Outcomes of endovascular repair of infrarenal penetrating aortic ulcers
Insights from the abdominal aortic aneurysm registry of the German Institute for Vascular Research
Abstract
Summary:Background: To report technical success as well as perioperative outcomes of patients who underwent endovascular aortic repair (EVAR) of penetrating abdominal aortic ulcers ≤35 mm in diameter (PAU). Patients and methods: The abdominal aortic aneurysm (AAA) quality registry of the German institute for vascular research (DIGG) was used to identify patients with standard EVAR for infrarenal PAU ≤35 mm between 1/1/2019 and 12/31/2021. Infectious, traumatic, inflammatory PAUs, PAUs associated with connective tissue disease, PAUs following aortic dissection as well as true aneurysms were excluded. Demographics, cardiovascular comorbidity, technical success as well as perioperative morbidity and mortality were determined. Results: Amongst 11 537 patients who underwent EVAR during the study period, 405 with PAU ≤35 mm were eligible from 95 participating hospitals across Germany (22% women, 20.5% octogenarians). The median aortic diameter was 30 mm (Interquartile range 27–33). Cardiovascular comorbidities were frequent with coronary artery disease (34.8%), chronic heart failure (30.9%), history of myocardial infarction (19.8%), hypertension (76.8%), diabetes (21.7%), smoking (20.8%), history of stroke (9.4%), symptomatic lower extremity peripheral arterial disease (20%), chronic kidney disease (10.4%) and chronic obstructive pulmonary disease (9.6%). Most patients were asymptomatic (89.9%). Among the symptomatic patients, 13 presented with distal embolization (3.2%) and 3 with contained ruptures (0.7%). Technical success of endovascular repair was 98.3%. Both, percutaneous (37.1%) or femoral cut-down access approaches (58.5%) were registered. Endoleaks of any type were present with type 1 (0.5%), type 2 (6.4%) and type 3 (0.3%) endoleaks. Overall mortality was 0.5%. Perioperative complications occurred in 12 patients (3.0%). Conclusions: According to this registry data, endovascular repair of PAU is technically feasible with acceptable perioperative outcomes, but further studies investigating mid- and long-term data are needed before invasive treatment of PAU disease in an elderly and comorbid patient population should be recommended.
Introduction
Penetrating aortic ulcer (PAU) is defined as an ulceration that penetrates the internal elastic lamina and allows hematoma formation within the media of the aortic wall [1]. With wide-spread use of computed tomography angiography asymptomatic PAU has become a relevant incidental finding from opportunistic screening. The European Society for Vascular Surgery (ESVS) 2019 Guidelines on the Management of Abdominal Aorto-iliac Artery Aneurysms recommended serial imaging in uncomplicated cases and invasive repair in patients with complicated PAU. Factors which usually indicate complicated lesions comprise extra-aortic hematoma, embolization symptoms, recurrent pain, a PAU that initially measures >20 mm in width or >10 mm in depth or progression of total aortic diameter [2]. However, the decision to repair asymptomatic patients may be challenging. A recently published study by DeCarlo et al. examining small PAUs with a mean aortic diameter of 31.4 mm (95% confidence interval, CI, 30.1–32.7) concluded that asymptomatic PAU was associated with a benign natural course with a cumulative incidence of PAU-related complications of 6.5% at 10 years after diagnosis [3]. This raises the question of outcomes of endovascular repair in these patients to facilitate risk assessment. Evidence on both, technical and clinical outcomes of endovascular treatment of patients with abdominal PAU remains limited to small retrospective observational series with mainly short-term follow-up [4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20].
This study aimed to determine perioperative outcomes of patients who underwent endovascular repair of small PAU (≤35 mm). We used German-wide data of the abdominal aortic aneurysm (AAA) quality assurance registry of the German Institute for Vascular Research (DIGG).
Patients and methods
The AAA quality assurance registry of the German Institute for Vascular Research (DIGG) consecutively collects data from more than 120 centers (2022) and was used for this study. All patients who underwent endovascular or open repair for AAA, PAU and abdominal aortic dissection are eligible for the registry. Data is manually entered into a web-based case-report-form. Participation is voluntary for all centers.
In this registry-based retrospective observational study, all patients treated with endovascular aortic repair (EVAR) for infrarenal PAU with a maximum diameter ≤35 mm between 1/1/2019 and 12/31/2021 were included. Infectious, traumatic, inflammatory PAUs, PAUs associated with connective tissue disease and PAUs secondary to aortic dissection as well as true aneurysms were excluded. Patients with juxtarenal, pararenal or suprarenal PAUs as well as patients who underwent fenestrated, branched or chimney EVAR were also excluded.
Abdominal PAU is defined as a focal, localized outpouching of contrast material in the presence of atherosclerosis with a variable extent of intramural hematoma [4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20].
Ethical approval was provided by the Institutional Review Board of the University Hospital Heidelberg (S-806/2020). The study was conducted according to STROBE guidelines [21].
Outcomes
Baseline demographics, cardiovascular comorbidity, maximum aortic diameter (in mm, outer-to-outer diameter), basic procedural data with technical success, and perioperative clinical outcomes are reported. Technical success was defined as successful delivery and deployment of the device without unintentional coverage of renal or internal iliac arteries and without type 1 or type 3 endoleak at completion [22].
Statistical analysis
Results are presented descriptively with median and interquartile range (IQR) as well as mean and standard deviation (SD). Proportions were reported with %. Missing data was handled by case wise exclusion. Statistical analysis was performed using the statistic software R [23].
Results
Patient population
Between 1/1/2019 and 12/31/2021, 405 patients (3.5%) treated at 95 participating hospitals (median 4.3 patients per hospital) fulfilled the inclusion criteria. Patient population is displayed in Figure 1.
Comorbidity and cardiovascular risk factors
Eighty-nine (22.0%) patients were female. Eighty-three (20.5%) patients were ≥ 80 years of age. The median maximum aortic diameter was 30 mm (IQR: 27–33, mean: 29.2, SD: 5.3), minimum: 10, maximum: 35). Median Body-Mass-Index was 25.6 (IQR 23.4–28.7, mean: 26.2, SD: 4.3).
A total of 141 patients (34.8%) had coronary artery disease. 125 (30.9%) had chronic heart failure. Three hundred and eleven (76.8%) had hypertension, 88 (21.7%) had diabetes, 82 (20.2%) were smokers and 80 (19.8%) patients had a history of myocardial infarction. Thirty-eight (9.4%) patients had a history of stroke and 81 (20.0%) patients had a history of symptomatic lower extremity peripheral arterial disease. Chronic kidney disease was present in 42 (10.4%) patients with 7 (1.7%) patients having an estimated glomerular filtration rate <30 ml/min/1.73 m2. Thirty-nine (9.6%) patients had chronic obstructive pulmonary disease.
A total of 269 (66.4%) patients were classified as having severe systemic disease (American Society for Anesthesiology, ASA class 3) and 19 (4.7%) had a constant threat to life (ASA class 4). Comorbidities are presented in Tables I and II.
Clinical presentation
Most patients (364, 89.9%) were treated for asymptomatic PAU. The remaining 41 (11.1%) patients were treated for symptomatic PAU. Of these, the symptoms comprised distal embolization in 13 (3.2%) cases as well as 3 (0.7%) contained ruptures. The remaining 25 patients’ symptoms were neither embolization nor rupture, but not specified in detail.
Baseline demographics andcomorbidities, are summarized in Tables I and II.
Technical success, endoleaks, postoperative hospital length of stay
One hundred and forty-nine (36.4%) patients were treated via a bilateral percutaneous and 253 (58.5%) via a bilateral cut-down vascular access or unilateral cut-down and contralateral percutaneous access (4.5%). Forty-five (11.1%) patients required either femoral reconstruction or iliac angioplasty with or without stent implantation. Endoleaks of any type were present with type 1 (0.6%), type 2 (6.5%) and type 3 (0.2%) endoleaks. The status with regards to unintentional coverage of renal and/or internal iliac arteries was reported for only 361 patients. Among these, there were two (0.5%) unintentional stentgraft-associated renal artery occlusions. Additionally, there was one (0.2%) open surgical conversion, resulting in a technical success rate according to the above-mentioned definition of 355/361 (98.3%). Postoperative complications occurred in 12 (3.0%) patients. The median postoperative length of hospital stay was 5 days (IQR: 4–6) and 14 (3.5%) patients required treatment on the intensive care unit (ICU) >1 day. Seven (1.7%) patients required blood transfusion. Two patients (0.5%) with an asymptomatic PAU died during the hospital stay. The detailed sequelae that led to death could not be extracted. Procedural details, endoleaks, and complications are presented in Tables III and IV.
Discussion
The present study determined acceptable perioperative morbidity and mortality of endovascular repair of small PAU over a 3-year period from a German-wide national quality improvement registry. Evidence on the management of patients with abdominal PAU is limited to case series and small observational studies with generally short periods of follow-up [4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 24]. Data on the natural history of this entity in the abdominal aorta is also limited, thereby hampering decision making in clinical practice. A recent single-center study has demonstrated a rather benign natural history in 97 patients with small abdominal PAUs with a mean diameter of 31.4 mm and a low PAU-related complication rate at 10 years after diagnosis [3].
In the present registry cohort, only 10% of patients were symptomatic and only 3 (0.7%) patients presented with contained ruptures at the time of treatment, which is lower than in previous studies reporting 25–100% for symptoms and 0–32% for ruptures [4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19].
This might indicate a more liberal indication to repair in the German healthcare system for small PAU over the study period when compared to previous studies and is in line with the suggestion of a rather benign natural history of small PAU disease [3]. When compared to true abdominal aortic aneurysm disease undergoing repair (AAA), the previously published data from the German institute for vascular research from 2019 reported a proportion of 9.7% ruptured AAA compared to a rupture rate of 0.7% for small PAU in the present study [25].
High technical success rates with endovascular repair for abdominal PAU have been continuously reported in the literature [4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 24]. Accordingly, the rates of type 1 and 3 endoleaks were low, as was the incidence of type 2 endoleak which is indicative of the focal nature of abdominal PAU disease with involvement of potentially less infrarenal aortic branches when compared to abdominal aortic aneurysm disease.
While in most patients endovascular repair was technically successful, as expected, the minimally invasive treatment of PAU was still associated with considerable mortality and morbidity. Interestingly, about two thirds of patients were treated via a femoral cut-down access which is associated with prolonged hospitalization. Additionally, about 10% of patients required adjunctive procedures such as femoral artery reconstruction or iliac angioplasty with or without stent implantation, which demonstrates the atherosclerotic burden of these patients. Overall, morbidity and mortality were within an acceptable range for endovascular repair and similar like in previous reports [4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]. However, all potential technical and clinical complications must be weighed in against the risk that is associated with the natural history of the disease [3]. Furthermore, data on mid- and long-term outcomes with the potential of late complications such as limb occlusion are lacking. Considering the benign natural history of small abdominal PAUs and the comorbidity of the cohort in this study as well as the unknown overall long-term prognosis of these elderly patients, invasive treatment early after diagnosis should not be recommended. Instead, until further evidence is available, imaging surveillance 3 months after initial diagnosis and reevaluation of repair appears to be a reasonable management strategy as was previously suggested [3]. Additionally, further observational studies with long-term follow-up are required to gain an understanding of the natural course of this pathology and to enable more accurate assessment of its associated risks.
Limitations
There are several limitations of the present study that need to be considered. First, this is a retrospective analysis of registry data which naturally limits data quality, also due to missing data. While data of 95 participating hospitals could be included, the degree of detail is limited. Important data like aortic morphology especially width and depth of the PAU, devices used, including configuration, as well as more detailed data on comorbidity, clinical presentation, and complications are lacking. Furthermore, there were no unified definitions used for comorbidities. Eight (2.0%) patients were reported to have a maximum aortic diameter <15 mm. This might be erroneous data or patients that were treated for penetrating ulcer of the common iliac artery. It illustrates one of the major limitations of the study, that there was no original imaging available for review. This can also be an indicator for the application of different diagnostic criteria applied by the different vascular surgeons involved in the treatment of PAU patients which could have introduced bias and implicates a need for a unified and precise nomenclature and core-laboratory assessment of PAU studies. Second, it needs to be acknowledged that not all patients treated during that period have been entered into the registry, which results in the potential of selection bias. The detailed rationale for repair in the participating hospitals remains unknown after all. Therefore, results might not be generalizable. Furthermore, there was no data on follow up as well as no sufficient data on reinterventions available for analysis. Moreover, this study only included standard EVAR. More recently, balloon-expandable stent grafts have been used in infrarenal PAU disease with promising initial results. The optimal endovascular management strategy has yet to be determined.
Despite these limitations, this is to our knowledge the largest series reporting on perioperative outcomes of endovascular repair of small PAU. This study provides an estimate of the associated morbidity and mortality of endovascular repair based on nation-wide data. It was furthermore shown that despite its rarity asymptomatic PAU disease is of relevance for clinical practice and requires further research with mid-term and long-term follow-up data to allow more definite clinical practice guidelines.
Conclusions
Based on this registry data, endovascular repair was associated with high technical success and acceptable perioperative morbidity and mortality in patients with small PAU. However, a higher level of evidence, a better understanding of the natural history of abdominal PAU disease and associated rupture risks are needed before invasive treatment in asymptomatic patients should be recommended.
We thank all participating centers of the AAA quality assurance registry.
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