Functional Significance Of Coronary Lesions Research Articles

The relationship between triglyceride/high-density lipoprotein cholesterol ratio and the functional significance of coronary lesions

Aims: Have shown that triglycerides (TG) are an independent risk factor for cardiovascular disease (CVD). Dyslipidemia characterized by low high-density lipoprotein cholesterol (HDL-C) has been shown to be associated with symptoms of coronary artery disease (CAD). In studies, the TG/HDL-C ratio has been found to be strongly associated with parameters indicative of the severity of coronary disease. In this study, we aimed to investigate whether the TG/HDL-C ratio is associated with the functional significance of moderate coronary artery lesions. Methods: A total of 102 consecutive patients, 72 male and 30 female, who underwent measurement of fractional flow reserve (FFR) due to moderate coronary stenosis (quantitative coronary analysis 40-70%) on angiography were included in the study. An FFR value ≤0.80 was accepted for hemodynamic significance. Results: Among the 102 patients included in the study, it was determined that 52 (50.9%) had significant functional stenosis. Left ventricular ejection fraction of Group II was lower than Group I (60 (55-62.5) vs. 55(50-60), p=0.006). The male patient ratio was higher in Group II, but the difference between the two groups was not significant (68% and 77%, respectively, p=0.072). Univariate and multivariate logistic regression analysis showed that TG/HDL-C (OR=1.278, 95% CI=1.078-1.514, p=0.005) was an independent determinant of significant functional stenosis. ROC analysis revealed that the TG/HDL-C value was 3.89 and provided 64% specificity and 61.5% sensitivity in predicting hemodynamically significant coronary artery stenosis. Conclusion: Elevated TG/HDL-C values are associated with the functional significance of angiographically moderate coronary artery stenosis.

Diagnostic performance of quantitative flow ratio, non-hyperaemic pressure indices and fractional flow reserve for the assessment of coronary lesions in severe aortic stenosis.

Quantitative flow ratio (QFR) may be used to assess the functional significance of coronary lesions. Only limited validation exists for this technology in the setting of severe aortic stenosis. A prospective study was performed on patients who were being considered for transcatheter aortic valve implantation. QFR analysis was performed (Medis Medical Imaging System, Leiden, The Netherlands) and compared to invasive measurements of haemodynamic assessment [fractional flow reserve (FFR), instantaneous wave-free ratio (iFR), diastolic pressure ratio during the wave-free period (dPR) and distal arterial pressure/arterial pressure (Pd/Pa)]. A total of 35 patients were included in the study. Mean age was 75.5±6.5 and mean aortic valve gradient was 44.3±11.8 mmHg. There were 57 vessels analysed. The mean FFR was 0.83±0.10 and 22 vessels (39%) had a functionally significant FFR ≤0.80. QFR demonstrated a discriminatory power to predict functionally significant FFR [area under the receiver operating characteristic curve (AUC), 0.92; 95% confidence interval (CI): 0.84 to 1.00], representing a sensitivity of 73%, specificity of 91%, positive predictive value of 84%, negative predictive value of 84% and an accuracy of 84%. QFR also demonstrated a discriminatory power to predict functionally significant iFR ≤0.89 (AUC =0.92; 95% CI: 0.85 to 0.99), dPR ≤0.89 (AUC =0.90; 95% CI: 0.83 to 0.98) and Pd/Pa ≤0.92 (AUC =0.89; 95% CI: 0.80 to 0.97). QFR demonstrates acceptable diagnostic performance in patients with severe aortic stenosis when both FFR and non-hyperaemic pressure indices are used as reference standards.

Effect of Patient-Specific Coronary Flow Reserve Values on the Accuracy of MRI-Based Virtual Fractional Flow Reserve.

The purpose of this study is to investigate the effect of varying coronary flow reserve (CFR) values on the calculation of computationally-derived fractional flow reserve (FFR). CFR reflects both vessel resistance due to an epicardial stenosis, and resistance in the distal microvascular tissue. Patients may have a wide range of CFR related to the tissue substrate that is independent of epicardial stenosis levels. Most computationally based virtual FFR values such as FFRCT do not measure patient specific CFR values but use a population-average value to create hyperemic flow conditions. In this study, a coronary arterial computational geometry was constructed using magnetic resonance angiography (MRA) data acquired in a patient with moderate CAD. Coronary flow waveforms under rest and stress conditions were acquired in 13 patients with phase-contrast magnetic resonance (PCMR) to calculate CFR, and these flow waveforms and CFR values were applied as inlet flow boundary conditions to determine FFR based on computational fluid dynamics (CFD) simulations. The stress flow waveform gave a measure of the functional significance of the vessel when evaluated with the physiologically-accurate behavior with the patient-specific CFR. The resting flow waveform was then scaled by a series of CFR values determined in the 13 patients to simulate how hyperemic flow and CFR affects FFR values. We found that FFR values calculated using non–patient-specific CFR values did not accurately predict those calculated with the true hyperemic flow waveform. This indicates that both patient-specific anatomic and flow information are required to accurately non-invasively assess the functional significance of coronary lesions.

Functional Assessment of Coronary Artery Lesions-Old and New Kids on the Block.

Angiography is inaccurate in assessing functional significance of coronary lesions, and often stenoses deemed severe on angiographic assessment do not restrict coronary blood flow at rest or with maximal dilatation. Angiography-guided revascularization has not shown improvement in hard clinical outcomes in stable ischemic heart disease (SIHD). Most current guidelines for SIHD recommend invasive functional assessment of lesions to guide revascularization if prior evidence of ischemia is not available. There has been several recent advances and development of novel methods in this arena. Various contemporary clinical trials have been undertaken for validation of these indices. Here we review the physiological basis, tools, techniques, and evidence base for various invasive (resting as well as hyperemic) and noninvasive methods for functional assessment of coronary lesions. Left main stenosis, bifurcation lesions, serial stenosis, and acute coronary syndrome each causes unique disequilibrium that may affect measurements and require special considerations for accurate functional assessment.

P2702Assessment of endothelial shear stress and functional significance of coronary lesions by computed tomography coronary angiography (CTCA) and computational fluid dynamics: a comparison with PET

Abstract Background The feasibility of assessing endothelial shear stress (ESS) in coronary lesions by non-invasive imaging and its potential role in different clinical settings has been recently explored. However, the relationship of ESS with functional indices derived by computed tomography coronary angiography (CTCA) and its value in predicting perfusion changes by quantitative positron emission tomography (PET) downstream stenotic vessels has not been assessed. Purpose To investigate the feasibility of calculating local ESS, its relationship with stenosis severity as well as with virtual functional assessment index (vFAI), and the comparative performance of the two parameters for predicting impaired coronary vasodilating capability in terms both of stress myocardial blood flow (MBF) and myocardial flow reserve (MFR) in patients submitted to CTCA. Methods Thirty-two patients (23 male-9 female, mean age 65.6±7.2 years) with intermediate pre-test likelihood of coronary artery disease (CAD), who were enrolled in the EVINCI and SMARTool projects, and had undergone CTCA with vFAI and PET myocardial perfusion imaging with 15 O-water or 13 N-ammonia were included in the study. PET was considered positive when >1 contiguous segments showed both stress MBF ≤2.3 mL/g/min and MFR ≤2.5 for 15 O-water or ≤1.79 mL/g/min and ≤2.0, for 13 N-ammonia respectively. A vFAI threshold of 0.85 was used as predictor of impaired vasodilating capability. ESS computation was based on a mean aortic pressure of 100 mmHg for the inlet and a mean blood flow at rest of 0.00105 kg/s for the outlet. ESS was calculated (Pa) in the full length of the stenosis and the mean value was obtained. Results Hybrid imaging analysis was performed in CTCA and PET datasets. 51 coronary segments were assessed. There were 27 lesions with stenosis 31–50% and 24 lesions with stenosis 51–70%. ESS was higher in the latter (20.4, IQ: 11.4–32.1 vs. 10.4, IQ: 5.5–15.7, p=0.04). Similarly, ESS was higher in stenoses with impaired vasodilating capacity compared to those without, although this difference did not reach statistical significance (22.8, IQ: 13.2–35.1 vs. 10.6, IQ: 5.7–22.1, p=0.10). The ROC curve analysis for prediction of both abnormal stress MBF and MFR followed the same pattern (AUC=0.668, 95% confidence interval (CI): 0.490–0.810, p=0.11).On the other hand, there was a moderate negative correlation (r=−0.41, p=0.004) between ESS and vFAI and the former was lower in stenoses with vFAI >0.85 compared to those below this threshold (7.35, IQ: 3.2–13.9 vs. 19.1, IQ: 14.1–32.8, p=0.012). vFAI was a good predictor of coronary flow capacity (AUC=0.737, CI: 0.58–0.85, p=0.02). Conclusion Calculation of ESS is feasible in CTCA datasets. ESS was related with stenosis severity and there was a trend to be higher in lesions with impaired coronary vasodilating capability. ESS is modestly related with vFAI and may also be an additional predictor of impaired regional myocardial flow obtained by PET imaging. Acknowledgement/Funding This study has received funding from the EU H2020 research and innovation programme under grant agreement No 689068 and from p-Med GR 5002802

The influence of model order reduction on the computed fractional flow reserve using parameterized coronary geometries

Computational fluid dynamics (CFD) models combined with patient-specific imaging data are used to non-invasively predict functional significance of coronary lesions. This approach to predict the fractional flow reserve (FFR) is shown to have a high diagnostic accuracy when comparing against invasively measured FFR. However, one of the main drawbacks is the high computational effort needed for preprocessing and computations. Hence, uncertainty quantification may become unfeasible. Reduction of complexity is desirable, computationally inexpensive models with high diagnostic accuracy are preferred. We present a parametric comparison study for three types of CFD models (2D axisymmetric, Semi-3D and 3D) in which we study the impact of model reduction on three models on the predicted FFR. In total 200 coronary geometries were generated for seven geometrical characteristics e.g. stenosis severity, stenosis length and vessel curvature. The effect of time-averaged flow was investigated using unsteady, mean steady and a root mean square (RMS) steady flow. The 3D unsteady model was regarded as reference model. Results show that when using an unsteady or RMS flow, predicted FFR hardly varies between models contrary to using average flows. The 2D model with RMS flow has a high diagnostic accuracy (0.99), reduces computational time by a factor 162,000 and the introduced model error is well below the clinical relevant differences. Stenosis severity, length, curvature and tapering cause most discrepancies when using a lower order model. An uncertainty analysis showed that this can be explained by the low variability that is caused by variations in stenosis asymmetry.

Plaque imaging with CT-a comprehensive review on coronary CT angiography based risk assessment.

CT based technologies have evolved considerably in recent years. Coronary CT angiography (CTA) provides robust assessment of coronary artery disease (CAD). Early coronary CTA imaging-as a gate-keeper of invasive angiography-has focused on the presence of obstructive stenosis. Coronary CTA is currently the only non-invasive imaging modality for the evaluation of non-obstructive CAD, which has been shown to contribute to adverse cardiac events. Importantly, improved spatial resolution of CT scanners and novel image reconstruction algorithms enable the quantification and characterization of atherosclerotic plaques. State-of-the-art CT imaging can therefore reliably assess the extent of CAD and differentiate between various plaque features. Recent studies have demonstrated the incremental prognostic value of adverse plaque features over luminal stenosis. Comprehensive coronary plaque assessment holds potential to significantly improve individual risk assessment incorporating adverse plaque characteristics, the extent and severity of atherosclerotic plaque burden. As a result, several coronary CTA based composite risk scores have been proposed recently to determine patients at high risk for adverse events. Coronary CTA became a promising modality for the evaluation of functional significance of coronary lesions using CT derived fractional flow reserve (FFR-CT) and/or rest/dynamic myocardial CT perfusion. This could lead to substantial reduction in unnecessary invasive catheterization procedures and provide information on ischemic burden of CAD. Discordance between the degree of stenosis and ischemia has been recognized in clinical landmark trials using invasive FFR. Both lesion stenosis and composition are possibly related to myocardial ischemia. The evaluation of lesion-specific ischemia using combined functional and morphological plaque information could ultimately improve the diagnostic performance of CTA and thus patient care. In this review we aimed to summarize current evidence on comprehensive coronary artery plaque assessment using coronary CTA.

Comparison of Accuracy of One-Use Methods for Calculating Fractional Flow Reserve by Intravascular Optical Coherence Tomography to That Determined by the Pressure-Wire Method

Although the identification of the hemodynamic significance of coronary lesions becomes important for revascularization strategy, the potential role of 3-dimensional high-resolution intracoronary optical coherence tomography (OCT) for predicting functional significance of coronary lesions remains unclear. We assessed the diagnostic performance of 2 computational approaches for deriving fractional flow reserve (FFR) from intravascular OCT images. We developed 2 methods to derive FFR-OCT by AFD (FFR-OCTAFD) and FFR-OCT by CFD (FFR-OCTCFD). Among 217 eligible patients between 2011 and 2014, 104 were included for data analysis (9 for derivation, 95 for validation). Luminal geometries from 3-dimensional OCT were used for both FFR-OCTAFD and FFR-OCTCFD calculations. The analytical fluid dynamics method calculated FFR from the blood flow resistance estimated using Poiseuille's law. For computational fluid dynamics, we numerically solved the Navier-Stokes equation in a steady-state flow with the distal porous media model for the capillary vessels. We examined the diagnostic performance of FFR-OCTAFD and FFR-OCTCFD compared with the pressure-wire measured FFR. The accuracy, sensitivity, specificity, PPV, and NPV were 86%, 65%, 94%, 81%, and 88% for FFR-OCTAFD and 86%, 73%, 91%, 76%, and 90% for FFR-OCTCFD. The area under the curve of the receiver-operating characteristic curve was 0.88 for FFR-OCTAFD and 0.86 for FFR-OCTCFD. FFR-OCTAFD and FFR-OCTCFD showed a strong linear correlation with the measured FFR (r = 0.631; p <0.001, r = 0.655; p <0.001, respectively). FFR derived from high-resolution volumetric OCT images showed high diagnostic performance for the detection of coronary ischemia. In conclusion, OCT-derived FFR may be useful for guiding the management of coronary artery disease.

The relationship between fragmented QRS and functional significance of coronary lesions

BackgroundRecently fragmented QRS (fQRS) on electrocardiography (ECG) has been introduced as a predictor of myocardial scarring and myocardial ischemia in coronary artery disease (CAD). ObjectiveThe aim of this study was to investigate the relationship between fQRS and fractional flow reserve (FFR) results in patients with the intermediate degree of coronary artery stenosis. MethodsA total of 301 consecutive patients who underwent coronary angiography (CAG) and FFR measurement for intermediate coronary artery stenosis were included in the study. The study patients were divided into two groups: the low FFR group (FFR value of ≤0.80) and normal FFR (FFR value of >0.80) group. Both groups were compared in terms of the presence of fQRS. ResultsOf 301 patients, fQRS was detected in 128 (42.5%) and low FFR was detected in 115 (38.2%). In the low FFR group, fQRS was significantly higher (P<0.001). Multivariate analysis showed that fQRS was an independent predictor of myocardial ischemia in patients with intermediate coronary stenosis (OR=7.202, CI 95%, 4.195–12.367; p<0.001). The presence of fQRS had 70% sensitivity and 74% specificity for the prediction of FFR≤0.80. ConclusionIn clinical practice, the presence of fQRS on ECG is associated with myocardial ischemia in patients with intermediate coronary stenosis.

Factors Associated With Errors in Visual Estimation of the Functional Significance of Coronary Lesions

Introduction and objectivesVisual angiographic assessment continues to be used when decisions are made on whether to revascularize ambiguous coronary lesions. Multiple factors, other than the degree of stenosis, have been associated with the functional significance of a coronary lesion. The aim of this study was to investigate the ability of interventionists to visually predict the functional significance of a coronary lesion and the clinical and angiographic characteristics associated with errors in prediction. MethodsWe conducted a concordance study of the functional significance of coronary lesions predicted by experienced interventionists and fractional flow reserve values measured by intracoronary pressure wire in 665 intermediate lesions (40%-70% diameter stenosis) in 587 patients. We determined which factors were independently associated with errors in prediction. ResultsThere was disagreement between the predicted fractional flow reserve value of ≤ 0.80 and the observed value in 30.1% of the lesions (overestimation: 11.3%; underestimation, 18.8%). Stent location in an artery other than the anterior descending artery or in a bifurcation was associated with overestimation. Male sex, severe calcification, and a greater myocardial territory distal to the lesion were significantly associated with the functional significance of the underestimated lesion. ConclusionsEven when taking into account angiographic and clinical characteristics, there is a high rate of disagreement between visual estimation and direct measurement of intermediate coronary stenosis in relation to its functional significance. Specific angiographic and clinical characteristics are associated with an increased tendency to overestimate or underestimate the significance of lesions.

Factores asociados al error en la estimación visual de la importancia funcional de lesiones coronarias

Introduction and objectivesVisual angiographic assessment continues to be used when decisions are made on whether to revascularize ambiguous coronary lesions. Multiple factors, other than the degree of stenosis, have been associated with the functional significance of a coronary lesion. The aim of this study was to investigate the ability of interventionists to visually predict the functional significance of a coronary lesion and the clinical and angiographic characteristics associated with errors in prediction. MethodsWe conducted a concordance study of the functional significance of coronary lesions predicted by experienced interventionists and fractional flow reserve values measured by intracoronary pressure wire in 665 intermediate lesions (40%-70% diameter stenosis) in 587 patients. We determined which factors were independently associated with errors in prediction. ResultsThere was disagreement between the predicted fractional flow reserve value of ≤ 0.80 and the observed value in 30.1% of the lesions (overestimation: 11.3%; underestimation, 18.8%). Stent location in an artery other than the anterior descending artery or in a bifurcation was associated with overestimation. Male sex, severe calcification, and a greater myocardial territory distal to the lesion were significantly associated with the functional significance of the underestimated lesion. ConclusionsEven when taking into account angiographic and clinical characteristics, there is a high rate of disagreement between visual estimation and direct measurement of intermediate coronary stenosis in relation to its functional significance. Specific angiographic and clinical characteristics are associated with an increased tendency to overestimate or underestimate the significance of lesions.Full English text available from:www.revespcardiol.org/en

Coronary Flow Velocity Reserve Assessment with Transthoracic Doppler Echocardiography.

Coronary flow velocity reserve (CFVR) reflects global coronary atherosclerotic burden, endothelial function and state of the microvasculature. It could be measured using transthoracic Doppler echocardiography in a non-invasive, feasible, reliable and reproducible fashion, following a standardised protocol with different vasodilatory stimuli. CFVR measurement is a recommended complement to vasodilator stress echocardiography. It could serve as a diagnostic tool for coronary microvascular dysfunction and in the setting of epicardial coronary artery stenoses could help in identification and assessment of functional significance of coronary lesions and follow-up of patients after coronary interventions. CFVR has also a prognostic significance in different clinical situations.

Long-term follow-up of patients with deferred coronary intervention guided by measurement of fractional flow reserve

Introduction and AimsThe functional significance of coronary lesions can be assessed in the cardiac catheterization laboratory by determination of fractional flow reserve (FFR), thus overcoming one of the major limitations of conventional angiography. The aim of this study was to analyze the long-term clinical course of patients with intermediate coronary stenosis (50–70%) deferred for intervention based on FFR <0.80. MethodsBetween May 1999 and December 2009, 300 lesions in 231 patients (mean age 65±10 years, 68% male and 75.3% with multivessel disease) were studied by FFR. Intervention was deferred in 282 (94%) lesions and 18 were treated based on FFR <0.80. We assessed the occurrence of major adverse cardiovascular events (MACE), defined as cardiovascular death, non-fatal acute coronary syndrome and target lesion revascularization (TLR). ResultsDuring a median follow-up of 637 days (interquartile range 455–1160), there were 15 (6.5%) MACE in the subgroup of patients with target lesion intervention deferred based on FFR: one cardiovascular death, four hospitalizations for acute coronary syndrome and 14 TLR (12 patients were treated percutaneously and two underwent coronary artery bypass grafting). MACE-free survival at one year follow-up was 97.8%. ConclusionThese results, in a real-world population, support the current trend to base the decision to treat on functional rather than purely anatomical criteria, in order to improve safety and efficiency.

Seguimento clínico a longo prazo de doentes com intervenção coronária diferida guiada pela medição da fração de fluxo de reserva coronária

Introduction and aimsThe functional significance of coronary lesions can be assessed in the cardiac catheterization laboratory by determination of fractional flow reserve (FFR), thus overcoming one of the major limitations of conventional angiography. The aim of this study was to analyze the long-term clinical course of patients with intermediate coronary stenosis (50-70%) deferred for intervention based on FFR <0.80. MethodsBetween May 1999 and December 2009, 300 lesions in 231 patients (mean age 65±10 years, 68% male and 75.3% with multivessel disease) were studied by FFR. Intervention was deferred in 282 (94%) lesions and 18 were treated based on FFR <0.80. We assessed the occurrence of major adverse cardiovascular events (MACE), defined as cardiovascular death, non-fatal acute coronary syndrome and target lesion revascularization (TLR). ResultsDuring a median follow-up of 637 days (interquartile range 455-1160), there were 15 (6.5%) MACE in the subgroup of patients with target lesion intervention deferred based on FFR: one cardiovascular death, four hospitalizations for acute coronary syndrome and 14 TLR (12 patients were treated percutaneously and two underwent coronary artery bypass grafting). MACE-free survival at one year follow-up was 97.8%. ConclusionThese results, in a real-world population, support the current trend to base the decision to treat on functional rather than purely anatomical criteria, in order to improve safety and efficiency.

TCT-240 Benefits and costs of routine fractional flow reserve assessment in all major epicardial vessels during elective invasive angiography

Fractional flow reserve (FFR) is commonly reserved to assess the functional significance of coronary lesions with intermediate stenoses. We sought to determine the benefits and costs of routine FFR assessment in all major epicardial vessels during elective invasive coronary angiography (IA). 144

Myocardial perfusion imaging and infarct characterization using multidetector cardiac computed tomography

Until recently, computed tomography coronary angiography was restricted to the anatomical assessment of coronary stenosis, whereas the functional significance of coronary lesions remained outside of its scope. Nevertheless, the kinetics of iodinated contrast is similar to gadolinium-diethylenetriamine pentaacetic acid used in contrast-enhanced magnetic resonance imaging, allowing assessment of myocardial perfusion and viability by cardiac computed tomography.

Low radiation dose imaging of myocardial perfusion and coronary angiography with a hybrid PET/CT scanner

Objectives:To test the image quality and feasibility of a sequential low radiation dose protocol for hybrid cardiac PET/CT angiography (CTA).Background:Multidetector computed tomography (MDCT) is a non-invasive method for coronary angiography. The negative predictive value of MDCT is high but perfusion imaging has a role in detecting functional significance of coronary lesions. This has encouraged combining these techniques. However, radiation dose is of concern. We report our first experiences with a low dose sequential CTA mode applicable to hybrid imaging.Methods:In the first phase, 10 consecutive cardiac MDCT angiographies were performed with spiral acquisition and compared in terms of image quality and dose with the following 10 patients performed with a new sequential mode. In the second phase, feasibility and radiation dose of a combined 15O-water rest-stress PET perfusion/sequential CTA protocol were assessed in another group of 61 consecutive patients.Results:Mean effective radiation dose was 60% lower in the sequential group than in the spiral group (19·3 versus 7·6 mSv, P<0·001). In the second phase, the new sequential hybrid protocol proved possible in 87% of the patients given the preconditions determined by the manufacturer. Mean effective dose of the CT acquisition was 7·6 mSv and total dose from the PET/CTA hybrid study 9·5 mSv.Conclusion:Low dose PET/CT allows cardiac hybrid studies with <10 mSv. The protocol can be applied to almost nine out of 10 patients with CT image quality comparable to spiral acquisition.

Meta-Analysis of Fractional Flow Reserve Versus Quantitative Coronary Angiography and Noninvasive Imaging for Evaluation of Myocardial Ischemia

We performed a meta-analysis of 31 studies comparing the results of fractional flow reserve (FFR) against quantitative coronary angiography (QCA) and/or noninvasive imaging of the same lesions. Studies were retrieved from PubMed (last search February 2006). Across 18 studies (1,522 lesions), QCA had a random effects sensitivity of 78% (95% confidence interval [CI] 67 to 86) and specificity of 51% (95% CI 40 to 61) against FFR (0.75 cutoff). Overall concordances were 61% for lesions with diameter stenosis 30% to 70%, 67% for stenoses >70%, and 95% for stenoses <30%. Compared with noninvasive imaging (21 studies, 1,249 lesions), FFR had a sensitivity of 76% (95% CI 69 to 82) and specificity of 76% (95% CI 71 to 81) by random effects. Summary receiver-operator characteristic estimates were similar. Most data addressed comparisons with perfusion scintigraphy (976 lesions, sensitivity 75%, specificity 77%), and some data were also available for dobutamine stress echocardiography (273 lesions, sensitivity 82%, specificity 74%). In conclusion, QCA does not predict the functional significance of coronary lesions. FFR shows modest concordance with noninvasive imaging tests. The prognostic implications of discordant FFR and imaging results need further study.

The effect of lesion length on the functional significance of coronary lesions

The effect of lesion length on the functional significance of coronary lesions

Incremental doses of intracoronary adenosine for the assessment of coronary velocity reserve for clinical decision making

Achievement of maximal vasodilatation of the coronary microcirculation is a prerequisite for the measurement of coronary flow reserve (CFR). The present study was designed to address the hypothesis that intracoronary adenosine yields more complete vasodilation of the coronary microcirculation when incremental doses are used, resulting in higher and more accurate coronary flow reserve measurements. Four hundred and fifty-seven patients were divided in two groups; group I (319 patients) comprised patients without angiographic evidence of significant coronary artery disease, while group II (138 patients) comprised patients with intermediate coronary stenoses (between 40% and 70% diameter stenosis). Coronary velocity reserve (CVR, a surrogate measurement for CFR) was measured during cardiac catheterization using a Doppler-tipped guidewire. Incremental doses of intracoronary adenosine (12 to 54 microg for the left coronary artery and 6 to 42 microg for the right coronary artery) were administered. There was a significant difference between the initial dose of adenosine and the subsequent incremental doses. Of a total of 479 observations, only 192 (40%) had the maximal CVR value at the first dose. Thirty-nine percent of the patients in group I and 27% in group II with an initial CVR value < 2.5 increased CVR to > or = 2.5 with incremental doses of adenosine. This study suggests that incremental doses of adenosine should be used to achieve maximal CVR for the assessment of the functional significance of coronary lesions. Cathet Cardiovasc Intervent 2001;54:34-40.