Nuno Dias

The chimney graft: a technique for preserving or rescuing aortic branch vessels in stent-graft sealing zones.

Purpose: To report an alternative to the fenestrated stent-graft for preserving blood flow to side branches in the sealing zones of aortic stent-grafts. Technique: A covered stent is deployed parallel to the main aortic stent-graft, protruding somewhat proximally, like a chimney, to preserve flow to a vital side branch covered by the aortic stent-graft. Use of a chimney graft makes it possible to use standard off-the-shelf stent-grafts to instantly treat lesions with inadequate fixation zones, providing an alternative to fenestrated stent-grafts in urgent cases, in aneurysms with challenging neck morphology, and for reconstituting an aortic side branch unintentionally compromised during endovascular repair. This technique has been used successfully in 10 patients, combining chimney grafts in the renal, superior mesenteric, left subclavian, left common carotid, and innominate arteries with stent-grafts in the abdominal (n=6) or thoracic (n=4) aorta. There has been no late chimney graft—related endoleak on imaging studies up to 8 months. Conclusion: The use of chimney grafts is feasible in the renal and superior mesenteric arteries, as well as in the supra-aortic branches, to facilitate stent-graft repair of thoracic or abdominal aortic lesions with inadequate fixation zones.

Endovascular repair of ruptured abdominal aortic aneurysms: logistics and short-term results.

PURPOSE To report our experience in establishing a treatment protocol for endovascular aneurysm repair (EVAR) of ruptured abdominal aortic aneurysms (rAAA), including an investigation of the reasons for patient exclusion and a report of our short-term results. METHODS Between 1997 and July 2002, 21 patients with rAAA underwent endovascular repair according to our protocol and were followed prospectively. A retrospective analysis was also conducted of 23 rAAA patients treated with open repair from January 2001 through June 2002. Procedural and clinical data from this sample were compared to 14 contemporaneous emergent EVAR cases and analyzed to determine why the open repair patients were not treated with an endovascular approach. RESULTS Among the 21 patients treated with emergent EVAR since the beginning of this protocol, 6 (29%) procedures were performed under local anesthesia and 6 were performed percutaneously. Thirty-day mortality was 19%. In the comparison of 14 emergent EVAR cases to 23 open rAAA repairs, the mean duration of symptoms prior to intervention was 12 hours for the EVAR patients and <1 hour for OR patients. No significant difference was found in operating time, but the EVAR group had significantly less blood loss (p=0.0001) and transfusion needs (p=0.02); duration of intensive care unit stay was significantly shorter in the EVAR group (p=0.02). Thirty-day mortality was 29% (4/14) for EVAR and 35% for OR (8/23) (p>0.05). Reasons for not performing EVAR were unavailability of adequate equipment (n=11) or trained staff (n=7), hemodynamically unstable patient (n=2), mycotic aneurysm (n=2), and unfavorable anatomy in a 60-year old patient with a <5-mm-long, sharply angled infrarenal neck. CONCLUSIONS Endovascular repair of ruptured aortic aneurysms is feasible, and short-term results are promising. Good logistics, adequate training of physicians and staff in an elective setting, and versatile endografts are prerequisites for this type of treatment program.

Feasibility of a branched stent-graft in common iliac artery aneurysms.

Purpose: To evaluate the short-term feasibility, efficacy, and safety of a modular bifurcated stent-graft with an internal iliac artery (IIA) side branch for endovascular repair of aortoiliac aneurysms. Methods: Between 2002 and 2005, 10 male patients (median age 75 years, range 59–83) were treated with a bifurcated stent-graft that included a unilateral side branch for the IIA. The median diameters of the abdominal aortic and common iliac artery (CIA) aneurysms were 56 mm (range 33–80) and 40 mm (range 27–60), respectively. Four patients were treated mainly for the CIA aneurysm. Postoperative endoleaks, patency rate, and vessel morphology were determined with contrast-enhanced computed tomography (CT). Results: All endografts were implanted in the desired position. One IIA occluded intraoperatively, and 1 external iliac artery occlusion was noted 6 months postoperatively; both occlusions were asymptomatic and remain untreated. Three graft-related endoleaks were treated with implantation of adjunctive stent-grafts (2 intraoperative and 1 late). Median follow-up by CT was 2 months (1 week to 32 months). One patient died of myocardial infarction 13 days postoperatively; the stent-graft was patent at autopsy. Conclusion: Stent-grafts with an IIA side branch offer an opportunity to repair aortoiliac aneurysms without sacrificing the IIA. Implantation of the IIA branch is more complex than routine endovascular aneurysm repair and may have contributed to a periprocedural cardiac death. More patients and longer follow-up are needed to verify these data.

Fenestrated endovascular repair for juxtarenal aortic pathology.

OBJECTIVE To evaluate the outcomes after fenestrated endovascular aortic repair (f-EVAR) in a tertiary European referral center. METHODS All patients treated with commercially available custom-made f-EVAR between September 2002 and June 2007 were prospectively enrolled in a computerized database including co-morbidities and aneurysm morphology. Patients were retrospectively analyzed. Follow-up consisted of clinical examinations and computed tomography (CT) scanning. RESULTS A total of 54 patients were included in this study. Median age was 72 (interquartile range [IQR] 68-76) years and 85% were men. Median preoperative aneurysm diameter was 60 (53-66) mm. One hundred thirty-four vessels were targeted (43 scallops, 91 fenestrations) and 96 stents were placed (69 bare, 27 covered). Target vessel catheterization was achieved in 98% of cases. Two patients (3.7%) died within 30 days, 1 from trash embolization and multiorgan failure and 1 from retroperitoneal bleeding caused by a renal artery perforation. Three type I endoleaks occurred intraoperatively, two sealed pre-discharge and one was treated with a Palmaz stent (Cordis, Miami Lakes, Fla) on postoperative day 4. Thirteen patients had type II endoleaks, and 2 required treatment. The median clinical follow-up was 25 (12-32) months with median CT follow-up of 22 (4-26) months. Aneurysm diameter decreased >or=5 mm in 47%, was unchanged in 50%, and increased >or=5 mm in 3% of patients at 1 year. There were three type II endoleaks at 1-year follow-up, one of which was successfully treated after 19 months due to aneurysm growth. Ninety-six percent of target vessels remained patent during the study period and all occlusions occurred within the first year of follow-up. Five target vessels occluded (2 renal arteries [RAs] and 3 superior mesenteric arteries [SMAs]) without symptoms during follow-up and successful reinterventions were done on 2 stenosed RAs. Three patients suffered creatinine increase but none needed dialysis. One late aneurysm-related death occurred due to massive bleeding during redo surgery for infection. CONCLUSION Despite complex anatomy or severe comorbidities in these patients f-EVAR has acceptable short- and midterm results in this series which includes a learning curve and offers a valid treatment alternative to patients unsuitable for standard EVAR or open repair.

Is There a Benefit of Frequent CT Follow-up After EVAR?

OBJECTIVE Imaging follow-up (FU) after endovascular aneurysm repair (EVAR) is usually performed by periodic contrast-enhanced computed tomography (CT) scans. This study aims to evaluate the effectiveness of CT-FU after EVAR. METHODS In this study, 279 of 304 consecutive patients (261 male, aged 74 years (interquartile range (IQR): 70-79 years) with a median abdominal aortic aneurysm (AAA) diameter of 58 mm (IQR: 53-67 mm)) underwent at least one of the yearly CT scans and plain abdominal films after EVAR. All patients received Zenith stent-grafts for non-ruptured AAAs at a single institution. Patients were considered asymptomatic when a re-intervention was done solely due to an imaging FU finding. The data were prospectively entered in a computer database and retrospectively analysed. RESULTS As a follow-up, 1167 CT scans were performed at a median of 54 months (IQR: 34-74 months) after EVAR. Twenty-seven patients exhibited postoperative AAA expansion (a 5-year expansion-free rate of 88+/-2%), and 57 patients underwent 78 postoperative re-interventions with a 5-year secondary success rate of 91+/-2%. Of the 279 patients, 26 (9.3%) undergoing imaging FU benefitted from the yearly CT scans, since they had re-interventions based on asymptomatic imaging findings: AAA diameter expansion with or without endoleaks (n=18), kink in the stent-graft limbs (n=4), endoleak type III due to stent-graft limb separation without simultaneous AAA expansion (n=2), isolated common iliac artery expansion (n=1) and superior mesenteric artery malperfusion due to partial coverage by the stent-graft fabric (n=1). CONCLUSIONS Less than 10% of the patients benefit from the yearly CT-FU after EVAR. Only one re-intervention due to partial coverage of a branch by the stent-graft would have been delayed if routine FU had been based on simple diameter measurements and plain abdominal radiograph. This suggests that less-frequent CT is sufficient in the majority of patients, which may simplify the FU protocol, reduce radiation exposure and the total costs of EVAR. Contrast-enhanced CT scans continue, nevertheless, to be critical when re-interventions are planned.

Intraoperative proximal endoleaks during AAA stent-graft repair: evaluation of risk factors and treatment with Palmaz stents

PURPOSE To study factors that might contribute to intraoperative proximal type I endoleak and to evaluate the placement of giant Palmaz stents as a therapeutic option. METHODS Thirty-three patients (30 men; median age 72 years, range 50-85) with abdominal aortic aneurysms underwent implantation of fully supported Gianturco Z-stent-based endografts (12 custom-made aortomonoiliac and 21 bifurcated Zenith devices). Ten (30%) patients were treated for intraoperative proximal endoleaks. Stent-graft oversizing and neck angulation, length, and shape were compared between patients with and without leaks. RESULTS In 9 cases, the endoleaks were successfully treated with intraoperative placement of Palmaz stents without complications. In 1 patient, a leak that was resolved intraoperatively with balloon dilation reappeared 1 month later; a Palmaz stent was deployed successfully. Stent-graft oversizing did not differ significantly between patients who developed proximal endoleaks and those who did not (median 4.0 mm in both groups, p = 0.47). Median neck length was 21.0 mm in patients with endoleak and 28.0 mm in those without (p > 0.99). Median neck angulation was 30 degrees in both groups (p = 0.33), and the presence of a conical aneurysm neck was not significantly different (2/10 versus 6/23, p > 0.99). All aneurysms remained excluded at a median follow-up of 13 months (range 6-24). CONCLUSIONS Stent-graft oversizing and neck morphology (length, angulation, and conical shape) do not seem to correlate with the incidence of proximal type I endoleaks. Palmaz stent placement appears to be a feasible and safe treatment option for this complication.

Outcomes of fenestrated endovascular repair of juxtarenal aortic aneurysm

OBJECTIVE To evaluate late outcomes after fenestrated endovascular aortic repair (f-EVAR) in a tertiary European referral center. METHODS In 2009, we published short- and midterm results after f-EVAR in the first 54 patients treated with this technique at our center between September 2002 and June 2007. In this paper, we provide long-term follow-up of the same patient cohort with the main focus on target vessel (TV) patency, renal function, reinterventions, and survival. RESULTS A total of 54 patients were included in this study. Median age was 72 years (interquartile range [IQR], 68-76 years) at primary operation, and 85% were men. Median preoperative aneurysm diameter was 60 mm (IQR, 53-66 mm). One hundred thirty-four vessels were targeted (mean, 2.5 per patient), and 96 TV stents were placed. The median clinical follow-up was 67 months (IQR, 37-90 months), and computed tomography follow-up was 60 months (IQR, 35-72 months). Aneurysm diameter decreased ≥ 5 mm in 39% ± 7% at 12 months, 64% ± 8% at 36 months, and 71% ± 8% at 60 months. Primary TV patency was 94% ± 2% at 12 months, 91% ± 3% at 36 months, and 90% ± 3% at 60 months. Glomerular filtration rate decreased by 17% at 59 months (IQR, 26-73 months) follow-up (60 [IQR, 46-79] vs 50 [IQR, 38-72] mL/min/1.73 m(2); P < .001), and one patient became dialysis-dependent secondary to a renal stent occlusion. Reintervention-free survival was 88% ± 5% at 12 months, 69% ± 7% at 36 months, and 56% ± 5% at 60 months. At least one reintervention was done in 37% of patients, of which 29% were endoleak-related, 26% TV-related, 13% graft-limb-related, and 32% due to other causes. The majority of reinterventions (68%) were based on complications detected on routine follow-up. Estimated overall survival was 93% ± 4% at 12 months, 76% ± 6% at 36 months, and 60% ± 7% at 60 months. In total, 54% of the patients died during the 10-year study period, where 9% died of aneurysm-related causes. CONCLUSIONS Long-term mortality after f-EVAR is high, but most patients die from nonaneurysmal causes. Aneurysm-related mortality is associated with technical complications that can be reduced with increased experience. Reinterventions are common, and most complications are detected on routine follow-up.

EVAR of Aortoiliac Aneurysms with Branched Stent-grafts.

INTRODUCTION Branched iliac stent-grafts (bSG) have recently been developed in order to preserve internal iliac artery (IIA) flow in patients with aneurysmal or short common iliac arteries. The aim of this study is to evaluate a single-center experience with bSG for the IIA. METHODS Twenty-two male patients (70 (IQR 65-79) years old) underwent EVAR with 23 bSG (1 bilateral repair) between September 2002 and August 2007. Median AAA diameter was 52 (37-60) mm while common iliac diameter on the side of the bSG was 34 (27-41) mm. Two in-house modified Zenith SG and subsequently 21 commercially available bSG (18 Zenith Iliac Side and 3 Helical Branches) were used. Follow-up (FU) included CT at one month and yearly thereafter. Data was prospectively entered in a database. RESULTS Primary technical success was 91% (21 bSG). Median FU duration was 20 (8-31) months. One patient (5 %) died after discharge from acute myocardial infarction on day 13. Another patient died 30 months after EVAR of an unrelated cause. The overall bSG patency was 74% due to 6 branch occlusions (2 intraoperative and 4 late). All patients with patent bSG were asymptomatic. Three occlusions were asymptomatic findings on CT, while the other three developed claudication (two patients with contralateral IIA occlusion and one with simultaneous occlusion of the external iliac). One patient (5%) developed an asymptomatic type III endoleak at 1 month and was successfully treated with a bridging SG. Overall, four patients (18%) required reinterventions (1 bilateral stenting of the external iliac arteries, 1 external and 1 internal SG extensions and 1 femoro-femoral cross-over bypass). Nine out of 16 patients (56%) with CT-FU>/=1 year had shrinking aneurysms. There were no postoperative aneurysm expansions. CONCLUSIONS EVAR of aortoiliac aneurysms with IIA bSG is a good alternative to occlusion of the IIA in patients with challenging distal anatomy.

Changes Related to Age and Cerebrovascular Symptoms in the Extracellular Matrix of Human Carotid Plaques

Background and Purpose— Many processes involved in the pathogenesis of atherosclerosis result in modifications of the extracellular matrix. These changes not only determine the mechanical stability of atherosclerotic lesions but can directly or indirectly influence further development of the lesions. The purpose of the present study was to compare the matrix composition of human carotid plaques from symptomatic patients with those obtained from patients without symptoms. Furthermore, matrix changes related to age were studied. Methods— Thirty atherosclerotic carotid plaques were removed by endarterectomy from 27 patients and divided into 2 groups on the basis of the presence of ipsilateral symptoms. The plaques were homogenized, and the total levels of the major components of the extracellular matrix were determined. Results— Plaques associated with symptoms were characterized by increased levels of elastin (1.58±0.46 versus 1.24±0.40 mg/g wet wt;P =0.03) and decreased levels of hydroxyapatite (45.1±46.3 versus 131.4±111.7 mg/g wet wt;P =0.02) compared with asymptomatic plaques. The increase in elastin in plaques from symptomatic patients was due to elevated levels of an intermediate-size fraction, as determined by liquid chromatography. Collagen and sulfated glycosaminoglycans were present in equal amounts in both groups. Elastin content in carotid plaques decreased with age. Conclusions— Carotid plaques from symptomatic patients have lower levels of hydroxyapatite than those from asymptomatic patients. The present study also raises the possibility that non–cross-linked forms of elastin, increased in plaques associated with symptoms, could be a marker of plaque vulnerability and/or directly induce harmful cellular activities or increase lipoprotein retention in the vascular wall.

Elastin and Calcium Rather Than Collagen or Lipid Content Are Associated With Echogenicity of Human Carotid Plaques

Background and Purpose— Echolucent carotid plaques have been associated with increased risk for stroke. Histological studies suggested that echolucent plaques are hemorrhage- and lipid-rich, whereas echogenic plaques are characterized by fibrosis and calcification. This is the first study to relate echogenicity to plaque composition analyzed biochemically. Methods— Echogenicity of human carotid plaques was analyzed by standardized high-definition ultrasound and classified into echolucent, with gray-scale median (GSM) <32 and echogenic with GSM ≥32. The biochemical composition of the plaques was assessed by fast-performance liquid chromotography and high-performance thin-layer chromotography. Results— As assessed biochemically (milligrams per gram [mg/g]), echolucent plaques contained less hydroxyapatite (43.8 [SD 41.2] mg/g versus 121.6 [SD 106.2] mg/g; P=0.018), more total elastin (1.7 [SD 0.4] mg/g versus 1.2 [SD 0.4] mg/g; P=0.008), and more intermediate-size elastin forms (1.2 [SD 0.3] mg/g versus 0.8 [SD 0.4] mg/g; P=0.018). There was no difference in collagen amount between echogenic and echolucent plaques, neither biochemically (15.3 [SD 3.7] mg/g versus 14.4 [SD 3.4] mg/g) nor histologically (13.4 [SD 4.9] % versus 13.0 [SD 5.6] %). Cholesterol esters, unesterified cholesterol, and triglycerides were increased in plaques associated with symptoms (22.5 [SD 23.3] mg/g versus 13.3 [SD 3.2]; P=0.04), but no differences were detected between echolucent and echogenic plaques (13.5 [SD 4.0] versus 20.2 [SD 21.5] mg/g). Similar results were obtained by Oil Red O staining (symptomatic 7.6 [SD 4.7] % versus asymptomatic 4.2 [SD 3.6] %; P=0.03; echolucent 5.9 [SD 4.1] % versus echogenic 5.0 [SD 4.0] % of area). Conclusions— Echogenicity of carotid plaques is mainly determined by their elastin and calcium but not collagen or lipid content. In addition, echolucency is associated to higher elastin content.