RailTracking: A Novel Technique to Overcome Difficult Anatomy During Transradial Approach

Abstract

Objective. We aim to investigate the safety and efficacy of a new technique, “RailTracking,” in the management of challenging transradial routes during percutaneous coronary interventions (PCI). Background. The transradial access (TRA) currently represents the access site of choice in PCI, but complex anatomy could lead to complications and access-site crossover. The assisted-tracking techniques described in the past (such as balloon-assisted tracking and pigtail-assisted tracking) are based on the concept of a “guiding tapered tip” to improve trackability. The RailTracking technique creates a tapered catheter tip using a dedicated device. Methods. We collected patient data from January 2021 to January 2022 in 2 high-volume centers using the RailTracking technique as a bail-out solution. A prospective analysis of the anatomical characteristics and outcomes of the study population was performed. Results. Seventy-seven patients were included in the study. All patients presented with challenging anatomies; 35.1% of the patients (n = 27) had small radial arteries, 19.5% (n = 15) had significant radial tortuosity, 2.6% (n = 2) had significant brachial tortuosity, 2.6% (n = 2) had subclavian tortuosity, and 1.29% (n = 1) had a critical subclavian lesion. In addition, 38.9% presented with severe radial spasm. The procedural success rate of the RailTracking technique was 98.7% (76/77 patients). The only case of failure presented with calcifications and a critical lesion in the subclavian artery. However, no periprocedural vascular complications occurred. This new technique appears safe, with a radial artery occlusion rate of 3.89% (n = 3) at 1-month follow-up. Conclusion. The new RailTracking technique improves catheter crossing in challenging anatomies and seems safe and effective in cases of failure with currently available approaches.

J INVASIVE CARDIOL 2022;34(11):E757-E762. Epub 2022 September 16.

Key words: balloon-assisted tracking, distal radial artery, percutaneous coronary intervention, proximal radial artery, Railway Sheathless, vascular access-site conversion

Transradial access (TRA) is recommended as the access site of choice by European Society of Cardiology guidelines and has become the most commonly used access in many centers.^1-3 TRA is increasingly preferred over transfemoral access site even for complex percutaneous coronary intervention (PCI) cases where the use of large 7-Fr guiding catheters is needed.^4-6 The pitfalls of TRA are mostly related to the small size of the radial artery, spasm, and presence of tortuosities at the level of the radial, brachial, and subclavian arteries.⁷ Despite the development of dedicated hydrophilic sheaths and catheters as well as the increased use of slender or assisted-tracking techniques, access-site crossover still ranges from 4.6% to 10%.^6,8-11 Sometimes the radial artery does not easily accommodate guide catheters, and tracking the course of the vasculature is difficult and could induce a severe spasm or a vascular complication. This complexity is more common when a large (≥7 Fr) guide catheter is needed or when distal radial access is preferred. The assumption of reducing the entry profile of the guide catheter by a telescopic maneuver has been validated previously using a balloon or another catheter (pigtail shape) positioned at the tip of the guide catheter.^9,10 As such, the gap between the wire and the guide catheter decreases and the transition zone is smoother, improving the trackability and crossing in challenging anatomies. Our new RailTracking technique (RTT) is based on the use of the 6-Fr and 7-Fr Railway Sheathless access system (Cordis Corporation) and has been recently introduced in our cath lab. The Railway Sheathless system offers the choice of 2 dilators compatible with .021˝ or .035˝ guidewires, fitting in any conventional 6-Fr or 7-Fr guide catheter. Once the device is prepared, the “dilator-within-guide” can be easily advanced through the conventional introducer or directly through the skin into the proximal or distal radial artery over the wire (Figure 1).¹² Our study aimed to assess the feasibility and safety of the RTT in routine clinical practice.

Methods

Patient population. Between January 2021 and January 2022, a total of 4210 transradial PCIs were performed at 2 high-volume centers by 6 operators. In 77 patients, complex anatomy and severe arterial spasm led to procedure interruption despite using the conventional methods and use of the RTT to overcome these problems, which are described in the next section.

Coronary procedure. For each procedure, we started by carefully positioning the hand before puncturing the proximal radial artery. Specifically, we settle the hand palm in a supine position to achieve hyperextension of the wrist. Then, a standard single anterior vessel wall puncture technique is performed without ultrasound guidance. We performed the puncture in the portion of the distal radial artery at the anatomical snuffbox (Figure 1A), in the dorsal side of the wrist (fovea radialis), limited posteriorly by the edge of the extensor pollicis longus tendon, and anteriorly by the extensor pollicis brevis and abductor pollicis longus tendons. Local anesthesia was performed using a mix of 3 mg of mepivacaine hydrochloride and 1 mg of isosorbide dinitrate injected subcutaneously. The access-site puncture was performed using a 21-gauge bare needle from lateral to medial with an angle of around 35°. After achieving radial artery access, a 5-Fr Radifocus sheath (Terumo) was inserted for the diagnostic angiogram or a 6-Fr sheath was inserted for coronary angioplasty. All patients received a low dose of midazolam, with additional intravenous morphine in case of discomfort. An intra-arterial spasmolytic cocktail with 2 mg of verapamil and 100 μg of nitroglycerin was administered routinely following sheath insertion. A second cocktail with verapamil and nitroglycerin was administered in case of pain during advancement of the catheters. All patients received unfractionated heparin at doses of 50 U/kg for diagnostic catheterization and 100 U/kg for coronary angioplasty. A conventional .035˝ J tip Emerald Wire (Cordis) was positioned in the ascending aorta. In case of difficulties in moving the guide catheter forward, the operator had different options, ie, downsizing the guide catheter, increasing patient sedation, further antispasmolytic mix, or using a balloon-tracking technique. The selection and use of one or more of the mentioned strategies depended on operator choice. In our strategy design, persistent failure prompted us to perform the RTT. At the end of the procedure, we used dedicated devices for achieving artery hemostasis through artery external compression for 2 hours: the TR Band (Terumo) for proximal radial artery and the Prelude Sync (Merit) for distal radial access site.

RailTracking technique description. After achieving access via the proximal or distal radial artery, the placement of a conventional 5-Fr sheath and a J tip .035˝ guidewire was positioned in the ascending aorta (Figure 1A, 1B). The RTT could then be performed as sheathless or not. The 5-Fr sheath was removed and a 6-Fr or 7-Fr guide catheter was preloaded on the .035˝-wire-compatible Railway dilator (Figure 1C, 1D). The system was advanced directly on the wire through the access in the aortic arch (Figure 1E) if a sheathless approach was needed. Alternatively, the RTT could also be performed by inserting the dilator and the guide catheter together through the sheath, leaving the 6-Fr introducer in place. The Railway dilator was pulled out when the guiding catheter reached the ascending aorta, followed by the guide catheter up to the coronary sinus for coronary cannulation. In our practice, when using a 7-Fr guiding catheter, distal RTT was preferred as the first choice in complex coronary. In other cases, the RTT was used more as a bailout strategy in case of complication while advancing the catheters.

Study endpoints. The primary endpoint of the study is procedural success with accomplishment of the PCI without access-site crossover. The secondary endpoints are access-site complications, including radial artery occlusion at 24-hour and 1-month follow-up, nonocclusive injury, hand ischemia, and cutaneous radial nerve damage.

Results

Baseline clinical and anatomical characteristics are shown in Table 1 and Table 2. Seventy-seven patients at 2 Belgian centers were included in the study from January 2021 to January 2022. The population had a mean age of 74 ± 9 years, 73 (94.80%) presented with hypertension, 20 (25.97%) had a history of diabetes mellitus, 69 (89.61%) presented with dyslipidemia, and 14 (18.18%) peripheral artery disease. Moreover, 8 patients (10.38%) presented with renal failure (estimated glomerular filtration rate <60 mL/min/m², stage ≥3), 11 patients (14.28%) had a history of previous PCI, and 3 patients (3.89%) had a history of coronary artery bypass graft surgery. Twenty-seven patients (35.06%) had a small radial artery (vessel diameter <1.5 mm), 15 patients (19.48%) had severe radial artery tortuosity, 2 patients (2.59%) had significant brachial tortuosity, and 2 patients (2.59%) had subclavian tortuosity. Thirty patients (38.9%) presented with severe resistant radial artery spasm and 1 patient (1.29%) had significant subclavian stenosis. 

PCI characteristics (Table 3). PCI access site was via the proximal right radial artery in 48 patients (62.33%), the proximal left radial artery in 11 patients (14.28%), and the distal radial artery in 18 patients (23.37%). Furthermore, 8 patients (10.38%) had a history of an endovascular procedure through the radial artery in the previous 6 months. A 7-Fr guiding catheter was used in 21 patients (27.27%) and a 6-Fr guiding catheter wa used in 56 patients (72.72%). Coronary diagnostic procedures represented 7 cases (9.09%) and PCIs were performed in 70 cases (90.90%). Multivessel PCIs were performed in 6 patients (7.79%). Finally, 7 patients (9.09%) were admitted for acute coronary syndrome.

Procedural characteristics and outcomes (Table 4). The procedural success rate was 100%, and the RTT was feasible in 76 cases (98.7%). In addition, only 1 patient (1.29%) required an access-site crossover to the left proximal radial artery due to uncrossable critical right subclavian stenosis. No periprocedural vascular complications occurred. Three patients (3.89%) presented with a proximal radial occlusion confirmed by echocardiographic Doppler examination. No other vascular complications were recorded at 1-month follow-up.

Discussion

Our study shows the safety and efficacy of the RTT, a new technique for challenging vascular anatomies. Furthermore, our strategy seems successful in our population when the standard methods using diagnostic or guide catheter fail in crossing radial, brachial, or subclavian artery complex anatomies. The standard methods are mainly based on down-sizing catheters, reducing the spasm, and increasing the vessel diameter by injecting a mixed solution of calcium blockers and nitrates.⁹ Other techniques rely on pressure-facilitated crossing, where an automated pump system injects saline solution through the introducer sheath, allowing radial artery navigation.¹³

In our population, the balloon-assisted tracking technique was notably used in 3 patients with significant brachial tortuosity who required a crossing attempt using a 7-Fr guiding catheter (Figure 2).⁹ These maneuvers are painful for the patients and time consuming for the operator. There are several pitfalls using the balloon-tracking technique, ie, the need to rewire the vessels with a coronary wire, the use of dedicated coronary devices in a peripheral vascular field, and potential vascular complications. The leading cause of failure in catheters crossing is the “razor” effect.^14,15 This complication is more critical in cases of spasm, tortuosity, small vessels, or large-bore (7-Fr) use.

To solve this issue, we recommend improving the coaxiality between the catheter tip and the vessel route and decreasing as much as possible the gap between the catheter tip and the wire (Figure 3). The Railway dilator is stiff enough to straighten tortuous anatomies and improve coaxiality, preserving good maneuverability. Moreover, the main advantage of this dedicated device is the tapered zone between the guidewire and the tip of the guide catheter, which determines a transition zone that reduces friction between the devices and vessel wall and eliminates the razor effect. Therefore, the RTT can be used in 2 ways, ie, with or without the introducer sheath. If we use the sheath, the guiding catheter with the dilator system facilitates an easy vascular crossing.

Another interesting consideration is the use of RTT in emergencies. In our cohort, almost 10% of patients presented with acute coronary syndromes. The technique’s feasibility guarantees a solution when the complexity of vascular navigation could compromise or delay the procedure achievement. Likewise, upsizing the catheter to 7 Fr using sheathless RTT covers a wide range of possible therapeutic scenarios, avoiding the detrimental aspect of femoral access. In accordance with the literature, in our experience, radial spasm is the most frequent cause of failure in endovascular upper-arm navigation, and the use of a sheathless approach seems to be an advantage to overcome this situation. Dedicated guide catheters (Eaucath; Asahi Intecc) can be used without an introducer sheath and represent an alternative; however, their shapes are limited.^16,17 Using the sheathless RTT, the guiding catheter is pushed ahead through the skin after retrieving the introducer. A considerable advantage is the suitability of the Railway dilator for use with all shapes, types, and sizes (6 Fr or 7 Fr) of guide catheters. The RTT can be used regardless of  proximal or distal radial access site and is easy to adopt in routine practice, showing good reproducibility among operators.

In our population, the standard methods mentioned above have a higher rate of failure compared with the literature. This result can be explained by the more extensive use of 7-Fr guiding catheters (27%) and the more frequent use of distal radial access (23%). The RTT reaches a 98.7% success rate, and we had only 1 patient requiring access-site crossover to a secondary vascular approach due to a severely calcified subclavian lesion. No vascular complications occurred during the procedure, even if patients in this study presented with complex anatomies and needed 6-Fr and 7-Fr guide catheters.

Conclusion

During TRA, a new technique called RailTracking—using a dedicated device to improve catheter navigation in complex upper-arm anatomies—seems safe and effective as a bailout strategy.

Affiliations and Disclosures

From the ¹Cardiovascular Department, Jolimont Hospital, La Louvière, Belgium; ²Department of Invasive Cardiology, Humanitas Clinical and Research Center, IRCCS, Rozzano, Italy; ³Cardiovascular Department, University Hospital CHU Marie-Curie, Charleroi, Belgium; and ⁴Cardiovascular Department, Clinique Saint Joseph, Vivalia, Arlon, Belgium. 

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Manuscript accepted April 13, 2022.

The authors report that patient consent was provided for publication of the images used herein.

Address for correspondence: Claudiu Ungureanu, MD, Jolimont Hospital, Rue Ferrer, 159, La Louvière, Belgium. Email: claudiu.ungureanu@jolimont.be

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