F. Robert et al., SIGNIFICANCE OF STRANDS ON MITRAL MECHANICAL PROSTHESES DURING LATE FOLLOW-UP AFTER SURGERY, Echocardiography, 13(3), 1996, pp. 265-270
The presence of ''strands'' on mitral mechanical prostheses (MMP) has
been described, although their significance has yet to be established.
The aim of this study was to determine the incidence and clin ical im
plications of ''strands'' on MMP in Late follow-up by a retrospective
analysis of 320 consecutive patients who had undergone a transesophage
al echocardiographic (TEE) examination under standardized conditions 7
+/- 6 years after mitral surgery. Twenty patients (6.25%) with ''stra
nds,'' defined as highly mobile Linear echogenic densities, were ident
ified. This group was compared with a control group of 38 patients, ma
tched for age, sex, and interval between surgery and TEE study, select
ed at random from this population. Patients with MMP dysfunction, were
excluded. Type of prosthesis, echographic characteristics (left atria
l diameter, spontaneous echo contrast, ejection fraction), and anticoa
gulant status were not found to bear any relationship to the presence
of strands. However, the prevalence of previous embolic events was sig
nificantly higher in the ''strand'' group (10/20 [50%]) than in the co
ntrol group (7/38 [18.4%]) (P < 0.05). The ''strand'' group also conta
ined more patients with a prior history of mitral prosthesis thrombosi
s (7/20 [35%] vs 1/30 [2.6%]; P < 0.05). However, long-term follow-up
(1-4 years) was uneventful. These results suggest that: (1) in late fo
llow-up, strands are rare in patients with MMP (6%); and (2) strands w
ere related to previous thromboembolic episodes.