Coronary flow reserve and cardiovascular outcomes: a systematic review and meta-analysis

Optimizing Management of Stable Angina: A Patient-Centered Approach Integrating Revascularization, Medical Therapy, and Lifestyle Interventions

Angina pectoris may arise from obstructive coronary artery disease (CAD) or in the absence of significant CAD (ischemia with nonobstructed coronary arteries [INOCA]). Therapeutic strategies for patients with angina and obstructive CAD focus on reducing cardiovascular events and relieving symptoms, whereas in INOCA the focus shifts toward managing functional alterations of the coronary circulation. In obstructive CAD, coronary revascularization might improve angina status, although a significant percentage of patients present angina persistence or recurrence, suggesting the presence of functional mechanisms along with epicardial CAD. In patients with INOCA, performing a precise endotype diagnosis is crucial to allow a tailored therapy targeted toward the specific pathogenic mechanism. In this expert opinion paper, we review the evidence for the management of angina, highlighting the complementary role of coronary revascularization, optimal medical therapy, and lifestyle interventions and underscoring the importance of a personalized approach that targets the underlying pathobiology.

Changes in absolute coronary flow and microvascular resistance during exercise in patients with ANOCA

BACKGROUND

Whether saline-induced hyperaemia captures exercise-induced coronary flow regulation remains unknown.

AIMS

Through this study, we aimed to describe absolute coronary flow (Q) and microvascular resistance (Rμ) adaptation during exercise in participants with angina with non-obstructive coronary artery disease (ANOCA) and to explore the correlations between saline- and exercise-derived coronary flow reserve (CFR) and microvascular resistance reserve (MRR).

METHODS

Rμ, Q, CFR and MRR were assessed in the left anterior descending artery using continuous thermodilution with saline infusion at 10 mL/min (rest), 20 mL/min (hyperaemia) and finally at a 10 mL/min infusion rate during stress testing with a dedicated supine cycling ergometer. An incremental workload of 30 watts every two minutes was applied. A saline-derived CFR (CFRsaline) cutoff <2.5 was used to identify coronary microvascular dysfunction (CMD).

RESULTS

CFRsaline-defined CMD was observed in 53.3% of the participants (16/30). While cycling, these patients less of an ability to increase Q (7 [interquartile range [IQR] 30.5-103.0] vs 21 [IQR 5.8-45.0] mL/min/30 watts; p=0.01) due to a smaller decrease of Rμ (109 {IQR 32-286} vs 202 [IQR 102-379] Wood units [WU]/30 watts; p<0.01) as compared with the group with normal CFRsaline. In the overall population, CFRsaline and exercise-derived CFR (CFRexercise) were 2.70±0.90 and 2.85±1.54, respectively, with an agreement classification of 83.3%. A good correlation between saline and exercise techniques for both CFR (r=0.73; p<0.0001) and MRR (r=0.76; p<0.0001) was observed. Among participants with normal CFRsaline, 28.7% (4/14) had an impaired CFRexercise <2.5 at the peak of exercise due to a moderate and late decrease of Rμ.

CONCLUSIONS

Saline-induced hyperaemia provided a valid surrogate for exercise physiology independently of the absolute level of CFR and MRR, although exercise provided more granularity to evaluate adaptation among participants with exercise-related CMD.

Impact of the use of plaque modification techniques on coronary microcirculation using an angiography-derived index of microcirculatory resistance

Many lesions in patients undergoing percutaneous coronary intervention (PCI) exhibit significant calcification. Several techniques have been developed to improve outcomes in this setting. However, their impact on coronary microcirculation remains unknown. The aim of this study is to evaluate the influence of plaque modification techniques on coronary microcirculation across patients with severely calcified coronary artery disease. In this multicenter retrospective study, consecutive patients undergoing PCI with either Rotablation (RA) or Shockwave-intravascular-lithotripsy (IVL) were included. Primary endpoint was the impairment of coronary microvascular resistances assessed by Δ angiography-derived index of microvascular resistance (ΔIMRangio) which was defined as the difference in IMRangio value post- and pre-PCI. Secondary endpoints included the development of peri procedural PCI complications (flow-limiting coronary dissection, slow-flow/no reflow during PCI, coronary perforation, branch occlusion, failed PCI, stroke and shock developed during PCI) and 12-month follow-up adverse events. 162 patients were included in the analysis. Almost 80% of patients were male and the left descending anterior artery was the most common treated vessel. Both RA and IVL led to an increase in ΔIMRangio (22.3 and 10.3; p = 0.038, respectively). A significantly higher rate of PCI complications was observed in patients with ΔIMRangio above the median of the cohort (21.0% vs. 6.2%; p = 0.006). PCI with RA was independently associated with higher ΔIMRangio values (OR 2.01, 95% CI: 1.01-4.03; p = 0.048). Plaque modification with IVL and RA during PCI increases microvascular resistance. Evaluating the microcirculatory status in this setting might help to predict clinical and procedural outcomes and to optimize clinical results.

Factors Contributing to Coronary Microvascular Dysfunction in Patients with Angina and Non-Obstructive Coronary Artery Disease

BACKGROUND

Coronary microvascular dysfunction (CMD), characterised by a reduced coronary flow reserve (CFR) or an increased index of microcirculatory resistance (IMR), has received considerable attention as a cause of chest pain in recent years. However, the risks and causes of CMD remain unclear; therefore, effective treatment strategies have not yet been established. Heart failure or coronary artery disease (CAD) is a risk factor for CMD, with a higher prevalence among women. However, the other contributing factors remain unclear. In this study, we assessed the risk in patients with angina and non-obstructive coronary artery disease (ANOCA), excluding those with heart failure or organic stenosis of the coronary arteries. Furthermore, we analysed whether the risk of CMD differed according to component factors and sex.

METHODS

This study included 84 patients with ANOCA (36 men and 48 women; mean age, 63 years) who underwent coronary angiography and functional testing (CFT). The CFT included a spasm provocation test (SPT), followed by a coronary microvascular function test (CMVF). In the SPT, patients were mainly provoked by acetylcholine (ACh), and coronary spasm was defined as >90% transient coronary artery constriction on coronary angiography, accompanied by chest pain or ischaemic changes on electrocardiography. In 15 patients (18%) with negative ACh provocation, ergonovine maleate (EM) was administered as an additional provocative drug. In the CMVF, a pressure wire was inserted into the left anterior descending coronary artery using intravenous adenosine triphosphate, and the CFR and IMR were measured using previously described methods. A CFR < 2.0 or IMR ≥ 25 was indicative of CMD. The correlations between various laboratory indices and CMD and its components were investigated, and logistic regression analysis was performed, focusing on factors where p < 0.05.

RESULTS

Of the 84 patients, a CFR < 2.0 was found in 22 (26%) and an IMR ≥ 25 in 40 (48%) patients, with CMD identified in 46 (55%) patients. CMD was correlated with smoking (p = 0.020) and the use of EM (p = 0.020). The factors that correlated with a CFR < 2.0 included the echocardiograph index E/e' (p = 0.013), which showed a weak but positive correlation with the CFR (r = 0.268, p = 0.013). Conversely, the factors correlated with an IMR ≥ 25 included RAS inhibitor usage (p = 0.018) and smoking (p = 0.042). Assessment of the risk of CMD according to sex revealed that smoking (p = 0.036) was the only factor associated with CMD in men, whereas the left ventricular mass index (p = 0.010) and low glycated haemoglobin levels (p = 0.012) were associated with CMD in women.

CONCLUSIONS

Our results indicated that smoking status and EM use were associated with CMD. The risk of CMD differed between the two CMD components and sex. Although these factors should be considered when treating CMD, smoking cessation remains important. In addition, CMD assessment should be performed carefully when EM is used after ACh provocation. Further validation of our findings using prospective studies and large registries is warranted.

Graphene Oxide Significantly Modifies Cardiac Parameters and Coronary Endothelial Reactivity in Healthy and Hypertensive Rat Hearts Ex Vivo

Interactions of graphene oxide (GO) with an ex vivo rat heart and its coronary vessels have not been studied yet. Moreover, the conflicting data on the "structure-properties" relationships do not allow for biomedical applications of GO. Herein, we study the impact of GO on the ex vivo isolated rat heart, normotensive and hypertensive, under the working heart and the constant-pressure perfusion (Langendorff) regimes. Four structural GO variants of the following initial morphology were used: few-layer (below 10-layer) GO1, O < 49%; predominantly single-layer GO2, O = 41-50%; 15-20-layer GO3, O < 11%; and few-layer (below 10-layer) NH4 +-functionalized GO4, O < 44%, N = 3-6%. The aqueous GO dispersions, sonicated and stabilized with bovine serum albumin in Krebs-Henseleit-like solution-uniformized in terms of the particle size-were eventually size-monodisperse as revealed by dynamic light scattering. To study the cardiotoxicity mechanisms of GO, histopathology, Raman spectroscopy, analysis of cardiac parameters (coronary and aortic flows, heart rate, aortic pressure), and nitric oxide (NO-)-dependent coronary flow response to bradykinin (blood-vessel-vasodilator) were used. GO1 (10 mg/L) exerted no effects on cardiac function and preserved an increase in coronary flow in response to bradykinin. GO2 (10 mg/L) reduced coronary flow, aortic pressure in normotensive hearts, and coronary flow in hypertensive hearts, and intensified the response to bradykinin in normal hearts. GO3 (10 mg/L) reduced all parameters in hypertensive hearts and coronary response to bradykinin in normal hearts. At higher concentrations (normotensive hearts, 30 mg/L), the coronary response to bradykinin was blocked. GO4 (10 mg/L) reduced the coronary flow in normal hearts, while for hypertensive hearts, all parameters, except the coronary flow, were reduced and the coronary response to bradykinin was blocked. The results showed that a low number of GO layers and high O-content were safer for normal and hypertensive rat hearts. Hypertensive hearts deteriorated easier upon perfusion with low-O-content GOs. Our findings support the necessity of strict control over the GO structure during organ perfusion and indicate the urgent need for personalized medicine in biomedical applications of GO.

Parathyroid hormone-PTH1R signaling in cardiovascular disease and homeostasis

Primary hyperparathyroidism (pHPT) afflicts our aging population with an incidence approaching 50 per 100 000 patient-years at a female:male ratio of ~3:1. Decisions surrounding surgical management are currently driven by age, hypercalcemia severity, presence of osteoporosis, renal insufficiency, or hypercalciuria with or without nephrolithiasis. Cardiovascular (CV) disease (CVD) is not systematically considered. This is notable since the parathyroid hormone (PTH) 1 receptor (PTH1R) is biologically active in the vasculature, and adjusted CV mortality risk is increased almost threefold in individuals with pHPT who do not meet contemporary recommendations for surgical cure. We provide an overview of epidemiology, pharmacology, and physiology that highlights the need to: (i) identify biomarkers that establish a healthy 'set point' for CV PTH1R signaling tone; (ii) better understand the pharmacokinetic-pharmacodynamic (PK-PD) relationships of PTH1R ligands in CV homeostasis; and (iii) incorporate CVD risk assessment into the management of hyperparathyroidism.

Stratified medicine for acute and chronic coronary syndromes: A patient-tailored approach

The traditional approach to management of cardiovascular disease relies on grouping clinical presentations with common signs and symptoms into pre-specified disease pathways, all uniformly treated according to evidence-based guidelines ("one-size-fits-all"). The goal of precision medicine is to provide the right treatment to the right patients at the right time, combining data from time honoured sources (e.g., history, physical examination, imaging, laboratory) and those provided by multi-omics technologies. In patients with ischemic heart disease, biomarkers and intravascular assessment can be used to identify endotypes with different pathophysiology who may benefit from distinct treatments. This review discusses strategies for the application of stratified management to patients with acute and chronic coronary syndromes.

A Systematic Approach to the Evaluation of the Coronary Microcirculation Using Bolus Thermodilution: CATH CMD

Coronary microvascular dysfunction (CMD) can cause myocardial ischemia in patients presenting with angina without obstructive coronary artery disease (ANOCA). Evaluating for CMD by using the thermodilution technique offers a widely accessible means of assessing microvascular resistance. Through this technique, 2 validated indices, namely coronary flow reserve and the index of microcirculatory resistance, can be computed, facilitating investigation of the coronary microcirculation. The index of microcirculatory resistance specifically estimates minimum achievable microvascular resistance within the coronary microcirculation. We aim to review the bolus thermodilution method, outlining the fundamental steps for conducting measurements and introducing an algorithmic approach (CATH CMD) to systematically evaluate the coronary microcirculation. Embracing a standardized approach, exemplified by the CATH CMD algorithm, will facilitate adoption of this technique and streamline the diagnosis of CMD.

Type 2 diabetes mellitus in acute myocardial infarction: a persistent significant burden on long-term mortality

Objective

The long-term impact of type 2 diabetes mellitus (T2DM) after an acute myocardial infarction (AMI) has not been thoroughly investigated yet. This study aimed to assess the long-term impact of T2DM after AMI.

Research design and methods

We analyzed the data of three nationwide observational studies from the French Registry of Acute ST-elevation and non-ST-elevation Myocardial Infarction (FAST-MI) program, conducted over a 1-month period in 2005, 2010, and 2015. Patients presenting T2DM were classified as diabetic, and patients presenting type 1 diabetes mellitus were excluded. We identified factors related to all-cause death at 1-year follow-up and divided 1,897 subjects into two groups, paired based on their estimated 1-year probability of death as determined by a logistic regression model.

Results

A total of 9,181 AMI patients were included in the analysis, among them 2,038 (22.2%) had T2DM. Patients with diabetes were significantly older (68.2 ± 12.0 vs. 63.8 ± 14.4, p < 0.001) and had a higher prevalence of a prior history of percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG), or heart failure (22.5% vs. 13.0%, 7.1% vs. 3.1% and 6.7 vs. 3.8% respectively, p < 0.001 for all). Even after matching two groups of 1,897 patients based on propensity score for their 1-year probability of death, diabetes remained associated with long-term mortality, with an HR of 1.30, 95%CI (1.17-1.45), p < 0.001.

Conclusions

T2DM per se has an adverse impact on long-term survival after myocardial infarction. Independently of the risk of short-term mortality, patients with diabetes who survived an AMI have a 30% higher risk of long-term mortality.

WISP-1 Regulates Cardiac Fibrosis by Promoting Cardiac Fibroblasts' Activation and Collagen Processing

Hypertension induces cardiac fibrotic remodelling characterised by the phenotypic switching of cardiac fibroblasts (CFs) and collagen deposition. We tested the hypothesis that Wnt1-inducible signalling pathway protein-1 (WISP-1) promotes CFs' phenotypic switch, type I collagen synthesis, and in vivo fibrotic remodelling. The treatment of human CFs (HCFs, n = 16) with WISP-1 (500 ng/mL) induced a phenotypic switch (α-smooth muscle actin-positive) and type I procollagen cleavage to an intermediate form of collagen (pC-collagen) in conditioned media after 24h, facilitating collagen maturation. WISP-1-induced collagen processing was mediated by Akt phosphorylation via integrin β1, and disintegrin and metalloproteinase with thrombospondin motifs 2 (ADAMTS-2). WISP-1 wild-type (WISP-1+/+) mice and WISP-1 knockout (WISP-1-/-) mice (n = 5-7) were subcutaneously infused with angiotensin II (AngII, 1000 ng/kg/min) for 28 days. Immunohistochemistry revealed the deletion of WISP-1 attenuated type I collagen deposition in the coronary artery perivascular area compared to WISP-1+/+ mice after a 28-day AngII infusion, and therefore, the deletion of WISP-1 attenuated AngII-induced cardiac fibrosis in vivo. Collectively, our findings demonstrated WISP-1 is a critical mediator in cardiac fibrotic remodelling, by promoting CFs' activation via the integrin β1-Akt signalling pathway, and induced collagen processing and maturation via ADAMTS-2. Thereby, the modulation of WISP-1 levels could provide potential therapeutic targets in clinical treatment.

Impact of hyperaemic stenosis resistance on long-term outcomes of stable angina in the ILIAS Registry

BACKGROUND

The hyperaemic stenosis resistance (HSR) index was introduced to provide a more comprehensive indicator of the haemodynamic severity of a coronary lesion. HSR combines both the pressure drop across a lesion and the flow through it. As such, HSR overcomes the limitations of the more traditional fractional flow reserve (FFR) or coronary flow reserve (CFR) indices.

AIMS

We aimed to identify the diagnostic and prognostic value of HSR and evaluate the clinical implications.

METHODS

Patients with chronic coronary syndromes (CCS) and obstructive coronary artery disease were selected from the multicentre ILIAS Registry. For this study, only patients with combined Doppler flow and pressure measurements were included.

RESULTS

A total of 853 patients with 1,107 vessels were included. HSR more accurately identified the presence of inducible ischaemia compared to FFR and CFR (area under the curve 0.71 vs 0.66 and 0.62, respectively; p<0.005 for both). An abnormal HSR measurement was an independent and important predictor of target vessel failure at 5-year follow-up (hazard ratio 3.80, 95% confidence interval: 2.12-6.73; p<0.005). In vessels deferred from revascularisation, HSR seems to identify more accurately those vessels that may benefit from revascularisation rather than FFR and/or CFR.

CONCLUSIONS

The present study affirms the theoretical advantages of the HSR index for the detection of ischaemia-Âinducing coronary lesions in a large CCS population. (Inclusive Invasive Physiological Assessment in Angina Syndromes Registry [ILIAS Registry], ClinicalTrials.gov: NCT04485234).

Effects of age on microvascular function in patients with normal coronary arteries

BACKGROUND

It has been suggested that coronary microvascular function decreases with age, irrespective of the presence of epicardial atherosclerosis.

AIMS

Our aim is to quantitatively investigate the effects of age on microvascular function in patients with normal coronary arteries.

METHODS

In 314 patients with angina with no obstructive coronary artery disease (ANOCA), microcirculatory function was tested using the continuous thermodilution method. In 305 patients, the association between age and both resting and hyperaemic myocardial blood flow (Q), microvascular resistance (Rμ), absolute coronary flow reserve (CFR) and microvascular resistance reserve (MRR) was assessed. In addition, patients were divided into 3 groups to test for differences based on age quartiles (≤52 years [24.9%], 53-64 years [49.2%], ≥65 years [25.9%]).

RESULTS

The mean age was 59±9 years with a range from 22 to 79 years. The mean resting Q (Qrest) was not different in the 3 age groups (88±34 mL/min, 82±29 mL/min, and 86±38 mL/min, R2=0.001; p=0.62). A trend towards a decreasing mean hyperaemic Q (Qmax) was observed with increasing age (223±79 mL/min, 209±84 mL/min, 200±80 mL/min, R2=0.010; p=0.083). The mean resting Rμ (Rμ,rest) were 1,204±460 Wood units (WU), 1,260±411 WU, and 1,289±455 WU (p=0.23). The mean hyperaemic Rμ (Rμ,hyp) increased significantly with advancing age (429±149 WU, 464±164 WU, 503±162 WU, R2=0.026; p=0.005). Consequently, MRR decreased with age (3.2±1.2, 3.1±1.0, 2.9±0.9; p=0.038). This trend was present in both the patients with (n=121) and without (n=184) coronary microvascular dysfunction (CMD).

CONCLUSIONS

There is an age-dependent physiological increase in minimal microvascular resistance and decrease in microvascular function, which is represented by a decreased MRR and is independent of atherosclerosis. The age-dependent decrease in MRR was present in both patients with and without CMD and was most evident in patients with smooth coronary arteries.

Angina pectoris 2023: With and without obstructive coronary artery disease: Epidemiology, diagnosis, prognosis, and treatment

Angina contributes to significant morbidity worldwide. The evaluation of angina is variable and complicated by multiple factors. The diagnosis is often focussed on epicardial disease despite the knowledge that chest pain can be due to cardiac, non-cardiac, macro, and microvascular causes. Standardised diagnostic pathways and novel approaches to angina assessment may offer the opportunity to improve our understanding of angina and apply a personalised approach to treatment.

Cross-sectional study on the impact of adverse childhood experiences on coronary flow reserve in male physicians with and without occupational burnout

OBJECTIVE

Physicians face documented challenges to their mental and physical well-being, particularly in the forms of occupational burnout and cardiovascular disease. This study examined the previously under-researched intersection of early life stressors, prolonged occupational stress, and cardiovascular health in physicians.

METHODS

Participants were 60 practicing male physicians, 30 with clinical burnout, defined by the Maslach Burnout Inventory, and 30 non-burnout controls. They completed the Adverse Childhood Experiences (ACE) Questionnaire asking about abuse, neglect and household dysfunctions before the age of 18, and the Perceived Stress Scale to rate thoughts and feelings about stress in the past month. Endothelium-independent (adenosine challenge) coronary flow reserve (CFR) and endothelium-dependent CFR (cold pressor test) were assessed by positron emission tomography-computed tomography. The segment stenosis score was determined by coronary computed tomography angiography.

RESULTS

Twenty-six (43%) participants reported at least one ACE and five (8%) reported ≥4 ACEs. A higher ACEs sum score was associated with lower endothelium-independent CFR (r partial (rp) = -0.347, p = .01) and endothelium-dependent CFR (rp = -0.278, p = .04), adjusting for age, body mass index, perceived stress and segment stenosis score. In exploratory analyses, participants with ≥4 ACEs had lower endothelium-independent CFR (rp = -0.419, p = .001) and endothelium-dependent CFR (rp = -0.278, p = .04), than those with <4 ACEs. Endothelium-dependent CFR was higher in physicians with burnout than in controls (rp = 0.277, p = .04). No significant interaction emerged between burnout and ACEs for CFR.

CONCLUSION

The findings suggest an independent association between ACEs and CFR in male physicians and emphasize the nuanced relationship between early life stressors, professional stress, and cardiovascular health.

Prognostic Implications of Fractional Flow Reserve and Coronary Flow Reserve After Drug-Eluting Stent Implantation

BACKGROUND

Fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) provides prognostic information, but limited data are available regarding prognostication using post-PCI coronary flow reserve (CFR). In this study we aimed to assess the prognostic value of post-procedural FFR and CFR for target vessel failure (TVF) after PCI.

METHODS AND RESULTS

This lesion-based post-hoc pooled analysis of previously published registry data involved 466 patients with chronic coronary syndrome with single-vessel disease who underwent pre- and post-PCI FFR and CFR measurements, and were followed-up to determine the predictors of TVF. The prognostic value of post-PCI CFR and FFR was compared with that of FFR or CFR alone. Post-PCI FFR/CFR discordant results were observed in 42.5%, and 10.3% of patients had documented TVF. Receiver-operating characteristic curve analysis revealed that the optimal cutoff values of post-PCI FFR and CFR to predict the occurrence of TVF were 0.85 and 2.26, respectively. Significant differences in TVF were detected according to post-PCI FFR (≤0.85 vs. >0.85, P=0.007) and post-PCI CFR (<2.26 vs. ≥2.26, P<0.001). Post-PCI FFR ≤0.85 and post-PCI CFR <2.26 were independent prognostic predictors.

CONCLUSIONS

After PCI completion, discordant results between FFR and CFR were not uncommon. Post-PCI CFR categorization showed incremental prognostic value for predicting TVF independent of post-PCI FFR risk stratification.

Self-supervised deep representation learning of a foundation transformer model enabling efficient ECG-based assessment of cardiac and coronary function with limited labels

Background: Although deep learning methods have shown great promise for identification of structural and functional cardiac abnormalities using electrocardiographic data, these methods are data hungry, posing a challenge for critically important tasks where ground truth labels are relatively scarce. Impaired coronary microvascular and vasomotor function is difficult to identify with standard clinical methods of cardiovascular testing such as coronary angiography and noninvasive single photon emission tomography (SPECT) myocardial perfusion imaging (MPI). Gold standard data from positron emission tomography (PET) are gaining emphasis in clinical guidelines but are expensive and only available in relatively limited centers. We hypothesized that signals embedded within resting and stress electrocardiograms (ECGs) identify individuals with microvascular and vasomotor dysfunction. Methods: We developed and pretrained a self-supervised foundation vision transformer model using a large database of unlabeled ECG waveforms (N=800,035). We then fine-tuned the foundation model for two clinical tasks: the difficult problem of identifying patients with impaired myocardial flow reserve (AI-MFR), and the relatively easier problem of detecting impaired LVEF (AI-LVEF). A second ECG database was labeled with task-specific annotations derived from quantitative PET MPI (N=4167). Diagnostic accuracy of AI predictions was tested in a holdout set of patients undergoing PET MPI (N=1031). Prognostic evaluation was performed in the PET holdout cohort, as well as independent cohorts of patients undergoing pharmacologic or exercise stress SPECT MPI (N=6635). Results: The diagnostic accuracy of AI-MFR with SSL pretraining increased significantly compared to de novo supervised training (AUROC, sensitivity, specificity: 0.758, 70.1%, 69.4% vs. 0.632, 66.1%, 57.3%, p < 0.0001). SSL pretraining also produced a smaller increase in AI-LVEF accuracy (AUROC, sensitivity, specificity: 0.946, 89.4%, 85.9% vs. 0.918, 87.6%, 82.5%, p < 0.02). Abnormal AI-MFR was found to be significantly associated with mortality risk in all three test cohorts (Hazard Ratio (HR) 2.61 [95% CI 1.83, 3.71], p < 0.0001, PET cohort; HR 2.30 [2.03, 2.61], p < 0.0001, pharmacologic stress SPECT cohort; HR 3.76 [2.36, 5.99], p < 0.0001, exercise stress SPECT cohort). Conclusion: SSL pretraining of a vision transformer foundation model enabled identification of signals predictive of impaired MFR, a hallmark of microvascular and vasomotor dysfunction, and impaired LV function in resting and stress ECG waveforms. These signals are powerful predictors of prognosis in patients undergoing routine noninvasive stress testing and could enable more efficient diagnosis and management of these common conditions.

Association Between Global Sleep Quality and Coronary Microvascular Function in Male Physicians With Occupational Burnout

OBJECTIVE

Occupational burnout has been associated with an increased risk of coronary heart disease, although the mechanisms involved are elusive. We investigated whether poor global sleep quality is associated with impaired coronary microvascular function in male physicians, a professional group at increased risk of burnout.

METHODS

Study participants were 30 male physicians with clinical burnout and 30 controls without burnout defined by the Maslach Burnout Inventory. Global sleep quality was measured with the Pittsburgh Sleep Quality Index (PSQI). Endothelium-dependent (cold pressor test) and endothelium-independent (adenosine challenge) coronary microvascular functions were quantified with myocardial perfusion positron emission tomography. In multivariable analyses, the interaction between burnout and the PSQI global score was regressed on measures of coronary microvascular function, adjusting for age, body mass index, physical activity, alcohol consumption, and main effects of burnout and PSQI score.

RESULTS

The prevalence of poor sleepers (PSQI score >5) was 40% in the burnout group and 10% in the control group. Adjusting for covariates, burnout-by-global PSQI score interactions were observed for myocardial blood flow (MBF) at rest ( r partial = -0.30, p = .025), endothelium-dependent coronary flow reserve ( r partial = -0.26, p = .062), MBF response ( r partial = -0.30, p = .028), and hyperemic MBF ( r partial = -0.34, p = .012). The global PSQI score was inversely associated with these MBF measures in the burnout group relative to the control group. No significant interactions emerged for endothelium-independent MBF.

CONCLUSIONS

In male physicians with occupational burnout, poor global sleep quality was associated with reduced endothelium-dependent coronary microvascular function, suggesting a mechanism by which burnout may affect cardiovascular health.

Nonobstructive epicardial coronary artery disease: an evolving concept in need of diagnostic and therapeutic guidance

For decades, we have been treating patients presenting with angina and concerning electrocardiographic changes indicative of ischemia or injury, in whom no culprit epicardial coronary stenosis was found during diagnostic coronary angiography. Unfortunately, the clinical outcomes of these patients were not better than those with recognized obstructive coronary disease. Improvements in technology have allowed us to better characterize these patients. Consequently, an increasing number of patients with ischemia and no obstructive coronary artery disease (INOCA) or myocardial infarction in the absence of coronary artery disease (MINOCA) have now gained formal recognition and are more commonly encountered in clinical practice. Although both entities might share functional similarities at their core, they pose significant diagnostic and therapeutic challenges. Unless we become more proficient in identifying these patients, particularly those at higher risk, morbidity and mortality outcomes will not improve. Though this field remains in constant flux, data continue to become available. Therefore, we thought it would be useful to highlight important milestones that have been recognized so we can all learn about these clinical entities. Despite all the progress made regarding INOCA and MINOCA, many important knowledge gaps continue to exist. For the time being, prompt identification and early diagnosis remain crucial in managing these patients. Even though we are still not clear whether intensive medical therapy alters clinical outcomes, we remain vigilant and wait for more data.

Coronary Flow Velocity Reserve Declines After Anthracycline Therapy in Breast Cancer Patients

Anthracycline therapy (ANT) is associated with cancer therapy-related cardiac dysfunction. Coronary flow velocity reserve (CFVR) has shown prognostic utility in non-cancer cohorts, but no data have been obtained in a cardio-oncology setting. We investigated the acute effect of ANT on CFVR in breast cancer patients. A total of 12 female breast cancer patients undergoing ANT had pre- and post-ANT CFVR assessment. A significant decline in CFVR occurred (baseline: 2.66 ± 0.41 vs post-ANT: 2.47 ± 0.37, P = 0.016). This prospective study is the first to identify ANT-related coronary physiology changes in humans. Further studies are required to determine their clinical significance.

Coronary Microvascular Dysfunction Is Present Among Well-Treated Asymptomatic Persons With HIV and Similar to Those With Diabetes

Background

Coronary microvascular dysfunction (CMD) could be a potential underlying mechanism for myocardial disease in HIV.

Methods

Comparisons of coronary flow reserve corrected for heart rate-blood pressure product (CFRCOR) were made among people with HIV (PWH) with no known history of cardiovascular disease (CVD) or diabetes mellitus, persons without HIV (PWOH), and persons with diabetes (PWDM) and no known history of CVD or HIV.

Results

PWH (n = 39, 74% male, age 55 [7] years, body mass index [BMI] 32.3 (26.8-34.9) kg/m2, duration of antiretroviral therapy 13 [5] years, CD4+ count 754 [598-961] cells/μL) were similar to PWOH (n = 69, 74% male, age 55 [8] years, BMI 32.2[25.6-36.5] kg/m2) and PWDM (n = 63, 63% male, age 55 [8] years, BMI 31.5 [28.6-35.6] kg/m2). CFRCOR was different among groups: PWOH 2.76 (2.37-3.36), PWH 2.47 (1.92-2.93), and PWDM 2.31 (1.98-2.84); overall P = .003. CFRCOR was reduced comparing PWH to PWOH (P = .04) and PWDM to PWOH (P = .007) but did not differ when comparing PWH to PWDM (P = .98). A total 31% of PWH had CFRCOR < 2.0, a critical cutoff for CMD, compared to 14% of PWOH and 27% with PWDM. A total 40% of women with HIV had a CFRCOR < 2.0 compared to 6% of women without HIV (P = .02).

Conclusions

Subclinical CMD is present among chronically infected and well-treated, asymptomatic PWH who are immunologically controlled. This study demonstrates CFR is reduced in PWH compared to PWOH and comparable to PWDM, further highlighting that well-treated HIV infection is a CVD-risk enhancing factor for CMD similar to diabetes. Clinical Trials Registration: NCT02740179.

The role of coronary microvascular dysfunction in the pathogenesis of heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is a common condition with few effective therapies and hence represents a major healthcare burden. The clinical syndrome of HFpEF can be caused by varying pathophysiological processes, with coronary microvascular dysfunction (CMD) proposed as one of the aetiologies, although confirming causality has been challenging. CMD is characterised by the inability of the coronary vasculature to augment blood flow in response to a physiological stressor and has been established as the driver of angina in patients with non-obstructed coronaries (ANOCA), and this has subsequently led to efficacious endotype-directed therapies. CMD is also highly prevalent among sufferers of HFpEF and may represent a novel treatment target for this particular endotype of this condition. This review aims to discuss the role of the microcirculation in the healthy heart how it's dysfunction may precipitate HFpEF and explore the current diagnostic tools available. We also discuss the gaps in evidence and where we believe future research should be focussed.

Stress Echocardiography by the ABCDE Protocol ln the Assessment of Prognosis of Stable Coronary Heart Disease

AIM

To assess the role of clinical indicators and parameters of stress echocardiography performed according to an extended protocol as predictors for the occurrence of a composite cardiovascular endpoint (CCVEP) in IHD.

MATERIAL AND METHODS

The study included 186 patients (60.2% men, mean age 60.6±9.9 years) with an established (n=73; 39.2%) and suspected (60.8%) diagnosis of IHD. Stress EchoCG with adenosine triphosphate (38.2%), transesophageal pacing (15.1%), dobutamine (2.6%), and bicycle ergometry on a recumbent ergometer (44.1%) was performed. The stress EchoCG protocol included assessment of regional wall motion abnormalities (WMA), B-lines, LV contractile reserve (CTR), coronary reserve (CR), and heart rate reserve. The median follow-up period was 13 [9; 20] months. The composite CCVEP included death from cardiovascular diseases and their complications, acute coronary syndrome, and revascularization and was defined at the first of these events. Statistical analysis was performed with the Statistica 16.0 and SPSS Statistics 23.0 software packages. Differences were considered statistically significant at p<0.05.

RESULTS

Invasive or noninvasive coronary angiography was performed in 90.3% of patients; obstructive coronary disease (stenosis ≥50%) was detected in 67.9% of cases. During the follow-up period, 58 (31.2%) patients had cardiovascular complications. The risk of developing CCVEP was associated with the pretest probability (PTP) of ischemic heart disease (odds ratio, OR, 1.05; 95% confidence interval, CI, 1.02-1.08), dyslipidemia (DLP) (OR 0.40; 95% CI 0.20-0.82), carotid atherosclerosis (OR 0.39; 95% CI 0.18-0.86), LV ejection fraction (OR 0.96; 95% CI 0.93-0.99), appearance at peak stress of new significant (2 LV segments or more) regional WMAs (OR 0.32; 95% CI 0.18-6.55), decreased LV CTR (OR 0.46; 95% CI 0.27-0.79) and CR (OR 0.33; 95% CI 0.18-0.61); p<0.05 for all. In a multivariate analysis with Cox regression, the model with clinical indicators included PTP of IHD (OR 1.04; 95% CI 1.01-1.07; p=0.01) and DLP (OR 0.14; 95% CI 0.02-1.01; p=0.05) as predictors. The model with stress EchoCG parameters included the appearance of new significant WMAs (OR 0.33, 95% CI 0.16-0.65; p=0.001) and reduced <2.0 CR (OR 0.44; 95% CI 0.24-0.82; p=0.01). A comparative analysis of Kaplan-Meier curves confirmed statistically significant differences in the dynamics of the CCVEP occurrence depending on the absence or presence of hemodynamically significant WMAs and/or reduced CR during stress EchoCG (p<0.01).

CONCLUSION

Reduced LV CR and WMA during stress EchoCG in patients with suspected or confirmed IHD are significant independent predictors for the CCVEP occurrence. Among clinical indicators, PTP of IHD and DLP are of the greatest importance for prognosis.

Going beyond summed stress scores: Correlating global and territorial coronary flow reserve by single photon emission tomography with routine myocardial perfusion imaging

a Background

Technological advancement in the recent years has enabled the application of single photon emission tomography (SPECT) to evaluate myocardial blood flow (MBF). This method offers increased sensitivity in the assessment of coronary health, quantifiable through non-invasive imaging beyond the more conventional methods such as with myocardial perfusion imaging (MPI).

b Aims

To correlate MBF, derived by dynamic SPECT, both global and by coronary territories to the summed stress scores (SSS) on conventional MPI.

c Methods

Images obtained from dipyridamole-gated SPECT MPI stress and rest studies performed on recruited subjects were examined. We calculated the global and regional coronary flow reserve (CFR) via a standard software package, taken as the ratio of stress MBF to rest MBF, using CFR<2.5 as the cut off.

d Results

Amongst the 90 recruited subjects (mean age 67 ± 8 years; of which 76% were males), 49% had MPI within normal limits (summed stress score (SSS) 0-3; Left ventricular ejection fraction (LVEF) > 50%). We observed a progressive reduction in global and regional CFR across the normal SSS category to that of severely abnormal (SSS >13). Reduced global CFR with correspondent lower CFR across the regional arteries were detected in scans within normal limits of MPI scans in subjects who were older (69 ± 7 vs. 62 ± 9 years, p = 0.034). Decreasing CFR was significantly associated with increasing age across the regional arteries.

e Conclusion

In our study we depict the global and regional MBF values obtained via SPECT MPI in correlation to the respective SSS categories. Our data proposes that dynamic SPECT has a part in refining cardiac risk stratification, particularly in the older adult population, who are at greater risk.

Correlation of Non-Invasive Transthoracic Doppler Echocardiography with Invasive Doppler Wire-Derived Coronary Flow Reserve and Their Impact on Infarct Size in Patients with ST-Segment Elevation Myocardial Infarction Treated with Primary Percutaneous Coronary Intervention

Background: Coronary microvascular dysfunction is associated with adverse prognosis after ST-segment elevation myocardial infarction (STEMI). We aimed to compare the invasive, Doppler wire-based coronary flow reserve (CFR) with the non-invasive transthoracic Doppler echocardiography (TTDE)-derived CFR, and their ability to predict infarct size. Methods: We included 36 patients with invasive Doppler wire assessment on days 3-7 after STEMI treated with primary percutaneous coronary intervention (PCI), of which TTDE-derived CFR was measured in 47 vessels (29 patients) within 6 h of the invasive Doppler. Infarct size was assessed by cardiac magnetic resonance at a median of 8 months. Results: The correlation between invasive and non-invasive CFR was modest in the overall cohort (rho 0.400, p = 0.005). It improved when only measurements in the LAD artery were considered (rho 0.554, p = 0.002), with no significant correlation in the RCA artery (rho -0.190, p = 0.435). Both invasive (AUC 0.888) and non-invasive (AUC 0.868) CFR, measured in the recanalized culprit artery, showed a good ability to predict infarct sizes ≥18% of the left ventricular mass, with the optimal cut off values of 1.85 and 1.80, respectively. Conclusions: In patients with STEMI, TTDE- and Doppler wire-derived CFR exhibit significant correlation, when measured in the LAD artery, and both have a similarly strong association with the final infarct size.

Impact of vessel volume on thermodilution measurements in patients with coronary microvascular dysfunction

BACKGROUND

Two invasive methods are available to estimate microvascular resistance: bolus and continuous thermodilution. Comparative studies have revealed a lack of concordance between measurements of microvascular resistance obtained through these techniques.

AIMS

This study aimed to examine the influence of vessel volume on bolus thermodilution measurements.

METHODS

We prospectively included patients with angina with non-obstructive coronary arteries (ANOCA) undergoing bolus and continuous thermodilution assessments. All patients underwent coronary CT angiography to extract vessel volume. Coronary microvascular dysfunction was defined as coronary flow reserve (CFR) < 2.0. Measurements of absolute microvascular resistance (in Woods units) and index of microvascular resistance (IMR) were compared before and after volumetric adjustment.

RESULTS

Overall, 94 patients with ANOCA were included in this study. The mean age was 64.7 ± 10.8 years, 48% were female, and 19% had diabetes. The prevalence of CMD was 16% based on bolus thermodilution, while continuous thermodilution yielded a prevalence of 27% (Cohen's Kappa 0.44, 95% CI 0.23-0.65). There was no correlation in microvascular resistance between techniques (r = 0.17, 95% CI -0.04 to 0.36, p = 0.104). The adjustment of IMR by vessel volume significantly increased the agreement with absolute microvascular resistance derived from continuous thermodilution (r = 0.48, 95% CI 0.31-0.63, p < 0.001).

CONCLUSIONS

In patients with ANOCA, invasive methods based on coronary thermodilution yielded conflicting results for the assessment of CMD. Adjusting IMR with vessel volume improved the agreement with continuous thermodilution for the assessment of microvascular resistance. These findings strongly suggest the importance of considering vessel volume when interpreting bolus thermodilution assessment.

Prognostic value of combined fractional flow reserve and pressure-bounded coronary flow reserve: outcomes in FFR and Pb-CFR assessment

BACKGROUND

Coronary flow reserve (CFR) has an emerging role to predict outcome in patients with and without flow-limiting stenoses. However, the role of its surrogate pressure bounded-CFR (Pb-CFR) is controversial. We investigated the usefulness of combined use of fractional flow reserve (FFR) and Pb-CFR to predict outcomes.

METHODS

This is a sub-study of the PROPHET-FFR Trial, including patients with chronic coronary syndrome and functionally tested coronary lesions. Patients were divided into four groups based on positive or negative FFR (cut-off 0.80) and preserved (lower boundary ≥2) or reduced (upper boundary <2) Pb-CFR: Group1 FFR≤0.80/ Pb-CFR <2; Group 2 FFR≤0.80/Pb-CFR≥2; Group 3 FFR >0.80/Pb-CFR<2; Group 4 FFR>0.80/Pb-CFR≥2. Lesions with positive FFR were treated with PCI. Primary endpoint was the rate of major adverse cardiac events (MACEs), defined as a composite of death from any cause, myocardial infarction, target vessel revascularization, unplanned cardiac hospitalization at 36-months.

RESULTS

A total of 609 patients and 816 lesions were available for the analysis. At Kaplan-Meier analysis MACEs rate was significantly different between groups (36.7% Group 1, 27.4% Group 2, 19.2% Group 3, 22.6% Group 4, P=0.019) and more prevalent in groups with FFR≤0.80 irrespective of Pb-CFR. In case of discrepancy, no difference in MACEs were observed between groups stratified by Pb-CFR. FFR≤0.80 was associated with an increased MACEs rate (30.2% vs. 21.5%, P<0.01) while Pb-CFR<2 was not (24.5% vs. 24.2% Pb-CFR≥2 P=0.67).

CONCLUSIONS

FFR confirms its ability to predict outcomes in patients with intermediate coronary stenoses. Pb-CFR does not add any relevant prognostic information.

Combined Assessment of Fractional Flow Reserve and Coronary Flow Velocity Reserve after Drug-Eluting Stent Implantation

BACKGROUND

Coronary flow velocity reserve (CFVR) can be measured noninvasively using stress transthoracic Doppler echocardiography (S-TDE). The prognostic significance of S-TDE-derived CFVR after percutaneous coronary intervention (PCI) remains unknown. The aim of this study was to investigate the prognostic value of post-PCI CFVR and its additional efficacy to fractional flow reserve (FFR) in patients undergoing elective PCI.

METHODS

A retrospective study was conducted involving 187 consecutive patients with chronic coronary syndrome who underwent elective PCI guided by FFR for the left anterior descending coronary artery. Pre- and post-PCI wire-based FFR and CFVR assessments of the left anterior descending coronary artery using S-TDE were performed in all patients. The association between post-PCI clinical and physiologic parameters and major adverse cardiac events (MACE), defined as a composite of cardiac death, myocardial infarction, heart failure, and unplanned remote target vessel revascularization, was evaluated.

RESULTS

Three-quarters of patients exhibited CFVR increase after PCI, while all patients showed FFR improvement. During a median follow-up period of 1.5 years, MACE occurred in 21 patients (11.2%). Among clinical demographics, patients with MACE had higher levels of N-terminal pro-brain natriuretic peptide compared with those without MACE (median, 615 pg/mL [interquartile range, 245-1,500 pg/mL] vs 180 pg/mL [interquartile range, 70-559 pg/mL]; P = .010). Post-PCI S-TDE-derived CFVR was lower in patients with MACE, while post-PCI FFR showed a nonsignificant tendency to be lower in patients with MACE. In a multivariable analysis, higher NT-proBNP (adjusted hazard ratio, 1.33; 95% CI, 1.02-1.74; P = .038), post-PCI CFVR ≤ 2.0 (adjusted hazard ratio, 2.93; 95% CI, 1.16-7.40; P = .023), and post-PCI FFR ≤ 0.82 (adjusted hazard ratio, 3.93; 95% CI, 1.52-10.18; P = .005) were independently associated with MACE.

CONCLUSIONS

In patients with chronic coronary syndrome who underwent successful elective PCI for left anterior descending coronary artery, the combined assessment of S-TDE-derived post-PCI CFVR and post-PCI FFR provided a significant association with the occurrence of MACE.

Spectrum of Ischemic Heart Disease Throughout a Woman's Life Cycle

Ischemic heart disease (IHD) is the leading cause of morbidity and mortality in both genders; however, young women fare the worst, likely reflecting the more complex spectrum of IHD in women when compared to men. Substantial sex-based differences exist in the underlying risk factors, risk enhancers, presentation, diagnosis, and pathophysiology of IHD that are mainly attributed to the influence of female sex hormones. This article reviews the spectrum of IHD including obstructive epicardial coronary artery disease (CAD), myocardial infarction with no obstructive coronary artery disease, ischemia with no obstructive coronary artery disease, spontaneous coronary artery dissection, coronary microvascular dysfunction, vasospastic angina, and coronary thrombosis/embolism that occur in women throughout various stages of their life cycle. We aim to update clinicians on the diagnosis and management of these various types of IHD and highlight where further randomized controlled studies are needed to determine optimal treatment and inform guideline-directed medical therapy.

The prevalence of coronary microvascular dysfunction (CMD) in heart failure with preserved ejection fraction (HFpEF): a systematic review and meta-analysis

To date, studies on the prevalence of coronary microvascular dysfunction (CMD) in heart failure with preserved ejection fraction (HFpEF) have not been summarized and analyzed as a whole. We conducted this systematic review and meta-analysis to assess the prevalence of CMD in patients with HFpEF. The PubMed, Cochrane, and Embase databases were searched from dates of inception until May 1, 2023. The primary outcome was the prevalence of CMD in patients with HFpEF, and values of CMD prevalence were pooled using a random-effects model. In total, 10 studies involving 1267 patients, including 822 with HFpEF and 445 without HFpEF, were included. The pooled prevalence of CMD in patients with HFpEF was 71% (95% CI, 0.63-0.79). In the subgroup analysis, the prevalence of CMD was 79% (95% CI, 0.71-0.87) by invasive measurement and 66% (95% CI, 0.54-0.77) by noninvasive measurement and 67% (95% CI, 0.52-0.82) with CFR < 2.0 and 75.0% (95% CI, 0.71-0.79) with CFR < 2.5. The prevalence of endothelium-independent CMD and endothelium-dependent CMD was 62% (95% CI, 0.53-0.72) and 50% (95% CI, 0.19-0.81), respectively. The prevalence of CMD was 74% (95% CI = 0.69-0.79) and 66% (95% CI = 0.41-0.90) in prospective and retrospective studies, respectively. Compared with the control group, patients with HFpEF had a significantly lower CFR (MD =  - 1.28, 95% CI =  - 1.82 to - 0.74, P < 0.01) and a higher prevalence of CMD (RR = 2.21, 95% CI = 1.52 to 3.20, P < 0.01). Qualitative analysis demonstrated that CMD might be associated with poor clinical outcomes in patients with HFpEF. In conclusion, this is the first systematic review and meta-analysis of all studies reporting the prevalence of CMD in patients with HFpEF. Our study demonstrates that CMD is common in patients with HFpEF and might be associated with poor clinical outcomes in these patients. Clinicians should attach importance to CMD in the diagnosis and treatment of HFpEF. The number of studies in this field is relatively small. Therefore, more high-quality studies are needed to explore the diagnostic and prognostic value of CMD and the potential role of CMD as a therapeutic target in patients with HFpEF.

The Role of Coronary Physiology Assessment in the Diagnosis and Treatment of Stable Angina. Dive Inside Recent Findings of Diffuse Coronary Disease Treatment

Coronary physiology is widely used to assess epicardial coronary lesions in patients with stable angina. Based on the available evidence, physiology plays a crucial role in diagnosing and treating patients. There have been invasive methods for determining cardiac physiology, such as fractional flow reserve and instantaneous wave-free ratio. Still, new non-invasive approaches provide extra anatomical information, such as fractional flow reserve computed tomography (FFR-CT) based on computed tomography and physiology based on angiography. Even though FFR-guided percutaneous coronary intervention (PCI) is clinically beneficial, one-third of patients retain suboptimal FFR after the procedure, associated with severe adverse events, rendering PCI in diffuse coronary artery disease questionable. Using the pullback pressure gradient (PPG), we can analyze the magnitude and extent of pressure losses; a lower value may indicate diffuse disease, while a high value with an abrupt curve may indicate focal disease. Since PCI is not the best option for treating diffuse coronary disease, current strategies focus on conservatively using medical therapy or bypass surgery. It has been demonstrated that patients with diffuse disease of the left anterior descending (LAD) are at a greater risk of developing occlusion of the left internal mammary artery graft than those with focal disease and that maximal medical therapy may be the most effective treatment for these patients.

[Precision medicine enhances personalized medicine in cardiology]

Personalized medicine and precision medicine, frequently used synonymously, shall be clearly differentiated. Accordingly, personalization in cardiac medicine is based on the clinical presentation of a patient, as well as his/her cardiovascular risk factors and comorbidities, electrocardiography, imaging, and biomarkers for myocardial load and ischemia. Personalization is based on large clinical trials with detailed subgroup analyses and is practiced on the basis of guidelines. Further in depth personalization is achieved by precision medicine, which is based on innovative imaging for myocardial structure, coronary morphology, and electrophysiology. From the clinical perspective, genome analyses are relevant for comparatively rare monogenetic cardiovascular diseases. While these as well as transcriptome and metabolome analyses play a significant role in cardiovascular research with great translation potential, they have not yet been broadly introduced in the diagnosis, prevention, and treatment of complex cardiovascular diseases. Furthermore, digital technologies have considerable potential in cardiovascular precision medicine. On the one hand, this is based on the frequency of the diseases with the availability of Big Data and, on the other hand, on the availability of bio-signals and sensors of those signals in cardiovascular diseases.

Coronary Vasomotor Dysfunction Is Associated With Cardiovascular Events in Patients With Nonobstructive Coronary Artery Disease

BACKGROUND

Coronary vasomotor dysfunction (CVDys) can be comprehensively classified on the basis of anatomy and functional mechanisms.

OBJECTIVES

The aim of this study was to evaluate the association between different CVDys phenotypes and outcomes in patients with angina and nonobstructive coronary artery disease (ANOCA).

METHODS

Patients with ANOCA who underwent coronary reactivity testing using an intracoronary Doppler guidewire to assess microvascular and epicardial coronary endothelium-dependent and endothelium-independent function were enrolled. Endothelium-dependent microvascular and epicardial coronary dysfunction were defined as a <50% change in coronary blood flow in response to intracoronary acetylcholine (Ach) infusion and a <-20% change in coronary artery diameter in response to Ach. Endothelium-independent microvascular and epicardial coronary dysfunction were defined as coronary flow reserve < 2.5 during adenosine-induced hyperemia and change in cross-sectional area in response to intracoronary nitroglycerin administration < 20%. Major adverse cardiac and cerebrovascular events (cardiovascular death, nonfatal MI, heart failure, stroke, and late revascularization) served as clinical outcomes.

RESULTS

Among the 1,196 patients with ANOCA, the prevalence of CVDys was 24.5% and 51.8% among those with endothelium-independent and endothelium-dependent microvascular dysfunction, respectively, and 47.4% and 25.4% among those with endothelium-independent and endothelium-dependent epicardial coronary dysfunction, respectively. During 6.3 years (Q1-Q3: 2.5-12.9 years) of follow-up, patients with endothelium-dependent microvascular dysfunction, endothelium-dependent epicardial coronary dysfunction, or endothelium-independent microvascular dysfunction showed significantly higher event rates compared with those without (19.5% vs 12.0% [P < 0.001], 19.7% vs 14.6% [P = 0.038] and 22.2% vs 13.8% [P = 0.001], respectively). Coronary flow reserve (HR: 0.757; 95% CI: 0.604-0.957) and percentage change in coronary blood flow in response to Ach infusion (HR: 0.998; 95% CI: 0.996-0.999) remained significant predictors of major adverse cardiac and cerebrovascular event after adjustment for conventional risk factors.

CONCLUSIONS

CVDys phenotype is differentially associated with worse outcomes, and endothelium-dependent and endothelium-independent microvascular function provide independent prognostic information in patients with ANOCA.

High Resting Coronary Flow Velocity by Echocardiography Is Associated With Worse Survival in Patients With Chronic Coronary Syndromes

BACKGROUND

Resting coronary flow velocity (CFV) in the mid-distal left anterior descending coronary artery can be easily assessed with transthoracic echocardiography. In this observational study, the authors sought to assess the relationship between resting CFV, CFV reserve (CFVR), and outcome in patients with chronic coronary syndromes.

METHODS AND RESULTS

In a prospective multicenter study design, the authors retrospectively analyzed 7576 patients (age, 66±11 years; 4312 men) with chronic coronary syndromes and left ventricular ejection fraction ≥50% referred for dipyridamole stress echocardiography. Recruitment (years 2003-2021) involved 7 accredited laboratories, with interobserver variability <10% for CFV measurement at study entry. Baseline peak diastolic CFV was obtained by pulsed-wave Doppler in the mid-distal left anterior descending coronary artery. CFVR (abnormal value ≤2.0) was assessed with dipyridamole. All-cause death was the only end point. The mean CFV of the left anterior descending coronary artery was 31±12 cm/s. The mean CFVR was 2.32±0.60. During a median follow-up of 5.9±4.3 years, 1121 (15%) patients died. At multivariable analysis, resting CFV ≥32 cm/s was identified by a receiver operating curve as the best cutoff and was independently associated with mortality (hazard ratio [HR], 1.24 [95% CI, 1.10-1.40]; P<0.0001) together with CFVR ≤2.0 (HR, 1.78 [95% CI, 1.57-2.02]; P<0.0001), age, diabetes, history of coronary surgery, and left ventricular ejection fraction. When both CFV and CFVR were considered, the mortality rate was highest in patients with resting CFV ≥32 cm/s and CFVR ≤2.0 and lowest in patients with resting CFV <32 cm/s and CFVR >2.0.

CONCLUSIONS

High resting CFV is associated with worse survival in patients with chronic coronary syndromes and left ventricular ejection fraction ≥50%. The value is independent and additive to CFVR. The combination of high resting CFV and low CFVR is associated with the worst survival.

Measuring Absolute Coronary Flow and Microvascular Resistance by Thermodilution: JACC Review Topic of the Week

Diagnosing coronary microvascular dysfunction remains challenging, primarily due to the lack of direct measurements of absolute coronary blood flow (Q) and microvascular resistance (Rμ). However, there has been recent progress with the development and validation of continuous intracoronary thermodilution, which offers a simplified and validated approach for clinical use. This technique enables direct quantification of Q and Rμ, leading to precise and accurate evaluation of the coronary microcirculation. To ensure consistent and reliable results, it is crucial to follow a standardized protocol when performing continuous intracoronary thermodilution measurements. This document aims to summarize the principles of thermodilution-derived absolute coronary flow measurements and propose a standardized method for conducting these assessments. The proposed standardization serves as a guide to ensure the best practice of the method, enhancing the clinical assessment of the coronary microcirculation.

Implementation of Microcirculation Examination in Clinical Practice-Insights from the Nationwide POL-MKW Registry

Background and Objectives: The assessment of coronary microcirculation may facilitate risk stratification and treatment adjustment. The aim of this study was to evaluate patients' clinical presentation and treatment following coronary microcirculation assessment, as well as factors associated with an abnormal coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) values. Materials and Results: This retrospective analysis included 223 patients gathered from the national registry of invasive coronary microvascular testing collected between 2018 and 2023. Results: The frequency of coronary microcirculatory assessments in Poland has steadily increased since 2018. Patients with impaired IMR (≥25) were less burdened with comorbidities. Patients with normal IMR underwent revascularisation attempts more frequently (11.9% vs. 29.8%, p = 0.003). After microcirculation testing, calcium channel blockers (CCBs) and angiotensin-converting enzyme inhibitors were added more often for patients with IMR and CFR abnormalities, respectively, as compared to control groups. Moreover, patients with coronary microvascular dysfunction (CMD, defined as CFR and/or IMR abnormality), regardless of treatment choice following microcirculation assessment, were provided with trimetazidine (23.2%) and dihydropyridine CCBs (26.4%) more frequently than those without CMD who were treated conservatively (6.8%) and by revascularisation (4.2% with p = 0.002 and 0% with p < 0.001, respectively). Multivariable analysis revealed no association between angina symptoms and IMR or CFR impairment. Conclusions: The frequency of coronary microcirculatory assessments in Poland has steadily increased. Angina symptoms were not associated with either IMR or CFR impairment. After microcirculation assessment, patients with impaired microcirculation, expressed as either low CFR, high IMR or both, received additional pharmacotherapy treatment more often.

Endovascular Repair of Zone 0 Ascending Aortic Aneurysm: A Review of Current Knowledge and Developing Technology

Aortic aneurysms represent the 15th leading cause of death in men and women over 55 years of age. Where historically these lesions were all addressed via an open approach, endovascular aortic repair has entirely altered the way that surgeons approach aortic lesions. Although it was initially employed for patients who were poor surgical candidates, endovascular repair is now standard for abdominal aortic aneurysms and aneurysms in the descending thoracic aorta. Open surgery remains the gold standard for management of ascending aneurysms, in part due to the limitations portended by the anatomy of the ascending aorta, although increasing evidence suggests that endovascular approaches are feasible and may sometimes be optimal for patient outcomes. Here, we present some of the anatomical and technical challenges of the endovascular approach to these "Zone 0" aneurysms, the associated complications, and the current state of device development.

Large lessons learned from small vessels: coronary microvascular dysfunction in HIV

PURPOSE OF REVIEW

Large cohort studies have consistently shown the presence of heart failure is approximately doubled among persons with HIV (PWH). Early studies of cardiovascular disease (CVD) in HIV were primarily focused on atherosclerotic burden, and we now have a greater understanding of large vessel disease in HIV. More recent studies have begun to inform us about small vessel disease, or coronary microvascular dysfunction (CMD), in HIV. CMD is recognized to be an important risk factor for adverse events related to heart failure, associated with cardiovascular mortality, and often presents without overt atherosclerotic disease.

RECENT FINDINGS

In this review, we highlight implications for CMD and relevant clinical studies in HIV. Inflammation and endothelial dysfunction, well known risk factors in HIV, may mediate the pathogenesis of CMD. Initial studies suggest that CMD worsens with ART initiation. Newer studies reveal CMD is present among well treated PWH without known CVD. In addition, myocardial flow reserve (MFR), a marker of CMD, is reduced in HIV similar to diabetes. There also appears to be sex differences, such that CMD is worse among women vs. men with HIV.

SUMMARY

Alterations in the coronary microvasculature may be an important mediator of subclinical myocardial dysfunction that deserves further clinical attention among PWH without known CVD.

Comparative predictors of mortality among patients referred for stress single-photon emission computed tomography versus positron emission tomography myocardial perfusion imaging

BACKGROUND

There is currently little information regarding the usage and comparative predictors of mortality among patients referred for single-photon emission computed tomography (SPECT) versus positron emission tomography (PET) myocardial perfusion imaging (MPI) within multimodality imaging laboratories.

METHODS

We compared the clinical characteristics and mortality outcomes among 15,718 patients referred for SPECT-MPI and 6202 patients referred for PET-MPI between 2008 and 2017.

RESULTS

Approximately two-thirds of MPI studies were performed using SPECT-MPI. The PET-MPI group was substantially older and included more patients with known coronary artery disease (CAD), hypertension, diabetes, and myocardial ischemia. The annualized mortality rate was also higher in the PET-MPI group, and this difference persisted after propensity matching 3615 SPECT-MPI and 3615 PET-MPI patients to have similar clinical profiles. Among the SPECT-MPI patients, the most potent predictor of mortality was exercise ability and performance, including consideration of patients' mode of stress testing and exercise duration. Among the PET-MPI patients, myocardial flow reserve (MFR) was the most potent predictor of mortality.

CONCLUSIONS

In our real-world setting, PET-MPI was more commonly employed among older patients with more cardiac risk factors than SPECT-MPI patients. The most potent predictors of mortality in our SPECT and PET-MPI groups were variables exclusive to each test: exercise ability/capacity for SPECT-MPI patients and MFR for PET-MPI patients.

Myocardial Interstitial Fibrosis in Hypertensive Heart Disease: From Mechanisms to Clinical Management

Hypertensive heart disease (HHD) can no longer be considered as the beneficial adaptive result of the hypertrophy of cardiomyocytes in response to pressure overload leading to the development of left ventricular hypertrophy. The current evidence indicates that in patients with HHD, pathological lesions in the myocardium lead to maladaptive structural remodeling and subsequent alterations in cardiac function, electrical activity, and perfusion, all contributing to poor outcomes. Diffuse myocardial interstitial fibrosis is probably the most critically involved lesion in these disorders. Therefore, in this review, we will focus on the histological characteristics, the mechanisms, and the clinical consequences of myocardial interstitial fibrosis in patients with HHD. In addition, we will consider the most useful tools for the noninvasive diagnosis of myocardial interstitial fibrosis in patients with HHD, as well as the most effective available therapeutic strategies to prevent its development or facilitate its regression in this patient population. Finally, we will issue a call to action for the need for more fundamental and clinical research on myocardial interstitial fibrosis in HHD.

Coronary physiology thresholds associated with microvascular obstruction in myocardial infarction

OBJECTIVES

To ascertain whether invasive assessment of coronary physiology soon after recanalisation of the culprit artery by primary percutaneous coronary intervention is associated with the development of microvascular obstruction by cardiac magnetic resonance in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

Between November 2020 and December 2021, 102 consecutive patients were prospectively enrolled in five tertiary centres in Italy. Coronary flow reserve (CFR) and index of microvascular resistance (IMR) were measured in the culprit vessel soon after successful primary percutaneous coronary intervention. Optimal cut-off points of IMR and CFR to predict the presence of microvascular obstruction were estimated, stratifying the population accordingly in four groups. A comparison with previously proposed stratification models was carried out.

RESULTS

IMR>31 units and CFR≤1.25 yielded the best accuracy. Patients with IMR>31 and CFR≤1.25 exhibited higher microvascular obstruction prevalence (83% vs 38%, p<0.001) and lower left ventricular ejection fraction (45±9% vs 52±9%, p=0.043) compared with those with IMR≤31 and CFR>1.25, and lower left ventricular ejection fraction compared with patients with CFR≤1.25 and IMR≤31 (45±9% vs 54±7%, p=0.025). Infarct size and area at risk were larger in the former, compared with other groups.

CONCLUSIONS

IMR and CFR are associated with the presence of microvascular obstruction in STEMI. Patients with an IMR>31 units and a CFR≤1.25 have higher prevalence of microvascular obstruction, lower left ventricular ejection fraction, larger infarct size and area at risk.

TRIAL REGISTRATION NUMBER

NCT04677257.

The clinical use of stress echocardiography in chronic coronary syndromes and beyond coronary artery disease: a clinical consensus statement from the European Association of Cardiovascular Imaging of the ESC

Since the 2009 publication of the stress echocardiography expert consensus of the European Association of Echocardiography, and after the 2016 advice of the American Society of Echocardiography-European Association of Cardiovascular Imaging for applications beyond coronary artery disease, new information has become available regarding stress echo. Until recently, the assessment of regional wall motion abnormality was the only universally practiced step of stress echo. In the state-of-the-art ABCDE protocol, regional wall motion abnormality remains the main step A, but at the same time, regional perfusion using ultrasound-contrast agents may be assessed. Diastolic function and pulmonary B-lines are assessed in step B; left ventricular contractile and preload reserve with volumetric echocardiography in step C; Doppler-based coronary flow velocity reserve in the left anterior descending coronary artery in step D; and ECG-based heart rate reserve in non-imaging step E. These five biomarkers converge, conceptually and methodologically, in the ABCDE protocol allowing comprehensive risk stratification of the vulnerable patient with chronic coronary syndromes. The present document summarizes current practice guidelines recommendations and training requirements and harmonizes the clinical guidelines of the European Society of Cardiology in many diverse cardiac conditions, from chronic coronary syndromes to valvular heart disease. The continuous refinement of imaging technology and the diffusion of ultrasound-contrast agents improve image quality, feasibility, and reader accuracy in assessing wall motion and perfusion, left ventricular volumes, and coronary flow velocity. Carotid imaging detects pre-obstructive atherosclerosis and improves risk prediction similarly to coronary atherosclerosis. The revolutionary impact of artificial intelligence on echocardiographic image acquisition and analysis makes stress echo more operator-independent and objective. Stress echo has unique features of low cost, versatility, and universal availability. It does not need ionizing radiation exposure and has near-zero carbon dioxide emissions. Stress echo is a convenient and sustainable choice for functional testing within and beyond coronary artery disease.

Assessing the Impact of Prolonged Averaging of Coronary Continuous Thermodilution Traces

Continuous Thermodilution is a novel method of quantifying coronary flow (Q) in mL/min. To account for variability of Q within the cardiac cycle, the trace is smoothened with a 2 s moving average filter. This can sometimes be ineffective due to significant heart rate variability, ventricular extrasystoles, and deep inspiration, resulting in a fluctuating temperature trace and ambiguity in the location of the "steady state". This study aims to assess whether a longer moving average filter would smoothen any fluctuations within the continuous thermodilution traces resulting in improved interpretability and reproducibility on a test-retest basis. Patients with ANOCA underwent repeat continuous thermodilution measurements. Analysis of traces were performed at averages of 10, 15, and 20 s to determine the maximum acceptable average. The maximum acceptable average was subsequently applied as a moving average filter and the traces were re-analysed to assess the practical consequences of a longer moving average. Reproducibility was then assessed and compared to a 2 s moving average. Of the averages tested, only 10 s met the criteria for acceptance. When the data was reanalysed with a 10 s moving average filter, there was no significant improvement in reproducibility, however, it resulted in a 12% diagnostic mismatch. Applying a longer moving average filter to continuous thermodilution data does not improve reproducibility. Furthermore, it results in a loss of fidelity on the traces, and a 12% diagnostic mismatch. Overall, current practice should be maintained.

Prevalence of Cardiovascular Disease and Rate of Major Adverse Cardiovascular Events in Severe Alpha-1 Antitrypsin Deficiency COPD

Aim

Alpha-1 antitrypsin deficiency is an autosomal co-dominant condition that predisposes individuals to early-onset emphysema. As with COPD, AATD-COPD is associated with pulmonary exacerbations, which impacts on overall mortality and quality of life. Though there is evidence that COPD is associated with a higher prevalence of cardiovascular disease and major adverse cardiovascular events (MACE), it is unclear if this is true for patients with AATD-COPD.

Methods

Prevalence of cardiovascular disease was determined in two separate severe AATD cohorts: AlphaNet, USA and the Birmingham AATD registry, UK. All patients had preexisting lung disease. Cardiovascular disease was defined as presence of any of the following: heart failure, ischaemic heart disease, atrial fibrillation, stroke, and myocardial infarction. A Cox proportional hazards model was used to assess the impact of prior cardiovascular disease and frequent exacerbator phenotype on risk of future MACE.

Results

Out of 3493 patients with severe AATD, 14.7% had prior cardiovascular disease, including stroke (2.3%), myocardial infarction (2.2%), and heart failure (2.5%). Frequent exacerbators were more likely to have preexisting cardiovascular disease compared with those with one or no exacerbations in the preceding year (63% vs 44.8%, p = 0.001). There was increased risk of future MACE in frequent exacerbators (HR 1.85, 95% CI 1.24 to 2.75), former and current smokers (HR 1.80, 95% CI 1.07 to 3.02, p = 0.026, and HR 4.04, 95% CI 1.44 to 11.32, p = 0.008, respectively), and those with prior cardiovascular disease (HR 3.81, 95% CI 2.60 to 5.58, p < 0.001).

Conclusion

In severe AATD-COPD, MACE are associated with an increased exacerbation frequency, previous cardiovascular disease, and a history of smoking.

Noninvasive transthoracic doppler flow velocity and invasive thermodilution to assess coronary flow reserve

Background

Coronary flow reserve (CFR) provides prognostication and coronary physiological information, including epicardial coronary stenosis and microvascular function. The relationship between stress transthoracic Doppler echocardiography (TDE)-derived coronary flow velocity reserve (CFRS-TDE) and thermodilution-derived coronary flow reserve (CFRthermo) before and after elective percutaneous coronary intervention (PCI) remains unclear.

Methods

This single-center prospective registry study evaluated patients who underwent fractional flow reserve (FFR)-guided elective PCI for left anterior descending artery (LAD) lesions with wire-based invasive physiological measurements and pre- and post-PCI stress TDE examinations.

Results

A total of 174 LAD lesions from 174 patients were included in the final analysis. A modest correlation was detected between the pre-PCI CFRS-TDE and the pre-PCI CFRthermo (r=0.383, P<0.001). The frequently used CFRS-TDE threshold of 2.0 corresponded to a pre-PCI CFRthermo of 2.18. Pre-PCI CFRS-TDE underestimated pre-PCI CFRthermo [1.89 (1.44-2.31) vs. 2.05 (1.38-2.93), P<0.001]. Both CFRS-TDE and CFRthermo increased significantly post-PCI [pre-PCI CFRS-TDE 1.89 vs. post-PCI CFRS-TDE 2.33, P<0.001; pre-PCI CFRthermo 2.05 (1.38-2.93) vs. post-PCI CFRthermo 2.59 (1.63-3.55), P<0.001]. In contrast, there was no significant relationship between changes in CFRS-TDE and changes in CFRthermo after PCI (r=0.008, P=0.915) or between post-PCI CFRS-TDE and post-PCI CFRthermo (r=0.054, P=0.482).

Conclusions

Pre-PCI CFRS-TDE and CFRthermo are modestly correlated, but post-PCI CFRS-TDE and CFRthermo have no correlation. CFRS-TDE and CFRthermo are not interchangeable, particularly post-PCI, suggesting that the two metrics represent different coronary physiologies after PCI.