Adenosine Stress Research Articles

Prognostic value of quantitative anatomical and functional measures of coronary artery disease in diabetic and non-diabetic patients

Abstract Background Diabetes is associated with increased risk of coronary artery disease (CAD). However, the relative prognostic importance of anatomical and functional findings of CAD in the presence vs. absence of diabetes is incompletely understood. Technological advances have made quantitative analysis of coronary artery plaques and stenosis feasible by coronary computed tomography angiography (CTA). In turn, positron emission tomography (PET) enables absolute quantification of myocardial blood flow (MBF). Purpose To study long-term prognostic value of quantified severity of coronary atherosclerosis and myocardial perfusion in non-diabetic vs. diabetic patients with suspected CAD. Methods From two academic medical centres, we identified symptomatic patients with suspected CAD who had undergone coronary CTA and [15O]H2O PET myocardial perfusion imaging during adenosine stress. Based on artificial intelligence -guided quantitative analysis of coronary CTA scans, the anatomical severity of CAD was measured as the presence of obstructive CAD (≥50% diameter stenosis) and percent atheroma volume (PAV; higher vs. lower than median). The functional severity of CAD was measured as the presence of regional myocardial ischemia (≥2 adjacent segments with stress MBF <2.3 ml/g/min) and global stress MBF (<2.2 ml/g/min vs. ≥ 2.2 ml/g/min) by PET. Annual rates of adverse events (AER) including all-cause mortality, myocardial infarction (MI), and unstable angina pectoris (UAP) were evaluated. Results Among 1311 patients, 251 (19%) had diabetes. Patients with diabetes had more frequently obstructive CAD (55% vs. 43%, p<0.001) and regional myocardial ischemia (51% vs. 43%, p=0.015), higher plaque burden by PAV (12% vs. 7%, p<0.001), and lower global stress MBF (2.78 ml/g/min vs. 3.05 ml/g/min, p<0.001). During median follow-up of 7.1 years, 171 (13.0%) patients experienced AE (85 deaths, 56 MIs, and 30 UAPs). Patients with diabetes had higher AER than non-diabetic patients (3.1% vs. 1.6%, p<0.001). The presence of obstructive stenosis was associated with increased AER in non-diabetic (2.6% vs. 1.0%, p<0.001) and diabetic patients (4.2% vs. 1.9%, p<0.001). High plaque burden by PAV was associated with increased AER in non-diabetic (2.8% vs. 0.7%, p<0.001) and diabetic patients (3.9% vs. 1.7%, p<0.001). The presence of regional myocardial ischemia was associated with increased AER in non-diabetic (2.5% vs. 1.1%, p<0.001), but not in diabetic patients (3.4% vs. 2.7%, p=0.238). Low global stress MBF was associated with increased AER in non-diabetic (2.9% vs. 1.3%, p<0.001), but not among diabetic patients (3.2% vs. 3.0%, p=0.286). Conclusions Diabetes was associated with more advanced CAD. Quantified severity of anatomical findings predicted long-term adverse outcome in non-diabetic and diabetic patients. In contrast, functional imaging risk stratified non-diabetic patients, whereas diabetic patients had impaired long-term outcome irrespective of perfusion findings.

Regional distribution of diffuse fibrosis in the basal and mid-ventricular AHA segments in patients with type 2 diabetes

Abstract Introduction Cardiovascular magnetic resonance (CMR) research including from our research group, has documented that patients (pts.) with type 2 diabetes (DM2) even without symptoms exhibit subtle to moderately increased myocardial extracellular volume (ECV). ECV is an imaging biomarker of diffuse fibrosis. Also, our prior research has revealed a prevalence of approx. 10% for non-ischemic late gadolinium enhancement (LGE). Intriguingly, these LGE lesions manifested in a distinct pattern, situated in the basal lateral or infero-lateral positions. We postulate that these lesions may represent the end-stage of severe diffuse fibrosis, potentially influenced by factors such as increased shear wall stress. Purpose To investigate if pts. with DM2 with known high global ECV had higher regional ECV in the basal and lateral or infero-lateral AHA segments compared to other segments. Method A case-control study of 20 healthy controls, 20 pts. with DM2 with low ECV (ECV<28%), 20 pts. with DM2 with high ECV (ECV>29%), and 20 pts. with DM2 with non-ischemic LGE (LGE+). Pts. were identified from a cross-sectional cohort of pts. with DM2. All subjects underwent physical examination and extensive CMR with T1 mapping before and after gadolinium contrast, and myocardial perfusion at rest and during adenosine stress. The regional ECV values for the basal and the mid-ventricular short axis slide were analysed using the AHA segments model: segments 1 to 12. Results All groups (grp.) had comparable age and sex distribution. In the DM2 grp. there was a difference between the no. of pts. with DM2 duration >10 years (low ECV 11(55%), high ECV 12(60%), LGE+ 16(80%), however statistically significant. Global ECV were: Controls (mean±sd) 26.7±1.6%, Low ECV 26.3±1.4%, High ECV 32.0±2.9%, LGE+ 29.5±2.6%, p<0.001. Control subjects had regional ECV between 24.4±2% to 27.3±2% (p<0.001), highest values in the septum. The DM2 grp. with low ECV had regional ECV values of 24.5±3% to 29.2±4%, highest values in the basal inferior and septal parts (segments 2-4). The high ECV grp. had regional ECV values between 28.3±4% and 35.3±6 % with very high values in the basal and the mid-ventricular septum, inferior, and inferolateral part (segments 2-5 and 8-11). The DM2 group LGE+ had values between 26.6±3% and 34.5±7%, highest values in the basal slice in the septum, inferior, and infero-lateral parts (segments 2-5). We found no significant difference in the regional myocardial perfusion reserve index. Conclusion This evidence indicates that diffuse fibrosis in DM2 cardiomyopathy tends to concentrate in the septum and inferolateral regions. However, among pts. with non-ischemic LGE lesions, we observed normal ECV in the anterior segments, in contrast to the high ECV group where all segments exceeded normal levels, albeit with notable regional variations. Subsequent investigations should prioritize uncovering the underlying reasons for this specific regional distribution of diffuse fibrosis.AHA segments 1-12 mapsAHA segments 1-12 maps

Assessment of cardiopulmonary exercise capacity in suspected heart failure with preserved ejection fraction: impact of coronary flow velocity reserve and body fat

Abstract Background and objectives Heart failure with preserved ejection fraction (HFpEF) has various pathophysiology including coronary microvascular dysfunction (CMD), obesity, and frailty. In the present study, we aimed to assess the cardiopulmonary exercise capacity according to coronary microvascular function and body composition in patients with suspected HFpEF. Methods Patients with chest symptoms with non-obstructive coronary artery disease (<50% stenosis) and preserved left ventricle (LV) ejection fraction (≥50%) were enrolled. LV end-diastolic pressure was measured during coronary angiography. All patients underwent body composition analysis, adenosine stress echocardiography with the evaluation of coronary blood flow, and cardiopulmonary exercise test assessing maximal oxygen consumption (VO2max). Coronary flow velocity reserve (CFvR) was defined as the ratio of peak to baseline mean diastolic velocity of coronary blood flow. Association between VO2max and CFvR as well as body composition was assessed. Results Of the 106 patients (mean age 63.5), 54 (50.9%) were women, 52.4% had hypertension, and 28.6% had diabetes. Baseline LV end-diastolic pressure was 15.3 ± 5.5 mmHg. Median Heart Failure Association-PEFF score was 3, while medial e’ velocity was 6.7 ± 2.0 cm/s and E/e’ was 9.6 (7.6 – 12.0). Mean diastolic velocity of coronary blood flow was 0.17 [interquartile range (IQR) 0.13 – 0.23] m/sec at baseline, while it increased to 0.46 [IQR 0.38 – 0.57] m/sec at peak, resulting in CFvR of 2.75 [IQR 2.10 – 3.67]. Eighteen (17.1%) patients had CMD (CFvR <2.0). VO2max was 23.1 ± 5.4 mL/kg/min with lower value in women (21.7 ± 4.8 vs. 24.5 ± 5.6 mL/kg/min, p = 0.007). CFvR was directly related to VO2max (r = 0.350, p <0.001). In body composition, skeletal muscle mass index, percent body fat, and visceral fat area were associated with VO2max. In multivariable analysis, age, visceral fat area or percent body fat, and CFvR were linearly correlated with VO2max, and estimated VO2max was well correlated with measured VO2max. Conclusions Cardiopulmonary exercise capacity represented by VO2max was correlated with CFvR and body composition including skeletal muscle mass index, percent body fat, and visceral fat area in patients with suspected HFpEF. VO2max could be estimated by CFvR and fat component in the body.

Serial quantitative stress perfusion cardiac magnetic resonance in patients undergoing coronary artery bypass grafting; prediction of symptomatic benefit

Abstract Background Serial multiparametric cardiovascular magnetic resonance (CMR) in patients undergoing coronary artery bypass grafting (CABG) may provide mechanistic insight into dynamic and persistent abnormalities of the myocardium in patients with stable coronary artery disease (CAD). Objectives To assess for dynamic CMR markers of myocardial hypoperfusion and cardiac remodelling in patients undergoing CABG. Methods Patients with CAD awaiting elective CABG were recruited into an observational cohort study. Baseline evaluation included bloods, Seattle Angina Questionnaire-7, and adenosine stress perfusion CMR. Automated fully quantitative stress and rest myocardial blood flow was calculated, alongside assessment of the visual ischaemic burden. Native and post-contrast septal T1 indices were also measured. Repeat evaluation at 6-12 months post CABG was performed. Results Of 43 patients who underwent serial evaluation with CMR (mean age 62.1±9.3, median LVEF 68% [IQR: 62-73%]), there was improvement in the median visual ischaemic burden (18% [IQR: 11-21] vs 42% [IQR: 27-51], P<0.001), mean global stress myocardial blood flow (1.5±0.5 ml/min/g vs 1.3±0.5 ml/min/g, P=0.002) and median global myocardial perfusion reserve (2.4 [IQR: 1.7-2.8] vs 1.7 [IQR: 1.4-2.2], P=0.002) following CABG. Greater improvement in the SAQ-7 summary score was associated with a larger visual ischaemic burden at baseline (ρ=0.44, P=0.004) and a greater decrease in the visual ischaemic burden following CABG (ρ=-0.38, P=0.02). Quantitative MBF metrics did not associate with baseline or change in SAQ-7 summary score. Mean LV extracellular matrix volume decreased following CABG (16.6±3.6ml/m2 vs 18.2±4.6ml/m2, P=0.009). Conclusion Multiparametric CMR identifies dynamic changes in markers of myocardial perfusion and interstitial fibrosis in patients following CABG. Visual assessment of inducible myocardial hypoperfusion may identify patients who will derive the most symptomatic benefit from CABG. The results, however, suggest an important degree of residual inducible ischaemia and an unclear clinical role for CMR-derived MBF calculations.Serial CMR perfusion dataAssociation of SAQ with perfusion

Quantitative perfusion by cardiac magnetic resonance analysis reveals compromised myocardial perfusion in patients with angina with non-obstructive coronary artery disease

Abstract Introduction Stress perfusion cardiac magnetic resonance (CMR) visually detects myocardial ischemia through first-pass contrast-enhanced imaging by identifying perfusion defects. However, in generalized myocardial diseases like angina with non-obstructed coronary arteries (ANOCA), visual assessment becomes challenging due to diffuse sub-endocardial perfusion defects, or the findings may even falsely appear normal. Fully automated quantitative perfusion (QP), allowing absolute quantification of myocardial blood flow (MBF) and deriving myocardial perfusion reserve (MPR), might increase diagnostic accuracy in ANOCA patients. Therefore, the purpose of this study is to test the use of QP in detecting ANOCA diagnosed by the invasive golden standard. Methods This study is a cross-sectional cohort study assessing the use of fully automated QP CMR in patients with ANOCA compared with age- and sex-matched healthy controls. All participants underwent adenosine stress perfusion CMR, including visual assessment and quantification of MBF and MPR. Furthermore, all ANOCA patients underwent intracoronary function testing (ICFT) to idenity vasospasm and/or coronary microvascular dysfunction. Results This study included 24 ANOCA patients (83% women, 56.8±8.9 years) and 25 healthy controls (80% women, 56.2±7.2 years). Visual perfusion assessment showed no group differences in terms of perfusion defects (p=0.536). However, in QP, ANOCA patients had higher relative MBF than healthy controls (0.83±0.15 vs 0.74±0.17, p=0.046), while global perfusion was significantly lower during stress (2.43±0.72 vs 2.99±0.65 ml/g/min, p=0.006). Moreover, ANOCA patients had significantly lower MPR than healthy controls (2.24 ±0.79 vs 2.68 ±0.64, respectively p=0.036), with a higher prevalence of an impared MPR (50% vs. 20%, p=0.027). MPR was not significantly different between the various ANOCA entities as stratified during ICFT (p=0.766). Conclusions ANOCA patients displayed significantly reduced MPR, indicating impaired perfusion. The prevalence of diminished MPR was higher in the ANOCA group compared to the healthy controls, constrasting with no differences in visual assessment. These results are promising and underscores the possibilities of the use of QP in detecting vasomotor dysfunction non-invasively in ANOCA patients.Quantitative Perfusion by CMR results

Effect of aortic valve replacement on myocardial perfusion and exercise capacity in patients with severe aortic stenosis

Aortic valve replacement (AVR) leads to reverse cardiac remodeling in patients with aortic stenosis (AS). The aim of this secondary pooled analysis was to assess the degree and determinants of changes in myocardial perfusion post AVR, and its link with exercise capacity, in patients with severe AS. A total of 68 patients underwent same-day echocardiography and cardiac magnetic resonance imaging with adenosine stress pre and 6–12 months post-AVR. Of these, 50 had matched perfusion data available (age 67 ± 8 years, 86% male, aortic valve peak velocity 4.38 ± 0.63 m/s, aortic valve area index 0.45 ± 0.13cm2/m2). A subgroup of 34 patients underwent a symptom-limited cardiopulmonary exercise test (CPET) to assess maximal exercise capacity (peak VO2). Baseline and post-AVR parameters were compared and linear regression was used to determine associations between baseline variables and change in myocardial perfusion and exercise capacity. Following AVR, stress myocardial blood flow (MBF) increased from 1.56 ± 0.52 mL/min/g to 1.80 ± 0.62 mL/min/g (p < 0.001), with a corresponding 15% increase in myocardial perfusion reserve (MPR) (2.04 ± 0.57 to 2.34 ± 0.68; p = 0.004). Increasing severity of AS, presence of late gadolinium enhancement, lower baseline stress MBF and MPR were associated with a greater improvement in MPR post-AVR. On multivariable analysis low baseline MPR was independently associated with increased MPR post-AVR. There was no significant change in peak VO2 post-AVR, but a significant increase in exercise duration. Change in MPR was associated with change in peak VO2 post AVR (r = 0.346, p = 0.045). Those with the most impaired stress MBF and MPR at baseline demonstrate the greatest improvements in these parameters following AVR and the magnitude of change in MPR correlated with improvement in peak VO2, the gold standard measure of aerobic exercise capacity.

Safety and feasibility of adenosine stress cardiac MRI in heart transplant recipients.

Safety and feasibility of adenosine stress cardiac MRI in heart transplant recipients.

Assessment of myocardial microvascular dysfunction in patients with different stages of diabetes mellitus: An adenosine stress perfusion cardiac magnetic resonance study

PurposeTo examine myocardial perfusion and T1 mapping indicesin individuals with type 2 diabetes mellitus (T2DM) at various stages of glycemic control and whether uncontrolled glycemic levels would worsen myocardial microvascular function. MethodCardiac magnetic resonance examinations were performed on 114 T2DM patients without obstructive coronary artery disease and 55 matched controls. Participants were further divided into four subgroups: Q1 (control); Q2 (prediabetes); Q3 (controlled T2DM) and Q4 (uncontrolled T2DM). The correlation between glycosylated hemoglobin (HbA1c) levels and myocardial perfusion parameters was evaluated. ResultsGlobal myocardial perfusion reserve index (MPRI) was significantly reduced in the Q3 and Q4 subgroups compared to the Q1 or Q2 subgroup (all P<0.001). Compared with the Q1 subgroup, global stress T1 reactivity (stress ΔT1) was significantly reduced in the Q3 and Q4 subgroups (P=0.004 and < 0.001, respectively), but elevated in the Q2 subgroup (P=0.018). Global extracellular volume (ECV) was considerably higher in the Q2 subgroup and gradually rose in the Q3 and Q4 subgroups compared to the Q1 subgroup (P=0.011, 0.001, and 0.007, respectively). HbA1c levels correlated negatively with global MPRI and stress ΔT1, but positively with global ECV (β = -1.993, P<0.001; β = -0.180, P<0.001; and β = 0.127, P<0.001, respectively). ConclusionsGlobal stress ΔT1 reduced in T2DM patients but rose in prediabetes patients. Compared to MPRI, the ECV parameter can indicate diabetes-induced coronary microvascular dysfunction earlier and persists throughout the disorder. Myocardial perfusion and T1 mapping at stress can be used to detect early signs of microvascular dysfunction and subclinical risk factors in patients with T2DM.

Rest and stress aortic flow analysis by CMR in MyoFit46

Abstract Background Aortic stiffness is a strong predictor of future cardiovascular events and all-cause mortality. Aortic stiffness has never been measured during adenosine stress perfusion before, and may provide valuable relationship about this relationship. Aim To investigate if there are differences between aortic stiffness and conditions of rest and stress perfusion, in an older age-homogenous population-based cohort. Methods 203 participants from the longitudinal 1946 Medical Research Council National Survey of Health and Development British birth cohort were included. Cardiovascular Magnetic Resonance (CMR) imaging was performed at rest and during adenosine stress perfusion. 3 established and validated biomarkers of aortic stiffness were reported - pulse wave velocity, distensibility and beta stiffness, at rest and stress perfusion. All variables were non-normally distributed, therefore the Wilcoxon signed-rank test was used to look for significant differences between rest and stress. Results Aortic stiffness increased significantly during adenosine stress perfusion, shown by all biomarkers of aortic stiffness used: pulse wave velocity (p = &amp;lt;0.001), distensibility (p = &amp;lt;0.001), and beta stiffness (p = &amp;lt;0.001). However, the aortas of participants with a higher resting aortic stiffness at baseline were less dynamic (little if any aortic stiffness change with stress) when compared to those with low resting aortic stiffness. Conclusion It is feasible to measure aortic stiffness during adenosine stress perfusion. In healthy aortas, aortic stiffness increases in the acute phase of adenosine stress suggesting a new potential mechanism for the body response to adenosine – peripheral chemoreceptor reflex activation. Stiffer arteries at baseline are less modifiable and stress aortic flow CMR has the potential to identify these persons permitting early targeted therapy. Change in aortic stiffness, measured by stress aortic flow CMR is therefore a potential non-invasive biomarker of aortic health.

Splenic switch-off in [15O]H2O-positron emission tomography myocardial perfusion imaging using parametric blood flow images

BackgroundEvaluation of sufficient adenosine response constitutes a significant challenge in myocardial perfusion imaging (MPI). Splenic switch-off in MPI studies denotes a visually (qualitatively) reduced splenic radiotracer signal during adenosine stress and is considered indicative of sufficient cardiac vasodilation. In this study, we examined semi-quantitative and quantitative approaches to splenic switch-off assessment using [15O]H2O-PET with either summed activity images or calculated parametric splenic blood flow images. MethodsCohort 1: 90 clinical patients undergoing [15O]H2O MPI in whom adenosine response was considered clinically adequate were identified to characterize the corresponding splenic switch-off. Spleen stress/rest-ratio (SSR-ratio) was calculated as spleen stress signal intensity/spleen rest signal intensity on both summed activity and parametric blood flow images.Cohort 2: Twenty-five patients with repeat MPI due to suspected insufficient adenosine response were identified to observe if splenic switch-off on the initial MPI could predict the outcome of the repeat MPI.Cohort 3: Fifty-four patients who were considered adenosine responders on MPI and who had a coronary angiogram (CAG) follow-up within 3 months after MPI served as a separate validation group. ResultsSplenic switch-off was present in most patients with a clinically sufficient adenosine response (Cohort 1), illustrated by both visual (74.4%–86.7%), semi-quantitative (summed activity images) (85.6%), and quantitative (parametric blood flow images) (92.2%) evaluation, which corresponds to the distribution in patients with sufficient adenosine response and follow-up CAG (Cohort 3). In patients suspected of insufficient adenosine response on the initial MPI (Cohort 2), the repeat MPI only yielded different myocardial blood flow (MBF) results if the initial SSR-ratio was >0.90 on splenic parametric blood flow images. Conclusionquantitative splenic switch-off assessment on parametric blood flow images was superior to the semi-quantitative splenic switch-off approach. Patients with a suspected insufficient initial adenosine response and SSR-ratio >0.90 can benefit from a repeat MPI. Thus, the integration of quantitative splenic switch-off using parametric blood flow images in the evaluation of adenosine response may support future clinical decision-making.

Clinical implementation of a fully automated quantitative perfusion cardiovascular magnetic resonance imaging workflow with a simplified dual-bolus contrast administration scheme

This study clinically implemented a ready-to-use quantitative perfusion (QP) cardiovascular magnetic resonance (QP CMR) workflow, encompassing a simplified dual-bolus gadolinium-based contrast agent (GBCA) administration scheme and fully automated QP image post-processing. Twenty-five patients with suspected obstructive coronary artery disease (CAD) underwent both adenosine stress perfusion CMR and an invasive coronary angiography or coronary computed tomography angiography. The dual-bolus protocol consisted of a pre-bolus (0.0075 mmol/kg GBCA at 0.5 mmol/ml concentration + 20 ml saline) and a main bolus (0.075 mmol/kg GBCA at 0.5 mmol/ml concentration + 20 ml saline) at an infusion rate of 3 ml/s. The arterial input function curves showed excellent quality. Stress MBF ≤ 1.84 ml/g/min accurately detected obstructive CAD (area under the curve 0.79; 95% Confidence Interval: 0.66 to 0.89). Combined visual assessment of color pixel QP maps and conventional perfusion images yielded a diagnostic accuracy of 84%, sensitivity of 70% and specificity of 93%. The proposed easy-to-use dual-bolus QP CMR workflow provides good image quality and holds promise for high accuracy in diagnosis of obstructive CAD. Implementation of this approach has the potential to serve as an alternative to current methods thus increasing the accessibility to offer high-quality QP CMR imaging by a wide range of CMR laboratories.

Prognostic value of a novel artificial intelligence-based coronary CTA-derived ischemia algorithm among patients with normal or abnormal myocardial perfusion

BackgroundAmong patients with obstructive coronary artery disease (CAD) on coronary computed tomography angiography (CTA), downstream positron emission tomography (PET) perfusion imaging can be performed to assess the presence of myocardial ischemia. A novel artificial-intelligence-guided quantitative computed tomography ischemia algorithm (AI-QCTischemia) aims to predict ischemia directly from coronary CTA images. We aimed to study the prognostic value of AI-QCTischemia among patients with obstructive CAD on coronary CTA and normal or abnormal downstream PET perfusion. MethodsAI-QCTischemia was calculated by blinded analysts among patients from the retrospective coronary CTA cohort at Turku University Hospital, Finland, with obstructive CAD on initial visual reading (diameter stenosis ≥50%) being referred for downstream 15O-H2O-PET adenosine stress perfusion imaging. All coronary arteries with their side branches were assessed by AI-QCTischemia. Absolute stress myocardial blood flow ≤2.3 ​ml/g/min in ≥2 adjacent segments was considered abnormal. The primary endpoint was death, myocardial infarction, or unstable angina pectoris. The median follow-up was 6.2 [IQR 4.4–8.3] years. Results662 of 768 (86%) patients had conclusive AI-QCTischemia result. In patients with normal 15O-H2O-PET perfusion, an abnormal AI-QCTischemia result (n ​= ​147/331) vs. normal AI-QCTischemia result (n ​= ​184/331) was associated with a significantly higher crude and adjusted rates of the primary endpoint (adjusted HR 2.47, 95% CI 1.17–5.21, p ​= ​0.018). This did not pertain to patients with abnormal 15O-H2O-PET perfusion (abnormal AI-QCTischemia result (n ​= ​269/331) vs. normal AI-QCTischemia result (n ​= ​62/331); adjusted HR 1.09, 95% CI 0.58–2.02, p ​= ​0.794) (p-interaction ​= ​0.039). ConclusionAmong patients with obstructive CAD on coronary CTA referred for downstream 15O-H2O-PET perfusion imaging, AI-QCTischemia showed incremental prognostic value among patients with preserved perfusion by 15O-H2O-PET imaging, but not among those with reduced perfusion.

Coronary Microvascular Dysfunction in Acute Cholestasis-Induced Liver Injury.

Previous studies have shown cardiac abnormalities in acute liver injury, suggesting a potential role in the associated high mortality. We designed an experimental study exploring the short-term effects of acute cholestasis-induced liver injury on cardiac function and structure in a rodent bile duct ligation (BDL) model to elucidate the potential interplay. Thirty-seven male Sprague-Dawley rats were subjected to BDL surgery (n = 28) or served as sham-operated (n = 9) controls. Transthoracic echocardiography, Doppler evaluation of the left anterior descending coronary artery, and myocardial contrast echocardiography were performed at rest and during adenosine and dobutamine stress 5 days after BDL. Immunohistochemical staining of myocardial tissue samples for hypoxia and inflammation as well as serum analysis were performed. BDL animals exhibited acute liver injury with elevated transaminases, bilirubin, and total circulating bile acids (TBA) 5 days after BDL (TBA control: 0.81 ± 2.54 µmol/L vs. BDL: 127.52 ± 57.03 µmol/L; p < 0.001). Concurrently, cardiac function was significantly impaired, characterized by reduced cardiac output (CO) and global longitudinal strain (GLS) in the echocardiography at rest and under pharmacological stress (CO rest control: 120.6 ± 24.3 mL/min vs. BDL 102.5 ± 16.6 mL/min, p = 0.041; GLS rest control: -24.05 ± 3.8% vs. BDL: -18.5 ± 5.1%, p = 0.01). Myocardial perfusion analysis revealed a reduced myocardial blood flow at rest and a decreased coronary flow velocity reserve (CFVR) under dobutamine stress in the BDL animals (CFVR control: 2.1 ± 0.6 vs. BDL: 1.7 ± 0.5 p = 0.047). Immunofluorescence staining indicated myocardial hypoxia and increased neutrophil infiltration. In summary, acute cholestasis-induced liver injury can lead to impaired cardiac function mediated by coronary microvascular dysfunction, suggesting that major adverse cardiac events may contribute to the mortality of acute liver failure. This may be due to endothelial dysfunction and direct bile acid signaling.

Normal values of myocardial blood flow measured with dynamic myocardial CT perfusion.

Dynamic myocardial CT perfusion (DM-CTP) can, in combination with coronary CT angiography (CCTA), provide anatomical and functional evaluation of coronary artery disease (CAD). However, normal values of myocardial blood flow (MBF) are needed to identify impaired myocardial blood supply in patients with suspected CAD.We aimed to establish normal values for MBF measured using DM-CTP, to assess the effects of age and sex, and to assess regional distribution of MBF. A total of 82 healthy individuals (46 women) aged 45-78 years with normal coronary arteries by CCTA underwent either rest and adenosine stress DM-CTP (n = 30) or adenosine induced stress DM-CTP only (n = 52). Global and segmental MBF were assessed. Global MBF at rest and during stress were 0.93 ± 0.42 mL/min/g and 3.58 ± 1.14 mL/min/g respectively. MBF was not different between the sexes (P = 0.88 at rest and P = 0.61 during stress) and no correlation was observed between MBF and age (P = 0.08 at rest and P = 0.82 during stress). Among the 16 myocardial segments, significant inter-segmental differences were found (P < 0.01), which was not related to age, sex or coronary dominance. Myocardial blood flow assessed by DM-CTP in healthy individuals with normal coronary arteries displays significant intersegmental heterogeneity which does not seem to be affected by age, sex or coronary dominance. Normal values of myocardial blood flow may be helpful in the clinical evaluation of suspected myocardial ischemia using DM-CTP.

Kiosk 1R-TB-08 - Invasive Coronary Angiography Has Limited Diagnostic Accuracy for Detecting Significant Reduction of Myocardial Perfusion During Adenosine Stress

Kiosk 1R-TB-08 - Invasive Coronary Angiography Has Limited Diagnostic Accuracy for Detecting Significant Reduction of Myocardial Perfusion During Adenosine Stress

Kiosk 9R-FB-07 - Safety and Feasibility of Adenosine Stress CMR in Heart Transplant Recipients with Suspected Cardiac Allograft Vasculopathy

Kiosk 9R-FB-07 - Safety and Feasibility of Adenosine Stress CMR in Heart Transplant Recipients with Suspected Cardiac Allograft Vasculopathy

Reduced response to regadenoson with increased weight: An artificial intelligence–based quantitative myocardial perfusion study

BackgroundThere is conflicting evidence regarding the response to a fixed dose of regadenoson in patients with high body weight. The aim of this study was to evaluate the effectiveness of regadenoson in patients with varying body weights using novel quantitative cardiovascular magnetic resonance (CMR) perfusion parameters in addition to standard clinical markers. MethodsConsecutive patients with typical angina and/or risk factors for coronary artery disease (N = 217) underwent regadenoson stress CMR perfusion imaging using a dual-sequence quantitative protocol with perfusion parameters generated from an artificial intelligence (AI)–based algorithm. CMR was performed on 1.5T scanners using a standard 0.4 mg injection of regadenoson. A cohort of consecutive patients undergoing adenosine stress perfusion (N = 218) was used as a control group. ResultsAn inverse association of myocardial perfusion reserve and weight (mean decrease −0.05 per 10 kg increase, 95% confidence interval [CI] −0.009/−0.0001, P = 0.045) was noted in the regadenoson group but not in patients stressed with adenosine (P = 0.77). Adjusted logistic regression analysis revealed a 10 kg increase resulted in 36% increased odds for inadequate stress response (odds ratio [OR] = 1.36, 95% CI 1.10–1.69, P = 0.005). Moreover, a significant interaction (OR = 1.09, 95% CI 1.02–1.16, P = 0.012) between stressor type (regadenoson vs adenosine) and weight was noted. This was also confirmed in the propensity-matched subgroup (P = 0.024) and was not attenuated after adjustment (P = 0.041). Body surface area (BSA) (P = 0.006) but not body mass index (P = 0.055) was differentially associated with inadequate response conditional to the stressor used, and this association remained significant after adjustment for confounders (P = 0.025). Patients in the highest quartile of weight (>93 kg) or BSA (>2.06 m2) had substantially increased odds for inadequate response with regadenoson (OR = 8.19, 95% CI 2.04–32.97, P = 0.003 for increased weight and OR = 7.75, 95% CI 1.93–31.13, P = 0.004 for increased BSA). Both weight and BSA had excellent discriminative ability for inadequate regadenoson response (receiver operating characteristic area under curves 0.84 and 0.83, respectively). ConclusionUsing quantitative perfusion CMR in patients undergoing pharmacological stress with regadenoson, we found an inverse relationship between patient weight and both clinical response and myocardial perfusion parameters. A fixed-dose bolus approach may not be adequate to induce maximal hyperemia in patients with increased weight. Weight-adjusted stressors, such as adenosine, may be considered instead in patients with body weight >93 kg and BSA >2.06 m2.

Prognostic value of stress perfusion cardiac magnetic resonance in patients with prediabetes and suspected coronary artery disease.

Stress perfusion cardiac magnetic resonance (CMR) is an accurate and comprehensive modality for evaluating patients with suspected coronary artery disease (CAD), but its prognostic value in prediabetic patients is uncertain. This retrospective study included 452 consecutive prediabetic patients without prior diagnoses of CAD who underwent adenosine stress perfusion CMR. The primary endpoint was major adverse cardiovascular events (MACE), defined as cardiovascular death, nonfatal myocardial infarction (MI), hospitalization for heart failure, ischemic stroke, and late coronary revascularization (>90 days post-CMR). The secondary endpoint was a composite of cardiovascular death, nonfatal MI, and hospitalization for heart failure. The mean age was 68±11 years (49% male). Over a median follow-up time of 8.1 (IQR 5.7, 10.4) years, 55 patients experienced MACE, and 24 met the secondary endpoint. Patients with inducible ischemia had significantly greater annualized event rates for MACE (5.7% vs. 0.7%, p<0.001) and for the secondary endpoint (2.0% vs. 0.3%, p<0.001) than those without ischemia. Multivariable analysis revealed inducible ischemia as a consistent predictor for MACE (HR 3.36, 95%CI 1.90-5.94, p<0.001) and for the secondary endpoint (HR 2.89, 95%CI 1.22-6.80, p = 0.01). Late gadolinium enhancement (LGE) was an independent predictor of the secondary endpoint (HR 3.56, 95%CI 1.25-10.13; p = 0.02). Incorporating inducible ischemia and LGE data significantly improved the model's ability to discriminate MACE risk (C-statistic increase from 0.77 to 0.83; net reclassification improvement 0.42; integrated discrimination improvement 0.05). Stress perfusion CMR offers substantial independent prognostic value and effectively aids in reclassifying cardiovascular risk among prediabetic patients with suspected CAD.

Kiosk 1R-TB-03 - Safety and Outcome of Patients with Left Ventricular Thrombus Undergoing Dobutamine or Adenosine Stress Cardiac Magnetic Resonance Imaging

Kiosk 1R-TB-03 - Safety and Outcome of Patients with Left Ventricular Thrombus Undergoing Dobutamine or Adenosine Stress Cardiac Magnetic Resonance Imaging

Evaluation of Coronary Circulation by 13N-Ammonia Myocardial Perfusion Positron Emission Tomography in Patients with Right Coronary Artery Occlusion Due to Kawasaki Disease.

Although occlusion of the right coronary artery (RCA) is common in the remote stages of Kawasaki disease, revascularization of the RCA is challenging in children and is usually managed by observation without intervention. Using adenosine-stress 13N-ammonia myocardial perfusion positron emission tomography, we evaluated coronary circulation in 14 patients (12 males) with RCA occlusion to identify ischemia (myocardial flow ratio < 2.0) in the RCA region and examined hemodynamics, cardiac function, and coronary aneurysm diameter. These variables were also compared in patients with/without RCA segmental stenosis (SS). There were five cases of ischemia in the RCA region. RCA myocardial blood flow (MBF) at rest was higher in patients with ischemia than in those without ischemia, but the difference was not significant (1.27 ± 0.21 vs. 0.82 ± 0.16 mL/min/g, p = 0.2053). Nine patients presented with RCA SS, and age at onset of Kawasaki disease tended to be lower in those with SS. The maximum aneurysm diameter of RCA was significantly smaller in patients with SS (10.0 ± 2.8 vs. 14.7 ± 1.6, p = 0.0239). No significant differences in other variables were observed between patients with/without ischemia and SS. At rest, MBF in the RCA region was relatively well preserved, even in patients with RCA occlusion, and there was no progressive deterioration in cardiac function. Adenosine stress showed microcirculatory disturbances in only half of the patients, indicating that it is reversible in children with Kawasaki disease.