Incorporating Inflammation Biomarker-Driven Multivariate Predictive Model for Coronary Microcirculatory Dysfunction in Acute Myocardial Infarction Following Emergency Percutaneous Coronary Intervention.

BACKGROUND: Despite patients with successful revascularization as evidenced by angiographic findings, inadequate clinical management of coronary microcirculatory dysfunction (CMD) may result in preventable adverse outcomes. Therefore, it is imperative to use a multimodal data­driven predictive model for the occurrence of CMD in patients with acute myocardial infarction (AMI) following emergency percutaneous coronary intervention (PCI). METHODS: A prospective case-control analysis was conducted on a cohort of 77 patients with AMI who underwent PCI. The most informative predictors were selected for the predictive model through the application of LASSO analysis and multi-factor logistic regression. The diagnosis of CMD is based on findings from cardiac magnetic resonance (CMR). RESULTS: Based on the findings from LASSO analysis and multi-factor logistic regression, variables including sex, neutrophil-to-lymphocyte ratio (NLR), Gensini score, and diabetes mellitus were identified as independent predictors for the development of CMD in AMI patients who underwent emergency PCI. The predictive model was evaluated using bootstrap self-sampling 500 times. The resulting predictive model demonstrated an AUC value of 0.897 (95% CI: 0.827-0.958). The calibration curves exhibited good concordance between the predictions generated by the model and the CMR analysis. Furthermore, decision curve analysis revealed that the predictive model provided valuable clinical benefit in predicting CMD. CONCLUSIONS: The multivariate predictive model, constructed using readily available clinical variables in patients with AMI who underwent PCI, demonstrates satisfactory predictability for identifying comorbid CMD, thereby facilitating the identification of high-risk patients.

Absolute coronary blood flow across different endotypes of ANOCA.

BACKGROUND: Intracoronary continuous thermodilution is a novel technique to quantify absolute true coronary flow and microvascular resistance. However, few data are available in patients with angina with non-obstructive coronary arteries (ANOCA). AIMS: This study aimed to investigate the diagnostic potential of hyperaemic absolute coronary flow (Qmax) and absolute microvascular resistance (Rµ,hyper) among different ANOCA endotypes, and to determine the correlation between continuous - and bolus - thermodilution indexes. METHODS: A total of 222 patients were scheduled for clinically indicated coronary function testing (CFT), of whom 120 patients were included in this analysis. These patients underwent CFT including acetylcholine (ACh) provocation testing and microvascular function assessment using both bolus and continuous thermodilution. RESULTS: CFT was negative (CFT-) in 32 (26.7%) patients. Endothelium-dependent dysfunction (ACh+) was present in 63 (52.5%) patients, and coronary microvascular dysfunction (CMD) identified at bolus thermodilution (CMD+) was present in 62 (51.7%) patients. Patients with a positive CFT (CFT+) showed significantly lower Qmax and higher Rµ,hyper values as compared to CFT-. Qmax was significantly lower in CMD+ versus CMD- patients (0.174 vs 0.222 L/min; p=0.04) but did not differ in patients with or without a positive ACh test (0.198 vs 0.219 L/min; p=0.86). CONCLUSIONS: The prevalence of a CFT+ is high in a selected ANOCA population. In our study, Qmax and Rµ,hyper were associated with a positive CFT. Qmax was associated with the presence of microvascular dysfunction but not with a positive acetylcholine test. The novel continuous thermodilution method can provide further insights into ANOCA endotypes.

Simplification of continuous intracoronary thermodilution.

BACKGROUND: Continuous intracoronary thermodilution with saline allows for the accurate measurement of volumetric blood flow (Q) and absolute microvascular resistance (Rµ). However, this requires repositioning of the temperature sensor by the operator to measure the entry temperature of the saline infusate, denoted as Ti. AIMS: We evaluated whether Ti could be predicted based on known parameters without compromising the accuracy of calculated Q. This would significantly simplify the technique and render it completely operator independent. METHODS: In a derivation cohort of 371 patients with Q measured both at rest and during hyperaemia, multivariate linear regression was used to derive an equation for the prediction of Ti. Agreement between standard Q (calculated with measured Ti) and simplified Q (calculated with predicted Ti) was assessed in a validation cohort of 120 patients that underwent repeat Q measurements. The accuracy of simplified Q was assessed in a second validation cohort of 23 patients with [15O]H2O positron emission tomography (PET)-derived Q measurements. RESULTS: Simplified Q exhibited strong agreement with standard Q (r=0.94, confidence interval [CI]: 0.93-0.95; intraclass correlation coefficient [ICC] 0.94, CI: 0.92-0.95; both p<0.001). Simplified Q exhibited excellent agreement with PET-derived Q (r=0.86, CI: 0.75-0.92; ICC=0.84, CI: 0.72-0.91; both p<0.001). Compared with standard Q, there were no statistically significant differences between correlation coefficients (p=0.29) or standard deviations of absolute differences with PET-derived Q (p=0.85). CONCLUSIONS: Predicting Ti resulted in an excellent agreement with measured Ti for the assessment of coronary blood flow. It significantly simplifies continuous intracoronary thermodilution and renders absolute coronary flow measurements completely operator independent.

Absolute coronary flow and microvascular resistance before and after transcatheter aortic valve implantation.

BACKGROUND: Severe aortic stenosis (AS) is associated with left ventricular (LV) remodelling, likely causing alterations in coronary blood flow and microvascular resistance. AIMS: We aimed to evaluate changes in absolute coronary flow and microvascular resistance in patients with AS undergoing transcatheter aortic valve implantation (TAVI). METHODS: Consecutive patients with AS undergoing TAVI with non-obstructive coronary artery disease in the left anterior descending artery (LAD) were included. Absolute coronary flow (Q) and microvascular resistance (Rµ) were measured in the LAD using continuous intracoronary thermodilution at rest and during hyperaemia before and after TAVI, and at 6-month follow-up. Total myocardial mass and LAD-specific mass were quantified by echocardiography and cardiac computed tomography. Regional myocardial perfusion (QN) was calculated by dividing absolute flow by the subtended myocardial mass. RESULTS: In 51 patients, Q and R were measured at rest and during hyperaemia before and after TAVI; in 20 (39%) patients, measurements were also obtained 6 months after TAVI. No changes occurred in resting and hyperaemic flow and resistance before and after TAVI nor after 6 months. However, at 6-month follow-up, a notable reverse LV remodelling resulted in a significant increase in hyperaemic perfusion (QN,hyper: 0.86 [interquartile range {IQR} 0.691.06] vs 1.20 [IQR 0.99-1.32] mL/min/g; p=0.008; pre-TAVI and follow-up, respectively) but not in resting perfusion (QN,rest: 0.34 [IQR 0.30-0.48] vs 0.47 [IQR 0.36-0.67] mL/min/g; p=0.06). CONCLUSIONS: Immediately after TAVI, no changes occurred in absolute coronary flow or coronary flow reserve. Over time, the remodelling of the left ventricle is associated with increased hyperaemic perfusion.

Non-alcoholic fatty liver disease is associated with coronary flow reserve impairment: A pilot meta-analysis.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is estimated to affect approximately 25% of the global population. Both, coronary artery disease and NAFLD are linked to underlying insulin resistance and inflammation as drivers of the disease. Coronary flow reserve parameters, including coronary flow reserve velocity (CFRV), baseline diastolic peak flow velocity (DPFV), and hyperemic DPFV, are noninvasive markers of coronary microvascular circulation. The existing literature contains conflicting findings regarding these parameters in NAFLD patients. METHODS: A comprehensive systematic search was conducted on major electronic databases from inception until May 8, 2024, to identify relevant studies. We pooled the standardized mean differences (SMD) with 95% confidence intervals (CI) using the inverse-variance random-effects model. Statistical significance was set at P < .05. RESULTS: Four studies with 1139 participants (226 with NAFLD and 913 as controls) were included. NAFLD was associated with a significantly lower CFRV (SMD: -0.77; 95% CI: -1.19, -0.36; P < .0002) and hyperemic DPFV (SMD: -0.73; 95% CI: -1.03, -0.44; P < .00001) than the controls. NAFLD demonstrated a statistically insignificant trend toward a reduction in baseline DPFV (SMD: -0.09; 95% CI: -0.38, 0.19; P = .52) compared to healthy controls. CONCLUSION: Patients with NAFLD are at a higher risk of coronary microvascular dysfunction, as demonstrated by reduced CFRV and hyperemic DPFV. The presence of abnormal coronary flow reserve in patients with NAFLD provides insights into the higher rates of cardiovascular disease in these patients. Early aggressive targeted interventions for impaired coronary flow reserve in subjects with NAFLD may lead to improvement in clinical outcomes.

Diagnostic Yield and Clinical Utility of Coronary Angiography Versus Coronary Function Testing in Women With Angina and Nonobstructive Coronary Arteries.

BACKGROUND: Approximately 50% of women referred for invasive coronary angiography have angina and nonobstructive coronary arteries, which includes coronary microvascular dysfunction, vasospastic angina, and other vasomotor disorders. We sought to determine the real-world diagnostic yield of invasive coronary angiography and coronary function testing in women with angina and nonobstructive coronary arteries. METHODS AND RESULTS: From 2018 to 2023, we enrolled 198 women who underwent either coronary angiography (CA) alone (n=99) or coronary function testing (CFT; n=99). Mean±SD age was 62±10 years (CA alone) compared with 57±10 years (CFT). Coronary angiography was interpreted as nonobstructive coronary artery disease more frequently after CA alone (79% versus 52%). Of the women who underwent CFT, 82% (N=81) were found to have vasomotor disorders, including coronary microvascular dysfunction (27%), vasospastic angina (32%), mixed coronary microvascular dysfunction/vasospastic angina (16%), endothelial dysfunction (10%; without spasm), elevated resting flow (2%), or symptomatic myocardial bridging (4%). Compared with women undergoing CA alone, medications were changed more frequently after CFT at 24 hours (41% versus 65%; P=0.001) and between 24 hours and 30 days (30% versus 44%; P=0.04) with intensification of antianginal therapy (79% versus 92%; P<0.0001) and increased use of calcium channel blockers (36% versus 63%; P<0.0001). CONCLUSIONS: Our findings demonstrate that women presenting with suspected ischemic heart disease undergoing CA alone only received an anatomic diagnosis, whereas >80% of women undergoing CFT received a specific diagnosis of a coronary vasomotor disorder and greater intensification of antianginal therapy.

Advances in the Computational Assessment of Disturbed Coronary Flow and Wall Shear Stress: A Contemporary Review.

Coronary artery blood flow is influenced by various factors including vessel geometry, hemodynamic conditions, timing in the cardiac cycle, and rheological conditions. Multiple patterns of disturbed coronary flow may occur when blood flow separates from the laminar plane, associated with inefficient blood transit, and pathological processes modulated by the vascular endothelium in response to abnormal wall shear stress. Current simulation techniques, including computational fluid dynamics and fluid-structure interaction, can provide substantial detail on disturbed coronary flow and have advanced the contemporary understanding of the natural history of coronary disease. However, the clinical application of these techniques has been limited to hemodynamic assessment of coronary disease severity, with the potential to refine the assessment and management of coronary disease. Improved computational efficiency and large clinical trials are required to provide an incremental clinical benefit of these techniques beyond existing tools. This contemporary review is a clinically relevant overview of the disturbed coronary flow and its associated pathological consequences. The contemporary methods to assess disturbed flow are reviewed, including clinical applications of these techniques. Current limitations and future opportunities in the field are also discussed.

Pathogenesis, Assessment, and Treatment of Coronary Microcirculation Dysfunction. / Patogênese, Avaliação e Tratamento da Disfunção da Microcirculação Coronariana.

Cardiovascular disease is the predominant cause of mortality on a global scale. Research indicates that women exhibit a greater likelihood of presenting with non-obstructive coronary artery disease (CAD) when experiencing symptoms of myocardial ischemia in comparison to men. Additionally, women tend to experience a higher burden of symptoms relative to men, and despite the presence of ischemic heart disease, they are frequently reassured erroneously due to the absence of obstructive CAD. In cases of ischemic heart disease accompanied by symptoms of myocardial ischemia but lacking obstructive CAD, it is imperative to consider coronary microvascular dysfunction as a potential underlying cause. Coronary microvascular dysfunction, characterized by impaired coronary flow reserve resulting from functional and/or structural abnormalities in the microcirculation, is linked to adverse cardiovascular outcomes. Lifestyle modifications and the use of anti-atherosclerotic and anti-anginal medications may offer potential benefits, although further clinical trials are necessary to inform treatment strategies. This review aims to explore the prevalence, underlying mechanisms, diagnostic approaches, and therapeutic interventions for coronary microvascular dysfunction.

A doença cardiovascular é a causa predominante de mortalidade em escala global. A pesquisa indica que as mulheres, em comparação aos homens, apresentam maior probabilidade de apresentar doença arterial coronariana (DAC) não obstrutiva quando têm sintomas de isquemia miocárdica. Além disso, as mulheres tendem a apresentar uma maior carga de sintomas em relação aos homens e, apesar da presença de doença cardíaca isquêmica, são frequentemente tranquilizadas erroneamente devido à ausência de DAC obstrutiva. Nos casos de cardiopatia isquêmica acompanhada de sintomas de isquemia miocárdica, mas sem DAC obstrutiva, é imperativo considerar a disfunção microvascular coronariana como uma potencial causa subjacente. A disfunção microvascular coronariana, caracterizada por reserva de fluxo coronariano prejudicada resultante de anormalidades funcionais e/ou estruturais na microcirculação, está associada a desfechos cardiovasculares adversos. Modificações no estilo de vida e o uso de medicamentos antiateroscleróticos e antianginosos podem oferecer benefícios potenciais, embora sejam necessários mais ensaios clínicos para informar estratégias de tratamento. Esta revisão tem como objetivo explorar a prevalência, mecanismos subjacentes, abordagens diagnósticas e intervenções terapêuticas para disfunção microvascular coronariana.

Developments and Controversies in Invasive Diagnosis of Coronary Microvascular Dysfunction in Angina With Nonobstructive Coronary Arteries.

Approximately half of all coronary angiograms performed for angina do not show obstructive coronary artery disease, and many of these patients have coronary microvascular dysfunction (CMD). Invasive testing for CMD has increased with the advent and wider availability of thermodilution systems. We review CMD pathophysiology and invasive diagnostic testing using the Doppler and thermodilution systems. We report the results of a PubMed search of invasive microvascular testing and discuss limitations of current diagnostic algorithms in the diagnosis of CMD, including controversies regarding the optimal cutoff value for abnormal coronary flow reserve, use of microvascular resistance indices, and options for increasing sensitivity of testing.

Endocan may predict the presence of coronary slow flow and coronary artery disease.

OBJECTIVE: Coronary artery disease (CAD) is frequent, but coronary slow flow (CSF) is a less common cardiovascular disease with a significant risk of mortality and morbidity. Endocan is a proinflammatory glycopeptide that has been investigated in cardiovascular diseases as well as some inflammatory diseases in recent years. We planned to compare the levels of endocan in both CAD and CSF in a similar population and examine the relationship of endocan with additional clinical variables. MATERIALS AND METHODS: In the trial, we included 169 consecutive subjects having a coronary angiography indication. According to the results of coronary angiography, 58 people were included in the CAD group, 52 were in the CSF group, and 59 people were in the control group. The control group includes those who did not have any lesions in their epicardial coronary arteries. Thrombolysis in myocardial infarction (TIMI)-frame counts (TFC) were calculated for all patients. RESULTS: Notably, 2.6% of the population in our study had CSF. Both the CAD (555±223 pg/mL) and CSF (559±234 pg/mL) groups had higher endocan levels than the control group (331±252 pg/mL) (p<0.001). There were similar endocan levels between the CAD and CSF groups. Endocan levels were shown to be favorably associated with mean TFC (r=0.267; p0.001). Serum endocan levels (particularly those above 450 pg/mL) and the presence of hyperlipidemia were the most important predictors of both CAD and CSF. CONCLUSION: Endocan levels are higher in CAD and CSF patients than in those with normal coronary arteries.

Development and validation of a machine learning model to predict myocardial blood flow and clinical outcomes from patients' electrocardiograms.

We develop a machine learning (ML) model using electrocardiography (ECG) to predict myocardial blood flow reserve (MFR) and assess its prognostic value for major adverse cardiovascular events (MACEs). Using 3,639 ECG-positron emission tomography (PET) and 17,649 ECG-single-photon emission computed tomography (SPECT) data pairs, the ML model is trained with a swarm intelligence approach and support vector regression (SVR). The model achieves a receiver-operator curve (ROC) area under the curve (AUC) of 0.83, with a sensitivity and specificity of 0.75. An ECG-MFR value below 2 is significantly associated with MACE, with hazard ratios (HRs) of 3.85 and 3.70 in the discovery and validation phases, respectively. The model's C-statistic is 0.76, with a net reclassification improvement (NRI) of 0.35. Validated in an independent cohort, the ML model using ECG data offers superior MACE prediction compared to baseline clinical models, highlighting its potential for risk stratification in patients with coronary artery disease (CAD) using the accessible 12-lead ECG.

Correlation between serum levels of circ_0001879 and circ_0004104, coronary microcirculation disorders and prognosis after percutaneous coronary intervention (PCI) in patients with stable coronary heart disease.

OBJECTIVE: This study aims to elucidate the association between serum levels of circular RNAs circ_0001879 and circ_0004104 and the occurrence of coronary microcirculation disorders along with post-PCI prognosis in individuals with stable coronary heart disease. METHODS: A cohort of 92 patients diagnosed with stable coronary heart disease and subjected to PCI between June 2020 and June 2022 at our institution was assembled. Patients were categorized into an exposed group (n = 60) and a non-exposed group (n = 32), predicated on the coronary angiography-derived microcirculation resistance index (caIMR). RESULTS: Comparative analysis revealed significantly elevated levels of circ_0001879 and circ_0004104 in the serum of the exposed group compared to the non-exposed group, with statistical significance (P < 0.05). Post-PCI, both caFFR and caIMR values demonstrated a marked increase in comparison to pre-surgical measurements within both groups, with the exposed group exhibiting lower indices post-surgery relative to the non-exposed group, indicative of superior microcirculatory outcomes (P < 0.05). Furthermore, serum levels of circ_0001879 and circ_0004104 were inversely correlated with favorable prognosis, with lower levels observed in patients with positive outcomes (P < 0.05). The predictive accuracy for poor prognosis, as indicated by the area under the curve (AUC), was enhanced when circ_0001879 and circ_0004104 were considered in tandem (AUC = 0.934), surpassing the predictive power of individual assessments (Z combination vs circ_0001879 = 2.439, Z combination vs circ_0004104 = 2.317, P < 0.05). CONCLUSION: Elevated serum levels of circ_0001879 and circ_0004104 are observed in stable coronary heart disease patients and are significantly associated with the presence of coronary microcirculation disorders and post-PCI prognosis, underscoring their potential as prognostic biomarkers.

The role of myocardial blood volume in the pathophysiology of angina with non-obstructed coronary arteries: The MICORDIS study.

BACKGROUND: Angina with Non-Obstructed Coronary Arteries (ANOCA) involves abnormal vasomotor responses. While reduced coronary flow is an established contributor to myocardial hypoxia, myocardial blood volume (MBV) independently regulates myocardial oxygen uptake but its role in ANOCA remains unclear. OBJECTIVES: We hypothesized that reduced MBV contributes to ANOCA, and associates with insulin resistance in ANOCA. METHODS: MBV in ANOCA patients was compared to age- and sex-matched healthy controls. ANOCA patients underwent coronary angiography with invasive coronary function testing (CFT) to identify vasospasm and coronary microvascular dysfunction. In all subjects MBV was quantified at baseline, during hyperinsulinemia and during dobutamine-induced stress using myocardial contrast echocardiography (MCE). The hyperinsulinemic-euglycemic clamp was used to assess insulin resistance. RESULTS: Twenty-eight ANOCA patients (21% men, 56.8 ± 8.6 years) and 28 healthy controls (21% men, 56.5 ± 7.0 years) were included. During CFT 11% of patients showed epicardial vasospasm, 39% microvascular vasospasm, 25% coronary microvascular dysfunction, and 11% of patients had a negative CFT. ANOCA patients had significant lower insulin-sensitivity (p < 0.01). During MCE, ANOCA patients showed a significantly lower MBV at baseline (0.388 vs 0.438 mL/mL, p = 0.04), during hyperinsulinemia (0.395 vs 0.447 mL/mL, p = 0.02), and during dobutamine-induced stress (0.401 vs 0.476 mL/mL, p = 0.030). CONCLUSIONS: In ANOCA patients MBV is diminished at baseline, during hyperinsulinemia and dobutamine-induced stress in the absence of differences in microvascular recruitment. These findings support the presence of capillary rarefaction in ANOCA patients. ANOCA patients showed metabolic insulin resistance, but insulin did not acutely alter myocardial perfusion.

Reproducibility of a single-volume dynamic CT myocardial blood flow measurement technique: validation in a swine model.

BACKGROUND: We prospectively assessed the reproducibility of a novel low-dose single-volume dynamic computed tomography (CT) myocardial blood flow measurement technique. METHODS: Thirty-four pairs of measurements were made under rest and stress conditions in 13 swine (54.3 ± 12.3 kg). One or two acquisition pairs were acquired in each animal with a 10-min delay between each pair. Contrast (370 mgI/mL; 0.5 mL/kg) and a diluted contrast/saline chaser (0.5 mL/kg; 30:70 contrast/saline) were injected peripherally at 5 mL/s, followed by bolus tracking and acquisition of a single volume scan (100 kVp; 200 mA) with a 320-slice CT scanner. Bolus tracking and single volume scan data were used to derive perfusion in mL/min/g using a first-pass analysis model; the coronary perfusion territories of the left anterior descending (LAD), left circumflex (LCx), and right coronary artery (RCA) were automatically assigned using a previously validated minimum-cost path technique. The reproducibility of CT myocardial perfusion measurement within the LAD, LCx, RCA, and the whole myocardium was assessed via regression analysis. The average CT dose index (CTDI) of perfusion measurement was recorded. RESULTS: The repeated first (Pmyo1) and second (Pmyo2) single-volume CT perfusion measurements were related by Pmyo2 = 1.01Pmyo1 - 0.03(ρ = 0.96; RMSE = 0.08 mL/min/g; RMSE = 0.07 mL/min/g) for the whole myocardium, and by Preg2 = 0.86Preg1 + 0.13(ρ = 0.87; RMSE = 0.31 mL/min/g; RMSE = 0.29 mL/min/g) for the LAD, LCx, and RCA perfusion territories. The average CTDI of the single-volume CT perfusion measurement was 10.5 mGy. CONCLUSION: The single-volume CT blood flow measurement technique provides reproducible low-dose myocardial perfusion measurement using only bolus tracking data and a single whole-heart volume scan. RELEVANCE STATEMENT: The single-volume CT blood flow measurement technique is a noninvasive tool that reproducibly measures myocardial perfusion and provides coronary CT angiograms, allowing for simultaneous anatomic-physiologic assessment of myocardial ischemia. KEY POINTS: A low-dose single-volume dynamic CT myocardial blood flow measurement technique is reproducible. Motion misregistration artifacts are eliminated using a single-volume CT perfusion technique. This technique enables combined anatomic-physiologic assessment of coronary artery disease.

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.

Association between optical coherence tomography-defined culprit morphologies and changes in hyperemic coronary flow after elective stenting assessed by transthoracic Doppler echocardiography.

BACKGROUND: Stress-transthoracic Doppler echocardiography (S-TDE) provides a noninvasive assessment of coronary flow parameters in the left anterior descending artery (LAD). However, the association between morphological characteristics and coronary flow changes after elective percutaneous coronary intervention (PCI) remains unclear. We aimed to evaluate the relationships between periprocedural coronary flow changes observed on S-TDE and lesion-specific plaque characteristics obtained by optical coherence tomography (OCT) in the interrogated vessels in patients with chronic coronary syndrome (CCS). METHODS AND RESULTS: Patients with CCS who underwent pre- and post-PCI S-TDE and elective fractional flow reserve (FFR)-guided PCI under OCT guidance for de novo single LAD lesions were included. S-TDE-derived hyperemic diastolic peak flow velocity (hDPV) was used as a surrogate for coronary flow. Lesions were categorized into two groups based on the %hDPV increase or decrease. The baseline clinical, physiological, and OCT findings were compared between the groups. In total, 103 LAD lesions were studied in 103 patients. After PCI, hDPV significantly increased from 55.6 cm/s to 69.5 cm/s (P<0.01), with a median %hDPV increase of 27.2 (6.32-59.1) %, while %hDPV decreased in 20 (19.4%) patients. The FFR improved in all patients. On OCT, layered plaques were more frequently present in the culprit vessels in the %hDPV-decrease group than in the %hDPV-increase group (85.0% vs. 50.6%, P = 0.01). Multivariable logistic regression analysis showed that the presence of layered plaques and high pre-PCI hDPV were independent predictors of %hDPV decrease. CONCLUSIONS: In patients who underwent successful uncomplicated elective PCI for de novo single LAD lesions, the presence of layered plaques was independently associated with hyperemic coronary flow decrease as assessed by S-TDE.

Prognostic Value of Coronary Microvascular Dysfunction Assessed by Coronary Angiography-Derived Index of Microcirculatory Resistance in Patients With ST-Segment Elevation Myocardial Infarction.

BACKGROUND: CaIMR is proposed as a novel angiographic index designed to assess microcirculation without the need for pressure wires or hyperemic agents. We aimed to investigate the impact of caIMR on predicting clinical outcomes in STEMI patients. METHODS: One hundred and forty patients with STEMI who received PCI in Putuo Hospital of Shanghai from October 2021 to September 2022 were categorized into CMD and non-CMD groups according to the caIMR value. The baseline information, patient-related examinations, and the occurrence of MACE at the 12-month follow-up were collected to investigate risk factors in patients with STEMI. RESULTS: We divided 140 patients with STEMI enrolled into two groups according to caIMR results, including 61 patients diagnosed with CMD and 79 patients diagnosed with non-CMD. A total of 21 MACE occurred during the 1 year of follow-up. Compared with non-CMD group, patients with CMD showed a significantly higher risk of MACE. A multivariate Cox regression model was conducted for the patients, and it was found thatcaIMR was a significant predictor of prognosis in STEMI patients (HR: 8.921). Patients with CMD were divided into culprit vascular CMD and non-culprit vascular CMD, and the result found that culprit vascular CMD was associated with the incidence of MACE (OR: 4.75) and heart failure (OR: 7.50). CONCLUSION: CaIMR is a strong predictor of clinical outcomes and can provide an objective risk stratification for patients with STEMI. There is a strong correlation among leukocyte index, the use of furosemide, Killips classification, and clinical outcomes.