Early Clinical Experience With CrossFAST, a Novel, Microcatheter-Led Delivery System for Complex Percutaneous Coronary Intervention

Abstract

Background

Guide extension catheters are integral to coronary intervention. First-generation guide catheter extension devices are monorail, blunt-ended tubular structures with limitations. CrossFAST (Vantis Vascular) is a next-generation, microcatheter-led advanced device delivery system intended to allow safe, deep coronary intubation to assist in complex percutaneous coronary intervention.

Methods

The CrossFAST device delivery system was FDA 510(k) cleared in December 2024. We describe this new technology and review 4 of the early clinical cases utilizing CrossFAST to assist in complex percutaneous coronary intervention.

Results

The CrossFAST system was used successfully to assist in-stent delivery in all 4 of these cases: Distal right coronary artery, proximal plus mid left circumflex, mid left anterior descending, and proximal diagonal. The device crossed the target lesion in all cases, allowing seamless stent delivery without complications after conventional attempts, including guide extension catheters, had failed.

Conclusions

The CrossFAST was used successfully in the treatment of these 4 complex, calcific, coronary artery disease cases, to assist in coronary device delivery and placement. Additional data will be needed to further evaluate the safety and efficacy of this technology as compared to conventional approaches to complex coronary artery disease.

Introduction

Guide extension catheters (GEC) have become an important tool to provide extra support and assist in device delivery in percutaneous coronary intervention (PCI).¹ GEC are used for additional support and “pushability” when guide catheter support is insufficient, which is increasingly common in the era of radial interventions. GEC can also be used for deep coronary intubation, which is a valuable maneuver but carries a risk of coronary dissection and is not always successful.^2,3

The CrossFAST (Vantis Vascular) is a next-generation device delivery system developed to overcome some of the challenges and risks associated with deep GEC intubation (Central Illustration).⁴ It includes a monorail inner microcatheter that is “snapped” into the outer catheter with a seamless transition to provide a flexible, low-profile leading tip to facilitate safe, rapid delivery of the extension catheter to the mid or distal vessel.

Central Illustration.

The CrossFAST system vs a conventional guide extension catheter. (A) The GuideZilla guide extension catheter placed over a 0.014-inch coronary guide wire. One can appreciate the sharp edge of the distal, blunt-ended tube (black arrow). (B) The CrossFAST system over a 0.014-inch guide wire, illustrating the seamless transition between the outer catheter and the inner catheter (black arrow) and the very small (0.018-inch) distal tip of the inner microcatheter as a transition to the coronary guide wire (orange arrow.) (C) A similar illustration with the 2 catheters side-by-side, showing the blunt-ended tip of the GuideZilla compared to the seamless edges and leading microcatheter tip (black arrow and orange arrow) of the CrossFAST.

We report 4 cases of complex PCI utilizing the CrossFAST system for stent delivery after failure using conventional methods and available equipment. All 4 cases resulted in successful stenting without complications.

Methods

The CrossFAST device delivery system was FDA 510(k) cleared in December 2024. The development of the CrossFAST device has been described previously.⁴ This paper describes this new technology and reviews 4 of the early clinical cases done utilizing CrossFAST to assist in complex PCI. We retrospectively identified 4 patients who underwent successful complex PCI utilizing the CrossFAST device. Demographic data were collected, including age, sex, prior medical history, and presenting symptoms. Angiographic images and procedural data were reviewed. Procedural success was defined as no residual stenosis with TIMI 3 flow in the target vessel. Charts were reviewed for complications, including myocardial infarction, target vessel revascularization, and bleeding. All data were deidentified and collected in accordance with the appropriate ethical guidelines. As the case series involved only a review of anonymized clinical data, institutional review board approval and individual patient consent were not required.

Case studies

Case 1

A 63-year-old man was admitted with unstable angina. He had a known history of coronary artery disease (CAD) and prior coronary artery bypass grafts (CABG), including left internal mammary artery (LIMA) to left anterior descending (LAD), saphenous vein graft to obtuse marginal (OM), and right posterior descending artery (PDA) sequential graft. Diagnostic coronary angiography demonstrated a patent LIMA to LAD graft, an occluded vein graft, and a dominant right coronary artery (RCA) with a long segment of calcified, angiographically moderate stenosis of the proximal to distal RCA into the proximal PDA (Figure 1A, B). There was severe stenosis of the LAD proximal to the graft, and mild stenosis of the left circumflex (LCX) and OM arteries. A Judkins Right 4 (JR4) guide was used to engage the RCA. Adenosine fractional flow reserve was 0.63, indicating severe stenosis. A SION blue wire (ASAHI INTECC) was advanced into the distal RCA and exchanged for a Wiggle wire (Abbott) using a microcatheter. The vessel was predilated to 2.0 mm, and intravascular ultrasound (IVUS) demonstrated mixed fibrocalcific plaque in the mid to distal RCA and fibrofatty plaque of the proximal right PDA. Based on angiography, fractional flow reserve, and IVUS, we elected to stent from the proximal to distal RCA into the proximal PDA. The vessel was then thoroughly predilated with noncompliant balloons, including up to 3.0 mm in the mid-RCA, but because of significant tortuosity, a 2.75 × 38 mm Onyx Frontier stent (Medtronic) could not be delivered beyond the mid to distal RCA into the PDA. A 5.5F CrossFAST delivery system (Figure 1) was then advanced over the wire into the distal RCA without resistance (Figure 1C). The inner catheter was removed, the stent was delivered into the target area from the distal RCA into PDA, and the catheter was pulled back to allow for coronary flow. The stent was positioned and deployed with excellent results. The inner CrossFAST catheter was reinserted, and the CrossFAST system was readvanced into the distal RCA without issue. Overlapping 3.5 × 38 mm and 3.5 × 18 mm Onyx stents were placed from distal to proximal, and final angiography demonstrated excellent results with TIMI 3 flow and no significant residual stenosis (Figure 1D). The patient was discharged the following day without complications.

Figure 1.

Case 1. Coronary angiography of the tortuous, dominant right coronary artery (RCA) in left anterior oblique (A) and cranial (B) projections, demonstrating diffuse, calcified, angiographically moderate stenosis of the proximal to distal RCA into the proximal posterior descending artery, with positive adenosine fractional flow reserve of 0.63. The CrossFAST catheter was advanced to the distal RCA to aid in the delivery of stents (C), with excellent final result (D).

Case 2

A 76-year-old man with hypertension, type II diabetes mellitus, and chronic kidney disease, was admitted to the intensive care unit with critical limb ischemia. He underwent left femoral-tibial bypass, which was complicated by early graft thrombosis, and subsequently underwent graft revision 1 week later. Postoperatively, he developed refractory chest pain and new onset troponin elevation consistent with high-risk non–ST elevation acute coronary syndrome and was referred for urgent catheterization. He further developed worsening hypoxic respiratory failure, thought to be due to heart failure, and was intubated prior to the procedure. Low contrast coronary angiography revealed severe 3-vessel CAD, including severe ostial to distal LCX stenosis, with subtotal occlusion of the distal LCX into OM2, severe proximal to mid-LAD stenosis, and severe mid to distal RCA into proximal right PDA stenosis (Figure 2A). We conferred with the referring cardiologist and rapidly consulted the cardiac surgeon, but his condition was deemed too unstable for surgery. Thus, we elected to treat the culprit LCX with minimal contrast. An XB 3.0 guide catheter was used (Cordis). The lesion could not be crossed with a SION blue wire because of severe calcification and tortuosity; a Pilot 50 wire (Abbott) was used to cross into the distal OM2. The wire was then exchanged for a Wiggle wire using a microcatheter. The LCX was predilated to 2.25 mm, and IVUS was performed, revealing diffuse, heavily calcified plaque with severe stenosis. A SION blue wire was advanced into the atrioventricular groove LCX, and gentle predilation of the ostial vessel was performed using a 2.0 mm balloon to avoid jailing during stenting of the OM. The LCX was further dilated to 3.25 mm proximally and 2.5 mm distally, but a 3.0 × 38 mm Onyx stent could not be delivered beyond the proximal LCX because of calcification and the angulated takeoff of the LCX. The side branch wire was removed, and a 5.5F CrossFAST delivery system was then advanced over the wire into the distal LCX without resistance (Figure 2B). The inner catheter was removed, the stent was delivered into the target area from the proximal to distal LCX, and the catheter was pulled back to allow for coronary flow. The stent was positioned and deployed with excellent results. The inner CrossFAST catheter was reinserted, and the CrossFAST system was readvanced into the mid-LCX without issue. An overlapping 2.25 × 38 mm Onyx stent was placed from the distal LCX into OM2. The stents were postdilated to 2.5 mm distally and 3.25 mm proximally, and final angiography demonstrated excellent results with TIMI 3 flow and no significant residual stenosis (Figure 2C). The patient tolerated the procedure well and was transferred back to the intensive care unit in stable condition with improved chest pain.

Figure 2.

Case 2. Coronary angiography of the left circumflex artery (LCX) demonstrating an angulated takeoff from the left main coronary artery with diffuse, heavily calcified, severe stenosis of the proximal to distal LCX, with a subtotal occlusion of the distal LCX into the large second obtuse marginal (OM2) (A). The CrossFAST catheter was advanced to the distal LCX to aid in the delivery of stents (B), with excellent final result (C).

Case 3

An 83-year-old woman presented with progressive exertional chest discomfort and dyspnea on exertion consistent with acute coronary syndrome/unstable angina. Diagnostic left catheterization demonstrated moderate disease in the dominant RCA and mild disease in the LCX. There was diffuse coronary calcification, with severe calcification in a high-grade mid-LAD lesion involving a bifurcation with a medium-sized diagonal that also had a high-grade ostial lesion (Figure 3A). The mid-LAD lesion was extremely torturous with a 45° bend, followed by an 85° bend through the calcified segment. There was also a distal 80% narrowing with calcification. An XB 3.5 guide catheter was used. The diagonal and the LAD crossed with Runthrough wires. Balloon predilation was performed of the mid-LAD, distal LAD, and the diagonal. At this point, a coronary stent could not be delivered and was stopped abruptly at the first bend in the LAD. A Telescope GEC was advanced, but was also stopped in the mid-LAD, significantly proximal to the lesion, and the stent could not be delivered. A 5.5 French CrossFAST delivery system was advanced through the mid-LAD lesion with the outer catheter delivered well past the mid-LAD (Figure 3B) with no resistance. The inner catheter was removed, and the distal lesion was stented with a 2.25 × 23 mm XIENCE stent (Abbott), followed by stenting of the mid-LAD with a 2.75 × 23 mm stent at 18 atm. Postdilation was performed, yielding a very good result with good TIMI 3 flow in the diagonal branch (Figure 3C). The patient tolerated the procedure well and was discharged without complications the same day.

Figure 3.

Case 3. (A) A severe, heavily calcified mid-LAD lesion with tortuosity and ostial disease involving the origin of the diagonal. White arrows point out the areas of severe obstruction in the mid-LAD. The center panel (B) shows the distal delivery of the CrossFAST system with the proximal black arrow, pointing out the marker on the outer catheter, and the more distal black arrow pointing out the tip of the CrossFAST inner microcatheter. One can note that the outer catheter, which is functionally like a guide extension tube, has been tracked distal to the mid-LAD lesion. After a stent delivery through the Cross CrossFAST and postdilation, the final image (C) shows a very good final result, with minimal residual stenosis, and with preservation of flow into the diagonal branch, as noted by the white arrows.

Case 4

A 70-year-old morbidly obese man with a history of 2-vessel CABG in 2008 presented with ongoing exertional angina. He had recently undergone PCI to the LIMA anastomosis with the mid-LAD. At that time, he was noted to have a high-grade, calcified, and modestly angulated lesion at the proximal edge of a previously placed stent (2019) in a large first diagonal artery (Figure 4A). He returned for an intervention of that vessel. The procedure was performed from a left radial approach using a 6F XB 3.5 guide catheter; a 0.014-inch Runthrough wire (Terumo) was advanced easily beyond the lesion in the proximal first diagonal. Rotational atherectomy was not chosen because of the angulated and shelf-like stenosis at the edge of the previously placed stent. A 2.25 × 15 mm compliant balloon would not cross the lesion. A 1.25 × 10 mm compliant and a 1.5 × 15 mm compliant balloon were able to cross the lesion with difficulty. The 2.25 × 15 mm balloon once again failed to cross. A Telescope (Medtronic) 6F GEC was advanced to the ostium of the diagonal, which allowed passage of the 2.25 mm balloon. After that predilation, a 2.5 × 28 mm XIENCE stent was advanced but could not cross beyond the proximal edge lesion. A 0.014-inch Ironman wire (Abbott) was advanced through the GEC, but balloons could not be advanced because of the wire wrap. It was removed, and a 0.014-inch Mailman wire (Boston Scientific) was advanced as a buddy wire. A 2.5 × 15 mm noncompliant balloon was able to be advanced with difficulty and inflated to 26 atm (Figure 4B). The XIENCE stent was readvanced but once again would not cross. The GEC and Runthrough wire were removed, and the 5.5F CrossFAST delivery system was advanced and crossed the proximal edge stenosis with modest effort (Figure 4C). The outer member was advanced to the distal edge of the previously placed stent, and the inner member was removed. The 2.5 × 28 mm XIENCE stent was then advanced easily to the distal end of the CrossFAST outer member, which was then withdrawn to the proximal LAD. Final positioning was performed, and the stent was deployed at 16 atm. Angiography demonstrated good stent expansion with no significant residual stenosis (Figure 4D). The patient was discharged home the same day and had a significant improvement in his angina.

Figure 4.

Case 4. Coronary angiography demonstrates a high-grade, modestly angulated stenosis (arrow) in the proximal segment of a large diagonal branch (immediately proximal to a previously placed stent with moderate, diffuse in-stent restenosis) (A). Predilation performed with difficulty, requiring the use of Telescope guide extension catheter (GEC) and buddy wires (0.014-inch Mailman/0.014-inch Runthrough). The GEC could not be advanced beyond stenosis even with “inch worming” techniques, with the arrow indicating the most distal advancement of the GEC (B). Advancement of the CrossFAST (after removal of the GEC and Runthrough wire) (C) beyond proximal stent edge stenosis (a.), the position of the distal end of the outer catheter (b.), and the microcatheter tip (c.) are indicated. Final result after stent deployment with advancement facilitated by the CrossFAST delivery system (D).

Discussion

Guide catheter extensions have become a cornerstone of contemporary coronary intervention and are used to overcome challenges, including difficult guide catheter engagement, lack of guide catheter support, and vessel calcification or tortuosity.^1,4 Their relevance continues to grow, particularly as radial-access procedures, with inherently reduced guide support, become more prevalent. Guide catheter extensions are now used in an estimated 18% of all PCI and almost 30% of chronic total occlusion PCI.1, 2, 3, 4

There are 2 common general categories of challenging anatomy that call for guide catheter extension use. The first includes challenges of guide engagement and decreased guide support, due to issues like difficult aortic, aorto-subclavian, or aorto-iliac anatomy, inferior or superior coronary artery takeoff, or anomalous aortic origin of coronary artery. In these scenarios, GEC are commonly utilized to provide a bridge between the tip of the guide catheter and the ostium of the coronary artery. This improves backup support by allowing contact and, therefore, “pushability” between the guide catheter and the wall of the aorta opposite the coronary ostium.

The second category of challenges relates to increased friction within the coronary artery itself, which can make delivery of equipment to the target lesion difficult or impossible. This includes issues such as stenosis, coronary vessel calcification, tortuosity, or decreased compliance due to prior stents, which can also coexist to further decrease deliverability. In these cases, it is desirable to deliver a GEC distally, which increases guide support and “pushability,” but more importantly decreases friction within the vessel by providing a lubricious conduit to the distal vessel and, therefore, greatly enhances deliverability.^5,6

The first-generation guide catheter extensions were initially developed in 2009,¹ and include the GuideLiner (Teleflex), the GuideZilla (Boston Scientific), and the Telescope (Medtronic). These are tubular devices with blunt ends delivered over a monorail (Figure 1A, C). For the purpose of improving guide support and device delivery to the proximal vessel, these are easily advanced to the ostial or proximal coronaries, though complications, including coronary artery dissection, perforation, or stent deformation, can still occur because of their blunt-tipped nature.^2,3 This poses increased risk when advancing deeply for the purpose of bypassing high friction within a vessel, which then requires 1 or more of several specific techniques: (1) “inch worming,” in which a balloon is inflated in the vessel just beyond the mouth of the GEC, and the GEC is advanced over the balloon as it deflates; (2) anchor-balloon technique, in which a balloon is inflated in the target lesion, and the GEC is advanced over the shaft of the balloon; or (3) “torpedoing,” in which a balloon is inflated across the mouth of the GEC to provide a smoother transition, and the 2 are then pushed as a unit down the artery. The inchworm and torpedo techniques avoid pushing a blunt-tipped GEC down the artery without a transition. However, the torpedo technique can fail because of the lack of pushability of the GEC. The inchworm technique offers more support, but is time-consuming and can prolong ischemic time, and potentially injure nontarget vessel segments. The anchor-balloon technique is faster, but requires pushing the GEC without a transition and, thus, carries a higher risk of dissection. Additionally, the use of GEC can potentially damage stents being delivered through them, especially those with abluminal polymer coating.⁷

The CrossFAST is a next-generation device delivery system that solves many of the problems associated with GEC, with a tapered inner microcatheter that reversibly “snaps” to the outer catheter at the midshaft coupler. The flexible, 0.018-inch leading (microcatheter) tip, then tapers out proximally to provide a seamless transition to the GEC (outer) catheter (Central Illustration, panels B and C), as well as increased body for pushing, thus eliminating the issues of a potentially dangerous blunt tip and the low pushability of a floppy balloon. The inner catheter is a monorail microcatheter to allow rapid removal once the CrossFAST has reached or passed the target lesion. It is important to note that the pushability of the CrossFAST system is generated by the relatively stiff hypotube of the inner catheter, as the highly flexible nitinol connection to the outer catheter is not capable of advancing the outer catheter forward. In order to advance or readvance the CrossFAST, the inner catheter must be locked into the outer catheter to achieve antegrade pushability (Figure 5). The outer GEC has a 0.046-inch internal diameter and can accommodate most contemporary stents up to 3.5 mm in diameter.

Figure 5.

The proximal (operator) end of the CrossFAST system. The inner and outer catheters in separated (A) and locked (B) positions. In the locked position, there is an edgeless transition between the inner and outer catheters at the distal (coronary) end. The catheter is advanced by pushing the inner catheter, which moves both catheters as a unit.

One limitation is the need to remove side branch wires, as shown in the second case, which may pose an issue when there is significant ostial side branch disease. Additionally, the current generation of CrossFAST cannot accommodate larger stents or the current Shockwave (Shockwave Medical) intravascular lithotripsy catheters. A 6F version with a 0.056-inch inner dimension is expected to be launched in 2026. That version will be capable of delivering IVUS, OCT, and Shockwave.

We describe 4 complex PCI cases in which the CrossFAST system was successfully used to deploy stents after failure of previously available equipment, including conventional GEC. The edgeless transition, pushability, and the lack of need for balloon inflation and deflation allowed rapid delivery of the catheter to the target lesion beyond the calcified, tortuous segments, often to very distal portions of the arteries, while minimizing dissection risk. This is demonstrated by the first case, in which the friction and tortuosity of the vessel were overcome by the CrossFAST to deliver a stent distally, without the need for balloon-assisted tracking, even with a safe but nonsupportive guide. Although the CrossFAST is mostly intended for delivering stents or devices to mid or distal coronary arteries, especially when there is calcium and/or tortuosity, case number 4 demonstrates that even in very proximal LAD lesions, there can be obstructive disease from calcium or poorly deployed stents that can prevent conventional systems from crossing. This is a nice illustration of the use of CrossFAST in an uncrossable proximal lesion, without the need for rotational atherectomy and its inherent risks. In addition, the speed of the sequential GEC system delivery, inner catheter removal, stent delivery, and outer catheter pullback was also paramount to limiting coronary ischemia and maximizing patient safety.

Conclusions

The CrossFAST next-generation device delivery system provides a tapered inner, monorail, microcatheter with a seamless transition to the outer delivery catheter, allowing for safe and rapid delivery of devices to distal coronary arteries, thus minimizing dissection risk and coronary ischemic time. This novel device delivery system can be used safely, effectively, and efficiently to deliver stents beyond calcified and tortuous coronary segments, even when conventional techniques such as buddy wire and GEC have failed. Additional data will be needed to better prove the safety and efficacy of this technology as compared to conventional approaches to PCI in complex CAD.