Impact on cardiovascular outcome of coronary revascularization-induced changes in ischemic perfusion defect and myocardial flow reserve.

PURPOSE: We evaluated the impact on cardiovascular outcome of coronary revascularization-induced changes in ischemic total perfusion defect (ITPD) and myocardial flow reserve (MFR) as assessed by 82Rb positron emission tomography (PET)/computed tomography (CT) imaging. METHODS: The study included 102 patients referred to 82Rb PET/CT myocardial perfusion imaging before and after coronary revascularization. All patients were followed for the occurrence of cardiovascular events (cardiac death, nonfatal myocardial infarction, repeated revascularization, and heart failure) after the second imaging study. RESULTS: During a median follow-up of 20 months, 21 events occurred. The clinical characteristics were comparable between patients with and without events. In the overall study population, after revascularization, there was a significant reduction (P < 0.001) of ITPD, while hyperemic myocardial blood flow (MBF) (P < 0.01) and MFR (P < 0.05) significantly improved. Event rate was higher in patients with ITPD (P < 0.005) or MFR (P < 0.001) worsening compared to those with unchanged or improved ITPD or MFR. At Cox univariable analysis, ITPD and MFR worsening resulted in predictors of events (both P < 0.05). Patients with worsening of both ITPD and MFR had the worst event-free survival (log-rank 32.9, P for trend < 0.001). CONCLUSIONS: In patients with stable CAD, worsening of ITPD and MFR after revascularization procedures is associated with higher risk of cardiovascular events. Follow-up MPI with 82Rb PET/CT may improve risk stratification in patients submitted to coronary revascularization.

Prediction of placenta accreta spectrum in patients with placenta previa using a clinical, US and MRI combined model: A retrospective study with external validation.

PURPOSE: To build and validate a predictive model of placental accreta spectrum (PAS) in patients with placenta previa (PP) combining clinical risk factors (CRF) with US and MRI signs. METHOD: Our retrospective study included patients with PP from two institutions. All patients underwent US and MRI examinations for suspicion of PAS. CRF consisting of maternal age, cesarean section number, smoking and hypertension were retrieved. US and MRI signs suggestive of PAS were evaluated. Logistic regression analysis was performed to identify CRF and/or US and MRI signs associated with PAS considering histology as the reference standard. A nomogram was created using significant CRF and imaging signs at multivariate analysis, and its diagnostic accuracy was measured using the area under the binomial ROC curve (AUC), and the cut-off point was determined by Youden's J statistic. RESULTS: A total of 171 patients were enrolled from two institutions. Independent predictors of PAS included in the nomogram were: 1) smoking and number of previous CS among CRF; 2) loss of the retroplacental clear space at US; 3) intraplacental dark bands, focal interruption of the myometrial border and placental bulging at MRI. A PAS-prediction nomogram was built including these parameters and an optimal cut-off of 14.5 points was identified, showing the highest sensitivity (91%) and specificity (88%) with an AUC value of 0.95 (AUC of 0.80 in the external validation cohort). CONCLUSION: A nomogram-based model combining CRF with US and MRI signs might help to predict PAS in PP patients, with MRI contributing more than US as imaging evaluation.

Age-Specific Cardiovascular Risk Factors for Major Adverse Cardiac Events in Patients Undergoing Myocardial Perfusion Imaging.

BACKGROUND: The prevalence of traditional cardiovascular risk factors shows different age-specific patterns. It is not known whether the prognostic impact of risk factors is similarly age-specific. We evaluated the profiles of cardiovascular risk factors and their prognostic impact on coronary artery disease (CAD) in relation to age. METHODS: We included 3667 patients with suspected or known CAD undergoing stress myocardial perfusion imaging (MPI). We evaluated the risk for major adverse cardiac events (MACE) within three years from the index MPI in patients belonging to three groups according to age tertile distribution: <59, 59-68, and >68 years. Gender, body mass index, diabetes, hypertension, dyslipidemia, family history of CAD, smoking, angina, dyspnea, previous CAD, and MPI outcome were assessed as risk factors by a multivariable Cox's regression. RESULTS: The three-year risk of MACE increased progressively with age and was 9%, 13%, and 18% for each group, respectively (p < 0.0001). Dyspnea and abnormal MPI outcome were significant risk factors for all age groups. Diabetes and smoking were significant from the age of 59 onwards, while hypertension resulted significant for patients older than 68 years. CONCLUSIONS: The number of risk factors was significantly associated with the occurrence of MACE increase with age. It is noteworthy that a personal history of CAD was not useful for risk stratification, while MPI results were.

Prognostic value of myocardial perfusion imaging by cadmium zinc telluride single-photon emission computed tomography in patients with suspected or known coronary artery disease: a systematic review and meta-analysis.

BACKGROUND: Aim of this study was to define the prognostic value of stress myocardial perfusion imaging by cadmium zinc telluride (CZT) single-photon emission computed tomography (SPECT) for prediction of adverse cardiovascular events in patients with known or suspected coronary artery disease (CAD). METHODS AND RESULTS: Studies published until November 2022 were identified by database search. We included studies using stress myocardial perfusion imaging by CZT-SPECT to evaluate subjects with known or suspected CAD and providing primary data of adverse cardiovascular events. Total of 12 studies were finally included recruiting 36,415 patients. Pooled hazard ratio (HR) for the occurrence of adverse events was 2.17 (95% confidence interval, CI, 1.78-2.65) and heterogeneity was 66.1% (P = 0.001). Five studies reported data on adjusted HR for the occurrence of adverse events. Pooled HR was 1.69 (95% CI, 1.44-1.98) and heterogeneity was 44.9% (P = 0.123). Seven studies reported data on unadjusted HR for the occurrence of adverse events. Pooled HR was 2.72 (95% CI, 2.00-3.70). Nine studies reported data useful to calculate separately the incidence rate of adverse events in patients with abnormal and normal myocardial perfusion. Pooled incidence rate ratio was 2.38 (95% CI, 1.39-4.06) and heterogeneity was 84.6% (P < 0.001). The funnel plot showed no evidence of asymmetry (P = 0.517). At meta-regression analysis, we found an association between HR for adverse events and presence of angina symptoms and family history of CAD. CONCLUSIONS: Stress myocardial perfusion imaging by CZT-SPECT is a valuable noninvasive prognostic indicator for adverse cardiovascular events in patients with known or suspected CAD.

Combined evaluation of CAC score and myocardial perfusion imaging in patients at risk of cardiovascular disease: where are we and what do the data say.

Advances in the prevention and treatment of cardiovascular disease (CVD) over the last decades have led to a marked reduction in mortality for CVD. Nevertheless, atherosclerosis leading to coronary artery disease and stroke remains one of the most common causes of death in the world. The usefulness of imaging tests in the early identification of disease led to identify subjects at major risk of poor outcomes, suggesting risk factor modification. The aim of this article is to analyze the state of art of combined imaging in patients at risk of CVD referred to MPI evaluation, to highlight the present and potential features able to provide incremental prognostic information to help clinicians in patient management and to reduce adverse events.

Tracers for Cardiac Imaging: Targeting the Future of Viable Myocardium.

Ischemic heart disease is the leading cause of mortality worldwide. In this context, myocardial viability is defined as the amount of myocardium that, despite contractile dysfunction, maintains metabolic and electrical function, having the potential for functional enhancement upon revascularization. Recent advances have improved methods to detect myocardial viability. The current paper summarizes the pathophysiological basis of the current methods used to detect myocardial viability in light of the advancements in the development of new radiotracers for cardiac imaging.

Prevalence of cancer therapy cardiotoxicity as assessed by imaging procedures: A scoping review.

BACKGROUND: Advances in treatment and optimization of chemotherapy protocols have greatly improved survival in cancer patients. Unfortunately, treatment can cause a reduction in left ventricular (LV) ejection fraction (EF) leading to cancer therapy-related cardiac dysfunction (CTRCD). We conducted a scoping review of published literature in order to identify and summarize the reported prevalence of cardiotoxicity evaluated by noninvasive imaging procedures in a wide-ranging of patients referred to cancer treatment as chemotherapy and/or radiation therapy. METHODS: Different databases were checked (PubMed, Embase, and Web of Science) to identify studies published from January 2000 to June 2021. Articles were included if they reported data on LVEF evaluation in oncological patients treated with chemotherapeutic agents and/or radiotherapy, measured by echocardiography and/or nuclear or cardiac magnetic resonance imaging test, providing criteria of CTRCD evaluation such as the specific threshold for LVEF decrease. RESULTS: From 963 citations identified, 46 articles, comprising 6841 patients, met the criteria for the inclusion in the scoping review. The summary prevalence of CTRCD as assessed by imaging procedures in the studies reviewed was 17% (95% confidence interval, 14-20). CONCLUSIONS: The results of our scoping review endorse the recommendations regarding imaging modalities to ensure identification of cardiotoxicity in patients undergoing cancer therapies. However, to improve patient management, more homogeneous CTRCD evaluation studies are required, reporting a detailed clinical assessment of the patient before, during and after treatment.

External validation and update of the J-ACCESS model in an Italian cohort of patients undergoing stress myocardial perfusion imaging.

BACKGROUND: Cardiovascular risk models are based on traditional risk factors and investigations such as imaging tests. External validation is important to determine reproducibility and generalizability of a prediction model. We performed an external validation of t the Japanese Assessment of Cardiac Events and Survival Study by Quantitative Gated SPECT (J-ACCESS) model, developed from a cohort of patients undergoing stress myocardial perfusion imaging. METHODS: We included 3623 patients with suspected or known coronary artery disease undergoing stress single-photon emission computer tomography (SPECT) myocardial perfusion imaging at our academic center between January 2001 and December 2019. RESULTS: In our study population, the J-ACCESS model underestimated the risk of major adverse cardiac events (cardiac death, nonfatal myocardial infarction, and severe heart failure requiring hospitalization) within three-year follow-up. The recalibrations and updated of the model slightly improved the initial performance: C-statistics increased from 0.664 to 0.666 and Brier score decreased from 0.075 to 0.073. Hosmer-Lemeshow test indicated a logistic regression fit only for the calibration slope (P = .45) and updated model (P = .22). In the update model, the intercept, diabetes, and severity of myocardial perfusion defects categorized coefficients were comparable with J-ACCESS. CONCLUSION: The external validation of the J-ACCESS model as well as recalibration models have a limited value for predicting of three-year major adverse cardiac events in our patients. The performance in predicting risk of the updated model resulted superimposable to the calibration slope model.

Prediction of outcome by 82Rb PET/CT in patients with ischemia and nonobstructive coronary arteries.

BACKGROUND: The purpose of this study was to assess the prognostic value of cardiac 82Rb positron emission tomography (PET)/computed tomography (CT) imaging in patients with myocardial ischemia of nonobstructive coronary arteries (INOCA). METHODS: We retrospectively evaluated 311 INOCA patients who underwent rest stress 82Rb PET/CT. Cardiac end points were cardiac death, myocardial infarction, or late coronary revascularization. A parametric survival model was also used to identify how the variables influenced time to event. RESULTS: During a median follow-up of 37 months (range 6-108), 23 (7%) cardiac events occurred. In patients with events total perfusion defect (TPD) was higher and myocardial flow reserve (MFR) lower compared to those without events (both P < .001). At multivariable Cox analysis, increased TPD (i.e., ≥ 5%) and reduced MFR (i.e., < 2) were predictors of events (both P < .001). At Weibull survival analysis, the highest probability of cardiac events and risk acceleration were observed in patients with both increased TPD and reduced MFR. Annualized event rate was higher in patients with reduced MFR compared to those with preserved MFR (P < .001). CONCLUSION: In patients with INOCA, the combined evaluation of myocardial perfusion and coronary vascular function by 82Rb PET/CT is able to identify those at higher risk of cardiac events.

Regional myocardial perfusion imaging in predicting vessel-related outcome: interplay between the perfusion results and angiographic findings.

BACKGROUND: Despite myocardial perfusion imaging (MPI) by cadmium-zinc-telluride (CZT) single-photon emission computed tomography (SPECT) camera is largely used in the diagnosis and risk stratification of patients with suspected or known coronary artery disease (CAD), no data are available on the prognostic value of a regional MPI evaluation. We evaluated the prognostic value of regional MPI by the CZT camera in predicting clinical outcomes at the vessel level in patients with available angiographic data. METHODS AND RESULTS: Five hundred and forty-one subjects with suspected or known CAD referred to 99mTc-sestamibi gated CZT-SPECT cardiac imaging and with available angiographic data were studied. Both regional total perfusion deficit (TPD) and ischemic TPD (ITPD) were calculated separately for each vascular territory (left anterior descending, left circumflex, and right coronary artery). The outcome end points were cardiac death, target vessel-related myocardial infarction, or late coronary revascularization. The prevalence of CAD ≥ 50%, regional stress TPD, and regional ITPD was significantly higher in vessels with events as compared to those without (both P < 0.001). The receiver operating characteristics area under the curve for regional ITPD for the identification of vessel-related events was 0.81 (95% confidence interval 0.75-0.86). An ITPD value of 2.0% provided the best trade-off for identifying the vessel-related event. At multivariable analysis, both CAD ≥ 50% and ITPD ≥ 2.0% resulted in independent predictors of events. CONCLUSIONS: Regional myocardial perfusion assessed by the CZT camera demonstrated good reliability in predicting vessel-related events in patients with suspected or known CAD.

Cardiovascular magnetic resonance native T1 mapping in Anderson-Fabry disease: a systematic review and meta-analysis.

BACKGROUND: T1 mapping is an established cardiovascular magnetic resonance (CMR) technique that can characterize myocardial tissue. We aimed to determine the weighted mean native T1 values of Anderson-Fabry disease (AFD) patients and the standardized mean differences (SMD) as compared to healthy control subjects. METHODS: A comprehensive literature search of the PubMed, Scopus and Web of Science databases was conducted according to the PRISMA statement to retrieve original studies reporting myocardial native T1 values in AFD patients and healthy controls. A random effects model was used to calculate SMD, and meta-regression analysis was conducted to explore heterogeneity sources. Subgroup analysis was also performed according to scanner field strength and sequence type. RESULTS: From a total of 151 items, 14 articles were included in the final analysis accounting for a total population of 982 subjects. Overall, the weighted mean native T1 values was 984 ± 47 ms in AFD patients and 1016 ± 26 ms in controls (P < 0.0001) with a pooled SMD of - 2.38. In AFD patients there was an inverse correlation between native T1 values and male gender (P = 0.002) and left ventricular hypertrophy (LVH) (P < 0.001). Subgroup analyses confirmed lower T1 values in AFD patients compared to controls with a pooled SMD of -  2.54, -  2.28, -  2.46 for studies performed on 1.5T with modified Look-Locker inversion recovery (MOLLI), shortened MOLLI and saturation-recovery single-shot acquisition, respectively and of -  2.41 for studies conducted on 3T. CONCLUSIONS: Our findings confirm a reduction of native T1 values in AFD patients compared to healthy controls and point out that the degree of T1 shortening in AFD is influenced by gender and LVH. Although T1 mapping is useful in proving cardiac involvement in AFD patients, there is need to standardize shreshold values according to imaging equipment and protocols.

Simultaneous assessment of myocardial perfusion and adrenergic innervation in patients with heart failure by low-dose dual-isotope CZT SPECT imaging.

BACKGROUND: In patients with heart failure (HF) sequential imaging studies have demonstrated a relationship between myocardial perfusion and adrenergic innervation. We evaluated the feasibility of a simultaneous low-dose dual-isotope 123I/99mTc-acquisition protocol using a cadmium-zinc-telluride (CZT) single-photon emission computed tomography (SPECT) camera. METHODS AND RESULTS: Thirty-six patients with HF underwent simultaneous low-dose 123I-metaiodobenzylguanidine (MIBG)/99mTc-sestamibi gated CZT-SPECT cardiac imaging. Perfusion and innervation total defect sizes and perfusion/innervation mismatch size (defined by 123I-MIBG defect size minus 99mTc-sestamibi defect size) were expressed as percentages of the total left ventricular (LV) surface area. LV ejection fraction (EF) significantly correlated with perfusion defect size (P < .005), innervation defect size (P < .005), and early (P < .05) and late (P < .01) 123I-MIBG heart-to-mediastinum (H/M) ratio. In addition, late H/M ratio was independently associated with reduced LVEF (P < .05). Although there was a significant relationship (P < .001) between perfusion and innervation defect size, innervation defect size was larger than perfusion defect size (P < .001). At multivariable linear regression analysis, 123I-MIBG washout rate (WR) correlated with perfusion/innervation mismatch (P < .05). CONCLUSIONS: In patients with HF, a simultaneous low-dose dual-isotope 123I/99mTc-acquisition protocol is feasible and could have important clinical implications.

Impact of COVID-19 pandemic on 2-[18F]FDG PET/CT imaging work-flow in a single medical institution: comparison among the three Italian waves.

PURPOSE: To compare the impact of COVID-19 pandemic on 2-[18F]FDG PET/CT imaging work-flow during the three waves in a medical institution of southern of Italy. METHODS: We retrospectively reviewed the numbers and results of 2-[18F]FDG PET/CT studies acquired during the following three periods of the COVID-19 waves: 1) February 3-April 30, 2020; 2) October 15, 2020-January 15, 2021; and 3) January 18-April 16, 2021. RESULTS: A total of 861 PET/CT studies in 725 patients (388 men, mean age 64 ± 4 years) was acquired during the three waves of COVID-19 pandemic. The majority (94%) was performed for diagnosis/staging (n = 300) or follow-up (n = 512) of neoplastic diseases. The remaining 49 studies (6%) were acquired for non-oncological patients. The distribution of number and type of clinical indications for PET/CT studies in the three waves were comparable (p = 0.06). Conversely, the occurrence of patients positive for COVID-19 infection progressively increased (p < 0.0001) from the first to third wave; in particular, patients with COVID-19 had active infection before PET/CT study as confirmed by molecular oro/nasopharyngeal swab. CONCLUSION: Despite the restrictive medical measures for the emergency, the number of 2-[18F]FDG PET/CT studies was unchanged during the three waves guaranteeing the diagnostic performance of PET/CT imaging for oncological patients.

Diagnostic value of clinical risk scores for predicting normal stress myocardial perfusion imaging in subjects without coronary artery calcium.

BACKGROUND: We evaluated if risk scores commonly used to predict the absence of significant stenosis at coronary computed tomography (CT) angiography are useful to predict a normal stress myocardial perfusion imaging (MPI) study. METHODS: Our cohort included a total of 1422 consecutive patients with zero coronary artery calcium score (ZCS) who underwent 82Rb PET/CT for evaluation of suspected coronary artery disease (CAD). Predictive models were constructed as reported by Genders et al. and Alshahrani et al., and the probability of abnormal summed stress score (SSS) and of reduced myocardial perfusion reserve (MPR) based on these risk scores was assessed. RESULTS: In the overall population, the prevalence of abnormal SSS was 0.10 and the prevalence of reduced MPR was 0.17 (both P < .001).The observed frequencies of abnormal SSS and reduced MPR vs the probabilities predicted by the Genders and Alshahrani models were above the diagonal identity line, highlighting an underestimation of the observed occurrence by these models. The areas under the receiver operating characteristic curve of the Genders and Alshahrani models indicated lack of discriminative ability for predicting abnormal SSS (0.547 and 0.527) and reduced MPR (0.509 and 0.538). The Hosmer-Lemeshow test revealed that both models underestimated the observed occurrence of abnormal SSS and reduced MPR. CONCLUSIONS: Available models were unable to identify among patients with ZCS those with a low probability of a normal stress MPI study. Thus, an optimal approach to rule out from MPI patients without detectable coronary calcium still needs to be improved.

A machine learning-based approach to directly compare the diagnostic accuracy of myocardial perfusion imaging by conventional and cadmium-zinc telluride SPECT.

BACKGROUND: We evaluated the performance of conventional (C) single-photon emission computed tomography (SPECT) and cadmium-zinc-telluride (CZT)-SPECT in a large cohort of patients with suspected or known coronary artery disease (CAD) and compared the diagnostic accuracy of the two systems using machine learning (ML) algorithms. METHODS AND RESULTS: A total of 517 consecutive patients underwent stress myocardial perfusion imaging (MPI) by both C-SPECT and CZT-SPECT. In the overall population, an excellent correlation between stress MPI data and left ventricular (LV) functional parameters measured by C-SPECT and by CZT-SPECT was observed (all P < .001). ML analysis performed through the implementation of random forest (RF) and k-nearest neighbors (NN) algorithms proved that CZT-SPECT has greater accuracy than C-SPECT in detecting CAD. For both algorithms, the sensitivity of CZT-SPECT (96% for RF and 60% for k-NN) was greater than that of C-SPECT (88% for RF and 53% for k-NN). CONCLUSIONS: MPI data and LV functional parameters obtained by CZT-SPECT are highly reproducible and provide good correlation with those obtained by C-SPECT. ML approach showed that the accuracy and sensitivity of CZT-SPECT is greater than C-SPECT in detecting CAD.

Machine learning analysis: general features, requirements and cardiovascular applications.

Artificial intelligence represents the science which will probably change the future of medicine by solving actually challenging issues. In this special article, the general features of machine learning are discussed. First, a background explanation regarding the division of artificial intelligence, machine learning and deep learning is given and a focus on the structure of machine learning subgroups is shown. The traditional process of a machine learning analysis is described, starting from the collection of data, across features engineering, modelling and till the validation and deployment phase. Due to the several applications of machine learning performed in literature in the last decades and the lack of some guidelines, the need of a standardization for reporting machine learning analysis results emerged. Some possible standards for reporting machine learning results are identified and discussed deeply; these are related to study population (number of subjects), repeatability of the analysis, validation, results, comparison with current practice. The way to the use of machine learning in clinical practice is open and the hope is that, with emerging technology and advanced digital and computational tools, available from hospitalization and subsequently after discharge, it will also be possible, with the help of increasingly powerful hardware, to build assistance strategies useful in clinical practice.

Effect of changes in perfusion defect size during serial stress myocardial perfusion imaging on cardiovascular outcomes in patients treated with primary percutaneous coronary intervention after myocardial infarction.

BACKGROUND: We evaluated the prognostic value of changes in perfusion defect size (PDS) on serial MPS in patients treated with primary percutaneous coronary intervention (PCI) after acute myocardial infarction (AMI). METHODS: We enrolled 112 patients treated with primary PCI after AMI who underwent two stress MPS within 1 month and after 6 months. Improvement in PDS was defined as a reduction ≥5%. Remodeling was defined as an increase in left ventricular (LV) end-diastolic volume index ≥20%. Cardiac events included cardiac death, nonfatal MI, unstable angina, repeated revascularization, and heart failure. RESULTS: During a median follow-up of 86 months, 22 events occurred. Event rate was higher (P < .01) in patients with worsening of PDS compared to those with unchanged or improved PDS. Moreover, patients with remodeling had a higher (P < .001) event rate compared to those without. At Cox analysis, worsening of PDS and remodeling resulted independent predictors of events (both P < .01). Patients with both worsening of PDS and remodeling had the worst event-free survival (P <.001). CONCLUSION: In patients treated with primary PCI after AMI, worsening of PDS and remodeling are associated to higher risk of events at long-term follow-up. Gated stress MPS improves risk stratification in these patients.