Abstract: Background. Long-term outcomes of patients with prior coronary artery bypass graft (CABG) surgery undergoing chronic total occlusion (CTO) percutaneous coronary intervention (PCI) have received limited study. Methods. We compared the clinical and angiographic characteristics and procedural and follow-up outcomes of patients with and without prior CABG in a multicenter international registry. Results. Of the 1572 patients included in this analysis, a total of 498 (32%) had prior CABG. Prior CABG patients had higher J-CTO scores (2.9 ± 1.1 vs 2.2 ± 1.3; P<.001) and were less likely to undergo PCI of the left anterior descending artery (16.7% vs 29.6%; P<.001). The retrograde technique was used more often (47.4% vs 28.2%; P<.001) and was successful more often (27.4% vs 17.1%; P<.001) in the prior CABG group vs the non-prior CABG group. Technical success was lower in prior CABG patients (82.6% vs 87.9%; P<.01) with similar incidence of in-hospital major adverse cardiovascular events (3.4% vs 3%; P=.65), although in-hospital mortality was higher in the prior CABG group (2.4% vs 1.0%; P=.04). At 1-year follow-up, the composite endpoint of death, myocardial infarction, and revascularization was higher in prior CABG patients (21.79% vs 12.73%; hazard ratio, 1.76; 95% confidence interval, 1.27-2.45; P<.001). Conclusion. Compared with non-prior CABG patients, prior CABG patients undergoing CTO-PCI had lower technical success and higher incidence of acute and follow-up adverse cardiovascular events.
J INVASIVE CARDIOL 2020;32(8):315-320. Epub 2020 May 20.
Key words: chronic total occlusion, coronary artery bypass graft surgery
Although the success of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has significantly increased in recent years, patients with prior coronary artery bypass graft (CABG) surgery appear to have lower success and higher risk of complications,1,2 although there are limited long-term data.3,4 We examined the outcomes of patients with and without prior CABG in a multicenter, contemporary CTO-PCI registry.
Patient population. We analyzed the clinical, angiographic, and procedural characteristics of 1575 CTO-PCIs performed in 1572 patients enrolled in the PROGRESS CTO (Prospective Global Registry for the Study of CTO Intervention) registry between May 2012 and August 2019 who had follow-up data. Some centers only enrolled patients during part of the study period because of participation in other studies. The REDCap database was used for data collection and management.5,6 The study was approved by the institutional review board at each participating 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 duration of occlusion was clinical, based on the first onset of angina, prior history of myocardial infarction in the target vessel territory, or comparison with a prior angiogram. Calcification was assessed by angiography as mild (spots), moderate (involving ≤50% of the reference lesion diameter), and severe (involving >50% of the reference lesion diameter). Moderate proximal vessel tortuosity was defined as the presence of at least 2 bends >70° or 1 bend >90° and severe tortuosity as 2 bends >90° or 1 bend >120° in the CTO vessel. Blunt or no stump was defined as lack of tapering or lack of a funnel shape at the proximal cap. Interventional collaterals were defined as collaterals considered amenable to crossing by a guidewire and a microcatheter by the operator. Proximal cap ambiguity was defined as uncertainty about the location and shape of the proximal CTO cap. Adequate distal landing zone was defined as a distal vessel segment with a diameter >2.0 mm and without diffuse disease. A procedure was defined as retrograde if an attempt was made to cross the lesion through a collateral vessel or bypass graft supplying the target vessel distal to the lesion; if not, it was classified as antegrade-only. Antegrade wire escalation was defined as antegrade PCI during which a guidewire crossed the lesion from true to true lumen. Antegrade dissection/re-entry was defined as antegrade PCI during which a guidewire was intentionally introduced into the subintimal space proximal to the lesion, or re-entry into the distal true lumen was attempted after intentional or inadvertent subintimal guidewire crossing.
Technical success was defined as successful CTO revascularization with achievement of <30% residual diameter stenosis within the treated segment and restoration of TIMI grade 3 antegrade flow. Procedural success was defined as achievement of technical success without any in-hospital major adverse cardiovascular event (MACE). In-hospital MACE was defined as death from any case, myocardial infarction, recurrent angina requiring urgent repeat revascularization (with PCI or CABG), stroke, or tamponade requiring pericardiocentesis or surgery. MACE at follow-up was defined as the composite of death from any cause, myocardial infarction, recurrent angina requiring urgent repeat target-vessel or target-lesion revascularization (with PCI or CABG). Myocardial infarction was defined according to the third universal definition.7 Vascular access complications included small (<5 cm) hematoma, large (≥5 cm) hematoma, arteriovenous fistula, pseudoaneurysm, and acute arterial closure. The J-CTO score was calculated as described by Morino et al,8 the PROGRESS-CTO score as described by Christopoulos et al,9 and the PROGRESS-CTO Complications score as described by Danek et al.10
Statistical analysis. Categorical variables were presented as counts and percentages and were compared using Pearson Chi-square tests. Continuous variables were summarized by mean ± standard deviation or median with interquartile range (IQR) unless otherwise specified and were compared using the t-test for normally-distributed variables and the Wilcoxon rank-sum test for skewed variables. The incidence of MACE at follow-up was calculated using the Kaplan-Meier method and compared using the log-rank test.11 We used a Cox proportional hazards model to assess the relationship of baseline angiographic and procedural characteristics with the composite endpoint of death, myocardial infarction, and coronary revascularization. The following parameters (univariable association P<.10 and clinically relevant) were included in the model: ad hoc CTO-PCI, J-CTO score, technical success, prior CABG, currently on dialysis, retrograde approach, diabetes mellitus, and prior PCI. All statistical analyses were performed with JMP, version 15.0 (SAS Institute). A 2-sided P-value of .05 was considered statistically significant.
Baseline clinical and angiographic characteristics. Of the 1572 patients who underwent CTO-PCI and had long-term follow-up, a total of 498 (32%) had prior CABG. Prior CABG patients were older, presented more frequently with an acute coronary syndrome, had higher prevalence of diabetes, dyslipidemia, hypertension, and peripheral arterial disease, and were more likely to have had a prior myocardial infarction and to have undergone prior PCI. Prior valve surgery and prior heart failure were also more common in the prior CABG group. The baseline clinical characteristics are shown in Table 1.
The left anterior descending (LAD) coronary artery was less often the target vessel, while the left circumflex (LCX) was more often the target vessel in prior CABG patients as compared with the non-prior CABG group. Prior CABG patients also had longer lesions and higher rates of proximal cap ambiguity, distal cap at bifurcation, moderate/severe calcification, and moderate/severe proximal tortuosity. Lesions in patients with prior CABG were less likely to have a good distal landing zone. The mean J-CTO, PROGRESS-CTO, and PROGRESS-CTO Complications scores were higher in prior CABG patients. The baseline angiographic characteristics are included in Table 2.
Technical characteristics. Antegrade wire escalation (AWE) was used less frequently, whereas the retrograde approach was used more frequently, in prior CABG patients. The retrograde strategy was more frequently the final successful strategy in the prior CABG group, while AWE was more often the successful crossing strategy in patients without prior CABG. Epicardial collaterals were used more often for retrograde access in prior bypass patients. Finally, patients with a prior bypass were more likely to require the use of a left ventricular assist device. Technical characteristics are presented in Table 3.
Procedural, in-hospital and follow-up outcomes. Technical and procedural success rates were lower, whereas procedure time, fluoroscopy time, contrast volume, and air kerma radiation dose were higher in prior CABG patients. In-hospital mortality was higher in the prior CABG group, while the incidences of in-hospital myocardial infarction, in-hospital re-PCI, in-hospital stroke, and in hospital MACE were similar, and tamponade requiring pericardiocentesis was less common. Procedural and in-hospital outcomes are presented in Table 3.
Median follow-up was 110 days. After 1 year, prior CABG patients had higher incidence of MACE (21.8% vs 12.7%) and myocardial infarction, but similar mortality and repeat revascularization (Figure 1).
On Cox proportional hazard analysis, higher J-CTO score, diabetes mellitus, chronic kidney disease requiring dialysis, ad hoc CTO-PCI, and use of the retrograde approach were associated with follow-up MACE, whereas prior CABG was not (Figure 2).
The main findings of our study are that compared with patients without prior CABG, prior CABG patients have more comorbidities, lower procedural success, and higher incidence of subsequent MACE. Several studies have shown that prior CABG patients have multiple comorbidities. This was also the case in our study, where comorbidities such as diabetes mellitus, dyslipidemia, heart failure, and hypertension were significantly more prevalent among prior CABG patients.
As anticipated,1,3,4,12 CTO-PCI success was lower in prior CABG patients, possibly due to higher complexity, which necessitated more frequent use of retrograde crossing. Indeed, pathology studies demonstrate that CTOs in patients with prior CABG are often complex, with higher prevalence of a blunt stump, negative remodeling, and calcification.13 Use of saphenous vein grafts as collaterals can increase the technical and procedural success rates of retrograde CTO-PCI cases.14
Previous studies have also shown lower success and higher in-hospital mortality after CTO-PCI in prior CABG patients.1,12 Azzalini et al reported higher rates of target-lesion failure in prior CABG patients 1 year after CTO-PCI.3 Dautov et al reported higher risk of 1-year MACE (cardiac death, myocardial infarction, ischemia-driven target-vessel revascularization, or reocclusion).4 Our results are in line with these studies, showing a significantly higher rate of death, myocardial infarction, and revascularization in the prior CABG group. As the multivariable analysis suggests, the worse follow-up outcomes of prior CABG patients are likely related to higher risk baseline coronary anatomy (as indicated by the higher J-CTO score and higher prevalence of LCX-CTO) and more comorbidities.
Study limitations. This was an observational study, subject to selection bias. Potential confounders also exist beyond the multivariable analysis, as the operators might choose a more aggressive approach in prior CABG patients. There was no core laboratory review of angiograms or independent outcomes adjudication. All procedures were performed by experienced operators, limiting extrapolation to low-volume, non-expert operators. Finally, not all patients had follow-up data available.
CTO-PCI can be performed in prior CABG patients with high success and acceptable complication rates, although when compared with patients who have no history of prior CABG, prior CABG patients have worse in-hospital and follow-up outcomes, likely related to higher anatomic complexity and more comorbidities.
Acknowledgments. Study data were collected and managed using Research Electronic Data Capture (REDCap) electronic data capture tools hosted at the Minneapolis Heart Institute Foundation (MHIF), Minneapolis, Minnesota. 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.
From 1Minneapolis Heart Institute Foundation and Minneapolis Heart Institute at Abbott Northwestern Hospital, Minneapolis, Minnesota; 2Baylor Heart and Vascular Hospital, Dallas, Texas; 3Cleveland Clinic, Cleveland, Ohio; 4Henry Ford Hospital, Detroit, Michigan; 5Medical Center of the Rockies, Loveland, Colorado; 6St. George University Hospital Center, Beirut, Lebanon; 7Beth Israel Deaconess Medical Center, Boston, Massachusetts; 8Houston Methodist Hospital, Houston, Texas; 9Columbia University, New York, New York; and 10VA North Texas Health Care System and University of Texas Southwestern Medical Center, Dallas, Texas.
Disclosures: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Khatri reports speaker/proctor income from Asahi Intecc and Abbott Vascular. Dr Alaswad reports consulting fees from Terumo and Boston Scientific; consultant (non-financial) for Abbott Laboratories. Dr Abi Rafeh reports proctor and speaker honoraria from Boston Scientific and Abbott Vascular. Dr Lembo reports speakers’ bureau income from Medtronic; consultant/advisory board for Abbott Vascular and Medtronic. Dr Parikh reports speakers’ bureau income from Abbott Vascular, Medtronic, CSI, BSC, Trireme; advisory boards for Medtronic, Abbott Vascular, Philips. Dr Karmpaliotis reports speaker honoraria from Abbott Vascular, Boston Scientific, Medtronic, and Vascular Solutions. Dr Kirtane reports institutional research grants to Columbia University from Boston Scientific, Medtronic, Abbott Vascular, Abiomed, St. Jude Medical, Vascular Dynamics, Glaxo SmithKline, and Eli Lilly. Dr Ali reports consultant fees/honoraria from St. Jude Medical and AstraZeneca Pharmaceuticals; ownership interest/partnership/principal in Shockwave Medical and VitaBx; research grants from Medtronic and St. Jude Medical. Dr Rangan reports research grants from InfraReDx and Spectranetics. Dr Banerjee reports research grants from Gilead and the Medicines Company; consultant/speaker honoraria from Covidien and Medtronic; ownership in MDCare Global (spouse); intellectual property in HygeiaTel. Dr Garcia reports consulting fees from Medtronic. Dr Burke reports consulting and speaker honoraria from Abbott Vascular and Boston Scientific. Dr Brilakis reports consulting/speaker honoraria from Abbott Vascular, American Heart Association (associate editor, Circulation), Boston Scientific, Cardiovascular Innovations Foundation (Board of Directors), CSI, Elsevier, GE Healthcare, InfraRedx, and Medtronic; research support from Regeneron and Siemens; shareholder in MHI Ventures; Board of Trustees for the Society of Cardiovascular Angiography and Interventions.
Manuscript submitted January 28, 2020 and accepted February 5, 2020.
Address for correspondence: Emmanouil S. Brilakis, MD, PhD, Minneapolis Heart Institute, 920 East 28th Street #300, Minneapolis, MN 55407. Email: firstname.lastname@example.org
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