We have used exercise echocardiograms to try and detect early pulmonary vascular disease; this study was to see if information from these studies could predict disease progression.
We retrospectively reviewed the reports of 112 patients with a resting tricuspid regurgitation (TR) gradient < 35 mmHg on their initial treadmill exercise echocardiogram, and at least one follow up study. The average patient age was 53 years (range 25–81 years) with a male:female ratio of 1:6. The average number of exercise echos was 3 (range 2–11). The average time between the initial and most recent treadmill exercise echos was 35 months (range 3–101 months).
On the initial study, the 112 patients achieved an average workload of 8 METS (range 3–15 METS). At maximal exercise, the TR gradient increased by < 15mmHg in 31 patients (28%), by 16–25mmHg in 43 patients (39%), by 26–35mmHg in 30 patients (26%), and by > 35mmHg in 8 patients (7%). On the most recent follow-up studies, 25/112 (22%) patients had increased their resting TR gradient to > 35mmHg (35–45mmHg: 20 patients; 45–55mmHg: 3 patients; > 55mmHg: 2 patients). On the initial exercise echos of these 25 patients, 6 (24%) had increased their TR gradient by < 15mmHg, 11 (44%) by 16–25mmHg, 6 (24%) by 26–35mmHg, and 2 (8%) had increased their TR gradient by > 36mmHg. 8 of these 25 patients had increased their resting TR gradients by > 15mmHg. On the initial exercise echocardiograms, 4 of these patients had increased their maximal TR gradients by 15–25mmHg, 2 by 26–25mmHg and 2 by > 35mmHg.
Significant increases in TR gradient with exercise are concerning, however, the increase in TR gradient during treadmill exercise echocardiography does not distinguish those patients who will progress to have resting PH (TR > 35mmHg) from those who will not.
Analysis of parameters other than TR gradient is needed to improve the utility of exercise echocardiograms in the prediction of progression of early pulmonary vascular disease.
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