Endovascular Management of Ruptured Aortic Aneurysms: Emergency Protocols and Outcomes

Ruptured aortic aneurysm represents one of the most lethal surgical emergencies, with mortality rates exceeding 80% without intervention and approaching 50% even with traditional open surgical repair. The introduction of endovascular techniques for ruptured aneurysm management has transformed the treatment landscape, offering potential mortality benefits while reducing physiological stress in critically ill patients. This comprehensive review explores the evidence, protocols, technical considerations, and outcomes of endovascular repair for ruptured aortic aneurysms, providing healthcare professionals with essential knowledge for implementing and optimizing these life-saving approaches.

The Paradigm Shift in Ruptured Aneurysm Management

Historical Context and Evolution

From open surgery to endovascular approaches:

The management of ruptured aortic aneurysms has undergone a remarkable evolution over the past two decades. Traditionally, open surgical repair represented the only viable treatment option, requiring laparotomy, aortic cross-clamping, and surgical graft implantation—all in the setting of hemodynamic instability and coagulopathy. This approach carried mortality rates of 40-70% even in specialized centers, with particularly poor outcomes in elderly patients and those with significant comorbidities.

The first reported use of endovascular aneurysm repair (EVAR) for rupture occurred in the mid-1990s, demonstrating technical feasibility but leaving many questions regarding broader applicability and outcomes. Early adopters developed improvised protocols using devices and techniques designed for elective repair, with variable results reflecting the learning curve and lack of standardized approaches.

The subsequent two decades have witnessed progressive refinement of both technology and protocols specifically addressing the unique challenges of rupture scenarios. Purpose-designed devices with lower-profile delivery systems, simplified deployment mechanisms, and greater sizing flexibility have expanded anatomical eligibility. Simultaneously, specialized institutional protocols have evolved to address the logistical challenges of delivering complex endovascular care in emergency settings.

This evolution has shifted the paradigm from “EVAR when feasible” to “EVAR first” approaches in many centers with appropriate resources and expertise. Contemporary practice increasingly focuses not on whether endovascular repair should be attempted, but rather on optimizing systems to maximize the proportion of patients who can benefit from these techniques while minimizing delays to definitive treatment.

Physiological Rationale

Understanding the benefits beyond access:

The theoretical advantages of endovascular repair for ruptured aneurysms extend well beyond the obvious benefit of avoiding laparotomy, with several physiological mechanisms potentially contributing to improved outcomes:

Avoidance of aortic cross-clamping represents perhaps the most significant physiological advantage. Traditional open repair requires supraceliac or infrarenal clamping, causing profound hemodynamic disturbances including:
– Increased cardiac afterload and myocardial oxygen demand
– Ischemia-reperfusion injury to visceral organs and lower extremities
– Activation of inflammatory cascades
– Exacerbation of coagulopathy

Endovascular approaches instead utilize balloon occlusion only when necessary and for shorter durations, significantly reducing these physiological insults in already compromised patients.

Reduced blood loss contributes substantially to improved outcomes, as hemorrhage-induced coagulopathy represents a major driver of mortality in ruptured aneurysms. Endovascular techniques typically result in significantly lower blood loss compared to open surgery, with consequent reductions in transfusion requirements and associated complications including transfusion-related acute lung injury, immunomodulation, and hypothermia.

Attenuated systemic inflammatory response may improve outcomes through multiple mechanisms. Open surgical repair triggers profound inflammatory activation through exposure of blood to foreign surfaces, tissue trauma, and ischemia-reperfusion injury. This inflammatory surge can precipitate or exacerbate multiple organ dysfunction syndrome, particularly affecting pulmonary, renal, and cardiac function. The reduced inflammatory stimulus with endovascular repair may be particularly beneficial in elderly patients with limited physiological reserve.

Preservation of abdominal compartment integrity avoids the significant morbidity associated with abdominal compartment syndrome, which occurs in 10-20% of patients after open repair of ruptured aneurysms and carries mortality rates exceeding 70%. By avoiding disruption of tamponade from retroperitoneal hematoma and eliminating the need for laparotomy, endovascular approaches significantly reduce this devastating complication.

Emergency EVAR Protocols and Systems of Care

Institutional Preparedness

Creating systems for success:

Successful implementation of emergency endovascular programs requires comprehensive institutional preparation addressing multiple domains:

Infrastructure requirements include:
– 24/7 availability of appropriate imaging (CT scanners with rapid acquisition protocols)
– Hybrid operating rooms or angiosuites with full surgical capability
– Inventory of suitable endovascular devices spanning the range of anatomical variations
– Appropriate critical care facilities for postoperative management

Personnel considerations are equally important, requiring:
– Multidisciplinary teams including vascular surgeons, interventional radiologists, anesthesiologists, and specialized nursing staff
– Clear call schedules ensuring 24/7 availability of endovascular expertise
– Regular simulation training for both technical and non-technical aspects of emergency EVAR
– Engagement of emergency department staff in early recognition and activation protocols

Protocol development should address:
– Streamlined imaging pathways minimizing delays to intervention
– Permissive hypotension strategies for hemodynamically unstable patients
– Massive transfusion protocols coordinated with blood banks
– Standardized approaches to anesthesia induction and maintenance
– Clear decision algorithms for EVAR suitability assessment
– Defined conversion criteria and contingency planning

Quality improvement frameworks should include:
– Regular morbidity and mortality conferences reviewing all cases
– Outcome tracking with comparison to established benchmarks
– Process metrics focusing on time intervals (door-to-CT, CT-to-intervention)
– Feedback mechanisms to continuously refine protocols

Centers implementing comprehensive emergency EVAR programs consistently demonstrate improved outcomes compared to those offering only ad hoc capabilities, highlighting the importance of systematic preparation rather than isolated technical skills.

Patient Selection and Imaging

Balancing speed and precision:

Appropriate patient selection represents a critical determinant of outcomes in emergency EVAR, requiring rapid yet accurate assessment of both physiological status and anatomical suitability:

Hemodynamic assessment drives initial management, with patients broadly categorized as:
– Stable (systolic blood pressure >90mmHg without significant vasopressor support)
– Transient responders (initially responding to resuscitation but requiring ongoing support)
– Refractory shock (persistent hypotension despite resuscitation efforts)

These categories inform both the timing and approach to imaging, with stable patients typically undergoing standard CT protocols while those with greater instability may require abbreviated imaging or proceed directly to the operating room for proximal aortic control followed by intraoperative assessment.

Anatomical evaluation focuses on several key parameters affecting EVAR feasibility:
– Proximal neck length (≥10mm generally required, though shorter necks may be considered in extremis)
– Neck diameter and quality (severe angulation, conical shape, or thrombus may preclude emergency EVAR)
– Iliac access vessels (severe calcification, tortuosity, or stenosis may prevent device delivery)
– Involvement of visceral or renal arteries (requiring consideration of fenestrated or branched approaches in selected centers)

Imaging protocols have evolved to balance diagnostic accuracy with speed, typically employing:
– Non-contrast CT to confirm rupture and assess basic anatomical features
– CT angiography when hemodynamically tolerated to provide detailed measurements
– Focused protocols with reduced phases and limited coverage to minimize acquisition time
– Advanced post-processing available but not delaying intervention

The threshold for anatomical suitability often differs from elective settings, with many centers accepting more challenging anatomy given the poor prognosis with alternative approaches. This “rupture-specific” anatomical threshold recognizes that the risk-benefit calculation differs substantially from elective repair, with greater acceptance of potential long-term device-related complications in exchange for immediate survival benefit.

Permissive Hypotension and Anesthesia Considerations

Balancing perfusion and hemorrhage control:

Anesthetic management for ruptured EVAR requires specialized approaches addressing the competing priorities of maintaining vital organ perfusion while avoiding exacerbation of ongoing hemorrhage:

Permissive hypotension (or “hypotensive hemostasis”) has emerged as a key strategy, involving:
– Accepting systolic blood pressures of 70-90mmHg (or mean arterial pressures of 50-60mmHg) prior to aortic control
– Limiting fluid resuscitation to maintain consciousness and minimal organ perfusion
– Avoiding iatrogenic disruption of tamponade from retroperitoneal hematoma
– Immediate resuscitation once aortic control is achieved with endograft deployment

This approach contrasts with traditional trauma resuscitation paradigms but has demonstrated improved outcomes in both observational studies and animal models of aortic hemorrhage. Implementation requires close communication between all team members and careful titration of anesthetics to avoid precipitous blood pressure drops during induction.

Anesthetic technique selection remains controversial, with both general anesthesia and local anesthesia with sedation demonstrating advantages in different contexts:
– General anesthesia provides complete control of the airway and patient movement but may precipitate cardiovascular collapse during induction
– Local anesthesia with sedation avoids the hemodynamic perturbations of general anesthesia but may be challenging if patient cooperation is limited by pain or altered mental status
– Regional techniques (epidural, spinal) are generally avoided due to coagulopathy concerns and hemodynamic effects

Practical approaches often involve:
– Delayed intubation until immediately before incision when feasible
– Modified rapid sequence induction with reduced dosing of induction agents
– Vasopressor support immediately available during induction
– Consideration for local anesthesia with sedation in selected stable patients
– Preparation for immediate conversion to general anesthesia if needed

Intraoperative fluid management focuses on damage control resuscitation principles, including:
– Balanced blood product administration approximating whole blood ratios
– Limited crystalloid use to avoid dilutional coagulopathy
– Point-of-care coagulation testing to guide targeted factor replacement
– Permissive acidosis until hemorrhage control is achieved
– Aggressive rewarming to prevent hypothermia-induced coagulopathy

Technical Considerations and Adjunctive Procedures

Device Selection and Deployment Strategies

Adapting techniques for emergency settings:

Device selection and deployment techniques for ruptured EVAR require modifications from elective approaches, balancing the need for expedient deployment with adequate technical precision:

Device inventory considerations for emergency programs typically include:
– Modular bifurcated systems with various main body sizes
– Aorto-uni-iliac devices for challenging anatomy or expedited deployment
– Proximal extension cuffs for inadequate neck seal
– Large balloon-expandable stents for iliac conduits when needed
– Occlusion balloons for supraceliac control in extreme instability

Main body deployment strategies focus on:
– Precise positioning at the lowest renal artery to maximize seal in often short necks
– Limited or no contrast injections prior to deployment in extreme instability
– Consideration for deployment under fluoroscopic guidance alone when necessary
– Acceptance of potentially suboptimal positioning in extremis, with plan for later revision if needed

Contralateral limb cannulation often presents challenges in ruptured settings due to:
– Limited visualization from hemoperitoneum and ongoing hemorrhage
– Distorted anatomy from rupture and surrounding hematoma
– Time pressure in unstable patients

Techniques to address these challenges include:
– Use of stiff guidewires and supportive sheaths
– Buddy wire techniques to maintain access
– Consideration for aorto-uni-iliac configuration with femoro-femoral bypass when cannulation proves difficult
– Acceptance of “bailout” options including temporary deployment with planned secondary procedures

Balloon molding requires particular caution in rupture settings, with:
– Careful pressure monitoring during proximal neck ballooning
– Sequential rather than simultaneous ballooning when possible
– Consideration for compliant balloons at the proximal seal zone
– Awareness of increased risk of aortic injury in friable, ruptured tissue

Aortic Balloon Occlusion Techniques

Controlling catastrophic hemorrhage:

Resuscitative endovascular balloon occlusion of the aorta (REBOA) has emerged as a valuable adjunct in ruptured aneurysm management, providing temporary hemorrhage control while preparations for definitive repair are completed:

Indications for REBOA in ruptured aneurysm scenarios include:
– Profound hemodynamic instability precluding immediate CT imaging
– Cardiac arrest or peri-arrest situations
– Bridge to operating room availability
– Controlled induction of anesthesia in unstable patients

Technical approaches have evolved significantly, with current best practices including:
– Fluoroscopy-guided placement when possible, though blind placement may be necessary in extremis
– Positioning in the supraceliac aorta (Zone I) for maximal hemorrhage control
– Partial rather than complete occlusion when hemodynamics permit, reducing distal ischemia
– Intermittent deflation protocols to limit end-organ ischemia during prolonged use
– Specialized low-profile devices (7-9Fr) designed specifically for emergency use

Complications of REBOA require vigilant monitoring and management:
– Distal ischemia to extremities, spinal cord, and visceral organs
– Access site complications including bleeding and limb ischemia
– Balloon migration or rupture
– Aortic injury during placement or from prolonged inflation

Integration of REBOA into institutional protocols requires:
– Clear designation of which providers are credentialed for placement
– Standardized equipment sets immediately available in emergency departments
– Regular simulation training for all potential providers
– Defined protocols for maximum inflation times and deflation strategies

Management of Abdominal Compartment Syndrome

Addressing a lethal complication:

Abdominal compartment syndrome (ACS) remains a significant concern even with endovascular approaches, occurring in 5-10% of patients after ruptured EVAR (compared to 10-20% after open repair). Recognition and management of this complication is essential for optimizing outcomes:

Diagnostic criteria include:
– Sustained intra-abdominal pressure >20mmHg
– Associated with new organ dysfunction (typically oliguria, hypoxemia, or hypotension)
– Often accompanied by tense, distended abdomen on examination

Risk factors specifically relevant to ruptured EVAR include:
– Large retroperitoneal hematoma
– Massive transfusion requirements
– Prolonged hypotension
– Coagulopathy requiring packing for surgical sites
– Conversion from attempted endovascular to open repair

Prevention strategies focus on:
– Limiting crystalloid resuscitation
– Early correction of coagulopathy
– Maintaining adequate perfusion pressure
– Consideration for prophylactic open abdomen in highest-risk cases

Management approaches follow a stepwise progression:
– Medical management including nasogastric decompression, sedation, and neuromuscular blockade
– Percutaneous drainage of intraperitoneal fluid if present
– Surgical decompression with temporary abdominal closure for refractory cases

The threshold for decompressive laparotomy is typically lower than in other clinical scenarios given the catastrophic consequences of untreated ACS in this population. However, the procedure itself carries significant morbidity including enteroatmospheric fistula, massive ventral hernia, and prolonged hospitalization, requiring careful risk-benefit assessment for each patient.

Outcomes and Evidence Base

Салыстырмалы тиімділік

Evaluating the endovascular advantage:

The evidence comparing endovascular and open approaches for ruptured aneurysms has evolved substantially, from initial case series to randomized controlled trials and large observational studies:

Randomized controlled trials have provided important insights but demonstrate some limitations:
– The IMPROVE trial (largest RCT with 613 patients) showed no 30-day mortality difference between EVAR and open strategies (35.4% vs. 37.4%) but demonstrated significant survival advantage with EVAR at 3 years (54% vs. 42%)
– The AJAX and ECAR trials (smaller European RCTs) similarly showed no significant 30-day mortality differences
– All trials faced challenges with crossover between treatment arms and inclusion of patients ultimately found not to have rupture

Meta-analyses of randomized data suggest modest mortality benefits with EVAR (odds ratio 0.88 for 30-day mortality), though confidence intervals cross unity in most analyses. However, these studies consistently demonstrate reduced blood loss, shorter intensive care stays, and fewer major complications with endovascular approaches.

Large observational studies often demonstrate more substantial mortality benefits than randomized trials, with:
– Administrative database analyses showing 20-30% relative risk reductions in mortality with EVAR
– Single-center series from high-volume centers reporting mortality rates of 20-30% with emergency EVAR protocols
– Temporal trend analyses showing improved population-level outcomes correlating with increased EVAR utilization

This discrepancy between randomized and observational data likely reflects several factors:
– Selection bias in observational studies favoring EVAR for more stable patients
– Limited external validity of trials due to strict inclusion criteria
– Evolution of protocols and devices since trial completion
– Center expertise effects not captured in multicenter trials

The “EVAR first” strategy evaluated in the IMPROVE trial (immediate transfer to CT to assess EVAR suitability) demonstrated cost-effectiveness and long-term survival benefits compared to open-first approaches, supporting this as the preferred pathway when resources permit.

Predictors of Outcomes

Identifying factors affecting survival:

Multiple studies have identified key factors associated with outcomes after ruptured EVAR, providing guidance for patient selection and prognostication:

Pre-intervention factors associated with mortality include:
– Hemodynamic instability (particularly systolic blood pressure <70mmHg)
– Advanced age (>80 years)
– Loss of consciousness
– Cardiac arrest prior to intervention
– Elevated serum creatinine (>2.0 mg/dL)
– Low hemoglobin (<8 g/dL) suggesting significant blood loss

Anatomical factors affecting outcomes include:
– Aortic neck length <10mm
– Neck diameter >32mm
– Severe neck angulation (>60 degrees)
– Bilateral iliac aneurysms complicating distal seal

Procedural factors associated with improved outcomes include:
– Shorter time from presentation to intervention
– Performance in high-volume centers (>20 ruptured aneurysm repairs annually)
– Availability of dedicated emergency EVAR protocols
– Use of local anesthesia when feasible

These factors have been incorporated into several scoring systems attempting to predict mortality risk, including the Glasgow Aneurysm Score, Hardman Index, and Vancouver Score. While these tools demonstrate reasonable discrimination in development cohorts, their performance in external validation has been inconsistent, limiting clinical utility for individual patient decisions.

The most consistent predictor across multiple studies remains hemodynamic status, with profound or refractory shock carrying particularly poor prognosis regardless of repair technique. This observation has led some centers to question the benefit of intervention in patients with cardiac arrest or profound shock unresponsive to initial resuscitation, though others report salvage of selected patients even in these extreme circumstances.

Long-term Considerations

Beyond perioperative survival:

As immediate survival from ruptured aneurysm repair has improved, attention has increasingly focused on long-term outcomes and quality of life for survivors:

Reintervention rates after emergency EVAR exceed those for elective repair, with studies reporting:
– 15-30% reintervention within the first year
– Cumulative rates approaching 40-50% at 5 years
– Higher incidence of type I and III endoleaks compared to elective cases

Common indications for reintervention include:
– Type I endoleaks from suboptimal seal in challenging anatomy
– Type II endoleaks with aneurysm growth
– Limb occlusion or stenosis
– Access site complications requiring repair
– Late rupture (occurring in 2-5% of cases)

Despite these reintervention rates, long-term survival data from the IMPROVE trial demonstrated sustained benefit of the endovascular strategy, with significantly improved 3-year and 7-year survival compared to open repair. This finding suggests that the perioperative physiological benefit of EVAR translates to long-term survival advantage despite the burden of surveillance and reinterventions.

Quality of life outcomes increasingly factor into evaluation of emergency EVAR, with studies showing:
– Faster return to baseline function compared to open repair
– Similar long-term quality of life between survivors of open and endovascular repair
– Substantial proportion of patients (>70%) living independently at one year
– Age-appropriate quality of life scores by 6-12 months post-intervention

These findings support aggressive intervention even in elderly patients, as those surviving the perioperative period typically regain good functional status and quality of life, challenging nihilistic approaches based solely on chronological age.

Медициналық жауапкершіліктен бас тарту

Маңызды ескерту: This information is provided for educational purposes only and does not constitute medical advice. Ruptured aortic aneurysm represents a life-threatening emergency requiring immediate medical attention. The management approaches discussed should only be implemented by qualified healthcare professionals with appropriate training and expertise in vascular emergencies. Individual treatment decisions should be based on patient-specific factors, current clinical guidelines, and physician judgment. If you experience symptoms suggestive of aortic rupture (severe abdominal or back pain, syncope, or hypotension), seek emergency medical care immediately. This article is not a substitute for professional medical advice, diagnosis, or treatment.

Қорытынды

Endovascular repair has transformed the management landscape for ruptured aortic aneurysms, offering improved outcomes through reduced physiological stress in these critically ill patients. The evolution from isolated case reports to comprehensive institutional protocols represents one of the most significant advances in vascular emergency care over the past two decades.

Current evidence supports an “EVAR first” strategy when anatomically suitable and institutionally feasible, with particular benefit for elderly patients and those with significant comorbidities. Implementation requires comprehensive institutional preparation addressing infrastructure, personnel, protocols, and quality improvement frameworks rather than simply technical capability.

The future of ruptured aneurysm management likely involves further refinement of patient selection, development of rupture-specific devices, and integration of advanced adjuncts including REBOA and artificial intelligence for rapid decision support. As these advances continue, the historically dismal prognosis of this condition continues to improve, offering hope to patients facing one of vascular surgery’s most lethal emergencies.