Diagnostic accuracy and cost-effectiveness of contrast echocardiography on evaluation of cardiac function in technically very difficult patients in the intensive care unit
Heart Failure, Systolic
Echocardiographic assessment of cardiac function can be quite difficult in the intensive care unit and may require transesophageal echocardiography (TEE). We therefore compared harmonic imaging alone or in combination with contrast to TEE in 32 consecutive patients in the intensive care units who were considered technically very difficult (> or =50% of the 16 segments not visualized from any view). Excellent or adequate endocardial visualization was achieved in 13% of segments with fundamental imaging, 34% with harmonic imaging, and 87% with contrast (p < 0.0001); the latter success rate was similar to TEE (87% vs 90%; p = NS). When TEE was used as the standard, agreement in exact interpretation of wall motion increased from 48% for fundamental imaging to 58% with harmonic imaging, and reached 70% with contrast (p <0.0001). Contrast had the best sensitivity (89%) for detecting wall motion abnormalities. Estimation of ejection fraction was possible in 31% with fundamental imaging, 50% with harmonic imaging, and in 97% with contrast. Ejection fraction quantitated by contrast enhancement correlated best with TEE (r = 0.91). Cost-effectiveness analysis revealed that contrast echo was cost-effective compared with TEE in determining regional and global ventricular function, with a cost saving of 3% and 17%, respectively. Thus, contrast echocardiography provides an accurate, safe, and cost-effective alternative to TEE for evaluating ventricular function in technically very difficult studies.