Abstract
Background
Coronary flow velocity reserve (CFVR) of left anterior descending artery is useful for risk stratification during stress echocardiography (SE) as an add-on to regional wall motion abnormalities (RWMA), but the age-and sex-dependence of prognostic cutoff values remains unclear.
Purpose
To provide sex and age-specific prognostic cut-off values which may be needed to account for the physiologic decline of CFVR with age, and sex-related differences in resting flow.
Methods
In an observational, prospective, multicenter, registry study design, we enrolled from August 2003 to August 2017 in 4 Italian cardiology referral centers with accredited, quality-controlled stress echo laboratory a consecutive sample of 5,577 patients (of them, 2,284 women and 110 aged ≥85 years) referred to the SE lab for known or suspected coronary artery disease, after exclusion of patients with inadequate acoustic window (n=295), premature test interruption (n=105), and lost to follow-up (n=173).All underwent dual imaging (RWMA and CFVR) dipyridamole SE (0.84 mg/kg over 6') and were followed-up. All-cause death and non-fatal myocardial infarction were the main outcome measures. Median follow-up of 20 months (1st quartile 8, 3rd quartile 43 months),
Results
There were 649 hard events (236 deaths and 413 non-fatal myocardial infarctions), 288 of which occurred in women and 38 in patients ≥85 years. With a ROC analysis, the best prognostic cut-off value for CFVR was almost the same for men (2.03) and women (2.02) and consistent across all age strata (<45 years: 2.03; 45–54 years: 2.04; 45–64 years: 2.03; 65–74 and 75–84 years: 2.0) except for the very elderly (>85 years) who showed an optimal value of 1.90. Independent prognostic indicators were RWMA (HR=5.42, 95% CI=2.42–12.15; p<0.0001) and reduced CFVR (HR=3.26, 95% CI 2.27–3.90; p<0.0001) in patients aged <85 years, and RWMA (HR=5.42, 95% CI=2.42–12.15; p<0.0001) in patients aged >85 years.
Best prognostic cut-off value of CFVR
Conclusion
A sex-independent cut-off value of CFVR ≤2.0 provides the optimal risk stratification across all age groups, except those >85 years in whom a lower cut-off <1.90 is needed. Risk stratification is more effective for all age groups when CFVR is combined with RWMA.
Coronary Flow Velocity Reserve in Stress Echocardiography
