In this study, a total of 188 patients, including 136 males (72.3%) and 52 females (27.7%) with acute Stanford-A AD were enrolled. The male to female ratio of total patients was 2.61:1, with an age range of 29-78 years and an average age of 59 years. There were 18 Stanford-A AD patients with HPS (case group), 13 males and 5 females. The male to female ratio of those patients was 2.6:1. The youngest was 34 years old, and the oldest was 74 years old. The average age was 60.0 years. In the control group, members were matched with 2:1 for each HPS in case group (age ≤ 5 year and the same gender). A total of 36 Stanford-A AD patients without HPS were included in the control group (26 males and 10 females, aged 29-78 years). The average age was 60.0 years old. There was no significant difference between the two groups (p>0.05). The detailed information of patients was listed in Table 1 and Table 2. Moreover, we have compared the clinical information between control group and case group. In case group, there are 16 patients with hypertension (88.9%), 3 patients with diabetes (16.7%), 5 patients with chronic cardiovascular and cerebrovascular diseases (27.8%), 2 patients with chronic lung disease (11.1%), 4 patients with moderate/severe of renal damage (22.2%), 3 patients with connective tissue disease (16.7%), 4 patients with peripheral vascular disease (22.2%), 2 patients with mild liver damage (11.1%), and one patient with tumor (5.6 %). Meanwhile, in control group, there are 34 patients with hypertension (94.4%), 7 patients with diabetes (19.4%), 12 patients with chronic cardiovascular and cerebrovascular diseases (33.3%), 4 patients with chronic lung disease (11.1%), 7 patients with severe renal damage (19.4%), 4 patients with connective tissue disease (11.1%), 7 patients with peripheral vascular disease (19.4%), 3 patients with mild liver damage (8.3%), and one patient with tumor history (2.8%). There are no significant differences of hypertension, diabetes, chronic cardiovascular and cerebrovascular diseases, chronic lung disease, moderate/severe renal damage, connective tissue disease, peripheral vascular disease, mild liver damage, and tumor history between case group and control group (p>0.05). The detailed information has been presented in Table 3. In addition, we have further compared the Charlson comorbidity index (CCI) between two groups (Table 4). The results suggested that significant differences could be detected in both groups. In case group, the median CCI was 2, the 25th percentile was 1; the 75th percentile was 3. Meanwhile, in control group, he median CCI was 1, the 25th percentile was 1; the 75th percentile was 1.5 (Table 4). There were statistical differences between the two groups in CCI index rank sum test and CCI score distribution chi-square test (P<0.05).
In this study, we have further compared the clinical symptoms, clinical signs, and MDCT features between two groups. In clinical symptoms study, we have compared six indexes, including chest pain, syncope, sudden breathing difficulty, hemoptysis or blood stasis, cough, and shortness of breath. There are no significant differences could be harvested (P>0.05) (Table 5). In clinical signs study, we have studied tachycardia, blood pressure drop, myocardial infarction or ischemia, renal failure, and abnormal liver function. The results indicated that no differences of these six indexes could be detected between two groups (P>0.05) (Table 6). In addition, we have studied the MDCT features between two groups (Table 7). The results revealed that no differences could be harvested in maximum diameter of ascending aorta (mm), aortic dissection range, pleural effusion/blood, and pericardial effusion/blood. However, patients number related with branches of the brachiocephalus and ventral branch in case group was significant higher than that in control group (P<0.001). This result indicated that main branch of aorta was an important indicator for HPS patients in case group.
Univariate conditional logistic regression analysis
In this study, HPS was used as the dependent variable Y. Meanwhile, all other factors were used as the independent variable X. We performed the univariate conditional logistic regression analysis. The results suggested that no relationships could be retrieved between age, gender, hypertension and HPS (P>0.05). However, CCI value in case group was lower than that in control group (P=0.077). In addition, we had also calculate the relationship between other MDCT features and HPS. The results suggested that close relationships could only be detected between branches of the brachiocephalus and HPS (Table 8). The results mentioned above revealed that branches of the brachiocephalus and CCI value were two risk factors for HPS patients (P<0.1).
Multivariate conditional logistic regression analysis of HPS
Based on the results of one-factor conditional logistic regression analysis, two variables with p<0.1 (CCI, branches of the brachiocephalus) were selected for multivariate logistic regression analysis. In order to avoid the false negative variables in multivariate analysis, P < 0.1 is considered to be related to HPS in one-factor conditional logistic regression analysis. Enter method was used in Multi-factor analysis. HPS was considerate as the dependent variable with a value of 1. Meanwhile, no HPS as the dependent variable assigned a value of 0. Multi-factor conditional logistic regression analysis was carried out with 1:2 match ratio (case group: control group) at the test level of ɑ=0.05. Multivariate logistic regression analysis of variable names and assignment instructions were listed in Table S3. The results suggested that branches of the brachiocephalus is an independent risk factor for HPS (OR=7.02, 95%CI=1.28-38.62, p=0.025) (Table 9).