Predictors of Abdominal Aortic Aneurysm (AAA) Growth and AAA Rupture Risk Besides AAA Size: Fact or Fiction?

Abstract

Flondell-Sité et al in this issue of Angiology report that besides abdominal aortic aneurysm (AAA) diameter (P ¼ .0019), endothelin-1 (ET-1) levels (P ¼ .0230) were significant predictors of AAA growth in 178 patients with AAA followed conservatively (mean: 2.9 + 1.6 years).1 In univariate analysis, ET-1 levels also predicted death or need for AAA surgery.1 These results suggest an alternative/additional predictor of AAA growth and rupture risk besides AAA diameter.Currently, the main criterion for AAA repair is an AAA diameter 5.5 cm.2 The 5.5-cm diameter threshold is the size when the AAA rupture rate balances the mortality rates of elective AAA repair (3%).2 However, some AAAs rupture when they are smaller and many are discovered after they have exceeded this critical diameter but have not ruptured.3 It therefore seems that size alone is not sufficient to assess AAA rupture risk. The discovery of alternative predictors of AAA growth and rupture risk holds implications for a more appropriate (earlier/later) surgical management of AAAs.This Editorial discusses potential predictors of AAA growth and rupture risk besides AAA diameter and ET-1. i) 18F-fluorodeoxyglucose (FDG) uptakeMetabolic processes, such as chronic inflammation and proteolysis, play a pivotal role in AAA formation and rupture. [4][5][6] Increased 18F-FDG metabolism measured by positron emission tomography (PET) computed tomography (CT) scans have been described in aortic infection, arteritis, inflammation, as well as symptomatic AAAs. 7,8 A recent study demonstrated increased aortic 18F-FDG metabolism in patients with asymptomatic AAAs compared with healthy controls (mean maximum standard uptake values [SUV max ], 3.5 + 0.6 vs 3.0 + 0.5, respectively; P < .05). Furthermore, patients with symptomatic AAAs had significantly higher focal 18F-FDG metabolism compared with individuals with asymptomatic AAAs (mean SUV max , 7.5 + 0.3 vs 3.5 + 0.6, respectively; P < .05). These findings lead the authors to conclude that ''18F-FDG PET CT imaging might be a new approach to identify AAAs at risk before acute aneurysm onset. '' 9 Although promising, these preliminary results need to be validated in appropriately designed trials. i) Pulse-wave velocity (PWV)Our group recently investigated the prognostic value of the carotid-femoral aortic PWV (a marker of arterial stiffness and cardiovascular risk and a possible predictor of AAA rupture risk)10-12 before and after elective open AAA repair. 13 Patients (n ¼ 24) scheduled for an open AAA repair underwent 2 carotid-femoral aortic PWV measurements; 1 preoperatively and another 6 months later. A polytetrafluoroethylene aortobifurcated graft (aortobi-iliac or aortobi-femoral) was introduced in all patients. Mean aortic PWV increased from 7.84 + 1.85 preoperatively to 10.08 + 1.57 m/s 6 months postoperatively (P < .0001). However, the preprocedural PWV measurement did not correlate with AAA diameter (Spearman rank correlation coefficient r ¼ .12; P ¼ .594). 13In normal aortas, the propagation of the pulse wave i...

Application of hyperbaric oxygen therapy in diabetic foot ulcers: A meta‐analysis

“…6 In recent years, some adjunctive treatments such as hyperbaric oxygen have been shown to not only improve the healing rate of diabetic foot wounds, but also reduce amputation rates. 7 Hyperbaric oxygen therapy (HBOT) involves breathing pure oxygen in a hyperbaric chamber at more than one atmosphere of pressure, which passively raises oxygen tension in arteries and tissues. 8 It has been found that hyperbaric oxygen improves vascular blood flow in the lower limbs of patients, promotes local blood and oxygen supply, improves neuropathy in the tissues surrounding the diabetic foot, enhances tissue metabolism, reduces inflammatory exudation and reduces or eliminates oedema, thus accelerating ulcer healing.…”

“…Over the years, diabetic foot treatments have included the administration of improved microcirculation, proper control of blood glucose levels, regular local debridement and dressing changes, anti‐infection, nerve nutrition and amputation 6 . In recent years, some adjunctive treatments such as hyperbaric oxygen have been shown to not only improve the healing rate of diabetic foot wounds, but also reduce amputation rates 7 . Hyperbaric oxygen therapy (HBOT) involves breathing pure oxygen in a hyperbaric chamber at more than one atmosphere of pressure, which passively raises oxygen tension in arteries and tissues 8 .…”

Expanding Current EVAR Indications to Include Small Abdominal Aortic Aneurysms: A Glimpse of the Future

“…This Editorial discusses AAA geometrical parameters and peak wall stress as the potential predictors of AAA growth and rupture risk. 9 Identifying the Problem Abdominal aortic aneurysm is largely a disease of elderly men, being 2 to 6 times more common in males than in females. 10 It appears in men around the age of 50 and reaches a peak incidence near the age of 80, whereas in women the onset of the disease is more delayed, following a steady increase thereafter.…”

18F-Fluorodeoxyglucose Uptake in Abdominal Aortic Aneurysms: A Useful Biomarker of AAA Rupture Risk

“…Increased 18F-FDG uptake in AAAs is associated with inflammation, aortic wall instability, and rupture risk [ 6 ]. Therefore, 18F-FDG uptake might be a new technique to study AAA disease in vivo and may improve prediction of AAA rupture risk [ 6 , 7 ]. The prognostic value of 18F-FDG uptake was verified by a study reporting increased focal uptake of 18F-FDG in patients with large, rapidly expanding, or symptomatic AAAs that are prone to rupture [ 8 ].…”