OBJECTIVES: Complement activation as evidenced by C4d deposition indicates immunological tissue reactivity. We sought to study the vascular reactivity of the aortic wall by characterizing C4d deposits. DESIGN: Aortic wall histology and immunohistochemistry for C4d, leukocytes, T- and B-lymphocytes, plasma cells, macrophages, endothelial cells, smooth muscle cells, cell proliferation, elastase, and Van-Gieson-staining were performed to 91 consecutive patients that underwent surgery for ascending aorta, and the samples were grouped according to presence of C4d deposits. RESULTS: Fifty-three out of 91 patients had C4d deposits mainly within the adventitia (C4d +), whereas 38 patients lacked C4d deposits (C4d-) including decreased staining of intra-aortic vessels (p < 0.005). Intimal thickness and cellularity, together with inflammation consisting of plasma cells were increased in C4d- as compared with C4d + (p < 0.05). Receiver operating characteristic curve (ROC) analysis showed that C4d was associated with stabile nondissecting ascending aorta (AUC 0.792; SE 0.053; p = 0.000; 95% CI 0.688-0.895), but not with presence of aortitis per se (AUC 0.523; SE 0.069; p = 0.752; 95 % CI 0.388-0.658). CONCLUSIONS: Lack of C4d may indicate active remodeling of the aortic wall leading to aortic dissection (AD). Immunologic complement factors may be amenable to diagnosis of instability after aortic surgery.
OBJECTIVES: Complement activation as evidenced by C4d deposition indicates immunological tissue reactivity. We sought to study the vascular reactivity of the aortic wall by characterizing C4d deposits. DESIGN: Aortic wall histology and immunohistochemistry for C4d, leukocytes, T- and B-lymphocytes, plasma cells, macrophages, endothelial cells, smooth muscle cells, cell proliferation, elastase, and Van-Gieson-staining were performed to 91 consecutive patients that underwent surgery for ascending aorta, and the samples were grouped according to presence of C4d deposits. RESULTS: Fifty-three out of 91 patients had C4d deposits mainly within the adventitia (C4d +), whereas 38 patients lacked C4d deposits (C4d-) including decreased staining of intra-aortic vessels (p < 0.005). Intimal thickness and cellularity, together with inflammation consisting of plasma cells were increased in C4d- as compared with C4d + (p < 0.05). Receiver operating characteristic curve (ROC) analysis showed that C4d was associated with stabile nondissecting ascending aorta (AUC 0.792; SE 0.053; p = 0.000; 95% CI 0.688-0.895), but not with presence of aortitis per se (AUC 0.523; SE 0.069; p = 0.752; 95 % CI 0.388-0.658). CONCLUSIONS: Lack of C4d may indicate active remodeling of the aortic wall leading to aortic dissection (AD). Immunologic complement factors may be amenable to diagnosis of instability after aortic surgery.