Abstract: Background. The use of saphenous vein grafts (SVGs) for retrograde native-vessel chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has received limited study. Methods. We retrospectively reviewed the medical records and coronary angiograms of retrograde CTO-PCI performed through an SVG at four United States institutions between 2012 and 2013. Results. During the study period, retrograde CTO-PCI was performed in 144 of 572 cases (25.2%) and retrograde CTO-PCI via SVG in 21 patients (14.6% of all retrograde cases). Mean age was 71 ± 7 years and 95.2% of the patients were men. The CTO target vessel was the right coronary (38%), circumflex (38%), and left anterior descending (24%) artery. Mean J-CTO score was 3.5 ± 1.0. The most common reentry technique was reverse controlled antegrade dissection and reentry. Technical and procedural success rates were 86% and 81%, respectively, with retrograde SVG-PCI attempts being successful in 67%. A major adverse cardiac event occurred in 2 patients (1 periprocedural myocardial infarction and 1 tamponade resulting in death). Median contrast volume, fluoroscopy time, and procedure time were 250 mL, 91.6 minutes, and 214 minutes, respectively. Two SVGs were coiled due to competitive flow after CTO recanalization. Conclusion. Retrograde native-vessel CTO-PCI via SVG represents a small proportion of retrograde CTO-PCIs and was associated with high technical success rates, but may carry increased risk for complications.
J INVASIVE CARDIOL 2016;28(6):218-224
Key words: chronic total occlusion, percutaneous coronary intervention, saphenous vein graft
The retrograde approach to chronic total occlusion (CTO) percutaneous coronary interventions (PCI) has significantly improved procedural success rates.1-7 The most common retrograde conduits are septal collaterals followed by epicardial collaterals. Patent or occluded saphenous vein grafts (SVGs) can also be used for retrograde access in prior coronary artery bypass graft (CABG) surgery patients; however, their use in this setting has received limited study.8-13 We retrospectively examined native-vessel CTO-PCI in post-CABG patients, which included a retrograde attempt through an SVG to determine the procedural and technical characteristics and associated outcomes.
We reviewed the clinical and angiographic records of consecutive patients who were included in the Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS CTO; NCT02061436)14-21 and underwent retrograde CTO-PCI via SVG during 2012 and 2013 at four United States institutions with significant expertise in CTO-PCI: Appleton Cardiology (Appleton, Wisconsin), Mid America Heart Institute (Kansas City, Missouri), Piedmont Heart Institute (Atlanta, Georgia), and VA North Texas Health Care System (Dallas, Texas). The study was approved by the institutional review board of each center.
Definitions. Coronary CTOs were defined as coronary lesions with Thrombolysis in Myocardial Infarction (TIMI) grade 0 flow of at least 3-month duration. Estimation of the occlusion duration was based on first onset of anginal symptoms, prior history of myocardial infarction (MI) in the target-vessel territory, or comparison with a prior angiogram. The J-CTO score was calculated as described by Morino et al.22
Technical success of CTO-PCI was defined as successful CTO revascularization with achievement of <30% residual diameter stenosis within the treated segment and restoration of antegrade TIMI grade 3 flow. Procedural success was defined as achievement of technical success with no in-hospital major adverse cardiac event (MACE). MACE included any of the following adverse events prior to hospital discharge: death from any cause, Q-wave MI, recurrent symptoms requiring urgent repeat target-vessel revascularization with PCI or CABG surgery, tamponade requiring either pericardiocentesis or surgery, and stroke.
Statistical analysis. Continuous data were summarized as mean ± standard deviation (normally distributed data) or median and interquartile range (IQR; non-normally distributed data) and compared using t-test or Wilcoxon rank-sum test, as appropriate. Categorical data were presented as frequencies or percentages and compared using Chi-square or Fisher’s exact test, as appropriate. A P-value of <.05 was considered statistically significant. Statistical analyses were performed using JMP version 11.0 and SAS version 9.2 (SAS Institute).
Clinical and angiographic characteristics. During the study period, retrograde CTO-PCI was performed in 144 of 572 cases (25.2%). Retrograde CTO-PCI via SVG was performed in 21 cases (14.6% of all retrograde cases). The baseline characteristics of the study population are shown in Table 1, while angiographic characteristics are shown in Table 2. Mean age was 70.8 ± 7.3 years and 95.2% of the patients were men, with a high prevalence of hyperlipidemia, hypertension, and smoking. The distribution of Canadian Cardiovascular Society (CCS) angina classification (available for 14 patients) was: class I (angina with strenuous activity) 7.2%; class II (angina with moderate exertion) 35.7%; and class 3 (angina with mild exertion) 57.1%. The CTO target vessel was the right coronary artery (38%), circumflex artery (38%), or left anterior descending (LAD) coronary artery (24%). Median CTO occlusion length was 38 mm (range, 30-60) and mean J-CTO score was 3.5 ± 1.0, suggesting that these occlusions were very challenging to recanalize.
The SVG used for retrograde CTO-PCI was anastomosed to the posterior descending artery in 10 cases, to an obtuse marginal branch in 6 cases, and to the LAD in 5 cases. The SVG was degenerated or had high-grade lesions in all cases, and was occluded in 1 patient. Bilateral arterial access was used in all cases as follows: 28.6% dual radial, 52.4% dual femoral, and 19% combined radial/femoral.
Crossing strategies. A primary retrograde approach was used in 52% of cases and after antegrade crossing failure in the remaining 48%. Several crossing strategies were often used in the same case, as follows: one strategy in 4 cases (19.1%); two strategies in 9 cases (42.9%); three strategies in 7 cases (33.3%); and four strategies in 1 case (4.8%).
Retrograde crossing success through the SVG was achieved in 14 cases (66.7%). The reasons for retrograde failure included inability to wire the SVG or collaterals (n = 5), reenter into the native vessel due to proximal side-branch occlusion (n = 1), cross the SVG anastomosis (n = 1), or externalize the retrograde wire (n = 1). In 3 procedures, the retrograde SVG wire served as a marker to guide antegrade crossing attempts (Figure 1).
Intravascular ultrasound was infrequently used (n = 2; 9.5%) to identify the proximal cap for antegrade crossing. The most common reentry technique in the successful retrograde SVG group was the reverse controlled antegrade and retrograde tracking and dissection (reverse CART) technique (in 64.3%). The Stingray reentry system was utilized in 4 cases (19.0%), but was only successful in 1 case using the “stick-and-swap” technique.
In 3 cases, two different SVGs were utilized during the same procedure to recanalize the native-vessel CTO. In the first case, a mid left circumflex artery CTO could not be opened with a retrograde attempt through an SVG-obtuse marginal (OM), antegrade wiring with intravascular ultrasound guidance, repeat retrograde SVG-OM wiring and unsuccessful puncturing into the prior left main stent, and retrograde left internal mammary artery (LIMA)-LAD attempt for wiring through an epicardial collateral. In the second case, retrograde attempts to cross a proximal LAD-CTO through an SVG to the right posterior descending artery failed due to inability to cross a septal collateral channel and through an SVG to diagonal due to inability to cross a proximal diagonal subtotal occlusion. The CTO was subsequently successfully crossed in the antegrade direction using a Crossboss catheter (Boston Scientific) that achieved true to true lumen crossing. In the third case, retrograde attempts to cross a proximal LCX-CTO through an SVG to the right posterior descending artery and an epicardial collateral and antegrade wiring failed. The occlusion was successfully recanalized retrogradely through an SVG-OM.
Support catheters and coronary guidewires. Overall, microcatheters were used in 95.2% of cases: 80% Corsair (Asahi Intecc); 15% Finecross (Terumo); and 5% Crossboss (Boston Scientific). A guide-catheter extension was used in 11 cases (52.4%), to facilitate balloon or stent delivery. Wires that successfully crossed the SVG included: 50% Pilot 200 (Abbott Vascular), 14.3% Confianza Pro 12 (Asahi Intecc), 14.3% Fielder XT (Asahi Intecc), 14.3% Runthrough (Terumo), and 7.1% Sion (Asahi Intecc). Retrograde wire externalization was performed in one-half of the successful retrograde cases through the SVG.
Location and mechanisms of side-branch loss. Side-branch loss occurred with similar frequency among successful and unsuccessful retrograde cases via an SVG (35.7% vs 14.3%; P=.61). In the successful group, the mechanism of side-branch loss was most commonly stenting over the side branch (n = 4; 80%) and retrograde dissection/reentry (n = 1; 20%); an (unsuccessful) attempt to recanalize the occluded side branch was performed in 1 case. In the failed group, 2 side branches were occluded, both due to retrograde dissection and reentry. Bifurcation stenting was done in only 1 LCX-CTO procedure with preservation of a large OM side branch using the mini-crush technique.
Other technical and procedural characteristics. The SVG that was used for retrograde CTO-PCI was coiled after completion of the procedure in 2 patients; in the first patient, an SVG to the OM branch was treated with 3 coils, and in the second patient, an SVG to the right posterolateral branch was treated with 2 coils (5 x 150 mm Interlock; Boston Scientific) (Figures 2 and 3).
Procedural outcomes and complications. The overall technical and procedural success rates were 85.7% and 81.0%, respectively. Technical success of recanalizing the native CTO was achieved in 92.9% of patients in whom retrograde SVG crossing was successful as compared with 71.4% of patients in whom retrograde SVG crossing failed (P=.25). Procedural success rates were 85.7% and 71.4%, respectively (P=.57).
Median contrast volume, procedure time, and fluoroscopy time were 250 mL (IQR, 200-400 mL), 214 minutes (IQR, 177-254 minutes), and 91.6 minutes (IQR, 58.9-106 minutes), respectively. Non-CTO lesions were treated in 42.9% of the patients; 5 patients underwent left main stenting, 3 patients underwent stenting of the right coronary artery and 1 patient underwent stenting of an OM branch.
Procedural complications occurred in 2 of 21 patients (10.0%). One patient experienced a periprocedural MI due to occlusion of a diagonal branch and another had a perforation that caused tamponade and cardiogenic shock resulting in death. Two other patients had coronary perforations, which were treated with placement of a covered stent in 1 patient and prolonged balloon inflation in the other patient, but neither required pericardiocentesis.
The main findings of our study are that retrograde PCI of native CTOs through an SVG can be achieved in most patients, but can be a technically demanding procedure that may be associated with increased risk for complications.
The retrograde approach is preferred as an initial strategy for CTOs with ostial or long occlusions (>20 mm), ambiguous proximal cap, severe tortuosity and calcification, and poor distal target-vessel quality, provided that adequate collaterals are present. As compared with septal and epicardial collaterals, bypass grafts are large, non-tortuous, easy to wire, and less likely to perforate.5 Retrograde wiring through the distal SVG anastomosis can be challenging, but can be facilitated by using a deflectable-tip microcatheter.23 In our study, the Venture deflectable-tip microcatheter (St. Jude Medical) was utilized in 2 cases: 1 unsuccessful antegrade attempt at engaging a LAD ostial CTO and 1 unsuccessful retrograde attempt through an SVG due to inability to navigate the distal SVG anastomosis.
In a single-center retrospective study from Japan, a total of 157 patients had retrograde CTO-PCI between 2003-2008, 75.2% of which had prior failed antegrade attempts, with the use of septal collaterals (67.5%), epicardial collaterals (24.8%), or SVGs (7.6%).6 Retrograde success was 65.6% and final procedural success was 85.7%, with the ability to cross the collateral channel being a major determinant of success. Our registry had a higher proportion of retrograde crossing via an SVG (14.6% of all retrograde cases), similar success of retrograde crossing through an SVG (66.7%), and similar procedural success rate (81.0%).
Challenges of retrograde CTO-PCI via SVG. Retrograde CTO-PCI via SVG can be associated with several challenges. First, equipment advancement through degenerated SVGs could cause distal embolization, although distal embolization was not observed in our series. Second, wiring proximal to the SVG distal anastomosis can be challenging due to severe angulation. Use of a deflectable-tip catheter can help in such cases.23 Third, retrograde crossing of a CTO in the left coronary system can result in injury of the left main coronary artery (whether retrograde crossing is achieved via an SVG or through a septal or epicardial collateral). Indeed, 5 of 11 patients with left-sided CTOs required left main stenting. Fourth, retrograde crossing succeeded in only approximately 2 of 3 cases; hence, strong antegrade crossing skills remain important for achieving high success rates. Fifth, retrograde PCI of native CTOs via SVGs may carry increased risk for complications: 3 perforations (14.3%) occurred in our series, 2 of which were successfully treated percutaneously, but 1 of which resulted in death. Perforation in prior CABG patients may be associated with higher risk than non-prior CABG patients due to localized compression and tamponade.24 Sixth, these procedures can be highly challenging, requiring long procedure and fluoroscopy times; hence, meticulous attention should be paid to optimizing radiation safety. Seventh, there remains controversy about the optimal treatment of an SVG after successful recanalization of the native coronary artery CTO. Some operators advocate routine coiling of such SVGs to minimize competitive flow, yet this was only performed in 2 cases in our series. Eighth, retrograde CTO-PCI can be achieved through chronically occluded SVGs, although only 1 such case was included in our series. In such cases, it is preferable to recanalize the native coronary artery CTO, as recanalizing SVG-CTOs has been associated with high restenosis and reocclusion rates.25
Long-term outcomes after CTO-PCI among prior CABG patients. In a single-center study from the Netherlands, a total of 24 patients with prior CABG and graft occlusion underwent CTO-PCI (11 native CTOs and 13 SVG-CTOs) with 100% technical success. Two patients in the SVG group had hemodynamic instability (1 required intraaortic balloon pump support and 1 required temporary pacing). Three-year event-free survival was similar in the two groups (81.8% for native vessels and 83.9% for SVGs).26
In another single-center study from Arkansas, a total of 28 SVG-CTOs underwent PCI, with 79% technical success and 10.7% procedural complication rate, including 2 Q-wave MIs and 1 contained SVG perforation.25 Improvement in CCS angina class at 30 days was observed in 90.4% of the successfully revascularized group vs 33% of the failed procedure group (P<.01). Unsuccessful CTO-PCI of an SVG was more likely in older grafts with longer estimated CTO duration.
In a third study from Italy, a total of 34 CTO-PCIs of an SVG were performed with 68% technical success rate and no in-hospital adverse events.27 The in-stent restenosis rate was 68% in the successful CTO-PCI group, 77% of which were focal. During a median follow-up of 18 months, the incidence of target-vessel revascularization was 61%.
Our study does not include long-term outcome data, but successful CTO-PCIs have been associated with lower cardiac mortality and need for CABG surgery as compared with failed procedures.28,29 However, restenosis and repeat revascularization continue to occur after CTO-PCI.30
Study limitations. Our study has important limitations. It was a retrospective study that included a relatively small number of patients, although to the best of our knowledge this is the first systematic study of its kind to be published. No core laboratory assessment or clinical events committee adjudication were performed, and long-term clinical outcomes were not available. The reported cases were performed by highly experienced operators and may not be generalizable to PCI centers and operators with less experience in CTO-PCI. Given the unique technical challenges and inherent risks of retrograde CTO-PCI via SVGs, such procedures should ideally be performed by high-volume, highly-skilled CTO operators and centers.
Retrograde recanalization of native CTOs via SVGs can be challenging to perform but can be successful in the majority of cases even though it may carry risk for complications.
Acknowledgment. Study data were collected and managed using research electronic data capture (REDCap) tools hosted at the University of Texas Southwestern Medical Center.31 REDCap is a secure, web-based application designed to support data capture for research studies, providing: (1) an intuitive interface for validated data entry; (2) audit trails for tracking data manipulation and export procedures; (3) automated export procedures for seamless data downloads to common statistical packages; and (4) procedures for importing data from external sources.
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From the 1VA North Texas Health Care System and University of Texas Southwestern Medical Center, Dallas, Texas; 2Henry Ford Hospital, Detroit, Michigan; 3Columbia University, New York, New York; 4University of Washington, Seattle, Washington; 5Mid America Heart Institute, Kansas City, Missouri; 6Piedmont Heart Institute, Atlanta, Georgia; and 7Boston Scientific, Natick, Massachusetts.
Funding: Research reported in this publication was supported by the National Center for Advancing Translational Sciences of the National Institutes of Health under award number UL1TR001105. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.
Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Alaswad reports consulting fees from Asahi Intecc, Boston Scientific, Abbott Vascular, and Terumo. Dr Karmpaliotis reports speaker’s bureau fees from Abbott Vascular, Boston Scientific, and Medtronic. Dr Lombardi reports equity with Bridgepoint Medical. Dr Grantham reports consulting/speaker honoraria from Boston Scientific, Asahi Intecc; research grants from Boston Scientific, Asahi Intecc, Abbott Vascular, and Medtronic. Dr Lembo reports speaker’s bureau fees from Medtronic; advisory board fees from Abbott Vascular and Medtronic. Dr Kandzari reports research/grant support from Medtronic, Boston Scientific, Asahi Intecc; consulting honoraria from Medtronic and Boston Scientific. Dr Thompson is an employee and stockholder of Boston Scientific. Dr Banerjee reports research grants from Gilead and The Medicines Company; consultant/speaker honoraria from Covidien and Medtronic; ownership in MDCare Global (spouse); and intellectual property in HygeiaTel. Dr Brilakis reports consulting/speaker honoraria from Abbott Vascular, Asahi Intecc, Boston Scientific, Elsevier, GE Healthcare, Somahlution, St. Jude Medical, and Terumo; research support from Boston Scientific and InfraRedx; spouse is an employee of Medtronic. The remaining authors report no disclosures regarding the content herein.
Manuscript submitted January 4, 2016, provisional acceptance given March 1, 2016, final version accepted March 14, 2016.
Address for correspondence: Emmanouil S. Brilakis, MD, PhD, Dallas VA Medical Center (111A), 4500 South Lancaster Road, Dallas, TX 75216. Email: email@example.com