Ostial right coronary artery lesion morphology and outcomes after treatment with drug-eluting stents.

BACKGROUND: Outcomes after percutaneous coronary intervention (PCI) for de novo ostial right coronary artery (RCA) lesions are poor. AIMS: We used intravascular ultrasound (IVUS) to clarify the morphological patterns of de novo ostial RCA lesions and their associated clinical outcome. METHODS: Among 5,102 RCA IVUS studies, 170 de novo ostial RCA stenoses (within 3 mm from the aorto-ostium) were identified. These were classified as 1) isolated ostial lesions (no disease extending beyond 10 mm from the ostium and without a calcified nodule [CN]); 2) ostial CN, typically with diffuse disease (disease extending beyond 10 mm); and 3) ostial lesions with diffuse disease but without a CN. The primary outcome was target lesion failure (TLF: cardiac death, target vessel myocardial infarction, definite stent thrombosis, and ischaemia-driven target lesion revascularisation). RESULTS: The prevalence of an isolated ostial lesion was 11.8% (n=20), 47.6% (n=81) were ostial CN, and 40.6% (n=69) were ostial lesions with diffuse disease. Compared to ostial lesions with diffuse disease, isolated lesions were more common in women (75.0% vs 42.0%; p=0.01), and CN were associated with older age (median [first, third quartile] 76 [70, 83] vs 69 [63, 81] years old; p=0.002). The Kaplan-Meier rate of TLF at 2 years was significantly higher in patients with CN (21.6%) compared to diffuse lesions (8.2%) (p=0.04), and patients with isolated lesions had no events. A multivariable Cox proportional hazard model revealed that CN were significantly associated with TLF (hazard ratio 6.63, 95% confidence interval: 1.28-34.3; p=0.02). CONCLUSIONS: Ostial RCA lesions have specific morphologies - detectable by IVUS - that may be associated with long-term clinical outcomes.

Comprehensive Management of ANOCA, Part 1-Definition, Patient Population, and Diagnosis: JACC State-of-the-Art Review.

Angina with nonobstructive coronary arteries (ANOCA) is increasingly recognized and may affect nearly one-half of patients undergoing invasive coronary angiography for suspected ischemic heart disease. This working diagnosis encompasses coronary microvascular dysfunction, microvascular and epicardial spasm, myocardial bridging, and other occult coronary abnormalities. Patients with ANOCA often face a high burden of symptoms and may experience repeated presentations to multiple medical providers before receiving a diagnosis. Given the challenges of establishing a diagnosis, patients with ANOCA frequently experience invalidation and recidivism, possibly leading to anxiety and depression. Advances in scientific knowledge and diagnostic testing now allow for routine evaluation of ANOCA noninvasively and in the cardiac catheterization laboratory with coronary function testing (CFT). CFT includes diagnostic coronary angiography, assessment of coronary flow reserve and microcirculatory resistance, provocative testing for endothelial dysfunction and coronary vasospasm, and intravascular imaging for identification of myocardial bridging, with hemodynamic assessment as needed.

Comprehensive Management of ANOCA, Part 2-Program Development, Treatment, and Research Initiatives: JACC State-of-the-Art Review.

Centers specializing in coronary function testing are critical to ensure a systematic approach to the diagnosis and treatment of angina with nonobstructive coronary arteries (ANOCA). Management leveraging lifestyle, pharmacology, and device-based therapeutic options for ANOCA can improve angina burden and quality of life in affected patients. Multidisciplinary care teams that can tailor and titrate therapies based on individual patient needs are critical to the success of comprehensive programs. As coronary function testing for ANOCA is more widely adopted, collaborative research initiatives will be fundamental to improve ANOCA care. These efforts will require standardized symptom assessments and data collection, which will propel future large-scale clinical trials.

Mechanisms and treatment outcomes of ostial right coronary artery in-stent restenosis.

BACKGROUND: Despite a high rate of in-stent restenosis (ISR) after stenting the right coronary artery (RCA) ostium, the mechanism of ostial RCA ISR is not well understood. AIMS: We aimed to clarify the cause of ostial RCA ISR using intravascular ultrasound (IVUS). METHODS: Overall, 139 ostial RCA ISR lesions were identified with IVUS, pre-revascularisation. Primary ISR mechanisms were classified as follows: 1) neointimal hyperplasia (NIH); 2) neoatherosclerosis; 3) ostium not covered by the stent; 4) stent fracture or deformation; 5) stent underexpansion (old minimum stent area <4.0 mm2 or stent expansion <50%); or 6) a protruding calcified nodule. RESULTS: The median duration from prior stenting was 1.2 (first quartile 0.6, third quartile 3.1) years. The primary mechanisms of ISR were NIH in 25% (n=35) of lesions, neoatherosclerosis in 22% (n=30), uncovered ostium in 6% (n=9) (biological cause 53%, n=74), stent fracture or deformation in 25% (n=35), underexpansion in 11% (n=15), and protruding calcified nodules in 11% (n=15) (mechanical cause 47%, n=65). Including secondary mechanisms, 51% (n=71) of ostial RCA ISRs had stent fractures that were associated with greater hinge motion of the ostial-aorta angle during the cardiac cycle. The Kaplan-Meier rate of target lesion failure at 1 year was 11.5%. When the mechanically caused ISRs were treated without new stents, they suffered a higher subsequent event rate (41.4%) compared with non-mechanical causes or mechanical causes treated without restenting (7.8%, unadjusted hazard ratio 6.44, 95% confidence interval: 2.33-17.78; p<0.0001). CONCLUSIONS: Half of the ostial RCA ISRs were due to mechanical causes. Subsequent event rates were high, especially in mechanically caused ISRs treated without the implantation of a new stent.

Impact of Nonobstructive Left Main Coronary Artery Atherosclerosis on Long-Term Mortality.

BACKGROUND: Although the presence of severe stenosis in the left main coronary artery (LMCA) is a well-established predictor of mortality, whether this extends to nonobstructive atherosclerosis in the LMCA is unknown. OBJECTIVES: The aim of this study was to evaluate the association between LMCA disease by intravascular ultrasound (IVUS) and long-term mortality. METHODS: Between 2005 and 2013, 3,239 patients with LMCA IVUS imaging without LMCA revascularization (either before angiography or scheduled based on index angiography or IVUS) were included. The primary and secondary endpoints were all-cause and cardiac mortality at a minimum of 5 years obtained from the National Death Index. RESULTS: The IVUS-measured LMCA minimum lumen area (MLA) and plaque burden were 13.1 ± 5.0 mm2 and 41.7% ± 15.6%, respectively. The median follow-up was 8.2 years. The Kaplan-Meier estimated 12-year all-cause and cardiac death rates were 37.5% and 17.0%, respectively. Greater plaque burden (unadjusted HR per 10%: 1.17; 95% CI: 1.12-1.22; P < 0.0001) and smaller IVUS MLA (unadjusted HR per 1 mm2: 0.98; 95% CI: 0.96-0.99; P = 0.0008) were associated with all-cause death. After adjusting for clinical, angiographic, and IVUS factors, plaque burden (adjusted HR per 10%: 1.12; 95% CI: 1.04-1.21; P = 0.003) but not MLA (adjusted HR per 1 mm2: 1.02; 95% CI: 0.99-1.04; P = 0.18) was associated with long-term all-cause death. These findings were also consistent for long-term cardiac mortality. CONCLUSIONS: In the present large-scale study with a 12-year follow-up, increasing LMCA plaque burden was associated with long-term all-cause and cardiac mortality in patients not undergoing LMCA revascularization, even when the lumen area was preserved.

Safety of Provocative Testing With Intracoronary Acetylcholine and Implications for Standard Protocols.

BACKGROUND: Heterogeneity in diagnostic criteria and provocation protocols has posed challenges in understanding the safety of coronary provocation testing with intracoronary acetylcholine (ACh) for the contemporary diagnosis of epicardial and microvascular spasm. OBJECTIVES: We examined the safety of testing and subgroup differences in procedural risks based on ethnicity, diagnostic criteria, and provocation protocols. METHODS: PubMed and Embase were searched in November 2021 to identify original articles reporting procedural complications associated with intracoronary ACh administration. The primary outcome was the pooled estimate of the incidence of major complications including death, myocardial infarction, ventricular tachycardia/fibrillation, and shock. RESULTS: A total of 16 studies with 12,585 patients were included in the meta-analysis. The overall pooled estimate of the incidence of major complications was 0.5% (95% CI: 0.0%-1.3%) without any reports of death. Exploratory subgroup analyses revealed that the pooled incidence of major complications was significantly higher in the studies that followed the contemporary diagnosis criteria for epicardial spasm defined as ≥90% diameter reduction (1.0%; 95% CI: 0.3%-2.0%) but significantly lower in Western populations (0.0%; 95% CI: 0.0%-0.45%). The rate of positive epicardial spasm and the incidence of major complications were similar between provocation protocols using the maximum ACh doses of 100 µg and 200 µg. CONCLUSIONS: Intracoronary ACh administration for the contemporary diagnosis of epicardial and microvascular spasm is a safe procedure. Moreover, excellent safety records are observed in Western populations primarily presenting with myocardial ischemia and/or infarction with nonobstructive coronary arteries. This study will help standardize ACh testing to improve clinical diagnosis and ensure procedural safety.

Percutaneous Axillary Access for Placement of Microaxial Ventricular Support Devices: The Axillary Access Registry to Monitor Safety (ARMS).

BACKGROUND: There has been increasing utilization of short-term mechanical circulatory support devices for a variety of clinical indications. Many patients have suboptimal iliofemoral access options or reasons why early mobilization is desirable. Axillary artery access is an option for these patients, but little is known about the utility of this approach to facilitate short-term use for circulatory support with microaxial pump devices. METHODS: The Axillary Access Registry to Monitor Safety (ARMS) was a prospective, observational multicenter registry to study the feasibility and acute safety of mechanical circulatory support via percutaneous upper-extremity access. RESULTS: One hundred and two patients were collected from 10 participating centers. Successful device implantation was 98% (100 of 102). Devices were implanted for a median of 2 days (interquartile range, 0-5 days; range, 0-35 days). Procedural complications included 10 bleeding events and 1 stroke. There were 3 patients with brachial plexus-related symptoms all consisting of C8 tingling and all arising after multiple days of support. Postprocedural access site hematoma or bleeding was noted in 9 patients. Device explantation utilized closure devices alone in 61%, stent grafts in 17%, balloon tamponade facilitated closure in 15%, and planned surgical explant in 5%. Duration of support appeared to be independently associated with a 1.1% increased odds of vascular complication per day ([95% CI, 0.0%-2.3%] P=0.05). CONCLUSIONS: Percutaneous axillary access for use with microaxial support pumps appears feasible with acceptable rates of bleeding despite early experience. Larger studies are necessary to confirm the pilot data presented here.

Appropriate Use Criteria and Health Status Outcomes Following Chronic Total Occlusion Percutaneous Coronary Intervention: Insights From the OPEN-CTO Registry.

BACKGROUND: The American College of Cardiology/American Heart Association Appropriate Use Criteria were designed to aid clinical decision-making, yet their association with health status outcomes after chronic total occlusion percutaneous coronary intervention (PCI) is unknown. METHODS: We analyzed 769 patients with baseline and 1-year health status data after chronic total occlusion PCI. Procedures were categorized as appropriate, may be appropriate, or rarely appropriate. Mean changes in patient-reported health status, assessed by the Seattle Angina Questionnaire (SAQ), were compared across appropriate use criteria categories from baseline to 1 year. Change in SAQ summary score was stratified as little to no benefit (≤10 points), intermediate (10-19 points), large (20-29 points), and very large (≥30 points). RESULTS: The appropriate use criteria indication was appropriate in 573 patients (74.5%), may be appropriate in 191 (24.8%), and rarely appropriate in 5 (0.7%). Patients in the appropriate group reported greater improvement in SAQ summary scores (27.3±21.3 points) at 1 year compared with the may be appropriate (22.5±20.9; P=0.01). A similar pattern was noted for SAQ angina frequency (mean change 24.0±27.2 versus 18.7±25.6; P=0.02). The appropriate group had the highest proportion of very large improvements in SAQ summary scores (44.5% versus 33.3%; P=0.01). CONCLUSIONS: Among patients undergoing chronic total occlusion PCI, the rate of rarely appropriate PCI was low. The rate of appropriate PCI was high and was associated with the greatest health status improvement at 1 year. A substantial proportion of patients in the may be appropriate group experienced meaningful health status benefits as well.

Nonemergent Percutaneous Coronary Intervention on an Unprotected Left Main Coronary Artery Supported with Impella® Heart Pump in Patients Ineligible for Surgical Revascularization.

OBJECTIVES: We sought to assess if ineligibility to coronary artery bypass grafting (CABG) constitutes a risk factor in patients who underwent a nonemergent unprotected left main coronary artery (ULMCA) percutaneous coronary intervention (PCI) with prophylactic Impella® heart pump support. BACKGROUND: ULMCA PCI in patients not deemed eligible for CABG is associated with significantly worse outcomes compared to ULMCA PCI in eligible patients. METHODS: Patients from the cVAD Registry and the PROTECT II trial who underwent a nonemergent ULMCA PCI were identified. We compared in-hospital mortality and major adverse cardiac and cerebrovascular event (MACCE) rates as well as 30-day survival and MACCE rates between CABG ineligible and CABG eligible patients. RESULTS: A total of 331 patients were included (293 Impella 2.5®, 38 Impella CP®); 227 were ineligible for CABG and 104 were eligible. Baseline characteristics were remarkable for a trend toward higher rate of chronic obstructive pulmonary disease in the ineligible patients. In-hospital mortality (3.52% vs. 5.77%; p=0.383) and MACCE (6.61% vs. 7.69%; p=0.816) rates as well as 30-day survival (92.0% vs. 93.4%; Log-Rank p-value =0.781) and MACCE (88.1% vs. 90.1%; Log-Rank p-value=0.648) rates were not different between the two groups. CONCLUSIONS: The results of our study suggest that prophylactic Impella support appears to mitigate the risks inherent to surgical ineligibility in patients undergoing a nonemergent ULMCA PCI. Our results require further investigation.

De-escalation of antianginal medications after successful chronic total occlusion percutaneous coronary intervention: Frequency and relationship with health status.

BACKGROUND: Successful chronic total occlusion (CTO) percutaneous coronary intervention (PCI) can markedly reduce angina symptom burden, but many patients often remain on multiple antianginal medications (AAMs) after the procedure. It is unclear when, or if, AAMs can be de-escalated to prevent adverse effects or limit polypharmacy. We examined the association of de-escalation of AAMs after CTO PCI with long-term health status. METHODS: In a 12-center registry of consecutive CTO PCI patients, health status was assessed at 6 months after successful CTO PCI with the Seattle Angina Questionnaire and the Rose Dyspnea Scale. Among patients with technical CTO PCI success, we examined the association of AAM de-escalation with 6-month health status using multivariable models adjusting for revascularization completeness and predicted risk of post-PCI angina (using a validated risk model). We also examined predictors and variability of AAMs de-escalation. RESULTS: Of 669 patients with technical success of CTO PCI, AAMs were de-escalated in 276 (35.9%) patients at 1 month. Patients with AAM de-escalation reported similar angina and dyspnea rates at 6 months compared with those whose AAMs were reduced (any angina: 22.5% vs 20%, P = .43; any dyspnea: 51.8% vs 50.1%, P = .40). In a multivariable model adjusting for complete revascularization and predicted risk of post-PCI angina, de-escalation of AAMs at 1 month was not associated with an increased risk of angina, dyspnea, or worse health status at 6 months. CONCLUSIONS: Among patients with successful CTO PCI, de-escalation of AAMs occurred in about one-third of patients at 1 month and was not associated with worse long-term health status.

The effectiveness of excimer laser angioplasty to treat coronary in-stent restenosis with peri-stent calcium as assessed by optical coherence tomography.

AIMS: We aimed to evaluate the effectiveness of excimer laser coronary angioplasty (ELCA) to treat in-stent restenosis (ISR) due to peri-stent calcium-related stent underexpansion as assessed by optical coherence tomography (OCT). METHODS AND RESULTS: We studied 81 patients (81 lesions with ISR, stent underexpansion, and peri-stent calcium >90°) who underwent OCT imaging both pre and post percutaneous coronary intervention and compared lesions treated with ELCA (n=23) vs. without ELCA (n=58). ELCA use was associated with more calcium fracture (ELCA: 61%, non-ELCA: 12%, p<0.01), larger final minimum lumen area (ELCA: 4.76 mm2 [3.25, 5.57], non-ELCA: 3.46 mm2 [2.80, 4.13], p<0.01), and a larger previously implanted stent area (ELCA: 6.15 mm2 [4.83, 7.09], non-ELCA: 4.65 mm2 [3.84, 5.40], p<0.01). In the multivariable model, ELCA use was associated with peri-stent calcium fracture (odds ratio 46.5, 95% confidence interval: 6.8, 315.9, p<0.001) that, in turn, was associated with final larger lumen and stent dimensions. Finally, contrast injection during ELCA was associated with multiple calcium fractures and fractures even in thicker calcium. CONCLUSIONS: ELCA is effective for treating ISR with underexpansion by disrupting peri-stent calcium, facilitating better expansion of the previously implanted stent.

EC-VAD: Combined Use of Extracorporeal Membrane Oxygenation and Percutaneous Microaxial Pump Left Ventricular Assist Device.

Combination of venoarterial extracorporeal membrane oxygenation (VA-ECMO) and a percutaneous microaxial left ventricular assist device (pLVAD), or "EC-VAD," has been reported in cases of left ventricular decompression with mixed results. We conducted a retrospective review of patients who received EC-VAD (n = 29) or isolated VA-ECMO therapy (ECMO-only; n = 196) for refractory cardiogenic shock between February 2011 and October 2014. Fourteen patients received VA-ECMO and then Impella pLVAD (E→EC-VAD), and 15 received the Impella pump then VA-ECMO (I→EC-VAD). E→EC-VAD patients demonstrated decreased pulmonary artery systolic (36.00 ± 16.84 mm Hg versus 30.63 ± 12.13 mm Hg; p = 0.049) and diastolic (24.25 ± 13.45 mm Hg versus 17.25 ± 7.96 mm Hg, p = 0.049) pressures by 24 hours post-EC-VAD implant. In the same period, I→EC-VAD patients demonstrated improved SvO2 (43.14 ± 16.75% versus 75.18 ± 13.88%, p = 0.043) and PaO2/FiO2 ratio (148.55 ± 67.69 mm Hg versus 374.51 ± 170.97 mm Hg, p = 0.043). Thirty-day survival rates were 42.9% in E→EC-VAD, 46.7% in I→EC-VAD, and 49.0% in ECMO-only (p = 0.913). Hemolysis occurred more in EC-VAD patients (44.83% versus 17.35% in ECMO-only, p = 0.002); however, there was no increased frequency of other adverse events including bleeding and lower limb ischemia. Despite increased hemolysis, combined use of VA-ECMO and pLVAD may improve or circumvent left ventricular distension in refractory cardiogenic shock while promoting adequate blood flow.

Intravascular ultrasound analysis of intraplaque versus subintimal tracking in percutaneous intervention for coronary chronic total occlusions: One year outcomes.

OBJECTIVES: We sought to determine the 1-year outcomes of patients receiving successful chronic total occlusion (CTO) percutaneous coronary intervention (PCI) procedures comparing subintimal versus intraplaque wire tracking patterns. BACKGROUND: CTO PCI utilizes both intraluminal and subintimal wire tracking to achieve successful percutaneous revascularization. Intravascular ultrasound (IVUS) can be used to precisely determine the path of wire tracking. METHODS: From 2014 to 2016, data from patients undergoing CTO PCI were collected in a single-center database. The primary composite endpoint was target vessel failure (TVF) defined as cardiovascular death, target vessel myocardial infarction (MI), or target vessel revascularization (TVR). RESULTS: In total 157 patients with successful CTO PCI and concomitant IVUS imaging completed 1-year follow-up. Subintimal tracking was detected in 53.5% of cases and those patients had a higher incidence of prior PCI, prior coronary artery bypass grafting, and higher J-CTO score. At 1-year, the unadjusted rate of TVF in the subintimal tracking group was higher than the intraplaque group (17.9 vs. 6.9%, HR 2.74, 95% CI 1.00-7.54, P = 0.04), driven by numerically higher rates of TVR and peri-procedural MI. After multivariable adjustment, no significant differences in the rates of the TVF between subintimal vs. intraplaque groups were present at 1-year (TVF: HR 1.51, 95% CI 0.38-6.00, P = 0.55). Landmark analysis excluding in-hospital events showed no significant differences in TVF to 1-year. CONCLUSIONS: IVUS-detected subintimal tracking was observed in over half of successful CTO PCI cases and correlated with baseline and angiographic factors that contributed to the overall rate of TVF at 1-year.

A sex stratified outcome analysis from the OPEN-CTO registry.

INTRODUCTION: Women have been under-represented in trials. Due to the dearth of information about CTO-PCI in women and discordance of previous results, sex differences in outcomes in the OPEN-CTO Trial were investigated. METHODS: OPEN-CTO is an investigator-initiated, multicenter, prospective observational registry of consecutive CTO patients undergoing PCI at 12 U.S. centers. The one-year outcomes of this trial stratified by sex were examined. Optimal propensity matching was performed to compare outcomes between sexes. Multivariate conditional logistic regression modeling for predictors of procedural success was performed. RESULTS: Women represented 19.6% of the cohort (196/1,000 patients). Women were more likely to report dyspnea as their predominant symptom. Women reported statistically worse physical limitation and poorer quality of life as compared to men. J-CTO scores were similar in males and females. Technical, procedural success and MACE rates were similar in both sexes. Contrast and radiation doses were however significantly lower in women. The SAQ- summary score, RDS, EQ-5D VAS, PHQ-8 scores were all improved to the same degree at 1 year in women as compared to men. Predictors of procedural success revealed that younger age, lower J-CTO score and absence of prior CABG were predictors of procedural success. Sex did not predict procedural success or 1-year MACE in this regression model. CONCLUSION: This real-world registry revealed that women derive the same benefit from CTO-PCI as men without additional complications and with favorable health status outcomes at 1 year. Consideration of revascularization by PCI in symptomatic women should be considered as part of the treatment when appropriate.

Bifurcation and ostial optical coherence tomography mapping (BOOM) - Case description of a novel bifurcation stent technique.

Stent placement guided by angiography alone is often inexact, but of increased importance with bifurcation percutaneous coronary intervention (PCI). We describe a novel technique using optical coherence tomography (OCT)-guided angiographic co-registration termed "Bifurcation and Ostial OCT Mapping" (BOOM). The technique is based on the precise identification and mapping of the side-branch ostium using co-registration to minimize protrusion of stent struts into the main branch while ensuring full coverage of the ostium in the side-branch.

Association of Stress Test Risk Classification With Health Status After Chronic Total Occlusion Angioplasty (from the Outcomes, Patient Health Status and Efficiency in Chronic Total Occlusion Hybrid Procedures [OPEN-CTO] Study).

Stress testing is endorsed by the American College of Cardiology/American Heart Association Appropriate Use Criteria to identify appropriate candidates for Chronic Total Occlusion (CTO) Percutaneous Coronary Intervention (PCI). However, the relation between stress test risk classification and health status after CTO PCI is not known. We studied 449 patients in the 12-center OPEN CTO registry who underwent stress testing before successful CTO PCI, comparing outcomes of patients with low-risk (LR) versus intermediate to high-risk (IHR) findings. Health status was assessed using the Seattle Angina Questionnaire Angina Frequency (SAQ AF), Quality of Life (SAQ QoL), and Summary Scores (SAQ SS). Stress tests were LR in 40 (8.9%) and IHR in 409 (91.1%) patients. There were greater improvements on the SAQ AF (LR vs IHR 14.2 ± 2.7 vs 23.3 ± 1.3 points, p <0.001) and SAQ SS (LR vs IHR 20.8 ± 2.3 vs 25.4 ± 1.1 points, p = 0.03) in patients with IHR findings, but there was no difference between groups on the SAQ QoL domain (LR vs IHR 24.8 ± 3.4 vs 27.3 ± 1.6 points, p = 0.42). We observed large health status improvements after CTO PCI in both the LR and IHR groups, with the greatest reduction in angina among those with IHR stress tests. Although patients with higher risk studies may experience greater reduction in angina symptoms, on average, patients with LR stress tests also experienced large improvements in symptoms after CTO PCI, suggesting patients with refractory symptoms should be considered appropriate candidates for CTO PCI regardless of stress test findings.

Dyspnea Among Patients With Chronic Total Occlusions Undergoing Percutaneous Coronary Intervention: Prevalence and Predictors of Improvement.

BACKGROUND: Dyspnea is a common angina equivalent that adversely affects quality of life, but its prevalence in patients with chronic total occlusions (CTOs) and predictors of its improvement after CTO percutaneous coronary intervention (PCI) are unknown. We examined the prevalence of dyspnea and predictors of its improvement among patients selected for CTO PCI. METHODS AND RESULTS: In the OPEN CTO registry (Outcomes, Patient health status, and Efficiency iN Chronic Total Occlusion) of 12 US experienced centers, 987 patients undergoing CTO PCI (procedure success 82%) were assessed for dyspnea with the Rose Dyspnea Scale at baseline and 1 month after CTO PCI. Rose Dyspnea Scale scores range from 0 to 4 with higher scores indicating more dyspnea with common activities. A total of 800 (81%) reported some dyspnea at baseline with a mean (±SD) Rose Dyspnea Scale of 2.8±1.2. Dyspnea improvement was defined as a ≥1 point decrease in Rose Dyspnea Scale from baseline to 1 month. Predictors of dyspnea improvement were examined with a modified Poisson regression model. Patients with dyspnea were more likely to be female, obese, smokers, and to have more comorbidities and angina. Among patients with baseline dyspnea, 70% reported less dyspnea at 1 month after CTO PCI. Successful CTO PCI was associated with more frequent dyspnea improvement than failure, even after adjustment for other clinical variables. Anemia, depression, and lung disease were associated with less dyspnea improvement after PCI. CONCLUSIONS: Dyspnea is a common symptom among patients undergoing CTO PCI and improves significantly with successful PCI. Patients with other potentially noncardiac causes of dyspnea reported less dyspnea improvement after CTO PCI.