PURPOSE: Pulmonary arterial hypertension (PAH) is associated with increased mortality in patients with systemic sclerosis (SSc) and has worse outcomes compared to other types of PAH. Decreased heart rate recovery (HRR) after exercise is associated with an all cause-increased mortality in pulmonary and non-pulmonary diseases. We evaluated whether decreased HRR correlates with prognostic markers and presence of interstitial lung disease (ILD) in patients with SSc-related PAH (SSc-PAH).
METHODS: Heart rate at 1-minute post 6MWT is collected as a variable as per the modified protocol of our PFT lab. Demographic, clinical, hemodynamic, PFT and 6MWT variables were collected in patients who had SSc-PAH and had a 6MWT from August 2009 to March 2010. HRR1 was defined as the difference in the heart rate at the end of 6MWT and at one minute after completion of the 6MWT.
RESULTS: 35 patients with SSc-PAH had 6MWT from Aug 09-March 10. None of the patients were on chronotropic medications nor had clinical/hemodynamic evidence of left heart failure. Mean age was 58.97 years, 88.5% were females, mean mPAP was 38.95 mm Hg, mean plasma BNP was 258.7 pg/ml, mean eRVSP based on echo was 64.18 mmHg,mean PCWP was10.60 mm Hg, mean 6MWD was 334.3 meters, mean HRR1 was 15.77 bpm. 77 % ( 28/35) of the patients were on PAH specific therapy. HRR1 was significantly lower in patients with WHO class III/IV symptoms, elevated BNP levels (BNP > 100 pg/ml), and moderate to severe RV dysfunction on echo. HRR1 was not significantly different between the ILD and the non ILD subgroups. HRR 1 was not significantly different in the PAH medication group vs the non medicated group.
CONCLUSION: HRR1 in patients with Ssc-PAH correlates with BNP levels but does not correlate with mPAP , mRAP, DLCO or 6MWD. Patients with WHO class3/4 symptoms, moderate-severe RV dysfunction and elevated BNP levels had significantly lower HRR1.
CLINICAL IMPLICATIONS: HRR1 after 6MWT may be useful as a surrogate marker of elevated BNP levels in SSc-PAH patients.
DISCLOSURE: Srinivas Mummadi, No Financial Disclosure Information; No Product/Research Disclosure Information