Stress Ejection Fraction Research Articles

Artificial intelligence-derived stress ejection fraction in stress cardiac magnetic resonance with dipyridamole: bridging past insights with future innovations.

Artificial intelligence-derived stress ejection fraction in stress cardiac magnetic resonance with dipyridamole: bridging past insights with future innovations.

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

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

Indicators of abnormal PET coronary flow capacity in detecting cardiac ischemia.

Coronary flow capacity (CFC) categorizes severity of left ventricular (LV) ischemia by PET myocardial blood flow (MBF). Our objective was to correlate abnormal CFC with other indicators of regional ischemia. Data were examined retrospectively for 231 patients evaluated for known/suspected CAD who underwent rest and regadenoson-stress 82Rb PET/CT. MBF and myocardial flow reserve (MFR) were quantified, from which CFC was categorized as Normal CFC (1), Minimally reduced (2), Mildly reduced (3), Moderately reduced (4), and Severely reduced (5) for the three main arterial territories as well as globally. Relative perfusion summed stress score (SSS) and systolic phase contraction bandwidth (BW) were assessed. Accuracy to detect arteries with CFC ≥ 4 was highest for a Regional Index combining SSS and BW (88 ± 3%). A Global Index formed from stress ejection fraction, SSS and BW was the most accurate means of identifying patients with global CFC ≥ 4 (84 ± 3%). Arteries with abnormal CFC derived from absolute myocardial blood flow measurements are accurately identified by composite parameters combining regionally aberrant relative perfusion patterns and asynchrony.

Clinical implications of compromised 82Rb PET data acquisition

BackgroundWe wished to document the prevalence and quantitative effects of compromised 82Rb PET data acquisitions on myocardial flow reserve (MFR). Methods and ResultsData were analyzed retrospectively for 246 rest and regadenoson-stress studies of 123 patients evaluated for known or suspected CAD. An automated injector delivered pre-determined activities of 82Rb. Automated quality assurance algorithms identified technical problems for 7% (9/123) of patients. Stress data exhibited 2 instances of scanner saturation, 1 blood peak detection, 1 blood peak width, 1 gradual patient motion, and 2 abrupt patient motion problems. Rest data showed 1 instance of blood peak width and 2 abrupt patient motion problems. MFR was lower for patients with technical problems flagged by the quality assurance algorithms than those without technical problems (1.5 ± 0.5 versus 2.1 ± 0.7, P = 0.01), even though rest and stress ejection fraction, asynchrony and relative myocardial perfusion measures were similar for these two groups (P > 0.05), suggesting that MFR accuracy was adversely affected by technical errors. ConclusionIt is important to verify integrity of 82Rb data to ensure MFR computation quality.

Implementation of a Myocardial Perfusion Imaging Risk Algorithm to Inform Appropriate Downstream Invasive Testing and Treatment.

To risk stratify patients undergoing single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) in accordance with appropriate use criteria for referral to coronary angiography, we developed a risk classification algorithm incorporating appropriate use criteria-defined risk features. We evaluated the association between this algorithm with downstream angiography, revascularization, and all-cause mortality. We studied consecutive patients who underwent SPECT-MPI from January 1, 2015, to December 31, 2017, and assigned a scan risk of low, intermediate, high, or indeterminate. With this stratification, we assessed referral for angiography and revascularization within 3 months of SPECT-MPI and intermediate-term mortality. Among 12 799 patients, the mean age was 66 years, and a majority were men (56.8%). Most patients were low risk (83.6%) followed by intermediate (9.9%) and high risk (5.2%). Compared with low-risk patients, intermediate- and high-risk patients were more frequently referred for angiography (14.8% and 13.6% versus 2.0%; P<0.001) and revascularization (7.7% and 6.8% versus 0.7%; P<0.001). In 1008 propensity-matched patients, scan risk was independently associated with angiography after adjustment for ischemia, scar, or stress ejection fraction. At a mean follow-up of 2.3 years, mortality was higher with increased scan risk (high, 10.4%; intermediate, 7.1%; low, 4.1%; P<0.001). Compared with low scan risk, intermediate (hazard ratio, 1.37 [95% CI, 1.09-1.72]; P=0.008) and high scan risk (hazard ratio, 1.98 [95% CI, 1.53-2.56]; P<0.001) were associated with mortality in multivariable analysis. Similar findings were observed for those undergoing pharmacological and exercise SPECT-MPI with comparatively worse prognosis among pharmacological patients. This appropriate use criteria-derived risk classification algorithm for SPECT-MPI guided referral for coronary angiography and revascularization and was significantly associated with mortality. This algorithm may serve as an important tool to reaffirm appropriate use criteria and direct management of patients with stable ischemic heart disease undergoing stress testing.

Increased myocardial fat supply improves cardiac energetics and function in heart failure

Abstract Introduction The failing heart is starved of energy, in part accounting for its contractile dysfunction. Reduced uptake of fat and sugar required for energy production has frequently been demonstrated in heart failure, therefore altering metabolism of glucose and/or fat is therefore attractive as a therapy. We hypothesized increasing glucose supply would be beneficial over increasing fat supply so measured ATP usage (via PCr/ATP ratio and flux through creatine kinase) and cardiac function during fat emulsion infusion or euglycaemic hyperinsulinaemic clamp. Methods 11 patients with a diagnosis of heart failure and nonischaemic cardiomyopathy were recruited, mean age 66 (range 49–80), mean BMI 27.7 (range 21.3–37.5), F:M 3:8, 3 diabetic and 8 non-diabetic. On the first visit they had a baseline cardiac magnetic resonance (CMR), collecting cardiac volumes and function, then were randomised to receive either fat infusion or euglycaemic clamp. Following an hour of infusion, CMR was repeated followed by 31P cardiac magnetic resonance spectroscopy, then a dobutamine stress sequence at 65% maximum heart rate. They received the alternate infusion at the next visit. Results Data was normally distributed. Baseline ejection fraction was 37±9%. PCr/ATP ratio was greater with the fat infusion compared to euglycaemic clamp (1.82±0.26 vs 1.68±0.24, p=0.04). Fat emulsion infusion also brought about a greater ejection fraction increase over the baseline, compared to the euglycaemic clamp in which there was little difference (+5.3±5.3% vs −0.6±3.1%, p=0.004). Calculated cardiac work was greater in the fat infusion group than the Insulin/glucose group (682±156 L.mmHg/min vs 581±85 L.mmHg/min, p=0.009). There was no significant difference in creatine kinase first order rate constant (fat infusion 0.2±0.09/s vs euglycaemic clamp 0.16±0.07/s, p=0.32) nor creatine kinase flux (fat infusion 1.85±0.92 μmol/g/s vs euglycaemic clamp 1.46±0.58 μmol/g/s, p=0.22). The increment in cardiac output on stress over baseline was not significantly different between arms (fat infusion +3.39±3.07 L/min vs euglycaemic clamp +3.08±2.57 L/min, p=0.42). The PCr/ATP ratio showed positive correlation with the stress ejection fraction (R2=0.656, p=0.001), but not with resting ejection fraction. Conclusions Increased supply of fat to the myocardium brought about improved contractility and cardiac energetics compared to an increased glucose supply. The increase in PCr/ATP ratio would imply (given ATP concentrations are kept constant in the myocardium) there is a greater availability of phosphocreatine, suggesting increased mitochondrial ATP synthesis. These results were unexpected as it has traditionally been thought that increased glucose metabolism would yield greater cardiac function in the failing heart. These data suggest targeting myocardial fat metabolism may provide novel treatments for cardiac dysfunction. Figure 1 Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Stress-Induced Mouse Model of the Cardiac Manifestations of Friedreich's Ataxia Corrected by AAV-mediated Gene Therapy.

Friedreich's ataxia (FA), an autosomal recessive disorder caused by a deficiency in the expression of frataxin (FXN), is characterized by progressive ataxia and hypertrophic cardiomyopathy. Although cardiac dysfunction is the most common cause of mortality in FA, the cardiac disease remains subclinical for most of the clinical course because the neurologic disease limits muscle oxygen demands. Previous FXN knockout mouse models exhibit fatal cardiomyopathy similar to human FA, but in contrast to the human condition, untreated mice become moribund by 2 months of age, unlike humans where the cardiac disease often does not manifest until the third decade. The study was designed to create a mouse model for early FA disease relevant to the time for which a gene therapy would likely be most effective. To generate a cardiac-specific mouse model of FA cardiomyopathy similar to the human disease, we used a cardiac promoter (αMyhc) driving CRE recombinase cardiac-specific excision of FXN exon 4 to generate a mild, cardiac-specific FA model that is normal at rest, but exhibits the cardiac phenotype with stress. The hearts of αMyhc mice had decreased levels of FXN and activity of the mitochondrial complex II/complex IV respiratory chain. At rest, αMyhc mice exhibited normal cardiac function as assessed by echocardiographic assessment of ejection fraction and fractional shortening, but when the heart was stressed chemically with dobutamine, αMyhc mice compared with littermate control mice had a 62% reduction in the stress ejection fraction (p < 2 × 10-4) and 71% reduction in stress-related fractional shortening (p < 10-5). When assessing functional cardiac performance using running on an inclined treadmill, αMyhc mice stayed above the midline threefold less than littermate controls (p < 0.02). A one-time intravenous administration of 1011 genome copies of AAVrh.10hFXN, an adeno-associated virus (AAV) serotype rh10 gene transfer vector expressing human FXN, corrected the stress-induced ejection fraction and fractional shortening phenotypes. Treated αMyhc mice exhibited exercise performance on a treadmill indistinguishable from littermate controls (p > 0.07). These αMyhc mice provide an ideal model to study long-term cardiac complications due to FA and AAV-mediated gene therapy correction of stress-induced cardiac phenotypes typical of human FA.

Thallium-201 is comparable to technetium-99m-sestamibi for estimating cardiac function in patients with abnormal myocardial perfusion imaging

We analyzed the left-ventricular functional data obtained by cardiac-gated single-photon emission computed tomography myocardial perfusion imaging (MPI) with thallium-201 (Tl-201) and technetium-99m-sestamibi (MIBI) protocols in different groups of patients, and compared the data between Tl-201 and MIBI. Two hundred and seventy-two patients undergoing dipyridamole stress/redistribution Tl-201 MPI and 563 patients undergoing 1-day rest/dipyridamole stress MIBI MPI were included. Higher mean stress ejection fraction (EF), rest EF, and change in EF (ΔEF) were noticed in the normal MPI groups by both Tl-201 and MIBI protocols. Higher mean EF was observed in the females with normal MPI results despite their higher mean age. Comparisons between the Tl-201 and MIBI groups suggested a significant difference in all functional parameters, except for the rest end diastolic volume/end systolic volume and ΔEF between groups with negative MPI results. For the positive MPI groups, there was no significant difference in all parameters, except for the change in end diastolic volume and change in end systolic volume after stress between both protocols. The Tl-201 provides comparable left-ventricular functional data to MIBI cardiac-gated single-photon emission computed tomography in patients with positive MPI results, and may therefore be undertaken routinely for incremental functional information that is especially valuable to this patient group.

Diabetes in acute coronary syndrome patients: do we see only the tip of the iceberg?

Aim of the study: To analyse the influence of glycoregulation in pts. with known or newly detected diabetes, on in-hospital morbidity/mortality in patients with acute coronary syndrome. Methods: randomly selected ACS patients were analysed for: stress glycaemia, HgbA1c, risk profile, lipid profile, SINTAX score, TIMI flow, LV function and in-hospital morbidity/mortality. We comparatively analysed pts. based on the level of HgbA1c (⩾ 6,5% vs 6.5%). Mean values of HgbA1c and stress glycaemia were as follows: NonD - 5.19±0.56 and 6.82±1.87; PD - 5.99±0.19 and 8.32±3.17; ND - 8.19±1.15 and 17.68.19±1.15; CD - 5.79±0.55 and 8.89±4.38; and UD - 9.36±1.33 and 16.23±6.24; (ANOVA p >0.000). No significant difference was found between NonD and CD pts., and between ND and UD (high in the last two), but there was significant difference in HgbA1c (p 0.000, Kappa agreement (0.516; sig p>0.000). TG levels were increased only in UD, and ND groups: 1.93±1.06, and 2.36±1.22, (ANOVA p=0.026, Tukey test ND vs NonD p=0.050; and vs PD p=0.016), without significant difference in other lipid fractions. Mean SINTAX score was 15.45±8.2, without significant inter-gorup differences. TIMI flow before PCI significantly differed across the groups, the lowest being in ND - 0.14±0.36 and PD - 1.13±1.42 pts. (group value 1.37±1.42; ANOVA p=0.001; Tukey test: NonD vs ND 0.000; and 0.043 vs CD). Mean EF was 51.51±8.5, without significant inter-group difference. 29 in-hospital events in 22 (19%) patients were registered: 7.7% arrhythmias, 6.9% heart failure, 3.4% GIT bleedings, and 2.6% CVI. In-hospital mortality was 4.3%. In multivariate logistic regression analysis, ejection fraction, stress glycaemia, and HgbA1c were identified as independent predictors of in-hospital outcome. Conclusion: High prevalence of unknown diabetes in ACS patients exists, leading to worse CAD, even in comparison with pts with known, well controlled diabetes. Stress glycaemia, HgbA1c and ejection fraction are independent predictors of in-hospital morbidity/mortality.

Major cardiac event risk scores estimated with gated myocardial perfusion imaging in Japanese patients with coronary artery disease

BackgroundA Heart Risk Table has been reported as the first risk score based on nuclear cardiology to predict cardiac event rates in Japanese patients. However, there are no risk scores estimating risk of major cardiac events (MCEs) except severe heart failure. MethodsWe retrospectively investigated 2579 patients with known or suspected coronary artery disease (CAD) who underwent rest 201Tl and stress 99mTc-tetrofosmin myocardial perfusion single photon emission computed tomography between October 2004 and March 2011 and who had data on a 3-year follow-up. The perfusion images were analyzed with 20 segments of a five-point visual scoring model to estimate summed defect scores. The endpoint was the onset of MCEs consisting of cardiac death, non-fatal myocardial infarction and unstable angina pectoris. ResultsDuring the 3-year follow-up, 171 patients (6.6%) experienced MCEs comprising cardiac death (n=78), non-fatal myocardial infarction (n=30), and unstable angina pectoris (n=63). The multivariate logistic regression analysis indicated age, diabetes, estimated glomerular filtration rate (eGFR), and summed stress scores (SSS) as independent predictors of the MCEs and age, stress ejection fraction, eGFR, and SSS as independent predictors of cardiac death. Those four predictors and coefficients corresponding to them were used to make two different risk equations: MCE risk (%/3 years)=1/{1+Exp[−(−3.176+0.018×age+0.602×diabetes−0.022×eGFR+0.051×SSS)]}×100 and cardiac death risk (%/3 years)=1/{1+Exp[−(−2.602+0.031×age−0.031×eGFR+0.038×SSS−0.029×stress ejection fraction)]}×100. ConclusionThe risk scores obtained from this study are useful to predict MCEs in Japanese patients with CAD and are expected to be useful for management and informed consent of high-risk CAD patients.

Patients with reduced heart rate response to adenosine infusion have low myocardial flow reserve in 13N-ammonia PET studies

To assess the effect of adenosine infusion by evaluating the relationship between heart rate (HR) response to adenosine and myocardial flow reserve (MFR) of remote regions supplied by normal coronary arteries in 13N-ammonia PET. Thirty-one consecutive subjects (20 known coronary artery disease patients, 4 chronic heart failure patients, and 7 normal volunteers) except cases having 3-vessel disease underwent rest and adenosine stress 13N-ammonia myocardial perfusion PET. Semi-quantitative, quantitative, and gated analyses were performed. Subjects were divided into two groups with regard to HR response to adenosine. Twenty-two subjects had normal HR response (peak/rest HR > 1.20), while reduced HR response (≤1.20) was observed in nine subjects. There were no differences in rest myocardial blood flow (MBF) of remote regions between the groups. Subjects with reduced HR response had significantly lower stress MBF and MFR of remote regions than those with normal HR response (stress MBF: 1.559 ± 0.517 vs. 2.279 ± 0.530, p = 0.004, MFR: 1.59 ± 0.36 vs. 2.35 ± 0.53, p = 0.001). There were no significant differences between the groups by means of semi-quantitative scoring. Rest and stress ejection fraction (EF) in the reduced HR response group was lower than that in the normal HR response group. In a multiple stepwise regression analysis, HR ratio, dyslipidemia, and Brinkman index were identified as predictors of the change in MFR of remote regions. Subjects with reduced HR response to adenosine had lower stress MBF and MFR of remote regions and lower EF. Moreover, HR response was one of the predictors of the change in MFR of remote regions.

Heart Rate Response to Dypiridamole Stress in Relation to Perfusion and Function during Gated Technetium Tc99 M Sestamibi Spect Study

Objectives: A mild decrease in blood pressure and increase in heart rate (HR) are considered normal hemodynamic responses to dipyridamole. In this study, we tried to investigate the relation between the responses of heart rate to dipyridamole stress test with left ventricular perfusion and function data obtained from myocardial perfusion scintigraphy. Methods: Forty consecutive patients undergoing dipyridamole stress Technetium - 99m (Tc 99m) Sesta MIBI gated myocardial perfusion single photon emission computed tomography (SPECT) at the nuclear cardiology Lab of the cardiology department of the main university hospital of Alexandria University were prospectively enrolled from July 2013 for 6 months. Dipyridamole was infused over 4 min and TC 99m Sesta MIBI was injected 2 min after the end of infusion. Blunted heart rate response to dipyridamole considered if the HR ratio (peak HR/rest HR) was 1.20 or less. Summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) for myocardial perfusion in addition to total perfusion defect TPD, ejection fraction and territory of perfusion defect were obtained.Patients were grouped according to HR response and groups were compared. A logistic regression analysis was used to determine independent predictors of reduced HR response. Results: Blunted heart rate response was found in 67.5 % of patients. Patients with abnormal heart rate response were more frequently had a history of diabetes mellitus (X2 = 4.01). High baseline heart rate (t = 1.9), low post stress ejection fraction (t = 3.21) and perfusion defect in left circumflex territory (X 2 = 4.01) was found in blunted heart rate response group more than normal group. Conclusion: Severe perfusion defectis associated with blunted heart rate group as left ventricular dysfunction is associated with reduced chronotropic response to dipyridamole.Diabetes mellitus and cardiac autonomic neuropathy may reflect higher baseline heart rate.

99mTc tetrofosmin myocardial perfusion scintigraphy in CAD. Performance with early and standard delayed acquisition and fractional flow reserve.

Early stress imaging (15 min after injection of the radiopharmaceutical) in 99mTc tetrofosmin myocardial perfusion scintigraphy (MPS) has been shown feasible in comparison to standard imaging after 45 minutes, but the effects on image quality and diagnostic accuracy ask for further evaluation. 97 patients (61 men, 36 women, age 69 ± 11 years) underwent both early (EA) and standard (SA) acquisition (after 14 ± 4 min and 43 ± 6 min, respectively) using 99mTc tetrofosmin gated SPECT with iterative reconstruction. Sub-diaphragmatic tracer activity and image quality was scored in a 4-point scale by blinded observers. Semiquantitative myocardial perfusion analysis was performed on a 17-segment model using standard cardiac quantification SPECT software (4 DM-SPECT). Stenoses of indeterminate haemodynamic significance were validated by measurement of fractional flow reserve (FFR). Extra-cardiac tracer activity was more commonly found in EA (43%) than in SA (38%), but without any diagnostic impact in > 95% of the patients. The mean summed stress score was significantly higher for early than standard imaging (6.4 ± 6.3 vs. 5.6 ± 6.1, p = 0.009). The amount of ischaemic area was not significantly different (EA: 9.1 ± 6.7 % vs. SA: 7.8 ± 6.9 %). The mean stress ejection fraction was 52 ± 11% (EA) compared to 55 ± 11 % (SA) (p = ns). FFR was inversely related to SDS at early (r = -0.704, p < 0.05) and standard (r = -0.678, p < 0.05) acquisition. All patients with a FFR < 0.8 (considered as hemodynamically significant stenoses) revealed a positive scan. Stress 99mTc tetrofosmin MPS with early acquisition is feasible and at least equally accurate when iterative reconstruction is applied.

High‐dose plasmid‐mediated VEGF gene transfer is safe in patients with severe ischemic heart disease (Genesis‐I). A phase I, open‐label, two‐year follow‐up trial

We aimed to assess safety and, secondarily, the efficacy of intramyocardial high-dose plasmid-vascular endothelial growth factor (VEGF) 165 (pVEGF165) gene transfer in no-option patients with coronary artery disease (CAD). Controlled trials of pVEGF165 in CAD have shown little benefit. One possible reason is shortness of dosage. We have shown in large mammalian models of chronic myocardial ischemia and acute myocardial infarction that intramyocardial pVEGF165 at doses significantly higher than those used in recent phase II trials is safe and efficacious on myocardial perfusion, left ventricular function, and infarct size limitation. Using an injection catheter, 10 patients with severe CAD not amenable for revascularization received 10 intramyocardial injections of 0.38 mg (total dose, 3.8 mg) pVEGF165 in zones exhibiting myocardial ischemia, as assessed by combined stress 99mTc-sestamibi single-photon emission computed tomography and stress echocardiography. No serious adverse events related to either VEGF or the injection procedure occurred over the 2-year follow-up. One patient suffered femoral artery thrombosis after a follow-up coronary angiography, successfully resolved with medical treatment. Six patients suffered uncomplicated coronary ischemic events during the second year follow-up. Angina functional class decreased from 2.6 ± 0.2 to 1.2 ± 0.3 (mean ± SEM, P < 0.05), quality of life increased from 56.9 ± 3.2 to 82.6 ± 2.4 (P < 0.05), the summed difference score of myocardial perfusion decreased from 13.4 ± 2 to 7.7 ± 1.8 (P < 0.04), and stress ejection fraction did not change (44.2 ± 3.6% to 47.8 ± 3.1%, P = NS). High-dose intramyocardial pVEGF165 is safe at 2 years follow-up in patients with severe CAD. The efficacy results observed must be taken cautiously given the uncontrolled, open-label study design.

139 CARDIAC TROPONIN-T MEASURED BY HIGH SENSITIVITY ASSAY AND ITS ASSOCIATION WITH REVERSIBLE MYOCARDIAL ISCHAEMIA IN PATIENTS WITH AND WITHOUT LV SYSTOLIC DYSFUNCTION

Introduction Detectable levels of cardiac troponin-T by high sensitivity assay (hs-TnT) are elevated by both ischaemia and LV systolic dysfunction (LVSD) but it is unknown whether hs-TnT could be a useful biomarker to identify ischaemia either in the presence or the absence of LVSD. Methods 500 consecutive patients undergoing a clinically indicated dipyridamole myocardial perfusion scintigraphy were studied. Those with impaired renal functions and history of atrial fibrillation or valvular disease were excluded. The troponin-T levels were measured in serum using a highly sensitive assay on an automated platform (Elecsys E170, Roche Diagnostics, lower limit of detection 3 ng/l). All scans were interpreted by a trained physician blinded to the biomarker data. Patients were divided into four groups based on reversible ischaemia and stress ejection fraction (EF) on gated SPECT imaging. Results Data were available for 453 patients and 97/453 had a reversible ischaemic defect. hsTnT levels were significantly higher in patients with a reversible ischaemia (Median (IQR) 7.2 (3.3–10.9) vs 4.2 (3.0–7.5) pg/ml p Conclusions Baseline hs-cTnT levels are an independent predictor of reversible myocardial ischaemia and this is still the case in the presence of LVSD.

126: Comparison of gated SPECT ejection fraction measured immediately and more than 40 minutes after stress resting using a fast camera acquisition and Technetium labelled Tetrosformin

The aim of this study is to compare the gated SPECT ejection fraction (EF) measured a few minutes (mn) after stress and more than 40 mn after stress by using Myoview as tracer and a gamma camera with fast acquisition (GE discovery). It is generally accepted that patients without severe ischemia have a post stress ejection fraction equal to the post rest one. It is also accepted that a difference of more than 5% in absolute value between 2 EF is considered as significantly different. In our study 111 patients, mean age 59,7 years, without known coronary artery disease (CAD), had first a 4 mn fast camera acquisition. The mean delay between myoview injection and beginning of SPECT imaging was 3,83 mn+/− 2,98 with a mean cardiac rate of 86,86±26 bpm. The secon acquisition was done after 42,89 mn+/− 19 mn and the mean cardiac rate was 74,34+/− 22 bpm. Mean difference in the delay is 39 mn (Max 64, Min 22). The average value of the immediate EF (computed from the first scan) was 71,55 +/−17,’4% and the average value of the delayed EF (computed from the second scan) was 64,68+/− 16,8%. The resulting mean difference is 6,86+/−14 which is significant. Mean difference between the end diatolic volume is −5,16 and −7,26 for the end systolic volume. Myocardial perfusion was normal in all the patients. The EF value measured on a scan done just after the stress test is significantly higher than the one mesured after a delay of about 40 mn This is an interesting result as a lower than expected ejection fraction value after stress compared to the rest one may be an argument for a severe CAD.

Similar survival 15 years after coronary artery surgery irrespective of left main stem stenosis

Objectives. To evaluate 15-year survival after coronary artery bypass grafting (CABG) in relation to grade left main stenosis (LMS) and right coronary artery (RCA) obstruction. Design. Coronary angiographic findings were prospectively collected in 977 patients who had CABG for stable angina during 1994–1995 and were included in the Swedish Coronary Revascularization – Swedish Council of Technology Assessment study. Results. Significant LMS was present in one fifth of the patients and significant RCA obstruction was found in 61% of those with LMS and in 68% of patients without LMS. The patients were categorized as no LMS (Group I), LMS without RCA obstruction (Group II) or significant LMS with significant right coronary artery (RCA) obstruction (Group III). Early mortality did not differ in the three groups and was 1.2, 1.2% and 0.8% in group I, II and III, respectively. Corresponding survival at 15 years was similar 51%, 47% and 47%, respectively. In multivariable analysis older age, smoking, severe angina, positive stress test, hypertension, diabetes mellitus and ejection fraction < 50% were risk factors for death at 15 years. Conclusions. Death 15 years after CABG correlated to clinical variables but was not predicted from presence of LMS with or without significant associated RCA obstruction.

Ejection Fraction Change and Coronary Artery Disease Severity: A Vasodilator Contrast Stress-Echocardiography Study

An important goal of noninvasive stress testing is the identification of patients with left main coronary artery or three-vessel disease, because coronary artery disease extension and severity are major prognostic factors in ischemic heart disease. Wall motion abnormalities during vasodilator stress echocardiography become apparent in more than one coronary territory only in a small number of patients with multivessel disease. The aim of this study was to assess the value of change in left ventricular ejection fraction change (ΔLVEF) to identify patients with multivessel obstructive coronary artery disease during dipyridamole stress echocardiography. All dipyridamole stress echocardiographic studies performed at the authors' institution from October 2007 through March 2010 were retrospectively reviewed, and 150 patients who underwent coronary angiography within the next 60 days were selected. Left ventricular end-diastolic volume and end-systolic volume were measured at baseline and at the end of high-dose dipyridamole; ΔLVEF was calculated as stress ejection fraction minus rest ejection fraction. Patients were divided into four groups (controls and patients with single-vessel, two-vessel, and three-vessel disease) on the basis of coronary angiographic results. The mean LVEF increased significantly from rest to peak stress in all groups except the three-vessel disease group. Mean ΔLVEF was negative in patients with three-vessel or left main coronary artery disease (-2.8 ± 5.1%) and significantly lower compared with all other angiographic groups (10.2 ± 5.1% and 6.2 ± 4.1%, respectively, for single-vessel and two-vessel disease). The negative value of ΔLVEF for three-vessel disease was due mainly to increased end-systolic volume at peak stress. Receiver operating characteristic curves demonstrated excellent accuracy of ΔLVEF compared with change in wall motion score index in identifying patients with multivessel disease, with areas under the curves of 0.96 and 0.62, respectively. ΔLVEF is significantly lower in patients with severe coronary artery disease compared with those with single-vessel or two-vessel disease; reduced ΔLVEF identifies high-risk patients, who are likely to benefit from a more aggressive therapeutic strategy.

025 Very low dose myocardial perfusion imaging with 1 mSv using cadmium-zinc-telluride (CZT) cameras and Tc99m-sestamibi

Background: Myocardial perfusion imaging is an essential tool for management of coronary artery disease but leads to relative high radiation exposure (average: 20 mSv, Berrington de Gonzalez, Circulation 2010) and contributes up to 20% of the estimated annual collective radiation dose. We previously published validation of new CZT cardiac cameras, improvement of diagnosis performances and reduction of dosimetry lower than 10 mSv with thallium (JESFC 2010). Objectives: We used new cardiac CZT cameras to decrease to only 1 mSv the effective dose with technetium agents. Methods: We prospectively studied 100 consecutive patients without previously known coronary artery disease referred for diagnostic stress myocardial perfusion imaging. We injected at stress a low dose of Tc99m-sestaMIBI (1.75 MBq/kg), performed immediate stress myocardial scan in 10 mn with a CZT camera GE DNM 530c. We practiced rest myocardial scan 4 hours later only when stress images were abnormal, with injection of a treble activity. Results: Patients were 59 males and 41 females.There weight was 78±15 kg. They received at stress 135±30 MBq of Tc99m-sestaMIBI. Total and myocardial acquired counts were 1092±308 kcts and 317±91 kcts. Quality of scan was excellent in 82 cases and acceptable in other cases. The results were normal in 90 cases and abnormal in 10 cases (3 artifacts,4 ischemia and 3 unknown myocardial infarction scar). Normal stress ejection fraction was 68± 7%, end-diastolic and end-systolic volumes were 72±27 and 23±11 ml. The effective dose at stress was 0.79±0.08 mSv for men and 1.02±0.07 mSv for women. The rest activity (average 430 MBq) leads to an additional dose of 3.02 mSv for men and 3.89 mSv for women. Conclusions: With reduced activities of Tc99m-sestaMIBI, CZT cameras give high quality imaging. It leads to a decrease of equivocal results and a low ratio of patients needing an additional rest scan. The effective dose is thus very low, less or equal to 1 mSv in most cases.

Reduced End-Systolic Pressure-Volume Ratio Response to Exercise

Background— Limitations in the predictive value of negative exercise echocardiography in type 2 diabetes mellitus has been linked to a reduced end-systolic pressure-volume response (ESPVR). We sought whether abnormal ESPVR reflected subclinical diabetic heart disease by examining the association between the ESPVR and markers of myocardial dysfunction and to establish if the change (Δ) or peak systolic blood pressure/end-systolic left ventricular volume ratio (SP/ESV) is a better marker of contractile reserve in type 2 diabetes mellitus. Methods and Results— Resting and exercise echocardiography was performed in 167 apparently healthy patients with type 2 diabetes mellitus (97 men; age, 55±10 years) without ischemia, other cardiac disease, or noncardiac complications of diabetes. Standard echocardiographic and color tissue Doppler measures (early diastolic tissue velocity, strain, and strain rate) were acquired at baseline and peak stress in apical long-axis views. Calibrated integrated backscatter was calculated from a resting parasternal long-axis view. ΔSP/ESV was calculated as [(peak stress SP/ESV)−(rest SP/ESV)]. The 83 subjects who demonstrated a ΔSP/ESV ≤12 mm Hg/mL/m 2 after exercise were older and had lower peak heart rate, resting diastolic and stress systolic tissue velocity, stress ejection fraction, and exercise capacity than the remainder. There was no significant association between ΔSP/ESV and metabolic derangement or echocardiographic measures of deformation or backscatter. Change in Sm and stress ejection fraction were independent correlates of ΔSP/ESV. Conclusions— ΔSP/ESV ratio is associated with established features of subclinical diabetic heart disease as well as determinants of contractile reserve (peak hemodynamic response and stress systolic function). Peak ESPVR is poorly associated with markers of myocardial dysfunction.