Patient Specific Wall Stress Analysis and Mechanical Characterization of Abdominal Aortic Aneurysms Using 4D Ultrasound.

OBJECTIVES: The aim of this study was to perform wall stress analysis (WSA) using 4D ultrasound (US) in 40 patients with an abdominal aortic aneurysm (AAA). The geometries and wall stress results were compared with computed tomography (CT) in seven patients. Additionally, the WSA models were calibrated using 4D motion estimation, resulting in patient specific material parameters that were compared among patients. METHODS: 4D-US images were acquired for 40 patients (AAA diameter 27-52 mm). Patient specific AAA geometries and wall motion were extracted from the 4D-US. WSA was performed and corresponding patient specific material properties were derived. For seven patients, CT data were available and analyzed for geometry and wall stress comparison. RESULTS: The 4D-US based 99th percentile wall stress ranged from 198 to 390 kPa. Regression analysis showed no significant relation between wall stress and diameter of the AAA. The similarity indices between US and CT were very good and ranged between 0.90 and 0.96, and the 25th, 50th, 75th, and 95th percentile wall stresses of the US and CT data were in agreement. The characterized patient specific shear modulus had a median of 1.1 MPa (interquartile range, 0.7-1.4 MPa). Based on the maximum AAA diameter, the AAAs were divided in a small, medium, and large diameter groups. The largest AAAs revealed an increased wall stiffness compared with the smallest AAAs. CONCLUSIONS: 4D ultrasound is applicable for wall stress analysis of AAAs, and offers the opportunity to perform wall stress analysis over time, also for AAAs who do not qualify for a CT or magnetic resonance imaging. Moreover, the patient specific material properties can be determined, which could possibly improve risk assessment.

Endovascular Treatment of Ruptured Abdominal Aortic Aneurysms with Hostile Aortic Neck Anatomy.

OBJECTIVE: To compare the mid-term results of endovascular aortic aneurysm repair (EVAR) for ruptured abdominal aortic aneurysms (RAAAs) in patients with favourable aortic neck anatomy (FNA) and hostile aortic neck anatomy (HNA). METHODS: Patients treated for a RAAA in a high volume endovascular centre in the Netherlands between February 2009 and January 2014 were identified retrospectively and divided into two groups based on aortic neck anatomy, FNA and HNA. HNA was defined as RAAA with a proximal neck of <10 mm, or a proximal neck of 10-15 mm with a suprarenal angulation (α) >45° and/or an infrarenal angulation (ß) >60°, or a proximal neck of >15 mm combined with α >60° and/or ß >75°. Patient demographics, procedure details, 30 day and 1 year outcomes were recorded. RESULTS: Of 39 included patients, 17 (44%) had HNA. Technical success was 100% for FNA and 88% for HNA (p = .184). There were no type IA endoleaks on completion angiography in either group; however, more adjunctive procedures were necessary for intra-operative type IA endoleaks in the HNA group (24% vs. 0%, p = .029). Thirty day mortality rates were comparable, FNA 14% vs. HNA 12% (p = 1.000). There were no statistically significant differences at 1 year follow up in type I endoleaks, secondary endovascular procedures, or all cause mortality. CONCLUSION: Emergency EVAR provides excellent results for treatment of RAAA patients with both FNA and HNA. EVAR in RAAAs with HNA is technically feasible and safe in experienced endovascular centres. Article history.

Beneficial Effects of Pre-operative Exercise Therapy in Patients with an Abdominal Aortic Aneurysm: A Systematic Review.

OBJECTIVE/BACKGROUND: The impact of post-operative complications in abdominal aortic aneurysm (AAA) surgery is substantial, and increases with age and concomitant co-morbidities. This systematic review focuses on the possible effects of pre-operative exercise therapy (PET) in patients with AAA on post-operative complications,aerobic capacity, physical fitness, and recovery. METHODS: A systematic search on PET prior to AAA surgery was conducted. The methodological quality of the included studies was rated using the Physiotherapy Evidence Database scale. The agreement between the reviewers was assessed with Cohen's kappa. RESULTS: Five studies were included, with a methodological quality ranging from moderate to good. Cohen's kappa was 0.79. Three studies focused on patients with an AAA (without indication for surgical repair) with physical fitness as the outcome measure. One study focused on PET in patients awaiting AAA surgery and one study focused on the effects of PET on post-operative complications, length of stay, and recovery. CONCLUSION: PET has beneficial effects on various physical fitness variables of patients with an AAA. Whether this leads to less complications or faster recovery remains unclear. In view of the large impact of post-operative complications, it is valuable to explore the possible benefits of a PET program in AAA surgery.

Editor's choice--Use of disposable radiation-absorbing surgical drapes results in significant dose reduction during EVAR procedures.

OBJECTIVES: Because of the increasing number of interventional endovascular procedures with fluoroscopy and the corresponding high annual dose for interventionalists, additional dose-protecting measures are desirable. The purpose of this study was to evaluate the effect of disposable radiation-absorbing surgical drapes in reducing scatter radiation exposure for interventionalists and supporting staff during an endovascular aneurysm repair (EVAR) procedure. MATERIALS: This was a randomized control trial in which 36 EVAR procedures were randomized between execution with and without disposable radiation-absorbing surgical drapes (Radpad: Worldwide Innovations & Technologies, Inc., Kansas City, US, type 5511A). Dosimetric measurements were performed on the interventionalist (hand and chest) and theatre nurse (chest) with and without the use of the drapes to obtain the dose reduction and effect on the annual dose caused by the drapes. RESULTS: Use of disposable radiation-absorbing surgical drapes resulted in dose reductions of 49%, 55%, and 48%, respectively, measured on the hand and chest of the interventionalist and the chest of the theatre nurse. CONCLUSIONS: The use of disposable radiation-absorbing surgical drapes significantly reduces scatter radiation exposure for both the interventionalist and the supporting staff during EVAR procedures.

Standardized definitions and clinical endpoints in trials investigating endovascular repair of aortic dissections.

OBJECTIVES: Endovascular therapy is a rapidly expanding option for the treatment of patients with aortic dissection (AD) and various studies have been published. These trials, however, are often difficult to interpret and compare because they do not utilize uniform clinical endpoint definitions. METHODS: The DEFINE Group is a collaborative effort of an ad hoc multidisciplinary team from various specialties involved in AD therapy in Europe and the United States. DEFINE's goal was to arrive at a broad based consensus for baseline and endpoint definitions in trials for endovascular therapy of various vascular pathologies. In this project, which started in December 2006, the individual team members reviewed the existing pertinent literature. Following this, a series of telephone conferences and face-to-face meetings were held to agree upon definitions. Input was also obtained from regulatory (United States Food and Drug Administration) and industry (device manufacturers with an interest in peripheral endovascular revascularization) stakeholders, respectively. RESULTS: These efforts resulted in the present document containing proposed baseline and endpoint definitions for clinical and morphological outcomes. Although the consensus has inevitably included certain arbitrary consensus choices and compromises, adherence to these proposed standard definitions would provide consistency across future trials, thereby facilitating evaluation of clinical effectiveness and safety of various endovascular revascularization techniques. CONCLUSIONS: This current document is based on a broad based consensus involving relevant stakeholders from the medical community, industry and regulatory bodies. It is proposed that the consensus document may have value for study design of future clinical trials in endovascular AD therapy as well as for regulatory purposes.

Challenging the evidence for pre-emptive coil embolisation of the internal iliac artery during endovascular aneurysm repair.

OBJECTIVES: We retrospectively analysed the results of a strategy in which coverage of the internal iliac artery (IIA) during endovascular aneurysm repair (EVAR) was routinely performed without coil embolisation. METHODS: From January 2010 until May 2012, 32 patients (96.9% men; mean age 73.0 years, range 52-89 years) underwent EVAR with stent grafts extended into the external iliac artery (EIA), all without prior coil embolisation. Aneurysm morphology was determined on preoperative computed tomography (CT) images. During follow-up, patients were interviewed about buttock claudication, and the occurrence of endoleaks and evolution of aneurysm diameter were recorded. RESULTS: At baseline, the mid-common iliac artery (CIA) diameter was 33.5 ± 16.8 mm and seven patients presented with ruptured aneurysms. Mean follow-up was 14.3 ± 7.4 months. There were eight deaths, none related to IIA coverage. Buttock claudication occurred in seven (22.6%) patients, which persisted after 6 months in two cases of bilateral IIA coverage. No Type-I or -II endoleaks occurred related to IIA coverage. Aneurysm growth was not observed. CONCLUSION: Endovascular treatment of aortoiliac and iliac aneurysm without pre-emptive coil embolisation of the IIA appears safe and effective. No IIA-related endoleaks or re-interventions occurred in our series. This approach saves operating time, contrast load and costs and may reduce complications. However, a larger population and longer follow-up is required to confirm our findings.

No differences in perioperative outcome between symptomatic and asymptomatic AAAs after EVAR: an analysis from the ENGAGE Registry.

AIM: This study aimed to compare the differences in perioperative outcome after endovascular repair of symptomatic abdominal aneurysms (S-AAAs) and elective non-symptomatic AAAs (E-AAAs). Data from the ENGAGE Registry were used for the analysis. METHODS: Between March 2009 and December 2010, 1200 AAA patients were enrolled from 79 sites in 30 countries and treated with an Endurant Stent Graft. S-AAAs defined as AAAs accompanied by abdominal or back pain, without rupture, were present in 185 (15.4%) patients and E-AAAs in 1015 (84.6%) patients. Multivariate logistic regression was used to compare results. RESULTS: At baseline, E-AAA patients had larger aneurysms on average (P = 0.006) and scored higher ASA classification more often (P = 0.001). Further analyses were corrected for baseline differences. Operation time and technical success were comparable, and S-AAAs were admitted to the Intensive Care Unit (ICU) as often as E-AAAs (35.7% vs. 33.4%, P = 0.479). Post-operative hospitalisation was similar (4.83 ± 5.29 in E-AAAs and 4.37 ± 3.49 in S-AAAs, P = 0.360). No differences in the occurrence of major adverse events, including mortality, within the 30-day post-implantation were seen between S-AAA and E-AAA patients, respectively, 3.2% and 4.2% (P = 0.572). CONCLUSION: With contemporary devices and technical proficiency, there is no difference in outcome between symptomatic AAA and elective non-symptomatic AAA patients if treated with endovascular techniques.

Early results from the ENGAGE registry: real-world performance of the Endurant Stent Graft for endovascular AAA repair in 1262 patients.

OBJECTIVE: The ENGAGE registry was undertaken to examine the real-world outcome after endovascular abdominal aortic aneurysm (AAA) repair (EVAR) with the Endurant Stent Graft in a large, contemporary, global series of patients. METHODS: From March 2009 to April 2011, 1262 AAA patients (89.6% men; mean age 73.1 years, range 43-93 years) were enrolled from 79 sites in 30 countries and treated with Endurant. Results are described following the reporting standards for EVAR. Follow-up data were tabulated for all 1262 patients at a 30-day follow-up and for the first 500 patients at a 1-year follow-up. RESULTS: Intra-operative technical success was achieved in 99.0% of cases. Within 30 days, adverse events were reported in 3.9% of patients, including a 1.3% mortality rate. Type-I or -III endoleaks were identified in 1.5% of cases. Estimated overall survival, aneurysm-related survival and freedom from secondary interventions at 1 year were 91.6%, 98.6% and 95.1%, respectively. At 1 year, aneurysm size increased ≥ 5 mm in 2.8% and decreased ≥ 5 mm in 41.3% of cases. CONCLUSION: Early results from this real world, global experience are promising and indicate that endovascular AAA repair with the Endurant Stent Graft is safe and effective across different geographies and standards of practice. Longer-term follow-up is necessary to assess durability of these results.

Treatment of post-implantation aneurysm growth by laparoscopic sac fenestration: long-term results.

OBJECTIVES: Sac growth after endovascular aneurysm repair (EVAR) is an important finding, which may influence prognosis. In case of a type II endoleak or endotension, clipping of side branches and subsequent sac fenestration has been presented as a therapeutic alternative. The long-term clinical efficacy of this procedure is unknown. METHODS: The study included eight patients who underwent laparoscopic aortic collateral clipping and sac fenestration for enlarging aneurysms following EVAR. Secondary interventions and clinical outcome were retrieved from hospital records. Sac behaviour was evaluated measuring volumes on periodical computed tomography angiography (CTA) imaging using dedicated software. RESULTS: Follow-up had a median length of 6.6 (range 0.6-8.6) years. During this time, only three patients successfully achieved durable aneurysm shrinkage (n = 2) or stability (n = 1). The remaining patients suffered persistent (n = 2) or recurrent sac growth (n = 3), all regarded as failure of fenestration. A total of six additional interventions were performed, comprising open conversion (n = 2), relining (n = 1) and implantation of iliac extensions (n = 3). All additional interventions were successful at arresting further sac growth during the remainder of follow-up. CONCLUSIONS: Despite being a less invasive alternative to conversion and open repair, the long-term outcome of sac fenestration is unpredictable and additional major procedures were often necessary to arrest sac growth.

The impact of gender on prognosis after non-cardiac vascular surgery.

OBJECTIVES: The objective was to evaluate the impact of gender on long-term survival of patients who underwent non-cardiac vascular surgery. DESIGN, MATERIAL AND METHODS: Our prospectively collected data contained information on 560 patients undergoing carotid endarterectomy (CEA), 923 elective abdominal aortic aneurysm repairs (AAA) and 1046 lower limb reconstructions (LLR). Patient characteristics and long-term mortality of women were compared to that of men. Kaplan-Meier (KM) survival curves were constructed for men and women, on which we superimposed age- and sex-matched KM survival curves of the general population. Cox proportional hazards regression was used to identify risk factors for mortality. RESULTS: Men in the CEA group had statistically significant higher all-cause mortality, hazard rate ratio (HRR) 1.41 (95% CI 1.01-1.98) No differences in mortality between the genders were observed in the AAA and LLR groups. Overall, men had more co-morbidities but received more disease-specific medication compared to women. Women retained their higher life expectancy after CEA but lost it in the AAA and LLR groups. CONCLUSION: Women retain their higher life expectancy after CEA; however, after AAA repair and LLR, this advantage is lost. Both men and women received too little disease-specific medication, but women were worse off.

EVAR suitability is not a predictor for early and midterm mortality after open ruptured AAA repair.

OBJECTIVE: The reported mortality reduction of emergency endovascular aneurysm repair (eEVAR) compared with open repair in patients with a ruptured abdominal aortic aneurysm (rAAA), as observed in observational studies, might be flawed by selection bias based on anatomical suitability for eEVAR. In the present study, we compared mortality in EVAR suitable versus non-EVAR-suitable patients with a ruptured AAA who were all treated with conventional open repair. MATERIALS AND METHODS: In all patients presenting with a suspected rAAA, computed tomography angiography (CTA) scanning was performed. All consecutive patients with a confirmed rAAA on preoperative CTA scan and treated with open repair between April 2002 and April 2008 were included. Anatomical suitability for eEVAR was determined by two blinded independent reviewers. Outcomes evaluated were mortality (intra-operative, 30-day, and 6-month), morbidity, complications requiring re-intervention and length of hospital stay. RESULTS: A total of 107 consecutive patients presented with a rAAA and underwent preoperative CTA scanning. In 25 patients, eEVAR was performed. In the 82 patients who underwent open repair, CTA showed an EVAR-suitable rAAA in 33 patients (41.8%) and a non-EVAR-suitable rAAA in 49 patients. Thirty-day and 6-month mortality rate was 15/33 (45.5%; 95% confidence interval (CI) 28.1-63.7) and 18/33 (54.5%; 95% CI 36.4-71.9) in the EVAR-suitable group versus 24/49 (49.0%; 95% CI 34.4-63.7) (P=0.75) and 29/49 (59.2%; 95% CI 44.2-73.0) (P=0.68) in the non-EVAR-suitable group, respectively. CONCLUSIONS: The present study suggests that anatomical suitability for EVAR is not associated with lower early and midterm mortality in patients treated with open ruptured AAA repair. Therefore, the reported reduction in mortality between eEVAR and open repair is unlikely due to selection bias based on anatomical AAA configuration.

Vascular complications of Q-fever infections.

INTRODUCTION: Coxiella burnetii is a strict intracellular pathogen causing Q fever, a worldwide zoonosis with an extensive animal reservoir. Chronic Q fever infections are frequently associated with cardiovascular complications, mainly endocarditis, and also aortic aneurysms and vascular-graft infection. We present four cases of chronic Q fever infections and associated vascular complications, and review the literature to identify major symptoms and assess the prevalence, treatment and outcome in these challenging patients. MATERIALS AND METHODS: The demographic and clinical data of four patients presenting at our unit were analysed. PubMed was searched to identify articles describing patients with chronic Q-fever-associated vascular complications. RESULTS: Combining our own with the published experience, 58 cases (49 male) of chronic Q-fever-associated vascular complications were identified. The average age of the patients was 64 years (range: 30-83 years). As many as 26 patients had vascular graft infections (25 Dacron/polytetrafluoroethylene (PTFE), one homograft) and 32 had infected aneurysms. The majority of these patients presented with fever (n = 40) and/or pain (n = 43). Weight loss and fatigue were seen in 25 and 14 patients, respectively. Aneurysm rupture, aorto-enteric fistulae and lower-limb embolisation were seen in nine, four and four patients, respectively. Concurrent endocarditis was seen in two patients, whereas, for 15 cases, this information was not available. Patients were treated with antibiotics for an average of 23 months (range 1-54 months). Treatment of infected vascular segments was described in 50 patients. Ten patients were treated conservatively whilst 40 underwent resection of the infected vessel and reconstruction with a graft. Major surgical complications (graft infection, n = 3;aorto-enteric fistula, n = 2; bleeding, n = 1; anastomotic leakage, n = 1; aortic dissection, n = 1; vertebral osteomyelitis, n = 3; graft thrombosis, n = 1; renal failure, n = 2; and pneumonia, n = 1) were reported in 11 cases (21%) and were not specified in 13. The overall mortality was 24% (14/58). Seven (18%) surgically treated patients died. Six of them died within 6 months of surgery and one patient at 3 years' follow-up. Seven out of 10 of the conservatively treated patients died within 3 years of diagnosis. CONCLUSION: Aneurysms associated with Q-fever infections tend to be complicated, requiring challenging surgical corrections, and long-term antibiotic treatment. Major complications and mortality rates are significant, especially in conservatively treated patients.

Endovascular abdominal aortic aneurysm repair in women.

The objective of this review is to establish the role of endovascular aortic aneurysm repair (EVAR) in women. A step by step approach is taken looking at sex and gender differences in epidemiology, pathogenesis and natural history. We then proceed to discuss the results from the three randomized controlled trials comparing EVAR to open repair. Finally, sex-specific secondary prevention, risk factor management and medication, is discussed. Women seem to have higher mortality and more complications after EVAR. Risk factors such as diabetes and hypertension are associated with worse outcome in women compared to men. The role of EVAR in women is poorly investigated and its definite role remains to be determined. Aggressive treatment of risk factors and the optimisation of medication in women are indicated and deserve more attention in clinical practice and future research.

Systematic review and meta-analysis of sex differences in outcome after intervention for abdominal aortic aneurysm.

BACKGROUND: The aim of this study was to assess possible differences in mortality between men and women with an abdominal aortic aneurysm (AAA) treated either by elective repair or following aneurysm rupture. METHODS: A systematic literature search was performed using the MEDLINE, Cochrane and Embase databases. Data were analysed by means of bivariate random-effects meta-analysis. Data were pooled and odds ratios (ORs) calculated for women compared with men. RESULTS: Sixty-one studies (516 118 patients) met the predetermined inclusion criteria. Twenty-six reported on elective open AAA repair, 21 on elective endovascular repair, 25 on open repair for ruptured AAA and one study on endovascular repair for ruptured AAA. Mortality rates for women compared with men were 7.6 versus 5.1 per cent (OR 1.28, 95 per cent confidence interval (c.i.) 1.09 to 1.49) for elective open repair, 2.9 versus 1.5 per cent (OR 2.41, 95 per cent c.i. 1.14 to 5.15) for elective endovascular repair, and 61.8 versus 42.2 per cent (OR 1.16, 95 per cent c.i. 0.97 to 1.37) in the group that had open repair for rupture. The group that had endovascular repair for ruptured AAA was too small for meaningful analysis. CONCLUSION: Women with an AAA had a higher mortality rate following elective open and endovascular repair.

The influence of wall stress on AAA growth and biomarkers.

OBJECTIVES: This study investigated the relation between abdominal aortic aneurysm (AAA) wall stress, AAA growth rate and biomarker concentrations. With increasing wall stress, more damage may be caused to the AAA wall, possibly leading to progression of the aneurysm and reflection in up- or downregulation of specific circulating biomarkers. Levels of matrix metalloproteinase-9, tissue inhibitor of matrix metalloproteinase-1, C-reactive protein and alpha 1-antitrypsin were therefore evaluated. METHODS: Thirty-seven patients (maximum AAA diameter 41-55mm) with two, three or four consecutive computed tomography angiography (CTA) scans were prospectively included. Diameter growth rate in mm/year was determined between each pair of two sequential CTA scans. AAA wall stress was computed by finite element analysis, based on the first of the two sequential CTA scans only (n=69 pairs). Biomarker information was determined in 46 measurements in 18 patients. The relation between AAA diameter and wall stress was determined and the AAA's were divided into three equally sized groups (relative low, medium and high stress). Growth rate and biomarker concentrations were compared between these groups. Additionally, correlation coefficients were computed between absolute wall stress, AAA growth and biomarker concentrations. RESULTS: A relative low AAA wall stress was associated with a lower aneurysm growth rate. Growth rate was also positively related to MMP-9 plasma concentration (r=0.32). The average MMP-9 and CRP concentrations increased with increasing degrees of relative wall stress, although the absolute and relative wall stress did not correlate with any of the biomarkers. CONCLUSION: Although lower relative wall stress was associated to a lower AAA growth rate, no relation was found between biomarker concentrations and wall stress. Future research may focus on more and extensive biomarker measurements in relation to AAA wall stress.

Predicting patient-specific expansion of abdominal aortic aneurysms.

OBJECTIVE: Local anatomy and the patient's risk profile independently affect the expansion rate of an abdominal aortic aneurysm. We describe a hybrid method that combines finite element modelling and statistical methods to predict patient-specific aneurysm expansion. METHODS: The 3-D geometry of the aneurysm was imaged with computed tomography. We used finite element methods to calculate wall stress and aneurysm expansion. Expansion rate was adjusted by risk factors obtained from a database of 80 patients. Aneurysm diameters predicted with and without the risk profiles were compared with diameters measured with ultrasound for 11 patients. RESULTS: For this specific group of patients, local anatomy contributed 62% and the risk profile 38% to the aneurysmal expansion rate. Predictions with risk profiles resulted in smaller root mean square errors than predictions without risk profiles (2.9 vs. 4.0 mm, p < 0.01). CONCLUSIONS: This hybrid approach predicted aneurysmal expansion for a period of 30 months with high accuracy.

Epidemiology, aetiology, risk of rupture and treatment of abdominal aortic aneurysms: does sex matter?

OBJECTIVES: To unravel the extent to which gender plays a role in the epidemiology, aetiology, risk of rupture and treatment of abdominal aortic aneurysms (AAAs) and to give an overview of these factors. DESIGN, MATERIALS AND METHODS: A literature review was performed in the Medline database and Cochrane Library for gender-specific articles on epidemiology, aetiology, risk of rupture and treatment of AAAs. RESULTS: Our literature review suggests that the prevalence of AAA in women is underestimated. Regarding aetiology, an oestrogen-mediated reduction in macrophage MMP-9 production seems to be an important mechanism causing gender-related differences in AAA development. We found consensus in the literature that women run a greater risk of rupture compared to men under the current management rules for AAAs. Their treatment mortality also seems to be higher for both elective and ruptured repair. CONCLUSIONS: Gender-specific guidelines should be put into place for the management of AAAs and awareness for this disease should be increased, both in women themselves and in their doctors.

Unmixing multi-spectral photoacoustic sources in human carotid plaques using non-negative independent component analysis.

Multi-spectral photoacoustic imaging (MSPAI) is promising for morphology assessment of carotid plaques; however, obtaining unique spectral characteristics of chromophores is cumbersome. We used MSPAI and non-negative independent component analysis (ICA) to unmix distinct signal sources in human carotid plaques blindly. The feasibility of the method was demonstrated on a plaque phantom with hemorrhage and cholesterol inclusions, and plaque endarterectomy samples ex vivo. Furthermore, the results were verified with histology using Masson's trichrome staining. Results showed that ICA could separate recent hemorrhages from old hemorrhages. Additionally, the signatures of cholesterol inclusion were also captured for the phantom experiment. Artifacts were successfully removed from signal sources. Histologic examinations showed high resemblance with the unmixed components and confirmed the morphologic distinction between recent and mature hemorrhages. In future pre-clinical studies, unmixing could be used for morphology assessment of intact human plaque samples.

Impaired glucose regulation, elevated glycated haemoglobin and cardiac ischaemic events in vascular surgery patients.

AIMS: Cardiac morbidity and mortality is high in patients undergoing high-risk surgery. This study investigated whether impaired glucose regulation and elevated glycated haemoglobin (HbA(1c)) levels are associated with increased cardiac ischaemic events in vascular surgery patients. METHODS: Baseline glucose and HbA(1c) were measured in 401 vascular surgery patients. Glucose < 5.6 mmol/l was defined as normal. Fasting glucose 5.6-7.0 mmol/l or random glucose 5.6-11.1 mmol/l was defined as impaired glucose regulation. Fasting glucose > or = 7.0 or random glucose > or = 11.1 mmol/l was defined as diabetes. Perioperative ischaemia was identified by 72-h Holter monitoring. Troponin T was measured on days 1, 3 and 7 and before discharge. Cardiac death or Q-wave myocardial infarction was noted at 30-day and longer-term follow-up (mean 2.5 years). RESULTS: Mean (+/- sd) level for glucose was 6.3 +/- 2.3 mmol/l and for HbA(1c) 6.2 +/- 1.3%. Ischaemia, troponin release, 30-day and long-term cardiac events occurred in 27, 22, 6 and 17%, respectively. Using subjects with normal glucose levels as the reference category, multivariate analysis revealed that patients with impaired glucose regulation and diabetes were at 2.2- and 2.6-fold increased risk of ischaemia, 3.8- and 3.9-fold for troponin release, 4.3- and 4.8-fold for 30-day cardiac events and 1.9- and 3.1-fold for long-term cardiac events. Patients with HbA(1c) > 7.0% (n = 63, 16%) were at 2.8-fold, 2.1-fold, 5.3-fold and 5.6-fold increased risk for ischaemia, troponin release, 30-day and long-term cardiac events, respectively. CONCLUSIONS: Impaired glucose regulation and elevated HbA(1c) are risk factors for cardiac ischaemic events in vascular surgery patients.