Follow-up of patients with reversible myocardial perfusion defects and hemodynamically non-significant lesions on coronary angiography

Abstract

Background: The prognostic value of stress-rest myocardial perfusion imaging (MPI) has been extensively studied in patients with hemodynamically significant coronary lesions. Few studies have explored the predictive value of reversible defects (RD) in patients with normal or near-normal coronary angiography (CA). We sought to examine the cardiac outcome in this group of patients were MPI is considered false positive. Methods: Our study group consisted of 52 patients (37 males) with suspected CAD, mean age 50 ± 9, having CA described as either normal (40%), minor lesions (10%-50% stenosis) (54%) and intermediate lesions (50%-70% stenosis) (6%). Each patient had at least one RD on MPI performed 4.9 ± 4.5 months from CA. SPECT MPI was performed with 99m-Tc Sestamibi (18), Thallium-201 (31) or dual isotope (1). Treadmill exercise was used in 36 and pharmacologic stress in 16 patients. Summed difference score (SDS), defined as the difference between the summed stress and rest perfusion scores on a 9-segment 4-point (0–3) model (Min/Max score: 0/27), identified RD as stress-induced ischemia. Studies considered difficult to interpret (TDS) due to technical artefacts were reported as such. Patients were followed for 47 ± 27 months (min 13, max 85). Results: During follow-up, 5 (10%) patients suffered cardiac events: 2 underwent CABG (1 male and 1 female, 13 and 4 months after MPI), 1 fatal myocardial infarction (male, 7 months after MPI), 2 were diagnosed with cardiomyopathy (1 male and 1 female, 25 and 26 months after MPI). On initial CA, all the three patients developing CAD had only minor lesions (20–30% range), while those developing cardiomyopathy had normal coronaries. SDS was higher in the patients with events (2.8 ± 1.1) than in those without (2.6 ± 1.9), but this difference was not statistically significant. TDS represented 12 (26%) in the non-event group. No patients in the event-group had TDS. Conclusion: Reversible defects on MPI may identify a patients at risk for future cardiac events even in the presence of normal or near-normal coronary angiography.