Myocardial Perfusion Scintigraphy Research Articles

Usability of myocardial work parameters in demonstrating myocardial involvement in INOCA patients.

Myocardial work (MW) is a novel echocardiographic modality, which has been shown to have diagnostic and prognostic values in patients with cardiovascular diseases, patients with obstructive coronary artery disease, in particular. However, only a handful of studies have examined the MW analysis in ischemia with nonobstructive coronary artery (INOCA) disease. This study, therefore, aimed to detect the early left ventricular involvement in INOCA patients diagnosed by an invasive coronary angiography performing the MW analysis. This study included a total of 119 patients with nonobstructive coronary artery disease diagnosed by invasive coronary angiography, who were checked for prior ischemia tests performing myocardial perfusion scintigraphy. Out of these 119 patients, 49 patients developed ischemia (i.e., ischemic group) diagnosed using cardiac single-photon emission computed tomography, whereas 70 patients did not (i.e., nonischemic group). The subjects were divided into three groups based on the global MW tertiles. The groups were compared in terms of the conventional, longitudinal strain, and MW findings by conducting echocardiographic examinations. The study subjects were divided into three groups based on the global constrictive work (GCW) value. The three groups were not statistically different in terms of the mean age of the patients (53.0 ± 12 vs. 52.4 ± 13.3 vs. 52.1 ± 12.3; p = 0.96). Furthermore, the three groups were not statistically different regarding the gender, height, weight, and laboratory parameters of the patients except albumin. There was no statistically difference among the tertiles of GCW groups in the measurements of cardiac chambers, LA diameter, interventricular septum, E wave, and A wave. Also, there was no statistical difference in tissue Doppler recordings. The parameters associated with MW were examined, three groups were not statistically different in terms of the global waste work (GWW) (116 ± 92, 122 ± 73, 135 ± 62, p = 0.52, respectively). In contrast, the three groups were different regarding the Global work index (GWI) (1716 ± 300, 1999 ± 130, 2253 ± 195, p < 0.001, respectively), GCW(1888 ± 206, 2298 ± 75, 2614 ± 155, p < 0.001, respectively), and Global work efficiency parameters (92.8 ± 3.6, 94.4 ± 3.2, 95.1 ± 1.8 p = 0.004, respectively). It was concluded that the MW parameters GCW and GWI may have been used for predicting INOCA in patients.

Concordance between vessel-specific and vascular territory coronary functional assessment: A comparison of quantitative flow ratio and myocardial perfusion scintigraphy.

Quantitative flow ratio (QFR) and myocardial perfusion scintigraphy (MPS) are utilized for assessing coronary artery disease (CAD) significance. We aimed to analyze their concordance and prognostic impact. We aimed to analyze the concordance between QFR and MPS and their risk stratification. Patients with invasive coronary angiography and MPS were categorized as concordant if QFR ≤ 0.80 and summed difference score (SDS) ≥ 4 or if QFR > 0.80 and SDS < 4; otherwise, they were discordant. Concordance was classified by coronary territory involvement: total (three territories), partial (two territories), poor (one territory), and total discordance (zero territories). Leaman score assessed coronary atherosclerotic burden. 2010 coronary territories (670 patients) underwent joint QFR and MPS analysis. MPSarea under the curve for QFR ≤ 0.80 was 0.637. Concordance rates weretotal (52.5%), partial (29.1%), poor (15.8%), and total discordance (2.6%). Most concordance occurred in patients without significant CAD or with single-vessel disease (89.5%), particularly without MPS perfusion defects (91.5%). Leaman score (odds ratio [OR]: 0.839, 95% confidence interval [CI]: 0.805-0.875, p < 0.001) and MPS perfusion defect (summed stress score[SSS] ≥ 4) (OR: 0.355, 95%CI: 0.211-0.596, p < 0.001) were independent predictors for discordance. After 1400 days, no significant difference in death/myocardial infarctionwas observed based on MPS assessment, but Leaman score, functional Leaman score, and average QFR identified higher risk patients. MPS showed good overall accuracy in assessing QFR significance but substantial discordance existed. Predictors for discordance included higher atherosclerotic burden and MPS perfusion defects(SSS ≥ 4). Leaman score, QFR-based functional Leaman score, and average QFR provided better risk stratification for all-cause death and myocardial infarction than MPS.

Effects of Ivabradine on Myocardial Perfusion in Chronic Angina: A Prospective, Preliminary, Open-Label, Single-Arm Study.

Ivabradine reduces heart rate (HR), episodes of angina, and nitrate consumption, and increases exercise capacity in patients with chronic angina (CA). In this exploratory study, myocardial perfusion scintigraphy (MPS) was used to evaluate changes in the percentage of myocardial ischemia after ivabradine therapy in patients with CA. This prospective, open-label, single-arm study included patients with CA receiving maximum tolerated doses of beta blockers, who had a resting HR ≥ 70bpm and had experienced ischemia according to MPS during an exercise test at baseline. Participants received ivabradine 5mg twice daily (titrated according to HR) concomitant with beta blockers. A second MPS was performed after 3months, without interruption of treatment with beta blockers or ivabradine. The primary outcome was change in the percentage of myocardial ischemia from baseline to 3months. Time to ischemia during the exercise test, the proportion of patients presenting angina during the exercise test, and health status, assessed using the seven-item Seattle Angina Questionnaire-7 (SAQ-7), were also evaluated. Twenty patients (3 females) with a mean (± standard deviation [SD]) age of 62.2 ± 6.5years were included in the study, of whom 55% had diabetes, 70% had previous myocardial revascularization, and 45% had previous myocardial infarction. The percentage of patients with myocardial ischemia significantly decreased from baseline to 3months after initiation of treatment with ivabradine (- 2.9%; 95% confidence interval [CI] - 0.3 to - 5.5; p = 0.031). Mean time to appearance of ischemia increased from 403 ± 176s at baseline to 466 ± 136s at 3 months after initiation of ivabradine (Δ62 s; 95% CI 18-106 s; p = 0.008), and the proportion of patients experiencing angina during the exercise test decreased from 40% at baseline to 5% also at 3 months (p = 0.016). Mean resting HR decreased from 76 ± 7bpm at baseline to 55 ± 8bpm at 3 months (p < 0.001). The mean SAQ-7 summary score improved from 69 ± 21 at baseline to 83 ± 12 at 3months (p = 0.001). No serious adverse effects were reported. Ivabradine added to beta blockers was associated with a reduction in detectable myocardial ischemia by MPS in patients with CA. Infographic available for this article. The trial has been retrospectively registered with the Brazilian Registry of Clinical Trials (REBEC) under the following number RBR-5fysqrh (date of registration: 30 November 2023).

Evaluation of Perfusion and Function in Cardiac Radionuclide Imaging in Cases of Heart Failure with Mid-Range Ejection Fraction

Objective: Heart failure with mid-range ejection fraction (HFmrEF) poses a significant clinical challenge due to its diverse etiology and variable prognosis. Patients with HFmrEF exhibit an intermediate level of left ventricular dysfunction, making their management and prognosis less well-defined compared to those with heart failure with reduced ejection fraction (HFrEF) or preserved ejection fraction (HFpEF). Coronary artery disease (CAD) is a common underlying cause of HFmrEF and can further exacerbate myocardial dysfunction under stress conditions. In this study, we aimed to evaluate the change in left ventricular ejection fraction with stress in the presence of coronary artery disease in cases of heart failure with mid-range ejection fraction. Material and Methods: In this retrospective study, we included 507 patients diagnosed with coronary artery disease and an left ventricular ejection fraction (LVEF) of 41-49% measured by echocardiography. All patients underwent a treadmill exercise test using the Bruce protocol, with progressively increasing speed and incline. Myocardial perfusion was assessed using stress gated myocardial perfusion scintigraphy (MPS), and fixed and reversible defects were identified in cases of coronary artery disease. Cardiac scintigraphic images were acquired from the right anterior oblique to the left posterior oblique. We calculated post-stress LVEF and the percentage decrease in LVEF to evaluate cardiac function. Results: Resting LVEF was measured as 46 (43-50), while post-stress LVEF was 35 (25-47) in all patients. Myocardial perfusion was evaluated using stress gated MPS in all patients, with 200 (39.5%) patients showing both fixed and reversible perfusion defects. The rate of decrease in LVEF due to stress was significantly higher in patients with reversible perfusion defects (15.90 (6-30.43) vs. 28.26 (24-43.18), p: 0.0005). Post-stress LVEF was lower in patients with reversible perfusion defects (40 (31-47) vs. 33 (25-38), p: 0.0005). Conclusion: In cases of impaired left ventricular perfusion, quantitative calculations of LVEF may vary, and their reliability may decrease as the ejection fraction decreases under stress conditions. Clinicians should consider this variability in the follow-up of patients with heart failure and mid-range ejection fraction.

Predicting major adverse cardiovascular events after orthotopic liver transplantation using a supervised machine learning model: A cohort study.

Liver transplant (LT) patients have become older and sicker. The rate of post-LT major adverse cardiovascular events (MACE) has increased, and this in turn raises 30-d post-LT mortality. Noninvasive cardiac stress testing loses accuracy when applied to pre-LT cirrhotic patients. To assess the feasibility and accuracy of a machine learning model used to predict post-LT MACE in a regional cohort. This retrospective cohort study involved 575 LT patients from a Southern Brazilian academic center. We developed a predictive model for post-LT MACE (defined as a composite outcome of stroke, new-onset heart failure, severe arrhythmia, and myocardial infarction) using the extreme gradient boosting (XGBoost) machine learning model. We addressed missing data (below 20%) for relevant variables using the k-nearest neighbor imputation method, calculating the mean from the ten nearest neighbors for each case. The modeling dataset included 83 features, encompassing patient and laboratory data, cirrhosis complications, and pre-LT cardiac assessments. Model performance was assessed using the area under the receiver operating characteristic curve (AUROC). We also employed Shapley additive explanations (SHAP) to interpret feature impacts. The dataset was split into training (75%) and testing (25%) sets. Calibration was evaluated using the Brier score. We followed Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis guidelines for reporting. Scikit-learn and SHAP in Python 3 were used for all analyses. The supplementary material includes code for model development and a user-friendly online MACE prediction calculator. Of the 537 included patients, 23 (4.46%) developed in-hospital MACE, with a mean age at transplantation of 52.9 years. The majority, 66.1%, were male. The XGBoost model achieved an impressive AUROC of 0.89 during the training stage. This model exhibited accuracy, precision, recall, and F1-score values of 0.84, 0.85, 0.80, and 0.79, respectively. Calibration, as assessed by the Brier score, indicated excellent model calibration with a score of 0.07. Furthermore, SHAP values highlighted the significance of certain variables in predicting postoperative MACE, with negative noninvasive cardiac stress testing, use of nonselective beta-blockers, direct bilirubin levels, blood type O, and dynamic alterations on myocardial perfusion scintigraphy being the most influential factors at the cohort-wide level. These results highlight the predictive capability of our XGBoost model in assessing the risk of post-LT MACE, making it a valuable tool for clinical practice. Our study successfully assessed the feasibility and accuracy of the XGBoost machine learning model in predicting post-LT MACE, using both cardiovascular and hepatic variables. The model demonstrated impressive performance, aligning with literature findings, and exhibited excellent calibration. Notably, our cautious approach to prevent overfitting and data leakage suggests the stability of results when applied to prospective data, reinforcing the model's value as a reliable tool for predicting post-LT MACE in clinical practice.

Comparison of Echocardiography and Myocardial Scintigraphy to Detect Cancer Therapy-Related Cardiovascular Toxicity in Breast Cancer Patients.

The mortality rate of cancer patients has been decreasing; however, patients often suffer from cardiac disorders due to chemotherapy or other cancer therapies (e.g., cancer-therapy-related cardiovascular toxicity (CVR-CVT)). Therefore, the field of cardio-oncology has drawn more attention in recent years. The first European Society of Cardiology (ESC) guidelines on cardio-oncology was established last year. Echocardiography is the gold standard for the diagnosis of CVR-CVT, but many breast cancer patients are unable to undergo echocardiography due to their surgery wounds or anatomical reasons. We performed a study to evaluate the usefulness of myocardial scintigraphy using Iodine-123 β-methyl-P-iodophenyl-pentadecanoic acid (123I-BMIPP) in comparison with echocardiography and published the results in the Journal of Imaging last year. This is the secondary analysis following our previous study. A total of 114 breast cancer patients who received chemotherapy within 3 years underwent echocardiography, as well as Thallium (201Tl) and 123I-BMIPP myocardial perfusion and metabolism scintigraphy. The ratio of isotope uptake reduction was scored by Heart Risk View-S software (Nihon Medi-Physics). The scores were then compared with the echocardiography parameters. All the patients' charts and data from January 2022 to November 2023 were reviewed for the secondary analysis. Echocardiogram parameters were obtained from 99 patients (87% of total patients). No correlations were found between the echocardiography parameters and Heart Risk View-S scores of 201Tl myocardial perfusion scintigraphy, nor those of the BMIPP myocardial metabolism scintigraphy. In total, 8 patients out of 114 (7.0%) died within 22 months, while 3 patients out of 26 CVR-CVT patients (11.5%) died within 22 months. Evaluation by echocardiography was sometimes difficult to perform on breast cancer patients. However, other imaging modalities, including myocardial scintigraphy, cannot serve as alternatives to echocardiography. Cardiac scintigraphy detects circulation disorder or metabolism disorder in the myocardium; therefore, it should be able to reveal myocardial damage to some extent. The mortality rate of breast cancer patients was higher with CVR-CVT. A new modality to detect CVR-CVT besides echocardiography can possibly be anticipated for patients who cannot undergo echocardiography.

Radionuclide Imaging Findings in Iatrogenic Stress in Cases with Reduced Left Ventricular Ejection Fraction

Objective: This study aims to contribute to the existing literature by assisting in the selection of stress protocols for patients with reduced left ventricular ejection fraction (LVEF). We also aim to provide insights into patient follow-up based on changes in post-stress LVEF determined by echocardiography. Methods: Our retrospective study encompassed 487 patients initially diagnosed with coronary artery disease. Left ventricular function was assessed using echocardiography and myocardial perfusion scintigraphy. Among them, 250 patients with LVEF values within normal limits constituted Group-1, while 237 patients with LVEF values below 50% formed Group-2. Exercise stress testing was performed using a treadmill according to the Bruce protocol. For vasodilator stress testing, intravenous adenosine infusion at a rate of 140 μg/kg/min was administered for 6 minutes. Tc-99m-sestamibi was intravenously administered (8-12 mCi) for stress imaging and (24-36 mCi) for rest imaging. Results: The median age of all patients in the study was 64 (52-79) years, with 283 (58.1%) being male. Myocardial perfusion, assessed by myocardial perfusion scintigraphy, revealed a fixed perfusion defect in all patients. Reversible perfusion defects were observed in 172 (35.3%) patients. Among patients with reduced echo-LVEF values, those who underwent exercise stress testing showed significantly lower post-stress EF values compared to those who underwent vasodilator stress testing (35 (25-42) vs. 36 (30-47), p: 0.0005). Post-stress LVEF was notably lower in patients with reversible perfusion defects, indicating a higher rate of LVEF decrease due to stress (p: 0.0005). Conclusion: Left ventricular ejection fraction (LVEF) serves as a valuable metric for assessing left ventricular function. The findings from this study support its utility in guiding the selection of a suitable stress protocol and monitoring patients during iatrogenic cardiac stress applications.

Gender differences in referral trends and clinical characteristics in the evaluation of stable coronary artery disease by myocardial perfusion scintigraphy: a 20-year analysis from a tertiary referral centre

Gender differences in referral trends and clinical characteristics in the evaluation of stable coronary artery disease by myocardial perfusion scintigraphy: a 20-year analysis from a tertiary referral centre

Predicting The Need for Revascularization in Patients with İschemia Detected by Myocardial Perfusion Scintigraphy Through P Wave Morphology

Predicting The Need for Revascularization in Patients with İschemia Detected by Myocardial Perfusion Scintigraphy Through P Wave Morphology

Evaluation of Left Ventricular Hemodynamics with Noninvasive Methods in Cases of Iron Deficiency

Objective: In this study, we aimed to evaluate the effect of iron deficiency on stress ejection fraction by assessing the change in left ventricular ejection fraction during maximum exercise in individuals with iron deficiency. Material and Methods: In this retrospective study, 212 patients, presenting with atypical chest pain and undergoing exercise gated myocardial perfusion scintigraphy, were included. Of the patients, 171 (80.7%) were female, with an average age of 50 (37-59) years. Patients were categorized into two groups: those with iron deficiency and those without. All patients exercised for a minimum of 6 minutes, reaching at least 85% of their maximum heart rate (220 - age). Hemogram, iron binding capacity, and serum ferritin values were recorded for all participants. In our study, SF less than 100 µg/L and TSAT less than 20% were considered low. Results: There was no significant difference in age and gender between the groups with and without iron deficiency (p: 0.758, p: 0.658). Echocardiography-calculated ejection fraction values were 66 (55-72). Rest ejection fraction obtained by force gated myocardial perfusion scintigraphy was 64 (52-70), and post-stress ejection fraction was calculated as 58 (50-69). The rate of decrease in post-stress EF compared to rest EF was calculated as 7.40% (7.81-19.12) in all patients. Echo, rest, and post-stress EF values in group 2 were significantly lower than those in group 1 (p: 0.003, 0.028, 0.0005, respectively). The rate of decrease in post-stress EF between the two groups was significantly higher in group 2 (p: 0.0005). Conclusion: While decreased iron stores and the presence of an iron deficiency state may be well-tolerated during daily activities, maximal exercise can exacerbate the condition if iron deficiency is underlying and undiagnosed. Early diagnosis of iron deficiency, common in society, before the onset of anemia, and prompt treatment are crucial for public health.

Cardiac Nuclear Imaging Findings in Atypical Variants of Takotsubo Cardiomyopathy

Background: In addition to the typical form resembling the classical Japanese octopus trap, atypical variants of Takotsubo cardiomyopathy (TTC) sparing the left ventricular apex have emerged over the years. The aim of this systematic review is to provide a comprehensive overview of the cardiac nuclear imaging findings in atypical variants. Methods: This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The literature research was carried out online on the Pubmed, Scopus, Central (Cochrane Library), and Web Of Science databases. Results: A total of 14 articles were ultimately selected. Myocardial perfusion scintigraphy was performed in nine studies, followed by 123I-mIBG scintigraphy, 123I-BMIPP scintigraphy, and 18F-FDG PET. In seven cases, a single cardiac nuclear imaging technique was performed, while in the remaining five and two cases, two and three different imaging modalities were, respectively, used. The most common atypical variant of our selection was the midventricular form, followed by reverse/inverted/basal TTC, with only a single case reported of a focal pattern. Conclusions: As the reason why TTC variants occur is still not clear, a deeper understanding of the current knowledge could be the basis for providing more insights into this fascinating disorder and its uncommon manifestations.

Technetium-99m Methoxyisobutyl Isonitrile Stress MPI in Suspected Coronary Artery Disease Patients: A Prospective Study to Evaluate Clinical Significance of Adenosine-induced ECG Changes

Purpose: The purpose of this study is to evaluate the adenosine pharmacological stress-induced electrocardiogram (ECG) changes and their association with stress-induced ischemic defects on myocardial perfusion scintigraphy (MPS) in the evaluation of coronary artery disease (CAD) and to evaluate event-free survival among patients with positive and negative ECG/MPS image findings. Methods: A total of 100 patients were examined using stress MPS from March 2020 to August 2021. Stress-induced ECG changes during adenosine infusion were evaluated. The summed stress score (SSS) was evaluated to identify ischemic defects in myocardium. Association of stress ECG changes and scintigraphic results was evaluated. Results: Out of 100 patients, stress ECG changes during adenosine infusion were seen among 34 patients, whereas 66 patients had normal ECG findings. Positive stress MPS findings with SSS &gt;3 were seen in 22 patients, whereas 78 patients had SSS ≤3. There was no agreement between stress ECG changes and MPS findings with Cohen’s kappa coefficient (κ) = −0.023, whereas there was mild agreement between stress ECG changes and SSS &gt;7 with κ = 0.105. Median follow-up of 11 months showed more events among patients with positive ECG changes than negative ECG changes. Conclusion: Adenosine, pharmacological stress is safe to use, but few patients might experience some minor and transient symptoms. Adenosine may induce ECG changes in patients with or without positive MPS findings. Patients with concordant positive findings need aggressive cardiac care, whereas patients with small or no defects on MPS need close monitoring.

Myocardial perfusion scintigraphy in the prediction of the existence of hemodynamically significant coronary artery stenosis

Myocardial perfusion scintigraphy in the prediction of the existence of hemodynamically significant coronary artery stenosis

INVESTIGATION OF CENTERING PROBLEM IN THE CADMIUM ZINC TELLURIDE (CZT) CARDIAC CAMERA

Introduction: Cadmium Zinc Telluride (CZT) Cardiac Cameras are a special SPECT cameras with solid state cadmium zinc telluride detectors. This diagnostic method applied in the evaluation of coronary artery disease is well designed for myocardial perfusion scintigraphy. Aim: CZT cardiac cameras have limited detector area. In patients who are morbidly obese or whose heart is not in its normal location in the body, the center of the heart and the isocenter of the device do not coincide. It is aim to investigate how these conditions affect the imaging performance of the CZT cardiac camera. Methods: A homogeneous and spherical ball with a diameter of 4 cm was used for the research. To be able to measure away from the center a wooden phantom with 8 cavities and a total length of 32 cm was designed. The center as reference point has been determined by matching the center of the device with the center of the sphere. For the next imaging, the image were taken by placing the spherical ball in the other cavities, respectively, without changing the center. Results: According to the results obtained, farther from the center, deviations from sphericity and differences in dose distribution were observed. Counts decreased by 1.5% in the 2nd position and 16% in the 3rd position relative to the center in the X-axis. A disaster area has been formed and the image area has been exited from the 4th imaging. Conclusion: It is very important to center the patient as much as possible, otherwise the doctor will misdiagnose.

99mTc-MIBI washout rate as a marker of myocardial mitochondrial dysfunction: A systematic review and meta-analysis

BACKGROUND: This review outlines the features of the pharmacokinetics of the perfusion radiopharmaceutical 99mTc-MIBI, which allows the assessment of myocardial mitochondrial dysfunction, and shows the main clinical applications of the phenomenon of increased 99mTc-MIBI washout rate. AIM: To systematize the data of fundamental (experimental) and clinical studies evaluating and estimating mitochondrial dysfunction according to myocardial perfusion scintigraphy data and perform meta-analysis of clinical studies in this field. MATERIALS AND METHODS: PubMed, Scopus, Google Scholar, and eLibrary databases were searched until mid-2023. The following keywords, their combinations, and Russian-language counterparts were used: mitochondrial dysfunction, 99mTc-MIBI, 99mTc-Tetrofosmin, myocardial perfusion scintigraphy, reverse redistribution, washout, and washout rate. In the meta-analysis, a random-effects model was used to calculate the mean difference estimate. RESULTS: Forty articles were selected for systematic analysis: 13 were experimental, 24 were original clinical papers, 2 were clinical cases, and 1 was a review. Six studies using a case–control design were selected for the meta-analyses. The total number of patients in the systematic review and meta-analysis were 551 and 196, respectively. In the analysis of the literature, the severity of the reverse redistribution phenomenon and 99mTc-MIBI washout rate correlated with mitochondrial and myocardial microstructure, left ventricular contractility and hemodynamics, natriuretic peptide levels, exercise tolerance, coronary atherosclerosis severity, myocardial oxidative metabolism, and risk of cardiovascular events. The meta-analysis showed that the washout rate was statistically significantly accelerated in individuals with cardiac pathologies, relative to controls (mean difference score, 9.5771 [95%]; confidence interval, 6.6001–12.5540; z=6.3053, p 0.0001). CONCLUSION: The assessment of mitochondrial function by 99mTc-MIBI washout evaluation may provide additional insights into the functional status of cardiac muscles.

Relation between high-sensitivity troponin I serum levels and myocardial ischemia in patients with suspected chronic coronary syndrome: The RESET-MI study

BackgroundPrevious studies showed that exercise may increase cardiac troponin serum levels; whether the occurrence of myocardial ischemia influences the changes of exercise-induced troponin raise, however, remains debatable. MethodsWe prospectively enrolled consecutive patients undergoing for the first time an elective stress myocardial perfusion scintigraphy (MPS) because of clinical suspicion of obstructive coronary artery disease (CAD). Patients were divided into 3 groups based on the evidence and degree of stress-induced myocardial ischemia at MPS: 1) group 1, no myocardial ischemia (≤4 %); 2) group 2, mild myocardial ischemia (5–10 %); 3) group 3, moderate-to-severe myocardial ischemia (≥10 %). High-sensitivity cardiac troponin I (cTnI) was measured immediately before (T0) and 1 hour (T1) and 4 h (T2) after the stress test. ResultsOne hundred-seven patients (71 males; age 65.6 ± 9.4 years) were enrolled in the study. Serum hs-cTnI concentrations (logarithmic values) significantly increased after MPS, compared to baseline, in the whole population, from 1.47±1.26 ng/L at T0, to 1.68±1.12 ng/L at T1 (p<0.001) and 2.15±1.02 ng/L at T2 (p<0.001 vs. both T0 and T1). The increase in hs-cTnI did not significantly differ between the 3 groups (p = 0.44). The heart rate achieved during the test was the strongest determinant of cTnI increase (p < 0.001) after the stress test. ConclusionsIn patients with suspected CAD, stress MPS induces an increase of cTnI that is independent of the induction and extension/severity of myocardial ischemia and is mainly related to myocardial work, as indicated by the heart rate achieved during the test.

Relation between high-sensitivity troponin i serum levels and myocardial ischemia in patients with suspected chronic coronary syndrome: the RESET-MI study

Abstract Background Previous studies showed that exercise may increase cardiac troponin serum levels; however, whether exercise-induced myocardial ischemia influences the exercise-induced increase of troponin levels remains debatable. Methods We prospectively enrolled consecutive patients undergoing an elective stress myocardial perfusion scintigraphy (MPS) because of a clinical suspicion of obstructive coronary artery disease (CAD). Patients were divided into 3 groups according to the evidence and degree of stress-induced myocardial ischemia at MPS: 1) Group 1, no ischemia (≤4% of myocardium); 2) Group 2, mild ischemia (5-10%); 3) Group 3, moderate-to-severe myocardial ischemia (≥10%). High-sensitivity cardiac troponin I (cTnI) was measured immediately before (T0) and 1 hour (T1) and 4 hours (T2) after the stress test. A successive evaluation of patients was performed at 24 months. Results One-hundred consecutive patients (64 males; age 65.5±9.5 years) were enrolled in the study. An exercise stress test and a dipyridamole stress test were performed in 81 and 19 patients, respectively. Serum hs-cTnI concentrations significantly increased after stress test, compared to baseline, in the whole population, from (median, interquartile range) 3.9 (2.5-6.1) ng/L at T0, to 4.2 (2.8-7.3) ng/L at T1 (p&amp;lt;0.001) and 6.7 (3.8-14.1) ng/L at T2 (p&amp;lt;0.001 vs. both T0 and T1). The increase in hs-cTnI did not significantly differ between the 3 groups (p=0.35; Figure). The increase was significant after both exercise (+54.5%) and dipyridamole (+18.2%), although the increase was greater after exercise (p=0.002). Heart rate achieved during the test was the strongest determinant of cTnI increase after the stress test (p &amp;lt; 0.001). Conclusions In patients with suspected CAD, stress MPS induces an increase of cTnI that is independent of the induction and severity of myocardial ischemia and is mainly related to myocardial work, as indicated by heart rate achieved during the stress test.Figure

Percutaneous coronary intervention for chronic total occlusions improves cardiopulmonary exercise capacity

Abstract Introduction Percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) is recommended in patients with an expected reduction of angina pectoris. However, whether PCI for CTO improves exercise tolerance remains controversial. Purpose To evaluate whether PCI improves cardiopulmonary exercise capacity in patients with CTO. Methods We prospectively performed both stress myocardial perfusion scintigraphy (MPS) before PCI and cardiopulmonary exercise testing (CPX) before and 6 months later of PCI in October of 2020 to September of 2022. Myocardial ischemia was defined as summed difference score ≧3. Results Of 28 patients (67.9 ± 10.6 y.o., 96% men), 31 major vessels were occluded vessels (right coronary artery 13, left anterior descending 11, and left circumflex 7). Overall, peak VO2 after PCI was higher than that before PCI (18.9 ± 4.2 vs. 17.3 ± 3.7 ml/min/kg, P &amp;lt; 0.05). Peak VO2 was improved in 20 patients and not in 8. Peak VO2 was improved in 13 of 16 patients (81%) with myocardial ischemia in the occluded area and 7 of 12 (58%) without. Conclusions PCI for CTO improves cardiopulmonary exercise capacity, especially in the patients with ischemic evidence in the occluded area.

Abstract 13494: Histopathological Analysis Indicates a Significant Role of Myocardial Perfusion Disturbance in Tissue Lesion in Chronic Chagas’ Cardiomyopathy Experimental Model

Introduction: Coronary microvascular perfusion disturbance (MPD) is frequently found in Chronic Chagas' cardiomyopathy (CCC), but its role in tissue lesion and left ventricular dysfunction progression is still unclear. Hypothesis: As MPD is associated with more severe subendocardial myocardial injury, we tested the hypothesis that histopathological changes in subendocardial layer could be quantitatively correlated to MPD in experimental model of CCC in hamsters. Methods: Female Syrian hamsters (n=23) infected with 3.5x10 4 blood trypomastigote forms of T. cruzi ( Y strain ) and their respective controls (n=6) were studied. At 8 months after infection, the animals underwent in vivo high-resolution myocardial rest perfusion scintigraphy with 99m Tc-Sestamibi and transthoracic echocardiography. After euthanasia, the myocardial tissue was processed for quantitative histopathological analysis of mononuclear infiltrate index (MII) using hematoxylin-eosin staining and myocardial fibrosis using picrosirius staining in LV wall layers: subendocardium, mesocardium and subepicardium. Results: Fourteen animals (61%) presented rest MPD. The area of MPD was negatively correlated with LVEF (R=-0.5; p=0.02), and positively correlated with LV diastolic diameter (R=0.83; p&lt;0.01). Animals with MPD exhibited increased extent of myocardial fibrosis in the subendocardial layer (0.67 + 0.18%) as compared to control animals (0.47 + 0.15%), p=0.03. However, the extent of total transmural fibrosis or fibrosis in other myocardial layers were similar among groups. The group with MPD presented higher values of MII in every myocardial layer as compared to controls and animals without MPD. However, only the MII in the subendocardial layer presented positive correlation with the extent of rest MPD (R=0.55, p=0.001). Conclusions: Our results indicate that MPD is significantly correlated with histopathological changes located in the subendocardial layer of LV walls. These results suggest that MPD may act as an amplifying and localizing factor for inflammation and fibrosis, suggesting a relevant role for myocardial hypoperfusion in the mechanisms of myocardial injury in CCC.

Comparison of the left ventricular dyssynchrony between stylet-driven and lumen-less lead technique in left bundle branch area pacing using myocardial perfusion scintigraphy.

Left bundle branch area pacing (LBBAP) has emerged as a novel physiological pacing method to reduce left ventricular (LV) dyssynchrony due to ventricular pacing. Only lumen-less pacing leads (LLLs) with fixed helixes could achieve LBBAP previously, but recently, LBBAP has been performed using stylet-driven leads (SDLs). This study aimed to evaluate the LV dyssynchrony between SDLs and LLLs techniques in LBBAP. We retrospectively evaluated patients who underwent LBBAP with either SDLs or LLLs. We compared both groups' electrocardiogram (ECG) findings and LV dyssynchrony parameters derived from myocardial perfusion scintigraphy. LV dyssynchrony parameters consisted of phase analysis and regional wall motion analysis. We evaluated bandwidth, phase standard deviation (PSD), and entropy in the phase analysis. The time to the end-systolic frame (TES) was calculated in regional wall motion analysis using single-photon emission computed tomography (SPECT). We also evaluated the maximum differences between segmental TES (MDTES), the standard deviation of TES (SDTES), and the difference in the TES between the lateral wall and septum (DTES-LS). In total, 97 patients were enrolled. The success rate of LBBAP did not differ between the groups [SDLs: 47/48 patients (98%) vs. LLLs: 47/51 patients (92%), P=0.36]. The paced QRS duration and the stimulus to the peak LV activation time (stim-LVAT) also did not differ between SDL and LLL groups (122±10 vs. 119±12 ms, P=0.206; 69±12 vs. 66±13 ms, P=0.31, respectively). There were no differences in bandwidth, PSD, and entropy between SDL and LLL groups (73°±37° vs. 86°±47°, P=0.18; 19°±8.5° vs. 21°±9.7°, P=0.19; 0.57±0.08 vs. 0.59±0.08, P=0.17, respectively). The regional wall motion analysis parameters MDTES, SDTES, and DTES-LS also did not differ between SDL and LLL groups (19%±10% vs. 20%±10%, P=0.885; 5.0%±2.5% vs. 5.0%±2.5%, P=0.995; 5.0%±3.7% vs. 4.8%±4.2%, P=0.78, respectively). LBBAP using SDLs was comparable to LV electrical and mechanical synchrony with LLLs.