Preservation of pelvic perfusion with iliac branch devices does not decrease ischemic colitis compared with hypogastric embolization in endovascular abdominal aortic aneurysm repair.

OBJECTIVE: Ischemic colitis is a rare but devastating complication of endovascular repair of infrarenal abdominal aortic aneurysms. Although it is rare (0.9%) in standard endovascular aneurysm repair (EVAR), the incidence increases to 2% to 3% in EVAR with hypogastric artery embolization (HAE). This study investigated whether preservation of pelvic perfusion with iliac branch devices (IBDs) decreases the incidence of ischemic colitis. METHODS: We used the targeted EVAR module in the American College of Surgeons National Surgical Quality Improvement Program database to identify patients undergoing EVAR of infrarenal abdominal aortic aneurysm from 2012 to 2017. The cohort was further stratified into average-risk and high-risk groups. Average-risk patients were those who underwent elective repair for sizes of the aneurysms, whereas high-risk patients were repaired emergently for indications other than asymptomatic aneurysms. Within these groups, we examined the 30-day outcomes of standard EVARs, EVAR with HAE, and EVAR with IBDs. The primary outcome was the incidence of ischemic colitis. Secondary outcomes included mortality, major organ dysfunction, thromboembolism, length of stay, and return to the operating room. The χ2 test, Fisher exact test, Kruskal-Wallis test, and multivariate regression models were used for data analysis. RESULTS: There were 11,137 patients who had infrarenal EVAR identified. We designated this the all-risk cohort, which included 9263 EVAR, 531 EVAR-HAE, and 1343 EVAR-IBD procedures. These were further stratified into 9016 cases with average-risk patients and 2121 cases with high-risk patients. In the average-risk group, 7482 had EVAR, 411 had EVAR-HAE, and 1123 had EVAR-IBD. In the high-risk group, 1781 had EVAR, 120 had EVAR-HAE, and 220 had EVAR-IBD. There was no significant difference in 30-day outcomes (including ischemic colitis) between EVAR, EVAR-HAE, and EVAR-IBD in the all-risk and high-risk groups. In the average-risk cohort, EVAR-HAE was associated with a higher mortality rate than EVAR (2.2% vs 1.0%; adjusted odds ratio, 2.58; P = .01). Although EVAR-IBD was not superior to EVAR-HAE in 30-day mortality, major organ dysfunction, or ischemic colitis in this average-risk cohort, EVAR-IBD exhibited a trend toward lower mortality compared with EVAR-HAE in this cohort, but it was not statistically significant (1.0% vs 2.2%; adjusted odds ratio, 0.42; P = .07). CONCLUSIONS: Ischemic colitis is a rare complication of EVAR. HAE does not appear to increase the risk of ischemic colitis, and preservation of pelvic perfusion with IBDs does not decrease its incidence. Although HAE is associated with significantly higher mortality than standard EVAR in average-risk patients, the preservation of pelvic perfusion with IBDs does not appear to improve mortality over HAE.

Inferior mesenteric artery replantation does not decrease the risk of ischemic colitis after open infrarenal abdominal aortic aneurysm repair.

BACKGROUND: Ischemic colitis after an open abdominal aortic aneurysm (AAA) repair remains a serious complication with a nationally reported rate of 1% to 6% in elective cases and up to 60% after an aneurysmal rupture. To prevent this serious complication, inferior mesenteric artery (IMA) replantation is performed at the discretion of the surgeon based on his or her intraoperative findings, despite the lack of clear evidence to support this practice. The purpose of this study was to determine whether replantation of the IMA reduces the risk of ischemic colitis and improves the overall outcome of AAA repair. METHODS: Patients who underwent open infrarenal AAA repair were identified in the multicenter American College of Surgeons National Surgical Quality Improvement Program Targeted AAA Database from 2012 to 2015. Emergency cases, patients with chronically occluded IMAs, ruptured aneurysms with evidence of hypotension, and patients requiring visceral revascularization were excluded. The remaining elective cases were divided into two groups: those with IMA replantation (IMA-R) and those with IMA ligation. We measured the 30-day outcomes including mortality, morbidity, and perioperative outcomes. A multivariable logistic regression model was used for data analysis, adjusting for clinically relevant covariates. RESULTS: We identified 2397 patients who underwent AAA repair between 2012 and 2015, of which 135 patients (5.6%) had ischemic colitis. After applying the appropriate exclusion criteria, there were 672 patients who were included in our study. This cohort was divided into two groups: 35 patients with IMA-R and 637 patients with IMA ligation. There were no major differences in preoperative comorbidities between the two groups. IMA-R was associated with increased mean operative time (319.7 ± 117.8 minutes vs 242.4 ± 109.3 minutes; P < .001). Examination of 30-day outcomes revealed patients with IMA-R had a higher rate of return to the operating room (20.0% vs 7.2%; P = .006), a higher rate of wound complications (17.1% vs 3.0%; P = .001), and a higher incidence of ischemic colitis (8.6% vs 2.4%; P = .027). There were no significant differences in mortality, pulmonary complications, or renal complications between the two groups. In multivariable analysis, IMA-R was a significant predictor of ischemic colitis and wound complications. CONCLUSIONS: These data suggest that IMA-R is not associated with protection from ischemic colitis after open AAA repair. The role of IMA-R remains to be identified.

Ischemic colitis complicating major vascular surgery.

Ischemic colitis is a well-described complication of major vascular surgery, especially following open abdominal aortic aneurysm repair and endovascular aneurysm repair, but also with aortoiliac surgery, aortic dissection, and thoracic aneurysm repair. Following its onset, mortality remains high, highlighting the need for rapidly identifying the onset of symptoms and, perhaps more importantly, those patients at risk, in an attempt to prevent its onset. In this article, the authors review the causes, presentation, and diagnostic strategies of colonic ischemia. They also cover the operative management and outcomes for bowel resection and vascular repair. Finally, they evaluate some of the newer options for diagnosing this condition.

Replanting the inferior mesentery artery during infrarenal aortic aneurysm repair: influence on postoperative colon ischemia.

BACKGROUND: Replanting the inferior mesentery artery (IMA) to prevent ischemic colitis (IC) has been discussed for many years; yet, to our knowledge, no prospective studies have been conducted to compare the incidence of histologically proven IC in patients with and without IMA revascularization. The aim of this prospective study, with histologic evaluation of the sigmoid colon mucosa, was to assess the influence of replanting the IMA on IC and mortality. METHODS: From January 1999 to December 2003, 160 consecutive patients who were operated on for a symptomatic (n = 21) or asymptomatic (n = 139) infrarenal aortic aneurysm were prospectively assessed and randomly assigned either to replanting or ligating the IMA. Sigmoidoscopy with biopsy was performed on day 4 or 5 after surgery; an autopsy was performed on patients not surviving to day 5 after surgery. All patients gave written informed consent. RESULTS: Of the 160 randomized patients, 128 had a confirmed patent IMA and formed the basis of this study. Their age was 70 +/- 8 years (men, 70 +/- 8 years; women, 73 +/- 7 years). The IMA was replanted in 67 patients (52%) and ligated in 61 (48%) intraoperatively. IC developed in six patients with a replanted IMA and in 10 with a ligated IMA (relative risk [RR], 0.55; 95% confidence interval [CI], 0.21 to 1.41; chi2 = 1.62; P = .203). Blood loss in the two cohorts did not differ significantly (P = .788); however, patients with IC had a significantly higher blood loss compared with the cohort without IC (P = .012) and were older (P = .017). Age, sex distribution, clamping time, the use of tube or bifurcated grafts, and intraoperative hypotension did not differ between patients with ligated or replanted IMA. CONCLUSION: Although replanting the IMA did not confer a statistically significant reduction of perioperative morbidity or mortality in this study, it appears that older patients and patients with increased intraoperative blood loss might benefit from IMA replantation, because this maneuver does not increase perioperative morbidity or substantially increase operation time.

[Prevention of intestinal ischemia after abdominal aortic reconstructive surgery]. / Zarnyno isemijos prevencija po pilvo aortos rekonstrukciniu operaciju.

UNLABELLED: The aim of this study was to estimate rate of intestinal ischemic complications after abdominal aortic reconstructive surgery, to evaluate risk factors and to provide means of prevention of complication. MATERIAL AND METHODS: Study group consisted of 172 patients who underwent aortic reconstruction in 2000-2003 in the Department of Vascular Surgery of Kaunas University of Medicine Hospital. Six patients underwent intestinal ischemia in the postoperative period, i. e. 3.5%; four of them died. This indicated that 13% of patients died after abdominal aortic surgery. Ninety-four patients underwent operation for aortoiliac occlusive disease, colon ischemia occurred in 1 case (1.1%). Seventy-eight patients underwent abdominal aortic aneurysm; 33 patients -- ruptured aneurysm, and 45 -- aneurysm without rupture. In ruptured abdominal aortic aneurysm group with III degree colon ischemia there were 3 cases (9.1%); 2 of them died, which formed 11% of all deaths in this group. In the group of non-ruptured abdominal aortic aneurysm with III degree colon ischemia there were 2 cases (4.4%). Both patients died, which formed 50% of all deaths in this group. For all patients operated for abdominal aortic aneurysm, a. mesenterica inferior stump pressure was evaluated. In case of stump pressure 50 mmHg and more a. mesenterica inferior was ligated. If pressure was lower than 50 mmHg a. mesenterica inferior was reimplanted into vascular graft. Forty-nine reconstructions of a. mesenterica inferior were made in abdominal aortic aneurysm group: 25 in ruptured cases, and 24 in non-ruptured cases. Despite the fact that a. mesenterica inferior was reconstructed, 2 patients had colon ischemia after this reconstruction in the group of ruptured aneurysm. In the group of non-ruptured aneurysm, colon ischemia developed only after ligation of a. mesenterica inferior. We conclude that a. mesenterica inferior is very important for normal circulation of left colon. Correct evaluation of preoperative aortography, correct operative strategy, and reimplanted a. mesenterica inferior if it is necessary -- are the main means of colon ischemia prevention after abdominal aortic surgery.

[Gastrointestinal tonometry: a new tool for the anesthesiologist]. / Tonometría gastrointestinal: una nueva herramienta para el anestesiólogo.

Intestinal hypoperfusion is among the factors implicated in sepsis and multiorgan failure. Splanchnic blood flow may be sacrificed to maintain supply to vital organs, even when hemodynamic alterations are minor. The sensitivity of invasive hemodynamic monitoring for detecting intestinal hypoperfusion is low. This paper aims to review current knowledge about indirect measurement of splanchnic perfusion by way of gastrointestinal tonometry. We review the pathophysiology of ischemic intestinal lesions, the basis for gastrointestinal tonometry, and the method. Finally we discuss clinical applications (early diagnosis of ischemic colitis and ischemia of the flap after esophageal reconstruction, weaning from mechanical ventilation, abdominal compartment syndrome, liver transplant, heart surgery, prognostic factors and care of the critically ill patient). An adequate understanding of this monitoring technique and management of information it provides can give an early warning of the intestinal hypoperfusion that precedes other serious systemic complications.

Short-chain fatty acid enemas stimulate plasminogen activator inhibitor-1 after abdominal aortic graft surgery: a double-blinded, placebo-controlled study.

Colonic ischaemia may complicate aortic graft surgery with high mortality from associated colonic necrosis. Loss of the mucosal barrier function due to ischaemia may promote translocation of endotoxins with secondary systemic disseminated coagulation leading to multiple organ failure. Short-chain fatty acids (SCFAs) stimulate the microcirculation in the human rectum. The aim of this study was to investigate whether SCFA enemas influence systemic endotoxinaemia and fibrinolytic activity during and after elective aortic graft surgery for arteriosclerosis. Thirty-two patients were randomized to SCFA or placebo enemas twice daily from the day before surgery to 7 days after. Blood samples for endotoxin, plasminogen activator inhibitor-1 (PAI-1) activity, tissue-type plasminogen activator (t-PA) antigen, and cross-linked fibrin degradation products (XL-FDP) were drawn before, during, and 7 days after surgery. Four patients, two in each treatment group, developed postoperative endotoxinaemia. PAI-1 was significantly higher on days 2 and 4 in SCFA-treated patients, whereas t-PA was comparable Petween the groups. During the postoperative course, a progressive and near-identical XL-FDP increase was found in the two groups. In elective aortic graft surgery for arteriosclerosis, SCFA enemas likely stimulate systemic PAI-1 activity by promoting colonic tissue reperfusion following aortic unclamping. Endotoxinaemia and fibrinolytic shutdown are uncommon findings.

Does laser Doppler flowmetry aid the prevention of ischemic colitis in abdominal aortic aneurysm surgery?

Acute ischemic colitis is noted as a rare but lethal complication of abdominal aortic aneurysm (AAA) surgery. Because of its high mortality a reliable method of monitoring colonic blood perfusion to predict the possible occurrence of ischemic colitis is highly desirable for AAA surgery. We have tested the use of a laser Doppler flowmeter placed on the surface of the sigmoid colon for intraoperative monitoring in 31 patients with AAA. Although most of the patients showed the same flow levels after aorto-iliac or aorto-femoral grafting (at least unilaterally the internal iliac artery was perfused), in 6 cases poor colonic perfusion (below 50% of the basal flow) was observed and inferior mesentric arterial reconstruction was performed. In these 6 patients, sigmoid colonic blood perfusion returned from 37% to 82% of preoperative value after the reconstructions. No ischemic colitis was noted in this series of patients. We suggest that monitoring of serosal blood flow in the sigmoid colon using a laser Doppler flowmeter is useful for the management of patients during abdominal aortic aneurysm surgery.

Pelvic radiation therapy as a risk factor for ischemic colitis complicating abdominal aortic reconstruction.

Ischemic colitis is an infrequent but potentially devastating complication of abdominal aortic reconstruction. Identification of patients with predisposing risk factors for the development of ischemic colitis can guide intraoperative measures to preserve or restore colonic blood flow during aortic surgery. Previous radiation therapy for pelvic malignancy may be one such predisposing risk factor. Two cases are presented in which ischemic colitis complicated abdominal aortic reconstruction in the setting of previous pelvic irradiation. In the months after radiation therapy for prostate cancer, one patient underwent infrarenal abdominal aortic aneurysm repair. Ischemic infarction of the sigmoid colon developed acutely after surgery and required emergent sigmoid colectomy. The second patient underwent reconstruction of an infrarenal abdominal aortic aneurysm after having had radiation therapy for a bladder tumor. Despite an initial satisfactory result, the patient's abdominal pain and diarrhea progressively worsened and he eventually required sigmoid colectomy for severe ischemic colitis. In both of these patients, the inferior mesenteric arteries were patent and had not been reimplanted. The association of pelvic radiation therapy with ischemic colitis after aortic reconstruction should focus attention to the operative details for maintaining the colonic circulation in these patients. Reimplantation of the inferior mesenteric artery in particular may prevent both the acute and the insidious variants of this complication in patients who undergo aortic surgery and decrease the incidence of this complication in patients with a history of radiation therapy to the pelvis.

[Role of coagulation disorders in mesenteric ischemia]. / Place des anomalies de la coagulation dans l'ischémie mésentérique.

Mesenteric ischemic process can lead to bowel infarction or indolent low-grade ischemia. Inherited thrombophilia represents about 30 to 40% of mesenteric vein thrombosis. Analysis of thromboembolism sites occurring during genetic defect of coagulant factors showed that mesenteric thrombosis is the third localization after lung and legs, in equal incidence with cerebral thrombosis. The genetic defects known to be associated with thrombophilia, as deficiencies of protein C, protein S, antithrombin III, and dysfibrinogenemia, are discussed. A special interest is devoted to resistance to activated protein C. Acquired diseases, as myeloproliferative disease or paroxysmal nocturnal hemoglobinemia, inducing thrombosis are also discussed. Recent advances in both basic and clinical research have provided new insights that may be integrated into diagnostic and therapeutic practices.