Thomas M. Beaver

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.

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.

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.

Single-Stage Transmediastinal Replacement of the Ascending, Arch, and Descending Thoracic Aorta

BACKGROUND Aneurysms of the ascending, arch, and descending thoracic aorta are typically managed with two operations. The first stage involves replacement of the ascending and arch aorta leaving a segment of graft in the proximal descending aorta with a mortality and stroke risk of 8%. The second stage involves replacement of the descending aorta with a mortality of 5% and a paraplegia risk of 5% to 10%. Some patients refuse surgical completion and others are at increased risk to undergo the second stage thoracotomy, leaving them with untreated descending thoracic aortic aneurysms vulnerable to rupture. A single-stage transmediastinal operation used in 14 patients is described. METHODS Under circulatory arrest, the descending thoracic aorta is opened. A wire is passed up to the arch and a graft is brought down and secured excluding the descending thoracic aneurysm. The arch vessels are attached as a single patch and the graft is brought forward, replacing the ascending aorta. RESULTS Fourteen patients have undergone single-stage replacement of the ascending, arch, and descending aorta with a 14% mortality rate and 14% incidence of paraplegia. CONCLUSIONS Patients with aneurysms of the ascending, arch, and descending thoracic aorta can be managed with a single operation with comparable mortality and morbidity of the two-stage approach.

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.

Uric acid: a novel risk factor for acute kidney injury in high-risk cardiac surgery patients?

Background: Uric acid has been reported to be a risk factor for the development of chronic kidney disease; however, no study has examined whether uric acid may confer a risk for acute kidney injury. Methods: We investigated the relation between serum uric acid and the incidence of postoperative acute kidney injury in patients undergoing high-risk cardiovascular surgery (cardiac valve and aneurysm surgery). Results: Following cardiovascular surgery, 18 of 58 patients (31%) developed acute kidney injury, with 11 of 24 (45.8%) in the elevated uric acid group (defined as >6 mg/dl) and 7 of 34 (20.5%) in the normal uric acid group (p = 0.05). After controlling for baseline renal function, left ventricular ejection fraction, use of nesiritide, type of surgery, and history of previous surgery, an elevated preoperative uric acid conferred a 4-fold risk for acute kidney injury (OR: 3.98, CI: 1.10–14.33, p = 0.035) and longer hospital stay (36.35 vs. 24.66 days, p = 0.009). Conclusion: This preliminary study suggests that uric acid may be a novel risk factor for acute kidney injury in patients undergoing high-risk cardiovascular surgery.

Arch Debranching Versus Elephant Trunk Procedures for Hybrid Repair of Thoracic Aortic Pathologies

BACKGROUND We compared outcomes of arch debranching (AD) and elephant trunk (ET) techniques when used with thoracic endovascular aortic repair. METHODS A review was performed of consecutive patients with proximal thoracic aortic pathologies repaired with a hybrid approach. RESULTS Between 2005 and 2009, 58 patients underwent first-stage ET (n = 21) or AD (n = 37). Cardiopulmonary bypass was utilized in 100% of ET procedures and 68% of AD procedures (p < 0.01). Circulatory arrest was used in 86% of ET and 27% of AD cases (p < 0.01). The second stage was completed in 76% of ET and 76% of AD patients. Rates of spinal cord ischemia (ET 0 of 21, AD 0 of 37, p = 1.0), stroke (ET 2 of 21, AD 4 of 37, p = 1.0), and 30-day mortality (ET 4 of 21, AD 6 of 37, p = 1.0) were similar. Each group had one major aortic complication between the two stages. Type Ia endovascular leak at 1 and 12 months occurred in 13% ET patients and 4% AD patients at 1 month (p = 0.54) and in 0% ET patients and 4% AD patients at 12 months (p = 1.0). Kaplan-Meier estimates of survival at 1 and 12 months were 90.5% ± 6.4% and 73.1% ± 10% in the ET group, and 86.5% ± 5.6 and 71.6% ± 8.5 in the AD group, respectively (p = 0.68). The risk of a secondary procedure at 1 and 12 months was 76.2% ± 9.3% and 58.7% ± 12% in the ET group, and 71.0% ± 7.8% and 52.8% ± 10% in the AD group, respectively (p = 0.86). CONCLUSIONS Arch debranching achieves equivalent results to standard elephant trunk repair but with a decreased need for cardiopulmonary bypass and circulatory arrest.

Early Outcomes Using the Florida Sleeve Repair for Correction of Aortic Insufficiency due to Root Aneurysms

BACKGROUND The Florida sleeve procedure is a simplified valve-sparing technique for repair of functional type I aortic insufficiency associated with root aneurysms. Midterm outcomes are reported, including standard echocardiographic measurements. METHODS The study included all patients undergoing the Florida sleeve procedure who had at least 2 years of postoperative echocardiographic follow-up. Data were acquired preoperatively and postoperatively at 1 week and 1, 2, and 3 years. Measurements analyzed included left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), and degree of aortic insufficiency. RESULTS Complete echocardiographic data for a mean 32 +/- 6.3 months after repair were available for 18 patients. Mean LVEDD decreased from 51.6 +/- 7.4 to 49.7 +/- 6.3 mm at 1 week (p = 0.05) and 47.1 +/- 6.3 mm at 1 year (p = 0.008), and remained unchanged at 47.2 +/- 6.6 and 47.1 +/- 5.0 mm at 2 and 3 years. Mean LVESD decreased from 35.2 +/- 7.6 to 32.9 +/- 7.0 mm at 1 week (p = 0.002) and 30.7 +/- 5.6 mm at 1 year (p < 0.001), and remained unchanged at 30.9 +/- 6.2 and 31.7 +/- 4.9 mm after 2 and 3 years. The mean grade of aortic insufficiency decreased from 2.61 +/- 0.78 to 1.39 +/- 0.85 mm at 1 week (p < 0.001) and remained 1.39 +/- 0.84 mm at 1 year. Aortic insufficiency increased to 1.72 +/- 0.89 (p = 0.03) at 2 years and decreased to 1.67 +/- 0.50 (p = 0.59, from 1 week postoperatively) at 3 years. CONCLUSIONS The sustained reduction of left ventricular dimensions 3 years after operation suggests the Florida sleeve procedure is a durable valve repair. A minor increase in the degree of aortic insufficiency warrants close follow-up, but the absence of an increase of LVEDD supports continued use of the procedure in closely studied series.