Chronic total occlusive disease (CTO) percutaneous coronary intervention (PCI) has made significant progress in recent years, with indications, patency strategies, imaging and complications Disease management has been improved. Randomized controlled trials and prospective registry studies have provided high-quality data on the risks and benefits of CTO PCI. Through global cooperation, consensus on terminology, indications, research endpoints and clinical trial design principles has been reached, and global consensus documents such as the CTO Academic Research Alliance have been formed. This intractable disease can be managed systematically and incrementally by increasing the use of preoperative coronary CT angiography (CCTA) and intraoperative intravascular imaging, as well as by developing new techniques, approaches to patency, and complication management strategies.
This review comprehensively discusses and summarizes the indications, preoperative planning, opening strategies, complications of CTO PCI Management, timing of discontinuation and future direction.
At a Glance: ➤The primary indication for CTO PCI is symptom relief (including angina, respiratory Difficulty and depression), improve quality of life and physical function, reduce ischemia. ➤It is recommended to carry out careful preoperative planning and use a systematic lesion opening strategy to improve the success rate of CTO PCI. ➤Intravascular imaging can promote CTO recanalization and improve long-term outcomes.
➤Systematic management of complications can minimize adverse effects.
< strong>Incidence and treatment status
In patients with coronary artery disease (CAD) on angiography, CTO accounts for 16%-20%. Despite the high prevalence of CTO, CTO recanalization represents only a small fraction of all PCI procedures and may be associated with low success rates, high complication rates, long procedure times, high costs, and a lack of clinical benefit perceived by clinicians . In the past decade, the volume of CTO PCI procedures has gradually increased, and the success rate of the procedure has also increased (from 45%-56% to 55%-62%), while the complication rate has not changed significantly.
Indications p>
Retrospective studies suggest that CTO recanalization may provide patient benefits, including angina relief, improved quality of life and exercise tolerance, reduced ischemic burden, left ventricular function and ventricular Improved remodeling, fewer arrhythmias, and even improved survival. However, most of these studies compared patients with successful and unsuccessful CTO PCI procedures, and there was selection bias.
The results of several randomized controlled trials and prospective registry studies were recently published, among which the DECISION-CTO study The results obtained were inconclusive, limited by premature study termination, low surgical success rates, selection bias, and significant crossover between the optimal medical therapy (OMT) group and the CTO PCI group. The EuroCTO study demonstrated angina relief and improved quality of life in patients who received CTO PCI plus OMT compared with patients who received OMT alone. The OPEN-CTO study showed that angina pectoris and quality of life were improved in patients with successful surgery compared with those before CTO PCI.
In conclusion, in appropriately selected patients, CTO PCI was associated with angina, dyspnea, quality of life, depression However, whether CTO PCI can improve hard clinical outcomes remains to be determined by further studies. The ISCHEMIA-CTO study will enroll more than 1,500 asymptomatic patients with myocardial ischemia ≥10% to compare the efficacy of CTO PCI and OMT in reducing major cardiovascular and cerebrovascular adverse events. The results are expected to be published after 2028.
Preoperative Planning strong>
Meticulous preoperative planning is the key to the success of CTO PCI, which mainly includes the following aspects: ➤Perform diagnostic angiography to identify as many collateral vessels as possible;➤assess the complexity of occlusive lesions (including proximal fibrous caps, calcifications, tortuosity, lesion length, distal fibers vascular bifurcation at the cap, distal vascular quality, and availability of collateral vessels); ➤Plan for vascular access and guide catheter support; ➤Determine patency Strategies (Positive wire patency vs. Positive subintimal reentry vs. reverse technique);
➤Assess whether the patient requires mechanical circulatory support.
CTO opening strategy strong>
CTO opening techniques mainly include positive guide wire opening (AW), positive subendometrial reentry True lumen (ADR), retrograde wire opening (RW) and retrograde subintimal return to true lumen (RDR).
1. Hybrid strategy
The Hybrid strategy proposed in 2012 was the first strategy to use a combination of various techniques to open CTO, advocating the determination of the initial CTO opening strategy (AW, ADR, and reverse technique) by routine bilateral angiographic evaluation, and the rapid conversion from the failed opening strategy. for other techniques to maximize surgical success, efficiency, and safety (as shown in Figure 2).
Figure 2 Hybrid strategy
2. Asia Pacific CTO Club Strategy
The Asia Pacific CTO Club PCI strategy proposed in 2017 recommends the use of preoperative Proximal fibrous cap puncture guided by CT angiography (CTA) and intraoperative intravascular ultrasound (IVUS). In the case of extraplaque tracking, this strategy recommends the use of parallel guidewire techniques, IVUS-guided reentry to the true lumen, or a retrograde technique (as shown in Figure 3). Figure 3 Asia Pacific CTO Club Strategy
European proposal in 2019 The CTO Club strategy recommends the use of a parallel guidewire technique and ADR (preferably the Stingray system) in the event of failure of the orthopedic guidewire. This strategy recommends the use of scratch-and-go, balloon-assisted subintimal entry (BASE), and IVUS-guided proximal fibrous cap puncture. to resolve the blurring of the proximal fibrous cap (as shown in Figure 4). In addition, a new concept of “investment technology” was introduced.
Figure 4 European CTO Club Strategy
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4. Japanese CTO PCI Expert Strategy
An alternative strategy was proposed by the Japanese panel in 2019 (shown in Figure 5), suggesting direct inverse techniques in the case of complex occlusive lesions, while scoring 0 for in-stent CTO and J-CTO occlusive lesions, the forward technique is preferred. In addition, it is recommended to switch to a retrograde technique or try a more advanced forward technique (parallel wire, ADR, or IVUS-guided return to the true lumen) after 20 minutes of procedure time.
Figure 5 Japan CTO
Although there are subtle differences between the above four strategies, they all follow similar principles. CTO experts from five continents summarized seven key principles of CTO PCI, as shown in Table 1.
Table 1 Global Guidelines for CTO PCI
Intravascular Imaging< /span>
Reliable evidence shows the incidence of major adverse cardiovascular events in IVUS-guided CTO PCI compared with angiography-guided CTO PCI alone Reduced, long-term follow-up restenosis rate decreased. IVUS is the preferred intravascular imaging method for CTO PCI, which is not only highly penetrating, but also does not require injection of contrast agents and will not enlarge the dissection. Optical coherence tomography (OCT), on the other hand, requires injection of a contrast agent to flush out the blood flow, which can lead to dissection enlargement, so this imaging technique has limited use in CTO PCI.
CTO PCI complications< /strong>
CTO PCI complications can be divided into cardiac and non-cardiac complications. In addition, cardiac complications can be further divided into coronary and non-coronary complications, as shown in Table 2.
Table 2 CTO PCI complications
Among them, hypotension is the most common complication, and the management strategy is shown in Figure 6.
Management strategies for low blood pressure /p>
Syndromes characterized by “ST-segment shift, chest pain, and ischemia” are also common complications, and management strategies are shown in the figure 7 is shown.
Fig 7
The management strategy for device loss/fracture is shown in Figure 8.
Fig.8 Management strategy for device loss/fracture
PCI stop timing
< /p>When the following conditions occur and there is no obvious progress in the operation, the surgeon should consider terminating PCI:(1) The operation time is more than 3 hours; (2) ) Contrast agent dosage > 3 times estimated glomerular filtration rate (eGFR); (3) radiation dose > 5 Gy (Air Kerma).
In addition, discontinuation of CTO PCI should also be considered when patient or operator fatigue occurs.
Future Directions strong>
The future development of CTO PCI has 4 main directions, including new equipment, new technology, research and training of clinicians. Several new ortho-guide wire opening aids have recently emerged, such as the Soundbite medical opening system and ReCross (IMDS). Due to the high technical level required for reverse opening and the high risk of complications, the development of new technologies should focus on streamlining AW.
References: Azzalini L, Karmpaliotis D, Santiago R, et al. Contemporary Issues in Chronic Total Occlusion Percutaneous Coronary Intervention. JACC Cardiovasc Interv. 2022 Jan 10;15(1):1-21. doi: 10.1016/j.jcin.2021.09.027. PMID: 34991814.