16- Renal and visceral occlusive and aneurysmal diseases - artificial arteriovenous fistulas, haemodialysis access.

what is renal artery stenosis

• complete blockage of blood flow through one or both of the main renal a. or its branches

how does the stenosis affect the kidneys

• affected kidney recceives less blood → atrophy

• one kidney affected → other one will take over

• both kidneys affected → acute renal failure

what is the cause of RAS

• thromboemboli

• atherosclerosis

• fibromuscular dysplasia

what are the symptoms of RAS

• HT, headache, blurry vision

• aching flank pain, abdominal pain, fever, vomiting, haematuria

how do you diagnose RAS

• abdominal bruit over the renal arteries

• lab test- creatinine, urine analysis

• imaging- CT, US< MRI

what is the treatment of RAS

• manage HT

• surgery

  • balloon angioplasty +/- stent

  • removal of atrophied kidney

what are the symptoms of renal aneurysms

• very rare, mainly asymptomatic

• flank pain, HT, reduced kidney function

what is the treatment of renal aneurysms

• for small with no risk of rupture→ monitor

• medication, surgery

what is visceral occlusive disease

• narrowing of arteries that supply blood to intestines, spleen and liver

• cause by atherosclerosis → reduced blood flow to these organs → intestinal ischemia

what are the causes of acute mesenteric ischemia

• due to embolisation

• acute abdominal syndrome

• acute intestinal necrosis

what are the causes of chronic mesenteric ischemia

• due to atherosclerosis

  • or FMD

• postprandial pain

• weight loss

describe acute mesenteric ischemia

• critical blockage of intestinal blood flow → small intestine necrosis → abdominal pain

• ischemia → gangrene of wall

what are the symptoms of visceral occlusive disease

• abdominal pain

• metabolic acidosis

• nausea

what can visceral occlusive disease cause

• acute/ chronic mesenteric ischemia

what is the treatment of acute mesenteric ischemia

• stents

• thrombolysis

• open surgery to remove/ bypass

• broad spectrum antibiotics to prevent sepsis

• anticoagulants + painkillers

what is chronic mesenteric ischemia

• intestinal angina

• atherosclerosis of celiac, SIMA, IMA → intestinal hypoperfusion → postprandial epigastric pain → food aversion + weight loss

what is the treatment of chronic mesenteric ischemia

• open surgery

• endovascular treatment

• broad spectrum antibiotics to prevent sepsis

• anticoagulants + painkillers

what is visceral artery aneurysm

• aneurysm in celiac and mesenteric arteries

  • splenic, renal, hepatic, mesenteric

describe splenic artery aneurysms

• most common

• diameter ~1cm

• usually asymptomatic or LUQ pain that radiates to shoulder

• rupture → haemodynamic instability

• diagnosis → CTA

• surgery if rupture occurs

how do you diagnose visceral artery aneurysms

• US

• CT angio

what is the treatment of visceral artery aneurysms

• risk of rupture is high if >2cm or rapidly growing

• small should be monitored + meds for BR

• elective surgical repair is only definitive cure

  • graft

what is artificial arteriovenous fistulas

• surgical connection made between artery and vein for haemodyalisis treatments

• creates high flow rate, low incidence of thrombosis

what is haemodyalisis

• uses diffusion to remove solutes and water from blood when kidneys dont work

where is artificial arteriovenous fistulas located

• in arm

• anastomosis creates access to arterial blood

• pumped out of body and back into venous system

what is haemodialysis acess

• access allows blood to travel through soft tubes to dialysis machine to dialyser

what are the types of haemodialysis access

• AV fistula

• AV graft

• central venous catheter

what is AV graft

• access made using soft tube to join artery and vein in arm

• mature faster than fistula

• high risk of narrowing → thrombosis

what is central venous catheter

• soft tube in large vein- usually in neck

• blood flow is less than other