Catheterization and Cardiovascular Interventions 85:816–817 (2015)
Editorial Comment Smaller May Not Be Better If You Cut Corners James Hansen, DO, and Ian C. Gilchrist,* MD, FSCAI Penn State University, College of Medicine, Heart & Vascular Institute, MS Hershey Medical Center, Hershey, Pennsylvania
Key points
5-Fr transradial sheathless guide technique using a 4-Fr mother–child technique can be accomplished with excellent clinical success An enhanced risk for local traumatic injury to the radial artery was observed that may stem from the imperfect transition and taper between catheters, or friction inherent in the catheter surface design, that technologic advances may be able to address in the future If larger sheath technology is not feasible, this sheathless approach presents an option whether the risk/benefits appear favorable despite the potential from radial artery trauma
Transradial techniques for cardiac catheterization continue to advance despite the anatomical realities that the radial artery is constrained by size and its finite ability to receive equipment for complex interventions. At the end of the procedure, radial artery occlusion (RAO) is associated with the relative vascular sheath size and degree of artery/catheter mismatch, in addition to the method of hemostasis, age, female gender, and body mass [1]. While RAO is usually asymptomatic, its major clinical impact is the loss of future radial access for subsequent procedures. The sheathless guide concept has been promoted as one way to sidestep the anatomic roadblock by using a guide of acceptable internal diameter (ID) with an outer diameter (OD) that is typically 2-Fr size smaller than its corresponding sheath. By eliminating the vascular sheath, the degree of artery/catheter mismatch decreases and the potential for less arterial trauma exists and therefore improved preservation of long-term radial artery function. In practice, sheathless diagnostic angiography is performed with the smallest diameter catheter possible. C 2015 Wiley Periodicals, Inc. V
If disease is found and an intervention is planned, the diagnostic equipment is removed (including the introducer sheath) over a wire and a guide catheter is advanced to the ascending aorta. The percutaneous coronary intervention (PCI) then proceeds in the standard fashion. The invariable cost is localized trauma by repeated cannulation. This trauma may be attenuated by tapering of the catheter assemble as it first enters the artery. Technical developments to this point have used sheathless catheters that have tapered internal dilators or are otherwise tapered in a way that does not require an internal dilator [2,3]. Because these guides are not currently available in the United States, entrepreneurial investigators have developed home grow approaches using available equipment to ease the introduction of catheters into the radial artery without a vascular sheath. The most commonly reported technique is a modified mother–child approach with a diagnostic catheter protruding from the distal end of the guide to provide a pseudo-taper along the passage of the first vascular wire, then diagnostic catheter, followed by guiding catheter into the artery. In this issue, Abdelaal et al. [4] demonstrates the feasibility of sheathless 5-Fr guiding catheters using 4Fr diagnostic catheters as dilators in a mother–child configuration to perform simple and complex PCIs and evaluated access site complications (RAO, pseudoaneurysm, hematoma) using ultrasound. The results show that the transradial PCI approach with this mother–child configuration using a 4-Fr diagnostic within a 5-Fr guiding catheter is feasible with a good success rate (96%) in the setting of fairly complex angioplasty. The rate of radial artery occlusion was 13%, while incidence of pseudoaneurysm and hematoma were 11% and 20%, respectively, and treated conservatively without further complications. Anticipated rate of RAO in transradial catheterization is Conflict of interest: Nothing to report. *Correspondence to: Ian C. Gilchrist, MD, FSCAI, Pennsylvania State University, College of Medicine, 500 University Drive, C1517, Hershey, PA 17033. E-mail: [email protected] Received 5 February 2015; Revision accepted 7 February 2015 DOI: 10.1002/ccd.25888 Published online 18 March 2015 in Wiley Online Library (wileyonlinelibrary.com)
Smaller May Not Be Better If You Cut Corners
2–18% but pseudoaneurysm and hematoma are considered rare events with anticipated rates of only 0.1% and 0.1–1% respectively [5]. Superficially, this suggests an alarming disparity between incident and expected complications. However, the documented rates for these complications are based only on traditional sheathed procedures and most investigations have not been subject to the careful ultrasonic inspection of the access site used in these investigations. Reported complications regarding sheathless catheterization have focused on RAO, as this is the most common complication and the one that the sheathless procedure was specifically intended to reduce. Furthermore, reports of complications from sheathless transradial access (TRA) are relatively rare, and usually do not include pseudoaneurysm or hematoma of clinical significance. It is assumed that these have not been reported because of their rarity and low clinical impact. The diagnostic imaging with ultrasound may also have contributed in the present study in adding numerically to these complications that previously may have been under observation. The authors speculate that the lack of smooth taper is responsible for more local trauma and the observed rate of hematoma and pseudoaneurysm. Studies using sheathless guides with internal dilator, and thus achieving a true smooth taper, have paradoxically not yet shown an improved rate of RAO compared to sheathed technique. All complications are multifactorial in their respective risk factors. Prior studies of sheathless guides did not focus on local pseudo-aneurysm or hematoma, so a true reference point of risk is unknown. The rate of local hematoma and pseudo-aneurysm may be an acceptable norm for sheathless intervention, especially if the sequelae are minimal and resolution is rapid, but the natural history of this complication at the radial artery is unknown. In this series, both the diagnostic and interventional portions of the procedure were performed in a sheathless fashion. It appears likely that the repeated trauma of sheathless catheter exchange may produce a razor effect from the inherent imperfect taper interface between catheters in addition
817
to the potential physical and thermal effects induced by friction induced by catheter exchanges. The effect of catheter friction is best demonstrated by passing a catheter rapidly through a closed hand and the resulting heat of rapid catheter movement can be appreciated. Finally, there was a significant rate of crossover to a sheathed technique (11 patients, 8.5%) for various reasons (significant bleeding, larger bore catheter required, inadequate guide catheter back up) and does support the author’s point on diminishing returns. On the other hand, this is a proof-of-concept paper, and similar comments echo from an earlier era when some first ventured to try 7-Fr guides at a time when 8- and 9-Fr was the de rigueur. Progress never appears initially as perfection, but the pursuit of better (even if smaller) is the drive that keeps innovation alive. REFERENCES 1. Rao SV, Tremmel JA, Gilchrist IC, Shah PB, Gulati R, Shroff AR, Crisco V, Woody W, Zoghbi G, Duffy P, Sanghvi K, Krucoff MW, Pyne CT, Skelding KA, Patel T, Pancholy SB. Best practices for transradial angiography and intervention: A consensus statement from the Society for Cardiovascular Angiography and Intervention’s Transradial Working Group. Catheter Cardiovasc Interv 2014;83:228–236. 2. Mamas M, D’Souza S, Hendry C, Ali R, Iles-Smith H, Palmer K, El-Omar M, Fath-Ordoubadi F, Neyses L, Fraser DG. Use of the sheathless guide catheter during routine transradial percutaneous coronary intervention: A feasibility study. Catheter Cardiovasc Interv 2010;75:596–602. 3. Tonomura D, Shimada Y, Yano K, Ito K, Takehara K, Kino N, Furubayashi K, Kurotobi T, Tsuchida T, Fukumoto H. Feasibility and safety of a virtual 3-Fr Sheathless-guiding system for percutaneous coronary intervention. Catheter Cardiovasc Interv 2014; 84:426–435. 4. Abdelaal E, Rimac G, Plourde G, MacHaalany J, Roy L, Tardif MA, Costerousse O, Pancholy SB,, Bertr OF. 4Fr in 5Fr sheathless technique with standard catheters for transradial coronary interventions: Technical challenges and persisting issues. Catheter Cardiovasc Interv 2015;85:809–815. 5. Kanei Y, Kwan T, Nakara NC, Liou M, Huang Y, Vales LL, Fox JT, Chen JP, Saito S. Transradial cardiac catheterization: A review of access site complications. Catheter Cardiovasc Interv 2011;78:840–846.
Catheterization and Cardiovascular Interventions DOI 10.1002/ccd. Published on behalf of The Society for Cardiovascular Angiography and Interventions (SCAI).
Editorial Comment Smaller May Not Be Better If You Cut Corners James Hansen, DO, and Ian C. Gilchrist,* MD, FSCAI Penn State University, College of Medicine, Heart & Vascular Institute, MS Hershey Medical Center, Hershey, Pennsylvania
Key points
5-Fr transradial sheathless guide technique using a 4-Fr mother–child technique can be accomplished with excellent clinical success An enhanced risk for local traumatic injury to the radial artery was observed that may stem from the imperfect transition and taper between catheters, or friction inherent in the catheter surface design, that technologic advances may be able to address in the future If larger sheath technology is not feasible, this sheathless approach presents an option whether the risk/benefits appear favorable despite the potential from radial artery trauma
Transradial techniques for cardiac catheterization continue to advance despite the anatomical realities that the radial artery is constrained by size and its finite ability to receive equipment for complex interventions. At the end of the procedure, radial artery occlusion (RAO) is associated with the relative vascular sheath size and degree of artery/catheter mismatch, in addition to the method of hemostasis, age, female gender, and body mass [1]. While RAO is usually asymptomatic, its major clinical impact is the loss of future radial access for subsequent procedures. The sheathless guide concept has been promoted as one way to sidestep the anatomic roadblock by using a guide of acceptable internal diameter (ID) with an outer diameter (OD) that is typically 2-Fr size smaller than its corresponding sheath. By eliminating the vascular sheath, the degree of artery/catheter mismatch decreases and the potential for less arterial trauma exists and therefore improved preservation of long-term radial artery function. In practice, sheathless diagnostic angiography is performed with the smallest diameter catheter possible. C 2015 Wiley Periodicals, Inc. V
If disease is found and an intervention is planned, the diagnostic equipment is removed (including the introducer sheath) over a wire and a guide catheter is advanced to the ascending aorta. The percutaneous coronary intervention (PCI) then proceeds in the standard fashion. The invariable cost is localized trauma by repeated cannulation. This trauma may be attenuated by tapering of the catheter assemble as it first enters the artery. Technical developments to this point have used sheathless catheters that have tapered internal dilators or are otherwise tapered in a way that does not require an internal dilator [2,3]. Because these guides are not currently available in the United States, entrepreneurial investigators have developed home grow approaches using available equipment to ease the introduction of catheters into the radial artery without a vascular sheath. The most commonly reported technique is a modified mother–child approach with a diagnostic catheter protruding from the distal end of the guide to provide a pseudo-taper along the passage of the first vascular wire, then diagnostic catheter, followed by guiding catheter into the artery. In this issue, Abdelaal et al. [4] demonstrates the feasibility of sheathless 5-Fr guiding catheters using 4Fr diagnostic catheters as dilators in a mother–child configuration to perform simple and complex PCIs and evaluated access site complications (RAO, pseudoaneurysm, hematoma) using ultrasound. The results show that the transradial PCI approach with this mother–child configuration using a 4-Fr diagnostic within a 5-Fr guiding catheter is feasible with a good success rate (96%) in the setting of fairly complex angioplasty. The rate of radial artery occlusion was 13%, while incidence of pseudoaneurysm and hematoma were 11% and 20%, respectively, and treated conservatively without further complications. Anticipated rate of RAO in transradial catheterization is Conflict of interest: Nothing to report. *Correspondence to: Ian C. Gilchrist, MD, FSCAI, Pennsylvania State University, College of Medicine, 500 University Drive, C1517, Hershey, PA 17033. E-mail: [email protected] Received 5 February 2015; Revision accepted 7 February 2015 DOI: 10.1002/ccd.25888 Published online 18 March 2015 in Wiley Online Library (wileyonlinelibrary.com)
Smaller May Not Be Better If You Cut Corners
2–18% but pseudoaneurysm and hematoma are considered rare events with anticipated rates of only 0.1% and 0.1–1% respectively [5]. Superficially, this suggests an alarming disparity between incident and expected complications. However, the documented rates for these complications are based only on traditional sheathed procedures and most investigations have not been subject to the careful ultrasonic inspection of the access site used in these investigations. Reported complications regarding sheathless catheterization have focused on RAO, as this is the most common complication and the one that the sheathless procedure was specifically intended to reduce. Furthermore, reports of complications from sheathless transradial access (TRA) are relatively rare, and usually do not include pseudoaneurysm or hematoma of clinical significance. It is assumed that these have not been reported because of their rarity and low clinical impact. The diagnostic imaging with ultrasound may also have contributed in the present study in adding numerically to these complications that previously may have been under observation. The authors speculate that the lack of smooth taper is responsible for more local trauma and the observed rate of hematoma and pseudoaneurysm. Studies using sheathless guides with internal dilator, and thus achieving a true smooth taper, have paradoxically not yet shown an improved rate of RAO compared to sheathed technique. All complications are multifactorial in their respective risk factors. Prior studies of sheathless guides did not focus on local pseudo-aneurysm or hematoma, so a true reference point of risk is unknown. The rate of local hematoma and pseudo-aneurysm may be an acceptable norm for sheathless intervention, especially if the sequelae are minimal and resolution is rapid, but the natural history of this complication at the radial artery is unknown. In this series, both the diagnostic and interventional portions of the procedure were performed in a sheathless fashion. It appears likely that the repeated trauma of sheathless catheter exchange may produce a razor effect from the inherent imperfect taper interface between catheters in addition
817
to the potential physical and thermal effects induced by friction induced by catheter exchanges. The effect of catheter friction is best demonstrated by passing a catheter rapidly through a closed hand and the resulting heat of rapid catheter movement can be appreciated. Finally, there was a significant rate of crossover to a sheathed technique (11 patients, 8.5%) for various reasons (significant bleeding, larger bore catheter required, inadequate guide catheter back up) and does support the author’s point on diminishing returns. On the other hand, this is a proof-of-concept paper, and similar comments echo from an earlier era when some first ventured to try 7-Fr guides at a time when 8- and 9-Fr was the de rigueur. Progress never appears initially as perfection, but the pursuit of better (even if smaller) is the drive that keeps innovation alive. REFERENCES 1. Rao SV, Tremmel JA, Gilchrist IC, Shah PB, Gulati R, Shroff AR, Crisco V, Woody W, Zoghbi G, Duffy P, Sanghvi K, Krucoff MW, Pyne CT, Skelding KA, Patel T, Pancholy SB. Best practices for transradial angiography and intervention: A consensus statement from the Society for Cardiovascular Angiography and Intervention’s Transradial Working Group. Catheter Cardiovasc Interv 2014;83:228–236. 2. Mamas M, D’Souza S, Hendry C, Ali R, Iles-Smith H, Palmer K, El-Omar M, Fath-Ordoubadi F, Neyses L, Fraser DG. Use of the sheathless guide catheter during routine transradial percutaneous coronary intervention: A feasibility study. Catheter Cardiovasc Interv 2010;75:596–602. 3. Tonomura D, Shimada Y, Yano K, Ito K, Takehara K, Kino N, Furubayashi K, Kurotobi T, Tsuchida T, Fukumoto H. Feasibility and safety of a virtual 3-Fr Sheathless-guiding system for percutaneous coronary intervention. Catheter Cardiovasc Interv 2014; 84:426–435. 4. Abdelaal E, Rimac G, Plourde G, MacHaalany J, Roy L, Tardif MA, Costerousse O, Pancholy SB,, Bertr OF. 4Fr in 5Fr sheathless technique with standard catheters for transradial coronary interventions: Technical challenges and persisting issues. Catheter Cardiovasc Interv 2015;85:809–815. 5. Kanei Y, Kwan T, Nakara NC, Liou M, Huang Y, Vales LL, Fox JT, Chen JP, Saito S. Transradial cardiac catheterization: A review of access site complications. Catheter Cardiovasc Interv 2011;78:840–846.
Catheterization and Cardiovascular Interventions DOI 10.1002/ccd. Published on behalf of The Society for Cardiovascular Angiography and Interventions (SCAI).
