[Analysis of the number of patients needed to treat by coronary revascularisation in relation to the presence of myocardial viability in gated SPECT images: a prospective cohort study from a nuclear cardiology unit].

OBJECTIVE: To evaluate the number of patients needed to treat (NNT) to assess the magnitude of benefit of coronary revascularisation (CR) in patients with ischaemic cardiomyopathy (IC) in relation to the presence or absence of myocardial viability in myocardial perfusion gated-SPECT (single photon emission computed tomography) images.

METHOD: We studied 198 consecutive patients with IC using rest gated-SPECT with technetium-based agents. The cardiac mortality was analysed in four groups: viable with CR (n = 50), viable with medical treatment (MT) (n = 90), non-viable with CR (n = 18), and non-viable with medical treatment (n = 40).

RESULTS: During 2.3 +/- 1.2 years of follow-up, the cardiac mortality rate in patients with scintigraphic viability criteria undergoing revascularisation was 5.9/100 patients/year and 12.9/100 patients/year in those who received medical treatment. In patients without viability who underwent revascularisation, the cardiac mortality rate was 6.2/100 patients/year and in those who received MT it was 1.9/100 patients/year. In patients with myocardial viability the NNT was 4, while in patients without myocardial viability, the NNT was 24.

CONCLUSIONS: In patients with scintigraphic viability criteria, the NNT to obtain one survival with CR was 6 times lower with respect to patients without viability, with lower cost and mortality.