Impact of pannus formation on hemodynamic dysfunction of prosthetic aortic valve: pannus extent and its relationship to prosthetic valve motion and degree of stenosis
Although pannus is an important cause of prosthetic valve dysfunction, the minimum pannus size that can induce hemodynamic dysfunction has not yet been determined. This study investigated the correlation between the limitation of motion (LOM) of the prosthetic valve and pannus extent and determined the pannus extent that could induce severe aortic stenosis.
This study included 49 patients who underwent mechanical aortic valve replacement (AVR) and showed pannus on cardiac computed tomography (CT). Pannus width, ratio of pannus width to valve diameter, pannus area, effective orifice area, encroachment ratio by pannus, pannus involvement angle and percent LOM of mechanical valves were evaluated on CT. Transvalvular peak velocity (TPV) and transvalvular pressure gradient (TPG) were measured by transesophageal echocardiography to determine the degree of aortic stenosis. The relationship between percent LOM of the prosthetic valve and pannus extent and the cut-off of pannus extent required to induce severe aortic stenosis were evaluated.
The mean interval between AVR and pannus formation was 11 years and was longer in patients with than without severe aortic stenosis (14.0 vs. 7.3 years). On CT, the percent LOM of the prosthetic valve was significantly associated with the extent of pannus only in patients with pannus involvement angle > 180° (r = 0.55–0.68, P < 0.01). Pannus width, effective orifice area, and encroachment ratio were significantly associated with increased TPV and TPG (r = 0.51–0.62, P < 0.01). Pannus width > 3.5 mm, pannus width/valve inner diameter > 0.15, and encroachment ratio > 0.14 were significantly associated with severe aortic stenosis (TPV > 4 m/s; mean TPG ≥ 35 mmHg), with c-indices of 0.74–079 (P < 0.005).
CT-derived pannus extent parameters are good indicators of significant hemodynamic changes with increased TPV and mean TPG.
KeywordsPannus Aortic valve replacement Mechanical valve Computed tomography
This work was supported by National Research Foundation of Korea (NRF) Grants funded by the Korean government (MSIP) (NRF-2016R1A1A1A05921207 and NRF-2015R1A2A2A04003034) and by a grant (2017–7208) from the Asan Institute for Life Sciences, Asan Medical Center, Seoul, Korea. This work was also funded by the Industrial Strategic Technology Development Program (10072064) of the Ministry of Trade Industry and Energy of Korea.
All authors take responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation.
Compliance with ethical standards
Conflict of interest
Authors declare that they have no conflict of interest.
- 8.Otto CM (2013) Textbook of clinical echocardiography. Elsevier, AmsterdamGoogle Scholar
- 22.Zoghbi WA, Chambers JB, Dumesnil JG et al (2009) Recommendations for evaluation of prosthetic valves with echocardiography and doppler ultrasound: a report From the American Society of Echocardiography’s Guidelines and Standards Committee and the Task Force on prosthetic valves, developed in conjunction with the American College of Cardiology Cardiovascular Imaging Committee, Cardiac Imaging Committee of the American Heart Association, the European Association of Echocardiography, a registered branch of the European Society of Cardiology, the Japanese Society of Echocardiography and the Canadian Society of Echocardiography, endorsed by the American College of Cardiology Foundation, American Heart Association, European Association of Echocardiography, a registered branch of the European Society of Cardiology, the Japanese Society of Echocardiography, and Canadian Society of Echocardiography. J Am Soc Echocardiogr 22:975–1014CrossRefPubMedGoogle Scholar
- 23.Nagueh SF, Smiseth OA, Appleton CP et al (2016) Recommendations for the evaluation of left ventricular diastolic function by echocardiography: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr 29:277–314CrossRefPubMedGoogle Scholar
- 32.Barbetseas J, Nagueh SF, Pitsavos C, Toutouzas PK, Quiñones MA, Zoghbi WA (1998) Differentiating thrombus from pannus formation in obstructed mechanical prosthetic valves: an evaluation of clinical, transthoracic and transesophageal echocardiographic parameters. J Am Coll Cardiol 32:1410–1417CrossRefPubMedGoogle Scholar