SMA Thromboembolism - Department of Surgery at SUNY ...downstatesurgery.org/files/Mesenteric...

SMA Thromboembolism

Marc LaFonte PGY 4

SUNY Downstate June 18th, 2015

www.downstatesurgery.org

Case Presentation

68 M generalized intermittent abdominal pain x 1 week, localized b/l lower quadrants +F, +BM non bloody, + anorexia, no association with meals No prior colonoscopy PMH: afib not on anti-coagulation PSH: non-contributory Social: smoker 1PPD x 40 years Meds: none NKA


Physical Exam

Vitals: T 97.3F, BP 154/91, HR 62, RR 20, 95% RA AAOx3, NAD Abd: soft, non-distended, mild tenderness b/l lower abdomen Rectal: Guaiac negative, no masses


Presenter

Presentation Notes

Patient presented 10pm, CT done 2:20am, surgery consulted 3:30am

Laboratory and Radiological Studies

13.7 > 15.1/48.4 < 192 143 / 3.1 | 97 / 25 | 14 / 1.02 < 197 LFT WNL, Lipase 29 Lactate 5.5 UA negative CXR: bibasalar atelectasis


CT: Abdomen/pelvis Jejunal branch of SMA occluded R colic vein possibly occluded No portal venous gas, no thickened bowel no extravasation of PO contrast No free fluid


Assessment and Plan

Admitted to SICU Started on heparin drip Aggressive IV hydration, broad spectrum abx Plan for mesenteric angiogram Pain worsened OR


Presenter

Presentation Notes

Pain worsened 8am, OR 10am

OR

Exploratory laparotomy – serous fluid Proximal small bowel perfused Extensive necrosis mid jejunum and mid ileum (total 150cm) - resected Remainder of jejunum and distal ileum viable SMA non-pulsatile, heavily diseased; SMV distended


Presenter

Presentation Notes

Embolectomy with #2 and #3 Fogarty catheters

OR Continued

Transverse arteriotomy proximal to right colic, embolectomy. SMA tore, converted to longitudinal, Dacron patch placed Non-pulsatile SMA, patch incised, Fogarty passed, no clots GI left in discontinuity, abdomen left open, transferred to SICU


Presenter

Presentation Notes

Irreversible ischemia with microcirculatory gut thrombosis

Post-Operative Course

POD#0 profoundly hypotensive, crash laparotomy at bedside: patches of necrosis and ischemia of small bowel and R colon Made DNR Terminal extubation


Questions?


SMA Thromboembolism

•Spectrum of Mesenteric ischemia Syndromes

•Majority Heart

•Incidence 5.3 cases/100,000 •3:1 F:M •Age > 60

•Highly lethal: average mortality 69%


Presenter

Presentation Notes

Other pathologic mechanisms: arterial dissections, acute thrombosis of a chronic SMA atherosclerotic lesion, low flow nonocclusive mesenteric ischemia (NOMI), mesenteric venous thrombosis

“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.”

Dr. A. J. Cokkinis 1920’s


Anatomy


Presenter

Presentation Notes

SMA arises from anterior aorta 1-2cm below celiac artery, and 1-2cm cephalad to renal take off, at the level of the first lumbar vertebral body. As it courses inferior and to the right, it goes posterior to the pancreas and anterior to the 4th portion of the duodenum.

Anatomy •Early branches: Inferior PDA and middle colic artery

•Change caliber •Proximal jejunum to splenic flexure at risk

•Acute occlusion celiac or IMA more tolerated


Presenter

Presentation Notes

More tolerated due to pancreaticoduodenal arteries between CA and SMA, IMA can provide collateral flow to SMA through Drummond’s artery, arc of Riolan, and the meandering mesenteric arteries. In addition, IMA and hindgut further supplied by collaterals through hypogastric and hemorrhoidal arterial networks.

Anatomy


Presenter

Presentation Notes

Angio: abrupt cutoff of middle colic artery from emboli secondary to afib

Pathophysiology

Ischemia bowel mucosa Epi + Endothelial damage lose mucosal barrier Bacterial invasion, enzyme degradation inflammatory mediators microcirculatory stasis, edema intravascular thrombosis


Presenter

Presentation Notes

Even when perfusion is restored, the dysfunction persists. “Ischemia-reprofusion” syndrome that drives multiorgan failure.

Presentation Acute Mesenteric Ischemia

•High index of suspicion

•Search for hx of dysrhythmias, MI, valvular disease, CHF, atherosclerosis, malignancy

•“Classic” sudden, epigastric/midabdominal pain out of proportion to exam, followed by defecation +/- blood

•+/- vomiting •When acute on chronic, may endorse anorexia, postprandial colicky pain, weight loss


Physical Exam

•Subtle and nonspecific

•Vitals normal •Abdomen non tender or vaguely tender

•25% non tender •Distension, diminished bowel sounds •NGT lavage and rectal may show blood

•If patient looks toxic/peritoneal, bowel infarction and necrosis is already present


Labs

•No test is sensitive or specific

• Possibly leukocytosis, hemoconcentration

•Late hints may include metabolic acidosis and lactate elevation, hyperkalemia


Abdominal Radiograph

•Search for pneumoperitoneum, pneumoatosis intestinalis, portal venous gas

•Most commonly: adynamic ileus with a gasless abdomen

•Can help exclude obstruction, volvulus


Other Imaging

• Duplex U/S

•Peak systolic SMA > 275cm/s (92% sen, 96% spec)

•CT angiogram: AP/lateral views •Meniscus sign from embolism to middle colic artery •May also show mesenteric vein “target sign”

•Upper endoscopy, colonoscopy not indicated •Barium contraindicated – obscures mesenteric circulation, if intraperitoneal can cause peritonitis and add challenges during revascularization

•**Mesenteric Angiogram**


Presenter

Presentation Notes

Mesenteric angiogram can really help with pre-operative planning and may even allow for temporary re-vascularization options but it should not preclude surgical exploration. Options include urokinase and recombinant TPA have been successful in small case reports. This should be performed within 12 hours in a stable patient. MR Angio also described, limited to celiac and SMA, good for contrast allergy

Initial Management

• Fluid resuscitation

•May have to add sodium bicarbonate if metabolic acidosis not improving

•Systemic anticoagulation (heparin)

•Prevents further thrombus propagation

•Broad spectrum antibiotics


Surgical Treatment Principles: Thromboembolectomy

•Identify and remove gangrenous/perforated bowel to reduce soilage

•Locate cause of bowel loss •Compromise to jejunum, ileum, and colon = SMA occlusion at origin •Sparing of 1st portion of jejunum or patchy ischemia = emboli (or vasospasm)

• Plan for a second look at 24-48 hours


Surgical Treatment: Acute Embolic Mesenteric Ischemia

Lift omentum and transverse colon cephalad Retract small bowel right, pack sigmoid left Divide LoT, mobilize duodenum Palpate SMA at base of transverse colon mesentery Confirm with doppler


Presenter

Presentation Notes

Confirm with doppler because may have water hammer pulse proximal to occlusion If SMA cannot be confirmed, proceed with SMA embolectomy

Surgical Treatment: Acute Embolic Mesenteric Ischemia

Expose 3-4cm SMA, palpate Transverse arteriotomy (planning to close) Longitudinal (bypass) Fogarty passed proximal and distal until negative clot Close arteriotomy


Presenter

Presentation Notes

SMA larger caliber proximal to middle colic origin Only inflate Fogarty during withdrawl Close transverse arteriotomy with interrupted monofilament Close longitudinal with patch to prevent stenosis

Thrombotic Mesenteric Ischemia: Bypass Options and Principles

Usually involves at least 2 of 3 mesenteric arteries In acute setting, aortomesenteric revascularization expeditious and durable Non-acute, two-vessel revascularization to the SMA from aorta Inflow sites include iliacs, supraceliac or infrarenal aorta Choose conduit based on clinical scenario (autogenous vs. prosthetic) Wait 30 minutes after revascularization to re-assess bowel Adjuncts include Doppler (anti-mesenteric border) or fluorescence under Wood lamp


Presenter

Presentation Notes

Supraceliac abdominal aorta devoid of severe atherosclerosis vs. infrarenal aorta (less complications from cross clamp) Supraceliac aorta allows for short antegrade bypass to CA and SMA (reduces kinking chance) Infrarenal aorta or iliac arteries provides retrograde bypass to the CA or SMA which are easier to access vs. the suprarenal aorta Saphenous vein is the conduit of choice

Bypass Options: Antegrade Aortomesenteric


Bypass Options: Retrograde Aortomesenteric


Bypass Options: Ileomesenteric


Endovascular Options

Used in setting of chronic mesenteric ischemia Indication primary stent placement (not clearly defined) Calcified ostial stenosis High grade eccentric stenosis Residual stenosis >30% Dissection after angioplasty In acute setting: Indicated when presentation within 12 hours symptoms Big drawbacks Inability to assess bowel Prolonged time for success


Presenter

Presentation Notes

Ideal for high operative risk from medical comorbidities Prolonged time to success due to serial angiographic surveillance to assess thrombus resolution.

•Journal of Vascular Surgery 2002 •1990-2000

•Retrospective Mayo Clinic

•58 patients •Embolic (28%) •Thrombotic (64%) •Non-occlusive (8%)


•Presentation: •95% severe acute abdominal pain

•43% prior chronic mesenteric ischemia symptoms •65% vs 6% thrombus vs. embolus group

•81% Angiography

•Distinction between embolism and thrombosis not always made prior to surgery

•OR •Revascularization (single vessel bypass) •53% bowel resection at first look •50% second look, 50% required additional bowel resection


Presenter

Presentation Notes

Chronic symptoms mean duration 8 months Graft in 39 patients (favored supraceliac aorta over infrarenal aorta), vein in 5

•Major complications 79% •Respiratory failure and multiorgan failure

•Mortality 30 Day = 32%

•31% embolism, 32% thrombosis, 80% NOMI

•24 patients died within 90 days (23 in hospital) •Cardiac, short bowel, mesenteric ischemia recurrence


High index of suspicion – look for risk factors Clinical picture does not reflect severity Time is the major factor , prompt peri-operative planning At surgery, focus on re-vascularization, know options in each scenario Second look!

Summary


References Fischer et al. Mastery of Surgery ,6th edition Schwartz’s Principles of Surgery, 9th edition Zelenock G et al. Mastery of Vascular and Endovascular Surgery Park W. et al. Contemporary management of acute mesenteric ischemia : Factors associated with Survival Journal of Vascular Surgery 2002


SMA Thromboembolism - Department of Surgery at SUNY ...downstatesurgery.org/files/Mesenteric...

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