Optical Coherence Tomography-Based Functional Stenosis Assessment: FUSION-A Prospective Multicenter Trial.

BACKGROUND: Intravascular imaging and intracoronary physiology may both be used to guide and optimize percutaneous coronary intervention; however, they are rarely used together. The virtual flow reserve (VFR) is an optical coherence tomography (OCT)-based model of fractional flow reserve (FFR) facilitating the assessment of the physiological significance of coronary lesions. We aimed to validate the VFR assessment of intermediate coronary artery stenoses. METHODS: FUSION (Validation of OCT-Based Functional Diagnosis of Coronary Stenosis) was a multicenter, prospective, observational study comparing OCT-derived VFR to invasive FFR. VFR was mathematically derived from a lumped parameter flow model based on 3-dimensional lumen morphology. Patients undergoing coronary angiography with intermediate angiographic stenosis (40%-90%) requiring physiological assessment were enrolled. Investigational sites were blinded to the VFR analysis, and all OCT and FFR data were reviewed by an independent core laboratory. The coprimary end points were the sensitivity and specificity of VFR against FFR as the reference standard, each of which was tested against prespecified performance goals. RESULTS: After core laboratory review, 266 vessels in 224 patients from 25 US centers were included in the analysis. The mean angiographic diameter stenosis was 65.5%±14.9%, and the mean FFR was 0.83±0.11. Overall accuracy, sensitivity, and specificity of VFR versus FFR using a binary cutoff point of 0.80 were 82.0%, 80.4%, and 82.9%, respectively. The 97.5% lower confidence bound met the prespecified performance goal for sensitivity (71.6% versus 70%; P=0.01) and specificity (76.6% versus 75%; P=0.01). The area under the curve was 0.88 (95% CI, 0.84-0.92; P<0.0001). CONCLUSIONS: OCT-derived VFR demonstrates high sensitivity and specificity for predicting invasive FFR. Integrating high-resolution intravascular imaging with imaging-derived physiology may provide synergistic benefits as an adjunct to percutaneous coronary intervention. REGISTRATION: URL: https://clinicaltrials.gov; Unique identifier: NCT04356027.

Comprehensive Management of ANOCA, Part 1-Definition, Patient Population, and Diagnosis: JACC State-of-the-Art Review.

Angina with nonobstructive coronary arteries (ANOCA) is increasingly recognized and may affect nearly one-half of patients undergoing invasive coronary angiography for suspected ischemic heart disease. This working diagnosis encompasses coronary microvascular dysfunction, microvascular and epicardial spasm, myocardial bridging, and other occult coronary abnormalities. Patients with ANOCA often face a high burden of symptoms and may experience repeated presentations to multiple medical providers before receiving a diagnosis. Given the challenges of establishing a diagnosis, patients with ANOCA frequently experience invalidation and recidivism, possibly leading to anxiety and depression. Advances in scientific knowledge and diagnostic testing now allow for routine evaluation of ANOCA noninvasively and in the cardiac catheterization laboratory with coronary function testing (CFT). CFT includes diagnostic coronary angiography, assessment of coronary flow reserve and microcirculatory resistance, provocative testing for endothelial dysfunction and coronary vasospasm, and intravascular imaging for identification of myocardial bridging, with hemodynamic assessment as needed.

Comprehensive Management of ANOCA, Part 2-Program Development, Treatment, and Research Initiatives: JACC State-of-the-Art Review.

Centers specializing in coronary function testing are critical to ensure a systematic approach to the diagnosis and treatment of angina with nonobstructive coronary arteries (ANOCA). Management leveraging lifestyle, pharmacology, and device-based therapeutic options for ANOCA can improve angina burden and quality of life in affected patients. Multidisciplinary care teams that can tailor and titrate therapies based on individual patient needs are critical to the success of comprehensive programs. As coronary function testing for ANOCA is more widely adopted, collaborative research initiatives will be fundamental to improve ANOCA care. These efforts will require standardized symptom assessments and data collection, which will propel future large-scale clinical trials.

Invasive Coronary Assessment in Myocardial Ischemia with No Obstructive Coronary Arteries.

PURPOSE OF REVIEW: The purpose of this review is threefold: (i) to give an overview of well-established invasive methods for assessing patients with ischemia with no obstructive coronary arteries (INOCA) in the cardiac catheterization laboratory; (ii) to describe the prognostic and treatment implications based on these findings, and (iii) to discuss current knowledge gaps and future perspectives. RECENT FINDINGS: Recent studies have demonstrated that invasive coronary function testing not only allows for risk stratification of patients with INOCA but also guides medical therapy with improvement in symptoms and quality of life. Based on these findings, invasive coronary function assessment is now a class 2a recommendation in the 2021 ACC/AHA chest pain guideline to improve the diagnosis of coronary microvascular dysfunction and to enhance risk stratification. Invasive functional testing for patients with INOCA is well established and easily performed in the catheterization laboratory. Comprehensive invasive assessment is a key to differentiating INOCA endotypes and optimizing both medical therapy and preventive strategies including lifestyle modification.

Case report: Repeat coronary function testing in women with ischemia and no obstructive coronary artery disease.

Women with signs and symptoms of ischemia and no obstructive coronary artery disease (INOCA) often have coronary microvascular dysfunction (CMD). It can be diagnosed by coronary function testing (CFT), which is an invasive coronary angiogram procedure. Frequently, these women have persistent angina despite medical therapy, but it is not clear whether it is due to worsening or persistent CMD or inadequate therapy. In this brief report, we describe findings of repeat CFT in a case series of 12 women undergoing repeat CFT for the assessment of persistent angina in order to better understand the evolving pathology.

Safety of Provocative Testing With Intracoronary Acetylcholine and Implications for Standard Protocols.

BACKGROUND: Heterogeneity in diagnostic criteria and provocation protocols has posed challenges in understanding the safety of coronary provocation testing with intracoronary acetylcholine (ACh) for the contemporary diagnosis of epicardial and microvascular spasm. OBJECTIVES: We examined the safety of testing and subgroup differences in procedural risks based on ethnicity, diagnostic criteria, and provocation protocols. METHODS: PubMed and Embase were searched in November 2021 to identify original articles reporting procedural complications associated with intracoronary ACh administration. The primary outcome was the pooled estimate of the incidence of major complications including death, myocardial infarction, ventricular tachycardia/fibrillation, and shock. RESULTS: A total of 16 studies with 12,585 patients were included in the meta-analysis. The overall pooled estimate of the incidence of major complications was 0.5% (95% CI: 0.0%-1.3%) without any reports of death. Exploratory subgroup analyses revealed that the pooled incidence of major complications was significantly higher in the studies that followed the contemporary diagnosis criteria for epicardial spasm defined as ≥90% diameter reduction (1.0%; 95% CI: 0.3%-2.0%) but significantly lower in Western populations (0.0%; 95% CI: 0.0%-0.45%). The rate of positive epicardial spasm and the incidence of major complications were similar between provocation protocols using the maximum ACh doses of 100 µg and 200 µg. CONCLUSIONS: Intracoronary ACh administration for the contemporary diagnosis of epicardial and microvascular spasm is a safe procedure. Moreover, excellent safety records are observed in Western populations primarily presenting with myocardial ischemia and/or infarction with nonobstructive coronary arteries. This study will help standardize ACh testing to improve clinical diagnosis and ensure procedural safety.

Coronary microvascular dysfunction: Considerations for diagnosis and treatment.

Ischemia and no obstructive coronary artery disease (INOCA) is an increasingly recognized cause of angina, and it is more commonly diagnosed in women. Coronary microvascular dysfunction (CMD), or the abnormal dilation and constriction of the small vessels of the heart, is the underlying cause of INOCA in one-half of cases. This review discusses coronary microvascular pathophysiology, considerations for invasive coronary function testing and noninvasive diagnostic modalities, implications for management, and remaining knowledge gaps.

Angina relates to coronary flow in women with ischemia and no obstructive coronary artery disease.

BACKGROUND: Women with suspected ischemia and no obstructive coronary artery disease (INOCA) often have coronary microvascular dysfunction (CMD) as measured by impaired coronary flow reserve (CFR), which is associated with angina and adverse cardiovascular events. CFR is a ratio of hyperemic to baseline average peak velocity (bAPV), and the relation of baseline flow to angina is not understood. METHODS: We evaluated 259 women enrolled in the WISE-Coronary Vascular Dysfunction (WISE-CVD) project with suspected CMD who underwent invasive coronary functional testing. We analyzed variables stratified by high (e.g. ≥22 cm/s) vs low (<22 cm/s) bAPV, using t-test or Wilcoxon rank; linear and multivariable regression was used with bAPV as a continuous variable. RESULTS: Women with high bAPV had worse Seattle Angina Questionnaire (SAQ) angina frequency (58 ± 26 vs 67 ± 25, p = 0.005) and SAQ-7 scores (57 ± 22 vs 62 ± 21, p = 0.03), with higher nitrate (p = 0.02) and ranolazine use (p = 0.03). The high bAPV subgroup also had lower CFR (p < 0.001)). Linear regression related higher bAPV with lower SAQ-7 (p = 0.01) and lower angina frequency scores (p = 0.001). These results remained significant in multivariable modelling adjusting for baseline differences (p < 0.04). SAQ-7 was significantly predicted by bAPV. CONCLUSIONS: Among women with suspected INOCA, angina relates to high bAPV, a result supported by the concomitant greater use of anti-anginal drugs. These results suggest that high bAPV contributes to impaired CFR and may represent a specific pathophysiologic contributor to CMD and may be a treatment target in INOCA subjects.

Relationship between coronary function testing and migraine: results from the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction project.

Aim: To determine the relationship between coronary vascular dysfunction and history of migraines in women with suspected ischemia and no obstructive coronary arteries (INOCA). Methods: In the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction study, 402 women with suspected INOCA answered baseline angina questionnaires, including the Seattle Angina Questionnaire (SAQ). Coronary function testing (CFT) performed in a subgroup of 252 women evaluated for nonendothelial and endothelial-dependent coronary vascular function. Wilcoxon rank sum test, t-test, and linear regression models were performed. Results: Of the 252 women who underwent CFT, 126 (50%) women reported migraine history. Compared to women who reported no migraines, women with migraines were younger and more were premenopausal. They had more angina at rest, with strong emotions, and hot/cold temperatures, as well as angina that wakes them from sleep (P < 0.05 for all). Women with migraines also scored worse on SAQ angina frequency and quality of life P < 0.01 for both). There was no difference in prevalence of coronary vascular dysfunction in the two groups. In addition, linear regression models demonstrated no significant age-adjusted differences in absolute CFT variables. Conclusion: Among women with suspected INOCA, migraine history is prevalent and women with migraines have worse angina compared to those without migraines. Coronary vascular dysfunction diagnosed by CFT does not appear to relate to migraine history.

Coronary Vascular Function and Cardiomyocyte Injury: A Report From the WISE-CVD.

OBJECTIVE: Women with symptoms or signs of myocardial ischemia but no obstructive coronary artery disease (INOCA) often have coronary vascular dysfunction and elevated risk for adverse cardiovascular events. We hypothesized that u-hscTnI (ultra-high-sensitivity cardiac troponin I), a sensitive indicator of ischemic cardiomyocyte injury, is associated with coronary vascular dysfunction in women with INOCA. Approach and Results: Women (N=263) with INOCA enrolled in the WISE-CVD study (Women's Ischemic Syndrome Evaluation-Coronary Vascular Dysfunction) underwent invasive coronary vascular function testing and u-hscTnI measurements (Simoa HD-1 Analyzer; Quanterix Corporation, Lexington, MA). Logistic regression models, adjusted for traditional cardiovascular risk factors were used to evaluate associations between u-hscTnI and coronary vascular function. Women with coronary vascular dysfunction (microvascular constriction and limited coronary epicardial dilation) had higher plasma u-hscTnI levels (both P=0.001). u-hscTnI levels were associated with microvascular constriction (odds ratio, 1.38 per doubling of u-hscTnI [95% CI, 1.03-1.84]; P=0.033) and limited coronary epicardial dilation (odds ratio, 1.37 per doubling of u-hscTnI [95% CI, 1.04-1.81]; P=0.026). u-hscTnI levels were not associated with microvascular dilation or coronary epicardial constriction. CONCLUSIONS: Our findings indicate that higher u-hscTnI is associated with coronary vascular dysfunction in women with INOCA. This suggests that ischemic cardiomyocyte injury in the setting of coronary vascular dysfunction has the potential to contribute to adverse cardiovascular outcomes observed in these women. Additional studies are needed to confirm and investigate mechanisms underlying these findings in INOCA. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00832702.

Angina Hospitalization Rates in Women With Signs and Symptoms of Ischemia But no Obstructive Coronary Artery Disease: A Report from the WISE (Women's Ischemia Syndrome Evaluation) Study.

Background Recurrent hospitalization is prevalent in women with signs and symptoms of ischemia and no obstructive coronary artery disease. We hypothesized that rates of angina hospitalization might have changed over time, given advances in diagnostic and therapeutic approaches. Methods and Results We evaluated 551 women enrolled in the WISE (Women's Ischemia Syndrome Evaluation) study with no obstructive coronary artery disease (CAD) for a follow-up period of 9.1 years. We analyzed angina hospitalization rates using the Kaplan-Meier method. Univariate analysis and multivariable Cox proportional hazard models were developed for prediction of angina hospitalization in women with signs and symptoms of angina and no CAD. A total of 223 women had nonobstructive CAD (>20-50%

Resting coronary velocity and myocardial performance in women with impaired coronary flow reserve: Results from the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD) study.

BACKGROUND: Women with evidence of ischemia and no obstructive coronary arteries (INOCA) often have coronary microvascular dysfunction (CMD) indicated by impaired coronary flow reserve (CFR) to adenosine. Low CFR is associated with an adverse prognosis, including incident heart failure. Because the CFR calculation relies on the baseline intrinsic coronary vasomotor flow velocity, a major determinate of CFR and the degree of variation in baseline flow alone may be an important contributor to risk of adverse outcomes in women with CMD. A better understanding of baseline blood flow in the setting of low CFR and its association with myocardial performance would be helpful. METHODS: We evaluated 74 women who underwent invasive coronary reactivity testing in the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD) study and had impaired CFR (<2.32). We assessed the relationship between coronary artery baseline average peak velocity (bAPV) at rest and cardiac magnetic resonance imaging measures of left ventricular (LV) structure and function. RESULTS: When stratified as low (<22 cm/s) versus high (≥22 cm/s) bAPV, there were no differences in cardiovascular risk factors, coronary plaque burden, or LV structure. However, low bAPV was associated with higher LV end-diastolic filling pressure (P = 0.04), lower LV ejection fraction (P = 0.001), and differences in late systolic and diastolic strain rates (P = 0.01 to 0.05). CONCLUSIONS: In women with impaired CFR, low resting coronary flow velocity is associated with more adverse myocardial performance, which may contribute to risk for adverse outcomes and particularly heart failure in women with CMD.

Prevalence of Coronary Endothelial and Microvascular Dysfunction in Women with Symptoms of Ischemia and No Obstructive Coronary Artery Disease Is Confirmed by a New Cohort: The NHLBI-Sponsored Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD).

OBJECTIVE: In a separate, contemporary cohort, we sought to confirm findings of the original Women's Ischemia Syndrome Evaluation (WISE). BACKGROUND: The original WISE observed a high prevalence of both invasively determined coronary endothelial and coronary microvascular dysfunction (CMD) that predicted adverse events in follow-up. METHODS: We comparatively studied the WISE-Coronary Vascular Dysfunction (CVD) cohort (2009-2011), with signs and symptoms of ischemia but without significant CAD, to the original WISE (1997-2001) cohort. CMD was defined as coronary flow reserve (CFR) ≤2.5, or endothelial dysfunction as epicardial coronary artery constriction to acetylcholine (ACH), or <20% epicardial coronary dilation to nitroglycerin (NTG). RESULTS: In WISE (n=181) and WISE-CVD (n=235) women, mean age in both was 54 years, and 83% were white (WISE) vs 74% (WISE-CVD, p=0.04). Use of hormone replacement therapy was less frequent in WISE-CVD vs WISE (46% vs 57%, p=0.026) as was presence of hypertension (40% vs 52%, p=0.013), hyperlipidemia (20% vs 46%, p<0.0001), and smoking (46% vs 56%, p=0.036). Similar rates were observed in WISE-CVD and WISE cohorts for CMD (mean CFR 2.7±0.6 vs 2.6±0.8, p=0.35), mean change in diameter with intracoronary ACH (0.2±10.0 vs 1.6±12.8 mm, p=0.34), and mean change in diameter with intracoronary NTG (9.7±13.0 vs 9.8±13.5 mm, p=0.94), respectively. CONCLUSIONS: This study confirms prevalence of CMD in the contemporary WISE-CVD cohort similar to that of the original WISE cohort, despite a lower risk factor burden in WISE-CVD. Because these coronary functional abnormalities predict major adverse cardiac events, clinical trials of therapies targeting these abnormalities are indicated.

The functional assessment of patients with non-obstructive coronary artery disease: expert review from an international microcirculation working group.

Symptomatic non-obstructive coronary artery disease (NOCAD) is an increasingly recognised entity that is associated with poor cardiovascular outcomes. Nearly half of those undergoing coronary angiography for appropriate indications, such as typical angina, or a positive stress test have no obstructive lesion. There are no guideline recommendations as to how to care properly for these patients. Physiologic assessment of the coronary arteries beyond two-dimensional angiography is not standardised, yet it can provide valuable information in patients presenting with typical angina in the setting of NOCAD. In this consensus document, we detail steps for the interventional cardiologist to evaluate the patient with symptomatic NOCAD in the cardiac catheterisation laboratory, first with the assessment of coronary flow reserve (CFR), and then with delineation of deficiencies in non-endothelium-dependent CFR (CFRne) versus endothelium-dependent CFR (CFRe) using provocative agents such as adenosine and acetylcholine, respectively, followed by the evaluation of smooth muscle function with nitroglycerine (NTG). Once the mechanism behind the anginal symptoms is established, one can identify the appropriate treatment strategies to address the physiologic deficiency that is present. Despite an established safety profile, a comprehensive assessment may be considered for selected patients which requires an understanding of the appropriate invasive evaluation by the practising interventional cardiologist when evaluating not only patients with obstructive CAD but also those with NOCAD.

Maladaptive left ventricular remodeling in women: An analysis from the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction study.

BACKGROUND: Women represent approximately half of heart failure hospitalizations and are disproportionately affected by heart failure with preserved ejection fraction (HFpEF). Women with signs and symptoms of ischemia, preserved left ventricular ejection fraction (LVEF), and no obstructive coronary artery disease (CAD) often have elevated left ventricular end-diastolic pressure (LVEDP). However, isolated elevated LVEDP in the absence of coronary microvascular dysfunction (CMD) is not understood. METHODS: Among 244 women with signs and symptoms of ischemia, no obstructive CAD, and preserved LVEF who underwent invasive coronary reactivity testing (CRT), 43 (18%) women had no evidence of CMD. LVEDP was measured at time of CRT, and left ventricular (LV) volumes and mass were assessed by cardiac magnetic resonance (CMR) imaging. RESULTS: Of the 43 women without CMD, 24 (56%) had elevated LVEDP [mean 18 mm Hg (SD = 3)] compared to 19 (44%) with normal LVEDP [11 mm Hg (SD = 3)]. The elevated LVEDP group had a comparatively higher systolic and diastolic blood pressure, lower LV end-diastolic volume index (EDVI), and higher mass-to-volume ratio. Other functional parameters were not significantly different. CONCLUSIONS: Among women with signs and symptoms of ischemia without obstructive CAD, absence of CMD, and preserved LVEF, isolated elevated LVEDP is associated with a significantly higher systolic and diastolic blood pressure, higher LV mass-to-volume ratio and lower LV EDVI. These results suggest these women have maladaptive remodeling to blood pressure. Given the relatively high prevalence of HFpEF in women, these hypothesis-generating results suggest that further study of ventricular remodeling is warranted.

The State of the Absorb Bioresorbable Scaffold: Consensus From an Expert Panel.

Significant progress has been made in the percutaneous coronary intervention technique from the days of balloon angioplasty to modern-day metallic drug-eluting stents (DES). Although metallic stents solve a temporary problem of acute recoil following balloon angioplasty, they leave behind a permanent problem implicated in very late events (in addition to neoatherosclerosis). BRS were developed as a potential solution to this permanent problem, but the promise of these devices has been tempered by clinical trials showing increased risk of safety outcomes, both early and late. This is not too dissimilar to the challenges seen with first-generation DES in which refinement of deployment technique, prolongation of dual antiplatelet therapy, and technical iteration mitigated excess risk of very late stent thrombosis, making DES the treatment of choice for coronary artery disease. This white paper discusses the factors potentially implicated in the excess risks, including the scaffold consideration and deployment technique, and outlines patient and lesion selection, implantation technique, and dual antiplatelet therapy considerations to potentially mitigate this excess risk with the first-generation thick strut Absorb scaffold (Abbott Vascular, Abbott Park, Illinois). It remains to be seen whether these considerations together with technical iterations will ultimately close the gap between scaffolds and metal stents for short-term events while at the same time preserving options for future revascularization once the scaffold bioresorbs.

Role of Stress Cardiac Magnetic Resonance Imaging in Women with Suspected Ischemia but No Obstructive Coronary Artery Disease.

OBJECTIVE: Signs and symptoms of ischemia but no obstructive coronary artery disease (CAD) is often a diagnostic dilemma in women. The use of stress cardiac magnetic resonance imaging (CMRI) for advanced diagnostic assessment in these patients is a non-ionizing radiation option, but the diagnostic utility in this population is unknown. We examined the diagnostic role of stress CMRI in our patient population of these women. METHODS: We analyzed 113 consecutive female patients from 2/2006-11/2007 who had prior cardiac evaluations for signs and symptoms of ischemia but no obstructive CAD who underwent stress CMRI, which included anatomic, functional, adenosine stress perfusion and delayed enhancement imaging. RESULTS: The population demographics of 113 women included a mean age of 55±12.2 years with an average body mass index (BMI) of 25 ± 4.5. Overall, 43% had hypertension, 4% had diabetes and 3% were smokers. Overall, 80/113 (70%) demonstrated abnormal stress CMRI results. The majority of patients demonstrated findings consistent with subendocardial perfusion abnormalities suggestive of coronary microvascular dysfunction (CMD). Of note, 3 patients (4%) were diagnosed with congenital coronary anomalies or cardiomyopathy not detected in prior cardiac evaluations. CONCLUSION: Among women with signs and symptoms of ischemia but no obstructive CAD, stress CMRI is frequently abnormal and is valuable in diagnosis of CMD. Stress CMRI appears useful for advanced diagnostic assessment in these diagnostically challenged patients.