Perioperative management - Endoaneurysmorrhaphy with intraluminal straight graft placement in infrarenal abominal aortic aneurysm - Vascular Surgery - vascular surgery
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Indications
The indication for open repair of abdominal aortic aneurysm (AAA) basically results from comparing the patient's individual risk of rupture in the spontaneous course of the disease with the risk of open surgery. If the risk of spontaeous rupture over the course exceeds the individual surgical risk, open surgery is usually indicated.
Rupture risk classification
Factors Low risk Moderate risk High risk Aneurysm diameter <5 cm 5–6 cm >6 cm Growth rate per year <0,3 cm 0,3–0,5 cm >0,5 cm Smoking/COPD Low Moderate High Family history None Isolated Common Arterial hypertension None Well controlled Unstable despite treatment Morphology Fusiform Saccular Evaginations Gender Male Female Indication for surgery
Classification Size Wall Presentation Indication for surgery Asymptomatic infrarenal >5 cm ♂
>4.5 cm ♀
Intact None Elective Asymptomatic supraaortic >6 cm Intact None Elective Symptomatic Independently of other factors Intact Spontaneous pain; tenderness in abdomen, back or side Urgent, within 24 hours Ruptured Independently of other factors Contained or free rupture Diffuse severe spontaneous pain / tenderness of tense abdomen, with/without hemorrhagic shock Emergency Aortoduodenal fistula Intermitted vomiting, melena Emergency Aortocaval fistula Right heart failure, fistula bruit, truncal cyanosis, concurrent contrast enhancement of aorta & inferior vena cava Emergency There are two types of repair in AAA:
- open replacement of the abdominal aorta with a straight (tubular) or bifurcation graft (OAR, open aortic repair)
- endovascular placement of a stent graft (EVAR, endovascular aortic repair)
Laparoscopic aneurysm repair surgery, usually performed in combination with mini-laparotomy, is of lesser importance.
The following recommendations serve as a guide to choosing between OAR and EVAR:
OAR (trans-/retroperitoneal)
- Normal life expectancy
- Low surgical risk (fitness)
- Anatomy unsuitable for EVAR: landing zone; aneurysm neck (angle, length); iliac vessels (stenosis, elongation, kinking); thrombi; calcification
- Marfan and other connective tissue disorders
EVAR (standard /customized graft)
- Prior abdominal surgery
- Limited life expectancy
- High surgical risk
- Anatomy suitable for EVAR (see above)
Since stent graft systems are often of large caliber, EVAR requires adequate iliac artery lumen for access. Iliac arteries with atherosclerotic stenosis, tortuosity, kinking, or aneurysmal dilation are a problem.
In the long run, endovascular aortic grafts are associated with a higher complication rate than open aortic surgery.
The BAR Score Calculator -> www.britishaneurysmrepairscore.com can quickly calculate patient mortality risk for EVAR or OAR, which can be useful when advising patients about the risk of elective EVAR or OAR.
Video example:
Asymptomatic infrarenal AAA greater than 5 cm in diameter do not lend themselves to EVAR due to aneurysmal neck angulation greater than 60°.
Contraindications
Contraindications for open aneurysm repair:
• Serious cardiopulmonary risks (e.g. NYHA IV, COPD Gold stage IV)
• Acute or chronic inflammatory abdominal conditions (e.g., florid ulcerative colitis, recurrent sigmoid diverticulitis)
• History of multiple extensive abdominal procedures ("hostile abdomen")
• Cirrhosis of the liver
• Advanced tumor disease
• Compensated renal failure (relative contraindication)Preoperative diagnostic work-up
Medical history
- Cardiac history
- Medication history
- Risk factors: nicotine abuse; arterial hypertension; coronary heart disease; cardiac failure; diabetes; manifest renal failure with/without dialysis; coagulopathy
- Walking distance/claudication
- Back or side pain?
- Mesogastric and upper quadrant complaints?
Inspection
- Skin changes
- Muscular abnormalities
- Orthopedic malalignment
- Skin color
- Body hair
- Trophic changes
- Swelling; edema; mycosis; phlegmon; leg ulcers
Palpation
- Bilateral comparison of pulse status
- Bilateral comparison of skin temperature
- Possibly expansive pulsating mesogastric tumor
- Pasty painful abdomen with large pulsating mass: Suspected contained rupture
Auscultatory bilateral comparison of the limb arteries
Ankle-Brachial Index (ABI)
- ABI = systolic BP of posterior tibial artery / systolic BP of brachial artery
ABI value PAD severity > 1,3 Falsely high values (suspected Mönckeberg medial sclerosis, e.g. in diabetes) > 0,9 Normal finding 0,75 - 0,9 Mild PAD 0,5 - 0,75) Moderate PAD < 0.5 schwere PAVK - ABI < 0.9 is considered evidence of significant PAD.
- Determining the ankle-brachial index (ABI) through non-invasive Doppler occlusion pressure measurement is a suitable test for confirming PAD.
- PAD diagnosis is determined by the ABI value with the lowest ankle artery pressure.
- A pathologic ankle-brachial index is an independent risk indicator for increased cardiovascular morbidity and mortality.
Color-flow Doppler ultrasonography
- Carotid arteries, abdominal aorta, limb arteries
- Stenoses and occlusions in almost all vascular regions apart from chest
- Allows quantifying the degree of stenosis and assessing plaque morphology
- Sensitivity and specificity around 90%
- Well suited as screening modality
Contrast-enhanced spiral computed tomography angiography (SCTA)
- Broad range of indications: traumatic vascular lesion (esp. trunk); vascular dissection/rupture; aneurysm; arterial thrombosis/embolism; portal vein/mesenteric vein thrombosis; pulmonary artery embolism; PAD; vascular tumors
- Benefits: rapid; detects relevant comorbidities; visualizes peripheral arteries; sensitivity and specificity each about 90%
- Drawbacks: Radiation and contrast agent exposure, allergies (about 3%), no functional assessment
- Aneurysm: three-dimensional imaging of the entire aorta and its morphology, sufficiently accurate dimensions for EVAR, visualizing luminal condition with thrombosis and calcification
Angiography (intra-arterial DSA)
- Visualization of aortic branches (stenoses; renal polar arteries; visceral iliac and femoral arteries)
- Dynamic visualization
- Drawbacks: limited visualization of aneurysm morphology (only patent lumen); ionizing radiation; nephrotoxic contrast agent; invasive
Cardiac check
- Resting ECG
- Exercise ECG
- Echocardiography
Chest x-ray
Possibly spirometry
Laboratory panels
- Blood count
- Electrolytes
- Coagulation
- Kidney function parameters
- Liver function parameters
- Blood lipids
- Blood group
Special preparation
- Enema the evening before
- Hair cut in surgical field
- Order packed RBCs
- Foley catheter
- Administer prophylactic perioperative antibiotics 30 min. before beginning surgery (see KRINKO recommendation, Robert Koch Institute)
Informed consent
General surgical risks
- Allergy/intolerance (e.g., latex, medication)
- Wound infection, sepsis
- Thromboembolism
- Skin/tissue/nerve damage due to positioning on OR table or procedure-related measures
- Keloid
Specific procedural risks
- Bleeding, blood transfusions, transmission of hepatitis/HIV through allogeneic blood transusion
- Secondary bleeding, possibly requiring revision surgery
- Thrombosis of the graft and possibly adjacent vascular segments; hypoperfusion of the legs; gangrene; limb loss/amputation; revision surgery
- Injury of adjacent organs (e.g. ureter; urinary bladder; bowel; kidneys; etc.), repeat surgery
- Kidney failure secondary to preexisting renal insufficiency or additional renal artery interventions, possibly ESRD
- Nerve injury with dysesthesia or pain; weakness of abdominal muscles; weakness or partial paralysis of thigh muscles; each of which may be temporary or permanent
- In men: sexual dysfunction, infertility in case of vas deferens injury, and non-functional contralateral vas deferens
- Impaired perfusion of the bowel/ischemic colitis, possibly resection, temporary or permanent stoma
- Spinal ischemia/paraplegia
- Abdominal compartment syndrome: Multi-organ failure, intensive care medicine, relaparotomy
- Lymphedema, temporary or permanent
- Infection-induced graft suture breakage: bleeding, sepsis, relaparotomy
- Side effects of iodine-containing contrast media
- Suture aneurysm, surgical revision, possibly endovascular
- Incisional hernia
- Intra-abdominal adhesions
Anesthesia
Positioning
Operating room setup
Special instruments and fixation systems
Postoperative management
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