Is the Size of an Abdominal Aortic Aneurysm Associated with Coagulopathy?

Abdominal aortic aneurysm (AAA) volume and intraluminal thrombi were analyzed with respect to the number and function of platelets, blood cells, and coagulation factors. A group of 43 patients who underwent repair of an AAA were enrolled in this study. The maximum diameter and volume of the AAA, and the volume of intraluminal thrombi and lumen were measured by computed tomography with planimetry. The platelet count and platelet function, prothrombin time, activated partial thromboplastin time, fibrinogen, plasminogen, antithrombin 3, fibrin degradation products (FDP), D-dimer, and blood cell counts were measured. Spontaneous platelet aggregation and the FDP, and D-dimer levels were elevated; all other factors remained within the normal range. Intraluminal thrombus volume was strongly correlated with the volume and diameter of the AAA. However, no correlation was observed between the size of the AAA and coagulating factors, including the number and aggregation value of platelets. AAAs are frequently associated with a coagulating disorder. However, its size and thrombus volume are not correlated with coagulation changes. Although an intraluminal thrornbus increases along with fee enlargement of the AAA, the clinical manifestation of bleeding is rarely associated with an AAA. Therefore coagulopathy in patients with an AAA is not fully explained by its morphology.     

Are Periods of Low Atmospheric Pressure Associated with an Increased Risk of Abdominal Aortic Aneurysm Rupture?

INTRODUCTION

Seasonal variation in rates of abdominal aortic aneurysm (AAA) rupture has previously been described. However, only two studies, to date, have suggested that periods of low atmospheric pressure may account for this observation and both returned apparently contradictory findings. The objective of this study was to demonstrate whether periods of low atmospheric pressure are indeed associated with an increased likelihood of AAA rupture presentation.

PATIENTS AND METHODS

A total of 182 cases of ruptured AAA were identified retrospectively from two centres over a 6-year period from January 2000 to December 2005. Local meteorological data for the corresponding period was obtained from the UK Meteorological Office which was recorded daily at a local weather station. Statistical analysis using Student''s t-test, ANOVA (Kruskal–Wallis), linear regression and multiple logistic regression was conducted to identify significant relationships from the data.

RESULTS

Days of rupture presentation were associated with a significantly lower daily mean atmospheric pressure when compared with days when no rupture occurred (P = 0.025). Multiple logistic regression demonstrated a significant association between low daily atmospheric pressure and rupture incidence (P = 0.033) which appeared to be independent of temperature. A significant seasonal trough in atmospheric pressure was observed in October and November (Kruskal–Wallis, P < 0.001); however, there was no corresponding autumnal peak in rupture incidence (P = 0.232).

CONCLUSIONS

The findings of this study appear to confirm the assertion that low atmospheric pressure is associated with an increased risk of AAA rupture on a day-to-day basis; however, no evidence was identified to support a change in policy regarding prioritising elective surgery based on seasonal risk.     

Are we Ignoring the Importance of Ankle Pressures in Patients with Abdominal Aortic Aneurysm?

BACKGROUND AND PURPOSE: the ankle/brachial pressure index (ABPI) has been shown to be a reliable marker of cardiovascular risk in population studies. We investigated whether the ABPI was a useful prognostic index for patients with abdominal aortic aneurysm. METHODS: patients entered into the U.K. Small Aneurysm Trial and Study had their ABPI measured in both legs at baseline (mean ABPI reported) and were followed up until 30 June 1998, with information about cause of death being obtained from the Office of National Statistics. This study focussed on cardiovascular and all-cause mortality. RESULTS: a total of 1827 men and 478 women, mean age 69 years, median aneurysm diameter 4.4 cm, were followed up for a median of 5.7 years. A total of 829 deaths were reported (rate 8.1 per 100 person-years), 546 (66%) from cardiovascular causes. The all-cause mortality risk increased as the ABPI decreased, hazard ratio 1.25 per 0.2 unit decrease in ABPI (95% CI 1.17 to 1.34, p<0.001). For patients in the lowest tertile group (ABPI <0.87) there were 11.6 deaths per 100 person-years. This increased risk persisted after adjustment for age, sex, evidence of ischaemia on resting ECG and initial aneurysm diameter, adjusted hazard ratio 1.17 per 0.2 unit decrease in ABPI (95% CI 1.07 to 1.28, p<0.001). CONCLUSION: the ankle/brachial pressure index is an important prognostic indicator for patients with abdominal aortic aneurysm. Patients with an ABPI below 0.87 (limit of lowest tertile) have the highest mortality risk and best clinical practice demands that attention is focussed on active treatment to minimise their cardiovascular risk factors.     

What Determines and Are the Consequences of Surveillance Intensity after Endovascular Abdominal Aortic Aneurysm Repair?

Follow-up examinations are advised 1, 3, 6, 12, 18, and 24 months and yearly thereafter by the European Collaborating Group on Stent-Graft Techniques for Abdominal Aortic Aneurysm Repair (EUROSTAR). The aim of this study was to evaluate the determinants and consequences of surveillance completeness. Patients who underwent endovascular abdominal aortic aneurysm repair between October 1996 and August 2004 and enrolled in the EUROSTAR registry were analyzed. Two groups were compared: patients who attended all scheduled visits (group A) and those who came infrequently (group B). Odds ratios and hazard rates (HRs) with 95% confidence intervals (CIs) were determined to detect which patient characteristics and complications were associated with follow-up intensity. Of the 4,433 patients, 1,538 (35%) attended all scheduled visits until the end of follow-up (group A). Analysis of patient characteristics demonstrated that intensive visitors were more often smokers, hyperlipemic, and considered unfit for open surgery or general anesthesia. Complications during follow-up, including endoleaks (24% vs. 20%), kinking (3.5% vs. 2.5%), and migration (4.9% vs. 3.5%), appeared significantly more frequently in group A. Despite intensive follow-up of this category, still a greater proportion died (12% vs. 9%, adjusted HR = 1.5, 95% CI 1.2-1.8). After 84 months of follow-up, the cumulative survival rates in groups A and B were 71% and 74%, respectively (p < 0.0001). It seems that follow-up intensity was based on baseline patient characteristics. High-risk patients had, despite more intensive surveillance, still more complications after adjustment for patient, morphological, and center-specific characteristics. Further assessment is indicated to evaluate the effectiveness of different frequencies of surveillance visits.     

What Are the Longterm Results of Conventional Open Surgical Repair of Abdominal Aortic Aneurysms ?

Purpose : To determine the longterm results of conventional open surgical repair of abdominal aortic aneurysms (AAAs) and the prevalence of late arterial abnormalities.

Methods : CT scan follow-up was obtained between 8 and 9 years after elective AAA repair on a cohort of patients enrolled in the Canadian Aneurysm Study, a registry that originally consisted of 680 patients. A request for CT follow- up was sent to the responsible surgeon in 1994 when 251 patients were alive and available. Ninety-four of the 251 patients agreed to undergo an abdominal and thoracic CT scan, and each scan was interpreted independently by two vascular radiologists.

Results : The aorta was analysed in five defined segments, and an aneurysm was defined as > 50% enlargement from the expected normal value as defined in the Reporting Standards for Aneurysms. Using this strict definition, 64.9% of patients had an aneurysm, but the abnormality was considered a possible indication for surgical repair in 13.8%. Of the 39 patients who had an initial repair with a tube graft, 12 (30.8%) were found to have an iliac aneurysm and 6 (15.4%) were considered to be of possible surgical significance. The median graft size at the time of operation was 18 mm, which increased to a median size of 22 mm at follow-up. Fluid or thrombus around the graft was observed in 28%, and bowel was intimately associated with the graft in 7%.

Conclusions : The longterm results of conventional open surgical repair is durable. CT scan follow-up between 8 and 9 years postoperatively often demonstrates aortic and iliac abnormalities, but the majority are not clinically significant. On the basis of these findings, a routine CT scan of the abdomen and chest is recommended after 5 years. This study provides a population based study for comparison with the longterm results of endovascular repair.     

Is the Incidence of Abdominal Aortic Aneurysm Declining in the 21st Century? Mortality and Hospital Admissions for England & Wales and Scotland

BackgroundBetween 1951 and 1995 there was a steady increase in age-standardised deaths from all aortic aneurysms in men, from 2 to 56 per 100,000 population in England &; Wales, supporting an increase in incidence. More recently, evidence from Sweden and elsewhere suggests that now the incidence of abdominal aortic aneurysm (AAA) may be declining.MethodsNational statistics for hospital admissions and deaths from AAA, after population age-standardisation, were used to investigate current trends in England &; Wales and Scotland.ResultsBetween 1997 and 2009 there has been a reduction in age-adjusted mortality from AAA from 40.4 to 25.7 per 100,000 population for England &; Wales and from 30.1 to 20.8 per 100,000 population in Scotland. The decrease in mortality was more marked for men than women. Mortality decreased more than 2-fold in those <75 years versus 25% only in those >75 years. During this same time period the elective hospital admissions for AAA repair have only increased in the population >75 years.ConclusionsThese data suggest that the age at which clinically-relevant aneurysms present has increased by 5–10 years and that incidence of clinically-relevant AAA in men in England &; Wales and Scotland is declining rapidly. The reasons for this are unclear.     

Increased Incidence of Renal Cysts in Patients with Abdominal Aortic Aneurysms: A Common Pathogenesis?

We have empirically observed that patients with abdominal aortic aneurysms (AAAs) seem to have an increased incidence of renal cysts on computed tomography (CT). In order to evaluate this possible association, a retrospective cohort study was conducted comparing the incidence of renal cysts on CT scan in 100 patients with AAA to 100 patients without AAA (matched by age and gender). Univariate analysis and multiple logistic regression were performed to evaluate the association of AAAs and other risk factors with the presence of renal cysts. Of patients with AAAs, 54% had renal cysts compared to only 30% in the control group (p = 0.0006, relative risk = 2.73). The AAA group had a higher incidence of chronic obstructive pulmonary disease (COPD, 14% vs. 1%), hypertension (76.6% vs. 46.5%), coronary artery disease (38.3% vs. 12%), and hypercholesterolemia (41.5% vs. 9.1%) compared to the non-AAA group. There was a significant linear correlation between renal cysts and COPD (p = 0.011), the presence of AAA (p = 0.0005), and age (p = 0.019), whereas hypercholesterolemia (p = 0.059) and diabetes (p = 0.063) approached significance. On multivariate analysis, there were three independent predictors of renal cysts: COPD (p = 0.051), age (p = 0.01), and AAA (p = 0.028). In conclusion, there is a significantly higher incidence of renal cysts in patients with AAA compared to patients without AAA. To our knowledge, this association has not previously been reported. Future studies are needed to determine whether this correlation is the result of a commonality in the pathogenesis of AAA and renal cysts.     

Endovascular Thoracic Aortic Repair and Previous or Concomitant Abdominal Aortic Repair: Is the Increased Risk of Spinal Cord Ischemia Real?

Spinal cord ischemia after endovascular thoracic aortic repair remains a significant risk. Previous or concomitant abdominal aortic repair may increase this risk. This investigation reviews the occurrence of spinal cord ischemia after endovascular repair of the descending thoracic aorta in patients with previous or concomitant abdominal aortic repair. Over an 8-year period, 125 patients underwent endovascular exclusion of the thoracic aorta at the Mount Sinai Medical Center. Twenty-eight of these patients had previous or concomitant abdominal aortic repair. The 27 patients who underwent staged repairs all had cerebrospinal fluid (CSF) drainage during and following repair. This population was analyzed for the complication of spinal cord ischemia and factors related to its occurrence. Mean follow-up was 19.3 months (range 1-61). Spinal cord ischemia developed in four of the 28 patients (14.3%) who underwent endovascular thoracic aortic repair with previous or concomitant abdominal aortic repair, while one of 97 patients (1.0%) developed ischemia among the remaining thoracic endograft population. One patient with concomitant abdominal aortic repair developed cord ischemia that manifested 12 hr following the procedure. The remaining three patients with previous abdominal aortic repair developed more delayed-onset paralysis ranging from the third postoperative day to 7 weeks following repair. Irreversible cord ischemia occurred in three patients, with full recovery in one patient. Major complications from CSF drainage occurred in one patient (3.7%). Spinal cord ischemia occurred at a markedly higher rate in patients with previous or concomitant abdominal aortic repair. This risk continued beyond the immediate postoperative period. The benefit of perioperative and salvage CSF drainage remains to be determined.     

Progression of Abdominal Aortic Aneurysm After Endovascular Stent-Grafting in a Patient with Behçet's disease: Report of a Case

A 53-year-old man with Behçet's disease was admitted to our hospital for investigation of back and lower abdominal pain. Computed tomography (CT) showed a projecting saccular aneurysm below the right renal artery. We placed a stent-graft just below the right renal artery, successfully excluding the abdominal aortic aneurysm (AAA). His C-reactive protein level and white blood cell count remained elevated after stent-grafting. About 5 months later, he was readmitted with recurrent back and lower abdominal pain and CT showed progression of the AAA. Thus, we performed straight grafting using a woven Dacron graft just below the right renal artery. The patient had an uneventful postoperative course. We discuss the controversial issue of treating AAA in patients with Behçet's disease, focusing on the indications and timing of surgery.     

Endovascular Repair of Inflammatory Abdominal Aortic Aneurysms: A Valuable Alternative?—Case Report and Review of Literature

While endovascular repair (ER) has become a routine procedure in the treatment of arteriosclerotic abdominal aortic aneurysms with a suitable configuration, only rare reports of interventional treatment of inflammatory aortic abdominal aneurysms (IAAA) exist. We present a case study of a male patient with IAAA, who presented with inflammatory thickening involving the entire circumference of the aortic vessel wall. The MRI performed 8 months after successful ER demonstrated complete regression of vessel wall induration. A patient with the appropriate anatomical configuration of IAAA should benefit from the lower morbidity and mortality of endovascular aneurysm repair (EVAR). In our view, EVAR is preferable to open surgical repair in the specific situation of IAAA.