ABSTRACT
AIMS: Two-dimensional speckle tracking echocardiography (2DSTE) detects early signs of left ventricular dysfunction; however, it is unknown whether layer-specific global longitudinal strain (GLS) has incremental value in diagnosis of patients with reversible ischemia assessed by single photon emission computed tomography (SPECT). METHODS AND RESULTS: Eighty patients with stable angina pectoris (SAP), normal left ventricular ejection fraction (LVEF), and no history of ischemic heart disease were retrospectively identified to have been examined by 2DSTE, SPECT, and coronary angiography (CAG). Patients with a normal SPECT constituted the control group, and patients with a positive SPECT were divided into patients with or without (true- or false- positive SPECT) significant stenosis assessed by CAG. GLS was measured for two myocardial layers (endocardial and epicardial) and as well as mid-myocardial GLS. Patients with reversible ischemia had significantly lower GLS compared to the control group (GLSEndocardial : -19.0 ± 4.4% vs -21.4 ± 3.7%, P = .011; GLSEpicardial : -14.3 ± 2.9% vs -16.3 ± 2.9%, P = .004); GLSMid-myocardial : -16.5 ± 3.6% vs -18.6 ± 3.2%, P = .006. This difference was even more evident in patients with a true-positive SPECT (GLSEndocardial : -18.0 ± 4.4% vs -21.4 ± 3.7%, P < .001; GLSEpicardial : -13.6 ± 3.0% vs -16.3 ± 2.9%, P < .001); GLSMid-myocardial : -15.6 ± 3.6% vs -18.6 ± 3.2%, P < .001. Notably, no significant differences existed in patients with a false-positive SPECT. GLSEpicardial was the only independent predictor of coronary artery disease. IN CONCLUSION: In patients with SAP and preserved LVEF, layer-specific GLS at rest identifies patients with reversible ischemia. This seems to be evident only in patients with a true-positive SPECT, thus, 2DSTE at rest might improve the diagnostic accuracy of a positive SPECT.
Subject(s)
Echocardiography, Doppler, Color/methods , Echocardiography, Three-Dimensional/methods , Heart Ventricles/diagnostic imaging , Myocardial Contraction/physiology , Myocardial Ischemia/complications , Tomography, Emission-Computed, Single-Photon/methods , Ventricular Dysfunction, Left/physiopathology , Aged , Coronary Angiography , Electrocardiography , Female , Follow-Up Studies , Heart Ventricles/physiopathology , Humans , Male , Middle Aged , Myocardial Ischemia/diagnosis , Myocardial Ischemia/physiopathology , ROC Curve , Retrospective Studies , Ventricular Dysfunction, Left/diagnosis , Ventricular Dysfunction, Left/etiologyABSTRACT
Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1) identification of the extent of a multivessel coronary artery disease (CAD) burden, 2) patients with balanced 3-vessel CAD, 3) patients with subclinical CAD, and 4) patients with regional flow variance, despite of a high global MFR. A more accurate assessment of the ischemic burden in patients with intermediate pretest probability of CAD can support the clinical decision-making in treatment of CAD patients as a complementary tool to the invasive coronary angiography (CAG). Recently, several studies have proven Rubidium-82 ((82)Rb) PET's long-term prognostic value by a significant association between compromised global MFR and major adverse cardiovascular events (MACE), and together with new diagnostic possibilities from measuring the longitudinal myocardial perfusion gradient, cardiac (82)Rb PET faces a promising clinical future. This article reviews current evidence on quantitative (82)Rb PET's ability to diagnose and risk stratify CAD patients, while assessing the potential of the modality in clinical practice.
