Abdominal Compartment Syndrome and Visceral Venous Disorders

Abdominal Compartment Syndrome: Background

Definition and key concepts

Abdominal compartment syndrome (ACS) is sustained intra-abdominal hypertension (IAH) associated with new organ dysfunction/failure. ACS is commonly defined as IAP >20 mmHg plus new organ dysfunction, although clinically important deterioration may occur at lower pressures depending on baseline abdominal compliance and cardiopulmonary reserve. (Kirkpatrick 2013)📄 (Malbrain 2006)

IAH is frequent in critically ill and post-operative patients; therefore, screening and serial measurement in high-risk populations (e.g., ruptured 4Aneurysms, damage-control laparotomy, major trauma, pancreatitis, massive transfusion/resuscitation) is a key prevention strategy. (Kirkpatrick 2013)📄 (Bj 2016)📄

WSACS IAH grading

Epidemiology and outcomes

• IAH/ACS is encountered after major vascular and trauma surgery, particularly after ruptured 4Aneurysms repair and damage-control abdominal surgery. (Bj 2016)📄 (Kirkpatrick 2013)📄
• Mortality increases substantially when ACS is unrecognized or decompression is delayed, reflecting progression from potentially reversible physiologic compromise to established organ failure. (Malbrain 2006) (Kirkpatrick 2013)📄

ACS: Etiology and Risk Factors

Primary Causes (directly increase intra-abdominal volume):

• Massive intra-abdominal bleeding (ruptured 4Aneurysms, trauma)
• Retroperitoneal hematomas
• Severe acute pancreatitis
• Bowel obstruction or ileus
• Mesenteric ischemia with bowel edema
• Abdominal packing for damage control surgery

Secondary Causes (increase abdominal contents without primary pathology):

• Aggressive fluid resuscitation (capillary leak, bowel wall edema)
• Sepsis with third-spacing
• Major burns with massive resuscitation
• Post-cardiac surgery with fluid overload

Risk Factors:

• Large-volume crystalloid resuscitation (>3.5 L in 24 hours)
• Massive transfusion protocol activation
• Coagulopathy requiring blood product replacement
• Hypothermia (<34°C)
• Prolonged operative time (>6 hours)
• Damage control surgery with temporary abdominal closure
• Postoperative bleeding or re-exploration (Kirkpatrick 2013)📄

ACS: Pathophysiology

Elevated intra-abdominal pressure causes multi-system organ dysfunction through direct mechanical effects and secondary hypoperfusion.

Cardiovascular Effects:

• Impaired venous return from IVC compression → decreased preload
• Increased systemic vascular resistance → increased afterload
• Net result: decreased cardiac output despite adequate volume status
• Abdominal perfusion pressure (APP = MAP − IAP) reflects organ perfusion; target APP ≥60 mmHg (Cheatham 2000)

Respiratory Effects:

• Cephalad displacement of diaphragm → reduced lung compliance
• Decreased functional residual capacity → atelectasis
• Impaired gas exchange → hypoxemia and hypercarbia
• Elevated peak inspiratory pressures on mechanical ventilation

Renal Effects:

• Direct compression of renal parenchyma and vasculature
• Reduced renal perfusion pressure and glomerular filtration
• Oliguria progressing to anuria
• APP-targeted resuscitation improves renal outcomes

Gastrointestinal Effects:

• Splanchnic hypoperfusion → mucosal ischemia
• Intestinal barrier failure → bacterial translocation
• Endotoxemia and systemic inflammatory response
• Hepatic congestion and dysfunction

Neurological Effects:

• Impaired cerebral venous drainage → elevated intracranial pressure
• Relevant in patients with concomitant traumatic brain injury (Kirkpatrick 2013)📄

ACS: Clinical Presentation and Diagnosis

When to suspect and monitor for IAH/ACS

Measure intra-abdominal pressure (IAP) in patients with new or worsening organ dysfunction and risk factors such as major hemorrhage, massive transfusion, large-volume resuscitation, damage-control laparotomy/packing, severe pancreatitis, bowel obstruction/ileus, or tense ascites. (Kirkpatrick 2013)📄 (Malbrain 2006)

Typical clinical features (nonspecific—do not rely on exam alone)

• Increasing ventilatory pressures and worsening oxygenation/CO₂ clearance. (Kirkpatrick 2013)📄
• Oliguria/anuria and rising creatinine. (Kirkpatrick 2013)📄
• Hypotension or escalating vasopressor requirement despite resuscitation. (Kirkpatrick 2013)📄
• Rising lactate/metabolic acidosis (often late). (Kirkpatrick 2013)📄

Transvesical (bladder) IAP measurement (WSACS standard)

Transvesical measurement is the reference bedside technique. (Kron 1984)📄 (Kirkpatrick 2013)📄

1. Place the patient supine.
2. Measure at end-expiration.
3. Zero the transducer at the mid-axillary line (iliac crest level).
4. Instill ≤25 mL sterile saline into the bladder.
5. Allow 30–60 seconds for equilibration.
6. Record IAP in mmHg and trend over time.

Interpretation and diagnostic threshold

• IAH: sustained IAP ≥12 mmHg. (Kirkpatrick 2013)📄
• ACS (typical threshold): sustained IAP >20 mmHg with new organ dysfunction/failure. (Kirkpatrick 2013)📄
• Consider the trajectory (rising IAP with worsening physiology) and the abdominal perfusion pressure concept (APP = MAP − IAP) when prioritizing resuscitation goals. (Cheatham 2000) (Kirkpatrick 2013)📄

Suggested monitoring frequency

• High-risk patients: q4–6 hours (or more often during rapid physiologic change). (Kirkpatrick 2013)📄
• Continue until IAP normalizes and risk factors resolve. (Kirkpatrick 2013)📄

Role of imaging

CT can identify contributors (hemorrhage, bowel edema/obstruction, pancreatitis complications, ascites) and may show indirect features (compressed IVC, 'rounded' abdomen), but CT does not establish ACS without corroborating IAP and organ dysfunction. (Kirkpatrick 2013)📄

ACS: Stepwise Management Algorithm

Management is cause control + staged IAP reduction, escalating rapidly when organ dysfunction progresses. A stepwise approach is recommended. (Kirkpatrick 2013)📄

Bedside management bundle (start immediately when IAH/ACS suspected)

Escalation to operative decompression

Proceed to decompressive laparotomy when:

• IAP remains elevated (commonly >20 mmHg) with new/progressive organ dysfunction despite optimization, or
• There is rapid physiologic collapse where delay risks irreversible organ injury. (Kirkpatrick 2013)📄 (Bj 2016)📄

Early decompression requires planning for temporary abdominal closure and subsequent open abdomen strategy (see 'Open Abdomen Management'). (Coccolini 2018)📄

ACS: Decompressive Laparotomy

Indications:

• Sustained IAP >20 mmHg with organ dysfunction despite medical optimization
• Rapidly deteriorating clinical status with hemodynamic collapse
• Refractory respiratory failure with elevated airway pressures
• Progressive renal failure (oliguria/anuria)
• Worsening metabolic acidosis

Technique:

• Full midline laparotomy from xiphoid to pubis
• Complete fascial release along entire length
• Inspect abdominal contents for source control
• Temporary abdominal closure required

Timing:

• Do not delay in patients with obvious ACS and hemodynamic collapse
• Prolonged ACS leads to irreversible organ injury
• Each hour of delay increases mortality (Kirkpatrick 2013)📄

Role of Endovascular Adjuncts:

• resuscitative endovascular balloon occlusion of the aorta (REBOA) may be used as a bridge to hemorrhage control in ruptured 4Aneurysms or trauma (see 16EVTM) (Bulger 2019)📄
• These interventions do NOT treat IAH/ACS
• If ACS criteria persist after endovascular hemorrhage control, decompressive laparotomy remains necessary

ACS: Open Abdomen Management

Temporary Abdominal Closure Techniques:

• Negative pressure wound therapy (NPWT) is preferred
• Visceral protection with non-adherent barrier layer is essential
• Options: VAC devices, ABThera system, Barker vacuum pack

Dynamic Fascial Traction:

• Progressive approximation of fascial edges
• Use sutures, vessel loops, or commercial devices
• Tighten incrementally every 24–48 hours as edema resolves
• Significantly improves primary fascial closure rates

Goals:

• Achieve primary fascial closure within 4–7 days when physiology permits
• Delayed closure beyond 7–10 days has decreased success rates

Nutritional Support:

• Initiate early enteral nutrition within 24–48 hours when feasible
• Maintains gut barrier function and reduces infectious complications
• Parenteral nutrition if enteral route not feasible

Prevention of Enteroatmospheric Fistula:

• Maintain adequate visceral coverage at all times
• Minimize direct bowel-to-wall contact
• Avoid excessive negative pressure
• Careful dressing changes to prevent mechanical trauma

Staged Re-exploration:

• Plan serial operations every 24–48 hours
• Remove necrotic tissue, reassess bowel viability, irrigate
• Continue until source control achieved and closure possible (Coccolini 2018)📄

Visceral Venous Disorders: Overview

Visceral venous disorders include thrombosis and obstruction of the portal, mesenteric, and hepatic venous outflow systems. Presentations range from incidental imaging findings to life-threatening intestinal ischemia or acute liver failure. (Plessier 2012)

Practical classification (guides urgency and therapy)

• Acute vs chronic (collateralization/cavernous transformation suggests chronicity). (Plessier 2012)
• Cirrhotic vs non-cirrhotic (risk/benefit balance of anticoagulation differs). (Plessier 2012)
• Malignant vs bland thrombosis (tumor invasion generally does not recanalize with anticoagulation alone). (Plessier 2012)
• Isolated vs extensive (e.g., portal + SMV involvement increases bowel ischemia risk). (Plessier 2012)

Initial evaluation (shared approach)

1. Confirm extent with appropriate imaging (Doppler US, contrast CT portal venous phase, or MR venography). (Plessier 2012)
2. Assess for end-organ threat:
3. - Peritonitis/ischemia → urgent surgical evaluation (especially with mesenteric involvement). (Bala 2017)📄 (Clair 2016)
4. - Acute liver failure/refractory ascites/variceal bleeding → hepatology + interventional evaluation. (Darwish Murad 2004)📄
5. Identify provoking factors and systemic risks (infection/inflammation, recent surgery, malignancy, myeloproliferative disease, thrombophilia). (Plessier 2012) (Heit 2015)📄

Anticoagulation principles

When not contraindicated, therapeutic anticoagulation is the cornerstone for most acute bland splanchnic venous thromboses; agent selection and duration should be aligned with general venous thromboembolism (VTE) guidance and individualized to hepatic function and bleeding risk. (Kearon 2016) (Ortel 2020)📄

Portal Vein Thrombosis

Definition and clinical phenotypes

Portal vein thrombosis (PVT) may be:

• Acute (new clot, abdominal pain, fever, ileus; higher risk of extension into the superior mesenteric vein (SMV) with intestinal ischemia). (Plessier 2012)
• Chronic (portal hypertension, varices, splenomegaly, cavernous transformation). (Plessier 2012)

Also distinguish:

• Bland vs malignant PVT (tumor invasion—most commonly hepatocellular carcinoma—changes expectations for recanalization and overall strategy). (Plessier 2012)
• Cirrhotic vs non-cirrhotic PVT (different bleeding risk profile and competing risks). (Plessier 2012)

Diagnosis

• Doppler ultrasound is first-line (absent flow, echogenic material, collateralization/cavernoma). (Plessier 2012)
• Contrast CT (portal venous phase) defines extent (portal confluence, SMV involvement) and evaluates bowel perfusion and alternate diagnoses. (Plessier 2012)
• MR venography is an alternative when iodinated contrast is unsuitable. (Plessier 2012)

Treatment goals

• Prevent extension/recurrence.
• Promote recanalization in selected acute cases.
• Manage portal hypertension sequelae (varices/ascites) in chronic disease. (Plessier 2012)

Anticoagulation (core therapy for acute bland PVT)

• Start therapeutic anticoagulation when acute bland PVT is diagnosed and bleeding risk is acceptable, particularly if there is extension toward the SMV, symptoms, or a strong prothrombotic driver. (Plessier 2012) (Kearon 2016)
• Agent selection (low-molecular-weight heparin (LMWH), vitamin K antagonist (VKA), or direct oral anticoagulant (DOAC)) and duration should follow general venous thromboembolism (VTE) principles while considering liver function, drug interactions, and gastrointestinal (GI) bleeding risk. (Kearon 2016) (Ortel 2020)📄
• In patients with cirrhosis, DOACs have demonstrated comparable safety and potentially superior recanalization rates compared to VKAs. (Dai 2026)
• Duration is commonly at least 3–6 months, with longer therapy considered for persistent risk factors or recurrence. (Kearon 2016)

Endovascular and portal decompressive options

• Consider a transjugular intrahepatic portosystemic shunt (TIPS) when portal hypertension complications are refractory to standard therapy or when recanalization is needed to facilitate portal inflow, especially in liver transplant candidates. (Plessier 2012) (Dai 2026)
• Catheter-directed thrombolysis/thrombectomy is reserved for highly selected patients with extensive acute thrombosis and threatened bowel, typically in specialized centers. (Plessier 2012)

Surgery

• If intestinal infarction develops (typically from SMV extension), urgent exploration and bowel resection are required (see 11Mesenteric Ischemia principles). (Bala 2017)📄 (Clair 2016)

Mesenteric Vein Thrombosis

Mesenteric vein thrombosis (MVT), most often involving the superior mesenteric vein, accounts for a minority of acute mesenteric ischemia presentations but carries substantial morbidity when diagnosis is delayed. (Acosta 2010) (Clair 2016)

Clinical presentation

• Often subacute abdominal pain over days (sometimes weeks), frequently less abrupt than arterial occlusion. (Clair 2016)
• Nausea/vomiting/diarrhea; GI bleeding may occur.
• Peritonitis or shock suggests transmural infarction and mandates urgent operative evaluation. (Bala 2017)📄 (Clair 2016)

Diagnosis

CT with portal venous phase is the imaging test of choice to confirm venous thrombosis and assess bowel viability (edema, mesenteric congestion, pneumatosis, free fluid). (Bala 2017)📄 CT is highly accurate for acute mesenteric ischemia evaluation in general, supporting its central role when ischemia is a concern. (Menke 2010)📄

Management (decision framework)

1. No peritonitis / no infarction on imaging (most patients)
2. - Immediate therapeutic anticoagulation (e.g., IV unfractionated heparin or LMWH), bowel rest, supportive care, and close reassessment. (Bala 2017)📄 (Kearon 2016)
3. Peritonitis, perforation, or infarction suspected/confirmed
4. - Exploratory laparotomy with resection of non-viable bowel; consider second-look laparotomy when viability is uncertain. (Bala 2017)📄 (Clair 2016)
5. Selected extensive acute thrombosis without peritonitis (center-dependent)
6. - Consider catheter-directed thrombolysis/thrombectomy in specialized centers when there is threatened bowel but no established infarction. (Brandt 2015)📄 (Kumar 2001)

Budd-Chiari Syndrome

Budd–Chiari syndrome (BCS) is hepatic venous outflow obstruction (hepatic veins and/or suprahepatic IVC), causing hepatic congestion, portal hypertension, and progressive liver dysfunction. (Darwish Murad 2004)📄

Diagnosis

• Doppler ultrasound is typically first-line to identify absent/reversed hepatic venous flow and IVC abnormalities. (Darwish Murad 2004)📄
• CT/MR helps define anatomy (hepatic vein/IVC obstruction), hepatic congestion patterns, and alternate diagnoses. (Darwish Murad 2004)📄
• Venography is used when detailed anatomy is needed for intervention planning (angioplasty/stenting or TIPS). (Darwish Murad 2004)📄

Management (step-up strategy)

Etiology workup (do not omit)

Evaluate for prothrombotic disorders (especially myeloproliferative neoplasms), antiphospholipid syndrome, and inherited thrombophilia; management often requires coordinated hematology/hepatology care. (Darwish Murad 2004)📄 (Heit 2015)📄

Surveillance and Long-term Management

Abdominal Compartment Syndrome:

• Continue IAP/APP monitoring until values normalize
• After temporary closure: plan primary fascial closure within 4–7 days
• If fascial closure not achieved: planned ventral hernia with delayed reconstruction
• Long-term: abdominal wall reconstruction may be required (Coccolini 2018)📄

Portal Vein Thrombosis:

• Anticoagulation duration: minimum 3–6 months; consider lifelong if:
  • Underlying thrombophilia identified
  • Cirrhosis present
  • Recurrent thrombosis
• Imaging surveillance: Doppler US at 3 and 6 months to assess recanalization
• Variceal screening: upper endoscopy if portal hypertension develops
• Thrombophilia workup if no obvious etiology (see 12VTE) (Plessier 2012)

Mesenteric Vein Thrombosis:

• Lifelong anticoagulation generally recommended given high recurrence risk
• Follow-up imaging at 3–6 months
• Monitor for short bowel syndrome if resection performed
• Screen for underlying malignancy or thrombophilia (Kumar 2001)

Budd-Chiari Syndrome:

• Lifelong anticoagulation for most patients
• Surveillance imaging (CT or MRI) every 6–12 months
• Monitor liver function tests regularly
• TIPS surveillance: Doppler US every 6 months for patency
• Screen and treat underlying myeloproliferative neoplasms
• Variceal surveillance and management per portal hypertension guidelines
• Liver transplant evaluation if progressive hepatic decompensation (Darwish Murad 2004)📄

Guidelines and Evidence

Abdominal Compartment Syndrome (ACS)

• WSACS consensus definitions and clinical practice guidance for IAH/ACS. (Kirkpatrick 2013)📄
• WSES guideline for open abdomen management (temporary abdominal closure, re-exploration timing, closure strategy). (Coccolini 2018)📄
• Vascular surgery–relevant perspective on ACS recognition/management after major vascular procedures. (Bj 2016)📄

Visceral venous disorders / venous thrombosis principles

• CHEST guideline framework for anticoagulation duration and strategy (apply with liver-specific bleeding risk considerations). (Kearon 2016)
• ASH venous thromboembolism (VTE) treatment guideline (agent selection and treatment phases; apply with hepatic function considerations). (Ortel 2020)📄

Mesenteric ischemia and mesenteric venous thrombosis (MVT)

• WSES acute mesenteric ischemia guideline (operative thresholds, imaging-first strategy, and decision-making). (Bala 2017)📄
• ACG clinical guideline on intestinal ischemia (diagnostic and management principles relevant to venous ischemia presentations). (Brandt 2015)📄
• Review-level synthesis for acute mesenteric ischemia (context and clinical patterns). (Clair 2016)