Stress echocardiography in the evaluation of exercise physiology in patients with severe arterial pulmonary hypertension. New methodology

Abstract

Introduction: Doppler echocardiography is usually performed when assessing a patient with severe pulmonary hypertension (PHT), since it enables accurate determination of the severity of the hypertension through evaluation of several morphologic and hemodynamic variables. Echocardiograms are usually performed in left lateral decubitus (LLD). However, symptoms often arise only in a standing position and particularly during exercise.

Objective: To evaluate a group of patients with severe PHT using Doppler echocardiography during treadmill exercise testing.

Methods: We studied 8 patients (group A), mean age 43.88 +/- 14 years, 7 women; three had idiopathic pulmonary hypertension, 2 pulmonary thromboembolic disease, 2 Eisenmenger syndrome, and one pulmonary hypertension associated with celiac disease. We also studied an 8-patient control group (group B) with similar demographic characteristics, who had tricuspid regurgitation but no known cardiac disease, including pulmonary hypertension (excluded by echocardiogram). In addition to the ergometric variables of stress test duration using the modified Bruce protocol, resting heart rate, peak heart rate (PHR), resting systolic blood pressure (RSBP) and peak systolic blood pressure (PSBP), we evaluated the following echocardiographic variables: pressure gradient between right ventricle and right atrium (RV/RAg) and systolic volume (SV) in left lateral decubitus, in a standing position (SP) and at peak workload (PW). Stress testing was stopped in cases of fatigue and/or dyspnea.

Results: In group A, the RV/RAg in LLD was 100 +/- 20 mmHg, 98 +/- 20 mmHg in SP (p = NS) and 129 +/- 27 mmHg at PW (p = 0.003 vs. SP). In group B, the RV/RAg in LLD was 19.8 +/- 3.5 mmHg, 14.6 +/- 2.1 mmHg in SP (p = 0.0005) and 29.5 +/- 3.3 mmHg at PW (p < 0.0001 vs. SP). In group A, SV was 38 +/- 11 ml in LLD, 35 +/- 10 ml in SP and 32 +/- 9 ml at PW (p = NS); in group B, it was 63 +/- 5 ml in LLD, 55 +/- 5 ml in SP and 64 +/- 7 ml at PW (p < 0.0001). PHR was 114 +/- 10 bpm in group A and 145 +/- 8 (p < 0.0001) in group B. RSBP was 113 +/- 13 mmHg and PSBP 112 +/- 21 mmHg (p = NS) in group A, and 116 +/- 18 mmHg and 161 +/- 25 mmHg respectively (p < 0.0001) in group B. In four patients from group A, symptomatic falls in systolic blood pressure and SV occurred at PW. During a mean follow-up of 27 months (between 6 and 44 months), two of these four patients died and one is awaiting lung transplantation.

Conclusions: 1. RV/RAg did not diminish in the standing position and rose significantly with orthostatic isotonic exercise during exercise testing in patients with severe PHT, with pulmonary artery systolic pressure reaching suprasystemic values. 2. Systolic volume and systolic blood pressure did not rise during exercise in patients with severe PHT, and patients with a decrease in systolic volume had worse clinical evolution. 3. Patients with severe PHT appeared to have chronotropic incompetence during exercise compared to the control group.