Page 104 - Assessing right ventricular function and the pulmonary circulation in pulmonary hypertension Onno Anthonius Spruijt

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Figure 4: Treatment response in oxygenation and 6MWD. 6MWD = 6 minute walking distance; SaO2 rest = arterial oxygen saturation in rest; SaO2 rest-ex = change in arterial oxygen saturation during exercise. * = p<0.05. Data is presented as mean ± SEM.
Survival analyses
LVEDVI and LVESVI proved to be confounders to the survival analysis. LVEDVI and age-corrected survival was worse for patients with a DLCO<43% (figure 5A). These survival differences between DLCO<43% and DLCO 43-62% and DLCO>62% were also present in the selected cohort with a CMRI available at follow-up (figure 5B). No difference in survival was seen between patients with and without a CMRI at follow-up in the DLCO<43% group (figure 5C).
Discussion
In the present study we evaluated the effects of pulmonary hypertension specific vasodilatory therapy in IPAH patients with a severely reduced DLCO. It is known that IPAH patients with a low DLCO have a worse survival compared to IPAH patients with a preserved DLCO [6]. In addition, it has been shown that IPAH patients with a low DLCO have more coronary artery disease, a higher tobacco exposure, a higher body mass index, are older, have worse pulmonary function tests and show more mild abnormalities on HRCTs compared to IPAH patients with a preserved DLCO [5]. Although it seems that the IPAH patients with a low DLCO share some risk factors with group 2 and group 3 PH, normal PAWP pressures, spirometry and HRCT excluded left heart conditions and lung disease as a cause of PH. In addition, HRCTs of the IPAH patients with a low DLCO showed no signs of PVOD [14,15]. The question rises whether the low DLCO group has a different pulmonary vasculopathy compared to IPAH patients with a preserved DLCO [7,8]. The answer to this question remains elusive and requires further investigation. As a first step, we analyzed the treatment response in this patient cohort.