Anatomic and functional discordance among patients with non-obstructive coronary disease

Background

Non-obstructive coronary artery disease (CAD) is associated with increased adverse cardiovascular (CV) events. However, it is unclear if functional stenosis, as assessed by FFRCT <0.80, further stratifies risk among patients with non-obstructive CAD and which factors contribute to this anatomic-functional discordance (stenosis <50% and FFRCT <0.80).

Purpose

We hypothesized that patients with anatomically non-obstructive CAD by CTA and an abnormal FFRCT value of ≤0.80 have a phenomenon termed anatomic-functional discordance, and this discordance would be associated with increased adverse outcomes.

Methods

Patients in the ADVANCE (Assessing Diagnostic Value of Non-invasive FFRCT in Coronary Care) Registry who had exclusively non-obstructive CAD (anatomic stenosis <50%) were stratified by FFRCT >0.80 in all coronary vessels (concordant) vs. FFRCT <0.80 in at least one vessel (discordant). Baseline patient demographics, coronary computed tomography angiography findings, downstream testing and clinical outcomes were compared between groups. The primary composite endpoint included revascularization, CV hospitalization, heart failure, arrhythmia, non-fatal myocardial infarction, unplanned hospitalization for an acute coronary syndrome leading to urgent revascularization, and all-cause death.

Results

Among 1,261 patients with non-obstructive CAD, 543 (43.1%) had functional stenosis with FFRCT <0.80. Patients in the discordant group were older, more likely to have hypertension, hyperlipidemia, and had significantly higher indexed left ventricular (LV) mass and significantly lower coronary volume-to-mass ratios when compared with patients in the concordant group. Downstream non-invasive testing was more common among patients with discordance (35.9% vs 20.2%, p<0.0001) and more frequently resulted in a positive downstream test (10.3% vs. 3.3%, p<0.0001). Invasive angiography was also more common among patients with discordance (25.2% vs. 11.6%, p<0.0001). Anatomic-functional discordance was associated with higher rates of CV hospitalization and percutaneous coronary intervention (both p<0.0001), but no significant difference in all-cause death. After adjustment, anatomic-functional discordance was associated with a significantly higher risk of the composite endpoint (adjusted HR 2.79, 95% CI 1.67–4.65), Figure 1. As shown in Figure 2, the more vessels with anatomic-functional discordance, the higher the rate of adverse cardiac events.

Conclusion

Anatomic-functional discordance was present in nearly half of patients with exclusively non-obstructive CAD. The lower coronary volume: LV mass ratio may reflect abnormal coronary physiology at lower thresholds of anatomical stenosis among those with discordance. Compared to patients with concordance, patients with discordance had worse clinical outcomes suggesting that anatomic-functional discordance may stratify risk for adverse CV events among patients with non-obstructive CAD.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): The analysis was an investigator-initiated analysis sponsored by Heart Flow.

Prognostic value of FFRCT in patients with stable chest pain – a 3-year follow-up of the ADVANCE-DK registry

Introduction

The short-term safety of using coronary CT angiography (CTA) derived fractional flow reserve (FFRCT) to guide downstream testing after CTA is well documented. Whether the prognostic information provided by FFRCT can be extended to sustained follow-up and to patients with a high degree of coronary artery calcification (CAC) is unknown.

Purpose

To evaluate the association between FFRCT and clinical outcomes in new onset stable symptomatic patients with coronary stenosis up to 3 years after CTA index testing.

Methods

Multicenter 3-year follow-up study of 900 patients from the Assessing Diagnostic Value of Non-invasive FFRCT in Coronary Care (ADVANCE) registry at three Danish sites, the “ADVANCE-DK Registry”. All patients had at least one ≥30% coronary stenosis by CTA and underwent subsequent core laboratory FFRCT analysis by HeartFlow. The criterium for an abnormal FFRCT test result was an FFRCT value ≤0.80 (2 cm distal to stenosis). High CAC was defined as a CAC score ≥400. The primary endpoint (PE) was a composite of all-cause death and spontaneous myocardial infarction (MI). The secondary endpoint (SE) was a composite of cardiovascular (CV) death and spontaneous MI. Events were adjudicated by an independent clinical committee.

Results

Patient characteristics are given in Table 1. Coronary stenosis ≥50% was present in 750 (83%) patients. In total 36 patients suffered a PE (all-cause death, n=24; MI, n=12) and 22 an SE (CV death, n=10; MI, n=12). An abnormal vs a normal FFRCT test result was associated with an increased risk of the PE and of the SE both overall and in patients with high CAC; PE (all), 6.6% vs 2.1%, relative risk (RR): 3.1; 95% CI: 1.6–6.3, p<0.001, SE (all), 5.0% vs 0.6%, RR: 8.7; 95% CI: non assessable, p<0.001, PE (high CAC), 9.0% vs 2.2%, RR: 4.1; 85% CI: 1.4–11.8, p=0.001, and SE (high CAC), 6.6% vs 0.5%, RR: 12.0; 95% CI: non assessable, p=0.01, respectively, Figure 1. The observed increased risk in patients with an abnormal vs a normal FFRCT test result persisted after adjustment for degree of stenosis by CCTA (< / ≥50%) and amount of CAC (< / ≥400): PE, adjusted RR: 2.5; 95% CI: 1.2–5.2, p=0.02, and SE, adjusted RR: 8.0; 95% CI: 2.1–30.2, p=0.002.

Conclusion

Patients with stable chest pain, stenosis by CTA and a normal FFRCT test result have a low risk of adverse outcomes during 3 years of follow-up. An abnormal FFRCT identifies patients at increased risk of death or spontaneous MI. These associations are consistent in patients with high levels of CAC.

Funding Acknowledgement

Type of funding sources: None.

FFRCT and recurrent symptoms in patients with stable chest pain

Introduction

The major benefit of coronary revascularization when compared with optimal medical treatment (OMT) in patients with stable chest pain (CP) relates to improvement of symptoms and reduction of reinterventions. Non-invasive methods are warranted to discriminate between patients at low and high risk of recurrent CP for subsequent guidance of antianginal treatment (invasive or OMT).

Purpose

To evaluate the association between coronary CT angiography (CTA) derived fractional flow reserve (FFRCT), recurrent CP and quality of life (QOL) in patients with new onset stable CP and stenosis by CTA.

Methods

Multicenter cohort 3-year follow-up sub-study of 769 patients from the Assessing Diagnostic Value of Non-invasive FFRCT in Coronary Care (ADVANCE) registry at three Danish sites, the “ADVANCE-DK Registry”. All patients had at least one ≥30% coronary stenosis by CTA and underwent subsequent core laboratory FFRCT analysis by HeartFlow. An abnormal FFRCT was defined as the lowest in vessel FFRCT value ≤0.80. Patients were classified according to completeness of revascularization by FFRCT: 1) completely revascularized (CR-FFRCT), all coronary arteries with an abnormal FFRCT test result revascularized; 2) incompletely revascularized (IR-FFRCT), ≥1 coronary artery with an abnormal FFRCT test result not revascularized. All patients completed the Seattle Angina Questionnaire (SAQ-7), the EuroQol questionnaire (EQ-5D-5L) and graded (0–100) overall health using the EQ VAS scale at 3-year follow-up. Recurrent CP was defined as CP within the last 4 weeks prior to this follow-up.

Results

Patient characteristics are given in Table 1. At follow-up 23% patients reported recurrent CP. An abnormal vs a normal FFRCT increased the risk of recurrent CP, 27% vs 15%, RR: 1.82; 95% CI: 1.31–2.52, p<0.001. Amongst patients with abnormal FFRCT, revascularization (+/−) was associated to a numerical, but not statistical significantly, reduced risk of recurrent CP, 23% vs 30%, RR: 0.76; 95% CI: 0.56–1.03, p=0.07. IR-FFRCT vs CR-FFRCT had a higher risk for recurrent CP, 31% vs 13%, RR: 2.34; 95% CI: 1.48–3.68, p<0.001, whilst no difference was observed for CR-FFRCT vs normal FFRCT, 13% vs 15%, RR: 0.92; 95% CI: 0.54–1.54, p=0.74. IR-FFRCT vs CR-FFRCT or normal FFRCT, had lower SAQ-7, EQ-5D-5L and EQ-VAS scores, Table 1, all p<0.005. Scores for three selected SAQ-7 domains are shown in Figure 1. Use of antianginal medicine was higher in IR-FFRCT compared to CR-FFRCT and normal FFRCT, mean ± SD: 1.2±0.05 vs 1.0±0.04, p=0.02.

Conclusion

An abnormal FFRCT identifies patients with an increased risk of recurrent CP up to 3 years after index testing. Completeness of revascularization by FFRCT reclassifies patients with abnormal FFRCT into groups with low and high risk for recurrent CP and impaired QOL.

Funding Acknowledgement

Type of funding sources: None.

Completeness of revascularization by FFRCT and prognosis in stable chest pain

Introduction

Major randomized trials of patients with stable chest pain (CP) demonstrated no prognostic benefits of coronary revascularization over optimal medical treatment (OMT). However, in a recent large-scale study, completeness of revascularization was associated with a reduced risk of all-cause death and non-fatal myocardial infarction (MI).

Purpose

To evaluate the association between completeness of revascularization relative to the result of coronary CT angiography (CTA) derived fractional flow reserve (FFRCT) and 3-year prognosis in patients with new onset stable CP and coronary stenosis.

Methods

Multicenter cohort 3-year follow-up sub-study of 900 patients from the Assessing Diagnostic Value of Non-invasive FFRCT in Coronary Care (ADVANCE) registry at three Danish sites, the “ADVANCE-DK Registry”. All patients had at least one ≥30% coronary stenosis by CTA and underwent subsequent core laboratory FFRCT analysis by HeartFlow. The FFRCT result was abnormal when ≤0.80 (2 cm distal to stenosis). Patients were classified according to completeness of revascularization by FFRCT: 1) completely revascularized (CR-FFRCT), all coronary arteries with an abnormal FFRCT test result revascularized; 2) incompletely revascularized (IR-FFRCT), ≥1 coronary artery with an abnormal FFRCT test result not revascularized. The primary endpoint (PE) was a composite of all-cause death and spontaneous MI. The secondary endpoint (SE) was a composite of cardiovascular (CV) death and spontaneous MI.

Results

Patient characteristics are given in Table 1. In total 36 (4.0%) patients suffered a PE (all-cause death, n=24; MI, n=12) and 22 (2.4%) an SE (CV death, n=10; MI, n=12). Overall, an abnormal vs a normal FFRCT test result was associated with an increased risk of both the PE, 6.6% vs 2.1%, relative risk (RR): 3.1; 95% CI: 1.6–6.3, p<0.001 and of the SE, 5.0% vs 0.6%, RR: 8.7; 95% CI: non assessable, p<0.001. In patients with abnormal FFRCT, revascularization vs no revascularization did not reduce the risk of the PE or the SE (data not shown). Patients with IR-FFRCT vs CR-FFRCT had a numerical, but not statistical significantly, increased risk of the PE, 8.6% vs 4.2%, RR: 2.14; 95% CI: 0.87–5.26, p=0.10), and an increased risk of the SE, 7.1% vs 2.4%, RR: 3.13; 95% CI: 1.02–9.63, p=0.04, Figure 1. In CR-FFRCT versus normal FFRCT no difference in the risk of the PE or the SE was observed, Figure 1. Univariate sensitivity analyses performed in the IR-FFRCT group did not reveal any differences in the risk of the PE or the SE after adjustment for neither statin therapy at follow-up (−/+), baseline risk variables (< / ≥3), amount of CAC (< / ≥400), degree of stenosis by CTA (< / ≥50%) nor referral to ICA (−/+).

Conclusion

In symptomatic patients with coronary stenosis by CTA, incomplete revascularization determined by FFRCT is associated with an increased risk of adverse cardiovascular outcomes compared to complete revascularization.

Funding Acknowledgement

Type of funding sources: None.

Trans-stenotic pressure gradient as derived from CT improves patient management: ADVANCE registry

Background

The change in fractional flow reserve derived from CT (FFRCT) value across a coronary stenosis (ΔFFRCT) improves the physiological characterization of coronary artery disease (CAD). The role of ΔFFRCT in guiding risk-stratification and downstream testing in patients with stable CAD is unknown.

Purpose

To investigate the incremental value of ΔFFRCT at predicting early revascularization and improving efficacy of resource utilization.

Methods

Patients with CAD on CT coronary angiography (CTCA) were enrolled in an international multicenter registry. Patients with non-evaluable FFRCT analysis were excluded. The CTCA was assessed for: stenosis severity as per CAD-Reporting and Data System (CAD-RADS), lesion length and lesion-specific FFRCT measured 2 cm distal to stenosis. Risk factors and actual treatment (revascularization vs medical therapy) at 90-day follow-up were recorded. Multivariable logistic regression analysis for early revascularization was conducted. The incremental discrimination for revascularization prediction was compared among 3 models (model 1: risk factors + lesion length and location + CAD-RADS; model 2: model 1 + lesion-specific FFRCT; model 3: model 2 + ΔFFRCT). Simulating ICA referral for patients with CAD-RADS ≥3 and lesion-specific FFRCT ≤0.8, the potential impact of ΔFFRCT at reducing ICA referral and improving the ratio of subsequent revascularization was assessed.

Results

Of 4730 patients (66±10 years; 34% female), 2092 (42.7%) underwent ICA and 1168 (24.7%) underwent early revascularization. With increasing ΔFFRCT, a higher incidence of revascularization (Figure 1A) and an increase in the revascularization to ICA ratio was observed (Figure 1B). ΔFFRCT >0.13 was the optimal cut-off for predicting revascularization as determined by the Youden index. ΔFFRCT remained an independent predictor for early revascularization (odds ratio per 0.05 increase with 95% CI, 1.31 [1.26–1.35]; p<0.0001) after adjusting for risk factors, CAD-RADS, lesion length and location, and FFRCT. Among the 3 models, model 3, which included ΔFFRCT showed the highest AUC and improved discrimination power compared to model 2 (0.87 [0.86–0.88] vs 0.85 [0.84–0.86]; p<0.0001] (Figure 2), with the greatest incremental value for ΔFFRCT observed in patients with lesion-specific FFRCT between 0.71–0.80. In patients with CAD-RADS ≥3 and lesion-specific FFRCT ≤0.8, a diagnostic strategy incorporating ΔFFRCT >0.13 would potentially reduce ICA referral by 32.2% (1638 to 1110) and improve the revascularization to ICA ratio from 65.2% [1068/1638] to 73.1% [811/1110].

Conclusions

The characterization of CAD with ΔFFRCT improves the identification of patients requiring early revascularization as compared to a standard diagnostic strategy of CTCA with FFRCT, particularly for those with lesion-specific FFRCT of 0.71–0.80. ΔFFRCT has the potential to aid decision making for ICA referral and improve the efficiency of resource utilization.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): HeartFlow, Inc., Redwood City, CA, USA ΔFFRCT and actual treatmentROC curve for early revascularization

Transcatheter mitral valve-in-valve implantation: a 10-year single center experience

Background

Transcatheter mitral valve-in-valve (TMVIV) appears a reasonable alternative to surgical redo mitral valve replacement in patients with degenerated mitral prosthesis and high surgical risk with favorable early and mid-terms outcomes. Long-term outcomes are limited by high mortality in a comorbid population.

Purpose

We aimed to evaluate early prosthesis hemodynamic performance and late clinical outcomes following TMVIV.

Methods

All patients who underwent TMVIV for degenerated surgical mitral bioprostheses from 2011 to 2020 in our center were included. Prospectively collected demographic, clinical, procedural, and imaging variables were analyzed. Clinical and echocardiographic outcomes were defined according to Mitral Valve Academic Research Consortium (MVARC) definitions and assessed at 30-day and at the latest follow-up available.

Results

A total of 67 patients were included; mean age 76.9±9.6 years, mean STS score 11.0±6.2%, 53.7% male (n=36). Mechanisms of bioprosthetic failure were mitral stenosis (n=32, 47.8%), mitral regurgitation (n=24, 35.8%), and mixed (n=11, 16.4%). Mean time from mitral valve surgery to TMVIV was 10.2±4.3 years. Access was mostly transapical (n=45; 67.2%), followed by transseptal (n=22; 32.8%). Following the first transseptal procedure in 2016; transseptal access accounted for the majority of procedures (22 of 37 cases, 59.4%).

Technical success was achieved in 65 patients (97.0%). Mean hospitalization was 9.2±10.0 days; shorter with the transseptal as opposed to the transapical approach (6.3±8.1 days versus 11.0±10.5 days, p=0.001). At 30-day echographic follow-up, mean mitral valve gradient was 7.3±2.7 and 1 patient (1.9%) had mitral regurgitation >mild.

At 30-day follow-up, 3 patients had died (4.5%); due to left ventricular outflow tract obstruction (1), heart failure (1), and stroke (1). New pacemakers were required in 2 patients (3.0%) and pacemaker lead dislodgement occurred in 1 patient (1.5%), 4 patients (6.2%) were hospitalized for heart failure. At a median follow-up of 3.8 years [1.7–5.1], 29 patients had died (43.3%), valve thrombosis was found in 6 (8.9%) and endocarditis in 4 patients (6.2%). Mitral valve reintervention was performed in 4 patients (6.2%); redo TMVIV due to valve migration in 1 (1.9%), surgical valve replacement in 1 (1.9%), and delayed redilation with a non-compliant balloon due to underexpansion in 2 patients (3.8%).

Conclusion

TMVIV is associated with acceptable 30-day mitral valve hemodynamics. Long-term mortality remains high in this high-surgical risk comorbid group.

Funding Acknowledgement

Type of funding sources: None.

Increased classical monocyte subsets in South Asians compared to White Caucasians at risk for coronary atherosclerosis

Background

South Asians (SA) have an increased prevalence of coronary artery disease (CAD) and myocardial infarction compared with age- and sex-adjusted White Caucasians (WC). The mechanism for this increased risk is poorly understood. While classical CD14++CD16- monocytes act as independent predictors of cardiovascular disease, differences in the distribution of monocyte subsets between SA and WC have not been established.

Purpose

We aimed to determine if differences exist in monocyte subsets between SA and WC at risk for CAD.

Methods

Our cohort consisted of 119 consecutively enrolled patients (59 SA, 60 WC) at intermediate or higher risk for CAD by the INTERHEART score using self-reported history and physical exam. A single blood sample was collected prospectively for the purpose of monocyte analysis. Flow cytometry using dual colour fluorescence (CD14, CD16) within the monocyte gate was used to identify monocyte subsets (classical, intermediate and non-classical) by staff blinded to the individuals' characteristics.

Variables were compared using Mann-Whitney U test and Chi-squared test, as appropriate. Eta coefficient was calculated to analyze the relationship between ethnicity and proportion of monocyte subsets. Eta squared values were calculated to assess the impact of ethnicity on monocyte subset proportions.

Results

The SA group consisted of 64% males with a mean age of 54 (± 9), while the WC group consisted of 55% males with a mean age of 59 (± 7). Both groups had similar body mass index, rates of hypertension, dyslipidemia and family history of premature CAD. Compared to WC, SA had higher prevalence of diabetes (36% vs. 13%, p=0.005) and hemoglobin A1C levels (6.0±1.1% vs. 5.6±0.6%, p<0.001). SA patients had a higher proportion (85.3±10.7% vs. 81.4±11.0%, p=0.009) and total level (449.0±180.4 vs. 388±127.4, p=0.010) of classical CD14++CD16- monocytes compared to WC. There was no difference between the two groups in the proportion of intermediate CD14++CD16+ and non-classical CD14+CD16++ monocytes. There was no association between diabetes and the proportion of monocyte subsets. Ethnicity had a moderate association with the proportion of classical CD14++CD16- monocytes (Eta coefficient = 0.525) with a large effect size (Eta squared = 27.5%). The association of ethnicity with intermediate CD14++CD16+ and non-classical CD14+CD16++ monocytes was either weak or negligible with minimal to no effect size.

Conclusion

In patients with substantive risk for CAD, SA had a significantly higher proportion and level of classical CD14++CD16- monocytes compared to WC. Our findings provide a novel insight into the potential mechanism of increased CAD susceptibility amongst SA compared to WC. Future studies are needed to determine whether these ethnic differences in the distribution of monocyte subsets can predict susceptibility to developing CAD and suffering atherothrombotic events.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Cardiology Academic Practice Plan grant at the University of British Columbia

Thrombus formation on bioprosthetic aortic valves

Background

18F-GP1 is a novel radiotracer with a high affinity for the platelet glycoprotein IIb/IIIa receptor. Subclinical bioprosthetic valve thrombus has been postulated as a trigger for accelerated valve degeneration.

Purpose

To determine the feasibility of 18F-GP1 positron-emission tomography-computed tomography (PET-CT) for the detection of subclinical bioprosthetic aortic valve thrombus.

Methods

(i) Explanted degenerated aortic valve prostheses underwent histology and imaging. (ii) In a prospective observational study, patients with bioprosthetic aortic valve replacement (AVR) underwent echocardiography and 18F-GP1 PET-CT. Valves were assessed for hypoattenuating leaflet thickening (HALT), hypo-attenuation affection leaflet motion (HAM) and GP1 uptake.

Results

(i) GP1 correlated with thrombus on explanted valves (Figure). (ii) The first 6 patients (Table) were asymptomatic and had normally functioning surgical bioprostheses on echocardiography. At a median of 166 (range 122–189) days post-AVR, no patients had HALT or HAM on CT. There was avid focal GP1 uptake on the leaflets of all 6 patients which appeared most prominent along the leaflet edges (Figure). Only one patient had focal uptake in the valve frame, remote from the leaflets. In a separate cohort undergoing 18F-GP1 PET-CT for other conditions, there was no uptake on normal, native aortic valves (n=8).

Conclusion

For the first time, we demonstrate that 18F-GP1 PET-CT is a highly sensitive method of assessing platelet activation on bioprosthetic aortic valves. Despite the absence of CT evidence, early thrombus appeared to be a universal finding on recently implanted valve prostheses. The biological and clinical implications of subclinical bioprosthetic aortic valve thrombus have yet to be established.

GP1 uptake in AVR

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Geometrical predictors of small virtual neoLVOT size in functional mitral regurgitation

Background

LVOT obstruction is a potentially lethal complication of transcatheter mitral valve replacement (TMVR). An anticipated neoLVOT area of <2cm2 is presumed to imply prohibitive risk. Measurement of the anticipated neoLVOT can be time consuming and requires specialist software to facilitate virtual valve implantation.

Purpose

To determine simple geometrical predictors of prohibitive neoLVOT size.

Methods

165 consecutive, non-calcific FMR patients referred to a transcatheter heart valve program were analysed. Segmentation of the mitral annulus and left heart geometry was performed using CT. Suitability for a default D-shaped TMVR was determined by proprietary annular inclusion criteria. Systolic neoLVOT area was determined via virtual valve implantation of the default TMVR.

Results

Sufficient image data for annular and neoLVOT suitability assessment was available in 152 patients. 105 patients (69%) were suitable for TMVR based on annular measurements. Of these, neoLVOT area was >2cm2 in 88 (84%). Overall, compared to patients not suitable for TMVR (n=64), those suitable had larger ventricles with lower LVEF, and larger annuli (table 1). Using binomial logistic regression involving the variables within table 1, LVESD was the sole statistically significant variable to predict neoLVOT area of <2cm2 (p=0.02). LVESD <48mm had 82% sensitivity and 94% specificity for the presence of prohibitive neoLVOT (figure 1).

Conclusion

Smaller LVESD is a strong predictor of small neoLVOT, and hence LVOT obstruction post default D-shaped TMVR implantation. This simple measure may therefore be used to streamline patient selection for advanced pre-procedural imaging analysis.

Predicting NeoLVOT size <2 cm2

Funding Acknowledgement

Type of funding source: None

P2238Prognostic value and incremental benefit of ischaemic myocardial burden subtended by non-invasive CT-derived fractional flow reserve (FFRCT) significant stenoses

Background

Fractional flow reserve derived from CT-coronary angiography (FFRCT) accurately identifies ischaemic vessels which may be associated with clinical outcomes. Its predictive value in grey zone FFRCT values between 0.7–0.8 is not defined. The technique permits estimation of burden of ischaemic myocardium subtended by FFRCT significant vessels.

Purpose

To evaluate the prognostic value and incremental benefit of FFRCT defined ischaemic myocardial burden when compared to FFRCT alone.

Methods

This is a subanalysis of NXT (Analysis of Coronary Blood-Flow Using CTA:Next-Steps), a prospective study of stable coronary artery disease (CAD) patients referred for invasive angiography (ICA) undergoing invasive FFR, CTA and FFRCT in whom treating physicians had been blinded to FFRCT results. Primary endpoint, defined as a composite of non-fatal myocardial infarction and any revascularisation, was determined in 206 patients (age 64±9.5 years, 64% male) and 618 vessels. Burden of ischaemic myocardium was defined as percentage of myocardium subtended beyond the point at which a vessel's FFRCT becomes ≤0.8 as estimated by APPROACH score (FFRCT-APPROACH). In significant FFRCT vessels, the predictive value and incremental benefit of FFRCT-APPROACH was compared with significant FFRCT (≤0.8) for primary endpoint as measured by area under the receiver operator characteristic curve (AUC). Significant ischaemic myocardial burden was defined as >10%. The incidence and relationship between the primary endpoint with each 10% increase in FFRCT-APPROACH and 0.05-unit decrease in FFRCT values ≤0.8 was determined.

Results

Significant FFRCT was identified in 52.9% of patients (109/206) and 29.3% of vessels (181/618). At 4.7 years median follow-up the incidence of the primary endpoint in vessels with significant FFRCT-APPROACH was 58.9% (96/163) which was comparable with vessels with significant FFRCT (55.2%,100/181; P=0.50). The predictive value of FFRCT-APPROACH for the primary endpoint was comparable with FFRCT (AUC 0.72 [95% CI 0.65–0.79] vs 0.71 [0.63–0.78], P=0.79). When combined, there was significant predictive improvement compared with FFRCT alone (AUC 0.77 [0.70–0.84]; P=0.01). The largest incremental benefit upon FFRCT was observed in vessels with FFRCT values in the grey zone between 0.70–0.80 (AUC 0.76 [0.65–0.86] vs 0.62 [0.48–0.74]; P<0.01). Each 10% increase in FFRCT-APPROACH (Adjusted-HR 1.36; 95% CI 1.16–1.60; P<0.001) and each 0.05-unit FFRCT decrease (Adjusted-HR 1.42; 1.19–1.70; P<0.001) were independently associated with significant increase in the incidence of the primary-endpoint.

Conclusion

In patients with stable CAD referred for ICA, the burden of ischaemic myocardium subtended by FFRCT significant vessels predicted non-fatal myocardial infarction and future revascularisation. This provided significant incremental benefit when used in combination with FFRCT particularly at FFRCT values in the grey zone between 0.7 to 0.8.

P6319CT derived fractional flow reserve (FFRct) for functional coronary artery evaluation in the follow-up of patients after heart transplantation

Background

Cardiac allograft vasculopathy (CAV) remains a leading cause of morbidity and mortality after heart transplantation. Annual screening is recommended to improve risk stratification and early treatment of CAV and is often performed with invasive coronary angiography (ICA). Coronary computed tomography angiography (CCTA) with CCTA-derived fractional flow reserve (FFRct) might be a non-invasive alternative to ICA for the surveillance of CAV providing both anatomical and functional information.

Purpose

To describe our initial results with CCTA and FFRct for detection of CAV in a cohort of heart transplant patients.

Methods

Heart transplant patients who underwent CCTA with FFRct as part of routine annual assessment for CAV were enrolled in a prospective registry from February 2018 to February 2019 in a single center. The most recently known CAV score (0–3) based on invasive angio and single photon emission computed tomography (SPECT) before CCTA was recorded. CCTA image quality was scored as non-diagnostic, moderate, good or excellent. FFRct analysis was performed off-site by a commercial company. For each coronary stenosis >30%, an FFRCTvalue distal to the stenosis was measured. For the RCA, LAD and CX without a stenosis, the FFRct value in the most distal location in the vessel was recorded. CAV classification was rescored based on CCTA. Demographics, additional diagnostic tests, and treatment plans were evaluated including major adverse events (MACE) during 90-day follow-up.

Results

65 patients (56 (39–65) years (median/ 25th–75thpercentile), 40% women) that were 11 (7–16) years after transplantation were included. The most recent CAV score was 0 in 52 patients (80%) and 1 or 2 in 13 patients. CCTA image quality was good or excellent in 59 (91%) patients. CCTA reclassified CAV scores in 32 (49%) patients to 33 patients with CAV 0, 18 patients with CAV 1, 9 patients with CAV 2 and 5 patients with CAV 3. In 17 patients (26%) at least one stenosis with FFRct ≤0.80 was detected including 11 patients with single vessel disease, 5 with two-vessel disease and one with three-vessel disease. In the 48 patients without a focal stenosis, mean distal FFRct values were 0.88 (0.86–0.91), 0.87 (0.85–0.90) and 0.90 (0.86–0.91) at less than 10, 10–15 or more than 15 years after transplantation, respectively (p=0.457). Additional tests were performed in 10 (15%) patients (1 SPECT and 10 invasive coronary angiographies), which resulted in revascularization by PCI in 6 (9%) patients. No MACE occurred during 90-day follow-up.

Conclusion

CCTA with FFRct can be successfully performed in heart transplant patients, detects patients with significant coronary stenosis and CCTA leads to substantial reclassification of CAV grades.

Acknowledgement/Funding

FFRct analysis was performed as part of the ADVANCE registry which is supported by Heartflow Inc.

P3432Coronary artery calcium score is of limited sensitivity in detecting subclinical atherosclerosis in young individuals with family history of coronary artery disease

Introduction

Family history of premature coronary artery disease (CAD) is known to predispose individuals to adverse CAD events, often at a younger age. Current risk stratification strategy is suboptimal, as up to 50% of individuals were considered “low-risk” prior to their first presentation of myocardial infarction. Coronary artery calcium score (CACS) is a marker of atherosclerosis and provides incremental value in risk stratification. However, the utility of CACS may be limited in younger patients as they often have non-calcified atherosclerotic plaques. In this study, we evaluate the sensitivity of CACS in detecting subclinical atherosclerosis in different age groups.

Method

From 310 referrals to a specialized unit in the management of early atherosclerosis, 222 individuals with a family history of premature CAD (defined as CAD events in first-degree family members, male<55 and female<65) and aged between 35 and 55 were enrolled for assessment of their CAD risks. Individuals with possible, probably or definite familial hypercholesterolemia were excluded. In addition to clinical and risk factor evaluation, cardiac CT and CACS were performed in select individuals, at the discretion of the treating physician.

Results

Of the 141 (59% male, mean age 45.9±6.0 year) individuals that completed clinical evaluation, 65 (73% male, mean age 47.4±6.9 years) have subclinical atherosclerosis (defined by the presence of atherosclerotic plaques in any of the coronary artery segments in cardiac CT). Of them, 52 have CACS>0, giving an overall sensitivity of 80%. The breakdown by age group is shown in table 1. The sensitivity of CACS in detecting subclinical atherosclerosis is quite modest in younger individuals (60% in individuals <45 year-old) but improves with patient age (>85% in >45 years).

Table 1. Sensitivity of CACS in different age groups Age group True Positive Fast Negative Sensitivity N (CAC+ CTCA+) (CAC+ CTCA−) (%) <40 6 4 60 10 41–45 7 4 55 11 46–50 19 3 86 22 51–55 20 1 95 21

Conclusion

In younger individuals (<45 years) with family history of premature CAD, CACS is of limited sensitivity in detecting subclinical atherosclerosis, and should not be used to rule out CAD. Further studies are warranted.

P3412Risk factors, biomarkers and framingham risk estimate fail to identify presence of subclinical atherosclerosis in young individual with family history of premature coronary artery disease

Introduction

Patients with family history of premature coronary artery disease (CAD) are at increased risk of CAD events at a younger age. Risk factor based approaches and clinical evaluation are most commonly used to assess these individuals. However, it has been recently shown that up to 50% of individual presenting with their first myocardial infarction (MI) were considered to be “low risk” prior to that event. MI is often a result of plaque rupture preceded by progression of subclinical atherosclerosis. Detection of subclinical atherosclerosis may therefore help target prevention of plaque progression. We assessed the value of clinical risk factor, biomarkers and Framingham Risk Score (FRS) in predicting subclinical atherosclerosis in individuals with a family history of premature CAD.

Methods

From 310 referrals, 222 individuals between the ages of 35 and 55 with a family history of premature CAD (CAD events in first-degree family members (male <55, female <65)) were enrolled for evaluation of risk of CAD. Those with familial hypercholesteremia (possible, probable or definite) were excluded. Patients underwent clinical and risk factor evaluations as well as Cardiac CT or Calcium Score (CS) to assess presence of subclinical / clinical atherosclerosis at the discretion of the treating physician.

Results

In this pilot, 141 individuals (59% male, mean age 45.9±6.0 years) completed evaluation, and 65 (46%) had evidence of subclinical atherosclerosis on CT coronary angiography or CT calcium score with a mean segment involvement score (SIS) of 2.8 and mean CS of 152, putting them above the 80th percentile for their age and sex. Aside from male sex, age, and smoking history, other traditional risk factors and biomarkers including diabetes mellitus, hypertension, total cholesterol, LDL-C, HDL-C and Cholesterol/HDL-C were not significantly different between those with or without subclinical atherosclerosis (Table 1).

Table 1

Conclusion

In young individuals with a family history of premature CAD, risk factors, biomarkers, and FRS failed to identify individuals with premature, subclinical atherosclerosis in this pilot study. Detection of subclinical atherosclerosis and early implementation of treatment with the aim of stabilizing plaques and stopping progression might prove vital in reducing events in these individuals. Further studies are warranted.

Independent association of subclinical coronary artery disease and emphysema in HIV-infected patients

OBJECTIVES

Chronic obstructive pulmonary disease (COPD) and coronary artery disease are inflammatory states with a significant clinical impact. The relationship between them has not been investigated in patients with HIV infection. We assessed the presence of subclinical emphysema and coronary artery disease using chest computed tomography (CT) imaging in a cohort of HIV-infected patients receiving antiretroviral therapy.

METHODS

Gated chest CT scans were performed in 1446 consecutive patients to assess the presence and severity of coronary artery calcium (CAC) (classified as a score of 0, 1-100 or > 100) and emphysema (classified using a visual semiquantitative scale: 0, absent; 1-4, mild to moderate; > 4, severe). Univariable and multivariable logistic regression analyses were performed to identify factors independently associated with CAC and emphysema.

RESULTS

The emphysema score was significantly higher in patients with CAC scores of 1-100 and > 100 compared with those with a CAC score of 0. After adjustments for age, sex, smoking status, pack-years of smoking, visceral adiposity and duration of HIV infection, the presence of any emphysema was significantly associated with a CAC score > 0 [odds ratio (OR) 1.43; 95% confidence interval (CI) 1.08-1.88; P = 0.012]. The association persisted after adjustment for the Framingham risk score (OR 1.52; 95% CI 1.16-1.99; P = 0.002). There was a dose-dependent effect in the association between emphysema score and CAC score.

CONCLUSIONS

In this cross-sectional study of HIV-infected patients, there was an independent association between emphysema and CAC, after adjustment for traditional cardiovascular risk factors, suggesting a common pathogenesis of these chronic inflammatory conditions in a chronic inflammatory disease such as HIV infection.

Incremental diagnostic value of epicardial adipose tissue for the detection of functionally relevant coronary artery disease

BACKGROUND AND AIM

To determine the incremental diagnostic value of epicardial adipose tissue (EAT) volume in addition to the coronary artery calcium (CAC) score for detecting hemodynamic significant coronary artery disease (CAD).

METHODS AND RESULTS

122 patients (mean age 61 ± 10 years, 61% male) without a previous cardiac history underwent a non-contrast CT scan for calcium scoring and EAT volume measurements. Subsequently all patients underwent invasive coronary angiography (ICA) in conjunction with fractional flow reserve (FFR) measurements. A stenosis >90% and/or a FFR ≤0.80 were considered significant. Mean EAT volume and CACscore were 128 ± 51 cm(3) and 418 ± 704, respectively. The correlation between EAT volume and the CACscore was poor (r = 0.11, p = 0.24). Male gender (odds ratio [OR] 2.86, p = 0.01), CACscore ([cut-off value 100] OR 3.31, p = 0.003, and EAT volume ([cut-off value 92 cm(3)] OR 4.28, p = 0.01) were associated with flow-limiting disease. The multivariate model revealed that only male gender (OR 2.50, p = 0.045), CAC score (OR 3.60, p = 0.005), and EAT volume (OR 4.95, p = 0.02) were independent predictors of myocardial ischemia. Using the cut-off values of 100 (CAC score) and 92 cm(3) (EAT volume), sensitivity, specificity, negative predictive value, positive predictive value, and accuracy for detecting functionally relevant CAD as indicated by FFR were 71, 57, 77, 50 and 63% and 91, 29, 85, 44 and 52% for the CACscore and EAT volume, respectively. Adding EAT volume to the CAC score and cardiovascular risk factors did not enhance diagnostic performance for the detection of significant CAD (p = 0.57).

CONCLUSION

EAT volume measurements have no diagnostic value beyond calcium scoring and cardiovascular risk factors in the detection of hemodynamic significant CAD.

Characteristics of COPD in never-smokers and ever-smokers in the general population: results from the CanCOLD study

BACKGROUND

There is limited data on the risk factors and phenotypical characteristics associated with spirometrically confirmed COPD in never-smokers in the general population.

AIMS

To compare the characteristics associated with COPD by gender and by severity of airway obstruction in never-smokers and in ever-smokers.

METHOD

We analysed the data from 5176 adults aged 40 years and older who participated in the initial cross-sectional phase of the population-based, prospective, multisite Canadian Cohort of Obstructive Lung Disease study. Never-smokers were defined as those with a lifetime exposure of <1/20 pack year. Logistic regressions were constructed to evaluate associations for 'mild' and 'moderate-severe' COPD defined by FEV1/FVC <5th centile (lower limits of normal). Analyses were performed using SAS V.9.1 (SAS Institute, Cary, North Carolina, USA).

RESULTS

The prevalence of COPD (FEV1/FVC<lower limits of normal) in never-smokers was 6.4%, constituting 27% of all COPD subjects. The common independent predictors of COPD in never-smokers and ever-smokers were older age, self reported asthma and lower education. In never-smokers a history of hospitalisation in childhood for respiratory illness was discriminative, while exposure to passive smoke and biomass fuel for heating were discriminative for women. COPD in never-smokers and ever-smokers was characterised by increased respiratory symptoms, 'respiratory exacerbation' events and increased residual volume/total lung capacity, but only smokers had reduced DLCO/Va and emphysema on chest CT scans.

CONCLUSIONS

The study confirmed the substantial burden of COPD among never-smokers, defined the common and gender-specific risk factors for COPD in never-smokers and provided early insight into potential phenotypical differences in COPD between lifelong never-smokers and ever-smokers.

TRIAL REGISTRATION NUMBER

NCT00920348 (ClinicalTrials.gov); study ID number: IRO-93326.