Michiel T. Voûte

Calcification of the abdominal aorta as an independent predictor of cardiovascular events: a meta-analysis

Context Abdominal aortic calcification (AAC) is a common finding in patients with atherosclerosis. Objective The aim of this study was to demonstrate the incremental value of AAC in predicting long term cardiovascular (CV) outcome by conducting a meta-analysis of observational studies. Data sources MEDLINE and Cochrane databases. Study selection Longitudinal studies with at least 2 years of follow-up, reporting the influence of AAC on CV outcome of general population patients. Data extraction Four separate end points—coronary events, cerebrovascular events, all CV events and CV related death—were tested for their relationship with AAC at baseline, using weighted random effects meta-analysis. Heterogeneity was calculated using Q and I2 statistic tests. Publication bias was assessed by funnel plot symmetry and trim and fill methods. The importance of calcium quantification was also explored (sensitivity analysis). Results 10 studies were included. An increased relative risk (RR) was found for all end points: for coronary events (five studies, n=11250) 1.81 (95% CI 1.54 to 2.14); for cerebrovascular events (four studies, n=9736) 1.37 (1.22 to 3.54); for all CV events (four studies, n=4960) 1.64 (1.24 to 2.17); and for CV death (three studies, n=4986) 1.72 (1.03 to 2.86). Analysis of studies presenting results in categories (no/minimal, moderate and severe calcification) revealed a stepwise increase in the RR for all end points. Significant heterogeneity was found in the included studies. Sources of heterogeneity were identified in the publication date, duration of follow-up, and mean age and gender differences in the included patient cohorts. Conclusion Existing data suggest that AAC is a strong predictor of CV related events or death in the general population. The predictive impact is greater in more calcified aortas. The generalisability of the meta-analysis is limited by heterogeneity in the coronary events, all CV events and CV death end points.

Stent graft composition plays a material role in the postimplantation syndrome.

OBJECTIVE In patients undergoing endovascular aneurysm repair (EVAR), the postimplantation syndrome (PIS), comprising fever and inflammation, occurs frequently. The cause of PIS is unclear, but graft composition and acute thrombus formation may play a role. The objective of this study was to evaluate these possible causes of the inflammatory response after EVAR. METHODS One hundred forty-nine patients undergoing elective EVAR were included. Implanted stent grafts differed mainly in the type of fabric used: either woven polyester (n=82) or expanded polytetrafluorethylene (ePTFE; n=67). Tympanic temperature and C-reactive protein (CRP) were assessed daily during hospitalization. PIS was defined as the composite of a body temperature of ≥38°C coinciding with CRP>10 mg/L. Besides graft composition, the size of the grafts and the volume of new-onset thrombus were calculated using dedicated software, and results were correlated to PIS. RESULTS Implantation of grafts made of polyester was associated with higher postoperative temperature (P<.001), CRP levels (P<.001), and incidence of PIS (56.1% vs 17.9%; P<.001) compared to ePFTE. After multivariate analysis, woven polyester stent grafts were independently associated with an increased risk of PIS (hazard ratio, 5.6; 95% confidence interval, 1.6-19.4; P=.007). Demographics, amount of graft material implanted, or new-onset thrombus had no association with PIS. CONCLUSIONS The composition of stent grafts may play a material role in the incidence of postimplantation syndrome in patients undergoing EVAR. Implantation of stent grafts based on woven polyester was independently associated with a stronger inflammatory response.

Vitamin D Deficiency may be an Independent Risk Factor for Arterial Disease

OBJECTIVES The aim of this study was to assess the vitamin D status in patients with occlusive or aneurysmatic arterial disease in relation to clinical cardiovascular risk profiles and markers of atherosclerotic disease. METHODS We included 490 patients with symptomatic peripheral arterial disease (PAD, n = 254) or aortic aneurysm (n = 236). Cardiovascular risk factors and comorbidities carotid intima-media thickness (CIMT), ankle-brachial index (ABI), serum high-sensitive C-reactive protein (hs-CRP) and vitamin D were assessed. Patients were categorised into severely (≤25 nmol l(-1)) or moderately (26-50 nmol l(-1)) vitamin D deficient, vitamin D insufficient (51-75 nmol l(-1)) or vitamin D sufficient (>75 nmol l(-1)). RESULTS Overall, 45% of patients suffered from moderate or severe vitamin D deficiency. The prevalence of vitamin D deficiency was similar in patients with PAD and those with an aortic aneurysm. Low levels of vitamin D were associated with congestive heart failure and cerebrovascular disease. Adjusting for clinical cardiovascular risk factors, multivariable regression analyses showed that low vitamin D status was associated with higher CIMT (P = 0.001), lower ABI (P < 0.001) and higher hs-CRP (P = 0.022). CONCLUSIONS The current study shows a strong association between low vitamin D status and arterial disease, independent of traditional cardiovascular risk factors and irrespective of the type of vascular disease, that is, occlusive or aneurysmatic disease.

Clinical outcome and morphologic analysis after endovascular aneurysm repair using the Excluder endograft

OBJECTIVE Long-term follow-up after endovascular aneurysm repair (EVAR) is very scarce, and doubt remains regarding the durability of these procedures. We designed a retrospective cohort study to assess long-term clinical outcome and morphologic changes in patients with abdominal aortic aneurysms (AAAs) treated by EVAR using the Excluder endoprosthesis (W. L. Gore and Associates, Flagstaff, Ariz). METHODS From 2000 to 2007, 179 patients underwent EVAR in a tertiary institution. Clinical data were retrieved from a prospective database. All patients treated with the Excluder endoprosthesis were included. Computed tomography angiography (CTA) scans were retrospectively analyzed preoperatively, at 30 days, and at the last follow-up using dedicated tridimensional reconstruction software. For patients with complications, all remaining CTAs were also analyzed. The primary end point was clinical success. Secondary end points were freedom from reintervention, sac growth, types I and III endoleak, migration, conversion to open repair, and AAA-related death or rupture. Neck dilatation, renal function, and overall survival were also analyzed. RESULTS Included were 144 patients (88.2% men; mean age, 71.6 years). Aneurysms were ruptured in 4.9%. American Society of Anesthesiologists classification was III/IV in 61.8%. No patients were lost during a median follow-up of 5.0 years (interquartile range, 3.1-6.4; maximum, 11.2 years). Two patients died of medical complications ≤ 30 days after EVAR. The estimated primary clinical success rates at 5 and 10 years were 63.5% and 41.1%, and secondary clinical success rates were 78.3% and 58.3%, respectively. Sac growth was observed in 37 of 142 patients (26.1%). Cox regression showed type I endoleak during follow-up (hazard ratio, 3.74; P = .008), original design model (hazard ratio, 3.85; P = .001), and preoperative neck diameter (1.27 per mm increase, P = .006) were determinants of sac growth. Secondary interventions were required in 32 patients (22.5%). The estimated 10-year rate of AAA-related death or rupture was 2.1%. Overall life expectancy after AAA repair was 6.8 years. CONCLUSIONS EVAR using the Excluder endoprosthesis provides a safe and lasting treatment for AAA, despite the need for maintained surveillance and secondary interventions. At up to 11 years, the risk of AAA-related death or postimplantation rupture is remarkably low. The incidences of postimplantation sac growth and secondary intervention were greatly reduced after the introduction of the low-permeability design in 2004.

The influence of neck thrombus on clinical outcome and aneurysm morphology after endovascular aneurysm repair

OBJECTIVE This study investigated the influence of significant aneurysm neck thrombus in clinical and morphologic outcomes after endovascular aneurysm repair (EVAR). METHODS The patient population was derived from a prospective EVAR database from two university institutions in The Netherlands from 2004 to 2008. Patients with significant thrombus in the neck (>2 mm in thickness in at least >25% of circumference) were identified as the thrombus group and were compared with the remaining patients without neck thrombus (no-thrombus group), treated within the same period. The primary end point was clinical success. Secondary end points included technical success and rates of decline in renal function. Detailed morphologic analysis of the aortic neck was serially performed for the thrombus group patients to assess changes in thrombus volume. RESULTS The study included 389 patients: 43 (39 men; mean age of 72.3 years) met the criteria for the thrombus group; of these, 31 (72%) had significant thrombus in >50% of the aortic neck circumference, and 8 (19%) had circumferential thrombus >2-mm thick. Median follow-up was 3.34 years (interquartile range, 2.67-4.72). The estimated 5-year clinical success rate was 74% for the thrombus group and 62% for the no-thrombus group (P = .23). Endograft migration was more frequent in the thrombus group (P = .02). Multivariable Cox regression analysis showed a significant association between migration and use of a device without active fixation (hazard ratio, 4.9; 95% confidence interval, 1.31-18.23; P = .018) but not with the presence of neck thrombus (P = .063). No differences were found in the rates of decline in estimated glomerular filtration rate at 30 days and during follow-up between the thrombus and no-thrombus groups. The thrombus volume in the first 10 mm of aortic neck was progressively reduced over time until it was not measurable in most patients, resulting in complete circular attachment of the endograft to the vessel wall. CONCLUSIONS Our findings suggest that the presence of aneurysm neck thrombus has no significant influence on short-term and midterm EVAR 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.

Asymptomatic Low Ankle-Brachial Index in Vascular Surgery Patients: A Predictor of Perioperative Myocardial Damage

OBJECTIVES This study evaluated the prognostic value of asymptomatic low ankle-brachial index (ABI) to predict perioperative myocardial damage, incremental to conventional cardiac risk factors imbedded in cardiac risk indices (Revised Cardiac index and Adapted Lee index). MATERIALS AND METHODS Preoperative ABI measurements were performed in 627 consecutive vascular surgery patients (carotid artery or abdominal aortic aneurysm repair). An ABI<0.90 was considered abnormal. Patients with ABI>1.40 or (a history of) intermittent claudication were excluded. Serial troponin-T measurements were performed routinely before and after surgery. The main study endpoint was perioperative myocardial damage, the composite of myocardial ischaemia and infarction. Multivariate regression analyses, adjusted for conventional risk factors, evaluated the relation between asymptomatic low ABI and perioperative myocardial damage. RESULTS In total, 148 (23%) patients had asymptomatic low ABI (mean 0.73, standard deviation+/-0.13). Perioperative myocardial damage was recorded in 107 (18%) patients. Multivariate regression analyses demonstrated that asymptomatic low ABI was associated with an increased risk of perioperative myocardial damage (odds ratio (OR): 2.4, 95% CI: 1.4-4.2) CONCLUSIONS: This study demonstrated that asymptomatic low ABI has a prognostic value to predict perioperative myocardial damage in vascular surgery patients, incremental to risk factors imbedded in conventional cardiac risk indices.

Radial Force Measurements in Carotid Stents: Influence of Stent Design and Length of the Lesion

PURPOSE To assess the differences in radial force of carotid stents and whether the length of the lesion influences the measurements. MATERIALS AND METHODS Different models of tapered stents of similar size (length, 30 mm) were used. The tapered nitinol Acculink, Protégé, and Cristallo Ideale carotid artery stents and the straight, braided Elgiloy carotid Wallstent were compared. A measurement device consisting of three film loops along the stent body connected to aluminium rods with copper strain gauges was developed. Five stents of each type were deployed within 3-mm stenoses in simulated long (26 mm) and short (8 mm) stenoses. RESULTS In the short stenosis simulation, the greatest radial force was seen in the Protégé stent, at 3.14 N ± 0.45, followed by the Cristallo Ideale stent (1.73 N ± 0.51), Acculink (1.16 N ± 0.21), and Wallstent (0.84 N ± 0.10; P < .001). In the long stenosis simulation, peak radial force again was highest in the Protégé stent (1.67 N ± 0.37), but the Acculink stent was second (0.95 N ± 0.12) and the Wallstent third (0.80 N ± 0.06). The Cristallo Ideale stent, in contrast to the short stenosis simulation, produced the least radial force (0.44 N ± 0.13) in the long stenosis simulation (P = .001). CONCLUSIONS Radial forces exerted by carotid stents vary significantly among stent designs. Differences between stent types are dependent on the length of the stenosis. An understanding of radial force is necessary for a well-considered choice of stent type in each individual patient.

A Randomised Study of Perioperative Esmolol Infusion for Haemodynamic Stability during Major Vascular Surgery; Rationale and Design of DECREASE-XIII

OBJECTIVES This article describes the rationale and design of the DECREASE-XIII trial, which aims to evaluate the potential of esmolol infusion, an ultra-short-acting beta-blocker, during surgery as an add-on to chronic low-dose beta-blocker therapy to maintain perioperative haemodynamic stability during major vascular surgery. DESIGN A double-blind, placebo-controlled, randomised trial. MATERIALS & METHODS A total of 260 vascular surgery patients will be randomised to esmolol or placebo as an add-on to standard medical care, including chronic low-dose beta-blockers. Esmolol is titrated to maintain a heart rate within a target window of 60-80 beats per minute for 24 h from the induction of anaesthesia. Heart rate and ischaemia are assessed by continuous 12-lead electrocardiographic monitoring for 72 h, starting 1 day prior to surgery. The primary outcome measure is duration of heart rate outside the target window during infusion of the study drug. Secondary outcome measures will be the efficacy parameters of occurrence of cardiac ischaemia, troponin T release, myocardial infarction and cardiac death within 30 days after surgery and safety parameters such as the occurrence of stroke and hypotension. CONCLUSIONS This study will provide data on the efficacy of esmolol titration in chronic beta-blocker users for tight heart-rate control and reduction of ischaemia in patients undergoing vascular surgery as well as data on safety parameters.

Safety of fluvastatin in patients undergoing high-risk non-cardiac surgery

Importance of the field: In patients undergoing vascular surgery there is a high incidence of adverse cardiac events, due to sudden coronary plaque rupture. The non-lipid lowering or pleiotropic effects of statins can help reduce adverse cardiovascular events associated with vascular surgery. Areas covered in this review: The evidence for perioperative use of fluvastatin, as well as other statins, in high-risk surgery patients is summarized in this review. Data on pharmacokinetics and metabolism is presented, together with considerations on possible drug interactions in the perioperative period. What the reader will gain: The reader will gain a comprehensive understanding of the existing safety and efficacy data for fluvastatin and other statins in the perioperative period. The practical considerations of perioperative fluvastatin therapy will be presented, including potential side-effects and management of the early non-oral phase immediately post surgery. Finally, advice on when to initiate therapy and safety recommendations are offered. Take home message: In patients scheduled for high-risk vascular surgery, fluvastatin improves postoperative outcome, reducing the incidence of myocardial damage by ∼ 50% in the first 30 days following vascular surgery. In comparison with placebo, fluvastatin was not associated with a rise in liver enzymes or creatine kinase levels. To bridge the non-oral phase, an extended-release formula is recommended.