Myocardial Perfusion Scintigraphy Research Articles

The use of myocardial perfusion scintigraphy to screen for asymptomatic coronary artery disease prior to kidney transplantation

Abstract Background and Objectives Advanced chronic kidney disease (CKD) is associated with an increased risk of cardiovascular disease (CVD), including significant asymptomatic coronary artery disease (CAD) [1], compared to the general general public. Additionally, CVD is the leading cause of mortality in kidney transplant recipients [2]. Given the relative scarcity of available organs, individuals are commonly screened for CAD with non-invasive cardiac testing such as Myocardial Perfusion Scintigraphy (MPS). However, the benefits of screening for asymptomatic CAD are unproven and in the absence of an established screening protocol, investigations vary centre to centre and can result in uncertain interpretation of results and unnecessary delays in transplantation. The objective of this study was to assess the benefits of asymptomatic CVD screening of potential kidney transplant recipients, and its impact on transplantation outcomes. Methods This retrospective analysis included all MPS requested by the transplant team during patients’ assessment process between 2015 and 2023. Any resultant coronary angiograms (CA) were reviewed for evidence of significant CAD. Transplant decisions were reviewed to assess the impact of CVD screening on individuals’ transplant status. Results 689 individuals underwent MPS. Of these, 90% required no further cardiovascular investigations. 6% (42 individuals) had subsequent CA. <1% (5) required percutaneous intervention (PCI) whilst the rest (37) were deemed to have no significant CAD. A further 4% (29) required coronary angiography at a later date (>2 years after their MPS), with similar rates of PCI (1%). All three outcome groups (negative MPS, CA referral, CA in the future) had similar rates of diabetes (40%) and previous diagnoses of CAD (14%). The average wait for CA was 283 days post-MPS. Transplant decisions took a further 286 days after CA, which in combination with the delays associated with CA resulted in average delays of 1.5 years. Conclusions The use of MPS to screen for significant asymptomatic CAD identifies only a small proportion of individuals requiring intervention prior to kidney transplantation and significantly delays transplant decisions. These results suggest transplant centres should review their use of CVD screening prior to listing.

The role of stress echocardiography in patients with congenital abnormalities of coronary arteries: two tertiary cardiac centres experience

Abstract Background Coronary anomalies (CA) include anomalous aortic origin of a coronary artery (AAOCA), anomalous coronary artery from the pulmonary artery and coronary fistulae. While outcome of natural history of anomalous left coronary artery from the pulmonary artery (ALCAPA) is poor, assessment of stress-induced ischaemia and/or arrhythmia are warranted for clinical decision making in AAOCA. Purpose The aim of this study was to establish the prevalence of ischaemia during exercise stress echocardiography (ESE) in patients with different congenital CA. Methods Patients with CA who had stress exercise echocardiography from two large tertiary cardiac centres were retrospectively recruited. Treadmill/bike exercise stress echo tests were performed and analysed according to ESC guidelines. Computed tomography (CT), magnetic resonance imaging (MRI), myocardial perfusion scintigraphy, positron emission tomography (PET) and invasive angiogram with intravascular ultrasound (IVUS) were used for CA morphology and myocardial perfusion assessment. Patients with sclerotic stenosis of >50% in any of the coronary arteries were excluded from this study. Results Total 59 patients, including 8 ALCAPA, 4 coronary fistula and 47 AAOCA (12 anomalous aortic origin of the left coronary artery (AAOLCA) and 35 anomalous aortic origin of the right coronary artery (AAORCA)) formed the study cohort. The mean age was 44±17 years. Cardiac symptoms at rest were present in 5 (63%) ALCAPA, 31 (66%) patients with with AAOCA, and none in patients with coronary fistula. Nine patients (7 ALCAPA, 1 coronary fistula and 1 AAOLCA) had undergone previous repair. Out of 47 patients with AAOCA patients, 31 (66%) had interarterial course of coronary arteries, and 8 (17%) had intramural course. A positive ESE presents in 2 (25%) ALCAPA, 1 (25%) coronary fistula patient and 1 (2%) AAOCA patient. Myocardial perfusion was assessed in 12 of 59 (20%) patients, of which 9 were AAOCA. Myocardial perfusion studies were negative in 11 patients with negative ESE tests, while only in one patient with AAOLCA myocardial perfusion defects were found on MRI and PET despite negative ESE. No major adverse cardiovascular events were observed during follow-up of patients with negative ESE. Following ESE, surgical repair of CA has been performed in 3 patients with AAORCA and in 2 patients with AAOLCA based on either symptoms attributable to anomalous coronary, evidence of myocardial ischaemia on myocardial perfusion assessment or high-risk anatomy.While 4 out of 5 repaired patients were symptomatic before repair, they became asymptomatic following repair. Conclusions Incidence of ischaemia on exercise stress echo is extremely low in AAOCA patients despite symptoms at rest and malignant anatomical features. Improving stress echo methodology by using myocardial perfusion assessment might shed a light on this discrepancy between ESE results and symptomatic status/high-risk anatomy.

ECHO-MPS, a dual modality strategy of cardiac imaging to identify myocardial ischemia.

We aimed to evaluate an approach with resting echocardiography (TTE) and stress myocardial perfusion scintigraphy (MPS) compared to standard MPS in patients with stable angina and normal left ventricle (LV). We hypothesized that normal LV on TTE may allow for the elimination of rest MPS without compromising accuracy and offering an efficient diagnostic pathway with reduced radiation exposure. In a prospective, non-randomized study TTE was performed prior to MPS in patients (pts) referred for assessment of coronary artery disease (CAD). In pts with normal LV assessment was performed using the hybrid and the standard approach. TTE and MPS were interpreted by two TTE readers (ER1-2) and two MPS readers (NR1-2). ECHO-MPS was compared with standard MPS for diagnostic accuracy. 103 patients, mean age 61 ± 12 year, (63M, 40W) were recruited. Standard MPS were normal in 75 patients and abnormal in 28 patients, with the hybrid approach 79 studies were reported as normal and 24 studies as abnormal. Kappa values were 0.580, (p < 0.001) for large, 0.394, (p < 0.001) for medium, and 0.298 (p = 0.002) for small defects. With standard MPS as a reference, sensitivity for detection of perfusion defects by ECHO-MPS was 75% (95% CI 0.67-0.83) [NR2] and 78% (95% CI 0.70-0.86)[NR1]. Specificity was 95% (95% CI 0.90-0.99) [NR2] and 95% (CI 95%CI 0.90-0.99) [NR1]. ECHO-MPS protocol provides similar diagnostic accuracy as standard stress-rest MPS. In patients with normal systolic LV function in TTE, performing only stress MPS provides similar information as standard rest and stress MPS.

Myocardial Ischemia after Severe Scorpion Envenomation: A Narrative Review.

Myocardial ischemia after severe scorpion envenomation is rarely reported. The aim of this review was to elaborate on a review of myocardial ischemia after severe scorpion envenomation and to detail the mechanism of this myocardial hypoperfusion. We used the PubMed database and entered the following keywords in MeSH research: scorpion envenomation, myocardial ischemia, myocardial perfusion scintigraphy, echocardiography, and troponins. The literature analysis confirmed that severe scorpion envenomation can be complicated by temporary myocardial ischemia, based on electrocardiographic, histopathologic, echocardiographic, myocardial perfusion scintigraphy, and biological studies. The correlation between clinical manifestations, laboratory and electrocardiographic evidence of myocardial damage, echocardiographic studies, perfusion scintigraphy abnormalities, and histopathologic findings are suggestive of lesions of cardiac fibers secondary to myocardial ischemia. Myocardial hypoperfusion may be due to multiple factors. First, catecholamine storms can induce microvascular constriction. On the other hand, the release of catecholamines through a complex neurohormonal interaction with other neuropeptides and cytokine release can produce/induce major coronary microvascular constriction and/or microvascular injury, leading to microvascular acute coronary syndrome with Takotsubo cardiomyopathy. The management of severe scorpion envenomation with severe myocardial failure and pulmonary edema is based on oxygen with invasive or noninvasive ventilator support. Dobutamine improves cardiac function after scorpion envenomation. Antiplatelet therapy is not recommended. In conclusion, severe scorpion envenomation can be complicated by temporary myocardial ischemia, which can be due to multiple factors.

Myocardial Perfusion Scintigraphy in Diagnosic of Coronary Heart Disease

&amp;lt;i&amp;gt;Introduction: &amp;lt;/i&amp;gt;Atherosclerosis plays a key role in the etiopathogenesis of cardiovascular diseases. Atherosclerosis is a generalized chronic inflammatory disease of the vascular wall, which results in anatomical and histological changes that, together with functional changes, lead to endothelial dysfunction, narrowing of the arterial lumen, and insufficient blood supply to the tissues. The shift in the incidence of cardiovascular diseases to younger age groups is alarming. The presence of microvascular changes in the myocardium is significant. The high incidence of cardiovascular diseases, especially ischemic heart disease, requires early diagnosis and modern treatment. &amp;lt;i&amp;gt;Aim: &amp;lt;/i&amp;gt;The aim of the paper is to analyse and point out early diagnosis of coronary heart disease using nuclear medicine methods. &amp;lt;i&amp;gt;Set of examined patients and methodology: &amp;lt;/i&amp;gt;Using nuclear medicine methods, we try to detect these changes in time and thus prevent the occurrence of acute coronary events. In nuclear cardiology, instead of a large-area scintillation detector, a new type of cardio-gamma camera &amp;quot;Discovery CZT 530c&amp;quot; based on the principle of semiconductor detectors began to be used. The abbreviation CZT stands for semiconductor composition (Cadmium-Zinc-Tellur). The set of respondents consisted of 4270 people examined in the years 2014-2016 by myocardial perfusion scintigraphy. There were 950 diabetic patients in the analysed group of the 4270 examined. &amp;lt;i&amp;gt;Results:&amp;lt;/i&amp;gt; In the analysed group of 4270 respondents, 61% had negative findings and 39% had positive findings in terms of the presence of ischemic heart disease. In the group of diabetic patients, there was a negative finding in 28% of respondents and a positive finding in 72% of the respondents in the sense of positive ischemic heart disease. Using myocardial perfusion scintigraphy in the diagnosis of functional changes, we confirmed a great benefit in detecting early changes in coronary heart disease, including in the diagnosis of microvascular angina. &amp;lt;i&amp;gt;Conclusion:&amp;lt;/i&amp;gt; Nuclear medicine methods are of great benefit for the diagnosis of small vessel disease, diabetic cardiomyopathy and cardiac autonomic neuropathy in patients with diabetes mellitus. The new type of cardio gamma camera &amp;quot;Discovery CZT 530c&amp;quot; allows more accurate assessment of myocardial perfusion abnormalities and at the same time the reduction of the radiopharmaceutical dose reduces the patient&amp;apos;s radiation load by 50%.

Basal and post-stress ceramide-based risk score CERT1 predicts all-cause mortality and nonfatal myocardial infarction in patients with suspected or established coronary artery disease undergoing stress myocardial perfusion scintigraphy

Background and aimWe examined whether a plasma ceramide-based risk score (CERT1 score), a newly proposed tool for cardiovascular risk prediction, is associated with an increased risk of all-cause mortality and nonfatal myocardial infarction in patients with suspected or known coronary artery disease (CAD). Methods and resultsWe studied 167 ambulatory patients who consecutively underwent stress myocardial perfusion scintigraphy (MPS) for clinical reasons in 2017 (at baseline) and then followed for a median of 6 years (inter-quartile range: 4.7–6.6 years). For the calculation of the CERT1 score, both before and after stress MPS, we measured three specific plasma ceramide concentrations [Cer(d18:1/16:0), Cer(d18:1/18:0) and Cer(d18:1/24:1)] and their ratio to Cer(d18:1/24:0) using a targeted liquid chromatography-tandem mass spectrometry assay. The primary outcome of the study was a composite of all-cause mortality or nonfatal myocardial infarction. During a median of 6 years, a total of 50 events occurred (26 all-cause deaths and 24 nonfatal myocardial infarctions). There was a significant association between pre-stress CERT1 risk categories (high vs. low risk) at baseline and the risk of developing the primary composite outcome (unadjusted HR 1.78, 95% CI 1.02–3.14). This risk remained significant after adjustment for age, sex, smoking, diabetes, pre-existing CAD, left ventricular ejection fraction, and stress-induced inducible myocardial ischemia on MPS (adjusted HR 2.28, 95% CI 1.17–4.41, p = 0.015). Almost identical results were observed for post-stress CERT1 risk categories. ConclusionsPre-stress and post-stress CERT1 high-risk categories at baseline were strongly associated with an increased long-term risk of all-cause mortality or nonfatal myocardial infarction in patients with suspected or established CAD.

Subdiaphragmatic activity-related artifacts in myocardial perfusion scintigraphy.

Myocardial perfusion imaging (MPI) with single photon emission computed tomography is an established non-invasive technique for assessing myocardial ischemia. This method involves the intravenous administration of a radiopharmaceutical that accumulates in the heart muscle proportional to regional blood flow. However, image quality and diagnostic accuracy can be compromised by various technical and patient-related factors, including high non-specific radiopharmaceutical uptake in abdominal organs such as the stomach, intestines, liver, and gall-bladder, leading to subdiaphragmatic artifacts. These artifacts are particularly problematic for evaluating inferior wall perfusion and often necessitate repeated imaging, which decreases gamma camera availability and prolongs imaging times. Despite numerous investigated techniques to reduce interfering gastrointestinal activity, results have been inconsistent, and current MPI guidelines provide scant information on effective procedures to mitigate this issue. Based on our experience, some possible approaches to reducing artifacts include choosing stress testing with an exercise stress test, when possible, late imaging, fluid intake, and consuming carbonated water immediately before imaging.

P.226: Coronary artery disease assessment using Tc-99m MIBI gated myocardial perfusion scintigraphy prior to kidney transplantation.

P.226: Coronary artery disease assessment using Tc-99m MIBI gated myocardial perfusion scintigraphy prior to kidney transplantation.

The Value of Naples Prognostic Score in Predicting Ischemia on Myocardial Perfusion Scintigraphy

Objectives: Naples prognostic score (NPS) is a recently established score that measures inflammation and nutritional conditions. This score includes lymphocyte-to-monocyte ratio, neutrophil-to-lymphocyte ratio, total cholesterol levels, and serum albumin levels. Initial studies have shown that the NPS score has more prognostic value than other inflammatory parameters in some cancer diseases. Recently, the association of the NPS score with various cardiovascular diseases has started to be evaluated. The association between ischemia in myocardial perfusion scanning and the Naples score has not yet been investigated. In this study, we evaluated if the NPS may help predict ischemia in myocardial perfusion scanning. Methods: This study included a total of 110 patients. All patients underwent myocardial perfusion scintigraphy (MPS) at the nuclear medicine department, with dipyridamole or adenosine administered as the pharmaceutical stressor. The subjects were divided into two groups according to the presence or absence of ischemia on gated single-photon emission computed tomography (SPECT) MPI. Laboratory values within the past month before MPS were obtained from digital records for both groups. The NPS was calculated for each group. Laboratory values and NPSs of the groups were compared. Results: All individuals in the trial had gated SPECT MPI. The average age of individuals was 59.8±11.1 years, with 62 patients (56%) being male. Subjects were divided into two groups according to the presence or absence of ischemia on gated SPECT MPI. Table 1 displays the demographics of the whole study population. Based on the laboratory data (Table 2), there was no significant difference in the demographic features of the groups. The ischemia group had significantly higher levels of white blood cell count (cells/ μL), neutrophil count (cells/µL), hemoglobin (g/dL), CRP (mg/L), and NPS (8.6±2.2, 7.7±1.9, p=0.040; 5.0±2.1, 4.1±1.3, p=0.014; 12.6±1.7, 13.4±1.8, p=0.025; 8.2±2.0, 7.9±2.0, p=0.004; 2.6±1.0, 1.5). Other laboratory results did not differ across the groups. Conclusion: Our findings indicated an association between NPS and the detection of ischemia in MPS. NPS is an independent variable for diagnosing myocardial ischemia in stable coronary artery disease patients.

Diagnostic Performance of Deep Learning Model Using Quantitative Data for Detection of Multivessel Coronary Artery Disease in Stress Myocardial Perfusion Scintigraphy

Diagnostic Performance of Deep Learning Model Using Quantitative Data for Detection of Multivessel Coronary Artery Disease in Stress Myocardial Perfusion Scintigraphy

A review of prognostic prediction of coronary artery disease patients with myocardial perfusion scintigraphy and artificial intelligence

A review of prognostic prediction of coronary artery disease patients with myocardial perfusion scintigraphy and artificial intelligence

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.

Relationship between left ventricular mechanical dyssynchrony and accelerated 99mTc-MIBI clearance in patients with heart failure

Aim. To evaluate 99mTc-methoxy-isobutyl-isonitrile (99mTc-MIBI) washout rate and its relationship with contractility and left ventricular (LV) mechanical dyssynchrony in patients with heart failure (HF) of non-ischemic origin.Material and methods. The study included 20 patients with HF of non-ischemic origin with indications for cardiac resynchronization therapy (CRT). Ten patients without HF were included in the comparison group. All patients underwent 99mTc-MIBI myocardial perfusion scintigraphy (MPS). We assessed the 99mTc-MIBI washout rate, as well as LV perfusion, contractility, and mechanical dyssynchrony using phase analysis data (phase standard deviation, histogram bandwidth (HBW), asymmetry, and gradient). Six months after CRT, all patients with HF underwent MPS to assess the changes of studied parameters.Results. According to MPS, patients with HF had a higher 99mTc-MIBI washout rate from the LV myocardium compared with the comparison group (10,9 (8,49-13,8) vs 3,98 (0,9-9,8)%, p=0,0001), as well as severe LV mechanical dyssynchrony (standard deviation: 66 (55,11-73,24) vs 13,1 (10,1-19,6), p&lt;0,0001; HBW: 207 (165-246) vs 40 (33-66), p&lt;0,0001). The 99mTc-MIBI washout rate was positively correlated with LV end-diastolic (r=0,46, p&lt;0,001) and LV end-systolic volumes (r=0,44, p&lt;0,001) and negatively correlated with LV ejection fraction (r=0,41, p&lt;0,001). A moderate correlation was found between the 99mTc-MIBI washout rate and following LV mechanical dyssynchrony and contractility parameters: HBW (r=0,412, p&lt;0,001), asymmetry (r=-0,41, p&lt;0,001), gradient (r=-0,44, p&lt;0,001), wall motion (r=-0,45, p=0,001), wall thickening (r=-0,54, p&lt;0,001). Six months after CRT, all patients showed a significant decrease in the 99mTc-MIBI washout rate from 12,4 (10,3-14,9) to 8,14 (3,37-8,88)%, p=0,0006.Conclusion. In patients with HF of non-ischemic origin, an increase in the 99mTc-MIBI washout rate from the LV myocardium is associated with the severity of impaired cardiac contractility and mechanical dyssynchrony.

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.