Optimizing Vascular Access Management — Focus on the Introducer Sheath and Entry Arteriotomy

Results of Pinnacle TIF Tip Sheath Safety and Feasibility Pilot Study

Introduction Vascular access management (VAM) and its complications (VAC) remain a significant source of clinical and therefore economic costs in the interventional treatment of cardiovascular disease. Even with a trend towards a decreasing incidence of VAC in the last decade, VAC during percutaneous coronary interventions (PCI) have been reported between 0.4 – 27%, depending on the definition of complications.1-5 It is now clear that even with a “minor” complication, there are significant clinical, ischemic and economic VAC costs, with multiple recent reports of increased in-house, 30-day and one-year mortalities and morbidities now associated with VAC during PCI.5-10 Sparse data exists regarding the incidence or costs of VAC during percutaneous peripheral vascular interventions (PVI) but a review of the literature cites an incidence of 3.5% – 32.7%.11-13 Shammas recently reported a 16% VAC incidence in 131 PVI with a death rate (0.8%), limb loss (1.5%), major bleeding (4.6%), urgent revascularization (7.6%) and vascular complications (1.5%).11 Minor complications were not categorized in this report, thus likely underestimating the true clinical impact of VAC. In a just-published report, Dick et al evaluated VAC in 619 consecutive PVI cases and focused on VAC in octogenarians.14 Complication rates were significantly higher in octogenarians compared to patients below 80 years, including the rates of overall complications (18.1% versus 8.5%, p = 0.010), major complications (11.1% versus 1.8%, p Background Interestingly, transfemoral CFA access has remained the preferred percutaneous vascular access entry, with little change in an overall VAM strategy since its original description by Selinger in 1953.15 Over the last decade, multiple vascular closure devices (VCD) have been developed in an attempt to facilitate VAM and final arteriotomy closure without significantly decreasing VAC. VCDs have even created a “new disease” with their own, real-world set of catastrophic VCD complications, including infection, vessel thrombosis, vessel injury, embolization, limb loss and even death (Figure 1). The VCD approach to facilitate VAM has focused on device-orientated manipulation of the already created arteriotomy site. This approach invariably leaves some form of “VCD debris” (suture, anchor, collagen, clip, plug, staple, glue, etc.) at the arteriotomy site and within the arteriotomy tract that may result in significant perivascular scarring. VCD debris potentially has a negative effect on future CFA re-access, and the need for re-access is becoming more common in our cardiovascular patients, especially patients requiring PVI. Until recently, little attention has been given to VAM regarding vascular access beginning at the skin level. It is now accepted that detailed attention to the bony elements of the groin (head of femur, iliac rim, pelvic rim, etc.) and vascular wall calcifications under fluoroscopy should be given on all “CFA sticks,” which likely will decrease VAC. All “CFA sticks” are performed in this manner in our cath lab. Various Doppler-assisted devices and micropuncture kits are also now available to facilitate more complex CFA accesses. Little attention and few technical advancements have been made in introducer sheath technology despite “difficult groin access” cases becoming more frequent occurrences in all our labs secondary to previous surgical procedures, multiple previous access, older age populations, more frequent, heavily calcified CFAs, more PVI cases, and now a decade of patients harboring a host of VCD debris-scar in their groins and on the CFA wall. It is becoming commonplace, especially for those labs doing high-volume PVI, to encounter patients in which safe and uncomplicated introducer sheath access can be problematic. Access can generally be gained, but often requires multiple extra steps, wires, dilators, sheath exchanges, devices, excessive penetration forces and maneuvers, etc., and exposes the patient and staff to additional fluoroscopy, economic costs and potentially increased VAC. This difficulty in advancing the introducer sheath set into the CFA lumen is invariably secondary to excessive perivascular tissue scarring from the dermis to the intima, and an attempt was made previously with an intraoperative study to subjectively categorize this phenomenon with the description of the perivascular scar score.16 It could be theorized that increased VAC might be associated with the creation of the arteriotomy during the “CFA stick” and with the advancement of the introducer sheath through the subdermal, subcutaneous and perivascular tissues, and vessel wall. It seems intuitive that the creation of a smooth, atraumatic arteriotomy would be better suited for uncomplicated final hemostasis, regardless of the final arteriotomy management or closure (manual compression or VCD). Likewise, it seems a reasonable assumption that a more traumatic tissue tract advancement and arteriotomy site creation would be associated with an increased perivascular and tissue tract bleeding, inflammation, scarring and therefore, VAC. Few recent advancements have been made with introducer sheath technology, especially regarding the transition zone between the wire and introducer sheath tip and the dilator. In a “difficult to access” or “scarred groin,” it is believed that excessive resistance to sheath set penetration can occur at this transition zone, resulting in a failure to gain vessel access due to several sheath set failures, including kinking, sheath fish-mouthing or sheath peeling. Terumo Interventional Systems (Somerset, NJ) has developed the Pinnacle Total Integrated Fit (TIF) Tip™ introducer sheath system, designed to bend and flex without gapping, kinking or producing sharp crimps, to potentially facilitate vascular access and minimize potential trauma (Figure 2A-B). TIF technology was developed with a unique manufacturing process that creates a super-fine tapered edge and super-smooth transition from dilator-to-sheath and guidewire-to-dilator (Figure 2C). The dilator taper is more gradual and much smoother than traditional sheaths (Figure 2 D-E). The dilator outer diameter (OD) and sheath tip inner diameter (ID) are perfectly rounded, with tighter tolerances eliminating any gaps or irregularities at the sheath tip (Figure 2F). The dilator lumen is perfectly rounded at the tip with an improved transition to the wire, facilitating optimal wire placement through the entire dilator-sheath assembly (Figure 2F). In bench-top tests, the Pinnacle TIF Tip required up to 24% less penetration force in vascular entry than traditional sheaths. Additionally, the TIF Tip sheath flexed beyond 45° without kinking or collapsing, whereas all other traditional sheaths consistently kinked at 45°. It was hypothesized that these sheath characteristics may facilitate vascular access, resulting in easier, safer introducer sheath access with the potential for less VAC. The Terumo Pinnacle TIF Tip Set Study was a 3-month pilot safety and feasibility experience utilizing the TIF sheath in a high-volume cath lab that primarily performs complex PVI. Methods The Pinnacle TIF Tip sheath pilot study was a 3-month (February – May 2008), prospective, non-randomized, single-center clinical experience conducted at Southwest Medical Center (Lafayette, LA), a high-volume tertiary referral facility for complex PVI, especially critical limb ischemia (CLI) and limb salvage. Prospective and retrospective data was collected and recorded according to HIPAA standards by a trained clinical research nurse and audited by a monitoring coordinator. Study endpoints included completion of a subjective sheath performance characteristic matrix of the TIF sheath, overall access site complications at hospital discharge and any access site-related blood loss. Multiple additional periprocedural variables were collected, including: previous use of access site, sheath sizes, specific procedure performed, bleeding upon sheath removal, sheath-induced complications, type of closure system/device used and each operator’s subjective categorization of each “groin stick” into normal-mild, moderate or severe scarring at the access site. This subjective categorization was based on the intraoperative perivascular scar score that has been published previously.16 A subjective sheath performance matrix was created to subjectively assess each case by asking the operator to grade a series of 11 sheath performance characteristics. On each data collection form, the operator was asked to provide a subjective evaluation of the TIF sheath relative to the 11 performance characteristics, based on a grading scale of 5 through 1, with 5 representing “excellent performance” and 1 representing “failure to achieve access” (Table 1). The following sheath performance characteristics and definitions were included in the matrix: 1. Durability – the ability of the sheath to withstand all peri-procedural device exchanges. 2. Fish-mouthing – uneven ovaling of the distal opening of the sheath, resulting when the sheath slips back off the dilator due to penetration resistance or sheath transition mismatch. 3. Kinking – any buckling or bending of the wire, sheath or dilator shaft during advancement over the wire. 4. Peeling – the sheath folding over itself, bunching on top of the dilator (accordination of the sheath). 5. Stiffness – the support and stoutness of the shafts of both the sheath and dilator. 6. Tractability – the ability of the sheath to follow the wire through the skin and in the vessel, and not buckle or kink. 7. Visualization – ability to visualize the system under fluoroscopy. 8. Resistance – amount of pressure required to advance the sheath set through the tissues to gain vascular access. Wire/dilator/ sheath kinking or fish-mouthing may be associated with increased resistance. Extreme insertion forces (penetration force) may be associated with vessel wall (including intimal) trauma and arteriotomy site injury or widening. 9. Penetration force – the subjective measure of pressure required to insert the sheath and dilator into the vessel (Scale of 1 = easy to 5 = unable to access). 10. Tactile feel – the tactile sensation felt by the operator as the sheath set is advanced over the wire and through the tissues. This includes pushability, force, stiffness, traceability, resistance and friction to movement, and tells the operator that the distal end of the system is advancing properly through the tissues and into the vessel. The previously described intraoperative observational perivascular scar score was developed during 150 CFA exposures during abdominal aortic aneurysm (AAA) – endovascular aortic aneurysm repair (EVAR) procedures between 2001–2003, and represents the first attempt to objectively categorize the subcutaneous and perivascular scar (reaction) 1-4 weeks after non-complicated percutaneous CFA vascular access.16 A silicone benchtop model was designed by these same operators in an effort to create a subjective percutaneous groin “scar score” equivalent for this study. Therefore, the definition of the percutaneous “scar score” used in this study would include normal–mild, which would correspond to a non-operated-on groin with a non-calcified CFA on fluoroscopy with 0-1 previous CFA “sticks.” The access site in this category would have a mild scarring, which would result in a normal stick or minimal additional penetration force, as grossly the perivascular tissue would exhibit mild fibrosis with mild adventitial and medial wall thickening with an intact vaso vasorium (Figure 3A). Moderate scar scoring categorization during the TIF pilot study would result from a groin with 0-1 previous surgical operations, 1-3 previous CFA “sticks” and mild–moderate CFA calcification on fluoroscopy. Grossly, this would correlate to moderate subcutaneous and perivascular fibrosis, with definite adventitial and medial vessel thickening and calcification (Figure 3B). A severe percutaneous “scar score” categorization in the TIF pilot study would include 1-3 previous groin operations, greater than 3 previous CFA “sticks” and severe CFA calcification on fluoroscopy. Grossly, this would correlate with severe subcutaneous tissue fibrosis and scar, which intraoperatively would require extensive surgical dissection and provide excessive operative bleeding (Figure 3B). Severe vessel wall thickening and calcification would result in the surgeon altering a traditional arteriotomy site on the anterior surface of the CFA in the original intraoperative perivascular scar score description (Figure 3C). Currently, in our practice, computed tomographic angiography (CTA) increasingly identifies potential CFA access site problems (Figure 3D-E). Patients were pre-treated with aspirin (300–325 mg po) and clopidogrel (Plavix, Bristol-Myers Squibb/ Sanofi Pharmaceuticals, Bridgewater, NJ) (75–375 mg po) up to 12 hours prior to the intervention. Bivalirudin (Angiomax, The Medicines Company, Parsippany, NJ) was administered intravenously at a dose of 0.75 mg/kg bolus followed by an infusion of 1.75 mg/kg/hour for the duration of the procedure. Glycoprotein (GP) IIb/IIIa inhibitors were permitted at the discretion of the treating physician, with all CLI patients [91/184 (49.4%)] receiving tirofiban (Aggrastat, Medicure, Winnipeg, Manitoba, Canada), 10 mcq/kg/min bolus with 8-12 hours 0.1 mcq/kg/min postprocedural infusion. All CFA “sticks” were performed under fluoroscopy with attention to bony landmarks and vessel calcification. Final arteriotomy site closure was managed as follows: 47 = traditional sole manual compression, 75 = the Cardiva Catalyst™ (formerly “Boomerang”) (Cardiva Medical, Inc., Mountain View, CA) and 50 = D-Stat (Vascular Solutions, Minneapolis, MN) system and 17 cases used Catalyst plus D-Stat. Post-procedural targeted renal therapy (TRT) using the 5-Fr Benephit catheter (Flowmedica, Inc., Fremont, CA) was utilized in 29/189 (15.3%) of cases identified with a creatinine clearance of Results There were 189 patients enrolled during the TIF study, with the procedure breakdown as follows: PVI = 136, coronary procedures = 55 (PCI = 45 and diagnostic = 10) and 2 patients had combined procedures. Sheath sizes included: 5-Fr = 28, 6-Fr = 155, 7-Fr = 8 and 8-Fr = 1. Access site included right CFA = 135, left CFA = 55 and one case required bilateral CFA access. A skin nick incision was used in 5/189 (2.6%) cases, while 184/189 (97.4%) required no skin nick. In our lab, skin nicks are reserved only for cases with an initial failure to introduce the sheath through the skin. First-time CFA access was recorded in 59/189 (31.2%) cases, with 45/59 (76.2%) being coronary procedures. Repeat access was recorded overall in 130/189 (68.8%), with 123/130 (94.6%) being greater than two previous CFA access “sticks.” The overall study incidence of greater than two previous access site sticks was 123/189 (65.1%). The overall incidence of greater than two previous access sticks in PVI cases was 109/136 (80.1%). There were no device-related complications, retroperitoneal hematomas, pseudoaneurysm, surgical complications or access site-related blood transfusions. Minor hematoma (Discussion Primary focus on the role of arteriotomy creation and the transition of the introducer sheath set from skin to intima relative to the overall incidence of VAC is a novel concept. Regardless of VAM, smooth and uncomplicated CFA vascular access is integral to the performance of any case. Also, regardless of VAM, the elimination of additional steps, devices and maneuvers to secure vascular access during a “difficult access” would be desirous from a time, resource, fluoroscopy and economic standpoint. Examples of such eliminated additional maneuvers would include the need for multiple additional wires for extra support (Amplatz Stiff Wire, Cook Medical, Inc., Bloomington, IN), need to utilize different sizes and designs of dilators or additional sheaths, use of a micropuncture or similar small-profile hydrophilic sheath immediately over the wire to gain dilator access, skin incisions or “nicks,” subcutaneous tissue tract dilation with a hemostat and the use of excessive wire straightening, and penetration force to gain intraluminal entry of the introducer sheath set. The above examples are some of the additional maneuvers used to gain vascular access in a “scarred groin” that were almost totally eliminated in this 189-patient experience. It seems reasonable to assume that the elimination of these extra maneuvers and the elimination of vascular, perivascular and subdermal trauma with a smooth, uncomplicated introducer sheath entry would have potential clinical and economic benefits. The elimination of all major VAC and only 1/189 (0.5%) incidence of minor hematoma ( 2 times. To our knowledge, this is the first study that collected, documented and analyzed re-accessed CFA sites in PCI or PVI. Additionally, 91/189 (48.1%) of the cases utilized GP IIb/IIIa inhibitors, which in most reports has resulted in increased VAC, especially when combined with unfractionated heparin (UFH).17-18 When compared to our match HC group from 2007, the TIF study group results revealed significantly less major and minor VAC. This HC group was treated exactly the same by the same operators, except the use of multiple different introducer sheath set systems. During the immediate 30 days after the pilot study, the TIF sheath set study product was removed from our lab and not available for use. An obvious distinct difference was noted by all study operators and cath lab technologists. A 30-day post study internal analysis of our cases without TIF technology revealed a major VAC incidence of 1/63 (1.5%), with minor VAC incidence of 2/63 (3.2%) with 2 minor hematomas (Limitations Limitations inherent in this pilot study include the lack of a randomized control arm, the use of a non-randomized, retrospective matched HC for comparison, a single-center experience, the relatively small patient sample size, and the potential for observational and selection bias inherent to all non-randomized study designs. There were no bypass grafts accessed in this study. It would also be interesting to evaluate a similar patient population using UFH. Economic data, additional use of wire, dilator, sheaths and additional periprocedural maneuvers to facilitate groin access in a “scarred groin” were not collected in this study, but should be added to future investigations to fully quantify the TIF sheath influence during each case. Conclusion The incidence of VAC remains a major source of clinical and economic costs to our patients and cath labs, especially the PVI patient, who appears to be at particularly higher risks for complications. Increasingly greater numbers of patients are being delivered to our cath labs or endovascular suites requiring vascular access in scarred groins that have been previously accessed, which often provide a challenge to safe re-access. Little is known and few resources have been dedicated into investigating the relationship of the introducer sheath set transition zone and its role in creating or limiting vascular access tissue site trauma, especially at the precise arteriotomy level. The Pinnacle TIF Tip sheath pilot safety and feasibility study results revealed an excellent sheath performance matrix with a very low VAC rate in a higher-risk patient population. These results indicate that more focus needs to be dedicated to the role of the introducer and interventional sheath set in VAC. Clinical and economic outcomes may be potentially optimized with this novel, more contemporary transition zone technology. It is very likely that VAC are associated with both how we create the arteriotomy and how we close the arteriotomy. A larger, randomized, multi-center study incorporating appropriate clinical and economic endpoints is warranted to validate these results and document efficacy. Acknowledgement The authors would like to thank Kelly Tilbe, NCMA, for her help with technical manuscript preparation. Disclosure: Drs Allie and Walker disclose that they are members of the medical advisory board, consultants and equity holders in Cardiva Medical, and consultants to Terumo Medical Corporation. Terumo supplied a research grant for the pilot trial. Mr. Hebert, Dr. Patlola, Dr. Ingraldi and Ms. Landry have nothing to disclose.

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