Raising Systemic Blood Pressure to Delay Irreversible Intestinal Ischemia in a Swine Model of Proximal Superior Mesenteric ArteryOcclusion.

INTRODUCTION: Acute proximal superior mesenteric artery (SMA) occlusion is highly lethal, and adjuncts are needed to mitigate ischemic injury until definitive therapy. We hypothesized that raising mean arterial pressure (MAP) >90 mmHg with norepinephrine may delay irreversible bowel ischemia by increasing gastroduodenal artery (GDA) flow despite possible pressor-induced vasospasm. METHODS: 12 anesthetized swine underwent laparotomy, GDA flow probe placement, and proximal SMA exposure and clamping. Animals were randomized between conventional therapy (CT) versus targeted MAP >90 mmHg (MAP push; MP) where norepinephrine was titrated after 45 min of SMA occlusion. Animals were followed until bowel death or 4 h. Kaplan-Meier bowel survival, mean normalized GDA flow, and histology were compared. RESULTS: 12 swine (mean 57.8 ± 7.6 kgs) were included, six per group. Baseline weight, HR, MAP and GDA flows were not different. Within 5 min following SMA clamping, all 12 animals had an increase in MAP without other intervention from 81.7 to 105.5 mmHg (29.1%, P < 0.01) with a concomitant 74.9% increase in GDA flow as compared to baseline (P < 0.01). Beyond 45 min postclamp, MAP was greater in the MP group as intended, as were GDA flows. Median time to irreversibly ischemic bowel was 31% longer for MAP push animals (CT: 178 versus MP: 233 min, P = 0.006), Hazard Ratio of CT 8.85 (95% CI: 1.86-42.06); 3/6 MP animals versus 0/6 CT animals with bowel survived to predetermined end point. CONCLUSIONS: In this swine model of acute complete proximal SMA occlusion, increasing MAP >90 mmHg with norepinephrine was associated with an increase in macrovascular blood flow through the GDA and bowel survival. Norepinephrine was not associated with worse bowel survival and a MAP push may increase the time window where ischemic bowel can be salvaged.

Luminal Delivery of Pectin-Modified Oxygen Microbubbles Mitigates Rodent Experimental Intestinal Ischemia.

INTRODUCTION: Ischemic gut injury is common in the intensive care unit, impairs gut barrier function, and contributes to multiorgan dysfunction. One novel intervention to mitigate ischemic gut injury is the direct luminal delivery of oxygen microbubbles (OMB). Formulations of OMB can be modified to control the rate of oxygen delivery. This project examined whether luminal delivery of pectin-modified OMB (OMBp5) can reduce ischemic gut injury in a rodent model. METHODS: The OMBp5 formulation was adapted to improve delivery of oxygen along the length of small intestine. Adult Sprague-Dawley rats (n = 24) were randomly allocated to three groups: sham-surgery (SS), intestinal ischemia (II), and intestinal ischemia plus luminal delivery of OMBp5 (II + O). Ischemia-reperfusion injury was induced by superior mesenteric artery occlusion for 45 min followed by reperfusion for 30 min. Outcome data included macroscopic score of mucosal injury, the histological score of gut injury, and plasma biomarkers of intestinal injury. RESULTS: Macroscopic, microscopic data, and intestinal injury biomarker results demonstrated minimal intestinal damage in the SS group and constant damage in the II group. II + O group had a significantly improved macroscopic score throughout the gut mucosa (P = 0.04) than the II. The mean histological score of gut injury for the II + O group was significantly improved on the II group (P ≤ 0.01) in the proximal intestine only, within 30 cm of delivery. No differences were observed in plasma biomarkers of intestinal injury following OMBp5 treatment. CONCLUSIONS: This proof-of-concept study has demonstrated that luminal OMBp5 decreases ischemic injury to the proximal small intestine. There is a need to improve oxygen delivery over the full length of the intestine. These findings support further studies with clinically relevant end points, such as systemic inflammation and vital organ dysfunction.

Mesenteric Ischemia after Cardiac Surgery.

BACKGROUND: Mesenteric ischemia (Me-Is) after cardiac surgery is underreported in present literature but has still earned the bad reputation of a dismal prognosis. This study adds clinical outcomes in a large patient cohort. METHODS: Between 2009 and 2019 of the 22,590 patients undergoing cardiac surgery at our facility 106 (0.47%) developed Me-Is postoperatively. Retrospective patient data was analyzed. Additionally, patients were stratified by outcome-survivors and nonsurvivors. RESULTS: Patients were predominantly male (n = 68, 64.2%), mean age was 71.2 ± 9.3 years. Most procedures were elective (n = 85, 80.2%) and comprised of more complex combined procedures (50.9%) and redos (17.9%). Mean EuroSCORE II averaged 10.9 ± 12.2%. Survival at 30 days was 49.1% (n = 52). Clinical baseline and procedural characteristics did not differ significantly between survivors and nonsurvivors. The median postoperative interval until symptom onset was 5 days in both groups. Survivors were more frequently diagnosed by computed tomography and nonsurvivors based on clinical symptoms. Me-Is was predominantly nonocclusive (n = 84, 79.2%). Laparotomy was the main treatment in both groups (n = 45, 78.8% vs. n = 48, 88.9%, p = 0.94). Predictors of mortality were maximum norepinephrine doses (hazard ratio [HR] 8.29, confidence interval [CI] 3.39-20.26, p < 0.0001), lactate levels (HR 1.06, CI 1.03-1.09), and usage of inotropes (HR 2.46, CI 1.41-4.30). CONCLUSION: The prognosis of Me-Is following cardiac surgery is poor-independently from diagnostic or treatment patterns. There exists a significant asymptomatic time period postoperatively, in which pathophysiologic processes seem to cross the Rubicon. After clinical demarcation, the further course can almost no longer be influenced.

Factors that may affect the outcome of acute occlusive mesenteric ischemia. A single-center study.

BACKGROUND: Acute mesenteric ischemia is a rare but lethal disease. Acute occlusive mesenteric ischemia consists of mesenteric artery embolism, mesenteric artery thrombosis, and mesenteric vein thrombosis. This study aimed to investigate the factors that may affect the outcome of acute occlusive mesenteric ischemia. METHODS: Data from acute occlusive mesenteric ischemia patients admitted between May 2016 and May 2022 were reviewed retrospectively. Patients were divided into 2 groups according to whether complications(Clavien‒Dindo ≥ 2) occurred within 6 months of the first admission. Demographics, symptoms, signs, laboratory results, computed tomography angiography features, management and outcomes were analyzed. RESULTS: 59 patients were enrolled in this study. Complications(Clavien‒Dindo ≥ 2) occurred within 6 months of the first admission in 17 patients. Transmural intestinal necrosis, peritonitis, white blood cell count, percentage of neutrophils, percentage of lymphocytes, neutrophil-to-lymphocyte ratio, lactate dehydrogenase, creatine kinase isoenzyme, cardiac troponin I, laparoscopic exploration rate, open embolectomy rate, enterostomy rate, length of necrotic small bowel, length of healthy small bowel, surgical time and intraoperative blood loss differed significantly between groups. Creatine kinase isoenzyme (OR = 1.415, 95% CI: 1.060-1.888) and surgical time (OR = 1.014, 95% CI: 1.001-1.026) were independent risk factors associated with complications(Clavien‒Dindo ≥ 2). CONCLUSIONS: Our analysis suggests that acute occlusive mesenteric ischemia patients with a creatine kinase isoenzyme level greater than 2.22 ng/mL or a surgical time longer than 156 min are more likely to experience complications'(Clavien‒Dindo ≥ 2) occurrence within 6 months of the first admission.

[Surgical strategies and efficacy analysis for aortic dissection complicating intractable mesenteric artery ischemia].

Objective: To explore the surgical strategies and clinical efficacy for aortic dissection combined with refractory superior mesenteric artery (SMA) ischemia. Methods: This is a retrospective case series study. Clinical data of 24 patients with aortic dissection and refractory SMA ischemia admitted to the Department of Vascular Surgery, Zhongshan Hospital, Fudan University from August 2010 to August 2020 were retrospectively collected. Of the 24 patients, 21 were males and 3 were females, with an age of (50.3±9.9) years (range: 44 to 72 years).Among them, 9 cases were Stanford type A aortic dissection, and 15 cases were type B. All patients underwent CT angiography upon admission, and based on imaging characteristics, they were classified into three types. Type Ⅰ: severe stenosis/occlusion of the SMA true lumen only; Type Ⅱ: stenosis of the true lumens in the descending aorta and SMA (isolated type); Type Ⅲ: stenosis of the true lumens in the thoracoabdominal aorta and SMA (continuation type). Surgical procedures, complications, mortality, and reintervention rates were recorded. Results: Among the 24 patients, 17 (70.8%) were classified as Type Ⅰ, 4 (16.7%) as Type Ⅱ, and 3 (12.5%) as Type Ⅲ. Fourteen cases of Type Ⅰ underwent thoracic endovascular aortic repair combined with SMA stent implantation. Additionally, 3 Type Ⅰ and 1 Type Ⅱ patients underwent only SMA reconstruction (with one case of chronic TAAD treated with iliac artery-SMA bypass surgery). Moreover, 3 Type Ⅱ and 3 Type Ⅲ patients underwent descending aorta combined with SMA stent implantation. There were 5 patients (20.8%) who underwent small bowel resection, either in the same sitting or in a staged procedure. During hospitalization, 4 patients died, resulting in a mortality rate of 16.7%. Among these cases, two patients succumbed to severe intestinal ischemia resulting in multiple organ dysfunction syndrome. The follow-up duration was (46±9) months (range: 13 to 72 months). During the follow-up, 2 patients died, unrelated to intestinal ischemia. The 5-year freedom from reintervention survival rate was 86.1%, and the 5-year cumulative survival rate was 82.6%. Conclusions: Patients with aortic dissection and refractory SMA ischemia have a high perioperative mortality. However, implementing appropriate surgical strategies according to different clinical scenarios can reduce mortality and alleviate intestinal ischemia.

[Modern biochemical markers of acute mesenteric ischemia]. / Sovremennye biokhimicheskie markery ostroi mezenterial'noi ishemii.

OBJECTIVE: To analyze modern literature data on biochemical markers of critical mesenteric ischemia. MATERIAL AND METHODS: We analyzed the most promising, highly specific and sensitive biochemical markers of total and segmental intestinal damage following acute mesenteric ischemia. Analysis included domestic and foreign literature data between 2015 and 2023. RESULTS: We identified the most easy-to-use for any hospitals biochemical markers with at least 90% sensitivity and specificity for further practical research. CONCLUSION: Further prospective research will provide a new step in solving the problem of timely diagnosis of acute mesenteric circulatory disorders.

A Systematic Review of Endovascular Repair Outcomes in Atherosclerotic Chronic Mesenteric Ischaemia.

OBJECTIVE: Chronic mesenteric ischaemia (CMI) treatment focuses on symptom relief and prevention of disease progression. Endovascular repair represents the main treatment modality, while data on the associated antiplatelet regimen are scarce. The aim of this meta-analysis was to assess the early and midterm outcomes of endovascular repair in patients with CMI. DATA SOURCES: Randomised controlled trials and observational studies (1990 - 2022) reporting on early and midterm endovascular repair outcomes in patients with atherosclerotic CMI. REVIEW METHODS: The PRISMA guidelines and PICO model were followed. The protocol was registered to PROSPERO (CRD42023401685). Medline, Embase (via Ovid), and Cochrane databases were searched (end date 21 February 2023). The Newcastle-Ottawa Scale was used for risk of bias assessment, and GRADE for evidence quality assessment. Primary outcomes were technical success, 30 day mortality, and symptom relief, assessed using prevalence meta-analysis. The role of dual antiplatelet therapy (DAPT) was investigated using meta-regression analysis. RESULTS: Sixteen retrospective studies (1 224 patients; mean age 69.8 ± 10.6 years; 60.3% female) reporting on 1 368 target vessels (57.8% superior mesenteric arteries) were included. Technical success was 95.0% (95% CI 93 - 97%, p = .28, I2 19%, low certainty), the 30 day mortality rate was 2.0% (95% CI 2 - 4%, p = .93, I2 36%, low certainty), and immediate symptom relief was 87.0% (95% CI 80 - 92%, p < .010, I2 85%, very low certainty). At mean follow up of 28 months, the mortality rate was 15.0% (95% CI 9 - 25%, p = .010, I2 86%, very low certainty), symptom recurrence 25.0% (95% CI 21 - 31%, p < .010, I2 68%, very low certainty) and re-intervention rate 26.0% (95% CI 17 - 37%, p < .010, I2 92%, very low certainty). Single antiplatelet therapy (SAPT) and DAPT performed similarly in the investigated outcomes. CONCLUSION: Endovascular repair for CMI appears to be safe as first line treatment, with a low peri-operative mortality rate and acceptable immediate symptom relief. During midterm follow up, symptom recurrence and need for re-intervention are not uncommon. SAPT appears to be equal to DAPT in post-operative outcomes.

Immediate postoperative parenteral anticoagulant therapy in patients with mesenteric ischemia after intestinal resection: a retrospective cohort study at a single institute.

BACKGROUND: Bowel gangrene represents a major fatal event in acute mesenteric ischemia. Intestinal resection is inevitable in patients with peritonitis and bowel gangrene. This retrospective study aimed to elucidate the benefit of postoperative parenteral anticoagulation in patients with intestinal resection. METHODS: Patients with acute mesenteric ischemia and bowel gangrene were recruited retrospectively between January 2007 and December 2019. All patients underwent bowel resection. They were categorized into two groups: patients without immediate parenteral anticoagulant therapy (Group A) and those with immediate parenteral anticoagulant therapy (Group B). Thirty-day mortality and survival were analyzed. RESULTS: A total of 85 patients were included, with 29 patients in Group A and 56 patients in Group B. Patients in Group B had lower 30-day mortality (16.1%) and a higher 2-year survival rate (45.4%) than patients in Group A (30-day mortality: 51.7%, p = 0.001; 2-year survival rate: 19.0%, p = 0.001). In the 30-day mortality multivariate analysis, patients in Group B had a better outcome (odds ratio = 0.080, 95% confidence interval between 0.011 and 0.605, p = 0.014). Patients in Group B also had a better outcome in the survival multivariate analysis (hazard ratio: 0.435, 95% confidence interval between 0.213 and 0.887, p = 0.022). CONCLUSIONS: Immediate postoperative parenteral anticoagulant therapy improves prognosis in patients with acute mesenteric ischemia treated by intestinal resection. Trial registration This research was retrospectively approved by the Institutional Review Board (IRB) I&II of Taichung Veterans General Hospital (TCVGH-IRB No.CE21256B) on July 28th, 2021. The informed consent waiver was also approved by IRB I&II of Taichung Veterans General Hospital. The Declaration of Helsinki and ICH-GCP guidelines were followed during this study.

Anaesthesia for vascular emergencies - a state of the art review.

In this state-of-the-art review, we discuss the presenting symptoms and management strategies for vascular emergencies. Although vascular emergencies are best treated at a vascular surgical centre, patients may present to any emergency department and may require both immediate management and safe transport to a vascular centre. We describe the surgical and anaesthetic considerations for management of aortic dissection, aortic rupture, carotid endarterectomy, acute limb ischaemia and mesenteric ischaemia. Important issues to consider in aortic dissection are extent of the dissection and surgical need for bypasses in addition to endovascular repair. From an anaesthetist's perspective, aortic dissection requires infrastructure for massive transfusion, smooth management should an endovascular procedure require conversion to an open procedure, haemodynamic manipulation during stent deployment and prevention of spinal cord ischaemia. Principles in management of aortic rupture, whether open or endovascular treatment is chosen, include immediate transfer to a vascular care centre; minimising haemodynamic changes to reduce aortic shear stress; permissive hypotension in the pre-operative period; and initiation of massive transfusion protocol. Carotid endarterectomy for carotid stenosis is managed with general or regional techniques, and anaesthetists must be prepared to manage haemodynamic, neurological and airway issues peri-operatively. Acute limb ischaemia is a result of embolism, thrombosis, dissection or trauma, and may be treated with open repair or embolectomy, under either general or local anaesthesia. Due to hypercoagulability, there may be higher numbers of acutely ischaemic limbs among patients with COVID-19, which is important to consider in the current pandemic. Mesenteric ischaemia is a rare vascular emergency, but it is challenging to diagnose and associated with high morbidity and mortality. Several peri-operative issues are common to all vascular emergencies: acute renal injury; management of transfusion; need for heparinisation and reversal; and challenging postoperative care. Finally, the important development of endovascular techniques for repair in many vascular emergencies has improved care, and the availability of transoesophageal echocardiography has improved monitoring as well as aids in surgical placement of endovascular grafts and for post-procedural evaluation.

Mesenteric Ischemia in a Splenectomized Patient with Auto-Immune Hemolytic Anemia: Case Report.

Mesenteric ischemia is a serious complication that can occur after splenectomy for hemolytic anemia, potentially leading to lifelong intestinal problems such as ischemia and/or portal hypertension. We present the case of a 33-year-old man with a history of autoimmune hemolytic anemia and splenectomy who developed mesenteric ischemia. The patient experienced abdominal pain and diarrhea, and imaging studies revealed mesenteric vein thrombosis. Surgical intervention confirmed the diagnosis. This case significantly contributes to the existing literature by providing insights into the occurrence of mesenteric ischemia in younger individuals with predisposing factors, as well as its clinical presentation, diagnostic challenges, and severity. Moreover, it has implications for the future diagnosis and management of long-term mesenteric ischemia in patients who have undergone splenectomy for hemolytic anemia.

[Stanford Type A Acute Aortic Dissection Complicated with Intestinal Ischemia Preceded by Superior Mesenteric Artery Bypass:Report of a Case].

A 78-year-old male with sudden onset of chest and back pain was transported to our institution by ambulance. Upon arrival at our hospital, he also complained of abdominal pain. Contrast-enhanced computed tomography (CT) revealed the presence of Stanford type A acute aortic dissection complicated with intestinal ischemia;because of the effects of aortic dissection, the superior mesenteric artery 378 Vol.76 No.5(2023-5) (SMA) was obstructed, leading to the complication of intestinal ischemia. An arterial blood gas test showed elevated lactate and metabolic acidosis. We immediately performed resection of the necrotic portion of the intestine and bypass of the common iliac artery to the SMA. Subsequently, after confirmation of the improvement of acidosis, ascending aortic replacement was performed on the same day. Although the patient's condition was complicated by acute kidney injury and pneumonia, he was discharged home on the 55th postoperative day. Acute aortic dissection complicated by intestinal ischemia has a poor prognosis;however, here we reported a life-saving surgical procedure in a patient with this presentation.

Acute mesenteric ischemia - a persistent problem.

Acute mesenteric ischemia is a disease with a relatively low incidence (0,02-0,9% of acute surgical hospitalizations) but a very high mortality rate which can reach up to 100% without early revascularization. Given the above, prompt and accurate diagnosis and subsequent surgical intervention is the cornerstone of treatment and essential to reduce the high mortality rate. Early revascularization can reduce overall mortality by up to 50%. Treatment of acute mesenteric ischemia requires the cooperation of gastrointestinal surgeons, vascular surgeons and interventional radiologists. Thorough clinical examination, contrast computed tomography performed at the initial stage, and the current possibilities of interventional radiology are the keys to improving the results of treatment of acute mesenteric ischemia. The purpose of this paper is to refresh knowledge in the management of acute mesenteric ischemia and summarize the most up-to-date information on the diagnosis and treatment of this disease.

[Computed tomography diagnostics of acute and chronic mesenteric ischemia]. / Komp'yuterno-tomograficheskaya diagnostika ostroi i khronicheskoi mezenterial'noi ishemii.

BACKGRAUND: Chronic mesenteric ischemia is more often accompanied by clinical signs characteristic of colitis. Acute mesenteric ischemia, unlike chronic, is accompanied by nonspecific symptoms and is a serious disease that requires urgent diagnosis. AIMS: The aim of the study was to evaluate the effectiveness of MSCT in the diagnosis of acute and chronic mesenteric ischemia based on our observations. MATERIALS AND METHODS: The retrospective study included 135 patients with abdominalgia and suspected mesenteric ischemia who underwent multiphase CT of the abdominal cavity with intravenous bolus contrast enhancement. Group 1 included 105 patients with mesenteric ischemia; group 2 included 30, without confirmed mesenteric ischemia, with the presence of a symptom of mesenteric ischemia in the form of abdominalgia. RESULTS: We studied 135 patients, including 105 patients with mesenteric ischemia, 59 women and 46 men of average age 60±14.9 years. The acute form of ischemia (58%) was determined 1.5 times more often than the chronic one. Occlusive and nonocclusive acute mesenteric ischemia occurred in equal proportions. Mesenteric arterial thrombosis was the cause of acute mesenteric ischemia in 23% of cases. Mesenteric venous thrombosis was the cause of chronic intestinal ischemia in 61%, in 5% - acute form. Mixed arterial-venous genesis of mesenteric ischemia was determined in 4% against the background of strangulation obstruction. Dunbar syndrome as a cause of chronic intestinal ischemia was diagnosed in 16%. Chronic ischemic enterocolitis accounted for 10% of all cases of mesenteric ischemia and 23% of chronic ischemia. Symptoms and symptom complexes characteristic of the studied series of diseases with acute or chronic mesenteric ischemia were delineated. Sensitivity, specificity and prognostic value of CT with intravenous bolus contrast enhancement in diagnostics of diseases accompanied by mesenteric ischemia reached 100%. CONCLUSIONS: Multiphase CT of the abdominal cavity with bolus contrast enhancement is highly informative in the diagnosis of acute and chronic forms of mesenteric ischemia. Direct CT signs of impaired blood flow in the arteries or veins of the mesentery were indisputable. Indirect signs of mesenteric ischemia were aimed at a thorough analysis of the condition of mesenteric vessels.

[Acute mesenteric ischemia - a 15-year experience of surgical treatment in a multi-field hospital]. / Ostraya arterial'naya mezenterial'naya ishemiya ­ 15-letnii opyt khirurgicheskogo lecheniya v mnogoprofil'nom statsionare.

OBJECTIVE: To evaluate the results of surgical treatment of arterial acute mesenteric ischemia in a single hospital over a 15-year period (from 2007 to 2022). MATERIAL AND METHODS: There were 385 patients with acute occlusion of superior or inferior mesenteric artery over a 15-year period. The causes of acute mesenteric ischemia were thromboembolism of superior mesenteric artery (51%), its thrombosis (43%) and thrombosis of inferior mesenteric artery (6%). Female patients predominated (258 or 67%), while male patients comprised 33% (n=127). Age of patients ranged from 41 to 97 years (mean 74±9). The main diagnostic method for acute intestinal ischemia was contrast-enhanced computed tomography or CT angiography. Intestinal revascularization was performed in 101 patients: 10 patients - open embolectomy or thrombectomy from superior mesenteric artery, 41 patients - endovascular intervention, 50 patients - combined surgery (revascularization with resection of necrotic bowel segments). Isolated resection of necrotic intestines was performed in 176 patients. Exploratory laparotomy was performed in 108 patients with total bowel necrosis. Prevention and treatment of reperfusion and translocation syndrome after successful intestinal revascularization implied extracorporeal hemocorrection for extrarenal indications (veno-venous hemofiltration or veno-venous hemodiafiltration). RESULTS: Overall 15-year mortality rate (385 patients) for acute SMA occlusion was 71% (256 out of 360 patients), postoperative mortality excluding exploratory laparotomies for the same time period - 59%. Mortality rate for inferior mesenteric artery thrombosis was 88%. Routine CT angiography of mesenteric vessels, active and effective early intestinal revascularization (open or endovascular surgery), as well as extracorporeal hemocorrection methods for reperfusion and translocation syndrome reduced mortality rate to 49% over the past 10 years (from 2013 to 2022). Mortality in acute mesenteric ischemia in the first 5 years of this study (from 2007 to 2012) was 64% (p=0.16). The main cause of death was intestinal gangrene with multiple organ failure. Reperfusion syndrome after effective endovascular revascularization complicated by severe pulmonary edema and acute respiratory distress syndrome resulted death in 15% of patients. CONCLUSION: Acute mesenteric ischemia is followed by high mortality rates and extremely poor prognosis. Early diagnosis of acute intestinal ischemia using modern diagnostic methods (CT angiography of mesenteric vessels), effective revascularization of superior mesenteric artery (open, hybrid or endovascular), prevention and treatment of reperfusion and translocation syndrome can improve postoperative outcomes.

Acute Isolated Mesenteric Artery Dissection: Four Year Experience From a French Intestinal Stroke Centre.

OBJECTIVE: This study aimed to report outcomes of patients with symptomatic acute isolated mesenteric artery dissection (IMAD) treated within a French intestinal stroke centre (ISC). METHODS: All patients with symptomatic IMAD referred to the ISC from January 2016 to January 2020 were included prospectively. Patients with aortic dissection and asymptomatic IMAD were not included. The standardised medical protocol included anticoagulation and antiplatelet therapy, gastrointestinal resting, and oral antibiotics. Operations were considered for acute mesenteric ischaemia (AMI). RESULTS: Among the 453 patients admitted to an ISC during the study period, 34 (median age, 53 years [41 - 67]; 82% men) with acute symptomatic IMAD were included. According to the classification of Yun et al., IMADs were reported as follows: type I (n = 7, 20%), type IIa (n = 6, 18%), type IIb (n = 15, 44%), and type III (i.e., complete superior mesenteric artery [SMA] occlusion; n = 6, 18%). Overall, nine (26%) patients had AMI (type I/II, n = 3; type III, n = 6). On initial computerised tomography angiogram, nine (26%) patients had an associated visceral arterial dissection or pseudoaneurysm. All patients with types I/II (n = 28, 82%) followed a favourable clinical course with conservative therapy, with no need for any operation. All patients with type III (n = 6, 18%) underwent urgent laparotomy with SMA revascularisation (open, n = 4; stenting, n = 1) and or bowel resection (early, n = 3; late, n = 1). Rates of intestinal resection and short bowel syndrome were 12% and 8.8%, respectively. After a median follow up of 26 months [18 - 42], recurrence of symptoms occurred in four (12%) patients and aneurysmal change in 14 (41%), with no re-intervention. CONCLUSION: Although IMAD was associated with a high frequency of AMI, a standardised protocol produced a low rate of intestinal resection. Conservative therapy seems appropriate in types I/II patients, whereas urgent SMA revascularisation should aim to avoid intestinal resection or death in type III patients.

Prognostic factors in patients with acute mesenteric ischemia-novel tools for determining patient outcomes.

BACKGROUND: Acute mesenteric ischemia (AMI) is a devastating disease with poor prognosis. Due to the multitude of underlying factors, prediction of outcomes remains poor. We aimed to identify factors governing diagnosis and survival in AMI and develop novel prognostic tools. METHODS: This monocentric retrospective study analyzed patients with suspected AMI undergoing imaging between January 2014 and December 2019. Subgroup analyses were performed for patients with confirmed AMI undergoing surgery. Nomograms were calculated based on multivariable logistic regression models. RESULTS: Five hundred and thirty-nine patients underwent imaging for clinically suspected AMI, with 216 examinations showing radiological indication of AMI. Intestinal necrosis (IN) was confirmed in 125 undergoing surgery, 58 of which survived and 67 died (median 9 days after diagnosis, IQR 22). Increasing age, ASA score, pneumatosis intestinalis, and dilated bowel loops were significantly associated with presence of IN upon radiological suspicion. In contrast, decreased pH, elevated creatinine, radiological atherosclerosis, vascular occlusion (versus non-occlusive AMI), and colonic affection (compared to small bowel ischemia only) were associated with impaired survival in patients undergoing surgery. Based on the identified factors, we developed two nomograms to aid in prediction of IN upon radiological suspicion (C-Index = 0.726) and survival in patients undergoing surgery for IN (C-Index = 0.791). CONCLUSION: As AMI remains a condition with high mortality, we identified factors predicting occurrence of IN with suspected AMI and survival when undergoing surgery for IN. We provide two new tools, which combine these parameters and might prove helpful in treatment of patients with AMI.

The use of fluorescence angiography to assess bowel viability in the acute setting: an international, multi-centre case series.

INTRODUCTION: Assessing bowel viability can be challenging during acute surgical procedures, especially regarding mesenteric ischaemia. Intraoperative fluorescence angiography (FA) may be a valuable tool for the surgeon to determine whether bowel resection is necessary and to define the most appropriate resection margins. The aim of this study is to report on FA use in the acute setting and to judge its impact on intraoperative decision making. MATERIALS AND METHODS: This is a multi-centre, retrospective case series of patients undergoing emergency abdominal surgery between February 2016 and 2021 in three general/colorectal units where intraoperative FA was performed to assess bowel viability. Primary endpoint was change of management after the FA assessment. RESULTS: A total of 93 patients (50 males, 66.6 ± 19.2 years, ASA score ≥ III in 85%) were identified and studied. Initial surgical approach was laparotomy in 66 (71%) patients and laparoscopy in 27 (29% and seven, 26% conversions). The most common aetiologies were mesenteric ischaemia (n = 42, 45%) and adhesional/herniae-related strangulation (n = 41, 44%). In 50 patients a bowel resection was performed. Overall rates of anastomosis after resection, reoperation and 30-day mortality were 48% (n = 24/50, one leak), 12% and 18%, respectively. FA changed management in 27 (29%) patients. In four patients (4% overall), resection was avoided and in 21 (23%) extra bowel length was preserved (median 50 cm of bowel saved, IQR 28-98) although three patients developed further ischaemia. FA prompted extended resection (median of 20 cm, IQR 10-50 extra bowel) in six (6%) patients. CONCLUSION: Intraoperative use of FA impacts surgical decisions regarding bowel resection for intestinal ischaemia, potentially enabling bowel preservation in approximately one out of four patients. Prospective studies are needed to optimize the best use of this technology for this indication and to determine standards for the interpretation of FA images and the potential subsequent need for second-look surgeries.

Hypogastric Artery Flow Interruption is Associated with Increased Mortality After Open Aortic Repair.

BACKGROUND: Potential complications of pelvic flow disruption during aortic aneurysm repair include buttock ischemia and mesenteric ischemia. Unilateral or bilateral hypogastric artery flow interruption, either from atherosclerosis or intentionally to facilitate aneurysm repair, is considered problematic in endovascular repair; however, it has not been well studied in open abdominal aortic aneurysm (AAA) repair (OAR). We sought to examine the effect of interruption of flow to one or both hypogastric arteries on outcomes after OAR. METHODS: The Society for Vascular Surgery Quality Initiative database was queried for all patients undergoing elective open AAA repair between 2003 and 2020. (redundant) Patients with appropriate data on their hypogastric arteries postoperatively were stratified into two groups-patent bilaterally (normal pelvic perfusion, NPP) and unilateral or bilateral occlusion or ligation (compromised pelvic perfusion, CPP). Primary endpoints were 30-day major morbidity (myocardial infarction, respiratory complications, renal injury, and lower extremity or intestinal ischemia) and mortality. RESULTS: During the study period, 9.492 patients underwent elective open AAA repair-860 (9.1%) with compromised pelvic perfusion and 8,632 (90.9%) with patent bilateral hypogastric arteries. The groups had similar cardiac risk factors, including a history of coronary artery disease, prior coronary intervention, and the use of P2Y12 inhibitors and statins. A majority of patients in the CPP cohort had concurrent iliac aneurysms (63.3% vs. 24.8%; P < 0.001). The perioperative mortality was significantly higher in patients with compromised pelvic perfusion (5.5% vs. 3.1%; P < 0.001). Bilateral flow interruption had a trend toward higher perioperative mortality compared to unilateral interruption (7.1% vs. 4.7%; P < 0.147). The CPP group also had increased rates of myocardial injury (6.7% vs. 4.7%; P = 0.012), renal complications (18.9% vs. 15.9%; P = 0.024), leg and bowel ischemia (3.5% vs. 2.1%; P = 0.008; and 5.7% vs. 3.4%; P < 0.001, respectively). On multivariable analysis, CPP was associated with increased perioperative mortality (OR 1.47, CI 1.14-1.88, P = 0.003). On Kaplan-Meier analysis, there was no difference in survival at 2 years postdischarge between the NPP and CPP cohorts (86.1% vs. 87.5%, log-rank P = 0.275). CONCLUSIONS: Compromised pelvic perfusion is associated with increased perioperative complications and higher mortality in patients undergoing OAR. The sequelae of losing pelvic perfusion, in addition to the presence of more complex atherosclerotic and aneurysmal disease resulting in more difficult dissection, likely contribute to these findings. Thus, patients considered for OAR who have occluded hypogastric arteries or aneurysmal involvement of the hypogastric artery preoperatively may be candidates for more conservative management beyond traditional size criteria.

Determinant of outcome in late presenting type A aortic dissection.

BACKGROUND: Early repair is recommended in type A aortic dissection repair, however, this is not often possible. The aim of this study was to assess the time delays, examine the effect of timing and malperfusion on outcomes, and identify other independent risk factors for mortality. METHODS: This was a retrospective study on data collected prospectively. Primary outcome was 30-day mortality. Secondary outcome was adverse postoperative outcomes. All patients who arrived at the hospital with a type A aortic dissection, irrespective of the timing, were included in the study. Univariate as well as multivariate analysis was carried out. RESULTS: A total of 81 patients presented to our institution during the study period. Half the patients got operated within 86 h of symptom onset and 75% were operated within 183 h. With regards to malperfusion, 6 (8.8%) patients had cerebral malperfusion, 10 (14.7%) had features of myocardial ischemia, and 13 (19.1%) had renal malperfusion. One (1.5%) patient had mesenteric ischemia and 9 (13.2%) had limb ischemia. The duration between symptom onset and operative repair was longer in survivors (152 ± 167 vs. 75 ± 102, p = .29). A total of 29 (42.6%) patients presented with features of one or more organ malperfusion and the mortality in these patients was significantly higher at 10 (34.5%) versus 5 (12.5%); p = .04. Multivariable logistic regression identified CPB time as an independent risk factor in our cohort for 30-day mortality (odds ratio: 1.03; 95% confidence interval: 1.007-1.06). CONCLUSION: In cases of predominantly delayed presentation and operative repair, the outcome is significantly influenced by presence of malperfusion. Surgical repair still produces satisfactory outcomes and should be undertaken at the earliest in most cases.