Jan D. Blankensteijn

Collected world and single center experience with endovascular treatment of ruptured abdominal aortic aneurysms

Background:Case and single center reports have documented the feasibility and suggested the effectiveness of endovascular aneurysm repair (EVAR) of ruptured abdominal aortic aneurysms (RAAAs), but the role and value of such treatment remain controversial. Objective:To clarify these we examined a collected experience with use of EVAR for RAAA treatment from 49 centers. Methods:Data were obtained by questionnaires from these centers, updated from 13 centers committed to EVAR treatment whenever possible and included treatment details from a single center and information on 1037 patients treated by EVAR and 763 patients treated by open repair (OR). Results:Overall 30-day mortality after EVAR in 1037 patients was 21.2%. Centers performing EVAR for RAAAs whenever possible did so in 28% to 79% (mean 49.1%) of their patients, had a 30-day mortality of 19.7% (range: 0%–32%) for 680 EVAR patients and 36.3% (range: 8%–53%) for 763 OR patients (P < 0.0001). Supraceliac aortic balloon control was obtained in 19.1% ± 12.0% (±SD) of 680 EVAR patients. Abdominal compartment syndrome was treated by some form of decompression in 12.2% ± 8.3% (±SD) of these EVAR patients. Conclusion:These results indicate that EVAR has a lower procedural mortality at 30 days than OR in at least some patients and that EVAR is better than OR for treating RAAA patients provided they have favorable anatomy; adequate skills, facilities, and protocols are available; and optimal strategies, techniques, and adjuncts are employed.

Preoperative Sizing of Grafts for Transfemoral Endovascular Aneurysm Management: A Prospective Comparative Study of Spiral CT Angiography, Arteriography, and Conventional CT Imaging

PURPOSEnTo define the impact of spiral computed tomographic angiography (CTA) with image reconstruction on graft selection for Transfemoral Endovascular Aneurysm Management (TEAM) by comparing it to conventional computed tomography (CT) and contrast arteriography.nnnMETHODSnTwenty-one candidates for TEAM were included. The diameters of the superior and inferior aneurysm necks and lengths between the graft attachment sites were measured using the three imaging techniques. These measurements and their consequences on graft selection were studied.nnnRESULTSnThe difference in length sizing between spiral CTA and arteriography never exceeded 1 cm; however, lengths measured by conventional CT scanning resulted in underestimation of graft length in 91% of patients. Graft diameters were chosen too small in 62% of the patients when based on arteriographic diameter measurements. A graft of similar diameter was selected by spiral CTA and conventional CT scanning in 81% of the patients, while minor oversizing by conventional CT scanning was found in 14%.nnnCONCLUSIONSnNeither conventional CT scanning nor arteriography is adequate as a sole preoperative radiological investigation for TEAM graft sizing. Spiral CTA with image processing produces all information required for selection of the optimal graft size and should be regarded the method of first choice for this purpose.

Carotid endarterectomy for unstable and compelling neurologic conditions: Do results justify an aggressive approach?

PURPOSEnIn a retrospective study the outcome of 70 carotid endarterectomies (CEA) in 68 patients with neurologically unstable conditions or anatomically compelling findings on carotid angiography was examined to more accurately identify patients who might benefit from CEA in this setting.nnnMETHODSnOut of a total of 1734 CEAs performed from 1978 to 1992, five groups of patients were selected: group A, stroke in evolution with tight stenosis (n = 5); group C, crescendo transient ischemic attacks (CTIA) continuing despite heparin (n = 14); group D, CTIA (above criteria) ceasing with heparin (n = 21); and group E, anatomically compelling situation on carotid angiography (n = 13). Data collected included preoperative and postoperative Neurologic Event Severity Score (NESS), CHAT classification, arteriosclerosis risk factors, demographics, and long-term overall and transient ischemic attack/stroke-free survival rates.nnnRESULTSnRisk factors and demographics were similar in all groups. By NESS criteria the conditions of 97.3% of patients in the neurologically unstable groups A to C were improved or stabilized after operation, with one deterioration (2.7%). All patients in group B either stabilized or improved. In group D, one patients NESS deteriorated, resulting in 3.5% overall morbidity rate and no deaths for groups A to D. Follow-up showed an overall survival rate by Kaplan-Meier analysis equivalent to a matched control population, with 85% alive at 5 years. The cumulative TIA/stroke-free survival rate at 5 years was 75%.nnnCONCLUSIONSnIn this retrospective series, CEA performed for compelling or unstable neurologic findings carried low morbidity and mortality rates. Early aggressive surgical therapy of neurologically unstable patients may be warranted because our results improved on the anticipated natural history of the conditions studied. Further clarification of proper patient selection is necessary before this principle can be applied broadly.

Statin use is associated with reduced all-cause mortality after endovascular abdominal aortic aneurysm repair.

It has been shown that preoperative statin therapy reduces all-cause and cardiovascular mortality in patients undergoing major noncardiac vascular surgery. In this report, we investigated the influence of statin use on early and late outcome following endovascular abdominal aortic aneurysm repair (EVAR). The study population, consisting of patients collated in the EUROSTAR registry, was stratified in two groups according to statin use. Baseline characteristics between the two groups were compared by chi-square and Wilcoxon rank sum tests for discrete and continuous variables. The effects of statin use on outcomes after EVAR were analyzed by multivariate regression models. Of the 5,892 patients enrolled in the EUROSTAR registry, 731 (12.4%) patients used statins for hyperlipidemia. Statin users were younger, were more obese, and had a higher prevalence of diabetes, cardiovascular disease, and hypertension. After 5 years of follow-up, the cumulative survival rate was 77% for nonusers of statin versus 81% for statin users (p = .005). After adjustment for age and other risk factors, statin use was still an independent predictor of improved survival (p = .03). Our results revealed that statin prescription was more frequent in younger patients. However, when adjusted for age and medical risk factors, the use of statin in patients who underwent EVAR was still independently associated with reduced overall mortality.

Computed tomographic angiographic imaging of abdominal aortic aneurysms: implications for transfemoral endovascular aneurysm management

PURPOSEnTo describe anatomic features pertinent to patient selection and graft design for transfemoral endovascular aneurysm management (TEAM) of the infrarenal aorta using computed tomographic (CT) angiography.nnnMETHODSnA prospective noncomparative analysis of 102 spiral CT scans of the abdominal aorta of patients with abdominal aortic aneurysms was performed. From the original CT data set, slices were reconstructed perpendicular to the vessel axis (central lumen line) at a 10 mm interval. In these reconstructed slices, diameter measurements were performed. Vessel length was measured along the central lumen line. In each patient possibilities for TEAM were analyzed.nnnRESULTSnBecause of technical reasons, 36 scans were excluded from the analysis. Of the remaining 66 patients, 18 could potentially be treated with a bifurcated endovascular device. The infrarenal aortic diameter-to-iliac artery diameter ratio was less than 2 in most patients. The vessel segments judged to be adequate for endovascular graft anchoring had a noncylindrical shape in the majority of cases.nnnCONCLUSIONnOnly a minority of patients with abdominal aortic aneurysms can at this stage be treated with an endovascular graft. The ideal endovascular graft should be a combination of rigid and flexible components. The proximal and distal attachment systems should have some flexibility with an intrinsic maximum diameter while the midsection of the graft can be relatively rigid.

The role of infrarenal aortic side branches in the pathogenesis of endoleaks after endovascular aneurysm repair

AIMnTo investigate the relation between the number of preoperative patent side branches and the presence or absence of postoperative endoleaks, and to study the fate of patent branches after operation.nnnPATIENTS AND METHODSnThirty consecutive patients were included. Cine mode viewing of axial CT angiography images was applied to detect infrarenal aortic side branches. The position of side branches relative to the renal arteries, branch patency and run-off pathways were studied.nnnRESULTSnA total of 160 patent side branches were found. All patients had two or more patent side branches. A patent inferior mesenteric artery was found in 22/30 patients (73%). Postoperative CT scans revealed major endoleaks in five patients (16%) and minor endoleaks in eight (27%). There was no significant difference in the number of preoperative patent side branches in patients with a completely thrombosed aneurysm sac (five; range 2-8) compared to patients with postoperative endoleaks (six; range 3-9; p = 0.12). Backbleeding from patent side branches as the sole cause of endoleak was seen in one patient only (3.3%).nnnCONCLUSIONnPostoperative endoleaks are not related to the number of preoperative patent side branches. In patients without endoleaks, contrast enhancement of side branches was repeatedly seen in the vicinity of the aneurysm wall. Although close follow-up of these branches is warranted, they did not affect the outcome of endovascular aneurysm repair.

In-vivo imaging of changes in abdominal aortic aneurysm thrombus volume during the cardiac cycle.

Purpose: To evaluate in-vivo thrombus compressibility in abdominal aortic aneurysms (AAAs) to hopefully shed light on the biomechanical importance of intraluminal thrombus. Methods: Dynamic electrocardiographically-gated computed tomographic angiography was performed in 17 AAA patients (15 men; mean age 73 years, range 69–76): 11 scheduled for surgical repair and 6 under routine surveillance. The volumes of intraluminal thrombus, the lumen, and the total aneurysm were quantified for each phase of the cardiac cycle. Thrombus compressibility was defined as the percent change in thrombus volume between diastole and peak systole. Continuous data are presented as medians and interquartile ranges (IQR). Results: A substantial interpatient variability was observed in thrombus compressibility, ranging from 0.4% to 43.6% (0.2 to 13.5 mL, respectively). Both thrombus and lumen volumes varied substantially during the cardiac cycle. As lumen volume increased (5.2%, IQR 2.8%–8.8%), thrombus volume decreased (3.0%, IQR 1.0%–4.6%). Total aneurysm volume remained relatively constant (1.3%, IQR 0.4–1.9%). Changes in lumen volume were inversely correlated with changes in thrombus volume (r=–0.73; p=0.001). Conclusion: In-vivo thrombus compressibility varied from patient to patient, and this variation was irrespective of aneurysm size, pulse pressure, and thrombus volume. This suggests that thrombus might act as a biomechanical buffer in some, while it has virtually no effect in others. Whether differences in thrombus compressibility alter the risk of rupture will be the focus of future research.

Intraoperative determinants of infrainguinal bypass graft patency: a prospective study.

OBJECTIVESnTo evaluate a number of currently available methods for intraoperative assessment of infrainguinal bypass grafts (IBG) in terms of detecting technical errors and predicting graft failure.nnnDESIGNnProspective open clinical study.nnnMETHODSnForty-nine patients undergoing 54 consecutive IBG were studied. Intraoperatively, the following measurements were performed: distal pulse palpation (DPP), continuous wave Doppler (CWD), pulse volume recording (PVR), and ultrasonic volume flowmetry (UVF), followed by intraoperative angiography of the entire graft and runoff vessels. The outflow resistance was graded according to the guidelines of the Society for Vascular Surgery and International Society for Cardiovascular Surgery (SVS/ISCVS runoff score). Graft patency was determined noninvasively (PVR, colour Duplex) up to 12 months following surgery. Predictive values and likelihood ratios for the intraoperative tests in detecting a technical problem during the bypass procedure and in predicting early graft failure were calculated.nnnRESULTSnThere were five immediate revisions for problems detected intraoperatively. Angiography did not identify any additional problems but assisted in the correct location of the problems detected by the other tests. DPP and CWD were highly significant indicators of the need for revision with likelihood ratios for a positive test of 14.7 (p < 0.01) and 12.3 (p < 0.01) respectively. PVR did not achieve statistical significance in this respect. None of the intraoperative tests was a statistically significant predictor of early graft failure. The SVS/ISCVS runoff score, on the other hand, predicted early failure with a PPV of 33% (likelihood ratio for a positive test of 4.9, p < 0.05). None of the grafts with a perfect SVS/ISCVS runoff score (n = 39) failed in the first postoperative month.nnnCONCLUSIONSnSimple CWD insonation of graft and anastomoses is the best intraoperative indicator for technical inadequacies after IBG. Routine intraoperative angiography is not necessary and intraoperative anatomical imaging may be reserved for situations in which noninvasive documentation of technical success is absent. Contrary to the intraoperative haemodynamic test results, the SVS/ISCVS runoff score is a good predictor of early graft failure.

In Vivo Imaging of the Aneurysm Wall With MRI and a Macrophage-Specific Contrast Agent

OBJECTIVEnBecause of their capability of secreting proteinases, macrophages play a central role in the growth and rupture of aneurysms. Noninvasive imaging of macrophages therefore may yield valuable information about the pathogenesis of aneurysm disease. We studied uptake of the macrophage-specific contrast agent ultrasmall paramagnetic iron oxide (USPIO) in the walls of aneurysms and normal-sized aortas.nnnMATERIALS AND METHODSnSix patients with an aortic and five patients with an iliac aneurysm and 11 age-matched controls were identified in a database of 239 patients who underwent evaluations for the staging of prostate cancer. USPIO-enhanced MRI and contrast-enhanced MDCT were performed for all patients. The presence of USPIO was assessed with an iron-sensitive MRI sequence. Quantification consisted of counting the number of quadrants with USPIO-induced subendothelial signal voids. A chi-square test was used to analyze the significance of the difference between the number of USPIO-positive quadrants in the aneurysm group and that in the control group.nnnRESULTSnThe number of USPIO-positive quadrants was significantly higher in the aneurysm than in the control group: 158 quadrants (4.2%) in the aneurysm group and 13 quadrants (0.4%) in the control group (p < 0.001). Two abdominal aortic aneurysms accounted for 90% (154/171) of all USPIO-positive quadrants.nnnCONCLUSIONnUSPIO uptake is limited or absent in the wall of normal-sized aortas and most aneurysms. However, individual abdominal aortic aneurysms exhibit high levels of USPIO uptake, indicative of extensive macrophage infiltration in the aneurysm wall. Future research should focus on the predictive value of USPIO uptake for growth and rupture of aneurysms.

Genomic DNA Pooling Strategy for Next-Generation Sequencing-Based Rare Variant Discovery in Abdominal Aortic Aneurysm Regions of Interest—Challenges and Limitations

The costs and efforts for sample preparation of hundreds of individuals, their genomic enrichment for regions of interest, and sufficient deep sequencing bring a significant burden to next-generation sequencing-based experiments. We investigated whether pooling of samples at the level of genomic DNA would be a more versatile strategy for lowering the costs and efforts for common disease-associated rare variant detection in candidate genes or associated loci in a substantial patient cohort. We performed a pilot experiment using five pools of 20 abdominal aortic aneurysm (AAA) patients that were enriched on separate microarrays for the reported 9p21.3 associated locus and 42 additional AAA candidate genes, and sequenced on the SOLiD platform. Here, we discuss challenges and limitations connected to this approach and show that the high number of novel variants detected per pool and allele frequency deviations to the usually highly false positive cut-off region for variant detection in non-pooled samples can be limiting factors for successful variant prioritization and confirmation. We conclude that barcode indexing of individual samples before pooling followed by a multiplexed enrichment strategy should be preferred for detection of rare genetic variants in larger sample sets rather than a genomic DNA pooling strategy.