Abstract 1370: Use of the Exercise Echocardiogram in the Diagnosis of Pulmonary Hypertension in Systemic Sclerosis
Authors:
V. K. Shanmugam, T. Kuru, R. Morrissey, V. D. Steen
Background
This study examines the utility of the exercise echocardiogram (EE) for the diagnosis of pulmonary arterial hypertension (PAH) in patients with scleroderma.
Methods
This study examined 66 subjects “at risk” for PAH. This group included patients who had unexplained dyspnea, an FVC/DLCO ratio >1.6, or a resting echo with RVSP >35 and <50. All subjects underwent an EE which included a resting echo and exercise on the Bruce protocol to 85% of maximum heart rate and repeat RVSP within one minute of completion. An EE was considered positive if the RVSP increased by 20 mmHg above resting values. Those patients with an abnormal EE were offered right heart catheterization with exercise. Patients were diagnosed as having PAH if the resting mPAP was >25 or mPAP of >30 with exercise with a normal wedge pressure.
Results
Twenty nine subjects had an abnormal EE. 25 of these patients had a RHC and 20 had evidence of PAH (8 at rest and 12 with exercise-induced PAH). An abnormal EE correlated with a decrease in DCLO and an increase in FVC/DLCO ratio. The FVC was no different between those with and without an abnormal EE, suggesting no significant confounding effect of pulmonary fibrosis. Interestingly, resting RVSP by echo did not correlate with positive EE. Of the five subjects with negative RHC, 3 had catheter evidence of diastolic dysfunction that was not noted on echocardiogram and 2 had completely normal RHC although that had suboptimal exercise. Of the 37 subjects with a negative EE, 3 patients had RHC due to high clinical suspicion of PAH. Two had normal RHC (both had isolated reduction in DLCO) and one had exercise-induced PAH (EE showed RVSP of 48 at rest increasing to 60 with exercise).
Editorial Comment
This is an interesting study examining the possible utility of EE in the diagnostic algorithm of PAH in scleroderma patients. This study examined a group of patients with high risk of having PAH, so this study is not generalizable to the overall group of scleroderma patients. This study found that these patients frequently have an abnormal EE and those patients frequently have an abnormal RHC with PAH. There were very few subjects with a negative EE that underwent catheterization, making sensitivity and specificity impossible to calculate. One could argue to cath all the subjects in this high risk group as 1/3 of the patients with a negative EE also had PAH. This study also highlights the frequency of exercise-induced PAH by RHC. This data argues that exercise should be included as a standard protocol for RHC in subjects with scleroderma. This study did not give any data on the functional status of these patients (WHO classification). It would be interesting to see this data. Presumably these would be patients detected at a lower WHO class.
