A prospective randomized study of cerebrospinal fluid drainage to prevent paraplegia after high-risk surgery on the thoracoabdominal aorta

The Year in Aortic Surgery: Selected Highlights From 2023

This article reviews the recent and relevant literature to the field of aortic surgery. Specific areas highlighted include outcomes of Stanford type A dissection, management of acute aortic syndromes, management of aortic aneurysms, and traumatic aortic injury. Although the focus was on articles from 2023, literature from prior years also was included, given that this article is the first of a series. Notably, the pertinent sections from the 2022 American College of Cardiology/American Heart Association Guidelines for the Diagnosis and Management Aortic Disease are discussed.

2022 ACC/AHA guideline for the diagnosis and management of aortic disease: A report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

Effect of cerebrospinal fluid drainage pressure in descending and thoracoabdominal aortic repair: a prospective multicenter observational study

PURPOSE

Cerebrospinal fluid drainage (CSFD) is recommended during open or endovascular thoracic aortic repair. However, the incidence of CSFD complications is still high. Recently, CSF pressure has been kept high to avoid complications, but the efficacy of CSFD at higher pressures has not been confirmed. We hypothesize that CSFD at higher pressures is effective for preventing motor deficits.

METHODS

This prospective observational study included 14 hospitals that are members of the Japanese Society of Cardiovascular Anesthesiologists. Patients who underwent thoracic and thoracoabdominal aortic repair were divided into four groups: Group 1, CSF pressure around 10 mmHg; Group 2, CSF pressure around 15 mmHg; Group 3, CSFD initiated when motor evoked potential amplitudes decreased; and Group 4, no CSFD. We assessed the association between the CSFD group and motor deficits using mixed-effects logistic regression with a random intercept for the institution.

RESULTS

Of 1072 patients in the study, 84 patients (open surgery, 51; thoracic endovascular aortic repair, 33) had motor deficits at discharge. Groups 1 and 2 were not associated with motor deficits (Group 1, odds ratio (OR): 1.53, 95% confidence interval (95% CI): 0.71-3.29, p = 0.276; Group 2, OR: 1.73, 95% CI: 0.62-4.82) when compared with Group 4. Group 3 was significantly more prone to motor deficits than Group 4 (OR: 2.56, 95% CI: 1.27-5.17, p = 0.009).

CONCLUSION

CSFD is not associated with motor deficits in thoracic and thoracoabdominal aortic repair with CSF pressure around 10 or 15 mmHg.

Open Treatments for Thoracoabdominal Aortic Aneurysm Repair

Thoracoabdominal aortic aneurysms (TAAA) represent a unique pathology that is associated with considerable mortality if untreated. While the advent of endovascular technologies has introduced new modalities for consideration, the mainstay of TAAA treatment remains open surgical repair. However, the optimal conduct of open TAAA repair requires careful consideration of patient risk factors and a collaborative team effort to mitigate the risk of perioperative complications. In this chapter, we briefly outline the history of treating TAAA, preoperative preparation and postoperative care, and our operative techniques for treatment.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate. Structure: Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

Cerebrospinal Fluid Drainage for Prevention of Spinal Cord Ischemia in Thoracic Endovascular Aortic Surgery-Pros and Cons

Thoracic endovascular aortic repair (TEVAR) carries a risk of spinal cord ischemia (SCI) which exerts a devastating impact on patient's quality of life and life expectancy. Although routine prophylactic cerebrospinal fluid (CSF) drainage is not unequivocally supported by current data, several studies have demonstrated favorable outcomes. Patients at high risk for SCI following TEVAR likely will benefit from prophylactic CSF drains. However, the intervention is not risk free, and thorough risk/benefit analysis should be individualized to each patient.

Our experience with 1000 recent thoracoabdominal aneurysm repairs, including endovascular stenting

OBJECTIVE

Managing patients with thoracoabdominal aneurysms is demanding yet fascinating, and requires a team effort. This invited talk presents lessons learned as our history with open and endovascular procedures evolved for 2578 descending and thoracoabdominal repairs over the past 20 years.

METHODS

Beginning in 1985 with an analysis of 596 traumatic aortic ruptures and the risk of spinal cord ischemia, the evolution of research and procedures for thoracoabdominal aneurysms progressed. The focus of these studies, medication trials, and procedure adjustments was on lowering the risk of spinal cord ischemia.

RESULTS

Between January 2002 and December 2021, 2578 aneurysm repairs were performed. The respective mortality rates were 6.8% and 4.0% for all patients treated. The permanent spinal cord ischemia rates were 1.3% for open descending thoracic aortas and 4.9% for open thoracoabdominal aneurysms. A detailed analysis of open and thoracoabdominal repairs showed better long-term outcomes with open repairs.

CONCLUSIONS

Through multiple randomized trials and innovations with procedures and techniques, the risk of death and spinal cord ischemia have been reduced. Long-term survival has also been improved. The pursuit of reducing the risks of descending and ascending thoracoabdominal repairs is a fascinating endeavor that has resulted in better patient outcomes. Nevertheless, this is a journey, and there will always be more room to achieve even better results.

Systematic review and meta-analysis of association of prophylactic cerebrospinal fluid drainage in preventing spinal cord ischemia after thoracic endovascular aortic repair

OBJECTIVE

We conducted a systemic review and meta-analysis to compare the association between prophylactic cerebrospinal fluid drainage (CSFD) vs non-CSFD in preventing spinal cord ischemia (SCI) after thoracic endovascular aortic repair (TEVAR) for aneurysm and dissection.

METHODS

The MEDLINE, Embase, and Cochrane databases were systematically searched to identify all relevant studies reported before April 1, 2020. A systematic review and meta-analysis were performed. We assessed the association between CSFD strategies, including routine CSFD vs selective CSFD or no CSFD, and the SCI rates after TEVAR for patients with aortic dissection (AD), solitary thoracic aortic aneurysm (TAA), or thoracoabdominal aortic aneurysm (TAAA). Subgroup analyses were conducted to assess the association between different aortic pathologies, including AD and thoracic aneurysms, and SCI rates after TEVAR with and without prophylactic CSFD. The data are presented as the pooled event rates (ERs) and 95% confidence intervals (CIs).

RESULTS

A total of 34 studies of 3561 patients (2671 with TAA or TAAA and 890 with type B AD) were included in the present analysis. The data are presented as the pooled ERs and 95% CIs. The overall SCI rate for patients who had undergone TEVAR with prophylactic CSFD for AD (ER, 1.80%; 95% CI, 0.88%-2.72%) was significantly lower than that for the aortic aneurysm group (ER, 5.73%; 95% CI, 4.20%-7.27%; P < .0001). The SCI rate after TEVAR with prophylactic CSFD was not significantly different from that without CSFD for AD (P = .51). No association was found between the rates of SCI after TEVAR with routine prophylactic CSFD vs selective prophylactic CSFD for aortic aneurysms (P = .76) and AD (P = .70). The SCI rate after TEVAR without CSFD for aortic aneurysms, including isolated TAA and TAAA (ER, 3.49%; 95% CI, 0.23%-6.76%) was not significantly different from that for AD (ER, 3.20%; 95% CI, 0.00%-7.20%; P = .91). For the patients with TAAAs, the rate of SCI after TEVAR with routine prophylactic CSFD was significantly lower than that with selective prophylactic CSFD (P = .04).

CONCLUSIONS

Our systematic review and meta-analysis has shown that SCI occurs more often after TEVAR for aortic aneurysms than for AD. Routine prophylactic CSFD, compared with selective CSFD, was associated with a lower rate of postoperative SCI after TEVAR for TAAAs. No significant association was found between the SCI rate and routine prophylactic CSFD for patients undergoing TEVAR for isolated TAA or AD.

Selective Versus Routine Spinal Drain Use for Fenestrated/Branched Endovascular Aortic Repair (F-BEVAR)

BACKGROUND

Spinal drains are used to ameliorate spinal cord ischemia (SCI), but their use may result in inherent morbidity and mortality. Although prophylactic spinal drain has proven of benefit in open repairs, that is not the case for endovascular repairs. The aim of this study was to assess the outcomes of spinal cord protection with and without the routine use of spinal drains during fenestrated-branched endovascular repair (F-BEVAR).

METHODS

A retrospective single center study was performed using a prospectively maintained dataset of all patients undergoing F-BEVAR over a 4-year period. The primary endpoint of the study was the frequency of SCI. Prophylactic spinal drain was placed pre-operatively in 33 patients (23%) with a median time for removal of 3 days (IQR, 2-3 days). Routine intraoperative neuromonitoring was used. Spinal cord protection relied primarily on maintaining a perioperative systolic blood pressure between 140 and 160 mm Hg or a mean arterial pressure >90 mm Hg, avoiding hypotension, preservation of as many collateral beds as possible, staged repairs and early lower extremity reperfusion based on neuromonitoring.

RESULTS

A total of 145 patients, 104 men (71%) and 41 women (28%) with a median age of 70 years (interquartile range [IQR], 53-62) underwent F-BEVAR. Branched custom-made devices (CMDs) (11%), fenestrated CMDs (70%) and off-the-shelf T-Branch device (17%) were used with a median number of branches/fenestrations of 4 (IQR, 3-4). SVS classification of implantation zones were determined as follows: 9 (6%) zone 2, 21 (20%) zone 3, 26 (18%) zone 4 and 89 (61%) zone 5. SCI was present in 8 patients (5.5%) and classified according to the SVS SCI grading system as follows: 1 grade 1, 5 grade 2 and 2 grade 3a. When evaluating implantation zone independently of coverage length and patency of collateral beds, a high implantation zone (1-4) was not associated with SCI (P = 0.9). Similarly, prophylactic spinal drain did not demonstrate association with the occurrence of SCI (3[9%] vs. 5[4%], with and without spinal drain, respectively) (P = 0.3). For patients with high implantation zones, staged repair was performed in 38 patients (26%) at a median time of 2 months (IQR, 2-6 months). Among these patients, the frequency of SCI was 13%. Staged repair was associated with an 80% reduction in the frequency of SCI (OR, 0.19 [95% CI, 0.04-0.084]) (P = 0.02).

CONCLUSION

F-BEVAR can be performed with a minimal risk of SCI without the need for routine prophylactic spinal drains. High implantation zones did not predict SCI after F-BEVAR; however, staged repair significantly decreased the risk of SCI after F-BEVAR.

Midterm Outcomes of a Prospective, Nonrandomized Study to Evaluate Endovascular Repair of Complex Aortic Aneurysms Using Fenestrated-Branched Endografts

OBJECTIVE

The aim of this study was to investigate the midterm outcomes of fenestrated and branched endovascular aortic repair (FB-EVAR) of pararenal (PRA) and thoracoabdominal aortic aneurysms (TAAAs).

SUMMARY BACKGROUND DATA

FB-EVAR has been associated with decreased morbidity compared to open repair, but there is limited midterm data.

METHODS

A total of 430 patients (302 males, mean age 74 ± 8 years) treated by FB-EVAR were enrolled in a prospective, nonrandomized investigational device exemption study. Endpoints included 30-day mortality and major adverse events (MAEs), freedom from all cause and aortic-related mortality, target vessel patency, and freedom from secondary intervention and target vessel instability.

RESULTS

There were 133 PRAs and 297 TAAAs with 1673 renal-mesenteric arteries incorporated by fenestrations or directional branches (3.9 ± 0.5 vessels/patient). At 30 days or within the hospital stay if longer than 30 days, there were 4 (0.9%) deaths. MAEs included new-onset dialysis in 8 patients (2%), permanent paraplegia or stroke in 10 patients each (2%), and respiratory failure requiring tracheostomy in 2 patients (0.5%). After a mean follow-up of 26 ± 20 months, there were 3 (0.7%) aortic-related deaths from SMA stent occlusion, gastrointestinal hemorrhage, or complications of open arch repair. At 5 years, freedom from all-cause and aortic-related mortality were 57% ± 5% and 98% ± 1%, respectively. Freedom from secondary intervention was 64% ± 4%, primary target vessel patency was 94% ± 1%, and freedom from target vessel instability was 89% ± 2% at same interval. One patient (0.2%) had nonfatal aneurysm treated using endovascular repair.

CONCLUSION

FB-EVAR is safe and effective for treatment of PRA and TAAAs with low rate of aortic-related mortality and aneurysm rupture on midterm follow-up.

The Evolution and Future of Spinal Drain for Thoracic Aortic Aneurysm Repair: A Review

For decades, spinal drains for cerebrospinal fluid (CSF) pressure monitoring and drainage have been used as adjuncts to protect against spinal cord injury resulting from thoracic aortic aneurysm repair. There are many different approaches to placement and management of CSF drains, with no true consensus on best practice. Furthermore, the incidence of complications resulting from spinal drains largely has been stagnant. This review describes the history and rationale behind placement of CSF drains, explore various considerations, techniques, and equipment, and discuss potential considerations for developing more comprehensive protocols.

Spinal drainage complications after aortic surgery

OBJECTIVE/BACKGROUND

Spinal drain (SD) placement is an adjunct used in open and endovascular aortic surgery to mitigate the risk of spinal cord injury. SD placement can lead to subdural hematoma and intracranial hemorrhage (SDH/ICH). Previous studies have highlighted a correlation between incidence of SDH/ICH and amount of cerebrospinal fluid (CSF) drained. We have two philosophies of SD management in our institution. One protocol allows fluid removal for pressure >10 cm H₂O with no volume restriction. A second, similar protocol restricts CSF drainage to <25 mL/h. We examined SD complications and the influence of volume restriction.

METHODS

Patients were identified according to the Current Procedure Terminology codes for SD placement, thoracic endovascular aortic repair, fenestrated/branched endovascular aortic repair, endovascular abdominal aortic repair, and open thoracic or thoracoabdominal aortic repair between January 1, 2012, and December 31, 2015. Patients' demographics included age, gender, race, body mass index, and comorbidities such as hypertension, chronic obstructive pulmonary disease, stroke, transient ischemic attack, diabetes mellitus, bleeding disorder, and connective tissue disorders. Management protocol was classified as volume independent (VI) or volume dependent (VD) by physician order. Postoperative complications related to the SD were noted.

RESULTS

We identified 948 patients who had an SD placed during the study period; 473 were done before aortic surgeries. A total of 364 patients (77%) underwent endovascular aortic surgery. The mean age at the time of procedure was 67.2 years, and 66% of patients were male. Thirty-nine patients (8.3%) were noted to have connective tissue disorders. Bloody SD placement occurred in 14 patients (3.1%) requiring rescheduling of the operation. SDH/ICH occurred in 11 patients (2.3%), postoperative blood tinged SD output in 94 patients (19.9 %), and 22 patients (4.7 %) had a CSF leak after SD removal. The incidence of SDH/ICH was not affected by the management protocol (2.6% VI vs 2.0% VD, P = .66), whereas the incidence of postoperative blood tinged SD output was significantly higher in the VI group (25.1% VI vs 15.0% VD, P = .006). Perioperative low-dose aspirin (81 mg) and prophylactic subcutaneous heparin did not increase the incidence of SDH/ICH. Postoperative thrombocytopenia was found to be associated with higher incidence of SDH/ICH (median 86,000 vs 113,000, P = .002).

CONCLUSIONS

Severe complications of SD placement (SDH/ICH) occur in 2.3% of SD patients undergoing aortic surgery, and the risk is higher in the setting of postoperative thrombocytopenia. SD volume limitation, blood tinged drainage, antiplatelet medication, and low-dose heparin do not affect the risk of SDH/ICH. The risks of spinal drains for aortic surgery should be balanced against potential benefits.

Trigger and Target for Fibrinogen Supplementation Using Thromboelastometry (ROTEM) in Patients Undergoing Open Thoraco-Abdominal Aortic Aneurysm Repair

OBJECTIVE

To determine the relationship between the value of fibrinogen assessed by the FIBTEM clot amplitude at 10 minutes (A10 FIBTEM) measured on admission to the intensive care unit (ICU) and the amount of drainage output at 24 hours, to investigate whether the A10 FIBTEM predicts severe bleeding (SB), and to define A10 FIBTEM thresholds to prevent (trigger) and treat (target) severe bleeding by fibrinogen supplementation.

METHODS

In a single centre, retrospective observational study, 166 patients underwent elective open thoraco-abdominal aortic aneurysm (TAAA) repair between March 2016 and January 2019. Exclusion criteria were emergency, congenital, or acquired coagulopathy, or administration of P₂Y₁₂ inhibitor antiplatelet agents in the five days before surgery. All patients were managed intra-operatively and post-operatively according to a rotational thromboelastometry driven transfusion protocol. The principal endpoint was a composite outcome, which included bleeding, large volume transfusion, and re-operation.

RESULTS

FIBTEM clot amplitude after 10 minutes measured on ICU admission and post-operative bleeding at 24 hours showed an inverse linear relationship (R² = .03; p = .026). Performance of A10 FIBTEM in predicting SB evaluated by Receiving Operating Curve analysis showed an area under the curve of 0.63 (95% CI 0.56 - 0.70; p = .026) with a best cutoff of 9 mm. An A10 FIBTEM of 3 mm was the cutoff associated with a positive predictive value of 50%, while an A10 FIBTEM of 9 mm showed a negative predictive value of 92%. On multivariable analysis, an A10 FIBTEM ≤ 3 mm remained independently associated with SB.

CONCLUSION

The present investigation shows for the first time in a population undergoing open TAAA repair that an A10 FIBTEM ≤ 3mm on ICU admission is associated with post-operative severe bleeding. Trigger and target values for fibrinogen supplementation, based on A10 FIBTEM, have been provided. The transferability and reliability of these cutoff values require further study.

Spinal cord protection in thoracoabdominal aortic aneurysm surgery: a multimodal approach

Spinal cord injury (SCI) is one major complication of open and endovascular thoracic and thoracoabdominal aortic aneurysm repair. Despite numerous neuroprotective adjuncts, the incidence of SCI remains high. This review article discusses established and novel adjuncts for spinal cord protection, including priming and preconditioning of the paraspinal collateral network, intraoperative systemic hypothermia, distal aortic perfusion, motor- and somatosensory evoked potentials and noninvasive cnNIRS monitoring as well as peri- and postoperative drainage of cerebrospinal fluid. Regardless of the positive influence of many of these strategies on neurologic outcome, to date no strategy assures definitive preservation of spinal cord integrity during and after aortic aneurysm repair.

Cerebrospinal fluid drainage to prevent postoperative spinal cord injury in thoracic aortic repair

BACKGROUND

Cerebrospinal fluid drainage (CSFD) is recommended as a spinal cord protective strategy in open and endovascular thoracic aortic repair. Although small studies support the use of CSFD, systematic reviews have not suggested definite conclusion and a large-scale study is needed. Therefore, we reviewed medical records of patients who had undergone descending and thoracoabdominal aortic repair (both open and endovascular repair) at multiple institutions to assess the association between CSFD and postoperative motor deficits.

METHODS

Patients included in this study underwent descending or thoracoabdominal aortic repair between 2000 and 2013 at 12 hospitals belonging to the Japanese Association of Spinal Cord Protection in Aortic Surgery. We conducted a retrospective study to investigate whether motor-evoked potential monitoring is effective in reducing motor deficits in thoracic aortic aneurysm repair. We use the same dataset to examine whether CSFD reduces motor deficits after propensity score matching.

RESULTS

We reviewed data from 1214 patients [open surgery, 601 (49.5%); endovascular repair, 613 (50.5%)]. CSFD was performed in 417 patients and not performed in the remaining 797 patients. Postoperative motor deficits were observed in 75 (6.2%) patients at discharge. After propensity score matching (n = 700), mixed-effects logistic regression performed revealed that CSFD is associated with postoperative motor deficits at discharge [adjusted odds ratio (OR), 3.87; 95% confidence interval (CI), 2.30-6.51].

CONCLUSION

CSFD may not be effective for postoperative motor deficits at discharge.

Spinal cord injury after open and endovascular repair of descending thoracic and thoracoabdominal aortic aneurysms: A meta-analysis

OBJECTIVE

An inclusive contemporary analysis of spinal cord injury (SCI) rates in patients undergoing aneurysm repair and the factors associated with complications has not been performed.

METHODS

Following a systematic literature search, studies from 2008 to 2018 on repair of descending thoracic aneurysm (DTA) and thoracoabdominal aortic aneurysm (TAAA) were pooled in a meta-analysis performed using the generic inverse variance method. The primary outcome was permanent SCI. Secondary outcomes were temporary SCI, operative mortality, long-term mortality, postoperative stroke, and cerebrospinal fluid (CSF) drain-related complications.

RESULTS

One-hundred sixty-nine studies (22,634 patients) were included. The pooled rate of permanent SCI was 4.5% (95% confidence interval [CI], 3.8-5.4); 3.5% (95% CI, 1.8-6.7) for DTA and 7.6% (96% CI, 6.2-9.3) for TAAA repair (P for subgroups = .02), 5.7% (95% CI, 4.3-7.5) for open repair and 3.9% (95% CI, 3.1-4.8) for endovascular repair (P for subgroups = .03). Rates for Crawford extents I, II, III, IV, and V aneurysms were 4.0% (95% CI, 3.0-5.0), 15.0% (95% CI, 10.0-22.0), 7.0% (95% CI, 6.0-9.0), 2.0% (95% CI, 2.0-4.0), and 7.0% (95% CI, 2.0-23.0) respectively (P for subgroups <.001). The pooled rates for operative mortality, late mortality at a mean follow-up of 5.0 years, stroke, and temporary SCI were 7.4% (95% CI, 6.1-9.4), 1.0% (95% CI, 0.0-1.0), 4.2% (95% CI, 3.6-4.8), and 3.7% (95% CI, 3.0-4.6), respectively. The pooled rates for severe, moderate, and minor CSF-drain related complications were 5.1% (95% CI, 2.23-11.1), 4.1% (95% CI, 0.6-22.0), and 3.6% (95% CI, 1.2-8.0) respectively.

CONCLUSIONS

Despite improvement, both open and endovascular aneurysm repair remain associated with a substantial risk of permanent SCI. The risk is greater for TAAA repair, especially extent II, III, and V.

Acute Spinal Cord Injury: Monitoring Lumbar Cerebrospinal Fluid Provides Limited Information about the Injury Site

In some centers, monitoring lumbar cerebrospinal fluid (CSF) is used to guide management of patients with acute traumatic spinal cord injuries (TSCI) and draining lumbar CSF to improve spinal cord perfusion. Here, we investigate whether the lumbar CSF provides accurate information about the injury site and the effect of draining lumbar CSF on injury site perfusion. In 13 TSCI patients, we simultaneously monitored lumbar CSF pressure (CSFP) and intraspinal pressure (ISP) from the injury site. Using CSFP or ISP, we computed spinal cord perfusion pressure (SCPP), vascular pressure reactivity index (sPRx) and optimum SCPP (SCPP_opt). We also assessed the effect on ISP of draining 10 mL CSF. Metabolites at the injury site were compared with metabolites in the lumbar CSF. We found that ISP was pulsatile, but CSFP had low pulse pressure and was non-pulsatile 21% of the time. There was weak or no correlation between CSFP versus ISP (R = -0.11), SCPP_(csf) versus SCPP_(ISP) (R = 0.39), and sPRx_(csf) versus sPRx_(ISP) (R = 0.45). CSF drainage caused no significant change in ISP in 7/12 patients and a significant drop of <5 mm Hg in 4/12 patients and of ∼8 mm Hg in 1/12 patients. Metabolite concentrations in the CSF versus the injury site did not correlate for lactate (R = 0.00), pyruvate (R = -0.12) or lactate-to-pyruvate ratio (R = -0.05) with weak correlations noted for glucose (R = 0.31), glutamate (R = 0.61), and glycerol (R = 0.56). We conclude that, after a severe TSCI, monitoring from the lumbar CSF provides only limited information about the injury site and that lumbar CSF drainage does not effectively reduce ISP in most patients.

Spinal cord deficit after 1114 extent II open thoracoabdominal aortic aneurysm repairs

OBJECTIVE

Crawford extent II repairs are the most extensive thoracoabdominal aortic aneurysm operations and pose the greatest risk of postoperative spinal cord deficit. We sought to examine spinal cord deficit after open extent II thoracoabdominal aortic aneurysm repair to identify predictors of the most serious type: persistent paraplegia or paraparesis.

METHODS

We included 1114 extent II thoracoabdominal aortic aneurysm repairs performed from 1991 to 2017. Intercostal/lumbar artery reattachment (n = 959, 86.1%) and cerebrospinal fluid drainage (n = 698, 62.7%) were used to mitigate the risk of postoperative spinal cord deficit. We used univariate and multivariable analyses to examine spinal cord deficit and identify predictors of persistent paraplegia or paraparesis, defined as paraplegia or paraparesis present at the time of early death or hospital discharge.

RESULTS

Spinal cord deficit developed after 151 (13.6%) repairs: 86 (7.7%) cases of persistent paraplegia or paraparesis (51 paraplegia; 35 paraparesis) and 65 (6.1%) cases of transient paraplegia or paraparesis. Patients with spinal cord deficit were older (median 68 vs 65 years, P < .001) and had more rupture (6.6% vs 2.2%, P = .002) and urgent/emergency repair (25.2% vs 16.9%, P = .01) than those without. Persistent paraplegia or paraparesis developed immediately in 47 patients (4.2%) and was delayed in 39 patients (3.5%). Urgent/emergency repair (relative risk ratio, 2.31; P = .002), coronary artery disease (relative risk ratio, 1.80, P = .01), and chronic symptoms (relative risk ratio, 1.76, P = .02) independently predicted persistent paraplegia or paraparesis. Reattaching intercostal/lumbar arteries (relative risk ratio, 0.38, P < .001) and heritable disease (relative risk ratio, 0.36, P = .01) were protective. Early and late survival were poorer in those with persistent paraplegia or paraparesis than in those without.

CONCLUSIONS

Spinal cord deficit after extent II thoracoabdominal aortic aneurysm repairs remains concerning; survival is worse in patients with persistent paraplegia or paraparesis. The complexity of spinal cord deficit and persistent paraplegia or paraparesis warrant further study.

Cerebrospinal Fluid Drainage During Endovascular Aortic Aneurysm Repair: A Systematic Review of the Literature and Treatment Recommendations

Introduction:

Spinal cord injury (SCI) is a known complication of aortic aneurysm repair. Previous reports indicate that cerebrospinal fluid drainage (CSFD) may reduce incidence of SCI during open aortic aneurysm repair but its utility in endovascular repair remains poorly understood. We performed a systematic review of the literature to examine the protocols and outcomes of CSFD in patients undergoing endovascular aortic aneurysm repair.

Methods:

The Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were utilized to conduct a systematic literature review. PubMed, Scopus, Ovid, Cochrane, and EMBASE were queried for articles published since 2016 using search terms “(cerebrospinal fluid diversion OR CSF diversion OR lumbar drain OR subarachnoid drain OR spinal) AND (aortic aneurysm AND thoracic AND endovascular OR TEVAR).” Ninety-two articles were identified and screened by 2 independent reviewers, and 23 studies met criteria for full-text review after initial screening.

Results:

A total of 8 studies met full inclusion criteria for final analysis. Six studies reported incidence of SCI in patients with CSFD and 2 compared SCI incidence between patients with and without CSFD. Protocols for drainage most commonly included draining to a target pressure intra- and postoperatively, between 8 and 12 mm Hg. Incidence of SCI ranged from 0% to 17% in patients with CSFD, and from 0% to 50% in those without CSFD. Rates of CSFD-related complications ranged from <1% to 28%.

Conclusion:

There may be a protective benefit of CSFD in preventing SCI, but there remains significant variation in drain placement protocols. Significant potential bias exists in the reviewed data. Higher quality studies on the role of CSFD in endovascular aortic aneurysm repair are needed.

Thoracoabdominal Aortic Aneurysm Repair: From an Era of Revolution to an Era of Evolution

Thoracoabdominal aortic aneurysm (TAAA) repair has a rich and storied tradition that began in Houston, Texas with great pioneer surgeons such as Drs Michael E. DeBakey, Denton A. Cooley, and E. Stanley Crawford. Their early attempts to repair TAAA were complicated by the persistent threats of renal and spinal cord ischemia and difficulty in reattaching the branching vessels of the thoracoabdominal aorta. Today, under the tutelage of Dr Joseph S. Coselli, the Texas Medical Center remains at the forefront of TAAA repair. In this place where great surgeons once walked the halls, their legacy continues.

Cerebrospinal fluid drainage and thoracic endovascular aneurysm repair

Spinal cord complications including paraplegia and partial neurologic deficits remain a frequent problem during repair of descending thoracic or thoracoabdominal aortic aneurysms. Effective prevention of this dreaded complication is of paramount importance. Among the many adjuncts that have been proposed to prevent spinal cord complications, spinal fluid drainage is one that has been used by numerous teams. The aim of this review is to answer the following question: does spinal fluid drainage afford spinal cord protection during both open and endovascular repair of thoracic or thoracoabdominal aortic aneurysms?

Perioperative cerebrospinal fluid drainage for the prevention of spinal ischemia after endovascular aortic repair

Endovascular treatment of thoracic and thoracoabdominal aortic diseases is accompanied by a risk of spinal ischemia in 1-19% of patients, depending on the entity and extent of the disease. The use of perioperative drainage of cerebrospinal fluid is one of the invasive measures to reduce the occurrence of this severe complication. This article reviews the incidence of spinal ischemia, its risk factors, the evidence for carrying out cerebrospinal fluid drainage and its modern use by means of an automated, pressure controlled system (LiquoGuard®7).

The seven attributes of the academic surgeon: Critical aspects of the archetype and contributions to the surgical community

BACKGROUND

"Academic surgeon" describes a member of a medical school department of surgery, but this term does not fully define the important role of such physician-scientists in advancing surgical science through translational research and innovation.

METHODS

The curriculum vitae and self-descriptive vignettes of the records of achievement of seven surgeons possessing documented records of academic leadership, innovation, and dissemination of knowledge were reviewed.

RESULTS

Out analysis yielded seven attributes of the archetypal academic surgeon: 1) identifies complex clinical problems ignored or thought unsolvable by others, 2) becomes an expert, 3) innovates to advance treatment, 4) observes outcomes to further improve and innovate, 5) disseminates knowledge and expertise, 6) asks important questions to further improve care, and 7) trains the next generation of surgeons and scientists.

CONCLUSION

Although alternative pathways to innovation and academic contribution also exist, the academic surgeon typically devotes years of careful observation, analysis, and iterative investigation to identify and solve challenging or unexplored clinical problems, ideally leverages resources available in academic medical centers to support these endeavors.

Thoracoabdominal Aortic Aneurysm Repair: Reducing the Incidence of Paraplegia

Paraplegia is a major complication associated with repair of thoracoabdominal aortic aneurysms (TAAA). A number of therapies have been tried over the years, none of which has been successful. Recently, regional lumbar epidural cooling has been tried in an attempt to prolong the safe ischemic time during aortic cross- clamping. In approximately 90 patients in whom the authors have tried this technique, there was no de crease in the incidence of paraplegia in patients with type II TAAAs. This is perhaps not unanticipated be cause the paraplegia is related to a number of factors including the duration of the aortic cross-clamping, the adequacy of collateral circulation, embolization during the procedure, and perhaps thrombosis in situ. Given the multimodal cause of paraplegia, perhaps it is naive to think that a single therapy would be of benefit. Additional studies are necessary to explore the mecha nisms and to prove efficacy or lack of benefit of any techniques designed to decrease the incidence of paraplegia in patients undergoing TAAA repair.

Deep Hypothermia and Circulatory Arrest in Adults

Brain protection during cardiopulmonary bypass has been the subject of intense research. Deep hypothermic circulatory arrest (DHCA) continues to be used for that goal during complex aortic arch and large intracranial aneurysm surgeries. The anesthetic management for adult patients undergoing these types of procedures requires specific knowledge and expertise. Based on our experience and review of the current literature, the authors highlight the key areas of the anesthetic plan, discussing the risk factors associated with adverse neurologic outcome as well as the rationale for decisions regarding specific monitors and medications. In the conclusion an anesthetic protocol for adult patients undergoing DHCA is suggested.

Bypass Techniques for Descending Thoracic Aortic Surgery

The conduct of partial left heart bypass or partial car diopulmonary bypass (CPB) during surgery involving the descending thoracic aorta or thoracoabdominal aorta is one of the most unappreciated and misunder stood extracorporeal circulation procedures in cardio vascular surgery. It is different from conventional CPB, and although some uninitiated practitioners consider it simpler, it is in fact more complicated than conven tional CPB and involves different concepts. It requires expertise and skill in regulating the flow, pressure, and oxygenation of blood going to both the proximal and distal parts of the body and management of the special bypass or shunt procedures used, specialized monitor ing, and knowledge about the protection and preserva tion of organs both proximal and distal to the aortic clamping. It demands exquisite communication and un derstanding of the unique problems faced by the sur geon, anesthesiologist, and perfusionist.

Extent II Thoracoabdominal Aortic Aneurysm Repair: How I Do It

The primary risks associated with thoracoabdominal aortic aneurysm (TAAA) repair-namely operative death, paraplegia, and renal failure necessitating dialysis-are commonly related to the distal ischemia that occurs during aortic clamping and the disruption of vital branching arteries. Our technique for open TAAA repair has evolved over the course of 3 decades, from the unheparinized, simple "clamp-and-sew" approach learned directly from E. Stanley Crawford himself to a contemporary, multimodal strategy that uses an array of surgical adjuncts. Today, our approach to TAAA repair is largely standardized and based on the Crawford extents of TAAA repair, but we have maintained flexibility to explore new techniques and to adapt to the specific needs of patients. To protect the spinal cord, we routinely use mild passive hypothermia, cerebrospinal fluid drainage, left heart bypass, and reimplantation of crucial intercostal or lumbar arteries. The renal arteries are perfused with cold solution to protect the kidneys from ischemic damage, and the celiac axis and superior mesenteric artery are perfused with isothermic blood from the left heart bypass circuit, which minimizes the duration of abdominal-organ ischemia. The most extensive repair, Crawford extent II repair, typically replaces the aorta from just beyond the left subclavian artery to the aortic bifurcation; unsurprisingly, it commonly poses greater operative risk than do less extensive TAAA repairs (extent I, III, and IV). Subsequently, most surgical adjuncts used today were developed to ameliorate risk in extent II repair. Here, we provide a detailed description of our approach to open extent II TAAA repair.

Update in the management of type B aortic dissection

Stanford type B aortic dissection (TBAD) is a life-threatening aortic disease. The initial management goal is to prevent aortic rupture, propagation of the dissection, and symptoms by reducing the heart rate and blood pressure. Uncomplicated TBAD patients require prompt medical management to prevent aortic dilatation or rupture during subsequent follow-up. Complicated TBAD patients require immediate invasive management to prevent death or injury caused by rupture or malperfusion. Recent developments in diagnosis and management have reduced mortality related to TBAD considerably. In particular, the introduction of thoracic stent-grafts has shifted the management from surgical to endovascular repair, contributing to a fourfold increase in early survival in complicated TBAD. Furthermore, endovascular repair is now considered in some uncomplicated TBAD patients in addition to optimal medical therapy. For more challenging aortic dissection patients with involvement of the aortic arch, hybrid approaches, combining open and endovascular repair, have had promising results. Regardless of the chosen management strategy, strict antihypertensive control should be administered to all TBAD patients in addition to close imaging surveillance. Future developments in stent-graft design, medical therapy, surgical and hybrid techniques, imaging, and genetic screening may improve the outcomes of TBAD patients even further. We present a comprehensive review of the recommended management strategy based on current evidence in the literature.

The use of lumbar drains in preventing spinal cord injury following thoracoabdominal aortic aneurysm repair: an updated systematic review and meta-analysis

OBJECTIVE Paraplegia and paraparesis following aortic aneurysm repair occur at a substantially high rate and are often catastrophic to patients, their families, and the overall health care system. Spinal cord injury (SCI) following open thoracoabdominal aortic aneurysm (TAAA) repair is reported to be as high as 20% in historical controls. The goal of this study was to determine the impact of CSF drainage (CSFD) on SCI following TAAA repair. METHODS In August 2015 a systematic literature search was performed using clinicaltrials.gov , the Cochrane Library, PubMed/MEDLINE, and Scopus that identified 3478 articles. Of these articles, 10 met inclusion criteria. Random and fixed-effect meta-analyses were performed using both pooled and subset analyses based on study type. RESULTS The meta-analysis demonstrated that CSFD decreased SCI by nearly half (relative risk 0.42, 95% confidence interval 0.25-0.70; p = 0.0009) in the pooled analysis. This effect remained in the subgroup analysis of early SCI but did not remain significant in late SCI. CONCLUSIONS This meta-analysis showed that CSFD could be an effective strategy in preventing SCI following aortic aneurysm repair. Care should be taken to prevent complications related to overdrainage. No firm conclusions can be drawn about the newer endovascular procedures at the current time.

Predicting postoperative acute respiratory failure in critical care using nursing notes and physiological signals

Postoperative Acute Respiratory Failure (ARF) is a serious complication in critical care affecting patient morbidity and mortality. In this paper we investigate a novel approach to predicting ARF in critically ill patients. We study the use of two disparate sources of information – semi-structured text contained in nursing notes and investigative reports that are regularly recorded and the respiration rate, a physiological signal that is continuously monitored during a patient's ICU stay. Unlike previous works that retrospectively analyze complications, we exclude discharge summaries from our analysis envisaging a real time system that predicts ARF during the ICU stay. Our experiments, on more than 800 patient records from the MIMIC II database, demonstrate that text sources within the ICU contain strong signals for distinguishing between patients who are at risk for ARF from those who are not at risk. These results suggest that large scale systems using both structured and unstructured data recorded in critical care can be effectively used to predict complications, which in turn can lead to preemptive care with potentially improved outcomes, mortality rates and decreased length of stay and cost.

Intraoperative Changes in Cerebrospinal Fluid Gas Tensions Reflect Paraplegia During Thoracoabdominal Aortic Surgery

Background:

In this study, gas tensions in cerebrospinal fluid (CSF) were prospectively evaluated as intraoperative markers for the detection of neurological deficits.

Methods:

Spinal fluid, serum, and heart lung machine (HLM) perfusate were monitored for gas tensions (po2/pCo2) and related parameters (pH, lactate, and glucose) during thoracoabdominal aortic repair and correlated with perioperative neurological examination and electrophysiological testing.

Results:

Forty-seven patients were assessed for the study, and 40 consecutive patients were finally included. The patients were divided into 3 groups: group A (23 patients, 57.5%): no clinical or laboratory signs of neurological damage; group B (14 patients, 35%) who developed subclinical deficits; and group C (3 patients, 7.5%) who had paraplegia. Significant intraoperative changes in CSF gas tensions were observed with postoperative paraplegia. Glucose ratio between serum and CSF showed higher variability in group C, confirming a damage of the blood–brain barrier (BBB).

Conclusion:

Major neurological damage is reflected by early changes in CSF gas tensions and glucose variability, suggesting damage of the BBB in these patients.

Spinal cord injury following thoracic and thoracoabdominal aortic repairs

Objective

To discuss the currently available approaches to prevent spinal cord injury during thoracic and thoracoabdominal aortic repairs.

Methods

We carried out a PubMed search up to 2013 using the Medical Subject Headings: “aortic aneurysm/surgery” and “spinal cord ischemia”; “aortic aneurysm, thoracic/surgery” and “spinal cord ischemia”; “aneurysm/surgery” and “spinal cord ischemia/cerebrospinal fluid”; “aortic aneurysm/surgery” and “paraplegia”. All 190 original articles satisfying our inclusion criteria were analyzed for incidence, predictors, and other pertinent variables related to spinal cord injury, and we compared the results in recent publications with those in earlier reports.

Results

The mean age of the 38,491 patients was 65.3 ± 4.9 years. The overall incidence of paraplegia and/or paraparesis was 7.1% ± 6.1% (range 0%–32%). The incidence of spinal cord injury before 2000, from 2001 to 2007, and 2008–2013 was 9.0% ± 6.7%, 7.0% ± 6.1%, and 5.9% ± 5.2%, respectively ( p = 0.019). Various predictors of spinal cord injury were identified, extent of disease being the most common. Modification of surgical techniques, use of adjuncts, and better understanding of spinal cord perfusion physiology were attributed to the decrease in postoperative spinal cord injury in recent years.

Conclusions

Spinal cord injury after thoracic and thoracoabdominal aortic repair poses a real challenge to cardiovascular surgeons. However, with evolving surgical strategies, identification of predictors, and use of various adjuncts over the years, the incidence of spinal cord injury after thoracic/thoracoabdominal aortic repair has declined. Embracing a multimodality approach offers a good insight into combating this grave complication.