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Mesenteric Ischaemia - Overview of management approach. Joint Hospital Surgical Grand Round Dr Shirley Liu Department of Surgery North District Hospital. Mesenteric Ischaemia. “Occlusion of the mesenteric vessels is apt to be regarded as one of those condition of which
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Mesenteric Ischaemia- Overview of management approach Joint Hospital Surgical Grand Round Dr Shirley Liu Department of Surgery North District Hospital
Mesenteric Ischaemia “Occlusion of the mesenteric vessels is apt to be regarded as one of those condition of which …the diagnosis is impossible, …the prognosis hopeless, …and the treatment almost useless” A.J. Cokkinis 1926 Cokkinis AJ. Mesenteric vascular occlusion. London, Bailliere, Tindall and Cox. 1926pp1-93
Pathophysiology Resting bowel: 20% cardiac output Postprandial bowel: 35% cardiac output Bradbury AW, et al. Br J Surg 1995;82:1446-1459
Mesenteric arteries SMA IMA Acute SMA occlusion Ischaemic colitis Affect small and large bowel Affect large bowel alone
What happens to bowel during absolute ischaemia? • 15 mins - Structural changes to intestinal villi • 3 hours • - Mucosal sloughing • - Still reversible Time is crucial ! • 6 hours • - Transmural necrosis • - Gangrene • - Perforation 15 mins 3 hours 6 hours Absolute ischaemia Udassin R, et al. J Surg Res 1994;56:221-5
Arterial occlusion Venous occlusion Non-occlusive Mesenteric Venous thrombosis (MVT) 15% Non-occlusive Mesenteric ischaemia (NOMI) 15% Embolism 20-30% Thrombosis 50% Mesenteric ischaemia Acute Mesenteric Ischaemia Chronic Mesenteric Ischaemia Bradbury AW, et al. Br J Surg 1995;82:1446-1459
Management of acute mesenteric ischaemia Clinical suspicion Ischaemic bowel cannot be excluded Exclude other non-vascular abdominal emergencies Unstable/ Peritonism present Stable & Peritonism absent Diagnosis not certain negative finding CT scan or angiography Positive finding Non-occlusive mesenteric ischaemia Mesenteric Venous thrombosis SMA occlusion Trans-arterial vasodilator infusion Immediate heparinization Surgical treatment No improvement
Management of acute mesenteric ischaemia Clinical suspicion Ischaemic bowel cannot be excluded Exclude other non-vascular abdominal emergencies
Elderly patients Associated comorbidities: Hypertension 60% IHD 58% Diabetes 35% AF 28% Renal failure 25% Peripheral vascular disease 18% Clinical suspicion… Past history of atherosclerotic diseases Park WM, et al. J Vasc Surg 2002;35:445-52
Symptoms and signs Abdominal pain95% - Pain out of proportion of signs Nausea 44% Vomiting 35% Diarrhea 35% PR bleeding 16% Fever 46% Tachycardia 58% Abd distension 66% Laboratory tests Leukocytosis Elevated urea Elevated creatinine Elevated lactate Metabolic acidosis DIC Clinical suspicion… Most symptoms and signs are non-specific Need to exclude other non-vascular emergencies Endean ED, et al. Ann Surg 2001;233:801-808 Park WM, et al. J Vasc Surg 2002;35:445-52 Sreedharan S, et al. Singapore Med J 2007;48:319-23
Signs suggestive of • bowel infarction: • - Dilated thickened bowel loops • - Ground glass appearance • - Thumb printing • - Pneumatosis intestinalis • - Gas in portal vein Clinical suspicion… Normal plain X-ray
Sudden abdominal pain Gut emptying Cardiac source of embolization Clinical triad… Klass AA. Ann Surg 1951;134:913-917 Acute Mesenteric ischaemia
Unstable/ Peritonism present Stable & Peritonism absent Diagnosis not certain Surgical treatment Management of acute mesenteric ischaemia Clinical suspicion Ischaemic bowel cannot be excluded Exclude other non-vascular abdominal emergencies CT scan or angiography
Features in CT scan Bowel wall thickening Non-enhanced bowel wall SMA thrombus Fluid collection Pneumatosis intestinalis Portal venous gas Wiesner W, et al. Radiology 2003;226:635-50
CT angiogram Kirkpatrick ID, et al. Radiology 2003;229:91-98
CT scan vs Angiography CT scan - More preferred choice - Can exclude other non-vascular emergencies if diagnostic confusion Both are time-consuming - introduce critical delay in management
negative finding Positive finding SMA occlusion Management of acute mesenteric ischaemia Clinical suspicion Ischaemic bowel cannot be excluded Exclude other non-vascular abdominal emergencies Unstable/ Peritonism present Stable & Peritonism absent Diagnosis not certain CT scan or angiography Surgical treatment
SMA Embolism SMA Thrombosis Aortic ostium ~15% Aortic ostium ~60-80% Around Middle colic artery ~40% Around Middle colic artery ~15% Distal branches ~45% Distal branches ~5% Acute SMA Occlusion Acosta S, et al. Ann Surg 2005;241:516-22
Immediate resuscitation… Before operation • Bowel rest • Fluid resuscitation • Close hemodynamic monitoring • Nasogastric decompression • Indwelling urinary catheterization • Parenteral antibiotics • Anticoagulation by heparin Schwartz LB, et al. Surg Clin North Am 1997;77:307-318
Definitive surgical exploration Midline laparotomy 1. Assessment of bowel viability 2. Determination of underlying cause 3. Mesenteric revascularization 4. Resection of necrotic bowel 5. Second look laparotomy
1. Clinical Judgment - pink serosa - visible peristalsis - positive pulsations - bleeding from cut edges (Ballard JL, et al. Am Surg 1993;59:309-11) 2. Doppler USG - hand-held doppler (Hobson RW, et al. J Surg Res 1976;20:231-5) 3. Fluorescein -Injection of fluorescein and inspection under Wood’s lamp (Bergman RT, et al. Ann Vasc Surg 1992; 6:74-9) Assessment of bowel viability
Assessment of bowel viability Equivocal viability Necrotic bowel Extensive infarction Limited infarction Revascularization procedures Tender loving care
Palpate Main trunk of SMA Pulse present proximally but not distally Absent pulse Thrombosis Embolism Determination of underlying cause:Thrombosis or embolism?
Thrombosis Embolism Balloon catheter embolectomy ± Vein patch angioplasty Thrombectomy Bypass grafting Reimplantation of SMA Mesenteric Revascularization
Revascularization procedures…(1) Bypass grafting • Direction • Antegrade bypass from supraceliac aorta • Retrograde bypass from infrarenal aorta • Both are equally good • Conduit • Autologous graft • Propensity to kink • Synthetic graft • Contamination during bowel resection may cause synthetic graft infection Foley MI, et al. J Vasc Surg 2000;32:37-47 Bradbury AW, et al. Br J Surg 1995;82:1446-1459
Revascularization procedures…(2) Reimplantation of SMA • Aortomesenteric bypass is time-consuming • Direct reimplantation of SMA is quicker • Recommended as procedure of choice Testart J, et al. Int Angiol 1992;11:181-5
Resection of necrotic bowel Anastomosis should not be attempted • Equivocal viability at cut ends • Exteriorize as stomas
Routine after 24-48 hours - allow reassessment of bowel viability - claim to have reduced mortality Selective approach - increased operative risks for second operation - suggest only when clinical deterioration - but means further infarction with worse outcome Levy PJ, et al. Surg Gynecol Obstet 1990;170:287-91 Hagmuller GW, et al. Langenbecks Arch Chir 1990:311-15 Second look laparotomy Who should undergo second look laparotomy?
Acute SMA thrombosis NOMI Percutaneous balloon angioplasty ± stenting Transarterial thrombolysis Transarterial infusion of vasodilator Limited use in acute situations • Cannot assess bowel viability • Only indicated in early cases without bowel infarction Alternative to surgery…Endovascular therapy
Management of acute mesenteric ischaemia Clinical suspicion Ischaemic bowel cannot be excluded Exclude other non-vascular abdominal emergencies Unstable/ Peritonism present Stable & Peritonism absent Diagnosis not certain negative finding CT scan or angiography Non-occlusive mesenteric ischaemia Mesenteric Venous thrombosis SMA occlusion Trans-arterial vasodilator infusion Immediate heparinization Surgical treatment No improvement
Non-occlusive mesenteric ischaemia (NOMI) Etiology: no occlusion • Low cardiac output • Mesenteric vasospasm Treatment is non-surgical • Treat underlying cause • Transarterial infusion of vasodilator (papeverine) Bradbury AW, et al. Br J Surg 1995;82:1446-1459
Secondary MVT (60%) - Portal hypertension - Intraabdominal sepsis - Intraabdominal neoplasia - Pancreatitis - Trauma Primary MVT (40%) - any hypercoagulable states • Treatment is non-surgical • Heparinization • Thrombophilia screening Mesenteric venous thrombosis (MVT) Bradbury AW, et al. Br J Surg 1995;82:1446-1459
Prognosis of acute mesenteric ischaemia Overall average mortality 60-80% Ischaemic reperfusion injury Multiorgan failure Park WM, et al. J Vasc Surg 2002;35:445-52
Conclusion Acute mesenteric ischaemia • Morbid condition • High mortality rate High index of suspicion • Pain out of proportion of signs • Early recognition is crucial
Management of acute mesenteric ischaemia Clinical suspicion Ischaemic bowel cannot be excluded Exclude other non-vascular abdominal emergencies Unstable/ Peritonism present Stable & Peritonism absent Diagnosis not certain negative finding CT scan or angiography Positive finding Non-occlusive mesenteric ischaemia Mesenteric Venous thrombosis SMA occlusion Trans-arterial vasodilator infusion Immediate heparinization Surgical treatment No improvement
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