Journal List > J Rheum Dis > v.22(1) > 1064189

Lee, Yim, Park, Chung, and Lee: Correlation of Cardiothoracic Ratio and Right Ventricular Systolic Pressure in Systemic Sclerosis



This study was designed to assess sequential association between right ventricular systolic pressure and cardiothoracic (C/T) ratio of chest radiography in systemic sclerosis (SSc) patients and inferred pulmonary arterial hypertension by increased C/T ratio and right ventricular systolic pressure.


Twenty-eight consecutive patients with confirmed SSc (22 females, 6 males; mean age 51.1±2.1 years), with a mean time of 91.0±6.7 months from SSc diagnosis, were prospectively included in the study. C/T ratio was obtained by chest radiography with an interval of two years. The first C/T ratio was taken at diagnosis and second C/T ratio was taken at the time of enrollment. The enrolled subjects were agree to undergo echocardiography and measurement of brain natriuretic peptide.


In 24 SSc patients with normal right ventricular systolic pressure, 10 SSc patients had increased C/T ratio, the other four SSc patients with increased right ventricular systolic pressure by echocardiography, had increased C/T ratio all together. In four SSc patients with increased right ventricular systolic pressure, one patient had resting dyspnea, taken cardiac catheterization and confirmed as pulmonary hypertension and the other three patients had no clinical symptoms. The increased right ventricular systolic pressure is related to the increase of C/T ratio (>0.55) in chest radiography (p<0.05) and increased brain natriuretic peptide in blood (p<0.05).


The increase of C/T ratio (>0.55) in chest radiography was associated with increased right ventricular systolic pressure measured by echocardiography and inferred a role in early detection of asymptomatic pulmonary arterial hypertension in SSc patients.


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Figure 1.
The correlation of right ventricular systolic pressure and cardiothoracic ratio difference. Scatter plots of cardiothoracic ratio showed slightly positive correlations with right ventricular systolic pressure (Spearman correlation co-efficient=0.2, p-value<0.05, relative risk: 4.0 [95% confidence interval: 2.0∼7.9]).
Figure 2.
The correlation of brain natriuretic peptide and cardiothoracic ratio difference. Scatter plots of cardiothoracic ratio showed positive correlations with brain natriuretic peptide (spearman correlation coefficient=0.2, p-value<0.05, relative risk: 1.1 [95% confidence interval: 0.0∼1.3]).
Figure 3.
The correlation of right ventricular systolic pressure and brain natriuretic peptide. Scatter plots of brain natriuretic peptide showed slightly positive correlations with right ventricular systolic pressure (spearman correlation co-efficient=0.7, p-value<0.05, relative risk: 1.1 [95% confidence interval: 0.0∼1.3]).
Table 1.
Characteristics of the 28 patients enrolled in this study
  Increased right ventricular systolic pressure patients (n=4) Normal right ventricular systolic pressure patients (n=24) p-value
Female (n) 4 18 0.001
Median age (yr) 60.5 (28∼73) 51.0 (32∼68)  
Median disease duration (mo) 102.0 (12.2∼120.1) 91.0 (11.4∼119.8)  
With ILD (n) 4 9  
 UIP/NSIP 1/3 2/7  
Mean pulmonary arterial pressure (mmHg) 57.3±2.7 25.0±4.9 0.7
With anti-scl-antibody (n) 3 12 0.007
With anti-centromere-antibody (n) 1 3 0.1
Median BNP (pg/mL) 183.0 (30.0∼896.4) 52.1 (12.4∼267.1)  
Median C/T ratio (%) 0.6 (0.37∼0.59) 0.5 (0.37∼0.55)  

Values are presented as number only, median (range), or mean±standard deviation. BNP: brain natriuretic peptide, C/T ratio: cardiothoracic ratio, ILD: interstitial lung disease, NSIP: nonspecific interstitial pneumonitis, UIP: usual interstitial pneumonia.

Table 2.
Affecting factors for elevated right ventricular systolic pressure in echocardiography
Variable Univariate analysis
Multivariate analysis
Coefficient (β) 95% CI p-value Coefficient (β) 95% CI p-value
Duration −0.2 −0.3∼0.7 0.578 −0.1 −0.4∼0.2 0.778
Age 0.0 −0.1∼0.4 0.783 0.0 −0.2∼0.3 0.887
Sex 0.4 0.0∼1.1 0.598 0.1 −0.2∼0.4 0.649
Body mass index 0.2 −0.0∼0.5 0.201 0.1 −0.0∼0.3 0.157
Brain natriuretic peptide 0.1 0.0∼0.7 0.001 0.8 0.1∼1.4 0.002
Cardiothoracic ratio 0.1 −0.5∼1.0 0.003 1.0 −1.7∼1.3 0.003
Interstitial lung disease 0.0 −0.1∼0.7 0.765 0.1 −0.2∼0.5 0.565

95% CI: confidence interval to β.

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