Conference: 2008 International PHA Conference and Scientific Sessions
Release Date: 06.20.2008
Presentation Type: Abstracts
Georgetown University, Washington, DC, USA
BACKGROUND: Pulmonary arterial hypertension (PAH) is now the most common cause of scleroderma (SSc) related deaths. We have recently shown that SSc patients whose estimated RVSP increased by >20mmg on exercise (+EE) had a high likelihood of having either PAH on right heart catheterization (CATH) (Chest, 2008). This study looks at EE in patients with different SSc autoantibodies.
METHODS: EEs using a standard Bruce protocol were performed on SSc patients with some increased risk for PAH. Patients with a +EE then underwent an exercise CATH. Patients with an anti-centromere (ACA), anti-topoisomerase (Scl-70) or a nucleolar pattern (NUC) were compared. A FVC%/DLCO% ratio (RATIO) > 1.6 was abnormal.
RESULTS: There were 50 patients in this study, 22 ACA, 13 Scl-70, and 25 NUC patients.
|FVC%/DLCO% (ratio)||100/66 (1.6)||64*/51 (1.4)||86/59 (1.5)|
|Resting PASP (mmHg)||33.2||35||34.6|
|Mean increase (mmHg)||17.1||14.4*||18.8|
|Left atrial diameter (cm)||3.25||3.28||3.58*|
More patients with an abnormal RATIO had a +EE, 67% vs 28% (p<0.003), but a + EE did not correlate with the resting RVSP. In the 10 ACA patients with a +EE, 2 (on CATH) had resting PAH, 6 had exercise induced PAH with a normal mean PAP at rest and a mean PAP > 30 mmHg at exercise and 1 (age 77) had diastolic dysfunction (DD) with a normal resting wedge which increased to 25 with exercise. Of the 4 Scl -70 patients with a +EE, all had resting hypoxemia, severe fibrosis, 3 had an abnormal RATIO, 3 had mild resting PAH on CATH (mean PAP 28mmHg) and 1 had DD (prior renal crisis). The NUC patients were different. Many had fibrosis but no hypoxia. The mean LA diameter was significantly greater than other groups, More than half (13) had a +EE, and more than half of those (7) did not have an abnormal RATIO. On CATH, 2 had resting PAH, 3 had exercise PAH and 8 had DD. Six with DD had an increased wedge only on exercise. The DD patients had a mean age of 52 years and 1 had prior renal crisis. Their mean LA diameter was 3.7cm.
CONCLUSIONS: Positive EE may be seen in SSc patients at increased risk for PAH. Auto- antibodies are strongly associated with the type PAH seen in these patients. ACA patients consistently have a typical vasculopathy type of PAH. Scl-70 patients less commonly have a +EE and their PAH is milder and hypoxic driven. The NUC patients have more false positive EEs because of a high frequency of DD. These patients did not have obvious DD on EE although the LA diameter was statistically greater. Importantly, in most patients the increased wedge only occurred with exercise. These findings suggest that patients with a +EE even with a ‘normal’ resting RVSP may have exercise induced PAH. An exercise CATH may be necessary to rule out DD in some SSc patients.