Impact of appropriate use on the prognostic value of single-photon emission computed tomography myocardial perfusion imaging.

BACKGROUND: Appropriate use criteria (AUC) have been developed to aid in the optimal use of single-photon emission computed tomography (SPECT)-myocardial perfusion imaging (MPI), a technique that is a mainstay of risk assessment for ischemic heart disease. The impact of appropriate use on the prognostic value of SPECT-MPI is unknown. METHODS AND RESULTS: A prospective cohort study of 1511 consecutive patients undergoing outpatient, community-based SPECT-MPI was conducted. Subjects were stratified on the basis of the 2009 AUC for SPECT-MPI into an appropriate or uncertain appropriateness group and an inappropriate group. Patients were prospectively followed up for 27±10 months for major adverse cardiac events of death, death or myocardial infarction, and cardiac death or myocardial infarction. In the entire cohort, the 167 subjects (11%) with an abnormal scan experienced significantly higher rates of major adverse cardiac events and coronary revascularization than those with normal MPI. Among the 823 subjects (54.5%) whose MPIs were classified as appropriate (779, 51.6%) or uncertain (44, 2.9%), an abnormal scan predicted a multifold increase in the rates of death (9.2% versus 2.6%; hazard ratio, 3.1; P=0.004), death or myocardial infarction (11.8% versus 3.3%; hazard ratio, 3.3; P=0.001), cardiac death or myocardial infarction (6.7% versus 1.7%; hazard ratio, 3.7; P=0.006), and revascularization (24.7% versus 2.7%; hazard ratio, 11.4; P<0.001). Among the 688 subjects (45.5%) with MPI classified as inappropriate, an abnormal MPI failed to predict major adverse cardiac events, although it was associated with a high revascularization rate. Furthermore, appropriate MPI use provided incremental prognostic value beyond myocardial perfusion and ejection fraction data. CONCLUSIONS: When performed for appropriate indications, SPECT-MPI continues to demonstrate high prognostic value. However, inappropriate use lacks effectiveness for risk stratification, further emphasizing the need for optimal patient selection for cardiac testing.

The prognostic value of cardiac SPECT performed at the primary care physician's office.

BACKGROUND: The prognostic value of single-photon emission computed-tomography (SPECT)-myocardial perfusion imaging (MPI) is well documented. However, the utility of SPECT-MPI when performed at a low-volume primary care physician's (PCP's) office is unknown. METHODS: We conducted a prospective cohort study of consecutive patients referred by their PCP to undergo a stress-MPI at the PCP's office using a mobile laboratory. Major adverse cardiovascular events (MACE) of death, myocardial infarction (MI), and coronary revascularization were prospectively tabulated using mail and telephone interviews, chart review, and social security death index. RESULTS: One thousand three hundred ninety subjects [mean age 58 ± 13 years; 44% women] were followed for 27 ± 9 months, with a 99% complete follow-up rate. Subjects with abnormal MPI [174 (12.5%)] had significantly higher rates of all-cause mortality [5.2% vs 1.0%, P < .001], death, or MI [5.7% vs 1.5%, P = .001], and the composite of death, MI, or late revascularization (>60 days post-MPI) [12.6 vs 2.7%, P < .001]. Overall MACE risk was associated with the total perfusion abnormality burden, while the revascularization rate was related to the reversible perfusion abnormality burden. CONCLUSION: Contemporary SPECT-MPI performed in the setting of a PCP's office carries a robust prognostic value, similar to that reported in tertiary or large-volume practice settings.

Age and gender as predictors of benefit from aminophylline administration in patients undergoing regadenoson stress myocardial perfusion imaging: a substudy of the ASSUAGE trial.

Regadenoson is a selective adenosine A2A-receptor agonist, used as a pharmacological stress agent for myocardial perfusion imaging. It is associated with frequent adverse effects (AEs), particularly among individuals younger than 65 years of age and women. Intravenous aminophylline administration following regadenoson, as described in the ASSUAGE trial, reduces the incidence of AE. In this substudy of the ASSUAGE trial, we compared the absolute and relative benefits of aminophylline administration versus placebo, between subgroups of age (<65 vs. ≥65 years) and gender (women vs. men). Study endpoints were headache, gastrointestinal AE, any regadenoson AE, and tolerability (feeling comfortable during regadenoson stress). Among patients <65years, compared with ≥65 years, aminophylline administration was associated with greater absolute risk reduction (ARR) in gastrointestinal AE (16% vs. 5%, P = 0.01) and any regadenoson AE (31% vs. 12%, P = 0.001), and with a greater absolute improvement in tolerability (21% vs. 1%, P < 0.001). Men received greater ARR in gastrointestinal AE than women (18% vs. 2%, P < 0.001). There was no difference in the ARR in other AE between subgroups. Across all subgroups, aminophylline use was associated with a consistent trend toward relative reduction in AE rates and improved tolerability. No significant interaction was identified between subgroups and aminophylline administration in reducing AE. In conclusion, although aminophylline use was associated with greater ARR in AE in certain subgroups, a consistent benefit with aminophylline administration was attained in all subgroups. Thus, to predictably reduce regadenoson AE and improve tolerability, aminophylline should be administered routinely to all patients as per the ASSUAGE protocol.

Predicting short-term adverse outcomes in the geriatric population presenting with syncope: a comparison of existing syncope rules and beyond.

OBJECTIVES: Syncope at age 65+ is associated with increased mortality, irrespective of cause. Syncope rules were designed to aid in risk-stratification but were only validated in the general adult population. Our objective was to determine if they can be applied to a geriatric population in predicting short-term adverse outcomes. METHODS: In this single-center retrospective study, we evaluated 350 patients aged 65+ presenting with syncope. Exclusion criteria included confirmed non-syncope, active medical condition, drug or alcohol-related syncope. Patients were stratified into high or low risk based on Canadian Syncope Risk Score (CSRS), Evaluation of Guidelines in Syncope Study (EGSYS), San Francisco Syncope Rule (SFSR), and Risk Stratification of Syncope in the Emergency Department (ROSE). Composite adverse outcomes at 48-hour and 30-day included all-cause mortality, major adverse cardiac and cerebrovascular events (MACCE), return emergency department visit, hospitalization, or medical intervention. We assessed each score's ability to predict the outcomes using logistic-regression and compared performances using receiver-operator curves. Multivariate analyses were performed to study the associations between recorded parameters and outcomes. RESULTS: CSRS outperformed with AUC of 0.732 (95% CI: 0.653-0.812) and 0.749 (95% CI: 0.688-0.809) for 48-h and 30-day outcomes, respectively. Sensitivities for CSRS, EGSYS, SFSR, and ROSE for 48-hour outcomes were 48%, 65%, 42% and 19%; and for 30-day outcomes were 72%, 65%, 30% and 55%, respectively. Atrial fibrillation/flutter on EKG, congestive heart failure, antiarrhythmics, systolic blood-pressure < 90 at triage, and associated chest pain highly correlated with 48-h outcomes. An EKG abnormality, heart disease history, severe pulmonary hypertension, BNP > 300, vasovagal predisposition, and antidepressants highly correlated with 30-day outcomes. CONCLUSIONS: Performance and accuracy of four prominent syncope rules were suboptimal in identifying high-risk geriatric patients with short-term adverse outcomes. We identified some significant clinical and laboratory information that may play a role in predicting short-term adverse events in a geriatric cohort.