Version May 2024
INTRODUCTION — Patients referred for coronary angiography are frequently found to have CTO of one or more coronary arteries. CTO may occur in isolation or in conjunction with important stenoses in other coronary arteries. For these patients, most of whom have failed medical therapy for angina management, there is uncertainty of the benefit of percutaneous coronary intervention (PCI) for CTO, and there are significant technical complexities and lower success rates with the procedure.
This topic will give our approach to issues surrounding the use of PCI for CTO in patients with stable angina pectoris and who have unacceptable symptoms while receiving maximal medical therapy. (See "Chronic coronary syndrome: Indications for revascularization" and "Revascularization in patients with stable coronary artery disease: Coronary artery bypass graft surgery versus percutaneous coronary intervention".)
DEFINITIONS — CTO is defined as a 100 percent stenosis of a coronary artery with Thrombolysis In Myocardial Infarction (TIMI) 0 flow (table 1) for more than three months (based on angiography or symptoms) [1]. Severe (but not total) occlusions with impaired flow are often referred to as "functional" CTOs, but such lesions are often technically less challenging to address percutaneously given the presence of an antegrade channel [2]. This topic will focus on "true" CTOs.
A broad group of experts from North America and Europe, including academicians, researchers, and practicing physicians, comprise the Coronary Artery Chronic Total Occlusion Academic Research Consortium. They released a consensus recommendations document in early 2021; it includes procedural definitions among other components [3].
PREVALENCE — CTOs are highly prevalent among patients undergoing diagnostic coronary angiography, where they are found in roughly one-quarter to one-third of patients, though the prevalence is related to the group studied [4-8]. Patients with a history of coronary artery bypass graft surgery are found to have CTOs of their native vessels more frequently (54 percent), while patients presenting with ST-elevation myocardial infarction (STEMI) are less likely to have a CTO (10 percent) [5,9]. (See "Primary percutaneous coronary intervention in acute ST elevation myocardial infarction: Determinants of outcome" and "Acute coronary syndromes: Approach to nonculprit lesions" and "Primary percutaneous coronary intervention in acute ST-elevation myocardial infarction: Periprocedural management".)
The right coronary artery is more frequently (55 to 65 percent) involved than the left anterior descending or circumflex arteries [8,10].
INDICATIONS FOR CORONARY INTERVENTION — We recommend percutaneous coronary intervention (PCI) for two groups of patients who are receiving optimal medical therapy: those for whom coronary artery bypass graft surgery offers a survival advantage but who cannot undergo this form of revascularization, and those who are dissatisfied with their quality of life due to symptoms or medication side effects. In patients who do not meet either criterion, we recommend a trial of optimal medical therapy prior to considering PCI. (See "Chronic coronary syndrome: Indications for revascularization", section on 'Indications'.)
High-quality evidence to suggest that CTO PCI can improve survival does not exist. Thus, the principal indication is to improve symptoms [11,12].
CLINICAL ASSOCIATIONS — CTO is most often diagnosed in patients referred for coronary angiography and possible revascularization due to angina refractory to medical therapy or diagnostic testing suggestive of myocardial ischemia. In addition to causing symptoms, CTOs are associated with a worse overall prognosis, with higher rates of death and non-fatal adverse cardiovascular events in several populations. Patients with CTOs tend to be older and have more comorbidities and greater impairment of left ventricular function [4-6]. Furthermore, patients with unrevascularized CTOs have been found to have higher mortality (adjusted hazard ratio [HR] 1.35; 95% CI 1.14-1.59) and a higher risk of major adverse cardiovascular events (MACE) including death and myocardial infarction (adjusted HR 1.14; 95% CI 0.92-1.41) compared with patients with multivessel coronary artery disease who are completely revascularized [13,14].
With regard to patients with acute coronary syndrome (ACS), most studies have excluded patients with CTO. The following observations have been made:
●The Acute Catheterization and Urgent Intervention Triage Strategy (ACUITY) Trial included patients who presented with non ST-elevation ACS who had a CTO as a nonculprit lesion and showed that those patients had higher MACE at one year as compared with those who were completely revascularized (25.9 versus 22.2 percent, respectively) [15].
●An analysis of the HORIZONS-AMI study showed higher three-year mortality in patients who present with STEMI and three-vessel disease with at least one CTO as compared with patients with STEMI with three-vessel coronary artery disease without CTO (19.4 versus 7 percent; HR 2.97; 95% CI 1.84-4.8) [9]. Patients who present with STEMI and a CTO in a non-infarct-related artery have higher 30-day mortality (HR 3.6; 95% CI 2.6 to 4.7) [16].
PREPROCEDURAL STEPS — Prior to percutaneous coronary intervention (PCI), we review the indication for revascularization, choose between PCI or coronary artery bypass graft surgery (CABG), and have a full discussion with the patient of the benefits and risks.
Indications — Stable angina or anginal equivalent (such dyspnea on exertion) refractory to optimal medical therapy, as well as the presence of a large ischemic area, are the most common indications for consideration of revascularization for CTO [17,18]. (See "Chronic coronary syndrome: Indications for revascularization".)
In addition, there should be a reasonable likelihood of success with an acceptable degree of risk.
Percutaneous coronary intervention versus coronary artery bypass graft surgery — In patients who meet usual criteria for referral for CABG, the presence of CTO does not influence that decision. (See "Revascularization in patients with stable coronary artery disease: Coronary artery bypass graft surgery versus percutaneous coronary intervention", section on 'Our approach'.)
In CTO patients who otherwise meet criteria for PCI, such as those with single-vessel disease, our choice between PCI and CABG is determined in part by which coronary artery includes the CTO.
We favor PCI over CABG in patients who have single-vessel disease of the right or left circumflex coronary artery, as well as those who have had a prior CABG with a patent left internal mammary graft (LIMA). We carefully evaluate patients with single-vessel disease of the left anterior descending artery (LAD) and often prefer CABG given the durability of the LIMA compared with CTO PCI. However, we recommend CTO PCI to patients with shorter CTOs (to allow future LIMA touchdown when needed) and when PCI is unlikely to jeopardize significant branches (ie, as can occur with dissection re-entry). It is imperative to integrate the risks and benefits based on the degree of the patient's symptoms, anatomical factors, the operator's experience affecting the likelihood of successful procedure, the risk for complications, and patient preferences. (See "Revascularization in patients with stable coronary artery disease: Coronary artery bypass graft surgery versus percutaneous coronary intervention".)
Among patients with multivessel disease and one or more CTOs, any of the following favor CABG [19]:
●Left main disease.
●Complex three-vessel disease, particularly in patients with insulin-requiring diabetes, severe left ventricular dysfunction, or chronic kidney disease.
●An occluded proximal LAD that supplies a viable anterior wall that is not favorable for PCI.
●Multiple CTOs with a low anticipated rate of success.
Other patients can be managed by PCI with the goal being complete revascularization if possible. The nonoccluded vessels should be stented first (if indicated) if it is likely that ischemia in these territories may be responsible for the patient’s symptoms and there is a low anticipated rate of complications. In contrast, PCI should usually be performed first on the CTO if failed PCI of this lesion would lead to referral for CABG.
Informed consent — We have an extensive discussion about risks and benefits of CTO PCI with the patient. In patients with a history of MI with low left ventricular ejection fraction (LVEF), we may consider viability study before CTO PCI. Ischemic mitral regurgitation is another indication that we sometimes consider (usually circumflex artery). We carefully review the films, and based on risk scores and our center's experience, we incorporate the likelihood of technical success and risk of complications in our discussions with the patient. We are careful that the patient is aware of the absence of demonstrated benefit of CTO PCI to improve mortality or MI rates, as many patients are motivated by a belief that an open vessel will lead to improved longevity. Based on our discussion, many patients opt to continue medical therapy alone, while others, typically the most symptomatic, opt to pursue CTO PCI.
PROCEDURAL SUCCESS — CTOs are challenging lesions to approach using percutaneous coronary intervention (PCI). The success rate, defined as achieving <50 percent stenosis with TIMI 3 flow, has been very low (50 to 70 percent) compared with non-CTO PCI (approximately 95 percent) [20-22]. However, technical advances have increased the success rate without increasing rates of complications [23]. Studies report a success rate of 85 to 90 percent in experienced centers [24-28]. In contrast, a study including all operators independent of specific CTO expertise has reported a success rate of 59 percent [23]. For this reason, it is estimated that as few as 8 to 15 percent of patients with CTOs undergo PCI [23,29-31].
Predictors of technical failure — Demographic and angiographic predictors of technical failure have been identified [26,32].
Demographic predictors include dialysis, a history of MI, prior revascularization (either coronary artery bypass graft surgery or PCI), prior stoke/transient ischemic attack, peripheral artery disease, heart failure, and age >75 years [33]. Angiographic predictors include CTO length >15 mm, saphenous vein graft, tortuous vessel, >45 degree bending, moderate to severe calcification, ostial location of the CTO, and a blunt stump. A distal vessel that is >2.0 mm in diameter, has little disease, and has no major branches generally facilitates CTO recanalization [11].
In addition, low-volume operators (<50 CTO PCI cases per year) have a lower procedural success rate as compared with high-volume operators [27]. High-volume centers have higher use of the retrograde approach with similar complication rates and higher success rates [27,34]. In a single-center study, the establishment of a coordinated CTO program with two operators scrubbed in each procedure and procedural protocols was followed by improvement in outcomes [35].
Risk prediction scoring systems — Many of the risk predictors discussed directly above have been integrated in several scores used to predict technical success. The following are two commonly used models:
●The Multicenter Chronic Total Occlusion Registry in Japan (J-CTO) is broadly used to describe CTO complexity and likelihood of procedural success [36]. This score, which predicts the likelihood of crossing the lesion within 30 minutes, includes five factors each worth one point when present: occlusion length ≥20 mm, blunt stump appearance of the proximal cap of the occlusion, calcification within the lesion segment, the presence of a >45 degree bend within the CTO, and prior failed PCI attempt of the lesion. A J-CTO score of 0 is considered easy, score of 1 intermediate, 2 difficult, and ≥3 very difficult, with the probability of crossing within 30 minutes found to be 87.7, 67.1, 42.2, and 10 percent, respectively. The probability of a technically successful procedure was 97.8, 92.3, 88.4, and 73.3 percent, respectively [36].
●The Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS-CTO) score uses four independent variables to predict the likelihood of successful opening of a CTO: ambiguous proximal cap of the CTO (inability to discern precise location of vessel course), moderate or severe tortuosity, circumflex artery target CTO vessel, and lack of "interventional collaterals" to support a retrograde procedure [37]. The number of patients with a PROGRESS-CTO score ≥3 in the study was very low. Overall, the likelihood of success with a PROGRESS-CTO score of 0 was 91.3 percent, a score of 1 was 73.9 percent, a score of 2 was 56.5 percent, and a score of ≥3 was very low (<4.3 percent). The PROGRESS-CTO score performed similarly to the J-CTO in predicting success, apart from lower complexity lesions where J-CTO had better discrimination.
OUTCOMES — Successful percutaneous coronary intervention (PCI) of CTO is associated with improvement in anginal symptomatology. However, there does not appear to be improvement in rates of all-cause mortality, MI, stroke, and repeat revascularization.
Most studies evaluating the impact of PCI on outcomes among patients with CTO have been observational single-center or multicenter registries. In addition, a large proportion of the available outcome research studies were performed before several modern practice-changing techniques were available. Thus, the overall body of literature supporting CTO PCI does not provide strong evidence to inform the impact of modern CTO PCI on outcomes.
Angina relief and quality of life — Multiple observational studies have demonstrated improvement in angina and quality of life in patients with successful CTO PCI [38-40]. The 2017 Outcomes, Patient Health Status, and Efficiency in Chronic Total Occlusion Hybrid Procedures (OPEN-CTO) Registry found that among the 1000 individuals undergoing CTO PCI, patients with successful CTO PCI showed significant improvement at one month in the Seattle Angina Questionnaire with quality-of-life scores of 10.8 points (p<001) as compared with those patients who had an unsuccessful CTO PCI [41]. Similarly, there was a significantly higher reduction in mean Rose Dyspnea Scale score, which decreased (improved) more in patients with successful CTO PCI than in patients with unsuccessful procedures (p<0.001) [41].
The EuroCTO Trial found improvement in the health status of patients with angina who underwent CTO PCI. In this trial, 396 individuals were randomly assigned (2:1) to PCI or optimal medical therapy (OMT) [42]. At 12 months, a greater improvement in the Seattle Angina Questionnaire subscale of angina frequency was observed with PCI than with OMT (p = 0.003). A second trial that randomly assigned 834 patients to OMT or CTO PCI showed no significant improvement in Seattle Angina Questionnaire subscale of angina frequency [43]. Limitations of this trial include the fact that half of the patients in each arm underwent non-CTO PCI after randomization, 20 percent of patients in the OMT arm underwent CTO PCI within three days of randomization, and the trial did not achieve expected power due to poor enrollment goals.
The COMET-CTO study of 100 patients randomly assigned to CTO PCI or OMT measured quality of life (assessed by Seattle angina questionnaire) at baseline and during a mean follow-up of 275 ± 88 days [44]. In patients assigned to CTO PCI, quality of life improved by over 20 points (scores range from 0 to 100), whereas for those assigned to OMT, there was no improvement.
Among 1000 consecutive patients who underwent CTO PCI in a 12-center registry, baseline quality of life (assessed by Seattle angina questionnaire) improved by an average of 36 at one year (scores range from 0 to 100) [45]. Similarly, an observational study in China showed that CTO PCI improved quality of life as assessed by a 12‐Item short‐form health survey questionnaire at one month and one year among patients of all ages, including those >75 years of age [46].
Major adverse cardiac events (MACE) — Elective CTO PCI using drug-eluting stents has not been shown to prevent all-cause mortality, myocardial infarction (MI), or stroke, though there may be a short-term benefit on reducing target lesion revascularization. This is not surprising given the absence of a clear benefit of elective PCI for MACE in non-CTO populations. (See "Chronic coronary syndrome: Indications for revascularization", section on 'Patients with high-risk anatomy'.)
A meta-analysis examined CTO PCI versus optimal medical therapy on all-cause mortality, cardiovascular mortality, MI, and target vessel revascularization outcomes [47]. The study included six randomized controlled trials of 1890 patients. Half of the lesions were in the right coronary artery with an average SYNTAX score of 21.4 ± 10.
This meta-analysis found that pooled rates of all-cause mortality, cardiovascular mortality, and MI were similar among patients who received CTO PCI compared with optimal medical therapy, although confidence intervals were wide and did not exclude an effect:
●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).
●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).
●MI (one-year RR 1.01, 95% CI 0.43-2.36 and four-year RR 1.46, 95% CI 0.75-2.87).
However, the CTO PCI group had fewer target lesion revascularization at one but not at four years, compared with patients in the optimal medical therapy group (one-year RR 0.28, 95% CI 0.17-0.49) and (four-year RR 0.55 95% CI 0.28-1.09). Limitations of this analysis included relatively few one-year mortality and MI events and presence of high heterogeneity for some outcomes (eg, all-cause mortality and target vessel revascularization at four years).
Prior analyses of large registries and other observational data had provided mixed evidence in support of PCI; however, these are limited in their ability to infer a causal association between PCI and improved outcomes, given the inherent and unmeasured differences between patients more likely to have successful procedures versus those with failed procedures [2,21,39,48-52].
Left ventricular ejection fraction — Small observational studies have suggested some improvement in LVEF after CTO PCI. A study from the Netherlands showed marginal improvement in ejection fraction from 60±9 to 63±11 percent by cardiac magnetic resonance imaging at five months after successful CTO PCI [53]. However, the majority of the patients had preserved LVEF prior to CTO PCI. Conversely, a trial including 72 patients with LVEF <35 percent undergoing successful CTO PCI showed improvement in LVEF from 29.1±3.4 to 41.6±7.9 percent (p<0.001) at six months [54].
Evaluating Xience and Left Ventricular Function in Percutaneous Coronary Intervention on Occlusions After ST-Elevation Myocardial Infarction (EXPLORE) was a randomized trial that evaluated the role of non-culprit CTO PCI within seven days of index presentation with STEMI versus no CTO PCI and showed no difference in LVEF or left ventricular end diastolic volume by cardiac magnetic resonance imaging after four months of index procedure [55]. However, the CTO PCI success rate in this study was low (77 percent) as compared with that reported in other centers, and sicker patients (shock, requiring implantable cardioverter-defibrillator, etc) were excluded.
TECHNICAL ASPECTS OF CTO PCI — Once the indications for CTO percutaneous coronary intervention (PCI) have been reviewed and the risk-benefit ratio has been discussed with the patient, there are several aspects of CTO PCI that differ from routine PCI. (See 'Preprocedural steps' above.)
First, extensive evaluation of the diagnostic coronary angiogram is encouraged in order to understand the characteristics of the proximal cap of the occlusion, the true occlusion length, the distal vessel quality and presence of important side branches, and the adequacy and course of collaterals. Second, two arterial access points are routinely used to enable simultaneous injections, one of the occluded vessel and the other of the collateral supplying vessel(s). Third, the operator should be facile with rapidly switching among several techniques and strategies [10,11,56].
In all cases, we use a microcatheter for optimal guidewire manipulation and exchange.
We prefer antegrade techniques when possible, given the higher likelihood of complications with retrograde procedures. Thus, we routinely start most cases with antegrade wire escalation and if we enter the subintimal space (dissection), we move to antegrade dissection re-entry (ADR) if the distal vessel is suitable for this approach and there is low risk of side branch compromise. Parallel wiring (adding a second antegrade wire) using a dual-lumen catheter is also often effective if the CTO is relatively short and straight. In patients who have good interventional collaterals, we would consider retrograde approach when antegrade wiring fails or if there is proximal cap ambiguity that might render an antegrade approach risky. Lastly, we would use a more aggressive form of subintimal tracking and reentry that creates a large dissection plane as a "bailout" strategy. In this case, we prefer not to deploy any stents given a high-likelihood of restenosis (approximately 50 percent) and thus we prefer a "re-look" coronary angiogram in six to eight weeks in which we usually stent once the artery has had time to heal.
For patients who have a bifurcation of the coronary artery very close to the distal cap and who have interventional collaterals, we would start the case with antegrade wire escalation (AWE) if the proximal cap is unambiguous and moves rapidly to retrograde approach if our antegrade wire goes into the subintimal space given that propagation of dissection past the distal cap would block flow to one of the branches of the bifurcation. Similarly, we would move faster to retrograde when the distal vessel is not a good target for re-entry (small or heavily calcified vessel).
In terms of access, our default strategy is to use a biradial approach to decrease the risk of vascular complications and bleeding (7F antegrade and 6F retrograde most often).
Antegrade techniques — Techniques that approach the CTO from the proximal side of the occlusion are considered to be "antegrade" techniques.
●AWE is usually the initial strategy for short CTOs in which the vessel course and origin of the occlusion are well defined. It consists of advancing wires with different degrees of stiffness, coating, and maneuverability through the true lumen of the vessel and then dilating with devices and balloons before proceeding with stenting.
●ADR includes several techniques in which wires and/or devices travel through the vessel wall (subintimal space) instead of the lumen and then re-access the true lumen past the occlusion with either specialized wiring technique (limited antegrade subintimal tracking) or specialized devices that enable true luminal reentry.
Retrograde techniques — Techniques that involve approaching the CTO from the distal end of the occlusion via collaterals or previously placed bypass grafts are considered to be "retrograde" techniques. Wiring through native vessel collaterals, commonly through the septal perforators but also through epicardial collaterals, typically involves delivering a soft wire through a collateral vessel to the target vessel distal to the total occlusion supported by a maneuverable microcatheter (image 1).
●Retrograde wire escalation involves advancing a wire to the distal cap. Then a sequential advancement of wires with different degrees of stiffness through the true lumen of the vessel can be performed similarly to the antegrade wire escalation. Retrograde true luminal wiring, particularly in short occlusions, may be more straightforward than antegrade luminal wiring when the proximal cap of the occlusion is ambiguous or severely calcified.
●Retrograde dissection reentry is used in complex lesions when retrograde wires are not able to be advanced across the occlusion in the true luminal space. The most common retrograde techniques that involve subintimal passage of wires are variants of what is termed "controlled antegrade and retrograde tracking" (CART). CART procedures involve inflating a balloon to enlarge the false luminal area to allow for a common space for antegrade and retrograde wires to meet, and to create a passageway between the false and true lumen. Most commonly, "reverse CART" is performed in which a balloon is inserted over a wire that passes from the proximal true lumen and into the subintimal space within the CTO and is inflated. Subsequently, a retrograde wire in the common subintimal space is then advanced following the pathway created by the antegrade balloon inflation, and ultimately into the antegrade guide or guide extension catheter. The retrograde wire can be externalized out of the body through the antegrade guide, and PCI can be performed over this wire. Retrograde techniques can improve the success rate of CTO programs and operators but are associated with a higher rate of complications [57,58].
COMPLICATIONS AND OUTCOMES — The complications of CTO percutaneous coronary intervention (PCI) are similar to those of routine PCI but occur more frequently. The higher complication rate should factor into the decision of whether to proceed with PCI. (See 'Preprocedural steps' above and "Periprocedural complications of percutaneous coronary intervention".)
A large analysis of the National Cardiovascular Data Registry in the United States showed higher in-hospital major adverse cardiovascular event (MACE) frequency (1.6 versus 0.8 percent; p<0.001), mortality (0.4 versus 0.3 percent; p<0.001), stroke (0.1 versus 0.1 percent; p = 0.045), tamponade (0.3 versus 0.1 percent; p<0.001), MI (2.7 versus 1.9 percent; p<0.001), and need for packed red blood cell transfusion (2.7 versus 1.9 percent; p<0.001) in 22,365 patients who underwent CTO PCI compared with 572,145 patients who underwent non-CTO PCI [23].
In a meta-analysis of 65 contemporary studies with 18,061 patients, the pooled estimated rate was MACE 3.1 percent, death 0.1 percent, need for emergent coronary artery bypass graft surgery 0.1 percent, stroke 0.1 percent, type 4 MI 2.8 percent, coronary perforation 3.2 percent, tamponade 0.5 percent, and contrast-induced nephropathy 1.2 percent [58]. Failed CTO PCI carries a higher complication rate [23]. Most studies have not included consecutive CTO PCI patients or had systematic and adjudicated capture of complications, and may thus underestimate the true risks of CTO PCI.
The OPEN-CTO Registry, which included 1000 consecutive patients (not highly selected) from 12 high-volume CTO PCI centers found the following in-hospital complication rates: MACE 7 percent, death 0.9 percent, MI 2.6 percent, stroke 0 percent, significant Ellis grade ≥3 perforation (3.3 percent), bleeding requiring treatment (0.3 percent), and acute kidney injury (0.7 percent) [41].
On average, contrast volume is greater and fluoroscopy time is longer with PCI of a CTO than a non-CTO lesion.
LONG-TERM OUTCOMES, INCLUDING NEED FOR REPEAT VASCULARIZATION — Most studies examining the long-term patency of CTO percutaneous coronary intervention (PCI) were performed with first-generation drug-eluting stents (DES) [59-62] . A study including 1226 consecutive patients who underwent CTO PCI at three high-volume PCI centers showed a target vessel revascularization (TVR) rate of 17 percent five years after implantation of a DES (most of them first generation) [61]. A study that used more modern DES platforms that included 223 patients undergoing CTO PCI with antegrade techniques showed TVR rates between 3.1 and 15.5 percent at 24 months (depending on the crossing technique used) [63]. Data from randomized trials have shown similar revascularization rates. For example, in a study of 1184 consecutive patients who underwent CTO PCI and were randomized to a DES versus bare metal stent (BMS), the five-year TVR-free survival rate was 81.6 and 73.5 percent (log-rank p<0.001) in the two groups, respectively [60]; similarly, in a cohort including 991 procedures in three large-volume centers using modern DES, the TVR was 9.4 percent with a median follow-up of 1.2 years [64].
Long-term outcomes after CTO PCI were compared with non-CTO PCI in the National Cardiovascular Data Registry. CTO PCI was associated with a slightly higher risk of long-term repeat revascularization compared with non-CTO PCI (adjusted hazard ratio [aHR] 1.09; 95% CI 1.05-1.13). However, compared with high-risk non-CTO PCIs (including saphenous vein graft and unprotected left main PCI or PCI requiring atherectomy), CTO PCI was associated with a slightly lower risk of long-term MACE (aHR 0.87; 95% CI 0.84-0.90) and readmission (aHR 0.87; 95% CI 0.84-0.90) [65].
There appear to be differences in TVR rates based on the different CTO PCI techniques. A study with 223 patients undergoing CTO PCI using antegrade dissection re-entry (see 'Antegrade techniques' above) techniques in four high-volume CTO PCI centers described a TVR as low as 3.1 percent using modern reentry devices [63] while other studies using different techniques have reported a TVR of 52.4 percent [66]. This wide variability in TVR is a reflection of the differences in CTO PCI techniques and differences in procedural characteristics, and points to the need for large population-based studies evaluating long-term patency of CTO PCI.
OUR APPROACH — We generally use the following sequential approach to CTO PCI:
●We recommend that in most cases, CTO PCI should not be done in the same procedure as the first diagnostic angiogram, that is, ad hoc CTO PCI should be avoided. This allows time for a careful discussion of potential risks and benefits of the procedure with the patient, and dedicated time to review the anatomy and potential approach in detail. (See 'Complications and outcomes' above.)
●We carefully review the patient's history and angiogram to make sure that PCI is a reasonable choice. (See 'Indications' above.)
●We allow the patient to participate in decision making. (See 'Informed consent' above.)
●In our institutions, we refer the patient to interventionalists who are highly skilled in CTO PCI (a CTO team).
●We choose a technical approach that includes multiple contingencies if the initial selected approach fails. (See 'Technical aspects of CTO PCI' above.)
RECOMMENDATIONS OF OTHERS — The American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions give a weak recommendation to proceed with CTO percutaneous coronary intervention (PCI) in patients with a clinical indication and suitable anatomy when performed by an experienced operator [67].
The 2018 European Society of Cardiology/European Association for Cardio-Thoracic Surgery guideline on myocardial revascularization states that indications for CTO PCI are similar to those for non-CTO [68].
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Chronic coronary syndrome" and "Society guideline links: Coronary artery bypass graft surgery".)
SUMMARY AND RECOMMENDATIONS
●Prevalence – CTO is highly prevalent in patients with symptomatic coronary artery disease. (See 'Prevalence' above.)
●Indications – CTO percutaneous coronary intervention (PCI) should be considered in patients with disabling angina despite treatment with optimal medical therapy in whom there is a reasonable chance of technical success with an acceptable risk. Complications during CTO PCI, though not prohibitive, occur more frequently than in routine PCI. (See 'Indications' above and 'Complications and outcomes' above.)
●Outcomes – Successful CTO PCI is associated with improvement in anginal symptomatology. However, there does not appear to be improvement in rates of all-cause mortality, myocardial infarction (MI), stroke, and long-term repeat revascularization. There may be a short-term benefit for revascularization in the first year following CTO PCI. (See 'Outcomes' above.)
●Technical aspects – We prefer to start with antegrade techniques when possible, given the higher likelihood of complications with retrograde procedures. However, operators performing CTOs should feel comfortable with switching quickly between approaches to maximize the probability of success and reducing the risk of complications. (See 'Technical aspects of CTO PCI' above.)
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