The prognostic value of estimating stroke volume before and after
exercise during treadmill stress echocardiography
Background: Stress echocardiography (SE) is an established technique for
assessment of coronary artery disease (CAD) which is difficult to
perform and interpret. Left ventricular stroke volume (SV) is readily
estimated with Doppler echocardiography. It can be affected by
myocardial ischemia, with possible adjunctive value during SE. Methods:
Patients underwent Bruce protocol SE with SV estimated before and after
maximal treadmill exertion post routine regional wall analysis.
Incremental change in SV (ΔSV) with exercise was measured. Results: A
derivation cohort (n=273) was established to test the hypothesis. An
optimal cut-off for detection on inducible ischemia was ΔSV ≤ +10ml. The
validation cohort of consecutive patients (n = 1093, 376 [34%]
female; age 59±12 years) were followed clinically after SE for 20,460
patient-months. There were 1000 patients with non-ischemic SE, and 93
patients with studies suggestive of myocardial ischemia. Secondary
analysis yielded 831 patients with a normal exercise response (ΔSV
> +10ml) and 192 with an abnormal ΔSV ≤ +10ml. Time to
first combined adverse cardiac event (composite of angina, acute
coronary syndrome, cardiac revascularization, worsening New York Heart
Association (NYHA) class, a reduction in EF, and cardiovascular death)
was analysed and adjusted using Cox proportional hazards regression. The
hazard ratio for an adverse event with an abnormal ΔSV response (≤10ml)
was 10.3 (95% confidence intervals 5.6-19.1, p<0.0001).
Conclusions: SV assessment during SE is feasible and readily performed.
It is simple, practical and has incremental diagnostic and prognostic
value when added to exercise regional wall motion analysis.