Noninvasive assessment of patients undergoing percutaneous intervention in myocardial infarction

Restenosis after primary percutaneous coronary intervention (PPCI) remains an important clinical problem, even with stent implantation. The ability of noninvasive testing to diagnose restenosis has had only inconsistent demonstration.

Our objective was to evaluate the ability of exercise treadmill testing (ETT) and myocardial perfusion imaging (MPI) to diagnose restenosis in patients treated by PPCI within 12 hours of ST-elevation myocardial infarction (STEMI).

From August 2003 to January 2006, 64 patients (mean age of 56.2±10.2 years, 53 males) were enrolled after PPCI. Only patients with left ventricular ejection fraction (LVEF) > 40%, as assessed by resting transthoracic echocardiography (TTE), were included. ETT with 12-lead ECG monitoring and right precordial leads, as also MPI were performed at 6 weeks, 6 months, and one year after intervention. Coronary angiography was performed at six months.

Single-vessel disease was observed in 46.9% of the patients. The left anterior descending coronary artery was treated in 48.4% of the patients. Angiographic restenosis occurred in 28.8%. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of ETT in detecting restenosis were not significant. Right precordial leads did not add information. MPI sensitivity, specificity, PPV, NPV, and accuracy correlated with restenosis only in the 6-month follow-up, both when considering summed difference score >2 (p=0.006) and >4 (p=0.014).

ETT did not discriminate restenosis in this population. MPI performed at 6 months correlated with restenosis and proved useful during follow-up.