Prevalence and anatomical factors associated with stent under-expansion in non-severely calcified lesions.

BACKGROUND: Stent underexpansion, typically related to lesion calcification, is the strongest predictor of adverse events after percutaneous coronary intervention (PCI). Although uncommon, underexpansion may also occur in non-severely calcified lesions. AIM: We sought to identify the prevalence and anatomical characteristics of underexpansion in non-severely calcified lesions. METHODS: We included 993 patients who underwent optical coherence tomography-guided PCI of 1051 de novo lesions with maximum calcium arc <180°. Negative remodeling (NR) was the smallest lesion site external elastic lamina diameter that was also smaller than the distal reference. Stent expansion was evaluated using a linear regression model accounting for vessel tapering; underexpansion required both stent expansion <70% and stent area <4.5mm2. RESULTS: Underexpansion was observed in 3.6% of non-heavily calcified lesions (38/1051). Pre-stent maximum calcium arc and thickness were greater in lesions with versus without underexpansion (median 119° vs. 85°, p = 0.002; median 0.95 mm vs. 0.78 mm, p = 0.008). NR was also more common in lesions with underexpansion (44.7% vs. 24.5%, p = 0.007). In the multivariable logistic regression model, larger and thicker eccentric calcium, mid left anterior descending artery (LAD) location, and NR were associated with underexpansion in non-severely calcified lesions. The rate of underexpansion was especially high (30.7%) in lesions exhibiting all three morphologies. Two-year TLF tended to be higher in underexpanded versus non-underexpanded stents (9.7% vs. 3.7%, unadjusted hazard ratio [95% confidence interval] = 3.02 [0.92, 9.58], p = 0.06). CONCLUSION: Although underexpansion in the absence of severe calcium (<180°) is uncommon, mid-LAD lesions with NR and large and thick eccentric calcium were associated with underexpansion.

Optical Coherence Tomography-Based Functional Stenosis Assessment: FUSION-A Prospective Multicenter Trial.

BACKGROUND: Intravascular imaging and intracoronary physiology may both be used to guide and optimize percutaneous coronary intervention; however, they are rarely used together. The virtual flow reserve (VFR) is an optical coherence tomography (OCT)-based model of fractional flow reserve (FFR) facilitating the assessment of the physiological significance of coronary lesions. We aimed to validate the VFR assessment of intermediate coronary artery stenoses. METHODS: FUSION (Validation of OCT-Based Functional Diagnosis of Coronary Stenosis) was a multicenter, prospective, observational study comparing OCT-derived VFR to invasive FFR. VFR was mathematically derived from a lumped parameter flow model based on 3-dimensional lumen morphology. Patients undergoing coronary angiography with intermediate angiographic stenosis (40%-90%) requiring physiological assessment were enrolled. Investigational sites were blinded to the VFR analysis, and all OCT and FFR data were reviewed by an independent core laboratory. The coprimary end points were the sensitivity and specificity of VFR against FFR as the reference standard, each of which was tested against prespecified performance goals. RESULTS: After core laboratory review, 266 vessels in 224 patients from 25 US centers were included in the analysis. The mean angiographic diameter stenosis was 65.5%±14.9%, and the mean FFR was 0.83±0.11. Overall accuracy, sensitivity, and specificity of VFR versus FFR using a binary cutoff point of 0.80 were 82.0%, 80.4%, and 82.9%, respectively. The 97.5% lower confidence bound met the prespecified performance goal for sensitivity (71.6% versus 70%; P=0.01) and specificity (76.6% versus 75%; P=0.01). The area under the curve was 0.88 (95% CI, 0.84-0.92; P<0.0001). CONCLUSIONS: OCT-derived VFR demonstrates high sensitivity and specificity for predicting invasive FFR. Integrating high-resolution intravascular imaging with imaging-derived physiology may provide synergistic benefits as an adjunct to percutaneous coronary intervention. REGISTRATION: URL: https://clinicaltrials.gov; Unique identifier: NCT04356027.

Impact of Incomplete Revascularization After PCI in Left Main Disease: The EXCEL Trial.

BACKGROUND: The importance of complete revascularization after percutaneous coronary intervention (PCI) in patients with left main coronary artery disease is uncertain. We investigated the clinical impact of complete revascularization in patients with left main coronary artery disease undergoing PCI in the EXCEL trial (Evaluation of XIENCE Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization). METHODS: Composite rates of death or myocardial infarction (MI) following PCI during 5-year follow-up were examined in 903 patients based on core laboratory definitions of anatomic and functional complete revascularization, residual SYNTAX score (The Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery), and residual Jeopardy Score (rJS). RESULTS: The risk of death or MI did not vary based on anatomic, functional, or residual SYNTAX score complete revascularization but did differ according to the rJS (5-year rates 17.6%, 19.5%, and 38.9% with rJS 0, 2, and ≥4, respectively; P=0.006). The higher rate of death or MI with rJS≥4 versus rJS≤2 was driven conjointly by increased mortality (adjusted hazard ratio, 2.29 [95% CI, 1.11-4.71]; P=0.02) and spontaneous MI (adjusted hazard ratio, 2.89 [95% CI, 1.17-7.17]; P=0.02). The most common location for untreated severe stenoses in the rJS≥4 group was the left circumflex artery (LCX), and the post-PCI absence, compared with the presence, of any untreated lesion with diameter stenosis ≥70% in the LCX was associated with reduced 5-year rates of death or MI (18.9% versus 35.2%; hazard ratio, 0.48 [95% CI, 0.32-0.74]; P<0.001). The risk was the highest for residual ostial/proximal LCX lesions. CONCLUSIONS: Among patients undergoing PCI in EXCEL trial, incomplete revascularization according to the rJS was associated with increased rates of death and spontaneous MI. Post-PCI untreated high-grade lesions in the LCX (especially the ostial/proximal LCX) drove these outcomes. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01205776.

Intravascular imaging-guided coronary drug-eluting stent implantation: an updated network meta-analysis.

BACKGROUND: Previous meta-analyses have shown reduced risks of composite adverse events with intravascular imaging-guided percutaneous coronary intervention (PCI) compared with angiography guidance alone. However, these studies have been insufficiently powered to show whether all-cause death or all myocardial infarction are reduced with intravascular imaging guidance, and most previous intravascular imaging studies were done with intravascular ultrasound rather than optical coherence tomography (OCT), a newer imaging modality. We aimed to assess the comparative performance of intravascular imaging-guided PCI and angiography-guided PCI with drug-eluting stents. METHODS: For this systematic review and updated meta-analysis, we searched the MEDLINE, Embase, and Cochrane databases from inception to Aug 30, 2023, for studies that randomly assigned patients undergoing PCI with drug-eluting stents either to intravascular ultrasound or OCT, or both, or to angiography alone to guide the intervention. The searches were done and study-level data were extracted independently by two investigators. The primary endpoint was target lesion failure, defined as the composite of cardiac death, target vessel-myocardial infarction (TV-MI), or target lesion revascularisation, assessed in patients randomly assigned to intravascular imaging guidance (intravascular ultrasound or OCT) versus angiography guidance. We did a standard frequentist meta-analysis to generate direct data, and a network meta-analysis to generate indirect data and overall treatment effects. Outcomes were expressed as relative risks (RRs) with 95% CIs at the longest reported follow-up duration. This study was registered with the international prospective register of systematic reviews (PROSPERO, number CRD42023455662). FINDINGS: 22 trials were identified in which 15 964 patients were randomised and followed for a weighted mean duration of 24·7 months (longest duration of follow-up in each study ranging from 6 to 60 months). Compared with angiography-guided PCI, intravascular imaging-guided PCI resulted in a decreased risk of target lesion failure (RR 0·71 [95% CI 0·63-0·80]; p<0·0001), driven by reductions in the risks of cardiac death (RR 0·55 [95% CI 0·41-0·75]; p=0·0001), TV-MI (RR 0·82 [95% CI 0·68-0·98]; p=0·030), and target lesion revascularisation (RR 0·72 [95% CI 0·60-0·86]; p=0·0002). Intravascular imaging guidance also reduced the risks of stent thrombosis (RR 0·52 [95% CI 0·34-0·81]; p=0·0036), all myocardial infarction (RR 0·83 [95% CI 0·71-0·99]; p=0·033), and all-cause death (RR 0·75 [95% CI 0·60-0·93]; p=0·0091). Outcomes were similar for OCT-guided and intravascular ultrasound-guided PCI. INTERPRETATION: Compared with angiography guidance, intravascular imaging guidance of coronary stent implantation with OCT or intravascular ultrasound enhances both the safety and effectiveness of PCI, reducing the risks of death, myocardial infarction, repeat revascularisation, and stent thrombosis. FUNDING: Abbott.

Presence and Relevance of Myocardial Bridge in LAD-PCI of CTO and Non-CTO Lesions.

BACKGROUND: Intravascular ultrasound (IVUS) studies show that one-quarter of left anterior descending (LAD) arteries have a myocardial bridge. An MB may be associated with stent failure when the stent extends into the MB. OBJECTIVES: The aim of this study was to investigate: 1) the association between an MB and chronic total occlusion (CTO) in any LAD lesions; and 2) the association between an MB and subsequent clinical outcomes after percutaneous coronary intervention in LAD CTOs. METHODS: A total of 3,342 LAD lesions with IVUS-guided percutaneous coronary intervention (280 CTO and 3,062 non-CTO lesions) were included. The primary outcome was target lesion failure (cardiac death, target vessel myocardial infarction, definite stent thrombosis, and ischemic-driven target lesion revascularization). RESULTS: An MB by IVUS was significantly more prevalent in LAD CTOs than LAD non-CTOs (40.4% [113/280] vs 25.8% [789/3,062]; P < 0.0001). The discrepancy in CTO length between angiography and IVUS was greater in 113 LAD CTOs with an MB than 167 LAD CTOs without an MB (6.0 [Q1, Q3: 0.1, 12.2] mm vs 0.2 [Q1, Q3: -1.4, 8.4] mm; P < 0.0001). Overall, 48.7% (55/113) of LAD CTOs had a stent that extended into an MB after which target lesion failure was significantly higher compared to a stent that did not extend into an MB (26.3% vs 0%; P = 0.0004) or compared to an LAD CTO without an MB (26.3% vs 9.6%; P = 0.02). CONCLUSIONS: An MB was more common in LAD CTO than non-CTO LAD lesions. If present, approximately one-half of LAD CTOs had a stent extending into an MB that, in turn, was associated with worse outcomes.

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.

Intravascular Imaging-Guided Versus Angiography-Guided Percutaneous Coronary Intervention: A Systematic Review and Meta-Analysis of Randomized Trials.

BACKGROUND: Despite the initial evidence supporting the utility of intravascular imaging to guide percutaneous coronary intervention (PCI), adoption remains low. Recent new trial data have become available. An updated study-level meta-analysis comparing intravascular imaging to angiography to guide PCI was performed. This study aimed to evaluate the clinical outcomes of intravascular imaging-guided PCI compared with angiography-guided PCI. METHODS AND RESULTS: A random-effects meta-analysis was performed on the basis of the intention-to-treat principle. The primary outcomes were major adverse cardiac events, cardiac death, and all-cause death. Mixed-effects meta-regression was performed to investigate the impact of complex PCI on the primary outcomes. A total of 16 trials with 7814 patients were included. The weighted mean follow-up duration was 28.8 months. Intravascular imaging led to a lower risk of major adverse cardiac events (relative risk [RR], 0.67 [95% CI, 0.55-0.82]; P<0.001), cardiac death (RR, 0.49 [95% CI, 0.34-0.71]; P<0.001), stent thrombosis (RR, 0.63 [95% CI, 0.40-0.99]; P=0.046), target-lesion revascularization (RR, 0.67 [95% CI, 0.49-0.91]; P=0.01), and target-vessel revascularization (RR, 0.60 [95% CI, 0.45-0.80]; P<0.001). In complex lesion subsets, the point estimate for imaging-guided PCI compared with angiography-guided PCI for all-cause death was a RR of 0.75 (95% CI, 0.55-1.02; P=0.07). CONCLUSIONS: In patients undergoing PCI, intravascular imaging is associated with reductions in major adverse cardiac events, cardiac death, stent thrombosis, target-lesion revascularization, and target-vessel revascularization. The magnitude of benefit is large and consistent across all included studies. There may also be benefits in all-cause death, particularly in complex lesion subsets. These results support the use of intravascular imaging as standard of care and updates of clinical guidelines.

Rotational atherectomy combined with cutting balloon to optimise stent expansion in calcified lesions: the ROTA-CUT randomised trial.

BACKGROUND: Percutaneous coronary intervention (PCI) of calcified lesions remains challenging for interventionalists. AIMS: We aimed to investigate whether combining rotational atherectomy (RA) with cutting balloon angioplasty (RA+CBA) results in more optimal stent expansion compared with RA followed by non-compliant balloon angioplasty (RA+NCBA). METHODS: ROTA-CUT is a prospective, multicentre, randomised trial of 60 patients with coronary artery disease undergoing PCI of moderately or severely calcified lesions with drug-eluting stent implantation. Patients were randomised 1:1 to either RA+CBA or RA+NCBA. The primary endpoint was the minimum stent area on intravascular ultrasound (IVUS). Secondary endpoints included minimum lumen area and stent expansion assessed by IVUS and acute lumen gain, final residual diameter stenosis and minimum lumen diameter assessed by angiography. Clinical endpoints were obtained at 30 days. RESULTS: The mean age was 71.1±9.4 years, and 22% were women. The procedural details of RA were similar between groups, as were procedure duration and contrast use. Minimum stent area was similar with RA+CBA versus RA+NCBA (6.7±1.7 mm2 vs 6.9±1.8 mm2; p=0.685). Furthermore, there were no significant differences regarding the other IVUS and angiographic endpoints. Procedural complications were rare, and 30-day clinical events included 2 myocardial infarctions and 1 target vessel revascularisation in the RA+CBA group and 1 myocardial infarction in the RA+NCBA group. CONCLUSIONS: Combining RA with CBA resulted in a similar minimum stent area compared with RA followed by NCBA in patients undergoing PCI of moderately or severely calcified lesions. RA followed by CBA was safe with rare procedural complications and few clinical adverse events at 30 days.

Changes in post-PCI physiology based on anatomical vessel location: a DEFINE PCI substudy.

BACKGROUND: Anatomical vessel location affects post-percutaneous coronary intervention (PCI) physiology. AIMS: We aimed to compare the post-PCI instantaneous wave-free ratio (iFR) in left anterior descending (LAD) versus non-LAD vessels and to identify the factors associated with a suboptimal post-PCI iFR. METHODS: DEFINE PCI was a multicentre, prospective, observational study in which a blinded post-PCI iFR pullback was used to assess residual ischaemia following angiographically successful PCI. RESULTS: Pre- and post-PCI iFR recordings of 311 LAD and 195 non-LAD vessels were compared. Though pre-PCI iFR in the LAD vessels (median 0.82 [0.63, 0.86]) were higher compared with those in non-LAD vessels (median 0.72 [0.49, 0.84]; p<0.0001), post-PCI iFR were lower in the LAD vessels (median 0.92 [0.88, 0.94] vs 0.98 [0.95, 1.00]; p<0.0001). The prevalence of a suboptimal post-PCI iFR of <0.95 was higher in the LAD vessels (77.8% vs 22.6%; p<0.0001). While the overall frequency of residual physiological diffuse disease (31.4% vs 38.6%; p=0.26) and residual focal disease in the non-stented segment (49.6% vs 50.0%; p=0.99) were similar in both groups, residual focal disease within the stented segment was more common in LAD versus non-LAD vessels (53.7% vs 27.3%; p=0.0009). Improvement in iFR from pre- to post-PCI was associated with angina relief regardless of vessel location. CONCLUSIONS: After angiographically successful PCI, post-PCI iFR is lower in the LAD compared with non-LAD vessels, resulting in a higher prevalence of suboptimal post-PCI iFR in LAD vessels. This difference is, in part, due to a greater frequency of a residual focal pressure gradient within the stented segment which may be amenable to more aggressive PCI.

Impact of Calcium Eccentricity on the Safety and Effectiveness of Coronary Intravascular Lithotripsy: Pooled Analysis From the Disrupt CAD Studies.

BACKGROUND: Coronary intravascular lithotripsy (IVL) safely facilitates successful stent implantation in severely calcified lesions. This analysis sought to determine the relative impact of lesion calcium eccentricity on the safety and effectiveness of IVL using high-resolution optical coherence tomography imaging. METHODS: Individual patient-level data (n=262) were pooled from 4 distinct international prospective studies (Disrupt CAD I, II, III, and IV) and analyzed by an independent optical coherence tomography core laboratory. IVL performance in eccentric versus concentric calcification was analyzed by dividing calcified lesions into quartiles (≤180° [most eccentric], 181°-270°, 271°-359°, and 360° [concentric]) by maximum continuous calcium arc. RESULTS: In the 230 patients with clear imaging field on optical coherence tomography, there were no differences in preprocedure minimum lumen area, diameter stenosis, or maximum calcium thickness. The calcium length and volume index increased progressively with increasing mean and maximum continuous calcium arc (ie, concentricity). Conversely, the minimum calcium thickness decreased progressively with increasing concentricity. Post-procedure, the number of calcium fractures, fracture depth, and fracture width increased with increasing concentricity, with a 4-fold increase in the number of fractures in lesions with 360° of calcium arc compared with ≤180°. This increase in IVL-induced calcium fracture with increasing calcium burden and concentricity facilitated stent expansion and luminal gain such that there were no significant differences across quartiles. CONCLUSIONS: IVL induced calcium fractures proportional to the magnitude of coronary artery calcium, including in eccentric calcium, leading to consistent improvements in stent expansion and luminal gain in both eccentric and concentric calcified coronary lesions.

Impact of Post-PCI FFR Stratified by Coronary Artery.

BACKGROUND: Low fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) has been associated with adverse clinical outcomes. Hitherto, this assessment has been independent of the epicardial vessel interrogated. OBJECTIVES: This study sought to assess the predictive capacity of post-PCI FFR for target vessel failure (TVF) stratified by coronary artery. METHODS: We performed a systematic review and individual patient-level data meta-analysis of randomized clinical trials and observational studies with protocol-recommended post-PCI FFR assessment. The difference in post-PCI FFR between left anterior descending (LAD) and non-LAD arteries was assessed using a random-effect models meta-analysis of mean differences. TVF was defined as a composite of cardiac death, target vessel myocardial infarction, and clinically driven target vessel revascularization. RESULTS: Overall, 3,336 vessels (n = 2,760 patients) with post-PCI FFR measurements were included in 9 studies. The weighted mean post-PCI FFR was 0.89 (95% CI: 0.87-0.90) and differed significantly between coronary vessels (LAD = 0.86; 95% CI: 0.85 to 0.88 vs non-LAD = 0.93; 95% CI: 0.91-0.94; P < 0.001). Post-PCI FFR was an independent predictor of TVF, with its risk increasing by 52% for every reduction of 0.10 FFR units, and this was mainly driven by TVR. The predictive capacity for TVF was poor for LAD arteries (AUC: 0.52; 95% CI: 0.47-0.58) and moderate for non-LAD arteries (AUC: 0.66; 95% CI: 0.59-0.73; LAD vs non-LAD arteries, P = 0.005). CONCLUSIONS: The LAD is associated with a lower post-PCI FFR than non-LAD arteries, emphasizing the importance of interpreting post-PCI FFR on a vessel-specific basis. Although a higher post-PCI FFR was associated with improved prognosis, its predictive capacity for events differs between the LAD and non-LAD arteries, being poor in the LAD and moderate in the non-LAD vessels.

Optical Coherence Tomography-Guided versus Angiography-Guided PCI.

BACKGROUND: Data regarding clinical outcomes after optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) as compared with angiography-guided PCI are limited. METHODS: In this prospective, randomized, single-blind trial, we randomly assigned patients with medication-treated diabetes or complex coronary-artery lesions to undergo OCT-guided PCI or angiography-guided PCI. A final blinded OCT procedure was performed in patients in the angiography group. The two primary efficacy end points were the minimum stent area after PCI as assessed with OCT and target-vessel failure at 2 years, defined as a composite of death from cardiac causes, target-vessel myocardial infarction, or ischemia-driven target-vessel revascularization. Safety was also assessed. RESULTS: The trial was conducted at 80 sites in 18 countries. A total of 2487 patients underwent randomization: 1233 patients were assigned to undergo OCT-guided PCI, and 1254 to undergo angiography-guided PCI. The minimum stent area after PCI was 5.72±2.04 mm2 in the OCT group and 5.36±1.87 mm2 in the angiography group (mean difference, 0.36 mm2; 95% confidence interval [CI], 0.21 to 0.51; P<0.001). Target-vessel failure within 2 years occurred in 88 patients in the OCT group and in 99 patients in the angiography group (Kaplan-Meier estimates, 7.4% and 8.2%, respectively; hazard ratio, 0.90; 95% CI, 0.67 to 1.19; P = 0.45). OCT-related adverse events occurred in 1 patient in the OCT group and in 2 patients in the angiography group. Stent thrombosis within 2 years occurred in 6 patients (0.5%) in the OCT group and in 17 patients (1.4%) in the angiography group. CONCLUSIONS: Among patients undergoing PCI, OCT guidance resulted in a larger minimum stent area than angiography guidance, but there was no apparent between-group difference in the percentage of patients with target-vessel failure at 2 years. (Funded by Abbott; ILUMIEN IV: OPTIMAL PCI ClinicalTrials.gov number, NCT03507777.).

Comparison of an Initial Risk-Based Testing Strategy vs Usual Testing in Stable Symptomatic Patients With Suspected Coronary Artery Disease: The PRECISE Randomized Clinical Trial.

Importance: Trials showing equivalent or better outcomes with initial evaluation using coronary computed tomography angiography (cCTA) compared with stress testing in patients with stable chest pain have informed guidelines but raise questions about overtesting and excess catheterization. Objective: To test a modified initial cCTA strategy designed to improve clinical efficiency vs usual testing (UT). Design, Setting, and Participants: This was a pragmatic randomized clinical trial enrolling participants from December 3, 2018, to May 18, 2021, with a median of 11.8 months of follow-up. Patients from 65 North American and European sites with stable symptoms of suspected coronary artery disease (CAD) and no prior testing were randomly assigned 1:1 to precision strategy (PS) or UT. Interventions: PS incorporated the Prospective Multicenter Imaging Study for the Evaluation of Chest Pain (PROMISE) minimal risk score to quantitatively select minimal-risk participants for deferred testing, assigning all others to cCTA with selective CT-derived fractional flow reserve (FFR-CT). UT included site-selected stress testing or catheterization. Site clinicians determined subsequent care. Main Outcomes and Measures: Outcomes were clinical efficiency (invasive catheterization without obstructive CAD) and safety (death or nonfatal myocardial infarction [MI]) combined into a composite primary end point. Secondary end points included safety components of the primary outcome and medication use. Results: A total of 2103 participants (mean [SD] age, 58.4 [11.5] years; 1056 male [50.2%]) were included in the study, and 422 [20.1%] were classified as minimal risk. The primary end point occurred in 44 of 1057 participants (4.2%) in the PS group and in 118 of 1046 participants (11.3%) in the UT group (hazard ratio [HR], 0.35; 95% CI, 0.25-0.50). Clinical efficiency was higher with PS, with lower rates of catheterization without obstructive disease (27 [2.6%]) vs UT participants (107 [10.2%]; HR, 0.24; 95% CI, 0.16-0.36). The safety composite of death/MI was similar (HR, 1.52; 95% CI, 0.73-3.15). Death occurred in 5 individuals (0.5%) in the PS group vs 7 (0.7%) in the UT group (HR, 0.71; 95% CI, 0.23-2.23), and nonfatal MI occurred in 13 individuals (1.2%) in the PS group vs 5 (0.5%) in the UT group (HR, 2.65; 95% CI, 0.96-7.36). Use of lipid-lowering (450 of 900 [50.0%] vs 365 of 873 [41.8%]) and antiplatelet (321 of 900 [35.7%] vs 237 of 873 [27.1%]) medications at 1 year was higher in the PS group compared with the UT group (both P < .001). Conclusions and Relevance: An initial diagnostic approach to stable chest pain starting with quantitative risk stratification and deferred testing for minimal-risk patients and cCTA with selective FFR-CT in all others increased clinical efficiency relative to UT at 1 year. Additional randomized clinical trials are needed to verify these findings, including safety. Trial Registration: ClinicalTrials.gov Identifier: NCT03702244.