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Page 4 of 7 Dobric et al. Vessel Plus 2019;3:26 I http://dx.doi.org/10.20517/2574-1209.2018.77
[24]
ventricular volumes and ejection fraction (secondary endpoint) in the CTO territory . The change in
SWT did not differ between the CTO PCI [4.1 (-14.6 to 19.3)] and non CTO PCI [6.0 (-8.6 to 6.0)] groups
[24]
(P = 0.57). Similar findings were described for secondary endpoints .
EuroCTO (Randomized Multicentre Trial to Compare Revascularization With Optimal Medical Therapy
for the Treatment of CTO) trial was the first randomized clinical trial that demonstrated some measurable
[25]
clinical benefit of PCI for CTO . This prospective randomized controlled clinical trial enrolled 396
patients to compare PCI of CTO with optimal medical therapy, with a 2:1 randomization ratio. This trial
showed that at 12 months, there was a greater improvement of Seattle angina questionnaire subscales with
PCI vs. OMT for angina frequency (5.23, 95%CI: 1.75-8.71; P = 0.003), and QOL (6.62, 95%CI: 1.78-11.46;
P = 0.007). Physical limitation (P = 0.02) also showed improvement in the PCI group. Complete freedom
from angina was encountered more frequently with PCI (71.6%) than with optimal medical therapy
(57.8%) (P = 0.008). Nevertheless, this study did not show improvement in hard clinical end point event
rates in PCI group (although not statistically significant, number of deaths and myocardial infarctions were
numerically higher in PCI group). This led investigators to conclude that PCI for CTO leads to a significant
improvement of the “health status” in patients with CTO as compared with optimal medical therapy
alone .
[25]

On the contrary, recently presented DECISION-CTO trial [26] showed no difference between PCI and
optimal medical treatment in SAQ subscales. This discrepancy with EuroCTO trial results could be
explained by study design: in EuroCTO trial there was no influence of non-CTO lesions on endpoints
(these lesions were treated before randomization), while in DECISION-CTO trial non-CTO lesions were
treated after randomization, which could potentially have some influence on study endpoints .
[25]

Overall, the amount of high-quality data from randomized clinical trials on positive effects of CTO
recanalization is relatively small. Effects are probably limited to improvement in QOL, while it was not
possible to demonstrate positive effects on hard clinical outcomes such as mortality and myocardial
infarction. However, in modern era of treatment of coronary artery disease, it is becoming more and
more difficult to make further improvements in outcomes in the treatment of coronary artery disease,
because contemporary medical treatment and overall treatment strategies have already yielded excellent
results. It was not possible to demonstrate the clinical benefit of standard PCI (and revascularization in
general) over optimal medical therapy alone, in stable coronary artery disease patients [27,28] . This means
that task for proving the clinical benefit of PCI for CTO is even more difficult, having in mind inherent
lower procedural success rate, higher rate of complications, and lower amount of viable myocardium in the
territory of vessel irrigation which usually have developed collateral circulation.

Clinical indications for PCI for CTO
Most important factors that must be taken into consideration before proceeding to CTO-PCI are the
presence of symptoms and objective evidence of ischemia, while in cases of left ventricular regional wall
motion abnormalities in the CTO territory, objective evidence of viability should be sought. The decision
to attempt PCI for CTO should be weighted against the risk of larger amount of administered contrast,
[11]
longer time of fluoroscopy, and higher rates of MACE compared with PCI for non-CTO lesion . These
factors taken together could be shown in the algorithm proposed by the EuroCTO club (Figure 1, modified
[12]
from ). We must emphasize the importance of optimal medical therapy for the control of stable coronary
artery disease, which must be the first line of intervention in patients having CTO. In recent 2018 ESC/
EACTS Guidelines on myocardial revascularization, it is recommended that percutaneous revascularization
of CTOs should be considered in patients with angina that is resistant to medical therapy alone or with a
documented large area of ischemia in the territory of CTO (class of recommendation IIa, level of evidence
B) . The class of recommendation/level of evidence for PCI of CTO was not changed from the previous
[29]
[30]
version of the Guidelines .