Coronary Microvascular Obstruction Research Articles

Coronary microvascular obstruction in percutaneous coronary interventions in myocardial infarction patients: a comprehensive approach to prevention and treatment

Coronary microvascular obstruction in percutaneous coronary interventions in myocardial infarction patients: a comprehensive approach to prevention and treatment

To evaluate coronary microvascular obstruction by myocardial contrast echocardiography and its influence on prognosis in patients with ST-segment elevation myocardial infarction

Abstract Background The goal of primary PCI (pPCI) is not only to restore epicardial coronary blood flow quickly but also to provide continuous myocardial tissue level reperfusion through coronary microcirculation. However, the incidence of coronary microvascular obstruction (MVO) after pPCI is as high as 50%-60%, which is closely related to the occurrence of heart failure and increased mortality of patients. Myocardial contrast echocardiography (MCE) is a new noninvasive technique for real-time observation of myocardial microcirculation perfusion in a specific imaging mode. At present, there are few studies on the application of MCE in the evaluation of coronary MVO in STEMI patients in China. Purpose To evaluate coronary MVO by MCE and its influencing factors and prognosis value after pPCI in patients with STEMI. Methods Patients with STEMI who received pPCI from October 2020 to June 2023 in the CCU were enrolled. MCE examination was performed on the 5th to 7th day after pPCI. The patients were divided into the MVO group and Non-MVO group. Major adverse cardiovascular events (MACE) were observed by 6-month follow-up after STEMI onset. Multiple Logistic regression analysis was used to analyze the risk factors for MVO, Multiple Cox regression analysis of the risk factors for MACE and Kaplan-Meier survival curve to compare the cumulative event-free survival of the two groups. Results A total of 98 patients were included in the analysis. The age was 59.88±11.71 years old, and 76(77.55%) were male. MCE examination showed 52 cases in the MVO group and 46 cases in the Non-MVO group. The incidence of MVO was 53.1% (52/98). There were 15 patients with MACE during follow-up. The results of stepwise Multivariate Logistic regression analysis showed that the peak value of cardiac troponin T (cTnT) (OR=1.354,95%CI 1.103-1.661, P=0.004) and without thrombus aspiration (TA) were independent risk factors for MVO (OR=5.588,95%CI 1.915-16.308, P=0.002). Multivariate Cox regression analysis indicated that female (HR=2.891, 95%CI 1.027-8.135, P=0.044), left ventricular ejection fraction (LVEF) <40% (HR=9.960, 95%CI 3.370-29.435, P<0.001) and MVO (HR=5.759,95%CI 1.279-25.935, P=0.023) were independent risk factors for MACE. Kaplan-Meier survival curve showed that the cumulative event-free survival rate in the Non-MVO group was higher than that in the MVO group, and the difference was statistically significant (P=0.0047). Conclusion The incidence of coronary MVO was higher in STEMI patients after pPCI, the peak value of cTnT and without TA were independent risk factors of MVO. The independent risk factors for MACE were female, LVEF < 40%, and MVO.

Mechanism of Coronary Microcirculation Obstruction after Acute Myocardial Infarction and Cardioprotective Strategies.

ST-segment elevation myocardial infarction patients are best treated with emergency percutaneous coronary intervention (PCI), while coronary microvascular dysfunction and obstruction (CMVO) are indicated by the absence or slowing of antegrade epicardial flow on angiography, resulting in suboptimal myocardial perfusion despite the lack of mechanical vascular obstruction. CMVO occurs in up to half of patients who undergo PCI for the first time and is associated with poor outcomes. This review summarizes the complex mechanisms leading to CMVO and elaborates on the changes observed at the organism, tissue, organ, cellular, and molecular levels. It also describes the current diagnostic methods and comprehensive treatment methods for CMVO.

Bailout glycoprotein IIb/IIIa inhibitors for coronary microvascular obstruction: guideline-indicated, but does harm outweigh benefit?

Bailout glycoprotein IIb/IIIa inhibitors for coronary microvascular obstruction: guideline-indicated, but does harm outweigh benefit?

Influence of chronic obstructive pulmonary disease on hospital outcomes of percutaneous coronary interventions in patients with acute coronary syndrome

To evaluate the impact of chronic obstructive pulmonary disease (COPD) on hospital outcomes of percutaneous coronary interventions (PCI) in patients with acute coronary syndrome (ACS). A cohort prospective study of the COPD effect on mortality and coronary microvascular obstruction (CMVO, no-reflow) development after PCI in ACS was carried out. 626 patients admitted in 2019-2020 were included, 418 (67%) - men, 208 (33%) - women. Median age - 63 [56; 70] years. Myocardial infarction with ST elevation identified in 308 patients (49%), CMVO - in 59 (9%) patients (criteria: blood flow <3 grade according to TIMI flow grade; perfusion <2 points according to Myocardial blush grade; ST segment resolution <70%). 13 (2.1%) patients died. Based on the questionnaire "Chronic Airways Diseases, A Guide for Primary Care Physicians, 2005", 2 groups of patients were identified: 197 (31%) with COPD (≥17 points) and 429 (69%) without COPD (<17 points). Groups were compared on unbalanced data (÷2 Pearson, Fisher exact test). The propensity score was calculated, and a two-way logistic regression analysis was performed. The data were balanced by the Kernel "weighting" method, logistic regression analysis was carried out using "weighting" coefficients. Results as odds ratio (OR) and 95% confidence interval. The conducted research allowed us to obtain the following results, depending on the type of analysis: 1) analysis of unbalanced data in patients with COPD: OR death 3.60 (1.16-11.12); p=0.03; OR CMVO 0.65 (0.35-1.22); p=0,18; 2) two-way analysis with propensity score: OR death 3.86 (1.09-13.74); p=0.04; OR CMVO 0.61 (0.31-1.19); p=0.15; 3) regression analysis with "weight" coefficients: OR death 12.49 (2.27-68.84); p=0.004; OR CMVO 0.63 (0.30-1.33); p=0.22. The presence of COPD in patients with ACS undergoing PCI increases mortality and does not affect the incidence of CMVO.

VARIOUS ASPECTS OF PERCUTANEOUS CORONARY INTERVENTIONS AS PREDICTORS OF DEATH IN MYOCARDIAL INFARCTION AND CORONARY MICROVASCULAR OBSTRUCTION (NO-REFLOW)

HighlightsThe review analyzed the role of various preoperative indicators as predictors of long-term mortality in patients with myocardial infarction and coronary microvascular obstruction (no-reflow) that developed during percutaneous coronary intervention. As a result of a multifactorial analysis, taking into account the confounders available for evaluation, we have found that predilation serves as an independent predictor of death within two years. AbstractAim. To evaluate the role of various aspects of percutaneous coronary interventions (PCI) as predictors of long-term death in myocardial infarction (MI) and coronary microvascular obstruction (CMVO, no-reflow).Methods. The unmatched case-control study included 232 patients with type 1 MI and CMVO developed during PCI. CMVO criteria were as follows: TIMI flow grade &lt;3, Myocardial blush grade &lt;2, ST segment resolution after PCI &lt;70%. The “cases” group consisted of 54 (23.3%) patients who died within the next two years, the “controls” group consisted of 178 (76.7%) patients who survived. The analysis included the following indicators: predilation, high-pressure balloon post-dilation, vacuum assisted manual thromboaspiration, intra-aortic balloon pump, intracoronary administration of isosorbide dinitrate and verapamil hydrochloride, glycoprotein IIb/IIIa inhibitors and “potent” p2y12 inhibitors usage, bare-metal stents, stent implantation with exceeded rated burst pressure, 3 or more stents usage, PCI on more than one artery, the ratio of contrast agent volume to glomerular filtration rate (GFR) &gt;3.0. A univariate comparative analysis of the groups regarding PCI aspects and potential confounders was performed (Mann-Whitney, Fisher). To control the confounders, a multivariate analysis was carried out (logistic regression).Results. Differences were obtained for the following indicators: “predilation” – in 51 (94%) patients in the “cases” group and in 139 (78%) in the “control” group, p-value = 0.005; “intra-aortic balloon pump” – in 9 (17%) and 7 (4%) patients respectively, p-value = 0.003; “the ratio of contrast agent volume to GFR &gt;3.0” – in 26 (48%) and 48 (27%) patients, p-value = 0.005. Multivariate analysis revealed that only predilation was an independent predictor of death within two years – odds ratio 7.38 (95% confidence interval 1.70–49.04, p-value = 0.005).Conclusion. Predilation of the infarct-related coronary artery is an independent predictor of death within two years in MI patients who develop CMVO during PCI.

Phenotypes of coronary microvascular obstruction phenomenon (no-reflow) during percutaneous coronary interventions in myocardial infarction

Phenotypes of coronary microvascular obstruction phenomenon (no-reflow) during percutaneous coronary interventions in myocardial infarction

Severity scale of coronary microvascular obstruction (no-reflow) during percutaneous coronary interventions in myocardial infarction patients

Introduction: There is no scale that combines the traditional criteria of coronary microvascular obstruction (CMVO, no-reflow phenomenon) to effectively assess the severity and prognosis of this complication.Objective: To develop and evaluate the severity scale of CMVO during percutaneous coronary intervention (PCI) for myocardial infarction (MI).Methods: The cohort study included 203 patients diagnosed with type 1 MI and CMVO during PCI. The CMVO criterion was TIMI flow grade (TFG) &lt;3 points. Using the proposed "CMVO Severity Scale" (CMVO-SS), three groups of patients were identified. CMVO grade 1 (mild): TFG 2 points, Myocardial blush grade (MBG) 2–3 points, ST segment resolution after PCI (rST) &gt;70%. CMVO grade 2 (moderate): TFG 2 points, MBG 0–1 points or rST &lt;70%. CMVO grade 3 (severe): TFG 0-1 points.Results: Distribution of groups with CMVO of the 1st, 2nd, and 3rd grade is 65 (32%) / 88 (43%) / 50 (25%) patients, respectively. Outcomes by group: acute heart failure grade 3–4 — 2 (3%) / 11 (13%) / 14 (28%), P &lt; .001; ejection fraction — 48 [44; 53] % / 46 [40; 50] % / 42 [39; 49] %, P = .004; in-hospital death — 1 (1.5%) / 12 (13.6%) / 16 (32.0%), P &lt; .001; two-year death — 8 (12.3%) / 19 (21.6%) / 22 (44.0%), P &lt; .001. The multivariate analysis revealed a two-year death odds ratio for the CMVO-SS of 2.40 [95% CI 1.23–5.17], P = .009. Two-year survival probability with CMVO-SS grade 1 was 87.7%, grade 2 — 78.4%, grade 3 — 56.0% (P &lt; .001).Conclusion: The proposed CMVO severity scale is associated with adverse in-hospital outcomes and two-year mortality. Received 15 May 2023. Revised 27 September 2023. Accepted 24 October 2023. Funding: The study was supported by the "Priority 2030" program. Conflict of interest: The authors declare no conflict of interest. Contribution of the authorsConception and study design: A.A. Frolov, E.G. Sharabrin, I.G. PochinkaData collection and analysis: A.A. Frolov, I.A. Frolov, K.V. KuzmichevStatistical analysis: A.A. Frolov, I.A. Frolov, K.V. KuzmichevDrafting the article: A.A. Frolov, I.G. Pochinka, I.A. FrolovCritical revision of the article: I.G. Pochinka, A.S. Mukhin, E.G. Sharabrin, V.N. SinyutinFinal approval of the version to be published: A.A. Frolov, I.G. Pochinka, I.A. Frolov, K.V. Kuzmichev, A.S. Mukhin, E.G. Sharabrin, V.N. Sinyutin

Coronary microvascular obstruction and dysfunction in patients with acute myocardial infarction.

Despite prompt epicardial recanalization in patients presenting with ST-segment elevation myocardial infarction (STEMI), coronary microvascular obstruction and dysfunction (CMVO) is still fairly common and is associated with poor prognosis. Various pharmacological and mechanical strategies to treat CMVO have been proposed, but the positive results reported in preclinical and small proof-of-concept studies have not translated into benefits in large clinical trials conducted in the modern treatment setting of patients with STEMI. Therefore, the optimal management of these patients remains a topic of debate. In this Review, we appraise the pathophysiological mechanisms of CMVO, explore the evidence and provide future perspectives on strategies to be implemented to reduce the incidence of CMVO and improve prognosis in patients with STEMI.

Direct comparison of coronary microvascular obstruction evaluation using CMR feature tracking and layer-specific speckle tracking echocardiography in STEMI patients

PurposeLayer-specific speckle tissue echocardiography (LS-STE) is a unique technique used to assess coronary microvascular obstruction (CMVO) that may offer more information on the myocardial anatomy of patients with ST-elevation myocardial infarction (STEMI). Cardiovascular magnetic resonance feature tracking (CMR-FT) has also been gaining popularity as a way to evaluate CMVO. The aim of the present study was to directly compare CMVO assessment in STEMI patients using CMR-FT and LS-STE.Patients and methodsA total of 105 STEMI patients with LS-STE, CMR-FT, and primary percutaneous coronary intervention (PPCI) were included in the study. Longitudinal peak systolic strain (LS), circumferential peak systolic strain (CS), and radial peak systolic strain (RS) were each used to evaluate CMVO using CMR-FT and LS-STE.ResultsCorrelation coefficients were 0.56, 0.53, and 0.55 for CMR-FT CS vs. endocardial CS, midcardial CS, and epicardial CS comparisons, respectively, and 0.87, 0.51, and 0.32 for CMR-FT LS vs. endocardial LS, midcardial LS, and epicardial LS comparisons, respectively. Bland-Altman analysis revealed strong inter-modality agreement and little bias in endocardial LS, while the absolute of limited of agreement (LOA) value was 2.28 ± 4.48. The absolutes LOA values were 1.26 ± 11.16, -0.02 ± 12.21, and − 1.3 ± 10.27 for endocardial, midcardial, and epicardial respectively. Intraclass correlation coefficient value of 0.87 showed good reliability in endocardial LS, and moderate reliability with values of 0.71, 0.70, and 0.64 in endocardial, midcardial, and epicardial CS, respectively (all p < 0.001).ConclusionsCMR-FT is a viable technique for CMVO evaluation in STEMI patients. Endocardial LS showed good reliability for CMR-FT. STEMI patients can undergo LS-STE to assess the CMVO before PPCI.

Assessment of coronary microcirculation alterations in a porcine model of no-reflow using ultrasound localization microscopy: a proof of concept study.

Coronary microvascular obstruction also known as no-reflow phenomenon is a major issue during myocardial infarction that bears important prognostic implications. Alterations of the microvascular network remains however challenging to assess as there is no imaging modality in the clinics that can image directly the coronary microvascular vessels. Ultrasound Localization Microscopy (ULM) imaging was recently introduced to map microvascular flows at high spatial resolution (∼10μm). In this study, we developed an approach to image alterations of the microvascular coronary flow in exvivo perfused swine hearts. A porcine model of myocardial ischemia-reperfusion was used to obtain microvascular coronary alterations and no-reflow. Four female hearts with myocardial infarction in addition to 6 controls were explanted and placed immediately in a dedicated preservation and perfusion box manufactured for ultrasound imaging. Microbubbles (MB) were injected into the vasculature to perform Ultrasound Localization Microscopy (ULM) imaging and a linear ultrasound probe mounted on a motorized device was used to scan the heart on multiple slices. The coronary microvascular anatomy and flow velocity was reconstructed using dedicated ULM algorithms and analyzed quantitatively. We were able to image the coronary microcirculation of exvivo swine hearts at a resolution of tens of microns and measure flow velocities ranging from 10mm/s in arterioles up to more than 200mm/s in epicardial arteries. Under different aortic perfusion pressures, we measured in large arteries of a subset of control hearts an increase of flow velocity from 31±11mm/s at 87mmHg to 47±17mm/s at 132mmHg (N=3 hearts, P<0.05). This increase was compared with a control measurement with a flowmeter in the aorta. We also compared 6 control hearts to 4 hearts in which no-reflow was induced by the occlusion and reperfusion of a coronary artery. Using average MB velocity and average density of MB per unit of surface as two ULM quantitative markers of perfusion, we were able to detect areas of coronary no-reflow in good agreement with a control anatomical pathology analysis of the cardiac tissue. In the no-reflow zone, we measured an average perfusion of 204±305MB/mm2 compared to 3182±1302MB/mm2 in the surrounding re-perfused area. We demonstrated this approach can directly image and quantify coronary microvascular obstruction and no-reflow on large mammal perfused hearts. This is a first step for noninvasive, quantitative and affordable assessment of the coronary microcirculation function and particularly coronary microvascular anatomy in the infarcted heart. This approach has the potential to be extended to other clinical situations characterized by microvascular dysfunction. This study was supported by the French National Research Agency (ANR) under ANR-21-CE19-0002 grant agreement.

A historical literature review of coronary microvascular obstruction and intra-myocardial hemorrhage as functional/structural phenomena.

The analysis of experimental data demonstrates that platelets and neutrophils are involved in the no-reflow phenomenon, also known as microvascular obstruction (MVO). However, studies performed in the isolated perfused hearts subjected to ischemia/reperfusion (I/R) do not suggest the involvement of microembolization and microthrombi in this phenomenon. The intracoronary administration of alteplase has been found to have no effect on the occurrence of MVO in patients with acute myocardial infarction. Consequently, the major events preceding the appearance of MVO in coronary arteries are independent of microthrombi, platelets, and neutrophils. Endothelial cells appear to be the target where ischemia can disrupt the endothelium-dependent vasodilation of coronary arteries. However, reperfusion triggers more pronounced damage, possibly mediated by pyroptosis. MVO and intra-myocardial hemorrhage contribute to the adverse post-infarction myocardial remodeling. Therefore, pharmacological agents used to treat MVO should prevent endothelial injury and induce relaxation of smooth muscles. Ischemic conditioning protocols have been shown to prevent MVO, with L-type Ca 2+ channel blockers appearing the most effective in treating MVO.

515 ADENOSINE AS ADJUNCTIVE THERAPY IN PATIENTS WITH ACUTE CORONARY SYNDROME: WHEN LESS IS MORE. AN UPDATED META-ANALYSIS OF 26 RANDOMIZED CONTROLLED TRIALS.

Abstract Background Percutaneous coronary intervention (PCI) is the milestone of treatment for patients with acute coronary syndrome (ACS). However, a considerable number of patients do not achieve a complete myocardial reperfusion since coronary microvascular obstruction (CMVO) might occur. Adenosine is one of the pharmacological strategies tested in several randomized controlled trials (RCTs) to minimize the incidence of CMVO. However, conflicting results have been reported so far. The aim of the present study was to evaluate all the RCTs comparing intracoronary or intravenous adenosine versus placebo as adjunctive therapy in patients with ACS undergoing PCI or thrombolysis. Methods PubMed and Scopus electronic databases were scanned for eligible studies up to June 5th, 2022. Our meta-analysis included 26 randomized RCTs with a total of 5843 patients involved. Primary endpoints were the rate of clinical events, defined as major adverse cardiovascular events (MACE), heart failure (HF), all-cause-death and non-fatal myocardial infarction (MI). The rate of advanced atrioventricular (AV) blocks and ventricular fibrillation/sustained ventricular tachycardia (VF/SVT) were considered as safety endpoints. Further subgroup analyses and meta regressions were conducted to evaluate the role of different procedural and non-procedural factors influencing the results. Finally, a secondary analysis was conducted only including RCTs enrolling patients with ST-segment elevation myocardial infarction (STEMI). Results Adenosine administration did not confer any significant clinical benefit in terms of reduction of MACE (RR 0.91 CI 0.79-1.05, p 0.16), all-cause-death (RR 0.90 CI0.74-1.09, p 0.28), non-fatal MI (RR 1 CI 0.74 - 1.35, p 0.44) and HF (RR 0.94 CI 0.77-1.16, p 0.59). Remarkably, adenosine was associated with a significant reduction of post-procedural CMVO parameters such as Myocardial Blush Grade (MBG) 0-1 (RR 0.69 CI 0.53-0.90, p 0.01) and Thrombolysis In Myocardial Infarction (TIMI) flow grade 0-2 (RR 0.67 CI 0.53-0.85, p &amp;lt;0.01), when compared to placebo. Secondary analyses of STEMI patients showed similar results. As regards safety, adenosine therapy was associated with a higher rate of advanced AV blocks (RR 2.72 CI 1.57-4.74, p &amp;lt;0.01). A higher rate of VF/SVT was observed with adenosine in studies with total mean ischemic time &amp;gt;3 hours (RR 1.67 CI 1.14-2.42) Conclusions This is the most up-to-date meta-analysis summarizing the available evidence on adenosine safety and efficacy in the prevention or treatment of CMVO in ACS patients. Although adenosine improves surrogate parameters of myocardial perfusion, its use does not provide any clinical benefits. Additionally, adenosine infusion increases the risk of advanced AV blocks. Moreover, a longer ischemic time seems to be associated with a higher rate of adenosine-triggered ventricular arrhythmias, suggesting that higher myocardial ischemic damage may represent a substrate for adenosine arrhythmogenic effects.

Adenosine as adjunctive therapy in acute coronary syndrome: a meta-analysis of randomized controlled trials.

Adenosine has been tested in several randomized controlled trials (RCTs) to minimize the incidence of coronary microvascular obstruction (CMVO). The aim of this study was to pool all the RCTs comparing intracoronary or intravenous adenosine versus placebo in patients with acute coronary syndrome (ACS) undergoing myocardial revascularization. PubMed and Scopus electronic databases were scanned for eligible studies up to 5th June 2022. A total of 26 RCTs with 5843 patients were included. Efficacy endpoints were major adverse cardiac events (MACE), all-cause death, non-fatal myocardial infarction, and heart failure. Atrioventricular blocks and ventricular fibrillation/sustained ventricular tachycardia (VF/SVT) were the safety endpoints. Myocardial blush grade, thrombolysis in myocardial infarction (TIMI) flow grade, left ventricular ejection fraction (LVEF), infarct size, and ST-segment resolution were also assessed. Adenosine administration was not associated with any clinical benefit in terms of MACE, all-cause death, non-fatal myocardial infarction, and heart failure. However, adenosine was associated with an increased rate of advanced atrioventricular blocks and of VF/SVT in studies with total mean ischaemic time>3h, compared to placebo. Remarkably, among patients undergoing percutaneous coronary intervention, adenosine was associated with reduced myocardial blush grade 0-1 and TIMI flow grade 0-2, compared to placebo. Furthermore, adenosine did not show favourable effects on LVEF and infarct size. Adenosine infusion, as adjunctive therapy in ACS, was associated with an increased risk of advanced atrioventricular blocks and increased rates of adenosine-triggered ventricular arrhythmias in patients with long ischaemic time, without providing any clinical benefit compared to placebo.

The regulation of necroptosis and perspectives for the development of new drugs preventing ischemic/reperfusion of cardiac injury

In the last 10years, mortality from acute myocardial infarction (AMI) has not significantly decreased. This situation is associated with the absence in clinical practice of highly effective drugs capable of preventing the occurrence of reperfusion injury of the heart. Necroptosis inhibitors may become prototypes for the creation of highly effective drugs that increase cardiac tolerance to ischemic/reperfusion (I/R) and reduce the mortality rate in patients with AMI. Necroptosis is involved in I/R cardiac injury and inhibition of RIPK1 or RIPK3 contributes to an increase in cardiac tolerance to I/R. Necroptosis could also be involved in the development of adverse remodeling of the heart. It is unclear whether pre- and postconditioning could inhibit necroptosis of cardiomyocytes and endothelial cells. The role of necroptosis in coronary microvascular obstruction and the no-reflow phenomenon also needs to be studied. MicroRNAs and LncRNAs can regulate necroptotic cell death. Ca2+ overload and reactive oxygen species could be the triggers of necroptosis. Activation of kinases (p38, JNK1, Akt, and mTOR) could promote necroptotic cell death. The interaction of necroptosis, apoptosis, autophagy, ferroptosis, and pyroptosis is discussed. The water-soluble necroptosis inhibitors may be highly effective drugs for treatment of AMI or stroke. It is possible that microRNAs may become the basis for creating drugs for treatment of diseases triggered by I/R of organs.

Comparison of Diagnostic Value Between STE+LDDSE and CMR-FT for Evaluating Coronary Microvascular Obstruction in Post-PCI Patients for STEMI.

BackgroundCoronary microvascular obstruction (CMVO) is closely associated with poor prognosis of ST-segment elevation myocardial infarction (STEMI) patients. However, data showing the comparison between cardiac magnetic resonance feature tracking (CMR-FT) and speckle tracking echocardiography (STE) combined with low-dose dobutamine stress echocardiography (LDDSE) in evaluating CMVO was scarcely available. We aimed to explore and compare the predictive value between CMR-FT and STE+LDDSE in detecting CMVO.MethodsSixty-one STEMI patients were executed cardiac magnetic resonance and echocardiography within the first 5–7 days after primary percutaneous coronary intervention (PCI). The myocardial strain analysis was performed in STE, STE+LDDSE, and CMR-FT, and strain parameters included radial strain (RS), circumferential strain (CS), and longitudinal strain (LS). ROC curves were performed to predict infarcted myocardium segments with CMVO.ResultsFinally, 324 infarcted myocardium segments were analyzed, including 100 infarcted segments with CMVO and 224 segments without CMVO by the gold standard assessment of late gadolinium-enhancement cardiac magnetic resonance imaging (LGE-CMR). The results showed that CS was generally superior to RS and LS in identifying CMVO. CS in CMR-FT facilitated the detection of CMVO, with a sensitivity, specificity, and accuracy of 78.00%, 81.25%, and 80.25%, respectively. The sensitivity, specificity, and accuracy of CS in STE combined with LDDSE were better than STE alone (76.00% vs 60.00%, 79.91% vs 64.29%, and 78.70% vs 62.96%, P < 0.05). In addition, CMR-FT is not superior to STE+LDDSE for detection of CMVO (P > 0.05).ConclusionLow-dose dobutamine can improve the clinical value of STE for evaluating CMVO in STEMI patients. Compared with CMR-FT, STE+LDDSE might be a better choice for STEMI patients because of its safety, convenience, and low-cost.

The evaluation of coronary microvascular obstruction in patients with STEMI by cardiac magnetic resonance T2-STIR image and layer-specific analysis of 2-dimensional speckle tracking echocardiography combined with low-dose dobutamine stress echocardiography.

This study was designed to assess coronary microvascular obstruction (MVO) in patients with acute ST-segment elevation myocardial infarction (STEMI) by cardiac magnetic resonance T2-weighted short tau inversion recovery (T2-STIR) image and layer-specific analysis of 2-dimensional speckle tracking echocardiography combined with low-dose dobutamine stress echocardiography (LDDSE-LS2D-STE). 32 patients were enrolled to perform cardiac magnetic resonance and echocardiography 5-7days after primary percutaneous coronary intervention. Infarcted myocardium was categorized into MVO+ group and MVO- group by late gadolinium enhancement as gold standard. At T2-weighted image, the area of hyper-intense region and hypo-intense core inside were marked as A1, A2 and A2/A1 > 0 represented MVO. Strain parameters were composed of longitudinal strain (LS), circumferential strain and radial strain at rest and dobutamine stress. There were 94 MVO+ segments, 136 MVO- segments according to gold standard. 96 segments had hypo-intense core at T2-STIR image. The sensitivity and specificity of T2-STIR in detecting MVO were 91.49 and 92.65%. Endocardial LS was superior to other parameters, and stress endocardial LS was higher than that of resting endocardial LS (sensitivity: 77.11% vs 72.29%, specificity: 93.28% vs 83.19%, AUC: 0.87 vs 0.82, P < 0.05). The combination of T2-STIR and stress endocardial LS in parallel test could improve sensitivity significantly (98.05% vs 91.49%). T2-STIR has higher diagnostic value in detecting MVO with some limitations. However, LDDSE-LS2D-STE with cost-effective and handling may be a good alternative to T2-STIR. It provides additional and reliable diagnostic tools to identify MVO in STEMI patients after reperfusion.

Development and Validation of a Clinical and Laboratory-Based Nomogram for Predicting Coronary Microvascular Obstruction in NSTEMI Patients After Primary PCI.

ObjectiveCardiac microvascular obstruction (CMVO) remains a severe complication in non-ST elevation myocardial infarction (NSTEMI) patients with reperfusion therapy. We aimed at developing and validating the nomogram to predict the possibility of CMVO after primary percutaneous coronary intervention (PCI) by integrating clinical and laboratory-based information.MethodsA total of 325 patients undergoing primary PCI for NSTEMI were recruited and divided into the training cohort (n=226) and the validating cohort (n = 99). The development of the nomogram was based on independent predictors of CMVO, and these variables were selected by multivariable logistic regression analysis.ResultsIndependent predictors contained in nomogram were identified by multivariable logistic regression analysis, and these independent predictors included neutrophils (OR 1.166, 95% CI 1.044–1.303, P<0.01), hemoglobin (OR 1.037, 95% CI 1.013–1.062, P<0.01), triglyceride (OR 1.343, 95% CI 1.059; 1.704, P=0.015), Killip grade (OR 2.190, 95% CI 1.065–4.503, P=0.033), high thrombus load (OR 3.146, 95% CI 1.424–6.952, P<0.01), no-reflow (OR 3.142, 95% CI 1.419–6.955, P<0.01) and ischemic postconditioning (OR 0.445, 95% CI 0.209–0.944, P=0.035). The nomogram accurately predicted the presentation of CMVO in both the training set and validating set (AUC, 0.835 and 0.881, respectively). The results predicted by nomogram were confirmed to be highly consistent with the results of DE-CMR, both the training and validating cohorts, by Calibration plot and Hosmer-Lemeshow test. Decision curve analysis (DCA) also suggested that the nomogram was applicable in the clinic.ConclusionThe nomogram showed good performance in predicting CMVO, and it could help clinicians optimize the clinical treatments to improve the prognosis of NSTEMI patients.

Using an Artificial Neural Network to Predict Coronary Microvascular Obstruction (No-Reflow Phenomenon) during Percutaneous Coronary Interventions in Patients with Myocardial Infarction.

The aim of the study was to develop, evaluate, and validate an artificial neural network to predict coronary microvascular obstruction (CMVO) during percutaneous coronary interventions (PCI) in patients with myocardial infarctions (MI) based on the parameters, which are routinely available in an operating room when choosing a surgical approach.Materials and Methods5621 patients with MI and emergency PCI were retrospectively selected from the database of the City Clinical Hospital No.13 (Nizhny Novgorod, Russia); among them, there were 3935 men (70%) and 1686 women (30%), their mean age was 61.5±10.8 years. CMVO was recorded in 201 (4%) patients (the blood flow in the infarction-related artery after PCI was less than 3 points according to TIMI flow grade). The following input parameters were assessed: age, gender, past history of coronary artery disease, previous revascularization, presence of ST-segment elevation, a class of acute heart failure, a fact of systemic thrombolytic therapy administration and its effectiveness, symptom-to-balloon time, severity of coronary thrombosis and atherosclerosis, the number of stents and the number of operated coronary arteries. The sampling was divided into a training group (n=4060), a testing group (n=717), and an independent validation group (n=844).ResultsWe developed an artificial neural network by a fully connected multilayer perception with forward signal propagation and two hidden layers (the area under the ROC curve — 0.69) to predict CMVO based on the subsampling for training and testing. The network model was tested on an independent subsampling (the area under the ROC curve — 0.64, negative predictive value — 97.4%, positive predictive value — 14.6%).ConclusionThe developed artificial neural network enables to use the parameters routinely available in an operating room when choosing a surgical approach and predict CMVO development during PCI in MI patients with accuracy sufficient for practical use.

A fresh look at coronary microembolization.

Mechanical stress from haemodynamic perturbations or interventional manipulation of epicardial coronary atherosclerotic plaques with inflammatory destabilization can release particulate debris, thrombotic material and soluble substances into the coronary circulation. The physical material obstructs the coronary microcirculation, whereas the soluble substances induce endothelial dysfunction and facilitate vasoconstriction. Coronary microvascular obstruction and dysfunction result in patchy microinfarcts accompanied by an inflammatory reaction, both of which contribute to progressive myocardial contractile dysfunction. In clinical studies, the benefit of protection devices to retrieve atherothrombotic debris during percutaneous coronary interventions has been modest, and the treatment of microembolization has mostly relied on antiplatelet and vasodilator agents. The past 25 years have witnessed a relative proportional increase in non-ST-segment elevation myocardial infarction in the presentation of acute coronary syndromes. An associated increase in the incidence of plaque erosion rather than rupture has also been recognized as a key mechanism in the past decade. We propose that coronary microembolization is a decisive link between plaque erosion at the culprit lesion and the manifestation of non-ST-segment elevation myocardial infarction. In this Review, we characterize the features and mechanisms of coronary microembolization and discuss the clinical trials of drugs and devices for prevention and treatment.