Background
In clinical practice, acute aortic dissection (AAD) is a critical disease that must be urgently treated because of the associated high risk of developing life-threatening complications. Currently, the mortality of AAD ranges from 25 to 30% [
1]. Type A aortic dissection constitutes a surgical emergency, and the mortality rates increase 1–2% per hour after symptom onset without surgical intervention [
2]. For patients with type B aortic dissection, medical management is the most selected treatment, whereas surgical treatment or endovascular stenting are performed for patients with complications such as rupture, aortic expansion, and malperfusion syndrome [
3‐
5].
Patients with end-stage renal disease (ESRD) are known to have a shorter life expectancy and a higher incidence of cardiovascular events than the average population. In addition, patients with ESRD combined with AAD have high mortality rates after both open surgical and endovascular thoracic aortic interventions [
6]. However, few studies have evaluated the clinical presentation, management, and outcomes of AAD patients with ESRD in real-world clinical practice, especially in China. Thus, the purpose of this study was to explore the differences in clinical features, management, and in-hospital outcomes of AAD patients with and without a history of ESRD. Furthermore, we sought to determine patient characteristics associated with an increased risk of in-hospital mortality in a cohort with ESRD.
Methods
Study population and data explanation
Data on patients who were admitted to hospitals with a diagnosis of AAD between 1 May 2011–30 November 2018 were obtained from the clinical research database of the First Affiliated Hospital of Gannan Medical University, Jiangxi Provincial People’s Hospital Affiliated to Nanchang University and the Affiliated Ganzhou Hospital of Nanchang University. The identification of patients hospitalized for aortic dissection was first based on the International Classification of Diseases (ICD)-10 diagnosis code I71.0. We excluded patients who were not admitted for emergency treatment. In addition, patients with chronic dissection or dissections at unspecified sites were also excluded. Baseline characteristics, clinical presentation, treatment modality, in-hospital mortality, length of hospitalization, and some specific blood biochemical indexes were analyzed. Finally, patients with AAD were categorized into 2 groups: those with and those without a history of ESRD. In this study, only patients with normal renal function (no history of CKD) or early (stage 1 or 2) CKD) were included in the group without ESRD. According to 2012 KDIGO Clinical Practice Guideline for the Evaluation and Management of CKD, patients included in the ESRD group must have a history of chronic kidney disease for at least 3 months and meet the following two criteria: the presence of estimated GFR < 15 mL/min/1.73m2 and the need for renal replacement therapy (RRT: dialysis and/or transplant). Intermediate (stages 3a to 4) CKD represents different pathophysiological processes of CKD compared with early CKD or ESRD. Thus patients with intermediate (stages 3a to 4) CKD were not included in this study. GFR was estimated by the CKD-EPI formula.
Statistical analyses
Statistical analysis was conducted using IBM SPSS Version 18.0 (SPSS Science, Chicago, IL, USA). Data are expressed as the means ± standard deviations (SDs) for continuous variables and were analyzed by Student’s t-test or the Mann–Whitney U test, while categorical variables are presented as n (%) and analyzed using the chi-square test or Fisher’s exact test. A two-sided p-value < 0.05 was considered statistically significant. Multiple logistic regression analysis was used to define the independent predictors associated with in-hospital mortality in AAD patients.
Discussion
From this study, we found that AAD patients with ESRD represent a unique population with important differences in their clinical manifestation, laboratory findings, and management. The three leading causes of ESRD were chronic glomerulonephritis, hypertension, and diabetes in this study.
For patients with ESRD, there are significant gender differences in the morbidity of AAD, with male patients having a higher incidence of AAD than female patients [
7]. Our study demonstrated a similar finding for patients with ESRD. Hypertension and especially uncontrolled hypertension are the dominant risk factors for AAD [
2]. In this study, more than 80 % of the patients had hypertension. Patients with ESRD have a higher prevalence of hypertension than those without ESRD. In addition, the ESRD group had a higher proportion of patients with systolic blood pressure over 180 mmHg on admission, which might be related to overactivation of the renin-angiotensin system and water-sodium retention in these patients [
8]. Chest or back pain, which is the most common initial symptom of AAD, usually begins suddenly and is worst at the start [
1]. However, our data indicated that patients with ESRD are less likely to present with abrupt onset chest or back pain. This is presumably a result of denervation of the cardiac sympathetic nervous system due to the significant comorbid conditions. Physicians should be aware of the atypical presentation of acute aortic tears in this cohort. Moreover, smokers and alcoholic individuals were significantly less common among the patients with ESRD in this study, which might be the result of aggressive self-control and follow-up.
Previous studies have demonstrated that inflammation plays an important role in AAD [
9]. Platelet count was identified as an independent predictor of in-hospital mortality in a recent study [
10]. Our data indicated that patients with ESRD have lower leucocyte and platelet counts than patients without ESRD on admission. However, leucocyte and platelet counts were not found to be independent predictors of in-hospital mortality by multivariate analysis.
For acute type A aortic dissection, urgent surgical repair is recommended to reduce the risk of life-threatening complications such as rupture, cardiac tamponade, severe aortic insufficiency, or stroke [
11]. Indications for surgical intervention for patients with type B aortic dissection included rupture, aortic expansion, visceral malperfusion, and intractable pain [
12]. In general, initial medical management has been the consensus for the treatment of acute type B aortic dissection unless associated with life-threatening complications. The optimal treatment of acute type B aortic dissection remains controversial [
13,
14]. Our data indicated that patients with ESRD are less likely to be treated surgically and are more often managed by conservative medical strategies. Several potential explanations may be responsible for this less aggressive approach. On the one hand, type B aortic dissection was significantly more common among patients with ESRD in this study. On the other hand, patients with ESRD are known to have a shorter life expectancy than the average population and more comorbid conditions, thus leading to the refusal of surgery by the patient and/or family.
In general, AAD patients with ESRD have higher postprocedural morbidity and mortality rates compared with those without ESRD [
15]. However, there was no significant difference between patients with and without ESRD for overall in-hospital mortality, regardless of which therapeutic modality was chosen. The underlying causes might be correlated with the higher proportion of type B aortic dissection in patients with ESRD, which offset the higher postprocedural mortality rate caused by ESRD.
Conclusions
This study highlights differences in the clinical characteristics, management, and outcomes of AAD patients with ESRD. These patients usually have atypical symptoms and more comorbid conditions and are managed more conservatively. However, these patients have no in-hospital survival disadvantage over those without ESRD. Further studies are needed to better understand and optimize care for patients with ESRD presenting with AAD.
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