Anemic Hypoxia Is Associated With Pulmonary Arterial Hypertension In Patients With Systemic Lupus Erythematosus

Ki-Jo Kim¹, In-Woon Baek², Chong-Hyeun Yoon³, Jin-Jung Choi⁴, Wan-Uk Kim² and Chul-Soo Cho⁵, ¹Internal Medicine, St. Vincent’s Hospital, The Catholic University of Korea, Suwon, South Korea, ²Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, South Korea, ³Internal Medicine, Uijeongbu St. Mary's Hospital, The Catholic University of Korea, Uijeongbu, South Korea, ⁴Internal Medicine, CHA University Hospital, Seongnam, South Korea, ⁵Internal Medicine, Yeouido St. Mary's Hospital, The Catholic University of Korea, Seoul, South Korea

Meeting: ACR/ARHP Annual Meeting 2013

Keywords: Anemia, interleukins (IL), pulmonary complications and systemic lupus erythematosus (SLE)

Session Information

Title: Systemic Lupus Erythematosus - Clinical Aspects I - Renal, Malignancy, Cardiovascular Disease

Session Type: Abstract Submissions (ACR)

Background/Purpose: Pulmonary arterial hypertension (PAH) is a serious and often fatal complication of systemic lupus erythematosus (SLE), but its pathogenesis is still unclear. Hypoxia-induced pulmonary vascular remodelling has been suggested to be a crucial mechanism for PAH. We investigated the association between anemic hypoxia and PAH in patients with SLE.

Methods: A post hoc analysis was performed of the prospective cross-sectional study to determine the PAH in 116 patients with SLE. PAH was defined as resting pulmonary artery systolic pressure (PASP) ≥ 40 mmHg by echocardiography. Duration of anemia was calculated as cumulative months of anemia (defined by hemoglobin [Hb]<10 g/dL) during the preceding years. Oxygen delivery (DO₂) was estimated by the product of cardiac output (CO) and arterial oxygen content (CO x %Saturation x 1.39 x Hb). Serum IL-6 level and plasma N terminal-pro B-type natriuretic peptide (NT-proBNP) were also quantified.

Results: Among 116 SLE patients, PAH was detected in 11 patients (9.5%). The range of PAH was 40.4-90 mmHg. Twenty-one patients (18.1%) showed PASP of 30-40 mmHg. Compared to patients without PAH, patients with PAH had lower Hb levels (9.8±0.5 versus 11.9±0.2 g/dL, P=0.001), but longer duration of anemia during the preceding 1, 2, and 3 years, respectively (all P<0.05). Importantly, DO₂ value of patients with PAH were significantly lower than those of patients without PAH (7.9±0.8 versus 10.0±0.2 ml/min/kg, P=0.006). Moreover, DO₂ value inversely correlated with PASP and serum NT-proBNP levels (γ=-0.241, P=0.013 and γ=-0.292, P=0.001, respectively). In multivariate regression analysis, duration of anemia was independently associated with the presence of PAH in SLE patients (P=0.006). When patients were divided into three groups according to tertiles of Hb well as PASP, serum IL-6 significantly increased across the tertiles of PASP (P for trend=0.038), but decreased across the tertiles of Hb (P for trend=0.001).

Conclusion: Our study suggests that prolonged exposure to anemic hypoxia, which is associated with increased serum IL-6, might be a component of pathogenesis of PAH in SLE patients.

Disclosure:

K. J. Kim,
None;

I. W. Baek,
None;

C. H. Yoon,
None;

J. J. Choi,
None;

W. U. Kim,
None;

C. S. Cho,
None.

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