Sheathless Guide Catheter Coronary Intervention Via Radial Artery: Single-Center Experience With 9658 Procedures

Abstract: Objectives. To evaluate the efficacy and safety of transradial coronary intervention (TRI) using a sheathless guide catheter (sheathless TRI) in a large, retrospective, single-center study. Background. The sheathless guide catheter was designed to be inserted without an introducer sheath to decrease stress to the radial artery. Although the sheathless guide catheter has some potential limitations, such as its procedural complexity or the risk of coronary ostial dissection, no large studies have been reported. Methods. We retrospectively investigated all TRIs performed at Sendai Kousei Hospital from January 2004 to December 2013. Results. Out of a total of 12,617 percutaneous coronary interventions (PCIs), sheathless TRIs were performed in 9658 cases (76.5%) and TRIs using a conventional sheath (sheath TRI) were performed in 1070 cases (8.5%). Procedural success was achieved in 98.81% of sheathless TRIs and 96.82% of sheath TRIs (P<.001); after propensity matching, the success rate was 98.9% in sheathless TRIs and 97.6% in sheath TRIs (P=.01). The conversion of the guide catheter system occurred in 0.40% of sheathless TRIs and 0.28% in sheath TRIs (P=.54). Coronary ostial dissection occurred in 0.26% of sheathless TRIs and 0.47% in sheath TRIs (P=.22). Conclusion. Sheathless TRI was utilized in the majority of cases, and the propensity-matched procedural success was similar but statistically higher as compared with sheath TRI. Complications were rare and equivalent to sheath TRI. Sheathless TRI is effective and safe as an initial PCI technique after the consideration of its benefits and limitations.

J INVASIVE CARDIOL 2015;27(5):237-241

Key words: sheathless guide catheter, transradial approach, percutaneous coronary intervention

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During percutaneous coronary intervention (PCI), the selection of the approach site is important because it affects the choice of guide catheter, the risk of vascular complications, and the level of patient discomfort. The transradial approach has been associated with reduced 30-day and 1-year mortality rates through a reduction in bleeding and need for transfusion as compared with the femoral approach.¹ However, transradial coronary intervention (TRI) using a conventional sheath has a limitation because the lumen size of the radial artery is sometimes too small for a sheath and a guide catheter to be inserted.² A sheathless guide catheter may overcome this limitation by eliminating the need for an introducer sheath and the use of hydrophilic coating. However, some disadvantages have been discussed in association with a sheathless guide catheter, such as less back-up force due to the slippage of the hydrophilic-coated catheter, the risk of coronary ostial dissection due to its stiff tip, and the procedural complexity of inserting or exchanging the sheathless guide catheter. 

Currently, only the results of small studies or case reports have been reported.^3-5 To validate the efficacy and safety of TRI using a sheathless guide catheter (sheathless TRI) in a study with a large number of subjects, we investigated all TRI procedures, including elective and emergent cases, performed in Sendai Kousei Hospital from 2004 to 2013; the procedural characteristics, procedural successes, and complications were analyzed and compared between sheathless TRI and TRI using a conventional sheath (sheath TRI). 

Methods

Patients. A total of 12,617 percutaneous coronary interventions (PCIs) that were performed at Sendai Kousei Hospital, Japan, from January 2004 to December 2013 were analyzed retrospectively. A total of 10,728 of these procedures were TRIs, and we compared the characteristics of sheathless TRI and sheath TRI. Procedural success was defined as successful revascularization without conversion to other guide catheter systems. Informed consent was obtained in all PCIs from the patients or their families. We used 1:4 propensity-score matching to assemble a cohort in which patients who received sheathless TRI and sheath TRI would be balanced on the basis of their baseline characteristics. Each patient in the sheath TRI group was matched by age, gender, acute coronary syndrome (ACS), chronic total occlusion (CTO), hypertension, hyperlipidemia, diabetes mellitus, and current smoking to 4 patients in the sheathless TRI group.

Sheathless guide catheter. The sheathless guiding catheter system (Asahi Intecc) does not require an introducer sheath to insert the catheter. It is available in 6.5 Fr, 7.5 Fr, and 8.5 Fr sizes. The 6.5 Fr sheathless catheters have a smaller outer diameter (2.16 mm) than a 5 Fr sheath introducer (2.29 mm), and the 7.5 Fr sheathless catheters have a smaller outer diameter (2.49 mm) than a 6 Fr sheath introducer (2.62 mm). The outer diameter of an 8.5 Fr sheathless catheter is 2.80 mm.

Transradial procedure using sheathless guide catheter. In patients who were hemodynamically stable, two puffs of a nitroglycerin spray were placed under the patient’s tongue immediately before local anesthesia was administered beneath the skin over the pulse of a radial artery. The radial artery was punctured with an 18 G venous needle and a 4 Fr conventional sheath was introduced using the Seldinger technique. Thereafter, the 4 Fr sheath was exchanged over a J-tipped 0.035˝ wire for a sheathless guide catheter connected with a supplied central dilator. When the catheter had reached the proximal ascending aorta, the central dilator was removed. The catheter was then advanced to achieve coronary intubation. During the procedure, a silicon-based stopper device was connected to the proximal end of the sheathless guide catheter and fixed to a surgical drape with forceps to avoid slippage (Figure 1). When the sheathless guide catheter needed to be exchanged, the catheter was straightened with the supplied dilator over the J-tipped 0.035˝ wire and was exchanged with a new guide catheter. At the end of the case, the catheter was removed over the J-tipped wire and a central dilator. The puncture site was sealed using a compression device (Tometa Kun). 

Statistical analysis. The data were presented as means ± standard deviation. Normally distributed continuous variables were compared using Student’s t-test and categorical variables were compared with the Pearson’s chi-square test. P-values <.05 were considered statistically significant. JMP 11 for Mac software and SAS version 9.3 for Windows (SAS Institute, Inc) were used for analyses. 

Results

A total of 12,617 PCIs were performed at Sendai Kousei Hospital between January 2004 and December 2013. Figure 2 shows the breakdown and chronological change in the different procedural approaches. In total, sheathless TRI was performed in 9658 cases (76.5%), sheath TRI was performed in 1070 cases (8.5%), the transfemoral approach (TFI) was used in 1776 cases (14.1%), and the transbrachial approach (TBI) was used in 113 cases (0.9%). According to chronological change, sheathless TRI increased from 2004-2005 to 2006-2007 and was kept stable thereafter. Sheath TRI decreased with time. Both types of TRI procedure were performed by 43 interventional cardiologists with experience levels varying from 1 year with supervision to “expert.” 

The clinical characteristics of the patients who received sheathless TRI and sheath TRI are shown in Table 1. Although the numbers of ACS and CTO cases were greater in the sheathless TRI group, their ratios were significantly larger in the sheath TRI group.

Procedural characteristics are summarized in Table 2. There were more complex lesions in the sheath TRI group (B2/C lesion: 74.3% in sheathless TRIs and 87.0% in sheath TRIs; P<.001). There were more multivessel PCIs in the sheath TRI group (5.2% in sheathless TRIs and 7.5% in sheath TRIs; P=.01). There were more cases that were completed using one guide catheter per vessel in the sheathless TRI group (93.1% in sheathless TRIs and 88.6% in sheath TRIs; P<.001). There were more cases that used a 6.5 Fr or 6 Fr guide catheter in the sheath TRI group (76.4% in sheathless TRIs and 87.7% in sheath TRIs; P<.001). In the sheathless TRI group, 22.6% were treated using a 7.5 Fr guide catheter. 

The procedural results are summarized in Table 3. Procedural success was achieved in 98.81% of the sheathless TRIs and in 96.82% of the sheath TRIs (P<.001). When the clinical baseline characteristics were propensity matched, procedural success was 98.89% for the sheathless TRIs and was 97.56% for the sheath TRIs (P=.01) (Table 4). Conversions of the guide catheter system, such as sheathless TRI to sheath TRI, sheath TRI to sheathless TRI, and TRI to another approach site, were necessary in 0.40% of the sheathless TRIs and in 0.28% of the sheath TRIs (P=.54). Ostial dissection due to manipulation of the guide catheter occurred in 0.26% of sheathless TRIs and in 0.47% of sheath TRIs (P=.22).

Discussion

The main findings of this large, retrospective single-center study were as follows: sheathless TRI was utilized in the majority of cases, the propensity-matched procedural success rate was similar but statistically higher as compared with sheath TRIs, and the complication rates were low and equivalent to sheath TRIs. 

The sheathless guide catheter. In order to perform PCI without the use of a sheath, the sheathless guide catheter was developed with three main characteristics. This first is the hydrophilic coating, which minimizes the stress to the skin and artery. Hydrophilic coatings have been shown to reduce discomfort and retrieval force when applied to radial sheaths.⁶ Although TRI procedures that use a conventional sheath have been associated with small risk of radial artery spasm,^7,8 the need for the conversion of the guide catheter system in sheathless TRI due to radial artery spasm was found in only 1 case in our study.  

The second characteristic of the sheathless guide catheter is a strong shape memory. To insert the guide catheter without an introducer sheath, the sheathless guide catheter must be straightened with a supplied dilator. Therefore, a stronger shape memory is required for successful use. During the early phase of this study, ie, from 2004-2007, engaging a sheathless guide catheter into the coronary artery was sometimes difficult even though several different shapes of a catheter were tried. Twenty-one sheathless TRI cases required conversion of the guide catheter system because the catheter was impossible to engage; however, most of them occurred in the early phases of the study. After several modifications of the catheter shape, we now rarely encounter difficulties engaging coronary arteries using the standard line-up. 

The third characteristic of the sheathless guide catheter is  tip stiffness. To braid the skin and the radial artery, a sheathless guide catheter would require a stiffer tip than a conventional guide catheter. This stiff tip has been discussed as a risk for coronary ostium injury.^3-5 Ostial dissection by a guide catheter sometimes can induce the sudden occlusion of coronary flow, which can result in catastrophic complications and require bail-out stent deployment. Previous studies have reported no cases of ostial dissection induced by a sheathless TRI because of the small number of data samples.^3,5 To the best of our knowledge, this is the first study to report the risk of coronary ostial dissection in sheathless TRI; the incidence was extremely low, with no significant difference as compared with sheath TRI.

How to avoid ostial injury with a sheathless guide catheter. Due to the tip stiffness of a sheathless guide catheter, operators should always consider the risk of ostial injury during PCI. The most important thing to ensure is that a guide catheter should be coaxial to a coronary artery. When an ostial injury occurs, the tip of a sheathless guide catheter is always not coaxial and sticks to the coronary artery. Furthermore, ostial injury occurs most often at the time of contrast injection. Operators should take special care of the angle between the tip of the catheter and a coronary artery in contrast injection. Mechanical injection is a risk because it produces a steep rise in contrast injection speed. A side hole would be a solution because it decreases a force to the coronary artery in contrast injection.⁹

Case selection. We believe that the less invasive sheathless TRI can be applied as an initial technique if the transradial approach is utilized. However, sheathless TRI should not be indicated for all PCIs; therefore, case selection is essential. We have to consider the benefits and limitations. Sheathless TRI also requires a learning curve. We recommend extending its indications through a process of step-by-step experience.

Beginners should start with relatively simple cases such as an elective cases that would not require a strong back-up or special devices, and that have a standard coronary take-off. The next step would be utilization during cases that required more back-up, and ACS. 

Sheathless TRI is associated with less back-up force and guide catheters can easily slip due to the hydrophilic coating. A rubber stopper is one way to prevent this occurrence (Figure 1). If a stronger back-up is essential, deep engagement is a solution. However, we should take extra care against coronary injury (as stated above). A 7.5 Fr sheathless TRI that has an outer diameter smaller than that of a 6 Fr sheath introducer also offers stronger back-up. The 7.5 Fr sheathless TRI is also feasible when using special techniques such as simultaneous kissing stents⁴ or rotational atherectomy using a burr >1.75 mm in size. 

Once the operator becomes accustomed to the fundamental maneuvers of the sheathless TRI, we strongly recommend challenging ACS. In treating ACS, anticoagulant therapy is required during and after PCI. Bleeding is a significant predictor of morbidity and mortality.¹⁰ Jolly et al reported that TRI showed a lower incidence of major vascular complications in ACS.¹¹ Sheathless TRI may have less bleeding risk than sheath TRI for ACS because of the smaller size of the outer diameter. Furthermore, we believe that the 7.5 Fr sheathless TRI procedures could be beneficial for cases with thrombus-rich ACS because larger thrombectomy devices present greater aspiration.¹²

Eventually, sheathless TRI can be applied to more complex cases, including those that require special devices like rotational atherectomy or distal protection devices, unprotected left main trunk, bifurcations, or cases requiring strong back-up such as heavily calcified or tortuous lesions.

Nevertheless, we do not recommend the selection of a sheathless TRI procedure for cases with extremely abnormal coronary take-off or CTO. Cases with extremely abnormal coronary take-offs may require several guide catheter exchanges, and this procedure may involve some complexity and a small amount of bleeding. We recommend sheath TRI for these cases.

At our institution, we do not select a sheathless TRI for CTO cases because it would require significant back-up support and could be a very complex procedure; furthermore, it often increases the length of a procedure that has a risk of radial artery spasm. Therefore, we basically recommend transfemoral intervention for CTO. However, some cases with short occlusion length and procedure duration have been treated with sheathless TRI. 

TRI is basically contraindicated for hemodialysis patients, subclavian artery occlusions, and for patients with positive Allen’s test.

Study limitations. There were several limitations in our study. One was the study design, which was a retrospective analysis of a single center. Because our hospital is a highly experienced sheathless TRI center, this result may not apply to standard operators or institutions. The second limitation was that the comparisons between sheathless TRI and sheath TRI were not randomized. The third limitation was the insufficient data for radial occlusion. We typically assessed the radial pulse after the procedure; however, depending on the clinical circumstances, we did not assess the radial pulse in some cases due to death or compromised hemodynamics. Critical arm ischemia requiring amputation or resulting in persistent paralysis was not observed in any case. The other limitation was the lack of sample uniformity; this included sheathless guide catheter procedure repeats with minor modifications, such as shape memory or tip stiffness, over the course of one decade in this study period. This fact influenced our procedural strategy because in the early phases, sheathless guide catheters may be difficult to engage in some coronary arteries; therefore, we had selected the sheath TRI as the initial system for ACS in those cases.

Conclusion

In this large, retrospective single-center study, sheathless transradial intervention is effective and safe as an initial PCI technique in both elective and emergent situations. However, sheathless transradial intervention is not indicated for all PCIs; therefore, case selection is crucial after consideration of the benefits and limitations.

References

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From the ¹Department of Cardiology, Sendai Kousei Hospital, Sendai, Japan; and ²Department of Biostatistics and Epidemiology, Yokohama City University, Yokohama, Japan.

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 submitted April 7, 2014, provisional acceptance given May 12, 2014, final version accepted August 18, 2014.

Address for correspondence: Norio Tada, Department of Cardiology, Sendai Kousei Hospital, 4-15 Hirosemachi Aoba Sendai, Miyagi 980-0873, Japan. Email: noriotada@hotmail.com