Thoracic Aortic Surgery Research Articles

Abstract 188: Burden of Complications After Thoracic Aortic Repair Surgery Among Medicare Beneficiaries

Objective: Despite the growth in thoracic aortic repair surgery, there remain concerns about the clinical and financial impact of complications secondary to these procedures. Therefore, we leveraged Medicare administrative claims to estimate the incidence, outcomes, and spending associated with complications during 90-day episodes of thoracic aortic repair surgery. Methods and Results: Using a previously validated claims-based algorithm, we identified 11,240 Medicare fee-for-service beneficiaries hospitalized for thoracic aortic repair surgery [open type A (n=4,538), open type B (n=4,091), and thoracic endovascular aortic repair procedures (TEVAR, n=2,611)] from April 2014 to March 2015. We identified any (and total number) of the following complications within 30-day of surgery: renal failure, stroke/transient ischemic attack, respiratory failure, bleeding, pneumonia, deep vein thrombosis or pulmonary embolism, surgical site infection, paralysis, or acute myocardial infarction. Overall, 5,525 patients (49.2%) developed any complication (zero complications: 50.9%, one: 28.4%, two: 13.0%, three: 5.3%, or four or more: 2.4%). For the entire sample, 90-day episode mortality was 15.4%, which was higher in patients with any complication (23.0%) compared to patients without complications (8.1%). Adjusting for patient demographics, admission status, comorbidities, and hospital random effects, the relative odds of mortality comparing patients with and without complications was 2.41 (95% CI: 2.11-2.76) (Table). On average, 90-day episode spending was $54,668±$43,287, which was also higher among patients with any complication ($69,243 vs. $40,578, p<0.001). After similar adjustment, 90-day episode spending was 50% higher on a relative scale (95% CI: 46% to 54%), largely attributed to inpatient stays, post-acute care spending, and more frequent readmissions. Both mortality and spending increased significantly as the number of complications increased from zero to four or more. Conclusions: Complications after thoracic aortic repair were common and associated with worse outcomes and higher episode spending. Identifying and intervening upon patient and provider factors predictive of complications is essential to improving the value of thoracic aortic repair procedures.

Impact of preservation of the latissimus dorsi muscle through a left anteroaxillary thoracotomy on spinal cord protection in descending thoracic and thoraco-abdominal aortic operations†.

The presence of collateral network circulation to the spinal cord, which is reflected in the repair of a descending thoracic aortic aneurysm (dAo) and a thoraco-abdominal aortic aneurysm (TAAo), has been demonstrated in clinical and animal experimental data. The latissimus dorsi muscle (LDM) including the thoracodorsal artery might be one of the major sources of this collateral network. The objective of this study was to evaluate the impact on spinal cord safety of a left anteroaxillary thoracotomy with minimal muscle division including preservation of the LDM in surgery for dAo and TAAo. Sixty-nine patients [64 (23-85) years old; 56 men] who underwent surgical repair for dAo and TAAo were divided into 2 groups: 29 [65 (23-84) years old] with an anteroaxillary thoracotomy with LDM preservation (PL group) and 40 [61 (28-85) years old] with a lateral thoracotomy without LDM preservation (NL group). Aortic repairs were performed at the dAo in 30 patients including 14 in the PL group vs 16 in the NL group and at the TAAo in 39 patients including 15 in the PL group vs 24 in the NL group. There were 2 (2.9%) 30-day deaths; 2 (7.9%) in the PL group vs none in the NL group (P = 0.173). No strokes occurred. In patients with a femoro-femoral partial cardiopulmonary bypass with mild hypothermia, the incidence of loss of signal of motor-evoked potentials (>50%) was significantly lower in the PL group; 5.6% vs 31.8% (P = 0.039). The frequency of signal reduction of the remaining motor-evoked potential after surgery was also significantly lower in the PL group: 3.7% vs 25% (P = 0.040). Subsequently, the rate of spinal cord complications were lower in the PL group: 3.4% vs 12.5% (P = 0.188). The left anteroaxillary thoracotomy with minimal incision of the muscles including the LDM might have potential advantages for spinal cord protection via preserved intramuscular collateral circulations to the spinal cord in dAo/TAAo open repairs.

Long-term survival and frequency of reinterventions after proximal aortic surgery: a retrospective study†.

We sought to analyse perioperative outcome, long-term mortality, frequency and causes of reintervention, and survival benefit in a contemporary cohort of patients undergoing proximal thoracic aortic surgery. Participants comprised all patients undergoing open surgery for proximal thoracic aortic aneurysm (TAA) (n = 319) and thoracic aortic dissection type A (TAD) (n = 229) during 2005-2014 at the Department of Thoracic Surgery, Uppsala University Hospital. Long-term survival was compared to age- and sex-matched controls. Perioperative mortality and morbidity, event-free survival and causes of reoperation were also analysed. Long-term mortality was normalized in patients with TAA, and a survival benefit was seen as early as 20 months when corrected for time lost due to perioperative mortality. Long-term survivors undergoing surgery for TAD, on the other hand, had a 10-year mortality of 130% [95% confidence interval (95% CI) 120-140%] compared to age- and sex-matched controls. Moreover, their event-free survival was half that of patients with TAA (hazard ratio 2.3; 95% CI 1.7-3.2). Reintervention (i.e. reoperation or thoracic endovascular aortic repair) was also twice as common in the TAD patients (odds ratio 2.0; 95% CI 1.1-3.5). The dominant causes for reoperation among TAD patients were aortic insufficiency, aortic arch aneurysm and infection. Surgery for TAA is relatively safe, normalizes long-term mortality and confers an early survival benefit. However, TAD surgery carries a high risk of perioperative mortality and morbidity, as well as increased long-term mortality and risk of reintervention.

Outcomes of Thoracic Aortic Surgery in Patients With Coronary Artery Disease - Based on the Japan Adult Cardiovascular Surgery Database.

Coronary artery disease (CAD) is associated with increased morbidity and mortality after open repair of thoracic aorta. Nevertheless, the efficacy of preoperative coronary angiography (CAG) and revascularization is controversial. The aim of this study was to clarify the effect of preoperative CAD on surgical outcome by reviewing the Japan Adult Cardiovascular Database. Methods and Results: This study involved 4,596 patients who underwent open surgery for true thoracic aortic aneurysm between 2004 and 2009. After excluding patients with concomitant cardiac operation, except coronary artery bypass grafting (CABG), the remaining 1,904 patients with coronary artery stenosis included 995 cases of simultaneous CABG. The prevalence of CAD was significantly higher in patients with diabetes, renal dysfunction, hyperlipidemia, cerebrovascular disorders, peripheral artery lesions, old myocardial infarction (MI), and coronary intervention. Patients with simultaneous CABG had severe CAD compared with those without, with no other major differences in patient background noted. Thirty-day postoperative and in-hospital mortalities were higher in CAD patients. Incidence of perioperative MI was higher in patients who underwent open aortic repair with simultaneous CABG, but simultaneous CABG did not affect operative mortality. In patients with surgically treated true aortic aneurysm, CAD was frequently observed, suggesting that aggressive preoperative coronary evaluation is needed.

Sex-Related Differences in Patients Undergoing Thoracic Aortic Surgery.

Contemporary outcomes after surgical management of thoracic aortic disease have improved; however, the impact of sex-related differences is poorly understood. A total of 1653 patients (498 [30.1%] female) underwent thoracic aortic surgery with hypothermic circulatory arrest between 2002 and 2017 in 10 institutions of the Canadian Thoracic Aortic Collaborative. Outcomes of interest were in-hospital death, stroke, and a modified Society of Thoracic Surgeons-defined composite for mortality or major morbidity (stroke, renal failure, deep sternal wound infection, reoperation, prolonged ventilation). Multivariable logistic regression was used to determine independent predictors of these outcomes. Women were older (mean±SD, 66±13 years versus 61±13 years; P<0.001), with more hypertension and renal failure, but had less coronary disease, less previous cardiac surgery, and higher ejection fraction than men. Rates of aortic dissection were similar between women and men. Rates of hemiarch, and total arch repair were similar between the sexes; however, women underwent less aortic root reconstruction including aortic root replacement, Ross, or valve-sparing root operations (29% versus 45%; P<0.001). Men experienced longer cross-clamp and cardiopulmonary bypass times, but similar durations of circulatory arrest, methods of cerebral perfusion, and nadir temperatures. Women experienced a higher rate of mortality (11% versus 7.4%; P=0.02), stroke (8.8% versus 5.5%; P=0.01), and Society of Thoracic Surgeons-defined composite end point for mortality or major morbidity (31% versus 27%; P=0.04). On multivariable analyses, female sex was an independent predictor of mortality (odds ratio, 1.81; P<0.001), stroke (odds ratio, 1.90; P<0.001), and Society of Thoracic Surgeons-defined composite end point for mortality or major morbidity (odds ratio, 1.40; P<0.001). Women experience worse outcomes after thoracic aortic surgery with hypothermic circulatory arrest. Further investigation is required to better delineate which measures may reduce sex-related outcome differences after complex aortic surgery.

Antegrade thoracic endovascular aneurysm repair via the ascending aorta.

We performed antegrade thoracic endovascular aneurysm repair via the ascending aorta in selected high-risk patients scheduled for open surgery, in whom an iliofemoral or abdominal aortic approach was not feasible. We present our initial experience with this approach. Of 16 consecutive patients who underwent antegrade endovascular aneurysm repair via the ascending aorta at our institution, 3 had an emergency intervention for rupture and 3 had an urgent intervention for impending rupture or complicated aortic dissection. The procedure was scheduled in 10 patients. The median patient age was 77 years. In 13 patients, one or more concomitant procedures were performed. In 6 patients, vascular access for endovascular aneurysm repair was obtained via a branch of the replacement graft. In 10 patients, direct cannulation of the ascending aorta was carried out using 2 pursestring sutures. The initial success rate was 100%. Early mortality occurred in 2 (12.5%) patients because of multiple organ failure in one and heart failure in the other. No patient required a second intervention during follow-up. The mean duration of follow-up was 19 months. The antegrade approach is a useful alternative in patients with no access suitable for endovascular aneurysm repair and who are not appropriate candidates for open conventional thoracic aortic surgery. This approach is applicable to selected patients.

Retrograde autologous priming in surgery of thoracic aortic aneurysm.

Surgery of thoracic aortic aneurysm (TAA) is associated with blood loss and coagulopathy and a high need for red blood cell (RBC) volume. Retrograde autologous priming (RAP) decreases haemodilution during cardiopulmonary bypass (CPB). The aim of this study was to show the effect of RAP during surgery of TAA repair on haemodilution, the need for RBC transfusion and the postoperative course compared to conventional CPB (cCPB). A retrospective study was performed on 120 patients with TAA. Half of these patients underwent cCPB and the other half received RAP. Statistical analysis was performed using IBM SPSS statistics 23. The χ2 test, the Fisher's exact tests, the independent t-test and the Mann-Whitney U-test were used. Statistical significance was assumed at P-value <0.05. Lower blood product requirements were observed for the RAP group regarding the transfusion of intraoperative RBC (0.87 ± 1.33 vs 1.97 ± 2.43, P = 0.013), postoperative RBC (0.57 ± 1.4 vs 1.32 ± 1.82, P = 0.002) and postoperative fresh frozen plasma (0.52 ± 1.63 vs 1.48 ± 3.32, P = 0.036). The postoperative drainage loss showed significantly lower measurements for the RAP group after 6 h (295.9 ± 342.6 vs 490.6 ± 414.4 ml, P ≤ 0.001), 12 h (450.1 ± 415.5 vs 652.1 ± 463.9 ml, P < 0.001) and 24 h (693.1 ± 483.9 vs 866.4 ± 508.4 ml, P = 0.004). RAP is a safe and easy method to reduce RBC transfusion in TAA surgery without any adverse effects on the clinical outcome. We were also able to show beneficial effects on fresh frozen plasma requirements and postoperative chest drainage volume. Furthermore, improved microcirculation can be suspected. In consequence, we have implemented RAP as a clinical standard during thoracic aortic surgery.

Serum Neuron-Specific Enolase Level as Predictor of Neurologic Outcome after Aortic Surgery

This study aimed to evaluate the significance of serum neuron-specific enolase (NSE) level as a predictor of neurologic injury in thoracic aortic surgery. We neurologically assessed 60 consecutive patients who underwent thoracic aortic surgery for thoracic aortic aneurysm (n = 26) and aortic dissection (n = 34). Using moderate hypothermic circulatory arrest with antegrade cerebral perfusion, total arch replacement and hemiarch replacement were performed in 37 and 23 patients, respectively. Serum NSE levels in venous blood samples drawn before surgery and at 1 day after surgery were measured. Severity of neurologic injury was categorized as either uncomplicated (n = 48), temporary neurologic dysfunction (TND, n = 5), or permanent neurologic dysfunction (PND, n = 7). The extent of stroke was estimated on computed tomography or magnetic resonance imaging. The NSE level significantly differed among the three groups (PND > TND > uncomplicated) on the first postoperative day. Receiver-operating characteristic curve analysis showed that the cutoff value of NSE level was 34.14 ng/mL for neurologic injury (sensitivity, 0.769; specificity, 0.851) and 43.56 ng/mL for PND (sensitivity, 1.000; specificity, 0.963). The NSE level significantly correlated with the extent of stroke (r = 0.61, p < 0.001). Serum NSE level is a significant predictor of adverse neurologic outcomes and extent of stroke after thoracic aortic surgery.

Thoracic Aortic, Aortic Valve, and Mitral Valve Surgery in Pediatric and Young Adult Patients With Marfan Syndrome: Characteristics and Outcomes

Patients with Marfan syndrome (MFS) often require surgical intervention on the mitral valve (MV), aortic root or valve (AV), or thoracic aorta (TA) during childhood and adolescence. We aim to utilize a national database to evaluate outcomes in pediatric and young adult patients with MFS undergoing MV, AV, and aortic surgical procedures, and describe factors associated with increased mortality. The Pediatric Hospital Information System (PHIS) database, a multi-institutional administrative database of 48 pediatric hospitals, was queried for patients less than 25 years of age with a diagnosis of MFS (ICD-9 759.82) who underwent MV, AV, or thoracic aortic surgery between January 2004 and October 2015. We assessed comorbidities and complications, and performed univariate analysis to evaluate factors associated with inpatient mortality. Included were 321 hospital encounters in 294 patients. Fifty-one patients underwent 54 MV surgeries, 213 patients underwent 224 aortic/AV surgeries, and 43 patients underwent both MV and aortic/AV surgery in the same encounter. Postoperative complications were common for all surgeries (46.3% for MV procedures and 45.5% for aortic/AV procedures). Overall in-hospital mortality was 2.2% (3.7% for MV procedures, 1.8% for AV/aortic procedures, and 2.3% in the combined MV and aortic/AV procedure group). Aortic dissection or rupture was reported in 3.4%, with no in-hospital mortalities. Death after MV as well as after aortic/AV surgery was associated with younger age. Postoperative complications are common in pediatric and young adult patients with MFS after intervention on the MV, AV, and TA, although mortality is relatively low.

Innominate vs. Axillary Artery Cannulation in Aortic Surgery: a Systematic Review and Meta-Analysis.

ObjectiveTo investigate whether axillary artery cannulation has supremacy over innominate artery cannulation in thoracic aortic surgery.MethodsA comprehensive search was undertaken among the four major databases (PubMed, Excerpta Medica dataBASE [EMBASE], Scopus, and Ovid) to identify all randomized and nonrandomized controlled trials comparing axillary to innominate artery cannulation in thoracic aortic surgery. Databases were evaluated and assessed up to March 2017.ResultsOnly three studies fulfilled the criteria for this meta-analysis, including 534 patients. Cardiopulmonary bypass time was significantly shorter in the innominate group (P=0.004). However, the innominate group had significantly higher risk of prolonged intubation > 48 hours (P=0.04) than the axillary group. Further analysis revealed no significant difference between the innominate and axillary groups for deep hypothermic circulatory arrest time (P=0.06). The relative risks for temporary and permanent neurological deficits as well as in-hospital mortality were not significantly different for both groups (P=0.90, P=0.49, and P=0.55, respectively). Length of hospital stay was similar for both groups.ConclusionThere is no superiority of axillary over innominate artery cannulation in thoracic aortic surgery in terms of perioperative outcomes; however, as the studies were limited, larger scale comparative studies are required to provide a solid evidence base for choosing optimal arterial cannulation site.

Left Ventricular Pseudoaneurysm Caused by a Left Ventricular Venting Catheter via the Right Superior Pulmonary Vein during Thoracic Aortic Surgery: A Case Report

A left ventricular (LV) pseudoaneurysm is one of the complications of acute myocardial infarction. It is also reported after chest trauma, cardiac surgery, and endocarditis. We report a rare case of an LV pseudoaneurysm induced by an LV venting catheter through the right superior pulmonary vein during thoracic aortic surgery. A 77-year-old man was referred for surgical repair of a distal aortic arch aneurysm. He underwent total aortic arch reconstruction with the frozen elephant trunk technique. The early postoperative period was uneventful. Postoperative contrast computed tomography and transthoracic echocardiography (TTE) revealed a pseudoaneurysm with a narrow neck at the apex of the LV that had sub-clinically progressed. Because of the risk of spontaneous rupture, an urgent aneurysmectomy was performed via a repeat sternotomy. Under cardioplegic arrest, the pseudoaneurysm was opened and the small orifice, which communicated with the LV, was confirmed. No myocardial ischemic changes were observed around the orifice. The pseudoaneurysm was thought to be induced by endocardial laceration by the tip of the venting catheter. The pseudoaneurysm was closed by linear repair reinforced with felt strips. The patient recovered well and was discharged 18 days after the second surgery. TTE showed no recurrence of LV aneurysm at the last follow-up.

Effect of Autotransfusion Using Intraoperative Predonated Autologous Blood on Coagulopathy during Thoracic Aortic Surgery: A Randomized Controlled Trial.

Background: Intraoperative predonated autologous blood transfusion is thought to replenish platelets and coagulation factors and ameliorate coagulopathy. This study aimed to evaluate whether intraoperative predonated autotransfusion improves coagulopathy during thoracic aortic surgery.Methods: Patients who underwent thoracic aortic surgery were randomized into two groups as follows: those who received intraoperative predonated blood (group A: n = 31) and those who did not receive (group N: n = 22). In group A, autologous blood was retransfused immediately after cessation of cardiopulmonary bypass (c-CPB).Results: The mean intraoperative allogenic blood or blood product transfusion requirements were significantly lesser in group A than in group N (packed red blood cells [RBCs]: 6.3 ± 5.1 vs. 9.1 ± 4.3 units, p = 0.04; fresh frozen plasma [FFP]: 3.0 ± 4.1 vs. 6.1 ± 5.7 units, p = 0.03). After c-CPB, hemoglobin (Hb) level, platelet count, and coagulopathy became significantly worse than those at the start of surgery in both the groups. However, the values significantly improved 30 min after c-CPB only in group A. Renal function was significantly worse in group N.Conclusions: Intraoperative predonated autotransfusion significantly improved coagulopathy, with reduced allogeneic blood transfusion volume during thoracic aortic surgery. Furthermore, reduction of allogeneic blood transfusion may reduce the adverse effects on renal function.

Fluid status optimization during autologous blood exfusion in thoracic aortic surgery

Fluid status optimization during autologous blood exfusion in thoracic aortic surgery

Minimally invasive approach in thoracic aortic surgery: a single center experience

Minimally invasive approach in thoracic aortic surgery: a single center experience

A Prospective Survey Comparing Patients’ Experience of a Nurse-Led Clinic and Consultant-Led Clinic for Surveillance of Patients with Dilatation of the Intrathoracic Aorta

Background: Increasing workload in consultant-led clinics often means patients to wait a long time for clinic appointments. To address this, there is an increasing trend in developing nurse-led clinics across many specialities in the National Health Service. This study aims to assess whether the implementation of a nurse-led clinic in thoracic aortic surgery will optimise the utilisation of health care services and improve overall patient satisfaction. Methods: 80 follow-up patients were asked to complete a questionnaire following their appointment in an aortic clinic, which was led either by a consultant (n = 40) or an aortic specialist nurse (n = 40). All patients seen by a nurse in the clinic were assessed by a consultant surgeon prior to the clinic for suitability. No new patients were seen by a nurse. Any patient with an aortic dimension of 5 cm or greater was seen by the consultant. If there were any complicated clinical features, the patient was seen in the consultant-led clinic. Patients were asked questions about their time spent with the respective health care professionals across 12 categories (punctuality, preparedness, understanding of concerns, clarity of speech, listening, respect, explaining, letting you talk, putting you at ease, emotional support, advice and advice for next follow-up). Patients rated each category using an ordinal scale from 0 - 10. Results: Patient scores were greater in nurse-led clinics compared to consultant-led clinics across a number of categories although only punctuality reached significance (mean 9.2 vs. 6.8, p 0.05). Conclusion: Patients were highly satisfied with the nurse-led clinic across all categories, with greater satisfaction for punctuality. These findings suggest that a nurse-led clinic can be implemented for the management of carefully selected thoracic aortic surgery patient without reduction in patient satisfaction.

ЭФФЕКТИВНОСТЬ ОТЕЧЕСТВЕННОГО РЕКОМБИНАНТНОГО АКТИВИРОВАННОГО ФАКТОРА VII ДЛЯ ЛЕЧЕНИЯ КРОВОТЕЧЕНИЙ И НОРМАЛИЗАЦИИ ГЕМОСТАЗА ПРИ ОПЕРАЦИЯХ НА ГРУДНОМ ОТДЕЛЕ АОРТЫ

Goal: to evaluate the efficacy and safety of domestic (home-produced) recombinant factor VIIa (Coagil VII) for massive bleeding and haemostasis disordes treatment in thoracic aorta surgery. Methods. 82 patients undergoing surgery on thoracic aorta with cardiopulmonary bypass and circulatory arrest s were divided in 3 groups. The 1 group included 27 patients with uncomplicated operations, moderate hemorrhage and standart protocol hemostasis management after cardiopulmonary bypass. In 2 group of 26 patients with massive hemorrhage the thrombocytes were used for treatment. In 3 main group (29 patients) with continious bleeding Coagil VII was used additionally. Results. Coagil-VII induction in dose 37–100 mcg/kg was accompanied by prominent decreasing of wound bleeding in 20–25 min, that it allowed to perform sternoraphia. The volume of transfused erythrocytes , fresh frozen plasma and postoperative blood loss were less in comparison with control group and patients where the platelets were used. There were no any complications after Coagil VII induction. Analysis of the hemostasis indices showed decrease of APTT by 13%, PTT by 17% and MNO by 36% after Coagil VII induction. Conclusion. The domestic recombinant factor VIIa (Coagil VII) in dose 66 ± 19,5 mcg/kg is an effective and safe medicine for bleeding and hаemostasis desordes treatment in the patients undergoing aortic surgery

Postoperative acute respiratory failure in cardiac surgery.

To evaluate incidence, causes and outcomes of acute respiratory failure (ARF) in patients after cardiac and aortic surgery. A retrospective trial included 3972 patients after elective cardiovascular procedures for the period 2013-2017. Inclusion criterion: sustained reduction of pulmonary function (PaO2/FiO2<300 mm Hg) in the postoperative period required mechanical ventilation or non-invasive positive pressure mask ventilation for at least 24 h. ARF developed in 138 (3.5%) cases. It was observed after aortic surgery as a rule (11.2%). Other operations were followed by ARF in 1-3.5% of cases. Incidence of ARF was less after off-pump coronary artery bypass surgery compared with on-pump interventions (1.6 vs. 3.5%, p=0.0469). Acute respiratory distress syndrome was the main reason of ARF (n=37, 26.8%). ARF as a consequence of neurological complications were observed in 25 (18.1%) patients. Exacerbation of COPD and bronchial asthma occurred in 23 (16.1%) patients, paresis of the diaphragm - in 15 (11.7%). In 15 (10.8%) patients, ARF was caused by pneumonia, in 12 (8.7%) cases - pulmonary congestion, in 10 (7.2%) patients - lung injury and haemothorax. Overall ARDS-associated mortality was 21.6%; 15.1% of patients with mild and moderate ARDS died. Severe ARDS was followed by unfavorable outcome in 75% of patients. Nosocomial pneumonia was found in 40.6%, there were no fatal outcomes from this complication. Acute respiratory failure developed in 3.5% of cardiac patients and was common thoracic and thoracoabdominal aortic surgery. The leading cause of mortality was ARDS (mortality rate 15.1% in mild and moderate syndrome, 75% in severe course of ARDS). Nosocomial pneumonia was diagnosed in 1.4% of patients and was not fatal.

Side Graft Axillary Artery Cannulation in Proximal Thoracic Aortic Surgery

Side Graft Axillary Artery Cannulation in Proximal Thoracic Aortic Surgery

Spinal Cord Protection for Thoracic Aortic Surgery: Bench to Bedside

This article summarizes the anatomically driven pathophysiology of spinal cord injury, the impact of ischemia reperfusion on the cellular level, current research in developing neuronal ischemic tolerance, and promotion of collateralization. It addresses neuroprotective strategies in modern clinical practice, current pharmacologic interventions, and continued challenges in the management of complex aortic disease. The pathophysiology of spinal cord injury includes disruption and recovery of collateral blood flow and the effects of malperfusion on the spinal cord. The optimal approach to spinal cord protection is to employ an integrated and protocolized set of strategies to simultaneously maximize spinal cord blood flow, improve ischemic tolerance, and promote collateralization. In the laboratory setting, investigation should continue to pursue a more granular understanding of ischemic injury and seek to translate protective therapies to clinical practice.

Body Mass Index is an Independent Predictor of Acute Kidney Injury after Aortic Total Arch Surgery for Type A Acute Aortic Dissection: A Retrospective Cohort Study

Background: Thoracic aortic surgery and obesity are both associated with risk of acute kidney injury (AKI). We hypothesized that the risk of postoperative AKI increases when the body mass index (BMI) increases in patients undergoing aortic total arch surgery for Type A acute aortic dissection (AAD). Methods: We conducted a population-based cohort study in Beijing anzhen hospital from December 2015 to April 2017. All AAD patients receiving aortic total arch surgery were included. BMI was calculated on the basis of height and weight recorded on the day of hospital admission preoperatively. AKI was defined by the Kidney Disease Improving Global Outcomes criteria. Findings: We included 115 consecutive in this timeframe. The overall incidence of AKI was 53·0% (n=61). Mean age was 47·8±10·7 years; 25·2% were women. Mean BMI was 26·2±3·9kg/m2. In-hospital mortality was significantly higher in the AKI group (13·11% vs 1·85%; P=0·025). Multivariate logistic regression revealed that BMI was independently associated with the development of postoperative AKI after adjust other confounding factors (odds ratio [OR], 1·22; 95% confidence interval [CI], 1·07-1·39; P =0·004). Interpretation: Body mass index is independently associated with an increased risk of acute kidney injury after aortic total arch surgery. Further understanding of the molecular basis of this association is critical to the design of preventative strategies. Funding Statement: This study was supported by National Key R&D Program of China（2017YFC1308000）and the Beijing Lab for Cardiovascular Precision Medicine, Beijing, China. PXM2017_014226_000037. Declaration of Interests: The authors have declared that no conflicts of interest exist. Ethics Approval Statement: This study was approved by the human research and development committees of the Beijing Anzhen Hospital and was adhered to the rules of the Declaration of Helsinki and principles of Good Clinical Practice. Individual consent was waived for the retrospective study.