Ischemic Colitis after Cardiac Surgery: Can We Foresee the Threat?

Abstract

IntroductionIschemic colitis (IC) remains a great threat after cardiac surgery with use of extracorporeal circulation. We aimed to identify predictive risk factors and influence of early catecholamine therapy for this disease.MethodsWe prospectively collected and analyzed data of 224 patients, who underwent laparotomy due to IC after initial cardiac surgery with use of extracorporeal circulation during 2002 and 2014. For further comparability 58 patients were identified, who underwent bypass surgery, aortic valve replacement or combination of both. Age ±5 years, sex, BMI ± 5, left ventricular function, peripheral arterial disease, diabetes and urgency status were used for match-pair analysis (1:1) to compare outcome and detect predictive risk factors. Highest catecholamine doses during 1 POD were compared for possible predictive potential.ResultsPatients’ baseline characteristics showed no significant differences. In-hospital mortality of the IC group with a mean age of 71 years (14% female) was significantly higher than the control group with a mean age of 70 (14% female) (67% vs. 16%, p<0.001). Despite significantly longer bypass time in the IC group (133 ± 68 vs. 101 ± 42, p = 0.003), cross-clamp time remained comparable (64 ± 33 vs. 56 ± 25 p = 0.150). The majority of the IC group suffered low-output syndrome (71% vs. 14%, p<0.001) leading to significant higher lactate values within first 24h after operation (55 ± 46 mg/dl vs. 31 ± 30 mg/dl, p = 0.002). Logistic regression revealed elevated lactate values to be significant predictor for colectomy during the postoperative course (HR 1.008, CI 95% 1.003–1.014, p = 0.003). However, Receiver Operating Characteristic Curve calculates a cut-off value for lactate of 22.5 mg/dl (sensitivity 73% and specificity 57%). Furthermore, multivariate analysis showed low-output syndrome (HR 4.301, CI 95% 2.108–8.776, p<0.001) and vasopressin therapy (HR 1.108, CI 95% 1.012–1.213, p = 0.027) significantly influencing necessity of laparotomy.ConclusionPatients who undergo laparotomy for IC after initial cardiac surgery have a substantial in-hospital mortality risk. Early postoperative catecholamine levels do not influence the development of an IC except vasopressin. Elevated lactate remains merely a vague predictive risk factor.

Review article: the pharmacological causes of colon ischaemia

“…This mechanism, although helpful to the patient with severe hypotension, is also the explanation for the associated colonic ischaemia . Vasopressin is also administered after cardiopulmonary bypass surgery and has been shown to be a risk factor for developing colonic ischaemia in those patients as well . In one study of pigs undergoing cardiopulmonary bypass, vasopressin was shown to decrease rectosigmoid perfusion compared with a sham infusion .…”

“…In patients with hypotension and cardiopulmonary bypass, it is unclear if hypotension, the medication, or the combination of the two causes the ischaemic episode. Regardless, these patients are clearly at risk for colonic ischaemia and should be monitored for signs of this disease …”

Vasopressin therapy in cardiac surgery

“…The only independent predictors of this complication in multivariate regression analysis were max dose of AVP (not defined in the study) and low cardiac output syndrome. 42 As with acute kidney injury, it appears that doses higher than 0.1 U/min are associated with postoperative complications.…”

Advents in the Diagnosis and Management of Ischemic Colitis

“…Ischemic colitis after cardiovascular surgery with cardiopulmonary bypass (CPB) is a rare complication with an incidence of <1% and poor outcome with a mortality rate of 30–100% ( 33 , 38 ). Distended or acute abdomen accompanied by low output syndrome with/without lower gastrointestinal tract bleeding may urge for direct diagnostic evaluation and prompt surgical intervention.…”

“…CPB may cause systemic inflammatory response syndrome (SIRS) leading to barrier loss at the colonic mucosa. Moreover, regional differences in perfusion in the bowel wall, accompanied by hypothermia and normothermia and the use of vasoconstrictors or vasopressin may aggravate mucosal ischemia ( 33 , 39 ). Duration of cross clamp, use of intra-aortic balloon pump support, and serum lactate concentrations >5 mmol/L were found to be significant predictive factors for the development of non-occlusive mesenteric ischemia after cardiac surgery ( 40 , 41 ) Low cardiac output may lead to diminished splanchnic perfusion leading to irreversible damage to the intestinal wall.…”