The endovascular playbook

Getting in: vascular access

Every endovascular case starts with a needle in a vessel, and almost all of it rests on one idea, the Seldinger technique. Where and how the artery is entered decides much of what can go wrong afterward.

You puncture the artery with a needle, pass a guidewire through the needle into the lumen, remove the needle while leaving the wire in place, and then slide a sheath or catheter over the wire. The wire is the rail that everything else rides on. The cardinal rules are that you never let go of the wire and never advance anything against resistance.

Most operators start with a micropuncture set: a 21-gauge needle that takes a 0.018 inch wire, then a small coaxial dilator that converts the access to a standard 0.035 inch wire. A misplaced stick with a small needle does far less harm than one with a large needle.

The common femoral artery, the default door

The common femoral artery is the workhorse access site because it is large and, crucially, it lies over the femoral head, so it can be compressed against bone afterward to stop bleeding. The safe puncture is below the inguinal ligament and above the femoral bifurcation, aiming for the artery as it crosses the middle of the femoral head on fluoroscopy. The skin crease is a poor guide; in obese patients it often lies below the bifurcation.

• Retrograde access. The puncture points against the direction of flow, with the wire heading up toward the aorta. This is the setup for aortography, for treating the aorta and iliacs, and for crossing over to the other leg.
• Antegrade access. The puncture points with the direction of flow, with the wire heading down the same leg. It is used to treat disease in the thigh and below on the same side.
• Contralateral “up and over.” One common femoral is punctured retrograde, a catheter is walked up and over the aortic bifurcation, and the wire comes down the opposite leg to treat it.

Radial and brachial access

The radial artery is increasingly used for visceral and some peripheral work because it has a much lower bleeding and access-site complication rate and lets the patient sit up and walk right away. The left radial is usually preferred for work below the diaphragm: it is a shorter route to the legs, and the catheter enters the arch at the left subclavian without crossing the origins of the innominate and left carotid arteries. Its limits are a small artery, which caps the sheath size, and reach, because many devices are too short to get from the wrist to below the knee.

Before radial access, many operators confirm a dual blood supply to the hand with an Allen or Barbeau test, so that the ulnar artery and palmar arch can perfuse the hand if the radial occludes, although how well these tests predict hand ischemia is debated. Heparin and an antispasmodic “cocktail” are given to prevent spasm and radial artery occlusion, and at the end a compression band is weaned off over a couple of hours while keeping the artery open.

The brachial artery is an alternative but carries a higher risk of median nerve injury and of a hematoma that compresses the nerve within the tight brachial sheath, so it is used more selectively. Large-bore upper-limb access for complex aortic work usually goes through the axillary or brachial artery, by cutdown or a carefully closed puncture.

Wires, catheters and sheaths

These are the hand tools of the field, and understanding what each does makes a case legible. Two ideas organize everything: French sizing, and the difference between a wire, a catheter and a sheath. This section is the primer; the named products are catalogued on Wires, catheters and devices.

Guidewire

The rail. It goes first, crosses the lesion, and everything else travels over it. Its diameter is measured in inches (0.035, 0.018, 0.014).

Catheter

A long hollow tube that rides over the wire to steer it, support it, inject contrast or reach a branch. Sized in French by its outer diameter.

Sheath

A tube with a hemostatic valve that sits in the puncture, holds it open, and lets catheters and devices go in and out without bleeding or losing access. Sized in French by its inner diameter.

Guide catheter

A larger, stiffer catheter that reaches further than a short sheath and gives backup for pushing a device across a tough lesion. Like other catheters, it is sized by its outer diameter.

• 1 Frabout 0.33 mm, so 3 French is about 1 mm
• 0.035 inthe everyday workhorse wire platform
• 0.018 / 0.014 insmall-vessel platforms for tibial and pedal work and low-profile devices

Guidewires

Wires differ in diameter, length, stiffness, tip shape and coating. The everyday workhorse is the 0.035 inch system, while smaller 0.018 and 0.014 inch wires are used for the small tibial and pedal vessels and for low-profile devices. Length matters too: an exchange-length wire is long enough to hold onto while a whole catheter is withdrawn over it, roughly twice the length of the catheter.

• Hydrophilic wires. Called “glide” wires in the room, they have a slippery coating and an angled or steerable tip, ideal for crossing tight or tortuous lesions. The same slipperiness lets them back out, dissect or perforate, so they are usually exchanged for a more supportive wire before bulky devices are delivered, and they are never pulled back through a metal access needle, which can shear off the coating.
• Stiff and super-stiff wires. Wires such as the Amplatz, and the Lunderquist for aortic work, provide the rigid rail needed to track a bulky stent graft through a tortuous iliac system. Exchanging a soft crossing wire for a stiff delivery wire, through a catheter so the wire position is never lost, is a recurring step.
• Soft, atraumatic wires. Wires such as a Bentson, with a long floppy tip, are used where you want to avoid injuring the vessel, for example on the first pass up a diseased iliac.

Every balloon and stent is built for one wire platform, and its label lists the wire it rides on, the smallest sheath it fits through, and its shaft length. An over-the-wire device carries the wire through its whole length, which gives better push. A rapid-exchange (monorail) device lets the wire exit a short distance from the tip, so a shorter wire can be used and one person can swap devices.

Catheters

Catheters either inject contrast or select a branch. Flush catheters with a coiled pigtail tip and many side holes sit in a large vessel and deliver a big power-injected bolus for an aortogram without whipping around. Selective catheters have an end hole and preformed shapes designed to hook into specific branches: an angled or Berenstein tip for gentle selection, a Cobra shape for downgoing visceral vessels, and reverse-curve shapes such as the Simmons (Sidewinder) or SOS Omni for sharply angled or upgoing origins. Recurved shapes are also how the opposite iliac is hooked when going up and over. Low-profile support (crossing) catheters follow the wire into an occlusion to give it push.

Selective injections are made at lower rates and volumes than flush runs. A high-rate power injection through an end-hole catheter sitting in a small branch can dissect it.

Sheaths and guides

A sheath holds the puncture open and lets you exchange catheters and devices without losing access or bleeding. A guide catheter is a longer support tube that reaches further and gives backup to push a device across a tough lesion. Long sheaths do the same job from the groin: a crossover sheath parked over the aortic bifurcation supports work in the opposite leg. Most cases progress from a small diagnostic sheath to a larger one once the plan and the device size are settled.

Because sheaths are named by their inner diameter and guides by their outer diameter, a guide usually needs to be about one French size larger than the sheath the same device would need. Check the device label rather than relying on the rule.

Making the pictures: angiography and DSA

An angiogram is a real-time X-ray movie of contrast moving through vessels. The refinement that makes it so clear is digital subtraction angiography (DSA), which takes a plain “mask” image of the field and subtracts it from the contrast images, erasing bone and soft tissue so only the contrast-filled vessels remain.

Techniques you will hear named

• Road-mapping. A stored contrast image is overlaid on the live fluoroscopy so the operator can steer a wire along a faint map of the vessel without continuous contrast.
• Angled projections. A bifurcation or an aneurysm neck often hides on a straight-on view and opens up only when the C-arm is angled. The common iliac bifurcation is usually best seen in a contralateral oblique and the common femoral bifurcation in an ipsilateral oblique. The celiac and superior mesenteric origins, which arise from the front of the aorta, are seen best on a lateral view.
• Bolus chase and stepping runoff. A single injection is followed down the legs as the table moves, or a series of stations is imaged from pelvis to foot.
• Pressure gradients. Measuring pressure above and below a borderline lesion, sometimes after a vasodilator, helps decide whether an iliac stenosis matters hemodynamically. Thresholds vary between operators.

A diagnostic aortogram with runoff

1. Access and sheath. Usually a retrograde common femoral puncture on the less affected side, so the same access can go up and over to treat the worse leg.
2. Aortogram. A flush catheter at about the level of the renal arteries (around L1) shows the renal arteries, the infrarenal aorta and the iliacs.
3. Pelvis. The catheter is pulled down to just above the aortic bifurcation for the iliac and femoral bifurcations, with obliques as needed.
4. Runoff. Images down both legs to the feet, including the tibial vessels and the pedal arch, comparing the two sides.
5. Selective views. If treatment is planned, a selective catheter goes up and over for closer, lower-contrast pictures of the target leg.

IVUS and adjunct imaging

An angiogram is a silhouette of the lumen in one plane. Intravascular ultrasound and three-dimensional imaging in the room fill in what the silhouette misses: the true size of the vessel, what the wall is made of, and where the branches are.

Intravascular ultrasound (IVUS)

IVUS is a catheter with an ultrasound transducer at its tip, run over a wire to give cross-sectional images from inside the vessel. Small catheters ride 0.014 or 0.018 inch wires for leg arteries; larger ones on 0.035 inch wires image the aorta, the iliacs and the large veins.

• Sizing. IVUS measures the true diameter and cross-sectional area of the lumen and of the healthy reference segment. Angiography sees only the lumen in one plane and tends to under-size, so balloons and stents chosen by IVUS are often larger.
• Plaque and calcium. It shows how much of the circumference is calcified and how deep, which guides whether vessel preparation such as atherectomy or lithotripsy is needed.
• Wire position. It confirms whether a wire is in the true lumen or subintimal, which matters after crossing an occlusion and when treating aortic dissection, where the stent graft must go into the true lumen.
• Checking the result. After treatment it shows residual narrowing, dissection, and whether a stent is fully expanded and against the wall.
• Less contrast. It can replace some contrast runs, which helps patients with kidney disease.

Why IVUS dominates venous stenting

Iliac vein compression (May-Thurner and other non-thrombotic iliac vein lesions) and post-thrombotic scarring are poorly seen on venography. A compressed iliac vein is flattened between the artery and the spine and spreads sideways, so a front-on venogram can make it look wide and normal; collaterals may be the only clue. IVUS shows the true cross-section, so it is used to diagnose the lesion, choose the stent diameter, and pick landing zones that cover the whole diseased segment. In the VIDIO study, venography missed a meaningful share of lesions that IVUS found. A cross-sectional area reduction of about 50 percent or more is commonly treated as significant, though thresholds vary.

Cone-beam CT and fusion imaging

• Cone-beam CT. The C-arm spins around the patient to build a CT-like three-dimensional image on the table. It is used to check stent graft and bridging stent position and look for endoleak at the end of complex aortic repairs, and to map feeding vessels before embolization. It adds radiation dose, so it is used deliberately.
• Fusion imaging. The preoperative CTA is turned into a 3D model and overlaid on live fluoroscopy, registered to the bones or to a cone-beam CT. It marks the renal and visceral origins for fenestrated and branched repair and reduces contrast and radiation. Stiff wires and devices straighten and shift the aorta, so the overlay drifts and has to be checked and corrected.

Respecting radiation and contrast

The two hazards unique to this room are ionizing radiation and iodinated contrast. Both are asked about constantly, partly because they are safety issues you are expected to take seriously from day one.

Radiation safety and ALARA

The governing principle is ALARA, keeping dose “as low as reasonably achievable” for both the patient and the team. Dose is controlled along three classic levers and a few practical habits.

• Inverse-square law. Doubling your distance from the source quarters your exposure, which is why simply stepping back during an injection is one of the most effective things you can do.
• Geometry. Keep the X-ray tube under the table and the detector close to the patient, and collimate the beam to the area of interest, which lowers dose and improves the image. Magnification and steep angles raise dose.
• Scatter. Most of the radiation reaching the team is scattered off the patient, and it is highest on the side where the beam enters, the tube side. On a steep oblique or lateral view, stand on the detector side.
• Hands out of the beam. Hands near the field during fluoroscopy can be in the primary beam, not just scatter.

• 50 mSvUS annual occupational whole-body dose limit
• 5 mSvUS limit to the embryo or fetus over a declared pregnancy
• About 2 Gypeak skin dose at which transient skin reddening can begin
• About 5 Gyreference air kerma often used to trigger patient skin follow-up (local thresholds vary)

Iodinated contrast

Iodinated contrast makes vessels visible but carries two main risks, plus one medication interaction you will be asked about.

Contrast-associated kidney injury

A rise in creatinine, usually within 48 to 72 hours. Risk is highest with chronic kidney disease (particularly an eGFR below 30; European guidance uses about 45 when intra-arterial contrast reaches the kidneys first, as in an aortogram), diabetes with kidney disease, dehydration, hypotension, and large or repeated contrast loads. The mitigations are to identify at-risk patients, give isotonic IV fluid when indicated, minimize the contrast volume, and avoid other nephrotoxins. In the PRESERVE trial, bicarbonate and N-acetylcysteine were no better than saline and placebo, so they are no longer recommended.

Allergic-like reaction

From hives to anaphylaxis. A patient with a prior allergic-like reaction to iodinated contrast is generally premedicated with a corticosteroid and an antihistamine, and breakthrough reactions still happen, so the team stays ready. A shellfish or “iodine” allergy is not a contrast allergy and is not by itself a reason to premedicate.

Metformin

Contrast does not interact with metformin directly, but kidney injury can lead to metformin accumulation and lactic acidosis. Under ACR guidance, patients with an eGFR of 30 or more and no acute kidney injury can continue it; those with acute kidney injury or an eGFR under 30 hold it from the time of contrast for 48 hours and restart once kidney function is confirmed stable.

Planning a peripheral intervention

Most of a peripheral intervention is decided before the needle goes in: what is being treated, from which access, how the lesion will be crossed, and what will be done once it is. Knowing the plan lets you follow the case and anticipate its problems.

Read the imaging as inflow, outflow and target

Whether the source is a duplex, a CTA or an old angiogram, describe it in the same three parts.

Inflow

The aorta, iliacs and common femoral artery. Inflow disease is fixed first, because a distal repair fed by a stenotic iliac will fail. Common femoral disease is classically treated with open endarterectomy rather than a stent, often combined with iliac stenting or distal work as a hybrid procedure.

Outflow

The profunda, superficial femoral and popliteal arteries. Note stenosis versus occlusion, length, calcium, and where the vessel reconstitutes below an occlusion.

Target and runoff

The tibial vessels and pedal arch. In chronic limb-threatening ischemia the question is which tibial artery can carry straight-line flow to the foot, ideally to the region of the wound.

• Duplex. Cheap and safe, and it maps the vein for a possible bypass at the same visit. A peak systolic velocity ratio of about 2 or more across a segment suggests a stenosis of at least 50 percent. It is operator-dependent and difficult in the obese abdomen.
• CTA. Shows the whole tree, the calcium and the access vessels, and is the planning study for the aorta. Heavy calcium blooms in small tibial vessels and can make them look worse than they are.
• Catheter angiography. Still the reference standard for tibial and pedal anatomy, and usually done in the same sitting as treatment.

For chronic limb-threatening ischemia, the Global Vascular Guidelines frame the decision as PLAN: patient risk, limb severity (the WIfI stage) and anatomic pattern (the GLASS stage, which grades femoropopliteal and infrapopliteal disease along the target artery path). The older TASC II A to D classes still come up for aortoiliac and femoropopliteal lesions. For patients with a usable great saphenous vein, the BEST-CLI trial favored bypass, so “endovascular first” is no longer automatic. See CLTI, bypass and the staging systems.

Choosing access

Crossing the lesion

Stenoses are usually crossed easily. Chronic total occlusions are the challenge, and the strategy escalates.

1. Intraluminal. A wire, supported by a catheter, is worked through the occlusion while staying in the true lumen. This is preferred where possible because it keeps the vessel's structure and the options for later.
2. Subintimal. When that fails, the wire is deliberately passed into the plane within the vessel wall, often as a loop of hydrophilic wire, tracked along the occlusion and brought back into the true lumen beyond it (subintimal angioplasty). The danger is failing to re-enter and extending the dissection past the point of reconstitution.
3. Re-entry device. If the wire will not come back into the true lumen, a re-entry catheter fires a small needle, aimed under fluoroscopy or IVUS, from the subintimal plane into the true lumen just below the occlusion.
4. Retrograde (SAFARI-type) approach. A second access below the occlusion (pedal, tibial or popliteal) lets a wire cross from below. The two channels are connected, or the retrograde wire is snared and pulled out through the femoral sheath to make a through-and-through “flossing” wire, and treatment is delivered from the femoral side so the small distal access stays small. SAFARI stands for subintimal arterial flossing with antegrade-retrograde intervention.

Vessel preparation, then definitive therapy

1. Confirm the true lumen beyond the lesion. A small contrast injection through the catheter past the lesion, or IVUS.
2. Anticoagulate. Systemic heparin, weight-based, once the decision to intervene is made and before treatment, with the dose and ACT target set by the operator and local protocol.
3. Prepare the vessel. Predilation with an undersized plain balloon, a scoring or cutting balloon, atherectomy, or intravascular lithotripsy for heavy calcium, so the lesion expands evenly and dissection is limited.
4. Definitive therapy. A drug-coated balloon, a stent (bare, drug-eluting or covered), or both. Many operators stent provisionally, only for a flow-limiting dissection or a significant residual stenosis (often defined as more than 30 percent) after balloon angioplasty.
5. Completion imaging. Angiography of the treated segment and of the runoff to the foot, compared with the baseline, to catch dissection, residual narrowing and distal embolization.
6. Antithrombotic plan. Commonly dual antiplatelet therapy for a period after stenting, or low-dose rivaroxaban (2.5 mg twice daily) with aspirin after lower-extremity revascularization, based on VOYAGER PAD. The regimen and its duration are the attending's call and belong in the post-procedure note.

The toolkit: balloons, stents and atherectomy High yield

Once you are across a lesion with a wire, a small family of devices does the actual treating. This section covers what each family does and when it is chosen; the named products are on balloons, stents and stent grafts.

Balloon angioplasty

A balloon is tracked over the wire to the lesion and inflated to crack and stretch the plaque, often called plain balloon angioplasty (PTA, for percutaneous transluminal angioplasty). Balloons are sized to the healthy reference vessel, roughly one to one, and inflated with dilute contrast using a pressure syringe (an inflation device) read in atmospheres. Each balloon has a nominal pressure, at which it reaches its labeled diameter, and a rated burst pressure, which should not be exceeded. Non-compliant balloons hold their size at high pressure; compliant balloons keep growing as they fill and are used for gentle molding, such as of a stent graft's seal zones.

• Drug-coated balloons. These transfer an antiproliferative drug, most often paclitaxel, to the vessel wall to reduce restenosis, especially in the femoropopliteal segment. A 2018 meta-analysis raised a late mortality signal for paclitaxel devices; after reviewing further data, the FDA concluded in 2023 that the evidence does not support an excess mortality risk. Sirolimus-coated balloons are a newer alternative whose place alongside paclitaxel is still being defined.
• Cutting and scoring balloons. Small blades or wires on the balloon score resistant, calcified or recurrent lesions so they open at lower pressure.
• Intravascular lithotripsy. A balloon that emits pressure waves to fracture calcium in the vessel wall before definitive therapy.

Stents

The single most asked endovascular concept is the difference between the two stent families and where each belongs.

A covered stent (stent graft) is a stent lined with fabric. It is used to exclude an aneurysm or a pseudoaneurysm, to seal a perforation or rupture, in complex aortoiliac occlusive disease, and sometimes to treat recurrent in-stent restenosis. Drug-eluting stents release an antiproliferative drug over time and are used in the femoropopliteal segment and, borrowed from coronary practice, in short tibial lesions.

Atherectomy

Atherectomy physically removes or debulks plaque rather than just displacing it, using directional, rotational, orbital or laser devices. It is used mainly for heavily calcified lesions and in-stent restenosis, and to prepare a vessel before angioplasty. The chief hazard to know is distal embolization of the liberated debris, sometimes managed with an embolic protection filter. The evidence that atherectomy improves outcomes over angioplasty alone is limited, and high-volume use of it has drawn scrutiny.

Aortic stent grafts: EVAR and TEVAR

The largest endovascular operations are the aortic ones. EVAR (endovascular aneurysm repair) treats the abdominal aorta and TEVAR treats the thoracic aorta, in both cases by deploying a fabric-covered stent graft that creates a new internal channel and excludes the aneurysm sac from the circulation.

What makes an aneurysm suitable

A stent graft needs healthy vessel to seal against at each end, the landing (sealing) zones. For EVAR the key constraints are an adequate infrarenal neck (enough length below the renal arteries, an acceptable diameter, limited angulation, and not too much thrombus or calcium) and iliac arteries large and straight enough to deliver the device. Typical instructions for use ask for roughly 10 to 15 mm of neck length, a neck diameter up to about 32 mm and angulation under about 60 degrees, but each device has its own limits. When the neck is hostile, standard EVAR will not seal, which is the reason fenestrated and branched devices exist. Repair thresholds are on abdominal aortic aneurysm.

How EVAR goes, in brief

1. Access both groins. Surgical cutdown, or a percutaneous “pre-close” technique in which suture-mediated closure devices are deployed before the puncture is enlarged. Large sheaths go in over stiff wires and systemic heparin is given.
2. Deploy the main body. Position the graft under fluoroscopy just below the lowest renal artery, confirming the level with an aortogram, and deploy so the fabric seals against the neck.
3. Cannulate the contralateral gate and complete the seal. Catheterize the short stump of the bifurcated graft from the other groin, extend a limb into each iliac, preserving at least one internal iliac artery where possible, and balloon the seal zones and junctions.
4. Completion angiogram. Confirm exclusion of the sac, and look specifically for an endoleak and for kinked or narrowed limbs.
5. Close and check. Close the arteriotomies and check pulses or Doppler signals in both legs before the patient leaves the room.

Afterward, watch the groins, both legs (a kinked or occluded graft limb presents as a cold leg or new claudication), the kidneys after contrast, and for post-implantation syndrome, an expected, self-limited fever and leukocytosis in the first days that still requires infection to be considered. Endoleaks are the late failure mode: types I and III are high-pressure leaks that are repaired, and type II, the most common, is usually watched unless the sac grows. The full classification is on EVAR and endoleaks.

TEVAR

TEVAR treats descending thoracic aneurysms, complicated type B dissection (rupture, malperfusion, refractory pain or hypertension, or rapid expansion) and increasingly selected uncomplicated type B dissections with high-risk features, and blunt traumatic aortic injury, classically at the isthmus just distal to the left subclavian, where it has largely replaced open repair. In dissection the graft must go into the true lumen to cover the entry tear and re-expand it. Which arch branches the graft covers depends on its landing zone; see aortic landing zones.

Aortic landing zones

Stent grafts are described by where they land. The zone tells you which branches the fabric covers, and therefore what has to be done to keep those branches perfused.

The Ishimaru arch zones, 0 to 4

The Ishimaru map divides the arch and proximal descending aorta at the branch origins. The zone where the proximal end of the graft lands is its proximal seal zone, and every branch that arises from the aorta the fabric crosses is covered. Most thoracic devices need about 2 cm of healthy, parallel-walled aorta to seal, which is why lesions near the left subclavian so often push the landing zone up into the arch.

Covering the left subclavian

Zone 2 landing is common, because many descending thoracic lesions start close to the left subclavian. Covering it without revascularization risks:

• arm ischemia, usually mild because of collaterals but sometimes disabling;
• posterior circulation stroke, especially with a dominant left vertebral artery;
• spinal cord ischemia, because the left vertebral and internal thoracic arteries feed the cord's collateral network;
• myocardial ischemia when a left internal mammary artery graft supplies the heart.

SVS guidance suggests routine left subclavian revascularization before elective TEVAR that covers it, and considers it essential with a left internal mammary coronary graft, a dominant left or absent right vertebral artery, a functioning left arm dialysis access, or extensive coverage with high spinal cord risk; European guidance also favors revascularization in elective cases. In an emergency (rupture or trauma) the subclavian is often covered and revascularized later only if symptoms develop. The options are a carotid-subclavian bypass or subclavian-to-carotid transposition, or a branched stent graft with a side branch into the subclavian. When a bypass is done, the subclavian origin is plugged or covered so the sac cannot refill backward through it.

The SVS/STS zones, 0 to 11

The 2020 SVS/STS reporting standards for aortic dissection extended the map down the whole aorta, so that a dissection's extent or a repair's seal zones can be stated in one shorthand. Zones 0 to 3 match the arch zones above. In this system a type A dissection has its entry tear in zone 0 and a type B dissection has its entry tear in zone 1 or beyond, written with the proximal and distal extent (for example, B3,10 for a type B dissection from zone 3 to the common iliacs). Fenestrated and branched repairs are described the same way: “sealing in zone 6” means above the superior mesenteric artery.

Complex aortic repair: FEVAR and BEVAR

When the aneurysm reaches the visceral and renal arteries, a plain tube would cover their origins and infarct the kidneys and gut. Complex endovascular repair moves the seal zone up the aorta while keeping those branches open.

Fenestrated grafts (FEVAR) have reinforced holes aligned to each branch origin, through which small covered bridging stents are placed into the renal and mesenteric arteries. They suit juxtarenal and pararenal aneurysms, where the graft body sits close to the aortic wall. Branched grafts (BEVAR) carry actual side branches that bridge across a wider aorta to each vessel, for more extensive thoracoabdominal disease. Many devices are custom-made from the patient's CTA, which takes weeks; off-the-shelf branched designs and, at some centers under institutional protocols, surgeon-modified grafts made on the back table fill the gap for urgent cases.

These are long cases, done at experienced centers, often with fusion imaging and cone-beam CT. They cover more aorta, so the spinal cord risk rises with the extent of repair, and the bridging stents add their own failure modes: branch stenosis or occlusion, and leaks at the connections between the branch stents and the main graft. Surveillance is at least as demanding as after standard EVAR.

Clot management: thrombolysis and thrombectomy

For acute clot, whether a clotted bypass, an acutely ischemic limb, an iliofemoral DVT or a pulmonary embolism, two endovascular strategies exist, and they are often combined.

• Catheter-directed thrombolysis. A multi-sidehole catheter is threaded into the clot and a fibrinolytic drug (such as tissue plasminogen activator) is infused directly into it over hours, dissolving the thrombus while sparing the patient a full systemic dose. It also tends to reveal the underlying lesion that caused the clot, which can then be treated. The patient is monitored in an ICU or step-down bed, with serial hemoglobin and fibrinogen checks, and comes back for a repeat angiogram (a “lysis check”) after several hours or the next morning.
• Mechanical and pharmacomechanical thrombectomy. Devices aspirate or macerate clot, either alone for speed or combined with a lytic. Aspiration thrombectomy is increasingly used for acute limb ischemia and for selected pulmonary emboli. The named devices are on thrombectomy devices.

Where each fits

Acute limb ischemia

Rutherford category I and IIa limbs have time for catheter-directed lysis, which suits thrombosis of a native artery or a bypass graft and unmasks the culprit lesion. Category IIb limbs need revascularization now, by open embolectomy or rapid mechanical thrombectomy. Category III limbs are not salvageable, and restoring flow can be dangerous. See acute limb ischemia and embolectomy.

Iliofemoral DVT

Early thrombus removal is considered for selected patients with acute iliofemoral DVT (recent onset, low bleeding risk, good functional status) and urgently for phlegmasia. ATTRACT found no reduction in post-thrombotic syndrome overall, though iliofemoral patients had less moderate-to-severe disease; CAVA found no benefit, so selection matters. An underlying iliac vein compression is usually stented after clearance, sized by IVUS. See venous thromboembolism.

Pulmonary embolism

Catheter-directed lysis or aspiration is used for high-risk (massive) PE when systemic lysis is contraindicated or has failed, and for selected intermediate-high-risk PE that is deteriorating, usually through a multidisciplinary PE response team.

Embolization and IVC filters

Sometimes the goal is to stop flow rather than restore it, either by deliberately occluding a vessel or by catching clot before it reaches the lungs.

Embolization

Embolization deliberately occludes a vessel using coils, vascular plugs, particles or liquid agents. Vascular surgeons use it to treat a type II endoleak, to control bleeding (trauma, gastrointestinal bleeding or a pseudoaneurysm), to occlude an internal iliac artery before some aortic work, and to treat arteriovenous malformations and pelvic venous reflux.

Coils

Metal spirals, often with thrombogenic fibers, pushed or detached at a precise spot for permanent occlusion of a named vessel.

Vascular plugs

Self-expanding nitinol mesh plugs that occlude a larger vessel with a single device, such as an internal iliac artery or the left subclavian origin.

Particles

Microspheres or polyvinyl alcohol particles that lodge in small distal vessels; used for tumors and diffuse small-vessel bleeding rather than named arteries.

Gelatin sponge

A temporary agent that recanalizes over weeks, useful in trauma.

Liquid agents

Glue (cyanoacrylate) and other liquid embolics that cast the vessel or the nidus of a malformation; used for some endoleaks, malformations and bleeding in difficult anatomy. Thrombin injected under ultrasound into a femoral pseudoaneurysm works on the same principle.

Inferior vena cava filters

An IVC filter is a device placed in the inferior vena cava to catch emboli from the legs and pelvis. Its clear indication is acute proximal DVT or PE in a patient who cannot be anticoagulated, because of active bleeding or a complication that forces anticoagulation to stop. Recurrent PE despite truly therapeutic anticoagulation is a traditional but more debated indication; adherence, dosing and a change of agent are checked first. A filter does not treat the clot and does not replace anticoagulation once it becomes safe. Trials have not shown benefit from adding a filter to anticoagulation (PREPIC2) or from prophylactic filters in patients without VTE, such as after major trauma.

Filters are placed from the femoral or jugular vein, usually infrarenally with the top just below the lowest renal vein; a suprarenal position is reserved for special situations such as thrombus reaching the renal veins.

Getting out: closure and access complications High yield

At the end of the case the arteriotomy has to be sealed, and most endovascular complications happen right here. Recognizing them quickly is squarely a trainee's job on rounds and overnight.

Closing the hole

• Manual compression. Firm pressure over the arteriotomy, which in a retrograde puncture lies a centimeter or two above the skin nick, typically for 15 to 20 minutes for a small sheath once the heparin effect has fallen to the protocol threshold, and longer for larger sheaths. Still the standard for small sheaths and whenever a closure device is unsuitable.
• Closure devices. Suture-mediated systems, extravascular plugs (collagen or a sealant) and clips. They let the patient sit up and walk sooner, but they have not clearly reduced complications. They need a common femoral puncture above the bifurcation in a vessel large enough and not too calcified, which is why a sheath angiogram in an ipsilateral oblique view is taken before deployment.
• Large-bore closure. For EVAR and TEVAR sheaths, two suture devices are placed before the hole is enlarged (“pre-close”) and tied at the end; dedicated large-bore plug devices also exist. A failed pre-close becomes a cutdown and open repair.
• Radial. A compression band, inflated just enough to stop bleeding while keeping flow through the artery (patent hemostasis), then gradually deflated.

The named closure devices are on closure devices.

Access-site complications

Before and after an angiogram

Most of what a resident does for an endovascular patient happens outside the suite: getting them ready safely, then catching complications afterward. What follows is the common academic-center pattern; the specifics are set by local protocol and the operator.

Before

• Indication and plan. Team Document the indication, the planned access and the intended treatment in the history and physical or pre-procedure note.
• Consent. Operator or delegate, per policy The procedure, its risks (bleeding and access-site injury, contrast reaction and kidney injury, vessel injury or embolization, radiation, and the possibility of further or open surgery), benefits and alternatives, plus the sedation or anesthesia plan.
• Baseline exam. You Both groins, and pulses or Doppler signals at every level in both legs, with the ABI if available. Mark the pedal signals with a pen so later checks compare the same spot.
• Labs. You Basic metabolic panel (creatinine, eGFR and potassium), CBC (hemoglobin and platelets), and PT/INR, with aPTT or anti-Xa if the patient is on heparin. Type and screen for larger cases such as EVAR and TEVAR, a pregnancy test when relevant, and glucose in diabetics.
• Antithrombotics. Per protocol and operator Aspirin and usually the P2Y12 inhibitor are continued for peripheral intervention. Warfarin, DOACs, low-molecular-weight heparin and heparin drips are held or continued according to the procedure's bleeding risk, the access size and the reason for anticoagulation. As a common pattern, apixaban or rivaroxaban is stopped one day before a low-bleeding-risk procedure and two days before a high-risk one, with longer holds for dabigatran when kidney function is reduced, and the acceptable INR is lower for large-bore access than for a small sheath.
• Contrast allergy. Per protocol For a prior allergic-like reaction, premedicate. The commonly taught elective regimen is prednisone 50 mg by mouth 13, 7 and 1 hour before, plus diphenhydramine 50 mg 1 hour before, with accelerated IV regimens for urgent cases.
• Kidneys. You Identify at-risk patients, hold nephrotoxins such as NSAIDs where possible, order IV isotonic fluid per protocol, and handle metformin per the contrast guidance above.
• Fasting and medications. Per sedation policy NPO follows the sedation or anesthesia policy. ASA guidance allows clear liquids until about 2 hours before and a light meal until 6 hours before, but many units still use NPO after midnight. Morning medications go with a sip of water, and insulin doses are reduced to avoid hypoglycemia while fasting.
• Lines and site. Nursing A working IV, the planned access site clean and intact, and no IV or blood pressure cuff on an arm planned for radial access or carrying a dialysis fistula.

After

• Know the access details. Site and side, sheath size, closure method (manual, device or pre-close), whether a sheath was left in, the heparin given and last ACT, and the antithrombotic plan. These come from the procedure note or the operator.
• Access-site and distal checks. Vitals, the access site and the distal pulses or Doppler signals, commonly every 15 minutes for the first hour, every 30 minutes for the next, then hourly for several hours, per protocol.
• Bedrest. Its length depends on sheath size and closure method. As typical patterns: a few hours flat with the leg straight and the head of the bed low after manual compression of a small femoral sheath; often less after a closure device; longer, sometimes overnight, after large-bore access or if anticoagulation continues; and none after radial access, where the wrist band is weaned instead. The operator's order sets the time.
• Sheaths left in. A sheath left in place, for example during lysis, is pulled when the ACT or aPTT has fallen to the protocol threshold, followed by manual compression and a fresh bedrest clock.
• Hydration and kidneys. IV or oral fluids for at-risk patients as planned, and a repeat creatinine at 48 to 72 hours when the risk is high, which may mean after discharge.
• Medications. Restart home medications, start the post-procedure antiplatelet regimen, restart anticoagulation at the time the operator specifies, and restart metformin per the contrast plan.
• Before discharge. Walk the patient, then recheck the access site and pulses. Teach them to call for bleeding, new swelling, or a cold, numb or painful leg or hand.