Abstract
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 < 0.001). Lesion angle in the Guideliner group was also significantly greater (48° ± 32° vs. 28° ± 25°, p < 0.001). On multivariable analysis, proximal vessel angle independently predicted the need for GuideLiner support (AOR 1.4 per 10°, p < 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.
1
Introduction
Transradial coronary intervention (TRI) is associated with significantly reduced rates of bleeding and access site related complications compared to the transfemoral (TF) approach. Although TRI is increasingly common, it currently represents < 10% of all PCIs in the USA. Barriers to TRI include a steep initial learning curve and time required to gain proficiency at TRI . Additionally, anatomic variations and lack of guide catheter support increase the technical complexity of TRI .
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 . 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 . More aggressive radial-specific guides can also be used, but these may also result in proximal vessel injury. With many new operators adopting radial catheterization 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 . 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 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 intervention. The following procedural characteristics were assessed: access site, target vessel, ACC/AHA lesion type (A, B1, B2, C) , size of the guide catheter, types of balloons/stents delivered, and procedural success. Procedural success was defined as final target lesion stenosis of < 20% 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 (< 45°), moderate (45°–90°), or excessive (> 90°) . 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 experienced 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 univariate analysis using a cutoff of p < 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.
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 intervention. The following procedural characteristics were assessed: access site, target vessel, ACC/AHA lesion type (A, B1, B2, C) , size of the guide catheter, types of balloons/stents delivered, and procedural success. Procedural success was defined as final target lesion stenosis of < 20% 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 (< 45°), moderate (45°–90°), or excessive (> 90°) . 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 experienced 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 univariate analysis using a cutoff of p < 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 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 GuideLiner 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.
| Variable | GuideLiner (N = 22) | No GuideLiner (N = 124) | P value |
|---|---|---|---|
| Male (%) | 15 (68) | 95 (77) | 0.4 |
| Age, years | 69 ± 12 | 62 ± 13 | 0.03 |
| Indication | 0.6 | ||
| Elective | 10 (45) | 49 (40) | |
| ACS | 12 (55) | 75 (60) | |
| Hypertension (%) | 17 (77) | 95 (77) | 0.9 |
| Hyperlipidemia (%) | 16 (73) | 66 (53) | 0.09 |
| Diabetes (%) | 11 (50) | 47 (38) | 0.3 |
| Active smoker (%) | 2 (9) | 28 (23) | 0.1 |
| Family history of CAD | 1 (5) | 7 (6) | 0.8 |
| Prior MI | 2 (9) | 12 (10) | 0.9 |
| Prior PCI | 6 (27) | 25 (20) | 0.5 |
| Prior CABG | 6 (27) | 21 (17) | 0.3 |
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 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 < 0.001). Lesion angle was significantly greater among patients that required GuideLiner support (48° ± 32° vs. 28° ± 25°, p < 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.
