Kidney protection in thoracoabdominal aortic aneurysm surgery

Guidelines on prevention, diagnosis and treatment of thoracic and thoracoabdominal aortic pathology: updates from the Italian Society of Vascular and Endovascular Surgery (SICVE)

The aim of these Guidelines was to refresh and enhance the earlier 2015 Italian Guidelines regarding Thoracic and Thoracic - Abdominal Aortic Disease, aligning them with the National Guidelines System (SNLG) to assist all healthcare professionals in adopting the most appropriate treatment approach for this condition. The update utilized the GRADE-SIGN version methodology, adhering to the AGREE checklist for quality reporting. The initial step involved crafting clinical questions in the PICO (Population, Intervention, Comparison, Outcome) format to base the Recommendations on. Following this, systematic literature reviews were conducted for each PICO question or for related clusters of questions, leading to article selection and evaluation of their methodological quality via qualitative checklists. Subsequently, a Considered Judgment form was completed for each clinical question, assessing the overall evidence to facilitate the conversion from evidence level to recommendation strength and direction. These guidelines outline the best practices for managing thoracic-abdominal aortic disease, with a focus on screening and monitoring. They explore medical treatments and criteria for surgical intervention, including a thorough preoperative analysis of the patient's history and an assessment of surgical risks. Following the determination of surgical necessity, the guidelines compare traditional open surgery with endovascular procedures, paying particular attention to define new recommendations where there were not. Systematic literature reviews were executed for each PICO question. Considered judgments were made through evaluating the evidence level, and the recommendations, direction and strength. The document concludes by outlining protocols for both immediate and prolonged postoperative care. Recent literature has not only validated and refined previous recommendations but also introduced new ones on emerging topics.

Open repair of thoracoabdominal aortic aneurysms under left heart bypass

BACKGROUND

Thoracoabdominal aortic aneurysm (TAAA) open surgical repair (OSR) is a highly complex procedure associated with significant mortality and morbidity. Despite advancements in surgical techniques and organ protection strategies, TAAA OSR remains a challenge. This study analyzes nearly 35 years of experience at a single center, with a focus on the evolution of surgical approaches and adjuncts, particularly the use of left heart bypass (LHBP) for organ perfusion maintenance.

METHODS

This retrospective study was performed on all the patients who underwent elective TAAA OSR at our institution between 1989 and 2024. Patients were divided into two groups: Group 1 (1989-2009), where adjuncts were used selectively, and Group 2 (2010-2024), where a systematic multimodal approach was implemented. Preoperative, intraoperative, and postoperative data were analyzed to assess the impact of evolving surgical techniques, adjuncts, and patient outcomes. Key adjuncts included cerebrospinal fluid drainage (CSFD), motor and somatosensory evoked potentials (MEP&SSEP), LHBP, renal perfusion strategy, and rotational thromboelastometry.

RESULTS

In total, 1211 patients underwent elective TAAA OSR, with 455 patients in Group 1 and 756 in Group 2. A modified surgical approach was employed in the two groups, with significant differences in terms of sites of aortic cross-clamping, techniques for vessel reconstruction, and approach in the management of intercostal artery. In addition, significant differences between the groups were observed for what concern the use of adjuncts. Regarding the outcomes, Group 2 demonstrated a significantly lower 30-day mortality rate (7.5% in Group 2 vs. 13.4% in Group 1; P=0.001), and a reduction in permanent spinal cord ischemia (SCI) (7.4% in Group 2 vs. 11.9% in Group 1; P=0.012). Additionally, Group 2 exhibited trends toward reduced respiratory failure and renal complications, but these differences were not statistically significant.

CONCLUSIONS

This single-center experience highlights the evolution of TAAA OSR over 35 years, demonstrating a significant reduction in mortality and SCI with the use of a comprehensive, multimodal approach. Although there were improvements in postoperative complications, further advancements are needed in this complex field to optimize outcomes. The ongoing refinement of surgical techniques and adjuncts continues to play a crucial role in improving patient care.

Semiautomatic volume measure of kidney vascular territories on CT angiography to plan aortic aneurysm repair in patients with horseshoe kidney

Surgical repair of abdominal aortic aneurism (AAA) with horseshoe kidney (HK) is challenging because of several accessory renal arteries (RAs), variable in number, branches, and vascular territories, with subsequent variable renal damage. The identification of RAs and vascular territories could contribute to surgical planning. We developed a semiautomatic presurgical computed tomography angiography (CTA)-based model to measure the renal volume of each RA, validated on postsurgical CTA in patients with HK treated for AAA. Renal parenchyma volume was extracted on both CTAs (Vol_Totpre and Vol_Totpost) after labeling RAs ostia and vascular endpoints by two observers using a semiautomatic model by assigning each renal voxel to the closest vascular ending, obtaining volumes for each vascular territory. Number of RAs number was 4.0 ± 1.4 (mean ± standard deviation (SD)), Vol_Totpre 360 ± 76.5 cm3; kidney volume loss at surgery (KVLS) (Vol_Totpre minus Vol_Totpost) 51.9 ± 35.4 cm3; percentage of kidney loss 15.2 ± 11.6%. KVLS and predicted kidney volume loss on preoperative CTA (PKVL) were strongly correlated (r = 0.93; p = 0.023). Interobserver agreement was good (mean bias = 0.000001 ± 1.96 SD of 19.1 cm3). Presurgical semiautomatic segmentation of vascular territories in patients with HK and AAA is feasible. RELEVANCE STATEMENT: This software allowed the preoperative calculation of renal volume perfused by each renal artery in the challenging association of the horseshoe kidney and abdominal aortic aneurism. It helps to determine the feasibility of surgical resection of arteries, thereby improving surgical planning and reducing the risk of postoperative renal function deterioration. KEY POINTS: The association between horseshoe kidney and abdominal aortic aneurism is a challenging condition that may require renal vascular resection. A semiautomatic model measures renal volume perfused by each artery on preoperative computed tomography angiography with high accuracy. Customized use of this tool could improve surgical management by determining which arteries can be safely resected during surgery.

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.

Postoperative Intensive Care Management of Aortic Repair

Vascular surgery patients have multiple comorbidities and are at high risk for perioperative complications. Aortic repair surgery has greatly evolved in recent years, with an increasing predominance of endovascular techniques (EVAR). The incidence of cardiac complications is significantly reduced with endovascular repair, but high-risk patients require postoperative ST-segment monitoring. Open aortic repair may portend a prohibitive risk of respiratory complications that could be a contraindication for surgery. This risk is greatly reduced in the case of an endovascular approach, and general anesthesia should be avoided whenever possible in the case of endovascular repair. Preoperative renal function and postoperative kidney injury are powerful determinants of short- and long-term outcome, so that preoperative risk stratification and secondary prevention are critical tasks. Intraoperative renal protection with selective renal and distal aortic perfusion is essential during open repair. EVAR has lower rates of postoperative renal failure compared to open repair, with approximately half the risk for acute kidney injury (AKI) and one-third of the risk of hemodialysis requirement. Spinal cord ischemia used to be the most distinctive and feared complication of aortic repair. The risk has significantly decreased since the beginning of aortic surgery, with advances in surgical technique and spinal protection protocols, and is lower with endovascular repair. Endovascular repair avoids extensive aortic dissection and aortic cross-clamping and is generally associated with reduced blood loss and less coagulopathy. The intensive care physician must be aware that aortic repair surgery has an impact on every organ system, and the importance of early recognition of organ failure cannot be overemphasized.

PCSK9 and Other Metabolic Targets to Counteract Ischemia/Reperfusion Injury in Acute Myocardial Infarction and Visceral Vascular Surgery

Ischemia/reperfusion (I/R) injury complicates both unpredictable events (myocardial infarction and stroke) as well as surgically-induced ones when transient clampage of major vessels is needed. Although the main cause of damage is attributed to mitochondrial dysfunction and oxidative stress, the use of antioxidant compounds for protection gave poor results when challenged in clinics. More recently, there is an assumption that, in humans, profound metabolic changes may prevail in driving I/R injury. In the present work, we narrowed the field of search to I/R injury in the heart/brain/kidney axis in acute myocardial infarction, major vascular surgery, and to the current practice of protection in both settings; then, to help the definition of novel strategies to be translated clinically, the most promising metabolic targets with their modulatory compounds—when available—and new preclinical strategies against I/R injury are described. The consideration arisen from the broad range of studies we have reviewed will help to define novel therapeutic approaches to ensure mitochondrial protection, when I/R events are predictable, and to cope with I/R injury, when it occurs unexpectedly.

Spinal Cord Ischemia After Thoracoabdominal Aortic Aneurysms Endovascular Repair: From the Italian Multicenter Fenestrated/Branched Endovascular Aneurysm Repair Registry

PURPOSE

The aim of this study is to report an Italian multicenter experience analyzing the incidence and the risk factors associated with spinal cord ischemia (SCI) in a large cohort of thoracoabdominal aortic aneurysms (TAAAs) treated by fenestrated-branched endovascular aneurysm repair (F-/B-EVAR).

MATERIALS AND METHODS

All consecutive patients undergoing F-/B-EVAR in 4 Italian university centers between 2008 and 2019 were prospectively recorded and retrospectively analyzed. Spinal cord ischemia, 30 day/in-hospital adverse events, and mortality were assessed as early outcomes. Risk factors for SCI were determined by multivariable analysis.

RESULTS

A total of 351 patients received F-/B-EVAR for a TAAA. Twenty-eight (8.0%) patients died within 30 postoperative days or during the hospitalization. Regarding SCI, 47 patients (13.4%) developed neurological symptoms related to spinal cord impaired perfusion. Among them, 17 (4.8%) had a major permanent impairment. The multivariable analysis identified that SCI was associated with Crawford extent I to III (odds ratio [OR]: 20.90, p=0.004, 95% confidence interval [CI]=2.69-162.57), and with endovascular procedures performed for ruptured TAAA (OR: 5.74, p=0.010, 95% CI=1.53-21.57). Spinal cord ischemia was also significantly associated with a grade 3 bleeding during the visceral stage (OR: 4.34, p=0.005, 95% CI=1.55-12.16) and a grade 2 renal insufficiency at 30 days (OR: 7.45, p=0.002, 95% CI=2.12-26.18).

CONCLUSION

The present study indicates that SCI is still an open issue after extent I to III TAAA endovascular repair, while its incidence in extent IV TAAA and pararenal/juxtarenal aneurysms is rare. Thoracoabdominal aortic aneurysms extension, urgent TAAA repair for rupture, severe bleeding, and 30 day renal insufficiency have been identified as significant risk factors for SCI. In the presence of such factors, adjunctive strategies may be considered to reduce SCI rates, while in low-risk patients invasive or potentially-risky maneuvers might not be justified.