The Efficacy and Feasibility of Chronic Total Occlusion by Transradial Intervention: A Japanese Single-Center Retrospective Study

Abstract: Objectives. To evaluate transradial intervention (TRI) for chronic total occlusion (CTO). Background. Although TRI has been applied to more complex lesions in percutaneous coronary intervention, efficacy and feasibility of TRI versus transfemoral intervention (TFI) for CTO have not yet been determined. Methods. We retrospectively analyzed 207 CTO lesions in 195 patients in a single center between January 2008 and December 2011. Patients were divided into four groups according to procedures: TRI (135 lesions in 124 patients); TFI (40 lesions in 39 patients); TRI/TFI (20 lesions in 20 patients); and TFI/TFI (12 lesions in 12 patients). Antegrade approach was used in TRI and TFI, but antegrade plus retrograde approach was used in TRI/TFI and TFI/TFI. Results. Although there were no differences in patient characteristics, complex CTO lesions such as blunt-type entry and retry lesions were frequently observed in the TFI/TFI group. Average sheath size was 5.7 Fr for TRI and 6.6 Fr for TFI. Fluoroscopy time was significantly longer for the antegrade plus retrograde approach. Procedure success rates were not statistically different: 82.2% in TRI, 72.5% in TFI, 75.0% in TRI/TFI, and 75.0% in TFI/TFI groups. There was no death, myocardial infarction, or stroke at 30 days in any groups. Two femoral cases and no radial cases had access-site complications. Access-site crossover from radial to femoral was conducted in 4 cases. Conclusion. More than one-half of CTO lesions can be treated with high success and low complication rates by TRI if the lesions are carefully selected. 

J INVASIVE CARDIOL 2015;27(9):E177-E181

Key words: transradial intervention, transfemoral intervention, chronic total occlusion

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Transradial intervention (TRI) has been applied to emergency cases such as ST-elevation myocardial infarction and acute coronary syndrome in percutaneous coronary intervention (PCI).^1,2 However, chronic total occlusion (CTO) has not been considered an ideal target for transradial approach because CTO procedures need larger guiding catheters for strong back-up force and complex device usage.^3,4 The aim of this study was to evaluate efficacy and feasibility of TRI for treatment of CTO.

Methods

Population. A total of 215 consecutive PCI procedures performed for CTO lesions in 203 patients were retrospectively reviewed and analyzed according to the approach site at our center from January 2008 to December 2011 (48 months).

Definitions. Chronic total occlusion was defined as an occlusion on angiography with no antegrade filling of the distal vessel other than via collaterals. The duration of the occlusion had to be >30 days, estimated from onset of clinical events such as myocardial infarction, sudden onset or worsening of chest symptoms, or proven by angiography. If the duration of the occlusion was uncertain, but the investigators had no clear reason to date the onset of the lesion at <30 days, the occlusion was considered to be a CTO.⁵ 

Approach site. We divided the patients into five groups according to the approach site. An antegrade approach was used in TRI and transfemoral intervention (TFI) and an antegrade plus retrograde approach was used in TRI/TFI, TFI/TFI, and TRI/TRI. Since the biradial approach (TRI/TRI) was not performed in any case during this period, further analysis was performed in only four groups upon exclusion of the TRI/TRI group. Transbrachial approach was performed in 8 CTO cases during this period, but were excluded from this study. When two sheaths were inserted, but only the retrograde catheter was used for diagnosis, it was considered to be an antegrade approach.

Endpoints. Our primary endpoint was procedure success rate, which was defined as percentage of diameter stenosis <50% with TIMI-3 flow by angiography. Secondary endpoints were major adverse cardiac and cerebrovascular event (MACCE) during hospital stay and procedure-related complications. MACCE was defined as cardiac death, index lesion myocardial infarction (non-procedure related), stroke, or target-lesion revascularization. Procedure-related complications included those involving the coronary artery and access site.

J-CTO score. J-CTO score⁶ was measured according to the angiographic definitions of each variable including blunt type, presence of calcification, presence of bending >45, occlusion length >20 mm, and retry lesions. Each variable was taken as one point, so the score was calculated from 0-5: easy (0), intermediate (1), difficult (2), and very difficult (≥3).

Statistical analysis. Data are expressed as mean ± standard deviation. Analysis of variance test was performed to compare the numerical parameters between the four groups. All statistical calculations were performed using JMP version 10 (SAS Institute, Inc). A P-value <.05 was considered significant and analysis was by intention to treat.

Results

Patient characteristics. A total of 207 CTO lesions in 195 patients were collected: (1) TRI group, 135 lesions in 124 patients; (2) TFI group, 40 lesions in 39 patients; (3) TRI/TFI group, 20 lesions in 20 patients; and (4) TFI/TFI group, 12 lesions in 12 patients. Mean age was 66.5 ± 10.8 years, and 84.1% of patients were male. Patient characteristics are shown in Table 1. There were no differences in age, gender, coronary risk factors (smoking history, diabetes mellitus, dyslipidemia, hypertension, and family history) or histories of myocardial infarction, coronary bypass grafting, PCI, and congestive heart failure. Hemodialysis patients were common in the TFI and TFI/TFI groups because radial access was considered as a contraindication due to arteriovenous shunt of the forearm. 

CTO target lesions and characteristics. CTO target lesions and site characteristics are shown in Table 2. Target lesions were left main (1.4%), left anterior descending (32.9%), left circumflex (20.3%), and right coronary artery (45.4%). There were no differences in CTO target lesions among the four groups. CTO characteristics showed that blunt-type entry was less frequent in the TRI group and more frequent in the TFI/TFI group. Retry lesions were frequently observed in the TFI/TFI group. Mean J-CTO scores were lower in the TRI group and higher in the TFI/TFI group.

Success rates. Overall success rate was 79.2%, and CTO success rate in each group is shown in Figure 1. There was no significant difference in success rate among the four groups. Success rate according to J-CTO score in comparison between TRI and TFI groups is shown in Figure 2. Antegrade approach was performed in 135 TRIs and 40 TFIs. Success rates were not significantly different in any J-CTO score group.

Procedure characteristics. Procedure characteristics are shown in Table 3. Fluoroscopy time was longer using the antegrade plus retrograde approach (TRI/TFI and TFI/TFI groups) than the antegrade approach (TRI and TFI groups). There was no difference in contrast medium volume among the four groups. There were no significant differences in fluoroscopy time for low J-CTO score (0-2) cases between TRI and TFI (51.7 ± 36.5 min vs 66.0 ± 36.3 min; P=.10) or for high J-CTO score (3-4) cases (62.0 ± 29.7 min vs 60.2 ± 30.8 min; P=.87). In addition, there were no differences in contrast medium amount for low J-CTO score (0-2) cases between TRI and TFI (249 ± 107 mL vs 257±127 mL; P=.79) or for high J-CTO score (3-4) cases (315 ± 150 mL vs 248 ± 99 mL; P=.08). Eight cases (3.9%) were complicated by coronary perforation. In the TRI/TFI group, 2 septal channel perforations were documented using the retrograde approach. A total of 6 coronary perforations occurred as a result of the antegrade approach. All cases were successfully treated with fat embolization, negative pressure using a microcatheter, or long balloon inflation. No cardiac tamponade was reported. In 1 case in the TRI/TFI group, major bleeding was a complication at the femoral access site and required blood transfusion as well as vascular repair surgery. No MACCE, including cardiac death, index lesion myocardial infarction (non-procedure related), stroke, or target lesion revascularization, was observed within 30 days of the procedures. 

Eight cases required a change in approach site or larger catheters (Table 4). Crossover of the approach site from radial to femoral occurred in 4/155 cases (2.6%) because of the need for a larger guiding catheter and tortuosity of the subclavian artery, but no crossover occurred from femoral to radial site. Requirement for a larger-sized guiding catheter was observed in 2 radial cases and 2 femoral cases.

Catheter selection and size. Catheter size in each group is shown in Figure 3. Average catheter size was 6 Fr or less in the TRI group. Guiding catheter selection is shown in Figure 4. The Ikari L was mainly used, especially for the right coronary artery.

Discussion

In this study, a total of 135/207 CTO lesions (65.2%) were treated by TRI, and 82.2% success rate was achieved without any MACCE at 30 days. Access-site crossover from radial to femoral was observed in 4/155 cases (2.6%). Published data regarding TRI for CTO have been limited. Rathore et al reported similar angiographic success rates as TRI for CTO (82% in the radial group vs 86% in the femoral group), and access-site vascular complications were significantly less in the radial group undergoing a CTO procedure.⁷ Liu et al reported that the success rate of TRI for CTO was 80% without access-site complications.⁸ Both reports mentioned only the antegrade approach. In this study, the success rate of TRI using an antegrade approach was 82.2% without any complications, which was comparable to prior reports. Progress in improving the retrograde approach has increased the success rate of CTO;^9-11 in this study, the retrograde approach was performed in 32 cases (15.5%), and the success rate was 75.0% (24/32 cases). Performance of the antegrade and retrograde approach has been increasing rapidly every year. 

Blunt-type entry at the CTO lesion has been considered a cause of unsuccessful PCI for CTO lesions.^6,12 In this study, TFI with antegrade or antegrade plus retrograde approach was mainly performed for blunt-type entry in CTO lesions because large guiding catheters could then be used, thus facilitating techniques such as parallel wiring and intravascular ultrasound guided wiring. On the other hand, the J-CTO score was sequentially increasing from TRI, TFI, TRI/TFI to TFI/TFI, although the success rates were not significantly different among the four groups according to approach site. The operators carefully selected the approach site based on CTO difficulty. These data suggested that we can perform TRI for CTO if we carefully choose appropriate lesions. In particular, a low J-CTO score may be one of the favorable factors in TRI. Given the progress of transradial techniques,^13,14 TRI for CTO may increase in the future.

The PIKACHU registry reported an 87.9% success rate for CTO lesions with low complication rates achieved by the radial approach (76.6%), and that a sheath size of 6 Fr or less was frequently used (85.8%).¹⁵ Other previous reports mentioned that a lower rate of local vascular complications including bleeding and ischemic events may be a reason to use the radial approach.^2,16 In this study, there were 155 radial artery punctures performed during transradial approach (135 TRI and 20 TRI/TFI) and 84 femoral artery punctures performed during transfemoral approach (40 TFI, 20 TRI/TFI, and 24 TFI/TFI). We defined vascular complications as serious problems that required transfusion and operation, thus, we confirmed 0 vascular complications in transradial punctures and 2 (2.4%) in transfemoral punctures. 

Study limitations. This was a retrospective, observational, and non-randomized study that included a small number of patients collected at a single institution. Selection bias could be excluded because we carefully selected the approach site for each case based on patient and coronary lesion complexity.

Conclusion

TRI for CTO lesions may be feasible in selected cases, and results in low complication rates and low crossover rates.

References

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From the Department of Cardiology, Tokai University School of Medicine, Isehara, Kanagawa, Japan.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Ikari reports grant and personal fees from Terumo Corporation. The remaining authors report no disclosures regarding the content herein.

Manuscript submitted September 16, 2014, provisional acceptance given October 23, 2014, final version accepted January 26, 2015.

Address for correspondence: Yuji Ikari, MD, PhD, Department of Cardiology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan. Email: ikari@is.icc.u-tokai.ac.jp