Impact of Age on the Functional Evaluation of Intermediate Coronary Stenoses With Instantaneous Wave-Free Ratio and Fractional Flow Reserve

Coronary Physiology: Modern Concepts for the Guidance of Percutaneous Coronary Interventions and Medical Therapy

Recent evidence on ischemia, rather than coronary artery disease (CAD), representing a major determinant of outcomes, has led to a progressive shift in the management of patients with ischemic heart disease. According to most recent guidelines, myocardial revascularization strategies based on anatomical findings should be progressively abandoned in favor of functional criteria for the guidance of PCI. Thus, emerging importance has been assigned to the assessment of coronary physiology in order to determine the ischemic significance of coronary stenoses. However, despite several indexes and tools that have been developed so far, the existence of technical and clinical conditions potentially biasing the functional evaluation of the coronary tree still cause debates regarding the strategy of choice. The present review provides an overview of the available methods and the most recent acquirements for the invasive assessment of ischemia, focusing on the most widely available indexes, fractional flow reserve (FFR) and instant-wave free ratio (iFR), in addition to emerging examples, as new approaches to coronary flow reserve (CFR) and microvascular resistance, aiming at promoting the knowledge and application of those "full physiology" principles, which are generally advocated to allow a tailored treatment and the achievement of the largest prognostic benefits.

Long-Term Outcomes With Drug-Eluting Balloon for the Treatment of In-Stent Restenosis and De Novo Lesions: The Novara-Biella-Trento (NOBITRE) Registry

Drug-coated balloons (DCBs) have emerged for percutaneous coronary interventions (PCI) of in-stent restenosis or particular anatomical subsets. We provide a real-world analysis of the prognostic determinants and long-term outcomes of patients treated with DCB for any lesion in a comprehensive multicenter registry. The primary study endpoint was the occurrence of major cardiovascular events (MACE: composite of all-cause death, myocardial infarction, and target vessel revascularization) at the longest available follow-up. We included 267 patients (196 treated for in-stent restenosis and 71 for de novo lesions), with a median follow-up of 616 [368–1025] days. MACE occurred in 70 (26.2%) of the patients and related with higher rates of in-stent restenosis (P = .04), longer and more type C lesions ( P = .05 and P = .04). At multivariate Cox-regression, type C lesions emerged as the only independent predictor of MACE (adjusted OR [95% CI] = 1.83[1.13–2.97], P = .014), mainly driven by target vessel revascularization (adjusted OR[95% CI] = 1.78[1.05–2.95], P = .03) not conditioning survival. In-stent restenosis emerged as major determinant of TLF (adjusted OR[95% CI] = 2.59[1.17–5.75], P = .02). DCBs represent a treatment option for any lesion; however, type C and restenotic lesions are associated with an increased risk of MACE and target lesion failure, where the optimal strategies for patients’ selection and lesion preparation are still undefined.

Fractional Flow Reserve: Patient Selection and Perspectives

The aim of this review was to discuss the current practice and patient selection for invasive FFR, new techniques to estimate invasive FFR and future of coronary physiology tests. We elaborate on the indication and application of FFR and on the contraindications and concerns in certain patient populations.

Impact of sex on the functional assessment of intermediate coronary lesions by instantaneous wave-free ratio

Sex differences in coronary physiology and in the pathogenesis of coronary artery disease (CAD) have been previously described. Contrasting data have been reported, so far, about the impact of sex on the assessment of the functional significance of intermediate coronary stenoses by fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR). The present study aimed at assessing the sex differences in the results of iFR in a cohort of patients undergoing coronary angiography.

METHODS

We included patients undergoing coronary angiography and the functional assessment of intermediate (40 to 70%) coronary lesions in 2 centers. iFR measurement was performed by pressure-recording guidewire and automatically calculated at the core laboratory using the manufacturers' dedicated software. Quantitative parameters of the coronary lesions were calculated by an automatic edge-detection system. Minimal luminal diameter (MLD), reference diameter (RD), percent diameter stenosis, and length of the lesion were measured. Positive iFR was considered for values < 0.90.

RESULTS

We included 325 patients undergoing coronary angiography and iFR evaluation of 371 intermediate coronary stenoses, including 20.6% of women. Females were older, displayed lower body weight and hemoglobin, lower rate of active smoking (p < 0.001) and previous PCI (p = 0.04), lower platelet count (p = 0.001) and creatinine (p = 0.02). Systolic blood pressure and heart rate at admission were more elevated in women (p = 0.001 and p = 0.05, respectively). At angiography, multivessel coronary artery disease was more uncommon (p = 0.001) and proximal lesions were more frequently assessed by iFR (p = 0.04). Mean values of iFR did not differ with sex and neither the percentage of positive iFR (19.1% vs 18.8%, p = 0.99, adjusted OR[95%CI] = 0.51[0.18-1.48], p = 0.22).

CONCLUSION

Among patients undergoing functional assessment of intermediate coronary lesions by instantaneous wave-free ratio, no impact of sex was observed on the absolute values or the rate of positivity of iFR.

Preprocedural β-Blockers in the Functional Assessment of Intermediate Coronary Lesions by Instantaneous Wave-Free Ratio

AIM

Instantaneous wave-free ratio (iFR) has emerged as the strategy of choice for the assessment of intermediate coronary lesions. The impact of preprocedural β-blockers therapy on the iFR was the aim of this study.

METHODS

We included patients undergoing functional assessment of intermediate (40%-70%) coronary lesions in 2 centers. The iFR measurement was performed by pressure-recording guidewire and calculated at the core laboratory using the manufacturers' dedicated software. Minimal luminal diameter, reference diameter, percent diameter stenosis, and length of the lesion were measured. Positive iFR was considered for values <0.90.

RESULTS

We included 197 patients undergoing functional evaluation of 223 coronary lesions. Patients on β-blockers (69%) had more frequently hypertension (P = .05); previous myocardial infarction (P = .01); therapy with clopidogrel (P = .02), statins, and aspirin; and acute coronary syndrome at presentation (P < .001, respectively). Mean iFR values were slightly higher in patients on β-blockers (0.94 ± 0.06 vs 0.92 ± 0.06, P = .11). The rate of positive iFR was significantly lower with β-blockers (14.9% vs 27.5%, P = .04). On multivariate analysis, β-blockers use was a predictor of the significance of coronary stenoses (odds ratio [OR] = 0.48; 95% CI = 0.23-0.98; P = .05) together with lesion length (OR = 1.04; 95% CI = 1.01-1.07; P = .007).

CONCLUSION

Among patients undergoing iFR, preprocedural β-blockers are associated with higher absolute values and a lower rate of positive iFR.