4.2 Arterial & Venous Access Sites

Access Site Selection in Modern Cath Labs

Vascular access is Domain B Task 14 on the RCIS outline and the gateway to every diagnostic and interventional procedure. The RCIS participates in site preparation, collateral testing, sheath management, and complication recognition — not independent surgical decision-making, but operational mastery of each route. Site selection balances procedure requirements (sheath size, device profile, anticipated duration), patient anatomy (prior grafts, vascular disease, body habitus), and evidence-based safety (radial-first strategies for ACS/STEMI).

Transradial Arterial Access

Transradial access (TRA) through the radial artery at the wrist (typically 2–3 cm proximal to the radial styloid) has become the default approach for coronary diagnostic and interventional procedures in most high-volume centers. Randomized trials including RIVAL and MATRIX demonstrate reduced major bleeding, vascular complications, and mortality compared with transfemoral access in acute coronary syndrome when operators are experienced.

Collateral circulation testing is mandatory before radial cannulation. The Allen test compresses both radial and ulnar arteries, releases the ulnar artery, and assesses hand reperfusion — but it is subjective. The Barbeau test uses pulse oximetry plethysmography on the thumb during sequential radial and ulnar compression:

Sheath sizes for diagnostic coronary angiography are typically 5–6 Fr; PCI commonly uses 6–7 Fr sheaths. Radial artery spasm is the most frequent procedural obstacle — managed with nitroglycerin, verapamil/diltiazem (institutional cocktail), warm packs, and hydrophilic sheaths. Post-procedure radial artery occlusion (RAO) is minimized with patent hemostasis (TR Band or similar), adequate anticoagulation during the case, and avoiding excessive compression.

Contraindications to radial access include prior coronary bypass using the radial artery as a conduit, Barbeau Type D, dialysis fistula in the target arm, and severe peripheral arterial disease affecting the forearm vessels.

Transfemoral Arterial Access

Transfemoral access (TFA) punctures the common femoral artery (CFA) at or below the mid-femoral head (below the inguinal ligament, above the bifurcation into superficial femoral and profunda). Fluoroscopic guidance targeting the femoral head reduces high punctures (retroperitoneal hemorrhage risk) and low punctures (pseudoaneurysm, AV fistula at the bifurcation).

TFA remains required for:

• Large-bore sheaths (8–24 Fr) for TAVR, Impella, ECMO cannulation, and some structural devices
• Complex peripheral vascular interventions
• Failed radial access with urgent need for large-catheter support
• Certain congenital or graft angiography requiring specific catheter curves from the aorta

Sheath sizes range from 5 Fr diagnostic to 14+ Fr for structural procedures. Manual compression or closure devices (Perclose, Mynx, Angio-Seal) achieve hemostasis post-procedure. Complications include retroperitoneal bleed (high puncture), pseudoaneurysm and AV fistula (low puncture), distal embolization, and infection.

The RCIS prepares the groin drape, assists with fluoroscopic landmarking, maintains sheath integrity, and monitors for groin hematoma expansion during and after the case.

Brachial Arterial Access

Brachial artery access at the antecubital fossa is a third-line arterial route used when radial and femoral access fail or when specific anatomy demands it (e.g., some LIMA angiography from the left arm). The brachial artery lies close to the median nerve and has limited collateral supply compared with the radial-ulnar arch.

Complication rates for limb ischemia, pseudoaneurysm, and nerve injury exceed radial access. Brachial sheaths are typically 5–6 Fr. Post-procedure compression requires firm, directed pressure at the puncture site without occluding collateral flow. RCIS candidates should recognize brachial access as a salvage option, not a routine alternative to radial.

Internal Jugular Venous Access

Internal jugular (IJ) venous access provides a central route for:

• Temporary transvenous pacing during bradyarrhythmias or high-grade AV block
• Pulmonary artery catheter (Swan-Ganz) placement for hemodynamic measurement
• Large-volume contrast or medication infusion when peripheral IVs are inadequate
• Emergency vascular access during cardiac arrest in the cath lab

The IJ vein runs lateral to the carotid artery beneath the sternocleidomastoid muscle, typically accessed at the apex of the triangle formed by the two heads of the SCM and the clavicle. Ultrasound guidance is standard of care to avoid carotid puncture and pneumothorax. Sheath sizes commonly range 6–9 Fr depending on the device (pacing wire vs. Swan).

RCIS responsibilities include preparing the central access tray, assisting with sterile ultrasound probe cover, flushing and connecting pressure transducers for hemodynamic monitoring, and securing lines to prevent air embolism during patient transfer.

Peripheral Venous Access

Peripheral IV placement (antecubital, hand, or forearm vein) is established before arterial access for:

• Iodinated contrast administration (with hydration protocol per institutional policy)
• Sedation and reversal agents (midazolam, fentanyl, flumazenil, naloxone)
• Emergency medications (epinephrine, atropine, amiodarone, fluids)
• Anticoagulation reversal agents when needed

At least one large-bore IV (18-gauge or larger) is recommended before procedures requiring rapid volume resuscitation. The RCIS verifies IV patency, confirms contrast allergy and premedication orders, and initiates hydration protocols for renal protection per provider orders.

Comparative Overview

Hemostasis and Post-Access Care

Each arterial site requires a site-specific hemostasis plan communicated before sheath removal. Radial patent hemostasis maintains antegrade flow while achieving hemostasis; femoral sites may use manual hold (15–20+ minutes) or suture-mediated closure. The RCIS monitors distal perfusion (pulse oximetry on the affected hand, dorsalis pedis or posterior tibial checks for femoral), compartment syndrome signs, and hematoma progression during recovery.

Exam Focus Points

High-yield RCIS scenarios include Barbeau Type D contraindicating radial access, identifying the common femoral artery puncture zone relative to the femoral head, recognizing when brachial access is a salvage route, and knowing IJ access supports temporary pacing. Comparison questions often test bleeding risk radial vs. femoral and sheath size limitations by site.