Outcomes Of Endovascular Aortic Aneurysm Repair Research Articles

Endoleak Detection after Endovascular Aortic Aneurysm Repair Using Ultrasound Based on Nanoscale Bubble Contrast Agents and Their Effects on Vascular Smooth Muscle Cell Proliferation and Migration

Abdominal aortic aneurysm (AAA) is the most common vascular disease that causes disability and death. Its morbidity is relatively subtle, and the mortality rate is high. Clinically, endovascular aortic aneurysm repair (EVAR) has gradually become the primary treatment of AAA due to its unique advantages such as low trauma and low incidence of short-term complications. However, the outcome of EVAR is greatly compromised by the possible occurrence of endoleaks. Contrast-enhanced ultrasound (CEUS) is a promising alternative technique to detect endoleaks following EVAR due to lack of exposure to ionizing radiation. Traditional ultrasound contrast agents with an overlarge size (microscale) leading to reluctant accumulation in target organs and instability trigger the requirement of nanoscale contrast agents that enter tumor tissues through the enhanced permeability and retention effect. In this study, we used ultrasound based on nanoscale bubble contrast agents to evaluate endoleak detection after endovascular aortic aneurysm repair and analyzed the effects of nanoscale bubble contrast agents on vascular smooth muscle cell (VSMC) proliferation and migration. Among 52 AAA patients a month following EVAR, there were 16 cases of endoleaks after EVAR detected by nanobubble contrast-enhanced ultrasound, including 6 cases of type I endoleak (1 case of type Ia endoleak and 5 cases of type Ib endoleak), 7 cases of type II endoleak, and 3 cases of type III endoleak; there were 12 cases of endoleak after EVAR detected by computed tomography angiography (CTA), including 6 cases of type I endoleak (1 case of type Ia and 5 cases of type Ib), 5 cases of type II endoleak, and 1 case of type III endoleak. Six months after EVAR, 3 cases of type III endoleak were detected by both nanobubble contrast-enhanced ultrasound and CTA. Vascular smooth muscle cells (VSMCs) used for in vitro experiments were subjected to ultrasound irradiation and platelet-derived growth factor (PDGF) treatment with or without the addition of nanobubble contrast agents. After high-intensity and long-term irradiation (0.75 W/cm2 and 1 W/cm2 irradiation for 120 s and 150 s, respectively) by ultrasound with or without the addition of nanobubble contrast agents, PDGF-induced VSMC migration was inhibited ( P < 0.01 ). Low-intensity and short-term ultrasound irradiation did not differ PDGF-induced VSMC migration ( P > 0.05 ), but 0.5 W/cm2 and 90 s ultrasound irradiation could significantly inhibit PDGF-induced VSMC migration without the addition of nanobubble contrast agents ( P < 0.05 ). When VSMCs were irradiated at 1, 0.75, 0.5, and 0.35 W/cm2 for 30 s to 150 s, ultrasound irradiation with or without the addition of nanobubble contrast agents remarkably reduced PDGF-induced VSMC proliferation, as evidenced by reduced OD values ( P < 0.05 ). In conclusion, ultrasound based on nanoscale bubble contrast agents is an effective alternative detection method for the occurrence of AAA patients who are not suitable for CTA.

A Single-Institution Experience With Ruptured Aortic Aneurysms

With the continued advancement in aortic endografts and increasing surgeon experience, endovascular aortic aneurysm repair (EVAR) is now commonly used for ruptured abdominal aortic aneurysms (rAAAs). Although randomized controlled trials have shown improved short-term morbidity and mortality with EVAR compared to open repair in the elective setting, the data for rAAA remain scarce. This study reviewed the data on rAAA at our institution and compared outcomes of open repair vs EVAR. All patients admitted to the University of Iowa Hospitals and Clinics between 2008 and 2015 with rAAA were identified. Demographic and clinical characteristics of patients were described using simple summary statistics. The distance from the hospital and the patients’ mode of transportation were also included. Categoric and continuous variables were analyzed using SPSS 22 software (IBM, Armonk, NY). There were 86 patients admitted to our institution with rAAA. Four were managed by palliative care, and 82 underwent surgical repair. The average distance to the local hospital at presentation was 12.5 miles, with 62.8% transported by ground and 37.2% airlifted, with an average distance of 57.7 miles. An equal number of patients (n = 41) underwent open repair and EVAR. Open femoral access was used in 47.5% of those who underwent EVAR, and 52.5% had percutaneous access. The overall mortality rate was 9.3% at 24 hours and 27.5% at 30 days. When mortality at 30 days was evaluated, there was no statistically significant difference between mode of transportation, distance from the patient’s home to the local hospital, or open repair vs EVAR. Among EVAR patients, there was no difference in 30-day mortality between type of femoral access or type of anesthesia. The primary factors associated with increased mortality were older age and increased number of medical comorbidities. In patients with rAAA, mortality appears to be more related to their age and the number of medical comorbidities rather than to the type of repair or the proximity to the hospital at the time of rupture.

Factors with Impact on the Outcome after Surgical Interventions for Abdominal Aortic Aneurysms

Since its introduction, endovascular aortic aneurysm repair (EVAR) has proved as a favourable alternative to open surgery (OR) in the treatment of abdominal aortic aneurysms (AAA). Long-term outcomes of EVAR and OR are similar while complications are more likely to develop after EVAR. Risk factors for mortality and complications after AAA surgery have been identified, however, a general overview is lacking. In a systematic literature search via PubMed, we identified publications on the topic of factors influencing the postoperative outcome of AAA surgery. Patient age > 80 years was found to be a significant predictor of increased mortality, whereas the influence of aneurysm diameter on OR remains moderate, the outcome of EVAR performed in AAA > 6.5 cm is associated with higher mortality and increased complication rates. In patients with ruptured AAA the postoperative mortality is higher than in those with intact aneurysms. Preoperative haemodynamic instability has a crucial influence on patient outcome and is strongly associated with intra- and postoperative death. The prevalence of cardiovascular co-morbidity leads to increased long-term mortality. Preoperative statin medication was found to reduce short- and long-term mortality by the factor of 0.5. Patients suffering from chronic lung disease such as COPD and patients with a deficiency in renal function are more likely to experience adverse events including death. While the prevalence of cerebrovascular disease is associated with an increase in mortality by the factor of 1.5 or higher, findings on patients with diabetes mellitus are conflicting with no definite point to be made. Several factors influencing the outcome of surgery for AAA present a condition developed from factors involved in the pathogenesis of AAA. The impact of non-disease factors like patient age and aneurysm diameter can be reduced by the means of population-wide screening for AAA, and optimised treatment of disease-related risk factors can reduce mortality. Studies comparing the outcome of EVAR and OR in patients with risk factors should be performed to support decision-making about the ideal individual treatment.

Preoperative Coil Embolization to Aortic Branched Vessels for Prevention of Aneurysmal Sac Enlargement Following EVAR: Early Clinical Result

Persistent Type 2 endoleaks (PT2) after endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) are associated with increased adverse outcomes, including aneurysmal sac enlargement and rupture. The aim of this study was to report early clinical outcomes of coil embolization (CE) to aortic branched vessels prior to EVAR and assess the effectiveness of this strategy in terms of prevention of sac growth due to PT2. Between May 2007 and April 2012, EVAR was performed for 215 cases, divided into two groups (150 cases in Group A, before introduction of CE; 21 in Group B, receiving CE before EVAR). Early clinical outcomes were compared between groups. Fifty percent of cases in Group B had a marked reduction of aneurysmal sac diameter based on multi-detector row computed tomographic angiography (MDCTA) findings at the 6-month follow-up after EVAR, whereas, only 25% of cases in Group A had shrinkage of the aneurysmal sac during the same time period after EVAR. This strategy has the possibility of improving late outcomes of EVAR by reducing endoleak volumes beforehand.