Predictors of morbidity and mortality with endovascular and open thoracic aneurysm repair

Machine Learning and Omics Analysis in Aortic Aneurysm

Aortic aneurysm is a life-threatening condition and mechanisms underlying its formation and progression are still incompletely understood. Omics approach has brought new insights to identify a broad spectrum of biomarkers and better understand cellular and molecular pathways involved. Omics generate a large amount of data and several studies have highlighted that artificial intelligence (AI) and techniques such as machine learning (ML)/deep learning (DL) can be of use in analyzing such complex datasets. However, only a few studies have so far reported the use of ML/DL for omics analysis in aortic aneurysms. The aim of this study is to summarize recent advances on the use of ML/DL for omics analysis to decipher aortic aneurysm pathophysiology and develop patient-tailored risk prediction models. In the light of current knowledge, we discuss current limits and highlight future directions in the field.

Impact of Female Sex on Outcomes of Patients Undergoing Thoracic Endovascular Aortic Aneurysm Repair: A Ten-Year Retrospective Nationwide Study in France

The impact of sex on the outcomes of patients with cardiovascular disease is still incompletely understood. The aim of this nationwide multicenter observational study was to investigate the impact of sex on post-operative outcomes in patients undergoing thoracic endovascular aortic repair (TEVAR) for intact thoracic aortic aneurysm (iTAA). The French National Health Insurance Information System was searched to identify these patients over a ten-year retrospective period. Post-operative outcomes, 30-day and overall mortality were recorded. Among the 7383 patients included (5521 men and 1862 women), females were significantly older than males (66.8 vs. 64.8 years, p < 0.001). They were less frequently diagnosed with cardiovascular comorbidities. Post-operatively, women had less frequently respiratory (10.9 vs. 13.7%, p = 0.002) as well as cardiac complications (34.3 vs. 37.3%, p = 0.023), but they had more frequently arterial complications (52.8 vs. 49.8%, p = 0.024). There was no significant difference on overall mortality for a mean follow-up of 2.2 years (26.9 vs. 27.6%, p = 0.58). In the multivariable regression model, female sex was not associated with 30-day or overall mortality. Although women had a favorable comorbidity profile, the short-term and long-term survival was similar. The significantly higher rate of arterial complications suggests that women may be at higher risk of access-vessel-related complications.

Systematic review of endovascular stent grafting versus open surgical repair for the elective treatment of arch/descending thoracic aortic aneurysms

OBJECTIVE

To review comparisons of the effectiveness of endovascular stent grafting (ESG) against open surgical repair (OSR) for treatment of chronic arch or descending thoracic aortic aneurysms (TAA).

DESIGN

Systematic review and meta-analysis DATA SOURCES: MEDLINE, EMBASE, CENTRAL, WHO International Clinical Trials Routine data collection, current controlled trials, clinical trials and the NIHR portfolio were searched from January 1994 to March 2020.

ELIGIBILITY CRITERIA FOR SELECTIVE STUDIES

All identified studies that compared ESG and OSR, including randomised controlled trials (RCTs), quasi-randomised and non-RCTs, comparative cohort studies and case-control studies matched on main outcomes were sought. Participants had to receive elective treatments for arch/descending (TAA). Studies were excluded where other thoracic aortic conditions (eg, rupture or dissection) were reported, unless results for patients receiving elective treatment for arch/descending TAA reported separately.

DATA EXTRACTION AND SYNTHESIS

Data were extracted by one reviewer and checked by another. Risk of Bias was assessed using the ROBINS-I tool. Meta-analysis was conducted using random effects. Where meta-analysis not appropriate, results were reported narratively.

RESULTS

Five comparative cohort studies met inclusion criteria, reporting 3955 ESG and 21 197 OSR patients. Meta-analysis of unadjusted short-term (30 day) all-cause mortality favoured ESG (OR 0.75; 95% CI 0.55 to 1.03)). Heterogeneity identified between larger and smaller studies. Sensitivity analysis of four studies including only descending TAA showed no statistical significance (OR 0.73, 95% CI 0.45 to 1.18)), moderate heterogeneity. Meta-analysis of adjusted short-term all-cause mortality favoured ESG (OR 0.71, 95% CI 0.51 to 0.98)), no heterogeneity. Longer-term (beyond 30 days) survival from all-cause mortality favoured OSR in larger studies and ESG in smaller studies. Freedom from reintervention in the longer-term favoured OSR. Studies reporting short-term non-fatal complications suggest fewer events following ESG.

CONCLUSIONS

There is limited and increasingly dated evidence on the comparison of ESG and OSR for treatment of arch/descending TAA.

PROSPERO REGISTRATION NUMBER

CRD42017054565.

New Preoperative Spinal Cord Ischemia Risk Stratification Model for Patients Undergoing Thoracic Endovascular Aortic Repair

PURPOSE

Our objective was to determine significant predictors of spinal cord ischemia (SCI) following Thoracic Endovascular Aortic Repair (TEVAR) and to further develop a simple and clinically orientated risk score model.

METHODS

A retrospective review of data from the Society of Vascular Surgery/Vascular Quality Initiative national data set was performed for all patients undergoing TEVAR from January, 2014 to June 2018. Preoperative demographics, procedure-related variables, and clinical details related to SCI were examined. A SCI risk score was developed utilizing a multivariable logistic regression model.

RESULTS

For the 7889 patients in the final analysis who underwent TEVAR during the study period, the mean age was 67.6 ± 13.9, range 18 to 90 years, and the majority was male (65%). Postoperative outcomes included stroke (3.0%), myocardial infarction (2.9%), inhospital mortality (5.4%), transient SCI (1.5%), and permanent SCI (2.1%). Nearly half of the overall cases were performed in high volume centers. Predictors of increased risk for SCI included age by decade (odds ratio [OR]: 1.2), celiac coverage (OR: 1.5), current smoker (OR: 1.6), dialysis (OR: 1.9), 3 or more aortic implanted devices (OR: 1.7), emergent or urgent surgery (OR: 1.5), adjunct aorta-related procedure (OR: 2.5), adjunct not related (OR: 2.6), total estimated length of aortic device (19-31 cm, OR: 1.9 and ≥32 cm, OR: 3.0), ASA class 4 or 5 (OR: 1.6), and procedure time ≥154 minutes (OR: 1.8). Two predictors decreased the risk of SCI, cases from high-volume centers (OR: 0.6) and eGFR ≥ 60 (OR: 0.6). To evaluate the risk score model, probabilities of SCI from the original regression, raw score, and raw score categories resulted in area under the curve statistics of 0.792, 0.786, and 0.738, respectively.

CONCLUSIONS

Spinal cord ischemia remains one of the most feared complications of TEVAR. Incidence of SCI in this large series of patients with TEVAR was 3.6% with nearly 60% being permanent. The proposed model provides an assessment tool to guide clinical decisions, patient consent process, risk-assessment, and procedural strategy.

CNB-001 reduces paraplegia in rabbits following spinal cord ischemia

Spinal cord ischemia associated with trauma and surgical procedures including thoraco-abdominal aortic aneurysm repair and thoracic endovascular aortic repair results in devastating clinical deficits in patients. Because spinal cord ischemia is inadequately treated, we studied the effects of [4-((1E)-2-(5-(4-hydroxy-3-methoxystyryl-)-1-phenyl-1H-pyrazoyl-3-yl) vinyl)-2-methoxy-phenol)] (CNB-001), a novel curcumin-based compound, in a rabbit SCI model. CNB-001 is known to inhibit human 5-lipoxygenase and 15-lipoxygenase and reduce the ischemia-induced inflammatory response. Moreover, CNB-001 can reduce the level of oxidative stress markers and potentiate brain-derived neurotrophic factor and brain-derived neurotrophic factor receptor signaling. The Tarlov scale and quantal analysis technique results revealed that CNB-001 administered as an intravenous dose (bolus) 30 minutes prior to spinal cord ischemia improved the behaviors of female New Zealand White rabbits. The improvements were similar to those produced by the uncompetitive N-methyl-D-aspartate receptor antagonist memantine. At 48 hours after aortic occlusion, there was a 42.7% increase (P < 0.05) in tolerated ischemia duration (n = 14) for rabbits treated with CNB-001 (n = 16), and a 72.3% increase for rabbits treated with the positive control memantine (P < 0.05) (n = 23) compared to vehicle-treated ischemic rabbits (n = 22). CNB-001 is a potential important novel treatment for spinal cord ischemia induced by aortic occlusion. All experiments were approved by the CSMC Institutional Animal Care and Use Committee (IACUC #4311) on November 1, 2012.

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?

Novel Risk Score Model for Prediction of Survival Following Elective Endovascular Abdominal Aortic Aneurysm Repair

OBJECTIVE

The purpose of this study was to identify significant predictors of long-term mortality after elective endovascular abdominal aortic aneurysm repair (EVAR).

METHODS

We included all cases with elective EVAR based on a national data set from the Society for Vascular Surgery Patient Safety Organization. Clinical and anatomic variables were analyzed with a Kaplan-Meier and Cox-regression model to determine predictors of mortality and develop a score equation to categorize patients into low, medium, and high long-term mortality risk.

RESULTS

A total of 5678 patients with EVAR were included with an average age of 73.6 ± 8.2 years. The majority were male (81.6%) with a history of smoking (86.1%). There were 3 deaths within 30 days (0.1%). Several factors were associated with poor survival: unstable angina (hazard ratio [HR], 2.8; P = .008), dialysis (HR, 3.7; P < .001), estimated glomerular filtration rate (eGFR) <30 (HR, 1.7; P = .044), eGFR 30 to 59 (HR, 1.4; P = .002), age >80 (HR, 3.2; P < .001), age 75 to 79 (HR, 2.2; P < .001), chronic obstructive pulmonary disease on oxygen (HR, 3.3; P < .001), aortic diameter >5.8 cm (HR, 1.2; P = .043), and high risk for surgery (HR, 1.4; P = .043). Preoperative aspirin use and body mass index 25 to 35 were both found to be protective (HR, 0.78; P = .017 and HR, 0.8; P = .024, respectively). With our scoring model, 5- and 10-year survival rates for patients with low, medium, and high risk were 89.2%, 80.7%, and 64.1% and 77.2%, 60.1%, and 40.1%, respectively (P < .001).

CONCLUSION

Ten-year survival following EVAR in patients with a high-risk score utilizing the model provided was 40.1%. Patients with multiple comorbidities at risk for decreased long-term survival can be identified with our model, which is more applicable for high-volume contemporary institutions.

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.

Treatment decisions for descending thoracic aneurysm: preferences for thoracic endovascular aneurysm repair or surveillance in a discrete choice experiment

OBJECTIVE

To investigate and rank factors that influence endovascular treatment decisions by specialists for patients with descending thoracic aortic aneurysm (dTAA).

METHODS

Specialists completed a diagrammatic survey describing uncertainty about the benefit of thoracic endovascular aneurysm repair (TEVAR) for dTAA with respect to age, sex, and aneurysm diameter. Subsequently, a detailed discrete choice experiment was designed. Specialists were recruited and asked to indicate treatment their preference (TEVAR or surveillance) in 25 hypothetical cases of dTAA, with variable patient attributes: age, sex, American Society of Anesthesiologists (ASA) grade, aneurysm diameter, adequate landing zone distal to left subclavian artery (LSA), and length of aortic coverage. Data were analysed using multiple logistic regression.

RESULTS

The diagrammatic survey, based on 50 respondents, showed that uncertainty about the benefits of TEVAR was greatest for patients aged 80-85 years (up to 47% of respondents were "unsure") and that uncertainty increased with increasing aneurysm diameter (for an 80-year-old man, 7% were unsure at 5.5 cm and 33% were unsure at 7.0 cm). Seventy-one specialists (mainly from Europe and North America, 86% vascular surgeons and 98% working in units offering TEVAR) completed the discrete choice experiment. Preference for TEVAR increased greatly with enlarging diameter: adjusted odds ratios (OR) >5.5-6.0 cm = 15.8 (95% confidence interval [CI] 9.83-25.40); >6.0-6.5 cm = 393.0 (95% CI 202.00-766.00); >6.5-7.0 cm = 1829.0 (95% CI 400.00-4,181.00). TEVAR was less likely to be preferred in patients older than 75 years (>75-80 years OR 0.32, 95% CI 0.21-0.49; >80-85 years = 0.18, 95% CI 0.11-0.28); in women (OR 0.52, 95% CI 0.37-0.74); in patients classified as ASA grade 4 (OR 0.44, 95% CI 0.36-0.57); and in patients with aorta coverage >25 cm (OR 0.48, 95% CI 0.32-0.74). The proximal landing zone did not influence preference.

CONCLUSION

Specialists' preferences for endovascular repair of degenerative dTAA vary widely, and demonstrate clinical uncertainty, especially in octogenarians, and a reluctance to offer TEVAR to women. Aneurysm diameter dominates treatment preferences, but patient fitness and length of aortic coverage (>25 cm) also were influential, although the landing zone distal to LSA was not.

Diseases of the thoracic aorta in women

Women have now equaled or surpassed men in the number of cardiovascular deaths per year in published statistics. In 2006, according to the National Center for Health Statistics and the Center for Disease Control, cardiovascular disease was the cause of death in 428,906 women (35% of all deaths in women) and in 394,840 men (33% of all deaths in men). Of those numbers, it was estimated that 5506 women (0.4% of all deaths in women) and 7732 men (0.6%) died because of aortic aneurysm or dissection. Currently, aortic disease ranks as the 19th leading cause of death with reported increases in incidence. Historically, aortic disease is thought to affect men more frequently than women with a varying reported gender ratio. Gender bias has long been implicated as an important factor, but often overlooked, in the analysis and interpretation of cardiovascular diseases outcome, in part, because of the under-representation of women in clinical trials and studies. In this section, we provide an up-to-date review of the epidemiology and management of common diseases of the thoracic aorta, focusing on the differences and similarities in women and men.

Predictors and outcomes of acute kidney injury after thoracic aortic endograft repair

BACKGROUND

This study analyzed the incidence and the predictive factors of postoperative acute kidney injury (AKI) after thoracic endovascular aortic repair (TEVAR) and evaluated the effect of AKI on postoperative survival.

METHODS

Between November 2000 and April 2011, all consecutive patients undergoing TEVAR of the descending thoracic or thoracoabdominal aorta were enrolled at four teaching hospitals. Estimated glomerular filtration rate (eGFR) was evaluated during the entire hospitalization. AKI was defined by the RIFLE (Risk, Injury, Failure, Loss of function, End-stage renal disease) consensus criteria.

RESULTS

The study included 171 patients (80% men) who were a mean age of 69±14 years (range, 18-87 years). AKI occurred in 24 patients (14%). Independent predictors of postoperative AKI were preoperative depressed eGFR, thoracoabdominal extent, and postoperative transfusion. Patients with AKI experienced major postoperative complications (P=.001), longer hospitalization (P=.008), and higher hospital mortality (29% vs 4%; P<.001). Kaplan-Meier analysis showed a survival of 82%, 51%, and 51% at 1, 3, and 5 years for patients who developed AKI, which was significantly worse than the 99%, 89%, and 80% for patients who did not experience AKI (P=.001).

CONCLUSIONS

Preoperative poor renal function, blood transfusions, and the thoracoabdominal extent of the aortic disease were the most important predictors for AKI.

Preoperative prediction of mortality within 1 year after elective thoracic endovascular aortic aneurysm repair

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) is known to have a survival benefit over open repair in patients with descending thoracic aneurysms and has become a mainstay of therapy. Because death before 1 year after TEVAR likely indicates an ineffective therapy, we have created a predictive model for death within 1 year using factors available in the preoperative setting.

METHODS

A registry of 526 TEVARs performed at the University of Florida between September 2000 and November 2010 was queried for patients with degenerative descending thoracic aneurysm as their primary pathology. Procedures with emergent or urgent indications were excluded. Preoperatively available variables, such as baseline comorbidities, anatomic-, and procedure-specific planning details, were recorded. Univariate predictors of death were analyzed with multivariable Cox proportional hazards to identify independent predictors of 30-day (death within 30 days) and 1-year mortality (death within 1 year) after TEVAR.

RESULTS

A total of 224 patients were identified and evaluated. The 30-day mortality rate was 3% (n = 7) and the 1-year mortality rate was 15% (n = 33). Multivariable predictors of 1-year mortality (hazard ratios [95% confidence interval]) included: age >70 years (5.8 [2.1-16.0]; P = .001), adjunctive intraoperative procedures (eg, brachiocephalic or visceral stents, or both, concomitant arch debranching procedures; 4.5 [1.9-10.8]; P = .001), peripheral arterial disease (3.0 [1.4-6.7]; P = .006), coronary artery disease (2.4 [1.1-4.9]; P = .02), and chronic obstructive pulmonary disease (1.9 [1.0-3.9]; P = .06). A diagnosis of hyperlipidemia was protective (0.4 [0.2-0.7]; P = .006). When patients were grouped into those with one, two, three, or four or more of these risk factors, the predicted 1-year mortality was 1%, 3%, 10%, 27%, and 54%, respectively.

CONCLUSIONS

Factors are available in the preoperative setting that are predictive of death within 1 year after TEVAR and can guide clinical decision making regarding the timing of repair. Patients with multiple risk factors, such as age ≥ 70 years, coronary artery disease, chronic obstructive pulmonary disease, and a need for an extensive procedure involving adjunctive therapies, have a high predicted mortality within 1 year and may be best served by waiting for a larger aneurysm size to justify the risk of intervention.

Risk factors for 1-year mortality after thoracic endovascular aortic repair

OBJECTIVE

Thoracic endovascular aortic repair, although physiologically well tolerated, may fail to confer significant survival benefit in some high-risk patients. In an effort to identify patients most likely to benefit from intervention, the present study sought to determine the risk factors for 1-year mortality after thoracic endovascular aortic repair.

METHODS

A retrospective review was performed on prospectively collected data from all patients undergoing thoracic endovascular aortic repair from 2002 to 2010 at a single institution. Univariate analysis and multivariate Cox proportional hazards regression analysis were used to identify risk factors associated with mortality within 1 year after thoracic endovascular aortic repair.

RESULTS

During the study period, 282 patients underwent at least 1 thoracic endovascular aortic repair; index procedures included descending aortic repair (n = 189), hybrid arch repair (n = 55), and hybrid thoracoabdominal repair (n = 38). The 30-day/in-hospital mortality was 7.4% (n = 21) and the overall 1-year mortality was 19% (n = 54). Cardiopulmonary pathologies were the most common cause of nonperioperative 1-year mortality (22%, n = 12). Multivariate modeling demonstrated 3 variables independently associated with 1-year mortality: age older than 75 years (hazard ratio, 2.26; P = .005), aortic diameter greater than 6.5 cm (hazard ratio, 2.20; P = .007), and American Society of Anesthesiologists class 4 (hazard ratio, 1.85; P = .049). A baseline creatinine greater than 1.5 mg/dL (hazard ratio, 1.79; P = .05) and congestive heart failure (hazard ratio, 1.87; P = .08) were also retained in the final model. These 5 variables explained a large proportion of the risk of 1-year mortality (C statistic = 0.74).

CONCLUSIONS

Age older than 75 years, aortic diameter greater than 6.5 cm, and American Society of Anesthesiologists class 4 are independently associated with 1-year mortality after thoracic endovascular aortic repair. These clinical characteristics may help risk-stratify patients undergoing thoracic endovascular aortic repair and identify those unlikely to derive a long-term survival benefit from the procedure.