Post-stress Left Ventricular Ejection Fraction Research Articles

Evaluation of Perfusion and Function in Cardiac Radionuclide Imaging in Cases of Heart Failure with Mid-Range Ejection Fraction

Objective: Heart failure with mid-range ejection fraction (HFmrEF) poses a significant clinical challenge due to its diverse etiology and variable prognosis. Patients with HFmrEF exhibit an intermediate level of left ventricular dysfunction, making their management and prognosis less well-defined compared to those with heart failure with reduced ejection fraction (HFrEF) or preserved ejection fraction (HFpEF). Coronary artery disease (CAD) is a common underlying cause of HFmrEF and can further exacerbate myocardial dysfunction under stress conditions. In this study, we aimed to evaluate the change in left ventricular ejection fraction with stress in the presence of coronary artery disease in cases of heart failure with mid-range ejection fraction. Material and Methods: In this retrospective study, we included 507 patients diagnosed with coronary artery disease and an left ventricular ejection fraction (LVEF) of 41-49% measured by echocardiography. All patients underwent a treadmill exercise test using the Bruce protocol, with progressively increasing speed and incline. Myocardial perfusion was assessed using stress gated myocardial perfusion scintigraphy (MPS), and fixed and reversible defects were identified in cases of coronary artery disease. Cardiac scintigraphic images were acquired from the right anterior oblique to the left posterior oblique. We calculated post-stress LVEF and the percentage decrease in LVEF to evaluate cardiac function. Results: Resting LVEF was measured as 46 (43-50), while post-stress LVEF was 35 (25-47) in all patients. Myocardial perfusion was evaluated using stress gated MPS in all patients, with 200 (39.5%) patients showing both fixed and reversible perfusion defects. The rate of decrease in LVEF due to stress was significantly higher in patients with reversible perfusion defects (15.90 (6-30.43) vs. 28.26 (24-43.18), p: 0.0005). Post-stress LVEF was lower in patients with reversible perfusion defects (40 (31-47) vs. 33 (25-38), p: 0.0005). Conclusion: In cases of impaired left ventricular perfusion, quantitative calculations of LVEF may vary, and their reliability may decrease as the ejection fraction decreases under stress conditions. Clinicians should consider this variability in the follow-up of patients with heart failure and mid-range ejection fraction.

Radionuclide Imaging Findings in Iatrogenic Stress in Cases with Reduced Left Ventricular Ejection Fraction

Objective: This study aims to contribute to the existing literature by assisting in the selection of stress protocols for patients with reduced left ventricular ejection fraction (LVEF). We also aim to provide insights into patient follow-up based on changes in post-stress LVEF determined by echocardiography. Methods: Our retrospective study encompassed 487 patients initially diagnosed with coronary artery disease. Left ventricular function was assessed using echocardiography and myocardial perfusion scintigraphy. Among them, 250 patients with LVEF values within normal limits constituted Group-1, while 237 patients with LVEF values below 50% formed Group-2. Exercise stress testing was performed using a treadmill according to the Bruce protocol. For vasodilator stress testing, intravenous adenosine infusion at a rate of 140 μg/kg/min was administered for 6 minutes. Tc-99m-sestamibi was intravenously administered (8-12 mCi) for stress imaging and (24-36 mCi) for rest imaging. Results: The median age of all patients in the study was 64 (52-79) years, with 283 (58.1%) being male. Myocardial perfusion, assessed by myocardial perfusion scintigraphy, revealed a fixed perfusion defect in all patients. Reversible perfusion defects were observed in 172 (35.3%) patients. Among patients with reduced echo-LVEF values, those who underwent exercise stress testing showed significantly lower post-stress EF values compared to those who underwent vasodilator stress testing (35 (25-42) vs. 36 (30-47), p: 0.0005). Post-stress LVEF was notably lower in patients with reversible perfusion defects, indicating a higher rate of LVEF decrease due to stress (p: 0.0005). Conclusion: Left ventricular ejection fraction (LVEF) serves as a valuable metric for assessing left ventricular function. The findings from this study support its utility in guiding the selection of a suitable stress protocol and monitoring patients during iatrogenic cardiac stress applications.

Prognostic value of absent left ventricular ejection fraction reserve with regadenoson SPECT MPI

BackgroundAn absent left ventricular ejection fraction (LVEF) reserve with vasodilator stress with PET cardiac imaging has been shown to provide significant independent and incremental value to the perfusion images for prediction of future cardiovascular adverse events. However, the prognostic value of LVEF reserve has not been well characterized with SPECT myocardial perfusion imaging (MPI). MethodsWe studied 858 consecutive patients with normal and abnormal perfusion pattern with regadenoson SPECT MPI. Change in LVEF was calculated as post-stress LVEF—rest LVEF. Absent LVEF reserve was defined as a drop in LVEF by 5% or more on the post-stress images. The primary outcome was a composite of cardiac death, non-fatal myocardial infarction and late coronary revascularization. ResultsAn absent LVEF reserve was more common in patients with abnormal vs normal MPI (31% vs 19%, P = .001). During a median follow-up of 32 months, the primary outcome was experienced by 31% of the study population. An absent LVEF reserve was not associated with an increased risk of the primary outcome in patients with normal (hazard ratio 1.1, 95% CI .4-2.7, P = .8) or abnormal (.75, .56-1.00, P = .05) MPI. There was no significant correlation between extent of ischemia and post-stress change in LVEF (Pearson r = − .072, P = .07). ConclusionsIn patients undergoing regadenoson SPECT MPI, absent LVEF reserve is not associated with worse cardiac outcomes. Thus, routine reporting of both post-stress and rest LVEF measurements in this setting may not be necessary.

Prognostic value of early left ventricular ejection fraction reserve during regadenoson stress solid-state SPECT-MPI

BackgroundWe hypothesized early post-stress left ventricular ejection fraction reserve (EFR) on solid-state-SPECT is associated with major cardiac adverse events (MACE). Methods151 patients (70 ± 12 years, male 50%) undergoing same-day rest/regadenoson stress 99mTc-sestamibi solid-state SPECT were followed for MACE. Rest imaging was performed in the upright and supine positions. Early stress imaging was started 2 minutes after the regadenoson injection in the supine position and followed by late stress acquisition in the upright position. Total perfusion deficit (TPD) and functional parameters were quantified automatically. EFR, ∆end-diastolic volume (EDV), and end-systolic volume (ESV) were calculated as the difference between stress and rest values in the same position. EFR < 0%, ∆EDV ≥ 5 ml, or ∆ESV ≥ 5 ml was defined as abnormal. ResultsDuring the follow-up (mean 3.2 years), 28 MACE occurred (19%). In Kaplan–Meier analysis, there was a significantly decreased event-free survival in patients with early EFR < 0% (P = 0.004). Similarly, there was a decreased event-free survival in patients with ∆ESV ≥ 5 ml at early stress (P = 0.003). However, EFR, ∆EDV, and ∆ESV at late stress were not associated with MACE-free survival. Cox proportional hazards model adjusting for clinical information and stress TPD demonstrated that EFR, ∆EDV, and ∆ESV at early stress were significantly associated with MACE (P < 0.05 for all). ConclusionsReduced early post-stress EFR on vasodilator stress solid-state SPECT is associated with MACE.

Combination of myocardial perfusion imaging, left ventricle function parameters and coronary artery calcium score in risk evaluation in patients with diabetes mellitus.

Myocardial perfusion imaging (MPI) can be challenging in some cases of multi vessel involvement. Our aim was to examine specific group of patients with diabetes mellitus (DM), who did not have significant reversible ischaemia diagnosed on perfusion study itself, and asses additional value of functional parameters obtained from gated acquisition and added information from coronary artery calcium score (CACS). One hundred and seventy eight patients with a history of DM, with summed difference score (SDS)≤1, were included in the study. All patients underwent gated acquisition with recording of functional parameters and CACS evaluation. During the follow-up, cardiac events (CE) were recorded. During the median follow-up of 20.3 months there were 23 CE encountered. Optimal cut-off value for CACS to predict CE was found at 1427, higher values were significantly related to CE (P<0.001). Low stress left ventricular ejection fraction (LVEF) <45% and induced stress LVEF drop for 5% were also more frequent in CE group (P=0.001, P=0.008). Multivariable Cox analysis revealed low stress LVEF (P=0.001, HR=4.48, 95%CI 1.79-11.22), stress induced LVEF drop (P=0.017, HR 3.13, 95%CI 1.22-8.01) and high CACS (P<0.001, HR 10.52, 95%CI 4.32-25.63) as significant predictors of CE. Low stress LVEF under 45%, post-stress LVEF drop for more than 5% and CACS more than or equal to 1427 are significant predictors of CE in patients with DM, who did not have reversible ischemia detected on MPI single photon emission computed tomography (SPECT).

Stress myocardial perfusion imaging in patients presenting with syncope: Comparison of PET vs. SPECT

BackgroundThe role of myocardial perfusion imaging (MPI) in patients with suspected coronary artery disease (CAD) presenting with syncope is controversial. We aimed to determine diagnostic yield of MPI for evaluation of syncope in patients without known CAD, as a function of pre-test patient risk and test modality (PET vs SPECT). MethodsBetween 1/2010 and 12/2016, 1324 consecutive patients presenting with syncope without known CAD underwent MPI with PET (n = 640) or SPECT (n = 684). Rates of abnormal MPI (summed difference score (SDS) > 2 or left ventricular ejection fraction (LVEF) reserve ≤ 0 for PET and SDS > 2 or post-stress LVEF ≤ 45% for SPECT) were determined among patients stratified by pre-test risk. In patients who were referred for coronary angiography, diagnostic yield of obstructive CAD was calculated in the overall cohort as well as in a propensity-matched cohort compared to patients without syncope. ResultsAbnormal MPI was noted in 36.5% (201/551) of patients who had PET compared with 13.0% (87/671) who had SPECT (P < 0.001), which is largely related to higher comorbidity burden and greater pre-test CAD risk in the PET population. Among patients who had an abnormal MPI, 8.5% (47/551) with PET and 0.7% (5/671) with SPECT were found to have obstructive CAD if referred for coronary angiography. Patients at intermediate-high pre-test risk had a higher proportion of abnormal MPIs and obstructive CAD as compared to those at low risk in both the PET and SPECT cohorts. The rate of abnormal testing and diagnostic yield of PET MPI was similar and proportionate to pre-test likelihood among matched patients with and without syncope. ConclusionsAmong patients referred for PET MPI with syncope at an intermediate-high pre-test CAD risk, 1 in 3 had an abnormal MPI and 1 in 10 had obstructive CAD. The value of MPI was related to pre-test risk as opposed to the presence of syncope, and MPI testing with PET or SPECT in the low-risk population was low value.

The prognostic value of regadenoson SPECT myocardial perfusion imaging: The largest cohort to date

BackgroundData on the prognostic value of regadenoson SPECT myocardial perfusion imaging (MPI) is limited and based on small cohorts. Methods and ResultsWe conducted a single-center, retrospective cohort study of 10,275 consecutive patients who underwent regadenoson SPECT-MPI. Among the study subjects, 28.7% had abnormal MPI and 25.5% had myocardial ischemia. Patients were followed for a mean of 2.4 ± 2.2 years for major adverse cardiac events (MACE), defined as cardiac death or myocardial infarction. There was a significant stepwise increase in MACE with an increasing burden of perfusion abnormality (P < .001) and myocardial ischemia (P < .001). Abnormal MPI (adjusted HR 1.52; 95% CI 1.21 to 1.91) and myocardial ischemia (adjusted HR 1.53; 95% CI 1.25 to 1.89) were associated with MACE, independent of and incremental to clinical covariates and left ventricular ejection fraction (LVEF). Moreover, post-stress LVEF, LVEF reserve, and left ventricular end-diastolic volume added significant prognostic information. Transient ischemic dilation ≥ 1.31 did not provide incremental prognostic value (adjusted HR 1.02; P = .906). ConclusionIn the largest cohort to date, we demonstrated that the presence and severity of perfusion abnormality and myocardial ischemia on regadenoson stress SPECT-MPI are associated with an independent increase in MACE.

Left ventricular mechanical dyssynchrony in patients with chest pain and normal epicardial coronary arteries

BackgroundTo detect ischemia in patients with angina and normal coronaries frequently represents a complex diagnosis. MethodsTo investigate whether left ventricular mechanical dyssynchrony by phase analysis contributes in the evaluation of patients with chest pain and normal coronaries, gated-SPECT myocardial perfusion imaging (MPI) at rest and 30 minutes post-stress was performed in 218 patients with normal epicardial coronaries, who were divided into two groups: those with summed difference score (SDS) ≥ 4 (54 patients, Group 1), and those with SDS < 4 (164 patients, Group 2). Intraventricular synchronism-phase standard deviation (PSD) and histogram bandwidth (HBW)—was evaluated by phase analysis. ResultsWomen were significantly more frequent in Group 2 (those without ischemia in SPECT MPI): 113 (69%) vs 25 (46%), P = .00001. In males, left ventricular ejection fraction (LVEF) and ventricular volumes were not significantly different between patients with or without ischemia. However, ischemic females showed significantly higher ventricular volumes, minor post-stress LVEF and more negative delta LVEF (− 3.9 vs 0.34, P = .0008) than the non-ischemic ones. There was a significant post-stress increase of PSD and HBW among males, although not among females. According to SSS (≥ 4, with ischemia/necrosis; < 4, without ischemia/necrosis), post-stress PSD and HBW significantly increase both in male and female, and PSD and HBW were significantly higher in females with SSS ≥ 4 compared to those with SSS < 4 (PSD rest: 19.04° vs 11.72°, P < .0001; HBW rest: 58.85° vs 38.21°, P < .0001). PSD and HBW were also higher among males with SSS ≥ 4 compared to those with SSS < 4, although not significantly. ConclusionHigher ventricular volumes in females and dyssynchrony are associated with inducible ischemia in MPI in patients with chest pain and normal coronaries. Stress-induced ischemia increases degree of dyssynchrony.

Prognostic significance of post-stress reduction in left ventricular ejection fraction with adenosine stress in Jordanian patients with normal myocardial perfusion

BackgroundThe significance of post-stress reduction in left ventricular ejection fraction (LVEF) in patients with normal perfusion on adenosine stress/rest imaging remains controversial. MethodsConsecutive patients who underwent 2-day adenosine gated stress/rest 99mTc-sestamibi imaging and had normal perfusion were analyzed. LVEF was quantified at rest and 1 hour post-adenosine. Patients were followed up for hard (cardiac death or nonfatal MI) and soft (coronary revascularization or congestive heart failure) cardiac events for 24.1 ± 11.0 months. ResultsOf 560 patients included in the study, 135 (24.1%) had a post-stress reduction in LVEF of ≥ 5%. Rest LVEF (P < 0.001), known history of CAD (P = 0.01) and transient ischemic dilatation ratio (P = 0.02) were independent predictors of LVEF reduction. Event-free survivals were similar in patients with and without ≥ 5% LVEF reduction (P = 0.8). The unadjusted hazard ratio (95% CI) for cardiac events for ≥ 5% LVEF reduction was 1.09 (0.55-2.15), P = 0.81, while the hazard ratio adjusted for known history of CAD, smoking, post-stress LVEF and peak heart rate was 0.87 (0.44-1.75), P = 0.71. ConclusionsSignificant post-adenosine reduction in LVEF occurs in about one-fourth of patients with normal perfusion but does not confer adverse prognosis compared with patients without such reduction.

Étude et comparaison de la valeur pronostique de différents scores clinique, coronarographique et scintigraphique chez le patient coronarien stable après un syndrome coronarien aigu

IntroductionTo date, there is no consensus regarding the follow-up of asymptomatic coronary patients with an intermediate risk of events. Indeed, most of cardiovascular events (CVE) occur in asymptomatic patients, hence the clinician's interest in establishing risk stratification scores. In asymptomatic patient, the risk assessment after acute coronary syndrome (ACS) can currently be based on 3 types of score: clinical with, for example, the REACH score; angiographic with the residual SYNTAX score; imaging with different scintigraphic scores. These scores differ widely in terms of evaluation criteria and period of analysis. The aim of our study was therefore, in stable and asymptomatic coronary patients after ACS, to compare these different predictive scores; to establish that the combination of these scores makes it possible to optimize the risk assessment during the follow-up. MethodsOur retrospective study included 236 revascularized patients after ACS. Three different risk scores were collected: 1) the residual SYNTAX score, calculated at the time of revascularization; 2) the scintigraphic risk score described by Sharir et al., performed 3 to 12 months after the event and taking into account the extent of ischemia (SDS) and the poststress left ventricular ejection fraction (LVEF). Patients with LVEF <50% and/or moderate to severe ischemic disease (SDS≥2) were considered with an intermediate or high scintigraphic risk; 3) the REACH clinical score calculated on the day of the scintigraphic examination. After the myocardial scintigraphic exam, patients had a 1-year follow-up and CVE were recorded. Continuous data were analyzed either by Student's t-test or non-parametric Mann-Whitney test. The dichotomous data were compared either by the χ2 test or by Fisher's exact test. ResultsForty-eight patients (20.1%) had a CVE during the 1-year follow-up. Thirty patients (13.8%) had a high residual SYNTAX score (≥8) without any correlation observed between the residual SYNTAX score and CVE (P=0.359). 148 patients (57.7%) had a high REACH clinical score (≥11) with no significant correlation observed with CVE (P=0.079). Lastly, 34 patients (14.4%) had an intermediate or high scintigraphic score, this imaging score being strongly correlated with a greater number of CVE (P<0.001). Multivariate analysis revealed 3 independent factors associated with CVE: a scintigraphic score> 2 (OR [(95% CI): 5.530 [2.426–12.605] P<0.001); Peripheral Arterial Obstructive Disease (PAOD) (OR [95% CI]: 8.531 [2.540–28.660] P<0.001); diabetes (OR [95% CI]: 2.86 [1.262–6.517] P=0,012). ConclusionThe combination of the scintigraphic score with two clinical factors, such as PAOD and diabetes, provides optimal prognostic value in the evaluation of asymptomatic and stable patients after ACS. Our study therefore highlights the importance of optimizing evaluation strategies in the follow-up of these patients who remain at risk of post-revascularization CVE.

Warranty period of normal stress myocardial perfusion imaging in diabetic patients: A propensity score analysis

BackgroundWe evaluated the relationship between diabetes and temporal characteristics of cardiac risk at long-term follow-up in a propensity score-matched cohort of diabetic and non-diabetic patients with normal stress myocardial perfusion single-photon emission computed tomography (MPS). Methods and ResultsWe studied 828 consecutive patients with suspected or known coronary artery disease and normal perfusion at stress MPS. To account for differences in baseline characteristics between diabetics and non-diabetics, we created a propensity score-matched cohort considering clinical variables and stress type. After matching, clinical characteristics were comparable in 260 diabetic and 260 non-diabetic patients. All patients were followed for at least 1 year (median 53 months). End-point events were cardiac death or nonfatal myocardial infarction. At Cox analysis, diabetes (hazard ratio 3.9, P < .01) and post-stress left ventricular ejection fraction (LVEF) ≤45% (hazard ratio 4.1, P < .01) were independent predictors of events. At parametric analysis, non-diabetic patients with post-stress LVEF >45% remained at low risk for the entire length of follow-up, while the highest probability of events and the major risk acceleration was observed in patients with diabetes and post-stress LVEF ≤45%. ConclusionsAfter a normal stress MPS, diabetic patients are at higher risk for cardiac events than non-diabetic subjects also after balancing clinical characteristics and stress type by propensity score analysis. The warranty period of a normal stress MPS varies according to diabetic status and post-stress LVEF.

Post-stress left ventricular ejection fraction drop in patients with diabetes: a gated myocardial perfusion imaging study

BackgroundTo evaluate the relevance of stress-induced decrease in left ventricular ejection fraction (LVEF) in patients with type-2 diabetes.MethodsA total of 684 diabetic patients with available rest and post-stress gated myocardial perfusion single-photon emission computed tomography (MPS) data were enrolled. An automated algorithm was used to determine the perfusion scores using a 17-segment model. LVEF drop was considered significant if the post-stress LVEF was ≥5% below the rest value. Follow-up data were available in 587 patients that were followed for the occurrence of cardiac death, nonfatal myocardial infarction, or unstable angina requiring revascularization.ResultsA post-stress LVEF drop ≥5% was observed in 167 (24%) patients. Patients with LVEF drop had higher summed stress score (p < 0.05), summed difference score (p < 0.001), and rest LVEF (p < 0.001) compared to patients without. Conversely, summed rest score, a measure of infarct size, was comparable between the two groups. At multivariable analysis, summed difference score and rest LVEF were independent predictors (both p < 0.001) of post-stress LVEF drop. Myocardial perfusion was abnormal in 106 (63%) patients with post-stress LVEF drop and in 296 (57%) of those without (p = 0.16). The overall event-free survival was lower in patients with post-stress LVEF drop than in those without (log rank χ2 7.7, p < 0.005). After adjusting for clinical data and MPS variables, the hazard ratio for cardiac events for post-stress LVEF drop was 1.52 (p < 0.01).ConclusionsIn diabetic patients stress-induced ischemia is an independent predictor of post-stress LVEF drop; however, a reduction in LVEF is detectable also in patients with normal perfusion. Finally, post-stress LVEF drop increases the risk of subsequent cardiac events in diabetic patients.

Transient Ischemic Dilation in Patients With Diabetes Mellitus

Background— We prospectively evaluated the incremental prognostic value of transient ischemic dilation (TID) in patients with type 2 diabetes mellitus during long-term follow-up and estimated cardiac death and nonfatal myocardial infarction (MI) using traditional approaches of prognostication to more recent methods. Methods and Results— A total of 672 consecutive diabetic patients with available rest and stress gated myocardial perfusion single-photon emission computed tomographic data were enrolled. Stepwise Cox regression analysis was used to estimate cardiac death or nonfatal MI. Risk reclassification was calculated, and an exploratory analysis was performed to evaluate the effect of coronary revascularization on event-free survival. Adding TID to a multivariable model, including age, history of MI, stress type, poststress left ventricular ejection fraction, and stress-induced myocardial ischemia, improved discrimination of cardiac death or nonfatal MI (C statistic, 0.74–0.82; P =0.01; adjusted hazard ratio, 3.6; P &lt;0.0001) and led to a net reclassification improvement of 0.39 (95% confidence interval, 0.14–0.64). Revascularization had a significant effect on event-free survival (adjusted hazard ratio, 0.25; P &lt;0.001), with significant interactions between revascularization and poststress left ventricular ejection fraction, revascularization and stress-induced myocardial ischemia, and revascularization and TID (all P &lt;0.01) Conclusions— TID provides independent and incremental prognostic information for the prediction of cardiac death or nonfatal MI in patients with diabetes mellitus. The addition of TID to a prediction model based on cardiovascular risk factors, left ventricular ejection fraction, and ischemia significantly improves risk discrimination and reclassification for incident cardiac events. The effect of revascularization seems to be influenced by left ventricular systolic function, stress-induced myocardial ischemia, and TID.

ASSA13-05-2 Left Ventricular Functional Changes During Adenosine Stress and Its Relationship with Myocardial Ischemia in Gated SPECT

<h3>Objective</h3> This paper aimed at investigating left ventricular functional changes during adenosine stress and its relationship with myocardial ischemia evaluated with gated SPECT. <h3>Methods</h3> 125 patients suspected or known CAD (coronary artery disease) underwent adenosine stress-rest protocol and gated single photon emission computed tomography (SPECT). Perfusion analysis was performed with a 17-segment model and 5-point scale system. Summed stress score (SSS), summed rest score (SRS) and summed difference score (SDS = SSS-SRS) were calculated. DLVEF, DEDV and DESV were defined by changes in LVEF (left ventricular ejection fraction), ESV (end systolic volume), EDV (end diastolic volume) after stress. <h3>Results</h3> Resting and poststress LVEFs correlated significantly. Patients with irreversible ischemia had lower rest and poststress LVEF than normal perfusion patients (t = 2.235, P = 0.028; t = 2.464, P = 0.016). In patients with reversible myocardial ischemia, poststress LVEFs were significantly depressed (t = 3.146, P = 0.002) which were mainly expressed as ESVs elevated (t = –2.215, P = 0.036), compared with rest. Patients with reversible ischemia showed significant changes in DLVEF and DESV, compared with patients with irreversible ischemia (t = 2.520, P = 0.014; t = –2.412, P = 0.019), or normal perfusion (t = 3.115, P = 0.002; t = –3.517, P = 0.001). <h3>Conclusions</h3> Patients with fix defect had depressed LV functions at rest and after stress, while in patients with stress-induced ischemia, poststress LV functions were impaired, which were not happened in patients with fixed defect or without ischemia. In daily clinical practise, compared with visual myocardial perfusion alone, integration ofLVfunctional message enhanced the diagnostic ability of adenosine stress SPECT in patients with CAD.

Incremental prognostic value of stress myocardial perfusion imaging in asymptomatic diabetic patients

ObjectiveStress myocardial perfusion single-photon emission computed tomography (MPS) variables are robust estimators of prognosis. No data are available on the comparative ability of stress MPS risk markers using varied iterative and risk classification approaches in asymptomatic diabetic patients. We compared analytical approaches to estimate the added value of MPS variables in estimating coronary artery disease (CAD) outcomes in asymptomatic diabetic patients. We also evaluated the temporal characteristics of cardiac risk according to MPS findings. MethodsA total of 436 consecutive asymptomatic diabetic patients who underwent stress-rest gated MPS were prospectively enrolled. Multivariable Cox proportional hazards model was employed to estimate cardiac death and nonfatal myocardial infarction (MI). Risk reclassification was calculated and parametric survival analysis was used to predict time to events. ResultsAt multivariable analysis, post-stress left ventricular ejection fraction (LVEF) and stress MPS ischemia were independent predictors of CAD death or MI (both p < 0.01). The net reclassification improvement by adding MPS results to a model including pre-test CAD likelihood was 0.25 (95% confidence interval 0.06–0.44; p < 0.01). Parametric survival analysis showed the highest probability of CAD death or MI and the major risk acceleration in time in patients with stress MPS ischemia and post-stress LVEF ≤45%. ConclusionIn asymptomatic diabetic patients, analytical approaches that establish the reclassification of events may serve for estimation of improved outcomes for stress MPS. Post-stress LVEF and stress-induced ischemia by gated MPS influence the temporal characteristic of the patient's risk at long-term follow-up.

Myocardial Perfusion Imaging and Cardiac Involvement in the Indeterminate Phase of Chagas Disease

Myocardial perfusion imaging (MPI) has been used in the assessment of chagasic heart disease. To investigate the value of gated-single photon emission computed tomography (gated-SPECT) MPI to detect early cardiac involvement in chagasic patients in the indeterminate phase, who present segmental motion abnormalities detected by tissue Doppler imaging (TDI)-derived strain. Forty individuals (mean age: 25±2 years, 50% males) from an endemic area of Chagas disease and with positive serologic diagnosis, were included. All underwent gated-SPECT two-day (stress-rest) MPI and echocardiography. Thirty individuals (75%) showed a normal scan. In three cases (8%) the MPI was slightly abnormal, and in seven it was equivocal. In all cases with reversible defects, the affected segments were coincident with those with motion abnormalities. A post-stress left ventricular ejection fraction (LVEF) reduction > 5% (ΔLVEF < -5%) was found in 11 out of 40 individuals (28%). Both the phase-derived standard deviation and the histogram bandwidth showed a significant difference between post-stress and rest. In both cases there was a slight dyssynchrony at rest which normalized at post-stress. A stress-rest gated-SPECT is a valid approach to detect early myocardial alterations, as well as intraventricular dyssynchrony in the indeterminate phase of Chagas disease in patients with segmental motion abnormalities previously detected by TDI-derived strain.

Exercise training early after acute myocardial infarction reduces stress-induced hypoperfusion and improves left ventricular function

Exercise training might exert its beneficial effects on myocardial perfusion by inducing coronary vascular adaptations or enhancing collateralization. We evaluated whether long-term exercise-based cardiac rehabilitation started early after ST-elevation acute myocardial infarction (STEMI) improves myocardial perfusion and left ventricular (LV) function. Forty-six patients with recent STEMI and residual inducible hypoperfusion were randomized into two groups: 25 enrolled in a 6-month outpatient exercise-based cardiac rehabilitation programme (group T) and 21 discharged with generic instructions for maintaining physical activity and correct lifestyle (group C). All patients underwent cardiopulmonary exercise test and dipyridamole rest gated myocardial perfusion single photon emission computed tomography within 1week after STEMI and at 6-month follow-up. At follow-up, group T showed an improvement in peak oxygen consumption, oxygen pulse and in the slope of increase in ventilation over carbon dioxide output (all p < 0.01) associated with a reduction of stress-induced hypoperfusion (p < 0.01) and an improvement in resting and post-stress wall motion score indexes (both p < 0.01), resting and post-stress wall thickening score indexes (both p < 0.05) and resting and post-stress LV ejection fraction (both p < 0.05). On the contrary, no changes in cardiopulmonary indexes, myocardial perfusion and LV function parameters were observed in group C at follow-up. Exercise training started early after STEMI reduces stress-induced hypoperfusion and improves LV function and contractility. Exercise-induced changes in myocardial perfusion and function were associated with the absence of unfavourable LV remodelling and with an improvement of cardiovascular functional capacity.

Predictors of post-stress LVEF drop 6 months after reperfused myocardial infarction: a gated myocardial perfusion SPECT study

To identify the predictive factors of myocardial stunning as assessed by the drop in post-stress Left Ventricular Ejection Fraction (LVEF) in patients with a recent history of myocardial infarction (MI). We prospectively included 215 consecutive patients admitted for acute MI who underwent percutaneous coronary intervention with a greater than or equal to grade-3 TIMI flow in the culprit vessel. Six months after discharge, a post-stress/rest 99mTc-sestamibi gated SPECT was performed. The perfusion score was evaluated visually using a 17-segment model. The LVEF drop was considered significant if the post-stress LVEF was ≥ 5% below the rest LVEF (QGS® software). A post-stress LVEF drop was observed in 51 (24%) patients. Patients with an LVEF drop were more likely than patients with a stable post-stress LVEF to have diabetes (22% vs. 10%, p = 0.048), significant ischemia (SDS > 2) (51% vs. 28% p = 0.003) and higher rest LVEF [62% (56-69) vs. 56% (49-63) p < 0.001]. In contrast, summed rest score, related to infarct size, did not differ between the groups. Multivariate logistic regression analysis identified SDS > 2 (OR 3.78, 95% CI 1.8-7.92, p < 0.001), diabetes (OR 3.35, 95% CI 1.33-8.49; p = 0.011) and rest LVEF (OR 1.08, 95% CI 1.04-1.12, p < 0.001) as independent explanatory variables of an LVEF drop. In patients with recent MI and post-procedural grade-3 TIMI flow, ischemia and diabetes were independent predictive factors of myocardial stunning. The higher incidence of reversible perfusion abnormalities validates the model of myocardial stunning in the post-MI period, and excludes the potential involvement of myocardial necrosis.

Association between plasma homocysteine and myocardial SPECT abnormalities in patients referred for suspected myocardial ischaemia

Elevated plasma homocysteine level has emerged as a relatively newly recognised risk factor for coronary artery disease (CAD). However, reduction of plasma homocysteine levels in large prospective studies did not appear to reduce the risk for subsequent cardiac events. In this study, we investigated the association between plasma homocysteine levels and quantitative indices of myocardial perfusion SPECT imaging in patients referred for myocardial ischaemia. Quantitative myocardial perfusion SPECT indices were obtained for 120 patients who were recruited for the study. All patients underwent a two-day rest-stress myocardial perfusion imaging. Plasma venous sampling was done on all patients after an overnight fast. Of the 120 participants (mean age 56 years, 53% males), 33% had elevated plasma homocysteine levels. The plasma homocysteine level was then compared to the results of imaging and other known risk factors. After adjustment for traditional risk factors of coronary artery disease, patients with elevated homocysteine levels had a significantly higher mean summed stress score (SSS) (11.3 vs 6.9, p = 0.02) than patients with a normal homocysteine level. This was true for both single- and multivessel disease. Also, patients with elevated homocysteine levels had a higher stress end-systolic volume (SESV) (137 vs 105 ml, p = 0.03) and lower post-stress left ventricular ejection fraction (SEF) (54 vs 64%, p = 0.02). The patients with elevated plasma homocysteine levels also had a significantly lower mean body mass index (BMI) (26.6 vs 30.6 kg/m(2), p = 0.002). There was a significant relationship between the total number of known risk factors in a patient with CAD and the proportion of patients presenting with elevated plasma homocysteine levels (p = 0.03). Also, the extent of infarct, as measured by the summed rest score (SRS), was more closely correlated with an elevated homocysteine level than with the degree of ischaemia. There was a correlation between plasma homocysteine level and the presence and extent of myocardial perfusion abnormalities in patients with established coronary artery disease, in particular those with multiple risk factors and multi-vessel infarction.

The Relationship Between Quantitative Perfusion and Functional Results and Acquisition Time With Reduced Administered Activity for 99mTc Tetrofosmin Myocardial Gated-SPECT

The aim of this study was to assess the relationship between administered 99mTc tetrofosmin activity in myocardial gated-SPECT and findings of myocardial perfusion and left ventricular ejection fraction (LVEF) as markers of diagnostic outcome. Fifty-two patients with heterogeneous cardiac diseases and a clinical referral for myocardial perfusion imaging were prospectively studied. A separate-day acquisition protocol was adopted with a low fixed activity of 370 MBq, which corresponds to an average reduction of 31% with respect to the median value of 533 MBq usually administered in our laboratory. A standard acquisition with a time/frame of 25 seconds was performed (ST). Immediately after the conclusion of the first acquisition, a second acquisition was performed with a high time/frame of 33 seconds (HT), which corresponds to an increase of 31% with respect to standard time/frame adopted in our laboratory. The order of ST and HT acquisitions was randomized in individual patients. The summed stress scores (SSS), the summed rest scores (SRS), the LVEF, and the end-diastolic volume (EDV) were automatically calculated. The image quality score was significantly higher in HT than in ST. No significant differences were found in SSS, SRS, LVEF, and EDV between HT and ST SPECT. The agreement between HT and ST was 84% (kw=0.88) in the correct classification of stress images. The agreement between HT and ST was 84% (k=0.70) in the detection of ischemia and scar. The limits of agreement between the HT and the ST methods were roughly within ±3 points for SSS and SRS, ±13% for poststress LVEF, and ±18 mL for poststress EDV. Using about half of the activity recommended by the current diagnostic reference levels for separate-day myocardial perfusion imaging, the present study demonstrates that images may be obtained using ST protocol with quantitative results comparable with those from studies performed using the HT protocol, which is equivalent to an administered activity of 530 MBq. The former protocol would allow for a significant reduction of the dose to the patients as well as to the operators. Further studies are needed to confirm that this dose-sparing approach does not hamper sensitivity and specificity for coronary stenoses.