Discover the EACVI Textbook of Echocardiography 2nd edition
Chapter 15 Stress echocardiography: diagnostic and prognostic values and specific clinical subsets Luc A. Pierard and Lauro Cortigiani Contents Summary 104 Diagnostic and prognostic values 104 Viability 104 Myocardial ischaemia 104 Limited coronary flow reserve 106 Diagnostic flowcharts 106 Specific clinical subsets 107 Women 107 Left bundle branch block 107 Hypertensive patients 107 Diabetic patients 108 Non-cardiac vascular surgery 108 Valvular heart disease 108 Hypertrophic cardiomyopathy 108 Conclusion 108 References 108 Summary Stress echocardiography (SE) combines two- (2D) or three-dimensional (3D) echocardiography with a physical (exercise) or pharmacological (inotropic or vasodilator) stress for assessing the presence, localization, and extent of myocardial ischaemia. Identification of viable myocardium and evaluation of haemodynamic repercussions and the dynamic component of valvular heart disease are additional recognized applications of SE. Diagnostic and prognostic values Viability In patients with dysfunctional but viable myocardium, regional function can be improved by the inotropic effect of dobutamine. In patients with ischaemic cardiomyopathy, sensitivity and specificity of dobutamine SE are 84% and 81% respectively for predicting functional recovery following revascularization and the technique provides lower sensitivity, but higher specificity and similar accuracy than myocardial perfusion imaging (MPI) . In addition, the documentation of a large amount of viable myocardium (at least four segments or 20% of the total left ventricle) on dobutamine SE predicts improved ejection fraction , reverse remodelling , and markedly lower mortality rate in revascularized than in medically treated patients [4,5] (% Fig. 15.1), independently of a history of diabetes . However, these findings do not apply to patients with high end-systolic volume, presenting modest change in ejection fraction and poor outcome after revascularization independently of the presence of tissue viability . Myocardial ischaemia Stress-induced wall motion abnormality is an early and specific marker of ischaemia. In a meta-analysis on 3714 patients, exercise, dobutamine, and dipyridamole SE showed a sensitivity, respectively, of 83%, 81%, and 72%, and a specificity of 84%, 84%, and 95% . Anti-ischaemic therapy lowers sensitivity of both exercise and pharmacological SE . However, it lowers the sensitivity of dipyridamole more than that of dobutamine . Compared to MPI, SE has similar accuracy, with a moderate sensitivity gap that is balanced by a markedly higher specificity . The results of studies enrolling thousands of
Chapter 16 Lung ultrasound Luna Gargani and Marcelo-Haertel Miglioranza Contents Principles 111 Indications 112 Pulmonary interstitial syndrome 112 Acute respiratory distress syndrome 113 Pleural effusion 113 Pneumothorax 113 Lung consolidations 113 Conclusion 113 References 114 Principles Assessment of the lung has been traditionally considered off limits for ultrasound, since air is a well-known foe of the ultrasound beam. The only established chest application of sonography is the assessment of pleural effusion. In recent years, ultrasound examination of the pulmonary parenchyma has been proposed as a new technique to detect many pulmonary conditions beyond pleural effusion, from extravascular lung water (EVLW) and pulmonary fibrosis to lung consolidations and pneumothorax (PNX) . The lung ultrasound (LUS) semiotics is relatively easy. In an aerated lung, the only structure that can be depicted is the pleura, appearing on the screen as a hyperechoic horizontal line that moves synchronously with respiration. This rhythmic movement is called lung sliding and provides a visual estimation of the pulmonary excursions during ventilation. Hyperechoic horizontal lines arising at regular intervals from the pleural line, called A-lines, are also part of the sonographic pattern of the normal lung (see % Fig. 16.1 and z Video 16.1). When the air content decreases because the pulmonary interstitium is pathologically occupied, as in the case of interstitial pulmonary oedema, the acoustic mismatch between air and the surrounding tissues changes, and some hyperechoic vertical reverberation artefacts are generated. They are called B-lines (or ultrasound lung comets) and are the sonographic sign of the pulmonary interstitial syndrome (see % Fig. 16.2 and z Video 16.2). When the air content further decreases, the acoustic window on the lung becomes completely accessible, and the lung may be directly visualized as a solid parenchyma, like the liver or the spleen (see % Fig. 16.3 and z Video 16.3). This is the case of lung consolidations, as in pneumonia or pulmonary infarctions. LUS can be performed using a variety of sonographic transducer: higher frequencies are optimal for the evaluation of the pleura and subpleural space (i.e. PNX and small subpleural consolidations); lower frequencies should be preferred for the evaluation of pleural effusion and interstitial syndromes. Visualization of lung consolidations depends on their size, with larger consolidations better visualized by lower-frequency probes and vice versa. The convex probe is the most versatile transducer. However, the possibility of performing LUS rapidly with different types of transducers is one of the advantages of the technique; in the case of emergency, especially for B-line assessment, the sonographer should not give up on scanning a patient just because the ‘ideal’ probe is not available . The probe should be positioned on the chest in the intercostal spaces, avoiding the ribs. The patients can be scanned in any position. In the setting of chronic patients, the scanning technique should be comprehensive, including the anterior, lateral, and dorsal chest. In the case of emergency with critically ill patients, a clinically driven, focused examination is advised. LUS is very suitable for a point-of-care approach, and adding LUS information to integrated multi-organ ultrasonography that can include the heart, inferior vena cava and other vessels, abdomen, and brain can be extremely effective and time-saving.