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AAA and Acute Limb Ischaemia Shoheb Hassan, Fourth Year Student, Aston Medical SchoolThanks to our partners!AAA – anatomy learning objectives ● Describe the four sections of the aorta ● Describe the major branches of the aortic arch ● Describe the layers of the aorta ● Describe the course of the abdominal aorta ● Describe the branches of the abdominal aorta ● Describe the structures that must be dissected in procedures to repair the aortaAAA – clinical learning objectives. ● What is an abdominal aortic aneurysm ● What are possible risk factors ● What are the clinical features ● Describe the screening programme in the UK ● What other differentials should you consider (renal colic, IBD, IBS, GI bleed etc) ● What are the relevant investigations (USS, CT) ● Describe the relevant management, including the surgical options (open repair vs endovascular) ● What are the main complications ● Describe the identification and management of a ruptured AAAAnatomy Four sections: 1. Ascending aorta. 2. Aortic arch. 3. Descending thoracic. • Through diaphragm at T12, to become… 4. *Descending abdominal aorta Wikipedia, Creative Commons.Branches of the aortic arch… • Brachiocephalic • Right subclavian. • Right arm. • Gives rise to right inferior thyroid artery • Right common carotid. • Head and neck. • Left common carotid. • Head and neck. • Left subclavian • Left arm. • Also gives rise to left inferior thyroid artery. Wikipedia, Creative Commons.TeachMeAnatomyCrossing the diaphragm • Aorta crosses diaphragm at T12 • Now enters abdominal cavity to become the abdominal aorta. • COA; 8,10,12. TeachMeAnatomyNow the abdomen… • Multitude of branches to supply the viscera, including: • Suprarenal arteries • Renal • L1-L2 • Coeliac – foregut-derived organs. • Superior mesenteric –Inferior mesenteric • Gonadal artery • Iliac vessels. GeekyMedicsIt’s tricky to remember but this is the best we got… https://youtu.be/ yVC4YWo_b_I?fea ture=sharedWhat structures do we dissect when repairing the aorta? Which ones did you get? • Skin and subcutaneous tissue. • Muscles and surrounding fascia • Rib cage (e.g. if thoracic aortic surgery). • Pericardium – ascending aorta or aortic arch repairs. • Mediastinal structures – thymus, lymph nodes, fatty tissue. • Pleura – thoracic aortic surgery. • Aortic wall itself – next slide is coming… • Branches of the aorta – as discussed early. • Vascular structures – e.g. iliac or femoral arteries for graft or anastamoic. placement. Case study: Demographic: 75 age, male PC: severe, constant abdominal pain, 2 hours ago, described as ‘ripping’ or ‘tearing’ in abdomen, radiating to lower back. Lightheaded, nauseas. History of PC: started suddenly 2 hours ago, no history of recent trauma or similar episodes in the past. PMH: hypertension (stage 2), hyperlipidaemia. Medication: amlodipine, atorvastatin (80mg). Social: 30 pack year history of smoking, >14 units of alcohol a week.Physical Examination: Vital Signs: Blood pressure 100/70 mmHg, heart rate 100 bpm, respiratory rate 20 bpm, temperature 37°C. General: Appears pale, diaphoretic, and in distress. Abdominal Examination: Slight tenderness to palpation in the epigastric and periumbilical regions, pulsatile mass palpable in the midline, extending to the right lower quadrant. No rebound tenderness or guarding noted. Peripheral Pulses: Diminished femoral pulses bilaterally. Neurological Examination: Alert and oriented, no focal deficits.Review of Systems: Cardiac: Denies chest pain or palpitations, no murmurs, thrills, etc. Respiratory: No cough or shortness of breath, no lung field sounds on auscultation, etc. Gastrointestinal: Severe abdominal pain, nausea, denies vomiting or diarrhoea. Neurological: Light-headedness, denies weakness or changes in sensation. Genitourinary: No loin tenderness, no changes in urinary frequency or color.What differentials shall we consider?What differentials shall we consider? • Urogenital - renal colic. • Mesenteric ischaemia – e.g. embolus, thrombus, mesenteric artery stenosis. • GI – peptic ulcer disease, gastritis, pancreatitis, intestinal obstruction, IBS, IBD, diverticulitis, appendicitis. • MSK pain – muscles, bones, joint pathologies. • Lumbar radiculopathy – referred pains.What is it? • Dilation of the abdominal aorta • >3cm • Can rupture -> LIFE-THREATENING. • Most commonly infrarenal A.D.A.M Quantum Medical Imaging, 2020.Pathophysiology Risk factors Aortic wall remodelling, e.g. from tunica media • Age – increasing elastin degradation, • Men from: • Genetic factors – Ehlers-Danlos, Marfan • Inflammation. syndrome. • Oxidative stress. • Caucasian • Smoking • Proteolysis. • Hypertension • CVS disease • Trauma – to abdomen • Obesity.Signs and symptoms Unruptured: • Most patients are asymptomatic • Can present as non-specific abdominal pain, or expansile mass. Rupture: • Clammy skin • Severe abdominal or back pain • Pulsating abdominal mass • Nausea and vomiting • Hypotension. • Loss of consciousness. • Tachycardia. • Abdominal tenderness • Decreased urine output – consider • Syncope. why? • Shortness of breath – consider why?What are the key investigations to diagnose an AAA?Investigations for unruptured AAAs. US – initial – images of next slides. CT angiogram – after US confirmation, more anatomical detail, helps guide elective surgery to repair the aneurysm. • Note intramural thrombus. Gomes et al, 2018 LITFL, Hartung and Cadogan, 2023. Screening • PREVENTION IS BETTER THAN CURE. • All men offered US at 65 Y/O. • Why aren’t women routinely screened? PHE, 2020Interson Corporation, 2019Interpreting our diameters… Length (cm) Classification Management <3 Normal Nothing. 3-4.4 Small Scan in 12 months 4.5-5.4 Medium Scan in 3 months >5.5 Large Vascular surgery referral within 2 weeks.Management for uncomplicated AAA • Lifestyle: • Smoking • Weight loss, diet, exercise. • Management of CVS disease, including BP , diabetes, hyperlipidaemia. • Statins. • Elective repair: • For those >5.5cm, or expanding 1cm/year, or symptomatic patient. • Open repair via a laparotomy • Endovascular aneurysm repair (EVAR) using a stent inserted via the femoral arteries 1. INCISION INTO ABDOMEN. 2. CLAMP AORTA. 3. INCISE AORTA LONGITUDINALLY TO EXPOSE LUMEN. 4. REMOVE ANEURYSMAL SEGMENT 5. GRAFT PLACEMENT. 6. CLAMPS REMOVED 7. INCISION CLOSED. Wikimedia Commons1. ACCESS THE ARTERY – USUALLY VIA GROIN FOR THE FEMORAL ARTERY. 2. INSERTION OF A CATHETER, AND THEN A GUIDEWIRE. 3. INSERTION OF STENT ALONG THE GUIDEWIRE. 4. SECURE THE ENDOVASCULAR STENT. 5. CATHETER AND GUIDEWIRE REMOVED. 6. INCISION CLOSED Wiki, Creative CommonsManaging a ruptured AAA • Big, big problem… EMERGENCY. • Classic triad in 50% – back pain, hypotension, pulsatile mass. • ABCDE management initially – high flow O2, IV access via two large bores, urgent bloods, group and save, crossmatching. • If shock, raise BP cautiously – why? • Permissive hypotension. • Transfer to vascular centre. • If patient unstable -> immediate open surgical repair. • If stable –> stable angiogram for CT angiogram.Complications of surgical management: • General risks – bleeding, infection, VTEs. • Open surgery general risks: wound complications (e.g. infection, dehiscence), vessel damage, pseudoaneurysm. • Endovascular repair – endoleak, infection.inking of the stent graft, endograft • Delayed complications: e.g. aneurysm recurrence • Other organs: renal hypoperfusion during surgery (e.g. due to clamping). Cheng, 2018.Peripheral Arterial Disease P AD – anatomical learning objectives: • Recognise the pulse points in the lower limb • lata, iliotibial tract, femoral sheath and its contents, obturator nerve, sciatic nerve, femoral nerve, common peroneal nerve, tibial nerve, popliteal fossa and key vessels within and identify the main muscles and muscle groups that the nerves supply. • Identify and side the femur, tibia and fibula • Recognise that the femoral artery is a branch of the external iliac which is a branch of the abdominal aorta • Recognise the femoral artery as the main artery of the lower limb • Describe the femoral triangle • Recognise the other vessels in the thigh that supply the lower limb and describe their course • Describe the course of the popliteal artery in the leg • Describe the arterial supply of the footAbdominal aorta bifurcates into two common iliac arteries – left and right. The common iliac each bifurcate – external and internal iliac. Wikimedia Commons External iliac continues to form the femoral artery. Note where is intersects with the inguinal ligament – MIP . Marx J. Rosen’s emergency practice. 6th ed. St Louis: Mosby; OSCEstop 2006. Femoral artery turns around the femur, to descending posterior into the popliteal fossa. TeachMeAnatomy Cleveland Clinic, 2021Popliteal artery (pulse may be felt in popliteal fossa – flex the knee): ➔Anterior tibial artery ➔Dorsalis pedis artery (pulse false over dorsum of foot) ➔Posterior tibial arteries • Pulse felt posterior medial malleolus. ➔ Fibular (peroneal artery). TeachMeAnatomyLower limb pulses 1. Femoral. 2. Popliteal. 3. Posterior tibial 4. Dorsalis pedis Femoral triangle • Superomedial aspect of anterior thigh. • Home to very important structures: • Vascular – femoral artery, femoral vein. • Lymphatics. NAVAL – lateral to medial: • Femoral nerve. 1. NERVE. • Inguinal lymph nodes. 2. ARTERY. 3. VEIN. 5. LYMPH NODES. TeachMeAnatomy Clinical significance • Femoral pulse – where it crosses inguinal ligament. • Femoral artery access – e.g. for coronary angiography. • Femoral nerve block. • Lymph node biopsy. • Other pathologies: femoral, hernia, saphena varix, venous thrombosis, nerve entrapment, tumours.Finally, the fascia lata forms the roof…Summary of femoral triangle borders…. Border Structure Medial Adductor longus Lateral Sartorius Superior Inguinal ligament – runs from ASIS to pubic tubercle Roof Fascia lata Floor Pectineus, iliopsoas, and adductor longus musclesBONUS ANATOMY: THIGH COMPARTMENTS Compartment Main nerve Anterior Femoral Medial Obturator Posterior Sciatic Compartment Nerve Function Anterior Deep peroneal Dorsiflexion of foot. Toe extension Lateral Superficial Foot eversion, peroneal plantar flexion. Superficial Tibial Plantar flexion posterior Deep posterior Tibial Plantar flexion,toe flexion, foot inversion, Miciak and Jurkiewicz, 2023NEUROVASCULAR STRUCTURES – LATERAL TO MEDIAL: • POPLITEAL: NERVE, VEIN, ARTERY. • ‘NEVA (NEVER) POP YOUR KNEE.’ • FEMORAL TRIANGLE: NERVE, ARTERY, VEIN. • ‘NAVY PANTS.’P AD – clinical learning objectives: • What is acute limb ischaemia • Describe the aetiology behind acute limb ischaemia • Describe the clinical presentation of acute limb ischaemia • What other differentials should you consider (eg DVT, nerve compression) • What investigations are appropriate (bloods, ECG, doppler, CT angio) • What’s the appropriate management- conservative vs surgical (embolectomy, bypass, angioplasty, amputation, palliation) • What’s the appropriate long term management • What are possible complications (mortality, compartment syndrome)Case study #2 Demographic: 65 year old male, Michael Smith. PMH: hypertension, hyperlipidaemia, previous CABG. PC: sudden onset 8-9/10 pain and pallor in right lower leg. History of PC: woke up this morning with severe pain, constant and severe. Right foot feels cold, numb, and unable to move toes. No recent tumour, no prolonged immobilisation, no previous similar episodes. Systems: no chest pain, no SOB, no palpitations. Medications: atorvastatin, aspirin.Examination: Vitals: BP 150/95, HR 110, RR 17. Temperature: apyrexic, 37°C General inspection: distressed, anxious. Cardiac: regular heart rate, rhythm, no murmur. Pulmonary: normal. Abdominal: soft, non-tender. Neuro: 2/5 right lower extremity, reduced sensation to light touch and pinprick. Vascular: absent dorsalis pedis and posterior tibial pulses in right foot. Right lower limb pale, cool to touch, with CFT >3s. Most likely diagnosis? What differentials to consider? Think: sudden onset, unilateral, lower limb pain.•*PAD – acute limb ischaemia •Arterial thrombosis. •Deep vein thrombosis. •Peripheral nerve compression, spinal cord compression. •Sciatica, peripheral neuropathy, radiculopathy. •Compartment syndrome Acute limb ischaemia • Sudden reduction in limb perfusion • Limb viability if compromised. • Symptoms – 6 P’s. • Paralysis • Pulseless • ‘Perishingly’ cold • Pallor • Paraesthesia. • Pain at rest. One of three main patterns of PAD: 1. Intermittent claudication. Wikimedia Commons 2. Critical limb ischaemia/CLTI 3. Acute limb-threatening ischaemia.Risk factors and Aetiology Risk factors: Aetiology: • Prior PAD. • Embolism • Smoking. • Thrombosis in situ. • DM. • Trauma • Hypertension. • Compartment • Hyperlipidaemia. syndrome. • Age • Obesity. • Hypercoagulable states • Trauma Diagnosis • Examination – e.g. peripheral vascular. • Investigations: • US arterial doppler • ABPI • Angiography (CT or MRI) prior to interventions (next slide) Value Interpretation 0.9-1.3 Normal 0.6-0.9 Mild Wikimedia Commons 0.3-0.6 Moderate <0.3 Severe Summary of management before exploring further… SURGICAL EMERGENCY Long-term management: ABCDE: • High flow O2, IV access (IV heparin ASAP) • Lifestyle – smoking cessation, weight • Vascular review needed Conservative: loss, regular exercise. • Pain relief - IV opioids. • Anti-platelet agents, e.g. low-dose aspirin or clopidogrel. • For Rutherford 1 and 2a (less severe forms) prolonged course of heparin. • Anti-coagulation – warfarin or DOACs. • Surgery if not improvement seen. Definitive management - surgery • Management comorbidities and • Endovascular thrombolysis, or thrombectomy. predisposing conditions – e.g. AF, • Endarterectomy hypertension, diabetes, obesity. • Surgical thrombectomy. • Prescribe a statin – atorvastatin 80mg. • Bypass surgery. • Angioplasty • Support with mobility and rehab – physiotherapy, occupational therapy, • other interventionsreversible ischaemia, or if not suitable for MDT involvement. Intraarterial thrombolysis. Johnson Francis, 2015 Balloon angioplasty. Endarterectomy. Wikimedia Commons Wikimedia CommonsTHANK YOU!@supta_uk @SUPTAUK www.supta.uk