Cardiogenic shock echocardiography or ultrasound
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]
Overview
Attending to the catastrophic outcome of cardiogenic shock in a very short time span, its diagnosis must be reached as early as possible in order for proper therapy to be started. This period until diagnosis and treatment initiation is particularly important in the case of cardiogenic shock since the mortality rate of this condition complicating acute-MI is very high, along with the fact that the ability to revert the damage caused, through reperfusion techniques, declines considerably with diagnostic delays. Therefore and due to the unstable state of these patients, the diagnostic evaluations are usually performed as supportive measures are initiated. The diagnostic measures should start with the proper history and physical examination, including blood pressure measurement, followed by an EKG, echocardiography, chest x-ray and collection of blood samples for evaluation. The physician should keep in mind the common features of shock, irrespective of the type of shock, in order to avoid delays in the diagnosis. Although not all shock patients present in the same way, these features include: abnormal mental status, cool extremities, clammy skin, manifestations of hypoperfusion, such as hypotension and oliguria, as well as evidence of metabolic acidosis on the blood results. Echocardiography is an important imaging modality for the evaluation of the patient with cardiogenic shock. This test will allow the identification of certain characteristics that, when complemented by a proper medical history and physical examination, will likely prompt to the diagnosis. These may include: poor wall motion, papillary muscle rupture, pseudoaneurysms, ventricular septal defects, among others. The echocardiographic findings may also suggest or rule out a different diagnosis. The test will provide information about the overall hemodynamic status of the heart as well, which may reveal to be vital in order to plan further measures and predict the outcome.[1]
Echocardiography
In recent years noninvasive means of estimating cardiac function have seen their usage increased considerably. These methods, such as echocardiography, have helped reducing the use of invasive means, like right heart catheterization, in acute coronary syndrome patients. Echocardiography with Doppler imaging has become common practice in recent years across many institutions, for bedside evaluation of cardiac status, including: PA systolic pressure, PCWP, overall function, valvular competence and eventual mechanical complications arising from ACS, such as papillary muscle rupture or ventricular septal rupture, helping in the confirmation of the diagnosis. The collection of hemodynamic parameters through echocardiography also contributes to a timely management of these patients, when compared to other more invasive methods. However, some possible drawbacks may arise in the interpretation of echocardiographic data, such as: overestimation of cardiac output in patients whose reason for cardiogenic shock is VSD, as well as overestimation of PCWP in those with right ventricular myocardial infarction causing a leftward shift of the interventricular septum. Therefore, despite the importance of diagnostic imaging methods in assessing hemodynamic data and laboratory values, possibly confirming a suspected diagnosis, these must always follow a careful assessment of the patient by a physician.[2][3]
Echocardiography may be performed by 2 different approaches, the transthoracic and the transesophageal approaches:
- Transthoracic - easily accessible, however, sometimes it does not provide an adequate image, particularly in critically ill patients on mechanical ventilatory support. It may underestimate certain conditions as well, such as a mitral regurgitation that may appear milder on this approach, later revealing more sever on the TEE.
- Tansesophageal - although not as accessible as the transthoracic approach, this allows for a better and more accurate visualization of the possible cause of cardiogenic shock, such as MR or VSR, particularly when complemented by color flow Doppler.
In a patient with cardiogenic shock complicating left or right ventricular dysfunction, echocardiography may provide valuable findings to support the diagnosis, including:[4][5][6]
- depressed left or right ventricle systolic function
- elevated filling pressures
- decreased stroke volume
- tamponade from increased pericardial fluid
- mitral regurgitation
- proximal aortic dissection
- ventricular septal rupture
In the case of right ventricle myocardial infarction, echocardiographic findings may include:[7][8][9]
- RV hypokinesis
- RV akinesis
- Right atrial enlargement
- Ventricular dilation
- Bowing of intraventricular septum into the LV
In acute mitral regurgitation, echocardiographic findings may include:
In ventricular septal rupture, echocardiographic findings may include:
In free wall rupture, echocardiographic findings may include:
Once the cause for the cardiogenic shock and instability of the patient have been resolved, echocardiography constitutes a good method to monitor the hemodynamic status of the heart during patient's recovery and follow-up.
References
- ↑ Longo, Dan L. (Dan Louis) (2012). Harrison's principles of internal medici. New York: McGraw-Hill. ISBN 978-0-07-174889-6.
- ↑ Hasdai, David. (2002). Cardiogenic shock : diagnosis and treatmen. Totowa, N.J.: Humana Press. ISBN 1-58829-025-5.
- ↑ Porter A, Iakobishvili Z, Haim M, Behar S, Boyko V, Battler A; et al. (2005). "Balloon-floating right heart catheter monitoring for acute coronary syndromes complicated by heart failure--discordance between guidelines and reality". Cardiology. 104 (4): 186–90. doi:10.1159/000088107. PMID 16155391.
- ↑ Hasdai, David. (2002). Cardiogenic shock : diagnosis and treatmen. Totowa, N.J.: Humana Press. ISBN 1-58829-025-5.
- ↑ Reynolds HR, Hochman JS (2008). "Cardiogenic shock: current concepts and improving outcomes". Circulation. 117 (5): 686–97. doi:10.1161/CIRCULATIONAHA.106.613596. PMID 18250279.
- ↑ Antman, E. M. (2004). "ACC/AHA Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction--Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1999 Guidelines for the Management of Patients With Acute Myocardial Infarction)". Circulation. 110 (5): 588–636. doi:10.1161/01.CIR.0000134791.68010.FA. ISSN 0009-7322.
- ↑ Ng, R.; Yeghiazarians, Y. (2011). "Post Myocardial Infarction Cardiogenic Shock: A Review of Current Therapies". Journal of Intensive Care Medicine. 28 (3): 151–165. doi:10.1177/0885066611411407. ISSN 0885-0666.
- ↑ Lopez-Sendon J, Garcia-Fernandez MA, Coma-Canella I, Yangüela MM, Bañuelos F (1983). "Segmental right ventricular function after acute myocardial infarction: two-dimensional echocardiographic study in 63 patients". Am J Cardiol. 51 (3): 390–6. PMID 6823853.
- ↑ Dell'Italia LJ, Starling MR, Crawford MH, Boros BL, Chaudhuri TK, O'Rourke RA (1984). "Right ventricular infarction: identification by hemodynamic measurements before and after volume loading and correlation with noninvasive techniques". J Am Coll Cardiol. 4 (5): 931–9. PMID 6092446.