ABS Vascular Surgery cheat sheet

Infrarenal abdominal aortic aneurysm is defined as an aortic diameter of 3.0 cm or greater; the normal infrarenal aorta measures roughly 1.5-2.0 cm.

Elective repair thresholds are 5.5 cm in men and 5.0 cm in women, or growth exceeding 0.5-1.0 cm per year, or symptoms, or a saccular morphology.

Surveillance intervals: 3.0-3.9 cm every 3 years; 4.0-4.9 cm every 12 months; 5.0-5.4 cm every 6 months.

Annual rupture risk is about 1% at 5.5-6.0 cm, rises steeply above 6.5 cm, and exceeds 10-20% per year above 7 cm.

EVAR has lower 30-day mortality than open repair (about 1% versus 3-5%) but higher reintervention and late rupture rates; survival curves converge by 2-4 years.

Popliteal artery aneurysm is repaired at 2.0 cm or greater or when mural thrombus embolizes; 50% are bilateral and 40% coexist with an abdominal aortic aneurysm.

Isolated iliac artery aneurysm is repaired at 3.0-3.5 cm; bilateral internal iliac occlusion risks buttock necrosis, colonic ischemia, and spinal cord ischemia.

Mycotic (infected) aneurysm is most often caused by Salmonella species; treatment is excision with debridement plus extra-anatomic bypass or covered in-situ graft and prolonged antibiotics.

Thoracic repair thresholds are about 5.5 cm for the ascending aorta (4.5-5.0 cm in Marfan or bicuspid valve) and 6.0-6.5 cm for the descending aorta.

TASC II classification: category A and B lesions are treated endovascularly; category C and D lesions favor open bypass.

Leriche syndrome triad: buttock and thigh claudication, absent or diminished femoral pulses, and erectile dysfunction from distal aortic or bilateral common iliac occlusion.

Aortobifemoral bypass has 5-year primary patency of about 85-90% with 1-3% elective mortality.

Focal iliac stenoses stented percutaneously achieve 5-year patency of roughly 80-90%; covered stents are used for complex or hemorrhagic lesions.

A resting ankle-brachial index of 0.90 or less is abnormal; claudication typically corresponds to 0.5-0.9, and chronic limb-threatening ischemia to less than 0.4.

Fibromuscular dysplasia causes a string-of-beads appearance in young women and is treated with balloon angioplasty without a stent.

Atherosclerotic renal artery stenosis is managed medically first; stenting is reserved for flash pulmonary edema or refractory hypertension with critical stenosis.

Chronic mesenteric ischemia usually requires stenosis of at least two of the three splanchnic vessels; revascularization prioritizes the superior mesenteric artery.

Symptomatic internal carotid stenosis of 70-99% by NASCET criteria benefits from endarterectomy, with an absolute risk reduction near 15% over 2 years; 50-69% has modest benefit; less than 50% has none.

Endarterectomy should be performed within 14 days of the index event, ideally 3-7 days, in the neurologically stable patient.

Duplex criteria for 70% or greater stenosis: peak systolic velocity above 230 cm/s, internal-to-common carotid velocity ratio above 4.0, and end-diastolic velocity above 100 cm/s.

Perioperative stroke and death rates should be below 3% for asymptomatic and below 6% for symptomatic patients.

Cranial nerve injury occurs in roughly 5-7% of endarterectomies; the hypoglossal, vagus/recurrent laryngeal, marginal mandibular, and glossopharyngeal nerves are at risk.

Carotid stenting carries more minor stroke and fewer myocardial infarctions and cranial nerve injuries than endarterectomy; endarterectomy is favored above age 70, stenting for hostile neck or severe cardiac disease.

Hyperperfusion syndrome occurs in 1-3% of endarterectomies, typically days 1-7, with headache, seizure, or intracerebral hemorrhage, and is linked to postoperative blood pressure elevation.

Carotid body tumor splays the internal and external carotid arteries; Shamblin classification predicts resection difficulty and cranial nerve risk.

Asymptomatic stenosis of 60% or greater is managed with statin and antiplatelet therapy, with endarterectomy selected for younger patients with long life expectancy.

Rutherford categories 1-3 describe claudication and categories 4-6 describe chronic limb-threatening ischemia (rest pain, tissue loss).

An ankle-brachial index of 1.3 or greater indicates non-compressible calcified vessels; a toe-brachial index below 0.7 or pulse volume recordings are then used.

Claudication therapy rests on supervised exercise (greatest walking improvement), cilostazol, statin, antiplatelet, and smoking cessation.

Superficial femoral artery disease is treated endovascularly when lesions are short and by vein bypass when long or complex.

BEST-CLI showed that in patients with a usable single-segment great saphenous vein, bypass produced better amputation-free survival than endovascular therapy for chronic limb-threatening ischemia.

Acute limb ischemia uses Rutherford classes I-III; class III is irreversible, and class IIb (rest pain with sensory and motor deficit) requires immediate revascularization.

The six Ps of acute ischemia: pain, pallor, paresthesia, paralysis, pulselessness, and poikilothermia.

Compartment pressures above 30 mmHg or a diastolic-to-compartment delta below 30 mmHg after revascularization indicate four-compartment fasciotomy.

Popliteal entrapment syndrome, cystic adventitial disease, and Buerger disease are non-atherosclerotic causes in younger patients.

CEAP classification runs C0 to C6, where C6 is an active venous ulcer.

Venous ulcers are shallow, in the gaiter area, with hyperpigmentation and lipodermatosclerosis; compression of 30-40 mmHg is applied once the ankle-brachial index exceeds 0.8.

Duplex reflux thresholds are greater than 0.5 seconds in superficial veins and greater than 1.0 second in deep veins.

Proximal deep vein thrombosis (popliteal or above) is anticoagulated; isolated distal thrombosis may be monitored with serial duplex imaging.

May-Thurner syndrome is compression of the left common iliac vein by the right common iliac artery and is treated with thrombolysis plus stenting.

Phlegmasia cerulea dolens is massive iliofemoral thrombosis with threatened venous gangrene; treatment is anticoagulation with catheter-directed thrombolysis or thrombectomy.

IVC filters are placed for absolute contraindication to anticoagulation or recurrent pulmonary embolism despite therapy, and are retrieved when possible.

Superficial thrombophlebitis extending 5 cm or more from the saphenofemoral junction is treated with fondaparinux 2.5 mg daily for 45 days.

Lymphedema shows a positive Stemmer sign and is non-pitting; treatment is complex decongestive therapy with compression and skin care.

Hard signs of vascular injury are pulsatile bleeding, expanding hematoma, thrill or bruit, absent distal pulses, and evident ischemia; these mandate immediate exploration or angiography.

Soft signs, including a small hematoma or nerve deficit, require an ankle-brachial index; a value below 0.9 prompts CT angiography.

Knee dislocation carries a high risk of popliteal artery injury; ankle-brachial index is measured in all dislocations and repair is combined with fasciotomy.

Damage control uses temporary shunting (8-10 Fr) for prolonged ischemia time, with ligation reserved for the exsanguinating patient.

Takayasu arteritis affects women under 40 with aortic and subclavian stenoses, blood pressure discrepancy, and absent pulses; steroids are given and revascularization is delayed until remission.

Giant cell arteritis affects patients over 50 with headache, jaw claudication, and visual loss with an elevated sedimentation rate; steroids are started immediately and temporal artery biopsy confirms.

Buerger disease affects young male smokers with distal small-vessel occlusion and corkscrew collaterals; only smoking cessation halts progression.

Polyarteritis nodosa produces microaneurysms of medium vessels; Behçet disease can cause aortic and venous aneurysms requiring immunosuppression plus repair.

Radiation arteritis creates a hostile, fibrotic field; bypass is routed outside the radiated tissue and endovascular options are limited.

Ankle-brachial index divides the higher of the dorsalis pedis or posterior tibial pressure by the higher of the two brachial pressures; cuff width should exceed limb diameter by about 20%.

Segmental pressures and pulse volume recordings localize disease; a systolic drop greater than 20 mmHg between adjacent segments indicates stenosis.

Toe-brachial index below 0.7 is abnormal and is used when the ankle-brachial index exceeds 1.3.

Duplex diagnosis of deep vein thrombosis relies on loss of compressibility, absence of phasic flow, and failure to augment with distal squeeze.

Preoperative vein mapping identifies a great saphenous vein of 3 mm or more as suitable bypass conduit.

CT angiography has high sensitivity for trauma and operative planning but carries radiation and contrast nephropathy risk.

Gadolinium-enhanced MR angiography is avoided when eGFR is below 30 because of nephrogenic systemic fibrosis; time-of-flight sequences are an alternative.

Digital subtraction angiography remains the reference standard but is invasive, with a 0.5-2% complication rate, and is generally reserved for concurrent intervention.

Skin perfusion pressure below 30 mmHg predicts poor wound healing and guides amputation level when ankle pressures are unreliable.

Endoleak types: I, attachment site; II, branch or lumbar backflow; III, fabric or component defect; IV, graft porosity; V, endotension without visible flow.

Type I and type III endoleaks are treated when detected; type II is observed unless the sac enlarges by more than 5 mm.

Access-site complications of endovascular repair include pseudoaneurysm, arteriovenous fistula, retroperitoneal hematoma, dissection, and limb ischemia.

Intraoperative unfractionated heparin is dosed at about 100 units/kg with an activated clotting time target above 250 seconds, and higher for carotid interventions.

Protamine sulfate 1 mg reverses approximately 100 units of heparin and is dosed on total heparin administered.

Aortic graft infection, most often Staphylococcus epidermidis, is treated with graft excision, debridement, extra-anatomic revascularization, and prolonged antibiotics.

Reperfusion injury after revascularization can cause compartment syndrome, rhabdomyolysis, myoglobinuric renal failure, and hyperkalemic arrhythmia.

TEVAR is first-line for complicated type B aortic dissection; spinal cord ischemia complicates 3-5% and is managed with permissive hypertension and cerebrospinal fluid drainage.

Anastomotic pseudoaneurysm results from graft infection or technical failure and requires culture-directed revision.

The Revised Cardiac Risk Index scores ischemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, creatinine above 2 mg/dL, and high-risk surgery including open aortic repair.

Abdominal compartment syndrome is intra-abdominal pressure above 20 mmHg with new organ dysfunction and is treated with decompressive laparotomy and an open abdomen.

Spinal cord ischemia after thoracic aortic repair is managed with mean arterial pressure above 90-100 mmHg, cerebrospinal fluid drainage to below 10 mmHg, and hemoglobin above 10 g/dL.

Postoperative hypotension after aortic reconstruction warrants evaluation for bleeding, myocardial infarction, sepsis, and adrenal insufficiency.

Acute kidney injury after aortic or contrast procedures results from hypotension, atheroemboli, or contrast toxicity; creatinine peaks at 3-5 days.

Lung-protective ventilation at 6 mL/kg predicted body weight reduces ventilator-induced injury in acute respiratory distress syndrome.

Restrictive transfusion with a hemoglobin trigger of 7-8 g/dL is standard in the absence of active cardiac ischemia.

Perioperative glucose is maintained at 140-180 mg/dL, and enteral nutrition is started within 24-48 hours when feasible.

Aspirin 81-325 mg daily is lifelong after revascularization; dual antiplatelet therapy follows stenting for 1-6 months depending on stent type.

High-intensity statin therapy (atorvastatin 40-80 mg) started before surgery reduces perioperative mortality and late graft failure.

Smoking cessation for at least 4 weeks before elective surgery lowers pulmonary complications and improves graft patency.

Beta-blockers are not given routinely; when indicated they are started days to weeks before surgery and never stopped abruptly.

Glycemic target is HbA1c below 8% with perioperative glucose of 140-180 mg/dL.

Cilostazol is contraindicated in heart failure; pentoxifylline has minimal demonstrated benefit for claudication.

Below-knee amputation preserves the knee and reduces the energy cost of walking to roughly 10-40% above normal, versus 60-100% for above-knee amputation.

Diabetic plantar neuropathic ulcers require total contact casting or a removable walker for offloading; pressure relief matters more than dressing choice once infection is controlled and perfusion is adequate.

Wound care sequence: restore perfusion, debride nonviable tissue, control infection, offload pressure, and use moist wound healing or negative-pressure therapy for large cavitary wounds.