Coronary Artery Flow Research Articles

Assessment of TIMI frame count pre- and post- intracoronary acetylcholine administration in patients with angina and non-obstructive coronary arteries (ANOCA)

Abstract Background Patients with Angina and unobstructed coronary arteries (ANOCA) represent a diagnostic challenge. Current ESC guidelines on the management of patients with chronic coronary syndrome recommend intracoronary spasm testing and coronary spasm represents a frequent diagnosis in such patients. Previous studies have shown that coronary artery flow assessments during acetylcholine testing frequently show non-uniform results. Purpose The aim of the present study was to assess changes in TIMI Frame Count (a quantitative method for the assessment of coronary artery flow) pre- and post- intracoronary acetylcholine testing in patients with ANOCA. Methods From 2007 to 2018, a total of 141 consecutive patients (51.8% female, mean age 61 ± 13.2 years) were included in the study. Among them, 63 patients (45%) presented with myocardial infarction with unobstructed coronary arteries, while 78 patients (55%) presented with stable angina and unobstructed coronaries. Following diagnostic angiography, all patients underwent intracoronary acetylcholine testing using a standardized protocol. TIMI frame count (TFC) was measured both for LAD and LCX before and after ACh injection, and post nitroglycerine injection. All counted frames were adjusted to a frame rate of 30 frames per second (fps). Furthermore, TFC of the LAD was divided by 1.7 to obtain the corrected TFC (cTFC). Results Of all 141 patients, coronary spasm was found in 98 patients (70%) during ACh testing (44% epicardial and 56% microvascular spasm). In the spasm cohort, the median cTFC in the LAD pre-ACh was 21.8 fps (quartiles: 16.3 – 30.0), decreased to 12.9 fps (8.8 - 19.2) post-ACh, and increased to 15.9 fps (10.6 - 21.3) post-nitro. The difference in the LAD between pre-ACh and post-ACh was statistically significant (p < 0.001). In the LCX the median TFC was 26.5 fps (15.0 – 40.5) pre-ACh, decreased to 16.0 fps (11.5 - 28.5) post-ACh and reached 24.0 fps (15.5 - 33.3) post-nitro. Again, this reduction from pre-ACh to post-ACh was statistically significant (p < 0.001). In the negative spasm cohort median cTFC for the LAD was 22.9 fps (16.0 – 18.2) pre-Ach, 15.3 fps (9.4 – 24.7) post-ACh and 15.8 fps (10.6 - 24.7) post-nitro, TFC for LCX was 24.0 fps (18.0 - 36.0) pre-ACh, 18.0 fps (12.0 – 33.0) post-ACh and 24.0 fps (12.0 – 34.0) post-nitro. The change in cTFC/TFC pre-ACh compared to post-ACh was statistically significant for both coronary arteries (LAD, p=0.012; LCX p=0.005, Table 1). Interestingly, in the spasm cohort 22% of LAD and 32% of LCX vessels showed higher TFC post-ACh compared to pre-ACh (Figure 1). Conclusions In patients with ANOCA and coronary spasm assessment of TIMI frame count reveals a hetereogeneous response. The majority of cases shows a decrease in TFC suggesting an increase in flow despite coronary spasm. This interesting finding allows speculations about the presence of coronary shunts.Figure 1

Pretreatment with dual antiplatelet therapy in acute myocardial infarction

Abstract Background Combined antithrombotic therapy prevents thrombus progression and its components embolization, and thus, it has an essential role in coronary microcirculation (re)perfusion in acute myocardial infarction (AMI). Pretreatment with P2Y12 inhibitors, on top of aspirin, before primary angioplasty has not been satisfactorily studied in STEMI. Purpose To investigate the impact of combined antiplatelet therapy on-treatment on the outcome of patients with STEMI. Methods Patients who suffered STEMI during the 7 years (1/2016-12/2022) were included. The analysis is based on population data from the National Health Information System (NHIS). Information on AMIs from the Intervention Module of the Registry of Cardiovascular Operations and Interventions was combined with prescription data from the Registry of Reimbursed Health Services 6 months before MI and identification of deceased patients from the Registry of Death Records. Data from the NHIS covers almost 100% of all cases in the population. Standard descriptive statistics and test were applied in the analysis. Multivariate logistic regression adjusted for clinical and procedural characteristics was adopted to analyze the influence of pretreatment on the risk of 1) out-of-hospital cardiac arrest (OHCA), 2) clinical condition at admission – need of mechanical ventilation and circulatory instability (Killip III,IV), 3) initial TIMI flow through the infarct-related coronary artery (IRA ), and 4) short term mortality. Results The study sample consisted of data from 40,383 STEMIs of which 1,601 patients were on dual antiplatelet therapy (DAPT) with aspirin plus iP2Y12 lasting 1 to 6 months before the event occurred. Patients on chronic oral anticoagulation (N 2101) were excluded. Patients on DAPT versus those without antiplatelet therapy or on aspirin at a daily dose of 100 mg were older, had higher comorbidity rates, and were at higher risk of mortality (Table). The multivariate logistic regression analysis showed that patients on DAPT at the time of MI onset and lasting for at least one month had a higher likelihood of preserved perfusion through the IRA (Odds ratio and 95% Confidence interval, OR (95% CI) 1. 193 (1.074; 1.326), p=0.001). However, the DAPT pretreatment did not reduce the risk of OHCA, the need for mechanical ventilation, or initial circulatory destabilization. It did not positively affect the prognosis of the patients (Figure ). Conclusion The significant benefit of the DAPT pretreatment on the preservation of infarct-related coronary artery flow did not translate into a positive effect on the prognosis of STEMI patients.

Impact of systolic coronary flow reversal in patients with aortic stenosis: assessment with transthoracic echocardiography

Abstract Background In patients with aortic stenosis (AS), increased systolic wall stress due to increased afterload reduces systolic coronary flow, often leading to systolic coronary flow reversal (SFR) in epicardial coronary arteries. Purpose We used transthoracic echocardiography (TTE) to evaluate severity of AS, left ventricular function, and coronary flow, and investigated echocardiographic indicators associated with SFR. Methods We prospectively evaluated consecutively presenting patients who visited our valvular heart disease outpatient clinic or were admitted to our hospital for investigation of AS (July 2023 to February 2024). Based on ESC guidelines, severity of AS and the left ventricular function were assessed with TTE. At the same time, TTE was used to measure distal left anterior descending coronary artery flow. SFR was defined as the presence of a reversal coronary flow component in systole. Based on the presence or absence of SFR in coronary flow measurements, patients were classified into SFR+ or SFR− groups. The inclusion criteria were AS of moderate or greater severity, and the exclusion criteria were known coronary stenosis and the inability to assess coronary flow. Results Enrolled 28 patients were classified into SFR+ (7 patients) and SFR − (21 patients) groups. Comparing baseline characteristics between the SFR+ and SFR− groups, although there were no significant differences in left ventricular indicators such as left ventricular mass index, left ventricular ejection fraction, stroke volume index, and E/e’ between the two groups, left ventricular global longitudinal strain was significantly lower in the SFR+ group (12.0±3.1%, 14.9±3.0%, p=0.026) (Table 1). Regarding indexes of AS assessment, aortic valve peak velocity and aortic valve mean pressure gradient values were significantly higher in the SFR+ group than in the SFR − group ([475±68 cm/s, 379±55 cm/s, p<0.001] and [56.2±16.5 mm Hg, 34.8±10.5 mm Hg, p<0.001], respectively) (Table 1). Representative cases show Figure 1. Conclusion The presence of SFR in patients with AS assessed using TTE may be a simple echocardiographic index that may be associated with potential decline in left ventricular function and progression of AS.

Spontaneous Coronary Artery Dissection “Storm” in Post Partum: a case report

Abstract Background Spontaneous coronary artery dissection remains a rare form of acute coronary syndrome in young women. It is not always easy to diagnose and its management can be complex, particularly in the case of severe forms. Case summary A 29-year-old mahorese woman presented with non-ST elevation acute coronary syndrome (NSTE-ACS) 72 hours after vaginal delivery of an uncomplicated twin pregnancy. Coronary angiography revealed a spontaneous coronary artery dissection (SCAD) of the left anterior descending artery (LAD) treated medically. At day 4, urgent coronary angiography was performed due to recurrent acute coronary syndrome (ACS) with unfavourable evolution on LAD SCAD with worsening flow and appearance of right coronary artery (RCA) dissection. Percutaneous coronary intervention (PCI) was performed with drug eluting stent (DES) implantation in LAD under optical coherence tomography (OCT) guidance. At day 6, the patient suffered from inferior STEMI due to extension of the RCA SCAD with occlusion of the posterior descending artery (PDA). Once again, under OCT guidance, PCI was performed in RCA with implantation of 4 DES. At day 8, the patient presented with an intra hospital cardiac arrest by electromechanical dissociation. Urgent coronary angiography revealed a diffuse extension of the SCAD to the circumflex artery and the left main trunk (LM). Rescue PCI of the LM was performed under OCT guidance and a femoro-femoral extracorporeal life support (ECLS) was implanted because of haemodynamic instability. With no hope of left ventricular ejection fraction (LVEF) recovery, the patient eventually benefited from a heart transplant 12 days after the first ACS with excellent evolution. Discussion Although the majority of SCAD have a favourable outcome with spontaneous healing, it is important to keep in mind that certain severe forms exist and could require specific management as PCI under OCT guidance and potential transfer to surgical centres where heart transplants and mechanical circulatory support are available.

Native Sinus Hemodynamics and Thrombosis in Transcatheter Heart Valve: Effect of Implant Depth and Coronary Flow.

This study aimed to investigate the hemodynamic and anatomic factors associated with sinus thrombosis following transcatheter aortic valve replacement (TAVR), integrating invivo patient data analysis and invitro experiments. Postprocedural, 4-dimensional, multiphase computed tomography data from 211 patients enrolled in the ADAPT-TAVR (Anticoagulation Versus Dual Antiplatelet Therapy for Prevention of Leaflet Thrombosis and Cerebral Embolization After Transcatheter Aortic Valve Replacement) study were analyzed. The prevalence of native sinus thrombosis was examined in relation to valve type, implant depth, and anatomic features. Invitro experiments used particle image velocimetry to observe changes in sinus flow based on the transcatheter heart valves (23-mm SAPIEN3, Edwards Lifesciences; and 29-mm CoreValve, Medtronic) height and coronary artery flow. Native sinus thrombosis was more common in self-expanding valves (39.1% versus 14.9%, P=0.004). In per-cusp analysis of invivo patient data, adjusted transcatheter heart valve implant depth (odds ratio, 1.2 [95% CI, 1.1-1.3]; P<0.001), noncoronary sinus of Valsalva (odds ratio, 4.0 [95% CI, 2.0-7.8]; P<0.001), sinus inflow diameter (odds ratio, 0.8 [95% CI, 0.6-0.9]; P=0.008), and implanted valve size (odds ratio, 0.8 [95% CI, 0.7-1.0]; P=0.025) were significant factors associated with native sinus thrombosis. In the invitro experiments, CoreValve showed noticeable flow stasis compared with SAPIEN3. High-positioned SAPIEN3 was linked to reduced velocity within the native sinus of Valsalva. Coronary artery flow led to higher sinus velocity and improved particle washout, reducing sinus thrombosis risk. This study provides insights into the relationship between transcatheter heart valve deployment and native sinus thrombosis, emphasizing the role of anatomic factors in relation to the risk of sinus thrombosis.

Computing pulsatile blood flow of coronary artery under incomplete boundary conditions

BackgroundAccurate measurement of pulsatile blood flow in the coronary arteries enables coronary wave intensity analysis, which can serve as an indicator for assessing coronary artery physiology and myocardial viability. Computational fluid dynamics (CFD) methods integrating coronary angiography images and fractional flow reserve (FFR) offer a novel approach for computing mean coronary blood flow. However, previous methods neglect the inertial effect of blood flow, which may have great impact on pulsatile blood flow calculation. To improve the accuracy of pulsatile blood flow calculation, a novel CFD based method considering the inertia term is proposed. MethodsA flow resistance model based on Pressure-Flow vs.Time curves is proposed to model the resistance of the epicardial artery. The parameters of the flow resistance model can be fitted from the simulated pulsating flow rates and pressure drops of a specific mode. Then, pulsating blood flow can be calculated by combining the incomplete pressure boundary conditions under pulsating conditions which are easily obtained in clinic. Through simulation experiments, the effectiveness of the proposed method is validated in idealized and reconstructed 3D model of coronary artery. The impacts of key parameters for generating the simulated pulsating flow rates and pressure drops on the accuracy of pulsatile blood flow calculation are also investigated. ResultsFor the idealized model, the previously proposed Pressure-Flow model has a significant leading effect on the computed blood flow waveform in the moderate model, and this leading effect disappears with the increase of the degree of stenosis. The improved model proposed in this paper has no leading effect, the root mean square error (RMSE) of the proposed model is low (the left coronary mode:≤0.0160, the right coronary mode:≤0.0065) for all simulated models, and the RMSE decreases with an increase of stenosis. The RMSE is consistently small (≤0.0217) as the key parameters of the proposed method vary in a large range. It is verified in the reconstructed model that the proposed model significantly reduces the RMSE of patients with moderate stenosis (the Pressure-Flow model:≤0.0683, the Pressure-Flow vs.Time model:≤0.0297), and the obtained blood flow waveform has a higher coincidence with the simulated reference waveform. ConclusionsThis paper confirms that ignoring the effect of inertia term can significantly affect the accuracy of calculating pulsatile blood flow in moderate stenosis lesions, and the new method proposed in this paper can significantly improves the accuracy of calculating pulsatile blood flow in moderate stenosis lesions. The proposed method provides a convenient clinical method for obtaining pressure-synchronized blood flow, which is expected to facilitate the application of waveform analysis in the diagnosis of coronary artery disease.

Competitive Flow of Terminal Anastomosis to Right Coronary Territory in “Y” Coronary Artery Bypass

BackgroundWe evaluated the prevalence and outcomes of competitive flow in the terminal right coronary artery (RCA) graft after coronary artery bypass grafting (CABG) with left internal thoracic artery–based Y-composite grafting at 1 year after CABG. MethodsWe enrolled 642 patients who underwent Y-composite graft–based off-pump CABG with in situ left internal thoracic artery between 2014 and 2022. All patients underwent early postoperative angiography, and 1-year postoperative angiography was performed in 81.2% (522/642) of patients. ResultsThe early occlusion rate of distal anastomoses with Y-composite graft was 2.1%. Competitive flow was observed in 69 of 642 anastomoses (10.7%). Multivariate analysis showed that the maximal degree of target vessel stenosis (odds ratio [OR], 0.909; 95% CI, 0.886-0.931; P < .001), maximal degree of non–terminal target vessel in Y-arm grafts (OR, 1.103; 95% CI, 1.047-1.172; P < .001), and diabetes mellitus (OR, 0.535; 95% CI, 0.303-0.934; P = .029) were factors associated with competitive flow to the RCA territory. The optimal cutoff value for the degree of terminal target vessel stenosis predicting competitive flow to the RCA territory was 92.5%. The 1-year graft failure rate of anastomoses with competitive flow of the terminal anastomosis was 30.9% (17/55). The presence of competitive flow on early angiography was the only factor associated with graft occlusion of the terminal anastomosis at 1 year (OR, 2.339; 95% CI, 1.165-4.481; P = .013). ConclusionsFor terminal anastomosis to the RCA territory in Y-composite graft–based CABG, the presence of competitive flow on early angiography was associated with graft occlusion of the terminal anastomosis at 1 year. Notably, 30.9% of these grafts demonstrated failure on 1-year follow-up angiography.

Numerical simulation of blood flow in coronary bifurcation

A numerical simulation of blood flow in a Y-shaped coronary artery was executed by constructing ideal geometric models. The influences of bifurcation angle, the initial velocity of inlet blood flow, and the diameter ratio of bifurcated vessels on the blood flow velocity field, wall shear stress, wall pressure, etc. were analyzed. The blood velocity at the bifurcation of the blood vessel was slower, while the wall shear stress and wall pressure value were higher. The wall shear stress and wall pressure increased with the increase of blood flow velocity at the entrance. Greater bifurcation angle led to higher wall shear stress. With the increase of the diameter ratio of the two branches, the maximum value of the shear stress became smaller. The probability of thrombosis formation increases as the diameter ratio increases. The numerical results showed that the bifurcation of the blood vessel is the optimal place to form the thrombosis.

Computational simulation of blood flow in the right coronary artery and the interaction between the blood flow and the arterial wall

Computational simulation of blood flow in the right coronary artery and the interaction between the blood flow and the arterial wall

Significance of Smoking in Patients with Acute ST Elevation Myocardial Infarction (STEMI) Undergoing Primary Percutaneous Coronary Intervention: Evaluation of Coronary Flow, Microcirculation and Left Ventricular Systolic Function

In the thrombolytic care era, myocardial infarction in cigarette smokers was associated with better six-month outcomes compared to non-smokers. Aims: We tested the hypothesis that in patients with anterior myocardial infarction with ST-segment elevation (STEMI) treated with primary percutaneous coronary intervention (PPCI), cigarette smoking is associated with better coronary artery flow, myocardial perfusion, and left ventricular systolic function. Methods: Ninety-nine patients (sixty-six smokers) with anterior STEMI treated with PPCI were studied. Angiographic coronary artery flow TIMI grades, myocardial blush grades (MBGs) before and after PPCI, ST-segment elevation resolution, maximal troponin I and creatine phosphokinase blood levels, left ventricular echocardiographic systolic function as well as left anterior descending coronary artery (LAD) velocity parameters at admission and at discharge were evaluated. Results: Smokers and non-smokers were treated similarly. In smokers, the age was significantly younger, 54 ± 10, compared to non-smokers, 71.8 ± 10 years, p &lt; 0.05, and had a lower prevalence of women, 13.6% compared to 36.6%. TIMI and MBG before and after PPCI were similar between smokers and non-smokers. Smokers had a lower prevalence of complete ST elevation resolution, 33% compared to 50% in non-smokers. Diastolic LAD velocity and integral were lower in smokers, p &lt; 0.05. Maximal biomarker blood levels as well as LV systolic function at admission and on discharge were similar. Conclusions: Cigarette smokers with anterior STEMI treated with PPCI were younger with a lower prevalence of women and of complete ST elevation resolution and had lower LAD diastolic velocity and integral late after PPCI. However, angiographic parameters and LV systolic function parameters were similar.

Evaluation of models of sequestration flow in coronary arteries—Physiology versus anatomy?

Background:Myocardial ischaemia results from insufficient coronary blood flow. Computed virtual fractional flow reserve (vFFR) allows quantification of proportional flow loss without the need for invasive pressure-wire testing. In the current study, we describe a novel, conductivity model of side branch flow, referred to as ‘leak’. This leak model is a function of taper and local pressure, the latter of which may change radically when focal disease is present. This builds upon previous techniques, which either ignore side branch flow, or rely purely on anatomical factors. This study aimed to describe a new, conductivity model of side branch flow and compare this with established anatomical models. Methods and results:The novel technique was used to quantify vFFR, distal absolute flow (Qd) and microvascular resistance (CMVR) in 325 idealised 1D models of coronary arteries, modelled from invasive clinical data. Outputs were compared to an established anatomical model of flow. The conductivity model correlated and agreed with the reference model for vFFR (r = 0.895, p < 0.0001; ＋0.02, 95% CI 0.00 to ＋ 0.22), Qd (r = 0.959, p < 0.0001; −5.2 mL/min, 95% CI −52.2 to ＋13.0) and CMVR (r = 0.624, p < 0.0001; ＋50 Woods Units, 95% CI −325 to ＋2549). Conclusion:Agreement between the two techniques was closest for vFFR, with greater proportional differences seen for Qd and CMVR. The conductivity function assumes vessel taper was optimised for the healthy state and that CMVR was not affected by local disease. The latter may be addressed with further refinement of the technique or inferred from complementary image data. The conductivity technique may represent a refinement of current techniques for modelling coronary side-branch flow. Further work is needed to validate the technique against invasive clinical data.

Slow flow in ectatic dilated coronary arteries as the cause of sudden cardiac arrest during diagnostic coronary angiography.

Slow flow in ectatic dilated coronary arteries as the cause of sudden cardiac arrest during diagnostic coronary angiography.

Application of ultrasound diagnosis in cardiac and liver diseases

Ultrasonography is a non-invasive imaging modality widely used to evaluate and diagnose many diseases. The purpose of this article is to provide a more detailed overview of the use of ultrasound in the diagnosis of heart and liver disease. In addition to a basic introduction to heart and liver disease, this article will explore specific applications of ultrasound in specific heart and liver diseases. In terms of heart disease, ultrasound plays an important role in the diagnosis of coronary atherosclerotic heart disease, valvular heart disease and congenital heart disease. Ultrasound can assess the degree of narrowing and blood flow in coronary arteries to help determine a patient's cardiovascular risk. For valvular heart disease, ultrasound can detect and evaluate the function and abnormality of the heart valves, providing information about valve stenosis or regurgitation. For congenital heart disease, ultrasound can reveal structural abnormalities and hemodynamic changes in the heart, helping to determine the type and severity of the lesion. In liver disease, ultrasound plays an important role in the evaluation of pathologies such as cirrhosis and hepatocellular carcinoma. Ultrasound can assess the shape, size, and texture of the liver, help detect and diagnose cirrhosis, and assess liver function and disease progression. In addition, ultrasound is also of great significance for the early diagnosis and monitoring of hepatocellular carcinoma, which can reveal the location, size and blood flow of the tumor. The role of ultrasound in diagnosing and monitoring disease will expand further with advances in technologies such as artificial intelligence and elastography. In conclusion, ultrasound plays a key role in the assessment, diagnosis and monitoring of heart and liver diseases and has many advantages. With the further development of technology and the expansion of application, the position of ultrasound in clinical practice will be further strengthened.

Patient-specific in silico 3D coronary model in cardiac catheterisation laboratories.

Coronary artery disease is caused by the buildup of atherosclerotic plaque in the coronary arteries, affecting the blood supply to the heart, one of the leading causes of death around the world. X-ray coronary angiography is the most common procedure for diagnosing coronary artery disease, which uses contrast material and x-rays to observe vascular lesions. With this type of procedure, blood flow in coronary arteries is viewed in real-time, making it possible to detect stenoses precisely and control percutaneous coronary interventions and stent insertions. Angiograms of coronary arteries are used to plan the necessary revascularisation procedures based on the calculation of occlusions and the affected segments. However, their interpretation in cardiac catheterisation laboratories presently relies on sequentially evaluating multiple 2D image projections, which limits measuring lesion severity, identifying the true shape of vessels, and analysing quantitative data. In silico modelling, which involves computational simulations of patient-specific data, can revolutionise interventional cardiology by providing valuable insights and optimising treatment methods. This paper explores the challenges and future directions associated with applying patient-specific in silico models in catheterisation laboratories. We discuss the implications of the lack of patient-specific in silico models and how their absence hinders the ability to accurately predict and assess the behaviour of individual patients during interventional procedures. Then, we introduce the different components of a typical patient-specific in silico model and explore the potential future directions to bridge this gap and promote the development and utilisation of patient-specific in silico models in the catheterisation laboratories.

Factors affecting TIMI (Thrombolysis In Myocardial Infarction) flow grade in patients undergoing primary PCI (Percutaneous Coronary Intervention).

Objective: To determine the causes of normal blood flow in coronary arteries in patients presenting with STEMI and receiving pPCI. Study Design: Observational study conducted retrospectively. Setting: National Institute of Cardiovascular Disease (NICVD) Karachi, Cath Lab. Period: August 17 2020 to November 2020. Material &amp; Methods: Data was obtained from patients presented to the emergency department with STEMI and experienced primary PCI in last two years from January 2016 to Decemebr 2018.Social Sciences (SPSS) version 19 was used analyze these data.Th in those patients who had suboptimal coronary blood flow. Young patients &lt;40 years of age had more (14%) normal coronary blood flow as compared to elders i.e &gt;40 years. Diabetes mellitus, Hypertension, and smoking had no significant impact on coronary blood flow in these patients. Conclusion: In this study, it was found that most of the coronary arteries had abnormal blood flow during primary PCI. Multiple factors are affecting the blood flow in coronaries. The onset of symptoms and the time presented in the hospital was the main factors. Further studies are required to find more reasons for having normal blood flow in coronaries in STEMI.

The impact of microcirculation improvements of coronary artery flow on macrocirculation after coronary intervention

Abstract Background The impact of microcirculation changes of coronary artery after percutaneous coronary intervention (PCI) and its association with macrocirculation remained obscured. Purpose This study aimed to investigate the impact of microcirculation changes of coronary artery flow on macrocirculation after coronary intervention. Methods This prospective study enrolled patients who underwent PCI. Electrical cardiometry was used for hemodynamics measurement before and after PCI. Deidentified data of patients in this study cohort were analyzed. Moreover, peri-procedural deidentified N-terminal-pro-B type natriuretic peptide level (NT-proBNP) values were analyzed. Results There was a total of 40 patients. The mean age was 62.1± 12.1 years, and there was male dominant (82.5%). The index of contractility (ICON) and stroke volume index worsened after PCI but improved on the next day after the procedural day. In addition, systemic vascular resistance index decreased and the improvement of ICON on the next day had remarkable contribution on the overall contractility rather than transient diminution after intervention. Hierarchical Clustering indicated that PCI had benefits for young patients, heart failure population, and patients with moderate to severe Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery score. In addition, NT-proBNP values were analyzed, which reported a decreasing trend of level after intervention. Conclusions This study supported that PCI improved coronary flow and myocardial contractility over time after conquering the microvascular impedance. Moreover, microcirculation of coronary flow had impact on macrocirculation improvement, and it was feasible to measure the change by using electrical cardiometry.Figure 1Figure 2

Coronary Flow Reserve Changes after Angiotensin Receptor-Neprilysin Inhibitor Treatment in Heart Failure with Reduced Ejection Fraction.

Sacubitril/valsartan has been shown to reduce hospital admissions and even mortality for heart failure. In heart failure and acute coronary syndrome, the effects of sacubitril/valsartan have been studied, but the effect on coronary artery flow is not known. We aimed to understand the effect of sacubitril/valsartan on coronary artery flow by using echocardiographic coronary flow reserve (CFR). Thirty-six patients (17 ischemic and 19 non-ischemic) with heart failure with reduced ejection fraction (EF of < 40%) eligible for sacubitril/valsartan treatment and 21 normal controls were recruited. The study group and controls were similar with regard to gender, smoking status, and age distribution (p = 0.874, p = 0.709, and p = 0.765, respectively). Blood pressure, heart rate, 6-minute walk test (6MWT), N terminal pro B type natriuretic peptide (NT-pro-BNP) level, standard echocardiography, from where left anterior descending mid-distal flow was seen, baseline peak diastolic flow rate and 2 minutes after dipyridamole infusion, and hyperemic peak diastolic flow rate were measured, and CFR with echocardiography was assessed prior to and at 6 months after sacubitril/valsartan initiation. Baseline peak diastolic flow rate did not exhibit a significant difference at 6 months (p = 0.143), but hyperemic peak diastolic flow rate, CFR, EF (%), and 6MWD values were significantly increased (all p < 0.001), and New York Heart Association Functional Class, NT-pro-BNP (pg/mL), left ventricule end diastolic diameter (mm), and left ventricule end systolic diameter (mm) values were significantly decreased (all p < 0.001) after sacubitril/valsartan treatment. Sacubitril/valsartan significantly alters coronary blood flow, especially its dynamic features, in patients with heart failure with reduced ejection fraction.

The Differences of Quantitative Flow Ratio in Coronary Artery Stenosis with or without Atrial Fibrillation.

Quantitative flow ratio (QFR) is a new method for the assessment of the extent of coronary artery stenosis. But it may be obscured by the cardiac remodeling and abnormal blood flow of the coronary artery when encountering atrial fibrillation (AF). The present study aimed to examine the impact of these changed structures and blood flow of coronary arteries on QFR results in AF patients. Methods and Results. We evaluated QFR in 223 patients (112 patients with AF; 111 non-AF patients served as controls) who had undergone percutaneous coronary intervention (PCI) due to severe stenoses in coronary arteries. QFR of the target coronary was determined according to the flow rate of the contrast agent. Results showed that AF patients had significantly higher QFR values than control (0.792 ± 0.118 vs. 0.685 ± 0.167, p < 0.001). We further analyzed local QFR around the stenoses (0.858 ± 0.304 vs. 0.756 ± 0.146, p=0.002), residual QFR (0.958 ± 0.055 vs. 0.929 ± 0.093, p=0.005), and index QFR (0.807 ± 0.108 vs. 0.713 ± 0.152, p < 0.001) in these two groups of patients with and without AF. Further analysis revealed that QFR in AF patients was negatively correlated with coronary flow velocity (R = -0.22, p=0.02) and area of stenosis (R = -0.70, p < 0.001) but positively correlated with the minimum lumen area (MLA) (R = 0.47, p < 0.001). Conclusion. AF patients with coronary artery stenosis have higher QFR values, which are associated with decreased blood flow velocity, smaller stenosis, and larger MLA in AF patients upon cardiac remodeling.

THU657 Racing Hearts: A Closer Look At The Connection Between Hyperthyroidism And Coronary Vasospasm

Abstract Disclosure: A. Elahi: None. R.I. Mateo: None. The cardiovascular system is a major target of thyroid hormone action in which subtle changes in thyroid function can lead to cardiac complications such as coronary vasospasm. There are many proposed mechanisms in how this occurs, but further studies are needed to understand the specific pathophysiology. This case illustrates the clinical relevance of encountering a hyperthyroid patient complaining of chest pain and how to address it in real work practice. A 62 year old African American male with history of Graves hyperthyroidism, type 2 diabetes, hypertension, peripheral artery disease, and stroke with residual aphasia presented with acute onset chest pain, shortness of breath, and palpitations. He was noncompliant with his methimazole (MMI) and subsequent labs were significant for free T4 of 2.5 ng/dL, undetectable TSH, and free T3 of 11.53 pg/mL. His high sensitivity troponins were elevated at 29,569 ng/dL. EKG showed sinus tachycardia with T-wave inversions in leads II, III, and AVF with a bedside echo showing inferior lateral wall motion abnormality. He was started on MMI 20mg daily and admitted to the intensive care unit for non-ST elevation myocardial infarction management. Left heart catheterization (LHC) was done after 1 dose of MMI with findings suggestive of vasospasm; specifically, decreased blood flow of the right coronary artery which improved when the catheter was withdrawn and significant dampening of the arterial wave form of the left main coronary artery. Given the unclear differentiation between true coronary artery disease and vasospasm he needed a repeat LHC once his hyperthyroidism was more controlled. His free T3 levels were monitored every 1-2 days with administration of escalating doses of MMI up to 40mg daily. By day 7 of admission, his free T3 level was 4.54 pg/mL, free T4 was 2 ng/dL and repeat LHC was performed showing open vessel lumens with multiple occlusions requiring 2 stents in the right coronary artery and 1 stent in the left circumflex artery. Given that thyroid hormone receptors are present in the myocardium and vascular tissue, alterations in thyroid hormone concentration can affect cardiovascular function. The documentation of coronary spasm, however, is rare and to date, there are only a few limited cases describing the underlying pathophysiology. This case illustrates via cardiac catheterization images and corresponding labs, the positive correlation of coronary vasospasm with thyroid hormone levels in hyperthyroidism. Presentation: Thursday, June 15, 2023

Modelling blood flow in coronary arteries: Newtonian or shear-thinning non-Newtonian rheology?

BackgroundThe combination of medical imaging and computational hemodynamics is a promising technology to diagnose/prognose coronary artery disease (CAD). However, the clinical translation of in silico hemodynamic models is still hampered by assumptions/idealizations that must be introduced in model-based strategies and that necessarily imply uncertainty. This study aims to provide a definite answer to the open question of how to properly model blood rheological properties in computational fluid dynamics (CFD) simulations of coronary hemodynamics. MethodsThe geometry of the right coronary artery (RCA) of 144 hemodynamically stable patients with different stenosis degree were reconstructed from angiography. On them, unsteady-state CFD simulations were carried out. On each reconstructed RCA two different simulation strategies were applied to account for blood rheological properties, implementing (i) a Newtonian (N) and (ii) a shear-thinning non-Newtonian (non-N) rheological model. Their impact was evaluated in terms of wall shear stress (WSS magnitude, multidirectionality, topological skeleton) and helical flow (strength, topology) profiles. Additionally, luminal surface areas (SAs) exposed to shear disturbances were identified and the co-localization of paired N and non-N SAs was quantified in terms of similarity index (SI). ResultsThe comparison between paired N vs. shear-thinning non-N simulations revealed remarkably similar profiles of WSS-based and helicity-based quantities, independent of the adopted blood rheology model and of the degree of stenosis of the vessel. Statistically, for each paired N and non-N hemodynamic quantity emerged negligible bias from Bland-Altman plots, and strong positive linear correlation (r > 0.94 for almost all the WSS-based quantities, r > 0.99 for helicity-based quantities). Moreover, a remarkable co-localization of N vs. non-N luminal SAs exposed to disturbed shear clearly emerged (SI distribution 0.95 [0.93, 0.97]). Helical flow topology resulted to be unaffected by blood rheological properties. ConclusionsThis study, performed on 288 angio-based CFD simulations on 144 RCA models presenting with different degrees of stenosis, suggests that the assumptions on blood rheology have negligible impact both on WSS and helical flow profiles associated with CAD, thus definitively answering to the question “is Newtonian assumption for blood rheology adequate in coronary hemodynamics simulations?”.