Assessment of Myocardial Perfusion and Systolic Function in Patients with Coronary Artery Disease after Coronary Artery Bypass Surgery by Myocardial Contrast Echocardiography and Two-dimensional Strain Echocardiography

The clinically applied value of myocardial perfusion and systolic function in patients with coronary artery disease after coronary artery bypass surgery using real-time myocardial contrast echocardiography （RT-MCE） combined with two-dimensional strain echocardiography was assessed. Twenty patients underwent intravenous RT-MCE by intravenous injections of SonoVue before and after coronary artery bypass surgery. Two-dimensional images were recorded from the left ventricular four-chamber view, two-chamber view and the apical view before, and two weeks and three months after coronary artery bypass surgery, and the peak systolic longitudinal strain was measured. The results showed that myocardial perfusion was significantly increased after coronary artery bypass surgery in about 71.6% segments. In the group that myocardial perfusion was improved, the peak systolic longitu- dinal strain three months after bypass surgery was significantly higher than that before operation [（-15.78±5.91）% vs （-10.45±8.31）%, P〈0.05]. However, the parameters did not change in the group without myocardial perfusion improvement [（-10.33±6.53）% vs （-9.41±6.09）%, P〉0.05]. It was concluded that whether or not the improvement of myocardial perfusion can mirror the recovery trend of regional systolic function, two-dimensional strain echocardiography can observe dynamic change of regional systolic function. The combination of myocardial perfusion with two-dimensional strain echocardiography can more accurately assess the curative effectiveness of coronary artery bypass surgery.

Revascularization and outcomes in Veterans with moderate to severe ischemia on myocardial perfusion imaging

Background: The prevalence of ischemia on nuclear myocardial perfusion imaging(MPI) has been decreasing. Recent research has questioned the benefit of invasive revascularization for patients with moderate to severe ischemia. We hypothesized that patients with moderate to severe ischemia could routinely undergo successful revascularization.Methods: We analyzed data from 544 patients who underwent an MPI at a single academic Veterans Affairs Medical Center. Patients with moderate to severe ischemia, defined as a summed difference score(SDS) 8 or greater, were compared to the rest of the cohort.Results: Of the total cohort(n=544), 39 patients had MPI studies with resultant moderate to severe ischemia. Patients with ischemia were more likely to develop coronary artery disease(74.4% versus 38.8%, P<0.0001) and have successful revascularization(38.5% versus 4.0%, P<0.0001) during the following year. Revascularization was attempted in 31 patients with moderate to severe ischemia, though only 15(47%) of these attempts were successful. Ischemia was predictive of myocardial infarction(5.1% versus 0.8%, P=0.01) within 1 year.Conclusion: Moderate to severe ischemia is an uncommon finding in a contemporary nuclear laboratory. Among patients with ischemia, revascularization is typically attempted but is frequently unsuccessful.Trial registration: This trial does not appear on a registry as it is neither randomized nor prospective.

Diagnosing CAD: additional markers from myocardial perfusion SPECT

Over the past decades, stress/rest myocardial perfusion SPECT （MPS） has been utilized as a standard modality for the diagnosis, risk stratification and prognostic assessment of coronary artery disease （CAD）. In addition to the perfusion information, MPS can also provide functional information of the left ventricle, including volume, ejec- tion fraction, wall motion and dyssynchrony. This article introduces the incremental value of these non-perfusion parameters as markers and prognosticators of CAD.

Thrombus aspiration plus intra-infarct-related artery administration of tirofiban improves myocardial perfusion during primary angioplasty for acute myocardial infarction

Background We developed a new combined strategy of thrombus aspiration plus intra-infarct-related artery （IRA） bolus administration of tirofiban via the aspiration catheter in patients with ST-segment elevation myocardial infarction （STEMI）. This strategy can reduce the distal embolism and achieve highly localized concentrations of tirofiban, which can improve myocardial reperfusion without increasing the risk of bleeding. The aim of this study was to investigate whether this combined strategy is superior to thrombus aspiration alone in improving myocardial perfusion in patients with STEMI undergoing primary angioplasty.Results Baseline characteristics of the two groups were well-balanced. The TIMI 3 flow showed a better tendency in the intra-IRA group than in the aspiration alone group （97.22% vs. 87.04%, X2=7.863, P=0.049）. The peak of CK-MB （83.9 （68.9-310.5） U/L vs. 126.1 （74.7-356.7） U/L, P=0.034） and Tnl （42.7 （14.7-113.9） ng/ml vs. 72.5 （59.8-135.3） ng/ml, FMD.029） were lower in the intra-IRA group than in the aspiration alone group. LVEF in the hospital favored the intra-IRA group, （45.7±8.3）% to （42.9±12.1）%, t=1.98, P=0.049. There was a tendency towards a lower MACE at 9-month follow-up in the intra-IRA group although it did not reach statistical difference （Log-rank X2=2.865, P=0.09）. There was no statistical difference in any bleeding events between the two groups.Conclusions Thrombus aspiration plus intra-IRA bolus administration of tirofiban combined with angioplasty may be related with improved myocardium perfusion, saved more myocardium, and resulted in a better clinical prognosis.

Effect of Chinese Drugs for Supplementing Qi,Nourishing Yin and Activating Blood Circulation on Myocardial Perfusion in Patients with Acute Myocardial Infarction after Revascularization

Objective:To observe the effects of Chinese drugs for supplementing qi,nourishing yin and activating blood circulation on the myocardial perfusion in acute myocardial infarction(AMI) patients after revascularization.Methods:Eighty patients with anterior or inferior ventricular wall AMI,who had received revascularization by intravenous thrombolysis or coronary bypass,were randomized into the treated group and the control group equally,both treated with conventional Western medical treatment,but combined,resp...

Coronary tortuosity is associated with reversible myocardial perfusion defects in patients without coronary artery disease

Coronary artery disease （CAD） is the leading cause of cardiovascular death in the Chinese population.Coronary angiography is the golden standard for the diagnosis of CAD and coronary tortuosity （CT） is a common coronary angiographic finding, however, little work has been done on clinical manifestation and significance of CT. It was hypothesized that CT may be associated with angina pectoris and abnormal exercise stress test in patients without CAD, but weather CT can lead to cardiac ischemia has not yet been clarified. The purpose of this study was to determine the impact of CT on myocardial perfusion detects.

Quantitative Analysis of Myocaridal Perfusion in Rabbits by Tansthoracic Real-time Myocardial Contrast Echocardiography

To evaluate the feasibility of real-time myocardial contrast echocardiography （RTMCE） by quantitative analysis of myocardial perfusion in rabbits, transthoracic RTMCE was performed in 10 healthy rabbits by using continuous infusion of SonoVue into the auricular vein. The short axis view at the papillary muscle level was obtained. The duration of the time that the contrast took to appear in right heart, left heart and myocardium was recorded. The regional myocardial signal intensity （SI） versus re-filling time plots were fitted to an exponential function： y（t） =A（1–e–β（t–t0）） ＋ C, where y is SI at any given time, A is the SI plateau that reflects myocardial blood volume, and β is the slope of the refilling curve that reflects myocardial microbubble velocity. The A, β and A×β values at different infusion rate of SonoVue were analyzed and the A, β and A×β values in each segment in the short axis view at the papillary muscle level were compared. All the animal experiments were successful and high-quality im-ages were obtained. The best intravenous infusion rate for SonoVue was 30 mL/h. The contrast appeared in right heart, left heart and myocardium at 7.5±2.2 s, 9.1±2.4 s and 12.2±1.6 s respectively. After 16.6±2.3s, myocardial opacification reached a steady state. The mean A, β and A×β value in the short axis view at the papillary muscle level were 9.8±3.0 dB, 1.4±0.5 s-1 and 13.5±3.6 dB×s-1 respectively. A, β and A×β values showed no significant differences among 6 segments. It was suggested that RTMCE was feasible for quantitative analysis of myocardial perfusion in rabbits. It provides a non-invasive method to evaluate the myocardial perfusion in rabbit disease models.

Myocardial perfusion imaging with a contrast agent at a low concentration in the diagnosis of myocardial infarction in the elderly

Objective To evaluate the clinical value of myocardial perfusion imaging with dual-source dual-energy CT and a contrast agent at a low concentration in the diagnosis of myocardial infarction in the elderly.Methods Onestop cardiac imaging with dual-source CT was conducted in 138 elderly patients diagnosed with myocardial infarction between October 2015 and May 2016.The

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

BACKGROUND 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.AIM To assess the feasibility and accuracy of a machine learning model used to predict post-LT MACE in a regional cohort.METHODS 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.RESULTS 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.CONCLUSION 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.

Reduced Heart Rate Response during Drug-Induced Stress Is Related to the Severity of Perfusion Defect

Introduction: During the pharmacological stress test with dipyridamole, a normal hemodynamic response is slightly reduced blood pressure and raised heart rate (HR). However, sometimes the HR response is reduced. This study investigated the relationship between the HR response during the dipyridamole stress test and the severity of the perfusion defects using Thallium 201 myocardial perfusion imaging. Methods: We enrolled 50 patients undergoing dipyridamole stress at the nuclear cardiology Lab, Main University Hospital of Alexandria. Standard dipyridamole protocol (infusion over 4 min) and standard thallium 201 protocol (2 min after dipyridamole infusion) were followed. If the heart rate (HR) ratio (peak HR/rest HR) was 1.20 or less, it was considered a reduced response. Total perfusion defect (TPD), summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) for myocardial perfusion were calculated. Patients with reduced HR response and normal HR responses were compared and independent predictors of reduced HR response were determined. Results: About 56% of patients had reduced HR response;which included a high number of patients with a history of dyslipidemia and diabetes mellitus. The reduced HR response group showed lower SSS, SRS. The analysis showed that the independent predictors of reduced HR response were rest HR, SSS, and diabetes mellitus. Conclusions: Reduction in the HR response during the dipyridamole-induced stress test is related to the severity of perfusion defect, diabetes mellitus, and Dyslipidemia.

A New Approach to the Presentation of Myocardial SPECT Images——Radial Slices——Data Reduction without Loss of Information

Objective: SPECT data from myocardial perfusion imaging (MPI) are normally displayed as a set of three slices orthogonal to the left ventricular (LV) long axis. For data presentation, the images are orientated about the LV long axis. Therefore, radial slices provide a suitable alternative to standard orthogonal slices, with the advantage of requiring fewer slices to adequately represent the data. In this study, a semi-automatic method is developed for displaying MPI SPECT data as a set of radial slices orientated about the LV axis. The aim is to reduce the number of slices viewed without loss of information and independently from the heart size. Method: Standard short axis slices, orientated perpendicular to the LV axis, are utilized.The skeleton of the segmented myocardium is found and the true LV axis is determined in each central long slice. The LV axis of the whole volume is determined by aligning the axes of all slices. Result: Radial slices centered about this axis were generated by integration over a sector equal to the resolution of the imaging system which was of the order of 1.2 cm. Therefore, assuming a mean LV diameter of 8 cm, 20 slices were sufficient to represent a non-gated study. Gated information could be adequately displayed with 4 slices integrated over an angle of 45. Conclusion: A semi-automatic method for generating radial slices from SPECT MPI short axis slices has been developed.

Comparison between multiple logistic regression and machine learning methods in prediction of abnormal thallium scans in type 2 diabetes

BACKGROUND The prevalence of type 2 diabetes(T2D)has been increasing dramatically in recent decades,and 47.5%of T2D patients will die of cardiovascular disease.Thallium-201 myocardial perfusion scan(MPS)is a precise and noninvasive method to detect coronary artery disease(CAD).Most previous studies used traditional logistic regression(LGR)to evaluate the risks for abnormal CAD.Rapidly developing machine learning(Mach-L)techniques could potentially outperform LGR in capturing non-linear relationships.AIM To aims were:(1)Compare the accuracy of Mach-L methods and LGR;and(2)Found the most important factors for abnormal TMPS.METHODS 556 T2D were enrolled in the study(287 men and 269 women).Demographic and biochemistry data were used as independent variables and the sum of stressed score derived from MPS scan was the dependent variable.Subjects with a MPS score≥9 were defined as abnormal.In addition to traditional LGR,classification and regression tree(CART),random forest,Naïve Bayes,and eXtreme gradient boosting were also applied.Sensitivity,specificity,accuracy and area under the receiver operation curve were used to evaluate the respective accuracy of LGR and Mach-L methods.RESULTS Except for CART,the other Mach-L methods outperformed LGR,with gender,body mass index,age,low-density lipoprotein cholesterol,glycated hemoglobin and smoking emerging as the most important factors to predict abnormal MPS.CONCLUSION Four Mach-L methods are found to outperform LGR in predicting abnormal TMPS in Chinese T2D,with the most important risk factors being gender,body mass index,age,low-density lipoprotein cholesterol,glycated hemoglobin and smoking.

Acute coronary syndrome on non-electrocardiogram-gated contrastenhanced computed tomography

It is not rare for acute coronary syndrome(ACS)patients to present with symptoms that are atypical,rather than chest pain.It is sometimes difficult to achieve a definitive diagnosis of ACS for such patients who present with atypical symptoms,normal initial biomarkers of myocardial necrosis,and normal or nondiagnostic electrocardiograms(ECGs).Although cardiac CT allows for assessments of coronary artery stenosis as well as myocardial perfusion defect in patients with suspected ACS,it requires ECG gating and is usually performed with high-performance multislice CT for highly probable ACS patients.However,several recent reports have stated that ACS is detectable by myocardial perfusion defects even on routine non-ECG-gated contrast-enhanced CT.A growing number of contrast-enhanced CT scans are now being performed in emergency departments in search of pathologies responsible for a patient’s presenting symptoms.In order to avoid inappropriate management for this life-threatening event,clinicians should be aware that myocardial perfusion defect is more commonly detectable even on routine non-ECG-gated contrast-enhanced CT performed in search of other pathologies.

Comparison of ^(99m)Tc-methoxyisobutylisonitrile myocardial single-photon emission computed tomography and electron beam computed tomography for detecting coronary artery disease in patients with no myocardial infarction

Background Previous studies have compared single-photon emission computed tomography (SPECT) and electron beam computed tomography (EBCT) in detection of coronary artery disease (CAD) in patients with myocardial infarction (MI) The purpose of this study was to compare SPECT with EBCT in detection of CAD in patients with no MI Methods One hundred and forty-seven patients with suspected CAD underwent stress-rest 99m Tc-methoxyisobutylisonitrile ( 99m Tc-MIBI) myocardial SPECT, cardiac EBCT and coronary angiography (CAG) within one month Of them, 73 patients (aged 52 6±10 6 years old) with no history of MI were included in this study Coronary artery calcium (CAC) was defined as a CT value ≥130 HU within the boundary of coronary artery on EBCT Results There were 35 and 38 patients with or without CAD according to CAG Ninety-six percent of the patients with abnormal SPECT and CAC had a coronary arteries stenosis ≥50%, and 90 9% patients with normal SPECT and EBCT showed no CAD The sensitivity of SPECT and EBCT in detection of CAD was comparable, and the specificity of SPECT (92 1%) was significantly higher than that of EBCT (55 3%) ( P <0 005) For the detection of individual coronary artery stenosis, both sensitivity and specificity of SPECT (75 0% and 93 7%) were significantly higher than those of EBCT (53 3% and 76 7%) ( P <0 025 and P <0 005, respectively) In patients without chest pain, the sensitivity and specificity of SPECT (76 9% and 91 4%) were significantly higher than those of EBCT (23 1% and 69 0%) in detection of a coronary artery stenosis of ≥50% ( P <0 01 and P <0 005, respectively) However, in patients with chest pain, both sensitivity and specificity of SPECT were comparable to those of EBCT In patients ≤45 years old, the sensitivity of SPECT (77 8%) was significantly higher than that of EBCT (27 8%) in assessing a coronary artery stenosis of ≥50% ( P <0 005), and the specificity of SPECT was comparable to that of EBCT In patients >45 years old, the specificity of SPECT (94 3%) was significantly higher than that of EBCT (70 5%) ( P <0 005), and the sensitivity of SPECT was comparable to that of EBCT Conclusion 99m Tc-MIBI myocardial perfusion SPECT has higher accuracy than that of EBCT in detection of CAD in patients without MI

Calculation of Coronary Angiographic Total Blush in Patients with Coronary Artery Disease and its Prognostic Implication

Background： Myocardial perfusion grade （MPG） is an accepted method of evaluating myocardial perfilsion. However, it does not take into the account, the extent of the perfusion. We hypothesized that myocardial blush area times MPG （total blush） would be more accurate than simple MPG, and yield better prognostic information. Methods： About 34 patients were recruited alter they had consented to both coronary angiography （CAG） and single photon emission computed tomography （SPECT）, and divided into two groups. A special dedicated computer was employed to calculate the total blush. The CAG was performed as a conventional way. Scintigraphic technetium 99m methoxyisobutyl-isonitrile rest and stress images were evaluated quantitatively. The comparison was made between stenosis versus chronic total occlusion （CTO）, MPG 1, 2 versus MPG 3, percutaneous intervention （PC1） successful versus failure. A correlation was made between ejection traction （EF） and myocardial perfusion by MPG, total blush, SPECT, and syntax score. Results： The perfusion indices of total blush, summed difference score （SDS） and syntax score were insignificant between the two groups （P 〉 0.05）. However, the left ventricular end diastolic volume was significantly larger in CTO （P 〈 0.05）. The patients with stenosis had better MPG than with CTO （P 〈 0.05）. The increased MPG was associated with increased total blush, higher syntax score, and EF （P 〈 0.05）. Successful PCI resulted in better perfusion indicated by increased total blush, and MPG （P 〈 0.05） but successful PC1 did not change syntax score. EF and SDS significantly. Multivariate linear analysis with EF as the dependent factor and syntax score, SDS, total blush, blush area, and MPG as the independent factors showed a significantly higher degree of correlation （R = 0.87, P 〈 0.05）. Conclusion： Alter PCI the total blush and EF improved significantly indicating its potential application in the thture.