Access-Site Complications of the Transfemoral Approach

The radial access route has significantly lower complications compared to the femoral access route. Often users have become used to the femoral approach and its attendant complications but it is worth reviewing that despite its minimally invasive nature as opposed to open craniotomy, endovascular transfemoral access is certainly not without risk. These risks include life threatening retroperiotenal hematoma formation and local hematoma formation as well as limb threatening occlusion of the femoral artery, which is an end artery thus must be urgently revascularlized in the event of compromise. The complications of femoral access are reviewed as well as strategies for management.

Transradial Interventional Procedures

The majority of neurointerventions can be performed via the radial approach, even with the femoral catheters. The specific case set-up depends on the goals of the intervention. If using the femoral catheters, one is limited to the 6F and 8F systems. The former offers the protection of a radial sheath, the latter must be performed sheathlessly. The size of the radial artery and difficulty and support demands of the case dictate the preferred setup. With minimal experience, once diagnostic angiography is mastered, interventions can easily be learned. The technical pearls and nuances of performing complex neurointervention via the radial approach are reviewed.

Use of Long Radial Sheaths for Radial Artery Spasm in Neurointerventions

One of the challenges of the radial approach is radial artery spasm. Because of the smaller caliber, the guide catheters can cause significant spasm that can complicate the procedure or even preclude it. One of the most effective ways to avoid radial artery spasm and stuck catheters is to employ the use of a protective sheath. Recently special long radial sheaths have been developed that completely cover the radial artery, thus precluding the possibility of spasm. In addition, the protection results in less trauma to the innovation of long radial sheaths has dramatically decreased the issues surrounding radial artery spasm. The nuances of the long radial sheaths and a protocol for their use are described.

Future Directions

The transradial approach (TRA) reduces mortality, morbidity, access-site complications, hospital cost, and length of stay while maximizing patient satisfaction. The overall lag between the introduction of the transradial approach and its widespread use within the neurointerventional niche is due to a variety of factors, including perceived difficulties in navigation, lack of exposure during training, and complexity of the neurointerventional procedures. With more training programs converting to TRA, a new generation of fellows will be trained in the technique; in addition to that, a lot of work is on the way to develop new catheters dedicated for TRA.

Closure Techniques

The superficial location of the radial artery access site eliminates the need for overly specialized closure devices. Manual compression is considered the gold standard technique. Closure devices in their many iterations are designed to work by applying continuous pressure using an adjustable balloon. They are arguably superior to manual compression as they exert a continuous and gentle pressure on the artery. The simplest, and cheapest devices might be the best ones. A good closure technique ensures compression with a “just needed” intensity to maintain anterograde flow. A good technique also incorporates the principle of patent hemostasis with or without prophylactic ulnar artery occlusion while keeping the whole process relatively simple. These techniques result in fewer radial artery occlusions and other complications. Lower complications ensure patency of the radial artery for future procedures.

Intraoperative Transradial Angiogram

Intraoperative angiogram (IOA) is a valuable tool for cerebrovascular surgery. It confirms surgical outcomes for a variety of pathologies. It allows early identification of any residue or compromise of a parent vessel. This chapter will delve into the advantages, limitations, and technical nuances of IOA via a radial approach. IOA is a valuable tool for cerebrovascular surgery. IOA allows early diagnosis and identification of any residue and obviates the need for postoperative diagnostic angiogram. It confirms surgical outcomes for a variety of pathologies such as aneurysm occlusion and parent vessel patency, arteriovenous malformation resection, dural fistula ligation, bypass patency, and adequate carotid revascularization after endarterectomy. Though there are alternatives, such as indocyanine green fluorescence (ICGA) angiography, formal angiography remains the gold standard as it overcomes the limitations of ICGA. Femoral access has been the main approach for IOA with an excellent safety profile. Recently the radial approach has been gaining wide interest among neurointerventionalists, and there are several advantages for the radial approach over the femoral approach in IOA.

Left Transradial Approach

The left transradial access has an essential role in the cerebrovascular armamentarium in limited indications. Access to the posterior circulation via the left vertebral artery is one of the main indications, in addition to cases that require bilateral access. It has several advantages such as using the non-dominant hand, ergonomic when accessing through the anatomical snuffbox, and overcomes certain anatomical variations. This chapter will delve the advantages, limitations, and technical nuances of the left transradial approach.

Pediatric Transradial Approach

Neuroendovascular surgery has become an indispensable domain in the treatment of cerebrovascular disease with a slew of treatment options for numerous pathologies. The field experienced a movement toward a transradial approach for diagnostic and interventional procedures. Advantages of the transradial approach include lower risk for complications, which can be fatal using the transfemoral route, higher patient satisfaction, and shorter hospital stays. Those advantages are not unique to the adult population but are, in fact, even more pronounced in pediatrics. They include early mobilization of patients since flat bed rest is not required as it is with transfemoral puncture for hemostasis at the groin. This also obviates the need for continuous intravenous sedatives, which is fraught with its own risks. Early reports have demonstrated the feasibility of transradial cerebral angiography in children. Others have also shown that the transradial approach can be safely used to administer intra-arterial chemotherapy in children with retinoblastoma. A standardized protocol is imperative to maximize the success rate of the transradial approach in pediatrics and includes the routine use of ultrasound as well as a “radial cocktail” to avoid vasospasm. While transfemoral may be the conventional route, transradial offers a plethora of advantages, particularly in children. As more experience in transradial is gained in adults, it is likely that this will translate into more transradial procedures in children as well.

Transradial Approach for Stroke

Performing a mechanical thrombectomy via the radial approach is a critical skill to be learned in the armamentarium of the neurointerventionalist. In addition to potential safety advantages, patient anatomy often renders femoral access to the internal carotid artery impossible. Morbid obesity, severe aortic arch tortuosity, or aortofemoral occlusive disease can cause significant delays in accessing the target vessel or even complete failure. There are unique challenges to performing mechanical thrombectomy via the radial approach, given the need for speed and qualified metrics of technical success. The technical nuances and pearls of performing a mechanical thrombectomy via the radial approach are reviewed.

The Rationale for Radial Artery Access in Neurointerventional Surgery

Over 20 years of investigation and experience have gone into pioneering the radial approach for cardiac interventions. This has shown the technique to be superior to the traditional transfemoral technique for a variety of reasons. Neurointerventionalists have until recently been unaware of this innovation and are only starting to use it in their practice. Most of the data from the interventional cardiology journey into radial access is unknown to the neurointerventionalist audience, and concepts that underpin radial access are unfamailiar. Even basic concepts such as radial arterial anatomy, collateral circulation of the hand, and low rates of ischemic complications have been siloed in the cardiology literature. The core rationale for the transradial approach is reviewed.