Renal perfusion with histidine-tryptophan-ketoglutarate compared with Ringer's solution in patients undergoing thoracoabdominal aortic open repair

Structure-function integrated biodegradable Mg/polymer composites: Design, manufacturing, properties, and biomedical applications

Mg is a typical biodegradable metal widely used for biomedical applications due to its considerable mechanical properties and bioactivity. Biodegradable polymers have attracted great interest owing to their favorable processability and inclusiveness. However, it is challenging for the degradation rates of Mg or polymers to precisely match tissue repair processes, and the significant changes in local pH during degradation hinder tissue repair. The concept of combining Mg with polymers is proposed to overcome the shortcomings of materials, aiming to meet repair needs from various aspects such as mechanics and biology. Therefore, it is essential to systematically understand the behavior of biodegradable Mg/polymer composite (BMPC) from the design, manufacturing, mechanical properties, degradation, and biological effects. In this review, we elaborate on the design concepts and manufacturing strategies of high-strength BMPC, the "structure-function" relationship between the microstructures and mechanical properties of composites, the variation in the degradation rate due to endogenous and exogenous factors, and the establishment of advanced degradation research platform. Additionally, the interplay among composite components during degradation and the biological function of composites under non-responsive/stimuli-responsive platforms are also discussed. Finally, we hope that this review will benefit future clinical applications of "structure-function" integrated biomaterials.

Efficacy and Safety of Endovascular Fenestrated and Branched Grafts Versus Open Surgery in Thoracoabdominal Aortic Aneurysm Repair: An Updated Systematic Review, Meta-analysis, and Meta-regression

OBJECTIVE

To provide an updated systematic review and meta-analysis with meta-regression of efficacy and safety of fenestrated/branched endovascular repair of thoracoabdominal aortic aneurysms (TAAAs) compared with open repair.

BACKGROUND

Endovascular repair of TAAAs may be a promising alternative to open surgery by reducing invasiveness and expanding the eligible population, but evidence remains limited.

METHODS

We applied "Prepared Items for Systematic Reviews and Meta-analysis" guidelines to retrieve, quantitatively pool, and critically evaluate the efficacy and safety (including 30-day mortality, reintervention, spinal cord injury [SCI], and renal injury) of both approaches. Original studies were retrieved from PubMed, Embase, and Cochrane Library until April 20, 2022, excluding papers reporting <10 patients. Pooled proportions and means were determined using a random-effect model. Heterogeneity between studies was evaluated with I2 statistics.

RESULTS

Sixty-four studies met the predefined inclusion criteria. Endovascular cohort patients were older and had higher rates of comorbidities. Endovascular repair was associated with similar proportions of mortality (0.07, 95% confidence intervals [CI]: 0.06-0.08) compared with open repair (0.09, 95% CI: 0.08-0.12; P = 0.22), higher proportions of reintervention (0.19, 95% CI: 0.13-0.26 vs 0.06, 95% CI: 0.04-0.10; P < 0.01), similar proportions of transient SCI (0.07, 95% CI: 0.05-0.09 vs 0.06, 95% CI: 0.05-0.08; P = 0.28), lower proportions of permanent SCI (0.04, 95% CI: 0.03-0.05 vs 0.06, 95% CI: 0.05-0.07; P < 0.01), and renal injury (0.08, 95% CI: 0.06-0.10 vs 0.13, 95% CI: 0.09-0.17; P = 0.02). Results were affected by high heterogeneity and potential publication bias.

CONCLUSIONS

Despite these limitations and the lack of randomized trials, this meta-analysis suggests that endovascular TAAA repair could be a safer alternative to the open approach.

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

Five-factors Modified Frailty Index role as predictors of outcomes after proximal abdominal aortic aneurysms

BACKGROUND

The aim of the study was to evaluate the correlation between frailty, measured by the Five-Factor Modified Frailty Index (mFI-5) and mortality and all major adverse events (MAE) in patients who underwent proximal abdominal aortic aneurysm (p-AAA) open surgery (OS).

METHODS

Data of all elective patients submitted to p-AAA OS from 2010 to 2021 were recorded. Primary endpoints were 30-day mortality and mid-term survival and secondary endpoints included postoperative acute kidney injury (AKI), freedom from aortic reintervention and any MAE. The impact of frailty was assessed by univariate and multivariate analysis; mid-term overall survival were estimated using Kaplan-Meier method (log-rank test).

RESULTS

Two-hundred twenty-one patients (197 male, 24 female; aged 72.2±7.4) were included. Thirty-seven (16.4%) were octogenarians (>80 years). The mFI-5 was assessed in the entire group: mean mFI-5 was 0.29±0.12. One-hundred patients (100/221, 45.25%, 91:9 male-to-female ratio) were defined "frail" considering the mFI-5 cut-off >0.25. At univariate analysis a correlation was found between mFI-5>0.25 and mid-term mortality (Pearson correlation [r] 0.280, P<0.001) and AKI (r=0.146, P=0.030). No correlation with 30-day mortality was found (P not significant). At multivariate analysis mFI-5>0.25 increased the risk for midterm mortality (odds ratio 3.32, P=0.021) and postoperative AKI (OR 2.09, P<0.001). The effect of mFI-5>0.25 on mid-term mortality persisted after adjustment for age (P<0.001). Survival was estimated with Kaplan-Meyer method (mean follow-up of 52.7 months, 95% CI: 48.6-56.8); 68 (30.7%) deaths were recorded: 23 among non-frail patients (19.0%) and 45 among frail patients (45/100, 45%, P<0.001).

CONCLUSIONS

These findings suggest that mFI-5 is a tool capable to identify "frail" patients, who appear to be at increased risk of postoperative AKI and mid-term mortality, but not 30-day mortality. Five-factor modified Frailty Index assessment is simple, fast and can be widely applied in surgical practice to perform appropriate risk stratifications.

Silver acetate and Triclosan Antimicrobial Graft Evaluation for surgical Repair of aortic disease (STAGER Study)

BACKGROUND

The aim of this study was to assess perioperative and late performance of a silver acetate and triclosan impregnated antimicrobial vascular graft (Intergard Synergy, Intervascular SAS, La Ciotat, France) during open surgical repair of abdominal aortic aneurysms (AAA), and to compare it with standard polyester grafts ones.

METHODS

This retrospective single-centre study (STAGER Study, clinicaltrials.gov: NCT04557254) included patients undergone non-infectious AAA surgical repair between 2012 and 2019, divided into two groups according to the implanted aortic prosthesis: standard polyester graft (PolyG) and silver-triclosan graft (SynG). Early primary endpoints were 30-day mortality, major adverse events (MAEs), and reintervention rates; late primary endpoints were overall and aortic-related survival, reintervention-free survival, and graft infection rate at a mean follow-up (FU) of 49.4±26.8 months.

RESULTS

Five hundred forty-seven patients were included [PolyG 49%, and SynG 51%]. Both groups were substantially homogeneous in risk factors and demographics. Two patients died within 30 days. In-hospital MAE rate [PolyG 14.2% vs. SynG 10.7%; P=.248] and 30-day reintervention rate were not significantly different [PolyG 2.6% vs. SynG 1.4%; P=.374]. At 5 years, overall survival in the PolyG and SynG groups were 85% and 84%, respectively. Reintervention-free survival was 82% for both groups. Aortic-related survival was 95% and 96%, respectively. Graft infection was observed in 8 (3.3%) PolyG patients and 5 (1.8%) SynG patients.

CONCLUSIONS

Silver acetate and triclosan impregnated grafts demonstrated good early and mid-term results, being considered safe and durable for AAA open repair. Similar graft infection and related death rates were observed compared to polyester standard grafts, supporting non-superiority of one graft over the other.

Intraoperative immunomodulation during left heart bypass in open thoracoabdominal aortic aneurysm repair

Despite the technical innovations introduced in the previous decades, open thoracoabdominal aortic aneurysm repair still represents an enormous challenge for patients and surgeons. Logically, the systemic inflammatory response resulting from these massive operations appears considerable; however, the response has never been thoroughly investigated. In addition, intraoperative adjuncts to modulate the postoperative activation of the immune system have not yet been introduced into clinical practice. We report a case of intraoperative hemadsorption during open repair of a thoracoabdominal aortic aneurysm through the introduction of a CytoSorb device (CytoSorbents Corp) in the left heart bypass circuit. The technique appeared feasible and safe and probably contributed to the good clinical outcomes.

The anesthesiologist's perspective on emergency aortic surgery: Preoperative optimization, intraoperative management, and postoperative surveillance

The management of emergencies related to the aorta requires a multidisciplinary approach involving various health care professionals. Despite technological advancements in treatment methods, the risks and mortality rates associated with surgery remain high. In the emergency department, definitive diagnosis is usually obtained through computed tomography angiography, and management focuses on controlling blood pressure and treating symptoms to prevent further deterioration. Preoperative resuscitation is the main focus, followed by intraoperative management aimed at stabilizing the patient's hemodynamics, controlling bleeding, and protecting vital organs. After the operation, factors such as organ protection, transfusion management, pain control, and overall patient care must be taken into account. Endovascular techniques are becoming more common in surgical treatment, but they also present new challenges in terms of complications and outcomes. It is recommended that patients with suspected ruptured abdominal aortic aneurysms be transferred to facilities with both open and endovascular treatment options and a track record of successful outcomes to ensure the best patient care and long-term results. To achieve optimal patient outcomes, close collaboration and regular case discussions between health care professionals are necessary, as well as participation in educational programs to promote a culture of teamwork and continuous improvement.

Outcomes following Management of Complex Thoracoabdominal Aneurysm by an Open Approach

BACKGROUND

In the last decade, advances in surgical techniques, and the introduction of adjuncts for organ protection, have modified the approach for thoracoabdominal aortic aneurysm (TAAA) surgical repair. The aim of this study is to determine whether the contemporary approach influenced the outcomes.

METHODS

From 1989 to 2022, patients who had received elective open surgical repair (OSR) for TAAA at our institution were retrospectively analyzed. This series has been divided in two groups: Group 1 (1989-2009), and Group 2 (2010-2022). Patients included in Group 1 were those treated with a selective use of adjuncts, and Group 2 included patients treated with the systematic use of adjuncts.

RESULTS

A total of 1107 patients were treated (Group 1: 455; Group 2: 652). The surgical management was significantly different between the two groups. The in-hospital mortality was significantly different between the two groups (Group 1: 13.4%, Group 2: 8.1%; p 0.004), as was the rate of permanent spinal cord ischemia (Group 1: 11.9%, Group 2: 7.8%; p 0.023). Renal and respiratory failure were reduced in Group 2, but not significantly.

CONCLUSIONS

The use of the adjuncts enabled the achievement of improvement in mortality and SCI prevention in TAAA OSR. Although a refined surgical technique, mortality and morbidity are still noteworthy in this complex aortic field.

The application of modular multifunctional left heart bypass circuit system integrated with ultrafiltration in thoracoabdominal aortic aneurysm repair

Open thoracoabdominal aortic aneurysm (TAAA) repair is a complex and challenging operation with a high incidence of serious complications, and high perioperative mortality and morbidity. Left heart bypass (LHB) is a circulatory support system used to perfuse the distal aorta during TAAA operation, and the advantages of LHB include guaranteeing distal perfusion, reducing the use of heparin, and diminishing the risk of bleeding and postoperative neurological deficits. In China, the circuit for TAAA repair is deficient, and far from the perfusion requirements. We designed a modular multifunctional LHB circuit for TAAA repair. The modular circuit consisted of cannulation pipelines, functional consumables connection pipelines, and accessory pipelines. The accessory pipelines make up lines for selective visceral perfusion and kidney perfusion, suckers and rapid infusion. The circuit can be assembled according to surgical requirements. The ultrafilter and heat exchanger are integrated into the circuit to fulfill the basic demands of LHB. The LHB circuit also has pipelines for selective visceral perfusion to the celiac artery and superior mesenteric artery and renal perfusion pipelines. Meanwhile, the reserved pipelines facilitate the quick switch from LHB to conventional cardiopulmonary bypass (CPB). The reserved pipelines reduce the time of reassembling the CPB circuit. Moreover, the rapid infusion was integrated into the LHB circuit, which can rapid infusion when massive hemorrhage during the open procedures such as exposure and reconstruction of the aorta. The ultrafiltration can diminish the consequent hemodilution of hemorrhage and rapid infusion. A hemoperfusion cartridge also can be added to reduce the systemic inflammatory during operation. The circuit can meet the needs of LHB and quickly switch to conventional CPB. No oxygenator was required during LHB, which reduce the use of heparin and reduce the risk of bleeding. The heat exchanger contributes to temperature regulation; ultrafiltration, arterial filter, and rapid-infusion facilitated the blood volume management and are useful to maintain hemodynamic stability. This circuit made the assembly of the LHB circuit more easily, and more efficient, which may contribute to the TAAA repair operation performed in lower volume centers easily. 26 patients who received TAAA repair under the modular multifunctional LHB from January 2018-March 2022 were analyzed, and we achieved acceptable clinical outcomes. The in-hospital mortality and 30-day postoperative mortality were 15.4%, and the postoperative incidences of paraparesis (4%), stroke (4%), and AKI need hemodialysis (12%) were not particularly high, based on the limited patients sample size in short research period duration.

Open Thoracoabdominal Aortic Procedures following Endovascular Intervention

Open conversion of thoracoabdominal aortic (TAA) disease after failed attempts of endovascular treatment is increasingly required. The main causes are endoleak, endograft failure, infection, disease progression, or persistent false lumen perfusion in dissected aortas. Mortality and morbidity rates are high, higher than after standard TAA open repair. Therefore, this surgery should be performed only in dedicated centers by experienced teams. Specific perioperative organ protection protocols, as well as surgical techniques, are crucial to guarantee acceptable results.

Contemporary Outcomes of in Situ Open Surgical Repair of Mid-Portion and Distal Renal Artery Aneurysms

INTRODUCTION

The best management of renal artery aneurysms (RAAs) remains controversial, especially when they are located from the mid to distal portions of the main renal artery. Our aim is to evaluate our 10-year experience with in situ open surgical repairs from a cohort of non-proximal RAAs at a single vascular surgery center.

METHODS

A retrospective review of a prospectively maintained database of all patients who underwent RAA in situ repairs located from the mid to distal portions of the renal artery at our Institution was performed between 2009 and 2020. Data on patient demographics, comorbidities, aneurysm location and morphology, type of in situ technique, and perioperative data were assessed. Postoperative biomarkers and renal function were collected, and mid-term follow-up results were analyzed.

RESULTS

A total of 15 RAA located at mid and distal portions of the renal artery repaired with in situ techniques were performed in 15 patients (nine men, mean age 62.4 ± 6.36 years). At diagnosis, 12 patients were asymptomatic; a history of abdominal pain was found in one patient, and two patients had drug-resistant hypertension. Two patients had already undergone previous unsuccessful attempts of endovascular treatment. All patients presented an aneurysm diameter >20 mm (mean diameter 2.75 ± 5 mm). At admission, mean serum creatinine and glomerular filtration rate were 1.10 ± 0.23 mg/dL and 69.8 ± 9.8 mL/min/1.73 m², respectively. Nine lesions were present in the distal portion of the renal artery, with 4 cases having ≥3 efferent branches and the other 5 with two efferent branches. The other six RAAs were in the mid-portion: in 4 cases, one efferent branch, and in 2 cases, two efferent branches were involved. All patients underwent in situ open repair: an end-to-end anastomosis was performed in 9 cases, aneurysm resection with primary closure in 3 cases, bypass with graft interposition in 2 cases (one iliac-renal reconstruction), and with vein interposition in 1 case. The mean renal ischemia time was 21.8 ± 9.4 min. A significant decrease on renal function was not observed (mean glomerular filtration rate at discharge: 64.8 ± 12.0 mL/min/1.73m²; P > 0.22). During recovery, one patient developed retroperitoneal hematoma treated conservatively. During follow-up (mean 46 months, range 2-135), one patient developed occlusion of a terminal renal artery branch without decreased kidney function.

CONCLUSION

In situ techniques for RAA from the mid to distal portions of the renal artery are technically complex; however, based on our results, these procedures were safe and effective, providing satisfactory early and mid-term outcomes.