Corban, Michel

Introduction: Coronary microvascular dysfunction (CMD) is prevalent in symptomatic patients with no obstructive coronary artery disease. We postulated that exercise capacity and cardiac output augmentation in response to exercise are linked to coronary microvascular function in this patient population. Methods: Fifty-one consecutive patients with unexplained cardiac exertion symptoms, non-obstructive coronary artery disease on angiography (<50% stenosis), and normal left ventricular ejection fraction (>50%) who underwent concurrent clinically indicated coronary reactivity testing and invasive cardiopulmonary exercise testing (CPEX) were included. Microvascular function was assessed by coronary flow reserve (CFR; hyperemic/resting flow) in response to intracoronary adenosine injection. Cardiac output (CO) was calculated at rest and peak exercise using Fick’s formula. CO limitation was defined as a measured (peak CO - resting CO) <80% than the expected [6*absolute ΔVO 2 (Peak VO 2 -Rest VO 2 ) increase in CO in L/min]. The relationship between CFR, maximal exercise capacity, and CO augmentation at peak exercise was explored. Results: Patients were 56.6±10.5 years old and 73% were females. CFR had a modest positive correlation with measured increase in CO (r=0.42; P=0.003) ( Fig 1A ), and with maximal ergometric exercise capacity [in Watts/Kg] (Pearson’s r=0.33, P=0.02) ( Fig 1B ). Patients with, vs. without impaired cardiac limitations during exercise, had significantly lower CFR levels (2.6±0.5 vs 3.1±0.7; P=0.01) ( Fig 2 ). Conclusion: Impaired coronary microvascular function is associated with lower peak exercise capacity and reduced cardiac output augmentation in response to exercise, underscoring the functional ramification of CMD in symptomatic patients.

Title: Serum NT-proB-type Natriuretic Peptide is associated with Coronary Microvascular Dysfunction in Patients with Angina and Non-obstructive Coronary Artery Disease Authors: Ali Ahmad, MD, Jaskanwal D. Sara, MBChB, Michel T. Corban, MD, Takumi Toya, MD, Ilke Özcan, MD, Lilach O. Lerman, MD PhD, Amir Lerman, MD Introduction: Coronary microvascular dysfunction (CMD) is prevalent in patients with heart failure with preserved ejection fraction. Subclinical ischemia and myocardial fibrosis in CMD might raise filling pressure, a hallmark of HFpEF, which induces secretion of NT-proB-type natriuretic peptide (NTpro-BNP). We sought to explore the relationship between CMD and NT-proBNP. Methods: We studied 698 patients with signs and/or symptoms of ischemia and with non-obstructive CAD (<40% angiographic stenosis) who underwent invasive CMD evaluation and had NT-proBNP checked within 6 weeks. CMD was defined as coronary flow reserve (CFR) (hyperemic flow/baseline flow as measured by the doppler wire) of ≤2.5 in response to intracoronary adenosine injection. Results: Overall mean age was 52.8±12.2 years, and women represented 69% of the patients. Log NT-proBNP showed a modest inverse correlation with CFR (Pearson’s R = -0.22, P<0.0001; Figure 1 ), which remained significant after adjusting for age and gender (Standardized ß coefficient = -0.14; P = 0.001). Patients with CMD had higher levels of NT-proBNP than those without (82 [44-190] vs. 62 (33-130], P <0.0001; Figure 2) . Conclusion: Declining coronary microvascular function is correlated with higher NT-proBNP levels. Patients with CMD had higher levels of NT-proBNP, a marker of elevated LV pressure, contributing to the possible role of CMD in early HFpEF pathophysiology. Keywords: Coronary microvascular dysfunction, NT-proBNP

Background: Microvascular dysfunction is known to play a key role in patients with angina and nonobstructive coronary artery disease. We investigated the impact of ranolazine among patients with angina and nonobstructive coronary artery disease. Methods: In this randomized, double-blinded, placebo-controlled pilot trial, 26 patients with angina once weekly or more, abnormal stress test, and nonobstructive coronary artery disease (<50% stenosis by angiography and fractional flow reserve >0.80) were randomized 1:1 to ranolazine or placebo for 12 weeks. Primary end point was ΔSeattle Angina Questionnaire (SAQ) angina frequency score. Baseline and 3 months follow-up SAQ, Duke Activity Status Index scores along with invasive fractional flow reserve, coronary flow reserve (CFR), hyperemic myocardial resistance, and cardiopulmonary exercise testing measurements were performed. Results: No significant differences in ΔSAQ angina frequency scores ( P =0.53) or Duke Activity Status Index ( P =0.76) were observed between ranolazine versus placebo, although patients on ranolazine had lesser improvement in SAQ physical limitation scores ( P =0.02) compared with placebo at 3 months. There were no significant differences in ΔCFR or Δhyperemic myocardial resistance between ranolazine and placebo groups. Patients treated with ranolazine, compared with placebo, had no significant improvement in maximum rate of oxygen consumption measured during incremental exercise (VO 2 max) and peak metabolic equivalents of task. Interestingly, in the ranolazine group, patients with baseline CFR<2.0 demonstrated greater gain in CFR compared with those with baseline CFR≥2.0 ( P =0.02). Conclusions: Ranolazine did not demonstrate improvement in SAQ angina frequency score, invasive microvascular function, or peak metabolic equivalent compared with placebo at 3 months. Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT02147067.

Abstract Background An Artificial intelligence (AI)-enabled algorithm can provide an age estimate from a single standard resting ECG. The gap between AI-estimated age (ECG age) and chronological age (Age-Gap) has been associated with total and cardiovascular mortality. We hypothesized that coronary endothelial dysfunction (CED), an early feature of coronary atherosclerosis, is associated with physiological aging, as measured by ECG age. Purpose The aim of this study is to investigate the association of CED, a potential index of cardiac aging, and AI-estimated physiological aging. Methods 1902 patients with signs and/or symptoms of ischemia and with non-obstructive coronary artery disease (&lt;40% angiographic stenosis) who underwent functional coronary angiography with intracoronary (IC) acetylcholine (Ach) infusions and a resting ECG within one year were included in this analysis. CED was defined as coronary artery constriction [%ΔCoronary artery diameter (CAD) &lt;0] in response to IC Ach. Patients were categorized as CED+ or CED−. The ECG age were calculated by a previously-trained AI algorithm that was built using the Keras framework with Tensorflow backend and Python. The association between ECG-age and Age-Gap, with CED was investigated. Results Average chronological age was 50.9±12.5, ECG age was 54.1±11.6, 1261 (66%) were females. Compared to CED−, the CED+ group had more males and hyperlipidaemia (p&lt;0.05 for both). Age-gap was significantly higher in patients with CED+ (Fig. A). Multiple regression analysis showed that CED+ was associated with Age-gap (standardized β [sβ] coefficient = 0.08, P=0.001) even after adjustment for chronological age (sβ coefficient = 0.07, P=0.001), and even after adjusting for other cardiovascular risk factors like gender and obesity (sβ coefficient = 0.07, P&lt;0.0001). Furthermore, there is a significant gradual increase in vasoconstriction, in response to IC Ach, with increasing Age-gap (Fig. B). Conclusion Abnormal coronary endothelial function is associated with an increased AI-estimated age which could indicate a higher physiological age. Funding Acknowledgement Type of funding source: None

Abstract Background Artificial Intelligence (AI) algorithms enabled the detection of patients with paroxysmal atrial fibrillation (PAF) from a single normal sinus rhythm (NSR) ECG. Coronary microvascular dysfunction (CMD) is a precursor for coronary artery disease, which is a known risk factor for AF. Purpose The aim of this study is to examine the probability of PAF, according to AI-enabled algorithm estimation, in patients with CMD. Methods 1858 patients without persistent atrial fibrillation with signs and/or symptoms of ischemia and with non-obstructive CAD (&lt;40% stenosis) who underwent invasive coronary microvascular functional assessment and the ECG closest to the functional assessment were included in this analysis. Patients with coronary flow velocity reserve (CFR) &lt;2 in response to adenosine were labelled as endothelial-independent CMD; % increase in coronary blood flow (%ΔCBF) &lt;50% in response to acetylcholine were labelled as endothelial-dependent CMD. Patients were categorized into 4 groups. G1: Normal (NL) CFR/NL %ΔCBF; G2: Abnormal (ABN) %ΔCBF only; G3: ABN CFR only; G4: ABL CFR & %ΔCBF. The probability of having PAF (%probAF) was calculated by a previously-trained and validated AI algorithm. AF Flag = %probAF &gt;9%; which is a pre-set cut-off found to have the highest accuracy of identifying patients with PAF (Area Under the Curve = 0.87). Results Mean age for patients was 51.2±12.4 and 66.3% were females. 835 (45%) were in G1, 39 (2%) in G2, 911 (49%) in G3, and 73 (4%) in G4. Compared to G1 and G2, G3 and G4 were older, had more diabetes and higher smoking rates (p&lt;0.05 for all). Furthermore, G4 had a significantly higher %probAF compared to other groups (Fig. 1). G4 were also more likely to be flagged by the algorithm as having PAF, even after adjusting for cardiovascular risk factors, with an odds ratio of 1.9 [CI 95% 1.1–3.3; p=0.03]) (Fig. 2). Conclusion Patients with combined CMD have a significantly higher probability of having PAF based on an AI-enabled algorithm. Further research is warranted to know if patients with CMD would benefit from formal AF screening at the time of diagnosis. Funding Acknowledgement Type of funding source: None

Introduction: Recent evidence has demonstrated that Clonal Hematopoiesis of Indeterminate Potential (CHIP) increases the risk of cardiovascular events. However, the exact role played by CHIP in early stages of coronary atherosclerosis, characterized by coronary endothelial dysfunction remains to be elucidated. Hypothesis: The current study was designed to test the hypothesis that the presence of CHIP in peripheral blood cells is associated with coronary endothelial dysfunction and increased levels of inflammatory markers. Methods: Next generation sequencing was used to detect mutations among patients who had coronary endothelial dysfunction and control group (normal coronary endothelial function). Endothelial dysfunction was defined by ≥ 20% decrease in coronary artery diameter or ≤50% increase in blood flow in response to acetylcholine injection compared to baseline. Plasma cytokine levels of Interleukin (IL)-6 and IL-8 were also assessed. Results: Clonal hematopoiesis relevant gene mutations were found in 1 out of 64 patients with normal endothelial function (1.5%) and 11 out of 119 cases in the endothelial dysfunction group (9.2%) (P = 0.04) with ASXL1 (Additional sex combs-like 1) being the most frequent gene (4.2%) mutated. Cytokine analysis demonstrated that mutations in ASXL1, DNMT3A (DNA methyltransferase 3A) and TET2 (Ten-eleven-translocation-2) in the endothelial dysfunction group were associated with increased levels of IL-6 and IL-8 (P = 0.001, P = 0.003; respectively). Conclusions: The current study supports a potential role for CHIP in mechanisms of coronary artery disease starting at early stage of atherosclerosis. Furthermore, enhanced expression levels of IL-6 and IL-8 seem to be related to mutations in DNMT3A, ASXL1 and TET2 genes, more than other gene mutations relevant CHIP.

Background Elevated levels of serum homocysteine, via impaired nitric oxide production, and coronary microvascular dysfunction are associated with increased risk of major adverse cardiovascular events. However, whether serum homocysteine levels and coronary microvascular endothelial dysfunction (CMED) are linked remains unknown. Methods and Results This study included 1418 patients with chest pain or an abnormal functional stress test and with nonobstructive coronary artery disease (<40% angiographic stenosis), who underwent CMED evaluation with functional angiography and had serum homocysteine levels measured. Patients were classified as having normal microvascular function versus CMED. Patients in the CMED group (n=743; 52%) had higher mean age (52.1±12.2 versus 50.0±12.4 years; P <0.0001), higher body mass index (29.1 [25.0–32.8] versus 27.5 [24.2–32.4]; P =0.001), diabetes mellitus (12.5% versus 9.4%; P =0.03), and fewer women (63.5% versus 68.7%; P =0.04) compared with patients in the normal microvascular function group. However, they had lower rates of smoking history, and mildly lower low‐density lipoprotein cholesterol levels. Serum homocysteine levels were significantly higher in patients with CMED, and the highest quartile of serum homocysteine level (>9 µmol/L) was an independent predictor of CMED (odds ratio, 1.34 [95% CI, 1.03–1.75]; P =0.03) after adjustment for age; sex; body mass index; chronic kidney disease (CKD); diabetes mellitus; smoking exposure; low‐density lipoprotein cholesterol; high‐density lipoprotein cholesterol and triglycerides; and aspirin, statin, and B vitamin use. Conclusions Patients with CMED have significantly higher levels of serum homocysteine. Elevated serum homocysteine levels were associated with a significantly increased odds of an invasive diagnosis of CMED. The current study supports a potential role for homocysteine for diagnosis and target treatment in the patients with early coronary atherosclerosis.

Abstract Aims We aimed to test the hypothesis that the presence of clonal hematopoiesis of indeterminate potential (CHIP) in peripheral blood cells is associated with coronary endothelial dysfunction, enhanced inflammatory markers, and major adverse cardiovascular events (MACE).Methods and results We compared targeted next generation sequencing (35 CHIP related genes) between patients with coronary endothelial dysfunction (n = 123) and controls (n=65). Coronary endothelial dysfunction was defined by ≥ 20% decrease in coronary artery diameter (CAD) or ≤ 50% increase in coronary blood flow (CBF) in response to acetylcholine injection compared to baseline. Plasma cytokine levels of Interleukin (IL)-6 and IL-8 were also assessed. Patients were subsequently followed for 12.2 ± 4.3 years. Clonal hematopoiesis relevant gene mutations were found in 1 individual in normal endothelial function group (1.5%) and 11 cases in endothelial dysfunction group (9.3%) (p = 0.04). Additionally, CHIP mutations were associated with an increased risk of MACE (OR = 4.08, P = 0.04). Mutations in ASXL1, DNMT3A and TET2 in the endothelial dysfunction group were also associated with increased levels of IL-6 and IL-8 (P = 0.001, P = 0.003; respectively).Conclusion The current study demonstrates a high frequency of CHIP in patients with coronary endothelial dysfunction as well as an association between mutations in three most common epigenetic regulator genes and increased levels of IL-6 and IL-8. Therefore it infers a probable relationship between CHIP, endothelial dysfunction and cardiovascular adverse events.

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.

Background We examined feasibility of a unique approach towards gaining insight into heritable risk for early atherosclerosis: surveying gene expression by endothelial cells from living subjects. Methods and Results Subjects aged <50 years (mean age, 37; range, 22–49) without obstructive coronary artery disease underwent coronary reactivity testing that identified them as having normal or abnormal coronary endothelial function. Cultures of Blood Outgrowth Endothelial Cells (BOEC) from 6 normal and 13 abnormal subjects passed rigorous quality control and were used for microarray assessment of gene expression. Of 9 genes differentially expressed at false discovery rate <0.1%, we here focus upon abnormal subjects having elevated expression of HMGB1 (high mobility group box 1) which we unexpectedly found to be linked to low LAMC1 (laminin gamma 1) expression. This linkage was corroborated by 3 of our past studies and confirmed bio‐functionally. Compared with normal BOEC, abnormal BOEC released 13±3‐fold more HMGB1 in response to lipopolysaccharide; and they deposited one tenth as much LAMC1 into collagen subendothelial matrix during culture. Clinical follow‐up data are provided for 4 normal subjects (followed 13.4±0.1 year) and for 12 abnormal subjects (followed 9.1±4.5 years). Conclusions The known pathogenic effects of high‐ HMGB1 and low‐ LAMC1 predict that the combination would biologically converge upon the focal adhesion complex, to the detriment of endothelial shear responsiveness. This gene expression pattern may comprise a heritable risk state that promotes early coronary atherosclerosis. If so, the testing could be applied even in childhood, enabling early intervention. This approach offers a way to bridge the information gap between genetics and clinical phenotype.