Git j club mesenteric ischemia nejm.

Dr. Mohamed Alshekhani
Professor in Medicine
MBChB-CABM-FRCP-EBGH
2016
1

BO5:1
• 1. Abdominal pain due to mesenteric ischemia is
• A. Rare.
• B. Uncommon.
• C. Common.
• D. Very common.
• E. Not uncommon.

BO5:2
• 2. The mortality from acute mesenteric ischemia is:
• A. Rare.
• B. Uncommon.
• C. Common.
• D. Very common.
• E. Not uncommon.

BO5:3
• 3. The most common cause of mesenteric ischemia is:
• A. Acute throbosis.
• B. Acute embolism.
• C. Acute dissection.
• D. Chronic atherosclerotic occlusion.
• E. Venous thrombosis.

BO5:4
• 4. The sequence of events in pathophysiology of acute mesenteric
ischemia include all except:
• A. Initial Vasospasm.
• B. Intestinal bacterial translocation.
• C. Systemic inflammatory response.
• D. Vasoconstriction.
• E. Intestinal infarction.

BO5:5
• 5. Mesenteric ischemia differs from other major organs
atherosclerotic ischemias by being:
• A. More common.
• B. Less lethal.
• C. More common in females.
• D. Easier to be diagnosis.
• E. All of the above.

BO5:6
• 6. The abdominal pain of acute mesenteric ischemia have more
similar characteristics to:
• A. Acute appendisitis.
• B. Acute cholecystitis.
• C. Acute pancreatitis.
• D. Bud-Chiari syndrome.
• E. Splenic infarction.

BO5:7
• 7. The abdominal pain of acute mesenteric ischemia is characterized
by being:
• A. Proportional to physical findings.
• B. Out of proportion to physical findings.
• C. Aggravated by movements.
• D. Relieved by movements.
• E. Associated with fever.

BO5:8
• 8. Clues to acute mesenteric ischemia as a cause of acute abdominal
pain is the presence of:
• A. DVT.
• B. Recent abdominal surgery.
• C. AF &AMI.
• D. Presence of diagnosed thrombophilia.
• E. Male sex.

BO5:9
• 9. Clues to the chronic mesenteric ischemia as a cause of chronic
abdominal pain is the presence of all except:
• A. Immediate post-prandial pain.
• B. 30 mins post-prandial pain.
• C. Food fear.
• D. Weight loss.
• E. Female sex.

BO5:10
• 10. The serum marker suggesting severe acute mesenteric ischemia
is:
• A. Albumin.
• B. Trasferrin.
• C. Lactate.
• D. CRP.
• E. Transthretin.

BO5:10
• 10. Duplex ultrasound as diagnostic aid in mesenteric ischemia is
helpful best for:
• A. Acute mesenteric ischemia.
• B. Proximal disease.
• C. Distal disease.
• D. Chronic mesenteric ischemia.
• E. Obese patients.

BO5:11
• 11. The recommended imaging for the diagnosis of mesenteric
ischemic syndromes is:
• A. Duplex ultrasouns.
• B. CTA.
• C. MRA.
• D. Catheter angiography.
• E. Endoscopy.

BO5:12
• 12. The IVF volume requirements is more:
• A. Initially.
• B. In advanced disease.
• C. Before revascularization intervention.
• D. After revascularization intervention.
• E. None of the above.

BO5:13
• 13. Management of acute mesenteric ischemia include all except:
• A. IVF.
• B. Antibiotics.
• C. Vasodilators.
• D. Enteral feeding.
• E. Paranteral feeding.

BO5:14
• 14. The preferred approach for acute mesenteric ischemia is:
• A. Conservative management.
• B. Interventional radiology.
• C. Open surgery.
• D. Laproscopy surgery.

BO5:15
• 15. The preferred approach for chronic mesenteric ischemia is:
• A. Conservative management.
• B. Interventional radiology.
• C. Open surgery.
• D. Laproscopy surgery.

Introduction:
• Mesenteric ischemia is caused by blood flow insufficient to meet
the metabolic demands of the visceral organs.
• The severity & the type of organ involved depend on the affected
vessel& the extent of collateral-vessel blood flow.
• The most critical factor influencing outcomes is the speed of
diagnosis & intervention.
• Although uncommon cause of abdominal pain<1 of/1000 hospital
admissions, inaccurate or delayed diagnosis can result in
catastrophic complications & mortality among acute cases of 60-
80%.

Types:
• 1.Occlusive arterial disease: Arterial obstruction, most common;
acute &chronic forms.
• A. Acute mesenteric ischemia constitutes a surgical emergency:
• 1.Embolic occlusion in 40-50% of cases
• 2.Thrombotic occlusion of a previously stenotic mesenteric vessel in
20 -35%
• 3.Dissection or inflammation of the artery in <5%.

Types:
• B. Chronic mesenteric ischemia:
• 1.>90% related to progressive atherosclerotic disease of the origins
of the visceral vessels; treated with elective revascularization to
avert the risk of complications& death associated with the
development of acute ischemia.
• 2. Mesenteric venous thrombosis, accounts for 5-15%, results in
impaired venous outflow, visceral edema&abdominal pain,caused
by primary or idiopathic thrombosis& 90% of cases related to
thrombophilia, trauma, or local inflammation as pancreatitis,
diverticulitis, or inflammation or infection in the biliary system.
• Patients typically respond to anticoagulation in combination with
treatment for underlying local or systemic processes.
• Surgical intervention is reserved for patients who are critically ill or
whose condition is deteriorating; it is rarely required.

Types:
• 2. Non-occlusive mesenteric ischemia:
• it accounts for 5-15% of all cases of mesenteric ischemia,most often
associated with cardiac insufficiency or low-flow states after cardiac
surgery or hypovolemia or heart failure& hemodialysis.
• The mesenteric circulation is a high-resistance vascular bed in which
impaired regional perfusion owing to vasospasm can develop.
• The incidence of non-occlusive mesenteric ischemia may be
decreasing as awareness of the condition increases &supportive
therapies improve.

Pathophysiology:
• Mesenteric Circulation:
• Extremely complex.
• 3 primary vessels — the celiac artery, superior mesenteric artery, &
inferior mesenteric artery — interconnect through collateral
networks between the visceral & non-visceral circulations.
• These interconnections ensure that the loss of a single vessel does
not lead to catastrophic malperfusion of the viscera.
• The acute occlusion of a single vessel (typically the superior
mesenteric artery) in acute mesenteric ischemia can result in
profound ischemia caused by the loss of blood flow through this key
vessel & its collateral vascular network.
• In chronic mesenteric ischemia, additional collateral networks
develop over time; symptoms often do not appear until occlusion of
two or more primary vessels occurs.

Pathophysiology:
• Causes of altered mesenteric circulation:
• Often obstruction or diminished blood flow , with resulting hypoxia.
• Vasodilatation is the initial response, but prolonged ischemia leads
to vasoconstriction, which can persist even after intestinal blood
flow returns to normal.
• This early injury primarily affects the intestinal mucosa&submucosa
potentially impairs mechanisms that prevent the translocation of
bacteria from the intestinal lumen.
• Sequence of events result in the activation of systemic
inflammatory pathways & ultimately worsened vasospasm, further
regional ischemia& more extensive injury to the bowel wall.
• Without intervention, the damage can progress to full-thickness
injury, infarction & death.

History & PE:
• In contrast to other vascular disorders, mesenteric ischemia
primarily affects women; > 70% are female.
• The physician should assess the patient’s records& the results of
the examination for any evidence of other atherosclerotic &
vascular diseases, including PAD, cerebrovascular,CAD,
&renovascular disease.
• Other pulmonary &CV conditions must be identified & managed,
since they are often coexisting &may limit the available options for
revascularization.

History & PE:
• Features of acute mesenteric ischemia:
• May initially present with classic “pain out of proportion to
examination,” with an epigastric bruit; many, however, do not.
• Others may have tenderness with palpation owing to peritoneal
irritation caused by full thickness bowel injury.
• In a patient with abdominal pain of acute onset, it is critical to
assess the possibility of atherosclerotic disease&potential sources
of an embolus, including a history of AF &AMI.
• Patient’s description of the history & symptoms can be unclear
because of changes in mental status, particularly if elderly.
• Patients with mesenteric venous compared with acute arterial
occlusion, present with a less abrupt onset of abdominal pain.
• Risk factors for venous thrombosis: H/O deep venous thrombosis,
cancer, CLD or PVT, recent abd surgery, inflammatory disease &
thrombophilia.

History & PE:
• Features of chronic mesenteric ischemia:
• Can present with a variety of symptoms, including abd pain, PP
pain, nausea or vomiting (or both), early satiety, diarrhea or
constipation(or both)&weight loss.
• A detailed inquiry into the abd pain &relationship to eating can be
enlightening.
• Abdominal pain 30 - 60 minutes after eating is common&often self-
treated with food restriction, resulting in weight loss &in extreme
situations, fear of eating, or “food fear.”
• PP Pain DD: biliary disease,peptic ulcer disease, pancreatitis,
diverticular disease, gastric reflux, irritable bowel
syndrome&gastroparesis.

History & PE:
• An extensive GE workup, including even cholecystectomy , OGD&
lower endoscopy —often negative ,carried out before the diagnosis.
• An important distinction: these alternatives do not involve weight
loss, whereas it is common in cases of mesenteric ischemia.
• Since older age &H/O smoking are common in these patients,
cancer is often considered& may delay the identification of chronic
mesenteric ischemia.
• Particularly in the case of elderly women with a history of weight
loss, dietary changes& systemic vascular disease, chronic
mesenteric ischemia must be seriously considered&evaluated
appropriately.

Lab:
• Most useful in acute mesenteric ischemia are the assessment of
fluid, electrolyte, ABB& evaluation for infection.
• Many present with acidosis due to dehydration&decreased intake.
• Lactic acidosis often indicates at least segmental, severe ischemia or
irreversible bowel injury&not helpful to wait for evidence of
increasing serum lactate to proceed with further testing &
intervention would occur before lactic acidosis develops, with the
goal of saving additional intestine from full-thickness injury.
• A left shift neutrophils or high WBC may indicate full-thickness
injury to the bowel wall or ischemia with bacterial translocation.
• S. biomarkers not proved valuable for the early detection&no
clinically useful biomarkers, owing to the hepatic metabolism of
complex proteins secreted by the intestine.
• Nutritional status; albumin, transthyretin, transferrin, CRP, are the
only studies of value in cases of chronic mesenteric ischemia.

Imagings:
• Ultrasonography:
• Duplex U/S has a high degree of reliability & reproducibility, with
sensitivity/specificity of 85-90%.
• It is effective, low-cost, helpful in the assessment of the proximal
visceral vessels, but limited more distally.
• It is extremely operator dependent.
• Difficult to obtain in patients with obesity, bowel gas,heavy
calcification in the vessels,patients with acute mesenteric ischemia
because of the length of the study &abdominal pressure required;
so best reserved for the evaluation of patients with chronic
mesenteric ischemia& for monitoring after intervention.

Imagings:
• CTA: hs 95-100% accuracy, the recommended imaging for the
diagnosis of visceral ischemic syndromes, its benefits:
• Imaging origins&length of the vessels obtained rapidly
• Indicate extent of stenosis or occlusion.
• The relationship to branch vessels.
• Aid in the assessment of options for revascularization.
• indicate potential sources of emboli.
• Shows other intra-abd structures&pathologies as the lack of
enhancement or thickening of bowel wall &mesenteric stranding.
• Shows pneumatosis, free intraabdominal air, portal venous gas.
• CTA should be performed with IV contrast &reconstruction of
images with thin axial images (1-3 mm).
• Sensitivity of CTA is not as high for venous thrombosis,but improved
with two-phase imaging to enhance visceral venous drainage

Imagings:
• MRA: attractive option provide information about flow & avoid the
risks of radiation&use of contrast associated with CTA.
• It test takes longer to perform than CTA, lacks the necessary
resolution&can overestimate the degree of stenosis.
• Currently CTA imaging is almost always the preferred choice&its
advantages outweigh any risks.

Imagings:
• Endoscopy: most useful in diagnosing conditions other than
mesenteric ischemia as inflammatory&ischemic changes in the
stomach and proximal small bowel, rectum&right colon.
• Does not reach the majority of sections of the small bowel that are
most frequently involved in mesenteric ischemia.
• Only sensitive in identifying late changes, including infarction, but
lacks sensitivity / specificity in detecting more subtle ischemic
changes.

Imagings:
• Catheter angiography: usually for therapeutic intervention rather
than for diagnosis.
• Revascularization with selective catheterization of mesenteric
vessels, then single or complementary endovascular therapies,
including thrombolysis,angioplasty with or without stenting&
intraarterial vasodilation combined to restore blood flow.
• Angiography can also be used to confirm the diagnosis before open
abd exploration is undertaken.

Management:IVF,Electrolytes
• Fluid&Electrolyte Management:
• Fluid resuscitation with isotonic crystalloid&blood as needed.
• Serial monitoring of electrolytes& acid–base status should be
performed& invasive hemodynamic monitoring should be
implemented early especially in acute mesenteric ischemia, in
whom severe metabolic acidosis & hyperkalemia can develop as a
result of infarction with the potential for rapid decompensation to a
SIR or progression to sepsis.
• In hemodynamic instability; carefully adjust fluid volume while
avoiding fluid overload &pressor agents only as a last resort.
• The fluid-volume requirement can be very high, especially after
revascularization, because of the extensive capillary leakage; as
much as 10-20 liters of crystalloid fluid may be required during the
first 24 hours after the intervention.

Management:IVF,Electrolytes
• Early Medical Therapy:
• Heparin should be initiated as soon as possible in patients who
have acute ischemia or an exacerbation of chronic ischemia.
• Vasodilators may play a role in care, particularly in combating
persistent vasospasm in patients with acute ischemia after
revascularization.
• Bacterial translocation & sepsis develop& the high risk of infection
among outweighs the risks of antibiotic use, and therefore broad-
spectrum antibiotics should be administered early.
• Oral intake should be avoided in patients with acute mesenteric
ischemia, since it can exacerbate intestinal ischemia.
• In chronic mesenteric ischemia, enteral nutrition (as long as it does
not cause pain) or parenteral nutrition should be considered in
order to improve perfusion by means of mucosal vasodilation & to
provide nutritional&immunologic benefits.

Management:interventions
• Acute Mesenteric Ischemia: Endovascular interventions successful
in 87%, in-hospital mortality lower than open surgery (36% v 50%).
• This strategy may be most appropriate for patients with ischemia
not severe &those who have severe coexisting conditions that place
them at high risk for complications&death with open surgery.
• Most often mechanical thrombectomy or angioplasty & stenting.
• Thrombolysis is safe/effective in treating both embolic &
thrombotic occlusions& an adjunct to remove the additional burden
of thrombus in patients without peritonitis,especially helpful in
restoring perfusion to occluded arterial branches.
• 31% who received endovascular therapy were spared laparotomy.
• If endovascular-only therapy is pursued, close monitoring is
compulsory&any clinical deterioration or peritonitis necessitates
operative exploration as emergency as 28-59% will ultimately
require bowel resection.

• Acute Mesenteric Ischemia: Open Repair
• Emboli causing acute occlusion typically lodge within proximal SMA
have good response to surgical embolectomy.
• If embolectomy is unsuccessful, arterial bypass may be performed.
• If distal perfusion remains impaired, local intraarterial doses of
thrombolytic agents can be administered.
• A hybrid option, retrograde open mesenteric stenting, involves local
thromboendarterectomy& angioplasty, followed by retrograde
stenting,reduces the extent of surgery while allowing for direct
assessment of the bowel
• Short-term mortality after open revascularization ranges from 26-
65%, higher with renal insufficiency, older age, metabolic acidosis, a
longer duration of symptoms, and bowel resection at the time of a
second-look operation.

• Chronic Mesenteric Ischemia:
• Revascularization is indicated for all symptomatic patients.
• Now with endovascular repair, used in 70-80% of initial procedures.
• Stenting is used most often.
• Open repair can be performed with the use of antegrade inflow or
retrograde inflow (from the iliac artery), with either a vein or
prosthetic conduit to bypass one or more vessels, depending on the
extent of disease.
• Hybrid procedures involving open access to the superior mesenteric
artery &retrograde stenting, are also options.
• Endovascular therapy is a very successful,minimally invasive
approach that provides initial relief of symptoms in up to 95% & has
a lower rate of serious complications than open repair.

• Chronic Mesenteric Ischemia
• Despite these advantages, the use of endovascular techniques is
associated with lower rates of long-term patency &shorter time to
the return of symptoms,restenosis occurs in 40% & 20 - 50% will
require re-intervention.
• Open repair is associated with slower recovery & longer hospital
stays than endovascular repair.
• In most centers, endovascular therapy is considered to be first-line
therapy, particularly in patients with short, focal lesions,In contrast,
open repair may be a preferable option for younger, lower-risk
patients with a longer life expectancy.

• Venous Mesenteric Ischemia
• Unless such treatment is contraindicated, all patients should
initially receive heparin transitioned to long-term oral coagulation
24 - 48 hours after stabilization of the acute condition.
• 5% deteriorate, need transhepatic & percutaneous mechanical
thrombectomy, thrombolysis,open intraarterial thrombolysis.
• Any evidence of peritonitis, stricture, or GIB should trigger an
exploratory laparotomy to assess for the possibility of bowel
necrosis &need for a second-look operation.
• The long-term mortality is heavily influenced by the underlying
cause of thrombosis; 30-day survival is 80%&5-year survival is 70%.

• Nonocclusive Mesenteric Ischemia
• The outcomes depend on the management of the underlying cause;
overall mortality is 50-83%.
• The initial goal is to address hemodynamic instability to minimize
the use of systemic vasoconstrictors.
• Additional treatment may include systemic anticoagulation and the
use of vasodilators in patients who do not have bowel infarction.
• Catheter-directed infusion of vasodilatory&antispasmodic agents,
most commonly papaverine hydrochloride, can be used.
• Patients should be monitored closely by means of serial abdominal
examinations&open surgical exploration should be performed if
there is concern about the possibility of peritonitis.

Management:Follow-up
• Long-Term Care:
• Aggressive smoking-cessation measures, blood-pressure control&
statin.
• Lifelong preventive treatment with aspirin is recommended in all
patients who undergo endovascular or open repair.
• Patients who undergo endovascular repair should also receive
clopidogrel for 1 - 3 months after the procedure.
• Regardless of the type of repair performed, in patients with atrial
fibrillation, mesenteric venous thrombosis, or inherited or acquired
thrombophilia, oral anticoagulant therapy is indicated&should be
continued indefinitely or until the underlying cause of embolism or
thrombosis has resolved.

Management:Follow-up
• Long-Term Care:
• Nutritional status & body weight monitored in all patients who have
undergone an intervention for mesenteric ischemia.
• These patients may have prolonged ileus, food fear&require total
parenteral nutrition until full oral intake is possible.
• In bowel resection, diarrhea / malabsorption may occur.
• Extensive nutritional support, lifelong total parenteral nutrition, or
even evaluation for small-bowel transplantation may be required in
patients with persistent short-gut syndrome.
• Assessment:
• Lifelong repeated assessment of vascular patency is indicated.
Duplex ultrasonography should be performed every 6 months for
the first year after repair, then yearly thereafter.

Conclusion:
• Mesenteric ischemia is one of the least common causes of
abdominal pain, but associated with extremely high risk.
• Despite the variety of presentations & causes of mesenteric
ischemia, it always presents a diagnostic challenge&has the
potential for catastrophic, lifethreatening consequences.
• Early consideration&evaluation of this disease &underlying causes
in patients with abdominal pain are critical to timely diagnosis &
improved outcomes.

Git j club mesenteric ischemia nejm.

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