SMR. The mean EROA area was 0.35 ± 0.17 mm2 . Ten patients (7%) died within 30 days, 29 (21%) within 12 months, and 41 (30%) within 2 years. After stratification according to the COAPT echocardiographic criteria that were fulfilled in 72% of the studied population, Tier 2 patients (45%), as well as noneligible patients (38%) had a higher mortality rate compared to those in Tier 1 (19%). CONCLUSIONS: SMR patients stratified into tiers according to the COAPT integrative echocardiographic criteria have diverging prognostic and symptomatic benefit after edge-to-edge TMVr.

Multimodality Imaging Assessment of Myocardial Fibrosis.

Myocardial fibrosis, seen in ischemic and nonischemic cardiomyopathies, is associated with adverse cardiac outcomes. Noninvasive imaging plays a key role in early identification and quantification of myocardial fibrosis with the use of an expanding array of techniques including cardiac magnetic resonance, computed tomography, and nuclear imaging. This review discusses currently available noninvasive imaging techniques, provides insights into their strengths and limitations, and examines novel developments that will affect the future of noninvasive imaging of myocardial fibrosis.

Role of quantitative myocardial blood flow and 13N-ammonia washout for viability assessment in ischemic cardiomyopathy.

OBJECTIVE: Positron emission tomography (PET) integrating assessment of perfusion with 13N-ammonia (NH3) and viability with 18F-fluorodeoxyglucose (FDG) has high accuracy to identify viable, hibernating myocardium. We tested whether quantification of myocardial blood flow (MBF) and washout (k2) can predict myocardial viability using FDG as standard of reference. METHODS: In 180 consecutive patients with ischemic cardiomyopathy, myocardium was categorized on a segment-level into normal, ischemic, hibernating, and scar. From dynamic images, stress MBF, rest MBF, and k2 were derived and myocardial flow reserve (MFR) and volume of distribution (VD) were calculated. RESULTS: Across myocardial tissues, all parameters differed significantly. The area under the curve (AUC) was 0.564 (95% CI 0.527-0.601), 0.635 (0.599-0.671), 0.553 (0.516-0.591), 0.520 (0.482-0.559), and 0.560 (0.522-0.597) for stress MBF, rest MBF, MFR, k2, and VD. The generalized linear mixed model correctly classified 81% of scar as viable, hibernating myocardium. If the threshold of rest MBF to predict viability was set to 0.45 mL·min-1·g-1, sensitivity and specificity were 96% and 12%, respectively. CONCLUSION: Quantitative NH3 PET parameters have low to moderate diagnostic performance to predict viability in ischemic cardiomyopathy. However, if rest MBF falls below 0.45 mL·min-1·g-1, viability testing by FDG-PET may be safely deferred.

Noninvasive Assessment of Coronary Artery Disease - Anatomical versus Functional Imaging and the Marginal Role of Exercise Electrocardiograms.

Coronary artery disease (CAD) is the leading cause of morbidity and mortality in the industrialized countries. Assessment of symptomatic patients with suspected obstructive CAD is a common reason for a clinical visit. Noninvasive anatomical and functional imaging are established tools to rule-in and rule-out CAD, to assess the severity of disease and to determine the potential risk of future cardiovascular events. In this review, we discuss the updated Guidelines from the European Society of Cardiology on Chronic Coronary Syndromes and explore the different imaging modalities used in current clinical practice for the noninvasive assessment of CAD. The pros and cons of each method, especially comparing anatomical and functional testing, are presented. Furthermore we we address the practical clinical aspects in the selection of the optimal noninvasive tests according to clinical need.

Incremental value of extracellular volume assessment by cardiovascular magnetic resonance imaging in risk stratifying patients with suspected myocarditis.

Cardiovascular magnetic resonance imaging (CMR) has become a key investigative tool in patients with suspected myocarditis. However, the prognostic implications of T1 mapping, including extracellular volume (ECV) calculation, is less clear. Patients with suspected myocarditis who underwent CMR evaluation, including T1 mapping at our institution were included. CMR findings including late gadolinium enhancement (LGE), left ventricular ejection fraction (LVEF), native T1 mapping, and ECV calculation were associated with first major adverse cardiac events (MACE). MACE included a composite of all-cause death, heart failure hospitalization, heart transplantation, documented sustained ventricular arrhythmia, and recurrent myocarditis. One hundred seventy-nine patients with a mean age of 49 ± 15 years were identified. Seventy nine individuals (44%) were female. Mean LVEF was 48 ± 16. At a median follow-up of 4.1 [interquartile-range (IQR) 2.2-6.1] years, 22 (12%) patients experienced a MACE. Mean ECV (per 10%) was significantly associated with MACE (HR 2.09, 95% CI 1.07-4.08, p = 0.031). Presence of ECV ≥ 35% demonstrated significant univariable association with MACE (HR 3.3, 95% CI 1.43-7.97, p = 0.005) and such association was maintained when adjusted to LVEF (HR 3.42, 95% CI 1.42-7.94, p = 0.006). ECV ≥ 35% portended a greater than threefold increased hazards to MACE adjusted to LGE presence (HR 3.14, 95% CI 1.29-7.36, p = 0.012). In patients without LGE, ECV ≥ 35% portended a greater than sixfold increased hazards (HR 6.6, p = 0.010). In the multivariable model including age, LVEF and LGE size, only ECV ≥ 35% maintained its significant association with outcome. ECV calculation by CMR is a useful tool in the risk stratification of patients with clinically suspected myocarditis, incremental to LGE and LVEF.