The value of the TIMI frame count method in the diagnosis of coronary no-reflow: a comparison with myocardial perfusion SPECT in patients with acute myocardial infarction

The Effects of Percutaneous Coronary Intervention on the Flow in Acute Coronary Syndrome Patients-Geometry in Focus

Evaluation of the effect of three dimensional (3D) coronary plaque characteristics derived from two dimensional (2D) invasive angiography images (ICA) on coronary flow determined by TIMI frame count (TFC) in acute coronary syndrome (ACS) has not been thoroughly investigated. A total of 71 patients with STEMI, and 73 with NSTEMI were enrolled after primary angioplasty. Pre- and post-PCI TFCs were obtained. From 2D images, 3D reconstruction was performed of the culprit vessel, and multiple plaque parameters were measured. In STEMI, the average post-PCI frame count decreased significantly, resulting in better flow. With regards to 2/3D parameters, no differences were found between the STEMI and NSTEMI groups. The 3D parameters in the subgroup with an increase with at least three frames resulting in worsening post-PCI flow were compared to parameters of the patients with improved or significantly not change flow (delta frame count < 3), and greater minimal luminal diameter and area was found in the worsening (increased) frame group. In STEMI 2/3D, parameters showed no correlation with worsening flow, whereas in NSTEMI, greater minimal luminal diameter and area correlated with decreased flow. We can conclude that certain 2/3D parameters can predict slower flow in ACS, resulting in the use of GP IIb/IIIa receptor blocker.

Imaging the myocardial microcirculation post-myocardial infarction

The myocardial microcirculation provides the vital pressure control and metabolic homeostasis for normal muscle function. Microvascular dysfunction is implicated in chronic cardiac disease and can signify higher risk, but its effect in acute myocardial infarction (AMI) can be profound. Modern management of AMI is focussed entirely on timely epicardial coronary patency, but as a result can leave microcirculatory devastation in its wake. The 'no-reflow' phenomenon occurs in up to 40 % of those successfully reperfused following an ST-elevation AMI (STEMI), and reflects significant microvessel injury that at its most severe involves both microvascular obstruction (MVO) and intramyocardial haemorrhage. Myocardial contrast echocardiography and cardiac magnetic resonance imaging have both led the field in establishing MVO as the prime determinant of adverse left ventricular (LV) remodeling, LV dysfunction, heart failure and increased mortality. These imaging techniques will be essential to support future research endeavours and shift focus to the maintenance of microvascular flow in AMI.

Angiographic assessment of microvascular perfusion--myocardial blush in clinical practice

Assessment of myocardial "blush" by either Myocardial Blush Grade or TIMI Myocardial Perfusion Grade, is the angiographic method currently preferred to confirm myocardial tissue-level perfusion after primary percutaneous intervention. This review focuses on the utility of angiographic "blush" as a simple, widely available, and virtually costless technique for the immediate diagnosis of microvascular impairment at the time of acute catheterization. We comprehensively outline the available evidence behind the "blush," its use in clinical practice, and draw comparisons with other new technologies for assessment of microvascular integrity.

Prediction of the no-reflow phenomenon during percutaneous coronary intervention using coronary computed tomography angiography

Coronary computed tomography angiography (CTA) can assess plaque characteristics and plaque size noninvasively. The purpose of this study was to investigate whether coronary CTA before percutaneous coronary intervention (PCI) can predict the no-reflow phenomenon during PCI. Seventy-eight patients [acute coronary syndrome (ACS) = 43, stable angina pectoris (SAP) = 35, male/female = 72/6, age: 65 ± 10 years] who underwent 16- or 64-slice CTA in the 4 weeks before PCI were enrolled. The low attenuation plaque size on CTA was compared between patients with (NR+) and without the no-reflow phenomenon (NR-). No-reflow phenomenon was observed in 11 patients, including 10 patients with ACS and 1 patient with SAP. Low attenuation plaque was detected in 9 (82%) NR(+) lesions and 35 (52%) NR(-) lesions. The length of low attenuation plaque was significantly longer in NR(+) than in NR(-) patients (9.0 ± 6.5 vs. 1.6 ± 2.7 mm, p < 0.0001). On step-wise regression analysis, ACS (p = 0.036, 95% CI = 0.009-0.258) and the presence of low attenuation plaque with a length >4.7 mm (p < 0.001, 95% CI = 0.447-0.778) were significant independent predictors of NR(-) no-reflow phenomenon. Low attenuation plaque with lesion length of >4.7 mm on coronary CTA and ACS were the significant predictors for the no-reflow phenomenon during PCI. Coronary CTA assessment before PCI would be useful to predict coronary events during PCI in advance.

Clinical and procedural predictors of no-reflow phenomenon after primary percutaneous coronary interventions: experience at a single center

BACKGROUND

The aim of the study was to identify clinical factors, angiographic findings, and procedural features that predict no-reflow phenomenon (Thrombolysis In Myocardial Infarction (TIMI) flow grade < or =2) in patients with acute myocardial infarction (AMI) who undergo primary percutaneous coronary intervention (PCI).

METHODS AND RESULTS

A series of 382 consecutive patients with AMI underwent primary PCI within 12 h of symptom onset. Patients with ischemic symptoms continuing for more than 12 h were also included. Clinical, angiographic and procedural data were collected for each subject. Ninety-three (24.3%) of the patients developed no-reflow phenomenon, and their findings were compared with those of the reflow group. Univariate analysis showed that advanced age (>60 years), delayed reperfusion (> or =4 h), low (< or =1) TIMI flow prior to PCI, cut-off type total occlusion, high thrombus burden on baseline angiography, long target lesion (>13.5 mm) and large vessel diameter all correlated with no-reflow (p<0.05 for all). Multiple logistic regression analysis identified that advanced age (odds ratio (OR) 1.04, p=0.001), delayed reperfusion (OR 1.4, p=0.0004), low TIMI flow before primary PCI (OR 1.1, p=0.0002), target lesion length (OR 5.1, p=0.0003) and high thrombus burden (OR 1.6, p=0.03) on angiography as independent predictors of no-reflow phenomenon.

CONCLUSION

The occurrence of no-reflow phenomenon after primary PCI can be predicted using simple clinical, angiographic and procedural features. In this selected group of patients, adjunctive pharmacotherapy and/or distal protection device may be of value.

Use of the TIMI frame count in the assessment of coronary artery blood flow and microvascular function over the past 15 years

Since its introduction, the TIMI frame count method has contributed to the understanding of the pathophysiology of coronary artery disease. In this article, the evolution of the TFC method and its applicability in the assessment of various therapeutic modalities are described.

Current assessments of the adequacy of myocardial perfusion during acute MI

For two decades now, the optimal management of acute coronary syndrome has been the early restoration of complete and sustained flow to the jeopardized infarct area. Advances in thrombolytic therapy and percutaneous coronary interventions have contributed significantly to the re-establishment of epicardial flow. However, a body of evidence now strongly indicates that restoration of epicardial flow alone is not sufficient to optimize clinical outcomes. Rather, it has become evident that reperfusion therapy must also involve restoration of microcirculatory reperfusion. Thus, techniques to assess myocardial perfusion during acute myocardial infarction are becoming increasingly relevant for the assessment of patient prognosis.

Myocardial Reperfusion: Its Assessment and Its Relation to Clinical Outcomes

It has become increasingly apparent that epicardial blood flow restoration is necessary, but not sufficient, to achieve optimal clinical outcomes in the setting of acute coronary syndromes. Indeed, clinical outcomes are strongly associated with myocardial perfusion. The diagnostic tools available to assess myocardial perfusion following acute myocardial infarction and their association with clinical outcomes are reviewed here. Many simple angiographic markers--the Thrombolysis in Myocardial Infarction (TIMI) count frame, TIMI myocardial perfusion grade, pulsatile flow--are all readily available measures and are strongly related to clinical outcomes. Other tools, while accurate, remain limited by their high cost, low availability, and complexity for routine use.