Retroperitoneal Compared to Transperitoneal Approach for Open Abdominal Aortic Aneurysm Repair Is Associated with Reduced Systemic Inflammation and Postoperative Morbidity

Abstract

Background In the United Kingdom, the most common surgical approach for repair of open abdominal aortic aneurysms (AAAs) is transperitoneal (TP). However, retroperitoneal (RP) approach is favored in those with more complex vascular anatomy often requiring a cross-clamp on the aorta superior to the renal arteries. This study compared these approaches in patients matched on all major demographic, comorbid, anatomic, and physiological variables. Methods Fifty-seven patients (TP: n = 24; RP: n = 33) unsuitable for endovascular aneurysm repair underwent preoperative cardiopulmonary exercise testing prior to open AAA repair. The surgical approach undertaken was dictated by individual surgeon preference. Postoperative mortality, complications, and length of hospital stay (LoS) were recorded. Patients were further stratified according to infrarenal (IR) or suprarenal/supraceliac (SR/SC) surgical clamping. Systemic inflammation (C-reactive protein) and renal function (serum creatinine and estimated glomerular filtration rate) were recorded. Results Twenty-three (96%) of TP patients only required an IR clamp compared with 12 (36%) in the RP group. Postoperative systemic inflammation was lower in RP patients (p = 0.002 vs. TP) and fewer reported pulmonary/gastrointestinal complications whereas renal impairment was more marked in those receiving SR/SC clamps (p < 0.001 vs. IR clamp). RP patients were defined by lower LoS (p = 0.001), while mid-/long-term mortality was low/comparable with TP, resulting in considerable cost savings. Conclusion Despite the demands of more complicated vascular anatomy, the clinical and economic benefits highlighted by these findings justify the more routine adoption of the RP approach for complex AAA repair.

Myths and methodologies: Cardiopulmonary exercise testing for surgical risk stratification in patients with an abdominal aortic aneurysm; balancing risk over benefit

“…Acute hypertension has also been associated with decreased blood flow to the vasa vasorum, potentially limiting substrate delivery to the media to cause ischaemic weakening of the aortic wall (Heistad et al, 1978). Although basal systemic vascular endothelial dysfunction has been observed in patients with AAA compared with healthy control subjects, confirmed by lower flow-mediated dilatation (Lee et al, 2017), elevated aortic stiffness (van Disseldorp et al, 2019) and systemic OXINOS (Bailey et al, 2006(Bailey et al, , 2022, there are, to the best of our knowledge, no published studies that have determined whether sympathetic outflow and corresponding BP responses, either at rest or during exercise, are augmented as a consequence. On the contrary, the BP response to exercise appears to be normal [i.e., equivalent to agematched controls (Bailey et al, 2018) or when normalized relative to energy expenditure (Myers et al, 2011)].…”

“…use (Mahta et al, 2019). This might simply reflect 'shared' pathogenic pathways characterized by an imbalance in protease/antiprotease activity that predisposes to focal OXINOS and subsequent connective tissue degradation in both alveolar walls (Lomas, 2016) and aneurysmal walls (Bailey et al, 2006(Bailey et al, , 2022. Furthermore, the development of exercise-induced dynamic hyperinflation and sinusoidal swings in intrathoracic pressure to overcome the increased elastic and resistive loads (Boerrigter et al, 2014) could further compound the risk of CPET-induced AAA rupture, highlighting the need for extra vigilance in patients with chronic obstructive pulmonary disease.…”

“…After seminal work in the early 1990s (Older et al, 1993), CPET has become widely adopted as a complementary clinical tool that can detect functional anomalies and long-term sequelae of individualized comorbidities that are 'unmasked' by the increasing systemic O 2 demands of progressive exercise, helping to identify those patients at increased risk of perioperative events during AAA surgery (Grant et al, 2015;, Rose, Davies, Davison et al, 2018. Increased basal O 2 demand is commonly observed during the intra-and postoperative phases of AAA repair (Ciaffoni et al, 2016), with basal metabolic rate elevated as high as three times preoperative values (Older & Smith, 1988;Viale et al, 1991), which might be related to a systemic elevation in oxidative-inflammatory-nitrosative stress (OXINOS), defined by a free radical-mediated amplification of inflammation and concomitant reduction in vascular nitric oxide (NO) bioavailability, endothelial dysfunction and compromised tissue integrity (Bailey et al, 2006(Bailey et al, , 2022. Thus, unlike static measurements historically constrained to single organ function, the multimodal assessment of CRF better reflects the integrated physiological capacity of a patient or their 'resilience' to meet the physiological homeostatic challenge associated with this increased O 2 demand that ultimately allows the AAA patient to survive surgical repair.…”

“…These recommendations are especially relevant for patients with chronic obstructive pulmonary disease, given their elevated (basal) AAA rupture risk (hazard ratio, 1.7; 95% confidence interval, 1.5−1.9), which persists even after adjustment for common risk factors, including documented tobacco use (Mahta et al., 2019 ). This might simply reflect ‘shared’ pathogenic pathways characterized by an imbalance in protease/antiprotease activity that predisposes to focal OXINOS and subsequent connective tissue degradation in both alveolar walls (Lomas, 2016 ) and aneurysmal walls (Bailey et al., 2006 , 2022 ). Furthermore, the development of exercise‐induced dynamic hyperinflation and sinusoidal swings in intrathoracic pressure to overcome the increased elastic and resistive loads (Boerrigter et al., 2014 ) could further compound the risk of CPET‐induced AAA rupture, highlighting the need for extra vigilance in patients with chronic obstructive pulmonary disease.…”