Author + information
- Anton A. Obedinskiy,
- Evgeny I. Kretov,
- Marouane Boukhris,
- Vladislav P. Kurbatov,
- Alexander G. Osiev,
- Zied Ibn Elhadj,
- Nataliya R. Obedinskaya,
- Sami Kasbaoui,
- Igor O. Grazhdankin,
- Alexey A. Prokhorikhin,
- Dmitry D. Zubarev,
- Alexey Biryukov,
- Evgeny Pokushalov,
- Alfredo R. Galassi and
- Vitaly I. Baystrukov∗ ()
- ↵∗E.N. Meshalkin National Medical Research Center, Rechkunovskaya Strasse 15, Novosibirsk, 630055, Russia
Despite concordant outcome data from a thousand registries comparing successful versus unsuccessful CTO PCI (1), recent randomized trials did not support the impact on survival of CTO PCI compared with OMT (2). In contrast, more certainty exists about its importance in improving QoL (2).
The IMPACTOR-CTO (Impact on Inducible Myocardial Ischemia of PercutAneous Coronary InTervention versus Optimal Medical TheRapy in Patients with Right Coronary Artery Chronic Total Occlusion) trial is a single-center randomized trial powered to investigate the impact on inducible ischemia burden of PCI versus OMT (≥2 antianginal agents) on functional status and QoL in patients with isolated RCA CTO.
From October 2010 to April 2014, patients with isolated dominant RCA CTO and stable angina were screened. After baseline adenosine stress cardiac magnetic resonance, patients were randomly assigned (1:1) to either CTO PCI associated with OMT or OMT alone. Patients who underwent unsuccessful CTO PCI attempts and those noncompliant with OMT were excluded from the study. Adenosine stress cardiac magnetic resonance was performed at baseline (before randomization) and at 2 and 12 months. MIB was estimated as a percentage as previously described (3). Functional status was evaluated using the 6-minute walk test, and QoL was measured using the Short Form-36 Health Survey.
The primary endpoint was the ΔMIB, defined as the decrease in MIB from baseline to 12-month control. The secondary endpoints were changes in 6-min walk distance, QoL, and MACE occurrence (defined as the composite endpoint of all-cause death, myocardial infarction, and unplanned revascularization) at 12 months.
Among 317 patients with CTO screened, a total of 94 eligible patients with isolated RCA CTO (29.6%) were randomly allocated to either the PCI or the OMT. In the PCI group, failed CTO PCI was observed in 8 patients, for an overall angiographic success rate of 83%. In the OMT group, 14 patients were excluded for noncompliance with OMT. Thus, 39 and 33 patients were included in the PCI and OMT arms, respectively. The mean age of the study population was 56.6 ± 8.1 years, and 83.3% were men. No difference was observed in baseline clinical and angiographic characteristics between the PCI and OMT groups.
In the PCI group, MIB significantly decreased from 27.7 ± 8.5% at baseline to 16.1 ± 8.6% at 12 months (p < 0.01), whereas no significant changes were observed in the OMT group (from 28.4 ± 8.6% at baseline to 27.0 ± 8.0%; p = 0.83). Hence, ΔMIB was significantly higher in the PCI group in comparison with the OMT group (13.9 ± 6.1% vs. 0.3 ± 4.2%; p < 0.01) (Figure 1A).
Six-minute walk distance significantly increased in the PCI group from 295 m (interquartile range [IQR]: 261 to 363 m) at baseline to 430 m (IQR: 360 to 452 m) at 12 months (p < 0.01). Conversely, no improvement was observed in the OMT group (356 m [IQR: 286 to 425 m] and 378 m [IQR: 290 to 420 m] at baseline and 12 months, respectively, p = 0.71). At 12 months, patients who underwent successful CTO PCI showed an improvement in each item of the Short Form-36 Health Survey compared with baseline. Conversely, no QoL parameters improved in the OMT group (Figure 1B).
Among patients who underwent CTO PCI attempts, 4 of 47 (8.5%) experienced periprocedural complications: 2 vascular complications and 2 tamponades. No death was observed in either group. In the PCI group, 2 patients underwent target vessel revascularization 5 and 6 months following the index procedure. No significant difference was found in MACE-free survival between the PCI and OMT groups at 12 months (94.9% vs. 100%; p = 0.19).
There is a growing need to understand whether a reduction in pre-PCI ischemic burden, particularly in the setting of CTO, relates to a subsequent improvement in QoL and clinical outcome. The DECISION-CTO and the EuroCTO trials are yet unpublished randomized studies comparing CTO recanalization and OMT (2). The majority of patients included in both studies had multivessel disease (72% and 51.5%, respectively) (2). In both studies, the composite clinical outcome was similar between the PCI and OMT groups at 5- and 1-year follow-up. Whereas DECISION CTO showed no difference in QoL between the 2 groups, the EuroCTO trial suggests favorability of CTO PCI (2). This difference between the 2 randomized studies might be because randomization was done before non-CTO PCI in DECISION-CTO. Hence, the improvements in QoL parameters observed in the OMT arm of this latter trial could be related not to OMT prescribed for untreated CTO but to PCI of non-CTO lesions. The IMPACTOR-CTO trial confirmed the results of the EuroCTO trial by showing the importance of CTO PCI in improving functional status and QoL in the setting of single-vessel disease, with no impact on clinical outcome.
Our study had some limitations. In addition to its single-center design, the comparisons between the PCI and OMT groups were made per protocol and not intention-to-treat. Further randomized trials with larger samples should be performed to better determine the most appropriate strategy to adopt in the presence of isolated RCA CTO.
Please note: The authors have reported that they has no relationships relevant to the contents of this paper to disclose.
- 2018 American College of Cardiology Foundation
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