Prognosis of stress-only SPECT myocardial perfusion imaging with prone imaging.

BACKGROUND: Stress-only single-photon emission computed tomography myocardial perfusion imaging (SO SPECT MPI) is associated with similarly benign prognosis as stress-rest SPECT MPI. However, previous studies have used attenuation correction rather than prone imaging to increase the rate of SO studies. OBJECTIVES: To assess the prognosis of SO SPECT MPI performed with prone imaging. METHODS: We performed a retrospective cohort analysis of all patients who underwent a Tc-99m gated SPECT MPI over a 58-month period. RESULTS: Two thousand four hundred and sixty five patients were followed up. Of them, 1114 (45.2%) patients had a SO supine test, 388 (15.7%) underwent a SO supine and prone test, and the remaining 963 (39.1%) patients underwent a full stress-rest SPECT MPI. There was a similar annual mortality rate between the SO supine/prone group (1.3%), the SO supine (1.5%), and the stress-rest (1.5%) group (P = 0.47). Patients in the stress-rest group were significantly more likely to suffer from myocardial infarction (MI) as compared to the other two groups with an annual rate of 0.7% as compared to 0.4% (P = 0.049). CONCLUSIONS: Normal supine-prone SO SPECT MPI is associated with a similarly benign prognosis as stress-rest SPECT MPI. The adjunction of prone imaging to the stress supine significantly increases the rate of SO SPECT MPI.

Yield of left ventricular dyssynchrony by gated SPECT MPI in patients with heart failure prior to implantable cardioverter-defibrillator or cardiac resynchronization therapy with a defibrillator: Characteristics and prediction of cardiac outcome.

BACKGROUND: Mechanical left ventricular dyssynchrony (MLVD) might contribute in the therapeutic decision-making in patients with heart failure (HF) prior to cardiac resynchronization therapy (CRT). Our aim was to assess MLVD in patients with HF prior to implantable cardioverter-defibrillator (ICD) compared to patients with CRT-D. METHODS: In a prospective study, patients with LVEF ≤ 35% who were scheduled for ICD or CRT-D, underwent gated SPECT myocardial perfusion imaging with technetium 99m sestamibi within 3 months prior procedure. MLVD was measured by phase analysis. RESULTS: The study cohort consisted of 143 patients, 71 with ICD and 72 with CRT-D. Age 68.3 ± 11 and LVEF 24 ± 6%. Phase standard deviation (SD) was 62.5 ± 18 and 59.7 ± 20 (P = NS), respectively. During follow-up of 23.7 ± 12.1 months, there were 10 vs 14 cardiac death in ICD and CRT-D, respectively (P = NS), hospitalization for HF, in 34 vs 53 (P < .001). In multivariate analysis, Phase SD was the independent predictor for cardiac death [HR 2.66 (95% CI 1.046-6.768), P = .04]. Kaplan-Meier curves of phase SD of 60° significantly identified ICD patients with and without cardiac deaths and hospitalization for HF exacerbation. CONCLUSIONS: MLVD by phase SD can identify patients with cardiac events and predict cardiac death in patients treated with ICD.

Prognostic value of left ventricular dyssynchrony by myocardial perfusion-gated SPECT in patients with normal and abnormal left ventricular functions.

BACKGROUND: Left ventricular (LV) dyssynchrony by phase analysis has been studied by myocardial perfusion imaging (MPI)-gated SPECT in patients with LV dysfunction in various clinical settings. We aimed to investigate the routine use of phase analysis with gated SPECT for predicting cardiac outcome. METHODS: Patients referred to a tertiary medical center in 2010-2011 prospectively underwent a gated SPECT and phase analysis, and follow-up for cardiac events. The values of clinical variables, MPI, LV function, and LV dyssynchrony in predicting cardiac events were tested by univariate and multivariate analyses. RESULTS: The study group included 787 patients (66.5 ± 11 years, 81% men) followed for a mean duration of 18.3 ± 6.2 months. There were 45 (6%) cardiac events defined as composite endpoint; cardiac death occurred in 26 patients, and the rest had new-onset or worsening heart failure and life-threatening arrhythmias. In multivariate analysis, it was shown that NYHA class, diabetes mellitus, and LVEF <50% were the independent predictors for composite endpoint. However, the independent predictors for cardiac mortality were NYHA class (for each increment in class) and phase standard deviation (SD) (for each 10° increment). CONCLUSION: Gated SPECT with phase analysis for the assessment of LV dyssynchrony can successfully predict cardiac death together with NYHA class, in patients with LV dysfunction.

Association of Helicobacter pylori with coronary artery disease and myocardial infarction assessed by myocardial perfusion imaging.

BACKGROUND: The relationship between Helicobacter pylori infection and coronary artery disease (CAD) has as yet not been fully examined. The myocardial perfusion imaging (MPI) stress test has proven its efficacy as an integral part of diagnosing CAD. OBJECTIVES: To investigate the association between CAD and H. pylori infection using MPI. METHODS: This prospective study evaluated CAD positivity among consecutive patients referred to a tertiary medical center for a stress/rest MPI. All patients were tested for serum anti-H. pylori and CagA protein immunoglobulin G antibodies. The CAD positivity group included patients with ischemia and/or myocardial infarction (MA) on a stress MPI, coronary artery bypass graft surgery (CABG), or percutaneous coronary interventions (PCI). CAD-negative subjects were defined as participants with a normal MPI, no pathological Q waves in resting ECG tracing, and no history of CAD. Both groups were compared for H. pylori and CagA seropositivity. Patients' demographic data, risk factors for CAD, and childhood socioeconomic status were recorded. RESULTS: The study group consisted of 300 consecutive patients, 170 men and 130 women; 64% (110/173) CAD-positive patients and 47% (60/127) CAD-negative participants were found seropositive for H. pylori infection (P = 0.005). In the adjusted analysis, H. pylori infection was found to be associated with CAD positivity (odds ratio 1.83, 95% confidence interval 1.06-3.17, P = 0.031), and MI (fixed perfusion defects on MPI) (OR 3.36, 95% CI 1.44-7.84, P = 0.005). No association was noted with CagA positivity. CONCLUSIONS: In patients undergoing a stress MPI, serum anti-H. pylori antibodies positivity was found to be associated with CAD, independent of traditional cardiovascular risk factors.

Angiographic correlation of myocardial perfusion imaging with half the radiation dose using ordered-subset expectation maximization with resolution recovery software.

BACKGROUND: We previously described the feasibility of performing myocardial perfusion imaging (MPI) with half the technetium (Tc-99m) activity using ordered-subset expectation maximization with resolution recovery (OSEM-RR) processing. This study sought to assess the accuracy of this technique by correlating the findings with coronary angiography. METHODS: Of 290 patients who underwent MPI-gated SPECT using a half dose of Tc-99m sestamibi and OSEM-RR software in 2010-2012 at a tertiary medical center, 62 were referred for invasive coronary angiography within 90 days and formed the study group. Ischemia was defined as a summed difference score (SDS) of >3 on the MPI scan. Luminal stenosis of ≥70% on invasive coronary angiography served as the reference. RESULTS: Mean Tc-99m activity per study was 23.9 ± 11.5 mCi and mean effective radiation dose was 7.2 ± 3.4 mSv. MPI revealed no abnormalities in 10 patients (16.2%), myocardial infarction only in 8 patients (12.9%), and ischemia in 44 patients (71.1%). Overall sensitivity, specificity, and positive and negative predictive values for MPI compared to invasive angiography were 89.1%, 75.0%, 91.1%, and 70.5%, respectively. CONCLUSIONS: MPI SPECT performed with a half dose of Tc-99m and OSEM-RR image processing correlates well with invasive angiography. (J Nucl Cardiol 2013).

Feasibility of myocardial perfusion imaging with half the radiation dose in obese patients using ordered-subset expectation maximization with resolution recovery software.

BACKGROUND: We previously described the feasibility of myocardial perfusion imaging (MPI) with nearly half the radiation dose using ordered-subset expectation maximization with resolution recovery (OSEM-RR) processing. This study sought to determine if the findings can be expanded to obese patients. METHODS: Fifty obese patients (>100 kg) referred for MPI underwent stress-rest or rest-stress studies with a half dose of Tc-99m sestamibi in a 1-day protocol using OSEM-RR processing. Image quality and clinical results were compared with matched patients (by age, sex, weight, presence/probability of coronary artery disease) evaluated with standard "full-dose" Tc-99m sestamibi, mostly in a 2-day protocol. Dose activities were adjusted individually by weight. RESULTS: Mean Tc-99m activity was 33.4 ± 13.9 mCi in the half-dose group and 60 ± 10 mCi in the full-dose group (P < .0001). Respective mean effective doses per study were 10 ± 4 and 18 ± 3 mSv (P < .0001). Overall image quality was good-to-excellent in 94% of the half-dose group and 80% of the full-dose group (P < .045). There was no between-group difference in rate or size of ischemia or infarction, except for stress left ventricular ejection fraction. CONCLUSIONS: MPI with half the radiation dose is feasible in obese patients. Image quality is better than for full-dose MPI, and the procedure can be performed in 1 day.

Yield of a novel ultra-low-dose computed tomography device mounted on a dedicated cardiac SPECT system in improving the accuracy of myocardial perfusion imaging and the detection of chest abnormalities.

BACKGROUND: To examine the yield of an ultra-low-dose computed tomography (CT) transmission module for attenuation-correction (AC) on a dedicated cardiac camera in evaluation of SPECT-myocardial perfusion imaging (MPI) in the diagnosis of CAD and for additional chest abnormalities. METHODS: The study group included 150 patients with known or suspected CAD referred for technetium sestamibi SPECT MPI. CT transmission scanning (effective radiation 0.17 mSv) was performed after each gated SPECT scan. AC and non-corrected (NC) SPECT scans were evaluated on a 5-point scale using a 17-segment model, and the sum stress score (SSS) and sum rest score (SRS) were calculated for each condition. Overall image quality, sensitivity and normalcy rate (51 patients) and processing of 28 CT slices were screened for chest findings. RESULTS: CT-based AC significantly improved image quality (P = .01). Mean SSS was 3.8 ± 5.8 with AC and 6.1 ± 7.1 with NC (P < .001); the respective SRS values were 2.6 ± 6.3 and 3.9 ± 7.7 (P < .001). The sensitivity of detecting ≥70% stenosis was 71% and 86% (P = NS) and the normalcy rate was 30% and 89% (P < .0001) in NC and AC SPECT MPI, respectively. Chest CT: lung abnormalities in 31%, aortic calcifications in 27%, and hiatus hernia in 5%. CONCLUSIONS: Ultra-low-dose CT for AC of SPECT-MPI improves image quality, diagnostic accuracy and suggests detection of chest findings.

Feasibility of myocardial perfusion imaging with half the radiation dose using ordered-subset expectation maximization with resolution recovery software.

OBJECTIVE: This study sought to assess the feasibility of performing myocardial perfusion imaging (MPI) with half the technetium activity using ordered-subset expectation maximization with resolution recovery (OSEM-RR), an iterative reconstruction software developed to improve count statistics and acquisition time. METHODS: Two hundred eighteen patients referred for MPI were randomly allocated to undergo stress-rest or rest-stress protocols with standard full-dose (FD) injections of technetium (Tc)-99m sestamibi or half-dose (HD) injections and OSEM-RR processing. Dose activities were adjusted individually by weight. The groups were compared for image quality and clinical results. RESULTS: The groups were similar for mean patient age, weight, and body mass index, sex distribution, pre-test probability of CAD and CAD prevalence. Mean Tc-99m activities for the low-dose and high-dose stages were as follows: FD group: 429 ± 85 MBq and 1132 ± 200 MBq; HD group: 263 ± 129 MBq and 629 ± 85 MBq (P < .0001 for both). Mean effective dose per study was 13.6 ± 1.4 mSv in the FD group and 7.7 ± 1.0 mSv in the HD group (P < .001). Over all image quality was good-to-excellent in 98% and 95% of the groups, respectively. However, when we analyzed the low-dose stage separately, image quality was slightly worse in the HD than the FD, though still within the good-to excellent range. CONCLUSIONS: MPI with nearly half the radiation dose is feasible with good image quality.

Modalities to assess myocardial viability in the modern cardiology era.

Detection of viable myocardium in patients with left ventricular dysfunction has become an increasingly important guide to prognosis and treatment. This article reviews the current status and future potential for the application of modalities to assess myocardial viability. Imaging and other techniques that are reviewed are myocardial perfusion imaging by single-photon-emission computed tomography, positron-emission tomography, echocardiography, cardiac magnetic resonance technology, computed tomography and catheter-based endocardial mapping.

Prognostic impact of sex on clinical outcomes following emergent coronary angioplasty in acute myocardial infarction.

BACKGROUND: Several studies have shown that women had greater risk for adverse clinical outcomes following coronary angioplasty. We aimed to assess the impact of sex on clinical results following emergent coronary angioplasty in acute myocardial infarction. METHODS: We used our database of patients treated for acute myocardial infarction using emergent coronary angioplasty between January 2001 and December 2003. Procedural and angiographic results and clinical outcomes up to 6 months were collected and adjudicated for major cardiac adverse events. The outcome of 352 patients with acute myocardial infarction (71 women, 281 men, no cardiogenic shock) undergoing emergent angioplasty was analyzed and compared according to sex. RESULTS: Acute myocardial infarction occurred at an older age among women who tended to suffer more from diabetes mellitus and hypertension. In addition, on average, women had smaller culprit vessel diameters than men. The immediate post-procedural data were notable for higher frequency of 'no/slow re-flow' angiographic phenomenon in women than in men (10.5 vs. 3.4%, P=0.04). In-hospital and 30-day mortality was three times higher in women than men (women vs. men: in hospital 7 vs. 2.1%, P=0.05; 30 days 9.9 vs. 3.2%, P=0.02). At 6 months, major adverse cardiac events rate was 28 vs. 15% among women vs. men (P=0.01). Multivariate analysis showed a strong trend towards increased mortality at 30 days among women undergoing acute myocardial infarction angioplasty although it was not significantly or independently related to increased mortality (odds ratio=3.1; confidence intervals=0.8-12.5; P=0.11). CONCLUSION: Our results indicate a trend towards higher early mortality among female patients sustaining acute myocardial infarction and treated using emergent percutaneous coronary intervention that was probably because of increased age and worse coronary flow restoration results among women compared with men.

Variations in lymphocyte activation during exercise testing in patients with coronary artery disease.

BACKGROUND: Several studies have shown that strenuous exercise induces changes in the immune system. Soluble interleukin-2 receptor (sIL-2R) is a marker of immune system activation and is known to increase in association with cardiac disease. The aim of the present study was to assess sIL-2R levels in patients with coronary artery disease (CAD) in conjunction with exercise testing. METHODS: Blood levels of sIL-2R were determined in 10 healthy control individuals and 21 patients with CAD before exercising, at maximal exercise testing (Bruce) and at 0.5 h and 3-4 h after exercise (T1-T4). The study group had stable angina and normal or near-normal left ventricular function. Patients at risk of abnormal cytokine levels were excluded. RESULTS: The patients were divided into two groups: those with mild to moderate ischemia (according to a thallium scan) (n = 14, group 1a) and those with severe exercise-induced ischemia (n = 7, group 1b). The prevalence of anginal pain at exercise and mean ST depression were similar in both groups, however, signs of left ventricular dysfunction during exercise were significantly more frequent in group 1b. Mean sIL-2R levels (units per ml) showed no significant difference between group 1a and the control group at all time points (503 +/- 122, 518 +/- 140, 489 +/- 164, 461 +/- 131 mu/ml compared with 505 +/- 135, 509 +/- 112, 469 +/- 126, 416 +/- 103 mu/ml, respectively, P = NS), while a significant increase in group 1b compared with the control group was found at 0.5-h after exercise (T3) (1147 +/- 510 mu/ml, P = 0.03). DISCUSSION: This study demonstrated immunological involvement in some patients with severe exercise-induced ischemia shortly after exercise, suggesting an association with heart failure.

Additive value of low-dose dobutamine to technetium-99m sestamibi-gated single-photon emission computed tomography for prediction of wall motion improvement in patients undergoing coronary artery bypass graft.

BACKGROUND: The two most useful methods for myocardial viability assessment are perfusion imaging and dobutamine echocardiography. HYPOTHESIS: The present study investigated the additive value of a new method, dobutamine technetium 99m (99mTc)-sestamibi-gated single-photon emission computed tomography (SPECT), which combines these two modalities, to the prediction of wall motion improvement after revascularization. METHODS: Fifty-five consecutive patients with ischemic cardiomyopathy, who were referred for viability evaluation, underwent resting and dobutamine (dose, 5-10 microkg/kg/min) gated SPECT with 99mTc-sestamibi. Of these patients, 36 underwent coronary artery bypass graft (CABG) within 1 month of the study and 32 had repeat resting gated SPECT within 1 year. Global and regional wall motion, wall thickness, and perfusion were simultaneously analyzed at rest and after dobutamine using the 20-segment model; the sestamibi uptake and wall motion response to dobutamine of each segment were rated quantitatively. Based on these findings, the segments were categorized as normal, viable, or nonviable. The predictive values for wall motion improvement were assessed by perfusion, using cutoffs of 50 and 60% of sestamibi uptake, and thereafter by the addition of dobutamine response in the segments that were rated nonviable. RESULTS: Of the 1,080 myocardial segments studied, 906 (84%) had abnormal wall motion and were analyzed for viability. Concordance between perfusion and wall motion response to dobutamine was 60% with the 50% cutoff of sestamibi uptake, and increased to 65% with the 60% sestamibi cutoff (p < 0.04). The respective predictive values of wall motion improvement using the 50 and 60% cutoff points were as follows: sensitivity 93 and 70%, respectively, (p < 0.01); specificity 59 and 86% (p < 0.001), respectively; accuracy 77% for both. The addition of the wall motion response to dobutamine to the assessment of the nonviable segments by perfusion (60% cutoff) increased the sensitivity from 70 to 85% (p = 0.001) and the negative predictive value from 70 to 81% (p = 0.009); the positive predictive value remained high (86 vs. 82%). No additive value of wall motion response to dobutamine was demonstrated for nonviable segments by perfusion with a 50% cutoff. CONCLUSION: Dobutamine sestamibi-gated SPECT is a feasible method for the analysis of myocardial perfusion, function, and contractile reserve of individual myocardial segments in patients with ischemic cardiomyopathy. Viability assessment based on a threshold of 60% uptake of sestamibi, with the addition of the wall motion response to dobutamine in the nonviable segments, seems to yield better predictive values for wall motion improvement after CABG.

[Preoperative cardiac risk evaluation in non cardiac surgery].

Cardiovascular complications are important causes of morbidity with major non cardiac procedures. Preoperative risk stratification relies on the identification of the cardiac problem, its stability, its severity and previous treatment. The approach to risk stratifying preoperative patients should be performed by accepted guidelines used for patients with suspected coronary artery disease (CAD) or known CAD and not as an "obligatory test" prior to operation. Risk stratification is based on clinical predictors, stress testing, including cardiac imaging if necessary, and the kind of operation. Most of the tests are noninvasive and some invasive tests conducted are intended to identify myocardial ischemia and critical lesions of the coronary arteries. Most of the patients are able to undergo elective procedures without any problem with the perioperative cardiac event rate of up to 2% considered as an accepted goal. The use of invasive diagnostic and therapeutic methods, such as cardiac catheterization, PCI, CABG, has to be restricted only to patients who are at very high risk. The partial reduction of the cardiac event rate in the short term and monitoring for 24 hours after operation is most important, as well as the administration of beta blockers, starting prior to surgery. Furthermore, long term follow-up for cardiac events in these patients in essential, as the clinical predictors and cardiac tests performed for preoperative risk stratification are also used for long term prognosis.

Feasibility of myocardial perfusion SPECT with prone and half-time imaging.

BACKGROUND: Myocardial perfusion imaging with single-photon emission tomography (SPECT) is associated with reduced specificity due to tissue attenuation. This can be corrected by prone imaging while necessitating additional imaging time. Image processing with iterative reconstruction allows for a half-time (HT) acquisition. OBJECTIVE: To assess the feasibility of myocardial perfusion with SPECT using prone imaging with HT acquisition. METHODS: Ninety-one patients referred for SPECT myocardial perfusion imaging and weighing up to 90 kg were enrolled for HT supine and prone SPECT protocol. Patients with known myocardial infarction were excluded. HT prone imaging was performed when supine imaging was visually equivocal or abnormal. Image quality was compared for each patient between supine and prone imaging. RESULTS: Acquisition time was 17.9 ± 2.9 min in the HT group compared with 31.8 ± 5.8 min in patients imaged with full-time acquisition. Image quality was good or excellent in 85.7% of studies in a supine position and in 81.3% of studies in the prone position (P = 0.25). No study was considered as nondiagnostic. Prone imaging reduced the rate of equivocal scans from 40.7 to 15.4% and of ischemic studies from 34.1 to 7.7%. In the study population, 80% of inferior and septal defects were corrected by the prone position. CONCLUSION: In a selected population, HT prone and supine imaging is feasible and is associated with a good image quality in most studies whereas acquisition time is reduced almost by half.

Myocardial perfusion profile in a young population with and without known coronary artery disease: comparison by gender.

BACKGROUND: More and more young people are being referred for evaluation or screening for coronary artery disease (CAD). However, the value of myocardial perfusion imaging (MPI) in this population is unclear, especially in the absence of symptoms. METHODS: The study sample included 1765 consecutive patients less than 51 years old who were referred to a major medical center for stress/rest MPI study. Clinical and MPI variables were compared between patients with and without known CAD, by gender. RESULTS: There were 1346 (76%) men and 419 (24%) women of mean age 44 +/- 6 years; 461 (26%) had known CAD. Stress-induced ischemia was detected in 321 patients (18.2%) and significant ischemia in 131 (7.4%); there was no difference in the rate or severity of ischemia by presence of symptoms. Among those without known CAD, the rate of stress-induced ischemia by MPI was significantly lower in women than men. On logistic regression analysis, the independent predictors of ischemia in men were high cholesterol, diabetes, angina during stress testing, ST depression, and smoking (P<.0001); and in women, the independent predictors were diabetes and high cholesterol. CONCLUSION: Known CAD and stress-induced ischemia are significantly more prevalent in young men than in young women, irrespective of risk factors. The independent predictors of ischemia differ between men and women.

Prognostic value of myocardial perfusion imaging in symptomatic and asymptomatic patients after percutaneous coronary intervention.

The aim of this study was to evaluate the value of myocardial perfusion imaging (MPI) in predicting major adverse cardiovascular events (MACE) in symptomatic and asymptomatic patients after percutaneous coronary intervention (PCI). We revised retrospectively patients after PCI that underwent MPI and were followed for a year for the presence of MACE. We found no differences in the incidence of MACE between symptomatic and asymptomatic patients. On multivariate analysis, the presence of ischemia by MPI was the most important independent predictor of MACE (OR 5.09, CI 95% 2.15-12.05, p < 0.001). The presence of myocardial ischemia by MPI performed after PCI, and no symptom status, predicts a worse outcome during 1 year of follow-up.