CHEST
Volume 146, Issue 4, October 2014, Pages 959-966
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Original Research: Pulmonary Vascular Disease
Dobutamine Stress Echocardiography for the Assessment of Pressure-Flow Relationships of the Pulmonary Circulation

https://doi.org/10.1378/chest.13-2300Get rights and content

BACKGROUND

Stress testing of the pulmonary circulation (via increasing pulmonary blood flow) can reveal abnormal mean pulmonary artery pressure-cardiac output (mPpa-Q) responses, which may facilitate early diagnosis of pulmonary vascular disease. We investigated the application of dobutamine stress echocardiography (DSE) for the noninvasive assessment of mPpa-Q relationships.

METHODS

DSE using an incremental dose protocol (≤ 20 μg/kg/min) was performed in 38 subjects (16 patients with pulmonary arterial hypertension [PAH] and 22 healthy control subjects). An additional 22 healthy control subjects underwent exercise stress echocardiography as a comparator group. Multipoint mPpa-Q plots were analyzed, and the pulmonary vascular distensibility coefficient α was calculated.

RESULTS

DSE was feasible and informative in 93% of subjects. The average dobutamine-induced mPpa-Q slope was 1.1 ± 0.7 mm Hg/L/min in healthy control subjects and 5.1 ± 2.5 mm Hg/L/min in patients with PAH (P < .001). The dobutamine-induced α was markedly reduced in patients with PAH (0.003 ± 0.001 mm Hg vs 0.02 ± 0.01 mm Hg in control subjects, P < .001). When exercise and dobutamine stress were compared in healthy control subjects, the exercise-induced mPpa-Q slope was modestly higher (1.6 ± 0.7 mm Hg/L/min, P = .03 vs dobutamine). In patients with PAH, lower functional class status was associated with lower dobutamine-induced mPpa-Q slopes (P = .014), but not with resting total pulmonary vascular resistance.

CONCLUSIONS

Noninvasive assessment of mPpa-Q relationships is feasible with dobutamine stress. DSE may potentially be a useful noninvasive technique for stress testing of the pulmonary vasculature.

Section snippets

Subjects

A total of 60 subjects participated in the study. Dobutamine stress echocardiography (DSE) was performed in healthy control subjects (n = 22) and patients with PAH (n = 16). An additional group of healthy control subjects (age- and sex-matched to the healthy control subjects who underwent DSE) who had undergone exercise echocardiography (n = 22) were used as a comparison group to understand any differences in the mPpa-Q relationships during exercise vs dobutamine stress in the normal pulmonary

Results

Baseline characteristics of the study groups are presented in Table 1. Two healthy control subjects and one patient with PAH who had undergone dobutamine stress were excluded from final analysis due to insufficient quality of echocardiographic measurements. The overall success rate for DSE was 93%.

The diagnosis of patients with PAH included idiopathic PAH (n = 6), connective tissue-associated PAH (n = 9), and portopulmonary hypertension (n = 1). Patients with PAH encompassed a range of disease

Discussion

Our study demonstrates that it is feasible to derive meaningful mPpa-Q relationships using dobutamine stress to augment Q to assess the functional state of the pulmonary circulation. Subjects with PAH revealed markedly elevated mPpa-Q slopes compared with healthy control subjects under dobutamine stress. In addition, poor functional class status in patients with PAH was associated with higher dobutamine-induced mPpa-Q slopes. The novel application of DSE for the pulmonary circulation is a

Conclusions

By using dobutamine stress to augment pulmonary flow, multipoint mPpa-Q plots can be generated to noninvasively assess the functional status of the pulmonary circulation. This is potentially more practical than exercise stress echocardiography, and dobutamine stress reveals substantial differences between healthy subjects and those with PAH. Further validation studies are required to determine the potential utility of measuring mPpa-Q response during dobutamine stress for early diagnosis,

Acknowledgments

Author contributions: E. M. T. L. served as principal author, had access to all of the data in the study, and takes responsibility for the integrity of the study data. E. M. T. L., L. R. S., T. J. C., R. N., and D. S. C. contributed to study concept and design; E. M. T. L., R. R. V., P. C., P. A., and M. D. contributed to data collection and analysis; R. N. and D. S. C. contributed to manuscript preparation; E. M. T. L. contributed to the drafting of the manuscript; R. R. V., P. C., L. R. S.,

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    FUNDING/SUPPORT: This study was supported by the National Health and Medical Research Council (NHMRC) of Australia Project [Grant 1022141 to Dr Celermajer and Dr Corte] and a NHMRC and Heart Foundation Postgraduate Scholarship to Dr Lau [No. 633136].

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.

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