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