Myocardial Perfusion Abnormalities Research Articles

Prognostic value of a novel artificial intelligence-based coronary CTA-derived ischemia algorithm among patients with normal or abnormal myocardial perfusion

BackgroundAmong patients with obstructive coronary artery disease (CAD) on coronary computed tomography angiography (CTA), downstream positron emission tomography (PET) perfusion imaging can be performed to assess the presence of myocardial ischemia. A novel artificial-intelligence-guided quantitative computed tomography ischemia algorithm (AI-QCTischemia) aims to predict ischemia directly from coronary CTA images. We aimed to study the prognostic value of AI-QCTischemia among patients with obstructive CAD on coronary CTA and normal or abnormal downstream PET perfusion. MethodsAI-QCTischemia was calculated by blinded analysts among patients from the retrospective coronary CTA cohort at Turku University Hospital, Finland, with obstructive CAD on initial visual reading (diameter stenosis ≥50%) being referred for downstream 15O-H2O-PET adenosine stress perfusion imaging. All coronary arteries with their side branches were assessed by AI-QCTischemia. Absolute stress myocardial blood flow ≤2.3 ​ml/g/min in ≥2 adjacent segments was considered abnormal. The primary endpoint was death, myocardial infarction, or unstable angina pectoris. The median follow-up was 6.2 [IQR 4.4–8.3] years. Results662 of 768 (86%) patients had conclusive AI-QCTischemia result. In patients with normal 15O-H2O-PET perfusion, an abnormal AI-QCTischemia result (n ​= ​147/331) vs. normal AI-QCTischemia result (n ​= ​184/331) was associated with a significantly higher crude and adjusted rates of the primary endpoint (adjusted HR 2.47, 95% CI 1.17–5.21, p ​= ​0.018). This did not pertain to patients with abnormal 15O-H2O-PET perfusion (abnormal AI-QCTischemia result (n ​= ​269/331) vs. normal AI-QCTischemia result (n ​= ​62/331); adjusted HR 1.09, 95% CI 0.58–2.02, p ​= ​0.794) (p-interaction ​= ​0.039). ConclusionAmong patients with obstructive CAD on coronary CTA referred for downstream 15O-H2O-PET perfusion imaging, AI-QCTischemia showed incremental prognostic value among patients with preserved perfusion by 15O-H2O-PET imaging, but not among those with reduced perfusion.

Myocardial perfusion in cardiac amyloidosis.

Cardiac involvement is the main driver of clinical outcomes in systemic amyloidosis and preliminary studies support the hypothesis that myocardial ischaemia contributes to cellular damage. The aims of this study were to assess the presence and mechanisms of myocardial ischaemia using cardiovascular magnetic resonance (CMR) with multiparametric mapping and histopathological assessment. Ninety-three patients with cardiac amyloidosis (CA) (light-chain amyloidosis n = 42, transthyretin amyloidosis n = 51) and 97 without CA (three-vessel coronary disease [3VD] n = 47, unobstructed coronary arteries n = 26, healthy volunteers [HV] n = 24) underwent quantitative stress perfusion CMR with myocardial blood flow (MBF) mapping. Twenty-four myocardial biopsies and three explanted hearts with CA were analysed histopathologically. Stress MBF was severely reduced in patients with CA with lower values than patients with 3VD, unobstructed coronary arteries and HV (CA: 1.04 ± 0.51 ml/min/g, 3VD: 1.35 ± 0.50 ml/min/g, unobstructed coronary arteries: 2.92 ± 0.52 ml/min/g, HV: 2.91 ± 0.73 ml/min/g; CA vs. 3VD p = 0.011, CA vs. unobstructed coronary arteries p < 0.001, CA vs. HV p < 0.001). Myocardial perfusion abnormalities correlated with amyloid burden, systolic and diastolic function, structural parameters and blood biomarkers (p < 0.05). Biopsies demonstrated abnormal vascular endothelial growth factor staining in cardiomyocytes and endothelial cells, which may be related to hypoxia conditions. Amyloid infiltration in intramural arteries was associated with severe lumen reduction and severe reduction in capillary density. Cardiac amyloidosis is associated with severe inducible myocardial ischaemia demonstrable by histology and CMR stress perfusion mapping. Histological evaluation indicates a complex pathophysiology, where in addition to systolic and diastolic dysfunction, amyloid infiltration of the epicardial arteries and disruption and rarefaction of the capillaries play a role in contributing to myocardial ischaemia.

Association of Income Level and Ischemic Heart Disease: Potential Role of Walkability.

Association of Income Level and Ischemic Heart Disease: Potential Role of Walkability Association of ischemic heart disease (adjusted for traditional risk factors and socioeconomics variables) and income level (A), and walkability z-score (B), and association of walkability z-score and income level (C). Socioeconomic status has been linked to ischemic heart disease (IHD). High-income neighborhoods may expose individuals to a walking-promoting built environment for daily activities (walkability). Data from the association between income and IHD is lacking in middle-income countries. It is also uncertain whether walkability mediates this association. To investigate whether income is associated with IHD in a middle-income country and whether neighborhood walkability mediates the income-IHD association. This cross-sectional study evaluated 44,589 patients referred for myocardial perfusion imaging (SPECT-MPI). Income and walkability were derived from participants' residential census tract. Walkability quantitative score combined 4 variables: street connectivity, residential density, commercial density, and mixed land use. IHD was defined by abnormal myocardial perfusion during a SPECT-MPI study. We used adjusted mixed effects models to evaluate the association between income level and IHD, and we performed a mediation analysis to measure the percentage of the income-IHD association mediated by walkability. We considered p values below 0.01 as statistically significant. From 26,415 participants, those living in the lowest-income tertile census tract were more physically inactive (79.1% versus 75.8% versus 72.7%) when compared to higher-income tertile census tracts (p < 0.001). Income was associated with IHD (odds ratio: 0.91 [95% confidence interval: 0.87 to 0.96] for each 1,000.00 international dollars increase in income) for both men and women equally (p for interaction = 0.47). Census tracts with a higher income were associated with better walkability (p < 0.001); however, walkability did not mediate the income-IHD association (percent mediated = -0.3%). Income was independently associated with higher prevalence of IHD in a middle-income country irrespective of gender. Although walkability was associated with census tract income, it did not mediate the income-IHD association.

Validation of the resting full-cycle ratio and diastolic pressure ratio through myocardial perfusion imaging with [15O]H2O positron emission tomography

Abstract Background Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are invasive techniques used to evaluate the hemodynamic significance of coronary artery stenosis. These methods have been validated through perfusion imaging techniques and clinical trials. However, new invasive pressure indices that do not require hyperemia have recently emerged, and it is essential to confirm their diagnostic efficacy. Purpose To validate the resting full-cycle ratio (RFR) and the diastolic pressure ratio (dPR), against [15O]H2O positron emission tomography (PET) imaging. Methods A total of 129 symptomatic patients with an intermediate risk of coronary artery disease (CAD) were included. All patients underwent cardiac [15O]H2O PET with quantitative assessment of myocardial perfusion, and within 2 weeks coronary angiography was performed. Intracoronary pressure measurements were obtained in 320 vessels and RFR, dPR, and FFR were computed. In the case of RFR and dPR, values ≤ 0.89, and for FFR, values ≤ 0.8 were classified as abnormal. PET myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) served as reference standards. The index tests and gold standard results were evaluated by blinded researchers. Results Figure 1 shows the diagnostic performance of each ratio in coronary arteries with stenoses (136 of 320 vessels, 38%). The overall diagnostic accuracies of RFR, dPR and FFR did not differ when PET MBF &amp;lt; 2.3 ml · min-1 and PET MPR &amp;lt; 2.5 were considered as the reference standard. No significant differences were observed in the areas under the receiver-operating-characteristic (ROC) curve among the indices (Figure 2). In addition, the indices demonstrated comparable performance when the analysis included all of the vessels. Conclusion The novel non-hyperemic pressure ratios, RFR and dPR, have a diagnostic performance that is comparable to FFR when using [15O]H2O PET to assess myocardial perfusion abnormalities. These findings suggest that RFR and dPR may be considered for clinical use in symptomatic patients with CAD.Figure 1Diagnostic performance;StenosisFigure 2ROC curve analysis;Stenosis

Abstract 13074: Incremental Value of Abnormal Quantitative Myocardial Perfusion and Myocardial Infarction Using Cardiovascular Magnetic Resonance as Prognostic Markers in Type 2 Diabetes Mellitus

Introduction: Abnormal myocardial perfusion and MI are each associated with cardiovascular events in individuals with diabetes mellitus (DM). Hypothesis: We hypothesised that, in patients with T2DM, CMR determined quantitative myocardial perfusion and MI are independent predictors of major adverse cardiovascular and cerebrovascular events (MACCE) and that the presence of both offers incremental prognostic value. Methods: A prospective multicentre cohort of individuals with T2DM and healthy controls underwent stress CMR with inline quantitative myocardial perfusion and late gadolinium enhancement (LGE). Adjusted cox proportional hazard models (adjusted for age, sex, LVEF, LV end diastolic volume (LVEDV) and LV mass quantified associations between quantitative myocardial perfusion and MI with MACCE (composite of all-cause death, MI, stroke, heart failure hospitalisation and coronary revascularisation). Results: A total of 572 participants with T2DM from four centres and 52 healthy controls were followed for a median of 851 (IQR 765-935) days, during which 82 (14%) participants accrued at least one MACCE, including 25 (4%) deaths. Presence of either CMR pathology was associated with increased MACCE (normal quantitative myocardial perfusion and no MI: 7% MACCE; abnormal quantitative myocardial perfusion or MI: 13% MACCE (adjusted HR compared with normal 2.06 (95% CI 1.07-3.97, p=0.03)); and both abnormal quantitative myocardial perfusion and MI was associated with the highest event rate: 28% MACCE (adjusted HR compared with normal quantitative myocardial perfusion and no MI 4.55 (95% CI 2.32-8.90, p&lt;0.001)). Conclusion: In individuals with T2DM, the presence of either abnormal quantitative myocardial perfusion or MI is associated with MACCE and the presence of both offers strong incremental prognostic value.

Abstract 15772: From Agony to Relief: Overcoming Angina Through Endovascular Coiling of the Left Internal Mammary Artery (LIMA) to Pulmonary Artery (PA) Fistulae- A Case Report

Introduction: LIMA to PA fistulae are a rare complication after coronary artery bypass graft (CABG) surgery. We present a patient with angina secondary to a steal syndrome from LIMA-PA fistulae, treated with endovascular coiling. Case: The patient is a 49-year-old active male with coronary artery disease, status post CABG at age 46 with a LIMA graft to the left anterior descending artery, radial artery graft to the first obtuse marginal artery, and saphenous venous graft (SVG) to the posterior descending artery. At age 48, he developed angina and underwent stent placement to the distal right coronary artery after the SVG was found to be occluded. Several months later, he reported dyspnea and chest pain on exertion. An exercise nuclear stress test showed abnormal myocardial perfusion in the anteroseptal region, and he was referred for left heart catheterization (LHC). LHC revealed unchanged native coronary disease, patent LIMA, and a network of collateral vessels from the LIMA feeding into the pulmonary vasculature (Figure 1). The collaterals were not seen on LHC 9 months prior. CT coronary angiography confirmed multiple fistulae originating from the superior aspect of the LIMA graft communicating with the PA (Figure 1). After a multidisciplinary, patient-centered, heart team discussion, he underwent successful endovascular coiling of the collateral branches (Figure 2). Discussion: LIMA-PA fistulae is a rare cause of angina and there is a paucity of literature on management. To our knowledge, coil embolization has been described in roughly 10 cases. Here, we present a successful case of endovascular coiling of collateral vessels leading to symptomatic improvement.

Impact of myocardial perfusion and coronary calcium on medical management for coronary artery disease.

Single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) remains one of the most widely used imaging modalities for the diagnosis and prognostication of coronary artery disease (CAD). Despite the extensive prognostic information provided by MPI, little is known about how this influences the prescription of medical therapy for CAD. We evaluated the relationship between MPI with computed tomography (CT) attenuation correction and prescription of acetylsalicylic acid (ASA) and statins. We performed a retrospective analysis of consecutive patients who underwent SPECT MPI at a single centre between 2015 and 2021. Myocardial perfusion abnormalities and coronary calcium burden were assessed, with attenuation correction imaging 77.8% of patients. Medication prescriptions before and within 180 days after the test were compared. Associations between abnormal perfusion and calcium burden with ASA and statin prescription were assessed using multivariable logistic regression. In total, 9908 patients were included, with a mean age 66.8 ± 11.7 years and 5337 (53.9%) males. The prescription of statins increased more in patients with abnormal perfusion (increase of 19.2 vs. 12.0%, P < 0.001). Similarly, the presence of extensive CAC led to a greater increase in statin prescription compared with no calcium (increase 12.1 vs. 7.8%, P < 0.001). In multivariable analyses, ischaemia and coronary artery calcium were independently associated with ASA and statin prescription. Abnormal MPI testing was associated with significant changes in medical therapy. Both calcium burden and perfusion abnormalities were associated with increased prescriptions of medical therapy for CAD.

Comprehensive invasive evaluation of coronary microcirculation in patients with Takotsubo syndrome

Background and aimsThe etiology and pathophysiology of Takotsubo syndrome (TTS) remain a matter of debate. In murine models of coronary microvascular dysfunction (CMD), abnormalities in myocardial perfusion led to the development of TTS. Importantly, TTS was reversible when normal perfusion was restored. However, in clinical practice, the assessment of coronary microcirculation in patients with TTS has primarily relied on non-invasive or indirect, angiography-derived methods. Methods and ResultsFor the first time, we performed invasive microcirculatory assessment, by both validated techniques currently available in the catheterization laboratory, namely intracoronary bolus and continuous thermodilution, in patients with TTS, upon hospital admission and at short term follow-up. Our findings demonstrate that CMD was consistently present in all patients upon hospital admission, as assessed by both techniques. At a median follow-up of 3 months, after the recovery of left ventricular ejection fraction, two third of patients no longer exhibited CMD. ConclusionsThese findings support the hypothesis that an acute and transient worsening in coronary microvascular function plays a pivotal role in the pathophysiology of TTS.

Cardiovascular outcomes and mortality after abnormal myocardial perfusion scans in the elderly: a retrospective study at a tertiary care institution.

Cardiovascular outcomes and mortality after abnormal myocardial perfusion scans in the elderly: a retrospective study at a tertiary care institution.

Does financial hardship associate with abnormal quantitative myocardial perfusion and major adverse cardiovascular event?

BackgroundData on impact of financial hardship on coronary artery disease (CAD) remain incomplete. MethodsConsecutive subjects referred for clinical rest/stress cardiac positron emission tomography (PET) were enrolled. Financial hardship is defined as patients’ inability to pay for their out-of-pocket expense for cardiac PET. Abnormal cardiac PET is defined as at least moderate relative perfusion defects at stress involving > 10% of the left ventricle or global coronary flow reserve ≤ 2.0. Patients were followed for major adverse cardiovascular event (MACE) comprised of all-cause mortality, non-fatal myocardial infarction, and late coronary revascularization. ResultsWe analyzed a total of 4173 patients with mean age 65.6 ± 11.3 years, 72.2% men, and 93.6% reported as having medical insurance. Of these, 504 (12.1%) patients had financial hardship. On multivariable analysis, financial hardship associated with abnormal cardiac PET (odds ratio 1.377, p = 0.004) and MACE (hazard ratio 1.432, p = 0.010) and its association with MACE was mostly through direct effect with small proportion mediated by abnormal cardiac PET or known CAD. ConclusionAmong patients referred for cardiac rest/stress PET, financial hardship independently associates with myocardial perfusion abnormalities and MACE; however, its effect on MACE is largely not mediated by abnormal myocardial perfusion or known CAD suggesting distinct impact of financial hardship beyond traditional risk factors and CAD that deserves attention and intervention to effectively reduced adverse outcomes. Having medical insurance does not consistently protect from financial hardship and a more preventive-oriented restructuring may provide better outcomes at lower cost.

Non-Invasive Assessment of Myocardial Perfusion Abnormality in Type 2 Diabetic Patients Without Symptoms of Coronary Artery Disease by SPECT-MPI

Introduction: Coronary artery disease (CAD) is the most common chronic macrovascular complication of diabetes mellitus. Diabetic patients have a high incidence of silent ischemia and MI due to autonomic neuropathy. SPECT imaging is a well-established, non-invasive procedure that offers perfusion and functional information for diagnosis and risk stratification, facilitating the early detection of CAD. Objective: To detect myocardial perfusion abnormality by SPECT-MPI in type 2 diabetic patients without symptoms of CAD. Methods: A total of eighteen diabetic patients with no history of typical CAD, with or without risk factors, underwent gated SPECT-MPI using 99mTc-sestaMIBI. A single-day stress–rest protocol with adenosine was done in each patient. Result: Six out of eighteen patients (33.3%) showed abnormal scans suggestive of myocardial ischemia or infarction. Four of these patients had reversible perfusion defects, one had a fixed perfusion defect, and one had a mixed defect. Among these patients, single vessel territory was involved in three patients, and three patients had involvement in double vessel territories. Regarding the summed stress score (SSS) value, most of the patients (four) had mild risk, whereas moderate and severe risk of a future cardiac event were observed in one patient each. In addition, two patients had left ventricular dysfunction (EF&lt; 45%). Five patients with normal MPI and two patients with abnormal myocardial perfusion scans had high transient ischemic dilatation (TID). Risk factors such as male sex, hypertension, hyperlipidemia, obesity, and family history of CAD were not significantly correlated with abnormal scans. But abnormal scans were significantly related to a longer duration of diabetes (P = 0.038). Conclusion: This study showed that despite being asymptomatic, a considerable portion of diabetic patients had perfusion abnormalities, not just ischemia but also infarctions. Moreover, some of these patients are at high risk for future cardiac events as assessed by SSS, TID, and LVEF. Bangladesh J. Nuclear Med. 25(2): 110-116, 2022

Prognostic value of myocardial perfusion imaging by cadmium zinc telluride single-photon emission computed tomography in patients with suspected or known coronary artery disease: a systematic review and meta-analysis

BackgroundAim of this study was to define the prognostic value of stress myocardial perfusion imaging by cadmium zinc telluride (CZT) single-photon emission computed tomography (SPECT) for prediction of adverse cardiovascular events in patients with known or suspected coronary artery disease (CAD).Methods and resultsStudies published until November 2022 were identified by database search. We included studies using stress myocardial perfusion imaging by CZT-SPECT to evaluate subjects with known or suspected CAD and providing primary data of adverse cardiovascular events. Total of 12 studies were finally included recruiting 36,415 patients. Pooled hazard ratio (HR) for the occurrence of adverse events was 2.17 (95% confidence interval, CI, 1.78–2.65) and heterogeneity was 66.1% (P = 0.001). Five studies reported data on adjusted HR for the occurrence of adverse events. Pooled HR was 1.69 (95% CI, 1.44–1.98) and heterogeneity was 44.9% (P = 0.123). Seven studies reported data on unadjusted HR for the occurrence of adverse events. Pooled HR was 2.72 (95% CI, 2.00–3.70). Nine studies reported data useful to calculate separately the incidence rate of adverse events in patients with abnormal and normal myocardial perfusion. Pooled incidence rate ratio was 2.38 (95% CI, 1.39–4.06) and heterogeneity was 84.6% (P < 0.001). The funnel plot showed no evidence of asymmetry (P = 0.517). At meta-regression analysis, we found an association between HR for adverse events and presence of angina symptoms and family history of CAD.ConclusionsStress myocardial perfusion imaging by CZT-SPECT is a valuable noninvasive prognostic indicator for adverse cardiovascular events in patients with known or suspected CAD.

Type 2 diabetes mellitus and coronary artery disease: features of perfusion volume computed tomography of the heart in a pharmacological test with adenosine triphosphate

To study myocardial perfusion in patients with coronary artery disease (CAD) with and without type 2 diabetes mellitus (DM) using volumetric computed tomography (VCT) of the heart with a pharmacological test with adenosine triphosphate (ATP). The study included 93 patients, of which 18 had CAD with DM, and 50 had CAD without DM. All patients underwent one of the stress tests, cardiac VCT with ATP test, invasive coronary angiography, or CT coronary angiography. Left ventricle (LV) myocardial perfusion was evaluated for hypoperfusion zones and the calculation of semi-quantitative indices: decrease of LV myocardial density, LV myocardial perfusion index, transmural perfusion coefficient, and our proposed new indicator - myocardial perfusion reserve (MPR). The MPR index value in the hypoperfusion zones in patients with CAD and DM was 0.64 [0.62-0.66], in patients with CAD without diabetes 0.65 [0.63-0.66]; p=0.4; the value of the transmural perfusion coefficient in the areas of abnormal LV myocardial perfusion in patients with CAD and DM was 0.81 [0.80-0.86] versus 0.83 [0.80-0.85] in patients with CAD without DM (p=0.6). More hypoperfusion segments were observed in patients with CAD and DM (33.3%) compared to those without DM (14%; p=0.029). The MPR index in the hypoperfusion zones in patients with CAD with intact coronary arteries (CA) and DM was 0.56 [0.54-0.60] versus 0.55 [0.54-0.62] in patients with CAD with intact CA without DM; p=0.2. In patients with CAD and type 2 DM, according to the VCT with ATP test, more foci hypoperfusion areas were detected, regardless of the severity of coronary artery involvement, compared with patients with CAD without DM, which may be due to the microangiopathy in the myocardium. The similarity of the MPR parameters in the hypoperfusion zones associated with hemodynamic stenosis of the CA and with intact CAs indicates the ischemic genesis of these zones. For citation: Soboleva GN, Minasyan AA, Gaman SA, Rogoza AN, Molina LP, Soboleva TV, Shariya MA, Ternovoy SK, Karpov YuA. Type 2 diabetes mellitus and coronary artery disease: features of perfusion volume computed tomography of the heart in a pharmacological test with adenosine triphosphate. Terapevticheskii Arkhiv (Ter. Arkh.). 2023;95(4):309-315. DOI: 10.26442/00403660.2023.04.202158.

Role of Positron Emission Tomography Cardiac Perfusion Imaging in Clinical Management, Prognosis, and Risk Stratification of Cardiovascular Disease

Coronary artery disease (CAD) is an important cause of morbidity and mortality worldwide. Perfusion abnormalities precede wall motion abnormalities, ECG changes, and angina in the etiology of CAD. myocardial perfusion imaging (MPI) can detect perfusion alterations due to pathology at sites such as the endothelium, microvasculature, and epicardial coronary arteries. Thus, it measures the universal burden of ischemic heart disease (IHD). Nuclear medicine MPI is an important noninvasive imaging modality to evaluate the perfusion of the myocardium. Positron Emission Tomography (PET) and single-photon emission computed tomography (SPECT) with or without computed tomography (CT) are 2 primary modalities. PET is a highly sensitive modality with an inherent ability to quantify absolute myocardial blood flow (MBF) and variations in MBF due to various stress agents. PET has immense potential to change clinical management, prognosticate, and risk stratify patients presenting with clinical or preclinical CAD. Evidence shows that early PET detection of myocardial perfusion abnormalities, followed by aggressive intervention for cardiovascular risk factors, can reinstate myocardial perfusion. This may reduce morbidity and mortality. We shall be reviewing the clinical impact of PET in CAD and preclinical CAD patients.

Association of Long Noncoding RNA Expression Signatures with Stress-Induced Myocardial Perfusion Defects.

Stress-induced myocardial perfusion defects found in dipyridamole-thallium-201 single-photon emission computed tomography imaging may indicate vascular perfusion abnormalities and risk of obstructive or nonobstructive coronary heart disease. Besides nuclear imaging and subsequent coronary angiography (CAG), no blood test can indicate whether dysregulated homeostasis is associated with stress-induced myocardial perfusion defects. This study investigated the expression signature of long noncoding RNAs (lncRNAs) and genes involved in vascular inflammation and stress response in the blood of patients with stress-induced myocardial perfusion abnormalities (n = 27). The results revealed an expression signature consisting of the upregulation of RMRP (p < 0.01) and downregulations of THRIL (p < 0.01) and HIF1A (p < 0.01) among patients with a positive thallium stress test and no significant coronary artery stenosis within 6 months after baseline treatment. We developed a scoring system based on the expression signatures of RMRP, MIAT, NTT, MALAT1, HSPA1A, and NLRP3 to predict the need for further CAG among patients with moderate-to-significant stress-induced myocardial perfusion defects (area under the receiver operating characteristic curve = 0.963). Therefore, we identified a dysregulated expression profile of lncRNA-based genes in the blood that could be valuable for the early detection of vascular homeostasis imbalance and personalized therapy.

Coronary Volume to Left Ventricular Mass Ratio in Patients With Hypertension

The coronary vascular volume to left ventricular mass (V/M) ratio assessed by coronary computed tomography angiography (CCTA) is a promising new parameter to investigate the relation of coronary vasculature to the myocardium supplied. It is hypothesized that hypertension decreases the ratio between coronary volume and myocardial mass by way of myocardial hypertrophy, which could explain the detected abnormal myocardial perfusion reserve reported in patients with hypertension. Individuals enrolled in the multicenter ADVANCE (Assessing Diagnostic Value of Noninvasive FFRCT in Coronary Care) registry who underwent clinically indicated CCTA for analysis of suspected coronary artery disease with known hypertension status were included in current analysis. The V/M ratio was calculated from CCTA by segmenting the coronary artery luminal volume and left ventricular myocardial mass. In total, 2,378 subjects were included in this study, of whom 1,346 (56%) had hypertension. Left ventricular myocardial mass and coronary volume were higher in subjects with hypertension than normotensive patients (122.7 ± 32.8g vs 120.0 ± 30.5g, p=0.039, and 3,105.0 ± 992.0mm3 vs 2,965.6 ± 943.7mm3, p <0.001, respectively). Subsequently, the V/M ratio was higher in patients with hypertension than those without (26.0 ± 7.6mm3/g vs 25.3 ± 7.3mm3/g, p=0.024). After correcting for potential confounding factors, the coronary volume and ventricular mass remained higher in patients with hypertension (least square) mean difference estimate: 196.3 (95% confidence intervals [CI] 119.9 to 272.7) mm3, p <0.001, and 5.60 (95% CI 3.42 to 7.78) g, p <0.001, respectively), but the V/M ratio was not significantly different (least square mean difference estimate: 0.48 (95% CI -0.12 to 1.08) mm3/g, p=0.116). In conclusion, our findings do not support the hypothesis that the abnormal perfusion reserve would be caused by reduced V/M ratio in patients with hypertension.

Takotsubo syndrome is a coronary microvascular disease: experimental evidence.

Takotsubo syndrome (TTS) is a conundrum without consensus about the cause. In a murine model of coronary microvascular dysfunction (CMD), abnormalities in myocardial perfusion played a key role in the development of TTS. Vascular Kv1.5 channels connect coronary blood flow to myocardial metabolism and their deletion mimics the phenotype of CMD. To determine if TTS is related to CMD, wild-type (WT), Kv1.5-/-, and TgKv1.5-/- (Kv1.5-/- with smooth muscle-specific expression Kv1.5 channels) mice were studied following transaortic constriction (TAC). Measurements of left ventricular (LV) fractional shortening (FS) in base and apex, and myocardial blood flow (MBF) were completed with standard and contrast echocardiography. Ribonucleic Acid deep sequencing was performed on LV apex and base from WT and Kv1.5-/- (control and TAC). Changes in gene expression were confirmed by real-time-polymerase chain reaction. MBF was increased with chromonar or by smooth muscle expression of Kv1.5 channels in the TgKv1.5-/-. TAC-induced systolic apical ballooning in Kv1.5-/-, shown as negative FS (P < 0.05 vs. base), which was not observed in WT, Kv1.5-/- with chromonar, or TgKv1.5-/-. Following TAC in Kv1.5-/-, MBF was lower in LV apex than in base. Increasing MBF with either chromonar or in TgKv1.5-/- normalized perfusion and function between LV apex and base (P = NS). Some genetic changes during TTS were reversed by chromonar, suggesting these were independent of TAC and more related to TTS. Abnormalities in flow regulation between the LV apex and base cause TTS. When perfusion is normalized between the two regions, normal ventricular function is restored.

Prognostic value of combined coronary angiography-derived IMR and myocardial perfusion imaging by CZT SPECT in INOCA

BackgroundA significant proportion of ischemia with non-obstructive coronary artery disease (INOCA) demonstrate coronary microvascular dysfunction (CMD), a condition associated with abnormal myocardial perfusion imaging (MPI) and adverse outcomes. Coronary angiography-derived index of microvascular resistance (caIMR) is a novel non-invasive technique to assess CMD. We aimed to investigate the prognostic value of combined caIMR and MPI by CZT SPECT in INOCA patients. MethodsConsecutive 151 patients with chest pain and < 50% coronary stenosis who underwent coronary angiography and MPI within 3 months were enrolled. caIMR was calculated by computational pressure-flow dynamics. CMD was defined as caIMR ≥ 25. The endpoint was major adverse cardiac events (MACE: cardiovascular death, nonfatal myocardial infarction, revascularization, angina-related rehospitalization, heart failure, and stroke). ResultsOf all INOCA patients, CMD was present in 93 (61.6%) patients. The prevalence of abnormal MPI was significantly higher in CMD compared with non-CMD patients (40.9% vs 13.8%, P < .001). CMD showed a higher risk of MACE than non-CMD patients. Patients with both CMD and abnormal MPI had the worst prognosis, followed by patients with CMD and normal MPI (log-rank P < .001). Cox regression analysis identified CMD (HR 3.121, 95%CI 1.221-7.974, P = .017) and MPI (HR 2.704, 95%CI 1.030-7.099, P = .043) as predictive of MACE. The prognostic value of INOCA patients enhanced significantly by adding CMD and MPI to the model with clinical risk factors (AUC = 0.777 vs 0.686, P = .030). ConclusioncaIMR-derived CMD is associated with increased risk of MACE among INOCA patients. Patients with abnormalities on both caIMR and MPI had the worse outcomes. Graphical abstract▪

Plaque volume, composition, and fraction versus ischemia and outcomes in patients with coronary artery disease

BackgroundThe various plaque components have been associated with ischemia and outcomes in patients with coronary artery disease (CAD). The main goal of this analysis was to test the hypothesis that, at patient level, the fraction of non-calcified plaque volume (PV) of total PV is associated with ischemia and outcomes in patients with CAD. This ratio could be a simple and clinically useful parameter, if predicting outcomes. MethodsConsecutive patients with suspected CAD undergoing coronary computed tomography angiography with selective positron emission tomography perfusion imaging were selected. Plaque components were quantitatively analyzed at patient level. The fraction of various plaque components were expressed as percentage of total PV and examined among patients with non-obstructive CAD, suspected stenosis with normal perfusion, and those with reduced myocardial perfusion. Clinical outcomes included all-cause mortality and myocardial infarction. ResultsIn total, 494 patients (age 63 ​± ​9 years, 55% male) were included. Total PV and all plaque components were significantly larger in patients with reduced myocardial perfusion compared to patients with normal perfusion and those with non-obstructive CAD. During follow-up 35 events occurred. Patients with any plaque component ​≥ ​median showed worse outcomes (log-rank p ​< ​0.001 for all). In addition, low-attenuation plaque ​≥ ​median was associated with worse outcomes independent of total PV (adjusted HR: 2.754, 95% CI: 1.022–7.0419, p ​= ​0.045). The fractions of the various plaque components were not associated with outcomes. ConclusionLarger total PV or any plaque component at patient level are associated with abnormal myocardial perfusion and adverse events. The various plaque components as fraction of total PV lack additional prognostic value.

Microvascular perfusion and cardiac function after revascularization assessed by myocardial contrast echocardiography in patients with acute ST-segment elevation myocardial infarction

Objectives: To evaluate microvascular perfusion and left ventricular function in patients with acute ST-segment elevation myocardial infarction after revascularization using myocardial contrast echocardiography (MCE), and to explore clinical influencing factors of abnormal microvascular perfusion in these patients. Methods: This is a cross-sectional study. The analysis was performed among patients admitted to Peking University People's Hospital for acute ST-segment elevation myocardial infarction (STEMI) from June 2018 to July 2021. All patients underwent percutaneous coronary intervention (PCI) and completed MCE within 48 hours after PCI. Patients were divided into normal myocardial perfusion group and abnormal perfusion group according to the myocardial perfusion score. The echocardiographic indexes within 48 hours after PCI, including peak mitral valve flow velocity (E), mean value of early diastolic velocity of left ventricular septum and lateral mitral annulus (Em), left ventricular global longitudinal strain (GLS) and so on, were analyzed and compared between the two groups. Multivariate logistic regression analysis was used to evaluate the influencing factors of myocardial perfusion abnormalities. Results: A total of 123 STEMI patients, aged 59±13 years with 93 (75.6%) males, were enrolled. There were 50 cases in the normal myocardial perfusion group, and 73 cases in the abnormal myocardial perfusion group. The incidence of abnormal myocardial perfusion was 59.3% (73/123). The left ventricular volume index ((62.3±18.4)ml/m2 vs. (55.1±15.2)ml/m2, P=0.018), wall motion score index (WMSI) (1.59 (1.44, 2.00) vs. 1.24(1.00, 1.47), P<0.001) and mitral E/Em (17.8(12.0, 24.3) vs. 12.2(9.2, 15.7), P<0.001) were significantly higher whereas left ventricular global longitudinal strain (GLS) ((-10.8±3.4)% vs. (-13.8±3.5)%, P<0.001) was significantly lower in the abnormal myocardial perfusion group than those in the normal myocardial perfusion group. Multivariate logistic regression analysis showed that left anterior descending (LAD) as culprit vessel (OR=3.733, 95%CI 1.282-10.873, P=0.016), intraoperative no/low-reflow (OR=6.125, 95%CI 1.299-28.872, P=0.022), and peak troponin I (TnI) (OR=1.018, 95%CI 1.008-1.029, P=0.001) were independent risk factors of abnormal myocardial perfusion. As for ultrasonic indexes, deceleration time of mitral E wave (OR=0.979, 95%CI 0.965-0.993, P=0.003), mitral E/Em (OR=1.100, 95%CI 1.014-1.194, P=0.022) and WMSI (OR=7.470, 95%CI 2.630-21.222, P<0.001) were independently related to abnormal myocardial perfusion. Conclusions: The incidence of abnormal myocardial perfusion after PCI is high in patients with acute STEMI. Abnormal myocardial perfusion is related to worse left ventricular systolic and diastolic function. LAD as culprit vessel, intraoperative no/low-reflow and peak TnI are independent risk factors of abnormal myocardial perfusion.