Hemodynamic variables during stress testing can predict referral to early catheterization but failed to show a prognostic impact on emerging cardiac events in patients aged 70 years and older undergoing exercise (99m)Tc-sestamibi myocardial perfusion scintigraphy

Clinical implications of referral bias in the diagnostic performance of exercise testing for coronary artery disease

BACKGROUND

Exercise testing with echocardiography or myocardial perfusion imaging is widely used to risk-stratify patients with suspected coronary artery disease. However, reports of diagnostic performance rarely adjust for referral bias, and this practice may adversely influence patient care. Therefore, we evaluated the potential impact of referral bias on diagnostic effectiveness and clinical decision-making.

METHODS AND RESULTS

Searching PubMed and EMBASE (1990-2012), 2 investigators independently evaluated eligibility and abstracted data on study characteristics and referral patterns. Diagnostic performance reported in 4 previously published meta-analyses of exercise echocardiography and myocardial perfusion imaging was adjusted using pooled referral rates and Bayesian methods. Twenty-one studies reported referral patterns in 49 006 patients (mean age 60.7 years, 39.6% women, and 0.8% prior history of myocardial infarction). Catheterization referral rates after normal and abnormal exercise tests were 4.0% (95% CI, 2.9% to 5.0%) and 42.5% (36.2% to 48.9%), respectively, with odds ratio for referral after an abnormal test of 14.6 (10.7 to 19.9). After adjustment for referral, exercise echocardiography sensitivity fell from 84% (80% to 89%) to 34% (27% to 41%), and specificity rose from 77% (69% to 86%) to 99% (99% to 100%). Similarly, exercise myocardial perfusion imaging sensitivity fell from 85% (81% to 88%) to 38% (31% to 44%), and specificity rose from 69% (61% to 78%) to 99% (99% to 100%). Summary receiver operating curve analysis demonstrated only modest changes in overall discriminatory power but adjusting for referral increased positive-predictive value and reduced negative-predictive value.

CONCLUSIONS

Exercise echocardiography and myocardial perfusion imaging are considerably less sensitive and more specific for coronary artery disease after adjustment for referral. Given these findings, future work should assess the comparative ability of these and other tests to rule-in versus rule-out coronary artery disease.

Pathological 99mTc-sestamibi myocardial perfusion scintigraphy is independently associated with emerging cardiac events in elderly patients with known or suspected coronary artery disease

BACKGROUND

Only few data are available regarding the prognostic impact of myocardial perfusion scintigraphy with (99m)Tc-sestamibi (MPS) regarding emerging cardiac events in elderly patients

PURPOSE

To evaluate the prognostic value of MPS regarding emerging cardiac events in patients aged ≥70 years with known or suspected coronary artery disease (CAD).

MATERIAL AND METHODS

One hundred and thirty-three patients (74.6 ± 3.7 years) who underwent exercise or pharmacological stress/rest MPS were included in this analysis. Semi-quantitative visual interpretation of MPS images was performed and Summed-Stress- (SSS), Summed-Difference- (SDS), and Summed-Rest Scores (SRS) were calculated. Multivariate logistic regression analyses were calculated for evaluation of the independent prognostic impact of MPS results and several cardiac-related patient characteristics with regard to emerging cardiac events. Kaplan-Meier survival- and log rank analyses were calculated for assessment of cardiac event-free survival.

RESULTS

Pathological SSS (OR: 3.3), angina (OR: 2.7) and ischemic ECG (OR: 3.0) were independently associated with cardiac events. Patients with pathological SSS (p=0.005) and ischemic ECG (p=0.012) had a significantly lower incidence of cardiac event-free survival.

CONCLUSION

Pathological MPS is independently associated with emerging cardiac events predicting a significantly lower incidence of cardiac event-free survival in patients aged ≥70 years.