Discussion:
Surgical revascularization has been proven favorable strategy for patients with diabetes, left main disease, and multivessel coronary artery disease. However, around 20% of these patients may not qualify for surgery due to various reasons, such as subjective decision-making by operators, inadequately accounted factors in surgical risk models (poor targets), exclusion of certain patients from clinical trials, historical preference for PCI as the primary treatment, and limited recommendations from societal guidelines [4]. The main goal of surgical approach is to ensure complete revascularization, particularly in patients who received 3 or more grafts, as this has been associated with improved survival compared to those who received <3 grafts [6]. This goal has been extrapolated to percutaneous revascularization, but its applicability to stable coronary disease remains controversial due to disparity of data. However, in patients with acute coronary syndromes with elevation of the ST segment, complete percutaneous revascularization has been shown to improve outcomes [7]. During PCI, the completeness of revascularization is crucial, as higher residual SYNTAX score has been associated with worse 5-year mortality [8].
Coronary CTO PCI is complex and requires additional training and deep understanding of different techniques. It has higher potential periprocedural complications, and limited evidence of survival benefits. However, CTO PCI is part an essential part of the corpus of complex high-risk intervention in indicated patients (CHIP), in fact it has been increasingly considered as an alternative to coronary artery bypass graft surgery. Mechanical circulatory support (MCS), specifically the Impella device, has been utilized to facilitate PCI in these patients following successful outcomes in PROTECT studies [9,10], leading to its widespread usage in catheterization laboratories.
Hemodynamically supported revascularization is commonly performed in patients with a LVEF ≤35%, but it is not exclusive to this group. Despite advancements in procedural techniques, equipment, and the implementation of a systematic hybrid approach, CTO PCI still faces challenges due to the high-risk characteristics of many patients, particularly those with impaired left-ventricular function [11,12]. Different CTO PCI technical success rate has been reported in the literature so far. A 2021 PROGRESS-CTO Registry demonstrates a high technical success rate (85%) and a low incidence of in-hospital major adverse cardiac events (MACE) (2.1%) [13]. Data has also shown that the retrograde technique, as in our case, can increase the technical success rate, but it is associated with increased rates of complications [14,15].
The effectiveness of CTO PCI in relieving angina has been well established. Following the procedure, our patient reported significant symptomatic relief on a 3-month follow-up visit. Several studies have demonstrated improved angina symptoms following successful CTO PCI [16,17]. In comparison to patients with unsuccessful CTO PCI, the OPEN-CTO registry reported statistically significant improvement in the Seattle Angina Questionnaire Quality of Life Score and Rose Dyspnea Scale score compared with the unsuccessful procedure [18]. Similarly, the European CTO club reported improvement in dyspnea and angina after a follow-up period of 23 months [19].
Although data has significant limitations, CTO PCI does not appear to affect all-cause mortality (one-year relative risk [RR] 1.70, 95% CI 0.50-5.80 and four-year RR 1.77, 95% CI 0.19-16.06), myocardial infarction (one-year RR 1.01, 95% CI 0.43-2.36 and four-year RR 1.46, 95% CI 0.75-2.87), or cardiovascular disease mortality (one-year RR 1.14, 95% CI 0.38-3.40 and four-year RR 2.05, 95% CI 0.8-5.28) when compared to optimal medical management [20]. This finding aligns with the limited benefits of PCI revascularization in stable coronary artery disease [21], understanding that this population of not surgical candidacy has a high comorbidity burden that impacts mortality. Another consideration is that revascularization with hemodynamic support may be associated with a higher occurrence of in-hospital major adverse cardiac and cerebrovascular events (MACCE), which is likely attributed to the selective use of mechanical support in patients with higher risk profiles [22].
The data regarding LV systolic function is also not uniform. Recent REVIVED-BCIS2 trial failed to show all-cause mortality (HR 0.99, 95% CI 0.78-1.27) or LV systolic function benefits at 6 months (mean difference, −1.6 percentage points; 95% CI, −3.7 to 0.5) and at 12 months (mean difference, 0.9 percentage points; 95% CI, −1.7 to 3.4) compared with optimal guideline-directed medical therapy, regardless of viability characteristics at baseline [23], although about 30% of modalities used to assess viability were other than CMR. Contrary, RESTORE-EF observational study reported significant improvement in LVEF at 90 days from 35 ± 15% to 45 ± 14% (p < .0001 ) [24]. Moreover, this study revealed a substantial relative reduction of 76% in NYHA class III/IV heart failure symptoms and an impressive relative reduction of 97% in CCS angina class III/IV symptoms from the baseline measurements to the post-PCI period. The improvement in LVEF was observed exclusively in patients with LVEF below 45%, whereas the improvement in heart failure and anginal symptoms was noted across the entire spectrum of LVEF. The disparity between these two trials is likely due to differences in the study population. In the later trial, patients had higher rates of left main disease and more extensive coronary disease. Angina was also more frequent and severe in the later trial. Additionally, in the REVIVED-BCIS2 trial, two-thirds of the patients had not been hospitalized in the previous two years, and there were no cases of NSTEMI.
In conclusion, our case highlights the potential benefits of complex high-risk PCI with mechanical support and the potential benefits of CTO PCI to improve LV function.
Author contribution:
Stefan Milutinovic - Conceptualization, resources, Writing – original draft
Kamaldeep Singh - Resources, Writing – Review and Editing, Supervision
Stevan Oluic - Conceptualization, resources, Writing – original draft
Juan C. Lopez-Mattei - Visualization, Supervision, Writing – Review and Editing
Ricardo O. Escárcega - Resources, Writing – Review and Editing, Supervision