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 in the acute care setting.

ABSTRACT: Mesenteric ischemia is a group of disorders requiring prompt identification, supportive care, and treatment. Chronic mesenteric ischemia can develop into acute mesenteric ischemia, which has high mortality. Acute mesenteric ischemia can be occlusive (caused by arterial embolism, arterial thrombosis, or mesenteric venous thrombosis) or nonocclusive, with treatment depending on the underlying cause.

Prognostic factors after acute mesenteric ischemia: which patients require specific management?

PURPOSE: Diagnosis and treatment of AMI are a real issue for implicating physicians. In the literature, only one AMI stroke center has reported its results so far, with increasing survival rates. Our aim was to analyze acute mesenteric ischemia (AMI) related mortality and predictive factors, in a single academic center, before creating a dedicated intestinal stroke center. METHODS: All the patients with an AMI, between January 2015 and December 2020, were retrospectively included. They were divided into 2 groups according to the early mortality: death during the first 30 days and alive. The 2 groups were compared. RESULTS: 173 patients (57% of men), were included, with a mean age of 68 ± 16 years. Overall mortality rate was 61%. Mortality occurred within the first 30 days in 78% of dead cases. Dead patients were significantly older, more frequently admitted from intensive care, with more serious clinical, laboratory and radiological characteristics. We have identified 3 protective factors - history of abdominal surgery (Odd Ratio = 0.1; 95%CI = 0.01-0.8, p = 0.03), medical management with curative anticoagulation (OR = 0.09; 95%CI = 0.02-0.5, p = 0.004) and/or antiplatelets (OR = 0.04; 95%CI = 0.006-0.3, p = 0.001)-, and 2 predictive factors of mortality - age > 70 years (OR = 7; 95%CI = 1.4-37, p = 0.02) and previous history of coronaropathy (OR = 13; 95%CI = 1.7-93, p = 0.01). CONCLUSIONS: AMI is a severe disease with high morbidity and mortality rates. Even if its diagnosis is still difficult because of non-specific presentation, its therapeutic management needs to be changed in order to improve survival rates, particularly in patients older than 70 years with history of coronaropathy. Developing a dedicated organization would improve the diagnosis and the management of patients with AMI.

Mortality and Delays of Management of Acute Mesenteric Ischemia: The Need of a Dedicated Program.

BACKGROUND: To study the mortality and delays of management of patients with acute mesenteric ischemia (AMI) admitted to the emergency department of a tertiary hospital and identify risk factors for 1-month mortality. METHODS: A single-center and retrospective study including all consecutive patients treated for AMI from January 2008 to December 2018 was conducted. Short- and medium-term survival was studied with a Kaplan-Meier analysis. Delays before diagnosis and surgical intervention were collected. To determine factors associated with mortality at 1 month postoperatively, univariate and multivariate analyzes were performed. RESULTS: The survival rate of the 67 included patients was 55.22% at 1 month and 37.31% at 1 year. In-hospital mortality was 50.74%. The average delay between admission and diagnosis was 4.83 ± 5.03 hr (95% confidence interval [CI], 3.60-6.05), and the delay between admission and surgical treatment was 10.64 ± 8.80 hr (95% CI, 8.49-12.79). The independent variables associated with an increased mortality at 1 month postoperatively in the univariate analysis were age >65 years old (odds ratio [OR] = 3.52; P = 0.046), lactate >3.31 mmol/l at admission (H0) (OR = 7.38; P < 0.001), lactate >3.32 mmol/l on day 1 (H24) (OR = 5.60; P = 0.002), creatinine >95.9 µmol/l at H0 (OR = 4.66; P = 0.004), aspartate aminotransferase (AST) >59 U/l at H0 (OR = 3.55; P = 0.017), and having hypertension as comorbidity (OR = 9.32; P = 0.040). Early curative anticoagulation (z = -2.4; P = 0.016) was an independent protective factor for mortality, and lactate >3.31 mmol/l at H0 (z = 2.62; P = 0.009) was an independent predictor factor of mortality at 1 month postoperatively in the multivariate analysis. CONCLUSION: AMI remains a serious and lethal condition with delays of surgical management remaining too long due to a lack of a dedicated therapeutic protocol allowing an early diagnosis.

Microcatheter-Directed Thrombolysis Using Recombinant Tissue Plasminogen Activator for the Treatment of Acute Superior Mesenteric Artery Embolism: A Case Report.

Background: Acute mesenteric ischemia (AMI) is a life-threatening condition, and in 50% of patients, AMI is caused by acute superior mesenteric artery (SMA) embolism. Endovascular treatment is increasingly being considered the primary modality in selected cases. Many studies have reported that percutaneous aspiration embolectomy using a guiding catheter and thrombolysis with recombinant tissue plasminogen activator (rtPA) are effective in treating SMA embolism. However, no reports on treating SMA embolism using rtPA administered via a microcatheter exist. Case presentation: A 64-year-old man with underlying atrial fibrillation presented with acute SMA embolism revealed using computed tomography (CT). rtPA (total 3 mg) was carefully administered into the occluded SMA through a microcatheter. No complications occurred, and complete revascularization of the SMA was revealed on follow-up CT. Conclusions: Compared with previous reports, this case report reveals that successful revascularization can be achieved using rtPA administered via a microcatheter, with a low dose of rtPA and a short duration of thrombolysis.

TIPS for Adults Without Cirrhosis With Chronic Mesenteric Venous Thrombosis and EHPVO Refractory to Standard-of-Care Therapy.

BACKGROUND AND AIMS: Extrahepatic portal vein occlusion (EHPVO) from portal vein thrombosis is a rare condition associated with substantial morbidity and mortality. The purpose of this study is to investigate the efficacy of transjugular intrahepatic portosystemic shunts (TIPS) for the treatment of chronic EHPVO, cavernomatosis, and mesenteric venous thrombosis in adults without cirrhosis who are refractory to standard-of-care therapy. APPROACH AND RESULTS: Thirty-nine patients with chronic EHPVO received TIPS. Laboratory parameters and follow-up were assessed at 1, 3, 6, 12, and 24 months, and every 6 months thereafter. Two hepatologists adjudicated symptom improvement attributable to mesenteric thrombosis and EHPVO before/after TIPS. Kaplan-Meier was used to assess primary and overall TIPS patency, assessing procedural success. Adverse events, radiation exposure, hospital length-of-stay and patency were recorded. Cavernoma was present in 100%, with TIPS being successful in all cases using splenic, mesenteric, and transhepatic approaches. Symptom improvement was noted in 26 of 30 (87%) at 6-month follow-up. Twelve patients (31%) experienced TIPS thrombosis. There were no significant long-term laboratory adverse events or deaths. At 36 months, freedom from primary TIPS thrombosis was 63%; following secondary interventions, overall patency was increased to 81%. CONCLUSIONS: TIPS in chronic, noncirrhotic EHPVO with cavernomas and mesenteric venous thrombosis is technically feasible and does not adversely affect liver function. Most patients demonstrate subjective and objective benefit from TIPS. Improvement in patency rates are needed with proper timing of adjuvant anticoagulation.

Contemporary management of acute and chronic mesenteric ischemia: 10-year experience from a multihospital healthcare system.

OBJECTIVE: Endovascular and hybrid methods have been increasingly used to treat mesenteric ischemia. However, the long-term outcomes and risk of symptom recurrence remain unknown. The objective of the present study was to define the predictors of postoperative morbidity, mortality, and patency loss for acute mesenteric ischemia (AMI) and chronic mesenteric ischemia (CMI). METHODS: The inpatient and follow-up records for all patients who had undergone revascularization for AMI and CMI from 2010 to 2020 at a multicenter hospital system were reviewed. Patency and mortality were evaluated with Cox regression, visualized with Kaplan-Meier curves, and compared using log-rank testing. Patency was further evaluated using Fine-Gray regression with death as a competing risk. The postoperative major adverse events (MAE) and 30-day mortality were evaluated with logistic regression. RESULTS: A total of 407 patients were included, 148 with AMI and 259 with CMI. For the AMI group, the 30-day mortality was 31%. Open surgery was associated with lower rates of bowel resection (odds ratio [OR], 0.23; 95% confidence interval [CI], 0.13-0.61). The etiology of AMI also did not change the outcomes (OR, 1.30; 95% CI, 0.77-2.19). Adjusted analyses indicated that a history of diabetes (OR, 2.77; 95% CI, 1.37-5.61) and sepsis on presentation (OR, 2.32; 95% CI, 1.18-4.58) were independently associated with an increased risk of 30-day MAE. In the CMI group, open surgery and chronic kidney disease were associated with a higher incidence of MAE (OR, 3.03; 95% CI, 1.14-8.05; OR, 2.37; 95% CI, 1.31-4.31). In contrast, chronic kidney disease (OR, 3.02; 95% CI, 1.10-8.37) and inpatient status before revascularization (OR, 2.78; 95% CI, 1.01-7.61) were associated with increased 30-day mortality. For the CMI group, the endovascular cohort had experienced greater rates of symptom recurrence (29% vs 13%) with a faster onset (endovascular, 64 days; vs bypass, 338 days). CONCLUSIONS: AMI remains a morbid disease despite the evolving revascularization techniques. An open approach should remain the reference standard because it reduces the likelihood of bowel resection. For CMI, endovascular interventions have improved the postoperative morbidity but have also resulted in early symptom recurrence and reintervention. An endovascular-first approach should be the standard of care for CMI with close surveillance.

Endovascular Revascularization as Primary Treatment for Acute Embolic Mesenteric Ischemia: Stent Thrombectomy plus Aspiration versus Aspiration Alone.

PURPOSE: To investigate the outcomes of stent thrombectomy combined with aspiration versus aspiration alone in acute mesenteric ischemia (AMI). MATERIALS AND METHODS: This was a single-center, retrospective cohort study. Between May 1, 2012, and January 1, 2021, 41 patients (mean age, 73.8 years ± 7.9) with AMI who underwent stent thrombectomy plus aspiration (Group 1, n = 14) or aspiration alone (Group 2, n = 27) were included. The treatment regimens and clinical and follow-up outcomes of the patients were reviewed and analyzed. Group differences were compared using a χ2 test, Fisher exact test, independent t test, or Mann-Whitney U test. The cumulative survival rate was calculated using a Kaplan-Meier curve. RESULTS: The overall clinical success rate was 78.0% (32/41), and no significant differences were found between Group 1 and Group 2 (78.6% vs 77.8%, P = 1.00). Compared with Group 2, Group 1 was associated with a higher complete clearance rate (44.4% vs 78.6%, P = .04), less adjunctive local thrombolysis (48.1% vs 14.3%, P = .03), and a shorter length of hospital stay (10.7 days ± 9.0 vs 5.7 days ± 4.7, P = .03). The estimated survival rates at 1 month, 3 months, 6 months, 1 year, and 2 years were 73.2%, 72.5%, 71.4%, 65.3%, and 59.8%, respectively. No significant difference was found in the survival rate between the groups (log-rank test, P = .96). The recurrence rates for Group 1 and Group 2 were 8.3% (1/12) and 4.0% (1/25), respectively. CONCLUSIONS: Compared with aspiration alone, aspiration combined with stent thrombectomy showed a higher complete clearance rate, reduced adjunctive thrombolysis, and a shorter length of hospital stay.

A systematic review and meta-analysis on endovascular treatment as an attractive alternative for acute superior mesenteric venous thrombosis.

OBJECTIVE: This systematic review and meta-analysis evaluated the published data on the efficacy and safety of therapies for superior mesenteric venous thrombosis (SMVT), aiming to provide a reference and set of recommendations for clinical treatment. METHODS: Relevant databases were searched for studies published from 2000 to June 2020 on SMVT treated with conservative treatment, surgical treatment, or endovascular approach. Different treatment types were grouped for analysis and comparison, and odds ratios with corresponding 95% confidence intervals were calculated. The outcomes were pooled using meta-analytic methods and presented by forest plots. RESULTS: Eighteen articles, including eight on SMVT patients treated with endovascular therapies, were enrolled. The treatment effectiveness was compared between different groups according to the change of symptoms, the occurrence of complications, and mortality as well. The conservative treatment group had better efficacy compared to the surgery group (89.0% vs. 78.6%, P <0.05), and the one-year survival rate was also higher (94.4% vs. 80.0%, P >0.05), but without statistical significance. As for endovascular treatment, the effectiveness was significantly higher than the surgery group (94.8% vs. 75.2%, P <0.05), and the conservative treatment group as well (93.3% vs. 86.3%, P >0.05), which still requires further research for the lack of statistical significance. CONCLUSIONS: Present findings indicate that anticoagulation, as conservative treatment should be the preferred clinical option in the clinic for SMVT, due to its better curative effect compared to other treatment options, including lower mortality, fewer complications, and better prognosis. Moreover, endovascular treatment is a feasible and promising approach that is worth in-depth research, for it is less invasive than surgery and has relatively better effectiveness, thus can provide an alternative option for SMVT treatment and may be considered as a reliable method in clinical.

Outcomes of different acute mesenteric ischemia therapies in the last 20 years: A meta-analysis and systematic review.

OBJECTIVE: Acute mesenteric ischemia is a disease with high morbidity and mortality, and it is traditionally treated with open surgery. Endovascular therapy and hybrid techniques are alternative treatments that are also currently available. We performed a meta-analysis to evaluate the outcomes of the different treatment approaches in the last 20 years. METHODS: Studies on acute mesenteric ischemia that were indexed in PubMed, Embase, and MEDLINE databases (from January 1, 2000, to April 1, 2021) were reviewed. All related retrospective observational studies and case series were included. A random-effects model was used to calculate pooled estimates, and the results were reported as proportions and 95% confidence intervals (CIs). RESULTS: In our study, a total of 2369 patients (in 39 studies) underwent endovascular, open surgery, or retrograde open mesenteric stenting. The pooled mortality estimates for open surgery, endovascular therapy, and retrograde open mesenteric stenting were 40% (95% CI, 0.33-0.47; I2 = 84%), 26% (95% CI, 0.19-0.33; I2 = 33%), and 32% (95% CI, 0.21-0.44; I2 = 26%), respectively. CONCLUSIONS: The mortality associated with open surgical treatment, endovascular therapy, and retrograde open mesenteric stenting tend to be similar in the last 20 years.

Mesenteric Ischemia in a Patient with Essential Thrombocythemia: Does COVID-19 Play Any Role? A Case Report and Overview of the Literature.

INTRODUCTION: Chronic mesenteric ischemia is a rare entity with non-specific symptomatology; combined with rare etiologies, it could lead to unwarranted surgical indication. CASE REPORT: We report the case of an 85-year-old woman, with a history of hypertension, persistent thrombocytosis, atherosclerosis, and recent minor COVID-19 infection, presenting to the hospital with postprandial abdominal pain and nonspecific clinical examination findings; upon abdominal CT, superior mesenteric artery circumferential thrombosis was revealed. A bone marrow biopsy was performed due to suspected essential thrombocythemia, confirming the diagnosis. An endovascular approach was chosen as therapy option and a stent was placed in the occluded area. Dual antiplatelet and cytoreductive therapies were initiated after the intervention. Clinical course was excellent, with no residual stenosis 1 month after stenting. CONCLUSIONS: The therapeutic strategy in elderly patients with exacerbated chronic mesenteric ischemia requires an interdisciplinary approach in solving both the exacerbation and the underlying conditions in order to prevent further thrombotic events. Although the patient presented a thrombotic state, other specific risk factors such as COVID-19 related-coagulopathy and essential thrombocythemia should be considered.

The impact of endovascular treatment on clinical outcomes of stable symptomatic patients with spontaneous superior mesenteric artery dissection.

OBJECTIVE: To evaluate the efficacy and clinical outcomes of endovascular treatment for superior mesenteric artery dissection (SMAD) and its effect on superior mesenteric artery (SMA) remodeling compared with medical management alone after successful initial medical management. METHODS: In this retrospective analysis, all patients with spontaneous SMAD at a single institution were identified from March 2007 to August 2019. The primary outcomes were freedom from major adverse events (MAEs, a composite of dissection-related death, the recurrence of mesenteric ischemia symptoms, and a requirement for intervention). The secondary outcomes were morphologic remodeling of the dissections and stenosis or occlusion of the SMA. RESULTS: A total of 94 patients with SMAD who underwent successful initial medical management (91 males; mean age, 50.4 ± 6.3 years) were enrolled in the study. Fifty-seven (60.6%) received medical management alone, and 37 (39.4%) underwent endovascular repair after initial medical management. In the endovascular group, the technical success rate was 86.5% (32 of 37). During a mean follow-up period of 33.6 ± 26.2 months (range, 1-120 months), nine (9.6%) patients experienced a recurrence of abdominal pain, and six had additional interventions for SMAD. The patients in the endovascular group showed more complete or partial remodeling (22 [81.1%] vs 24 [44.4%]; P < .0001) or unchanged dissections (5 [13.5%] vs 23 [42.6%]; P = .0001) than those in the conservative group. Survival analysis showed that the estimated MAE-free survival rates were 95.6%, 88.9%, and 85.4% at 1, 3, and 5 years, respectively. There was a higher freedom from SMA stenosis or occlusion in the endovascular group (log rank P = .046). CONCLUSIONS: Endovascular treatment and medical management alone result in similar MAE-free survival for patients with SMAD after successful initial medical management. Moreover, endovascular therapy is associated with a higher complete remodeling rate and greater freedom from SMA stenosis or occlusion.

Midterm results after covered stenting of the superior mesenteric artery.

OBJECTIVE: Despite the continuing controversy of covered stents (CS) vs bare metal stents, the use of CS in mesenteric occlusive disease (MOD) has been recommended by expert centers. The aim of this study was to report midterm results with CS of the superior mesenteric artery. METHODS: Between January 2014 and October 2019, patients with MOD with a severe atheromatous stenosis or occlusion of the superior mesenteric artery treated by mesenteric CS were included. Clinical presentation included both acute mesenteric ischemia (AMI), chronic mesenteric ischemia, and asymptomatic patients planned for major surgery. Demographics, procedure details, and follow-up data were prospectively collected and retrospectively reviewed. Study end points included primary patency, primary assisted patency, and secondary patency. RESULTS: During the study period, 86 patients (mean age, 70 ± 9 years; 57% males) were included. Clinical presentation was AMI (n = 42 [49%]), chronic mesenteric ischemia (n = 31 [36%]), and asymptomatic (n = 13 [15%]). The technical success rate was 97%. A total of 96 stents were implanted, including 86 proximal CS (Advanta V12, n = 73; Lifestream, n = 13). The mean length and mean diameter of the CS were 31.5 ± 6.3 mm and 6.9 ± 0.5 mm, respectively. Additional distal bare metal stents were used in 10 patients (12%) to overcome a kinking (n = 9) or a dissection (n = 1) downstream of the CS. All postoperative deaths occurred in patients with AMI (n = 11, 13%). During a median follow-up of 15.6 months (95% confidence interval [CI], 15.6 ± 3.6 months), 12 patients (14%) underwent reinterventions for either stent misplacement (n = 3), stent recoil (n = 3), stent thrombosis (n = 2), de novo stenosis at the distal edge of the CS (n = 2), or gastric ischemia (n = 1). At 1 year, overall the primary patency, primary assisted patency, and secondary patency rates were 83% (95% CI, 83% ± 9%), 99% (95% CI, 99% ± 3%), and 99% (95% CI, 99% ± 3%), respectively. At 2 years, the overall primary patency, primary assisted patency, and secondary patency rates were 76% (95% CI, 76% ± 13%), 95% (95% CI, 95% ± 8%) and 95% (95% CI, 95% ± 8%), respectively. CONCLUSIONS: Mesenteric CS provide very satisfactory midterm results in patients with MOD, with an excellent primary assisted patency rate at 2 years, at the price of a significant reintervention rate.

A clinical approach to acute mesenteric ischemia.

PURPOSE OF REVIEW: To summarize current evidence on acute mesenteric ischemia (AMI) in critically ill patients, addressing pathophysiology, definition, diagnosis and management. RECENT FINDINGS: A few recent studies showed that a multidiscipliary approach in specialized centers can improve the outcome of AMI. Such approach incorporates current knowledge in pathophysiology, early diagnosis with triphasic computed tomography (CT)-angiography, immediate endovascular or surgical restoration of mesenteric perfusion, and damage control surgery if transmural bowel infarction is present. No specific biomarkers are available to detect early mucosal injury in clinical setting. Nonocclusive mesenteric ischemia presents particular challenges, as the diagnosis based on CT-findings as well as vascular management is more difficult; some recent evidence suggests a possible role of potentially treatable stenosis of superior mesenteric artery and beneficial effect of vasodilator therapy (intravenous or local intra-arterial). Medical management of AMI is supportive, including aiming of euvolemia and balanced systemic oxygen demand/delivery. Enteral nutrition should be withheld during ongoing ischemia-reperfusion injury and be started at low rate after revascularization of the (remaining) bowel is convincingly achieved. SUMMARY: Clinical suspicion leading to tri-phasic CT-angiography is a mainstay for diagnosis. Diagnosis of nonocclusive mesenteric ischemia and early intestinal injury remains challenging. Multidisciplinary team effort may improve the outcome of AMI.

Endovascular Treatment of Chronic and Acute on Chronic Mesenteric Ischaemia: Results From a National Cohort of 245 Cases.

OBJECTIVE: Endovascular treatment of chronic mesenteric ischaemia (CMI) is linked to low early morbidity and mortality but a higher risk of recurrence than open repair. Mid and long term outcomes after endovascular treatment remain to be proven in larger series. The aim of this study was to assess short and mid term outcome after first line endovascular revascularisation of CMI and acute on chronic mesenteric ischaemia (AoCMI). METHODS: This was a prospective population and registry based cohort study supplemented by a retrospective review of medical records and imaging files. A national cohort was created based on data extracted from the Danish National Registry for Vascular Surgery (Karbase) for all patients treated endovascularly for CMI or AoCMI between 2011 and 2015 in Denmark. Survival data, bowel resection, complications, re-intervention rate, and improvement of clinical symptoms were analysed, as were potential risk factors. RESULTS: In total, 245 patients had an endovascular intervention for CMI (n = 178; 72.6%) and AoCMI (n = 67; 27.3%). One and three year survival estimates were 85% (95% confidence interval [CI] 79 - 90) and 74% (95% CI 67 - 80) in the CMI-group, and 67% (95% CI 54 - 77) and 54% (95% CI 41 - 65) in the AoCMI group. The hazard ratio for death was 1.89 (95% CI 1.23 - 2.9) for AoCMI, relative to patients with CMI. Superior mesenteric artery (SMA) stenosis, rather then occlusion, significantly increased the success of SMA recanalisation: OR 19.4 (95% CI 6.2 - 61.4) and 9.3 (95% CI 1.6 - 53.6) in the CMI and AoCMI groups, respectively. The proportion of patients reporting clinical improvement was 71% (n = 127) in the CMI group and 59% (n = 39) in the AoCMI group. Five patients (3%) in the CMI and 30 (45%) in the AoCMI groups underwent bowel resection (p < .001), and the overall length of hospital stay (LoS) was a median of two days (interquartile range [IQR] 1 - 3 days) in the CMI group and seven days (IQR 3 - 23 days) in the AoCMI group. Within the first year, re-intervention was performed in 14 patients (5.7%). CONCLUSION: First line endovascular treatment of CMI carries a three year mortality rate of 25%, and low risk of re-occurrence of symptomatic ischaemia. Relative to CMI, patients suffering AoCMI have significantly higher morbidity and mortality, more bowel resections, and longer LoS.

Transcollateral Recanalization of an Occluded Superior Mesenteric Artery.

OBJECTIVE: To report the technique of transcollateral retrograde recanalization of a superior mesenteric artery flush occlusion. METHODS: The technique of a patient undergoing transcollateral retrograde recanalization for acute symptomatic superior mesenteric artery flush occlusion was reviewed and presented. Other adjunctive methods to facilitate the endovascular treatment of the superior mesenteric artery total occlusion lesion were also compared and discussed. RESULTS: The patient was a 47-year-old woman, acute onset of symptomatic chronic mesenteric ischemia with flush occlusion of the superior mesenteric artery which was unable to be revascularized in a routine operation. A collateral was found to connect celiac artery and superior mesenteric artery (gastroduodenal arch). The guidewire was retrograde crossed the occluded lesion via this collateral and recaptured by the catheter from the same single brachial sheath followed by balloon angioplasty and stent implantation. The patient recovered well and the symptoms completely disappeared after the procedure. CONCLUSION: The technique of retrograde recanalization through collateral pathway is an applicable alternative option for patients with superior mesenteric artery flush occlusion who have failed attempts by conventional antegrade approaches.

Defining Duplex Ultrasound Criteria for In-Stent Restenosis of the Superior Mesenteric Artery.

BACKGROUND: This study sought to define duplex ultrasound (DUS) velocity criteria predicting ≥70% stenosis in superior mesenteric artery (SMA) stents by correlating in-stent peak systolic velocity (PSV) with computed tomographic angiography (CTA) measurements of percent stenosis. METHODS: A retrospective review of 109 patients undergoing SMA stenting between 2003 and 2018 was conducted at a single institution. Thirty-seven surveillance duplex ultrasound studies were found to have a CTA performed within 30 days of study completion. Bare metal (n = 20) and covered stents (n = 17) were included. Velocities were paired to in-stent restenosis (ISR) measured by mean vessel diameter reduction on SMA centerline reconstructions from CTA. Receiver operating characteristic (ROC) curves was generated and logistic regression models for ≥70% ISR probability were used to define velocity criteria in the stented SMA. RESULTS: At a PSV of 300 cm/sec, the sensitivity is 100% and specificity 80% for a ≥70% in-stent SMA stenosis. At a PSV of 400 cm/sec, the sensitivity and positive predictive value (PPV) is 63% and the specificity and negative predictive value (NPV) is 90%. A PSV of 450 cm/sec was consistent with the highest specificity (100%) and PPV (100%) but lower sensitivity (50%) and NPV (87.9%). One patient with a PSV of 441 cm/sec on surveillance DUS died from complications of acute-on-chronic mesenteric ischemia. CONCLUSIONS: A PSV of 400 cm/sec on mesenteric DUS can predict ≥70% ISR with high sensitivity and should be considered as a diagnostic threshold for SMA in-stent restenosis.

Splanchnic venous thrombosis in a nephrotic patient following COVID-19 infection: a case report.

BACKGROUND: As the COVID-19 pandemic spread worldwide, case reports and small series identified its association with an increasing number of medical conditions including a propensity for thrombotic complications. And since the nephrotic syndrome is also a thrombophilic state, its co-occurrence with the SARS-CoV-2 infection is likely to be associated with an even higher risk of thrombosis, particularly in the presence of known or unknown additional risk factors. Lower extremity deep vein thrombosis (DVT) and pulmonary embolism (PE) are the most common manifestations of COVID-19-associated hypercoagulable state with other venous or arterial sites being much less frequently involved. Although splanchnic vein thrombosis (SVT) has been reported to be 25 times less common than usual site venous thromboembolism (VTE) and rarely occurs in nephrotic patients, it can have catastrophic consequences. A small number of SVT cases have been reported in COVID-19 infected patients in spite of their number exceeding 180 million worldwide. CASE PRESENTATION: An unvaccinated young adult male with steroid-dependent nephrotic syndrome (SDNS) who was in a complete nephrotic remission relapsed following contracting SARS-CoV-2 infection and developed abdominal pain and diarrhea. Abdominal US revealed portal vein thrombosis. The patient was anticoagulated, yet the SVT rapidly propagated to involve the spleno-mesenteric, intrahepatic and the right hepatic veins. In spite of mechanical thrombectomy, thrombolytics and anticoagulation, he developed mesenteric ischemia which progressed to gangrene leading to bowel resection and a complicated hospital course. CONCLUSION: Our case highlights the potential for a catastrophic outcome when COVID-19 infection occurs in those with a concomitant hypercoagulable state and reminds us of the need for a careful assessment of abdominal symptoms in SARS-CoV-2 infected patients.

Bowel ischemia in COVID-19: A systematic review.

BACKGROUND: Gastrointestinal complications of COVID-19 have been reported over the last year. One such manifestation is bowel ischaemia. This study thus aims to provide a more holistic review of our current understanding of COVID-19-induced bowel ischaemia. METHOD AND RESULTS: A meticulous search was performed using different keywords in PubMed and Google Scholar. Fifty-two articles were included in our study after applying inclusion and exclusion criteria and performing the qualitative assessment of the studies. A total of 25 702 patients were included in our study after the completion of the qualitative assessment. DISCUSSION: The common symptoms of GIT in COVID-19 patients are as diarrhoea, vomiting, nausea and abdominal pain. The mechanism of bowel ischaemia is associated with the formation of emboli which is related to COVID-19's high affinity for angiotensin-converting enzyme-2 on enterocytes, affecting the superior mesenteric vessels. Clinically, patients present with abdominal pain and vomiting. CT angiography of the abdomen and pelvis showed acute intestinal ischaemia (mesenteric). Management is usually initiated with gastric decompression, fluid resuscitation, and haemodynamic support. Surgical intervention is also sought. CONCLUSION: Intestinal ischaemia presenting in patients with COVID-19 has to be considered when symptoms of severe abdominal pain are present. More research and guidelines are required to triage patients with COVID-19 to suspect intestinal ischaemia and to help in diagnosis and management.

Improving midterm results justify the continued use of bare-metal stents for endovascular therapy for chronic mesenteric ischemia.

OBJECTIVE: The objective of this study was to evaluate the contemporary results of interventions in the celiac axis (CA) and superior mesenteric artery (SMA) for chronic mesenteric ischemia (CMI) and factors associated with patency and symptom-free survival. METHODS: A retrospective review of patients with CMI treated with angioplasty and stenting with bare-metal stents from 2003 to 2014 was conducted. Demographic, history, risk factor, preoperative testing, and technical variables were collected and subject to univariate analysis, with end points of patency loss. The patients were divided into early (2003-2008) and late (2009-2014) groups to compare early and contemporary results. Correlates of patency were then subject to further univariate and multivariable analysis. RESULTS: From 2003 to 2014, there were 150 patients (39 men, 111 women; age, 70.7 ± 11.1 years) with CMI who underwent interventions on the CA (56 vessels) and the SMA (133 vessels); 38 patients had both CA and SMA intervention. Primary patency for the CA was 86% (95% confidence interval [CI], 73-99) at 1 year and 66% (95% CI, 46-87) 3 years; for the SMA, primary patency was 81% (95% CI, 72-89) at 1 year and 69.0% (95% CI, 58-81) at 3 years. Increased age was associated with improved results in the SMA (hazard ratio [HR], 0.96; 95% CI, 0.92-1.00; P = .028). Chronic total occlusion in the SMA conferred worse patency compared with stenosis (HR, 2.38; 95% CI, 1.03-5.47; P = .042), and younger patients (<70 years) had a higher proportion of SMA occlusion (38.9% vs 22.8; P = .045). In the SMA, comparing early (2003-2008; 68 patients) vs late (2009-2014; 65 patients), primary patency was better in the late experience (3 years, 59% vs 77%; P = .016). The late cohort was older (early, 68.1 ± 12.5 years vs 72.5 ± 9.7 years; P = .024). The late cohort had a higher incidence of ostial flaring of the stent (early, 44.1%; late, 72.3%; P < .001). Multivariable analysis revealed only ostial flaring to be associated with improved patency in the SMA (HR, 0.29; 95% CI, 0.12-0.69; P = .006). CONCLUSIONS: Intervention for CMI has acceptable midterm results, and with experience and adoption of newer techniques, the results appear to be improving. Patients older than 70 years have better results than younger patients, and this may reflect a more malignant presentation in the younger patients. Ostial flaring proved to be the single factor on multivariate analysis associated with improved patency and was adopted in the late group. These data support the continued use of bare-metal stents in the treatment of CMI.