Aortic arch repair today: open repair is best for most arch lesions.

The transverse aortic arch is challenging to repair by either evolving open or emerging endovascular approaches. Contemporary experience in aortic arch repair can be difficult to assess because clinical practice varies substantially among centers with regard to temperature targets for hypothermic circulatory arrest, temperature monitoring sites, circulating perfusate temperatures, cerebral perfusion monitoring techniques, perfusion catheter flow rates, cannulation sites, pH management, and protective pharmacologic agents. Repair of the aortic arch has changed substantially over the last decade; these changes appear to have substantially reduced patient risk. In general, contemporary outcomes of open aortic arch repair are good to excellent. When acute aortic dissection is absent, many centers report early mortality rates below 5%; when acute aortic dissection is present, these rates are doubled or tripled. Not unexpectedly, mortality rates for total transverse aortic arch repair with elephant trunk or frozen elephant trunk approaches are greater than those for hemiarch repair (7-17% vs. 3-4%). In contemporary reports of mixed hemiarch and total arch repairs for aortic aneurysm, several authors report early mortality rates and stroke rates below 5%. Surprisingly, mortality rates for reoperation are not unlike those for primary repair and range from 8% to 9%; however, the risk of stroke appears somewhat greater and ranges from 5% to 6%.

Quality assessment in open surgical repair of thoracic aortic disease.

Risk-prediction and quality-assurance models facilitate comparison of surgeons, institutions, and emerging alternative technologies. With comparative context, the most meaningful outcomes for thoracic aortic (TA) repair can be identified, evaluated, and adopted to improve open TA repair among a variety of providers; moreover, open TA repair can be more accurately compared to endovascular TA repair. Although the EuroSCORE risk-stratification model was not specifically designed for TA repair, it is largely suitable for this purpose despite the aged dataset from which it was developed. However, such prediction models could be improved by expanding their end points to include not only mortality but other life-altering adverse events, such as paraplegia, stroke, and renal failure. Population-based studies may be useful in establishing trends and should be conducted in a fashion that will enhance their external applicability; procedure-volume studies are often limited as comparative benchmarks. Additionally, experienced centers have great value because they can report the outcomes of large numbers of cases. Despite a tendency to take on challenging cases, centers of excellence consistently report better outcomes than those observed in population studies. Stratifying reported outcomes for risk level and urgency of repair may have value, because it would avoid penalizing surgeons for taking on complex repairs. For the average patient with few comorbidities, the most durable and established repair should be offered, and the best contemporary success rates should be presented to facilitate that choice.

Analysis of multigenerational families with thoracic aortic aneurysms and dissections due to TGFBR1 or TGFBR2 mutations.

BACKGROUND: Mutations in the transforming growth factor beta receptor type I and II genes (TGFBR1 and TGFBR2) cause Loeys-Dietz syndrome (LDS), characterised by thoracic aortic aneurysms and dissections (TAAD), aneurysms and dissections of other arteries, craniosynostosis, cleft palate/bifid uvula, hypertelorism, congenital heart defects, arterial tortuosity, and mental retardation. TGFBR2 mutations can also cause TAAD in the absence of features of LDS in large multigenerational families, yet only sporadic LDS cases or parent-child pairs with TGFBR1 mutations have been reported to date. METHODS: The authors identified TGFBR1 missense mutations in multigenerational families with TAAD by DNA sequencing. Clinical features of affected individuals were assessed and compared with clinical features of previously described TGFBR2 families. RESULTS: Statistical analyses of the clinical features of the TGFBR1 cohort (n = 30) were compared with clinical features of TGFBR2 cohort (n = 77). Significant differences were identified in clinical presentation and survival based on gender in TGFBR1 families but not in TGFBR2 families. In families with TGFBR1 mutations, men died younger than women based on Kaplan-Meier survival curves. In addition, men presented with TAAD and women often presented with dissections and aneurysms of arteries other than the ascending thoracic aorta. The data also suggest that individuals with TGFBR2 mutations are more likely to dissect at aortic diameters <5.0 cm than individuals with TGFBR1 mutations. CONCLUSION: This study is the first to demonstrate clinical differences between patients with TGFBR1 and TGFBR2 mutations. These differences are important for the clinical management and outcome of vascular diseases in these patients.

S100beta correlates with neurologic complications after aortic operation using circulatory arrest.

BACKGROUND: Astrocyte protein S100beta is a potential serum marker for neurologic injury. The goals of this study were to determine whether elevated serum S100beta correlates with neurologic complications in patients requiring hypothermic circulatory arrest (HCA) during thoracic aortic repair, and to determine the impact of retrograde cerebral perfusion (RCP) on S100beta release in this setting. METHODS: Thirty-nine consecutive patients underwent thoracic aortic repairs during HCA; RCP was used in 25 patients. Serum S100beta was measured preoperatively, after cardiopulmonary bypass, and 24 hours postoperatively. RESULTS: Neurologic complications occurred in 3 patients (8%). These patients had higher postbypass S100beta levels (7.17 +/- 1.01 microg/L) than those without neurologic complications (3.63 +/- 2.31 microg/L, p = 0.013). Patients with S100beta levels of 6.0 microg/L or more had a higher incidence of neurologic complications (3 of 7, 43%) compared with those who had levels less than 6.0 microg/L (0 of 30, p = 0.005). Retrograde cerebral perfusion did not affect S100beta release. CONCLUSIONS: Serum S100beta levels of 6.0 microg/L or higher after HCA correlates with postoperative neurologic complications. Using serum S100beta as a marker for brain injury, RCP does not provide improved cerebral protection over HCA alone.

A new predictive model for adverse outcomes after elective thoracoabdominal aortic aneurysm repair.

BACKGROUND: Recent recommendations have emphasized individualized treatment based on balancing a patient's risk of thoracoabdominal aortic aneurysm rupture with the risk of an adverse outcome after surgical repair. The purpose of this study was to determine which preoperative risk factors currently predict an adverse outcome after elective thoracoabdominal aortic aneurysm repair. METHODS: A single, composite end point termed adverse outcome was defined as the occurrence of any of the following: death within 30 days, death before discharge from the hospital, paraplegia, paraparesis, stroke, or acute renal failure requiring dialysis. A risk factor analysis was performed using data from 1,108 consecutive elective thoracoabdominal aortic aneurysm repairs. RESULTS: The incidence of an adverse outcome was 13.0% (144 of 1,108 patients); predictors included preoperative renal insufficiency (p = 0.0001), increasing age (p = 0.0035), symptomatic aneurysms (p = 0.020), and extent II aneurysms (p = 0.0001). These risk factors were used to construct an equation that estimates the probability of an adverse outcome for an individual patient. CONCLUSIONS: This new predictive model may assist in decisions regarding elective thoracoabdominal aortic aneurysm operations. For patients who are acceptable candidates, contemporary surgical management provides favorable results.

Intermittent brachiocephalic vein obstruction secondary to a thymic cyst.

Mediastinal thymic cysts are usually asymptomatic and found incidentally on a routine chest roentgenogram. Rarely, they may cause symptoms of vascular obstruction. A 55-year-old woman presented with intermittent swelling in her left neck. The swelling was positional and was worse while supine and disappeared while upright. Evaluation revealed a thymic cyst causing extrinsic compression of the left brachiocephalic vein. The cyst was resected with complete resolution of the left neck swelling.

Mortality and paraplegia after thoracoabdominal aortic aneurysm repair: a risk factor analysis.

BACKGROUND: Recent recommendations regarding thoracoabdominal aortic aneurysm (TAAA) management have emphasized individualized treatment based on balancing a patient's calculated risk of rupture with their anticipated risk of postoperative death or paraplegia. The purpose of this study was to enhance this risk-benefit decision by providing contemporary results and determining which preoperative risk factors currently predict mortality and paraplegia after TAAA surgery. METHODS: Risk factor analyses based on data regarding 1,220 consecutive patients undergoing TAAA repair from 1986 through 1998 were performed using multiple logistic regression with step-wise model selection. RESULTS: The 30-day mortality rate was 4.8% (58 of 1,220) and the incidence of paraplegia was 4.6% (56 of 1,206). For elective cases, predictors of operative mortality included renal insufficiency (p = 0.0001), increasing age (p = 0.0005), symptomatic aneurysms (p = 0.0059), and extent II aneurysms (p = 0.0054). Extent II aneurysms (p = 0.0023) and diabetes (p = 0.0402) were predictors of paraplegia. CONCLUSIONS: These risk models may assist in decisions regarding elective TAAA operations. For patients who are acceptable candidates, contemporary surgical management provides favorable results.

Cerebrospinal fluid drainage in thoracoabdominal aortic surgery.

Paraplegia caused by spinal cord ischemia remains a devastating complication after surgical repair of thoracoabdominal aortic aneurysms. Cerebrospinal fluid (CSF) drainage has been advocated as a protective adjunct to reduce the incidence of postoperative neurologic deficits. Studies in animals have shown that CSF drainage during thoracic aortic clamping reduces CSF pressure, improves spinal cord blood flow, and prevents paraplegia. Previous retrospective and randomized clinical studies, however, have been inconclusive because of confounding factors and other limitations. A recent prospective randomized trial focusing solely on CSF drainage during repair of extent I and II thoracoabdominal aortic aneurysms indicated an 80% reduction in the relative risk of paraplegia and paraparesis in patients who received this adjunct. Consequently, CSF drainage has emerged as an important addition to the multimodality strategy for preventing postoperative spinal cord deficits.

Surgical techniques. Thoracoabdominal aorta.

Patients presenting with impending rupture of a thoracoabdominal aortic aneurysm require emergency operative repair. To prevent rupture and its associated mortality, elective repair of thoracoabdominal aortic aneurysms exceeding 5.5 cm to 6.0 cm in diameter is recommended in patients with adequate physiologic reserve. Similarly, surgery should be considered for patients with smaller symptomatic aneurysms. Atypical symptoms have been associated with rupture, therefore, they require thorough evaluation. Whether the aortic conditions are caused by medial degenerative disease or chronic aortic dissection, surgical techniques allow for graft repair of thoracoabdominal aortic aneurysms with low mortality and morbidity rates. Although surgery is usually avoided in patients with acute distal aortic dissection, operative intervention is occasionally required when complications develop. Patients with acute aortic dissection complicated by impending rupture of the thoracoabdominal segment require graft repair to restore aortic integrity; although the mortality rate is acceptable, the incidence of postoperative paraplegia approaches 20% in this setting. For patients presenting with ischemic complications of acute distal aortic dissection, less-extensive surgical options have been effective in restoring perfusion. In experienced centers, overall operative survival rate following thoracoabdominal aortic surgery can exceed 92%. Retrospective data suggest that left heart bypass reduces the incidence of paraplegia following extensive thoracoabdominal aortic repairs. Although recent advances have led to improved outcomes, paraplegia continues to occur regardless of the strategy used. The prevention of spinal cord ischemia during thoracoabdominal aortic surgery, therefore, will remain a focus of controversy and investigation, just as it was more than 4 decades ago.

Left heart bypass reduces paraplegia rates after thoracoabdominal aortic aneurysm repair.

BACKGROUND: The optimal strategy for spinal cord protection during thoracoabdominal aortic aneurysm (TAAA) repair remains unclear. We evaluated the protective effect of left heart bypass (LHB) during repair of extensive TAAAs. METHODS: During a 12-year period, 710 patients had repair of extent I or II TAAAs. Left heart bypass was used in 312 (43.9%) patients. This group was retrospectively compared with 398 (56.1%) patients who had operations without LHB. RESULTS: The overall 30-day survival rate was 94.8% (673 patients). In 42 patients, (6.0%) paraplegia or paraparesis developed. In patients with extent I TAAAs, paraplegia and paraparesis rates in LHB (6 of 123, 4.9%) and non-LHB (9 of 246, 3.7%) groups were similar (p = 0.576) despite longer aortic clamp times in the former group. In patients with extent II TAAAs, the LHB group had a lower incidence of paraplegia or paraparesis (9 of 189, 4.8%) compared with the non-LHB group (18 of 137, 13.1%; p = 0.007). CONCLUSIONS: Left heart bypass reduced the risk of paraplegia and paraparesis in patients who had repair of extent I and II TAAAs.

Management of thoracic aortic graft infections.

BACKGROUND: We reviewed our experience managing patients with thoracic aortic graft infections to evaluate their clinical characteristics and outcomes of treatment. METHODS: Records of 20 consecutive patients with thoracic aortic graft infections managed over a 7 year period were retrospectively reviewed. Current follow-up status was obtained for all survivors. RESULTS; Nineteen patients (95%) underwent surgical treatment. Graft excision and in situ replacement were performed using Dacron grafts (10/19, 53%) or cryopreserved homografts (5/19, 26%). Three pseudoaneurysms were managed by debridement and primary repair. Although 30 day postoperative survival was 89% (17/19), in-hospital mortality occurred in 8 patients (42%). Infected thoracoabdominal aortic grafts were universally fatal. Of 6 patients with infected composite valve grafts, both patients who received new composite valve grafts died and all 4 who received homografts survived (p = 0.067). CONCLUSIONS: Infections involving thoracic aortic grafts continue to carry a high mortality rate, especially in patients with polymicrobial infections, thoracoabdominal aortic graft infections, and composite valve graft infections. Use of homografts in the latter situation may improve outcome.

Initial experience with the Nikkiso centrifugal pump during thoracoabdominal aortic aneurysm repair.

PURPOSE: Several centers use atriodistal bypass (ADB) as a protective adjunct against distal ischemia during extensive thoracoabdominal aortic aneurysm (TAAA) repair. Most current ADB circuits use indirect-drive centrifugal pumps. The purpose of this report is to describe our initial clinical experience with the Nikkiso pump, a more compact direct-drive centrifugal pump recently developed at Baylor, for ADB during TAAA repair. METHODS: The Nikkiso pump was used for ADB perfusion in 10 consecutive patients during graft repair of TAAAs (six Crawford extent I and four extent II). Two patients had aortic dissection. In the four patients who had extent II repairs, selective renal and visceral perfusion was also performed with the Nikkiso pump. RESULTS: No mechanical pump malfunctions or adverse events related to the device occurred. All 10 patients survived and were discharged from the hospital. No patient had paraplegia after surgery. Two patients had delayed lower extremity weakness after undergoing extent I repairs; both recovered and were ambulating at the time of discharge. No complications were associated with bleeding or cerebral, respiratory, renal, or hepatic function. CONCLUSIONS: Our initial experience with the Nikkiso centrifugal pump during TAAA repair demonstrated excellent pump function that provided sufficient flow for both distal aortic and selective organ perfusion. The prevention of permanent spinal cord injury and distal organ failure was successful in this group.

Thoracoabdominal aortic aneurysm repair in patients with single kidney.

Data were analyzed from 581 consecutive cases of thoracoabdominal aortic aneurysm (TAAA) repairs. Preoperatively, 32 patients (6%) had only one functioning kidney (single-kidney group), and 549 patients (94%) had tow functioning kidneys (reference group). The patients' mean age was higher in the reference group (64.9 years, range: 21-85) than in the single-kidney group (63.2 years, range: 38-79); p < 0.05. However, there was a significantly higher incidence of hypertension (97% versus 78%), coronary artery disease (50% versus 34%), and renal artery stenosis ipsilateral to functioning kidneys (88% versus 26%) in the single-kidney group than in the reference group; p < 0.05. Preoperatively, renal insufficiency (serum creatinine > or = 2.5 mg/dl or patients on dialysis) was present in four patients (13%) in the single-kidney group and in 21 patients (4%) in the reference group; p < 0.05. In the former group, the unilateral loss of kidney function was secondary to atrophy in 30 patients (94%) and agenesis in two patients (6%). The simple clamp-open distal anastomosis technique was employed in the majority of the cases in the single-kidney group (91%) and in the reference group (83%); p > 0.05. Renal artery endarterectomy or bypass ipsilateral to functioning kidneys was performed on 18 patients (56%) in the single-kidney group and 68 patients (12%) in the reference group; p < 0.05. Renal perfusion with cold Ringer's lactate solution was done in 18 cases (56%) in the single-kidney group and 228 cases (42%) in the reference group; p > 0.05. There was no difference in the operative mortality (9% versus 7%) and the incidence of paraplegia/paraparesis (6% versus 5%) between the single-kidney group and the reference group; p > 0.05. Postoperatively, new onset renal insufficiency developed in 10 patients (31%) in the single-kidney group, and 58 patients (11%) in the reference group; p < 0.05. In the single-kidney group, four patients (13%) had mild renal dysfunction (serum creatinine > or = 2.5 mg/dl), and two patients (6%) were on dialysis on discharge. Notably, there was no significant difference in the incidence of renal insufficiency on admission compared to the incidence of renal insufficiency on discharge in the single-kidney group (13% versus 19%; p > 0.05). TAAA repair in patients with one functioning kidney can be performed safely. Postoperative renal insufficiency can be managed successfully in the majority of patients.

Repair of thoracoabdominal aortic aneurysms in octogenarians.

BACKGROUND: Reports on octogenarians undergoing coronary revascularization, valve replacement, and abdominal aneurysmorrhaphy demonstrate little increase in operative risk during elective procedures. However, the mortality in this group of patients increases rapidly when urgent or emergent procedures are performed. We analyzed the outcome of patients in their ninth decade of life undergoing repair of thoracoabdominal aortic aneurysms. METHODS: A retrospective review of 39 consecutive octogenarians undergoing repair of thoracoabdominal aortic aneurysms. RESULTS: Thirty-nine of the past 900 patients with thoracoabdominal aortic aneurysms (5.2%) repaired by us were between the ages of 80 and 89 years. The median age was 84 years with a male-to-female ratio of 1:3. Two of 39 patients (5%) had acute type III dissections, and the remainder had chronic aneurysms. Twelve patients had Crawford extent I aneurysms, whereas 7, 10, and 10 patients were extent II, III, and IV, respectively. The overall in-hospital mortality was 10.3% (4 of 39 patients). Major postoperative complications included paraperesis/paraplegia, 5% (n = 2); renal failure, 18% (n = 7) including hemodialysis in 3 patients; stroke, 5% (n = 2); myocardial infarction or arrhythmia, 18% (n = 7); and respiratory insufficiency, 36% (n = 14) including 4 patients requiring tracheostomy. A univariate analysis of perioperative risk factors was performed using the Fisher's exact test. The need for hemodialysis (p = 0.035), a tracheostomy (p = 0.0001), or a perioperative myocardial infarction (p < 0.001) significantly increased the risk of death. CONCLUSIONS: Repair of thoracoabdominal aortic aneurysms in octogenarians can be performed with acceptable morbidity and mortality. However, survival decreases dramatically with even single system organ failure. An extended period of recovery is usually required in these elderly, high-risk patients.

Successful repair of mega aorta using reversed elephant trunk procedure.

The case reported is of a patient with mega aorta and a symptomatic thoracoabdominal aortic segment. Successful treatment involved resection and graft replacement of the thoracoabdominal segment as an initial procedure using a "reversed elephant trunk" technique, followed by resection and replacement of the ascending aorta and transverse aortic arch as the second stage.

Aortic root replacement: results using the St. Jude Medical/Hemashield composite graft.

BACKGROUND: Aortic root replacement remains a formidable operation. Although perioperative mortality has declined steadily, there is no consensus regarding the preferred method of reconstruction or type of composite to be used. We present our last 2 years' experience with aortic root replacement using the St. Jude Medical/Hemashield composite valve conduit. METHODS: A retrospective review of 52 consecutive patients undergoing aortic root replacement from February 1994 through October 1996 is presented. Both the open/exclusion and Cabrol methods of reconstruction were used. RESULTS: Thirty-one percent of the patients had undergone previous procedures of the aortic root. Thirty-seven percent required aortic arch replacement and 35% required concomitant cardiac or vascular procedures. Perioperative morbidity was low, as was perioperative mortality (3.8%). Both of the deaths that occurred were related to complications with the management of remaining thoracoabdominal aneurysms. CONCLUSIONS: Using meticulous surgical technique and the St. Jude Medical/Hemashield composite valve conduit, one can expect low mortality and complication rates for complex aortic root reconstruction.

Impact of previous thoracic aneurysm repair on thoracoabdominal aortic aneurysm management.

BACKGROUND: The purpose of this study was to determine the impact of previous thoracic aortic aneurysm repair (PTAR) on subsequent thoracoabdominal aortic aneurysm operations. METHODS: A retrospective review of 723 thoracoabdominal aortic aneurysm repairs over a 10-year period facilitated comparison of 179 patients (24.8%) with PTAR and 544 patients (75.2%) without PTAR. RESULTS: Patients with PTAR had more chronic dissections and extensive thoracoabdominal aortic aneurysms, and consequently required longer clamp and ischemic times and more intraoperative transfusions. Patients without PTAR were older, had more preoperative comorbid disease, and had more symptomatic or ruptured aneurysms. Although differences did not reach statistical significance, patients without PTAR tended toward increased in-hospital mortality (8.5% versus 4.5%; p = 0.078) and postoperative paraplegia/paraparesis rates (6.5% versus 2.8%; p = 0.069). More patients without PTAR had cardiac complications (11.3% versus 5.6%; p = 0.028) and required chronic hemodialysis (5.9% versus 1.1%; p = 0.009). CONCLUSIONS: The presence of a PTAR did not adversely affect the outcome of thoracoabdominal aortic aneurysm repair. After thoracic aortic aneurysm repair, life-long radiologic surveillance and early surgical treatment are justified.

Retrograde cerebral perfusion is an effective means of neural support during deep hypothermic circulatory arrest.

With the current available information, the use of RCP for cerebral protection during HCA in the clinical setting will continue to be debated. Laboratory evaluation in a variety of animal models has thus far produced conflicting results and a variety of mixed information. Accumulating clinical evidence has confirmed that RCP is safe, provided flow rates and central venous (intracerebral) pressures are maintained at relatively low levels. The use of RCP is clinically safe and does not incur additional expense. In the event that the only clinical benefits of RCP are the maintenance of cerebral hypothermia and the flushing of air and particulate debris from the arterial circulation, consequently reducing the risk of embolism, then the continued use and investigation of RCP techniques is justified.

Acquired supranuclear ocular motor paresis following cardiovascular surgery.

Acquired supranuclear ocular motor paresis is a rare disorder characterized by impaired saccadic and smooth pursuit eye movements in one or more directions of gaze. Vestibularly induced eye movements, however, are preserved. Six adult patients developed an acquired supranuclear ocular motor paresis following cardiopulmonary bypass surgery. Neuroimaging studies were normal in two patients and were consistent with small vessel ischemia in four patients. The mean cardiopulmonary bypass time was 132.3 min, and mean circulatory arrest time was 38.7 min; these were not outside established norms for this type of surgery. Patients undergoing cardiopulmonary bypass procedures with deep hypothermia are at risk for acquired supranuclear ocular motor paresis, but the development of this syndrome may not be predictable by duration of circulatory arrest or cardiopulmonary bypass times.