Cardiovascular Revascularization Medicine 14 (2013) 275–279
`
`Contents lists available at ScienceDirect
`
`Cardiovascular Revascularization Medicine
`
`Transradial interventions with the GuideLiner catheter: Role of proximal
`vessel angulation
`Moneer J. Eddin, Ehrin J. Armstrong, Usman Javed, Jason H. Rogers ⁎
`University of California, Davis Medical Center, Division of Cardiovascular Medicine, Sacramento, CA
`
`a r t i c l e
`
`i n f o
`
`a b s t r a c t
`
`Article history:
`Received 25 May 2013
`Received in revised form 3 July 2013
`Accepted 11 July 2013
`
`Keywords:
`Transradial
`Coronary intervention
`Angiography
`
`Background: Transradial coronary intervention (TRI) is increasingly common, but anatomic variations and
`lack of guide catheter support may increase the complexity of TRI. The GuideLiner catheter (Vascular
`Solutions, Minneapolis,MN) is a guide catheter extension developed to provide increased guide catheter
`support. We hypothesized that TRI cases requiring GuideLiner support would have a greater proximal vessel
`angle and increased lesion angle tortuosity.
`Methods: This was a retrospective study reviewing 146 TRI cases performed at a single institution between
`August 2010 and June 2012. 22 cases (15%) required use of the GuideLiner support catheter. Procedural and
`angiographic characteristics of all cases were analyzed. Multivariable analysis and receiver operator curves
`(ROC) were used to analyze predictors of GuideLiner use.
`Results: The indications for TRI were similar between both groups. Subjects who required use of the
`GuideLiner support catheter at the time of TRI were significantly older (69 ± 12 years vs. 62 ± 13 years,
`p = 0.03). The proximal vessel angle was significantly greater in the cases requiring GuideLiner support
`(74° ± 35° vs. 37° ± 23°, p b 0.001). Lesion angle in the Guideliner group was also significantly greater
`(48° ± 32° vs. 28° ± 25°, p b 0.001). On multivariable analysis, proximal vessel angle independently
`predicted the need for GuideLiner support (AOR 1.4 per 10°, p b 0.001). A 45° proximal vessel angle predicted
`the need for GuideLiner use with a sensitivity of 73% and specificity of 74% (c-statistic 0.79). None of the
`Guideliner TRI cases required conversion to femoral access.
`Conclusions: TRIs requiring GuideLiner catheter support had significantly increased lesion complexity and
`vessel tortuosity. Proximal vessel angulation is significantly associated with the need for GuideLiner use
`during transradial intervention. Use of the Guideliner facilitated successful completion of PCI despite the use
`of a wide variety of guiding catheters in this series.
`
`© 2013 Elsevier Inc. All rights reserved.
`
`1. Introduction
`
`Transradial coronary intervention (TRI) is associated with signif-
`icantly reduced rates of bleeding and access site related complications
`[1] compared to the transfemoral (TF) approach. Although TRI is
`increasingly common, it currently represents b10% of all PCIs in the
`USA. Barriers to TRI include a steep initial learning curve and time
`required to gain proficiency at TRI [2]. Additionally, anatomic
`variations and lack of guide catheter support increase the technical
`complexity of TRI [3,4].
`During trans-radial cardiac catheterization, the anatomic and
`geometric characteristics of the ascending aorta relative to the
`catheter differ significantly from TF angiography. Specifically, guide
`catheters advanced from the right radial artery often approach the
`coronary ostia from a vertical downward approach, which excludes
`the aortic arch. As a result, less guide backup force is generated [5].
`
`⁎ Corresponding author. 4860 Y Street, Suite 2820, Sacramento, CA 95817. Tel.: +1
`916 7343764; fax: +1 916 7348394.
`E-mail address: jason.rogers@ucdmc.ucdavis.edu (J.H. Rogers).
`
`1553-8389/$ – see front matter © 2013 Elsevier Inc. All rights reserved.
`http://dx.doi.org/10.1016/j.carrev.2013.07.004
`
`Since most guide catheters were also designed for a TF approach, they
`may provide less backup support and coaxial alignment for TRI. One
`technique to overcome lack of guide catheter support includes deep
`intubation of the guide catheter. However, most guide catheters are
`designed for support at the coronary ostia and such maneuvers can
`traumatize the target coronary artery [6]. More aggressive radial-
`specific guides can also be used, but these may also result in proximal
`vessel injury. With many new operators adopting radial catheteriza-
`tion and TRI, improved techniques to facilitate successful completion
`of the procedure could have significant advantages.
`The GuideLiner catheter (Vascular Solutions, Minneapolis, MN) is a
`novel “mother and child” rapid exchange atraumatic guide catheter
`extension that allows deep vessel intubation with minimal trauma to
`the native coronary artery. Early reports demonstrated successful
`application of this catheter extension for complex TF coronary
`interventions including vein and LITA grafts [7–10]. However, no
`prior study has examined the utility and predictors of GuideLiner use
`as an adjunctive tool for TRI.
`In this study, we characterized the procedural and angiographic
`characteristics of cases where GuideLiner use facilitated successful
`
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`Fig. 1. Measurement of Proximal Vessel and Lesion Angulation. (A) Right Coronary Artery in LAO projection with overlaid measurements of proximal vessel and lesion angulation and
`(B) Left Circumflex Artery in LAO Caudal projection with overlaid measurement of proximal vessel angulation. Lesion(s) denoted by black arrows with white border.
`
`TRI. We hypothesized that cases requiring the use of a GuideLiner
`catheter would have a higher prevalence of proximal angle and lesion
`angle tortuosity, and that GuideLiner use would be associated with
`high rates of procedural success and minimal need for crossover to a
`TF approach.
`
`2. Methods
`
`A total of 1292 PCIs were performed between August 2010 and
`June 2012 at the University of California, Davis Medical Center.
`During that
`timeframe, 146 of
`these cases were TRI, which
`comprise the study cohort. Among these 146 TRIs, 22 cases
`(15%) required use of the GuideLiner support catheter. The general
`approach to TR and TF intervention at our institution is to attempt
`PCI with conventional guide support, and to use a GuideLiner only
`in those cases where it became difficult or not feasible to deliver
`therapy to the target lesion. Thus, the use of the GuideLiner was at
`the operator’s discretion. We analyzed patient characteristics,
`procedural characteristics, and angiographic variables of all TRIs.
`The following patient characteristics were determined: patient
`age, gender, demographic factors, and the indication for interven-
`tion. The following procedural characteristics were assessed:
`access site, target vessel, ACC/AHA lesion type (A, B1, B2, C)
`[11], size of the guide catheter, types of balloons/stents delivered,
`and procedural success. Procedural success was defined as final
`target lesion stenosis of b20% with TIMI 3 grade flow without
`major complications.
`Angiographic variables quantified included: lesion length, vessel
`diameter proximal and distal to the target lesion, and lesion
`calcification. Proximal vessel and target lesion angulations (Fig. 1)
`were classified as minor (b45°), moderate (45°–90°), or excessive
`(N90°) [12]. Proximal vessel angulation was defined as the angle
`closest to the target lesion of interest. If the target vessel contained
`more than one angulation before the target stenosis, the angle
`immediately proximal to the lesion was taken. Vessel angulations
`were measured using QCA in the projection least likely to
`foreshorten the vessel of interest (Phillips Xcelera,The Netherlands).
`For example, the right coronary artery (RCA) was measured in the
`left anterior oblique (LAO) projection, left anterior descending (LAD)
`and left circumflex (LCx) takeoff was measured in LAO caudal
`projection, diagonal branches in the LAO cranial projection, and
`obtuse marginal (OM) branches were measured in the right anterior
`oblique (RAO) caudal projection. All vessel measurements were
`
`performed and verified independently by two cardiologists experi-
`enced in QCA analyses.
`
`2.1. Statistical analysis
`
`Mean values with standard deviation were used to describe
`continuous variables, and numerical counts (percentages) were used
`for categorical variables. Statistical analysis was performed by means
`of Pearson chi-square test for categorical variables. Student's t-test
`was used to test for differences in continuous variables. All values
`were expressed as mean ± SEM. Statistical significance was accepted
`with a p value of less than .05. A logistic model was developed to
`identify independent predictors of GuideLiner support catheter use by
`including all angiographic variables that were significant on univar-
`iate analysis using a cutoff of p b 0.1 for inclusion. Receiver operator
`curves of sensitivity vs. 1-specificity were constructed to identify the
`proximal vessel angle that maximized sensitivity and specificity for
`predicting GuideLiner use. All statistical analyses were performed
`using STATA version 11.2 (College Station, TX). All authors had full
`access to and take full responsibility for the integrity of the data. All
`authors have read and agree to the manuscript as written.
`
`3. Results
`
`Among 146 TRIs performed during the study period, 22 cases
`(15%) required use of the GuideLiner support catheter during TRI.
`Demographic data comparing baseline characteristics of subjects are
`
`Table 1
`Baseline demographics.
`
`Variable
`
`GuideLiner (N = 22) No GuideLiner (N = 124) P value
`
`15 (68)
`69 ± 12
`
`Male (%)
`Age, years
`Indication
`10 (45)
`Elective
`12 (55)
`ACS
`17 (77)
`Hypertension (%)
`16 (73)
`Hyperlipidemia (%)
`11 (50)
`Diabetes (%)
`2 (9)
`Active smoker (%)
`Family history of CAD 1 (5)
`Prior MI
`2 (9)
`Prior PCI
`6 (27)
`Prior CABG
`6 (27)
`
`95 (77)
`62 ± 13
`
`49 (40)
`75 (60)
`95 (77)
`66 (53)
`47 (38)
`28 (23)
`7 (6)
`12 (10)
`25 (20)
`21 (17)
`
`0.4
`0.03
`0.6
`
`0.9
`0.09
`0.3
`0.1
`0.8
`0.9
`0.5
`0.3
`
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`Table 2
`Angiographic and procedural characteristics.
`
`Table 4
`Patient outcomes.
`
`Variable
`
`Guideliner
`(N = 22)
`
`No Guideliner
`(N = 124)
`
`P value
`
`Variable
`
`Guideliner
`(N = 22)
`
`No Guideliner
`(N = 124)
`
`P value
`
`Access Side
`Right
`Left
`Both
`Femoral Conversion
`Target Vessel
`RCA
`LAD
`Circumflex
`Bypass Graft
`Left Main
`Lesion Category
`A
`B1
`B2
`C
`Calcification
`None
`Mild
`Moderate
`Severe
`Multiple Guide Catheters used(≥2)
`Final Guide Catheter Used
`Right Coronary
`JR
`AL1
`AL 0.75
`AR1
`Left Coronary
`JL
`XB
`XBLAD
`EBU
`Q
`Ikari
`AL
`Embolic Protection
`Lesion Length
`Proximal vessel, mm
`Distal vessel, mm
`Total stents delivered
`Post Procedure TIMI flow b3
`Vessel complications
`Lesion angle
`Proximal vessel angle
`
`13 (59)
`8 (36)
`1 (5)
`0 (0)
`
`12 (55)
`5 (23)
`5 (23)
`0
`0
`
`1 (1)
`1 (1)
`6 (27)
`14 (64)
`
`5 (23)
`6 (27)
`7 (32)
`4 (18)
`4 (18)
`
`9(75)
`1(8)
`1(8)
`1(8)
`
`3(30)
`2(20)
`0
`0
`4(40)
`0
`1(10)
`1 (5)
`28 ± 22
`2.4 ± 0.6
`2.3 ± 0.7
`1.9 ± 1.3
`0
`0
`48 ± 32
`74 ± 35
`
`89 (72)
`33 (27)
`2 (2)
`2 (2)
`
`42 (34)
`46 (37)
`26 (21)
`1 (1)
`9 (7)
`
`18 (15)
`36 (29)
`30 (24)
`40 (32)
`
`72 (58)
`29 (23)
`16 (13)
`7 (6)
`18 (15)
`
`33(78)
`4(10)
`4(10)
`1(2)
`
`27(33)
`10(12)
`3(4)
`17(21)
`19(24)
`1(1)
`4(5)
`5 (4)
`19 ± 14
`2.6 ± 0.7
`2.3 ± 0.6
`1.5 ± 1.1
`2 (2)
`6 (5)
`28 ± 25
`37 ± 23
`
`0.4
`
`0.6
`0.3
`
`0.01
`
`0.005
`
`0.7
`
`0.9
`0.02
`0.3
`0.9
`0.2
`0.5
`0.3
`b0.001
`b0.001
`
`summarized in (Table 1). The indications for TRI were similar between
`both groups, with slightly over half of the procedures performed for
`acute coronary syndrome. Subjects who required use of the Guide-
`Liner support catheter at the time of TRI were significantly older
`(69 ± 12 years vs. 62 ± 13 years, p = 0.03). The two groups had
`otherwise similar baseline demographic characteristics.
`Procedural and angiographic details of the 146 TRI cases are
`reported in (Table 2). A wide variety of 6 French guiding catheters
`were used by the multiple operators who participated in this series
`highlighting the diversity of approaches seen in clinical practice. Cases
`requiring GuideLiner use were more likely to involve intervention to
`
`Table 3
`Univariate predictors of Guideliner use.
`
`Predictors
`
`Unadjusted Odds Ratio
`
`Right Coronary Artery
`Calcification
`Lesion length, per 10 mm
`Lesion Angle, per 10°
`Proximal Vessel Angle, per 10°
`Age, per 10 years
`
`2.3 [0.94–5.9]
`4.7 [1.6–13.6]
`1.3 [1.1–1.5]
`1.2 [1.1–1.4]
`1.4 [1.2–1.6]
`1.4 [1.1–1.8]
`
`P value
`
`0.07
`0.004
`0.02
`0.002
`b0.001
`0.03
`
`Procedural Success
`Angiographic Success
`Major Bleeding
`Femoral Conversion
`Post Procedure TIMI flow b3
`Vessel complications
`(Dissection or perforation)
`
`22 (100)
`22 (100)
`0
`0
`0
`0
`
`124 (100)
`122 (98)
`0
`2 (2)
`2 (2)
`6 (5)
`
`1.0
`0.9
`N/A
`0.6
`0.5
`0.3
`
`the RCA (55% vs. 34%). Several angiographic variables also differed
`between the two groups. The proximal vessel angle was significantly
`greater among cases that required GuideLiner support (74° ± 35° vs.
`37° ± 23°, p b 0.001). Lesion angle was significantly greater among
`patients that required GuideLiner support (48° ± 32° vs. 28° ± 25°,
`p b 0.001). Vessel calcification, lesion complexity, and lesion length
`were significantly greater in the GuideLiner cases (28 ± 22 vs. 19 ±
`14 mm, p = 0.02). Mean maximal GuideLiner intubation depth as
`measured from the coronary ostium was 23 ± 21 mm.
`On univariate analysis, predictors of GuideLiner use included
`proximal vessel angulation, lesion angle, lesion length, and lesion
`calcification (Table 3). On multivariable analysis, only proximal vessel
`angulation was remained a significant determinant of GuideLiner use
`(adjusted Odds Ratio 1.4 [95% CI 1.2–1.6] for each 10° of increased
`proximal vessel angulation, p b 0.001). Receiver operator curve
`analysis of proximal vessel angulation revealed that a proximal vessel
`angle of 45° had a sensitivity of 73% and specificity of 74% for
`predicting need for GuideLiner support during TRI (c-statistic 0.79).
`The procedural success was 100%, the majority of cases were
`performed through the right radial artery access. No major compli-
`cations were seen. None of the TRI cases in which the GuideLiner was
`used required conversion to femoral access (Table 4).
`
`4. Discussion
`
`Enthusiasm for transradial intervention (TRI) is often high during
`an operator’s early experience with transradial catheterization due to
`reported benefits related to increased patient comfort and decreased
`bleeding complications. However, there are inherent challenges to the
`transradial technique, and inadequate guide support and difficulty in
`completing interventions that might be more easily accomplished
`from the more familiar femoral approach can dampen enthusiasm.
`Despite the availability of radial-specific guiding catheters, these
`guides tend to be more aggressive and many operators prefer
`femoral-type curves which are more familiar. It is therefore important
`
`Fig. 2. Support Angulation During Coronary Intervention. Representation of the Ikari
`hypothesis and the role of support point angulation in generating back up force.
`
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`Fig. 3. Example of Deep Vessel Intubation with Guideliner. (A) Long mid-left circumflex lesion extending into a left posterolateral branch (White Arrow/Black Border) with tortuous
`proximal vessel (retroflexed circumflex origin). (B) Deep intubation with GuideLiner (Dashed Black Arrow) for stent delivery. (C) Left Circumflex artery after deployment of
`overlapping 2.5 × 28 mm 2.5 × 18 mm DES (Black Arrows).
`
`to identify techniques that can facilitate TRI and ensure more
`consistent procedural success.
`In this study, we describe the
`angiographic characteristics of lesions that were more likely to
`necessitate GuideLiner support during TRI. The major finding of this
`study is that proximal vessel angulation is an important predictor of
`need for GuideLiner support, suggesting that this vessel characteristic
`could be used at the start of TRI to predict the need for more active
`guide support. With the use of this guide catheter extension
`technique, procedural success rates were very high (100%) and not
`different from transradial interventions that did not require Guide-
`Liner support.
`Despite advances in guide catheter design and procedural
`techniques for coronary revascularization, adequate guide support
`continues to be a challenge, especially for complex coronary in-
`terventions through the transradial approach. Because of the angle
`between the innominate artery and ascending aorta, some of the
`principles of adequate backup support are lost when approaching TRI,
`particularly through the right radial artery. Those principles include
`an ideal supportive point directly opposite the coronary ostia. Ikari et
`al. have hypothesized that the backup force of that supportive point is
`directly proportional to two main factors: (1) Static friction (λ), as the
`length of guide catheter in contact with backwall of the aorta is
`increased, more friction is created and less chance of displacement;
`and (2) The angle made between guide catheter contact point along
`the contralateral aortic wall. The angle between the guide catheter
`and the backwall of the aorta is increased as the contact point of the
`
`guide catheter sits lower on the aorta, thereby increasing support
`forces in parallel with the coronary ostium (Fig. 2) [13–15]. Each of
`these support factors is potentially compromised during TRI, thereby
`decreasing guide catheter support and making the procedure more
`technically challenging.
`Numerous approaches have been described to overcome the need
`for increased support during device delivery. These techniques
`include extra backup guides, dedicated radial support guides (which
`tend to be more aggressive), stiffer guidewires, buddy wires, and the
`anchor balloon technique [16,17]. The operator can also upsize to a
`larger guide for increased backup support; however, this option is
`more limited when performing a TRI due to the smaller caliber of the
`radial artery. Certain TRI cases can prove quite difficult despite these
`techniques, and in the past may have required conversion to femoral
`access for increased support [18]. However, the development of guide
`catheter extension systems such as the GuideLiner has provided an
`additional tool to help accomplish complex coronary interventions
`with a wide variety of guiding catheters. The use of the GuideLiner as a
`support catheter that can be placed into the target vessel helps
`facilitate equipment delivery in challenging coronary lesions and can
`assist with engagement of the coronary ostium. Takahashi et al.
`demonstrated that a guide catheter extension system can provide
`substantial improvement in back-up support for complex coronary
`interventions, including TRI [19]. Some of the cases required deep
`vessel intubation with the GuideLiner (Fig. 3). In most cases, the
`GuideLiner was simply advanced over the coronary guidewire or an
`
`Fig. 4. Example of Guideliner Use for Proximal Lesion Tortuosity. (A) Long mid RCA lesion(White Arrow/Black Border) with proximal vessel “Shepherd’s Crook” severe tortuosity. (B)
`GuideLiner distal tip (Dashed Black Arrow) can be seen at the ostium of the RCA with guide catheter (White Arrow) disengaged from coronary artery resting along the contralateral
`aortic wall. (C) RCA status post deployment of 3.0 × 30 mm DES (Black Arrows).
`
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`
`In some cases, deeper intubation was
`un-inflated balloon shaft.
`accomplished by inflating a balloon distally as an anchor, and
`advancing the GuideLiner over the inflated balloon shaft. In other
`cases, the GuideLiner provided increased support with minimal
`vessel
`intubation, because advancing the GuideLiner caused the
`guide to back out until it rested on contralateral aortic wall (so-
`called Swan-neck maneuver) (Fig. 4) [20]. In our study, the mean
`intubation depth of the GuideLiner catheter was fairly modest at
`23 mm, highlighting the fact the many cases do not require deep
`intubation for procedural success.
`This study reports the largest published number of transradial
`GuideLiner interventions and sought to identify the variables that
`were associated with the use of the GuideLiner support catheter.
`Demographics and clinical characteristics of the study population
`were similar in both groups. However, the lesions in the GuideLiner
`group were significantly more complex, more calcified, and tended to
`be longer. The most striking difference between groups was the angle
`of the proximal vessel and lesion angle. Severe proximal coronary
`angulations (e.g., shepherd’s crook-shaped proximal RCA) (Fig. 4)
`pose an increased challenge for equipment delivery [21]. This study
`demonstrates the effectiveness of guide catheter extension in
`overcoming significant coronary vessel tortuosity as noted by a
`100% success rate in TRI with use of the GuideLiner and no conversion
`to femoral access. This study also demonstrates the multiple methods
`in which the GuideLiner can be used for increase guide support.
`Despite the aggressive use of the GuideLiner in certain cases, there
`were no major complications as seen in previous studies [22–24]. In
`fact, there were a significant number of coronary vessel dissections in
`the no GuideLiner group. This higher than expected rate of coronary
`dissections may have been related to deep guide catheter intubation
`in an effort to achieve better guide support. These findings may
`support earlier use of a Guideliner cather in cases where device
`delivery may otherwise necessitate guide manipulation with an
`associated risk of vessel injury.
`
`5. Conclusion
`
`The purpose of this study was to describe the angiographic
`variables that predicted the use of the GuideLiner catheter during
`TRI at an institution with an emerging transradial program. The
`GuideLiner allowed successful completion of TRI with a wide
`spectrum of guiding catheters including a large number of JL and
`JR standard TF catheters. Radial specific guide catheters could have
`been used in many of these cases, thereby possibly reducing the
`need for GuideLiner use. However,
`this retrospective review
`represents the practice patterns of novice transradial operators,
`who may preferentially use familiar guide catheters. Thus, the
`GuideLiner support catheter can serve as a useful tool for difficult
`PCI as operators refine their skills at transradial intervention. TRIs
`facilitated by the GuideLiner catheter had significantly more lesion
`complexity including proximal vessel and lesion tortuosity, lesion
`calcification, and lesion length. After multivaraible analysis, only
`proximal vessel angulation was found to be a significant determi-
`nant of need for GuideLiner support. Such information could help
`the transradial interventionalist better recognize the features of a
`challenging case. By doing so, physician utilization of a Guideliner
`
`catheter “up front” for certain TRIs could reduce use of resources
`including contrast use, and total fluoroscopy time.
`
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