Quantitative Gated Single-Photon Emission Computed Tomography With 99mTc Sestamibi Predicts Major Cardiac Events in Elderly Patients With Known or Suspected Coronary Artery Disease The QGS-Prognostic Value in the Elderly (Q-PROVE) Study

Prediction of 14-year cardiovascular outcomes by dobutamine stress 99mTc-tetrofosmin myocardial perfusion SPECT in elderly patients unable to perform exercise testing

BACKGROUND

Dobutamine stress myocardial perfusion imaging (MPI) is a useful alternative for the evaluation of coronary artery disease (CAD) in elderly patients who are unable to perform an exercise stress test. However, data on the long-term prognostic value of stress MPI in elderly patients are lacking. Therefore, this study evaluated the long-term prognostic value of dobutamine stress MPI in elderly patients unable to perform an exercise test.

METHODS

The study population consisted of 247 elderly patients (mean age 71 ± 5 years) who underwent dobutamine stress single-photon emission computed tomography (SPECT) MPI. An abnormal SPECT study was defined as the presence of fixed and/or reversible perfusion defects. A summed stress score (SSS) was obtained to estimate the extent and severity of perfusion defects. End points during follow-up were all-cause mortality, cardiac mortality, and nonfatal myocardial infarction (MI).

RESULTS

During a median follow-up of 14 years (range 12-16), 168 (68%) patients died (all-cause mortality), of which 56 (23%) were due to cardiac causes. Nonfatal MI occurred in 19 (8%) patients. Kaplan-Meier survival curves showed that MPI provided optimal risk stratification in patients with normal and abnormal MPI. Multivariable analysis identified an abnormal MPI as a strong significant predictor of all-cause mortality and cardiac events. A multivariable analysis also revealed that a reversible defect and SSS were strong long-term predictors of cardiac mortality and hard cardiac events.

CONCLUSION

Dobutamine stress 99mTc-tetrofosmin SPECT provides incremental prognostic information for the prediction of long-term cardiovascular outcomes in elderly patients, unable to perform exercise testing. Dobutamine stress MPI is useful in risk classifying elderly patients.

Predictive value of exercise myocardial perfusion imaging in the Medicare population: the impact of the ability to exercise

BACKGROUND

Although the prognostic value of quantitative single photon emission computed tomography myocardial perfusion imaging (MPI) with exercise and pharmacologic stress is well established, the prognostic and management value in the Medicare age population is less clear.

METHODS

The prospectively populated Cleveland Clinic nuclear cardiology database was used to identify 5,994 consecutive pateints, age >65 years [1,664 (28%) exercise MPI, mean age 72.4±5.1, 74% male], who underwent MPI between January 2004 and January 2008. Clinical baseline variables, post test 90 days revascularization and MPI variables were analyzed. Overall and stratified nonparametric survival estimates were obtained by Kaplan-Meier method. Median follow-up time was 2.4 years. Parametric hazard modeling with bootstrap bagging methods was used to determine prognostic variables predicting mortality.

RESULTS

There was no difference in mortality in patients with an abnormal MPI vs. those with normal MPI. Amongst the patients who underwent exercise MPI, there were 103 (6%) deaths and 121 (8.2%) revascularizations. Only lower exercise capacity (<7 METs) and higher end systolic volume (ESV) predicted mortality. Although a larger amount of ischemia influenced down stream revascularization ischemia, revascularization of patients with an abnormal exercise MPI did not offer a survival benefit (log rank P value=0.01).

CONCLUSIONS

In the a Medicare age population, exercise MPI perfusion variables influenced rates of revascularization but failed to provide incremental significant risk-stratification beyond exercise capacity. Maximum METs achieved appears to be a better predictor of survival.

Cardiac event risk in Japanese subjects estimated using gated myocardial perfusion imaging, in conjunction with diabetes mellitus and chronic kidney disease

BACKGROUND

Cardiac event risk is estimated using quantitative gated myocardial perfusion imaging (MPI) and clinical background in patients with ischemic heart disease. The aim of the present study was to calculate major cardiac event risk and tabulate it in the Heart Risk Table for clinical use of risk stratification.

METHODS AND RESULTS

Multivariate logistic regression was performed based on a multicenter prognostic database (Japanese Assessment of Cardiac Events and Survival Study by Quantitative Gated Single-photon emission computed tomography [J-ACCESS investigation]) using MPI (n=2,395). The risk of major cardiac events (cardiac death, non-fatal myocardial infarction and heart failure requiring hospitalization) was estimated using age, ejection fraction (EF), estimated glomerular filtration rate (eGFR) and presence of diabetes mellitus (DM). Age-matched standard eGFR was determined in 77 subjects. Major cardiac event risk was calculated using the equation: risk (%/3 years)=1/(1+Exp(-(-4.699-0.0151×eGFR+0.7998×DM+0.0582×age+0.697×SSS-0.0359×EF))×100, where SSS refers to summed stress scores. Risk was determined without eGFR (the initial version) and using the present formula with eGFR (revised version), with consistent results. DM and chronic kidney disease were major determinants of cardiac events.

CONCLUSIONS

Cardiac event risk was estimated using MPI defect score and left ventricular EF in conjunction with eGFR and the presence of DM. The risk table might be used for risk evaluation in Japanese patients undergoing MPI.

Prognostic role of myocardial single photon emission computed tomography in the elderly

The increase in average life expectancy will move the burden of coronary artery disease (CAD) to older patients. Myocardial perfusion imaging by single photon emission computed tomography (SPECT) has been extensively validated for diagnosis and prognostic evaluation in large population series. Yet, its use is usually limited in elderly patients in whom, despite increased absolute cardiovascular risk, diagnostic and therapeutic work-up is often underperformed. American College of Cardiology/American Heart Association guidelines recommend exercise ECG testing as the initial noninvasive method for assessment of CAD in patients with a normal or near-normal resting ECG, regardless of age. However, a considerable proportion of elderly patients is unable to reach an adequate workload during the exercise test and the majority of those undergoing for standard exercise treadmill score are classified as intermediate risk. In elderly patients, SPECT imaging may provide valuable diagnostic and prognostic information for clinical management. In particular, normal or near normal SPECT identifies elderly patients at low risk of major adverse cardiac events at the short-term follow-up.

[Management of ischemic heart disease in the elderly]

Clinical features of ischemic heart disease in the elderly are different from those in non-elderly patients. The prevalence of female patients, hypertension and co-morbidity was higher in the elderly than in non-elderly patients. Atypical clinical presentation should be taken into consideration, particularly in patients with acute coronary syndrome, because early initiation of coronary reperfusion therapy reduces mortality significantly in elderly patients. In chronic stable angina, risk stratification of patients using stress myocardial perfusion imaging plays an important clinical role. The management of coronary risk factors to prevent cardiovascular events is of utmost importance in the elderly since the mortality of acute myocardial infarction is very high. Among classical risk factors, beneficial effects of the management of blood pressure on hypertensive and/or diabetic patients are enormous. Recent development of percutaneous coronary intervention facilitated coronary revascularization to reduce ischemic burden even in patients aged 80 years or older due to the low invasiveness of the procedure. However, cardiac surgery is still regarded as the first option for the elderly ith associated aortic stenosis, diffuse 3-vessel coronary artery disease, or distal left main trunk disease.

Comparative impact of scintigraphic parameters and B-type natriuretic peptide for the prediction of major cardiac events in the QGS-prognostic value in the elderly (Q-PROVE) study

BACKGROUND

Although B-type natriuretic peptide (BNP) has emerged as an important predictor for cardiac events, its effect on scintigraphic parameters is unknown.

METHODS AND RESULTS

The Q-PROVE study is a multicenter study to evaluate the prognostic value of ECG-gated SPECT in 175 Japanese elderly patients. In addition, BNP was assessed in 102 patients. Outcome assessment included cardiac events and noncardiac deaths. Twelve elderly patients (12%) had increased BNP >130 pg/ml. The summed stress score (SSS) was greater in patients with increased BNP than in those with normal BNP. Kaplan-Meier survival estimation indicated event-free survival rates at 3 years of 83%, 78%, 88%, 80%, respectively, in patients with BNP >130 pg/ml, SSS >or=7, summed difference score (SDS) >or=2, and dilated end-diastolic volume (EDV), but 98%, 98%, 100%, 94% in those with BNP <or=130 pg/ml, SSS <7, SDS <2 and normal EDV (P=0.006, P=0.005, P=0.0008, P=0.01). Multivariate analysis demonstrated that an SDS was the only independent predictor for subsequent cardiac events (hazard ratio =4.0, P=0.04).

CONCLUSIONS

Although BNP may have similar prognostic value to gated SPECT volumetric measurements in elderly patients with known or suspected coronary artery disease, myocardial ischemia as documented by SPECT is still indispensable for detecting high-risk patients compared with BNP alone.

Isolated single coronary artery: a series of 10 cases

BACKGROUND

Isolated single coronary artery (SCA) is an extremely rare congenital coronary anomaly. Some subgroups of SCA can lead to angina pectoris, acute myocardial infarction or even sudden death in the absence of atherosclerosis. Young patients, especially, have the risk of serious clinical events, but middle-aged-to elderly patients have a variable clinical course.

METHODS AND RESULTS

The aim of this study was to present the clinical and angiographic properties, relatively long-term follow-up (54+/-14 months) and management of adult patients (mean age 57+/-12 years) with SCA. The records of 70,850 patients undergoing coronary angiography between 1999 and 2005 were reviewed. Ten patients (0.024%) were found to have SCA, originating from the left sinus of Valsalva in 3 (30%) patients and from the right sinus of Valsalva in 7 patients (70%). No atherosclerotic involvement was seen in 7 (70%) patients. One patient was also treated by stent implantation to the SCA. Other patients were followed medically. All patients have been followed uneventfully.

CONCLUSION

Medical treatment is usually adequate for middle-aged to elderly patients with SCA in the absence of ischemia and/or acute coronary syndrome.

Differential effects comparing exercise and pharmacologic stress on left ventricular function using gated Tc-99m sestamibi SPECT

OBJECTIVE

Although post-ischemic stunning has emerged as an important marker for severe coronary artery disease (CAD), differences in stress methods may have different effects on left ventricular (LV) volumes and function.

METHODS

To assess differential effects comparing exercise and pharmacologic stress on the LV measurements, (99m)Tc-sestamibi gated single-photon emission computed tomography (SPECT) acquired more than 30 min after stress and at rest was evaluated in 38 patients undergoing adenosine triphosphate (ATP) stress (ATP group) and 38 age-and sex-matched patients subjected to exercise stress (Ex group) among 268 patients with normal SPECT findings.

RESULTS

Coronary risk factors and LV volumetric measurements at baseline were similar in the two groups. Compared with volumetric measurements at rest, end-diastolic volume (EDV) increased (72 +/- 21 ml to 74 +/- 21 ml; P = 0.01), end-systolic volume increased (25 +/- 12 ml to 28 +/- 13 ml; P = 0.001), and ejection fraction (EF) decreased after stress (66% +/- 8% to 63% +/- 9%; P < 0.002) in the ATP group. In the Ex group, by contrast, no such change was observed. In addition, changes in EDV (3 +/- 6 vs. -1 +/- 5 ml; P = 0.01) and the stress-to-rest ratio of EDV (1.04 +/- 0.09 vs. 0.99 +/- 0.08; P < 0.02) after stress were greater in the ATP than in the Ex group.

CONCLUSIONS

Differential effects of stress methods on LV volumes persist more than 30 min after the stress. These findings should be kept in mind when interpreting post-ischemic stunning.