Sex differences in the visual-functional mismatch between coronary angiography or intravascular ultrasound versus fractional flow reserve

Gender-Based Specificities of Fractional Flow Reserve Measurement

BACKGROUND

The relationship between angiographic findings and fractional flow reserve (FFR) according to gender is currently unknown.

AIMS

To examine gender-based differences in the concordance between angiographic and functional assessment of coronary stenosis severity.

METHODS

We examined 3770 coronary stenoses of stable patients undergoing both quantitative coronary angiography and FFR measurements in at least one coronary stenosis.

RESULTS

Median FFR values were higher in female as compared with male patients (0.84 vs. 0.81, p < 0.001) in the overall cohort and in the first three quartiles of diameter stenosis (DS). At receiver operator characteristics (ROC) analysis, DS was effective in predicting ischemic FFR values in both men and women. A 50% DS was the optimal cut off to identify functionally significant stenoses in the entire cohort and in male patients. In females, a higher DS threshold (≥ 59%) significantly improved lesions classification (69.4% vs. 72.4%, p = 0.034), yet at the cost of an increased false negatives rate (10.5% vs. 20.8%, p < 0.001). A lower cut-off of 50% showed a superior diagnostic accuracy for ischemic FFR values (i.e., FFR values ≤ 0.80, AUC: 0.697 vs. 0.661, p = 0.006). Female gender was independently associated with a reduced risk of ischemic FFR (OR 0.51 95% CI [0.43-0.61]).

CONCLUSIONS

Female patients show higher FFR values across different DS thresholds compared to male patients. A DS ≥ 50% is the best threshold to identify ischemic FFR in both males and females. A higher threshold of DS (≥ 59%) is associated with a significant improvement in lesion classification, despite leading to increased false negatives rate.

Sex Differences in Patients Undergoing FFR-Guided PCI or CABG in the FAME 3 Trial

BACKGROUND

Outcomes in women after fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) using current-generation drug-eluting stents (DES) compared with coronary artery bypass grafting (CABG) are unknown.

OBJECTIVES

This study sought to evaluate differences in clinical outcomes according to sex after FFR-guided PCI with current generation DES compared with CABG.

METHODS

The FAME 3 (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation) trial was an investigator-initiated, randomized controlled trial, comparing FFR-guided PCI with current generation DES or CABG in patients with 3-vessel coronary artery disease. This prespecified subgroup analysis compared the incidence of major adverse cardiac and cerebrovascular events (MACCE) according to sex, defined as the composite of all-cause death, myocardial infarction, stroke, or repeat revascularization at 3 years.

RESULTS

Of 1,500 patients included in the FAME 3 trial, 265 (17.7%) were women. Women had a significantly higher risk of MACCE at 3 years compared with men after CABG (18.1% vs 11.7%; adjusted HR: 2.07; 95% CI: 1.19-3.60), whereas women had a similar risk of MACCE at 3 years compared with men after PCI (18.2% vs 19.1%; adjusted HR: 1.27; 95% CI: 0.79-2.03). Regarding treatment effects by sex, women undergoing PCI had a similar risk of MACCE at 3 years compared with CABG (adjusted HR: 1.15; 95% CI: 0.62-2.11). By contrast, men undergoing PCI had a higher risk of MACCE at 3 years compared with CABG (adjusted HR: 1.68; 95% CI: 1.25-2.25; Pinteraction = 0.142), which was mainly driven by a higher risk of myocardial infarction (adjusted HR: 2.11; 95% CI: 1.26-3.56; Pinteraction = 0.102) and repeat revascularization (adjusted HR: 2.26; 95% CI: 1.47-3.47; Pinteraction = 0.071).

CONCLUSIONS

In the FAME 3 trial, at 3 years, women had similar outcomes with FFR-guided PCI compared with CABG, whereas men had improved outcomes with CABG. (A Comparison of Fractional Flow Reserve-Guided Percutaneous Coronary Intervention and Coronary Artery Bypass Graft Surgery in Patients With Multivessel Coronary Artery Disease [FAME 3]; NCT02100722).

Impact of Sex in the Incidence of Heart Failure in Patients with Chronic Coronary Syndrome

PURPOSE OF REVIEW

This review examines the available evidence concerning the incidence of heart failure in patients with chronic coronary syndrome, with a focus on gender differences.

RECENT FINDINGS

The incidence of heart failure in the context of chronic coronary syndrome presents conflicting data. Most of the available information stems from studies involving stable patients' post-acute coronary syndrome, revealing a wide range of incidence rates, from less than 3% to over 20%, observed over 5 years of follow-up. Regarding the gender differences in heart failure incidence, there is no consensus about whether women exhibit a higher incidence, particularly in the presence of evidence of obstructive coronary artery disease. However, in cases where obstructive coronary artery disease is absent, women may face a more unfavourable prognosis due to a higher prevalence of microvascular disease and heart failure with preserved ventricular function. The different profile of ischaemic heart disease in women difficult to establish differences in prognosis independently associated with female sex. Targeted investigations are essential to discern the incidence of heart failure in chronic coronary syndrome and explore potential gender-specific associations.

Intravascular Imaging-Guided Optimization of Complex Percutaneous Coronary Intervention by Sex: A Subgroup Analysis of the RENOVATE-COMPLEX-PCI Trial

Importance

There have been heterogeneous results related to sex differences in prognosis after percutaneous coronary artery intervention (PCI) for complex coronary artery lesions.

Objective

To evaluate potential differences in outcomes with intravascular imaging-guided PCI of complex coronary artery lesions between women and men.

Design, Setting, and Participants

This prespecified substudy evaluates the interaction of sex in the investigator-initiated, open-label, multicenter RENOVATE-COMPLEX-PCI randomized clinical trial, which demonstrated the superiority of intravascular imaging-guided PCI compared with angiography-guided PCI in patients with complex coronary artery lesions. The trial was conducted at 20 sites in Korea. Patients with complex coronary artery lesions undergoing PCI were enrolled between May 2018 and May 2021, and the median (IQR) follow-up period was 2.1 (1.4-3.0) years. Data were analyzed from December 2022 to December 2023.

Interventions

After diagnostic coronary angiography, eligible patients were randomly assigned in a 2:1 ratio to receive intravascular imaging-guided PCI or angiography-guided PCI. The choice and timing of the intravascular imaging device were left to the operators' discretion.

Main Outcomes and Measures

The primary end point was target vessel failure, defined as a composite of cardiac death, target vessel-related myocardial infarction, or clinically driven target vessel revascularization. Secondary end points included individual components of the primary end point.

Results

Of 1639 included patients, 339 (20.7%) were women, and the mean (SD) age was 65.6 (10.2) years. There was no difference in the risk of the primary end point between women and men (9.4% vs 8.3%; adjusted hazard ratio [HR], 1.39; 95% CI, 0.89-2.18; P = .15). Intravascular imaging-guided PCI tended to have lower incidence of the primary end point than angiography-guided PCI in both women (5.2% vs 14.5%; adjusted HR, 0.34; 95% CI, 0.15-0.78; P = .01) and men (8.3% vs 11.7%; adjusted HR, 0.72; 95% CI, 0.49-1.05; P = .09) without significant interaction (P for interaction = .86).

Conclusions and Relevance

In patients undergoing complex PCI, compared with angiographic guidance, intravascular imaging guidance was associated with similar reduction in the risk of target vessel failure among women and men. The treatment benefit of intravascular imaging-guided PCI showed no significant interaction between treatment strategy and sex.

Trial Registration

ClinicalTrials.gov Identifier: NCT03381872.

Impact of Sex Differences on the Outcomes of Coronary Invasive Physiological Assessment: Long-Term Follow-Up in a Brazilian Population

Objective

This study aimed to evaluate the rate of major adverse cardiac events (MACEs; the sum of death, myocardial infarction, and revascularization rates) according to interventional strategies guided by invasive physiological methods in both sexes in a Brazilian population during long-term follow-up for an average of 2 years.

Methods

This retrospective single-center study included 151 consecutive patients (232 lesions) between January 2018 and January 2022. The participants were divided into two groups: the female group (FG), comprising 59 patients with 88 lesions, and the male group (MG), comprising 92 patients with 144 lesions.

Results

The FG had a greater mean age (FG: 67.96 ± 13.12 vs. MG: 62.36 ± 12.01 years, p = 0.009) and lower mean creatinine clearance (FG: 79.35 ± 38.63 vs. MG: 92.02 ± 38.62 mL/min, p = 0.02) than did the MG. The percentage of lesions in the left main coronary artery was higher in the FG than in the MG (12.5% vs. 2.78%, p = 0.006). The mean follow-up time was longer in the MG than in the FG (795.61 ± 350 vs. 619.19 ± 318 days, respectively; p = 0.001). MACE occurred in 11.86% and 13.04% of patients in the FG and MG, respectively (p = 0.850). Secondary outcomes, such as death, reinfarction, and the need for new revascularization, showed no significant between-sex differences.

Conclusions

Our study demonstrated the safety of invasive physiological methods to determine coronary revascularization in both male and female patients in a Brazilian population, as evidenced by the low rates of adverse cardiac events and death after a long-term follow-up.

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.

Multimodality OCT, IVUS and FFR evaluation of coronary intermediate grade lesions in women vs. men

Background

The pathophysiology of atherosclerotic plaque formation and its vulnerability seem to differ between genders due to contrasting risk profiles and sex hormones, however this process is still insufficiently understood. The aim of the study was to compare the differences between sexes regarding the optical coherence tomography (OCT), intravascular ultrasound (IVUS) and fractional flow reserve (FFR)-derived coronary plaque indices.

Methods

In this single-center multimodality imaging study patients with intermediate grade coronary stenoses identified in coronary angiogram (CAG) were evaluated using OCT, IVUS and FFR. Stenoses were considered significant when the FFR value was ≤0.8. Minimal lumen area (MLA), was analyzed by OCT in addition to plaque stratification into fibrotic, calcific, lipidic and thin-cap fibroatheroma (TCFA). IVUS was used for evaluation of lumen-, plaque- and vessel volume, as well as plaque burden.

Results

A total of 112 patients (88 men and 24 women) with chronic coronary syndromes (CCS), who underwent CAG were enrolled. No significant differences in baseline characteristics were present between the study groups. The mean FFR was 0.76 (0.73-0.86) in women and 0.78 ± 0.12 in men (p = 0.695). OCT evaluation showed a higher prevalence of calcific plaques among women than men p = 0.002 whereas lipid plaques were more frequent in men (p = 0.04). No significant differences regarding minimal lumen diameter and minimal lumen area were found between the sexes. In IVUS analysis women presented with significantly smaller vessel area, plaque area, plaque volume, vessel volume (11.1 ± 3.3 mm² vs. 15.0 ± 4.6 mm² p = 0.001, 6.04 ± 1.7 mm² vs. 9.24 ± 2.89 mm² p < 0.001, 59.8 ± 35.2 mm³ vs. 96.3 (52.5-159.1) mm³ p = 0.005, 106.9 ± 59.8 mm³ vs. 153.3 (103-253.4) mm³ p = 0.015 respectively). At MLA site plaque burden was significantly greater for men than women (61.50 ± 7.7% vs. 55.5 ± 8.0% p = 0.005). Survival did not differ significantly between women and men (94.6 ± 41.9 months and 103.51 ± 36.7 months respectively; p = 0.187).

Conclusion

The presented study did not demonstrate significant differences in FFR values between women and men, yet a higher prevalence of calcific plaques by OCT and lower plaque burden at the MLA site by IVUS was found in women vs. men.

Sex-Specific Stress Perfusion Cardiac Magnetic Resonance Imaging in Suspected Ischemic Heart Disease: Insights From SPINS Retrospective Registry

BACKGROUND

Cardiovascular disease (CVD) remains the leading cause of mortality in women, but current noninvasive cardiac imaging techniques have sex-specific limitations.

OBJECTIVES

In this study, the authors sought to investigate the effect of sex on the prognostic utility and downstream invasive revascularization and costs of stress perfusion cardiac magnetic resonance (CMR) for suspected CVD.

METHODS

Sex-specific prognostic performance was evaluated in a 2,349-patient multicenter SPINS (Stress CMR Perfusion Imaging in the United States [SPINS] Study) registry. The primary outcome measure was a composite of cardiovascular death and nonfatal myocardial infarction; secondary outcomes were hospitalization for unstable angina or heart failure, and late unplanned coronary artery bypass grafting.

RESULTS

SPINS included 1,104 women (47% of cohort); women had higher prevalence of chest pain (62% vs 50%; P < 0.0001) but lower use of medical therapies. At the 5.4-year median follow-up, women with normal stress CMR had a low annualized rate of primary composite outcome similar to men (0.54%/y vs 0.75%/y, respectively; P = NS). In contrast, women with abnormal CMR were at higher risk for both primary (3.74%/y vs 0.54%/y; P < 0.0001) and secondary (9.8%/y vs 1.6%/y; P < 0.0001) outcomes compared with women with normal CMR. Abnormal stress CMR was an independent predictor for the primary (HR: 2.64 [95% CI: 1.20-5.90]; P = 0.02) and secondary (HR: 2.09 [95% CI: 1.43-3.08]; P < 0.0001) outcome measures. There was no effect modification for sex. Women had lower rates of invasive coronary angiography (ICA; 3.6% vs 7.3%; P = 0.0001) and downstream costs ($114 vs $171; P = 0.001) at 90 days following CMR. There was no effect of sex on diagnostic image quality.

CONCLUSIONS

Stress CMR demonstrated excellent prognostic performance with lower rates of ICA referral in women. Stress CMR should be considered as a first-line noninvasive imaging tool for the evaluation of women. (Stress CMR Perfusion Imaging in the United States [SPINS] Study [SPINS]; NCT03192891).

Impact of overestimation of fractional flow reserve by adenosine on anatomical-functional mismatch

Adenosine occasionally results in overestimation of fractional flow reserve (FFR) values, compared with other hyperemic stimuli. We aimed to elucidate the association of overestimation of FFR by adenosine with anatomically significant but functionally non-significant lesions (anatomical-functional mismatch) and its influence on reclassification of functional significance. Distal-to-aortic pressure ratio (Pd/Pa) was measured using adenosine (Pd/PaADN) and papaverine (Pd/PaPAP) in 326 patients (326 vessels). The overestimation of FFR was calculated as Pd/PaADN-Pd/PaPAP. The anatomical-functional mismatch was defined as diameter stenosis > 50% and Pd/PaADN > 0.80. Reclassification was indicated by Pd/PaADN > 0.80 and Pd/PaPAP ≤ 0.80. The mismatch (n = 72) had a greater overestimation of FFR than the non-mismatch (n = 99): median 0.02 (interquartile range 0.01-0.05) versus 0.01 (0.00-0.04), p = 0.014. Multivariable analysis identified the overestimation of FFR (p = 0.003), minimal luminal diameter (p = 0.001), and non-left anterior descending artery (LAD) location (p < 0.001) as determinants of the mismatch. Reclassification was indicated in 29% of the mismatch and was more frequent in the LAD than in the non-LAD (52% vs. 20%, p = 0.005). The overestimation of FFR is an independent determinant of anatomical-functional mismatch. Anatomical-functional mismatch, specifically in the LAD, may suggest a false-negative result.

When coronary imaging and physiology are discordant, how best to manage coronary lesions? An appraisal of the clinical evidence

BACKGROUND

Discordant physiology and anatomy may occur when nonsevere angiographic stenosis has positive physiology as well as the opposite situation.

AIM

To underline the reasons behind the discrepancy in physiology and anatomy and to summarize the information that coronary imaging may add to physiology.

METHODS

A review of the published literature on physiology and intravascular imaging assessment of intermediate lesions was carried out.

RESULTS

The limitations of angiography, the possibility of an underlying diffuse disease, the presence of a "grey zone" in both techniques, the amount of myocardial mass that subtends the stenosis, and plaque vulnerability may play a role in such discrepancy. Intracoronary imaging has a poor diagnostic accuracy compared to physiology. However, it may add information about plaque vulnerability that might be useful in deciding whether to treat or not a certain lesion.

CONCLUSIONS

Coronary revascularization is recommended for patients with ischemia based on physiology. Intracoronary imaging adds information on plaque vulnerability and can help on the decision whether to revascularize or not a lesion.

Sex Differences in Coronary Function Test Results in Patient With Angina and Nonobstructive Disease

Introduction: Invasive coronary function testing (CFT) has become the recommended diagnostic tool to assess the various endotypes of coronary vasomotor dysfunction in patients with angina and no obstructive coronary artery disease (ANOCA), which has implications for therapy and prognosis. Although the expanding performance of CFT is leading to increased knowledge of coronary vasomotor dysfunction, little is known about sex-related differences in the results of comprehensive CFT.

Methods: We conducted a prospective study of all consecutive patients with ANOCA that underwent clinically indicated CFT in a tertiary interventional from February 2019 to February 2021. CFT consisted of acetylcholine testing to diagnose epicardial or microvascular spasm, and adenosine testing to diagnose CMD. CMD was defined as an index of microvascular resistance (IMR) ≥ 25 and/or coronary flow reserve (CFR) < 2.0.

Results: In total, 228 women and 38 men underwent CFT. No differences in traditional risk factors were seen, but women had a higher prevalence of migraine (45 vs. 14%, p = 0.001). Men more often had a history of percutaneous coronary intervention (12 vs. 49%, p = 0.001). We found no difference in clinical presentation. Coronary vasomotor dysfunction was present in 95% of men and 88% of women (p = 0.25), but males show more often epicardial spasm and less microvascular spasm than women (63 vs. 42% and 29 vs. 40% respectively, p = 0.039). Impaired CFR was more prevalent among females (6 vs 20%, p = 0.033). IMR [median of 23 (15–32) vs. 19 (13–25), p = 0.08] did not differ between the sexes.

Conclusion: Men undergoing CFT show a comparable prevalence of coronary vascular dysfunction as women. However, men have a higher prevalence of epicardial spasm and a lower prevalence of microvascular spasm compared with women. An impaired CFR was more often present in women, with an equally impairment of IMR.

Gender-based in vivo comparison of culprit plaque characteristics and plaque microstructures using optical coherence tomography in acute coronary syndrome

Introduction: Women perform worse after acute coronary syndrome (ACS) than men. The reason for these differences is unclear. The aim was to ascertain gender differences in the culprit plaque characteristics in ACS.

Methods: Patients with ACS undergoing percutaneous coronary intervention for the culprit vessel underwent optical coherence tomography (OCT) imaging. Culprit plaque was identified as lipid rich,fibrous, and calcific plaque. Mechanisms underlying ACS are classified as plaque rupture, erosion,or calcified nodule. A lipid rich plaque along with thin-cap fibroatheroma (TCFA) was a vulnerable plaque. Plaque microstructures including cholesterol crystals, macrophages, and microvessels were noted.

Results: A total of 52 patients were enrolled (men=29 and women=23). Baseline demographic features were similar in both the groups except men largely were current smokers (P <0.001). Plaque morphology,men vs. women: lipid rich 88.0% vs. 90.5%; fibrous 4% vs 0%; calcific 8.0% vs. 9.5% (P = 0.64). Of the ACS mechanisms in males versus females; plaque rupture (76.9 % vs. 50 %), plaque erosion (15.4 % vs.40 %) and calcified nodule (7.7 % vs. 10 %) was noted (P = 0.139). Fibrous cap thickness was (50.19 ±11.17 vs. 49.00 ± 10.71 mm, P = 0.71) and thin-cap fibroatheroma (96.2% vs. 95.0%, P = 1.0) in men and women respectively. Likewise no significant difference in presence of macrophages (42.3 % vs. 30%, P = 0.76), microvessels (73.1% vs. 60 %, P = 0.52) and cholesterol crystals (92.3% vs. 80%, P = 0.38).

Conclusion: No significant gender-based in-vivo differences could be discerned in ACS patients’ culprit plaques morphology, characteristics, and underlying mechanisms.

Research on the Method of Predicting Fractional Flow Reserve Based on Multiple Independent Risk Factors

The use of diameter stenosis (DS), as revealed by coronary angiography, for predicting fractional flow reserve (FFR) usually results in a high error rate of detection. In this study, we investigated a method for predicting FFR in patients with coronary stenosis based on multiple independent risk factors. The aim of the study was to improve the accuracy of detection. First, we searched the existing literature to identify multiple independent risk factors and then calculated the corresponding odds ratios. The improved analytic hierarchy process (IAHP) was then used to determine the weighted value of each independent risk factor, based on the corresponding odds ratio. Next, we developed a novel method, based on the top seven independent risk factors with the highest weighted values, to predict FFR. This model was then used to predict the FFR of 253 patients with coronary stenosis, and the results were then compared with previous methods (DS alone and a simplified scoring system). In addition to DS, we identified a range of other independent risk factors, with the highest weighted values, for predicting FFR, including gender, body mass index, location of stenosis, type of coronary artery distribution, left ventricular ejection fraction, and left myocardial mass. The area under the receiver-operating characteristic curve (AUC) for the newly developed method was 84.3% (95% CI: 79.2–89.4%), which was larger than 65.3% (95% CI: 61.5–69.1%) of DS alone and 74.8% (95% CI: 68.4–81.2%) of the existing simplified scoring system. The newly developed method, based on multiple independent risk factors, effectively improves the prediction accuracy for FFR.

Association of quantitative flow ratio-derived microcirculatory indices with anatomical-functional discordance in intermediate coronary lesions

Discrepancy between coronary lesion severity and functional significance has always been a relevant issue in the management of patients undergoing coronary angiography and/or revascularization. We sought to investigate the relationship between quantitative flow ratio (QFR)-derived microcirculatory indices and anatomical-functional mismatch/reverse mismatch in intermediate coronary lesions. Intravascular ultrasound (IVUS) imaging and QFR were analyzed in 117 de novo intermediate coronary lesions. Lesions with QFR ≤ 0.8 were considered hemodynamically significant. Anatomical significance of the lesions was defined according to the best cutoff value of combined IVUS parameters for predicting QFR ≤ 0.8. QFR-derived microcirculatory indices including contrast-flow QFR minus fixed-flow QFR (cQFR-fQFR), hyperemic flow velocity and angiography-derived index of microcirculatory resistance (IMR_angio) were calculated. The best cutoff values of IVUS parameters for predicting QFR ≤ 0.8 were minimum lumen area (MLA) 3.1mm² and plaque burden (PB) 70%, with area under the curve of 0.635 and 0.703, respectively. The total discordance rate of lesion functional significance between IVUS and QFR assessments was 26.5%, with 21 lesions (17.9%) being classified as mismatch (MLA ≤ 3.1mm² and PB ≥ 70% and QFR > 0.8) and 10 lesions (8.5%) as reverse-mismatch (MLA > 3.1 mm² or PB < 70% and QFR ≤ 0.8). At multivariate analysis, IMR_angio was identified as an independent predictor of mismatch (OR1.675, 95%CI:1.176-2.386, P = 0.004), whereas hyperemic flow velocity was identified as an independent predictor of reverse-mismatch (OR 1.233, 95%CI:1.073-1.416, P = 0.003). In intermediate coronary lesions, although MLA 3.1mm² and PB 70% determined by IVUS are predictive of QFR-defined functional significance, the discordance rate remains substantial. QFR-derived microcirculatory indices are independently associated with anatomical-functional discordance between IVUS and QFR assessments.

Predictors of discordance between fractional flow reserve and resting full-cycle ratio in patients with coronary artery disease: Evidence from clinical practice

BACKGROUND

Fractional flow reserve (FFR) is an established method for assessing functional myocardial ischemia. Recently, the resting full-cycle ratio (RFR) has been introduced as a non-hyperemic index of functional coronary stenosis. However, the effects of clinical characteristics on discordance between RFR and FFR have not been fully evaluated. We aimed to identify clinical characteristics that influence FFR-RFR concordance.

METHODS

We included 410 patients with 573 intermediate coronary lesions who underwent clinically indicated invasive coronary angiography, as well as assessments of FFR and RFR. Receiver-operating characteristic (ROC) curves were created to assess the optimal cut-off values of RFR for predicting FFR ≤0.80.

RESULTS

RFR exhibited a strong correlation with FFR (r = 0.66, p < 0.0001). ROC analysis identified an optimal RFR cut-off value of 0.92 for categorization based on an FFR cut-off value of 0.8. The discordance of FFR >0.8 and RFR ≤0.92 (high FFR/low RFR) was observed in 112 lesions (20.9%), whereas the discordance of FFR ≤0.8 and RFR >0.92 (low FFR/high RFR) was observed in 35 lesions (6.5%). Higher rate of hemodialysis and lower hemoglobin levels were observed in the high FFR/low RFR group. Multivariate analyses identified female sex, left anterior descending artery (LAD) lesions, and hemodialysis as significant predictors of high FFR/low RFR. Conversely, body surface area and non-LAD lesions were significantly associated with low FFR/high RFR. Hemodialysis [odds ratio (OR): 2.41, 95% confidence interval (CI) 1.31-4.41; p = 0.005] and LAD lesions (OR: 1.86, 95% CI: 1.25-2.79; p = 0.002) were identified as independent predictors of overall FFR-RFR discordance.

CONCLUSIONS

RFR exhibited good diagnostic performance in the identification of functionally significant stenosis. However, RFR may overestimate functional severity in patients undergoing hemodialysis or in those with LAD lesions. Further prospective trials are required to demonstrate the non-inferiority of RFR to FFR.

Effect of Sex Difference on Discordance Between Instantaneous Wave-Free Ratio and Fractional Flow Reserve

BACKGROUND

Physiology-guided percutaneous coronary intervention (PCI) has demonstrated to improve clinical outcomes. Previous trials showed the agreement between iFR and FFR is approximately 80%, however the details of discordance pattern remain to be elucidated.

METHODS

We retrospectively reviewed 1024 consecutive intermediate stenotic lesions for which functional evaluation using both iFR and FFR were performed between January 2015 and June 2016. The lesions were classified into 4 groups according to iFR and FFR concordance [(iFR+/FFR+) and (iFR-/FFR-)] or discordance [(iFR+/FFR-) and (iFR-/FFR+)].

RESULTS

Our study evaluated 451 lesions, 264 lesions (58.5%) from men and 187 lesions (41.5%) from women. iFR was similar between women and men, however FFR was significantly higher in women than men. The rate of discordance between iFR and FFR was 21.3% (iFR+/FFR- 12.4% and iFR-/FFR+ 8.9%) in overall cohort. The prevalence of overall concordance and discordance were similar between men and women, however iFR+/FFR- discordance was significantly higher in women (17.1% vs. 9.1%) whereas iFR-/FFR+ discordance was significantly higher in men (11.3% vs. 4.8%). In multivariable analysis, female sex and older age were significantly associated with iFR+/FFR- discordance (odds ratio 1.88 and 1.48, respectively). Conversely, younger age, higher stenosis, and concomitant chronic total occlusion were independent predictors for iFR-/FFR+ discordance (odds ratio 0.67, 1.82, and 4.32, respectively).

CONCLUSIONS

Despite similar prevalence of overall concordance and discordance between men and women, iFR+/FFR- discordance was higher in women and iFR-/FFR+ discordance was higher in men. Multivariable analysis showed female sex to be independent predictor of iFR+/FFR- discordance.

Influence of Sex on Relationship Between Total Anatomical and Physiologic Disease Burdens and Their Prognostic Implications in Patients With Coronary Artery Disease

Background Total atherosclerosis disease burden is associated with clinical outcomes in patients with coronary artery disease. However, the influence of sex on the relationship between total anatomical and physiologic disease burdens and their prognostic implications have not been well defined. Methods and Results A total of 1136 patients who underwent fractional flow reserve (FFR) measurement in all 3 major coronary arteries were included in this study. Anatomical and physiologic total disease burden was assessed by SYNTAX (Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery) score, residual SYNTAX score, a total sum of FFR in 3 vessels (3-vessel FFR), and functional SYNTAX score. The primary end point was major adverse cardiac events, a composite of cardiac death, myocardial infarction, and ischemia-driven revascularization at 2 years. There were no differences in angiographic diameter stenosis, SYNTAX score, or residual SYNTAX score between women and men. However, both per-vessel FFR (0.89±0.10 versus 0.87±0.11, P<0.001) and 3-vessel FFR (2.72±0.13 versus 2.69±0.15, P<0.001) were higher in women. Multivariable Cox regression analyses showed that total anatomical and physiologic disease burdens were significantly associated with 2-year major adverse cardiac events, and there was no significant interaction between sex and total disease burden for clinical outcomes. Conclusions Despite similar angiographic disease severity, both per-vessel and per-patient physiologic disease severity was less in women than in men. There was no influence of sex on prognostic implications of total anatomical and physiologic disease burdens in patients with coronary artery disease. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT01621438.

Impact of Sex Difference on the Discordance of Revascularization Decision Making Between Fractional Flow Reserve and Diastolic Pressure Ratio During the Wave-Free Period

Background

Sex difference in fractional flow reserve (FFR) and resting index has not been fully clarified. We sought to investigate the impact of sex on the discordance of revascularization decision making between FFR and diastolic pressure ratio during the diastolic wave‐free period (dPR_WFP).

Methods and Results

A total of 759 angiographically intermediate lesions with 30% to 80% diameter stenosis by quantitative coronary angiography in 577 patients in whom FFR and dPR_WFP were measured were investigated. dPR_WFP was measured during the wave‐free window of 5 heart cycles at an independent core laboratory. FFR ≤0.80 and dPR_WFP ≤0.89 were considered positive studies. A total of 164 vessels in 126 women (21.6%) and 595 vessels in 451 men (78.4%) were included. In lesions with negative dPR_WFP, positive FFR was less frequently observed in women (13 of 73; 17.8%) than in men (97 of 286; 33.9%) (P=0.009). In lesions with positive dPR_WFP, the frequency of negative FFR was observed in 22 of 91 vessels (24.2%) in women and 51 of 309 vessels (16.5%) in men, which did not reach statistical significance (P=0.098). In multivariable analyses, female sex was independently associated with FFR‐dPR_WFP discordance both in negative dPR_WFP cohort (odds ratio, 0.44; 95% CI, 0.21–0.98; P=0.036) and in positive dPR_WFP cohort (odds ratio, 2.41; 95% CI, 1.17–4.96; P=0.017) after adjustment for age, weight, quantitative coronary angiography data, and baseline physiological indexes.

Conclusions

The frequency of FFR‐dPR_WFP discordance was significantly associated with sex, which may indicate potential shift of optimal threshold of either FFR or dPR_WFP, or both of them, according to sex.

Sex Differences in Long-Term Outcomes in Patients With Deferred Revascularization Following Fractional Flow Reserve Assessment: International Collaboration Registry of Comprehensive Physiologic Evaluation

Background

Sex‐specific differences may influence prognosis after deferred revascularization following fractional flow reserve (FFR) measurement. This study sought to investigate the sex differences in long‐term prognosis of patients with deferred revascularization following FFR assessment.

Methods and Results

A total of 879 patients (879 vessels) with deferred revascularization with FFR >0.75 who underwent FFR and coronary flow reserve measurements were enrolled from 3 countries (Korea, Japan, and Spain). Long‐term outcomes were assessed in 649 men and 230 women by the patient‐oriented composite outcome (POCO, a composite of any death, any myocardial infarction, and any revascularization). We applied inverse‐probability weighting based on propensity scores to account for differences at baseline between women and men (age, hyperlipidemia, diabetes mellitus, diameter stenosis, lesion length, multivessel disease, FFR, coronary flow reserve. The median follow‐up duration was 1855 days (745–1855 days). Median FFR values were 0.88 (0.83–0.93) in men and 0.89 (0.85–0.94) in women, respectively. The occurrences of POCO were significantly high in men compared with that in women (10.5% versus 4.2%, P=0.007). Kaplan–Meier analysis revealed that women had a significantly lower risk of POCO (χ²=7.2, P=0.007). Multivariate COX proportional hazards regression analysis revealed that age, male, diabetes mellitus, diameter stenosis, lesion length, and coronary flow reserve were independent predictors of POCO. After applying IPW, the hazard ratio of males for POCO was 2.07 (95% CI, 1.07–4.04, P=0.032).

Conclusions

This large multinational study reveals that long‐term outcome differs between women and men in favor of women after FFR‐guided revascularization deferral.

Clinical Trial Registration

URL: http://www.ClinicalTrials.gov. Unique identifier: NCT02186093.

Fractional Flow Reserve Evaluated as Metric of Coronary Stenosis - A Mathematical Model Study

Introduction: Coronary arterial stenosis may impair myocardial perfusion with myocardial ischemia and associated morbidity and mortality as result. The myocardial fractional flow reserve (FFR) is clinically used as a stenosis-specific index. Aim: This study aims to identify the relation between the FFR and the degree of coronary arterial stenosis using a simple mathematical model of the coronary circulation. Methods: A mathematical model of the coronary circulation, including an arterial stenosis of variable degree, was developed. The relation between the FFR and the degree of stenosis (defined as the fractional cross sectional area narrowing) was investigated, including the influence of the aortic and venous pressures and the capillary resistance. An additional study concerning 22 patients with coronary artery disease permits comparison of clinical data and in silico findings. Results: The FFR shows an S-shaped relationship with the stenosis index. We found a marked influence of venous and aortic pressure and capillary resistance. The FFR is accompanied by a clinically relevant co-metric (FFR C ), defined by the Pythagorean sum of the two pressures in the definition formula for FFR. In the patient group the FFR C is strongly related to the post-stenotic pressure (R = 0.91). The FFR C requires establishment of a validated cut-off point using future trials. Conclusion: The S-shaped dependence of FFR on the severity of the stenosis makes the FFR a measure of the ordinal scale. The marked influences of the aortic and venous pressures and the capillary resistance on the FFR will be interpreted as significant variations in intra- and inter-individual clinical findings. These fluctuations are partly connected to the neglect of considering the FFR C . At otherwise identical conditions the FFR as measured at baseline differs from the value obtained during hyperemic conditions. This expected observation requires further investigation, as the current hyperemia based evaluation fails to take advantage of available baseline data.

Impact of Subtended Myocardial Mass Assessed by Coronary Computed Tomographic Angiography-Based Myocardial Segmentation

Although decision-making for revascularization is based on the extent of ischemic myocardium, the prognostic implication of supplying myocardial territories has not yet been studied. To evaluate the clinical impact of the coronary artery-based myocardial segmentation (CAMS)-derived myocardial volume subtended to the poststenotic segment, and to determine clinically relevant coronary lesions, coronary computed tomography angiography, invasive coronary angiography, and preprocedure fractional flow reserve (FFR) data were analyzed in 664 deferred lesions (in 577 patients) and 401 treated lesions (in 369 patients) with drug-eluting stent implantation, respectively. Using CAMS method, the myocardial volume subtended to a stenotic coronary segment (V_sub) was assessed. The primary composites included target vessel-related major adverse cardiac event (MACE) including cardiac death, myocardial infarction, and target vessel revascularization over 3 years. Independent predictors of 3-year MACE in deferred lesions were V_sub (adjusted hazard ratio [HR] 1.02), FFR (adjusted HR per 0.1 = 0.60), and distal reference luminal diameter (adjusted HR 2.04, all p < 0.05). A V_sub ≥ 36.2cc was predictive of MACE in deferred lesions with a sensitivity 72% and a specificity 67% (area under curve 0.71, 95% confidence interval 0.67 to 0.74, p < 0.001). V_sub was not associated with target vessel-related MACE. For the prediction of FFR < 0.80, the area under curve of V_sub/MLD⁴ > 6.3 was greater than those of angiographic diameter stenosis (0.78 vs 0.69) and minimal luminal diameter (0.78 vs 0.71), (all p < 0.05). CAMS-derived V_sub predicted 3-year clinical outcomes in untreated coronary lesions, and improved the diagnostic performance of angiography-derived parameters to identify ischemia-producing lesions.

Percutaneous coronary and structural interventions in women: a position statement from the EAPCI Women Committee

Several expert documents on sex-based differences in interventional outcomes are now available, however this is the first position paper from the EAPCI Women Committee discussing the potential influence of sex in the percutaneous treatment of coronary and structural heart disease. Despite the misconception that coronary artery disease is a 'man's disease', contemporary data shows a growing incidence in women. However, women are under-represented in randomised coronary clinical trials (~25%). The generalisation of such studies is therefore problematic in decision-making for females undergoing coronary intervention. Differences in pathophysiology between sexes exist, highlighting the need for greater awareness amongst healthcare professionals to enable best evidence-based therapies for women as well as for men. Reassuringly, women represent half of the population included in transcatheter aortic valve implantation clinical trials and may actually benefit more. Growing evidence is also emerging for other interventional atrial procedures which may well be advantageous to women. Awareness of sex disparities is increasing, and we must all work collaboratively within our profession to ensure we provide effective care for all patients with heart disease. The EAPCI Women Committee aim to highlight such issues through this position paper and through visibility within the interventional community.

Sex Differences in Adenosine-Free Coronary Pressure Indexes: A CONTRAST Substudy

OBJECTIVES

The goal of this study was to investigate sex differences in adenosine-free coronary pressure indexes.

BACKGROUND

Several adenosine-free coronary pressure wire indexes have been proposed to assess the functional significance of coronary artery lesions; however, there is a theoretical concern that sex differences may affect diagnostic performance because of differences in resting flow and distal myocardial mass.

METHODS

In this CONTRAST (Can Contrast Injection Better Approximate FFR Compared to Pure Resting Physiology?) substudy, contrast fractional flow reserve (cFFR), obtained during contrast-induced submaximal hyperemia, the instantaneous wave-free ratio (iFR), and distal/proximal coronary pressure ratio (Pd/Pa) were compared with fractional flow reserve (FFR) in 547 men and 216 women. Using FFR ≤0.8 as a reference, the diagnostic performance of each index was compared.

RESULTS

Men and women had similar diameter stenosis (p = 0.78), but women were less likely to have FFR ≤0.80 than men (42.5% vs. 51.5%, p = 0.04). Sensitivity was similar among cFFR, iFR, and Pd/Pa when comparing women and men, respectively (cFFR, 77.5% vs. 75.3%; p = 0.69; iFR, 84.9% vs. 79.4%; p = 0.30; Pd/Pa, 78.8% vs. 77.3%; p = 0.78). cFFR was more specific than iFR or Pd/Pa regardless of sex (cFFR, 94.3% vs. 95.8%; p = 0.56; iFR, 75.6% vs. 80.1%; p = 0.38; Pd/Pa, 80.6% vs. 78.7%; p = 0.69). By receiver-operating characteristic curve analysis, cFFR provided better diagnostic accuracy than resting indexes irrespective of sex (p ≤ 0.0001).

CONCLUSIONS

Despite the theoretical concern, the diagnostic sensitivity and specificity of cFFR, iFR, and Pd/Pa did not differ between the sexes. Irrespective of sex, cFFR provides the best diagnostic performance.

Unsettled Issues and Future Directions for Research on Cardiovascular Diseases in Women

Biological sex (being female or male) significantly influences the course of disease. This simple fact must be considered in all cardiovascular diagnosis and therapy. However, major gaps in knowledge about and awareness of cardiovascular disease in women still impede the implementation of sex-specific strategies. Among the gaps are a lack of understanding of the pathophysiology of women-biased coronary artery disease syndromes (spasms, dissections, Takotsubo syndrome), sex differences in cardiomyopathies and heart failure, a higher prevalence of cardiomyopathies with sarcomeric mutations in men, a higher prevalence of heart failure with preserved ejection fraction in women, and sex-specific disease mechanisms, as well as sex differences in sudden cardiac arrest and long QT syndrome. Basic research strategies must do more to include female-specific aspects of disease such as the genetic imbalance of 2 versus one X chromosome and the effects of sex hormones. Drug therapy in women also needs more attention. Furthermore, pregnancy-associated cardiovascular disease must be considered a potential risk factor in women, including pregnancy-related coronary artery dissection, preeclampsia, and peripartum cardiomyopathy. Finally, the sociocultural dimension of gender should be included in research efforts. The organization of gender medicine must be established as a cross-sectional discipline but also as a centered structure with its own research resources, methods, and questions.

Assessing Coronary Blood Flow Physiology in the Cardiac Catheterisation Laboratory

Background:

Contemporary management of coronary disease focuses on the treatment of stenoses in the major epicardial vessels. However, myocardial blood flow is known to be contingent on a range of factors in addition to the patency of the epicardial vessels. These include anatomical and physiological factors such as the extent of myocardium supplied by the vessel, systemic blood pres-sure, the natural variation in vascular tone in response to physiological needs which allows for coro-nary autoregulation and pathological factors such as the presence of downstream obstruction to flow due to disease of the small coronary vessels or myocardium. The assessment of clinical effectiveness and adequacy of coronary revascularisation requires the ability to comprehensively and accurately as-sess and measure myocardial perfusion.

Conclusion:

In this article, we review the current methods of evaluating coronary blood flow and my-ocardial perfusion in the cardiac catheterisation laboratory.

Fractional flow reserve and resting indices for coronary physiologic assessment: Practical guide, tips, and tricks

Physiologic assessment using fractional flow reserve (FFR) to guide percutaneous coronary interventions (PCI) has been demonstrated to improve clinical outcomes, compared to angiography-guided PCI. Recently, resting indices such as resting Pd/Pa, "instantaneous wave-free ratio", and contrast medium induced FFR have been evaluated for the assessment of the functional consequences of coronary lesions. Herein, we review and discuss the use of FFR and other indices for the functional assessment of coronary lesions. This review will cover theoretical aspects, as well as practical points and common pitfalls related to coronary physiological assessment. © 2017 Wiley Periodicals, Inc.

Clinical Outcomes of Deferred Lesions With Angiographically Insignificant Stenosis But Low Fractional Flow Reserve

Background

Data are limited regarding outcomes of deferred lesions in patients with angiographically insignificant stenosis but low fractional flow reserve (FFR). We investigated the natural history of angiographically insignificant stenosis with low FFR among patients who underwent routine 3‐vessel FFR measurement.

Methods and Results

From December 2011 to March 2014, 1136 patients with 3298 vessels underwent routine 3‐vessel FFR measurement (3V FFR‐FRIENDS study, ClinicalTrials.gov identifier NCT01621438), and this study analyzed the 2‐year clinical outcomes of 1024 patients with 2124 lesions with angiographically insignificant stenosis (percentage of diameter stenosis <50%), in which revascularization was deferred. All lesions were classified according to FFR values, using a cutoff of 0.80 (high FFR >0.80 versus low FFR ≤0.80). The primary end point was outcome of major adverse cardiovascular events (a composite of cardiac death, myocardial infarction, and ischemia‐driven revascularization) at 2 years. Mean angiographic percentage of diameter stenosis and FFR of total lesions were 32.5±10.3% and 0.91±0.08%, respectively. Among the total lesions with angiographically insignificant stenosis, 8.7% showed low FFR (185 lesions). The incidence of lesions with low FFR was 2.5%, 3.8%, 9.0%, and 15.1% in categories of percentage of diameter stenosis <20%, 20% to 30%, 30% to 40%, and 40% to 50%, respectively. At 2‐year follow‐up, the low‐FFR group showed a significantly higher risk of major adverse cardiovascular events compared with the high FFR group (3.3% versus 1.2%, hazard ratio: 3.371; 95% CI, 1.346–8.442; P=0.009). In multivariable analysis, low FFR was the most powerful independent predictor of future MACE in deferred lesions with angiographically insignificant stenosis (adjusted hazard ratio: 2.617; 95% CI, 1.026–6.679; P=0.044).

Conclusions

In deferred angiographically insignificant stenosis, lesions with low FFR showed significantly higher event rates than those with high FFR. FFR was an independent predictor of future major adverse cardiovascular events in lesions with angiographically insignificant stenosis.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01621438.

Fractional flow reserve: a clinical perspective

Fractional flow reserve (FFR) is a reference invasive diagnostic test to assess the physiological significance of an epicardial coronary artery stenosis. FFR-guided percutaneous coronary intervention in stable coronary artery disease has been assessed in three seminal clinical trials and the indications for FFR assessment are expanding into other clinical scenarios. In this article we review the theoretical, experimental and clinical basis for FFR measurement. We place FFR measurement in the context of the comprehensive invasive assessment of coronary physiology in patients presenting with known or suspected angina pectoris in daily clinical practice, and review the recent developments in FFR assessment.

Integrated Myocardial Perfusion Imaging Diagnostics Improve Detection of Functionally Significant Coronary Artery Stenosis by 13 N-ammonia Positron Emission Tomography

Background—

Recent evidence suggests that the diagnostic accuracy of myocardial perfusion imaging is improved by quantifying stress myocardial blood flow (MBF) in absolute terms. We evaluated a comprehensive quantitative 13 N-ammonia positron emission tomography ( 13 NH 3 -PET) diagnostic panel, including stress MBF, coronary flow reserve (CFR), and relative flow reserve (RFR) in conjunction with relative perfusion defect (PD) assessments to better detect functionally significant coronary artery stenosis.

Methods and Results—

A total of 130 patients (307 vessels) with coronary artery disease underwent both 13 NH 3 -PET and invasive coronary angiography with fractional flow reserve (FFR) measurement. Diagnostic accuracy, optimal cut points, and discrimination indices of respective 13 NH 3 -PET quantitative measures were compared, with FFR as standard reference. The capacity to discern disease with stepwise addition of stress MBF, CFR, and RFR to qualitatively assessed relative PD was also gauged, using the category-free net reclassification index. All quantitative measures showed significant correlation with FFR (PET-derived CFR, r =0.388; stress MBF, r =0.496; and RFR, r =0.780; all P <0.001). Optimal respective cut points for FFR ≤0.8 and ≤0.75 were 1.99 and 1.84 mL/min per g for stress MBF and 2.12 and 2.00 for PET-derived CFR. Discrimination indices of quantitative measures that correlated with FFR ≤0.8 were all significantly higher than that of relative PD (area under the curve: 0.626, 0.730, 0.806, and 0.897 for relative PD, CFR, stress MBF, and RFR, respectively; overall comparison P <0.001). The capacity for functionally significant coronary stenosis was incrementally improved by the successive addition of CFR (net reclassification index=0.629), stress MBF (net reclassification index=0.950), and RFR (net reclassification index=1.253; all P <0.001) to relative PD.

Conclusions—

Integrating quantitative 13 NH 3 -PET measures with qualitative myocardial perfusion assessment provides superior diagnostic accuracy and improves the capacity to detect functionally significant coronary artery stenosis.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifiers: NCT01621438 and NCT01366404.

When should fractional flow reserve be performed to assess the significance of borderline coronary artery lesions: Derivation of a simplified scoring system

OBJECTIVES

To derive a simplified scoring system (SSS) that can assist in selecting patients who would benefit from the application of fractional flow reserve (FFR).

BACKGROUND

Angiographers base decisions to perform FFR on their interpretation of % diameter stenosis (DS), which is subject to variability. Recent studies have shown that the amount of myocardium at jeopardy is an important factor in determining the degree of hemodynamic compromise.

METHODS

We conducted a retrospective multivariable analysis to identify independent predictors of hemodynamic compromise in 289 patients with 317 coronary vessels undergoing FFR. A SSS was derived using the odds ratios as a weighted factor. The receiver operator characteristics curve was used to identify the optimal cutoff (≥3) to discern a functionally significant lesion (FFR≤0.8).

RESULTS

Male gender, left anterior descending artery apical wrap, disease proximal to lesion, minimal lumen diameter and % DS predicted abnormal FFR (≤0.8) and lesion location in the left circumflex predicted a normal FFR. Using a cutoff score of ≥3 on the SSS, a specificity of 90.4% (95% CI: 83.0-95.3) and a sensitivity of 38.0% (95% CI: 31.5-44.9) was generated with a positive predictive value of 89.0% (95% CI: 80.7%-94.6%) and negative predictive value of 41.6% (95% CI: 35.1%-48.3%).

CONCLUSIONS

The decision to use FFR should be based not only on the % DS but also the size of the myocardial mass jeopardized. A score of ≥3 on the SSS should prompt further investigation with a pressure wire.

Mathematically Derived Criteria for Detecting Functionally Significant Stenoses Using Coronary Computed Tomographic Angiography-Based Myocardial Segmentation and Intravascular Ultrasound-Measured Minimal Lumen Area

The lack of practical method for quantifying myocardial territories has made it difficult to link anatomic lesion morphology to the hemodynamic significance of coronary artery stenosis. The aim of this study was to develop and validate mathematically derived morphologic criteria for predicting fractional flow reserve (FFR) <0.80 using intravascular ultrasound (IVUS) parameters and a coronary artery-based myocardial segmentation (CAMS) of the affected myocardial territory. Coronary computed tomography angiography, IVUS, and FFR data were analyzed in 103 non-left main intermediate coronary artery lesions (30% to 80% of angiographic stenosis). Using CAMS method, the total left ventricular myocardial volume and the myocardial volume subtended by a stenotic coronary segment (Vsub) were assessed. The morphologic criteria for detecting an FFR <0.80 using the IVUS and CAMS parameters were mathematically derived. Overall, an IVUS-measured minimal lumen area (MLA) <2.79 mm(2) predicted an FFR <0.80 with sensitivity of 76%, specificity of 78%, positive predictive value of 71%, and negative predictive value of 82%. A Vsub/MLA(2) >4.04 best predicted an FFR <0.80 (sensitivity 88%, specificity 90%, positive predictive value 86%, and negative predictive value 92%, area under curve = 0.944). There was a significant difference in the areas under the curves between IVUS-MLA versus Vsub/MLA(2) (difference = 0.068, p = 0.005). Conversely, adjusting for body or vessel size did not improve the diagnostic accuracy.

Factors Associated With Errors in Visual Estimation of the Functional Significance of Coronary Lesions

INTRODUCTION AND 

OBJECTIVES

Visual angiographic assessment continues to be used when decisions are made on whether to revascularize ambiguous coronary lesions. Multiple factors, other than the degree of stenosis, have been associated with the functional significance of a coronary lesion. The aim of this study was to investigate the ability of interventionists to visually predict the functional significance of a coronary lesion and the clinical and angiographic characteristics associated with errors in prediction.

METHODS

We conducted a concordance study of the functional significance of coronary lesions predicted by experienced interventionists and fractional flow reserve values measured by intracoronary pressure wire in 665 intermediate lesions (40%-70% diameter stenosis) in 587 patients. We determined which factors were independently associated with errors in prediction.

RESULTS

There was disagreement between the predicted fractional flow reserve value of ≤ 0.80 and the observed value in 30.1% of the lesions (overestimation: 11.3%; underestimation, 18.8%). Stent location in an artery other than the anterior descending artery or in a bifurcation was associated with overestimation. Male sex, severe calcification, and a greater myocardial territory distal to the lesion were significantly associated with the functional significance of the underestimated lesion.

CONCLUSIONS

Even when taking into account angiographic and clinical characteristics, there is a high rate of disagreement between visual estimation and direct measurement of intermediate coronary stenosis in relation to its functional significance. Specific angiographic and clinical characteristics are associated with an increased tendency to overestimate or underestimate the significance of lesions.

Better Diagnosis of Functionally Significant Intermediate Sized Narrowings Using Intravascular Ultrasound-Minimal Lumen Area and Coronary Computed Tomographic Angiography-Based Myocardial Segmentation

Lesion morphology poorly predicts functional significance of intermediate coronary artery stenosis. The aim of this study was to determine whether a coronary artery-based myocardial segmentation method that quantifies subtended myocardium can improve the diagnostic accuracy of intravascular ultrasound (IVUS)-derived parameters for detecting ischemia-producing lesions. Coronary computed tomography angiography, IVUS, and fractional flow reserve (FFR) data were analyzed in 101 non-left main lesions (20% to 80% angiographic stenosis). Using the coronary artery-based myocardial segmentation method, total left ventricular myocardial volume (Vtotal), myocardial volume subtended by the stenotic coronary segment (Vsub), and Vratio (the ratio of the Vsub to the Vtotal) were assessed. Both Vsub >30.7 cm(3) and Vratio >25.4% were determinants of FFR ≤0.75 (area under the curve = 0.696 and 0.744). Overall, an IVUS-measured minimum lumen area (IVUS-MLA) ≤2.83 mm(2) predicted FFR ≤0.75 with a sensitivity 88% and specificity 73%. Among lesions with IVUS-MLA ≤2.83 mm(2) and FFR >0.75, 89% showed Vsub <30.7 cm(3). In 50 lesions with Vsub >30.7 cm(3), an IVUS-MLA ≤2.85 mm(2) predicted FFR ≤0.75 with sensitivity 85%, specificity 92%, positive predictive value 92%, and negative predictive value 85%. Conversely, in 51 lesions with a Vsub ≤30.7 cm(3), IVUS-MLA ≤2.67 mm(2) showed sensitivity 100%, specificity 69%, positive predictive value 38%, and negative predictive value 100% for predicting FFR ≤0.75. Body surface area, reference lumen diameter, and vessel area had modest correlations with Vsub. In those lesion subsets, IVUS-MLA ≈2.8 mm(2) accurately predicted an FFR ≤0.75, whereas the clinical relevance of assessing and treating lesions with a smaller myocardial territory may be limited (ClinicalTrials.gov number NCT1696006).