01Principles and purposeThe professional or clinical skill and the decisions it supports.
Vascular access creates the working route for angiography and endovascular treatment. A needle enters the vessel, a guidewire secures the path, and a sheath or catheter allows repeated device exchange while limiting trauma and blood loss. Access is a clinical decision rather than a routine preference. The common femoral artery offers a large, familiar, compressible route; the radial artery may reduce access bleeding and permit earlier sitting and walking but limits sheath size and can spasm or occlude; brachial and axillary routes may improve reach but make haemostasis and nerve protection more difficult. Diseased, calcified, previously operated or thrombosed vessels may make the usual route unsafe.
Embolisation is intentional endovascular occlusion. It is used for active bleeding, aneurysm or pseudoaneurysm exclusion, arteriovenous malformations, venous disease, tumour devascularisation and organ-specific treatments. The operator advances a catheter, often a microcatheter, as selectively as anatomy allows and delivers an agent under imaging. The effect is governed by agent properties, particle size, catheter position, injection rate, vessel resistance, collateral pathways and arteriovenous shunts. A technically easy proximal occlusion can fail if collateral inflow continues; overly distal or refluxed embolisation can infarct normal tissue.
Capability rests on maintaining control before, during and after the irreversible step. Pre-procedure imaging maps access vessels and target arterial supply. Ultrasound reduces blind puncture and identifies plaque or a high bifurcation. Angiography confirms catheter position and flow, but it is a dynamic sampling of anatomy: vasospasm, hypotension and intermittent bleeding can hide a culprit. Completion imaging must be interpreted with the therapeutic objective, and post-procedure surveillance looks for both access-site and target-territory complications.
Key points
- Choose access from the target, vessel calibre and disease, required sheath size, device length, ability to compress the artery and the consequences of occlusion; recent cross-sectional imaging and ultrasound should inform the choice.
- Real-time ultrasound shows lumen, plaque, bifurcation, vein and needle tip and is the recommended first approach for common femoral arterial puncture in the CIRSE arterial-access standard.
- The Seldinger sequence requires free blood return, gentle guidewire passage, wire position confirmation, tract dilation and sheath placement while continuously controlling the wire.
- Common femoral access accommodates large devices and is compressible, radial access enables earlier mobilisation but has calibre, spasm and occlusion constraints, and brachial or axillary access carries less forgiving bleeding and nerve risks.
- Embolisation deliberately reduces or stops flow; selectivity and agent choice depend on whether the aim is proximal mechanical occlusion, distal bed devascularisation, temporary control, permanent exclusion or flow preservation.
- Coils and plugs produce focal mechanical occlusion, particles travel with blood flow into a vascular bed, gelatin provides temporary occlusion, and liquid agents can penetrate complex channels but demand excellent control.
- Never deliver an embolic agent until angiography has defined target supply, dangerous collaterals, shunts and branches to organs such as spinal cord, brain or bowel.
- An angiographic endpoint must match the clinical aim: reduced tumour blush, exclusion of a pseudoaneurysm or cessation of extravasation while preserving essential non-target perfusion.
- After the procedure, confirm haemostasis, access-vessel patency, distal perfusion and target-organ status; delayed pseudoaneurysm, rebleeding, infection or post-embolisation symptoms may emerge after an initially satisfactory angiogram.
02Situations and prioritiesThe context, relevant information and actions that matter most.
The common femoral artery is assessed above its bifurcation and below the inguinal ligament over the femoral head, avoiding plaque and adjacent vein; ultrasound visualises the actual anatomy rather than relying on landmarks alone.
A wire should advance without force along the expected vessel course; resistance, buckling, pain or an unexpected fluoroscopic path requires withdrawal and reassessment for subintimal passage, dissection or extravascular position.
Persistent oozing, expanding haematoma, bruit, falling haemoglobin or hypotension suggests failed haemostasis, pseudoaneurysm, arteriovenous fistula or concealed retroperitoneal bleeding.
New pulse loss, coolness, delayed capillary refill, pain, paraesthesia or weakness beyond the access site may follow thrombosis, embolus, dissection or an occlusive closure device and requires urgent action.
The angiogram must distinguish culprit supply from normal branches, collaterals and shunts; apparent extravasation, pseudoaneurysm filling or pathological blush helps define what to occlude and what to preserve.
Unexpected embolic reflux, passage through a shunt, loss of normal branch opacification or abrupt symptoms in another vascular territory indicates unintended delivery and may cause irreversible infarction.
03Assessment and interpretationHow to gather information, assess the situation and recognise uncertainty.
Consider the information, its meaning and its limitations before deciding what follows.
- 01
Pre-procedure CTA, MRA or duplex ultrasound - Why
- Map target and access anatomy, disease, tortuosity, aneurysm, stenosis, occlusion and possible collateral routes.
- Interpretation and limitations
- Imaging helps choose side and entry vessel, predicts catheter reach and rescue options, but interval thrombosis, spasm and haemodynamic change can alter anatomy by procedure time.
- 02
Real-time ultrasound at the puncture site - Why
- Confirm patency and guide the needle into the intended vessel while avoiding bifurcation, plaque, vein and nearby structures.
- Interpretation and limitations
- Follow the needle tip in short or long axis and confirm intraluminal entry; blood colour or pulsatility alone is unreliable in shock, hypoxaemia or venous hypertension.
- 03
Digital subtraction angiography - Why
- Define the culprit lesion, inflow, outflow, collateral supply, shunts and branches at risk before treatment.
- Interpretation and limitations
- Negative angiography does not always exclude intermittent haemorrhage; selective runs and correlation with CTA may reveal small or variant vessels, while motion and subtraction artefact can mislead.
- 04
Completion angiography - Why
- Assess the intended embolic or reconstructive endpoint and screen for dissection, reflux, thrombosis or non-target vessel loss.
- Interpretation and limitations
- Interpret against the pre-agreed aim: haemostasis may require no further extravasation with markedly reduced target flow, whereas complete stasis can be excessive when essential tissue perfusion must remain.
- 05
Post-access duplex ultrasound - Why
- Investigate pain, swelling, bruit, poor pulses or unexplained anaemia after arterial puncture.
- Interpretation and limitations
- It can identify haematoma, pseudoaneurysm flow, arteriovenous fistula, thrombosis, dissection and distal waveform change; CT angiography is useful when bleeding is deep or retroperitoneal.
04Worked approachesCases with ordered reasoning, an action and a check of the outcome.
01Worked case: bleeding pseudoaneurysmAccess and embolise with flow preservationA haemodynamically supported patient has active upper-abdominal bleeding on CTA from a small branch pseudoaneurysm; the parent artery supplies viable tissue through limited collaterals.+
- 1Define the clinical aim as urgent haemostasis while preserving parent-artery flow, review CTA for access vessels, culprit branch, inflow and outflow, and activate transfusion and surgical backup appropriate to the physiology.
- 2Use real-time ultrasound to puncture a suitable common femoral artery segment, pass the wire gently under fluoroscopy and place a sheath after confirming intraluminal position; document baseline distal pulses.
- 3Perform selective angiography and advance a microcatheter close to the pseudoaneurysm without crossing or injuring it, checking for non-target branches and choosing a focal mechanical agent whose size and deployment can be controlled.
- 4Occlude the relevant inflow and, when anatomy permits, outflow around the pseudoaneurysm rather than filling the sac blindly; pause before each deployment and maintain catheter stability.
- 5Verify exclusion of the pseudoaneurysm and cessation of extravasation with preserved essential parent flow, then remove access and achieve haemostasis.
- 6Recheck observations, haemoglobin trend, abdominal findings, access site and distal perfusion; recurrent instability triggers urgent repeat imaging or angiography because collateral rebleeding can occur.
02Access strategyChoose an entry vessel deliberatelyAn endovascular intervention can technically be approached from more than one access site.+
- 1Compare the target angle, distance, aortic and peripheral disease, device length and sheath diameter for femoral, radial and alternative routes.
- 2Prioritise an artery that is patent, visible, safely puncturable and compressible, and consider how failure would be rescued.
- 3Use ultrasound for puncture, avoid diseased or branching segments and confirm wire course before dilation.
- 4Plan haemostasis and post-procedure mobilisation before choosing access, because closure and surveillance are part of the access decision.
03Embolic selectionMatch the agent to flow and endpointSelective angiography confirms a target but several classes of embolic agent could be used.+
- 1Decide whether occlusion must be temporary or permanent, proximal or distal, focal or bed-level, and whether parent-vessel preservation is essential.
- 2Assess flow velocity, vessel size, tortuosity, catheter stability, collaterals and arteriovenous shunts that could carry material beyond the target.
- 3Choose coils or plugs for controlled focal occlusion, particles for distal vascular-bed treatment, gelatin for temporary effect, or a liquid agent for penetration only when anatomy and operator expertise permit.
- 4Deliver incrementally under continuous observation, stopping for reflux, loss of catheter position, pain or an unexpected change in flow, then verify the endpoint with angiography.
04Access complicationRestore haemostasis and perfusionAfter sheath removal, a patient develops a painful swelling or reduced distal pulse.+
- 1Apply direct control of external bleeding, resuscitate if needed and compare the access site and distal neurovascular examination with baseline.
- 2Use duplex for superficial complications and CT angiography or immediate angiography when deep bleeding, dissection or occlusion is suspected.
- 3Treat according to mechanism with compression, thrombin treatment of a suitable pseudoaneurysm, endovascular repair, thrombectomy or surgery through senior vascular planning.
- 4Repeat perfusion, haemoglobin and wound checks after treatment and document mobility and discharge restrictions.
05Feedback, follow-up and evidenceReview outcomes, seek feedback and identify what to improve.
- Document access-site appearance and palpation, distal pulses, capillary refill, limb temperature, sensation and motor function before intervention and after sheath removal or closure.
- Use serial pulse, blood pressure, pain and haemoglobin assessment to detect concealed bleeding; a dry dressing does not exclude retroperitoneal haemorrhage.
- Observe the embolised organ for expected and unexpected effects, including pain, fever, biochemical injury, ischaemia, abscess or loss of function according to the treated territory.
- Record catheter and embolic materials, target branches, angiographic endpoint, contrast volume, radiation indicators and any non-target concern in the procedure report.
- Arrange ultrasound, CTA, MRA or clinical follow-up according to the lesion: pseudoaneurysm exclusion, tumour response and collateral-prone haemorrhage require different surveillance.
- Escalate recurrent bleeding, new neurological findings, worsening abdominal signs, oliguria, limb ischaemia or expanding haematoma without waiting for routine review.
06Special situationsVariants, exceptions and circumstances that change the usual approach.
Puncture site predicts rescue
A high femoral puncture risks bleeding above the inguinal ligament where compression is ineffective, while a low puncture increases pseudoaneurysm and branch injury risk.
Blood return is insufficient
Free-flowing blood suggests vessel entry but does not prove the intended artery or safe wire course; ultrasound and fluoroscopic confirmation remain essential.
Proximal occlusion may recruit collaterals
If embolisation stops only the main inflow, distal tissue can be reperfused through communicating vessels; the strategy must reflect the vascular network.
Particle size changes destination
Smaller particles penetrate further but increase tissue-ischaemia and shunt risk; larger particles lodge proximally and may leave distal pathological vessels supplied.
Liquid agents amplify technique
Their penetration can treat tortuous complex channels, but injection speed, dilution, reflux and catheter entrapment make operator familiarity central to safety.
Clinical haemostasis outranks the image
A satisfactory completion run must be followed by stabilisation of physiology and haemoglobin; vasospasm or intermittent bleeding can create false reassurance.
07Common pitfallsFrequent interpretation and management errors.
- 01
Selecting an access site by habit without reviewing plaque, bifurcation, prior surgery, device reach and haemostasis options.
- 02
Dilating a tract before confirming that the wire follows a safe intraluminal course.
- 03
Relying on a closure device to compensate for an unsafe puncture location.
- 04
Embolising a suspected branch before mapping normal organ supply, shunts and dangerous collaterals.
- 05
Using the smallest particles for greater penetration without accounting for necrosis and non-target passage.
- 06
Continuing injection when reflux appears or catheter position changes.
- 07
Assuming no angiographic extravasation excludes intermittent bleeding or guarantees durable haemostasis.
- 08
Checking only the wound after arterial access and omitting distal neurovascular observations.