Konstantinos P. Donas

Use of covered chimney stents for pararenal aortic pathologies is safe and feasible with excellent patency and low incidence of endoleaks.

BACKGROUND To present the clinical experience of consecutive series with use of balloon-expandable and self-expanding chimney endografts (balloon-expandable covered stent group [BECS] vs self-expanding covered stent group [SECS]) in the endovascular treatment of challenging aortic pathologies requiring renal and/or visceral revascularization. METHODS Between January 2009 and May 2011, data for 37 high-risk patients from one center and 35 patients from another institution, with pararenal aortic pathologies treated by the chimney endovascular technique, were prospectively collected. The chimney-graft technique is based on the deployment of a covered or bare-metal stent parallel to the aortic endograft, thereby creating a conduit that runs outside the aortic main endograft, and has been proposed to ensure secure proximal fixation extending the sealing zones. RESULTS Forty-six consecutive target vessels (43 renal arteries and 3 superior mesenteric arteries) were revascularized by the Advanta (Atrium, Hudson, NH) BECS (1.2 chimneys/patient); in contrast, 81 consecutive target vessels (64 renal arteries, 11 superior mesenteric arteries, and 6 celiac trunks) were revascularized by the Viabahn (Gore, Flagstaff, Ariz) SECS (2.3 chimneys/patient). The success rate for target vessel preservation was 97.8% for the BECS group and 100% for the SECS group in the entire follow up. There was one symptomatic left renal artery occlusion of the BECS group treated by open thrombectomy of the left renal artery and placement of 8-mm Dacron (BBraun, Aesculap AG, Tuttlingen, Germany) iliorenal bypass. Additionally, one patient underwent repeat balloon angioplasty with a 5-mm balloon due to high-grade in-stent stenosis of a 6 × 59 Advanta stent graft 12 months postoperatively. Overall, one perioperative (and not present in the computed tomography angiography at discharge) type Ia endoleak was detected in the BECS group. In contrast, five perioperative type Ia endoleaks were present in the SECS group; however, only one of them was persistent in the radiological imaging and was treated by proximal extension of a 5-mm cuff, 1 year postoperatively, due to continuous aneurismal sac increase. No patient of any subgroup developed postoperative persistent renal insufficiency with need of hemodialysis. Thirty-day and during the follow-up procedure-related mortality was 0% for both BECS and SECS groups. CONCLUSIONS In summary, midterm results of use of covered chimney stents for pararenal aortic pathologies show safety and feasibility with excellent patency and low incidence of endoleaks.

Use of Abdominal Chimney Grafts is Feasible and Safe: Short-term Results

Purpose: To present our initial experience with the use of chimney grafts in endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms (AAAs) with challenging anatomy. Methods: Among 390 EVAR cases performed at our institution between November 2008 and February 2010, 15 patients (all men; mean age 81.8 years) underwent EVAR with synchronous placement of chimney grafts. The chimney technique involved placing covered stents parallel to the main aortic stent-graft to preserve or rescue flow to aortic branch vessels while extending the proximal fixation zone. All patients presented with pararenal aortic aneurysms with short necks (between 0 and 10 mm long) that required either suprarenal clamping to tailor a proximal anastomosis in open repair or suprarenal fixation to anchor an endoprosthesis. Chimney grafts were implanted into 10 left renal and 5 right renal arteries. Results: The immediate technical success was 100%. One early type II endoleak due to retrograde flow from the inferior mesenteric artery was detected and is under surveillance. Mean follow-up was 6.8 months (range 1–13). One chimney graft occluded 45 days postoperatively; the patient underwent open thrombectomy of the left renal artery and iliorenal bypass. The creatinine value at discharge was 1.6 mg/dL, and resting renal scintigraphy showed 36% perfusion for the left kidney and 64% for the right kidney. During follow-up, no patient required hemodialysis; no aneurysm-related deaths were noted. Conclusion: This limited experience demonstrates that the use of abdominal chimney grafts is feasible and safe. Long-term results in larger patient cohorts are needed evaluate the utility of this alternative endovascular technique.

Collected world experience about the performance of the snorkel/chimney endovascular technique in the treatment of complex aortic pathologies: the PERICLES registry.

OBJECTIVES We sought to analyze the collected worldwide experience with use of snorkel/chimney endovascular aneurysm repair (EVAR) for complex abdominal aneurysm treatment. BACKGROUND EVAR has largely replaced open surgery worldwide for anatomically suitable aortic aneurysms. Lack of availability of fenestrated and branched devices has encouraged an alternative strategy utilizing parallel or snorkel/chimney grafts (ch-EVAR). METHODS Clinical and radiographic information was retrospectively reviewed and analyzed on 517 patients treated by ch-EVAR from 2008 from 2014 by prearranged defined and documented protocols. RESULTS A total of 119 patients in US centers and 398 in European centers were treated during the study period. US centers preferentially used Zenith stent-grafts (54.2%) and European centers Endurant stent-grafts (62.2%) for the main body component. Overall 898 chimney grafts (49.2% balloon expandable, 39.6% self-expanding covered stents, and 11.2% balloon expandable bare metal stents) were placed in 692 renal arteries, 156 superior mesenteric arteries (SMA), and 50 celiac arteries. At a mean follow-up of 17.1 months (range: 1-70 months), primary patency was 94%, with secondary patency of 95.3%. Overall survival of patients in this high-risk cohort for open repair at latest follow-up was 79%. CONCLUSIONS This global experience represents the largest series in the ch-EVAR literature and demonstrates comparable outcomes to those in published reports of branched/fenestrated devices, suggesting the appropriateness of broader applicability and the need for continued careful surveillance. These results support ch-EVAR as a valid off-the-shelf and immediately available alternative in the treatment of complex abdominal EVAR and provide impetus for the standardization of these techniques in the future.

Evaluation of the Endurant stent graft under instructions for use vs off-label conditions for endovascular aortic aneurysm repair

BACKGROUND This study evaluated the early and intermediate results of endovascular aortic aneurysm repair (EVAR) using the Endurant stent graft (Medtronic Cardiovascular, Santa Rosa, Calif) in patients treated according to device-specific instructions for use (IFU) for the proximal aortic neck compared with those obtained in patients treated in an off-label (OL) situation. METHODS Between November 2007 and March 2010, 177 consecutive patients with abdominal aortic aneurysms (AAAs) were treated with the Endurant stent graft at our centers. The IFU for the Endurant stent graft included a proximal neck of 15 mm in length and <75° of angulation or 10 mm of neck length and <60° of angulation. The 121 patients (68.4%) operated on according to IFU were compared with 56 (31.6%) who underwent EVAR in OL circumstances to evaluate significant differences in demographics, intraoperative technical factors, and early (30 days) and intermediate outcomes (1 year). RESULTS Significantly more patients were aged >80 years in the OL group (37.5% vs 19%, P = .008), and they also had larger aneurysms (59 ± 10.6 vs 55.9 ± 10.8 mm, P = .05) and required a longer procedure time (69.3 ± 27.2 vs 60.8 ± 20.4 minutes, P = .02). At 30 days, the risk of type I endoleak was higher in the OL group (2 patients, 3.6% vs 0 in IFU), but this did not reach statistical significance (P = .09). The two groups were similar in rates of perioperative mortality, major morbidity, technical success, clinical success, complications, and reinterventions. At 1 year, there were no differences between the two groups in survival, freedom from any device-related reinterventions, and freedom from graft thrombosis. Estimated 1-year freedom from type I endoleak was 100% in the IFU group vs 93.3% in the OL group (P = .01). CONCLUSIONS In patients with both normal and complex anatomy of the proximal aortic neck, the Endurant stent graft obtained acceptable results, with no difference in survival, morbidity, or reinterventions. However, there was a greater risk of type I endoleak when OL indications were applied. Longer term follow-up is required to evaluate the effectiveness of this endograft in preventing late aneurysm-related complications.

Early and midterm outcome of a novel technique to simplify the hybrid procedures in the treatment of thoracoabdominal and pararenal aortic aneurysms

BACKGROUND To evaluate the effectiveness of the Viabahn Open Revascularization Technique (VORTEC) in the treatment of thoracoabdominal aortic aneurysms (TAAAs) and pararenal aortic aneurysms (PAAAs) by hybrid procedures. METHODS Between December 2004 and March 2009, 58 patients (45 male, mean age, 74 years) were diagnosed with TAAA (n = 30) and PAAA (n = 28) and treated electively by combined hybrid techniques. Hybrid procedure includes bypass surgery of the visceral and renal arteries (debranching or rerouting), followed by endovascular exclusion of the aortic aneurysm. One hundred thirteen renovisceral vessels were revascularized in a retrograde fashion (ie, 98 renal and 15 visceral arteries), using VORTEC. The novel technique consists of the placement of self-expanding stent-grafts (Viabahn graft, Gore and Associates, Flagstaff, Ariz) in Seldinger technique into the renal and visceral arteries after surgical identification of the origin of the arteries. The end of the stent outside of the renal artery was sutured end to side directly with the main feeding graft, bypassing the aneurysm, or was fixed into an interposition branch graft on the main bypass. All cases were treated by two-staged approach (endovascular aneurysm repair [EVAR] performed after recovery from the debranching procedure). Computed tomography angiography and clinical follow-up were obtained before discharge, at six weeks, and three, six, and 12 months after the procedure and then annually. RESULTS Primary technical success of VORTEC was achieved in all patients. Overall primary patency rate of the novel technique was 97% during a mean follow-up of 22.1 +/- 12.9 months (range, 1-52 months); the primary patency of the subgroups PAAAs and TAAAs was 97.7% and 96.4%, respectively; the assisted primary patency rate was 98%, as two occluded Viabahn grafts were reopened by thrombolysis and thrombus aspiration. No patient required long-term hemodialysis. Thirty-day mortality rate was 8.6% (5/58) and 25.8% (15/58) for the entire follow up. Permanent neurologic deficit occurred in two cases (3.4%; paraplegia, n = 1; paraparesis, n = 1). The overall endoleak rate was 17.1% as three patients presented early (30-day) type I endoleak, treated by cuff-implantation, and six patients presented type II endoleak, three of them treated by coil embolization of the patent vessel and the others treated conservatively with radiological surveillance. CONCLUSION VORTEC allows performance of easy, safe, and minimally invasive revascularization of renal and visceral arteries and may represent a significant technical advance in the hybrid repair of TAAAs and PAAAs. However, the questions of reproducibility by other centers and long-term results are mandatory to establish this alternative revascularization option.

Early Outcomes for Fenestrated and Chimney Endografts in the Treatment of Pararenal Aortic Pathologies Are Not Significantly Different: A Systematic Review With Pooled Data Analysis

Purpose To compare short-term outcomes between fenestrated and chimney endografts for pararenal aortic pathologies. Methods An English-language literature search up to January 2012 found 129 articles evaluating the immediate outcomes of endovascular repair of degenerative juxta-/suprarenal aortic aneurysms, type I endoleaks, and para-anastomotic aneurysms using the chimney technique or fenestrated endografts. Data concerning thoracoabdominal aortic aneurysms, ruptured aneurysms, and reports with <5 cases were excluded (n=84). An additional 28 articles were excluded for insufficient data, leaving 17 articles for review: 5 dealing with chimney grafts in 123 patients with pararenal aortic pathologies and 12 presenting data on 631 patients undergoing fenestrated stent-grafting. The composite endpoints were 30-day mortality, deterioration of renal function, new postoperative dialysis dependence, and endoleak rate. Results Cumulative 30-day procedure-related mortality was 0.58% (95% CI 0.0% to 2.93%) for the chimney group (n=3) and 1.17% (95% CI 0.26% to 2.09%, p=0.645) for the f-EVAR group (n=9). In the f-EVAR group, 86 (9.67%;95% CI 4.77% to 14.57%) patients suffered from postoperative renal impairment vs. 16 (12.43%) patients in the chimney group (95% CI 2.39% to 22.48%, p=0.628). In the chimney group, 4 (0.57%;95% CI 0.0% to 2.94%) patients required persistent postoperative dialysis in contrast to the 1.33% (95% CI 0.29% to 2.37%, p=0.567) rate (n=9) in patients undergoing f-EVAR. There were also no significant differences recorded in the endoleak rate: 1.93% (95% CI 0.0% to 4.82%) of the chimney patients had a persistent type Ia endoleak vs. 2.06% (95% CI 0.69% to 3.43%) for the f-EVAR group (p=0.939). For type II endoleaks, the rates were 2.16% (95% CI 0.0% to 10.77%) for the chimney group vs. 6.88% (95% CI 1.92% to 11.83%) for the f-EVAR group (p=0.352). No patient in the chimney group had a type III endoleak, and the rate was low in the f-EVAR group (0.32%,95% CI 0.0% to 0.91%, p=0.079). Conclusion No statistically significant differences were found between the two endovascular approaches for pararenal aortic pathologies in terms of 30-day mortality, renal impairment, or endoleak. These findings support the assumption that chimney grafts may be a reliable alternative in the treatment of pararenal aortic pathologies.

Secondary Procedures After Aortic Aneurysm Repair With Fenestrated and Branched Endografts

Purpose To investigate the secondary procedures in patients with previous endovascular aortic repair by fenestrated or branched stent-grafts for aneurysms involving the renal and visceral vessels. Methods Between January 2001 and May 2010, 107 consecutive high-risk patients (97 men; mean age 73 years, range 50–86) with aortic aneurysms involving the renal and visceral arteries were treated with endovascular techniques. A custom-made Zenith graft was used in all patients. All secondary graft-related procedures performed in the perioperative period and during follow-up were analyzed. Estimates of survival, freedom from migration/type I endoleak, and freedom from any device-related secondary procedures were assessed with Kaplan-Meier analyses. Results The 30-day mortality rate was 1.9%. During follow-up (mean 25 months, range 1–94), 34 secondary procedures were performed in 28 (26.2%) patients for 6 (17.6%) limb graft stenoses/thromboses (5.6% of 107 cases), 8 (23.5%) in-stent visceral vessel stenoses/ occlusions (7.5% of 107 cases), 8 (23.5%) migrations/type I endoleaks with/without visceral stent fractures (7.5% of 107 cases), and 12 (35.3%) type III endoleaks (9.3% of 107 cases). The mean interval between the primary and secondary procedures was 12.9 months (range 1?68). In 26 (76.5%) of 34 cases, a secondary endovascular procedure was performed; in the remaining 8 (23.5%) cases, the complication was treated surgically. The secondary procedure was unsuccessful in 9 cases of visceral vessel compromise (failure to cannulation, stent fracture/migration, in-stent stenosis/occlusion). Estimated 3-year survival was 77%, while the 3-year rate for freedom from any device-related secondary procedure was 75.5%. Conclusion The incidence of early and late complications requiring a secondary procedure after treatment with fenestrated or branched devices was not negligible. Endoleak type III represented the most common cause for reintervention during follow-up. Secondary procedures performed for visceral vessel compromise had high rates of treatment failure. Accurate preoperative planning, the advent of new materials/techniques, and strict follow-up could be the key factors to improving the results of fenestrated or branched stent-graft interventions and to reduce the rate of secondary procedures.

CT angiography at 24 months demonstrates durability of EVAR with the use of chimney grafts for pararenal aortic pathologies.

Purpose To present the 24-month radiological follow-up data for patients with pararenal aortic pathologies treated with chimney and periscope grafts during endovascular repair. Methods Between January 2008 and December 2011, 124 high-risk patients with complex pararenal aortic pathologies were treated using the chimney technique at 2 European vascular and cardiovascular centers with advanced experience of the described technique. In particular, 50 patients were treated at Site 1 and 74 at Site 2. Forty (32.2%) patients (32 men; mean age 79.2±4.9 years) completed computed tomographic angiography follow-up at 24 months postoperatively. Results The overall technical success was 100%, and the early- and midterm procedure-related mortality was 0%. Three (2.4%) patients had a perioperative type Ia endoleak that persisted; two were treated by transbrachial perigraft embolization and cuff implantation. The last patient is under radiological surveillance due to a “low-flow” type Ia endoleak and stable sac size. A type II endoleak was detected in 7 (5.6%) patients. During the 2-year follow-up, significant shrinkage (>5 mm; n=22) or stable aneurysm diameter (n=14) was seen in 36 (90%) of the cases. Overall, mean aneurysm sac shrinkage was 12% (p=0.002) and 10% (p=0.014) for the 2 centers, respectively (overall p=0.008). The causes for sac progression in the 4 (10%) patients were a type Ia endoleak, 2 type II endoleaks, and endotension. Conclusion The present study demonstrates that the use of chimney and/or periscope endografts for pararenal aortic pathologies achieves and maintains successful exclusion of the aneurysm in 90% of the cases at 24 months of radiological follow-up. In centers experienced with this approach, the chimney technique may represent a reliable therapeutic modality in selected patients.

Use of chimney grafts in aortic arch pathologies involving the supra-aortic branches.

Purpose To present a clinical experience with the use of chimney grafts in the endovascular repair of aortic arch pathologies involving the supra-aortic branches. Methods The chimney technique consists of endovascular stent or stent-graft placement parallel to the main aortic stent-graft in order to preserve or rescue flow to aortic branch vessels and to allow proximal extension of endograft fixation zones. Between April 2009 and January 2011, 9 patients (7 men; mean age 58 years, range 39–76) had chimney grafts installed to the left subclavian artery (LSA) or left common carotid artery (LCCA) during urgent thoracic endovascular aortic repair (TEVAR) of 5 aortic arch aneurysms, a mobile aortic thrombus with peripheral embolism, symptomatic type B dissection, penetrating aortic ulcer, and persistent type I endoleak after TEVAR. Eight chimney grafts were implanted into the LSA in 6 patients and 5 into the LCCA in the other 3 patients. Results The immediate technical success was 88.9%. The post-TEVAR type I endoleak persisted despite the chimney graft; the patient underwent surgical arch replacement. One patient died within 30 days due to cardiac insufficiency. There were 2 access site complications requiring surgery (brachial artery pseudoaneurysm and heavily calcified femoral artery puncture site). Over a median follow-up of 15 months (range 4–22), all chimney grafts remained patent in the 7 surviving and successfully treated patients. Conclusion The use of chimney grafts in selected aortic arch pathologies with involvement of supra-aortic branches is safe and feasible. Long-term results and large series are needed in order to draw robust conclusions regarding this promising alternative endovascular technique.

Endurant stent-graft: a 2-year, single-center experience with a new commercially available device for the treatment of abdominal aortic aneurysms.

Purpose: To evaluate early and midterm results of the Endurant stent-graft in the treatment of abdominal aortic aneurysms (AAAs). Methods: From November 2007 to December 2009, 156 patients (142 men; mean age 73.6 years, range 51–90) were treated with the Endurant stent-graft at our center. More than half (106, 67.9%) had hostile proximal neck anatomy. Early (30-day) technical success, clinical success, major morbidity, and mortality rates were analyzed, as well as estimated 2-year survival, freedom from types I/III endoleak, freedom from graft thrombosis, freedom from any device-related reinterventions, and factors affecting 2-year freedom from types I/III endoleak. Results: Immediate intraoperative technical and clinical success was achieved in all cases. In 14 (9%) cases with a proximal neck <5 mm long, a “chimney” technique was used. At discharge, computed tomography demonstrated 2 (1.3%) type I endoleaks. At 30 days, 4 (2.6%) patients had died (2 were urgent cases); the 30-day major morbidity was 7.7%. The overall 30-day technical success and clinical success rates were 98.7% and 95.5%, respectively. During a mean 9-month follow-up (range 1–24), 3 patients died (one of them from AAA rupture). Estimated survival, freedom from types I/III endoleak, freedom from graft thrombosis, and freedom from any device-related reinterventions at 2 years were 94.7%, 96.9%, 97.8%, and 92.6%, respectively. Conclusion: The Endurant stent-graft seems to be safe and effective in endovascular aneurysm repair (EVAR), even in patients with hostile aortoiliac anatomy. However, perioperative and midterm complications occur, which could be explained by the expansion of indications for EVAR. Further studies are needed to evaluate the long-term results.