Abstract 15316: Dobutamine Stress Echocardiography (DSE) Allows Assessment of Pressure-Flow Relationships in the Pulmonary Circulation in Health and Disease
Background: Assessing pulmonary pressure-flow (PPA-Q) relationships under stress is likely to reveal earlier stages of pulmonary vascular disease (PVD) than assessments made at rest. A reproducible non-invasive modality for assessing PPA-Q relations is thus desirable, especially as echocardiographic measurements during exercise are technically challenging.
Methods: We used Dobutamine Stress Echo (DSE) to generate PPA-Q plots in 38 subjects (n=22 Healthy Controls; n=16 patients with PVD) (peak dobutamine dose 20 mcg.kg-1.min-1). All PVD patients had mean PPA > 25 mmHg and PVR > 3 Wood Units. Matched healthy controls (n=22) underwent exercise echocardioraphy as a comparator. PPA was estimated from peak Tricuspid Regurgitant velocity; and Q from LV outflow velocity time integral. PA distensibility coefficient α was calculated by fitting a curvilinear model.
Results: ControlsDSE (age 46 ± 16 yrs, 12 males) and PVDDSE (age 56 ± 9 yrs, 4 males) achieved similar peak dobutamine dose (19.8 ± 1.1 vs. 18.4 ± 3.0 mcg.kg-1.min-1) with an average of 4.7 ± 0.5 data points per subject. The average slope of PPA-Q relations in ControlsDSE was 1.1 ± 0.7 mmHg.min.L-1 with an intercept of 10.4 ± 3.9 mmHg. In PVDDSE, average slope was 5.1 ± 2.5 mmHg.min.L-1 with an intercept of 27.6 ± 13.8 mmHg (p < 0.001 compared to ControlsDSE)(see Figure). Coefficient α was markedly reduced in PAHDSE, (0.003 ± 0.001 vs. 0.02 ± 0.01 mmHg-1 in ControlsDSE, p < 0.001). In healthy controls, exercise was associated with a higher PPA-Q slope (1.6 ± 0.7 mmHg.min.L-1) and lower intercept (7.6 ± 4.2 mmHg) compared to dobutamine stress (p < 0.05).
Conclusions: Non-invasive assessment of PPA-Q relationships is feasible with DSE, with marked differences shown between controls and PVD patients. Exercise is associated with a higher PPA-Q slope in healthy controls, potentially related to dobutamine-induced vasodilatation. DSE may be a valuable non-invasive technique for assessing the pulmonary vasculature.
- © 2013 by American Heart Association, Inc.