Ignoring the Proverbial Elephant: Unmeasured, Underreported, and Unpublished Radial Artery Access Complications

Endovascular surgery is an innovative and evolving specialty with safe arterial access being a cornerstone. The continuous integration of new technology affords proceduralists the opportunity to expand the armamentarium of treatment strategies for a wide scope of vascular pathologies. Endovascular surgery's versatility is, in many ways, made possible through the ability to obtain arterial access in various locations (radial, brachial, axillary, carotid, femoral, popliteal, tibiopedal arteries, etc). Radial artery access is described, in this persuasive American Heart Association Scientific Statement, as transformative, compelling, promising, and exciting. So, it may go without saying that if femoral artery access was the preferred arterial access workhorse site of ‘yesterday', then radial artery access is quickly becoming an access site choice of ‘today'. But what will happen tomorrow?

The Good

Peripheral vascular interventions (PVIs) for intermittent claudication and chronic limb threatening ischemia are increasing over time,^1,2 particularly in outpatient and office-based settings.^3,4 Alongside these practice setting and volume changes have come an expansion in the availability of lower profile devices, drug-coated and specialty balloons, atherectomy, lithotripsy, mechanical thrombectomy and re-entry devices, stents and scaffolds, to name a few. Radial artery access is the preferred approach for coronary interventions, with a nearly 3-fold increase in its use over time tom most recently, being used in 70% of PCIs captured in the National Cardiovascular Registry's CathPCI Registry.⁵ This Scientific Statement encourages implementation of routine radial artery access for PVI given acclaimed successes for coronary intervention, and mostly posits that radial artery access holds the benefit of shorter post-procedure activity restrictions and length of stay, reduced radiation exposure and healthcare costs, and a decreased complication rate as compared to femoral artery access. However, just as tibiopedal access has not become the preferred access site for lower extremity PVI cases in most vascular practices, neither has radial artery access. Nor should it.

The Bad

It is a fact that the frequency of use of radial artery access has been increasing and its application for PVI will continue to grow. At this time, the burden of peripheral artery disease necessitating endovascular intervention outpaces the availability of low-profile, ‘extra-long' length devices, and therefore, equipment availability limits our ability to apply radial artery access liberally to all comers. This is a reality that will not change until the necessity, safety, and demand is well communicated and designed in collaboration with our industry partners.

There was mention within the Scientific Statement that the feasibility of radial artery access should be included in the PVI ‘time-out' performed just prior to access is obtained, however, this question should be asked and answered before the patient enters the interventional suite. Using the coronary-based literature, there is an obvious appreciation for the radial artery access learning curve,⁶ though complication rates are low with appropriate testing and duplex assessment of the upper extremity vasculature.^7,8 However, robust access site comparisons are absent largely due to the lack of literature that addresses maintenance of access patency and complication severity or rate after radial artery access. There is a clear need to define what appropriate and cost-effective risk stratification for hand ischemia prior to radial artery access looks like. There also remains a need to define absolute and relative contraindications to radial artery access. Given the variability in practice, characterizing and adjudicating methods that are employed to maintain patency of the radial artery during the procedure would be helpful.

The Ugly

Radial artery access complications are unmeasured, underreported, and unpublished, but certainly do exist. The available literature, as summarized in this Scientific Statement, suggests that radial artery complications are infrequent. However, a substantial proportion of the literature that informs this conclusion is based on in-hospital or early-term follow-up.^9,10 Complications can include ischemic (e.g. dissection, thrombosis, distal embolization) and non-ischemic complications (e.g. hematomas, pseudoaneurysms, arteriovenous fistula, nerve injury, compartment syndrome), and are not often recognized in the recovery room. In fact, reports suggest that radial artery access complications occur at a median of 1 day after discharge from an elective PVI.¹¹ It is possible that radial artery access complications are not well captured given delayed presentation and subsequent ascertainment bias, and/or underdiagnosis given asymptomatic disease in well collateralized patients. For example, a pseudoaneurysm may be asymptomatic early on, however, once it grows, it can lead to chronic distal embolization or compressive nerve palsies and present weeks to months following the index procedure. While going home after a few hours of recovery in the postprocedural unit is desired by all invested parties, patients should be educated as to what is normal, what is abnormal, and what is concerning after a procedure that uses radial artery access. They also need a specialist to evaluate them in the event that something is, or may be, wrong. Another important point that was not considered in the Scientific Statement is that the ability to rescue patients with acute, limb threatening radial artery complication requires specific local technical expertise while the management of symptomatic or chronic limb threatening complications found later requires referral to specialty providers. While a reported majority of radial access site complications do not require operative management,¹² when open surgery is deemed necessary, Vascular Surgery, Orthopedic Surgery and/or Plastic and Reconstructive Surgery expertise may be needed, however, may not be readily available at facilities across the country particularly given current and predicted workforce shortages in both urban and rural areas.¹³ Further, though not captured as a complication, conversion from radial artery to alternative access is 7-11% in published studies.⁷ While we would hardly consider this a failure of radial artery access, it drives home the point that radial artery access should not be considered the primary access site for PVI, but rather an acceptable option in certain patients.

Conclusion

While the Scientific Statement's title and abstract suggest a focus on PVI, arguments for routine radial artery access are bolstered with its more obvious and appropriate applications given the available resources in renal and visceral artery interventions or high grade blunt traumatic solid organ injury or pelvic fractures. Other routine and less conspicuous applications that were not covered in this Scientific Statement include management of type II endoleak after endovascular aortic aneurysm exclusion, embolization for visceral artery aneurysms when appropriate, diagnostic and therapeutic interventions for celiac artery compression syndrome after median arcuate ligament release, or the endovascular management of uterine fibroids in women, for example. The authors ultimately conclude that radial artery access is unlikely to become the preferred access approach for PVI, which is appropriate. At present, endovascular devices are limited by size and length and for radial artery access to become commonplace for all or even most PVI, this would mean that radial arteries would have to be able to accommodate devices that can facilitate aggressive limb salvage techniques such as deep vein arterialization or pedal loop reconstruction, of which, at present, is just not possible.

Radial artery access is a necessary skill within the armamentarium of proceduralists who manage PVI patients and should be utilized in select patients with favorable anatomy that allows for safe, efficient, and efficacious PVI interventions. There are some critical issues within the field of ‘alternative access sites.' This field needs guidance on which patients are best suited for radial artery access and how to determine this in an efficient and cost-effective manner in standard clinical settings, how can the PVI proceduralist maintain patency during the procedure that utilizes radial artery access, characterization and reporting of the true event rate and severity of early, midterm, and longitudinal complications after radial artery access, and ensure there is appropriate referral in the setting of need for time sensitive, semi-elective, or long-term complication management after radial artery access. Recommendations synthesizing studies that clearly address these knowledge gaps for the proceduralist who either uses or desires to use radial artery access in their practice are the recommendations that the PVI field needs. While we too are part of the increase in use of radial artery access as we frequently use it in our own noncoronary practices, we cannot ignore radial artery access complications simply because we believe them to be rare based on insufficient data.