Right atrial volume measured by cardiac magnetic resonance correlates with NT-ProBNP and invasive right atrial pressure in pulmonary hypertension, with and without systemic sclerosis
Journal of Cardiovascular Magnetic Resonance volume 18, Article number: P300 (2016)
Right atrial (RA) pressure (RAP) and NT-ProBNP-levels are important prognostic factors in pulmonary hypertension (PH). The aim of this study was to investigate if RA volume (RAV), emptying fraction and emptying volume measured with cardiac magnetic resonance (CMR) can be used to predict RAP, and to investigate if these measures are related to NT-ProBNP levels. Furthermore, we aimed to determine if RAV in systemic sclerosis patients with precapillary PH (PHSSc) differs from PH patients without systemic sclerosis (PHnonSSc).
We included 27 patients with PH (54 ± 19 years, 18 women). PH was defined as mPAP ≥25 mmHg and PCWP ≤15 mmHg at normal or reduced cardiac output. 11 patients with and 16 patients without Systemic Sclerosis and 35 healthy controls (age 31 ± 9 years, 16 women) underwent cine CMR to quantify end-systolic maximum (RAVmax) and end-diastolic minimum (RAVmin) right atrial volume indexed to body surface area. Invasive pressures were measured with right heart catheterization and plasma NT-ProBNP level from venous blood samples.
In all PH patients (PHSSc and PHnonSSc) mRAP was 7 ± 6 mmHg, sPAP 73 ± 23 mmHg, mPAP 46 ± 16 mmHg and PCWP 8 ± 4 mmHg. The correlation coefficient (r) between mRAP and RAVmin was 0.46 (p=0.015) and between mRAP and RAVmax 0.43 (p=0.024). Mean NT-ProBNP was 1894 ± 2381 ng/L. In the PH patients, mRAP correlated with NT-ProBNP (r = 0.5, p = 0.019). There was a strong correlation between NT-ProBNP and RAVmin (r = 0.7, p = 0.0003) and RAVmax (r = 0.67, p = 0.0006).
RAVmin in patients with PHnonSSc (97 ± 35 ml/m2) was higher as compared to PHSSc (54 ± 23 ml/m2, p < 0.05) and healthy controls (57 ± 12 ml/m2, p < 0.05), but did not differ between patients with PHSSc and healthy controls (NS). There was also a significant difference in RAVmax between the patients with PHnonSSc (69 ± 32 ml/m2) and PHSSc (32 ± 19 ml/m2, p < 0.05) as well as healthy controls (24 ± 8 ml/m2, p < 0.05), yet no difference between PHSSc and healthy controls (NS). RA emptying fraction differed between the PHnonSSc patients and the healthy controls (31 ± 12% vs. 54 ± 15%, p < 0.05), but neither between PHSSc patients (43 ± 18%) and healthy controls nor PH patients (ns). There was no significant difference in RA emptying volume between the groups PHnonSSc (29 ± 13 ml/m2), PHSSc (21 ± 11 ml/m2) and the healthy controls (31 ± 10 ml/m2).
This study shows that non-invasive measures of right atrial volumes by cardiac magnetic resonance correlates with NT-ProBNP and invasive right atrial pressure in patients with precapillary PH. Furthermore, RAVmin and RAVmax were increased in PHnonSSc compared to PHSSc. Future studies are needed to investigate the clinical advantages of these complementary measures in the diagnostics of pulmonary hypertension.
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Gyllenhammar, T., Steding-Ehrenborg, K., Carlsson, M. et al. Right atrial volume measured by cardiac magnetic resonance correlates with NT-ProBNP and invasive right atrial pressure in pulmonary hypertension, with and without systemic sclerosis. J Cardiovasc Magn Reson 18 (Suppl 1), P300 (2016). https://doi.org/10.1186/1532-429X-18-S1-P300