ABSTRACT
AIMS: Although pre-revascularization ischaemia testing is recommended, the interaction between the extent of ischaemia and myocardial scar with performance of revascularization on patient survival is unclear. METHODS AND RESULTS: We identified 13 969 patients who underwent adenosine or exercise stress SPECT myocardial perfusion scintigraphy (MPS). The percent myocardium ischaemic (%I) and fixed (%F) were calculated using 5 point/20-segment MPS scoring. Patients lost to follow-up (2.8%) were excluded leaving 13 555 patients [35% with history (Hx) of known coronary artery disease (CAD), 65% exercise stress, 61% male, age 66 ± 12]. Follow-up was performed at 12-18 months for early revascularization and at >7 years for all-cause death (ACD) (mean follow-up 8.7 ± 3.3 years). All-cause death was modelled using Cox proportional hazards modelling adjusting for logistic-based propensity scores, MPS, revascularization, and baseline characteristics. During FU, 3893 ACD (29%, 3.3%/year) and 1226 early revascularizations (9.0%) occurred. After risk-adjustment, a three-way interaction was present between %I, early revascularization, and HxCAD, such that %I identified a survival benefit with early revascularization in patients without prior myocardial infarction (MI), whereas no such benefit was present in patients with prior MI (overall model χ(2)= 3932, P < 0.001; interaction P < 0.021). Further modelling revealed that after excluding patients with scar >10% total myocardium, %I identified a survival benefit in all patients. CONCLUSION: In this large observational series with long-term follow-up, patients with significant ischaemia and without extensive scar were likely to realize a survival benefit from early revascularization. In contrast, the survival of patients with minimal ischaemia was superior with medical therapy without early revascularization.
Subject(s)
Cardiotonic Agents/therapeutic use , Cicatrix/complications , Myocardial Ischemia/therapy , Myocardial Revascularization/methods , Aged , Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography/methods , Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography/mortality , Cicatrix/diagnostic imaging , Cicatrix/mortality , Exercise Test , Female , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Myocardial Ischemia/diagnostic imaging , Myocardial Ischemia/mortality , Myocardial Revascularization/mortality , Propensity Score , Radiopharmaceuticals , Technetium Tc 99m Sestamibi , Tomography, Emission-Computed, Single-Photon/methods , Treatment OutcomeABSTRACT
OBJECTIVE: To assess the value of left ventricular (LV) dyssynchrony, using phase analysis of nuclear single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) as independent predictor of cardiac events. METHODS: Phase analysis using Emory Cardiac Toolbox was applied on gated rest MPI scans to assess LV dyssynchrony in a total of 202 patients. Follow-up was obtained in 197 patients (97.5%). Major adverse cardiac events (MACE) (cardiac death and hospitalisation for any cardiac reasons, including worsening of heart failure, non-fatal myocardial infarction, unstable angina and coronary revascularisation) were determined using the Kaplan-Meier method. Cox proportional hazard regression was used to identify independent predictors of cardiac events. RESULTS: At a median follow-up of 3.2 ± 1.2 years, 41 patients had at least one event, including 5 cardiac deaths. LV dyssynchrony (n = 35) was associated with a significantly higher incidence of MACE (p<0.001) and proved to be an independent predictor of cardiac events. CONCLUSION: LV dyssynchrony assessed by phase analysis of gated SPECT-MPI is a strong predictor of MACE independent of other known predictors such as perfusion defects or decreased LV ejection fraction.
