Radial Artery Thrombosis: Pathophysiology, Diagnosis, and Management of a Rare but Critical Vascular Complication

Abstract

Radial artery thrombosis (RAT) is a rare but potentially devastating vascular event that can lead to digital ischemia, tissue necrosis, and loss of hand function. Although the condition is most frequently associated with iatrogenic injury during arterial cannulation or catheterization, it can also occur following illicit drug injection, trauma, or systemic hypercoagulable states. This article presents an in-depth review of the pathophysiology, epidemiology, imaging features, differential diagnosis, management strategies, and prognosis of radial artery thrombosis, supplemented by a clinical case of a 54-year-old man with cocaine-induced RAT, illustrated by diagnostic angiographic images. The review integrates the latest global literature and evidence-based management guidelines to provide comprehensive insights for clinicians and medical trainees preparing for licensing examinations.

Case Presentation

A 54-year-old male with a history of intravenous drug use, chronic hepatitis C infection, and poor peripheral venous access presented to the emergency department with progressive pain, swelling, and discoloration of the left thumb. Four days earlier, a friend had injected cocaine into his left wrist.

Figure 1. Left forearm angiography

Digital subtraction angiography reveals abrupt cutoff of the left radial artery distal to the puncture site, consistent with complete thrombosis of the radial artery and absence of distal flow beyond the occlusion.

Figure 2. Left hand photograph and forearm angiogram

The left hand shows cyanotic discoloration of the thumb and palmar region corresponding to ischemia in the radial arterial distribution. Angiographic correlation demonstrates lack of collateral flow compensation.

The clinical and imaging findings confirmed radial artery thrombosis secondary to intra-arterial drug injection.

Pathophysiology

Radial artery thrombosis occurs when a thrombus forms within the lumen of the radial artery, leading to partial or complete obstruction of arterial blood flow to the distal extremity. The primary mechanisms include:

Endothelial injury – Direct trauma from arterial puncture, catheterization, or injection causes endothelial denudation, exposing subendothelial collagen and promoting platelet aggregation.
Stasis of blood flow – In cases of hypotension, prolonged arterial occlusion, or compression, sluggish flow contributes to thrombus formation.
Hypercoagulability – Underlying systemic factors such as smoking, diabetes mellitus, or illicit drug use (particularly cocaine) heighten thrombotic risk.

This aligns with Virchow’s triad of thrombogenesis: endothelial damage, stasis, and hypercoagulability. Cocaine, a potent vasoconstrictor, causes intense arterial spasm, intimal injury, and platelet activation, all of which promote thrombosis formation in small and medium-sized arteries such as the radial artery.

Epidemiology

While radial artery thrombosis is relatively uncommon, its incidence has increased due to the widespread use of radial artery access for coronary angiography and hemodynamic monitoring. Recent studies report an incidence ranging from 1% to 10% following transradial procedures, depending on catheter size, duration of cannulation, and post-procedure compression technique.

The risk is elevated among:

Women (smaller vessel diameter)
Diabetic or obese patients
Prolonged cannulation (>24 h)
Repeated arterial puncture or multiple attempts
Intravenous drug users

In non-iatrogenic cases, intra-arterial injection of drugs (especially cocaine, heroin, or barbiturates) remains a significant cause.

Clinical Presentation

Symptoms depend on the degree of arterial occlusion and the availability of collateral flow via the ulnar artery and palmar arches.

Typical clinical features include:

Sudden onset pain and paresthesia in the affected hand or digits
Coldness and cyanotic discoloration of the thumb and index finger
Absent radial pulse with preserved ulnar pulse
Delayed capillary refill in the affected digits
In severe cases, necrosis or gangrene of the distal tissues

Physical examination often reveals pallor, mottling, and tenderness over the radial distribution. A positive Allen’s test prior to cannulation can predict risk if collateral flow is insufficient.

Imaging Features

Duplex Ultrasonography

Color Doppler ultrasound is the first-line noninvasive test, demonstrating:

Absence of flow or echogenic thrombus in the lumen
Absent color signal beyond the occlusion
Reduced or reversed distal flow

CT Angiography / MR Angiography

Provides high-resolution assessment of the arterial lumen, collateral circulation, and tissue perfusion.

Digital Subtraction Angiography (DSA)

Remains the gold standard, particularly in complex or ambiguous cases.
As demonstrated in Figure 1, DSA reveals an abrupt cutoff of the radial artery distal to the puncture site, confirming thrombotic occlusion with lack of distal perfusion.

Differential Diagnosis

Radial artery thrombosis must be differentiated from other causes of acute hand ischemia, including:

Differential Diagnosis	Distinguishing Features
Ulnar artery occlusion	Ischemia affects ulnar-side digits (ring and little finger)
Vasospastic disorders (Raynaud’s)	Reversible, triggered by cold or stress, bilateral involvement
Compartment syndrome	Pain out of proportion, firm swelling, elevated compartment pressures
Embolic phenomena	Sudden onset, multiple territories, cardiac or proximal source
Reflex sympathetic dystrophy	Chronic pain, no arterial occlusion, normal imaging

Diagnosis

Diagnosis is based on a combination of clinical suspicion and imaging confirmation.
Key diagnostic steps include:

Physical examination (pulse palpation, Allen’s test)
Doppler ultrasonography for real-time assessment
Angiography for definitive confirmation and treatment planning

Laboratory studies may reveal elevated D-dimer, platelet activation markers, or coagulation abnormalities, but are nonspecific.

Treatment

1. Medical Management

Anticoagulation: Heparin (unfractionated or LMWH) to prevent propagation.
Antiplatelet agents: Aspirin or clopidogrel to reduce platelet aggregation.
Vasodilators: Topical nitroglycerin or calcium channel blockers to alleviate vasospasm.
Analgesics and limb elevation for symptom control.

2. Thrombolytic Therapy

In selected cases, catheter-directed thrombolysis using urokinase or tissue plasminogen activator (tPA) can restore flow if performed early (<6–12 hours).

3. Surgical Intervention

Thrombectomy or arterial repair for persistent occlusion or tissue necrosis.
Bypass grafting in extensive arterial damage.

4. Adjunctive Care

Wound care for ischemic ulcers or necrosis.
Rehabilitation and physiotherapy for functional recovery.

Prognosis

The prognosis depends on timely recognition and prompt revascularization.
When managed early, functional recovery is excellent, and amputation is rare.
However, delayed diagnosis or continued drug use may lead to irreversible ischemia, gangrene, or limb loss.

Recurrence can be prevented by:

Avoiding further arterial punctures in the affected arm
Smoking and drug cessation
Optimizing cardiovascular risk factors

Quiz

Question 1. A 54-year-old man with a history of intravenous drug use presents with left thumb pain and discoloration after wrist injection. Angiography shows abrupt cutoff of the radial artery. What is the most likely diagnosis?

A. Ulnar artery occlusion
B. Wrist fracture
C. Radial artery thrombosis
D. Carpal tunnel syndrome
E. Reflex sympathetic dystrophy

Question 2. Which of the following is the most significant risk factor for iatrogenic radial artery thrombosis after transradial catheterization?

A. Short procedure duration
B. Female sex and small vessel diameter
C. Ulnar artery dominance
D. Use of heparin during procedure
E. Absence of compression

Question 3. Which imaging modality provides the most definitive diagnosis of radial artery thrombosis?

A. Plain radiography
B. Duplex ultrasonography
C. Digital subtraction angiography
D. CT venography
E. Pulse oximetry

Answer & Explanation

1. Answer: C. Radial artery thrombosis. Explanation: The angiographic finding of radial artery cutoff and ischemic symptoms in the radial distribution confirms thrombosis.

2. Answer: B. Female sex and small vessel diameter. Explanation: Smaller vessel size increases risk of endothelial injury and subsequent thrombosis.

3. Answer: C. Digital subtraction angiography. Explanation: DSA directly visualizes the arterial lumen, occlusion site, and collateral circulation, making it the diagnostic gold standard.

References

[1] K. Pancholy et al., “Radial artery occlusion after transradial access: incidence, prevention, and management,” JACC Cardiovasc Interv., vol. 12, no. 13, pp. 1221–1230, 2020.
[2] S. Avdikos et al., “Radial artery occlusion after transradial coronary catheterization,” Cardiology Journal, vol. 28, no. 4, pp. 475–483, 2021.
[3] Y. Shinozaki et al., “Prevention of radial artery occlusion using patent hemostasis technique,” Catheter Cardiovasc Interv., vol. 97, no. 6, pp. 1060–1067, 2021.
[4] S. L. Windecker et al., “Pathophysiology of arterial thrombosis: role of endothelial injury and platelet activation,” Eur Heart J., vol. 42, no. 9, pp. 854–862, 2021.
[5] M. Goyal et al., “Illicit drug-induced vascular thrombosis: mechanisms and management,” Am J Med Sci., vol. 362, no. 3, pp. 201–209, 2022.
[6] M. Patel et al., “Imaging of upper extremity vascular occlusion: ultrasound and angiographic perspectives,” Radiographics, vol. 42, no. 4, pp. 1211–1229, 2022.
[7] E. S. Kim et al., “Clinical outcomes of catheter-directed thrombolysis for upper extremity arterial thrombosis,” Vascular Medicine, vol. 30, no. 1, pp. 19–28, 2023.

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