Normal Myocardial Perfusion SPECT Research Articles

Improved detection of coronary artery disease by CZT regional coronary blood flow evaluation

IntroductionCZT cameras have enabled the noninvasive quantification of myocardial flow reserve (MFR), an important physiologic measure. This study aimed to compare myocardial perfusion SPECT (MPS) with or without MFR evaluation for the detection of obstructive coronary artery disease (CAD).Methods48 patients with CAD (>50% obstruction) detected at invasive coronary angiography or CT angiography underwent dipyridamole MPS and MFR evaluation within 30 days. A 1-day protocol (rest-stress) was used to quantify MFR. The acquisition of dynamic rest and stress images was initiated simultaneously to 99mTc sestamibi injection (370 and 1,110 MBq, respectively), both lasting for 11 min, followed by 5-min imaging. Pharmacologic stress with dipyridamole (0.56 mg/kg for 4 min) was performed with the patient positioned in the CZT camera. The images were processed and time-activity curves were generated, calculating global and regional MFR in a semiautomatic software. A global or regional MFR <2 was considered abnormal. MPS perfusion images were classified as normal or abnormal. The images were interpreted by experienced physicians blinded to the results of MFR and coronary angiography/CT.ResultsMean age of the population was 61 ± 9 years, 54.2% female. Twenty patients (41.7%) had single-vessel CAD, 22 (45.8%) 2-vessel CAD and 6 (12.5%), triple-vessel CAD. Among the 82 vessels with obstruction, 48 had perfusion abnormalities in MPS and 60 had reduced MFR, while among the normal vessels, had 54 normal MPS and 52 had preserved MFR. The sensitivity of MFR (69%) was higher than that of MPS (55.2%), without significant changes in specificity (86 vs. 83.7%).ConclusionsMFR in the CZT camera is more sensitive for the detection of CAD than perfusion abnormalities in MPS, especially in patients with multivessel CAD.

The incremental value of exercise ECG to myocardial perfusion SPECT for prediction of cardiac events

Abstract Background Both myocardial perfusion SPECT (MPS) and exercise ECG (Ex-ECG) are known to carry prognostic information in patients with chronic coronary syndrome (CCS). However, it is not fully understood if combining MPS and Ex-ECG results improves risk prediction. Current guidelines no longer recommend Ex-ECG for diagnostic evaluation of CCS, but adding Ex-ECG results to MPS could be of incremental prognostic importance. Purpose The study aimed to assess the incremental prognostic value of Ex-ECG to MPS results in patients with CCS. Methods A single-center study of 908 consecutive patients with CCS (age 63±9 years, 49% male) who underwent a MPS with Ex-ECG. Subjects were followed for five years. The clinical endpoint was a composite of cardiovascular death (CV), acute myocardial infarction (AMI), unstable angina and unplanned PCI. National registry data and electronic medical charts were used for end point allocation. Results Combining the findings of MPS and Ex-ECG resulted in concordant evidence of ischemia in 72 patients (8%) or absence of ischemia in 634 patients (70%). Dis-concordant results were found in 202 patients (22%; MPS−/Ex-ECG+, n=126 and MPS+/Ex-ECG−, n=76). During follow-up 95 composite cardiac events occurred (CV deaths n=6, AMI n=27, unstable angina n=34 and unplanned PCI n=28). Kaplan-Meier curves display an increased risk of cardiac events in patients with any combination of abnormal stress test results (Figure 1). In a multivariable regression model (adjusting for age, sex, smoking, known IHD, diabetes, dyslipidaemia and exercise capacity) MPS was the strongest predictor of cardiac events regardless of Ex-ECG results (MPS+/Ex-ECG−, Hazard ratio (HR) = 3.0, p=0.001 or MPS+/Ex-ECG+, HR=4.0, p<0.001). However, an abnormal Ex-ECG almost doubled the risk of event in subjects with a normal MPS (MPS−/Ex-ECG+, HR=1.9, p=0.04). Conclusions Combining the results from MPS and Ex-ECG in patients with chronic coronary syndrome lead to an improved prediction of future cardiac events. Even though MPS is the stronger predictor, there is an incremental prognostic value of adding data from Ex-ECG to MPS, especially in patients with normal MPS findings. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Swedish Heart and Lung Foundation, Region of Scania

Clinical Validation of Japanese Normal Myocardial Perfusion Imaging Databases Using Semi-conductor Gamma Camera (D-SPECT): Japanese Society of Nuclear Cardiology Working Group Reports.

Objective: A working group (WG) of the Japanese Society of Nuclear Cardiology (JSNC) determined Japanese normal databases of myocardial perfusion single-photon emission computed tomography (SPECT) on semi-conductor gamma camera (D-SPECT), and the aim of this study was to validate its clinical utility. Materials and methods: The normal myocardial perfusion SPECT (MPS) databases of Japanese patients in the 201Tl stress/redistribution protocol (201Tl protocol), 99mTc stress/rest or rest/stress protocol (99mTc protocol), and rest 99mTc/stress 201Tl simultaneous acquisition dual-isotope protocol (SDI protocol) were created by JSNC WG. The WG collected clinical cases for the 201Tl protocol (male/female [m/f], 8/8), 99mTc protocol (m/f, 9/7), and SDI protocol (m/f, 10/10) from WG participating hospitals. Four WG members read those clinical cases on a 17-segment and 5-point scale (0-4). Using the most frequent values as the score for each segment, weighted κ values were calculated with the scores obtained from quantitative perfusion software (QPS). Results: Weighted κ values were as follows; 201Tl stress/female, 0.77; 201Tl rest/female, 0.74; 201Tl stress/male, 0.81; 201Tl rest/male, 0.68; 99mTc stress/female, 0.77; 99mTc rest/female, 0.62; 99mTc stress/male, 0.77; 99mTc rest/male, 0.75; SDI stress/female, 0.87; SDI rest/female, 0.82; SDI stress/male, 0.87; SDI rest/male, 0.85. Conclusions: The diagnostic accuracy of Japanese MPS normal databases on D-SPECT were comparable with nuclear cardiology expert reading and further clinical applications are expected.

Clinical usefulness of quantification of myocardial blood flow and flow reserve using CZT-SPECT for detecting coronary artery disease in patients with normal stress perfusion imaging

BackgroundRelative myocardial perfusion imaging can misdiagnose “balanced” ischemia caused by coronary artery disease (CAD). We assessed the feasibility of myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) using dynamic single-photon emission computed tomography (SPECT) with a cadmium-zinc-telluride (CZT) camera for estimating underlying CAD in patients with normal stress myocardial perfusion SPECT (MPS). Methods125 patients with normal stress MPS (summed stress score ≤3) were enrolled. All patients underwent coronary angiography (CAG) and stress/rest 201Tl dynamic SPECT for MBF and MPR calculation. The diagnostic accuracy of both these quantitative values and other clinical risk factors for predicting occult CAD were validated by CAG. ResultsMPR was 2.85 in patients with no CAD, 2.47 with 1-, 1.98 with 2-, and 1.76 with 3-vessel CAD. The patient’s age, morbidity of diabetes mellitus (DM), chronic kidney disease (CKD), stress MBF, and MPR were significantly associated with the presence of CAD (age, p=0.02; DM, p=0.005; CKD, p=0.005; creatinine level, p= 0.012, stress MBF, p=0.019, and MPR, p<0.001). Independent predictors in the multivariate regression analysis were as follows: DM, p=0.011, CKD, p=0.028, and MPR, p<0.001. The combined index was calculated from three independent predictors. Area under the receiver operating characteristic curve was 0.75 for MPR and 0.81 for the combined index. To identify CAD, sensitivity, and specificity for MPR were 77% and 66%, and for the combined index they were 79% and 66%, respectively. ConclusionQuantification of MPR and MBF using dynamic SPECT with a CZT camera can be useful to identify balanced ischemia caused by occult CAD in patients with normal stress MPS findings.

29Prognostic safety of automatic cancellation of rest myocardial perfusion scan by machine learning: a report from multicenter REFINE SPECT registry of new generation SPECT

Abstract Background We aimed to develop a machine learning (ML) computer score derived from stress imaging and clinical data, which indicates if the rest scan could be automatically and safely canceled in the routine stress/rest myocardial perfusion SPECT (MPS). Methods A total of 20414 stress/rest cases from the REFINE SPECT registry collected from 5 sites in 3 countries with Tc-99m-based MPS images, clinical data, and clinical follow-up were included in the study. All images were automatically processed at our Medical Center. The automatically generated myocardial contours were checked by experienced technologists. In total, 93 variables (26 clinical, 17 stress-test, and 50 stress-imaging variables) were used to build a LogitBoost model for prediction of adverse events (AE), including coronary revascularization, death, myocardial infarction, and unstable angina. 10-fold cross-validation was performed to separate test from validation data for the assessment of ML. The overall ML predictive performance was compared to quantitative (stress total perfusion deficit [TPD]) by the area under the receiver operating characteristic curves (AUC). ML cut-off (ML1) to simulate the decision of cancellation of the rest scan was set to result in the same % of normal scans as these determined by the normal clinical reader diagnosis on a 4-point scale in the whole population, or the same % of scans with visual summed stress scores (SSS) = 0 in the subpopulation with available SSS. A second ML cutoff (ML2) was established to achieve a 1% annual risk of AE. The annual risk of AE of the normal ML score was compared with normal clinical diagnosis and with the finding of SSS = 0. Results The mean follow-up interval was 4.7±1.5 years. Overall, 3542 AE were observed (3.7% annual risk). The AUC for AE was higher for ML (0.780±0.005) than for stress TPD (0.698±0.006) (p&lt;0.001). Normal clinical diagnosis was reported in 60% cases. In 70% (14242 scans) with available segmental scores, 53% had SSS=0. ML1 and ML2 thresholds were compared with normal visual diagnosis and with SSS = 0 for AE (Figure). ML1 achieved a lower annual risk (1.5%) than normal clinical diagnosis (2.1%) or SSS = 0 (1.6% versus 2.3%) (p&lt;0.001). The more conservative ML2 threshold with a 1% annual risk of AE resulted in a 40% canceling rate. Figure 1 Conclusion ML could be used to automatically cancel the rest MPS scan with the same proportion as using normal visual MPS reading, but with significantly lower AE rate in stress-only scans. Acknowledgement/Funding R01HL089765 from the National Heart, Lung, and Blood Institute/National Institutes of Health (NHLBI/NIH)

Coronary calcium score influences referral for invasive coronary angiography after normal myocardial perfusion SPECT

BackgroundIn patients with normal SPECT but persistent complaints, invasive angiography may exclude obstructive coronary disease. We assessed whether high coronary artery calcium (CAC) scores are associated with increased referral for invasive angiography following normal SPECT. Methods and results2286 consecutive patients (mean age 60 ± 12, 39% male) with normal SPECT were assessed. All patients underwent simultaneous CAC scoring. Patients were categorized into four groups based on their CAC score: CAC = 0 (n = 694), CAC 1 to 100 (n = 891), CAC 101 to 400 (n = 368), and CAC >400 (n = 333). The decision to perform angiography was left to the discretion of treating physician. Follow-up angiography was confined to the first 60 days after SPECT. Occurrence of MACE (late revascularization, myocardial infarction or death) was recorded. Overall, 100 patients (4.4%) underwent early angiography with increasing rates in higher CAC score groups (1.0%, 2.6%, 8.4%, and 11.7%), respectively, P < .001). A CAC score >400 (OR 3.56, 95% CI 2.19 to 5.77, P < .001) was independently associated with referral to angiography. Similarly, CAC score >400 was an independent predictor for MACE (HR 9.26, 95% CI 5.06 to 16.93). Early angiography did not influence prognosis (HR 1.57, 95% CI 0.91 to 2.73). ConclusionsCAC scoring impacts clinical decision-making and increases referral rates for invasive angiography after normal SPECT.

Prevalence and predictors of myocardial ischemia by preoperative myocardial perfusion single photon emission computed tomography in patients undergoing noncardiac surgery.

BACKGROUNDThe prevalence and predictors of myocardial ischemia before noncardiac surgery are unknown. In addition the predictive value of myocardial perfusion single-photon emission computed tomography (SPECT) before noncardiac in individual patients is uncertain.OBJECTIVEEvaluate the prevalence and predictors of myocardial ischemia before noncardiac surgery, and determine the postoperative cardiac outcome based on results of myocardial perfusion SPECT.DESIGNRetrospective.SETTINGSingle tertiary care center.PATIENTS AND METHODSWe reviewed the records of adult patients diagnosed with myocardial ischemia by myocardial perfusion SPECT who were undergoing noncardiac surgery. Myocardial perfusion SPECT had been performed within 4 weeks prior to noncardiac surgery requiring general anesthesia.MAIN OUTCOME MEASURESPrevalence of abnormal myocardial perfusion SPECT results on preoperative evaluation; abnormal myocardial perfusion SPECT results as a predictor for postoperative cardiac events such as cardiac death, nonfatal myocardial infarction, and unstable angina.RESULTSOf 131 patients who underwent noncardiac surgery from February 2015 to April 2016, 84 (64%) patients were female and the mean (SD) age was 64.1 (13.6) years. The prevalence of abnormal myocardial perfusion SPECT was 18% (24 of 131). Normal myocardial perfusion SPECT was highly predictive (up to 100%), but a positive myocardial perfusion SPECT had low positive predictive value (4%). Variables associated with an abnormal myocardial perfusion SPECT included ischemic heart disease, congestive heart failure, ASA score of 3 or more, limited exercise capacity (less than 4 METs), male sex, hypercholesterolemia, hypertension, smoking, and abnormal ECG. In a multivariable analysis, history of ischemic heart disease and history of smoking were significant predictors of abnormal myocardial perfusion SPECT (P=.001, and .029, respectively).CONCLUSIONSBecause of the low positive predictive value of myocardial perfusion SPECT, utilization of the technique in the workup of cardiac patients undergoing noncardiac surgery has been inappropriate. Myocardial perfusion SPECT should be restricted to only clearly defined appropriate use criteria.LIMITATIONSRelatively small number of patients and retrospective design.

The prognostic signifi cance of normal technetium-99m MIBI myocardial perfusion spect imaging over a four-year follow-up period

normal Tc-99m MIBI myocardial perfusion study has previously been shown to indicate a benign prognosis. Our aim was to determine the longer term prognosis of a normal study in our patient population. Methods: A retrospective evaluation of 209 patients with a normal Tc-99m MIBI study was performed. Follow-up data was obtained in 157 patients, with complete follow-up in 121 (mean follow-up period of 56 months). In 36 patients only partial follow-up was possible (32 months follow-up). No follow-up data, except for the possible registration of deaths, could be obtained in 52. Patients were evaluated for the occurrence of primary or secondary cardiac events. Results: The study group had a moderate pre-test probability for coronary artery disease (48 + 30.7%). Two possible cardiac deaths occurred (cardiac death rate of 0.95%). No primary events occurred in the group with complete follow-up, but 6 secondary events were recorded (cardiac event rate of 4.9%). No primary or secondary events occurred in the partial follow-up group during the follow-up period. The incidence of secondary or non-fatal primary events in this group for the period after they were lost to follow-up or in the group with no follow-up could not be ascertained. There was, however, no statistically significant difference between these groups regarding age, pre-test probability and exercise parameters. Conclusion: Similar to the findings with Tl-201, our study indicates a favourable longer term prognosis after a normal Tc-99m MIBI study.

Usefulness of the novel risk estimation software, Heart Risk View, for the prediction of cardiac events in patients with normal myocardial perfusion SPECT.

Myocardial perfusion single-photon emission-computed tomography (SPECT) can predict cardiac events in patients with coronary artery disease with high accuracy; however, pseudo-negative cases sometimes occur. Heart Risk View, which is based on the prospective cohort study (J-ACCESS), is a software for evaluating cardiac event probability. We examined whether Heart Risk View was useful to evaluate the cardiac risk in patients with normal myocardial perfusion SPECT (MPS). We studied 3461 consecutive patients who underwent MPS to detect myocardial ischemia and those who had normal MPS were enrolled in this study (n=698). We calculated cardiac event probability by Heart Risk View and followed-up for 3.8±2.4years. The cardiac events were defined as cardiac death, non-fatal myocardial infarction, and heart failure requiring hospitalization. During the follow-up period, 21 patients (3.0%) had cardiac events. The event probability calculated by Heart Risk View was higher in the event group (5.5±2.6 vs. 2.9±2.6%, p<0.001). According to the receiver-operating characteristics curve, the cut-off point of the event probability for predicting cardiac events was 3.4% (sensitivity 0.76, specificity 0.72, and AUC 0.85). Kaplan-Meier curves revealed that a higher event rate was observed in the high-event probability group by the log-rank test (p<0.001). Although myocardial perfusion SPECT is useful for the prediction of cardiac events, risk estimation by Heart Risk View adds more prognostic information, especially in patients with normal MPS.

Very high coronary artery calcium score with normal myocardial perfusion SPECT imaging is associated with a moderate incidence of severe coronary artery disease

Very high coronary artery calcium score with normal myocardial perfusion SPECT imaging is associated with a moderate incidence of severe coronary artery disease

High-Sensitivity and High-Resolution SPECT/CT Systems Provide Substantial Dose Reduction Without Compromising Quantitative Precision for Assessment of Myocardial Perfusion and Function

There is increasing concern about radiation exposure from myocardial perfusion SPECT (MPS). γ-cameras with solid-state cadmium-zinc-telluride (CZT) detectors have better count sensitivity and spatial resolution than conventional sodium iodine detectors, allowing for significant reductions in radiotracer dose or acquisition time. This study aimed to demonstrate the capability of a hybrid CZT SPECT/64-slice CT system for dose reduction and to determine the maximal reduction possible without compromising image quality or the quantification precision of clinical MPS. The imaging data of patients with normal myocardial perfusion and 30 patients with mid-sized to large perfusion defects who had undergone stress (99m)Tc-tetrofosmin MPS were postprocessed. Low-dose (361 ± 60 MBq) and high-dose (725 ± 142 MBq) (99m)Tc-tetrofosmin scans were included, with 6-min and 4-min scanning times, respectively. List-mode SPECT data were reconstructed with CT-based attenuation correction and with full as well as 50% and 75% reductions in acquisition time to simulate the corresponding relative dose reductions. The reconstructed SPECT images were analyzed to calculate global MPS defect size and regional defect size for 3 coronary artery territories-left anterior descending, left circumflex, and right-as well as left ventricular (LV) volume and ejection fraction. For patients with normal MPS results, there were no differences in defect size, LV volume, or ejection fraction, regardless of whether 50% or 75% reduction was used. For patients with abnormal MPS results, at a 50% reduction there was a significant difference in global defect size but not in regional defect size in the left anterior descending, left circumflex, and right coronary artery territories, whereas at a 75% reduction the difference was statistically significant in all territories, including the difference in global defect size. Nonetheless, differences in the defect size were minimal. The LV end-diastolic and end-systolic volumes and LV ejection fraction were not significantly different, regardless of whether 50% or 75% dose reduction was used. Ultra-low-dose (<190 MBq) MPS even with short imaging times (<6 min) is feasible using a hybrid CZT SPECT/CT camera without compromising image quality or significantly altering quantification of myocardial perfusion or LV function. We demonstrated that an additional 50% reduction in the current low-dose recommendations from the American Society of Nuclear Cardiology guidelines for (99m)Tc-labeled MPS is highly feasible while retaining short imaging protocols.

Transischemic Dilation as Predictor for Heart Failure in SPECT Data Analysis of Patients with Heart Disease

Objectives: Transient ischemic dilation ratio (TID) of the left ventricle is a significant predictor of future cardiac events in patients with otherwise normal myocardial perfusion SPECT. TID is a marker for subendocardial perfusion reduction after exercise in gated SPECT studies. Increased TID is correlated with concentric or excentric left-ventricular hypertrophy, or increased pre- or afterload conditions. This parameter is suggested to be an indicator for deterioration of subendocardial perfusion and offers a more precise presumptive screening for myocardial dysfunction.

Follow-up of patients with good exercise capacity in stress test with myocardial single-photon emission computed tomography (SPECT)

The evaluation of coronary artery disease (CAD) can be performed with stress test and myocardial SPECT tomography. To assess the predictive value of myocardial SPECT using stress test for cardiovascular events in patients with good exercise capacity. We included 102 males aged 56 ± 10 years and 19 females aged 52 ± 10 years, all able to achieve 10 METs and ≥ 85% of the theoretical maximum heart rate and at least 8 min in their stress test with gated 99mTc-sestamibi SPECT. Eighty two percent of patients were followed clinically for 33 ± 17 months. Sixty seven percent of patients were studied for CAD screening and the rest for known disease assessment. Treadmill stress test was negative in 75.4%; 37% of patients with moderate to severe Duke Score presented ischemia. Normal myocardial perfusion SPECT was observed in 70.2%. Reversible defects appeared in 24.8% of cases, which were of moderate or severe degree (> 10% left ventricular extension) in 56.6%. Only seven cases had coronary events after the SPECT. Two major (myocardial infarction and emergency coronary revascularization) and 5 minor events (elective revascularization) ere observed in the follow-up. In a multivariate analysis, SPECT ischemia was the only statistically significant parameter that increased the probability of having a major or minor event. Nearly a quarter of our patients with good exercise capacity demonstrated reversible defects in their myocardial perfusion SPECT. In the intermediate-term follow-up, a low rate of cardiac events was observed, being the isotopic ischemia the only significant predictive parameter.

Very high coronary artery calcium score with normal myocardial perfusion SPECT imaging is associated with a moderate incidence of severe coronary artery disease.

PurposeMyocardial perfusion imaging (MPI) has limitations in the presence of balanced multivessel disease (MVD) and left main (LM) coronary artery disease, occasionally resulting in false-normal results despite the high cardiovascular risk associated with this condition. The purpose of this study was to assess the incidence of severe coronary artery disease (CAD) in the presence of a very high Agatston coronary artery calcium (CAC) score (>1,000) in stable symptomatic patients without known CAD but with normal MPI results.MethodsA total of 2,659 prospectively acquired consecutive patients were referred for MPI and evaluation of CAC score by CT. Of this patient population, 8 % (222/2,659) had ischemia without myocardial infarction (MI) on MPIand 11 % (298/2,659) had abnormal MPI (MI and/or ischemia). On presentation 1 % of the patients (26/2,659) were symptomatic, had a CAC score >1,000 and normal MPI results. The definition of normal MPI was strict and included a normal hemodynamic response without ischemic ECG changes and normal imaging, particularly absence of transient ischemic dilation. All of these 26 patients with a CAC score >1,000 and normal MPI findings underwent cardiac catheterization.ResultsOf these 26 patients, 58 % (15/26) had severe disease (≥70 % stenosis) leading to revascularization. Of this group, 47 % (7/15) underwent percutaneous intervention, and 53 % (8/15) underwent coronary artery bypass grafting. All of these 15 patients had either MVD (14/15) or LM coronary artery disease (1/15), and represented 0.6 % (15/2,659) of all referred patients (95 % CI 0.3 – 0.9 %). The majority, 90 % (8/9), had severe CAD with typical chest pain.ConclusionA very high CAC score (>1,000) with normal MPI in a small subset of symptomatically stable patients was associated with a moderate incidence of severe CAD (95 % CI 37 – 77 %). Larger studies and/or a meta-analysis of small studies are needed to more precisely estimate the incidence of CAD in this population. This study also supports the concept that a normal MPI result in patients with severe CAD may be due to balanced MVD.Electronic supplementary materialThe online version of this article (doi:10.1007/s00259-015-3072-z) contains supplementary material, which is available to authorized users.

Warranty periods for normal myocardial perfusion stress SPECT

BackgroundTo assess different warranty periods following a normal myocardial perfusion SPECT based on patients’ clinical characteristics and the type of stress performed. Methods and ResultsA study was done of 2,922 consecutive patients (62.9 ± 13 years; 53.4% women) with a normal stress-rest SPECT. The warranty period was defined as the period during which patients remained at a low risk (<1% events/year) of total mortality (TM), or hard events (HE) (cardiac death or non-fatal myocardial infarction). Of these patients, 2,051 were given an exercise myocardial perfusion imaging (Ex-MPI); 461 submaximal exercise plus dipyridamole (Ex+Dipy-MPI); and 410 dipyridamole (Dipy-MPI). During a mean follow-up of 5 ± 3.3 years, a significant reduction (P < .05) of the warranty period for TM (13.5, 9.6 and 8 months) and HE (34.8, 20.5 and 8.2 months) was observed, for Ex-MPI, Ex+Dipy-MPI and Dipy-MPI, respectively. Other warranty period determinants were the clinical variables of age, sex, diabetes and known coronary artery disease. An abnormal left ventricular ejection fraction on gated-SPECT also significantly shortened the warranty period for HE in patients undergoing Ex+Dipy-MPI (P = .001) or Dipy-MPI alone (P = .007). ConclusionsThe warranty period for a normal stress-rest SPECT is highly variable since it is primarily determined by the type of stress, the patient’s clinical characteristics and LVEF.

IMPACT OF ZERO CORONARY CALCIUM IN CARDIOVASCULAR RISK STRATIFICATION OF PATIENTS UNDERGOING RENAL TRANSPLANT EVALUATION

We hypothesized that zero calcium score (ZCS) would predict normal myocardial perfusion SPECT in patients with end stage renal disease (ESRD) undergoing evaluation for renal transplant. We enrolled 354 consecutive patients (65% men, mean age 52 ± 11 years) without known coronary artery disease

Long-term mortality following normal exercise myocardial perfusion SPECT according to coronary disease risk factors

BackgroundWhile normal exercise myocardial perfusion imaging (SPECT-MPI) is a robust predictor of low short-term clinical risk, there is increasing interest in ascertaining how clinical factors influence long-term risk following SPECT-MPI. MethodsWe evaluated the predictors of outcome from clinical data obtained at the time of testing in 12,232 patients with normal exercise SPECT-MPI studies. All-cause mortality (ACM) was assessed at a mean of 11.2 ± 4.5 years using the Social Security Death Index. ResultsThe ACM rate was 0.8%/year, but varied markedly according to the presence of CAD risk factors. Hypertension, smoking, diabetes, exercise capacity, dyspnea, obesity, higher resting heart rate, an abnormal ECG, LVH, atrial fibrillation, and LVEF < 45% were all predictors of increased mortality. Risk factors were synergistic in predicting mortality: annualized age and gender-adjusted ACM rates ranged from only 0.2%/year among patients exercising for >9 minutes having none of three significant risk factors (among hypertension, diabetes, and smoking) to 1.6%/year among patients exercising <6 minutes and having ≥2 of these three risk factors. The age and gender-adjusted hazard ratio for mortality was increased by 7.3 (95% confidence interval 5.5-9.7) in the latter patients compared to those patients who exercised >9 minutes and had no significant risk factors (P < .001). ConclusionsLong-term mortality risk varies markedly in accordance with baseline CAD risk factors and functional capacity among patients with normal exercise SPECT-MPI studies. Further study is indicated to determine whether the prospective characterization of both short-term and long-term risks following the performance of stress SPECT-MPI leads to improved clinical management.

12-Year outcome after normal myocardial perfusion SPECT in patients with known coronary artery disease

BackgroundPrevious studies have reported a favorable outcome of patients with normal single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). The aim of this study was to assess the very long-term prognosis of patients with known coronary artery disease (CAD) and normal SPECT MPI results. MethodsThe population consisted of 266 patients with known CAD (defined as a healed myocardial infarction and/or a previous coronary revascularization), who underwent exercise bicycle or dobutamine-atropine stress SPECT MPI and had normal perfusion during stress and at rest. End points during follow-up were all-cause mortality, cardiac mortality, and nonfatal myocardial infarction. Univariate and multivariate analyses were performed to identify predictors of long-term outcome. ResultsFollow-up was completed in 261 (98%) patients. During a median follow-up of 12 years, 94 (36%) patients died, of which 26 (10%) died due to cardiac causes, and 15 (6%) had a nonfatal myocardial infarction. The annualized mortality rate was 3.1%, annualized cardiac mortality rate was 0.9%, and the annualized event rate for cardiac death and/or nonfatal infarction was 1.2%. Independent predictors of total mortality were age, diabetes mellitus, and rate-pressure product at peak stress. Independent predictors of cardiac mortality were age, male gender, and rate-pressure product at peak stress. ConclusionPatients with known CAD and a normal SPECT MPI study have a favorable long-term prognosis. Clinical and stress test variables can be used to identify patients with a higher risk status.

Prognostic value of stress-gated 99m-technetium SPECT myocardial perfusion imaging: Risk stratification of patients with multivessel coronary artery disease and prior coronary revascularization

BackgroundThis study assessed the prognostic value of stress-gated 99mTc-sestamibi myocardial perfusion SPECT (MPS) in patients with multivessel coronary artery disease (CAD) and prior revascularization according to the presence and severity of ischemia. Methods and ResultsWe studied the outcome of 472 patients with multivessel CAD and prior revascularization (coronary angioplasty, 290 patients; bypass surgery, 182 patients), who underwent exercise or dipyridamole 99mTc-sestamibi MPS for evaluation of ischemia. Visual scoring of perfusion images used 20 segments and a 5-point scale. Gated post-stress EF was automatically calculated. Endpoints included hard events: cardiac death (CD) and nonfatal myocardial infarction (MI). During a mean follow-up of 3.0 ± 1.0 years, 37 hard events occurred, including CD in 15 (3%) and MI in 22 (5%) patients. In a risk-adjusted multivariable Cox model, a history of prior MI, diabetes, abnormal MPS, moderate-to-severe ischemia, and post-stress EF <35% were important predictors of cardiac events. Four-year risk-adjusted survival was 97.9% for normal MPS, 87.3% for abnormal MPS with ischemia, and 82.1% for moderate-to-severe ischemia. ConclusionsAmong patients with previous coronary revascularization, stress-gated 99mTc-sestamibi MPS provides prognostic information for the prediction of cardiac events. A normal perfusion scan confers an excellent prognosis and an exceedingly low hard event rate (<1%/year). The presence of moderate-to-severe ischemia or a post-stress EF <35% identifies patients at highest risk of subsequent cardiac events.

15-Year outcome after normal exercise 99mTc-sestamibi myocardial perfusion imaging: What is the duration of low risk after a normal scan?

ObjectiveThe goal of this study was to evaluate the very long-term outcome after normal exercise 99mTc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT). Exercise 99mTc-sestamibi SPECT is widely used for risk stratification, but data on very long-term outcome after a normal test are scarce. MethodsA consecutive group of 233 patients (122 men, mean age 54 ± 12 years) with known or suspected coronary artery disease (CAD) underwent exercise 99mTc-sestamibi SPECT and had normal myocardial perfusion at exercise and at rest. Follow-up endpoints were all-cause mortality, cardiac mortality, nonfatal myocardial infarction, and coronary revascularization. Predictors of outcome were identified by Cox proportional hazard regression models using clinical and exercise testing variables. ResultsDuring a mean follow-up of 15.5 ± 4.9 years, 41 (18%) patients died, of which 13 were cardiac deaths. A total of 18 (8%) patients had a nonfatal myocardial infarction, and 47 (20%) had coronary revascularization. The annualized event rates for all-cause mortality, cardiac mortality, cardiac mortality/nonfatal infarction, and major adverse cardiac events were, respectively, 1.1%, 0.3%, 0.7%, and 1.8%. Multivariate analysis demonstrated that the variables age, male gender, diabetes, diastolic blood pressure at rest, rate pressure product at rest, peak exercise heart rate, and ST segment changes were independent predictors of major adverse cardiac events. ConclusionPatients with suspected or known CAD and normal exercise 99mTc-sestamibi myocardial perfusion SPECT have a favorable 15-year prognosis. Follow-up should be closer in patients with known CAD, and/or having clinical and exercise parameters indicating higher risk status.