Prognostic value of exercise stress technetium-99m-tetrofosmin myocardial perfusion imaging in patients with normal baseline electrocardiograms

Incremental Value of Exercise ECG to Myocardial Perfusion Single-Photon Emission Computed Tomography for Prediction of Cardiac Events

Background Both myocardial perfusion single-photon emission computed tomography (MPS) and exercise ECG (Ex-ECG) carry prognostic information in patients with stable chest pain. However, it is not fully understood if combining the findings of MPS and Ex-ECG improves risk prediction. Current guidelines no longer recommend Ex-ECG for diagnostic evaluation of chronic coronary syndrome, but Ex-ECG could still be of incremental prognostic importance. Methods and Results This study comprised 908 consecutive patients (age 63.3±9.4 years, 49% male) who performed MPS with Ex-ECG. Subjects were followed for 5 years. The end point was a composite of cardiovascular death, acute myocardial infarction, unstable angina, and unplanned percutaneous coronary intervention. National registry data and medical charts were used for end point allocation. Combining the findings of MPS and Ex-ECG resulted in concordant evidence of ischemia in 72 patients or absence of ischemia in 634 patients. Discordant results were found in 202 patients (MPS-/Ex-ECG+, n=126 and MPS+/Ex-ECG-, n=76). During follow-up, 95 events occurred. Annualized event rates significantly increased across groups (MPS-/Ex-ECG- =1.3%, MPS-/Ex-ECG+ =3.0%, MPS+/Ex-ECG- =5.1% and MPS+/Ex-ECG+ =8.0%). In multivariable analyses MPS was the strongest predictor regardless of Ex-ECG findings (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 in subjects with normal MPS (MPS-/Ex-ECG+, HR, 1.9, P=0.04). Conclusions In patients with chronic coronary syndrome, combining the results from MPS and Ex-ECG led to improved risk prediction. Even though MPS is the stronger predictor, there is an incremental value of adding data from Ex-ECG to MPS, especially in patients with normal MPS.

Negative predictive value of stress myocardial perfusion imaging and coronary computed tomography angiography: A meta-analysis

BACKGROUND

Comparing the prognostic value of a negative finding by stress single-photon emission computed tomography myocardial perfusion imaging (MPI) and coronary computed tomography angiography (CCTA) may be useful to evaluate how better identify low-risk patients. We performed a meta-analysis to compare the long-term negative predictive value (NPV) of normal stress MPI and normal CCTA in subjects with suspected coronary artery disease (CAD).

METHODS AND RESULTS

Studies published between January 2000 and November 2016 were identified by database search. We included MPI and CCTA studies that followed-up ≥100 subjects for ≥5 years and providing data on clinical outcome for patients with negative tests. Summary risk estimates for normal perfusion at MPI or <50% coronary stenosis at CCTA were derived in random effect regression analysis, and causes of heterogeneity were determined in meta-regression analysis. We identified 12 eligible articles (6 MPI and 6 CCTA) including 33,129 patients (26,757 in MPI and 6372 in CCTA studies) with suspected CAD. The pooled annualized event rate (AER) for occurrence of hard events (death and nonfatal myocardial infarction) was 1.06 (95% confidence interval, CI 0.49-1.64) in MPI and 0.61 (95% CI 0.35-0.86) in CCTA studies. The pooled NPV was 91% (95% CI 86-96) in MPI and 96 (95% CI 95-98) in CCTA studies. The summary rates between MPI and CCTA were not statistically different. At meta-regression analysis, no significant association between AER and clinical and demographical variables considered was found for overall studies.

CONCLUSIONS

Stress MPI and CCTA have a similar ability to identify low-risk patients with suspected CAD.

Stress/rest myocardial perfusion scintigraphy in patients without significant coronary artery disease

AIM

To define the prognostic impact of stress myocardial perfusion scintigraphy (MPS) in patients with angiographic exclusion of significant coronary artery disease.

METHODS

Angiographic and MPS databases were matched to define patients without significant coronary artery disease by quantitative angiography (diameter stenosis <50%) who underwent stress MPS and coronary angiography within a time period of 3 months. A total of 118 patients were identified and followed for a mean of 6.3 +/- 1.2 years for death, a composite of death, myocardial infarction, bypass surgery, or percutaneous coronary intervention [MAE]) as well as occurrence of symptoms (angina or dyspnoe class CCS II to IV). Stress and rest MPS (using (99m)Tc-MIBI or tetrofosmin) were analyzed by quantitative perfusion SPECT (QPS) for summed stress and rest scores (SSS/SRS).

RESULTS

There were 16 deaths, 29 MAE, and 76 patients with MAE or significant symptoms during follow-up. Significant differences in SSS were found between patients who died (9.5 +/- 6.9 vs. 5.4 +/- 5.6, P = 0.012), had MAE (8.7 +/- 7.2 vs. 5.2 +/- 5.0, P = 0.010), or had MAE or significant clinical symptoms (7.2 +/- 7.1 vs. 4.6 +/- 6.2, P = 0.042) compared to those without the respective event. Logistic regression analysis demonstrated SSS to be a predictor of death (OR = 1.074 [95% CI: 1.004-1.149], P = 0.026) and MAE (OR = 1.087 [95% CI: 1.004-1.181], P = 0.027).

CONCLUSIONS

In patients without significant angiographic coronary artery disease, the result of stress MPS is a predictor of long-term prognosis. Quantitative analysis of MPS allows definition of patients with a higher likelihood to develop clinical events or symptoms.

Stress/Rest Myocardial Perfusion Abnormalities by Gated SPECT: Still the Best Predictor of Cardiac Events in Stable Ischemic Heart Disease

The prognostic power of myocardial perfusion imaging in patients with ischemic heart disease (IHD) has been demonstrated since planar imaging. We aimed to investigate whether gated SPECT retains this value in current cardiology if compared with a complete diagnostic work-up and with more recent prognostic indicators.

METHODS

We selected from our database a cohort of 676 consecutive inpatients who underwent a complete diagnostic work-up that included gated SPECT and coronary arteriography for known or suspected IHD. Patients with acute myocardial infarction (MI), previous coronary artery bypass surgery, or overt hyperthyroidism and patients who were undergoing dialysis treatment were excluded. During follow-up (median, 37 mo), 24 patients died from cardiac causes and 19 experienced a nonfatal MI.

RESULTS

The following were determined to be independent predictors of event-free survival (cardiac death and nonfatal MI) in the different phases of diagnostic work-up using Cox proportional hazards regression analysis: among clinical variables, a previous MI; among laboratory examinations, serum creatinine and low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol levels; among electrocardiographic and echocardiographic variables, left ventricular ejection fraction; and among SPECT variables, summed rest score (SRS) and summed difference score (SDS). In addition, a score of coronary stenoses at angiography was an independent predictor. When the above predictors were tested together, SRS (P < 0.0001), SDS (P = 0.0108), and serum creatinine (P = 0.0186) and LDL and HDL cholesterol levels (P = 0.0222) were the final independent predictors of event-free survival. When gated SPECT was added to the clinical, laboratory, electrocardiographic, and echocardiographic variables, the prognostic stratification significantly improved (P < 0.05); when coronary arteriography was added to gated SPECT, prognostic stratification did not further improve (P > 0.25). If the information provided by gated SPECT was made available after clinical, laboratory, electrocardiographic, echocardiographic, and angiographic variables, the prognostic stratification still improved significantly (P < 0.05). In 492 of these patients with ascertained IHD, SRS and SDS were the final independent predictors of survival. Medical treatment and coronary revascularization did not affect the prognostic information of gated SPECT.

CONCLUSION

Myocardial perfusion abnormalities at rest and after stress are still the best predictors of cardiac event-free survival in patients with known or suspected IHD, even when compared with an extensive diagnostic work-up.

Prognostic significance of stress myocardial gated SPECT among Japanese patients referred for coronary angiography: A study of data from the J-ACCESS database

PURPOSE

The J-ACCESS [Japanese investigation of prognosis based on gated single photon emission computed tomography (SPECT)] study found that quantitative gated myocardial SPECT (QGS) is valuable for predicting the prognosis of Japanese patients with known or suspected ischaemic heart disease. The present study evaluates the incremental prognostic value of myocardial perfusion imaging (MPI) with QGS among patients referred for coronary angiography (CAG).

METHODS

Among 4,031 Japanese patients registered at 117 hospitals for the J-ACCESS study, we selected 1,011 who underwent CAG within 3 months before or after MPI with QGS. Summed stress, rest and difference scores (SSS, SRS and SDS) were generated from myocardial perfusion images using a 20-segment scoring system. Myocardial ischaemia was judged visually. End-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) were determined by QGS. Numbers of diseased (> 75% stenosis) coronary vessels (CDV) were assessed by CAG. All patients were followed up for 3 years to determine cardiac events (CE) including cardiac death, non-fatal myocardial infarction and severe heart failure. Univariate and multivariate analyses of prognostic ability included age, cardiac risk factors (hypertension, hyperlipidaemia, diabetes mellitus and prior myocardial infarction), angiographic findings and the QGS parameters as independent variables.

RESULTS

Cardiac events occurred more frequently with increasing numbers of coronary vessel lesions (p = 0.0016). Cox univariate analysis revealed that diabetes, CDV, SSS, SDS, EDV, ESV and EF were significant predictors (Wald chi(2) = 5.99, 12.9, 8.39, 9.11, 35.5, 42.1 and 31.1, respectively), whereas multivariate analysis selected only ESV and SDS as significant predictors (Wald chi(2) = 36.4, 8.4; p = 0.0038, p < 0.001).

CONCLUSION

MPI with QGS, especially with gated functional data, has incremental prognostic value in addition to angiographic findings. MPI with QGS findings predominantly contribute to the prediction of prognosis rather than numbers of diseased vessels assessed by CAG. Thus, MPI with QGS is the most useful tool with which to guide decisions regarding therapy even among patients referred for CAG.

Comparison of SSS and SRS calculated from normal databases provided by QPS and 4D-MSPECT manufacturers and from identical institutional normals

PURPOSE

There is proven evidence for the importance of myocardial perfusion-single-photon emission computed tomography (SPECT) with computerised determination of summed stress and rest scores (SSS/SRS) for the diagnosis of coronary artery disease (CAD). SSS and SRS can thereby be calculated semi-quantitatively using a 20-segment model by comparing tracer-uptake with values from normal databases (NDB). Four severity-degrees for SSS and SRS are normally used: <4, 4-8, 9-13, and > or =14. Manufacturers' NDBs (M-NDBs) often do not fit the institutional (I) settings. Therefore, this study compared SSS and SRS obtained with the algorithms Quantitative Perfusion SPECT (QPS) and 4D-MSPECT using M-NDB and I-NDB.

METHODS

I-NDBs were obtained using QPS and 4D-MSPECT from exercise stress data (450 MBq (99m)Tc-tetrofosmin, triple-head-camera, 30 s/view, 20 views/head) from 36 men with a low post-stress test CAD probability and visually normal SPECT findings. Patient group was 60 men showing the entire CAD-spectrum referred for routine perfusion-SPECT. Stress/rest results of automatic quantification of the 60 patients were compared to M-NDB and I-NDB. After reclassifying SSS/SRS into the four severity degrees, kappa values were calculated to objectify agreement.

RESULTS

Mean values (vs M-NDB) were 9.4 +/- 10.3 (SSS) and 5.8 +/- 9.7 (SRS) for QPS and 8.2 +/- 8.7 (SSS) and 6.2 +/- 7.8 (SRS) for 4D-MSPECT. Thirty seven of sixty SSS classifications (kappa = 0.462) and 40/60 SRS classifications (kappa = 0.457) agreed. Compared to I-NDB, mean values were 10.2 +/- 11.6 (SSS) and 6.5 +/- 10.4 (SRS) for QPS and 9.2 +/- 9.3 (SSS) and 7.2 +/- 8.6 (SRS) for 4D-MSPECT. Forty four of sixty patients agreed in SSS and SRS (kappa = 0.621 resp. 0.58).

CONCLUSION

Considerable differences between SSS/SRS obtained with QPS and 4D-MSPECT were found when using M-NDB. Even using identical patients and identical I-NDB, the algorithms still gave substantial different results.