Graft patency and progression of coronary artery disease after CABG assessed by angiography-derived fractional flow reserve

Impact of quantitative flow ratio on graft function in patients undergoing coronary artery bypass grafting

Recent studies showed that preoperative functional assessment with fractional flow reserve (FFR) could predict a long-term patency of arterial bypass grafts in patients with coronary artery bypass grafting (CABG). Quantitative flow ratio (QFR) is a novel angiography-based approach to estimate FFR. This study aimed to investigate whether preoperative QFR could discriminate arterial bypass function at 1 year after surgery. The PRIDE-METAL registry was a prospective, multicenter observational study that enrolled 54 patients with multivessel coronary artery disease. By protocol, left coronary stenoses were revascularized by CABG with arterial grafts, whereas right coronary stenoses were treated with coronary stenting. Follow-up angiography at 1 year after surgery was scheduled to assess arterial graft patency. QFR was performed using index angiography by certified analysts, blinded to bypass graft function. The primary end point of this sub-study was the discriminative ability of QFR for arterial graft function, as assessed by receiver-operating characteristic curve. Among 54 patients enrolled in the PRIDE-METAL registry, index and follow-up angiography was available in 41 patients with 97 anastomoses. QFR were analyzed in 35 patients (71 anastomoses) with an analyzability of 85.5% (71/83). Five bypass grafts were found to be non-functional at 1 year. The diagnostic performance of QFR was substantial (area under the curve: 0.89; 95% confidence interval: 0.83 to 0.96) with an optimal cutoff of 0.76 to predict functionality of bypass grafts. Preoperative QFR is highly discriminative for predicting postoperative arterial graft function.Trial registration: Clinical.gov reference: NCT02894255.

Preoperative angiography-derived fractional flow reserve may predict coronary artery bypass grafting occlusion and disease progression

BACKGROUND

Graft occlusion after coronary artery bypass grafting (CABG) has been associated with competitive flow of native coronary arteries.

OBJECTIVES

To assess with coronary computed tomography angiography (CCTA) graft occlusion and coronary artery disease (CAD) progression of native vessels after CABG and their relationship with angiography-derived vessel fractional flow reserve (vFFR) performed before surgery.

METHODS

Between 2006 and 2018, serial vFFR analyses were obtained before CABG in each major native coronary vessel from two institutions. All patients underwent follow-up CCTA.

RESULTS

In 171 consecutive patients, serial preoperative angiograms were suitable for vFFR analysis of 298 grafted and 59 nongrafted vessels. Median time between CABG and CCTA was 2.1 years. Preoperative vFFR was assessed in 131 left anterior descending artery (LAD), 132 left circumflex artery (LCX) and 94 right coronary aretry (RCA) and was less than 0.80 in 255 of 298 bypassed vessels. Graft occlusion was observed at CCTA in 28 of 298 grafts. The median preoperative vFFR value of native coronaries was higher in occluded compared with patent grafts (0.75 vs. 0.60, P < 0.001) and was associated with graft. The best vFFR cut-off to predict graft occlusion was 0.67. Progression of CAD was higher in grafted than in nongrafted vessels (89.6 vs. 47.5%, P < 0.001). Pre-CABG vFFR predicted disease progression of grafted native vessels (AUC = 0.83).

CONCLUSION

Preoperative vFFR derived from invasive coronary angiography was able to predict graft occlusion and CAD progression of grafted coronary arteries.

Pre-procedural planning of coronary revascularization by cardiac computed tomography: An expert consensus document of the Society of Cardiovascular Computed Tomography

Coronary CT angiography (CCTA) demonstrated high diagnostic accuracy for detecting coronary artery disease (CAD) and a key role in the management of patients with low-to-intermediate pretest likelihood of CAD. However, the clinical information provided by this noninvasive method is still regarded insufficient in patients with diffuse and complex CAD and for planning percutaneous coronary intervention (PCI) and surgical revascularization procedures. On the other hand, technology advancements have recently shown to improve CCTA diagnostic accuracy in patients with diffuse and calcific stenoses. Moreover, stress CT myocardial perfusion imaging (CT-MPI) and fractional flow reserve derived from CCTA (CT-FFR) have been introduced in clinical practice as new tools for evaluating the functional relevance of coronary stenoses, with the possibility to overcome the main CCTA drawback, i.e. anatomical assessment only. The potential value of CCTA to plan and guide interventional procedures lies in the wide range of information it can provide: a) detailed evaluation of plaque extension, volume and composition; b) prediction of procedural success of CTO PCI using scores derived from CCTA; c) identification of coronary lesions requiring additional techniques (e.g., atherectomy and lithotripsy) to improve stent implantation success by assessing calcium score and calcific plaque distribution; d) assessment of CCTA-derived Syntax Score and Syntax Score II, which allows to select the mode of revascularization (PCI or CABG) in patients with complex and multivessel CAD. The aim of this Consensus Document is to review and discuss the available data supporting the role of CCTA, CT-FFR and stress CT-MPI in the preprocedural and possibly intraprocedural planning and guidance of myocardial revascularization interventions.

Pre-procedural planning of coronary revascularization by cardiac computed tomography: An expert consensus document of the Society of Cardiovascular Computed Tomography

Coronary CT angiography (CCTA) demonstrated high diagnostic accuracy for detecting coronary artery disease (CAD) and a key role in the management of patients with low-to-intermediate pretest likelihood of CAD. However, the clinical information provided by this noninvasive method is still regarded insufficient in patients with diffuse and complex CAD and for planning percutaneous coronary intervention (PCI) and surgical revascularization procedures. On the other hand, technology advancements have recently shown to improve CCTA diagnostic accuracy in patients with diffuse and calcific stenoses. Moreover, stress CT myocardial perfusion imaging (CT-MPI) and fractional flow reserve derived from CCTA (CT-FFR) have been introduced in clinical practice as new tools for evaluating the functional relevance of coronary stenoses, with the possibility to overcome the main CCTA drawback, i.e. anatomical assessment only. The potential value of CCTA to plan and guide interventional procedures lies in the wide range of information it can provide: a) detailed evaluation of plaque extension, volume and composition; b) prediction of procedural success of CTO PCI using scores derived from CCTA; c) identification of coronary lesions requiring additional techniques (e.g., atherectomy and lithotripsy) to improve stent implantation success by assessing calcium score and calcific plaque distribution; d) assessment of CCTA-derived Syntax Score and Syntax Score II, which allows to select the mode of revascularization (PCI or CABG) in patients with complex and multivessel CAD. The aim of this Consensus Document is to review and discuss the available data supporting the role of CCTA, CT-FFR and stress CT-MPI in the preprocedural and possibly intraprocedural planning and guidance of myocardial revascularization interventions.

Quantitative flow ratio to predict long-term coronary artery bypass graft patency in patients with left main coronary artery disease

Purpose

Fractional flow reserve (FFR) has been demonstrated in some studies to predict long-term coronary artery bypass graft (CABG) patency. Quantitative flow ratio (QFR) is an emerging technology which may predict FFR. In this study, we hypothesised that QFR would predict long-term CABG patency and that QFR would offer superior diagnostic performance to quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS).

Methods

A prospective study was performed on patients with left main coronary artery disease who were undergoing CABG. QFR, QCA and IVUS assessment was performed. Follow-up computed tomography coronary angiography and invasive coronary angiography was undertaken to assess graft patency.

Results

A total of 22 patients, comprising of 65 vessels were included in the analysis. At a median follow-up of 3.6 years post CABG (interquartile range, 2.3 to 4.8 years), 12 grafts (18.4%) were occluded. QFR was not statistically significantly higher in occluded grafts (0.81 ± 0.19 vs. 0.69 ± 0.21; P = 0.08). QFR demonstrated a discriminatory power to predict graft occlusion (area under the receiver operating characteristic curve, 0.70; 95% confidence interval [CI], 0.52 to 0.88; P = 0.03). At long-term follow-up, the risk of graft occlusion was higher in vessels with a QFR > 0.80 (58.6% vs. 17.0%; hazard ratio, 3.89; 95% CI, 1.05 to 14.42; P = 0.03 by log-rank test). QCA (minimum lumen diameter, lesion length, diameter stenosis) and IVUS (minimum lumen area, minimum lumen diameter, diameter stenosis) parameters were not predictive of long-term graft patency.

Conclusions

QFR may predict long-term graft patency in patients undergoing CABG.

Angiography-based estimation of coronary physiology: A frame is worth a thousand words

Cumulative evidence has shown that coronary revascularization should be guided by functional significance of coronary lesions. Fractional flow reserve (FFR) is the gold standard for assessment of hemodynamic significance of coronary stenosis and FFR-guided percutaneous coronary intervention has improved clinical outcomes in patients with coronary artery disease. However, limitations of FFR such as increased operational time and cost, requirement of pressure wire and adenosine and technical difficulties have led to significant underutilization of the method in clinical practice. In the last few years, several methods of FFR estimation based on coronary angiography images have emerged to overcome invasive FFR limitations. The common elements of the novel indices include a 3D anatomical reconstruction of coronary vessels by angiographic projections and various approaches to fluid dynamics computation. Angiography-derived FFR methods have shown high diagnostic accuracy compared to invasive FFR. Although there are promising results regarding their prognostic role, large randomized trials evaluating clinical outcomes are lacking. The aim of this review is to present currently available angiography-derived FFR indices and highlight their differences, advantages, disadvantages and potential clinical implications.

Influence of fractional flow reserve on grafts patency: Systematic review and patient-level meta-analysis

OBJECTIVE

To investigate the impact of invasive functional guidance for coronary artery bypass graft surgery (CABG) on graft failure.

BACKGROUND

Data on the impact of fractional flow reserve (FFR) in guiding CABG are still limited.

METHODS

Systematic review and individual patient data meta-analysis were performed. Primary objective was the risk of graft failure, stratified by FFR. Risk estimates are reported as odds ratios (ORs) derived from the aggregated data using random-effects models. Individual patient data were analyzed using mixed effect model to assess relationship between FFR and graft failure. This meta-analysis is registered in PROSPERO (CRD42020180444).

RESULTS

Four prospective studies comprising 503 patients referred for CABG, with 1471 coronaries, assessed by FFR were included. Graft status was available for 1039 conduits at median of 12.0 [IQR 6.6; 12.0] months. Risk of graft failure was higher in vessels with preserved FFR (OR 5.74, 95% CI 1.71-19.29). Every 0.10 FFR units decrease in the coronaries was associated with 56% risk reduction of graft failure (OR 0.44, 95% CI 0.34 to 0.59). FFR cut-off to predict graft failure was 0.79.

CONCLUSION

Surgical grafting of coronaries with functionally nonsignificant stenoses was associated with higher risk of graft failure.