Ruptured Abdominal Aortic Aneurysms

Eliza Long

Treatment of the Ruptured Abdominal Aortic Aneurysm

• Diagnosis– Clinical– Imaging

• Resuscitation

• Surgery– Different options

• Complications

DiagnosisClinical Presentation

• “Classic triad:”– Severe abdominal pain– Hypotention

• An episode of syncope may be a hint

– Pulsatile mass• Large girth may obscure

• Less common symptoms:– Groin/flank pain, hematuria, groin hernia all secondary

to increased intra-abdominal pressure– Congestive Heart Failure with JVD and abdominal bruit

if patient has ruptured into the Vena Cava

14 x 8 cm abdominal aortic aneurysm arising from the supraceliac aorta and extending to just above the take off of the left renal artery is visualized with extensive thrombus but also extensive flow

– RAAA is misdiagnosed 16% - 30% of the time• Common misdiagnosis:

– Renal colic, perforated viscous, diverticulitis, gastrointestinal hemorrhage and ischemic bowel

– Mortality rates for correctly diagnosed was 58%, and 44% for misdiagnosed

• Likely due to fact that less severe ruptures have a more subtle presentation and can survive longer before going to OR

DiagnosisClinical Presentation

DiagnosisImaging

• Plain Films– Enlarged outline of calcified aortic wall

• A retrospective review showed that 65% of x-rays form RAAA had calcified aortic wall

– Loss of psoas shadow

• Abdominal U/S– Sensitive in detecting aneurysm but not in detecting rupture

• Abdominal CT– Most accurate method– See presence of retroperitoneal blood (77% sensitive and

100% specific)

Enlarged outline of calcified aortic wall

Loss of psoas shadow

Sensitive in detecting aneurysm but not in detecting rupture

See presence of retroperitoneal blood. Here there is not a large retroperitoneal hematoma, but stranding of blood into surrounding tissues

Resuscitation

• If suspecting rAAA:– 2 Large bore IVs

– Type and Cross for at least 6 Units of pRBCs

• Confirmed rAAA:– Transfer to Operating room (transfer to center with

experienced surgeons prepared for rAAA)

– Establish art line and foley

– Prep and drape before and during anesthetic induction

Resuscitation

• Actual Pre-Op resuscitation– Controversial

• Aggressive crystalloid can elevate BP and cause rupture of temporary aortic seal that forms after initial rupture

• Minimally resuscitate to “maintain conconsciousness” (~80 systolic) and use blood

• No randomized trials testing the different degrees of resuscitation with rAAA

– Animal studies show increased mortality when resuscitation occurs before control of hemorrhage

Surgery

• OPEN TRANSPERITONEAL

• OPEN RETROPERITONEAL

• ENDOVASCULAR

SurgeryOpen Repair

Hypotension

Pararenal Extensive Hematoma

Inspect Retroperitoneum Reflect bowel and duodenum

Uncontrolled Bleeding Develops

Supraceliac Clamp

Careful Dissection for InfrarenalInfrarenal Control

No Hypotension

No Hematoma

SurgeryOpen Repair TRANSPERITONEAL

• Transperitoneal allows the fastest and easiest approach for Supraceliac clamp

• Retract the left lobe of the liver to right to show supraceliac aorta at diaphragm

• NG tube identifies esophagus and proximal stomach and retracts to the left

• Enter lesser sac by opening gastrohepatic omentum

• Aorta is found between crura of diaphragm and is clamped– Can reposition clamp to infrarenal neck of aneurysm once

aneurysm is opened

– or can make first anastamosis in aneurysm sac and then transfer clamp to graft to reperfuse kidneys and viscera.

Retract the left lobe of the liver to right to show supraceliac aorta at

diaphragmNG tube identifies esophagus

and proximal stomach and retracts to the left

Enter lesser sac by opening gastrohepatic omentum

Sometimes crura may need to be split with electrocautery for

appropriate visualization

Aorta is found between crura of diaphragm and is

clamped

Supraceliac Clamp– Coordinate with anesthesia

• after clamp “crank up” the resuscitation• before releasing supraceliac clamp prepare for hypotension

– Advantages • quick solution to severe hypotension from intraperitioneal

rupture.• avoids injury to renal and gonadal vein injury from blind

dissection of infrarenal neck

– Disadvantage • ischemic injury injury to liver, bowel, and kidneys

SurgeryOpen Repair TRANSPERITONEAL

SurgeryOpen Repair RETROPERITONEAL

• ESPECIALLY for pararenal or suprarenal RAAA

• 10th interspace incision – 1) Left colon mobilized to incise lateral peritoneal attachments.

– 2) Colon, pancreas, spleen, and kidney are elevated access diaphragmatic crura.

– 3) Divide crura access entire intra-abdominal aorta and visceral and renal vessels

– 4) May need a thoracoabdominal incision, or extra thoracic incision for the larger people, or the hostile abdomen

SurgeryOpen Repair Extras

• Brachial/femoral cut-down for occlusive balloon into aorta

• Aortic compressor to supraceliac aorta if rapid control needed before establishing exposure for clamp

• Aortocaval fistula direct digital pressure above and below the fistula and suture of the fistula from within the sac

• If iliac aneurysms are present leave alone unless ruptured, if so repair easiest first (allow for pelvic reperfusion)

• Use cellsaver, its use is justified if anticipate large blood loss

Aortic compressor to supraceliac aorta if rapid control needed

before establishing exposure for clamp

SurgeryOpen Repair Anatomic abnormalities

• Venous anomalies that can cause bleeeding during clamping:– Retroaortic renal vein

– Circumaortic renal vein

– Left-sided vena cava

– Duplicate inferior vena cava

• Horseshoe kidney– If at neck of aneurysm it prevents adequate exposure (another

reason to perform supraceliac clamping)

– Isthmus often contains renal tissue, collecting system and blood supply

• If known before surgery, retroperitoneal approach

SurgeryOpen Repair

• Closing– 25%-30% cases, the abdomen cannot be closed without significant

tension from swollen bowel or retroperitoneal hematoma• Abdominal compartment syndrome (ACS) is bladder presser > 30cm

H2O or 25mm Hg

• Use early mesh to reduce incidence of multi organ failure from ACS – Especially with pre-op anemia, prolonged shock, pre-op cardiac shock,

pre-op cardiac arrest, massive resuscitation, profound hypothermia, or severe acidosis

• Use nonabsorbable mesh covered with plolyurethane

• Early mesh closure vs takeback mesh resulted in 6% and 40% colon ischemia respectively

• Institution requirements:– 1) Rapid CT scanning

• For neck diameter, angulation, and iliac size

• Only about 20-46% of rAAA are suitable for EVAR

– 2) Training– 3) Devices– 4) Suite for Endovascular procedure

SurgeryEndovascular Repair

• Stratagies for Repair:– Aorto-unifemoral graft ipisalateral internal

iliac exclusion and a femorofemoral crossover graft (Montefiore group)

– Modular aortouniiliac and aortobiiliac

• Now rupture kits for repair

SurgeryEndovascular Repair

Endovascular Grafts and Other Image-Guided Catheter-Based Adjuncts to Improve the Treatment of Ruptured Aortoiliac AneurysmsTakao Ohki and Frank J. VeithAnn Surg. 2000 October; 232(4): 466–479.

Aorto-unifemoral graft

Early Experience with the Talent™ Stent-Graft System for Endoluminal Repair of Abdominal Aortic AneurysmsFrank J. Criado, MD, Eric P. Wilson, MD, Eric Wellons, MD, Omran Abul-Khoudoud, MD, and Hari Gnanasekeram, MD Tex Heart Inst J. 2000; 27(2): 128–135.

Modular aortouniiliac and aortobiiliac

• Anesthesia– Can use local (unless patients are squirming)

• Don’t loose the sympathetic tone that can maintain pressure

• Some start under local and convert to general for positioning and release of graft

SurgeryEndovascular Repair

• Mortality Rates 10% to 45%, but limited numbers of patients

• Causes – Colon ischemia– MOF– Continued hemorrage

• Endoleaks are a much bigger problem in this setting as hemorrhage isn’t controlled

SurgeryEndovascular Repair

Table 102-1. Reported Data on Ruptured Abdominal Aortic Aneurysms (RAAA) Treated by Endovascular Aneurysm Repair

FIRST AUTHORRAAA RE-

EVALUATED (no.)EVAR

COMPLETED (%)EVAR

MORTALITY (%)CONVERSION

RATE (%)

Ohki, 200154 25 100 10 20

Hinchliffe, 20019 20 85 45 15

Lachat, 200255 57 37 9.5 0

Orend, 200239 21 71 14 29

Resch, 200394 21 100 19 0

Scharrer-Pamler, 200395

24 100 12.5 4

Peppelenbosch, 200352

40 65 15 0

Reichart, 200323 25 23 17 0

Totals 219 71 18 8.5

 

ComplicationsLocal

• Postoperative bleeding related to coagulapathy from hypothermia (12%-14%)

• Limb ischemia embolization from aortic debris, or clot formed in illiacs if retrograde flushing is not performed

• Colonic ischemia (3%-13%) leads to mortality in 73%-100% of time– Degree and duration of hypotension

– Patency of IMA

– Collateral supply

– Site of hematoma

• Spinal Cord Injury: incidence 2.3%. – Interuption of pelvic blood supply, prolonged aortic cross-clamping,

introperative hypotension, aortic embolization, internal iliac interuption

ComplicationsSystemic

• Respiratory Failure – 26-47% (mortality up to 68%) – High O2 requirements, increased lung permeability, decrease in

lung compliance– Factors that predispose

• Large shifts in fluid and blood• Pre-existing pulmonary dysfunction• Long cross-clamp time

• Renal Dysfunction – Incidence is 26-42% in patients in symptomatic aneurysms or

rAAA– Higher with suprarenal cross-clamp, longer duration of cross-

clamp, pre-existing renal dysfunction, shock, old age

ComplicationsSystemic

• Irreversible Shock – 10-15% of rAAA mortality

– Irreversible state in which aortic clamping, aggressive fluid resuscitation, and inotropic support can fail to reverse hypotension

• Cardiac Complications – MI – mortality of 19-66%

– Arrhythmias – mortality 46%

– Cardiac arrest – mortality 81-100%

– CHF – mortality of 41%

– Common as patients usually have simultaneous cardiac dz

ComplicationsSystemic

• Liver Failure – Due to hypoxic injury

• Although the liver is robust; can deal with a large degree of hypoxic injury it still must reabsorb hematoma and the increase in metabolism that is required to do this

– Patients usually develop jaundice on day 7

• Multisystem Organ Failure – Incidence of 64%

– Most common cause of death after 48 hrs

– Also referred to as a systemic inflammatory syndrome

ComplicationsSystemic

• Multisystem Organ Failure – “Two hit” hypothesis

• 1) Hemorrhagic shock – first ischemic insult primes the inflammatory response

• 2) Aortic Clamping – second ischemic insult • 3) Resuscitation – first reperfusion insult• 4) Aortic unClamping – second reperfusion insult

– Animal models support• PMNs primed by pre-op hemorrhage, and after operative

repair there was further activation with elevations of oxidative burst.

– These patients are walking into the hospital with oxidative injury

Mortality

• Between 43% to 70% depending on the study• Predictors

– Scoring systems • POSSUM – 12 physiologic variables and 6 operative variables

for calculated risk• Hardman index – Based on age, creatinine, hemoglobin, EKG

evidence of ischemia, h/o loss of consciousness • Multiple Organ dysfunction score (based on respiratory, renal,

hepatic, hematologic, neurologic, and cardiac)– Deaths bimodal

» Those that died 48 after repair had sig increases in MODS» Renal failure followed by hepatic failure at Day 10 are at

highest risk for mortality

Table 102-2. Logistic Regression Model Showing the Interaction of Significant Preoperative and Intraoperative Variables That Predicted Early Survival After

Ruptured Abdominal Aortic Aneurysm Repair

CREATININE (mg/dL) CLAMP SITE URINE OUTPUT (mL) PROBABILITY OF SURVIVAL (%)

≤1.3 Infrarenal ≥200 9090

≤1.3 Infrarenal 1-199 76

>1.3 Infrarenal ≥200 71

≤1.3 Suprarenal ≥200 65

≤1.3 Infrarenal 0 52

>1.3 Infrarenal 1-199 46

≤1.3 Suprarenal 1-199 39

>1.3 Suprarenal ≥200 33

>1.3 Infrarenal 0 23

≤1.3 Suprarenal 0 18

>1.3 Suprarenal 1-199 15

>1.3 Suprarenal 0 6

Logistic Regression Model Showing the Interaction of Significant Postoperative Complications That Predicted Early Survival After Ruptured Abdominal Aortic Aneurysm

MYOCARDIAL INFARCTION RESPIRATORY FAILURE COAGULOPATHY RENAL DYSFUNCTION PROBABILITY OF SURVIVAL (%)

No No No No 96

No No Yes No 91

No Yes No No 74

Yes No No No 66

No No No ↑Cr 66

No Yes Yes No 58

Yes No Yes No 49

No No Yes ↑Cr 48

Yes Yes No No 21

No Yes No ↑Cr 20

Yes No No ↑Cr 15

No No No Dialysis 15

Yes Yes Yes No 11

No Yes Yes ↑Cr 11

Yes No Yes ↑Cr 8

No No Yes Dialysis 8

Yes Yes No ↑Cr 2

No Yes No Dialysis 2

Yes No No Dialysis 2

Yes Yes Yes ↑Cr 1

No Yes Yes Dialysis 1

Yes No Yes Dialysis 1

Yes Yes No Dialysis 0

Yes Yes Yes Dialysis 0

Conclusions

• Diagnosis – Have RAAA on the differential, don’t miss the diagnosis

• Resuscitation – Less is more until aorta is clamped

• Surgery – Quick, safe exposure. Use a method that you are experienced with.

• Complications – Expect them

I would like to end with one more aorta…

mine