Stress Cardiac Magnetic Resonance Imaging Research Articles

Development and Implementation for Patients Undergoing DSCMRs at a Free-Standing Pediatric Institution: A Collaborative Approach to Nursing Care

This article discusses the collaboration between cross-functional nursing units to develop and implement nursing care for patients undergoing dobutamine stress cardiac magnetic resonance imaging at a free-standing pediatric institution in the Midwest.

DEep LearnIng-based QuaNtification of epicardial adipose tissue predicts MACE in patients undergoing stress CMR

Background and aimsThis study investigated the additional prognostic value of epicardial adipose tissue (EAT) volume for major adverse cardiovascular events (MACE) in patients undergoing stress cardiac magnetic resonance (CMR) imaging. Methods730 consecutive patients [mean age: 63 ± 10 years; 616 men] who underwent stress CMR for known or suspected coronary artery disease were randomly divided into derivation (n = 365) and validation (n = 365) cohorts. MACE was defined as non-fatal myocardial infarction and cardiac deaths. A deep learning algorithm was developed and trained to quantify EAT volume from CMR. EAT volume was adjusted for height (EAT volume index). A composite CMR-based risk score by Cox analysis of the risk of MACE was created. ResultsIn the derivation cohort, 32 patients (8.7 %) developed MACE during a follow-up of 2103 days. Left ventricular ejection fraction (LVEF) < 35 % (HR 4.407 [95 % CI 1.903–10.202]; p<0.001), stress perfusion defect (HR 3.550 [95 % CI 1.765–7.138]; p<0.001), late gadolinium enhancement (LGE) (HR 4.428 [95%CI 1.822–10.759]; p = 0.001) and EAT volume index (HR 1.082 [95 % CI 1.045–1.120]; p<0.001) were independent predictors of MACE. In a multivariate Cox regression analysis, adding EAT volume index to a composite risk score including LVEF, stress perfusion defect and LGE provided additional value in MACE prediction, with a net reclassification improvement of 0.683 (95%CI, 0.336–1.03; p<0.001). The combined evaluation of risk score and EAT volume index showed a higher Harrel C statistic as compared to risk score (0.85 vs. 0.76; p<0.001) and EAT volume index alone (0.85 vs.0.74; p<0.001). These findings were confirmed in the validation cohort. ConclusionsIn patients with clinically indicated stress CMR, fully automated EAT volume measured by deep learning can provide additional prognostic information on top of standard clinical and imaging parameters.

The Value of a Coronary Computed Tomography Angiography plus Stress Cardiac Magnetic Resonance Imaging Strategy for the Evaluation of Patients with Chronic Coronary Syndrome.

Background: Noninvasive imaging methods, either anatomical or functional tests, serve as essential instruments for the appropriate management of patients with established or suspected coronary artery disease (CAD). We sought to evaluate the safety and efficacy of a coronary computed tomography angiography (CCTA) plus stress cardiac magnetic resonance imaging (S-CMR) strategy in patients with chronic coronary syndrome (CCS). Methods: Patients with suspected CCS showing intermediate coronary plaques (stenosis 30-70%) at CCTA underwent S-CMR. Patients with a positive S-CMR were referred to invasive coronary angiography (ICA) plus instantaneous wave-free ratio (iFR), and myocardial revascularization if recommended. All patients received guideline-directed medical therapy (GDMT), including high-dose statins, regardless of myocardial revascularization. The primary endpoint was a composite of death from cardiovascular causes, non-fatal myocardial infarction, and unplanned revascularization. Results: According to the results of CCTA, 62 patients showing intermediate coronary plaques underwent S-CMR, which was positive for a myocardial perfusion deficit in n = 17 (27%) and negative in n = 45 (73%) patients. According to the results of ICA plus iFR, revascularization was performed in 13 patients. No differences in the primary endpoint between the positive and negative S-CMR groups were observed at 1 year (1 [5.9%] vs. 1 [2.2%], p = 0.485) and after a median of 33.4 months (2 [11.8%] vs. 3 [6.7%]; p = 0.605). Conclusions: Our study suggests that a CCTA plus S-CMR strategy is effective for the evaluation of patients with suspicion of CCS at low-intermediate risk, and it may help to refine the selection of patients with intermediate coronary plaques at CCTA needing coronary revascularization.

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

Thrombotic Thrombocytopenic Purpura (TTP) Survivors Exhibit Impaired Stress Perfusion on Cardiac MRI

Introduction: Thrombotic thrombocytopenic purpura (TTP) survivors have increased rates of cardiovascular morbidity and mortality when compared with the general population. In this prospective pilot study, we sought to further characterize the long-term cardiovascular sequelae of TTP survivors through pharmacologic stress cardiac magnetic resonance imaging (CMR). Stress CMR has been increasingly utilized to detect clinical and subclinical structural and functional changes. A CMR biomarker of myocardial remodeling is extracellular volume (ECV); an increase in ECV may indicate the development of interstitial myocardial fibrosis. ECV was chosen for structural assessment as it has been implicated with diastolic dysfunction and other cardiac issues in other hematologic diseases, like sickle cell anemia. Methods: Adult patients (age ≥18 years of age) with TTP (immune-mediated or congenital) in the Ohio State University (OSU) TTP registry were prospectively consented and enrolled from March 2023 through July 2023 to undergo adenosine stress CMR at standard clinical dosing. All patients in the TTP cohort had confirmed diagnosis based on ADAMTS13 activity &amp;lt;15% during an acute episode and were in clinical remission at the time of CMR testing. Standard baseline and stress CMR parameters were obtained and compared with an age and sex matched control population, selected from patients without TTP who underwent identical stress CMR protocol for other indications and demonstrated normal stress perfusion. Patients in the control cohort predominantly had diagnoses of arrhythmia, stable angina, or heart failure. We collected data on patient demographics, details of TTP history, and underlying comorbidities. On CMR standard structural measurements were evaluated, and ECV was calculated (normal range 25.3 ± 3.5%). Perfusion was measured per standard protocols via global myocardial blood flow (MBF) as ml/min/g. Differences between the TTP and control populations were tested using the Fischer's exact test for categorical variables and Mann-Whitney U test for continuous variables. Results: A total of 10 TTP patients (9 immune-mediated, 1 congenital) were enrolled between March and July 2023. Median age at enrollment was 44.5 years (IQR 40.8-49.5) and 80% (8/10) were female. Patients were in documented clinical and ADAMTS13 activity remission with median ADAMTS13 activity of 68% (64.0-84.5), excluding the activity level of the congenital patient. Median time from initial diagnosis was 15 years (range 0.5 - 41 years) and median number of acute TTP episodes was 2 (IQR 1.0-4.5). Characteristics of the study (n= 10) and control cohort (n = 13) are summarized in Table 1. There were no significant differences in the TTP and control cohorts with respect to age, sex, race, and presence of hypertension or diabetes. Patients in the TTP cohort had significantly higher BMI (median 34.5 mg/m 2 vs 26.5 mg/m 2, p = .012), diastolic blood pressure (94 mmHg vs 82 mmHg, p = .003), and a lower rate of known cardiac disease (10% vs 85%, p&amp;lt;.001). Stress CMR showed reduced myocardial perfusion in TTP survivors: Nine out of 10 (90%) TTP survivors had evidence of structural or perfusion deficits on CMR. The median ECV in the TTP cohort (28.5%, 24.8 - 31.5) was increased compared with controls (26%, 23.5 - 27.5) though it did not reach significance (p = .08). There were no significant differences in median global MBF at rest in the TTP group (1.30, 1.16 - 1.37) compared with controls (1.18, 1.07 - 1.31, p = .210). However, TTP survivors had significantly reduced stress MBF (3.28, 2.21 - 3.53) vs controls (4.1, 3.88 - 4.22, p &amp;lt;.001) with adenosine. Reductions in quantitative stress perfusion in the TTP cohort was primarily noted in the subendocardium as shown in Figure 2. Conclusion: Asymptomatic structural changes and reduction in quantitative perfusion are common in TTP survivors. The study is ongoing to recruit more patients to ensure clinical significance and generalizability of these preliminary findings. Stress CMR may detect subclinical myocardial damage in TTP survivors who otherwise do not exhibit overt cardiovascular symptoms until a later time and may provide the basis to understand increased cardiovascular morbidity and mortality in this population.

Abstract 14155: Handgrip Exercise Provoked High Sensitivity Cardiac Troponin I Increase in Women With No Obstructive Coronary Artery Disease: Relations to Myocardial Function

Background: Among women with signs and symptoms of ischemia and no obstructive coronary arteries (INOCA) around 10% develop heart failure with preserved ejection fraction (HFpEF). Mechanisms contributing to AMI and HFpEF progression in INOCA are poorly understood. Purpose: To characterize clinical profile and stress cardiac magnetic resonance imaging (CMRI) myocardial features of INOCA patients with and without increased troponin levels in response to handgrip exercise. Methods: Women with suspected INOCA underwent cardiac MRI and invasive coronary function testing (CFT), including coronary sinus (CS) cannulation, handgrip exercise testing, and serial CS plasma sampling before, after 3 minutes of isometric handgrip stress at 30% of maximal voluntary contraction, and after 5 minutes of recovery. High sensitivity cardiac troponin I (hsTnI) was measured using commercial immunoassay (R-PLEX, Meso Scale Discovery, Rockville, MD) and compared using t-tests. Results: A total of 51 women with complete data were included, of whom 31 (60.7%) had handgrip provoked increases in hsTnI levels from baseline, while 20 (39.2%) did not. Baseline characteristics are shown in Table. Patients with increased hsTnI levels had greater impaired global longitudinal strain rates and early diastolic strain rates (radial and circumferential) compared to those without increased hsTnI. No significant differences were observed in myocardial perfusion reserve index (MPRI). Conclusion: Women with INOCA demonstrating objective evidence of handgrip exercise provoked myocardial injury exhibit evidence of myocardial dysfunction not related to myocardial perfusion. Further prospective research is needed to understand the sequence of relations between coronary microvascular dysfunction contribution to HFpEF progression.

Anatomical/Physiological Correlates of Functional Capacity in Adults With Repaired and Nonsevere Coarctation of the Aorta

BackgroundThere is limited data regarding the interplay of anatomic and physiologic parameters with exercise capacity in adults with native or recurrent nonsevere coarctation of the aorta (CoA). ObjectivesThe objective of this study was to use exercise stress echocardiography and cardiac magnetic resonance imaging to identify anatomic and physiologic correlates of exercise capacity in these patients. MethodsWe conducted a single-center retrospective analysis of 54 adults with nonsevere CoA (repaired or unrepaired) followed at our institution between 2015 and 2020. Resting coarctation gradients were obtained using echocardiography. Exercise gradients and functional capacity were assessed using exercise stress echocardiography. Aorta anatomy was obtained using magnetic resonance imaging. ResultsCoarctation-to-diaphragm ratio correlated with minutes of exercise (r = 0.56, P < 0.01) and metabolic equivalents (r = 0.49, P < 0.01). These relationships remained significant after controlling for use of beta-blockers, valvular disease, and type of coarctation repair. Minutes of exercise correlated with mean resting gradients (r = −0.39, P < 0.05). Coarctation-to-diaphragm ratio correlated with peak and mean resting gradients (r = −0.34, P < 0.05; r = −0.48, P < 0.01). Patients with coarctation-to-diaphragm ratio ≤0.7 achieved fewer metabolic equivalents (11.1 ± 1.9 vs 12.8 ± 2.2, P < 0.05) and minutes of exercise (10.3 ± 2.0 vs 12.6 ± 2.7, P < 0.05). ConclusionsIn patients with nonsevere native or recurrent CoA, reduced exercise capacity is correlated with coarctation severity by anatomic size and gradients. Those with a coarctation-to-diaphragm ratio ≤0.7 may represent a subset of patients with nonsevere CoA whose clinical symptoms are only elicited with exercise stress testing. Exercise stress testing and cross-sectional imaging may help identify those who could be considered for earlier coarctation intervention.

Cardiovascular impact of near complete estrogen deprivation in premenopausal women with breast cancer: The CROWN study

Survival with operable breast cancer has improved markedly in recent decades, however, treatment-related cardiovascular toxicities threaten to offset these gains. Ovarian function suppression paired with aromatase inhibition, for premenopausal women with hormone receptor (HR)-positive breast cancer, is a newer widely adopted therapy with the potential for significant long-term cardiovascular toxicity. Abrupt estrogen deprivation for non-cancer reasons is associated with accelerated coronary artery disease. Women with breast cancer treated with aromatase inhibition in addition to ovarian function suppression experience a dual hit with regards to estrogen exposure. The CaRdiac Outcomes With Near-complete estrogen deprivation (CROWN) study seeks to understand the early, subclinical natural history of cardiovascular compromise in young women undergoing near-complete estrogen deprivation (NCED) therapy. It is critical to understand the early subclinical development of cardiovascular disease to identify a window for therapeutic intervention before overt cardiovascular events occur. This three-site regional study (Atrium Health Wake Forest, Duke, and Virginia Commonwealth University) uses serial stress cardiac magnetic resonance (CMR) imaging and cardiac computed tomography angiography (CCTA) obtained during the initial two years of NCED therapy to study myocardial prefusion reserve (MPR), large cardiovascular vessel changes, left ventricular function, and other cardiovascular parameters. The CROWN cohort will consist of 90 premenopausal women with breast cancer, 67 with HR-positive disease receiving NCED and 23 comparators with HR-negative disease. Participants will undergo three annual CMR scans and two CCTA scans during the two-year study period. After initial activation hurdles, accrual has been brisk, and the study is expected to complete accrual in December 2024. Efforts are in place to encourage participant retention with the study primary outcome, change in MPR between the two groups, to be reported in 2026-2027. The results of this study will enable premenopausal women with breast cancer to balance the health burdens of cancer at a young age and treatment-related cardiovascular morbidity. Finally, the tools developed here can be utilized to study cardiovascular risk across a range of cancer types and cancer therapies with the ultimate goals of both developing generalizable risk stratification tools as well as validating interventions which prevent overt cardiovascular compromise.

Safety and clinical impact of adenosine stress perfusion cardiac magnetic resonance in Asian patients with known or suspected coronary artery disease.

Adenosine stress cardiac magnetic resonance (CMR) imaging is increasingly utilized for evaluating patients with known or suspected coronary artery disease (CAD). This study aims to assess the safety and clinical impact of adenosine stress CMR in a tertiary care setting in Thailand. A total of 3,768 consecutive patients aged 18 years and above who underwent adenosine stress CMR between 2017 and 2020 were included in the study. Patient records were reviewed to collect data on clinical characteristics, hemodynamic measurements, complications during or immediately after CMR, and the rates of clinical changes resulting from CMR. Among the included patients, the primary indications for adenosine stress CMR were risk stratification in suspected CAD (70.8%) and the assessment of myocardial ischemia/viability in patients with known CAD (26.5%). There were no reported deaths or acute myocardial infarctions during the procedure. Major complications, specifically acute pulmonary edema requiring hospital observation or admission for further management, occurred in four patients (0.11%), all of whom were elderly (ranging from 75 to 91 years) with a history of heart failure. Non-major complications were observed in 13.7% of patients, with dyspnea (9.8%) and mild chest pain (5.6%) being the most common. CMR provided a completely new diagnosis in 26.2% of patients. Overall, stress CMR resulted in a change in diagnosis or management for 48% of patients. Adenosine stress CMR was found to be safe and to have a significant impact on clinical management in Asian patients with known or suspected CAD. These findings support the use of adenosine stress CMR as a valuable tool for evaluating and guiding treatment decisions in this patient population.

Prognostic value of negative stress cardiac magnetic resonance imaging in patients with moderate-severe coronary artery stenosis.

This study aims to evaluate the prognostic value of stress cardiac magnetic resonance (CMR) without inducible ischemia in a real-world cohort of patients with known severe coronary artery stenosis. The prognosis of patients with severe coronary artery stenosis and without inducible ischemia using stress CMR remains uncertain, even though its identification of functionally significant coronary artery disease (CAD) is excellent. Patients without inducible ischemia and known CAD who underwent stress CMR between February 2015 and December 2016 were included in this retrospective study. These patients were divided into two groups: group 1 with stenosis of 50%-75% and group 2 with stenosis of >75%. The primary endpoint was defined as the occurrence of a major adverse cardiovascular event (MACE) [cardiac death, non-fatal myocardial infarction (MI), percutaneous coronary intervention (PCI), or coronary artery bypass grafting (CABG)]. Real-world data collected from 169 patients with a median age of 69 (60-75) years were included. The median follow-up was 5.5 (IQR 4.1-6.6) years. Events occurred after a mean time of 3.0 ± 2.2 years in group 1 and 3.7 ± 2.0 years in group 2 (p = 0.35). Sixteen (18.8%) patients in group 1 and 23 (27.4%) patients in group 2 suffered from MACE without a significant difference between the two groups (p = 0.33). In group 2, one cardiac death (1.2%), seven non-fatal MI (8.3%), 15 PCI (17.9%), and one CABG (1.2%) occurred. The findings of this pilot study suggest that long-term outcomes in a real-world patient cohort with known severe and moderate coronary artery stenosis but without inducible ischemia were similar. Stress CMR may provide valuable risk stratification in patients with angiographically significant but hemodynamically non-obstructive coronary lesions.

Exercise stress cardiac magnetic resonance imaging in the assessment of induced cardiovascular responses in cardiac patients: a scoping review protocol.

This scoping review will describe cardiac magnetic resonance imaging testing protocols used in combination with exercise (Ex-CMR) to assess cardiovascular responses. The review will document the advantages and limitations of these protocols in cardiac patients. Ex-CMR characterizes the heart, differentiating between normal and pathological cardiac remodeling with considerable accuracy. However, there is no review detailing existing Ex-CMR protocols. This is particularly important since not all Ex-CMR protocols seem to induce enough stress to effectively characterize cardiac remodeling, hence the need for a review to report on the current evidence. This review will consider studies that use Ex-CMR testing protocols to assess cardiovascular responses, revealing cardiac remodeling in patients whose age at the time of the study was ≥ 18 years. The review will be conducted in accordance with the JBI methodology for scoping reviews and reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). The following databases will be searched: PubMed, Embase, ISI Web of Science, OpenGrey, Grey Matters, and OAlster. Articles in English and French will be included and there will be no limitation set for the date of publication. Data will be extracted from papers included in the scoping review by 2 independent reviewers and will be classified in summary tables. Open Science Framework https://osf.io/hvn75/?view_only=f6cf8fc2112e498d89c39639dbce70d1 .

Safety, accuracy, and prediction of prognosis in patients with end-stage chronic kidney disease undergoing dobutamine stress cardiac magnetic resonance imaging.

Advanced chronic kidney disease (CKD) is an independent risk factor for coronary artery disease (CAD). Due to its unique uremia-derived pathophysiology of atherosclerosis and the limitations of using potentially harmful contrast agents, the best non-invasive approach to assess CAD in these patients remains unclear. We sought to investigate the accuracy, safety, and prognosis of patients with severe CKD undergoing dobutamine stress cardiac magnetic resonance imaging (CMR). In this retrospective, single-center study, patients on dialysis or with a glomerular filtration rate of <15 ml/min/1.73 m2 who underwent dobutamine stress CMR were included. A rest and stress wall motion analysis was performed using dobutamine/atropine as stressor. The target heart rate was 85% of the maximum heart rate. Periprocedural adverse events and 1-year follow-up data were obtained. A total of 176 patients (127 men, 49 women) with a mean age of 60.9 ± 14.7 years were included, of which 156 patients were on permanent dialysis. Short-term symptoms such as angina or shortness of breath during stress CMR were frequent (22.1%), but major complications were rare (one patient with myocardial infarction, 0.6%). The 1-year event rate was high (16.4%) with a significant independent correlation to reduced ejection fraction at rest (p = 0.037) and failure to achieve the target heart rate (p = 0.029). The overall accuracy for predicting significant CAD was good (sensitivity of 71.4%, specificity of 98.4%) and excellent if the target heart rate was achieved (83.3%, 97.9%). A negative stress CMR was highly predictive for the absence of major adverse cardiac event or any coronary revascularization during the 1-year follow-up (negative predictive value of 95.0%). Dobutamine stress CMR is a safe and accurate diagnostic imaging technique in patients at advanced stages of chronic kidney disease. A reduced ejection fraction and the inability to reach the target heart rate are independent predictors of a poor outcome.

Tolerability and efficacy of a reduced dose adenosine stress cardiac magnetic resonance protocol under general anesthesia in infants and children.

Intravenous adenosine induces pharmacological stress by causing vasodilatation and thus carries the risk of severe hypotension when combined with vasodilatory effects of anesthetic agents. This study describes our experience with a reduced dose adenosine cardiac magnetic resonance imaging (MRI) protocol in young children under general anesthesia (GA). This is a retrospective report of all patients from birth to 18years who underwent adenosine stress cardiac MRI under GA between August 2018 and November 2022. Based on our anecdotal experience of severe adverse effects in patients receiving adenosine infusion under GA and in discussion with the pediatric anesthesia team, we developed a modified protocol starting at a dose of 110 mcg/kg/min with incremental escalation to a full dose of 140 mcg/kg/min to achieve desired hemodynamic effect. Twenty-two children (mean age 6.5years, mean weight 28kg) satisfied the inclusion criteria. The diagnoses included Kawasaki disease (7), anomalous aortic origin of left coronary artery (3), anomalous aortic origin of right coronary artery (2), coronary fistula (3), repaired d-transposition of great arteries (2), repaired anomalous left coronary artery from pulmonary artery (2), repaired truncus arteriosus with left coronary artery occlusion (1), extracardiac-Fontan with left coronary artery myocardial bridge (1), and post heart transplantation (1). Nine patients needed dose escalation beyond 110 mcg/kg/min. Two patients had transient hypotension during testing (systemic blood pressure drop > 25mmHg). No patient developed significant heart block or bronchospasm. Six patients (repeat study in one) demonstrated inducible perfusion defects (27%) on stress perfusion sequences-5 of whom had confirmed significant coronary abnormalities on angiography or direct surgical inspection. A reduced/incremental dose adenosine stress cardiac MRI protocol under GA in children is safe and feasible. This avoids severe hypotension which is both unsafe and may result in inaccurate data.

Association between fractional flow reserve and CMR-derived exercise capacity

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): NMRC Open-Fund Young Individual Research Grant, Singapore. NMRC Open-Fund Individual Research Grant, Singapore. Background In-scanner exercise stress cardiac magnetic resonance (ExCMR) imaging using supine cycling ergometer offers assessment of perfusion defects, inducible regional wall motion abnormalities, viability and exercise capacity in a single examination (EMPIRE Trial). Aim We aim to investigate the role of CMR-derived exercise capacity to assess the physiological stenosis severity, measured by invasive fractional flow reserve (FFR). Methods 107 patients (60±8 years, 80 males) with suspected coronary artery disease (CAD) underwent ExCMR (Siemens 1.5T) and invasive coronary angiogram with FFR measurement (PressureWireTMX Guidewire – Abbott Laboratories) followed previously published trial protocol [1]. Exercise capacity was derived as age- and sex-specific percentile of peak cardiac index, according to the reference range previously established [2]. Results Exercise capacity remains the only predictor of FFR values (beta 0.005, P&amp;lt;0.001) with backward multivariate regression of clinical variables (age, sex, BMI, presence of hyperlipidema, blood pressure, presence of diabetes mellitus) and quantitative CMR parameters (LV mass, extracellular volume, LV stroke volume at rest and exercise capacity). Patients with haemodynamically significant CAD (FFR&amp;lt;0.8) had significantly lower exercise capacity (median 14 [IQR 4–20] vs 5 [IQR 1–10] age- and sex-specific percentile of peak cardiac index, P&amp;lt;0.001) Conclusion In addition to perfusion defects, regional wall motion abnormalities and viability assessment to detect coronary artery disease, exercise capacity predicts the physiological stenosis severity.

Preliminary results of whole exome sequencing in a clinical hypertrophic cardiomyopathy cohort in India

Abstract Funding Acknowledgements Type of funding sources: None. Background Hypertrophic cardiomyopathy (HCM), characterized by unexplained left ventricular hypertrophy and outcomes ranging from normal life expectancy to heart failure and sudden cardiac death, has a global prevalence of about 1 in 500. Genetic testing helps to improve care of patients with HCM and their family members as children of carriers have a 50% chance of inheriting the disease. However, there is limited availability, awareness and application of genetic testing modalities, particularly whole exome sequencing (WES), in the management of HCM in India. Purpose This study aimed to analyze the results of WES in a clinical HCM cohort in India. Methods Patients with unexplained moderate to severe cardiomyopathy presenting to our centre from 2017 to 2022 and consenting for genetic testing were included in the study. Following a thorough clinical diagnostic process including 3-generational family history, electrocardiogram and echocardiogram in all patients and exercise stress test, Holter monitoring and cardiac magnetic resonance imaging where applicable, pre-test counseling was provided and WES performed using genomic DNA isolated from whole blood samples. A total of 33 affected individuals including 1 affected family member from 32 families were processed for genetic testing. A multidisciplinary team comprising of cardiologist, cardiothoracic surgeon, physician with expertise in cardiogenetics, geneticist and genetic counselor carried out the study in a tertiary cardiac centre. Results Age of the probands (n=32) at the time of the study was 47.8±15.9 years and 24 (75%) were males. There was concomitant hypertension in 11 (34%), type 2 diabetes mellitus in 6 (19%), arrhythmias in 6 (19%) and coronary artery disease in 2 (6%) probands. Obstructive HCM was present in 2 (6%) probands. Disease-causing significant variants (Pathogenic/Likely pathogenic) were detected in 8 (25%, Table), variants of uncertain significance in 17 (53%) and no significant variants were detected in 7 cases. Cascade genetic testing of significant variants among 7 family members of 4 probands showed segregation of the pathogenic variant in 4 asymptomatic carriers. Conclusions The yield of whole exome sequencing in a clinical HCM cohort in India was 25%. Of note the rare variants of uncertain significance in the cardiomyopathy genes makes genetic counseling and disease management challenging. However, large-scale studies in the context of Indian population are expected to bring clarity on the role of these variants in disease manifestation. A multidisciplinary team approach incorporating genetic testing modalities such as whole exome sequencing and cascade screening is the way forward in the comprehensive management of patients with HCM and their families.

Coronary Computed Tomography vs. Cardiac Magnetic Resonance Imaging in the Evaluation of Coronary Artery Disease

Coronary artery disease (CAD) represents a widespread burden to both individual and public health, steadily rising across the globe. The current guidelines recommend non-invasive anatomical or functional testing prior to invasive procedures. Both coronary computed tomography angiography (cCTA) and stress cardiac magnetic resonance imaging (CMR) are appropriate imaging modalities, which are increasingly used in these patients. Both exhibit excellent safety profiles and high diagnostic accuracy. In the last decade, cCTA image quality has improved, radiation exposure has decreased and functional information such as CT-derived fractional flow reserve or perfusion can complement anatomic evaluation. CMR has become more robust and faster, and advances have been made in functional assessment and tissue characterization allowing for earlier and better risk stratification. This review compares both imaging modalities regarding their strengths and weaknesses in the assessment of CAD and aims to give physicians rationales to select the most appropriate modality for individual patients.

Coronary microvascular dysfunction as assessed by angiography-derived index of microvascular resistance co-localizes with and may explain the presence of ischemia in stress-cardiac magnetic resonance imaging in the absence of coronary artery disease.

Ischemia with no obstructive coronary disease (INOCA) is a frequent phenomenon in the cath lab. A possible cause is coronary microvascular dysfunction (CMD), which may be assessed by invasive testing with possible complications; therefore, less invasive approaches have emerged, such as the angiography-derived index of microvascular resistance (aIMR). The aim of our study was to investigate the association of single-vessel aIMR as a measure of CMD with areas of INOCA in stress testing. We measured aIMR in 286 vessels from 102 patients undergoing both stress cMRI and coronary angiography. Groups were (a) INOCA group (93 vessels, 32 patients); (b) coronary artery disease (CAD) control group (116 vessels, 42 patients) with ischemia due to relevant stenosis; and (c) control group (77 vessels, 28 patients) without ischemia or relevant stenosis. INOCA patients presented higher mean aIMR (28.3 ± 5.7) compared to both CAD patients (17.4 ± 5.7, p < 0.001) and controls (22.1 ± 5.9, p < 0.001). Furthermore, in INOCA patients aIMR was significantly increased (33.0 ± 8.1 vs. 25.8 ± 6.3, p = 0.021) in vessels with vs. without ischemia. Single vessel aIMR presented a very good diagnostic efficiency in detecting INOCA [AUC 0.865 (0.804-0.925), optimal cut-off 27.1, p < 0.001]. CMD, as assessed by 3-vessel aIMR, co-localizes with and may explain the presence of ischemia in stress-cMRI in INOCA.

Prognostic value of stress cardiac magnetic resonance at 3 Tesla in patients with known or suspected coronary artery disease

Abstract Background Adenosine stress cardiac magnetic resonance imaging (adenosine stress CMR) is increasingly playing a role in the non-invasive test for the diagnosis of coronary artery disease (CAD). But there are limited data on the prognostic value of predicting CAD-related death and major cardiac events (MACE) by adenosine stress CMR at 3 Tesla in Thailand. Objectives This study aimed to assess the prognostic value of adenosine stress CMR at 3 Tesla to predict CAD-related death, MACE, and all-cause mortality during two years in patients with known or suspected CAD. Methods This is a single-center retrospective cohort study in patients with suspected or known CAD who underwent adenosine stress CMR at 3 Tesla between 1 September 2017 to 31 August 2019 at our hospital. The data were collected from electronic medical record reviews. Only patients who completed two years of follow-up or had events were included in this study. Results A total of 633 patients were analyzed (age 66.21±12.60 years, 53.7% male, 31.9% known CAD), within two years of follow-up, we observed 15 deaths (2.4%) occurred with 5 CAD-related death (0.8%) and 10 non-fatal myocardial ischemia (non-fatal MI) (1.6%). The presence of ischemia in adenosine stress CMR at 3 Tesla is associated with CAD-related death, but the events rates of acute MI are about the same in both groups (1.4% vs. 1.7%). Patients who underwent CAG after CMR were analyzed and categorized into normal coronary arteries, insignificant CAD, and significant CAD groups. Divided the positive adenosine stress CMR group to 6.8%, 7.7%, 85.5%, and the negative adenosine stress CMR group to 15.4%, 38.5%, 42.6%, respectively. So, the adenosine stress CMR at 3 Tesla has sensitivity at 94.34%, Specificity 29.17%, PPV 85.47%, and NPV 53.85%. Conclusions In this cohort study, patients with positive adenosine stress CMR were associated with an increased risk of CAD-related death. High-risk patients who received revascularization had a good prognosis as those with a negative adenosine stress perfusion CMR. Therefore, adenosine stress CMR at 3 Tesla is an effective tool with high sensitivity and positive predictive value for identifying high-risk patients for further treatment and procedures. Funding Acknowledgement Type of funding sources: None.

Characterizing left ventricular stiffness in women with signs and symptoms of ischemia with no obstructive coronary arteries

Abstract Background Women with signs and symptoms of ischemia and no obstructive coronary arteries (INOCA) have evidence of diastolic dysfunction and are at increased risk of developing heart failure with preserved ejection fraction (HFpEF). However, mechanisms contributing to HFpEF development are poorly understood and often attributed to underlying cardiovascular risk factors. Purpose To compare clinical, invasive, and imaging parameters in women with suspected INOCA and various degrees of left ventricular (LV) stiffness (as measured by invasive end-diastolic pressure [EDP]/end diastolic volume [EDV]). Methods Women with suspected INOCA underwent invasive LV pressure-volume loop analysis at rest and coronary function testing with a Doppler wire in the left anterior descending artery. Intracoronary vasoactive substances (adenosine, acetylcholine, nitroglycerin) were infused into the left main artery, as published. Rest and adenosine stress cardiac magnetic resonance (CMR) imaging was performed to evaluate LV function, structure, perfusion, and fibrosis. Women in different tertiles of EDP/EDV ratio were compared using t-tests. Results A total of 62 women with complete invasive data were included; 2 did not complete CMR. Compared to the lower EDP/EDV tertile, women in the upper tertile were older, had higher ejection fraction, higher mass/volume ratio, worse diastolic function, greater aortic stiffness and worse coronary microvascular function (Table 1). Traditional cardiovascular risk factors were not significantly different. Conclusion Among women with INOCA, older age, coronary microvascular dysfunction, and aortic stiffness were related to greater LV stiffness at rest. Those with the highest EDP/EDV ratio had hyperdynamic LV systolic function and the smallest LV size. More work is needed to understand contribution of coronary microvascular dysfunction to HFpEF progression. Funding Acknowledgement Type of funding sources: Other. Main funding source(s): National Institutes of HealthErika Glazer Women's Heart Health Project

Association between severity of ischemia evaluated by stress CMR and Syntax score in patients with stable coronary artery disease

Abstract Dipiridamol stress cardiac magnetic resonance (CMR) had proved to be useful to evaluate the benefit of revascularization in stable coronary artery disease [1]. Nevertheless the association between stress CMR imaging parameters and coronary Syntax score has not yet be fully evaluated. Objective To analyze the association of the extent and transmurality of ischemia and necrosis analyzed by vasodilators stress CMR with the severity and prognosis of coronary artery disease assessed by the Syntax score. Methods A retrospective cohort study including consecutive patients with stable coronary artery disease with inducible ischaemia in vasodilators stress CMR who underwent post-study catheterization was performed. The CMR protocol includes a functional study with b-SSFP sequences, first-pass perfusion with b-SSFP sequences obtained after administration of 0.84mg/kg of dipyridamole and during administration of gadolinium chelates and also IR-FGE viability sequences. A post-stress perfusion (PSP) and viability (V) score was developed scoring each segment from 0 to 2 according to transmurality. The number of segments with induced wall motion abnormalities (NSIWA) were also analyzed. The Syntax I and II scores were calculated using data from coronary angiography and computerized medical records. Results 208 patients were included, mean age 65±13 years, 44% women, 109 of them revascularized after stress CMR, 13 of them by surgery. Univariate analysis showed a significant correlation of the PSP, NSIWA and V scores with the Syntax I and Syntax 2. Using a multivariate regression models, NSIWA and V scores were independent predictors for Syntax I while NSIWA and PSP were independent predictors for Syntax 2. Conclusions – CMR stress test in patients with stable coronary artery disease allows an integrative assessment of V, PSP and PSWA and all of this parameters were associated with the severity of coronary artery disease and the prognosis after revascularization estimated by the Syntax I and 2. – NSIWA and V independently predict the severity of coronary artery disease estimated using Syntax I. – NSIWA and PSP independently predict prognosis after revascularization estimated for surgery using Syntax 2. Funding Acknowledgement Type of funding sources: None.