Author + information
- Kambis Mashayekhi, MD∗ (, )
- Hans Neuser, MD,
- Anna Kraus, MD,
- Matthias Zimmer, MD,
- Jörg Dalibor, MD,
- Ibrahim Akin, MD,
- Gerald Werner, MD,
- Toma Aurel, MD,
- Franz-Josef Neumann, MD and
- Michael Behnes, MD
- ↵∗Division of Cardiology and Angiology II, University Heart Center Freiburg – Bad Krozingen, Südring 15, 79189 Bad Krozingen, Germany
Percutaneous coronary intervention (PCI) of chronic total occlusions (CTO) is recommended in patients with an expected reduction of angina pectoris or of ischemia in the corresponding myocardial territory (1). However, the prognostic benefit of successful PCIs in CTOs—especially in patients with a coronary 1-vessel disease—compared to optimal medical therapy is still under debate (2,3). Therefore, the indication for CTO-PCIs in patients with stable angina almost relies on symptoms’ relief. Noteworthy, angina pectoris is not the exclusive symptom in patients with coronary artery disease including those with a CTO, whereas limitations of daily exercise or increasing dyspnea may occur. Cardiopulmonary exercise testing (CPET) being assessed by spiroergometry reflects the functional capacity of individual patients with heart failure by proving decreases or improvements of peak oxygen consumption.
The present study was performed as a prospective multicenter study. Patients with a coronary CTO as the only remaining target lesion being assessed by coronary angiography were included. All patients underwent transthoracic echocardiography both before index PCI and at midterm follow-up to screen for wall contractility and viability. Those patients revealing severe hypokinesia or akinesia being assessed by echocardiography were further assessed by additional myocardial ischemia testing or cardiac magnetic resonance imaging with viability testing. Baseline CPET was performed by spiroergometry 1 week before index CTO-PCI. Midterm follow-up consisted of coronary reangiography and recurrent spiroergometry 7 months after index PCI. Patients participating in an exercise rehabilitation program after CTO-PCI were excluded. Statistical analyses comprised paired Student t tests to evaluate overall longitudinal changes of exercise capacity over time within the total cohort. For subgroup analyses, interaction testing was performed by analysis of variance for repeated measurements (PROC MIXED) by SAS Version 9.4 (SAS Institute Inc., Cary, North Carolina) with patient ID as random factor, time and subgroup as fixed factors. A 2-tailed p value of < 0.05 indicates statistical significance.
From October 2013 to October 2015, a total number of 73 patients were screened for this study. Complete and adequate follow-up (including index spiroergometry, index PCI, follow-up coronary reangiography, and spiroergometry) was available in a total of 50 patients with a median follow-up of 218 (interquartile range: 189 to 293) days, which were finally analyzed. In these 50 patients, a complete revascularization rate of 100% was achieved. A total of 76% revealed an excellent angiographic result at midterm follow-up. De-novo stenoses occurred in 10% and in-stent restenoses requiring re-PCI occurred in 14%. All restenoses were focal and treated by drug eluting balloon angioplasty. Mean SYNTAX (Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) score at baseline was 15.01 and residual with 2.15 at midterm follow-up.
In all 50 patients, CPET at baseline compared to follow-up revealed a significant increase of peak oxygen consumption (Vo2max) (16.59 ± 5.10 ml/min/kg vs. 18.42 ± 5.25 ml/min/kg) corresponding to an increase of +12.40% (p = 0.001). Accordingly, significant increases of work rate (+13.62%), anaerobic threshold (AT) (+27.87%), and oxygen pulse (+8.75%) were assessed at follow-up (p < 0.003). Breathing reserve improved only numerically (6.12%; p = 0.204). Mean left ventricular ejection fraction improved from 52.08% to 54.48% (p = 0.007). Moreover, a significant improvement of patients’ symptoms was achieved, according to an improvement of New York Heart Association functional class and Canadian Cardiovascular Society classification (p = 0.0001) (Table 1).
The improvement of exercise capacity in between baseline and midterm follow-up was also evident in several subgroups: Peak oxygen consumption improved independently of the CTO artery (left anterior descending artery [14%], circumflex artery [20%], right coronary artery [66%]) and baseline left ventricular ejection fraction (≤50% [26%] vs. >50% [74%]). Accordingly, changes of Vo2max were comparable in patients with antegrade (64%) or retrograde (36%) approach, with J-CTO (Multicenter CTO Registry in Japan) score ≥2 (40%) or 0 to 1 (60%), and in patients with (14%) or without (46%) re-PCI (p > 0.05 [for interaction]). Patients with a periprocedural myocardial infarction (MI) (18%) revealed a significantly lower change of Vo2max over time (MI: mean change 37.00 ml/min [95% confidence interval: –51.65 to 125.65 ml/min]; no MI: mean change 200.76 ml/min [95% confidence interval: 141.21 to 260.30 ml/min; p = 0.0162 [for interaction]) (data not shown).
This study demonstrates for the first time that PCI of CTOs improves cardiopulmonary exercise capacity being assessed objectively by CPET/spiroergometry at midterm follow-up. As currently recommended, proof of large ischemic burden or worsening of symptoms represent the main reasons for indicating coronary angiography for check-up after successful CTO-PCI. Noteworthy, it was shown that cardiopulmonary exercise capacity at midterm follow-up is limited in patients with index periprocedural MI, whereas it improved independently of an antegrade/retrograde approach or of the severity of the CTO lesion.
Whether CPET might serve as a noninvasive examination to detect patients with the need for re-PCI due to limited exercise capacity justifying invasive coronary reangiography at follow-up needs to be evaluated in further studies including a larger sample size and parallel medical therapy arm, and therefore generalizability of the present results is in part limited.
Please note: The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- American College of Cardiology Foundation
- ↵Windecker S, Kolh P, Alfonso F, et al. ESC/EACTS guidelines on myocardial revascularization. Eur Heart J 2014;35:2541–619.
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