European Journal of Cardiovascular Medicine

Chronic total occlusions (CTOs) are found in 18.4% to 52% of patients with coronary artery disease (CAD) who undergo coronary angiography.^1,2In recent years, significant advancements have been made in CTO PCI techniques, including the development and widespread adoption of the retrograde approach, antegrade dissection/re-entry techniques, and the systematic "hybrid" approach.³ As a result, some centres in Europe, Japan,⁵ the United States,⁴ and Canada now consistently achieve technical success rates exceeding 80%. Despite these advancements, there is still debate about the relative benefits and risks of CTO PCI. This procedure is classified as a Class IIa indication in the American Heart Association/American College of Cardiology⁶ PCI guidelines. Additionally, patients with CTOs receive lower ratings in 5 out of 18 categories in the PCI appropriateness use criteria.⁷ This study aimed to evaluate the short-term clinical outcomes of CTO PCI at a tertiary care hospital in South India

Patient selection:

Inclusion criteria waspatients age above 18 years who consent to participate in the study. Exclusion criteria arepatients not giving an informed consent, preexisting severe renal, Hepatic, pulmonary or other severe systemic diseases and those presenting with acute coronary syndrome.

Statistical analysis:

 Statistical analysis of the data was performed using SPSS20.0(IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp). Descriptive statistics was expressed using frequency, percentage, mean and standard deviation. A p value <0.05 will be considered statistically significant.

Patient characteristics:

Out of a total sample of 212 individuals, Mean age was 58.41 years, most patients (84%) were men.Out of the total, 79 patients (37.3%) had chronic coronary syndrome, 12 (5.7%) had history of unstable angina, 69 (32.5%) had history of NSTEMI, and 52 (24.5%) presented with history of STEMI. The distribution of comorbidities shows that 128 patients (60.4%) have diabetes mellitus, 131 (61.8%) have hypertension, and 124 (58.5%) have dyslipidaemia.

Incidence of angiographic success and procedural complications:

In the sample of 212 individuals, 53 (25%) experienced technical failure, while 159 (75%) achieved technical success. This indicates a high rate of successful outcomes in the procedures performed.The reported incidence shows that 26 patients (12.3%) experienced coronary dissection, while 13 (6.1%) had coronary perforation. Additionally, 9 patients (4.2%) developed cardiac tamponade requiring urgent intervention.Death, stroke, and urgent revascularization were common complications with rates of 0.9%, 1.9%, and 3.3%, respectively, (Table 1)

Table 1: Frequency of Complications in CTO PCI

Successful versus unsuccessful procedures

Unsuccessful procedures had significantly higher rates of coronary dissection (34% vs. 5%, p < 0.0001), perforation (17% vs. 2.5%, p < 0.0001), and tamponade (9.4% vs. 2.5%, p = 0.031) compared to successful procedures. However, there were no significant differences between unsuccessful and successful PCI in terms of death (0% vs. 1.3%, p = 0.412), peri-procedural MI (0% vs. 1.9%, p = 0.314), urgent revascularization (1.9% vs. 3.8%, p = 0.506), or stroke (3.8% vs. 1.8%, p = 0.244). Table 2

Table 2 Association between complication and technical success

The aim of our study is to assess the angiographic success and procedural complication rates of CTO PCI.

Technical success:

Overall success rate of CTO PCI is 75%, this is slightly lower than published series from Japan and Western literature.^8,Recent data from a multicentre registry shows that the success rate of the antegrade-only technique is 64% for patients with a J-CTO score of 1 and 47% for those with a score of 2.¹⁰ However, with the use of the retrograde approach and the hybrid algorithm, success rates have been reported to rise to 86%-90%, even in more complex cases or those that were previously unsuccessful with the antegrade-only technique. We attribute the lower success rate in our study to the limited use of highly complex techniques, such as IVUS-guided true lumen puncture after sub-intimal entry (only 1% in this series), and the lower use of the retrograde approach (1.4%) compared to Japanese and Western cohorts, where it is employed in up to 30% of cases.

Complications

Although technical success to treat CTO with PCI remains the goal of every interventional cardiologist, success should not be achieved at the cost of patient safety.Failure without complications is better than the success with severe complications.It is essential for the operator to fully understand the limitations and risks associated with each technique and instrument, and to use them with careful judgment. Given this ethical perspective, we chose to avoid aggressively attempting to treat lesions that could not be easily crossed.

Death, stroke and urgent revascularization

The most serious potential complications of any PCI procedure include death, urgent revascularization, and stroke. In one of the largest previously published series of 2,007 patients undergoing CTO PCI, the reported rates of death, urgent revascularization, and stroke were 1.3%, 0.7%, and 0.01%, respectively. Compared to our study, which observed incidences of 0.9%, 3.3%, and 1.9% for death, urgent revascularization, and stroke, respectively, the data demonstrates higher rates of these major complications in our study population.

Coronary dissection, perforation and tamponade

Coronary dissection and perforation are among the most feared complications of CTO PCI, due to the risk of tamponade.Most coronary dissections and perforations do not lead to tamponade and can typically be managed conservatively.¹² Similarly, in our study, coronary artery dissection occurred in 12.3% of patients and coronary artery perforation in 6.1%. However, only 4.2% of patients developed tamponade, indicating that most of the perforations were self-limited. In fact, in our study, non-serious coronary dissection was the most significant reason for deferring the continuation of CTO PCI, leading to unsuccessful results.

Successful versus unsuccessful procedures and complications

CTO PCI carries an increased risk of perforation due to the routine use of stiff and polymer-jacketed guidewires, along with frequent uncertainty about the vessel's course. Our study demonstrates that unsuccessful procedures had significantly higher rates of coronary perforation and tamponade compared to successful procedures, as they often involve more manipulation of CTO devices. Although minor complications such as self-limiting dissection, perforation, and tamponade occur more frequently in unsuccessful CTO PCI, our study found no significant difference in rates of death, stroke, or urgent revascularization. Hence, it is crucial for every CTO PCI program to have the necessary equipment for managing perforations, such as covered stents and coils.¹³

CTO PCI carries a slightly higher risk of complications compared to routine elective PCI. Failed CTO interventions are associated with a higher incidence of complications such as coronary dissection, coronary perforation, and cardiac tamponade compared to successful CTO interventions. Although periprocedural MI, death, and urgent revascularization occurred more frequently in successful attempts, these differences are not statistically significant.

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