Summed Difference Score Research Articles

P0702IMPAIRED MYOCARDIAL MICROCIRCULATION PERFUSION IN ASYMPTOMATIC STAGE 1-4 CHRONIC KIDNEY DISEASE PATIENTS WITH INTRARENAL ARTERIAL LESIONS

Abstract Background and Aims Even mild renal disease is a powerful cardiovascular (CV) risk factor. However, the association between these pathophysiological processes, especially in the early asymptomatic stage, remains unclear. This study aimed to explore the relationship of cardio-renal microvascular disease in asymptomatic stage 1-4 chronic kidney disease (CKD) patients without obstructive coronary artery disease (CAD). Method This study consisted of 243 asymptomatic patients with stage 1-4 CKD who had no obstructive CAD. We distinguished different degrees of severity of intrarenal arterial lesions according to Oxford classification. Myocardial microcirculation perfusion was measured using single-photon emission computed tomography (SPECT). The summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) were estimated with the standard 17-segment, 5-point scoring model. Coronary microvascular disease (CMD) was defined as abnormal SPECT MPI (SSS ≥4 or SDS≥2 on SPECT images) in the absence of obstructive CAD. Results The study subjects showed a stepwise increase in CMD severity with the aggravation of intrarenal arterial lesions; The SSS of no/mild/moderate/severe arterial lesions were 1.64±1.08, 2.56±1.35, 4.42±2.17, 6.48±3.52, respectively (all P<0.05); The SDS of no/mild/moderate/severe arterial lesions were 1.29±0.49, 1.75±0.56, 3.06±1.12, 4.16±1.85, respectively (all P<0.05). The percentage of subclinical CMD in CKD patients with intrarenal arterial lesions was significantly higher than those without arterial lesions (69.57% vs. 14.71%; P=0.01). Vice versa, the scores of intrarenal arterial lesions were significantly higher in patients who had myocardial perfusion defect (4.79±2.01 vs. 2.22±2.07, P=0.000), myocardial ischemia (3.69±2.16 vs. 2.35±1.69, P=0.001) compared to those without arterial lesions. Multiple regression analysis further supported renal arterioles hyalinization (OR=1.109, P=0.027) were independently associated with subclinical CMD in stage 1-4 CKD patients with no obstructive CAD. Conclusion This study demonstrated for the first time impaired myocardial microcirculation perfusion in asymptomatic stage 1-4 CKD patients with intrarenal arterial lesions. Renal arteriolar hyalinization may be a useful marker of the presence of CMD in CKD.

Preoperative nuclear stress testing in the very old patient population.

BACKGROUNDElderly patients awaiting moderate to high-risk surgery may undergo nuclear stress testing (NST) in order to evaluate their cardiovascular risk. The prognostic utility of such testing in the very elderly (≥ 85 years) has yet to be fully evaluated. Octogenarians and nonogenarians frequently have a number of concurrent conditions including a high rate of coronary disease, and therefore the prognostic value of NST for their preoperative risk assessment has been questioned. Our evaluation assesses the ability of nuclear stress testing to predict peri-operative cardiac outcomes in this patient population.AIMTo investigate the ability of NST to predict peri-operative cardiac outcomes in elderly patients awaiting moderate to high-risk surgery.METHODSPatients ≥ 85 years undergoing pre-operative NST were retrospectively evaluated. Patients undergoing low-risk surgery were excluded. Major adverse cardiac events (MACE) were considered any adverse event that occurred prior to discharge and included acute heart failure, arrhythmia, acute myocardial infarction, unstable angina, or death. Associations between patient risk factors, MACE, and the obtained results of the pre-operative stress testing, ejection fraction (< 40% or ≥ 40%), summed stress score (≤ 8, ≥ 9), and the summed difference score (≤ 0, > 0) were analyzed.RESULTSA total of 69 patients (mean age 88 ± 2.6 years, 31 males) underwent nuclear stress testing prior to surgery. There were 41 (60%) patients found to have an abnormal NST. Sixteen (23%) patients were noted to experience post-operative MACE. No significant associations between risk factors and MACE were noted. Patients with an abnormal NST and/or a summed stress score ≥ 9 were significantly (P < 0.01) more likely to develop peri-operative MACE.CONCLUSIONIndicated preoperative NST is useful to assess pre-operative risk in elderly patients ≥ 85 years undergoing moderate to high-risk surgery.

Impact of extracorporeal shockwave myocardial revascularization on the ischemic burden of refractory angina patients: a single photon emission computed tomography study.

Extracorporeal shockwave myocardial revascularization (ESMR) is a non-invasive treatment designed to improve symptoms in refractory angina (RA) patients. Enhanced perfusion through local vasodilation and neo-capillarization is postulated to be the mechanism of the observed clinical benefit. However, the impact of ESMR on the ischemic burden of RA patients has not been adequately assessed. One-hundred twenty-one consecutive RA patients suitable for ESMR were treated. Twenty-nine RA patients not suitable for treatment were clinically followed-up as a control group for clinical endpoints. ESMR-treated patients underwent baseline and 6-month single photon emission computed tomography (SPECT) to evaluate the changes in ischemic burden. The operator was blinded to the pre/post-treatment status of the SPECT exam. The primary endpoint was the difference in summed stress score (SSS) and summed difference score (SDS) between follow-up and baseline SPECTs. Secondary endpoints included the changes in Canadian Cardiovascular Society (CCS) angina class and nitroglycerin use between 6-month follow-up and baseline. Clinical endpoints were further compared between ESMR-treated patients and the control group. Following ESMR, a significant reduction in the ischemic burden was observed (follow-up SSS: 14.2±10 vs. baseline SSS: 21.2±9.42, P<0.0001; follow-up SDS: 4.6±5.9 vs. baseline SDS 10.2±7.9, P<0.0001) including less patients with moderate to severe ischemia (19% vs. 46% P<0.0001). CCS class and nitroglycerin use were significantly reduced (CCS: 1.5±0.6 vs. 2.7±0.6, P<0.0001; patients needing nitroglycerin: 24% vs. 64%, P<0.0001). When compared to the control group, CCS class reduction, nitroglycerin use and hospitalizations were significantly lower for ESMR treated vs. non-treated RA patients at 6-month follow-up. In this single-center cohort of RA patients undergoing ESMR treatment and serial myocardial perfusion imaging, ESMR was associated with a significant reduction in the ischemic burden. These findings provide a physiological rationale and mechanism for the observed clinical benefit.

Association of Posttraumatic Stress Disorder With Mental Stress–Induced Myocardial Ischemia in Adults After Myocardial Infarction

Posttraumatic stress disorder (PTSD) is prevalent among patients who survived an acute coronary syndrome and is associated with adverse outcomes, but the mechanisms underlying these associations are unclear. To evaluate the association of PTSD with mental stress-induced myocardial ischemia among individuals who survived a myocardial infarction (MI). This cross-sectional study included 303 patients aged 18 to 60 years enrolled from a university-affiliated network. Participants had a verified history of MI within 8 months. Data were collected from June 2011 to March 2016, and data analysis was conducted from March to June 2019. A clinical diagnosis of PTSD (lifetime and current) was obtained using the Structured Clinical Interview from the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition), and PTSD symptom subscales were assessed with the civilian version of the PTSD Symptom Checklist. Patients received technetium 99m-labeled sestamibi myocardial perfusion imaging at rest, with mental stress (ie, a speech task) and conventional stress (ie, exercise or pharmacologic). A summed difference score (ie, the difference between stress and rest scores) was used to assess ischemia under both stress conditions. Among 303 participants (148 [48.8%] women; 198 [65.3%] African American; mean [SD] age, 51 [7] years), the prevalence of PTSD was 14.5% (44 patients). Patients with PTSD had a higher rate of ischemia with mental stress than those without PTSD (12 of 44 [27.3%] vs 38 of 259 [14.7%]; P = .04) and more than twice the mean number of ischemic segments (1.2 [95% CI, 0.5-1.8] vs 0.5 [95% CI, 0.3-0.7]; P < .001), but there was no difference in conventional stress ischemia (10 of 44 [22.7%] vs 60 of 259 [23.2%]; P = .91). Increasing levels of PTSD symptoms were associated with higher odds of ischemia with mental stress (adjusted odds ratio [OR] per 5-point score increase, 1.18; 95% CI 1.04-1.35; P = .01) but not with conventional stress (adjusted OR per 5-point score increase, 1.05; 95% CI, 0.92-1.21; P = .47). Reexperiencing trauma was the symptom cluster most robustly associated with the presence of ischemia with mental stress (adjusted OR per 5-point score increase, 1.87; 95% CI 1.21-2.91; P = .005), followed by avoidance and numbing (adjusted OR per 5-point score increase, 1.51; 95% CI, 1.07-2.14; P = .02). In this study of young and middle-aged individuals with MI, with a large representation of women and patients from racial/ethnic minority groups, PTSD was associated with the development of myocardial ischemia with mental stress. A higher ischemic response to mental stress represents a potential pathway associating PTSD with adverse outcomes after MI.

Inter-reader variability of SPECT MPI readings in low- and middle-income countries: Results from the IAEA-MPI Audit Project (I-MAP)

BackgroundConsistency of results between different readers is an important issue in medical imaging, as it affects portability of results between institutions and may affect patient care. The International Atomic Energy Agency (IAEA) in pursuing its mission of fostering peaceful applications of nuclear technologies has supported several training activities in the field of nuclear cardiology (NC) and SPECT myocardial perfusion imaging (MPI) in particular. The aim of this study was to verify the outcome of those activities through an international clinical audit on MPI where participants were requested to report on studies distributed from a core lab. MethodsThe study was run in two phases: in phase 1, SPECT MPI studies were distributed as raw data and full processing was requested as per local practice. In phase 2, images from studies pre-processed at the core lab were distributed. Data to be reported included summed stress score (SSS); summed rest score (SRS); summed difference score (SDS); left ventricular (LV) ejection fraction (EF) and end- diastolic volume (EDV). Qualitative appraisals included the assessment of perfusion and presence of ischemia, scar or mixed patterns, presence of transient ischemic dilation (TID), and risk for cardiac events (CE). Twenty-four previous trainees from low- and middle-income countries participated (core participants group) and their results were assessed for inter-observer variability in each of the two phases, and for changes between phases. The same evaluations were performed for a group of eleven international experts (experts group). Results were also compared between the groups. ResultsExpert readers showed an excellent level of agreement for all parameters in both phase 1 and 2. For core participants, the concordance of all parameters in phase 1 was rated as good to excellent. Two parameters which were re-evaluated in phase 2, namely SSS and SRS, showed an increased level of concordance, up to excellent in both cases. Reporting of categorical variables by expert readers remained almost unchanged between the two phases, while core participants showed an increase in phase 2. Finally, pooled LVEF values did not show a significant difference between core participants and experts. However, significant differences were found between LVEF values obtained using different software packages for cardiac analysis. ConclusionsIn this study, inter-observer agreement was moderate-to-good for core group readers and good-to-excellent for expert readers. The quality of reporting is affected by the quality of processing. These results confirm the important role of the IAEA training activities in improving imaging in low- and middle-income countries.

Myocardial Ischemia Correlates with Right Ventricular Dysfunction in Patients with Noncompaction Cardiomyopathy

Noncompaction cardiomyopathy (NCM) results from an arrest of the myocardial compaction process in the embryonic period, leading to the impaired formation of the microvasculature. Predominantly left ventricle is affected, however right ventricle (RV) involvement and its functional impact in NCM remains undefined. We sought to analyze a potential correlation between myocardial ischemia and RV failure in this patient cohort. We enrolled 41 NCM patients (28 male, 13 female), aged 21 to 70 years. At baseline we performed echocardiography to measure RVID (RV inflow diastolic diameter), TAPSE (tricuspid annular plane systolic excursion), Sto (systolic tissue Doppler velocity on tricuspid annulus) and RV FAC (fractional area change). Significant myocardial ischemia was defined as summed difference score (SDS)≥2 on myocardial SPECT at rest and on stress. Myocardial ischemia has been shown in 11 patients (27%, Group A), 30 patients showed no significant ischemic changes (73%, Group B). Groups did not differ in sex (82% male vs. 63% male in Group B, P=0.454), age (48±13 years vs. 47±15 years in Group B, P=0.855), kidney function (serum creatinine 76±11µmol/L vs. 81±26µmol/L in Group B, P=0.565) or liver function (serum bilirubine 12.4±7.1µmol/L vs. 13.3±6.5µmol/L in Group B, P=0.686). When compared to Group B, Group A had significantly lower FAC (30.7±7.7% vs. 44.9±10.2%, P<0.001), greater RVID (3.3±0.6cm vs. 2.9±0.5cm, P=0.016), lower TAPSE (1.9±0.6cm vs. 2.5±0.4cm, P<0.001), higher NT-proBNP levels (1691±1883pg/mL vs. 422±877pg/mL, P=0.006). There was a trend toward lower Sto (10.7±2.6cm/s vs. 12.4±2.4cm/s, P=0.081). Overall, higher SDS was associated with lower FAC (r=-0.51, P=0.006), higher RVID (r=0.41, P=0.032), lower TAPSE (r=-0.49, P=0.008) and higher levels of NT-proBNP (r=0.66, P<0.001). In patients with NCM myocardial ischemia appears to correlate with larger RV size and worse RV function.

Impairment of myocardial perfusion correlates with heart failure severity in patients with non-compaction cardiomyopathy.

ABSTRACTAimsNon‐compaction cardiomyopathy (NCM) is a congenital heart disease characterized by an arrest of the myocardial compaction process. Although NCM patients have impaired formation of microvasculature, the functional impact of these changes remains undefined. We sought to analyse a potential correlation between myocardial ischemia and heart failure severity in NCM patients.Methods and resultsWe enrolled 41 NCM patients (28 male and 13 female), aged 21–70 years. In all patients, we have determined left ventricular end‐diastolic volume (LVEDV), left ventricular ejection fraction (LVEF), and global longitudinal strain (GLS) by echocardiography. At the same time, serum levels of N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) have been measured, and myocardial single‐photon emission computed tomography at rest and on stress was used to define significant myocardial ischemia defined as summed difference score ≥ 2. Myocardial ischemia has been demonstrated in 11 patients (27%, Group A), and 30 patients showed no significant ischemic changes (73%, Group B). The groups did not differ in sex, age, kidney, or liver function. When compared with Group B, Group A had significantly lower LVEF (35 ± 15% in Group A vs. 53 ± 11% in Group B, P < 0.001), higher LVEDV (188 ± 52 mL vs. 136 ± 52 mL, P = 0.007), lower GLS (−9.9 ± 5.2% vs. −14.5 ± 4.1%, P = 0.001), and higher NT‐proBNP levels (1691 ± 1883 pg/mL vs. 422 ± 877 pg/mL, P = 0.006). Overall, higher summed difference score was associated with lower LVEF (r = −0.48, P = 0.001), higher LVEDV (r = 0.39, P = 0.012), lower GLS (r = 0.352, P = 0.024), and higher levels of NT‐proBNP (r = 0.66, P < 0.001).ConclusionsThe presence of myocardial ischemia in patients with NCM is associated with worse left ventricular function, dilation of the left ventricle, and more pronounced neurohumoral activation.

Prognostic Significance of the Residual SYNTAX Score and Ischemic Reduction Detected with Nuclear Cardiology for Prediction of Major Cardiac Events after Revascularization.

Objective There is no report on the risk stratification of major cardiac events (MCEs) with a combination of the Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) score and ischemic reduction detected with rest 201Tl and stress 99mTc-tetrofosmin myocardial perfusion single-photon-emission computed tomography (SPECT) after revascularization in Japanese patients with coronary artery disease (CAD). Methods This was a retrospective study. The patients were followed up to confirm their prognosis for at least one year. Ischemia was evaluated based on the summed difference scores converted to the percentage of the total myocardium Safety Data Sheet (SDS%). The SYNTAX score and SDS% were calculated before and after revascularization. The endpoint was the occurrence of MCEs. Patients Study subjects were 293 patients who had a ≥75% stenotic lesion detected with coronary angiography following confirmation of ≥5% ischemia with SPECT, underwent revascularization, and thereafter received a re-evaluation with SPECT and coronary angiography. Results During the follow-up, 25 patients experienced MCEs of cardiac death (n=2), non-fatal myocardial infarction (n=3), and unstable angina pectoris (n=20). A receiver operating characteristic analysis indicated that the best cut-off values of the residual SYNTAX score and ΔSDS% were 12 and 5%, respectively, for the prediction of MCEs. The patients with a low residual SYNTAX score (<12) and high ΔSDS% (≥5%) had the best prognosis, while those with a high residual SYNTAX score (≥12) and low ΔSDS% (<5%) had the worst prognosis. Conclusion The combination of the residual SYNTAX score and ischemic reduction detected with nuclear cardiology is useful for predicting MCEs after revascularization.

Abstract MP06: Everyday Discrimination And Mental Stress-induced Myocardial Ischemia In Young Women Post-mi

Objectives: Mental stress-induced myocardial ischemia (MSIMI) is a transient myocardial ischemic response to mental stress. Women are about two times more likely to develop MSIMI compared to men, which could potentially explain their worse morbidity and mortality after myocardial infarction (MI). We sought to examine the associations between experiences of everyday discrimination, as a gender-related stressor, and both MSIMI and conventional (exercise/pharmacologic)-induced myocardial ischemia among young survivors of MI. Hypothesis: Reports of everyday discrimination are associated with a higher prevalence of MSIMI, but not conventional ischemia in those with recent MI; furthermore, this relationship is stronger among young women compared to men. Methods: We studied 295 post-MI patients (145 women, 150 men) aged 25-61 years. Participants underwent single-photon emission computed tomography (SPECT) perfusion imaging at rest, after mental stress, and after exercise/pharmacological stress. Perfusion defect scores of myocardial segments were summed, with the summed difference score between stress and rest scores used to determine the presence of ischemia under both stress conditions. The Everyday Discrimination Scale (EDS) was assessed via questionnaire and used to measure exposure to experiences of discrimination (possible range 1-4). Results: EDS scores ranged from 1-3.8 (mean 1.7; SD 0.6). After adjustment for sociodemographic and cardiovascular risk factors, indicators of MI severity and symptoms of depression, each one point increase in average exposure to everyday discrimination (more frequent exposure) was associated with a doubling of odds of MSIMI (OR=2.46 [1.21 – 5.00]), but was not associated with exercise/pharmacological-induced ischemia (OR=0.75 [0.41 – 1.36]). These results were more robust among women, who demonstrated a nearly four-fold increase in odds of MSIMI with each one-point increase in average discrimination score compared to a two-fold increase among men, however there was no evidence of interaction by gender. Conclusion: Among young post-MI patients, experiences of everyday discrimination were positively associated with risk of MSIMI, but not associated with conventional stress ischemia. The risk of MSIMI tended to be greater among women than men, potentially implicating discrimination in triggering a physiological response to which women are particularly vulnerable.

Better characterization of dipyridamole-induced myocardial stunning by systolic wall thickening. A gated perfusion SPECT study

Aim and PatientsThe aim of the present study was to assess the additional value of systolic wall thickening to myocardial perfusion in diagnosing myocardial stunning induced by dipyridamole infusion. We selected 52 ischemic patients (43 males; mean age 65.5 ± 7.64), with CAD documented by angiography. Ischemia was defined as a summed difference score ≥ 5. All patients underwent a 2-day gated perfusion SPECT protocol. The patients received a dose of 740 MBq of 99mTc-tetrofosmin after stress and at rest. ResultsThe post-stress LVEF was significantly lower than rest LVEF (48.3% ± 14.5% vs. 50.7% ± 15%; P = 0.0001). The wall thickening summed difference score was 3.97 ± 3.84 (P = 0.0001). At a multivariate regression analysis, only WT-SDS as independent variable was significantly correlated with myocardial ischemia (SDS) (P = 0.001). We divided patients according to SDS in those with mild (SDS < 8) and severe (SDS ≥ 8) ischemia. WT-SDS, but not ∆LVEF, was significantly different between groups. ConclusionsWT-SDS showed a better correlation with the degree of ischemia than the depression in the global function of the left ventricle. It allowed to better identify the stunning phenomenon in patients submitted to pharmacological stress.

Utility of fractional flow reserve in moderate in-stent re-stenosis and jailed side branches and comparison of fractional flow reserve with single-photon emission computed tomography-myocardial perfusion imaging in native coronary artery stenosis

Background: Functional flow reserve (FFR) is used to determine functional significance of coronary artery stenosis. FFR demonstrated discrepancy between angiographic and functional significance of jailed side branches (JSBs) as well as moderate in-stent restenosis (ISR), with only minority of such lesions having functional significance. An attempt was made to study the utility of FFR and comparison of FFR with single-photon emission computed tomography-myocardial perfusion imaging (SPECT-MPI) in native coronary artery stenoses. Methods: A total of 101 lesions in 79 patients with stable ischemic coronary artery disease were subjected to FFR and SPECT-MPI including native as well as ISR and JSB. Relation between FFR and perfusion imaging was analyzed quantitatively. Sensitivity, specificity, positive predictive value, and negative predictive value were used for diagnostic accuracy. Results: FFR was ≤≤ 0.75 in majority of the lesions having >70% stenosis. Most of the lesions having reversible perfusion defect had FFR ≤≤ 0.80. There was a significant negative correlation between summed difference score (SPECT-MPI) with FFR value. As FFR value decreased, summed difference score increased. Sensitivity and specificity did not differ much when FFR cutoff was taken as 0.75 or 0.80. Conclusion: There was a significant negative correlation between FFR and sum difference score (SPECT-MPI). Sensitivity and specificity of SPECT-MPI did not differ much when FFR value cutoff was taken as 0.75 or 0.80.

1172 Predictive value of coronary artery calcium score for myocardial ischaemia in positron emission tomography

Abstract Funding Acknowledgements This study received no funding. Introduction Coronary artery calcium score (CACS) is an excellent predictor of long-term adverse cardiac events. However, little is known about its value and thresholds for immediate prediction of myocardial ischaemia. Purpose We tested the ability of CACS to predict myocardial ischaemia in patients with positron emission tomography (PET). In particular, we assessed the negative predictive value (NPV) of low CACS and the positive predictive value (PPV) of high CACS for myocardial ischaemia. Methods All consecutive patients undergoing 82Rb PET myocardial perfusion imaging with CACS from October 2016 to January 2019 at our centre were enrolled. Patients with known coronary artery disease (CAD) were excluded. Ischaemia was defined as a summed difference score (SDS) ≥4 in PET, and severe ischaemia as SDS ≥8 or transient ischaemic dilation. CACS was measured from low-dose computed tomography (CT) scans using the Agatston method. Receiver operating characteristic (ROC) analysis was used to calculate areas under the curves (AUC, with 95% confidence interval) and to assess sensitivity, specificity, PPV and NPV of CACS for ischaemia at pre-specified cut-offs (0, 100, 400, and 1000 Agatston units [AU]). Multivariate logistic regression was used to assess the predictive ability of CACS with clinical and ECG data, using odds ratios (OR, with 95% confidence interval). Prediction models were generated with propensity scores for CACS and clinical data with ECG, and compared using AUC. Results Of 1833 patients, 927 were included, all with CACS and 82Rb PET, without known CAD. Mean age was 64.3 ±11.1 years and median CACS was 55 AU (interquartile range 359). In PET, 179 patients (19.3%) had ischaemia and 87 (9.4%) severe ischaemia. To predict ischaemia, CACS had an AUC of 0.82 (0.79-0.84) and was superior to the clinical and ECG data model (AUC 0.68 [0.65-0.71], P &amp;lt; 0.0001 vs. CACS, Figure 1). For ischaemia, CACS 0 AU had 97% sensitivity and 98% NPV, and CACS 100 AU 81% sensitivity and 94% NPV. But CACS 1000 AU had 94% specificity and 60% PPV. Results were similar for severe ischaemia, with an AUC of 0.81 for CACS (0.79-0.84) and superiority over the clinical and ECG data model (AUC 0.74 [0.71-0.77], P = 0.018 vs. CACS). For severe ischaemia, CACS 0 AU had 98% sensitivity and 99% NPV, and CACS 100 AU 85% sensitivity and 98% NPV. But CACS 1000 AU had 90% specificity and 30% PPV. In multivariate analysis, CACS was the strongest predictor of ischaemia (OR 1.14 [1.11-1.17] by 100 AU, P &amp;lt; 0.0001) and made all clinical and ECG data nonsignificant. Conclusion CACS is a valuable predictor of myocardial ischaemia in PET. In particular, CACS ≤100 AU has an excellent NPV and CACS ≥1000 a good PPV for myocardial ischaemia. These findings can be useful to assess the need for additional cardiac testing after a chest CT showing coronary calcifications and to support the interpretation of borderline myocardial perfusion results. Abstract 1172 Figure 1: Prediction of ischaemia

Role of stress in dynamic single-photon emission computed tomography with myocardial perfusion reserve determination in assessing the severity of coronary artery stenosis

Aim. To assess the role of global and selected scintigraphic scores of myocardial perfusion, blood flow and reserve in the anatomical and functional significance of coronary artery (CA) stenosis.Material and methods. The double-blind comparative study included 23 patients (mean age 61,2±6,8 years, 12 (52%) women, 11 (48%) men). All patients underwent stress dynamic single-photon emission computed tomography (SPECT) with adenosine triphosphate (ATP) (140 µg/kg/min in 6 minutes). Myocardial perfusion disorders were assessed by a semi-quantitative method, the total Summed Stress Score (SSS), the Summed Rest Score (SRS), and the Summed Difference Score (SDS) were determined. Global (g) and regional (r) myocardial perfusion (MP) were evaluated; myocardial perfusion reserve (MPR) was calculated as the ratio of MP at stress and at rest. Coronary angiography (CAG) was performed within 1 week after SPECT, the amount of CA narrowing was evaluated by diameter. Stenoses &gt;50% were considered anatomically significant. The assessment of the fractional flow reserve (FFR) was performed by the ratio of the mean intracoronary pressure at the CA ostia to the pressure distal to the stenosis at the ATP infusion peak. FFR ≤0,80 was considered a sign of hemodynamically significant stenosis. Results. Neither regional nor global scintigraphic scores reflecting myocardial perfusion showed statistical significance as markers of CA stenosis &gt;50%. Among perfusion markers, only SSSg (&gt;4) showed good sensitivity and specificity in the diagnosis of hemodynamically significant (FFR ≤0,80) stenoses (AUC 0,76; p=0,002; sensitivity 81,8%, specificity 83,3%). The following regional flow scores allowed identification of hemodynamically significant CA: stress MPr ≤0,54 ml/min/g (AUC 0,8; p=0,0003; sensitivity 57%, specificity 92%) and MPR ≤1,5 (AUC 0,86; p&lt; 0,0001; sensitivity 71,4%, specificity 92,8%).Conclusion. It is proved that global and regional scintigraphic scores of MP and MPR are sensitive and specific markers of hemodynamically significant (FFR ≤0,80) coronary stenosis. It can be more useful for localization diagnosis of the lesion than standard SPECT.

Highlights From the Circulation Family of Journals.

Highlights From the Circulation Family of Journals.

Prognostic utility of splenic response ratio in dipyridamole PET myocardial perfusion imaging

BackgroundCardiac magnetic resonance perfusion studies with adenosine stress have shown that splenic response can identify patients with inadequate pharmacologic stress. We investigate the incremental prognostic impact of splenic response ratio (SRR) in patients with normal Rubidium (Rb)-82 PET myocardial perfusion imaging (MPI). MethodsConsecutive patients undergoing dipyridamole Rb-82 PET MPI for the evaluation of coronary artery disease were screened. Spleen and liver Rb-82 activity was measured and the SRR was calculated: SRR = (Spleen stress/Liver stress)/(Spleen rest/Liver rest). Major adverse cardiac events (MACE) were determined at 1 year of follow-up in patients with normal summed stress score and normal summed difference score. ResultsOf the 839 patients screened, the spleen was visualized in 703 (84%) of scans. There was significantly higher MACE observed in splenic non-responders vs splenic responders in both the normal SSS (7.8% vs 2.9%, P = .027) and the normal SDS groups (7.4% vs 2.2%, P = .014). In multivariate analysis in patients with normal SDS, splenic response was a significant, independent predictor of MACE (HR 2.97, 95% CI 1.10 to 8.04, P = .033). ConclusionsSRR is a novel imaging metric to identify patients with sub-maximal vasodilator stress and an incremental prognostic marker in patients with normal SDS and SSS (Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT01128023).

P3359Myocardial flow reserve using 13N ammonia PET for detection of cardiac allograft vasculopathy in heart transplant patients

Abstract Purpose Risk stratification and early detection of cardiac allograft vasculopathy (CAV) are essential in heart transplantation patients. CAV is associated with poor outcome in the chronic phase after heart transplantation. CAV presents a diffuse vascular involvement and has been difficult to noninvasively diagnose by the lack of a sensitive method to detect developing vascular pathology in the allograft. The present study investigates the ability of 13N-ammonia PET for detection of CAV in heart transplant patients. Methods Data of adenosine-stress 13N-ammonia PET imaging for thirty-one patients (mean age, 39 years-old) after 11 + 7 years from transplant was analyzed. Five patients had undergone percutaneous coronary intervention (PCI), and the remaining 26 patients had no history of definite myocardial ischemia. Myocardial flow was generated from the time activity curve of left ventricle input and myocardial uptake using 3-compartment model and the first 2 minutes' dataset of list-mode acquisition. Global - myocardial flow reserve (MFR) was calculated by stress to rest flow ratio. Patient with global-MFR &lt;2.0 was defined as significant decrease. Summed difference score (SDS) was used as an estimate for the extent of ischemia, and the patient showing SDS &gt;2 was identified as those having significant ischemia. Results The mean Global-MFR of our subjects were 2.3 (1.2 to 3.9). MFR using 13N-ammonia PET significantly decreases in one third of heart transplant patients in chronic stage. Eleven patients with Global-MFR &lt;2.0 (35%) were observed, and eight of them had no history of clinical myocardial ischemia. The proportion of patients with a history of PCI is 18% in patients with Global-MFR &lt;2.0 (vs 5%, p=0.210). Moreover, there were eight patients with SDS &gt;2 (26%) including three patients having a history of PCI. The proportion of patients with a history of PCI tends to be high with SDS &gt;2 (38% vs 9%, p=0.056). Conclusion This modality using 13N ammonia PET is useful for easily detection of CAV before manifestation of symptomatic myocardial ischemia in heart transplant patients.

P3355Stress-induced left ventricular dyssynchrony predicts future cardiac events in patients with known or suspected coronary artery disease

Abstract Background Prognostic value of stress induced left ventricular (LV) dyssynchrony has not been fully understood. The aim of this study was to evaluate the possible impact between cardiovascular events and stress induced worsening LV dyssynchrony. Methods and results One hundred and eighty consecutive subjects with known or suspected coronary artery disease (CAD) (142 men, mean age 68±12 years) underwent both gated myocardial single photon emission computed tomography (SPECT) with 99mTc-sestamibi or tetrofosmin according to a standard same day stress-rest protocol and coronary angiography or coronary computed tomography. The summed difference score (SDS) was calculated in every subjects. LV ejection fraction (EF) and phase Entropy at after stress and rest were determined by cardioREPO software. We determined %ΔEntropy = (stress Entropy - rest Entropy)/rest Entropy x100, as an indicator of stress-induced LV dyssynchrony. In the study population, the mean SDS was 2.7±3.9 and LVEF was 58±16%, stress and rest Entropy were 0.62±0.15 and 0.57±0.13, respectively. %ΔEntropy was higher in patients with CAD than in those without CAD (3.3±11.5 vs. 10.2±15.0, respectively). Moreover, there was a strict correlation between the presence of CAD and %ΔEntropy, indicator of stress induced LV dyssynchrony (non-CAD vs. CAD and/or 1 vessel disease vs. multivessel disease: 4.3±12.5 vs. 8.8±15.6 vs. 12.7±14.3, respectively. p&lt;0.05) We examined all study subjects and they were divided into 2 groups by cut off value of the %ΔEntropy constructed with receiver operating characteristic curve (=15.4). Kaplan-Meier analysis revealed that future cardiovascular event rate was significantly higher in %ΔEntropy &gt;15.4 group (20/57) than in %ΔEntropy &lt;15.4 group (24/123) (Log-rank p&lt;0.01). On the other hand, summed stress score and SDS were no significant differences between 2 groups. However, SDS was higher in patients with future cardiovascular event than in those without cardiovascular event (4.4±5.4 vs. 2.2±3.2, respectively. p=0.001). Conclusion In patients with known or suspected CAD, stress-induced worsening LV dyssynchrony may predict the presence of CAD and future cardiac events. Acknowledgement/Funding None

Performance of Traditional Pretest Probability Estimates in Stable Patients Undergoing Myocardial Perfusion Imaging.

The yield of myocardial perfusion imaging is low in contemporary patients with suspected coronary artery disease (CAD) selected based on American College of Cardiology Foundation/American Heart Association pretest probability estimate. We compared traditional pretest estimates of CAD probability with the prevalence of abnormal myocardial perfusion single-photon emission computed tomography (MPS). This was a cohort study from a single academic center. Consecutive stable patients without known CAD referred for stress MPS for suspected CAD between 2004 and 2011 were identified (n=15 777). Angina typicality was determined using standard criteria. Abnormal MPS perfusion was defined as a summed stress score ≥4, ischemia as summed stress score ≥4 and summed difference score ≥2, and extensive ischemia as summed difference score ≥8 using a standard, 17-segment model of the left ventricle. The pretest probability of CAD was determined using the American College of Cardiology Foundation/American Heart Association criteria. Overall, 14% (n=2177) of patients had abnormal MPS of whom 11% (n=1698) had ischemia and 4% (n=684) extensive ischemia. In patients with chest pain who underwent treadmill MPS (n=4764), only 27% reported angina on the treadmill. Typical angina was associated with the highest prevalence for positive MPS (33% in men and 14% in women), ischemia (30% in men and 12% in women), and extensive ischemia (22% in men and 4% in women) when compared with other symptom categories. Prevalence of MPS abnormality was substantially lower than expected based on pretest probability estimates across most sex and age groups. In multivariable analysis, the pretest probability estimate was not an independent predictor of abnormal MPS. Traditional estimates of pretest probability of CAD are not predictive of MPS perfusion abnormality and overestimate its prevalence in stable patients.

Impact of renin–angiotensin–aldosterone system polymorphisms on myocardial perfusion: Correlations with myocardial single photon emission computed tomography-derived parameters

BackgroundRenin–angiotensin–aldosterone system (RAAS) has an important role in atherosclerosis. We investigated the effects of six RAAS gene polymorphisms on myocardial perfusion. Methods and ResultsWe examined 810 patients with known or suspected coronary artery disease (CAD) using stress–rest myocardial single-photon emission computed tomography. Summed stress score (SSS), summed rest score (SRS), summed difference score (SDS), transient ischemic dilation (TID), and lung/heart ratio (LHR) were recorded. The following gene polymorphisms were investigated: angiotensin-converting enzyme (ACE) insertion/deletion (I/D), angiotensinogen (AGT) M235T and T174M, angiotensin II type 1 receptor (AT1R) A1166C, renin (REN) C5312T, and angiotensin II type 2 receptor (AT2R) C3123A. The heterozygotes or homozygotes on ACE D allele were 7.54 times more likely to have abnormal SSS, while the AGT (T174M) heterozygotes were 5.19 times more likely to have abnormal SSS. The homozygotes of ACE D had significantly higher values on TID and LHR, while the AGT (T174M) heterozygotes had higher values on TID. The AT1R heterozygotes had greater odds for having SSS ≥ 3. The patients carried AT1R homozygosity of C allele had significantly higher values on TID, while heterozygotes of AT1R had significantly higher values on LHR. ConclusionsAmong the polymorphisms investigated, ACE D allele had the strongest association with abnormal myocardial perfusion.

The effect of cardiac shock wave therapy on myocardial function and perfusion in the randomized, triple-blind, sham-procedure controlled study

BackgroundRecent triple-blind sham procedure-controlled study revealed neutral effects of the cardiac shock wave therapy (CSWT) on exercise tolerance and symptoms in patients with stable angina. Current data about the effects of CSWT on global and regional myocardial contractility and perfusion is limited. Hereby we report the results of an imaging sub-study that evaluated the capacity of CSWT to ameliorate myocardial ischemia induced during dobutamine stress echocardiography (DSE) and cardiac single photon emission computed tomography (SPECT).MethodsProspective, randomized, triple-blind, sham procedure-controlled study enrolled 72 adult subjects who complied with defined inclusion criteria. The subjects were assigned to the OMT + CSWT and the OMT + sham procedure study groups with 1:1 ratio. Application of the CSWT covered all segments of the left ventricle. Imaging ischemia tests were performed in 59 study patients: DSE and SPECT before the CSWT treatment and after 6 months, with DSE carried out additionally at 3 months after randomization. Co-primary endpoints of the study were: change in wall motion score index (WMSI), representing the stress-induced impairment of regional myocardial function, and change in summed difference score (SDS), representing the amount of perfusion defect.ResultsOMT + CSWT and OMT + sham procedure study groups included 30 and 29 patients, respectively. Regional myocardial contractility during DSE significantly improved at 3 months follow-up in OMT + CSWT group compared to baseline as shown by WMSI at stress (1.4 ± 0.4 vs 1.6 ± 0.4, p = 0.001), but not in OMT + sham procedure group (1.5 ± 0.3 vs 1.6 ± 0.4, p = 0.136). The difference in stress DSE results between both study groups disappeared after 6 months. SPECT results demonstrated a significant reduction of inducible ischemia in OMT + CSWT group compared to OMT + sham procedure group at 6 months follow-up (SDS dropped from 5.4 ± 3.7 to 3.6 ± 3.8 vs 6.4 ± 5.9 to 6.2 ± 5 respectively, p = 0.034).ConclusionsCardiac shock wave treatment showed the ability to reduce stress-induced myocardial ischemia, as assessed by wall motion abnormalities and perfusion defects, compared to sham procedure.Trial registrationClinicaltrials.gov (NCT02339454). The trial was registered retrospectively on 12 January 2015.