Association between atherosclerosis and parenchymal lung involvement in systemic sclerosis

Systemic sclerosis is an autoimmune disease affecting connective tissues, (including epidermal, subepidermal, microvasculature, etc.), leading to various extent of end-organ damage. The leading cause of mortality among these patients is lung involvement. The cardiovascular events happen more frequently in patients suffering systemic scleroderma, comparing to healthy population. This study was designed to clear the correlation between development of coronary calcification (as an indicator of atherosclerosis) and lung disease in these patients.

All patients with definite diagnosis of systemic sclerosis, who referred to Shahid Modarres Hospital between March 2011and March 2014, entered to the study. Patients suffering hypertension, hyperlipidemia and who had a past or current history of smoking were excluded from the study. Atherosclerosis was determined by coronary calcium score (based on Agatston score) and the severity and extent of lung disease was assessed by wells scoring system and Warrick scoring system (based on lung CT scan without contrast). The spearman correlation analysis was done on the data by SPSS software, version 20 (IBM SPSS, Armonk, NY, USA). All the patients had informed consent and no additive charge was delivered.

The study population consisted of 25 patients with systemic sclerosis. 21 patients were female and the 4 other ones were male. The mean age was 67±4 years old. The mean Wells score in patients was 13±2.59, the mean Warrick severity score was 6.54±6.16 and the mean Warrick extent score was 14.42±14.59. No correlation was observed between presence of calcification in coronary arteries (Wells score r2=0.63  P=0.77, severity score r2=0.27, P=0.2, extent score r2=0.11, P=0.6), aorta annulus (Wells score r2=0.04, P=0.83, severity score r2=0.06, P=0.77, extent score r2=0.06,  P=0.76) and thoracic aorta (Wells score r2=0.05, P=0.83, severity score r2=0.03, P=0.9, extent score r2=0.03, P=0.9) with the severity and extent of lung involvement.

It seems that the presence of coronary atherosclerosis or calcifications in aorta annulus and thoracic aorta (assessed by Agatston calcium score) has no significant correlation with the severity and extent of lung disease (assessed by Wells and Warrick score) in patients with systemic sclerosis.