Abstract: Poster Presentations |

Application of Energy Loss Coefficient in Clinical Practice: The Role of Pressure Recovery in Aortic Stenosis FREE TO VIEW

Sirin Apiyasawat, MD*; Jayashri Aragam, MD
Author and Funding Information

Worcester Medical Center, University of Massachusetts, Worcester, MA


Chest. 2004;126(4_MeetingAbstracts):793S. doi:10.1378/chest.126.4_MeetingAbstracts.793S
Text Size: A A A
Published online


PURPOSE:  Discrepancies between measurements of aortic valve area by Doppler echocardiography and those by cardiac catheterization are largely due to the pressure recovery phenomenon. Recently, a study showed that calculating of energy loss coefficient (ELCO) from echocardiogram might resolve the discrepancies. This study is to evaluate the use of ELCO in clinical practice.

METHODS:  We retrospectively reviewed 71 patients (age 75.03 ±8.67, 54.9% male) who had cardiac catheterization and echocardiogram done less than 3 months apart for significant native aortic stenosis (AS). Aortic valve area by Doppler echocardiography (AVADop) and cardiac catheterization (AVAcath) were calculated using the standard continuity equation and Gorlin’s formula respectively. In order to account for pressure recovery phenomenon, AVADop was modified (ELCO) by using the following formula: ELCO = (AVADop x Aa) / (Aa - AVADop) = AVAcath, when Aa = cross-sectional area of the aorta at the level of sinotubular junction. The correlations between AVADop, ELCO, and AVAcath were analyzed.

RESULTS:  There was a fair correlation between AVADop and AVAcath (0.81±0.23 vs. 0.90±0.36 cm2, R=0.631, P=0.000000003). After substituting AVADop with ELCO, the correlation was improved (0.92±0.33 vs. 0.90±0.36 cm2, R=0.642, P=0.000000001). When AVADop was replaced by ELCO, 11 patients moved from the group of severe AS to moderate AS, and 4 patients moved from the group of moderate AS to mild AS. However, this correlation did not hold true in patients who had more than mild associated aortic insufficiency (AI). In patients with AI of at least mild to moderate degree (N=11), ELCO was poorly correlated with AVAcath (0.86±0.28 vs. 0.69±0.19 cm2, R= 0.265, P=0.43).

CONCLUSION:  AVADop generally overestimates AVAcath which could be corrected by calculating ELCO from AVADop. However, this calculation only confines to patients without significant degree of AI.

CLINICAL IMPLICATIONS:  ELCO, instead of AVADop, correlates better with AVAcath and is probably a better representation of a true aortic valve area.

Correlation of large effusion with pulsus parodoxus, electrical alternans and low voltages in EKG

Vol>500mlVol<500mlPulsus parodoxus present50Sensitivity[SEN]-23%,Specificity [SPE]-100%, Positive predictive value[PPV]-100%,Negative predictive value[NPV]-29%. Average amount of fluid if pulsus parodoxus present was 800 mlPulsus parodoxus absent177Electrical alternans present90SEN-41%,SPEC-100%,PPV-100%,NPV-35%. Average amount of fluid if electrical alternans present was 833mlElectrical alternans absent137Low voltages present50SEN-23%,SPE-100%,PPV-100%,NPV-29%. Average amount of fluid if low voltages present was 830 mlLow voltages absent177

Correlation of pulsus parodoxus and volume of pericardial effusion with echocardiographic evidence of tamponade

Tamponade presentTamponade absentPulsus parodoxus present50SEN-26%, SPE-100%,PPV- 100%,NPV-34%Pulsus parodoxus absent1410Vol>500ml156SEN-75%, SPEC-33%, PPV-71%, NPV-37%Vol<500ml53

DISCLOSURE:  S. Apiyasawat, None.

Wednesday, October 27, 2004

12:30 PM - 2:00 PM




Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

CHEST Journal Articles
PubMed Articles
  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543