Contrast Echocardiography Can Save Nondiagnostic Exams in Mechanically Ventilated Patients

Abstract

Patients in an intensive care unit (ICU) under mechanical ventilation (MV) are very difficult to image by transthoracic echocardiography, diminishing the beneficial information that could be obtained by this noninvasive approach. The objective of this study is to assess whether the addition of a contrast agent to fundamental imaging (FI) can improve or change the initial diagnosis in cardiac postoperative patients under mechanical ventilation by enhancing endocardial border delineation and Doppler flow signal. Thirty mechanically ventilated post-cardiac surgery patients (20 men, mean age 61 +/- 13 years) were evaluated with FI before and after intravenous injection of contrast. Left ventricular endocardial border delineation score index (EBDSI), estimated left ventricular ejection fraction (LVEF), and color and spectral Doppler were analyzed. The use of contrast resulted in a significant increase in the number of well-delineated segments, with a salvage rate of 77% of nondiagnostic studies. EBDSI was 1.62 +/- 0.61, before contrast, increasing to 2.05 +/- 0.53 after it (P < 0.001). There was a change in the LVEF estimation in 5 exams, and a new wall motion abnormality was detected in other 4 exams, after the use of contrast. Moreover, a significant change was observed in the quantification of mitral regurgitation in 5 patients, in the aortic transvalvular peak gradient in 1 patient, and measurement of tricuspid regurgitation peak flow velocity in 8 patients. It is concluded that in cardiac postoperative patients under mechanical ventilation, intravenous injection of a contrast agent using FI resulted in a high salvage rate of studies and changed the initial diagnosis in a significant number of patients.

Impact of Contrast Echocardiography on Evaluation of Ventricular Function and Clinical Management in a Large Prospective Cohort

“…One study showed an increase in the level of confidence of LVEF assessment from 56% to 91% after CE (10). Costa et al (11) showed a salvage rate of 77% of nondiagnostic studies. Furthermore, 16.7% of patients had a change of more than 10% in LVEF after contrast enhancement.…”

“…Several studies have shown that CE improves the assessment of global and regional left ventricular (LV) function, enhances the detection of LV thrombi, and decreases variability of interpretation (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). It has been estimated that 10% to 15% of routine echocardiograms have incomplete endocardial resolution, reaching 25% to 30% in critically ill patients in the intensive care unit (ICU) (14).…”

Contrast echocardiography in daily clinical practice

“…Both American and European guidelines advocate the use of UCAs to improve endocardial border delineation when two or more segments of the left ventricle cannot be well defined [5, 6]. The salvage of such nondiagnostic studies using left ventricular opacification (LVO) has been reported to be as high as approximately 50% with higher rates of salvage in the intensive care unit [7–9]. It is only with the advent of contrast echocardiography that the percentage of nondiagnostic echocardiography studies has dropped to less than 5% [4].…”

Feasibility of Perflutren Microsphere Contrast Transthoracic Echocardiography in the Visualization of Ventricular Endocardium during Venovenous Extracorporeal Membrane Oxygenation in a Validated Ovine Model

“…Reasons for this include the recumbency of the patient, positive pressure ventilation, suboptimal lighting conditions, inability to position the patient to optimize the imaging, and sternotomies/drains preventing acquisition of conventional echocardiographic views. The addition of contrast‐specific echocardiographic imaging can help overcome these limitations and improve ventricular structural and functional assessment in the critical care complex …”