Rate Pressure Products Affect the Relationship between the Fractional Flow Reserve and Instantaneous Wave-Free Ratio

Diagnostic performances of Nonhyperemic Pressure Ratios and Coronary Angiography-Based Fractional Flow Reserve against conventional Wire-Based Fractional Flow Reserve

BACKGROUND

Nonhyperemic pressure ratios (NHPRs) have been proposed as alternatives to fractional flow reserve (FFR) without induction of hyperemia. More recently, imaging based-FFR estimation, especially coronary angiography-derived FFR (Angio-FFR) measurement, is proposed to estimate wire-based FFR. However, little is known about the diagnostic performance of these indices against conventional FFR.

AIMS

We aimed to assess and compare the diagnostic performance of both NHPRs and coronary Angio-FFR against wire-based conventional FFR.

METHODS

PubMed and Embase databases were systematically searched for peer-reviewed original articles up to 08/2022. The primary outcomes were the pooled sensitivity and specificity as well as the area under the curve (AUC) of the summary receiver-operating characteristic curve of those indices.

RESULTS

A total of 6693 records were identified after a literature search, including 37 reports for NHPRs and 34 for Angio-FFR. Overall, NHPRs have a lower diagnostic performance in estimating wire-based FFR with an AUC of 0.85 (0.81, 0.88) when compared with Angio-FFR of 0.95 (0.93, 0.97). When all four modalities of NHPRs (iFR, Pd/Pa, DPR, RFR) were compared, those had overlapping AUCs without major differences among each other. Similarly, when the two most commonly used Angio-FFR (QFR, FFR angio ) were compared, those had overlapping AUCs without major differences among each other.

CONCLUSION

Angio-FFR may offer a better estimation of wire-based FFR than NHPRs. Our results support a wider use of Angio-FFR in the cardiac catheterization laboratory to streamline our workflow for coronary physiologic assessment.

CLASSIFICATIONS

FFR,, stable ischemic disease and non-ST elevation acute coronary syndrome.

The effects of rate pressure product at admission on cardiopulmonary function during hospitalization in patients with acute myocardial infarction

OBJECTIVE

This study aimed to analyze the correlation between the rate pressure product (RPP) and cardiopulmonary function during hospitalization in patients with acute myocardial infarction (AMI).

METHODS

A total of 362 patients with AMI were selected for the study, and the median admission RPP was used as the cutoff point to divide the patients into a low-RPP group (n = 181) and a high-RPP group (n = 181). The relationship between the RPP at admission and the cardiopulmonary function during hospitalization was analyzed.

RESULTS

The patients in the high-RPP group had a higher body mass index (BMI) (p = 0.014), a higher prevalence of combined hypertension and diabetes mellitus (p < 0.001), a lower incidence of smoking (p = 0.044), and a higher incidence of oscillatory ventilation (6.1% vs. 1.7%, p = 0.029). The differences in RPP at rest, during warm-up, and within 1 and 4 minutes of recovery were statistically significant between the two groups (p < 0.01 on each occasion), while the differences in anaerobic threshold (AT) and watt max (Max) were not statistically significant (p > 0.05 for both). The patients in the low-RPP group had higher oxygen uptake (VO2 [AT]: 14.9 ± 3.4 vs. 14.2 ± 3.6, p = 0.048) and (VO2peak [Max]:18.2 ± 3.8 vs. 17.3 ± 3.8, p = 0.020). The RPP at admission was negatively correlated with VO2 (AT) and VO2peak (p < 0.05) using the regression Equation VO2peak = 33.682 + (-0.012 * RPP at admission/100) + (-0.105 * Age) + (-0.350 * BMI), while there was no correlation between the RPP at admission and VO2 (AT) (p = 0.149).

CONCLUSION

The RPP at admission was negatively correlated with cardiopulmonary function during hospitalization in patients with AMI. Patients with a high RPP were more likely to have a combination of obesity, hypertension, diabetes mellitus, and reduced oxygen uptake during exercise, while a high RPP at admission appeared to affect their cardiovascular response indicators during exercise.

Deep learning prediction of quantitative coronary angiography values using myocardial perfusion images with a CZT camera

PURPOSE

Evaluate the prediction of quantitative coronary angiography (QCA) values from MPI, by means of deep learning.

METHODS

546 patients (67% men) undergoing stress 99mTc-tetrofosmin MPI in a CZT camera in the upright and supine position were included (1092 MPIs). Patients were divided into two groups: ICA group included 271 patients who performed an ICA within 6 months of MPI and a control group with 275 patients with low pre-test probability for CAD and a normal MPI. QCA analyses were performed using radiologic software and verified by an expert reader. Left ventricular myocardium was segmented using clinical nuclear cardiology software and verified by an expert reader. A deep learning model was trained using a double cross-validation scheme such that all data could be used as test data as well.

RESULTS

Area under the receiver-operating characteristic curve for the prediction of QCA, with > 50% narrowing of the artery, by deep learning for the external test cohort: per patient 85% [95% confidence interval (CI) 84%-87%] and per vessel; LAD 74% (CI 72%-76%), RCA 85% (CI 83%-86%), LCx 81% (CI 78%-84%), and average 80% (CI 77%-83%).

CONCLUSION

Deep learning can predict the presence of different QCA percentages of coronary artery stenosis from MPIs.

Coronary physiology in the catheterisation laboratory: an A to Z practical guide

Coronary revascularisation, either percutaneous or surgical, aims to improve coronary flow and relieve myocardial ischaemia. The decision-making process in patients with coronary artery disease (CAD) remains largely based on invasive coronary angiography (ICA), even though until recently ICA could not assess the functional significance of coronary artery stenoses. Invasive wire-based approaches for physiological evaluations were developed to properly assess the ischaemic relevance of epicardial CAD. Fractional flow reserve (FFR) and later, instantaneous wave-free ratio (iFR), were shown to improve clinical outcomes in several patient subsets when used for coronary revascularisation guidance or deferral and for procedural optimisation of percutaneous coronary intervention (PCI) results. Despite accumulating evidence and positive guideline recommendations, the adoption of invasive physiology has remained quite low, mainly due to technical and economic issues as well as to operator-resistance to change. Coronary image-based computational physiology has been recently developed, with promising results in terms of accuracy and a reduction in computational time, costs, radiation exposure and risks for the patient. Lastly, the integration of intracoronary imaging and physiology allows for individualised PCI treatment, aiming at complete relief of ischaemia through optimised morpho-functional immediate procedural results. Instead of a conventional state-of-the-art review, this A to Z dictionary attempts to provide a practical guide for the application of coronary physiology in the catheterisation laboratory, exploring several methods, their pitfalls, and useful tips and tricks.

Fractional Flow Reserve Versus Instantaneous Wave-Free Ratio in Assessment of Lesion Hemodynamic Significance and Explanation of their Discrepancies. International, Multicenter and Prospective Trial: The FiGARO Study

Background

The FiGARO (FFR versus iFR in Assessment of Hemodynamic Lesion Significance, and an Explanation of Their Discrepancies) trial is a prospective registry searching for predictors of fractional flow reserve/instantaneous wave‐free ratio (FFR/iFR) discrepancy.

Methods and Results

FFR/iFR were analyzed using a Verrata wire, and coronary flow reserve was analyzed using a Combomap machine (both Philips‐Volcano). The risk polymorphisms for endothelial nitric oxide synthase and for heme oxygenase‐1 were analyzed. In total, 1884 FFR/iFR measurements from 1564 patients were included. The FFR/iFR discrepancy occurred in 393 measurements (20.9%): FFRp (positive)/iFRn (negative) type (264 lesions, 14.0%) and FFRn/iFRp (129 lesions, 6.8%) type. Coronary flow reserve was measured in 343 lesions, correlating better with iFR (R=0.56, P<0.0001) than FFR (R=0.36, P<0.0001). The coronary flow reserve value in FFRp/iFRn lesions (2.24±0.7) was significantly higher compared with both FFRp/iFRp (1.39±0.36), and FFRn/iFRn lesions (1.8±0.64, P<0.0001). Multivariable logistic regression analysis confirmed (1) sex, age, and lesion location in the right coronary artery as predictors for FFRp/iFRn discrepancy; and (2) hemoglobin level, smoking, and renal insufficiency as predictors for FFRn/iFRp discrepancy. The FFRn/iFRp type of discrepancy was significantly more frequent in patients with both risk types of polymorphisms (endothelial nitric oxide synthase_r+heme oxygenase‐1_r): 8 patients (24.2%) compared with FFRp/iFRn type of discrepancy: 2 patients (5.9%), P=0.03.

Conclusions

Predictors for FFRp/iFRn discrepancy were sex, age, and location in the right coronary artery. Predictors for FFRn/iFRp were hemoglobin level, smoking, and renal insufficiency. The risk type of polymorphism in endothelial nitric oxide synthase and heme oxygenase‐1 genes was more frequently found in patients with FFRn/iFRp type of discrepancy.

Registration

URL: https://clinicaltrials.gov; Unique identifier: NCT03033810.

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.