IMPROvE-CED Trial: Intracoronary Autologous CD34+ Cell Therapy for Treatment of Coronary Endothelial Dysfunction in Patients With Angina and Nonobstructive Coronary Arteries.

BACKGROUND: Coronary endothelial dysfunction (CED) causes angina/ischemia in patients with nonobstructive coronary artery disease (NOCAD). Patients with CED have decreased number and function of CD34+ cells involved in normal vascular repair with microcirculatory regenerative potential and paracrine anti-inflammatory effects. We evaluated safety and potential efficacy of intracoronary autologous CD34+ cell therapy for CED. METHODS: Twenty NOCAD patients with invasively diagnosed CED and persistent angina despite maximally tolerated medical therapy underwent baseline exercise stress test, GCSF (granulocyte colony stimulating factor)-mediated CD34+ cell mobilization, leukapheresis, and selective 1×105 CD34+ cells/kg infusion into left anterior descending. Invasive CED evaluation and exercise stress test were repeated 6 months after cell infusion. Primary end points were safety and effect of intracoronary autologous CD34+ cell therapy on CED at 6 months of follow-up. Secondary end points were change in Canadian Cardiovascular Society angina class, as-needed sublingual nitroglycerin use/day, Seattle Angina Questionnaire scores, and exercise time at 6 months. Change in CED was compared with that of 51 historic control NOCAD patients treated with maximally tolerated medical therapy alone. RESULTS: Mean age was 52±13 years; 75% were women. No death, myocardial infarction, or stroke occurred. Intracoronary CD34+ cell infusion improved microvascular CED (%acetylcholine-mediated coronary blood flow increased from 7.2 [-18.0 to 32.4] to 57.6 [16.3-98.3]%; P=0.014), decreased Canadian Cardiovascular Society angina class (3.7±0.5 to 1.7±0.9, Wilcoxon signed-rank test, P=0.00018), and sublingual nitroglycerin use/day (1 [0.4-3.5] to 0 [0-1], Wilcoxon signed-rank test, P=0.00047), and improved all Seattle Angina Questionnaire scores with no significant change in exercise time at 6 months of follow-up. Historic control patients had no significant change in CED. CONCLUSIONS: A single intracoronary autologous CD34+ cell infusion was safe and may potentially be an effective disease-modifying therapy for microvascular CED in humans. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03471611.

Clonal Hematopoiesis of Indeterminate Potential Is Associated With Coronary Microvascular Dysfunction In Early Nonobstructive Coronary Artery Disease.

BACKGROUND: Clonal hematopoiesis (CH) of indeterminate potential (CHIP) is a risk factor for cardiovascular disease. The relationship between CHIP and coronary microvascular dysfunction (CMD) is unknown. The current study examines the association between CHIP and CH with CMD and the potential relationships in risk for adverse cardiovascular outcomes. METHODS: In this retrospective observational study, targeted next-generation sequencing was performed for 177 participants with no coronary artery disease who presented with chest pain and underwent routine coronary functional angiogram. Patients with somatic mutations in leukemia-associated driver genes in hematopoietic stem and progenitor cells were examined; CHIP was considered at a variant allele fraction ≥2%; CH was considered at a variant allele fraction ≥1%. CMD was defined as coronary flow reserve to intracoronary adenosine of ≤2. Major adverse cardiovascular events considered were myocardial infarction, coronary revascularization, or stroke. RESULTS: A total of 177 participants were examined. Mean follow-up was 12±7 years. A total of 17 patients had CHIP and 28 had CH. Cases with CMD (n=19) were compared with controls with no CMD (n=158). Cases were 56±9 years, were 68% women, and had more CHIP (27%; P=0.028) and CH (42%; P=0.001) than controls. CMD was associated with independent risk for major adverse cardiovascular events (hazard ratio, 3.89 [95% CI, 1.21-12.56]; P=0.023), and 32% of this risk was mediated by CH. The risk mediated by CH was ≈0.5× as large as the direct effect of CMD on major adverse cardiovascular events. CONCLUSIONS: In humans, we observe patients with CMD are more likely to have CHIP, and nearly one-third of major adverse cardiovascular events in CMD are mediated by CH.

The effect of polyphenol-rich chardonnay seed supplements on peripheral endothelial function.

OBJECTIVE: Peripheral endothelial dysfunction (PED) is associated with major adverse cardiovascular events. Similar to cardio-protective Mediterranean diet, Chardonnay seeds are rich in polyphenols, fibers, and grape seed oil. In this randomized double-blinded trial, we investigated safety and incremental benefit of Chardonnay seed polyphenols-rich (PR), compared to polyphenols-free (PF), supplements on PED. METHODS: 89 patients with PED [reactive hyperemia-peripheral arterial tonometry (RH-PAT) index ≤ 2) were randomized 1:1 to 4.8 g (6 capsules)/day PR or PF for 4 months. PR and PF capsules had equal amounts of seed oil (~ 7% capsule weight), fibers, and carbohydrates, but only PR capsules contained polyphenols (~ 11% capsule weight). Baseline and follow-up RH-PAT indices (primary endpoint) and endothelial progenitor cells (EPC) levels were measured. Patients were asked to maintain their regular diet and exercise habits during study period. RESULTS: Baseline RH-PAT indices, demographics, lab values, and EPC levels were similar between groups. No significant adverse reactions to PR or PF were reported. Follow-up RH-PAT indices significantly increased (p < 0.05 vs. baseline) in both groups to similar extent (31 ± 39% PR vs. 49 ± 53% PF, p = 0.09). Circulating CD34 + EPCs equally increased (median + 55% vs. + 54%, p = 0.94) in PR and PF groups, respectively. CONCLUSION: PR and PF Chardonnay seed supplements were safe and improved peripheral endothelial function to similar extent in PED patients. However, there were no incremental benefits of PR over PF on RH-PAT indices or CD34 + EPC levels. Chardonnay seed supplements role in primary prevention of atherosclerosis, as add-on to healthy lifestyle and guidelines directed medical therapy, should be further explored. CLINICALTRIALS. GOV IDENTIFIER (NCT NUMBER): NCT02093455.

Elevated Levels of Serum Fibrin and Fibrinogen Degradation Products Are Independent Predictors of Larger Coronary Plaques and Greater Plaque Necrotic Core.

BACKGROUND: Co-existence of vulnerable plaque and pro-thrombotic state may provoke acute coronary events. It was hypothesized that elevated serum levels of fibrin and fibrinogen degradation products (FDP) are associated with larger total plaque and necrotic core (NC) areas. METHODS AND RESULTS: Seventy-five patients presenting with stable anginal symptoms (69%) or stabilized acute coronary syndrome (ACS; 31%), and found to have non-obstructive coronary artery disease (CAD) with a fractional flow reserve >0.8, were studied. Invasive virtual histology intravascular ultrasound (VH-IVUS) was performed in 68 LAD arteries, 6 circumflex arteries, and 1 right coronary artery. Serum FDP levels were measured using ELISA technique. Plaque volumetrics and composition were assessed in each VH-IVUS frame and averaged. The median age of patients was 56 (47-63) years; 52% were men and 23% had diabetes. The average length of coronary artery studied was 62 mm. After adjustment for systemic risk factors, medications, CRP levels and ACS, male gender (P<0.001) and serum FDP levels (P=0.02) were independent predictors of a larger NC area. Older age (P<0.001), male gender (P<0.0001) and increased serum FDP level (P=0.03) were associated with a larger plaque area. CONCLUSIONS: In patients with CAD, a higher serum level of FDP is independently associated with larger plaques and greater plaque NC.

Fractional flow reserve for the assessment of complex multivessel disease in a patient after hybrid coronary revascularization.

We present a case of a 43-year-old woman with history of hybrid coronary revascularization [endoscopic atraumatic coronary artery bypass (ACAB)] of left internal mammary artery (LIMA) to the left anterior descending artery (LAD) and stent implantation in right coronary artery (RCA), who presented 6 years later with recurrent atypical angina. Coronary angiography revealed patent LIMA to LAD and RCA stent, with a new lesion in an obtuse marginal artery and significant progression of disease in the proximal/mid LAD proximal to LIMA touchdown. To further evaluate the hemodynamic significance of these new disease segments, the patient underwent fractional flow reserve (FFR) assessment of the left coronary system with subsequent stent implantation in the proximal/mid LAD. This case illustrates (1) the critical value of FFR assessment in determining the ischemia provoking lesions in this post ACAB patient with complex multivessel coronary artery disease; and (2) the accelerated progression of atherosclerosis in bypassed segments as compared to segments proximal to stents.

Coronary Reactivity Assessment Is Associated With Lower Health Care-Associated Costs in Patients Presenting With Angina and Nonobstructive Coronary Artery Disease.

BACKGROUND: The financial burden linked to the diagnosis and treatment of patients with chest pain on the health care system is considerable. Angina and nonobstructive coronary artery disease (ANOCA) is common, associated with adverse cardiovascular events, and may lead to repeat testing or hospitalizations. Diagnostic certainty can be achieved in patients with ANOCA using coronary reactivity testing (CRT); however, its financial effect on the patient has not been studied. Our goal was to assess the effect of CRT on health care-related cost in patients with ANOCA. METHODS: Patients with ANOCA who underwent diagnostic coronary angiography (CAG) and CRT (CRT group) were matched to controls who had similar presentation but only underwent a CAG without CRT (CAG group). Standardized inflation-adjusted costs were collected and compared between the 2 groups on an annual basis for 2 years post the index date (CRT or CAG). RESULTS: Two hundred seven CRT and 207 CAG patients were included in the study with an average age of 52.3±11.5 years and 76% females. The total cost was significantly higher in the CAG group as compared with the CRT group ($37 804 [$26 933-$48 674] versus $13 679 [$9447-$17 910]; P<0.001). When costs are itemized and divided based on the Berenson-Eggers Type of Service categorization, the largest cost difference occurred in imaging (any type, including CAG; P<0.001), procedures (eg, percutaneous coronary intervention/coronary artery bypass grafting/thrombectomy) (P=0.001), and test (eg, blood tests, EKG; P<0.001). CONCLUSIONS: In this retrospective observational study, assessment of CRT in patients with ANOCA was associated with significantly reduced annual total costs and health care utilization. Therefore, the study may support the integration of CRT into clinical practice.

Circulating progenitor cells are associated with plaque progression and long-term outcomes in heart transplant patients.

AIMS: Circulating progenitor cells (CPCs) play a role in vascular repair and plaque stability, while osteocalcin (OC) expressing CPCs have been linked to unstable plaque and adverse cardiovascular outcomes. However, their role in cardiac allograft vasculopathy (CAV) has not been elucidated. This cohort study aimed to investigate the contribution of CPCs on CAV progression and cardiovascular events after heart transplantation. METHODS AND RESULTS: A total of 80 heart transplant patients (mean age 55 ± 14 years, 72% male) undergoing annual intravascular ultrasound (IVUS) had fresh CPCs marked by CD34, CD133, and OC counted in peripheral blood using flow cytometry, on the same day as baseline IVUS. CAV progression was assessed by IVUS as the change (Δ) in plaque volume divided by segment length (PV/SL), adjusted for the time between IVUS measurements [median 3.0, interquartile range (2.8-3.1) years] and was defined as ΔPV/SL that is above the median ΔPV/SL of study population. Major adverse cardiac events (MACEs) were defined as any incident of revascularization, myocardial infarction, heart failure admission, re-transplantation, stroke, and death. Patients with higher CD34+CD133+ CPCs had a decreased risk of CAV progression [odds ratio 0.58, 95% confidence interval (CI) (0.37-0.92), P = 0.01] and MACE [hazard ratio (HR) 0.79, 95% CI (0.66-0.99), P = 0.05] during a median (interquartile range) follow-up of 8.0 years (7.2-8.3). Contrarily, higher OC+ cell counts were associated with an increased risk of MACE [HR 1.26, 95% CI (1.03-1.57), P = 0.02]. CONCLUSIONS: Lower levels of CD34+CD133+ CPCs are associated with plaque progression and adverse long-term outcomes in patients who underwent allograft heart transplantation. In contrast, higher circulating OC+ levels are associated with adverse long-term outcomes. Thus, CPCs might play a role in amelioration of transplant vasculopathy, while OC expression by these cells might play a role in progression.

Autologous CD34+ Stem Cell Therapy Increases Coronary Flow Reserve and Reduces Angina in Patients With Coronary Microvascular Dysfunction.

BACKGROUND: Coronary microvascular dysfunction results in angina and adverse outcomes in patients with evidence of ischemia and nonobstructive coronary artery disease; however, no specific therapy exists. CD34+ cell therapy increases microvasculature in preclinical models and improves symptoms, exercise tolerance, and mortality in refractory angina patients with obstructive coronary artery disease. The objective of this research was to evaluate the safety, tolerability, and efficacy of intracoronary CD34+ cell therapy in patients with coronary microvascular dysfunction. METHODS: We conducted a 2-center, 20-participant trial of autologous CD34+ cell therapy (protocol CLBS16-P01; NCT03508609) in patients with ischemia and nonobstructive coronary artery disease with persistent angina and coronary flow reserve ≤2.5. Efficacy measures included coronary flow reserve, angina frequency, Canadian Cardiovascular Society angina class, Seattle Angina Questionnaire, SF-36, and modified Bruce exercise treadmill test obtained at baseline and 6 months after treatment. Autologous CD34+ cells (CLBS16) were mobilized by administration of granulocyte-colony stimulating factor 5µg/kg/day for 5 days and collected by leukapheresis. Participants received a single intracoronary left anterior descending infusion of isolated CD34+ cells in medium that enhances cell function. RESULTS: Coronary flow reserve improved from 2.08±0.32 at baseline to 2.68±0.79 at 6 months after treatment (P<0.005). Angina frequency decreased (P<0.004), Canadian Cardiovascular Society class improved (P<0.001), and quality of life improved as assessed by the Seattle Angina Questionnaire (P≤0.03, all scales) and SF-36 (P≤0.04, all scales). There were no cell-related serious adverse events. CONCLUSIONS: In this pilot clinical trial of microvascular angina, patients with ischemia and nonobstructive coronary artery disease receiving intracoronary infusion of CD34+ cell therapy had higher coronary flow reserve, less severe angina, and better quality of life at 6 months. The current study supports a potential therapeutic role for CD34+ cells in patients with microvascular angina. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03508609.

Sex-specific differences in coronary blood flow and flow velocity reserve in symptomatic patients with non-obstructive disease.

AIMS: Reduced coronary flow velocity reserve (CFVR) is associated with adverse cardiovascular outcomes. Whether CFVR and coronary blood flow (CBF) are similar in men and women with chest pain and non-obstructive CAD remains unknown. We hypothesised sex differences in CFVR and CBF. METHODS AND RESULTS: A total of 1,683 patients with signs/symptoms of ischaemia and angiographically unobstructed coronary arteries (<40% angiographic stenosis) underwent coronary vasomotion evaluation. CFVR was measured as hyperaemic/resting average velocity in the LAD. Mid-LAD diameter was measured with quantitative angiography and CBF calculated at rest (rCBF) and hyperaemia (hCBF). Resting microvascular resistance (rMR) was calculated as mean arterial pressure/rCBF. Of the total number of patients, 1,096 (65%) were women, median age 51 [42, 59] years. Compared to men, women had lower median CFVR (2.7 [2.4, 3.2] vs 3.1 [2.7, 3.6], p<0.001), higher rCBF (49.7 [34.0, 71.1] vs 45.9 [31.8, 68.7] ml/min, p=0.04), lower hCBF (139.5 [93.0, 195.2] vs 147.1 [95.7, 218.6] ml/min, p=0.02), but similar rMR (p=0.82). Female sex was an independent predictor of lower CFVR, higher rCBF, and lower hCBF. CONCLUSIONS: Compared to men, women with signs/symptoms of ischaemia and non-obstructive CAD have lower CFVR, higher rCBF, and lower hCBF. Female sex is a predictor of these sex-specific differences. The clinical diagnostic and prognostic implications of sex differences in coronary physiology need further evaluation.

Atrial Fibrillation and Endothelial Dysfunction: A Potential Link?

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and coronary atherosclerosis is the leading cause of death in the United States and worldwide. Endothelial dysfunction is the earliest clinically detectable form of atherosclerosis. Control of shared AF and coronary atherosclerosis risk factors improves both AF-free survival and vascular endothelial function. Decades of AF research have yielded fundamental insight into AF pathophysiology, but current pharmacological and catheter-based invasive AF therapies have limited long-term efficacy and substantial side effects, possibly because of incomplete understanding of underlying complex AF pathophysiology. We hereby discuss potential mechanistic links between endothelial dysfunction and AF (risk-factor-associated systemic inflammation and oxidative stress, myocardial ischemia, common gene variants, vascular shear stress, and fibroblast growth factor-23), explore a potential new vascular dimension to AF pathophysiology, highlight a growing body of evidence supporting an association between systemic vascular endothelial dysfunction, AF, and stroke, and discuss potential common effective therapies.

Coronary microvascular dysfunction is associated with exertional haemodynamic abnormalities in patients with heart failure with preserved ejection fraction.

AIMS: This study uniquely explored the relationship between coronary microvascular function and exercise haemodynamics using concurrent invasive testing. METHODS AND RESULTS: Fifty-one consecutive patients with unexplained cardiac exertion symptoms, non-obstructive coronary artery disease and normal left ventricular ejection fraction (>50%) underwent haemodynamic exercise assessment and concurrent coronary reactivity testing. Heart failure with preserved ejection fraction (HFpEF) was defined as a pulmonary arterial wedge pressure (PAWP) ≥15 mmHg at rest and/or ≥25 mmHg at peak exercise. Endothelium-independent coronary microvascular dysfunction (CMD) was defined as a coronary flow reserve (CFR) ≤2.5, while endothelium-dependent CMD was defined as ≤50% increase in coronary blood flow (CBF) in response to intracoronary acetylcholine infusions. Patients with HFpEF (n = 22) had significantly lower CFR (2.5 ± 0.6 vs. 3.2 ± 0.7; P = 0.0003) and median %CBF increase in response to intracoronary acetylcholine [1 (-35; 34) vs. 64 (-4; 133); P = 0.002] compared to patients without HFpEF (n = 29). PAWP was significantly higher in patients with endothelium-independent CMD compared to controls during both rest and exercise. This significant elevation was only present during exercise in patients with endothelium-dependent CMD compared to controls. CFR had significant inverse correlations with PAWP at rest (r = -0.31; P = 0.03) and peak exercise (r = -0.47, P = 0.001). CFR also had positive correlations with maximal exercise capacity (in W/kg) (r = 0.33, P = 0.02). CONCLUSIONS: Coronary microvascular function is inversely associated with filling pressures, particularly during exercise. Both types of CMD are associated with higher filling pressures at peak exercise. These findings underscore the potential mechanism and therapeutic target for CMD and HFpEF.

Peripheral microvascular dysfunction is associated with plaque progression and adverse long-term outcomes in heart transplant patients.

AIMS: Cardiac allograft vasculopathy (CAV) is the major cause of increased morbidity and mortality after heart transplantation. Peripheral endothelial dysfunction (PED) is associated with early atherosclerosis and future risk of major adverse cardiovascular events (MACE) in non-heart transplant population. We aimed to investigate the association of PED with future MACE, and plaque progression assessed by intravascular ultrasound (IVUS) after heart transplantation. METHODS AND RESULTS: We included 66 transplant patients who underwent serial IVUS surveillance for CAV and baseline assessment of peripheral endothelial function using reactive hyperaemia peripheral arterial tonometry. PED was defined as reactive hyperaemia index < 2. The primary endpoint of the study was to investigate the association of PED with CAV progression assessed by intravascular ultrasound (IVUS). CAV progression was assessed as the change (Δ) in plaque volume divided by segment length, and Δ plaque index (plaque volume/vessel volume), adjusted for the time between IVUS measurements (median 3.0 [2.2, 3.1] years). The secondary endpoint was to investigate the association between PED and future MACE, which was defined as any incident of revascularization, heart failure hospitalization, stroke, myocardial infarction, re-transplantation, and death. Patients with PED (n = 27) had more yearly plaque progression (0.50 ± 0.66 vs. 0.15 ± 0.50 mm3 /mm/year, P = 0.02) and a higher Δ plaque index (2.41 ± 2.53% vs. 0.69 ± 2.22%, P = 0.01). Patients with PED were more likely to experience MACE during a median follow-up of 8.2 years (interquartile range [7.6, 8.4]), after adjustment for potential cofounders such as age, high-density lipoprotein cholesterol levels, total rejection score, baseline International Society for Heart & Lung Transplantation CAV grade, and indication of transplantation. (hazard ratio 2.15, 95% confidence interval [1.09, 4.23], P = 0.03). CONCLUSIONS: Peripheral endothelial dysfunction is associated with increased plaque progression and adverse long-term cardiovascular outcomes in transplant patients. PED assessment might be a useful clinical tool for risk stratification after heart transplantation.

Risk Stratification of Patients With NonObstructive Coronary Artery Disease Using Resistive Reserve Ratio.

Background Resistive reserve ratio (RRR), or the ratio of baseline to hyperemic microvascular resistance, has prognostic implications in predicting clinical outcomes in patients with obstructive coronary artery disease. However, its value in patients with angina or ischemia with nonobstructive coronary artery disease is unknown. Methods and Results We included 1692 patients with nonobstructive coronary artery disease who underwent invasive coronary vasoreactivity testing. Abnormal coronary flow reserve (CFR, the ratio of hyperemic and baseline resting flow velocities) and RRR were defined as <2.5 and <2.62, respectively. The mortality rate was marginally higher in patients with abnormal CFR (428 patients [25%]) than those with normal CFR (38 [9%] versus 81 [6%]; P=0.08), and was significantly higher in patients with abnormal RRR (716 patients [42%]) than those with normal RRR (70 [10%] versus 49 [5%], P=0.0002) over the median follow-up of 11.3 years. Patients with abnormal CFR had marginally lower survival than those with normal CFR (log-rank P=0.08). In contrast, patients with abnormal RRR had significantly lower survival than those with normal RRR (log-rank P=0.001). Abnormal RRR was associated with shorter time to death even after adjustment for other covariates (adjusted hazard ratio, 1.63; 95% CI, 1.11-2.38; P=0.01). Conclusions In patients with no obstructive coronary artery disease, RRR was superior to CFR in predicting long-term survival. An RRR <2.62 was associated with 1.6 times increased risk of death in patients with nonobstructive coronary artery disease. Indices of coronary microcirculatory resistive reserve comprising flow- and pressure-derived values may reflect underlying microvascular pathology more faithfully than flow-alone indices like CFR.

Rationale and design of a multicenter, randomized, patients-blinded two-stage clinical trial on effects of endothelial function test in patients with non-obstructive coronary artery disease (ENDOFIND).

Abnormal peripheral and coronary endothelial function has been associated with increased risk of major adverse cardiovascular events (MACE) in cross-sectional retrospective and observational studies. However, prognostic value of routine clinical evaluation, diagnosis and treatment of endothelial dysfunction on incident MACE in patients with non-obstructive coronary artery disease (NOCAD) remains unknown. Endothelial Function Guided Management in Patients with NOCAD (ENDOFIND) is a multicenter, randomized, patients-blinded, parallel-controlled, two-stage clinical trial evaluating the impact of routine clinical peripheral endothelial function testing on initiation and/or intensification of cardiovascular preventive therapies in Stage I, and on the risk of MACE in Stage II in patients with NOCAD. One thousand participants with NOCAD on clinically indicated coronary computed tomography or invasive angiography will be enrolled and randomized 1:1, after baseline peripheral endothelial function evaluation, to either endothelial function guided treatment group or standard of care control group. In Stage I, patients will be followed for 12 months and primary outcome will be the proportion of patients receiving prescriptions for cardiovascular evidence-based lipid, blood pressure and glucose lowering medications at the clinic visit immediately after endothelial function evaluation. Secondary outcomes are change in endothelial function measured as reactive hyperemia index and patients' adherence to evidence-based medications in 12 months. Study will be extended into Stage II where sample size and follow up duration will be reevaluated to ensure statistical power, and primary outcome will be incident MACE. ENDOFIND is proof-of-concept clinical trial of a disruptive endothelial function guided clinical intervention with potential benefits to NOCAD patients. CONDENSED ABSTRACT: ENDOFIND is a proof-of-concept clinical trial of a disruptive endothelial function guided clinical intervention with potential benefits to patients with no obstructive coronary artery disease (NOCAD). It is a multicenter, randomized, patients-blinded, parallel controlled two-stage clinical trial to evaluate the impact of routine clinical peripheral endothelial function testing on initiation and/or intensification of cardiovascular disease preventive therapies in Stage I, and on the risk of MACE in Stage II.

Prognostic impact and clinical outcomes of coronary flow reserve and hyperaemic microvascular resistance.

BACKGROUND: Most studies dichotomise indices of coronary microvascular function to assess their prognostic values. AIMS: We aimed to investigate whether coronary flow reserve (CFR) and hyperaemic microvascular resistance (HMR) as continua predict major adverse cardiovascular events (MACE), comprising all-cause death, myocardial infarction, revascularisation, and stroke in patients with ischaemia and non-obstructive coronary artery disease. METHODS: A total of 610 patients were included and followed up over a median of 8.0 years (199 individual MACE in 174 patients). RESULTS: Both CFR and HMR as continua predicted MACE with an odds ratio (OR) of 0.70 (per 1-unit increase, 95% confidence interval [CI]: 0.53, 0.92; p=0.01) and 1.63 (per 1 mmHg/cm/s, 95% CI: 1.20, 2.21; p=0.002), respectively. This relationship remained significant after adjustment for age and sex with an adjusted OR of 0.66 (per 1 unit increase, 95% CI: 0.49, 0.89; p=0.01) and 1.42 (per 1 mmHg/cm/s, 95% CI: 1.03, 1.94; p=0.03). HMR added prognostic value to CFR in predicting MACE (net reclassification index 0.17, 95% CI: 0.02, 0.31; p=0.03; integrated discrimination improvement 0.01, 95% CI: 0.0001, 0.02; p=0.046). CONCLUSIONS: Both CFR and HMR as continuous variables predict future risk of MACE.

Compositional change of gut microbiome and osteocalcin expressing endothelial progenitor cells in patients with coronary artery disease.

Osteogenic endothelial progenitor cells (EPCs) contribute to impaired endothelial repair and promote coronary artery disease (CAD) and vascular calcification. Immature EPCs expressing osteocalcin (OCN) has been linked to unstable CAD; however, phenotypic regulation of OCN-expressing EPCs is not understood. We hypothesized that gut-microbiome derived pro-inflammatory substance, trimethylamine N-oxide (TMAO) might be associated with mobilization of OCN-expressing EPCs. This study aimed to investigate the association between dysbiosis, TMAO, and circulating mature and immature OCN-expressing EPCs levels in patients with and without CAD. We included 202 patients (CAD N = 88; no CAD N = 114) who underwent assessment of EPCs using flow cytometry and gut microbiome composition. Mature and immature EPCs co-staining for OCN were identified using cell surface markers as CD34+/CD133-/kinase insert domain receptor (KDR)+ and CD34-/CD133+/KDR+ cells, respectively. The number of observed operational taxonomy units (OTU), index of microbial richness, was used to identify patients with dysbiosis. The number of immature OCN-expressing EPCs were higher in patients with CAD or dysbiosis than patients without. TMAO levels were not associated with circulating levels of OCN-expressing EPCs. The relative abundance of Ruminococcus gnavus was moderately correlated with circulating levels of immature OCN-expressing EPCs, especially in diabetic patients. Gut dysbiosis was associated with increased levels of TMAO, immature OCN-expressing EPCs, and CAD. The relative abundance of Ruminococcus gnavus was correlated with immature OCN-expressing EPCs, suggesting that the harmful effects of immature OCN-expressing EPCs on CAD and potentially vascular calcification might be mediated by gut microbiome-derived systemic inflammation.