Is cerebral microembolism in mechanical prosthetic heart valves clinically relevant?

Zurab G. Nadareishvili, Vadim Beletsky, Sandra E. Black, Stephen E. Fremes, Morris Freedman, David Kurzman, Larry Leach, John W. Norris

Research output: Contribution to journalArticlepeer-review

Abstract

Background and Purpose. High-intensity transient signals (HITS) are frequently detected by transcranial Doppler (TCD) ultra-sound in patients with mechanical prosthetic heart valves (PHVs), but published data about their clinical relevance are controversial. This study was undertaken to determine the clinical relevance of HITS in patients with mechanical PHVs. Methods. The authors prospectively studied patients with mechanical PHVs using TCD monitoring for microemboli detection with and without O2 inhalation. The cognitive testing of patients included the Mini-Mental State Examination, the Dementia Rating Scale, and MicroCog. Results. The authors studied 36 patients (20 women, aged 58 ± 13 years). HITS were detected in 72% of patients, with a nonsignificant increase of HITS rate in the aortic valve group (P = .07). There was no significant difference in HITS rate between asymptomatic and symptomatic patients. In a multiple linear regression model, HITS rate was predicted only by younger age (P = .024). No correlation was found between HITS rate and the cognitive performance of patients. There was a significant decrease in HITS rate after 100% O2 inhalation compared to baseline levels (32.8 ± 40.2 vs 6.1 ± 11.3, P = .011). Subgroup analysis in asymptomatic patients confirmed this finding (P = .017), but in symptomatic patients, decreased HITS rate was not statistically significant (P = .18). Conclusion. Only age was a significant predictor of HITS in patients with mechanical PHVs. The lack of association between HITS, clinical symptoms, and cognitive functioning suggests that most of these signals represent harmless epiphenomena, and only HITS detected after O2 inhalation have any clinical relevance.

Original languageEnglish (US)
Pages (from-to)310-315
Number of pages6
JournalJournal of Neuroimaging
Volume12
Issue number4
DOIs
StatePublished - Oct 2002
Externally publishedYes

Keywords

  • Doppler
  • Embolism
  • Prosthetic heart valves
  • Transcranial
  • Ultrasonography

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Clinical Neurology

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