Very late vasomotor responses and gene expression with bioresorbable scaffolds and metallic drug-eluting stents.

OBJECTIVES: To investigate the long-term vasomotor response and inflammatory changes in Absorb bioresorbable vascular scaffold (BVS) and metallic drug-eluting stent (DES) implanted artery. BACKGROUND: Clinical evidence has demonstrated that compared to DES, BVS is associated with higher rates of target lesion failure. However, it is not known whether the higher event rates observed with BVS are related to endothelial dysfunction or inflammation associated with polymer degradation. METHODS: Ten Absorb BVS and six Xience V DES were randomly implanted in the main coronaries of six nonatherosclerotic swine. At 4-years, vasomotor response was evaluated in vivo by quantitative coronary angiography response to intracoronary infusion of Ach and ex vivo by the biomechanical response to prostaglandin F2-α (PGF2-α), substance P and bradykinin and gene expression analysis. RESULTS: Absorb BVS implanted arteries showed significantly restored vasoconstrictive responses after Ach compared to in-stent Xience V. The contractility of Absorb BVS treated segments induced by PGF2-α was significantly greater compared to Xience V treated segments and endothelial-dependent vasorelaxation was greater with Absorb BVS compared to Xience V. Gene expression analyses indicated the pro-inflammatory lymphotoxin-beta receptor (LTßR) signaling pathway was significantly upregulated in arteries treated with a metallic stent compared to Absorb BVS treated arterial segments. CONCLUSIONS: At 4 years, arteries treated with Absorb BVS compared with Xience V, demonstrate significantly greater restoration of vasomotor responses. Genetic analysis suggests mechanobiologic reparation of Absorb BVS treated arteries at 4 years as opposed to Xience V treated vessels.

Efficacy and safety of drug-eluting stents in elderly patients: A meta-analysis of randomized trials.

BACKGROUND: Current guidelines recommend newer generation drug-eluting stents (DES) over bare-metal stents (BMS) in patients with ischemic heart disease. However, there is no age-specific recommendation in elderly patients. METHODS: Meta-analysis was performed of 6 randomized studies enrolling 5,042 elderly patients who underwent percutaneous coronary intervention (PCI) with stent implantation (DES, n = 2,579; BMS, n = 2,463). RESULTS: Combined data indicated a significant reduction in major adverse cardiovascular events (MACEs) with use of DES (odds ratio [OR] 0.56, 95% confidence interval [CI] 0.44-0.71, p < 0.001). Moreover, use of DES was associated with a significantly lower incidence of myocardial infarction (OR 0.54, 95% CI 0.36-0.81, p = 0.003) and repeat revascularization (OR 0.44, 95% CI 0.31-0.62, p < 0.001), was compared to that with the use of BMS. Stent thrombosis and bleeding complication rates were not significantly different between groups. In a subgroup meta-analysis, short duration (1 or 6 months) dual antiplatelet therapy (DAPT) was associated with a significantly lower MACE rate (OR 0.49, 95% CI 0.34-0.80; p = 0.003) in elderly patients who underwent PCI with everolimuseluting stent implantation, compared with that using long duration DAPT. CONCLUSIONS: This meta-analysis provides clinically relevant evidence that DES rather than BMS should be selected for elderly patients.

Overlapping Drug-Eluting Stent Is Associated with Increased Definite Stent Thrombosis and Revascularization: Results from 15,561 Patients in the AUTHENTIC Study.

PURPOSE: This study was to analyze the incidence of definite stent thrombosis (ST) after the implantation of drug-eluting stents (DESs) and cutoff value of overlapping length for predicting definite ST. An overlapping stent is associated with a high rate of clinical events after DES implantation compared with a non-overlapping stent. However, the rates of definite ST and clinical outcomes from a large patient population remain underreported. METHODS: A total of 15,561 patients with 24,183 lesions who underwent DES implantation from January 2005 to February 2017 were retrospectively included in 5 tertiary hospitals in China. The main endpoint was the incidence of definite ST after procedures. RESULTS: With a median of 1932 (IQR = 1194-2929) days, clinical follow-up was available in 7484 patients in the overlap group and in 8077 patients in the non-overlap group. The rates of definite ST were 3.1% in the overlap group and 1.2% in the non-overlap group (HR: 2.67 (95% CI: 2.11-3.38), p < 0.001). Of the 24,183 treated lesions, the incidences of definite ST were 2.4% in the overlap group and 0.9% in the non-overlap group (HR: 2.96 (95% CI: 2.38-3.69), p < 0.001). Stent overlap was associated with a higher rate of target lesion revascularization (TLR) (9.4%) compared with stent non-overlap (6.4%, p < 0.001). The length of overlapping stent ≥ 2.93 mm strongly correlated with definite ST. CONCLUSION: The present study shows that overlapping DES increases definite ST and revascularization in patients during long-term follow-up. In addition, the longer overlapping zone was associated with worse clinical outcomes.

The association of diabetes mellitus with neointimal formation following deployment of second-generation drug-eluting stents: an optical coherence tomographic study.

OBJECTIVES: The purpose of this study was to evaluate the association of diabetes mellitus (DM) with neointimal formation after implantation of second-generation drug-eluting stent (DES) visualized by optical coherence tomography (OCT). METHODS: Patients with single de novo coronary artery disease treated with second-generation DES between June 2014 and June 2017 in our department underwent OCT examination at 1-year follow-up and were enrolled in this retrospective study. The primary end point was in-stent mean neointimal thickness (MNT), and secondary end points included uncovered stent strut, minimal lumen area (MLA), neointimal burden, neointimal hyperplasia (NIH) patterns and stent thrombosis (ST) after 1 year of OCT follow-up. RESULTS: A total of 68 patents with DM (DM group) and 216 patients without DM (non-DM group) were enrolled. At 1-year follow-up, the DM group compared with the non-DM group, showed: MNT [160 (85-245) µm vs. 120 (60-220) µm, P = 0.038] and neointimal burden [21.4 (8.3-30.1)% vs. 14.0 (5.7-26.1)%, P = 0.023] to be significantly increased. Concurrently, MLA [4.60 (3.53-6.06) mm vs. 5.76 (4.28-7.20) mm2, P = 0. 0.002] was significantly reduced. Interestingly, the degree of uncovered struts (7.3 ± 7.1% vs. 7.7 ± 6.7%, P = 0.704), NIH patterns (P = 0.984), and ST (7.9% vs. 7.4%, P = 0.88) were comparable between the two groups. After propensity score matching, the MNT [160 (90-240) µm vs. 110 (60-220) µm, P = 0.048] and neointimal burden [21.4 (8.3-30.1)% vs. 15.4 (5.6-26.3)%, P = 0.044] remained significantly different in the DM compared to the non-DM group. CONCLUSION: DM leads to significant increase in MNT and neointimal burden even with second-generation DES, nevertheless stent strut coverage, ST and NIH characteristics remained comparable among the cohorts at 1-year.

Trends of repeat revascularization choice in patients with prior coronary artery bypass surgery.

OBJECTIVE: To examine rates and predictors repeat revascularization strategies (percutaneous coronary intervention [PCI] and coronary artery bypass grafting [CABG]) in patients with prior CABG. METHODS: Using the National Inpatient Sample, patients with a history of CABG hospitalized for revascularization by PCI or CABG from January 2004 to September 2015 were included. Regression analyses were performed to examine predictors of receipt of either revascularization strategy as well as in-hospital outcomes. RESULTS: The rate of redo CABG doubled between 2004 (5.3%) and 2015 (10.3%). Patients who underwent redo CABG were more comorbid and experienced significantly worse major adverse cardiovascular and cerebrovascular events (odds ratio [OR]: 5.36 95% CI 5.11-5.61), mortality (OR 2.84 95% CI 2.60,-3.11), bleeding (OR 5.97 95% CI 5.44-6.55) and stroke (OR 2.15 95% CI 1.92-2.41), but there was no difference in cardiac complications between groups. Thoracic complications were high in patients undergoing redo CABG (8%), especially in females. Factors favoring receipt of redo CABG compared to PCI included male sex, age < 80 years, and absence of diabetes and renal failure. CONCLUSION: Reoperation in patients with prior CABG has doubled in the United States over a 12-year period. Patients undergoing redo CABG are more complex and associated with worse clinical outcomes than those receiving PCI.

Optical coherence tomography predictors of target vessel myocardial infarction after provisional stenting in patients with coronary bifurcation disease.

BACKGROUND: Provisional side branch (SB) stenting is correlated with target vessel myocardial infarction (TVMI) in patients with coronary bifurcation lesions. However, the mechanisms underlying this association remain unknown. OBJECTIVES: To determine the correlation between SB lesion length with vulnerable plaques and TVMI using optical coherence tomography (OCT). BACKGROUND: The correlation between SB lesion length with vulnerable plaques and TVMI is unknown. METHODS: A total of 405 patients with 405 bifurcation lesions who underwent preprocedure OCT imaging of both the main vessel (MV) and the SB were enrolled. Patients were divided into long SB lesion (SB lesion length ≥10 mm) and short SB lesion (SB lesion length <10 mm) groups according to quantitative coronary analysis; they were also stratified by the presence of vulnerable plaques identified by OCT. The primary endpoint was the occurrence of TVMI after provisional stenting at 1-year follow-up. RESULTS: In total, 178 (43.9%) patients had long SB lesions. Vulnerable plaques were predominantly localized in the MV and were more frequently in the long SB lesion group (42.7%) than in the short SB lesion group (24.2%, p < .001). At 1-year follow-up after provisional stenting, there were 31 (7.7%) TVMIs, with 21 (11.8%) in the long SB lesion group and 10 (4.4%) in the short SB lesion group (p = .009). Multivariate regression analysis showed that long SB lesion length (p = .011), absence of vulnerable plaques in the polygon of confluence (p = .001), and true coronary bifurcation lesions (p = .004) were the three independent factors of TVMI. CONCLUSIONS: The presence of long SB lesion with MV vulnerable plaques predicts the increased risk of TVMI after provisional stenting in patients with true coronary bifurcation lesions. Further studies are warranted to identify the best stenting techniques for coronary bifurcation lesions with long SB lesions.

One-year efficacy and safety of everolimus-eluting bioresorbable scaffolds in the setting of acute myocardial infarction.

BACKGROUND AND OBJECTIVES: This study sought to compare clinical outcomes between bioresorbable scaffolds (BRS) and durable polymer everolimus-eluting metallic stents (DP-EES) in patients with acute myocardial infarction (AMI) undergoing successful percutaneous coronary intervention (PCI). METHODS: From March 2016 to October 2017, 952 patients with AMI without cardiogenic shock undergoing successful PCI with BRS (n = 136) or DP-EES (n = 816) were enrolled from a multicenter, observational Korea Acute Myocardial Infarction Registry. RESULTS: In the crude population, there was no significant difference in the 1-year rate of device-oriented composite endpoint (DOCE) and device thrombosis between the BRS and DP-EES groups (2.2% vs. 4.8%, hazard ratio [HR] 0.43, 95% confidence interval [CI] 0.13-1.41, p = 0.163; 0.7% vs. 0.5%, HR 1.49, 95% CI 0.16-13.4, p = 0.719, respectively). BRS implantation was opted in younger patients (53.7 vs. 62.6 years, p < 0.001) with low-risk profiles, and intravascular image-guided PCI was more preferred in the BRS group (60.3% vs. 27.2%, p < 0.001). CONCLUSIONS: At 1-year follow-up, no differences in the rate of DOCE and device thrombosis were observed between patients with AMI treated with BRS and those treated with DP-EES. Our data suggest that imaging-guided BRS implantation in young patients with low risk profiles could be a reasonable strategy in the setting of AMI.

Left Main Coronary Interventions: A Practical Guide.

Coronary artery bypass surgery has been the accepted treatment for left main coronary artery disease for over 50 years. Balloon angioplasty was later used then abandoned because of deaths likely due to restenosis or thrombotic occlusion. However, rapid innovations in drug-eluting stent designs leading to more biocompatible thin strut platforms with optimal drug elution profiles and further advances in modern pharmacotherapy involving potent P2Y12 inhibitors combined with utilization of intracoronary imaging and physiologic assessment for procedural planning and optimization have transformed percutaneous interventions into successful alternatives to coronary artery bypass graft surgery (CABG) in selected LM anatomic territories. Herein, we provide an evidence-based practical guide on how to approach and perform LM percutaneous interventions (PCI).

Bioresorbable vascular scaffolds versus everolimus-eluting stents: a biomechanical analysis of the ABSORB III Imaging substudy.

AIMS: The Absorb bioresorbable vascular scaffold (BVS) has high rates of target lesion failure (TLF) at three years. Low wall shear stress (WSS) promotes several mechanisms related to device TLF. We investigated the impact of BVS compared to XIENCE V (XV) on coronary WSS after device deployment. METHODS AND RESULTS: In the prospective, randomised, controlled ABSORB III Imaging study (BVS [n=77] or XV [n=36]), computational fluid dynamics were performed on fused angiographic and intravascular ultrasound (IVUS) images of post-implanted vessels. Low WSS was defined as <1 Pa. There were no differences in demographics, clinical risks, angiographic reference vessel diameter or IVUS minimal lumen diameter between BVS and XV patients. A greater proportion of vessels treated with BVS compared to XV demonstrated low WSS across the whole device (BVS: 17/77 [22%] vs XV: 2/36 [6%], p<0.029). Compared to XV, BVS demonstrated lower median circumferential WSS (1.73 vs 2.21 Pa; p=0.036), outer curvature WSS (p=0.026), and inner curvature WSS (p=0.038). Similarly, BVS had lower proximal third WSS (p=0.024), middle third WSS (p=0.047) and distal third WSS (p=0.028) when compared to XV. In a univariable logistic regression analysis, patients who received BVS were 4.8 times more likely to demonstrate low WSS across the scaffold/stent when compared to XV patients. Importantly, in a multivariable linear regression model, hypertension (beta: 0.186, p=0.023), lower contrast frame count velocity (beta: -0.411, p<0.001), lower post-stent residual plaque burden (beta: -0.338, p<0.001), lower % underexpanded frames (beta: -0.170, p=0.033) and BVS deployment (beta: 0.251, p=0.002) remained independently associated with a greater percentage of stented coronary vessel areas exposed to low WSS. CONCLUSIONS: In this randomised controlled study, the Absorb BVS was 4.8 times more likely than the XV metallic stent to demonstrate low WSS. BVS implantation, lower blood velocity and lower residual post-stent plaque burden were independently associated with greater area of low WSS.

Volume brings value.

What the article teaches The article highlights the competency of high volume operators across institutions that despite moving to lower volume centers retain their good clinical outcomes. How it will impact practice Although current U.S. based guidelines suggest a volume of at least 50 PCIs annually for operators to retain clinical competency this estimate may be a poor index to guarantee optimal clinical outcomes. What new research/study would help answer the question New studies using a comprehensive definition to define an experienced operator from the Asia-Pacific-a geographic area that has pioneered in complex coronary interventions-need to elute on the threshold of adequate clinical competency stratified according to clinical complexity.

Low Coronary Wall Shear Stress Is Associated With Severe Endothelial Dysfunction in Patients With Nonobstructive Coronary Artery Disease.

OBJECTIVES: This study investigated the relationship between low wall shear stress (WSS) and severe endothelial dysfunction (EDFx). BACKGROUND: Local hemodynamic forces such as WSS play an important role in atherogenesis through their effect on endothelial cells. The study hypothesized that low WSS independently predicts severe EDFx in patients with coronary artery disease (CAD). METHODS: Forty-four patients with CAD underwent coronary angiography, fractional flow reserve, and endothelial function testing. Segments with >10% vasoconstriction after acetylcholine (Ach) infusion were defined as having severe EDFx. WSS, calculated using 3-dimensional angiography, velocity measurements, and computational fluid dynamics, was defined as low (<1 Pa), intermediate (1 to 2.5 Pa), or high (>2.5 Pa). RESULTS: Median age was 52 years, 73% were women. Mean fractional flow reserve was 0.94 ± 0.06. In 4,510 coronary segments, median WSS was 3.67 Pa. A total of 24% had severe EDFx. A higher proportion of segments with low WSS had severe EDFx (71%) compared with intermediate WSS (22%) or high WSS (23%) (p < 0.001). Segments with low WSS demonstrated greater vasoconstriction in response to Ach than did intermediate or high WSS segments (-10.7% vs. -2.5% vs. +1.3%, respectively; p < 0.001). In a multivariable logistic regression analysis, female sex (odds ratio [OR]: 2.44; p = 0.04), diabetes (OR: 5.01; p = 0.007), and low WSS (OR: 9.14; p < 0.001) were independent predictors of severe EDFx. CONCLUSIONS: In patients with nonobstructive CAD, segments with low WSS demonstrated more vasoconstriction in response to Ach than did intermediate or high WSS segments. Low WSS was independently associated with severe EDFx.

High Coronary Shear Stress in Patients With Coronary Artery Disease Predicts Myocardial Infarction.

BACKGROUND: Coronary lesions with low fractional flow reserve (FFR) that are treated medically are associated with higher revascularization rates. High wall shear stress (WSS) has been linked with increased plaque vulnerability. OBJECTIVES: This study investigated the prognostic value of WSS measured in the proximal segments of lesions (WSSprox) to predict myocardial infarction (MI) in patients with stable coronary artery disease (CAD) and hemodynamically significant lesions. The authors hypothesized that in patients with low FFR and stable CAD, higher WSSprox would predict MI. METHODS: Among 441 patients in the FAME II (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation II) trial with FFR ≤0.80 who were randomized to medical therapy alone, 34 (8%) had subsequent MI within 3 years. Patients with vessel-related MI and adequate angiograms for 3-dimensional reconstruction (n = 29) were propensity matched to a control group with no MI (n = 29) by using demographic and clinical variables. Coronary lesions were divided into proximal, middle, and distal, along with 5-mm upstream and downstream segments. WSS was calculated for each segment. RESULTS: Median age was 62 years, and 46 (79%) were male. In the marginal Cox model, whereas lower FFR showed a trend (hazard ratio: 0.084; p = 0.064), higher WSSprox (hazard ratio: 1.234; p = 0.002, C-index = 0.65) predicted MI. Adding WSSprox to FFR resulted in a significant increase in global chi-square for predicting MI (p = 0.045), a net reclassification improvement of 0.69 (p = 0.005), and an integrated discrimination index of 0.11 (p = 0.010). CONCLUSIONS: In patients with stable CAD and hemodynamically significant lesions, higher WSS in the proximal segments of atherosclerotic lesions is predictive of MI and has incremental prognostic value over FFR.

Intravascular Ultrasound Versus Angiography-Guided Drug-Eluting Stent Implantation: The ULTIMATE Trial.

BACKGROUND: Intravascular ultrasound (IVUS)-guided drug-eluting stent (DES) implantation is associated with fewer major adverse cardiovascular events compared with angiography guidance for patients with individual lesion subset. However, the beneficial effect on major adverse cardiovascular event outcome of IVUS guidance over angiography guidance in all-comers who undergo DES implantation still remains understudied. OBJECTIVES: This study aimed to determine the benefits of IVUS guidance over angiography guidance during DES implantation in all-comer patients. METHODS: A total of 1,448 all-comer patients who required DES implantation were randomly assigned (1:1 ratio) to either an IVUS guidance or angiography guidance group. The primary endpoint was target-vessel failure (TVF) at 12 months, including cardiac death, target-vessel myocardial infarction, and clinically driven target-vessel revascularization (TVR). The procedure was defined as a success if all IVUS-defined optimal criteria were met. RESULTS: At 12 months follow-up, 60 TVFs (4.2%) occurred, with 21 (2.9%) in the IVUS group and 39 (5.4%) in the angiography group (hazard ratio [HR]: 0.530; 95% confidence interval [CI]: 0.312 to 0.901; p = 0.019). In the IVUS group, TVF was recorded in 1.6% of patients with successful procedures, compared with 4.4% in patients who failed to achieve all optimal criteria (HR: 0.349; 95% CI: 0.135 to 0.898; p = 0.029). The significant reduction of clinically driven target-lesion revascularization or definite stent thrombosis (HR: 0.407; 95% CI: 0.188 to 0.880; p = 0.018) based on lesion-level analysis by IVUS guidance was not achieved when the patient-level analysis was performed. CONCLUSIONS: The present study demonstrates that IVUS-guided DES implantation significantly improved clinical outcome in all-comers, particularly for patients who had an IVUS-defined optimal procedure, compared with angiography guidance. (Intravascular Ultrasound Guided Drug Eluting Stents Implantation in "All-Comers" Coronary Lesions [ULTIMATE]; NCT02215915).

Performance of J-CTO and PROGRESS CTO Scores in Predicting Angiographic Success and Long-term Outcomes of Percutaneous Coronary Interventions for Chronic Total Occlusions.

Patient selection for and predicting clinical outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) remain challenging. We hypothesized that both J-CTO (Multicenter Chronic Total Occlusion Registry of Japan) and PROGRESS CTO (Prospective Global Registry for the Study of Chronic Total Occlusion Intervention) scores will predict not only angiographic success but also long-term clinical outcomes of the patients who underwent PCI of CTO. Of 325 CTO PCIs performed at 2 Emory University hospitals from January 2012 to August 2015, 249 patients with complete baseline clinical, angiographic and follow-up data, were included in this analysis. Major adverse cardiovascular events (MACEs) consisted of a composite of death, myocardial infarction, and target vessel revascularization. Mean age was 63 ± 11 years old and mean follow-up was 19.8 ± 13.1 months. Angiographic success rates increased from 74.5% in 2012 to 85.7% in 2015. Greater J-CTO and PROGRESS CTO scores were not only associated with lower likelihood of angiographic success but also higher rates of long-term MACE. Compared with the scores of 0 to 2, J-CTO and PROGRESS CTO scores of ≥3 were associated with higher MACE. Multivariable analysis demonstrated that PROGRESS CTO scores of ≥3, male sex, and peripheral vascular disease were independent predictors of MACE. In conclusion, J-CTO and PROGRESS CTO scores are useful in predicting procedural success. In addition, the PROGRESS CTO score, and to a lesser degree J-CTO score, have predictive value for long-term outcomes in patients who underwent CTO PCI.

Long-term safety of bioresorbable scaffolds: insights from a network meta-analysis including 91 trials.

AIMS: The aim of this study was to investigate the long-term safety and efficacy of biodegradable scaffolds and metallic stents. METHODS AND RESULTS: We analysed a total of 91 randomised controlled trials with a mean follow-up of 3.7 years in 105,842 patients which compared two or more coronary metallic stents or biodegradable scaffolds and reported the long-term clinical outcomes (≥2 years). Network meta-analysis showed that patients treated with the Absorb bioresorbable vascular scaffold (BVS) had a significantly higher risk of definite or probable scaffold thrombosis (ScT) compared to those treated with metallic DES. The risk of very late ScT was highest with the Absorb BVS among comparators. Pairwise conventional meta-analysis demonstrated that the elevated risk of ScT with Absorb BVS compared to cobalt-chromium everolimus-eluting stents was consistent across the time points of ≤30 days (early), 31 days - 1 year (late) and >1 year (very late) ScT. In addition, target lesion failure rates were significantly higher in the Absorb BVS cohort, driven by both increased risk of target vessel myocardial infarction and ischaemia-driven target lesion revascularisation. CONCLUSIONS: Absorb BVS implantation was associated with increased risk of long-term and very late ScT compared to current-generation metallic DES. The risk of ScT occurred with a rising trend beyond one year.

Discordance Between Fractional Flow Reserve and Coronary Flow Reserve: Insights From Intracoronary Imaging and Physiological Assessment.

OBJECTIVES: The aim of this study was to investigate the epicardial and microvascular substrates associated with discordances between fractional flow reserve (FFR) and coronary flow reserve (CFR) values. BACKGROUND: Discordances between FFR and CFR remain poorly characterized. METHODS: FFR, hyperemic stenosis resistance (HSR), and intravascular ultrasound were performed as indexes of epicardial function and CFR and hyperemic microvascular resistance (HMR) as measures of microvascular function in 94 patients with moderate coronary stenosis. Maximal plaque burden (PBmax), HSR, and HMR were calculated in 4 quadrants based on values of FFR ≤0.80 and CFR ≤2.0 as follows: concordant normal (preserved FFR and CFR), concordant abnormal (low FFR and CFR), discordant low FFR and preserved CFR, and discordant preserved FFR and low CFR. RESULTS: Sixty-four patients (68%) had concordant FFR and CFR findings, and 30 patients (32%) had discordant FFR and CFR. Compared with patients with preserved FFR and CFR, those with low FFR and CFR had higher PBmax (p = 0.003), higher HSR (p < 0.001), and similar HMR. Among patients with preserved FFR, those with reduced CFR had similar PBmax and HSR but a trend toward higher HMR (p = 0.058) compared with patients with preserved CFR. Among patients with reduced FFR, those with preserved CFR had lower PBmax (p = 0.004), a trend toward lower HSR (p = 0.065), and lower HMR (p = 0.03) compared with patients with reduced CFR. Furthermore, compared with patients with preserved FFR and low CFR, those with low FFR and preserved CFR had higher HSR (p = 0.022) but lower HMR (p = 0.003). CONCLUSIONS: In patients with moderate coronary stenosis, preserved FFR and low CFR is associated with increased microvascular resistance, while low FFR and preserved CFR has modest epicardial stenosis and preserved microvascular function.