Philip J. Hess

Risk factors for perioperative stroke during thoracic endovascular aortic repairs (TEVAR).

PURPOSE To determine the clinical and anatomical risk factors for cerebrovascular accidents (CVA) in patients undergoing thoracic endovascular aortic repair (TEVAR). METHODS Between September 2000 and December 2006, 196 patients (135 men; mean age 68.6+/-13.5 years, range 17-92) underwent TEVAR for a variety of aortic pathologies. The majority (156, 79.6%) were treated with the TAG stent-graft. Demographics, pathologies, intraoperative procedure-related measures, device usage, and postoperative outcomes were assessed. CVA was defined as a new focal or global neurological (motor or sensory) deficit lasting >48 hours associated with acute intracranial abnormalities on computed tomography or magnetic resonance brain imaging. Spinal cord ischemia was excluded. In a subset of patients with planned left subclavian artery (LSA) coverage and an incomplete circle of Willis or a dominant left vertebral artery, prophylactic carotid-subclavian bypasses were performed. RESULTS Nine (4.6%) patients suffered a CVA. Factors not predictive of a CVA on univariate analysis included aortic pathology, urgency of repair, ASA classification, type of anesthesia, blood loss, procedure time, and device used. Proximal extent of repair (with or without extra-anatomical revascularization) was significantly associated with a higher incidence of strokes (zones 0-2 versus 3-4, p=0.025). Five (55.6%) patients with a CVA had documented intraoperative hypotension (systolic blood pressure<80 mmHg). Additionally, while 2 patients had hemispheric infarcts, 5 had acute posterior circulation infarcts involving the cerebellum and brainstem; a single patient had both anterior and posterior circulation infarcts. Seven of the CVA patients had proximal coverage of the thoracic aorta in zones 0-2; of these, 6 had posterior circulation infarcts. Selective LSA revascularization based on preoperative cerebrovascular imaging resulted in lower rates of CVA (6.4% to 2.3%, p=0.30) and posterior circulation infarcts (5.5% to 1.2%, p=0.13). CONCLUSION Proximal extent of repair may serve as a surrogate marker for greater severity of degenerative disease of the aortic arch. Avoidance of intraoperative hypotension and preservation of antegrade vertebral perfusion may be important in prevention of posterior circulation strokes.

The relationship between visceral ischemia, proinflammatory cytokines, and organ injury in patients undergoing thoracoabdominal aortic aneurysm repair.

ObjectivesPlasma proinflammatory, anti-inflammatory cytokine, and soluble tumor necrosis factor (TNF) receptor concentrations were examined in hospitalized patients after abdominal and thoracoabdominal aortic aneurysm (TAAA) repair, with and without left atrial femoral bypass. Changes in plasma cytokine concentrations were related to the duration of visceral ischemia and the frequency rate of postoperative, single, or multiple system organ dysfunction (MSOD). DesignProspective, observational study. SettingTwo academic referral centers in the United States and The Netherlands. PatientsWe included 16 patients undergoing TAAA repair without left atrial femoral bypass, 12 patients undergoing TAAA repair with left atrial femoral bypass, and nine patients undergoing infrarenal aortic aneurysm repair. Measurements and Main ResultsTimed, arterial blood sampling for proinflammatory and anti-inflammatory cytokine and soluble TNF receptor concentrations (p55 and p75), and prospective assessment of postoperative single and MSOD. Plasma appearance of TNF-&agr;, interleukin (IL)-6, IL-8, and IL-10 peaked 1 to 4 hrs after TAAA repair, and concentrations were significantly elevated compared with infrarenal abdominal aortic aneurysm repair (p < .05). Left atrial femoral bypass significantly reduced the duration of visceral ischemia (p < .05) and the systemic TNF-&agr;, p75, and IL-10 responses (p < .05). Plasma TNF-&agr; concentrations >150 pg/mL were more common in patients with extended visceral ischemia times (>40 mins). Additionally, patients with early peak TNF-&agr; concentrations >150 pg/mL and IL-6 levels >1,000 pg/mL developed MSOD more frequently than patients without these elevated plasma cytokine levels (both p < .05). ConclusionsThoracoabdominal aortic aneurysm repair results in the increased plasma appearance of TNF-&agr;, IL-6, IL-8, IL-10, and shed TNF receptors. The frequency and magnitude of postoperative organ dysfunction after TAAA repair is associated with an increased concentration of the cytokines, TNF-&agr;, and IL-6 and the increased plasma levels of these cytokines appear to require extended visceral ischemia times.

Extent of Aortic Coverage and Incidence of Spinal Cord Ischemia After Thoracic Endovascular Aneurysm Repair

BACKGROUND Risk factors for spinal cord ischemia (SCI) after thoracic endovascular aneurysm repair (TEVAR) remain unclear. Aortic coverage was examined as a risk factor for SCI using quantitative three-dimensional computed tomography angiography (CTA) analysis. METHODS The medical records, radiographic imaging studies, and a prospectively maintained database of all TEVAR procedures performed during a 7-year period were retrospectively reviewed. Preoperative anatomic dimensions and postoperative graft path lengths were measured from CTAs using curved planar and orthogonal multiplanar reformations along centerline paths. SCI was defined as transient or permanent lower extremity neurologic deficit without associated intracerebral hemispheric events. RESULTS Of 326 TEVAR cases, 241 patients (74%) had satisfactory imaging. Thirty-three (10%) had SCI. These patients were older (72.7 +/- 10.6 vs 64.7 +/- 15.8 years, p = 0.005) and had longer intraoperative procedure times (137 +/- 65 vs 113 +/- 68 minutes, p = 0.05). Despite similar total lengths of native thoracic aorta (295.0 +/- 36.3 vs 283.1 +/- 39.8 mm, p = 0.17), patients with permanent SCI had a greater absolute (260.5 +/- 40.9 vs 195.8 +/- 81.6 mm, p = 0.002) and proportionate (88.8% +/- 12.1% vs 67.6% +/- 24.0%, p = 0.001) length of aortic coverage. The average length of uncovered aorta proximal to the celiac artery in patients with SCI was 17.3 +/- 21.8 mm vs 63.1 +/- 62.9 mm in patients without SCI (p = 0.0006). Neither the patency of the hypogastric arteries nor left subclavian artery was associated with SCI. CONCLUSIONS The extent and distal location (relative to the celiac artery) of aortic coverage were associated with an increased risk of SCI. Prophylactic measures for spinal cord protection should be considered in patients whose thoracic aortas require extensive coverage.

Early outcomes after endovascular management of acute, complicated type B aortic dissection

OBJECTIVES Surgical management of acute, complicated type B aortic dissection is associated with significant morbidity and mortality. This study examined the feasibility and safety of endovascular treatment of this pathology. METHODS We reviewed a prospectively maintained thoracic endovascular database and medical records at a single institution from 2005 to 2007. The study group comprised of acute, complicated type B dissections, defined as duration of symptoms <or=14 days and involving either false lumen rupture, malperfusion, intractable pain, or uncontrolled hypertension. All repairs were performed using the TAG device (W. L. Gore and Associates, Flagstaff, Ariz). Select 30-day or in-hospital outcomes were reported. RESULTS Of the 216 thoracic endovascular aortic aneurysm repairs performed during the study period, 33 (15%) were for acute, complicated type B dissections. There were eight women (24%). The mean age was 61 +/- 15 years. The average duration of symptoms was 2.9 +/- 4.1 (median, 1) days. The indications for repair included rupture in 15 patients (46%) and mesenteric/renal/lower extremity malperfusion in 11 (33%). Mean fluoroscopy time and contrast volume were 30 +/- 16 minutes and 176 +/- 55 mL, respectively. Eight (73%) of 11 patients with malperfusion required branch vessel stenting. The 30-day in-hospital mortality was 21% (7 of 33). Causes of death included cardiac arrest in 3, progressive multisystem organ failure in 2, rupture in 1 and unknown in 1. At least one major complication occurred in 76% of the patients, including respiratory failure in 11 (33%), permanent spinal cord ischemia in 5 (15%), renal failure requiring dialysis in 4 (12%), and stroke in 4 (12%). The mean postoperative length of stay was 17.2 +/- 16.5 days, and only 14 (42%) were discharged to home. CONCLUSIONS Emergency endovascular repair of acute, complicated type B dissection is associated with significant mortality and morbidity. The overall role of this therapy in the treatment of this lethal problem should be better defined and compared with other surgical or interventional options before being generally adopted.

Exogenously administered interleukin-10 decreases pulmonary neutrophil infiltration in a tumor necrosis factor–dependent murine model of acute visceral ischemia

INTRODUCTION Visceral ischemia and reperfusion associated with thoracoabdominal aortic aneurysm (TAAA) repair results in lung injury, which appears to be mediated in part by proinflammatory cytokines. The purpose of this study was to determine the effect of exogenous administration of the antiinflammatory cytokine, recombinant human IL-10 (rhIL-10), on proinflammatory cytokine production (IL-6 and TNF alpha) and pulmonary neutrophil infiltration after acute visceral ischemia-reperfusion. METHODS Two hours before 25 minutes of supraceliac aortic occlusion, 80 C57BL/6 mice (20 to 22 g) received an intraperitoneal injection of rhIL-10 (0.2 microgram [n = 20], 2 micrograms [n = 20], 5 micrograms [n = 25], or 20 micrograms [n = 15]), and 16 mice received murine anti-IL-10 IgM 200 micrograms. Twenty-five additional mice underwent visceral ischemia-reperfusion without treatment (controls), and 16 mice underwent laparotomy without aortic occlusion (sham). RESULTS Pretreatment with exogenous rhIL-10 resulted in significant reductions in lung neutrophil infiltration with 0.2 microgram, 2 micrograms, and 5 micrograms per mouse of rhIL-10 compared with lung neutrophil levels in control mice that underwent acute visceral ischemia-reperfusion alone (p < 0.05). In addition, serum TNF alpha was detected in 50% of control mice and in 75% of mice that received murine anti-IL-10, but in none of the mice that received rhIL-10 (2 micrograms per mouse) or the mice that underwent sham operative procedures (p < 0.05 by chi 2 analysis). CONCLUSION Exogenous IL-10 limits pulmonary neutrophil recruitment and the appearance of TNF alpha in this model of visceral ischemia-reperfusion injury. Thus the use of exogenous IL-10 may offer a novel therapeutic approach to decrease the complications that are associated with TAAA repair.

Efficacy of thoracic endovascular stent repair for chronic type B aortic dissection with aneurysmal degeneration

BACKGROUND The Food and Drug Administration has approved devices for endovascular management of thoracic endovascular aortic aneurysm repair (TEVAR); however, limited data exist describing the outcomes of TEVAR for aneurysms attributable to chronic type B aortic dissection (cTBAD). This study was undertaken to determine the results of endovascular treatment of cTBAD with aneurysmal degeneration. METHODS A retrospective analysis of all patients treated for cTBAD with aneurysmal degeneration at the University of Florida from 2004 to 2011 was performed. Computed tomograms with centerline reconstruction were analyzed to determine change in aortic diameter, relative proportions of aortic treatment lengths, and false lumen perfusion status. Reintervention and mortality were estimated using life-tables. Cox regression analysis was completed to predict mortality. RESULTS Eighty patients underwent TEVAR for aneurysm due to cTBAD (mean age [± standard deviation], 60 ± 13 years [male, 87.5%; n = 70]; median follow-up, 26 [range, 1-74] months). Median time from diagnosis of TBAD to TEVAR was 16 (range, 1-72) months. Prior aortic root/arch replacement had been performed in 29% (n = 23) at a median interval of 28.5 (range, 0.5-312) months. Mean preoperative aneurysm diameter was 62.0 ± 9.9 mm. In 75% (n = 60) of cases, coverage was proximal to zone 3, and 24% (n = 19) underwent carotid-subclavian bypass or other arch debranching procedure. Spinal drains were used in 78% (pre-op 71%, n = 57; post-op 6%, n = 5). Length of stay was 6.5 ± 4.7 days with a composite morbidity of 26% and in-hospital mortality of 2.5% (n = 2). Overall neurologic event rate was 17% (spinal cord ischemia 10% [n = 8], with a permanent deficit observed in 6.2% [n = 5]; stroke 7.5%). Aneurysm diameter reduced or stabilized in 65%. The false lumen thrombosed completely within the thoracic aorta in 52%, and reintervention within the treated aortic segment was required in 16% (n = 13).One- and 3-year freedom from reintervention (with 95% confidence interval [CI]) was 80% (range, 68%-88%) and 70% (range, 57%-80%), respectively. Survival at 1 and 5 years was 89% (range, 80%-94%) and 70% (range, 55%-81%) and was not significantly different among patients requiring reintervention or experiencing favorable aortic remodeling. Multivariable analysis identified coronary artery disease (hazard ratio [HR], 6.4; 95% CI, 2.3-17.7; P < .005), prior infrarenal aortic surgery (HR, 8.6; 95% CI, 2.3-31.7; P = .001), and congestive heart failure (HR, 11.9; 95% CI, 1.9-73.8; P = .008) as independent risk factors for mortality. Hyperlipidemia was found to be protective (HR, 0.2; 95% CI, 0.05-0.6; P = .004). No significant difference in predictors of mortality were found between patients who underwent reintervention vs those who did not (P = .2). CONCLUSIONS TEVAR for cTBAD with aneurysmal degeneration can be performed safely but spinal cord ischemia rates may be higher than previously reported. Liberal use of procedural adjuncts to reduce this complication, such as spinal drainage, is recommended. Reintervention is common, but long-term survival does not appear to be impacted by remediation.

Spinal cord ischemia after TEVAR in patients with abdominal aortic aneurysms

OBJECTIVE To examine the incidence of and the anatomic factors that may contribute to spinal cord ischemia (SCI) in patients with a history of abdominal aortic aneurysms (AAA) after thoracic endovascular aortic repair (TEVAR). METHODS The medical records, computed tomography (CT) angiograms, and a prospectively maintained clinical database of all TEVAR patients at a single institution between 2000 and 2007 were reviewed. Select preoperative demographics, thoracoabdominal aortoiliac anatomy, intraoperative procedural variables, and postoperative outcomes were examined. Univariate and multivariate analyses were performed and odds ratio estimates were reported with 95% confidence intervals. RESULTS Of the 261 patients who underwent TEVAR, 27 developed SCI (10%). Thirteen (48%) of these 27 patients were completely reversed with spinal drainage, and 14 (52%) were permanent. Patients with SCI tended to be older (P = .006), male (P = .049), and required more emergent procedures (P = .051) performed under general anesthesia (P = .004). Interestingly, while prior AAA repair (50/261, 19%) alone was not associated with SCI (P = .44), a history of either repaired or unrepaired AAA (101/261, 39%) was a predictor of SCI on multivariate analysis (odds ratio [OR] = 4.35 [1.43, 14.3], P = .10), independent of thoracic aortic coverage (P = .001) and lumbar artery patency (P = .008), both of which were also associated with SCI. CONCLUSION Although the causes of SCI after TEVAR are multifactorial, abdominal aortic anatomy appears to be associated with development of this complication. Patients with either prior AAA repair or those with unrepaired AAA appear to be at increased risk for SCI.

Late Outcomes of a Single-Center Experience of 400 Consecutive Thoracic Endovascular Aortic Repairs

Background— In this study, we report the late outcomes of a large, decade-long single-center thoracic endovascular aortic repair experience. Methods and Results— A prospectively maintained registry and the electronic medical records of 400 consecutive thoracic endovascular aortic repair performed at a tertiary care center were reviewed. The distribution of pathologies treated included aneurysms (198, 49%), dissections (100, 25%), penetrating ulcers (54, 14%), traumatic transections (25, 6%), and other pathologies (23, 6%). Spinal drains were placed prophylactically in 127 cases (32%) of planned extended aortic coverage. There were no acute surgical conversions. Adjunctive surgical procedures were performed on 94 patients (24%). Subclavian revascularizations were performed selectively in only 15% of zone 0 to 2 deployments. The median length of stay was 5 days (limits, 1 and 79 days). Overall 30-day mortality was 6.5% (elective, 2.6%; urgent, 9.5%; and emergent, 20%). Permanent spinal cord ischemia occurred in 4.5% and stroke in 3%. Kaplan-Meier estimates of survival were 82%, 76%, 68%, and 60% and freedom from secondary intervention was 90%, 86%, 81%, and 78% at 6, 12, 24, and 36 months, respectively. Risk factors for mortality included stroke, urgent/emergent repair, age ≥80 years, general anesthesia, and dissection pathology. Conclusions— Thoracic endovascular aortic repair may be used to treat a variety of thoracic aortic pathologies with a very low risk of intraoperative conversion. Overall rates of mortality and neurological complications were relatively low but significantly increased in emergent repairs. There appeared to be a substantial number of late deaths, which may represent a combination of poor patient selection and treatment failures.

Prophylactic nesiritide does not prevent dialysis or all-cause mortality in patients undergoing high-risk cardiac surgery

OBJECTIVES Natriuretic peptides have been shown to improve renal blood flow and stimulate natriuresis. In a recent retrospective trial, we documented that prophylactic use of nesiritide was associated with a 66% reduction in the odds for dialysis or in-hospital mortality at 21 days in patients undergoing high-risk cardiac surgery; therefore, we designed a prospective trial. METHODS This prospective, randomized, clinical trial included 94 patients undergoing high-risk cardiac surgery comparing a 5-day course of continuous nesiritide (at a dose of 0.01 microg x kg(-1) x min(-1) started before surgery) versus placebo. The primary end point was dialysis and/or all-cause mortality within 21 days; secondary end points were incidence of acute kidney injury, renal function, and length of stay. RESULTS Nesiritide did not reduce the primary end point of incidence of dialysis and/or all-cause mortality through day 21 (6.6% vs 6.1%; P = .914). Fewer patients receiving nesiritide had acute kidney injury (defined as an absolute increase in serum creatinine > or = 0.3 mg/dL from baseline or a percentage increase in serum creatinine > or = 50% from baseline within 48 hours) compared with controls (2.2% vs 22.4%; P = .004), and mean serum creatinine was lower in the immediate postoperative period in the nesiritide group (1.18 +/- 0.41 mg/dL vs 1.45 +/- 0.74 mg/dL; P = .028). However, no difference in length of stay was noted (nesiritide 20.73 +/- 3.05 days vs control 21.26 +/- 4.03 days; P = .917). CONCLUSIONS These results do not demonstrate a benefit for prophylactic use of nesiritide on the incidence of dialysis and/or death in patients undergoing high-risk cardiac surgery. Although nesiritide may provide some renal protection in the immediate postoperative period, no effect on length of stay was observed.

Fate of patients with spinal cord ischemia complicating thoracic endovascular aortic repair

OBJECTIVE Spinal cord ischemia (SCI) is a potentially devastating complication of thoracic endovascular aortic repair (TEVAR) that can result in varying degrees of short-term and permanent disability. This study was undertaken to describe the clinical outcomes, long-term functional impact, and influence on survival of SCI after TEVAR. METHODS A retrospective review of all TEVAR patients at the University of Florida from 2000 to 2011 was performed to identify individuals experiencing SCI, defined by any new lower extremity neurologic deficit not attributable to another cause. SCI was dichotomized into immediate or delayed onset, with immediate onset defined as SCI noted upon awakening from anesthesia, and delayed characterized as a period of normal function, followed by development of neurologic injury. Ambulatory status was determined using database query, record review, and phone interviews with patients and/or family. Mortality was estimated using life-table analysis. RESULTS A total of 607 TEVARs were performed for various indications, with 57 patients (9.4%) noted to have postoperative SCI (4.3% permanent). SCI patients were more likely to be older (63.9 ± 15.6 vs 70.5 ± 11.2 years; P = .002) and have a number of comorbidities, including chronic obstructive pulmonary disease, hypertension, dyslipidemia, and cerebrovascular disease (P < .0001). At some point in their care, a cerebrospinal fluid drain was placed in 54 patients (95%), with 54% placed postoperatively. In-hospital mortality was 8.8% for the entire cohort (SCI vs no SCI; P = .45). SCI developed immediately in 12 patients, delayed onset in 40, and indeterminate in five patients due to indiscriminate timing from postoperative sedation. Three patients (25%) with immediate SCI had measurable functional improvement (FI), whereas 28 (70%) of the delayed-onset patients experienced some degree of neurologic recovery (P = .04). Of the 34 patients with complete data available, 26 (76%) reported quantifiable FI, but only 13 (38%) experienced return to their preoperative baseline. Estimated mean (± standard error) survival for patients with and without SCI was 37.2 ± 4.5 and 71.6 ± 3.9 months (P < .0006), respectively. Patients with FI had a mean survival of 53.9 ± 5.9 months compared with 9.6 ± 3.6 months for those without improvement (P < .0001). Survival and return of neurologic function were not significantly different when patients with preoperative and postoperative cerebrospinal fluid drains were compared. CONCLUSIONS The minority of patients experience complete return to baseline function after SCI with TEVAR, and outcomes in patients without early functional recovery are particularly dismal. Patients experiencing delayed SCI are more likely to have FI and may anticipate similar life-expectancy with neurologic recovery compared with patients without SCI. Timing of drain placement does not appear to have an impact on postdischarge FI or long-term mortality.