Cardiovascular Center Aalst, OLV Clinic, Aalst, Belgium; NationalInstitute of Health Research Cardiovascular BRU, Royal Brompton

Hospital and Imperial College, London, United Kingdom; Division ofCardiology, Federico II University, Naples, Italy; and Department of

Cardiology, Oost-Limburg Hospital, Genk, Belgium.

Am J Cardiol 2014;114:1158e1164

Introduction

• CTOs are the most challenging coronary lesions for PCI, with a success rate ranging from 55% to 100%.

• Successful PCI of CTOs is associated with improved long-term clinical outcomes compared with conservative management.

• Nevertheless, the clinical outcome even after successful recanalization remains worse compared with patients with non-CTO stenoseswho underwent PCI.

• Several risk scores based on clinical and angiographic features have assessed the probability of procedural success.

– The SYNTAX score improved decision making between PCI and CABG.

– The Euroscore often used for prediction of early mortality after open-heart surgery, has been recently proved to reliably predict short- and long-term prognosis in complex coronary interventions.

• The age, creatinine, and ejection fraction (ACEF) score has been not only validated in the setting of elective CABG but also used to risk stratify patients treated with PCI.

• We aimed in this multicenter retrospective registry at assessing the prognostic value of the ACEF score in patients who underwent successful PCI of CTO

Methods

• January 2006 to September 2012

• 715 consecutive patients who underwent PCI of CTO in major native coronary arteries were screened at 3 centers

• The ACEF score was calculated retrospectively for 587 patients eventually enrolled in the registry.

• All patients had either angina and/or viability/reversible myocardial ischemia in the territory of the occluded artery, assessed either by stress echocardiography or myocardial perfusion scintigraphy.

• A CTO was defined as a complete obstruction of a native coronary artery with duration longer than 3 months and TIMI flow vessel grade 0.

• A successful CTO procedure was defined as coronary revascularization with final TIMI flow grade 2 and full coverage with stents of the occluded segment

• Troponins, creatinine, and hemoglobin collected at baseline and at 12 to 24 hours after the procedure to detect possible periprocedural-myocardial infarction (PMI), acute kidney injury, and major bleedings.

• All patients were pretreated with aspirin and clopidogrel before the procedure.

• All patients with successful vessel revascularization received dual antiplatelettherapy with aspirin indefinitely and clopidogrelfor at least 12 months after procedure.

• The ACEF score was calculated according to the following formula: ACEF = Age/Left ventricular EF ( +1 if creatinine was >2.0 mg/dl).

• Analysis per tertile of ACEF score and clinical follow-up evaluation were performed in all patients.

• Primary end points – 2 year cumulative incidence of MACEs, defined as the composite of overall death, nonfatal myocardial infarction, and clinically driven TVR.

• Secondary end points - in-hospital incidence of PMI, major bleedings, and acute kidney injury and also overall death, nonfatal myocardial infarction, and clinically driven TVR at 2 years.

Results• PCI of CTO was successful in 433 patients (74%;

success group), whereas it failed in 154 patients (26%; failure group).

• Patients of the 2 groups were stratified according to the ACEF score tertiles as follows:

(a) success group, first ACEF <0.950 (n =147), second ACEF from 0.950 to 1.207 (n = 136), and third ACEF >1.207 (n = 150);

(b) failure group, first ACEF <0.950 (n = 47), second ACEF from 0.950 to 1.207 (n = 55), and third ACEF >1.207 (n = 52).

Discussion

• Our findings demonstrate that ACEF score can reliably predict the clinical outcome of patients successfully treated with PCI of CTO.

• In this high-risk setting, the ACEF score allowed discriminating patients remaining at higher risk of adverse outcomes despite successful PCI.

• PCI of CTOs leads to an improvement in angina, normalization of functional tests, improvement of left ventricular function, and avoidance of CABG surgery.

• Patients with successful CTO PCI have better survival compared with patients with unsuccessful procedures.

• Yet, this clinical benefit is not uniform, and in some patients even after revascularization, clinical outcome remains worse compared with patients who underwent PCI of non-CTO lesions.

• In addition, CTO remains technically challenging: (a) PCI failure is reported in up to 35% of CTOs; and (b) >40% of CTOs are not attempted and treated

either with medical therapy or with CABG.

• Patients with CTO vessels subtending large areas of myocardial ischemia or viability do certainly benefit from successful revascularizations.

• In addition, the J-CTO score has been shown as an easy and reliable tool to identify CTO lesions with high technical success rate of percutaneousrevascularization

• The ACEF score has been originally validated in surgical patients and presents the advantage of being simple and easy to calculate.

• The ACEF score has shown good predictive value in patients who underwent conventional PCI with stent implantation, even in particularly challenging lesion settings like PCI of left main coronary artery or with heavily calcified lesions who underwent rotational atherectomy.

• Our data further extend these available evidences to patients who underwent PCI of CTOs.

• First, success rate at first attempt was higher in patients of the first ACEF tertile, and these patients also experienced less frequently PMIs.

• In addition, patients of the first ACEF tertilepresented lower overall death and MACE rate.

• Here, our findings confirm a better clinical outcome compared with patients of the first ACEF tertile in whom PCI of CTO failed.

• In these latter patients, the worse clinical outcome was mainly driven by the higher rate of repeated clinically driven revascularizations, suggesting a subset of highly symptomatic patients.

• On the other side of the spectrum, patients of the third ACEF tertile with successful percutaneous revascularization of the CTO presented higher overall death, MACE rate, and lower MACE-free survival compared with patients of the lower tertiles.

• The clinical outcome of these patients was not different from that observed in patients of the third ACEF tertile in whom PCI of the CTO failed.

• These findings suggest that ACEF score was able to identify a subset of patients with CTOs who did not derive any additional clinical benefit even if successfully treated with PCI compared with patients in whom PCI failed.

• Whether CTOs in patients of the third ACEF tertileshould be managed conservatively since the beginning cannot be addressed by our study, although it represents an interesting speculation that deserves further prospective evaluation.

• For the time being, our data support a strategy that discourages additional attempts in case PCI of CTO fails in patients with high ACEF score.

• Several limitations• Inherent to retrospective studies should be acknowledged:

that is events under-reporting, inability to account for operator’s decisions, short follow up, and low event rate, especially for death and many other potential confounding factors.

• Duration of CTO was certain (i.e., angiographicallyconfirmed) in nearly 70% of the patients, whereas it was likely (i.e., clinically confirmed) in the remaining patients.

• We cannot exclude that the low MACE rate in the third ACEF tertile of the failure group (compared with the first ACEF tertile) was partly because of the reluctance of the physicians to refer these patients to surgical revascularization, given the increased surgical risk represented by advanced age, reduced left ventricular EF, and the presence of renal failure.

• Our study focused on patients already treated with PCI; therefore, a prospective validation of the prognostic value of the ACEF score in patients with CTO is warranted.

• Stent thrombosis and target lesion revascularization were not systematically assessed and, therefore, are not reported.

Conclusion

• ACEF score represents a simple tool in the prognostication of patients successfully treated with PCI of CTO and identifies those patients who would not derive any significant clinical harm despite failed percutaneousrevascularization of the CTO.