Conference: 2010 International PHA Conference and Scientific Sessions
Release Date: 06.24.2010
Presentation Type: Abstracts
Humbarger O, Zeiger T, Heckman M, Burger C.
Mayo Clinic, Florida, Jacksonville, FL, USA
BACKGROUND: Nitric Oxide (NO), a vasodilator, is known to play a role in the pathophysiology of pulmonary arterial hypertension (PAH). Levels of fractional concentration of exhaled NO (FeNO) have been shown in preliminary studies to correlate with disease activity. We hypothesized that FeNO levels would correlate with the type and severity of PH.
METHODS: We analyzed the age, gender, type and severity of PH, WHO functional class and diagnostic group, and clinical status and treatment for 55 consecutive patients seen in the PH Clinic at Mayo Clinic Florida who had been tested for exhaled NO levels. Values were compared to 32 healthy, non-asthmatic volunteers. The data was examined using a Wilcoxon rank sum test (binary category variables), a Kruskal-Wallis rank sum test (nominal categorical variables), or Kendall’s correlation tau (numerical variables or ordered categorical variables). P-values ≤ 0.05 were statistically significant.
RESULTS: The control patients were younger (45 vs 67 years) and did not have PH. As seen in Figure 1, there is no evidence of a difference in exhaled NO levels between PH patients and controls (Median: 21 ppb vs 21 ppb, P=0.64). Similarly, in PH patients, exhaled NO was not noticeably affected by WHO class (P=0.77) or diagnostic group (P=0.37), BNP (P=0.31), six minute walk distance (P=0.77), SPAP (P=0.29), or MPAP (P=0.31).
CONCLUSIONS: There was no difference in exhaled NO levels in PH patients compared to controls. Due to the relatively small sample size, there is low power to detect associations with exhaled NO. Larger studies are needed to exclude potentially meaningful differences.
Figure 1: Exhaled nitric oxide in PH patients and volunteers. The sample median for each group is shown with a solid horizontal line.