Chee V. Soong

The impact of radiation dose exposure during endovascular aneurysm repair on patient safety

OBJECTIVE Endovascular aneurysm repair (EVAR) exposes patients to radiation during the procedure and in subsequent follow-up. The study goal was to calculate the radiation dose in our unit and compare it against other published data and national guidelines. METHODS All EVAR procedures were identified from a prospectively maintained database. Radiation dose, screening time, and volume of intravenous contrast during the procedure were reviewed. Radiation exposure from subsequent computed tomography (CT) imaging was included in the overall exposure. Results are expressed as mean +/- standard deviation. RESULTS From October 1998 to October 2008, 320 elective patients underwent EVAR. Mean screening time was 29.4 +/- 23.3 minutes, and the radiation dose was 11.7 +/- 7.1 mSv. The EVAR was an emergency in 64 patients. The mean screening time was 22.9 +/- 18.2 minutes, and the radiation dose was 13.4 +/- 8.6 mSv. During the first postoperative year, follow-up CT scans exposed the patients to 24.0 mSv, with 8.0 mSv in subsequent years. Abdominal radiographs added an additional 1.8 mSv each year. CONCLUSION EVAR and the follow-up investigations involve substantial amounts of radiation, with well-recognized carcinogenic risks. Because patient safety is paramount, radiation exposure should be minimized. This may be possible by standardizing radiation exposure throughout the United Kingdom by implementing national guidelines and considering other imaging modalities for follow-up.

The effects of abdominal compartment hypertension after open and endovascular repair of a ruptured abdominal aortic aneurysm

OBJECTIVE This study assessed if emergency endovascular repair (eEVR) reduces the increase in intra-abdominal compartment pressure and host inflammatory response in patients with ruptured abdominal aortic aneurysm (AAA). METHODS Thirty patients with ruptured AAA were prospectively recruited. Patients were offered eEVR or emergency conventional open repair (eOR) depending on anatomic suitability. Intra-abdominal pressure was measured postoperatively, at 2 and 6 hours, and then daily for 5 days. Organ dysfunction was assessed preoperatively by calculating the Hardman score. Multiple organ dysfunction syndrome, systemic inflammatory response syndrome, and lung injury scores were calculated regularly postoperatively. Hematologic analyses included serum urea and electrolytes, liver function indices, and C-reactive protein. Urine was analyzed for the albumin-creatinine ratio. RESULTS Fourteen patients (12 men; mean age, 72.2 +/- 6.2 years) underwent eEVR, and 16 (14 men; mean age, 71.4 +/- 7.0 years) had eOR. Intra-abdominal pressure was significantly higher in the eOR cohort compared with the eEVR group. The eEVR patients had significantly less blood loss (P < .001) and transfused (P < .001) and total intraoperative intravenous fluid infusion (P = .001). The eOR group demonstrated a greater risk of organ dysfunction, with a higher systemic inflammatory response syndrome score at day 5 (P = .005) and higher lung injury scores at days 1 and 3 (P = .02 and P = .02) compared with eEVR. A significant correlation was observed between intra-abdominal pressure and the volume of blood lost and transfused, amount of fluid given, systemic inflammatory response syndrome score, multiple organ dysfunction score, lung injury score, and the length of stay in the intensive care unit and hospital. CONCLUSION These results suggest that eEVR of ruptured AAA is less stressful and is associated with less intra-abdominal hypertension and host inflammatory response compared with eOR.

C-reactive protein (CRP) elevation in patients with abdominal aortic aneurysm is independent of the most important CRP genetic polymorphism

OBJECTIVE C-reactive protein (CRP) is a marker of cardiovascular disease. The objective was to determine if abdominal aortic aneurysm (AAA) and CRP serum concentration and its CRP gene are associated. METHODS AND RESULTS AAA patients and AAA negative controls were recruited. CRP concentration was measured and the single nucleotide polymorphism (SNP), rs3091244, assessed. AAA cases were divided into those measuring 30-55 mm and >55 mm in diameter, to assess correlation of CRP with AAA size. A total of 248 (227 male) cases and 400 (388 male) controls were included. CRP concentration was higher in cases (385.0 microl/dL [310.4-442.8] vs 180.3 microl/dL [168.1-196.9]; P < .0001). It was higher in large aneurysms (685.7 microl/dL [511.8-1083.0] vs 291.0 microl/dL [223.6-349.6]; P < .0001), with significant correlation observed to size (r = 0.37, P < .0001). CC was the most common SNP genotype with no difference in distribution (P = .43) between cases and controls. No difference existed in CRP for each genotype in the overall cohort (P = .17), cases (P = .18) and controls (P = .19). CONCLUSION The results demonstrate that CRP production may be related to the presence of AAA, especially in advanced disease. The serum concentration of CRP does not appear to be influenced by the functional SNP of the CRP gene, which also appears to have no association with AAA formation.

Benefits of a Supervised Exercise Program After Lower Limb Bypass Surgery

This study evaluated the efficacy of an exercise program after arterial bypass surgery. Patients undergoing bypass surgery were randomized to a control group (group I), with standard preoperative and postoperative care, or the intervention group (group II) with a supervised exercise program of twice-weekly treadmill assessments from 4 to 10 weeks postoperatively. Ankle-brachial pressure indices and hemodynamic measurements were recorded before and after exercise. The mean increase of maximum walking distance was 3.8% in group I and 175.4% in group II (P = .001). There was a significant difference between group I and II in the mean ankle-brachial pressure indices increase at the second assessment (0.08 versus 0.23; P = .02). A supervised exercise program leads to better improvement after lower limb bypass surgery for ischemia, but the feasibility of a formal exercise program would be undermined by the reluctance of patients to participate, both in the short-term and long-term.

Risk factors for abdominal aortic aneurysm and the influence of social deprivation.

Introduction: the objective of this abdominal aortic aneurysm (AAA) screening study was to determine attendance and disease prevalence patterns in Northern Ireland and the role of deprivation and other risk factors. Patients and methods: patients from primary care practices from Belfast, Lisburn, and Saintfield were screened. Past medical history and deprivation details were determined. Results: 2264 men from Belfast, 1104 men in Lisburn, and 284 in Saintfield were invited to attend. Overall, 1659 (45.3%) men attended, with 40.6% from Belfast, 55.0% from Lisburn, and 45.8% from Saintfield (P < .0001). Ninety-two (5.5%) new AAAs were diagnosed, with 6.5%, 3.8%, and 6.2% in the 3 areas (P = .055). As deprivation decreased, attendance increased and prevalence decreased. Smoking, peripheral arterial disease, number of medications prescribed, and geographical origin were independent risk factors for AAAs. Conclusion: aneurysm prevalence is influenced by geographical origin and deprivation, which should, therefore, be important factors in health care planning and screening provision.

Bilateral popliteal artery occlusion in a competitive bike rider: case report and clinical review.

Since its first description in 1879, popliteal artery entrapment syndrome remains a debilitating condition, which frequently affects young active people. Increased awareness of popliteal artery entrapment syndrome combined with improvements in investigative modalities has resulted in a more frequent diagnosis of this eminently treatable condition. In this article, a rare case of bilateral popliteal artery entrapment syndrome in a physically active 33-year-old man precipitated by competitive Bicycle Moto-Cross riding is presented. A higher index of suspicion for popliteal artery entrapment syndrome is recommended as the underlying pathology in a young active person with symptoms of lower limb claudication. Popliteal artery entrapment syndrome should be investigated with thorough radiological assessment prior to any therapeutic intervention, which is often fraught with difficulty due to chronically diseased vasculature and inherent anatomical anomalies.

The Role of Smoking in Abdominal Aortic Aneurysm Development

Abdominal aortic aneurysm is common. The aim of this study was to assess the effect of smoking on prevalence and management. Patients attending the vascular unit and appropriate controls were prospectively recruited. A smoking history revealed tobacco exposure in pack years. Serum cotinine was assessed biochemically. Independent risk factors were statistically determined. In all, 202 (186 men) patients were recruited, with 202 (197 men) controls. A total of 69 patients tested positive for cotinine, whereas 39 controls were positive (P = .001). Smoking and ischemic heart disease were significant predictors for aneurysm prevalence. Cardiac disease emerged as a more important predictor than smoking in symptomatic patients. In noncardiac patients, smoking and hypercholesterolemia were significant risk factors. Smoking is a significant predictor for aneurysm development. In high-risk patients, the cardiac disease process is the most important factor, with control of this imperative. However, in noncardiac patients, smoking cessation and lipid-lowering therapy are crucial.

No Difference in Medium-Term Outcome Between Zenith and Talent Stent-Grafts in Endovascular Aneurysm Repair

Background Many devices are available for endovascular aneurysm repair (EVAR). Our aim was to analyze morphological effects of the Zenith and Talent systems. Methods Patients included underwent EVAR from June 1999 to June 2005 using a Zenith or Talent stent-graft, with computed tomography follow-up. Aortic dimensions over time and clinical outcome were analyzed. Results Twenty-nine patients with Zenith stent-grafts and 33 with Talent devices were included. Mean preoperative age was similar (75.5 ± 6.0 years vs 74.2 ± 6.7 years; P = .29). Preoperative neck length was longer in the Zenith group (29.9 ± 15.2 mm vs 25.5 ± 10.8 mm; P = .10), and stent-graft oversizing was greater in the Talent patients (20.2% ± 7.9% vs 23.0% ± 11.3%). There was proximal aortic dilatation and aneurysm sac shrinkage in each group. Complication rates were comparable, with 83% of both groups free from 10-mm migration. Conclusion Although device designs differ, there is no difference in clinical outcome between Zenith and Talent stent-grafts. Migration rates were not influenced by suprarenal fixation.

The effects of cilostazol on peripheral neuropathy in diabetic patients with peripheral arterial disease.

Background Evidence from diabetic animal models suggests that cilostazol, a cyclic AMP phosphodiesterase inhibitor used in the treatment of claudication, is efficacious in the treatment of peripheral neuropathy, although this is unproven in humans. The main aim of this study was to assess the effects of cilostazol on neuropathic symptomatology in diabetic patients with peripheral arterial disease (PAD). Methods Diabetic patients with PAD were prospectively recruited to a randomized double-blinded placebo-controlled trial. Baseline clinical data were recorded prior to trial commencement following medical optimization. Neurological assessment included the Toronto Clinical Neuropathy Scoring system (TCNS) and vibration perception thresholds (VPT) with a neurothesiometer at baseline, 6 weeks, and 24 weeks. Results Twenty-six patients were recruited from December 2004 to January 2006, which included 20 males. Baseline patient allocation to treatment arms was matched for age, sex, and medical comorbidities. There was no significant difference in neurological assessment between the treatment groups using the TCNS and VPT at 6 and 24 weeks. Conclusions Despite extensive animal-based evidence that cilostazol attenuates neuropathic symptomatology, our results do not support this effect in human diabetic PAD patients.

Common polymorphisms of Fibulin-5 and the risk of abdominal aortic aneurysm development

Fibulin-5 is a crucial protein in the connective tissue structure of the aortic wall. The purpose of this study was to determine if genetic variation within the Fibulin-5 gene was associated with abdominal aortic aneurysms (AAA). AAA patients, with disease-free controls, were recruited and a past medical history questionnaire completed. Three single nucleotide polymorphisms (SNPs) in the FBLN5 gene (rs2498834, rs2430366 and rs2254320) were genotyped. The two cohorts were compared and haplotype analysis performed. A total of 230 AAA cases and 278 controls were successfully genotyped. The mean age was 71.9 years (± 6.8). No difference between cases and controls was found in the distribution of alleles of FBLN5 SNPs rs2498834 (p = 0.47), rs2430366 (p = 0.45) or rs2254320 (p = 0.46). Haplotype analysis did not reveal any significant difference. In conclusion, genetic variation within FBLN5 is unlikely to play any role in the development of AAA.