Covered Endovascular Reconstruction of the Iliac Artery Bifurcation (CERIB).

PURPOSE: The aim of this study was to present the covered endovascular reconstruction of the iliac artery bifurcation (CERIB) technique as a revascularization option for aorto-iliac occlusive disease (AIOD) involving the iliac artery bifurcation. METHODS: This was a retrospective single-center study including all patients undergoing a CERIB procedure from January 2021 until December 2022. Covered endovascular reconstruction of the iliac artery bifurcation procedures were performed percutaneously with bilateral femoral access, excepting cases where simultaneous open femoral artery reconstruction was required due to the extension of peripheral arterial occlusive disease. Standard patient, procedural, and follow-up (FU) data including survival and arterial reinterventions were gathered and analyzed. RESULTS: A total of 13 patients were included (11/13 male, median age=70 [60-76] years). Additional open and/or endovascular procedures included endarterectomy of the femoral bifurcation (n=6), rotational atherectomy (n=2), and 1 axillary artery cutdown for upper limb access (n=1). Median operating time was 2.9 hours (1.5-4.9 hours); median radiation duration and dose were 28.4 (14.3-63.3 minutes) and 4090.6 (384.4-9430.1 cGray/cm2), respectively. The stent grafts used for CERIB were BeGraft peripheral n=31, BeGraft Aortic n=4 and BeGraft peripheral plus n=1 (Bentley InnoMed GmbH, Hechingen, Germany). In 2 patients with prior stenting of the common iliac artery (CIA), only the internal and external iliac arteries (IIA and EIA) were treated in this study, and in 2 cases, additional uncovered stents were required for relining. Technical success was 100%. During a midterm FU (median 18 [4-31] months), 2 patients died from cardiovascular reasons and 1 patient with prior iliac stenting required reinterventions for recurring occlusion. CONCLUSION: Covered endovascular reconstruction of the iliac artery bifurcation is a straightforward option for treating AIOD involving the iliac artery bifurcation that allows preservation of internal iliac artery perfusion and shows good early and midterm results. Prior iliac artery stenting may be a risk factor for early occlusion after CERIB. CLINICAL IMPACT: Aorto-iliac occlusive disease with involvement of the internal iliac artery is encountered regularly in vascular surgical practice, but the internal iliac artery is often not included in the revascularization strategy. The present article will increase the awareness for the relevance of including the internal iliac artery in revascularization strategies and presents CERIB as another method to be added to the armamentarium of (endo-)vascular surgeons and interventionalists.

Rendezvous intervention using combined surgical carotid endarterectomy followed by endovascular thrombectomy in patients with acute tandem occlusions: a proof-of-concept experience at a tertiary care center.

BACKGROUND: Endovascular thrombectomy (EVT) is highly effective in acute stroke patients with intracranial large vessel occlusion (LVO), however, presence of concomitant cervical occlusion of the internal carotid artery (ICA) may limit the endovascular access. This study describes feasibility and efficacy of a surgical carotid access (cutdown) to perform interdisciplinary recanalization therapy including carotid endarterectomy (CEA) followed by EVT for recanalization of intracranial LVO in stroke patients with tandem occlusions. METHODS: We identified stroke patients with tandem occlusions who underwent a combined surgical-endovascular approach over a 5-year period. Surgical cutdown was provided by a cardiovascular surgery team at the angio-suite followed by EVT performed by the neuroradiological team. Demographics, stroke characteristics, treatments including antithrombotic management, procedure times, and clinical follow-up were assessed. RESULTS: Four patients with acute stroke because of tandem occlusions received CEA followed by EVT (two patients after frustrating femoral catheterization, two as first-line approach). Successful recanalization (TICI ≥ 2b) via endovascular thrombectomy was achieved in all patients at a median of 28 min after successful surgical CEA. Intraprocedural complication was observed in one case (25%; i.e. ICA dissection). CONCLUSIONS: This small study provides evidence that a combined interdisciplinary approach of CEA followed by EVT in the angio-suite in acute stroke patients with tandem occlusions is a feasible procedure in patients otherwise not accessible to endovascular recanalizing therapy and, therefore, high likelihood of developing large hemispheric infarction. Prospective data are warranted to identify patients who benefit from this combined approach as first-line therapy.

Infrarenal Remains Infrarenal-EVAR Suitability of Small AAA Is Rarely Compromised despite Morphological Changes during Surveillance.

The aim was to analyze small abdominal aortic aneurysm (AAA) morphology during surveillance with regard to standard endovascular aortic repair (EVAR) suitability. This retrospective single-center study included all patients (n = 52, 48 male, 70 ± 8 years) with asymptomatic AAA ≤ 5.4 cm undergoing ≥2 computed tomography angiography(CTA)/magnetic resonance imaging (MRI) studies (interval: ≥6 months) between 2010 and 2018. Aneurysm diameter, neck quality (shape, length, angulation, thrombus/calcification), aneurysm thrombus, and distal landing zone diameters were compared between first and last CTA/MRI. Resulting treatment plan changes were determined. Neck shortening occurred in 25 AAA (mean rate: 2.0 ± 4.2 mm/year). Neck thrombus, present in 31 patients initially, increased in 16. Average AAA diameters were 47.7 ± 9.3 mm and 56.3 ± 11.6 mm on first and last CTA/MRI, mean aneurysm growth rate was 4.2 mm/year. Aneurysm thrombus was present in 46 patients primarily, increasing in 32. Neck thrombus growth and neck length change, aneurysm thrombus amount and aneurysm growth and aneurysm growth and neck angulation were significantly correlated. A total of 46 (88%) patients underwent open (12/46) or endovascular (34/46) surgery. The planned procedure changed from EVAR to fenestrated EVAR in two patients and from double to triple fenestrated EVAR in one. Thus, standard EVAR suitability was predominantly maintained as the threshold diameter for surgery was reached despite morphological changes. Consecutively, a possibly different pathogenesis of infra- versus suprarenal AAA merits further investigation.

Perioperative and long-term outcome after ascending aortic and arch repair with elephant trunk and open thoracoabdominal aortic aneurysm repair.

OBJECTIVE: To describe the outcome of open thoracoabdominal aortic aneurysm (TAAA) repair following previous aortic arch repair including elephant trunk (ET) or frozen elephant trunk (FET) for acute and chronic pathologies. METHODS: This was a retrospective, observational, multicenter study including 32 patients treated between 2006 and 2019 in two aortic centers using identical surgical protocols. Assessment focused on perioperative and long-term outcome, namely in-hospital morbidity and mortality, as well as procedure-related reintervention rate and aortic-related mortality rate. Kaplan-Meier curves with 95% confidence intervals were used to analyze the overall survival after surgery within the cohort. RESULTS: Thirty-two patients (mean age, 45.0 ± 13.6 years; 20 males [62.5%]) were treated because of acute (34.38% [n = 11]) or chronic (65.62% [n = 21]) aortic pathologies, including residual dissection following acute, symptomatic type A dissection (n = 7) and symptomatic mega aortic syndrome (n = 4), as well as post-dissection TAAA (n = 18) and asymptomatic mega aortic syndrome (n = 3). Twenty-eight patients (87.5%) received type II repair, and 4 patients (12.5%) received type III repair after previous ascending aorta and arch repair including ET/FET. Concomitant infrarenal and iliac vessel repair was performed in 38.7% (n = 12) and 29.4% (n = 10), respectively. The in-hospital mortality rate was 18.75% (n = 6). Spinal cord ischemia occurred in two cases, both after one-stage emergency procedure with one case of permanent paraplegia. Temporary acute kidney injury occurred in 41.94% (n = 13). The estimated 1-year survival rate was 78.1% (95% confidence interval, 63.9%-95.6%), with a median follow-up time of 1.29 years (interquartile range, 0.26-3.88 years). No procedure-related reinterventions and one case of aortic-related mortality, namely sepsis because of graft infection, was observed. CONCLUSIONS: Open TAAA repair following aortic arch repair including ET or FET because of acute or chronic aortic pathologies is associated with a relevant perioperative morbidity and mortality rate. During follow-up, a low aortic-related mortality rate and procedure-related reintervention rate were observed.

Intraoperative contrast-enhanced ultrasound examination for endoleak detection after complex and infrarenal endovascular aortic repair.

OBJECTIVE: The aim of this pilot study was to evaluate intraoperative contrast-enhanced ultrasound (iCEUS) examination for endoleak (EL) detection after complex endovascular aortic repairs (EVAR) in comparison with the standard angiographic completion control. METHODS: Twenty-one patients (16 male; median age, 73 years [range, 54-81 years]) who underwent single-stage EVARs at our center between October 2016 and October 2018 were included prospectively. The procedures comprised fenestrated and/or branched EVAR (n = 14; 66%), infrarenal EVAR (n = 5; 24%), infrarenal EVAR with bilateral iliac side branch implantation (n = 1; 5%), and infrarenal EVAR with occluder implantation into the internal iliac artery (n = 1; 5%). The used endografts included 14 custom made devices (Cook, Australia Pty Ltd, Brisbane, Australia, n = 6; Vascutek Terumo, Glasgow, Scotland, n = 8) and seven standard infrarenal endografts (Medtronic Inc, Santa Rosa, Calif, n = 5; Vascutek Terumo, Glasgow, Scotland, n = 1; Cook, n = 1). All patients underwent an angiographic completion control for EL detection followed by iCEUS examination. The iCEUS examination was performed by the same examiner who was blinded to the angiography result. In addition to the comparison of the angiographic results to iCEUS examination, iCEUS examination was also compared with the computed tomography angiography (CTA) before discharge (median time to CTA, 5 days [range, 1-7 days]). RESULTS: Angiography detected eight type II EL, defining the EL origin in four cases. In addition to detecting all of those eight EL, iCEUS examination revealed eight more type II EL not seen on angiography (P = .002) and allowed a definition of the EL origin in all cases. CTA before discharge showed a persistence of only 5 of the 16 type II EL detected by iCEUS examination (31%, P = .002). CONCLUSIONS: An iCEUS examination can be used as another adjunct to decrease exposure to contrast agent and radiation during EVAR, including complex procedures. A replacement of the completion angiography by iCEUS examination is conceivable for infrarenal EVAR, but also for endovascular type IV or type V repairs. Future studies with larger patient numbers will help to further validate iCEUS examination during complex EVAR.

Management strategies for true and dissecting visceral artery aneurysms.

BACKGROUND: Visceral artery aneurysms (VAA) are rare and the literature regarding management strategies is limited. The study aim was to evaluate our 13-year experience with VAA treatment including conservative, open surgical and endovascular therapy. METHODS: This retrospective single-center study included 37 patients (31 male, median age 70 years [46-79 years]) with true and dissecting VAA treated between January 2006 and December 2018. Indications for invasive therapy were ruptured (N.=1) and symptomatic (N.=8) VAA or asymptomatic VAA>20 mm (N.=15). The decision on the treatment type was made after interdisciplinary (vascular surgeons/radiologists) discussion. RESULTS: The aneurysms affected the celiac trunk (N.=18, 49%), the splenic artery (N.=11, 30%), the superior mesenteric artery (SMA, N.=6, 16%), the hepatic artery (N.=5, 14%) and proximal SMA side branches (N.=2, 5%). Six patients had multiple VAA, one had an intrahepatic artery aneurysm and one had peripheral mesocolic artery aneurysms plus a VAA. 46% of the patients (N.=17) had coexisting aneurysms in other vascular territories. Thirteen patients were managed conservatively (median VAA diameter 15 [14-25] mm), 18 underwent open surgery with venous or prosthetic bypass or interposition graft implantation and 6 were treated by endovascular means (coiling [N.=3] or endograft [N.=3]). Median follow-up (FU) was 21 months (4-123 months). In-hospital mortality was 0%. Median length of hospital stay was 11 days (5-28 days) after surgical and 3 days (2-71 days) after endovascular treatment. Complications included an early type I endoleak, 3 secondary open abdominal surgeries for bleeding/peritonitis after endovascular treatment of a ruptured intrahepatic aneurysm, an asymptomatic aorto-truncal bypass occlusion and aneurysm recurrence after a venous SMA interposition graft. None of the conservatively treated VAA required invasive treatment during FU. CONCLUSIONS: Small (<20 mm) asymptomatic VAA can be managed conservatively. Whenever invasive treatment is indicated, both open and endovascular treatments can be performed with low complication rates. In order to choose the optimal therapeutic approach, anatomical features and patient comorbidities should be considered and, ideally, discussed interdisciplinarily.

Editor's Choice - Outcomes After One Stage Versus Two Stage Open Repair of Type II Thoraco-abdominal Aortic Aneurysms.

OBJECTIVE: This study compared the outcomes of open one stage with open two stage repair of type II thoraco-abdominal aortic aneurysms (TAAA). METHODS: This retrospective study included 94 patients (68 men) with a mean ± SD age of 54.5 ± 14 years who underwent open type II TAAA repair from March 2006 to January 2016. The mean aneurysm diameter was 65 ± 14.4 mm. The median follow up was 42 months (range 12-96). Seventy-six patients received one stage open repair and 18 patients were treated in two steps: 12 received two open procedures (thoracic and abdominal) and six received hybrid repair (one open and one endovascular procedure). This study focused on the comparison of open one stage and open two stage TAAA repair. The median time between the two steps was 31.5 days (range 1-169). RESULTS: In hospital mortality after open one stage repair versus open two stage type II repair was 22.4% versus 0% (odds ratio 7.352, 95% confidence interval [CI] 0.884-959.1]; p = .19). The one year survival rate after one stage repair versus open two stage repair was 74.7% (95% CI 62.7-83.3) versus 90.9% (95% CI 50.8-98.7 [p = .225]). The five year survival rate after one stage repair versus open two stage repair was 53.0% (95% CI 37.2-66.5) versus 90.9% (95% CI 50.8-98.7 [p = .141]). The hazard ratio for survival after one stage repair and after open two stage repair was 4.563 (95% CI 96.9-81.4 [p = .137]). Paraplegia was observed after open one stage repair versus open two stage in 10.5% vs. 8% (p = 1). Acute kidney injury requiring permanent dialysis and myocardial infarction were assessed for after open one stage repair and open two stage and were seen in 3.9% vs. 0% (p = 1) and in 5.3% vs. 0% (p = 1), respectively. CONCLUSION: Open two stage repair may be recommended as a treatment option for type II TAAAs if anatomically feasible, as it has a lower mortality and similar complication rates to one stage repair.

Editor's Choice - Open Thoracic and Thoraco-abdominal Aortic Repair After Prior Endovascular Therapy.

OBJECTIVE: The aim was to present current results of open thoracic and thoraco-abdominal aortic repair as secondary procedure after prior endovascular therapy. METHODS: This was a retrospective cross border single centre study. From 2006 to July 2017 45 open thoracic aortic (TAA) or thoraco-abdominal aortic aneurysm (TAAA) operations were performed on 44 patients (median age 58 [15-80] years) as secondary surgery after previous endovascular therapy comprising TEVAR (n = 38; 86%), EVAR (n = 3; 7%), fenestrated EVAR (n = 1; 2%) and TEVAR plus EVAR (n = 1; 2%). Eleven patients (25%) had had previous open aortic surgery at the secondary surgery site. Indications for TAA(A) repair were Type I endoleak (n = 10; 23%), post-dissection aneurysm progression due to persisting false lumen perfusion (n = 8; 18%), proximal/distal disease progression (n = 16; 36%), device fracture/dislocation (n = 4; 9%), infection (n = 5; 11%), and initial endograft misplacement (n = 1; 2%). The operations included descending thoracic aortic repair (n = 13, 29%), TAAA Type I (n = 4; 9%), Type II (n = 5; 11%), Type III (n = 13; 29%), Type IV (n = 7; 16%), and Type V repair (n = 3; 7%) with simultaneous arch repair in 18% (n = 8). The median time to secondary surgery was 36 (2-168) months. The median follow up was 39 (3-118) months. RESULTS: In hospital mortality was 20% (n = 9) due to intra-operative aneurysm rupture, pneumonia induced sepsis, hemorrhagic cerebellar infarction, mesenteric ischaemia, broncho-esophageal fistula, and multiorgan failure (1/9) as well as haemorrhage (3/9). Estimated survival was 73% at 1 year and 71% overall. The most frequent complications were pneumonia (n = 19; 43%), bleeding requiring revision (n = 11; 25%) and sepsis (n = 14; 32%). Transient dialysis was required in 32% (n = 14), permanent dialysis in 6% (n = 2). Permanent spinal cord deficit (paraparesis) occurred in 6% (n = 2). Estimated freedom from aortic re-intervention was 86%. CONCLUSION: Open TAA(A) repair as a secondary procedure after previous endovascular aortic therapy is an important treatment option even in the endovascular era. It represents a durable treatment that can produce respectable outcomes. Yet the peri-operative morbidity and mortality are relevant and a specialised team and infrastructure are mandatory for these complex procedures. Therefore, centralisation is required.

Editor's Choice - Open Thoracic and Thoraco-abdominal Aortic Repair in Patients with Connective Tissue Disease.

OBJECTIVE/BACKGROUND: The aim is to present current results of open complex aortic repair in patients with connective tissue disease (CTD). METHODS: This was a retrospective cross-border, single centre study. From February 2000 to April 2016 72 aortic operations were performed on 65 patients with CTD (41 male, median age 41 years [range 19-70 years]). Fifty-six patients (86%) underwent at least one previous aortic repair (71 open, four endovascular), including 33 patients (51%) operated before at the site of the procedure reported here. The open procedures, counting eight emergency operations (11%), included aortic arch revision (n = 1; 1%), descending thoracic aortic repair (n = 11; 15%), TAAA type I repair (n = 12; 17%), type II repair (n = 29; 40%), type III repair (n = 12; 17%), and type IV repair (n = 5; 7%). Simultaneous repair of the ascending aorta and/or the aortic arch was performed in two (3%) and eight cases (11%), respectively. Seven patients (10%) underwent staged procedures. Median follow-up was 42 months (0.5-180 months). RESULTS: The in hospital mortality was 14% (n = 9) as a result of haemorrhage (n = 3/9), neurological (n = 3/9), cardiac (n = 2/9), and pulmonary (n = 1/9) complications. Paraplegia and paraparesis occurred in one (2%) and three patients (5%), respectively. Seven patients (11%) required temporary dialysis; none needed permanent dialysis. Major complications were revision surgery for bleeding or haematoma (n = 20/65), sepsis (n = 10/65), myocardial infarction/severe cardiac arrhythmia (n = 2/65), stroke (n = 2/65), as well as multiorgan failure, abdominal compartment syndrome, mesenteric and peripheral ischaemia (all n = 1/65). Multivariate analysis identified an operating time > 7 hours (p = .006) as an independent predictor of increased mortality. Freedom from re-intervention was 85%, 1 year survival was 80%, and overall survival was 75%. CONCLUSION: Open TAA(A) repair is a durable therapy for patients with CTD. Often being performed as revision surgery, it can be associated with relevant risks and should therefore be reserved for specialised centres. Staged procedures and thus reducing operating time, if applicable, should be preferred.

Treatment of blunt thoracic aortic injury in Germany-Assessment of the TraumaRegister DGU®.

PURPOSE: Using the data delivered by the German Trauma Register DGU® from 2002 till 2013, the value of different therapies of blunt thoracic aortic injury (BTAI) in Germany was analyzed. METHODS: Prospectively collected data of patients suffering from BTAI were retrospectively analyzed with focus on the different treatment modalities for grade I-IV injuries. RESULTS: 821 patients suffering from BTAI were identified: 51.6% (424) grade I injury, 35.4% (291) grade II or III injury and 12.9% (106) grade IV injury (77.5% men [44.94 ± 20.6 years]). The main patterns of injury were high- speed accidents and falls (78.0% [n = 640], 21.8% [n = 171] respectively). Significant differences between grade I and grade II/III as well as IV injuries could be assessed for the incidence of cardiopulmonary resuscitation, a Glasgow Coma Scale score below 8 and a systolic blood pressure below 90 mmHg (p-value: <0.001). In the primary admission subgroup, 44.1% (197/447) of the patients received best medical treatment, 55.9% received surgical intervention (250/447): Thereof 37.2% (93/250) received open surgery and 62.8% (147/250) had been treated by endovascular means. Significantly lower 24-h- and in-hospital-mortality rates were encountered after endovascular treatment for all gradings of BTAI (p-value: <0.001). Yet this subgroup of patients showed the lowest incidence of further severe injuries and cardiac arrest. CONCLUSION: Endovascular therapy became the treatment of choice for BTAI in Germany. Patients who have been treated by surgical means showed the highest survival rate, especially endovascular therapy showed a favorable low mortality rate.

Selective renal blood perfusion induces renal tubules injury in a porcine model.

OBJECTIVE: Extracorporeal circulation is routinely used in thoracoabdominal aortic aneurysm repair to preserve blood perfusion. Despite this protective measure, acute and chronic kidney disorders can develop. Therefore, the aim of this study was to establish a new large-animal model to assess the efficacy of selective renal perfusion (SRP) with extracorporeal circulation in a setting of thoracoabdominal aortic aneurysm repair. METHODS: Eighteen pigs underwent a thoracolaparotomy, during with the aorta and renal arteries were exposed. The animals were divided into three cohorts of six pigs each: cohort I--control; cohort II--thoracic aortic clamping with distal aortic perfusion (DAP) using a roller pump; and cohort III--thoracic aortic clamping with DAP plus SRP. Kidney metabolism, kidney injury, and red blood cell damage were measured by oxygen extraction ratio (O2ER), neutrophil gelatinase-associated lipocalin, a marker for acute kidney damage, and serum free hemoglobin. RESULTS: With normal mean arterial blood pressures, flow rates in the renal arteries during perfusion decreased to 75% (group II) with DAP and to 50% (group III) with SRP compared with the control animals (group I; P = .0279 for I vs II; P = .0002 for I vs III). Microcirculation, measured by microspheres, did not differ significantly among the groups. In contrast, O2ER (P = .0021 for I vs III) and neutrophil gelatinase-associated lipocalin (P = .0083 for I vs III) levels were significantly increased in group III, whereas free hemoglobin was increased in groups II and III (P = .0406 for I vs II; P = .0018 for I vs III). CONCLUSIONS: SRP with a roller pump induces kidney tubule injury. Thus, distal aortic and SRP in our model does not provide adequate kidney protection. Furthermore, the perfusion system provokes red blood cell damage with increased free hemoglobin. Hence, the SRP perfusion technique should be revised and tested.

Extracorporeal circulation increases proliferation in the intestinal mucosa in a large animal model.

OBJECTIVE: Extracorporeal circulation induces ischemia/reperfusion injury in the small intestinal wall. One reason for this damage is a perfusion shift from the muscular toward the mucosal layer. This study investigated the effect of this perfusion shift on the small-intestinal apoptosis and proliferation. METHODS: Twenty-eight pigs were randomly assigned to the following cohorts and underwent a thoracolaparotomy and a 1 hour main procedure: cohort I: control; cohort II: thoracic aortic cross-clamping (TAC) without perfusion; cohort III: TAC and distal aortic perfusion (DAP); cohort IV: TAC, DAP, and selective visceral perfusion. The main procedure was followed by 2 hours of reperfusion in all cohorts. Tissue samples were taken during the experiment, stained, and analyzed for apoptosis and proliferation (caspase-3, annexin-V, terminal deoxynucleotide transferase-mediated deoxy uridine triphosphate nick-end labeling, and proliferating cell nuclear antigen). Six animals died unexpectedly during the experiment and were excluded from the analysis. RESULTS: Extensive tissue damage and necrosis was only found in cohort II after the main procedure. In the mucosa, the proliferation was increased in cohort III at the end of the experiment (P = .0157 cohort I vs II). In contrast, the annexin-V/proliferating cell nuclear antigen ratio was significantly higher in cohorts II and IV than in cohorts I and II at the end of the experiment (P = .0034). Furthermore, the caspase-3/annexin-V ratio was increased in all cohorts at the end of the experiment (P = .0015). CONCLUSIONS: Mucosal proliferation is the early repair mechanism of the limited small intestinal ischemia/reperfusion injury after DAP. Furthermore, the extensive surgical trauma shifted the mucosal apoptosis into an advanced state.

Microcirculatory perfusion shift in the gut wall layers induced by extracorporeal circulation.

OBJECTIVE: Extracorporeal circulation (ECC) is regularly applied to maintain organ perfusion during major aortic and cardiovascular surgery. During thoracoabdominal aortic repair, ECC-driven selective visceral arterial perfusion (SVP) results in changed microcirculatory perfusion (shift from the muscularis toward the mucosal small intestinal layer) in conjunction with macrohemodynamic hypoperfusion. The underlying mechanism, however, is unclear. Therefore, the aim of this study was to assess in a porcine model whether ECC itself or the hypoperfusion induced by SVP is responsible for the mucosal/muscular shift in the small intestinal wall. METHODS: A thoracoabdominal aortic approach was performed in 15 healthy pigs divided equally into three groups: group I, control; group II, thoracic aortic cross-clamping with distal aortic perfusion; and group III, thoracic aortic cross-clamping with distal aortic perfusion and SVP. Macrocirculatory and microcirculatory blood flow was assessed by transit time ultrasound volume flow measurement and fluorescent microspheres. In addition, markers for metabolism and intestinal ischemia-reperfusion injury were determined. RESULTS: ECC with a roller pump induced a significant switch from the muscularis and mucosal layer of the small intestine, even with adequate macrocirculation (mucosal/muscular perfusion ratio: group I vs II, P = .005; group I vs III, P = .0018). Furthermore, the oxygen extraction ratio increased significantly in groups II (>30%) and III (>40%) in the beginning of the ECC compared with the control (group I vs II, P = .0037; group I vs III, P = .0062). Lactate concentrations and pH values did not differ between groups I and II; but group III demonstrated a significant shifting toward a lactate-associated acidosis (lactate: group I vs III, P = .0031; pH: group I vs III, P = .0001). CONCLUSIONS: We demonstrated a significant shifting between the small intestinal gut wall layers induced by roller pump-driven ECC. The shift occurs independently of macrohemodynamics, with a significant effect on aerobic metabolism in the gut wall. Consequently, an optimal intestinal perfusion cannot be guaranteed by a roller pump; therefore, perfusion techniques need to be optimized.

The impact of selective visceral perfusion on intestinal macrohemodynamics and microhemodynamics in a porcine model of thoracic aortic cross-clamping.

INTRODUCTION: Despite its presumed effectiveness and clinical use, the physiology of selective visceral perfusion combined with distal aortic perfusion during open thoracoabdominal aortic surgery has not been characterized. Thus, the aim of this study was to establish a translatable model of thoracic aortic-clamping to assess the effect of selective visceral perfusion with added distal aortic perfusion on local intestinal macrohemodynamics and microhemodynamics, intestinal histopathology, and markers of inflammation and intestinal damage. METHODS: A thoracolaparotomy was performed in 15 pigs, and the aorta was exposed, including the origins of celiac trunk and superior mesenteric artery. The animals were divided into three cohorts: control (I), thoracic aortic cross-clamping (II), and thoracic aortic cross-clamping with selective visceral perfusion plus distal aortic perfusion using extracorporeal circulation (III). Macrocirculatory and microcirculatory blood flow was assessed by transit time ultrasound volume flow measurements and fluorescent microspheres. Intestinal ischemia-reperfusion injury was determined by the analysis of perioperative intestinal fatty acid-binding protein (IFABP) and interleukin-8 (IL-8) levels and correlated with histopathologic changes. RESULTS: Severe intestinal tissue injury and an inflammatory response were observed in cohort II compared with cohort III for IL-8 (38.2 vs 3.56 pg/mL; P = .04). The procedure in cohort III resulted in a flow and pressure-associated intestinal hypoperfusion compared with cohort I in the superior mesenteric artery (mean blood pressure, 24.1 ± 10.4 vs 67.2 ± 7.4 mm Hg; P < .0001; mean flow rates: 353.3 ± 133.8 vs 961.7 ± 310.8 mL/min; P < .0001). This was paralleled in cohort III vs cohort I by a significant mucosal injury (IFABP, 713 ± 307.1 vs 170 ± 115.4 pg/mL; P = .014) despite a profound recruitment of intestinal microcirculation (338% ± 206.7% vs 135% ± 123.7%; P = .05). CONCLUSIONS: This study reports a novel large-animal model of thoracic aortic cross-clamping that allows the study of visceral perfusion strategies. However, we demonstrated with IL-8 and IFABP measurements that thoracoabdominal aortic aneurysm surgery with selective visceral perfusion and distal aortic perfusion is superior to the clamp-and-sew technique, even though small intestinal tissue damage cannot be completely avoided by selective visceral perfusion and distal aortic perfusion. In any case, this model seems to be a platform to evaluate and optimize measures for gut wall protection.