Lessons from Transulnar Access for Repeat Percutaneous Coronary Intervention After Radial Artery Occlusion
This case report and associated analysis explore the clinical implications of radial artery occlusion (RAO) following transradial percutaneous coronary intervention (PCI) and the feasibility of transulnar access as an alternative approach for repeat procedures. The findings highlight critical insights into the pathophysiology of RAO, procedural considerations for optimizing vascular access, and strategies to mitigate complications during coronary interventions.
Case Presentation
An 80-year-old male with a history of smoking and two prior PCIs via the right radial artery presented with substernal chest pain lasting 20 minutes. His initial PCI in February 2009 addressed an acute inferior wall myocardial infarction, followed by a second PCI six days later for elective stenting of the anterior descending coronary artery. Both prior interventions utilized 6F sheaths (11 cm length, Cordis Corporation). Following these procedures, the patient discontinued smoking. At the time of his third admission in August 2017, physical examination revealed a weak radial pulse but no symptoms of hand ischemia. An inverse Allen test demonstrated adequate collateral hand perfusion via the ulnar artery, with capillary refill within 6 seconds upon radial compression. Despite multiple attempts, radial artery puncture failed, prompting the use of transulnar access for cardiac catheterization.
The procedure involved successful implantation of two stents into the circumflex artery. Post-intervention forearm arteriography revealed an unexpected RAO proximal to the radial artery, distant from prior puncture sites. The occlusion was accompanied by robust collateral circulation from the ulnar and interosseous arteries, ensuring distal radial perfusion (Figure 1A–C).
Pathophysiology of Radial Artery Occlusion
The observed RAO in the proximal radial artery contradicts the conventional assumption that occlusions occur near puncture sites. Earlier Doppler ultrasound studies by the authors demonstrated that disrupted radial blood flow frequently localizes to the proximal or mid-artery rather than the access site. Optical coherence tomography (OCT) findings from related research further support this phenomenon. Yonetsu et al. identified intimal tears in the proximal radial artery, often adjacent to the sheath tip or near the radial ostium. These injuries likely result from mechanical trauma during catheter manipulation in unprotected arterial segments. Medial dissections in the proximal radial artery, caused by sheathless catheter advancement or withdrawal, exacerbate vascular damage.
The cumulative effect of repeated catheterization also contributes to endothelial dysfunction. Heiss et al. demonstrated that brachial artery impairment correlates with the frequency of catheter use, suggesting that vascular trauma extends beyond the radial artery. In this case, the patient’s two prior transradial procedures may have predisposed him to proximal RAO through chronic endothelial injury and hemodynamic stress.
Role of Collateral Circulation
Forearm arteriography in this patient illustrated compensatory collateral flow from the ulnar and interosseous arteries, circumventing the occluded radial segment. This finding underscores the importance of pre-procedural assessment of dual arterial supply. The inverse Allen test, though not definitive for predicting ischemic complications, provided preliminary reassurance about ulnar-dependent hand perfusion. However, the authors emphasize that collateral adequacy should not preclude efforts to minimize RAO risk, as asymptomatic occlusion may still limit future vascular access options.
Technical Considerations for Reducing RAO Risk
The authors propose several strategies to mitigate RAO:
- Proximal Radial Artery Puncture: Moving the puncture site proximally may reduce trauma to the unprotected radial segment. A prior study by Bi et al. found that longer sheaths (e.g., 11 cm) leave a shorter segment of the proximal radial artery unprotected during catheter manipulation, potentially lowering dissection and occlusion risks.
- Sheath Material and Design: Innovations in sheath composition and flexibility could minimize intimal injury. Current sheaths may contribute to proximal tears due to rigidity or friction during insertion.
- Limiting Catheter Exchanges: Reducing the number of catheters used during PCI may attenuate brachial and radial endothelial damage. Heiss et al. observed dose-dependent endothelial dysfunction correlated with catheter use frequency.
- Ultrasound-Guided Access: Real-time ultrasound visualization may improve puncture accuracy, particularly in patients with weak pulses or altered anatomy.
Clinical Implications of Transulnar Access
Transulnar access emerged as a viable alternative in this case, highlighting its utility when radial access is compromised. Lanspa et al. previously reported successful transulnar interventions in RAO patients, though proximal RAO localization was not emphasized. The authors argue that transulnar access should be considered earlier in patients with prior radial procedures, particularly when pre-procedural imaging suggests proximal radial vulnerability.
Limitations and Unanswered Questions
Ethical constraints prevent routine forearm arteriography in RAO patients, limiting the generalizability of observations. Additionally, the long-term patency of the ulnar artery after repeated access remains unclear. Further studies are needed to compare transulnar and transfemoral approaches in RAO patients, particularly regarding complication rates and procedural success.
Conclusion
This case underscores the complexity of RAO pathophysiology and the value of transulnar access in preserving vascular options for repeat PCI. Proximal radial artery injury, mediated by sheath-related trauma and catheter-induced endothelial dysfunction, represents a preventable complication. By adopting proximal puncture techniques, refining sheath technology, and prioritizing ulnar access in high-risk patients, clinicians can reduce RAO incidence and enhance procedural outcomes.
doi.org/10.1097/CM9.0000000000000737
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