European Journal of Cardiovascular Medicine

Chronic total occlusions (CTOs) are considered to be 100% occlusion of coronary arteries, of more than 3-month evolution. Though they are commonly found in patients with chronic stable angina, they are also seen associated with patients having Non ST-segment elevation MI (NSTEMI)and in Unstable Angina (UA) patients, with varying levels of symptoms. After the culprit artery has been treated, in patients with acute coronary syndrome(ACS) the CTOs in other artery that was not responsible for the acute event, should also be addressed. CTO interventions were historically associated with a high rate of procedural complications. But with the improvement in technology and operator skills, the complication rate has come down. Several studies have demonstrated that successful CTO revascularization has translated into better cardiovascular outcomes and improved quality of life. 

Definition of Chronic Total Occlusion (CTO)

Chronic Total Occlusion (CTO) is defined as a complete blockage of a coronary artery that has persisted for more than three months. This condition typically results from atherosclerosis, leading to the total occlusion of the arterial lumen, which impairs blood flow to the myocardium. CTOs can significantly affect cardiac function and are associated with various clinical manifestations, including angina and heart failure.^1,2,3

CTO angioplasty is a specialized interventional procedure designed to treat complete blockages in coronary arteries that have persisted for an extended period, typically defined as more than three months. CTOs present unique challenges in the field of cardiology, as they often lead to reduced myocardial perfusion, angina, and a higher risk of adverse cardiovascular events.

The procedure involves the use of advanced techniques and tools, including guidewires, balloons, and stents, to navigate through the lesions and restore cieculation to the affected heart muscle. Successful CTO angioplasty can significantly improve a patient’s quality of life, alleviate symptoms, and reduce the risk of further cardiac complications.

As the understanding of CTO management evolves, advancements in technology and techniques continue to enhance the safety and efficacy of this procedure. This introduction outlines the importance of CTO angioplasty in the broader context of cardiovascular health, highlighting its role in improving patient outcomes and guiding future research and clinical practices.

Prevalence and occlusion characteristics

The incidence of CTO varies between 10 and 30% of all coronary angiograms depending upon type of population studied. The incidence of CTOs was rather high in the thrombolysis era, with registries from the 1990s reporting incidences of ~50% in patients undergoing diagnostic coronary angiography. This incidence has decreased over the past two decades, and a CTO is now reported to be present in approximately 20% of patients undergoing coronary angiography and in approximately 15% of patients with acute ST-segment elevation myocardial infarction (STEMI) ^[4–7]  .If STEMI patients’ coronary angiography CAG shows CTO in a non-infarct related artery then CTO is independent predictor for both early mortality and late mortality. During any situation if there is hampering of blood flow to collaterals to the occluded vessel or acute impairment of preexisting collaterals from the acutely occluded vessel to the CTO jeopardizing a large myocardial territory, which also explains the prognostic benefit of reanalyzing CTOs.

Lesion characteristics play an important role in the likelihood of a successful recanalization. Morino et al introduced a lesion-related difficulty grading tool, the J-CTO score, based on a large series of anterograde recanalization in Japan ⁸ 1) CTO length greater or lesser than 20 mm; 2) Presence of a greater than 45 degrees bend within the occlusion; 3) Presence of intralesional calcification; 4) Entry shape tapered or blunt; 5) Previous failed attempt.

Lesions with J-CTO score of 0 - 1 had high success rate > 90% and difficult lesion labeled for J-CTO score ≥ 3, had 73.3 % success rate and need prolonged time for crossing. Technical progress and the introduction of the retrograde approach have certainly modified these percentages. Non-invasive imaging, in particular coronary multidetector computed tomography (MDCT), can help delineate the characteristics of the CTO. With coronary MDCT the occluded segment can be better delineated, calcium more reliably detected and quantified, the tortuosity and vessel path followed, the true length of the lesion better defined

Aim and Objectives

The objectives of this study were:

1. To study the clinical profile of patients undergoing Chronic Total Occlusion (CTO) angioplasty at our center over the past two years.
2. To assess the immediate outcomes of these patients following the procedure.

Study Design

This was a record-based descriptive study conducted using patient data collected in the CTO registry at our institution.

Study Setting

The study was conducted in the Department of Cardiology, Government Medical College, Alappuzha. Data were obtained from the CTO registry maintained in the Cardiac Catheterization Laboratory (Cath Lab).

Study Period

The study was conducted over a two-year period, from November 2022 to November 2024.

Inclusion Criteria

Patients were included in the study based on the following criteria:

1. Individuals aged 18 years or older.
2. Patients who were considered candidates for percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG).
3. Presence of a chronic total occlusion in a coronary artery confirmed by angiography, persisting for at least three months.

Exclusion Criteria

Patients were excluded from the study if they had any of the following:

1. Severe comorbidities, such as significant renal, hepatic, or pulmonary diseases that could increase procedural risk.
2. Uncontrolled systemic conditions like poorly controlled diabetes mellitus or hypertension.
3. Inability to provide informed consent, due to cognitive impairment or other communication barriers.

Study Procedure

All patients who fulfilled the inclusion criteria and did not meet any exclusion criteria were enrolled in the study. Data were collected retrospectively from the CTO registry, which included detailed records of patient demographics, clinical history, risk factors, and angiographic characteristics.

Data Analysis

The collected data were systematically compiled into a master chart. Variables of interest included presenting symptoms, comorbidities, lesion location, prior revascularization history, and procedural success or complications. Statistical analysis was performed using descriptive methods to summarize the clinical profile and immediate procedural outcomes.

The study was conducted by analyzing the CTO register maintained in the Department of Cardiology. A total of 220 cases were reviewed from the record , Most patients were elderly, with 66.36% aged 60 years and above. The cohort was predominantly male (84.09%). Hypertension and diabetes were common comorbidities, present in 76.36% and 86.36% respectively. A significant proportion also had a history of smoking (67.27%) and dyslipidemia (61.81%). Notably, 50.90% had undergone previous PCI, while 15.45% had a history of CABG. Chronic kidney disease and cerebrovascular accidents were relatively less common. Peripheral arterial disease was noted in more than half the patients. (Table 1)

Table 1: Baseline patient profile

The majority of patients presented with dyspnoea on exertion (83.18%), primarily in NYHA functional class II (50.9%), followed by easy fatigability (79.09%) and effort angina (71.36%). Exertional palpitations were also reported in 40.45% of patients. There were no patients in NYHA class IV, indicating that most cases were symptomatic but not in advanced heart failure.(Table 2)

Table 2: Patient clinical profile

Among the cardiac presentations, the most common was UA/NSTEMI, seen in 55.45% of the patients, followed by chronic stable angina (37.27%). STEMI was less frequently observed, accounting for 7.27% of the cases, indicating a predominance of non-ST elevation presentations. (Table 3)

Table 3: Table Baseline cardiac profile

Angiographic Characteristics and Procedural Details

Double vessel disease (69.54%) was the most common angiographic finding, followed by triple vessel disease (17.27%). LAD was the most commonly involved vessel with CTO (52.72%), followed by LCX (39.54%) and RCA (38.18%). Procedural success was achieved in 82.72% of cases, reflecting good outcomes despite complex anatomy. (Fig 1and 2)

The most frequent complication was coronary perforation, seen in 15.45% of patients, followed by nonfatal myocardial infarctions (10.45%) and arrhythmias (8.18%). No-flow or slow-flow phenomenon occurred in 8.18% of cases. Mortality rates, both all-cause and cardiac-specific, were low at 0.91%. Stroke and acute renal failure were rare. Importantly, no patient required immediate CABG, reflecting effective procedural management despite a moderate complication profile. (Table 4)

Table 4: Procedural and In-Hospital Outcomes

This single-centre observational study included 220 patients undergoing CTO-PCI, with a male predominance and a mean age of 66.4 years. The overall procedural success rate was 82.72%. A meta-analysis by Patel et al.⁹ of 65 studies involving 18,061 patients and 18,941 target CTO vessels showed an angiographic success rate of 77%. More recent studies employing modern techniques have reported procedural success rates exceeding 80%¹⁰ ¹¹. Our study findings are consistent with these trends, reflecting the impact of evolving techniques and operator expertise.

In our cohort, the highest success rate was observed in the left anterior descending (LAD) artery, followed by the right coronary artery (RCA), with the lowest in the left circumflex (LCX) artery. The routine use of advanced hardware such as microcatheters and dedicated CTO guidewires contributed significantly to the overall procedural success.

Immediate procedural outcomes were largely influenced by operator experience, optimal guidewire selection, and appropriate hardware usage. The most frequent periprocedural complications included minor coronary perforations, arrhythmias, access site complications, stroke, and a few non-fatal myocardial infarctions. The Japanese CTO registry reported a coronary perforation rate of 7.2%¹², while Mehran et al.¹³ documented coronary perforation and residual dissection rates of 7.4%.

All procedures were performed via femoral access, with a majority requiring bilateral femoral access. Access site complications included perforations, retroperitoneal hematomas (RPH), and pseudoaneurysms. Most perforations were minor and managed conservatively with heparin reversal and local compression. Two major perforations required balloon tamponade, covered stent deployment, and blood transfusion. Pseudoaneurysms of the common femoral artery were observed in a few cases; most were managed with ultrasound-guided compression, while one case necessitated surgical excision and arterial repair.

Previous studies have suggested that complications during CTO-PCI may influence post-procedural mortality. However, our study did not assess long-term outcomes, which are crucial for understanding the relationship between immediate complications and future adverse events.

Study Limitations

This study primarily focused on immediate procedural outcomes following CTO-PCI. However, follow-up data are essential to evaluate symptom relief, improvement in quality of life (QoL), and the incidence of major adverse cardiovascular events (MACE). A subsequent longitudinal study is planned to explore these long-term outcomes and correlate them with procedural success, failure, and complication rates.

In this single-centre study, the procedural success rate of CTO-PCI was over 80%, which is consistent with recent literature and reflects the impact of improved operator expertise, advanced techniques, and the use of specialized hardware. The highest success was observed in lesions involving the LAD, followed by RCA and LCX. Immediate complications were predominantly minor coronary perforations, access site issues, and arrhythmias. While these findings are encouraging, they emphasize the importance of operator skill and appropriate hardware selection in optimizing outcomes. Long-term follow-up is needed to assess symptom relief, quality of life, and the incidence of major adverse cardiovascular events.

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