A case report of ventricular fibrillation following Shockwave intravascular lithotripsy during percutaneous coronary intervention.

BACKGROUND: Shockwave intravascular lithotripsy (S-IVL) is widely used during percutaneous coronary intervention (PCI) of calcified coronary arteries. Ventricular capture beats during S-IVL are common but arrhythmias are rare. CASE PRESENTATION: A 75-year-old woman was scheduled for PCI to a short, heavily calcified chronic total occlusion of the right coronary artery. After wiring of the occlusion, S-IVL was used to predilated the calcified stenosis. During S-IVL, the patient developed ventricular fibrillation twice. CONCLUSION: To our knowledge, this is only the second reported case of VF during S-IVL. Although very rare, it is important to be aware of this potential and serious complication.

Transient internal mammary artery graft stenosis on early angiography: navigating pitfalls in hybrid myocardial revascularization.

OBJECTIVES: Left internal mammary artery (LIMA) graft stenoses detected at early coronary angiography may be reversible and consequently prompt unnecessary graft revision. We aim to investigate the frequency, natural course, and clinical significance of internal mammary artery graft stenosis upon early angiography in patients undergoing hybrid myocardial revascularization. METHODS: In this retrospective sub-study of the Coronary Hybrid Revascularization Study, we compared graft appearance, ie, stenosis degree and flow, on early (in-hospital) and scheduled follow-up coronary angiography after 1 year. We assessed the change in graft patency using the Fitzgibbon classification (grade A: unimpaired runoff; grade B > 50% stenosis; grade O: occlusion), as well as graft association with adverse events (death, myocardial infarction, stroke, and repeat revascularization) at up to 5-year follow-up. RESULTS: We report clinical follow-up data for all 131 patients included in the Coronary Hybrid Revascularization Study. Change in graft patency was analyzed in 86 patients with satisfactory visualization of the LIMA graft on early and follow-up coronary angiography. All LIMA grafts were patent at discharge and follow-up. Twenty-seven of 37 (73%) grade B graft stenoses at early angiography resolved to grade A during follow-up of median 12 months (range, 8-83 months) after surgery. Angiographically significant graft stenoses at early coronary angiography were not associated with adverse clinical outcome up to 5-year follow-up. CONCLUSIONS: Our results suggest that the majority of clinically silent LIMA graft stenoses resolve during follow-up and are not associated with adverse clinical outcomes.

Optimal diagnostic approach for using CT-derived quantitative flow ratio in patients with stenosis on coronary computed tomography angiography.

BACKGROUND: Coronary computed tomography angiography (CCTA)-derived quantitative flow ratio (CT-QFR) is an on-site non-invasive technique estimating invasive fractional flow reserve (FFR). This study assesses the diagnostic performance of using most distal CT-QFR versus lesion-specific CT-QFR approach for identifying hemodynamically obstructive coronary artery disease (CAD). METHODS: Prospectively enrolled de novo chest pain patients (n â€‹= â€‹445) with ≥50 â€‹% visual diameter stenosis on CCTA were referred for invasive evaluation. On-site CT-QFR was analyzed post-hoc blinded to angiographic data and obtained as both most distal (MD-QFR) and lesion-specific CT-QFR (LS-QFR). Abnormal CT-QFR was defined as ≤0.80. Hemodynamically obstructive CAD was defined as invasive FFR ≤0.80 or ≥70 â€‹% diameter stenosis by 3D-quantitative coronary angiography. RESULTS: In total 404/445 patients had paired CT-QFR and invasive analyses of whom 149/404 (37 â€‹%) had hemodynamically obstructive CAD. MD-QFR and LS-QFR classified 188 (47 â€‹%) and 165 (41 â€‹%) patients as abnormal, respectively. Areas under the receiver-operating characteristic curve for MD-QFR was 0.83 vs. 0.85 for LS-QFR, p â€‹= â€‹0.01. Sensitivities for MD-QFR and LS-QFR were 80 â€‹% (95%CI: 73-86) vs. 77 â€‹% (95%CI: 69-83), p â€‹= â€‹0.03, respectively, and specificities were 73 â€‹% (95%CI: 67-78) vs. 80 â€‹% (95%CI: 75-85), p â€‹< â€‹0.01, respectively. Positive predictive values for MD-QFR and LS-QFR were 63 â€‹% vs. 69 â€‹%, p â€‹< â€‹0.01, respectively, and negative predictive values for MD-QFR and LS-QFR were 86 â€‹% vs. 85 â€‹%, p â€‹= â€‹0.39, respectively). CONCLUSION: Using a lesion-specific CT-QFR approach has superior discrimination of hemodynamically obstructive CAD compared to a most distal CT-QFR approach. CT-QFR identified most cases of hemodynamically obstructive CAD while a normal CT-QFR excluded hemodynamically obstructive CAD in the majority of patients.

Long-term outcomes after coronary intervention with biodegradable polymer stents in patients with acute coronary syndromes.

BACKGROUND: Patients with acute coronary syndromes (ACS) may have worse outcomes after percutaneous coronary intervention compared to patients without ACS. AIMS: To compare 5-year efficacy and safety outcomes in patients with and without ACS treated with biodegradable polymers, the ultrathin strut sirolimus-eluting Orsiro stent (O-SES) or the biolimus-eluting Nobori stent (N-BES). METHODS: The Scandinavian Organisation for Randomized Trials with Clinical Outcome VII is a randomized trial comparing O-SES and N-BES in an all-comer setting. Of 2525 patients, 1329 (53%) patients had ACS and 1196 (47%) patients were without ACS. Endpoints were target lesion failure (TLF) (a composite of cardiac death, target lesion myocardial infarction, or target lesion revascularization) and definite stent thrombosis within 5 years. RESULTS: At 5-year follow-up, TLF did not differ significantly between patients with and without ACS (12.3% vs. 13.2%; rate ratio (RR) 1.00; 95% confidence interval (CI): 0.70-1.44), whereas the risk of definite stent thrombosis was increased in patients with ACS (2.3% vs. 1.3; RR: 2.01 [95% CI: 1.01-3.98]). In patients with ACS, the rate of TLF was similar between O-SES and N-BES (12.4% vs. 12.3%; RR: 1.02; 95% CI: 0.74-1.40). The reduced risk of definite stent thrombosis in O-SES treated ACS patients within the first year (0.2% vs. 1.6%; RR: 0.12; 95% CI: 0.02-0.93) was not maintained after 5 years (1.8% vs. 2.7%; RR: 0.77; 95% CI: 0.37-1.63). CONCLUSION: Patients with ACS had an increased risk of stent thrombosis regardless of the stent type used. Long-term outcomes were similar for ACS patients treated with O-SES or N-BES at 5 years.

Chronic Total Occlusion is Not a Risk Factor for Mortality in Patients With Successful Percutaneous Coronary Intervention: A Cohort Study.

Background Fifteen percent of patients with coronary artery disease undergoing angiography have a chronic total occlusion (CTO). The current study aimed to investigate the long-term prognosis after successful and unsuccessful CTO percutaneous coronary intervention (PCI) compared with PCI for non-CTO lesions. Methods and Results The current study was designed as an observational, region-wide, register-based cohort study enrolling all patients undergoing PCI in the Central Region of Denmark in 2009 to 2019. Patients were stratified into non-CTO, successful CTO, and unsuccessful CTO revascularization. Patients were followed until an event or January 1, 2022. The primary end point was all-cause mortality. In 21 141 patients enrolled, 2108 underwent CTO PCI. Clinical presentation was acute coronary syndrome in 11 879 patients and chronic coronary syndrome in 7887 patients. After a median of 5.7 years (interquartile range, 3.3-8.8), long-term all-cause mortality was higher after CTO PCI compared with non-CTO PCI, but the difference was statistically insignificant when adjusting for clinical factors (unadjusted hazard ratio [HR], 1.19 [95% CI, 1.09-1.29], adjusted HR, 1.08 [95% CI, 0.97-1.20]; P=0.165). After successful CTO PCI, no difference compared with non-CTO PCI was observed (unadjusted HR, 0.99 [95% CI, 0.90-1.10], adjusted HR, 0.99 [95% CI, 0.87-1.12]; P=0.873). After unsuccessful CTO PCI, long-term all-cause mortality was higher than non-CTO PCI (unadjusted HR, 1.82 [95% CI, 1.59-2.08], adjusted HR, 1.35 [95% CI, 1.13-1.63]; P<0.001). Conclusions Patients undergoing PCI for CTO have elevated long-term mortality compared with patients without CTO. Successful opening of the CTO(s) is associated with equal mortality compared with non-CTO PCI. In contrast, failed CTO PCI is associated with worse long-term mortality. These findings suggest the need for CTO programs with high success rates and low complication rates.

Sex differences in prevalence and outcomes of the different endotypes of chronic coronary syndrome in symptomatic patients undergoing invasive coronary angiography: Insights from the global ILIAS invasive coronary physiology registry.

BACKGROUND AND AIMS: The management of chronic coronary syndrome (CCS) is informed by studies predominantly including men. This study investigated the relationship between patients sex and different endotypes of CCS, including sex-specific clinical outcomes. METHODS: In patients with CCS undergoing coronary angiography, invasive Fractional Flow Reserve (FFR) and Coronary Flow Reserve (CFR) were measured. Patients were stratified into groups: 1) obstructive coronary artery disease (oCAD) (FFR≤0.80, no revascularization), 2) undergoing revascularization, 3) non-obstructive coronary artery disease with coronary microvascular dysfunction (CMD) (FFR>0.80, CFR≤2.5), and 4) non-obstructive coronary artery disease without CMD (FFR>0.80 and CFR>2.5). RESULTS: 1836 patients (2335 vessels) were included, comprising 1359 (74.0%) men and 477 (26.0%) women. oCAD was present in 14.1% and was significantly less prevalent in women than in men (10.3% vs 15.5%, respectively p < 0.01). Revascularization was present in 30.9% and was similarly prevalent in women and men (28.2% vs. 31.9%, respectively p = 0.13). CMD was present in 24.2% and was significantly more prevalent in women than men (28.6% vs 22.6%, respectively p < 0.01). Normal invasive measurements were found in 564 patients (33.0% women vs 30.0% men, p = 0.23). Male sex was associated with an increased risk of target vessel failure compared to women (HR.1.89, 95% CI 1.12-3.18, p = 0.018), regardless of CCS-endotype. CONCLUSIONS: Sex differences exist in the prevalence and outcomes of different endotypes of CCS in symptomatic patients undergoing invasive coronary angiography. In particular, oCAD (and subsequent revascularization) were more prevalent in men. Conversely, CMD was more prevalent in women. Overall, men experienced a worse cardiovascular outcome compared to women, independent of any specific CCS endotype.

Rationale and design of the pullback pressure gradient (PPG) global registry.

INTRODUCTION: Diffuse disease has been identified as one of the main reasons leading to low post-PCI fractional flow reserve (FFR) and residual angina after PCI. Coronary pressure pullbacks allow for the evaluation of hemodynamic coronary artery disease (CAD) patterns. The pullback pressure gradient (PPG) is a novel metric that quantifies the distribution and magnitude of pressure losses along the coronary artery in a focal-to-diffuse continuum. AIM: The primary objective is to determine the predictive capacity of the PPG for post-PCI FFR. METHODS: This prospective, large-scale, controlled, investigator-initiated, multicenter study is enrolling patients with at least 1 lesion in a major epicardial vessel with a distal FFR ≤ 0.80 intended to be treated by PCI. The study will include 982 subjects. A standardized physiological assessment will be performed pre-PCI, including the online calculation of PPG from FFR pullbacks performed manually. PPG quantifies the CAD pattern by combining several parameters from the FFR pullback curve. Post-PCI physiology will be recorded using a standardized protocol with FFR pullbacks. We hypothesize that PPG will predict optimal PCI results (post-PCI FFR ≥ 0.88) with an area under the ROC curve (AUC) ≥ 0.80. Secondary objectives include patient-reported and clinical outcomes in patients with focal vs. diffuse CAD defined by the PPG. Clinical follow-up will be collected for up to 36 months, and an independent clinical event committee will adjudicate events. RESULTS: Recruitment is ongoing and is expected to be completed in the second half of 2023. CONCLUSION: This international, large-scale, prospective study with pre-specified powered hypotheses will determine the ability of the preprocedural PPG index to predict optimal revascularization assessed by post-PCI FFR. In addition, it will evaluate the impact of PPG on treatment decisions and the predictive performance of PPG for angina relief and clinical outcomes.

Instantaneous wave free ratio vs. fractional flow reserve and 5-year mortality: iFR SWEDEHEART and DEFINE FLAIR.

BACKGROUND AND AIMS: Guidelines recommend revascularization of intermediate epicardial artery stenosis to be guided by evidence of ischaemia. Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are equally recommended. Individual 5-year results of two major randomized trials comparing FFR with iFR-guided revascularization suggested increased all-cause mortality following iFR-guided revascularization. The aim of this study was a study-level meta-analysis of the 5-year outcome data in iFR-SWEDEHEART (NCT02166736) and DEFINE-FLAIR (NCT02053038). METHODS: Composite of major adverse cardiovascular events (MACE) and its individual components [all-cause death, myocardial infarction (MI), and unplanned revascularisation] were analysed. Raw Kaplan-Meier estimates, numbers at risk, and number of events were extracted at 5-year follow-up and analysed using the ipdfc package (Stata version 18, StataCorp, College Station, TX, USA). RESULTS: In total, iFR and FFR-guided revascularization was performed in 2254 and 2257 patients, respectively. Revascularization was more often deferred in the iFR group [n = 1128 (50.0%)] vs. the FFR group [n = 1021 (45.2%); P = .001]. In the iFR-guided group, the number of deaths, MACE, unplanned revascularization, and MI was 188 (8.3%), 484 (21.5%), 235 (10.4%), and 123 (5.5%) vs. 143 (6.3%), 420 (18.6%), 241 (10.7%), and 123 (5.4%) in the FFR group. Hazard ratio [95% confidence interval (CI)] estimates for MACE were 1.18 [1.04; 1.34], all-cause mortality 1.34 [1.08; 1.67], unplanned revascularization 0.99 [0.83; 1.19], and MI 1.02 [0.80; 1.32]. CONCLUSIONS: Five-year all-cause mortality and MACE rates were increased with revascularization guided by iFR compared to FFR. Rates of unplanned revascularization and MI were equal in the two groups.

Changes in microvascular resistance following percutaneous coronary intervention - From the ILIAS global registry.

BACKGROUND: Microvascular resistance (MR) has prognostic value in acute and chronic coronary syndromes following percutaneous coronary intervention (PCI), however anatomic and physiologic determinants of the relative changes of MR and its association to target vessel failure (TVF) has not been investigated previously. This study aims to evaluate the association between changes in MR and TVF. METHODS: This is a sub-study of the Inclusive Invasive Physiological Assessment in Angina Syndromes (ILIAS) registry which is a global multi-centre initiative pooling lesion-level coronary pressure and flow data. RESULTS: Paired pre-post PCI haemodynamic data were available in n = 295 vessels out of n = 828 PCI treated patients and of these paired data on MR was present in n = 155 vessels. Vessels were divided according to increase vs. decrease % in microvascular resistance following PCI (ΔMR % ≤ 0 vs. ΔMR > 0%). Decreased microvascular resistance ΔMR % ≤ 0 occurred in vessels with lower pre-PCI fractional flow reserve (0.67 ± 0.15 vs. 0.72 ± 0.09 p = 0.051), coronary flow reserve (1.9 ± 0.8 vs. 2.6 ± 1.8 p < 0.0001) and higher hyperemic microvascular resistance (2.76 ± 1.3 vs. 1.62 ± 0.74 p = 0.001) and index of microvascular resistance (24.4 IQ (13.8) vs. 15. 8 IQ (13.2) p = 0.004). There was no difference in angiographic parameters between ΔMR % ≤ 0 vs. ΔMR > 0%. In a cox regression model ΔMR % > 0 was associated with increased rate of TVF (hazard ratio 95% CI 3.6 [1.2; 10.3] p = 0.018). CONCLUSION: Increased MR post-PCI was associated with lesions of less severe hemodynamic influence at baseline and higher rates of TVF at follow-up.

Three-year outcomes of A Randomized Multicentre Trial Comparing Revascularization and Optimal Medical Therapy for Chronic Total Coronary Occlusions (EuroCTO).

BACKGROUND: Percutaneous coronary intervention (PCI) for chronic total coronary occlusions (CTO) improves clinical symptoms and quality of life. The longer-term safety of PCI compared to optimal medical therapy (OMT) remains uncertain. AIMS: We sought to evaluate the long-term safety of PCI for CTO in a randomised trial as compared to OMT. METHODS: A total of 396 patients with a symptomatic CTO were enrolled into a randomised, multicentre clinical trial comparing PCI and OMT. Half of the patients had a single CTO; the others had multivessel disease. Non-CTO lesions were treated prior to randomisation (2:1 ratio). During follow-up, crossover from OMT to PCI occurred in 7.3% (1 year) and 17.5% (3 years) of patients. RESULTS: At 3 years, the incidence of cardiovascular death or nonfatal myocardial infarction was not significantly different between the groups (OMT 3.7% vs PCI 6.2%; p=0.29). By per-protocol analysis, the difference remained non-significant (OMT 5.7% vs PCI 4.7%; p=0.67). Overall, major adverse cardiovascular events (MACE) were more frequent with OMT (OMT 21.2% vs PCI 11.2%), largely because of ischaemia-driven revascularisation. The rates of stroke or hospitalisation for bleeding were not different between the groups. CONCLUSIONS: At 3 years there was no difference in the rate of cardiovascular death or myocardial infarction between PCI or OMT among patients with a remaining single coronary CTO. The MACE rate was higher in the OMT group due largely to ischaemia-driven revascularisation. CTO PCI appears to be a safe option for patients with a single remaining significant coronary CTO. CinicalTrials.gov: NCT01760083.

Comparison of definitions of coronary artery reference sizes and effects on stent selection and evaluation of stent expansion.

Accurate determination of coronary reference size is essential for optimal stent selection and evaluation of stent expansion during percutaneous coronary intervention (PCI). Several approaches for reference size estimation have been published with no universal agreement. The aim of this study was to investigate if potential differences in coronary reference size estimation lead to differences in stent and balloon selection and in detection of stent under expansion. Definitions for coronary reference size estimation, stent size selection, and stent expansion were identified in 17 randomized controlled trials. The identified methods were applied in a population of 32 clinical cases. Reference size estimates ranged up to 1.35mm, and indicated nominal stent size ranged up to 1.0 mm in the same case depending on method. Mean relative stent expansion ranged from 54±12% to mean 100±29% depending on the applied reference method. Choice of method for reference size estimation using intravascular imaging may influence stent selection and greatly affects evaluation of post-PCI stent expansion.

Danish study of Non-Invasive Testing in Coronary Artery Disease 3 (Dan-NICAD 3): study design of a controlled study on optimal diagnostic strategy.

INTRODUCTION: Current guideline recommend functional imaging for myocardial ischaemia if coronary CT angiography (CTA) has shown coronary artery disease (CAD) of uncertain functional significance. However, diagnostic accuracy of selective myocardial perfusion imaging after coronary CTA is currently unclear. The Danish study of Non-Invasive testing in Coronary Artery Disease 3 trial is designed to evaluate head to head the diagnostic accuracy of myocardial perfusion imaging with positron emission tomography (PET) using the tracers 82Rubidium (82Rb-PET) compared with oxygen-15 labelled water PET (15O-water-PET) in patients with symptoms of obstructive CAD and a coronary CT scan with suspected obstructive CAD. METHODS AND ANALYSIS: This prospective, multicentre, cross-sectional study will include approximately 1000 symptomatic patients without previous CAD. Patients are included after referral to coronary CTA. All patients undergo a structured interview and blood is sampled for genetic and proteomic analysis and a coronary CTA. Patients with possible obstructive CAD at coronary CTA are examined with both 82Rb-PET, 15O-water-PET and invasive coronary angiography with three-vessel fractional flow reserve and thermodilution measurements of coronary flow reserve. After enrolment, patients are followed with Seattle Angina Questionnaires and follow-up PET scans in patients with an initially abnormal PET scan and for cardiovascular events in 10 years. ETHICS AND DISSEMINATION: Ethical approval was obtained from Danish regional committee on health research ethics. Written informed consent will be provided by all study participants. Results of this study will be disseminated via articles in international peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT04707859.

Real-World Experience with Cangrelor as Adjuvant to Percutaneous Coronary Intervention: A Single-Centre Observational Study.

Background: Reversible P2Y12 inhibition can be obtained with cangrelor administered intravenously. More experience with cangrelor use in acute PCI with unknown bleeding risk is needed. Objectives: To describe real-world use of cangrelor including patient and procedure characteristics and patient outcomes. Methods: We performed a single-centre, retrospective, and observational study including all patients treated with cangrelor in relation to percutaneous coronary intervention at Aarhus University Hospital during the years 2016, 2017, and 2018. We recorded procedure indication and priority, the indications for cangrelor use, and patient outcomes within the first 48 hours after initiation of cangrelor treatment. Results: We treated 991 patients with cangrelor in the study period. Of these, 869 (87.7%) had an acute procedure priority. Among acute procedures, patients were mainly treated for STEMI (n = 723) and the remaining were treated for cardiac arrest and acute heart failure. Use of oral P2Y12 inhibitors prior to percutaneous coronary intervention was rare. Fatal bleeding events (n = 6) were only observed among patients undergoing acute procedures. Stent thrombosis was observed in two patients receiving acute treatment for STEMI. Thus, cangrelor can be used in relation to PCI under acute circumstances with advantages in terms of clinical management. The benefits and risks, in terms of patient outcomes, should ideally be assessed in randomized trials.

Myocardial perfusion imaging by 15O-H2O positron emission tomography predicts clinical revascularization procedures in symptomatic patients with previous coronary artery bypass graft.

Aims: We wanted to assess if 15O-H2O myocardial perfusion imaging (MPI) in a clinical setting can predict referral to coronary artery catheterization [coronary angiography (CAG)], execution of percutaneous coronary intervention (PCI), and post-PCI angina relief for patients with angina and previous coronary artery bypass graft (CABG). Methods and results: We analysed 172 symptomatic CABG patients referred for 15O-H2O positron emission tomography (PET) MPI at Aarhus University Hospital Department of Nuclear Medicine & PET Centre, of which five did not complete the scan. In total, 145 (87%) enrolled patients had an abnormal MPI. Of these, 86/145 (59%) underwent CAG within 3 months; however, no PET parameters predicted referral to CAG. During the CAG, 25/86 (29%) patients were revascularized by PCI. Relative flow reserve (RFR) (0.49 vs. 0.54 P = 0.03), vessel-specific myocardial blood flow (MBF) (1.53 vs. 1.88 mL/g/min, P < 0.01), and vessel-specific myocardial flow reserve (MFR) (1.73 vs. 2.13, P < 0.01) were significantly lower in patients revascularized by PCI. Receiver operating characteristic analysis of the vessel-specific parameters yielded optimal cutoffs of 1.36 mL/g/min (MBF) and 1.28 (MFR) to predict PCI. Angina relief was experienced by 18/24 (75%) of the patients who underwent PCI. Myocardial blood flow was an excellent predictor of angina relief on both a global [area under the curve (AUC) = 0.85, P < 0.01] and vessel-specific (AUC = 0.90, P < 0.01) level with optimal cutoff levels of 1.99 mL/g/min and 1.85 mL/g/min, respectively. Conclusion: For CABG patients, RFR, vessel-specific MBF, and vessel-specific MFR measured by 15O-H2O PET MPI predict whether subsequent CAG will result in PCI. Additionally, global and vessel-specific MBF values predict post-PCI angina relief.

Coronary Artery Stenosis Evaluation by Angiography-Derived FFR: Validation by Positron Emission Tomography and Invasive Thermodilution.

BACKGROUND: Fractional flow reserve (FFR) derived from invasive coronary angiography (QFR) is promising for evaluation of intermediate coronary artery stenosis. OBJECTIVES: The authors aimed to compare the diagnostic performance of QFR and the guideline-recommended invasive FFR using 82Rubidium positron emission tomography (82Rb-PET) myocardial perfusion imaging as reference standard. METHODS: This is a prospective, observational study of symptomatic patients with suspected obstructive coronary artery disease on coronary computed tomography angiography (≥50% diameter stenosis in ≥1 vessel). All patients were referred to 82Rb-PET and invasive coronary angiography with FFR and QFR assessment of all intermediate (30%-90% diameter stenosis) stenoses. Main analyses included a comparison of the ability of QFR and FFR to identify reduced myocardial blood flow (<2 mL/g/min) during vasodilation and/or relative perfusion abnormalities (summed stress score ≥4 in ≥2 adjacent segments). RESULTS: A total of 250 patients (320 vessels) with indication for invasive physiological assessment were included. The continuous relationship of 82Rb-PET stress myocardial blood flow per 0.10 increase in FFR was +0.14 mL/g/min (95% CI: 0.07-0.21 mL/g/min) and +0.08 mL/g/min (95% CI: 0.02-0.14 mL/g/min) per 0.10 QFR increase. Using 82Rb-PET as reference, QFR and FFR had similar diagnostic performance on both a per-patient level (accuracy: 73%; 95% CI: 67%-79%; vs accuracy: 71%; 95% CI: 64%-78%) and per-vessel level (accuracy: 70%; 95% CI: 64%-75%; vs accuracy: 68%; 95% CI: 62%-73%). The per-vessel feasibility was 84% (95% CI: 80%-88%) for QFR and 88% (95% CI: 85%-92%) for FFR by intention-to-diagnose analysis. CONCLUSIONS: With 82Rb-PET as reference modality, the wire-free QFR solution showed similar diagnostic accuracy as invasive FFR in evaluation of intermediate coronary stenosis. (DAN-NICAD - Danish Study of Non-Invasive Diagnostic Testing in Coronary Artery Disease; NCT02264717).

Second-Line Myocardial Perfusion Imaging to Detect Obstructive Stenosis: Head-to-Head Comparison of CMR and PET.

BACKGROUND: Guidelines recommend verification of myocardial ischemia by selective second-line myocardial perfusion imaging (MPI) following a coronary computed tomography angiography (CTA) with suspected obstructive coronary artery disease (CAD). Head-to-head data on the diagnostic performance of different MPI modalities in this setting are sparse. OBJECTIVES: The authors sought to compare, head-to-head, the diagnostic performance of selective MPI by 3.0-T cardiac magnetic resonance (CMR) and 82rubidium positron emission tomography (RbPET) in patients with suspected obstructive stenosis at coronary CTA using invasive coronary angiography (ICA) with fractional flow reserve (FFR) as reference. METHODS: Consecutive patients (n = 1,732, mean age: 59.1 ± 9.5 years, 57.2% men) referred for coronary CTA with symptoms suggestive of obstructive CAD were included. Patients with suspected stenosis were referred for both CMR and RbPET and subsequently ICA. Obstructive CAD was defined as FFR ≤0.80 or >90% diameter stenosis by visual assessment. RESULTS: In total, 445 patients had suspected stenosis on coronary CTA. Of these, 372 patients completed both CMR, RbPET and subsequent ICA with FFR. Hemodynamically obstructive CAD was identified in 164 of 372 (44.1%) patients. Sensitivities for CMR and RbPET were 59% (95% CI: 51%-67%) and 64% (95% CI: 56%-71%); P = 0.21, respectively, and specificities 84% (95% CI: 78%-89%) and 89% (95% CI: 84%-93%]); P = 0.08, respectively. Overall accuracy was higher for RbPET compared with CMR (73% vs 78%; P = 0.03). CONCLUSIONS: In patients with suspected obstructive stenosis at coronary CTA, CMR, and RbPET show similar and moderate sensitivities but high specificities compared with ICA with FFR. This patient group represents a diagnostic challenge with frequent mismatch between advanced MPI tests and invasive measurements. (Danish Study of Non-Invasive Diagnostic Testing in Coronary Artery Disease 2 [Dan-NICAD 2]; NCT03481712).