PURPOSE: Right heart catheterization (RHC) with vasoreactivity testing using short acting agents is performed toidentify vasodilator responsive Pulmonary artery hypertension (PAH) cases that may benefit fromlong term calcium channel blocker therapy. Conflicting evidence exists regarding the value of apositive pulmonary vasodilator test to predict better survival. This study is the first of its kind tocompare the prognostic predictors among PAH patients who do not respond to vasodilator challengeduring RHC.
METHODS: A clinic based retrospective study design with PAH patients was employed. A total of 43 PAH caseswho did not respond to vasodilator challenge with nitrous oxide (NO) were included in the study.Previously described prognostic predictors such as the 6 minute walking distance(6MWD),biochemical markers and various hemodynamic parameters were assessed in the studypopulation.
RESULTS: The study population comprised predominantly of females (79%) and African Americans (42%) , witha mean age of 60.41 years. A Pearson's correlation coefficient for pre and post vasodilatation meanpulmonary artery pressure mPAP was significant (r=0.810, p<0.001).The study subjects were furtherstratified into 3 groups on the basis of drop in mPAP after NO challenge: Group 1 with decrement of5-9mm of Hg in mPAP,Group 2 with decrement of 0-4 mm of Hg in mPAP and Group 3 withdecrement of 10 mm or more drop in mPAP (but unable to reach absolute value of 40 mm of Hg). Aseries of non parametric test (data was non normally distributed) were computed and significantdifferences were found between the 3 groups respectively based on 6MWD (m) (281.7±28.8vs225.5±20.9 vs 207.3±9.8, p<0.04) ,NYHA class(2.4±0.2 vs 2.8±0.9 vs 3.0±.0,p<.001) and Rightatrial pressure(mm) (8.4±2.4 vs12.6±1.1 vs 9.0±1.0 ,p<.02 ).
CONCLUSION: PAH cases with higher magnitude of change in pulmonary artery pressure among non responders tovasodilator challenge have better prognostic predictors.
CLINICAL IMPLICATIONS: This study evokes the need for additional research with PAH cases to evaluate the predictors fordegree of responsiveness to vasodilator challenge.
DISCLOSURE: Amit Chopra, No Financial Disclosure Information; No Product/Research Disclosure Information