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. 2022 Nov;119(5):705-713.
doi: 10.36660/abc.20220176.

Adjusting RFR by Predictors of Disagreement, "The Adjusted RFR": An Alternative Methodology to Improve the Diagnostic Capacity of Coronary Indices

[Article in English, Portuguese]
Diego Fernández-Rodríguez  1   2 , Juan Casanova-Sandoval  1   2 , Ignacio Barriuso  1   2 , Kristian Rivera  1   2 , Imanol Otaegui  3 , Bruno García Del Blanco  3 , Teresa Gil Jiménez  4 , Manuel López-Pérez  4 , Marcos Rodríguez-Esteban  5 , Francisco Torres-Saura  6 , Víctor Jiménez Díaz  7 , Raymundo Ocaranza-Sánchez  8 , Vicente Peral Disdier  9 , Guillermo Sánchez Elvira  10 , Fernando Worner  1   2
Affiliations

Adjusting RFR by Predictors of Disagreement, "The Adjusted RFR": An Alternative Methodology to Improve the Diagnostic Capacity of Coronary Indices

[Article in English, Portuguese]
Diego Fernández-Rodríguez et al. Arq Bras Cardiol. 2022 Nov.

Abstract
in English, Portuguese

Background: Cutoff thresholds for the "resting full-cycle ratio" (RFR) oscillate in different series, suggesting that population characteristics may influence them. Likewise, predictors of discordance between the RFR and fractional flow reserve (FFR) have been documented. The RECOPA Study showed that diagnostic capacity is reduced in the RFR "grey zone", requiring the performance of FFR to rule out or confirm ischemia.

Objectives: To determine predictors of discordance, integrate the information they provide in a clinical-physiological index, the "Adjusted RFR", and compare its agreement with the FFR.

Methods: Using data from the RECOPA Study, predictors of discordance with respect to FFR were determined in the RFR "grey zone" (0.86 to 0.92) to construct an index ("Adjusted RFR") that would weigh RFR together with predictors of discordance and evaluate its agreement with FFR.

Results: A total of 156 lesions were evaluated in 141 patients. Predictors of discordance were: chronic kidney disease, previous ischemic heart disease, lesions not involving the anterior descending artery, and acute coronary syndrome. Though limited, the "Adjusted RFR" improved the diagnostic capacity compared to the RFR in the "grey zone" (AUC-RFR = 0.651 versus AUC-"Adjusted RFR" = 0.749), also showing an improvement in all diagnostic indices when optimal cutoff thresholds were established (sensitivity: 59% to 68%; specificity: 62% to 75%; diagnostic accuracy: 60% to 71%; positive likelihood ratio: 1.51 to 2.34; negative likelihood ratio: 0.64 to 0.37).

Conclusions: Adjusting the RFR by integrating the information provided by predictors of discordance to obtain the "Adjusted RFR" improved the diagnostic capacity in our population. Further studies are required to evaluate whether clinical-physiological indices improve the diagnostic capacity of RFR or other coronary indices.

Fundamento: Os limiares de corte para a “relação do ciclo completo de repouso” (RFR) oscilam em diferentes séries, sugerindo que as características da população podem influenciá-los. Da mesma forma, foram documentados preditores de discordância entre a RFR e a reserva de fluxo fracionado (FFR). O Estudo RECOPA, mostrou que a capacidade diagnóstica está reduzida na “zona cinzenta” da RFR, tornando necessária a realização de FFR para descartar ou confirmar isquemia.

Objetivos: Determinar os preditores de discordância, integrar as informações que eles fornecem em um índice clínico-fisiológico: a “RFR Ajustada”, e comparar sua concordância com o FFR.

Métodos: Usando dados do Estudo RECOPA, os preditores de discordância em relação à FFR foram determinados na “zona cinzenta” da RFR (0,86 a 0,92) para construir um índice (“RFR Ajustada”) que pesaria a RFR juntamente com os preditores de discordância e avaliar sua concordância com a FFR.

Resultados: Foram avaliadas 156 lesões em 141 pacientes. Os preditores de discordância foram: doença renal crônica, cardiopatia isquêmica prévia, lesões não envolvendo a artéria descendente anterior esquerda e síndrome coronariana aguda. Embora limitada, a “RFR Ajustada” melhorou a capacidade diagnóstica em comparação com a RFR na “zona cinzenta” (AUC-RFR = 0,651 versus AUC-“RFR Ajustada” = 0,749), mostrando também uma melhora em todos os índices diagnósticos quando foram estabelecidos limiares de corte otimizados (sensibilidade: 59% a 68%; especificidade: 62% a 75%; acurácia diagnóstica: 60% a 71%; razão de verossimilhança positiva: 1,51 a 2,34; razão de verossimilhança negativa: 0,64 a 0,37).

Conclusões: Ajustar a RFR integrando as informações fornecidas pelos preditores de discordância para obter a “RFR Ajustada” melhorou a capacidade diagnóstica em nossa população. Mais estudos são necessários para avaliar se os índices clínico-fisiológicos melhoram a capacidade diagnóstica da RFR ou de outros índices coronarianos.

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Conflict of interest statement

Potencial Conflito de Interesse

Declaro não haver conflito de interesses pertinentes.

Figures

Figura 1
Figura 1. Curvas ROC de RFR versus FFR ≤ 0,80 e “RFR Ajustada” e FFR ≤ 0,80. AUC: área sob a curva; FFR: reserva de fluxo fracionado; ROC: característica de operação do receptor; RFR: relação do ciclo completo de repouso. A curva ROC mostrou uma AUC de 0,651 (0,559 a 0,744; p = 0,002) para a RFR, melhorando a AUC para a “RFR Ajustada” para 0,749 (0,669 a 0,828; p < 0,001) e estabelecendo um valor de 0,8172 como limite de corte otimizado para a “RFR Ajustada”.
Figura 2
Figura 2. Comparação dos parâmetros diagnósticos de acordo com as Tabelas 2 × 2 para os limiares de corte de RFR (≤ 0,89) e “RFR Ajustada” (≤ 0,8172) versus FFR (≤ 0,80). FFR: reserva de fluxo fracionado; FN: falso negativo; FP: falso positivo; LR+: razão de verossimilhança positiva; LR-: razão de verossimilhança negativa; RFR: relação do ciclo completo de repouso; VN: verdadeiro negativo; VP: verdadeiro positivo; VPN: valor preditivo negativo; VPP: valor preditivo positivo.
Figure 1
Figure 1. ROC curves of RFR versus FFR ≤ 0.80 and “Adjusted RFR” and FFR ≤ 0.80. AUC: area under the curve; FFR: fractional flow reserve; ROC: receiver operating characteristic; RFR: resting full-cycle ratio. The ROC curve showed an AUC for the RFR of 0.651 (0.559 to 0.744; p = 0.002), improving the AUC for “Adjusted RFR” to 0.749 (0.669 to 0.828; p < 0.001) and establishing as optimum cutoff threshold for “Adjusted RFR” a value of 0.8172.
Figure 2
Figure 2. Comparison of diagnostic parameters according to 2 × 2 Tables for the cutoff thresholds of RFR (≤ 0.89) and “Adjusted RFR” (≤ 0.8172) versus FFR (≤ 0.80). FFR: fractional flow reserve; FN: false negative; FP: false positive; NPV: negative predictive value; LR+: positive likelihood ratio; LR-: negative likelihood ratio; PPV: positive predictive value; RFR: resting full-cycle ratio; TN: true negative; TP: true positive.
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