Christopher J. Kwolek

Pivotal results of the Medtronic Vascular Talent Thoracic Stent Graft System: the VALOR trial.

OBJECTIVE This report summarizes the 30-day and 12-month results of endovascular treatment using the Medtronic Vascular Talent Thoracic Stent Graft System (Medtronic Vascular, Santa Rosa, Calif) for patients with thoracic aortic aneurysms (TAA) who are considered candidates for open surgical repair. METHODS The study was a prospective, nonrandomized, multicenter, pivotal trial conducted at 38 sites. Enrollment occurred between December 2003 and June 2005. Standard follow-up interval examinations were prescribed at 1 month, 6 months, 1 year, and annually thereafter. These endovascular results were compared with retrospective open surgical data from three centers of excellence. RESULTS The Evaluation of the Medtronic Vascular Talent Thoracic Stent Graft System for the Treatment of Thoracic Aortic Aneurysms (VALOR) trial enrolled 195 patients, and 189 were identified as retrospective open surgical subjects. Compared with the open surgery group, the VALOR test group had similar age and sex distributions, but had a smaller TAA size. Patients received a mean number of 2.7 +/- 1.3 stent graft components. The diameters of 25% of the proximal stent graft components implanted were <26 mm or >40 mm. Left subclavian artery revascularization was performed before the initial stent graft procedure in 5.2% of patients. Iliac conduits were used in 21.1% of patients. In 33.5% of patients, the bare spring segment of the most proximally implanted device was in zones 1 or 2 of the aortic arch. In 194 patients (99.5%), vessel access and stent graft deployment were successful at the intended site. The 30-day VALOR results included perioperative mortality, 2.1%; major adverse advents, 41%; incidence of paraplegia, 1.5%; paraparesis, 7.2%; and stroke, 3.6%. The 12-month VALOR results included all-cause mortality, 16.1%; aneurysm-related mortality, 3.1%; conversion to open surgery, 0.5%; target aneurysm rupture, 0.5%; stent graft migration >10 mm, 3.9%; endoleak (12.2%), stent graft patency, 100%; stable or decreasing aneurysm diameter, 91.5%; and loss of stent graft integrity, four patients. No deployment-related events or perforation of the aorta by a graft component occurred. The Talent Thoracic Stent Graft showed statistically superior performance with respect to acute procedural outcomes (P < .001), 30-day major adverse events (41% vs 84.4%, P < .001), perioperative mortality (2% vs 8%, P < .01), and 12-month aneurysm-related mortality (3.1% vs 11.6%, P < .002) vs open surgery. CONCLUSIONS The pivotal VALOR 12-month trial results demonstrate that the Medtronic Talent Thoracic Stent Graft System is a safe and effective endovascular therapy as an alternative to open surgery in patients with TAA who were considered candidates for open surgical repair.

Long-term Outcomes After Endovascular Abdominal Aortic Aneurysm Repair: The First Decade

Objective:The proper role of endovascular abdominal aortic aneurysm repair (EVAR) remains controversial, largely due to uncertain late results. We reviewed a 12-year experience with EVAR to document late outcomes. Methods:During the interval January 7, 1994 through December 31, 2005, 873 patients underwent EVAR utilizing 10 different stent graft devices. Primary outcomes examined included operative mortality, aneurysm rupture, aneurysm-related mortality, open surgical conversion, and late survival rates. The incidence of endoleak, migration, aneurysm enlargement, and graft patency was also determined. Finally, the need for reintervention and success of such secondary procedures were evaluated. Kaplan-Meier and multivariate methodology were used for analysis. Results:Mean patient age was 75.7 years (range, 49–99 years); 81.4% were male. Mean follow-up was 27 months; 39.3% of patients had 2 or more major comorbidities, and 19.5% would be categorized as unfit for open repair. On an intent-to-treat basis, device deployment was successful in 99.3%. Thirty-day mortality was 1.8%. By Kaplan-Meier analysis, freedom from AAA rupture was 97.6% at 5 years and 94% at 9 years. Significant risk factors for late AAA rupture included female gender (odds ratio OR, 6.9; P = 0.004) and device-related endoleak (OR, 16.06; P = 0.009). Aneurysm-related death was avoided in 96.1% of patients, with the need for any reintervention (OR, 5.7 P = 0.006), family history of aneurysmal disease (OR, 9.5; P = 0.075), and renal insufficiency (OR, 7.1; P = 0.003) among its most important predictors. 87 (10%) patients required reintervention, with 92% of such procedures being catheter-based and a success rate of 84%. Significant predictors of reintervention included use of first-generation devices (OR, 1.2; P < 0.01) and late onset endoleak (OR, 64; P < 0.001). Current generation stent grafts correlated with significantly improved outcomes. Cumulative freedom from conversion to open repair was 93.3% at 5 through 9 years, with the need for prior reintervention (OR, 16.7; P = 0.001) its most important predictor. Cumulative survival was 52% at 5 years. Conclusions:EVAR using contemporary devices is a safe, effective, and durable method to prevent AAA rupture and aneurysm-related death. Assuming suitable AAA anatomy, these data justify a broad application of EVAR across a wide spectrum of patients.

Outcomes following endovascular abdominal aortic aneurysm repair (EVAR): an anatomic and device-specific analysis.

OBJECTIVE We performed a device-specific comparison of long-term outcomes following endovascular abdominal aortic aneurysm repair (EVAR) to determine the effect(s) of device type on early and late clinical outcomes. In addition, the impact of performing EVAR both within and outside of specific instructions for use (IFU) for each device was examined. METHODS Between January 8, 1999 and December 31, 2005, 565 patients underwent EVAR utilizing one of three commercially available stent graft devices. Study outcomes included perioperative (< or =30 days) mortality, intraoperative technical complications and need for adjunctive procedures, aneurysm rupture, aneurysm-related mortality, conversion to open repair, reintervention, development and/or resolution of endoleak, device related adverse events (migration, thrombosis, or kinking), and a combined endpoint of any graft-related adverse event (GRAE). Study outcomes were correlated by aneurysm morphology that was within or outside of the recommended device IFU. chi2 and Kaplan Meier methods were used for analysis. RESULTS Grafts implanted included 177 Cook Zenith (CZ, 31%), 111 Gore Excluder (GE, 20%), and 277 Medtronic AneuRx (MA, 49%); 39.3% of grafts were placed outside of at least one IFU parameter. Mean follow-up was 30 +/- 21 months and was shorter for CZ (20 months CZ vs 35 and 31 months for GE and MA, respectively; P < .001). Overall actuarial 5-year freedom from aneurysm-related death, reintervention, and GRAE was similar among devices. CZ had a lower number of graft migration events (0 CZ vs 1 GE and 9 MA); however, there was no difference between devices on actuarial analysis. Combined GRAE was lowest for CZ (29% CZ, 35% GE, and 43% MA; P = .01). Graft placement outside of IFU was associated with similar 5-year freedom from aneurysm-related death, migration, and reintervention (P > .05), but a lower freedom from GRAE (74% outside IFU vs 86% within IFU; P = .021), likely related to a higher incidence of graft thrombosis (2.3% outside IFU vs 0.3% within IFU; P = .026). The differences in outcome for grafts placed within vs outside IFU were not device-specific. CONCLUSION EVAR performed with three commercially available devices provided similar clinically relevant outcomes at 5 years, although no graft migration occurred with a suprarenal fixation device. As anticipated, application outside of anatomically specific IFU variables had an incremental negative effect on late results, indicating that adherence to such IFU guidelines is appropriate clinical practice.

Surgical Management of Thrombotic Acute Intestinal Ischemia

ObjectiveTo evaluate the University of Kentucky experience in treating acute intestinal ischemia to elucidate factors that contribute to survival. Summary Background DataAcute intestinal ischemia is reported to have a poor prognosis, with survival rates ranging from 0% to 40%. This is based on several reports, most of which were published more than a decade ago. Remarkably, there is a paucity of recent studies that report on current outcome for acute mesenteric ischemia. MethodsA comparative retrospective analysis was performed on patients who were diagnosed with acute intestinal ischemia between May 1993 and July 2000. Patients were divided into two cohorts: nonthrombotic and thrombotic causes. The latter cohort was subdivided into three etiologic subsets: arterial embolism, arterial thrombosis, and venous thrombosis. Patient demographics, clinical characteristics, risk factors, surgical procedures, and survival were analyzed. Survival was compared with a collated historical series. ResultsAcute intestinal ischemia was diagnosed in 170 patients. The etiologies were nonthrombotic (102/170, 60%), thrombotic (58/170, 34%), or indeterminate (10/170, 6%). In the thrombotic cohort, arterial embolism accounted for 38% (22/58) of the cases, arterial thrombosis for 36% (21/58), and venous thrombosis for 26% (15/58). Patients with venous thrombosis were younger. Venous thrombosis was observed more often in men; arterial thrombosis was more frequent in women. The survival rate was 87% in the venous thrombosis group versus 41% and 38% for arterial embolism and thrombosis, respectively. Compared with the collated historical series, the survival rate was 52% versus 25%. ConclusionsThese results indicate that the prognosis for patients with acute intestinal ischemia is substantially better than previously reported.

A multicenter clinical trial of endovascular stent graft repair of acute catastrophes of the descending thoracic aorta

OBJECTIVE Thoracic endovascular aortic repair (TEVAR) is applicable to a spectrum of thoracic aortic pathology with half of the procedures performed world-wide for indications other than degenerative aneurysm of the descending thoracic aorta (DTA). This multicenter, prospective study queried perioperative and one-year results of TEVAR using the commercially available GORE TAG device, in the treatment of acute complicated Type B dissection (cTBD), traumatic aortic tear (TT), and ruptured degenerative aneurysm (RDA) of the DTA. METHODS This prospective, non-randomized, literature controlled study included 59 patients; cTBD, n = 19; RDA, n = 20; TT, n = 20. The primary end-point was the composite of death and total paraplegia in subjects at <or= 30 days post-treatment compared with a cohort from current literature. Secondary end-points included adverse events related to device, procedural and systemic complications, and one-year survival. RESULTS All 59 patients had successful endoprosthesis deployment. Fifteen of 19 (79%) patients in the cTBD group had either rupture or malperfusion syndromes at presentation. Combined 30-day mortality/paraplegia rate was 13.6% (8/59), with seven (11.9%) deaths (cTBD [3], RDA [3] and TT [1]) and 1 (TT, 1.7%) case of paraplegia. The primary end-point for the TEVAR cohort was significantly lower (P = .008) when compared with a composite literature control of 800 patients (combined 30-day mortality/paraplegia of 29.6%). Thirty-day complications of any nature occurred in 48 (81%) patients; 11 (18.6%) were device related, and 43 (73%) experienced one or more systemic adverse events. Six (10%) patients required additional TEVAR implantations and 3 (5%) patients (one in each pathology group) required conversion to open surgery. Seventeen (29%) patients had endoleaks of any kind or degree through 30 days; cTBD (7), TT (2), RDA (8). Nine patients (15.3%) had perioperative strokes with two resultant deaths. During mean follow-up time of 409 +/- 309 days, an additional 12 patients died, one patient required open conversion (cTBD), and two patients had major device related events. Actuarial survival at one year was 66% (range, 52%-77%) for the entire cohort; (cTBD) 79% (range, 53%-92%), (TT) 79% (range, 53%-92%) and (RDA) 37% (range, 16%-59%). On regression analysis, age at treatment (1.05 [range, 1.01-1.09]; P = .008) and chronic obstructive pulmonary disease (COPD) (4.3 [range, 1.3-14.4]; P = .02) were predictive of death at one year. CONCLUSION This study confirmed treatment advantages for TEVAR for thoracic aortic catastrophes when compared with literature-based results of open repair. One-year treatment results indicate a low incidence of graft-related complications. TEVAR is the preferred initial treatment for the DTA catastrophes studied herein.

Aortic remodeling after endovascular repair of acute complicated type B aortic dissection

OBJECTIVE The role of thoracic endovascular aortic repair (TEVAR) in the management of acute type B aortic dissection remains undefined. Entry tear coverage during the acute phase is an appealing method to treat acute complications, and by inducing false lumen thrombosis, might also prevent late aneurysm formation. This study evaluated structural changes by serial computed tomography (CT) in the thoracic aorta after TEVAR performed for acute complicated aortic dissection. METHODS Between August 2005 and October 2007, 33 patients with complicated acute type B aortic dissection were treated with TEVAR (19 from a prospective industry sponsored trial, 14 from our institution). CT images obtained preprocedurally (PP), at 1 month (1M), and 1 year (1Y) were evaluated for each patient. Four patients with no postprocedural imaging were excluded. The largest diameters of the thoracic aorta, dissection true lumen, and false lumen were recorded at each time point. Changes in total aortic and true and false lumen diameters were evaluated using a mixed effect analysis of variance model of repeated measures. RESULTS The average age was 58 years (range, 38-87 years); 26 (81%) were male. Indications for TEVAR included malperfusion syndrome in 17 (53%), refractory hypertension in 14 (44%), impending rupture in 12 (28%), and refractory pain in 14 (44%); 19 (59%) had more than one indication. The average length of aorta covered was 19.5 cm (range, 10-29.3 cm). The maximum aortic diameter decreased over time (P = .04) and averaged 39.9 (PP), 41.3 (1M), and 34.8 mm (1Y). The true lumen diameter increased over time (P = .02) and averaged 23.7 (PP), 29.0 (1M), and 31.1 mm (1Y). The false lumen diameter decreased (P = .046) and averaged 19.5 (PP), 12.1 (1M), and 9.6 mm (1Y). Partial or complete thrombosis of the false lumen along the stented segment of aorta was recorded in 87% (PP), 93% (1M), and 88% (1Y). CONCLUSIONS TEVAR of acute complicated aortic dissection appears to promote early aortic remodeling. Nearly 90% of patients maintained at least partial false lumen thrombosis at 1 year. Because continued false lumen patency correlates strongly with late aneurysm formation, such favorable remodeling is considered a surrogate for prevention of late aneurysm, but longer follow-up is required.

Infrapopliteal balloon angioplasty for the treatment of chronic occlusive disease

OBJECTIVE There is little documentation of the effectiveness of percutaneous balloon angioplasty (PTA) of infrapopliteal vessels for the treatment of chronic lower extremity ischemia. This study reviewed our recent experience with infrapopliteal PTA in a large series of patients to determine its effectiveness as a treatment modality. METHODS All patients undergoing primary infrapopliteal PTA from March 2002 to June 2006 were included. Primary study end points were primary patency, assisted patency, limb salvage, and patient survival assessed by Kaplan-Meier life-table analysis. Factors predictive of PTA failure and patient longevity were evaluated by multivariate methods. RESULTS There were 155 PTAs undertaken in 144 patients (70% men; mean age, 74 years), with critical limb ischemia (86%), diabetes (66%), and renal insufficiency (45%). Infrapopliteal lesions were classified as TransAtlantic Inter-Society Consensus A (7%), B (18%), C (39%), and D (35%). PTA was confined to the infrapopliteal segment in 40 (26%), and 115 (74%) underwent multilevel treatment. Five patients (3%) received stents. Technical success was 95%. The 30-day mortality was 2%, and major morbidity was 3%. The mean follow-up was 22 months (range, 0-54 months). The 40-month actuarial primary patency was 62% (standard error, 5%), with assisted patency (infrapopliteal re-PTA, 25 [16%]) of 90%. Interval conversion to bypass surgery occurred in seven (5%). Nonhealing ulcers occurred in 118 patients (76%), of which 76 (64%) healed during follow-up. Of the 42 unhealed ulcers, 15 (13%) required major amputations for a 40-month limb salvage of 86.2%. Multivariate predictors that were negative for primary patency included 0/1 vessel runoff (P = .01), critical limb ischemia (P = .002), and dialysis (P = .03). Negative predictors of limb salvage included dialysis (P = .007) and failure to improve runoff to the foot (P = .006). At 40-months, patient survival was 54%, with negative predictors including severe pulmonary disease (P = .01), coronary artery disease (P = .04), and renal insufficiency (P < .001). CONCLUSIONS Infrapopliteal angioplasty can be performed safely with favorable results in patients with limited longevity. Primary patency is related to disease extent. Secondary interventions may be necessary to maintain clinical success. These data indicate that PTA should be considered as initial therapy for infrapopliteal occlusive disease in patients with lower extremity ischemia.

Management of diseases of the descending thoracic aorta in the endovascular era: a Medicare population study.

Objective:Prospective trials have shown improved perioperative outcomes with endovascular repair of thoracic aortic (TEVAR) pathologies compared with conventional surgery (OPEN). There are no long-term population data detailing the impact of TEVAR on practice patterns and results of treatment of descending thoracic aortic pathology (DTA), which are the goal of this study. Methods:All procedures performed on the DTA captured in the Medicare database from 2004 to 2007 were identified by ICD-9 codes and stratified into OPEN and TEVAR cohorts. Outcomes included perioperative mortality (&khgr;2) and 5-year actuarial survival. Results:There were 11,166 patients identified (4838 [43%] TEVAR vs. 6328 [57%] OPEN) with 7247 (65%) nonruptured, degenerative thoracic aortic aneurysms (TAA), 2701 (24%) descending aortic dissections, 1033 (9%) thoracic aortic ruptures, and 185 (2%) traumatic aortic tears. The distribution of cases changed significantly during the study period (P < 0.0001) with an increase in TEVAR, decrease in OPEN, and increase in total cases over time (Table 1). The perioperative mortality was lower in the TEVAR group for the entire population (360 [7.4%] TEVAR vs. 1175 [18.5%] OPEN, P < 0.0001), and for the individual pathologies: TAA (182/3529 [5%] TEVAR vs. 451/3718 [12%] OPEN, P < 0.001), dissections (76/833 [9%] TEVAR vs. 399/1868 [21%] OPEN, P < 0.001) and ruptures (87/368 [24%] TEVAR vs. 298/665 [45%] OPEN, P < 0.0001). The Kaplan–Meier curve significantly favored TEVAR for the entire cohort because of the early mortality of the OPEN cohort but the curves converged by 5 years. The 5-year survival by indication was: entire population (53.4% TEVAR vs. 53.3% OPEN, P < 0.0001), TAA (55.8% TEVAR vs. 59.7% OPEN, P = 0.84), dissection (58.2% TEVAR vs. 50.6% OPEN, P < 0.0001), ruptures (23.3% TEVAR vs. 25.3% OPEN, P = 0.001), and trauma (62.9% TEVAR vs. 50.9% OPEN, P = 0.12). Conclusion:There has been a significant increase in the use of TEVAR for management of diseases of the DTA. TEVAR offers a significant perioperative survival advantage when compared with OPEN regardless of the indication for repair. However, in the Medicare population, the 5-year survival is similar between the 2 cohorts.

Thoracoabdominal aneurysm repair: Hybrid versus open repair

OBJECTIVE Hybrid repair of thoracoabdominal aortic aneurysms (TAAA) may reduce morbidity and mortality in high-risk candidates for open repair. This study reviews the outcomes of hybrid TAAA repair for Crawford extent I-III TAAA in high-risk patients in comparison to patients who underwent concurrent open TAAA repair. METHODS During the interval from June 2005 to December 2007, a total of 23 high-risk patients with TAAA (type I: 9 [39%], II: 5 [22%], and III: 9 [39%]) underwent renal and/or mesenteric debranching (11 [48%] with four vessel debranching) with subsequent placement of a thoracic stent graft; 77 patients underwent open TAAA repair (type I: 13 [17%], II: 11 [14%], III: 27 [35%], and IV: 26 [34%]) during the same interval. The primary high-risk criteria for hybrid TAAA included advanced age/poor functional status (n = 14), major pulmonary dysfunction (n = 8), and technical consideration (prior thoracic aortic aneurysm repair [n = 4] or prior thoracoabdominal aneurysm repair [n = 2] and obesity [n = 2]) with 6 patients having overlapping high-risk criteria. Composite (30-day) mortality and/or permanent paraplegia (PP) were the major study endpoints. RESULTS The hybrid and open TAAA groups had (respectively) no statistical difference in mean age (76.6 vs 72.7 years), aneurysm size (6.51 vs 6.52 cm), and non-elective operation (30.4% vs 26.0%). The hybrid group had a higher mean Society for Vascular Surgery (SVS) risk score (9.1 vs 6.0; P <or= .001), incidence of oxygen-dependent chronic obstructive pulmonary disease (COPD) (34.8% vs 2.6%; P <or= .001), and prior thoracic (n = 4) or thoracoabdominal (n = 2) repair (26.1% vs 1.3%; P <or= .001). Composite mortality and/or PP was doubled in the hybrid group (21.7% vs 11.7%; P = .33). The rate of any type of reoperation was higher in hybrid TAAA repair (39.1% vs 20.8%; P = .03). One year actuarial survival for both groups was comparable (hybrid, 68 +/- 12%; open, 73 +/- 6%). A total of 5/23 (22%) hybrid TAAA patients developed an endoleak (type I: 3/23 and type II: 2/23) with 3 requiring endovascular re-intervention. A total of 7/70 (10%) visceral/renal bypass grafts were noted to be occluded during follow-up (1 superior mesenteric artery, 1 celiac, and 5 renal). Examination of patients with an SVS risk score <or=8 (mean SVS risk score in hybrid 6.2 [n = 10] vs 5.5 [n = 68] in open; P = .27) revealed the hybrid group had a higher incidence of composite mortality and/or PP (40% vs 10.3%; P = .03). CONCLUSION Hybrid TAAA repair in high-risk patients has significant morbidity and mortality suggesting a non-interventional approach may be appropriate in many such patients. The morbidity and mortality of the hybrid TAAA repair was substantial even in lower risk patients (SVS risk score <or=8), albeit patient numbers were small. Prospective study in comparable patient risk cohorts is required to define the role of hybrid TAAA repair.

Neuroprotection During Carotid Artery Stenting Using the GORE Flow Reversal System: 30-Day Outcomes in the EMPiRE Clinical Study

Background: Each of the embolic protection devices used in carotid artery stenting (CAS) has advantages and disadvantages. The prospective, multicenter, single‐arm EMPiRE Clinical Study investigated a proximally placed device (GORE Flow Reversal System) that provides distal neuroprotection during CAS by reversing blood flow in the internal carotid artery, thereby directing emboli away from the brain. Methods: The study evaluated 30‐day outcomes in 245 pivotal high‐surgical‐risk patients (mean age, 70 years; 32% symptomatic; 16% ≥80‐years old) with carotid stenosis who underwent CAS using the flow reversal system. The primary endpoint was a major adverse event (MAE; stroke, death, myocardial infarction, or transient ischemic attack) within 30 days of CAS. The MAE rate was compared with an objective performance criterion (OPC) derived from CAS studies that included embolic protection. Results: The MAE rate was 4.5% (11 patients; P = 0.002 compared with the OPC). The stroke and death rate was 2.9%. No patient had a major ischemic stroke. Six patients (2.4%) had intolerance to flow reversal. The death and stroke rates in the symptomatic, asymptomatic, and octogenarian subgroups were 2.6, 3, and 2.6%, respectively, meeting American Heart Association guidelines for carotid endarterectomy. Conclusion: The stroke and death rate in this study was among the lowest in CAS trials. The results indicate that the flow reversal system is safe and effective when used for neuroprotection during CAS and that it provides benefits in a broad patient population.