Análise comparativa do fractional flow reserve (FFR) e do instantaneous wave‐free ratio (iFR): resultados de um registo de 5 anos

Abstract

Resumo: Introdução e objetivos: A avaliação de lesões coronárias pelo instantaneous wave free ratio (iFR) tem gerado debate. Pretendeu‐se analisar o desempenho diagnóstico do iFR e o seu impacto na decisão de usar o fractional flow reserve (FFR) e nas características do procedimento. Métodos: Registo unicêntrico de doentes submetidos a avaliação funcional de lesões coronárias. O desempenho do iFR foi aferido com o FFR como referência. Valores de iFR 0,93 foram considerados positivos e negativos, respetivamente. Resultados: Avaliaram‐se 402 lesões, em 154 casos com ambas as técnicas, em 222 apenas com FFR e 26 apenas com iFR. Com um limiar de FFR ≤ 0,80, a área sob a curva foi de 0,73 (95% IC 0,65‐0,81) – valor ótimo de iFR ≤ 0,91. Efetuou‐se FFR em 93 de 94 lesões inconclusivas por iFR e em 69,1% dos restantes casos aferidos com iFR. O iFR e o FFR foram concordantes em 87% dos casos (X2 =22,43; p 0.93 was considered negative. Results: Functional testing was undertaken of 402 lesions, of which 154 were assessed with both techniques, 222 with FFR only, and 26 with iFR only. Using a cut‐off of ≤0.80 for iFR, the area under the curve was 0.73 (95% CI 0.65‐0.81), with an optimal value of ≤0.91. FFR was undertaken in 93 out of 94 lesions with an inconclusive iFR and was performed in 69.1% of the remaining iFR‐tested lesions. Concordance between iFR and FFR was 87% (chi‐square=22.43; p<0.001). Notwithstanding, there were four out of 13 cases (30.7%) of positive iFR with negative FFR and three out of 42 (7.1%) cases of negative iFR and positive FFR. This difference was significant (p=0.026). iFR had no impact on procedure time, fluoroscopy time or radiation dose. Conclusion: iFR had a reasonable diagnostic performance. Operators often chose to perform FFR despite conclusive iFR results. iFR and FFR were highly concordant, but a non‐negligible proportion of lesions classified as ischemic by iFR were classified as non‐ischemic by FFR. iFR had no impact on procedural characteristics. Palavras‐chave: Instantaneous wave‐free ratio, Fractional flow reserve, Avaliação funcional invasiva de lesões coronárias, Keywords: Instantaneous wave‐free ratio, Fractional flow reserve, Invasive functional assessment of coronary lesions