Relation of coronary flow pattern to myocardial blush grade in patients with first acute myocardial infarction

Accuracy of Post-thrombolysis ST-segment Reduction as an Adequate Reperfusion Predictor in the Pharmaco-Invasive Approach

Fundamento

A intervenção coronária percutânea primária é considerada o “padrão-ouro” para reperfusão coronária. Entretanto, quando não disponível, a estratégia fármaco-invasiva é método alternativo, e o eletrocardiograma (ECG) tem sido utilizado para identificar sucesso na reperfusão.

Objetivos

Nosso estudo teve como objetivo examinar alterações no segmento-ST pós-lise e seu poder de prever a recanalização, usando os escores angiográficos TIMI e blush miocárdio (MBG) como critério de reperfusão ideal.

Métodos

Foram estudados 2.215 pacientes com infarto agudo do miocárdio com supra-ST submetidos à fibrinólise [(Tenecteplase)-TNK] e encaminhados para angiografia coronária em até 24 h pós-fibrinólise ou imediatamente encaminhados à terapia de resgate. O ECG foi realizado pré-TNK e 60 min-pós. Os pacientes foram categorizados em dois grupos: aqueles com reperfusão ideal (TIMI-3 e MBG-3) e aqueles com reperfusão inadequada (fluxo TIMI <3). Foi definido o critério de reperfusão do ECG pela redução do segmento ST >50%. Consideramos p-valor <0,05 para as análises, com testes bicaudais.

Resultados

O critério de reperfusão pelo ECG apresentou valor preditivo positivo de 56%; valor preditivo negativo de 66%; sensibilidade de 79%; e especificidade de 40%. Houve fraca correlação positiva entre a redução do segmento-ST e os dados angiográficos de reperfusão ideal (r = 0,21; p <0,001) e baixa precisão diagnóstica, com AUC de 0,60 (IC-95%; 0,57-0,62).

Conclusão

Em nossos resultados, a redução do segmento-ST não conseguiu identificar com precisão os pacientes com reperfusão angiográfica apropriada. Portanto, mesmo pacientes com reperfusão aparentemente bem-sucedida devem ser encaminhados à angiografia brevemente, a fim de garantir fluxo coronário macro e microvascular adequados.

Microvascular Disease and Small-Vessel Disease: The Nexus of Multiple Diseases of Women

Microvascular disease, or small-vessel disease, is a multisystem disorder with a common pathophysiological basis that differentially affects various organs in some patients. The prevalence of small-vessel disease in the heart has been found to be higher in women compared with men. Additionally, other diseases prominently affecting women, including heart failure with preserved ejection fraction, Takotsubo cardiomyopathy, cerebral small-vessel disease, preeclampsia, pulmonary arterial hypertension (PAH), endothelial dysfunction in diabetes, diabetic cardiomyopathy, rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis, may have a common etiologic linkage related to microvascular disease. To the best of our knowledge this is the first article to investigate this potential linkage. We sought to identify various diseases with a shared pathophysiology involving microvascular/endothelial dysfunction that primarily affect women, and their potential implications for disease management. Advanced imaging technologies, such as magnetic resonance imaging and positron-emission tomography, enable the detection and increased understanding of microvascular dysfunction in various diseases. Therapies that improve endothelial function, such as those used in PAH, may also be associated with benefits across the full spectrum of microvascular dysfunction. A shared pathology across multiple organ systems highlights the need for a collaborative, multidisciplinary approach among medical subspecialty practitioners who care for women with small-vessel disease. Such an approach may lead to accelerated research in diseases that affect women and their quality of life.

Assessment of the relationship between reperfusion success and T-peak to T-end interval in patients with ST elevation myocardial infarction treated with percutaneous coronary intervention

Objective:

T-peak–T-end (TPE) interval, which represents the dispersion of repolarization, is defined as the interval between the peak and end of the T-wave, and is associated with increased malignant ventricular arrhythmia and sudden cardiac death (SCD) in patients with ST elevation myocardial infarction (STEMI). Although prolonged TPE interval is associated with poor short- and long-term outcomes, even in patients with STEMI treated with successful primary percutaneous coronary intervention (pPCI), clinical, angiographic, and laboratory parameters that affect TPE remain to be elucidated. The aim of our study was to evaluate the potential relationship between prolonged TPE interval and reperfusion success using ST segment resolution (STR) in patients with STEMI undergoing pPCI.

Methods:

In the current study, 218 consecutive patients with STEMI who underwent pPCI were enrolled; after exclusion, 164 patients were included in the study population.

Results:

Patients were divided into two groups according to the presence of complete (STR%≥70) or incomplete (STR%<70) STR. Preprocedural corrected TPE (cTPE_PRE;116±21 ms vs. 108±21 ms; p=0.027), postprocedural TPE (TPE_POST; 107±16 ms vs. 92±21 ms; p<0.001), and postprocedural cTPE (cTPE_POST; 119±19 ms vs. 102±17 ms; p<0.001) intervals were significantly longer in patients with incomplete STR than in patients with complete STR, whereas there was no statistically significant difference between the two groups in terms of pre- and postprocedural and corrected QT intervals. cTPE_PRE and cTPE_POST were found to be independent predictors for incomplete STR.

Conclusion:

To our knowledge, this is the first study that evaluated the relationship between TPE interval and no-reflow defined by STR in patients with STEMI who were treated with pPCI.

Targeting the dominant mechanism of coronary microvascular dysfunction with intracoronary physiology tests

The coronary microcirculation plays a key role in modulating blood supply to the myocardium. Several factors like myocardial oxygen demands, endothelial and neurogenic conditions determine its function. Although there is available evidence supporting microvascular dysfunction as an important cause of myocardial ischaemia, with both prognostic and symptomatic implications, its diagnosis and management in clinical practice is still relegated to a second plane. Both diagnostic and therapeutic approaches are hampered by the broadness of the concept of microvascular dysfunction, which fails addressing the plurality of mechanisms leading to dysfunction. Normal microcirculatory function requires both structural integrity of the microcirculatory vascular network and preserved signalling pathways ensuring adequate and brisk arteriolar resistance shifts in response to myocardial oxygen demands. Pathological mechanisms affecting these requirements include structural remodelling of microvessels, intraluminal plugging, extravascular compression or vasomotor dysregulation. Importantly, not every diagnostic technique provides evidence on which of these pathophysiological mechanisms is present or predominates in the microcirculation. In this paper we discuss the mechanisms of coronary microvascular dysfunction and the intracoronary tools currently available to detect it, as well as the potential role of each one to unmask the main underlying mechanism.

Relationship between R-wave peak time and no-reflow in ST elevation myocardial infarction treated with a primary percutaneous coronary intervention

OBJECTIVES

Coronary no-reflow (NR) is observed in nearly half of ST segment elevation myocardial infarction (STEMI) patients who undergo a primary percutaneous coronary intervention (pPCI) despite epicardial coronary vessel patency. Several methods used to define NR include thrombolysis in myocardial infarction grade, corrected thrombolysis in myocardial infarction frame count, myocardial blush grade, ST-segment resolution, contrast echocardiography, and MRI. The aim of our study was to evaluate the relationship between NR and R-wave peak time (RWPT) measured from infarct-related artery leads METHOD: We enrolled 282 consecutive STEMI patients treated with pPCI in Kafkas University Hospital from January 2014 to January 2015. After exclusion, the remaining 233 patients were included in the study population RESULTS: Patients were divided into two groups according to the development of NR. We observed that increased preprocedural (31 (27-37) vs 27 (21-30) p<0,001) and postprocedural RWPT(35±7 vs 22±6 p<0,001) was associated with the development of NR and preprocedural RWPT(OR: 1.254 95% CI: 1.104-1.425 p<0,001) was found to be independent predictor of NR. The association between postprocedural RWPT and angiographic NR was statistically noninferior to that between ST-segment resolution % and NR(difference between area under curves: 0.0232, p= 0.38) CONCLUSION: the present study is the first to report a significant correlation between NR and RWPT in STEMI patients treated with primary pPCI.

Intracoronary Eptifibatide During Primary Percutaneous Coronary Intervention in Early Versus Late Presenters with ST Segment Elevation Myocardial Infarction: A Randomized Trial

INTRODUCTION

The role of intracoronary (IC) eptifibatide in primary percutaneous coronary intervention (PPCI) for ST segment elevation myocardial infarction (STEMI) and whether time of patient presentation affects this role are unclear. We sought to evaluate the benefit of IC eptifibatide use during primary PCI in early STEMI presenters compared to late STEMI presenters.

METHODS

We included 70 patients who presented with STEMI and were eligible for PPCI. On the basis of symptom-to-door time, patients were classified into two arms: early (<3 h, n = 34) vs late (≥3 h, n = 36) presenters. They were then randomized to local IC eptifibatide infusion vs standard care (control group). The primary end point was post-PCI myocardial blush grade (MBG) in the culprit vessel. Other end points included corrected TIMI frame count (cTFC), ST segment resolution (STR) ≥70%, and peak CKMB.

RESULTS

In the early presenters arm, no difference was observed in MBG results ≥2 in the IC eptifibatide and control groups (100% vs 82%; p = 0.23). In the late presenters arm, the eptifibatide subgroup was associated with improved MBG ≥2 (100% vs 50%; p = 0.001). IC eptifibatide in both early and late presenters was associated with less cTFC (early presenters 19 vs. 25.6, p = 0.001; late presenters 20 vs. 31.5, p < 0.001) and less peak CKMB (early presenters 210 vs 260 IU/L, p = 0.006; late presenters 228 vs 318 IU/L, p = 0.005) compared with the control group. No difference existed between both groups in STR index in early and late presenters.

CONCLUSION

IC eptifibatide might improve the reperfusion markers during PPCI for STEMI patients presenting after 3 h from onset of symptoms. A large randomized study is recommended to ascertain the benefits of IC eptifibatide in late presenters on clinical outcomes.

Coronary arterial BK channel dysfunction exacerbates ischemia/reperfusion-induced myocardial injury in diabetic mice

The large conductance Ca(2+)-activated K(+) (BK) channels, abundantly expressed in coronary artery smooth muscle cells (SMCs), play a pivotal role in regulating coronary circulation. A large body of evidence indicates that coronary arterial BK channel function is diminished in both type 1 and type 2 diabetes. However, the consequence of coronary BK channel dysfunction in diabetes is not clear. We hypothesized that impaired coronary BK channel function exacerbates myocardial ischemia/reperfusion (I/R) injury in streptozotocin-induced diabetic mice. Combining patch-clamp techniques and cellular biological approaches, we found that diabetes facilitated the colocalization of angiotensin II (Ang II) type 1 receptors and BK channel α-subunits (BK-α), but not BK channel β1-subunits (BK-β1), in the caveolae of coronary SMCs. This caveolar compartmentation in vascular SMCs not only enhanced Ang II-mediated inhibition of BK-α but also produced a physical disassociation between BK-α and BK-β1, leading to increased infarct size in diabetic hearts. Most importantly, genetic ablation of caveolae integrity or pharmacological activation of coronary BK channels protected the cardiac function of diabetic mice from experimental I/R injury in both in vivo and ex vivo preparations. Our results demonstrate a vascular ionic mechanism underlying the poor outcome of myocardial injury in diabetes. Hence, activation of coronary BK channels may serve as a therapeutic target for cardiovascular complications of diabetes.

No reflow phenomenon in percutaneous coronary interventions in ST-segment elevation myocardial infarction

Percutaneous coronary intervention (PCI) is effective in opening the infarct related artery and restoring thrombolysis in myocardial infarction flow 3 (TIMI-flow 3) in large majority of ST-elevation myocardial infarction (STEMI). However there remain a small but significant proportion of patients, who continue to manifest diminished myocardial reperfusion despite successful opening of the obstructed epicardial artery. This phenomenon is called no-reflow. Clinically it manifests with recurrence of chest pain and dyspnea and may progress to cardiogenic shock, cardiac arrest, serious arrhythmias and acute heart failure. No reflow is regarded as independent predictor of death or recurrent myocardial infarction. No reflow is a multi-factorial phenomenon. However micro embolization of atherothrombotic debris during PCI remains the principal mechanism responsible for microvascular obstruction. This review summarizes the pathogenesis, diagnostic methods and the results of various recent randomized trials and studies on the prevention and management of no-reflow.

The increased cardiovascular risk in patients affected by autoimmune diseases: review of the various manifestations

Cardiovascular and autoimmune diseases are among major health concerns in developed countries, and both represent a significant source of morbidity, mortality and economic costs. Despite they are thought to affect subjects at different ages, most of the deaths of patients affected by autoimmune diseases are represented by cardiovascular deaths. Several manifestations of cardiovascular diseases can be observed in patients with autoimmune diseases, such as endothelial dysfunction, accelerated atherosclerosis and an increase in the rate of acute coronary syndromes. Thus, people with autoimmune diseases have an increased cardiovascular risk and a worse outcome in the case of cardiovascular events. In this review, we will describe the correlations between the two spectra of diseases.

Thrombus aspiration in acute myocardial infarction: Rationale and indication

Reperfusion of myocardial tissue is the main goal of primary percutaneous coronary intervention (PPCI) with stent implantation in the treatment of acute ST-segment elevation myocardial infarction (STEMI). Although PPCI has contributed to a dramatic reduction in cardiovascular mortality over three decades, normal myocardial perfusion is not restored in approximately one-third of these patients. Several mechanisms may contribute to myocardial reperfusion failure, in particular distal embolization of the thrombus and plaque fragments. In fact, this is a possible complication during PPCI, resulting in microvascular obstruction and no-reflow phenomenon. The presence of a visible thrombus at the time of PPCI in patients with STEMI is associated with poor procedural and clinical outcomes. Aspiration thrombectomy during PPCI has been proposed to prevent embolization in order to improve these outcomes. In fact, the most recent guidelines suggest the routine use of manual aspiration thrombectomy during PPCI (class IIa) to reduce the risk of distal embolization. Even though numerous international studies have been reported, there are conflicting results on the clinical impact of aspiration thrombectomy during PPCI. In particular, data on long-term clinical outcomes are still inconsistent. In this review, we have carefully analyzed literature data on thrombectomy during PPCI, taking into account the most recent studies and meta-analyses.

Assessment of coronary artery flow velocity pattern as a long-term predictor of left ventricular function and cardiac events after percutaneous coronary intervention in anterior acute myocardial infarction

BACKGROUND

Coronary flow velocity (CFV) can be used to assess short-term left ventricular function recovery and the clinical prognosis of patients with acute myocardial infarction (AMI). We evaluated CFV as a predictor of long-term left ventricular function recovery and cardiac events in patients with anterior wall AMI.

METHODS AND RESULTS

CFV pattern of the distal left anterior descending (LAD), wall motion score index (WMSI) and left ventricular ejection fraction (LVEF) were recorded at the points of time within 24 hours, 3 days, 6 months, and 3 years after percutaneous coronary intervention (PCI) in 50 consecutive patients with anterior wall AMI. The clinical data were collected. Patients were divided into two groups based on diastolic deceleration time (DDT) 3 days after PCI. Compared with 3 days, LVEF and WMSI in group A (DDT>600 ms, n=20) improved in 6 months and 3 years (p<0.01), but they were unchanged in group B (DDT< or =600 ms, n=30). The incidence of cardiac events was higher in group B than in group A during 6 months (p<0.01).With a 3-year follow up, the incidence of chronic heart failure was higher in group B than in group A (p=0.009).

CONCLUSION

CFV could be used as a predictor of long-term left ventricular function recovery and cardiac events in patients with anterior wall AMI.

Relationship between microvascular resistance and perfusion in patients with reperfused acute myocardial infarction

Despite its prognostic importance, accurate assessment of microvascular perfusion in patients with ST elevation acute myocardial infarction (STEMI) is difficult. As a new tool, the index of microvascular resistance (IMR) measurement provides us a new opportunity for interrogating microvascular condition after STEMI. In this study, we measured IMR in infarct-related artery (IRA) and explored its relation with other indices which have been suggested to evaluate microvascular perfusion in patients with reperfused STEMI.

METHODS

Forty-two patients with STEMI treated successfully with primary percutaneous coronary intervention (pPCI) were prospectively included. After 48 hours following pPCI, patients were recatheterized and IMR, coronary flow reserve (CFR), systolic and mean coronary wedge pressures (CWPs and CWPm) pressure-derived collateral flow index (CFIp) were measured in IRA by using intracoronary pressure-temperature sensor tipped guide wire. Myocardial blush grade was assessed from the second angiogram. Coronary flow velocity pattern (diastolic deceleration time: DDT) was examined with transthoracic echocardiography 48 hours after pPCI. Percentage of ST-segment recovery was calculated from surface ECG (STR%).

RESULTS

IMR well correlated with CWPs (r = 0.70, P < 0.001), CWPm (r = 0.59, P < 0.001), CFIp (r = 0.65, P < 0.001), CFR (r =-0.50, P = 0.001), and DDT (r =-0.59, P = 0.001). Correlations of IMR to non/semiinvasive indices like myocardial blush grades (MBG) (r =-0.42, P = 0.007) and STR (r =-0.37, P = 0.024) are somewhat weaker.

CONCLUSION

Given its simplicity of measurement, independence from the presence of an epicardial stenosis, and good correlation with all measures of microvascular obstruction used in this study, IMR may prove to be a valuable modality for evaluating the microcirculation.

Myocardial perfusion in apical ballooning syndrome correlate of myocardial injury

BACKGROUND

The pathophysiology of the apical ballooning syndrome (ABS) is poorly understood. This study evaluated myocardial perfusion abnormalities at the time of presentation in patients with ABS and examined whether abnormal microvascular blood flow predicts the extent of myocardial injury.

METHODS

We evaluated 42 consecutive patients, all women, with a diagnosis of ABS and technically adequate angiograms for the assessment of the TIMI myocardial perfusion grade (TMPG), an index of myocardial perfusion.

RESULTS

Abnormal myocardial perfusion was present in 29 (69%) patients. There were no differences in age, frequency of conventional coronary atherosclerosis risk factors, left ventricular ejection fraction at either presentation or follow-up, congestive heart failure at presentation, or length of hospital stay between patients with normal versus those with abnormal TMPG. Patients with abnormal TMPG had higher peak troponin level compared with patients with normal TMPG (0.84 +/- 0.68 vs 0.42 +/- 0.33 ng/mL, P = .047). Similarly, ST elevation or deep T-wave inversion on the electrocardiogram was more common in patients with abnormal perfusion (86% vs 46%, P = .006).

CONCLUSION

Impaired myocardial perfusion due to abnormal microvascular blood flow is frequently present in patients with ABS and correlates with the extent of myocardial injury. Microvascular dysfunction likely play a pivotal role in the pathogenesis of myocardial stunning in ABS.

Pressure-derived collateral flow index: a strong predictor of late left ventricular remodeling after thrombolysis for acute myocardial infarction

OBJECTIVE

Despite proved efficacy of pressure-derived collateral flow index in determining microvascular dysfunction in patients with acute myocardial infarction, its role in prediction of left ventricular remodeling at long term has yet to be demonstrated. In this study, we investigated the relationship between quantitatively assessed microvascular dysfunction by using intracoronary pressure wire and late left ventricular remodeling.

PATIENTS AND METHODS

The study population consisted of 28 patients with first acute myocardial infarction. They were treated with fibrinolytic therapy. The inclusion criteria were thrombolysis in myocardial infarction grade II-III flow in infarct-related artery and all destined for stent implantation. Cardiac catheterization and stent implantation were performed in mean of 3.3 days after acute myocardial infarction. During the stent implantation procedure, the pressure-derived collateral flow index was measured by using intracoronary pressure wire. Control angiograms were performed at 6+/-2 months. Echocardiographic left ventricular volume indexes were measured at discharge, at 6 months and at 1 year. Changes in left ventricular volumes from baseline to 1 year were followed.

RESULTS

Left ventricular end-diastolic volume index at 1 year correlated significantly with the pressure-derived collateral flow index (r=0.69, P<0.01). A significant correlation was also observed between the change in left ventricular end-diastolic volume index from baseline to 1 year and the pressure-derived collateral flow index (r=0.65, P<0.01). The most important predictor of 1-year left ventricular remodeling was the pressure-derived collateral flow index (P<0.0001), and collateral circulation (P=0.03).

CONCLUSION

The pressure-derived collateral flow index is a powerful independent predictor of 1-year left ventricular dilatation. Given its simplicity of measurement, and correlation with microvascular obstruction and left ventricular outcome at long term, the pressure-derived collateral flow index may provide useful and valuable estimates of clinical outcomes after acute myocardial infarction.

Plain Computed Tomography for Assessment of Early Coronary Microcirculatory Damage After Revascularization Therapy in Acute Myocardial Infarction

BACKGROUND

Coronary microcirculatory damage is an important factor for the prognosis for acute myocardial infarction (MI) after revascularization. The myocardial enhancement area with contrast media infused during coronary revascularization therapy, detected by computed tomography (CT) just after revascularization, has been reported to correspond to the area of hemorrhagic infarction. The relationship between myocardial contrast enhancement and coronary microcirculatory damage was investigated in the present study.

METHODS AND RESULTS

Thirteen patients with acute anterior MI underwent successful coronary revascularization within 6 h of symptom onset were enrolled. The coronary flow velocity pattern was measured using a Doppler guidewire and chest CT assessments were performed immediately after coronary revascularization. The ratio of mean CT number of the highest-enhanced myocardial area and the lumen of the left ventricle was defined as a relative CT number. The relative CT number significantly correlated with coronary diastolic deceleration time (r=-0.78, p<0.002) and coronary diastolic deceleration rate (r=0.74, p<0.04). It also correlated with peak myocardial enzyme release in plasma.

CONCLUSION

Myocardial contrast enhancement detected using plain CT just after coronary reperfusion therapy implies coronary microcirculatory damage in acute MI. The relative CT number is useful in evaluating the impaired coronary microcirculatory state.

Impact of diabetes mellitus on myocardial perfusion after primary angioplasty in patients with acute myocardial infarction

OBJECTIVES

We investigated the impact of diabetes mellitus on myocardial perfusion after primary percutaneous coronary intervention (PCI) utilizing myocardial blush grade (MBG) and ST-segment elevation resolution (STR).

BACKGROUND

Diabetes is an independent predictor of outcomes after primary PCI for acute myocardial infarction (AMI). Whether the poor prognosis is due to lower rates of myocardial reperfusion is unknown.

METHODS

Reperfusion success in those with and without diabetes mellitus was determined by measuring MBG (n = 1,301) and STR analysis (n = 700) in two substudies of the Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) trial among patients undergoing primary PCI for AMI.

RESULTS

There were no differences between those with or without diabetes with regard to postprocedural Thrombolysis In Myocardial Infarction (TIMI) flow grade 3 (>95%), distribution of infarct-related artery, and the frequency of stent deployment or abciximab administration. Patients with diabetes mellitus were more likely to have absent myocardial perfusion (MBG 0/1, 56.0% vs. 47.1%, p = 0.01) and absent STR (20.3% vs. 8.1%, p = 0.002). Diabetes mellitus (hazard ratio [HR] 1.63 [95% confidence interval (CI) 1.17 to 2.28], p = 0.004) was an independent predictor of absent myocardial perfusion (MBG 0/1) and absent STR (HR 2.94 [95% CI 1.64 to 5.37], p = 0.005) by multivariate modeling.

CONCLUSIONS

Despite similar high rates of TIMI flow grade 3 after primary PCI in patients with and without diabetes, patients with diabetes are more likely to have abnormal myocardial perfusion as assessed by both incomplete STR and reduced MBG. Diminished microvascular perfusion in diabetics after primary PCI may contribute to adverse outcomes.