Patients undergoing attempted aorto-ostial CTO PCI at 4 high-volume centers with specialized CTO PCI programs, between February 2013 and December 2018, were included in this study. Two centers only enrolled patients during part of the study period. All procedures were indicated according to the presence of angina, evidence of ischemia, or both, and were performed electively10 by experienced operators. Clinical, angiographic, procedural, hospitalization and follow-up data were recorded. All participants gave informed consent for the procedure and for data analysis and publication.

CTO PCI was performed in all patients using the femoral or radial approach, at the operator's discretion, using simultaneous double injection, with the exception of patients with only ipsilateral collateral filling.

The patients were pretreated with dual antiplatelet therapy. In the cardiac catheterization laboratory, weight-adjusted heparin was administered to maintain an activated clotting time for> 300seconds and was monitored every 30minutes to determine whether an additional bolus of unfractionated heparin was necessary. After the procedure, all patients received 81 to 100mg of aspirin daily indefinitely and a maintenance dose of clopidogrel (75mg/d), prasugrel (10mg/d) or ticagrelor (90mg twice daily) for 6 to 12 months.

CTO was defined as an occlusive (100% stenosis) coronary lesion with antegrade Thrombolysis In Myocardial Infarction (TIMI) flow grade 0 for at least 3months.11 A CTO was considered to be aorto-ostial if the proximal cap was within 5mm of the aortocoronary ostium.8 Flush aorto-ostial occlusion was defined as the complete absence of a stump at the aortocoronary junction (figure 1). The J-CTO (Japanese-Chronic Total Occlusion) score12 and the PROGRESS-CTO score13 were calculated for each lesion.

Figure 1.

Types of aorto-ostial CTOs. A: flush aorto-ostial occlusion (total absence of a stump at the aortocoronary junction). B: aorto-ostial CTO with a minimal proximal cap. CTO: chronic total coronary occlusion.

(0.1MB).

Technical success was defined as residual stenosis <30% with TIMI 3 flow in the CTO vessel.10 Procedural success was defined as technical success plus the absence of in-hospital adverse events (all-cause death, Q-wave myocardial infarction, stroke, recurrent angina requiring target vessel revascularization with PCI or coronary artery bypass graft, tamponade requiring pericardiocentesis or surgery).10 Procedural complications and in-hospital adverse events included death, stroke, periprocedural type 4a myocardial infarction,14 need for urgent revascularization, major bleeding (bleeding requiring transfusion, vasopressors, surgery, or percutaneous intervention), vascular complications, coronary perforation requiring intervention (coil embolization, covered stent implantation, pericardiocentesis, and/or surgery), and contrast-induced nephropathy (increase in serum creatinine> 25% or> 0.5 mg/dL at 48hours postprocedure). Major adverse cardiac events (MACE) on follow-up were defined as a composite of cardiac death, myocardial infarction, and clinically-driven target lesion revascularization.

Clinical follow-up was performed with scheduled visits and telephone calls. Patients with symptom recurrence or with inducible ischemia were recommended to undergo angiographic evaluation.

Continuous variables are expressed as the mean±standard deviation or median [IQ25-75]. Categorical variables are presented as counts and percentages. Independent predictors of recanalization failure were studied using a backward stepwise logistic regression model. Variables with a P-value of ≤ .1 in univariate analyses and those previously linked with technical failure were introduced into the model. The final model included the following variables: flush ostial CTO, blunt stump/proximal cap ambiguity, moderate-severe calcification, moderate-severe tortuosity, occlusion length> 20mm, in-stent CTO and the absence of interventional collaterals. A P value of <.05 was considered statistically significant. Model fit was evaluated with the Hosmer-Lemeshow goodness-of-fit test. Statistical analyses were performed using SPSS, version 20 (IBM Corp., United States).

During the study period, 1371 patients underwent CTO PCI at the 4 participating centers. Of these, 103 (7.5%) patients had an aorto-ostial CTO and were included in this registry. Clinical characteristics of the study population are shown in table 1. Mean age was 64±10 years and 90.3% of the patients were men. The prevalence of cardiovascular risk factors was high: half of the study population had prior myocardial infarction, three quarters prior PCI, and one quarter prior coronary artery bypass grafting. The most frequent indication for CTO PCI was angina despite optimal medical treatment.

The angiographic features of the target lesions are presented in table 2. The most frequent target CTO vessel was the right coronary artery (n=96, 93.2%). Six patients (5.8%) underwent PCI of an occluded left main coronary (figure 2) and 1 patient (1%) had a CTO of a circumflex artery with a separate ostium. The mean J-CTO score was 3.1±1.1. Most CTOs had moderate or severe calcification (n=63; 61.2%) and proximal cap ambiguity (n=76; 73.8%). Additionally, flush ostial CTOs were present in 34 (33.0%) of the patients.

Figure 2.

Left main CTO after Jatene surgery. Ostial left main CTO after Jatene surgery. Contralateral filling from the RCA and LCx (anomalous origin of the LCx from the RCA) (arrows) (A, B). A retrograde approach was chosen (C). A Sion guidewire (Asahi Intecc, Japan) was advanced through a microcatheter from the RCA to the diagonal branch, reaching the distal cap of the occlusion (arrow) (D). A Pilot 200 (Abbott, United States) passed into the aorta (arrows) (ER). The externalization guidewire was snared to create the circuit (F). Final result after drug-eluting stent implantation (G). CTO, chronic total coronary occlusion; LCx, left circumflex coronary artery; RCA, right coronary artery.

(0.2MB).

The procedural data of this cohort are shown in table 3. The access site was bifemoral or radial-femoral in most of the patients (n=89; 86.4%). A single guide catheter was used in 12 (11.6%) patients. The retrograde approach was the initial crossing strategy in most patients (n=62; 60.2%), as well as the final successful strategy: retrograde wire escalation in 17 (21.5%) patients and reverse controlled antegrade and retrograde tracking in 32 (40.5%). In flush ostial CTOs, retrograde strategies were the successful crossing techniques in an even higher proportion of cases (n=19/23, 82.6% vs n=30/56, 53.6%, in flush vs no flush ostial CTO; P=.02). However, in patients with in-stent CTO, antegrade techniques were the most common successful recanalization strategies (n=12/18, 66.7% vs n=18/61, 29.5%; P=.01).

Guidewire externalization after retrograde crossing was commonly performed using the conventional technique using a long externalization wire (n=30/49, 61.2%).

Technical and procedural success were achieved in 79 (76.7%) and 78 (75.7%) of the patients, respectively. In our series, the success rate of nonaorto-ostial CTOs was significantly higher (89.8% vs 76.7%, P <.001). Moreover, there was a trend toward a lower technical success rate in the flush ostial CTOs in comparison with no flush CTOs (23/34, 67.6% vs 56/69, 81.2%; P=.13). The reasons for failed recanalization were the following: absence of interventional collaterals in 14/24 patients (58.3%), presence of an impenetrable proximal cap in 7 (29.2%), and inability to advance the microcatheter through the collaterals after successful wiring in the remaining 3 patients (12.5%).

In-hospital complications are presented in table 4. Periprocedural MI was diagnosed in 6 (5.8%) patients, and was associated with a coronary perforation requiring intervention in 2 of them. In the remaining patients, this was an asymptomatic event with no clinical consequences. We observed 4 coronary perforations (3.9%), which were all successfully treated with covered stent implantation, without subsequent cardiac tamponade. Vascular complications were observed in 6 (5.8%) patients, mainly minor complications consisting of local hematoma (n=4, 3.9%). Two patients had a major bleeding at the puncture site (1.9%). Other complications included contrast-induced nephropathy (n=4; 3.9%) without the need for dialysis, transient ischemic attack (n=1; 0.9%) and stroke (n=1; 0.9%).

During a median follow-up of 31 months [16.5-44], the MACE rate was 15.5%. Five (4.8%) patients died, 3 of them (2.9%) from cardiovascular causes and 2 (1.9%) due to noncardiac causes (end stage chronic kidney disease and pulmonary disease). Thirteen patients (12.6%) required repeat target vessel revascularization due to focal restenosis in 4 patients (30.8%), diffuse in 6 (46.1%) and reocclusion in the remaining 3 patients (23.1%). Twelve patients had been previously treated with second generation drug-eluting stents and 1 patient with a bioresorbable scaffold.

With regard to the patients with successfully treated in-stent CTO, only 1 of them needed repeat target vessel revascularization because of a new reocclusion.

Factors associated with technical failure are presented in table 5. The absence of interventional collaterals was the only factor associated with a higher risk of technical failure (OR, 12.38; 95% confidence interval, 4.02-38.15; P <.001).

This was a retrospective registry without core laboratory assessment of the study angiograms and adjudication of clinical events by a clinical events committee. Moreover, the procedures were performed in high-volume CTO centers by experienced operators: as a consequence, our study findings might therefore not be generalizable to other less experienced operators. Finally, the sample size was relatively small and comparison with a group of nonaorto-ostial CTOs was not possible.