The heart in the critically ill patient- an echocardiographic study
Abstract: The thesis describes aspects of left ventricular systolic and diastolic function examined with echocardiography in patients with systemic inflammation and shock. Background: Myocardial depression is a well-known complication in critically ill patients with shock. Echocardiography is increasingly used for assessing left ventricular (LV) function in these patients. Aims: 1) To describe the feasibility and reliability of LV systolic function parameters, and the association between different types of measurements 2) To investigate the time course of LV systolic and diastolic function parameters 3) To examine the relation of LV longitudinal function to other LV function parameters and biomarkers 4) To determine whether LV function parameters and cardiac biomarkers are associated with mortality. Methods: Transthoracic echocardiographic, hemodynamic parameters as well as laboratory measurements were assessed daily for a total of 7 days. Measurements from day 1 were assessed for their relation to short (28-day) and long term (1-year) mortality. Results: LV systolic function parameters were easily obtainable (93% to 100%) and had acceptable repeatability (coefficient of variation 3.1% to 10.6%). Eyeball ejection fraction and atrioventricular plane displacement¹ provided the most reliable results. The different parameters variably correlated to each other, and showed substantial variation over time (r= 0.101 to 0.949). LV systolic function parameters improved over time whereas most LV diastolic function parameters did not. The LV longitudinal parameter mitral annular plane excursion (MAPSE)¹ correlated significantly with markers of both LV systolic and diastolic function and with the cardiac biomarker high-sensitive troponin T. MAPSE was significantly associated with 28-day mortality but not long term mortality. High-sensitive TNT was an independent marker of 1-year mortality and was a univariate predictor of 28-day mortality. Some echocardiographic measurements of LV filling pressure were significantly associated with 1-year mortality. Conclusion: Transthoracic echocardiography is variably feasible in hemodynamically unstable, ventilated patients with different methods of measuring LV systolic function. Eyeball EF is reliable and can be used instead of more formal methods of EF quantification. The addition of parameters assessing LV longitudinal function, for example, MAPSE, is an advantage. MAPSE seemed even to reflect LV diastolic function and myocardial injury. Serial evaluations over the seven-day observation period revealed that most markers of LV diastolic function remained unchanged despite improvement of LV systolic function, markers of critical illness and systemic hemodynamic parameters. Echocardiographic measurements of LV filling pressure should be assessed as they may be related to long term mortality. The association of the cardiac biomarker high-sensitive Troponin with long term mortality was strong. ¹The terms atrioventricualar plane displacement (AVPD) and mitral annular plane systolic excursion (MAPSE) are used interchangeably.
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