Prognostic role of stress/rest myocardial perfusion scintigraphy in patients with cardiac syndrome x

Abstract

Aim: The prognostic utility of myocardial perfusion scintigraphy (MPS) in patients with angiographically normal coronary arteries has not been evaluated yet. Our aim was to determine the prognostic role of positive MPS in patients with angina, positive exercise test and smooth coronary arteries (syndrome X).

Methods: A total of 156 patients with angina, positive exercise test, positive MPS and normal coronary arteries and 172 patients with angina and positive exercise test who had negative MPS were selected for study. The primary endpoint was combined all-cause mortality and hospitalizations for cardiac causes. The secondary endpoint was hospitalization for cardiac causes.

Results: Kaplan-Meier analysis showed a greater (p=0.001) incidence of the primary endpoint in patients with positive MPS, compared to those with negative MPS. Additionally, Kaplan-Meier analysis for cardiovascular hospitalization showed a significant difference (p=0.003) between the two groups. Cox regression analysis, adjusted for age, sex, BMI and antianginal therapy confirmed a significant risk increase for patients with positive MPS, with a hazard ratio (HR)=3.20 (CI 95%: 1.14-9.02; p=0.028). Cox analysis for cardiovascular hospitalization also showed a significant risk increase for patients with positive MPS (HR=3.19; CI 95%: 1.13-9.00; p=0.03). Finally, Cox analysis showed that patients with positive MPS tend to have a higher risk to remain symptomatic in the follow-up period (HR=1.614; CI 95%: 0.999-2.607; p=0.51).

Conclusions: This study shows that inducible myocardial hypoperfusion at MPS in patients with syndrome X could discriminate patients with a more severe prognosis, especially in terms of further hospitalization and symptomatic burden.

Keywords: Cardiac syndrome X; Myocardial perfusion scintigraphy; Normal coronary arteries; Prognosis; SPECT.