Significance Of Intermediate Coronary Lesions Research Articles

Functional significance of intermediate coronary lesions in patients with stable coronary artery disease

Functional significance of intermediate coronary lesions in patients with stable coronary artery disease

Contemporary Use of Coronary Physiology in Cardiology.

Coronary angiography has a limited ability to predict the functional significance of intermediate coronary lesions. Hence, physiological assessment of coronary lesions, via fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR), has been introduced to determine their functional significance. An accumulating body of evidence has consolidated the role of physiology-guided revascularization, particularly among patients with stable ischemic heart disease. The use of FFR or iFR to guide decision-making in patients with stable ischemic heart disease and intermediate coronary lesions received a class I recommendation from major societal guidelines. Nevertheless, the role of coronary physiology testing is less clear among certain patients' groups, including patients with serial coronary lesions, acute coronary syndromes, aortic stenosis, heart failure, as well as post-percutaneous coronary interventions. In this review, we aimed to discuss the utility and clinical evidence of coronary physiology (mainly FFR and iFR), with emphasis on those specific patient groups.

Myocardial perfusion imaging by single-photon emission tomography (MPI SPECT) versus Instantaneous wave-free ratio (IFR) for assessment of functional significance of intermediate coronary artery lesions

BackgroundThe aim of our work was to compare the myocardial perfusion imaging by single-photon emission tomography (MPI-SPECT) as a non-invasive, relatively non-expensive test versus the instantaneous wave-free ratio (IFR) for the evaluation of functional significance of the borderline coronary artery lesions in the view of results of fractional flow reserve (FFR) which is considered the gold standard reference test.ResultsOur study was conducted in the Cardiology Department. It included 50 patients with borderline coronary artery lesions; they underwent physiological evaluation by stress/rest myocardial perfusion imaging using followed by an invasive physiological assessment by Instantaneous wave-free ratio (IFR) and Fractional flow reserve (FFR). Finally, the results of both SPECT MPI and IFR were compared to FFR as a gold standard reference. There was a strong (kappa = 0.754) significant (P value < 0.001) agreement between the MPI results and FFR results and the overall agreement was 88%. The sensitivity of the MPI was 81.8%, the specificity was 92.9%, the positive predictive value was 90%, the negative predictive value was 86.7%, the positive likelihood ratio was 11.45, and the negative likelihood ratio was 0.20. There was a strong (kappa = 0.918) significant (P value < 0.001) agreement between the IFR results and FFR results and the overall agreement was 96%. The sensitivity of the IFR was 90.9%, the specificity was 100%, the positive predictive value was 100 %, the negative predictive value was 93.3%, and the negative likelihood ratio was 0.09.ConclusionsThe instantaneous wave-free ratio (IFR) may be a valid alternative to fractional flow reserve to assess the functional significance of intermediate coronary lesions. The myocardial perfusion imaging may be an alternative, non-invasive, relatively non-expensive test for the evaluation of the physiological significance of intermediate coronary lesions.

Coronary Physiology Assessment for the Diagnosis and Treatment of Stable Ischemic Heart Disease.

Coronary artery disease is the most prevalent cardiovascular disease in the USA. In the majority of settings, percutaneous coronary intervention (PCI) for stable coronary artery disease (CAD) reduces angina and improves quality of life; however, it does not improve survival and is associated with infrequent but serious complications. Selection of appropriate patients and coronary lesions for revascularization with PCI is crucial to maximize the benefit-to-risk ratio. The assessment of the hemodynamic significance of intermediate coronary lesions has been shown to improve outcomes and reduce healthcare costs. The current review summarizes the existing evidence regarding the physiological assessment of coronary lesions, with emphasis on fractional flow reserve, the most common invasive hemodynamic assessment modality.

The Impact of Fractional Flow Reserve on Revascularization.

IntroductionFractional flow reserve (FFR) is recommended by society guidelines for assessment of the hemodynamic significance of intermediate coronary lesions when non-invasive evidence of myocardial ischemia is unavailable. However, the prevalence of FFR usage in current practice and how FFR values impact revascularization decisions are not well known.MethodsAt a single-center Veterans Administration Hospital, all subjects referred for coronary angiography for any indication from the period from May 2012 until January 2014 were prospectively entered into a database. FFR was measured in all intermediate coronary lesions (30–70% stenosis). Based on the FFR results, the lesions were categorized into 3 different groups: FFR > 0.80 (non-ischemic), FFR 0.75–0.80 (gray zone), and FFR < 0.75 (ischemic).ResultsA total of 1482 cardiac catheterizations were performed during the study period. FFR was performed in 347 (23%) of these procedures. The total numbers of intermediate coronary lesions evaluated with FFR were 429. The mean FFR value was 0.79 (median = 0.80; interquartile range 0.64–0.96). Among 211 non-ischemic lesions, revascularization was deferred in 201 (95%). In the gray-zone group (73 lesions), 35 (48%) lesions were treated with percutaneous coronary intervention (PCI), 11 (15%) lesions were referred for coronary artery bypass grafting surgery (CABG), and 27 (37%) lesions were treated medically. In the ischemic group (145 lesions), 82 (57%) lesions were treated with PCI, 41 (28%) lesions were referred for CABG, and 22 (15%) lesions were treated medically.ConclusionAt a Veterans Administration Hospital, FFR was performed in approximately one out of four total catheterizations. FFR documented lack of ischemia in about half of the intermediate coronary lesions, and thus reduced the need for many revascularization procedures.Electronic supplementary materialThe online version of this article (doi:10.1007/s40119-015-0051-1) contains supplementary material, which is available to authorized users.

Usefulness of lumen area parameters determined by intravascular ultrasound to predict functional significance of intermediate coronary artery stenosis

Background Coronary artery disease is the leading cause of death in China. Percutaneous coronary intervention is a recent milestone technology for treatment coronary artery disease. However, clinical decision making for patients with intermediate coronary stenosis is still controversial. We designed this study to assess the optimal intravascular ultrasound (IVUS) criteria for predicting functional significance of intermediate coronary lesions. Methods We enrolled 141 patients with 165 intermediate coronary lesions located in vessels with a diameter ≥ 2.50 mm. IVUS of intermediate coronary lesions were performed before intervention. Pressure-derived fractional flow reserve (FFR) was measured at maximal hyperemia induced by adenosine infusion. An FFR &lt;0.80 was considered as abnormal functional significance. Results For the overall 165 lesions, the mean FFR value was 0.84±0.09. The diameter of the stenosis by visual estimation on angiogram was (59.63±11.29)%. Minimum lumen diameter (MLD), minimum lumen area (MLA) and plaque burden (PB) were (2.00±0.36) mm, (3.88±1.34) mm2, (67.28±9.89)% respectively by IVUS measurements. An FFR &lt;0.80 was seen in 43 lesions (30.5%). There was a moderate correlation between IVUS parameters and FFR, including MLD (r=0.372, P &lt;0.001), MLA (r=0.442, P &lt;0.001) and PB (r=-0.172, P &lt;0.05). MLA was a predictor for FFR as a continuous variable independent of possible confounding variables (P &lt;0.05), and MLA and PB, were predictors for FFR &lt;0.80 as binary variables (P &lt;0.05). The best cutoff value of MLA to predict FFR &lt;0.80 was &lt;3.15 mm2, with a 73.6% diagnostic accuracy; sensitivity 71.4%, specificity 67.0%, AUC=0.709, and P &lt;0.001. The cutoff value of the PB to predict FFR &lt;0.80 was 65.45%; sensitivity 82.6%, specificity 41.2%, AUC=0.644, and P &lt;0.01. If both MLA and PB were taken into account, the negative predictive value and the positive predictive value were 88.7% and 64.8% respectively. Conclusions Anatomic measurements of intermediate coronary lesions obtained by IVUS showed a moderate correlation to FFR values. IVUS-derived MLA ≥3.15 mm2 may be useful to exclude FFR &lt;0.80, but poor specificity limits its applicability for physiological assessment of lesions &lt;3.15 mm2. MLA was one of many factors affecting coronary flow hemodynamics. Both MLA and PB should be taken into account when determining functional ischemia.

A Poiseuille-based coronary angiographic index for prediction of fractional flow reserve

BackgroundCoronary revascularization is commonly based on the angiographic finding of percent diameter stenosis (%DS) >50 while lesion length (LL), which contributes to flow-limitation according to Poiseuille's equation, is disregarded. Fractional flow reserve (FFR) is superior to assessment of %DS for identifying flow-limiting lesions, but the technology is invasive and relatively expensive. We developed a Poiseuille-based angiographic index, incorporating both minimal lumen diameter (MLD) and LL, for improved assessment of the hemodynamic significance of intermediate coronary lesions. The present study was designed to test the hypothesis that the Poiseuille-based angiographic index correlated better with FFR measurements than angiographic assessment of %DS. MethodsWe performed quantitative coronary angiography (QCA) and FFR measurements in 46 intermediate coronary lesions in 41 symptomatic patients referred for diagnostic coronary angiography. From QCA we determined LL, MLD and %DS and calculated an angiographic index, the LL/MLD4 ratio. ResultsMean LL was 14.2±7.8 (range: 4.3–38.8) mm, MLD 1.4±0.4 (range: 0.6–2.3) mm, %DS 46±12 (range: 25–74) and FFR 0.85±0.09 (range: 0.55–1.00). Fractional flow reserve correlated inversely with %DS (R=−0.39, p=0.008) and with the LL/MLD4 ratio (R=−0.66, p<0.0001). An FFR cut-off value of 0.80 corresponded with a LL/MLD4 ratio of 12 (p=0.003) but not with a %DS of 50 (p=NS). A LL/MLD4 ratio ≤12 had a specificity of 94% and negative predictive value of 82% for excluding hemodynamically significant lesions with FFR (≥0.80). ConclusionsThe LL/MLD4 ratio was superior to standard angiographic measurement of %DS for exclusion of hemodynamically significant coronary lesions.

VALIDATION OF INTRAVASCULAR ULTRASOUND DERIVED PARAMETERS WITH FRACTIONAL FLOW RESERVE FOR ASSESSMENT OF CORONARY STENOSIS SEVERITY

Background—We assessed optimal intravascular ultrasound (IVUS) criteria for predicting functional significance of intermediate coronary lesions. Methods and Results—Overall, 201 patients with 236 coronary lesions underwent IVUS and invasive physiological assessment before intervention. Fractional flow reserve (FFR) was measured at maximal hyperemia induced by intravenous adenosine infusion. FFR <0.80 at maximum hyperemia was seen in 49 (21%) of the overall 236 lesions. The independent determinants of FFR were minimal lumen area (MLA; β=0.020; 95% confidence interval [CI], 0.008 to 0.031; P=0.032), plaque burden (β=−0.002; 95% CI, −0.003 to 0.001; P=0.001), lesion length with a lumen area <3.0 mm2 (β=−0.003; 95% CI, −0.005 to −0.001; P=0.005), and left anterior descending artery location (β=−0.035; 95% CI, −0.055 to −0.016; P=0.001). The best cutoff value (with a maximal accuracy) of the MLA to predict FFR <0.80 was <2.4 mm2, with a diagnostic accuracy of 68% (90% sensitivity, 60% specificity, and area und...

Validation of Intravascular Ultrasound–Derived Parameters With Fractional Flow Reserve for Assessment of Coronary Stenosis Severity

We assessed optimal intravascular ultrasound (IVUS) criteria for predicting functional significance of intermediate coronary lesions. Overall, 201 patients with 236 coronary lesions underwent IVUS and invasive physiological assessment before intervention. Fractional flow reserve (FFR) was measured at maximal hyperemia induced by intravenous adenosine infusion. FFR <0.80 at maximum hyperemia was seen in 49 (21%) of the overall 236 lesions. The independent determinants of FFR were minimal lumen area (MLA; β=0.020; 95% confidence interval [CI], 0.008 to 0.031; P=0.032), plaque burden (β=-0.002; 95% CI, -0.003 to 0.001; P=0.001), lesion length with a lumen area <3.0 mm(2) (β=-0.003; 95% CI, -0.005 to -0.001; P=0.005), and left anterior descending artery location (β=-0.035; 95% CI, -0.055 to -0.016; P=0.001). The best cutoff value (with a maximal accuracy) of the MLA to predict FFR <0.80 was <2.4 mm(2), with a diagnostic accuracy of 68% (90% sensitivity, 60% specificity, and area under the curve=0.800; 95% CI, 0.742 to 0.848; P<0.001). The cutoff value of plaque burden to predict FFR <0.80 was ≥79% (69% sensitivity, 72% specificity, and area under the curve=0.756; 95% CI, 0.696 to 0.810; P<0.001). The cutoff value of lesion length with a lumen area <3.0 mm(2) was 3.1 mm (84%sensitivity, 63%specificity, and area under the curve=0.765; 95% CI, 0.706 to 0.818; P<0.001). Among 117 lesions with an MLA ≥2.4 mm(2), 112 (96%) had an FFR ≥0.80,; and all but 1 showed FFR ≥0.75. Conversely, 44 (37%) lesions with an MLA <2.4 mm(2) had an FFR <0.80. IVUS-derived MLA ≥2.4 mm(2) may be useful to exclude FFR <0.80, but poor specificity limits its value for physiological assessment of lesions with MLA <2.4 mm(2). Thus, FFR or stress tests may be necessary to accurately identify ischemia-inducible intermediate stenoses.

Determination of haemodynamic significance of intermediate coronary lesions using three-dimensional coronary reconstruction

This study evaluates three-dimensional (3-D) reconstruction of the coronary arteries in assessment of angiographically borderline lesions. Three-dimensional (3-D) quantitative coronary angiography (QCA) was performed for 41 intermediate coronary stenotic lesions (IL) in 31 patients. Measurements of cross-sectional stenosis (CSS), diameter stenosis (DS) and plaque volume (PV) were correlated with the fractional flow reserve (FFR) values measured with a commercially-available pressure guide-wire. FFR <0.75 was considered significant. Using FFR, only 9/41 lesions appeared haemodynamically significant (FFR <0.75). When compared to lesions with an FFR >0.75, these lesions had higher CSS (65.3+/-9.4% vs. 44.7+/-10.6%, p=0.0001), higher DS (48+/-5.7% vs. 32.5+/-9.9%, p=0.0001), and higher PV (41.6+/-7.6% vs. 29.4+/-6.7%, p=0.0005), as measured by 3-D QCA. Regression analysis showed significant correlations between FFR and CSS (r=-0.481, p=0.001) and PV (r=-0.443, p=0.004), and a modest correlation between FFR and DS (r=-0,320, p=0.041). Compared with FFR, a CSS of 57% had the highest sensitivity and specificity (88.9% and 87.5%, respectively) for determining significant IL. Multivariate analysis showed 3-D-determined CSS to better predict FFR compared to the other measured variables (p=0.012). Parameters obtained by 3-D QCA showed a significant correlation with FFR values. A cross-sectional stenosis >57% obtained by 3-D QCA has a high degree of sensitivity and specificity to detect a haemodynamically significant intermediate coronary stenosis.

Assessment of the contractile reserve in patients with intermediate coronary lesions: a strain rate imaging study validated by invasive myocardial fractional flow reserve

The present study aims to compare the change of left ventricular deformation during dobutamine stress echocardiography (DSE) with the reference standard of invasive myocardial fractional flow reserve (FFR) to assess the haemodynamic significance of intermediate coronary lesions. In 30 patients with an intermediate coronary artery stenosis in one epicardial coronary artery, FFR measurements were performed during coronary catheterization. In case of an FFR < 0.75 after intracoronary adenosine administration, the stenosis was considered significant, indicating ischaemia. In addition, during DSE, peak systolic strain rate and systolic strain of the region of interest (supplied by the stenotic vessel) and of a non-ischaemic remote region were assessed at baseline and at peak stress. Thirteen patients had an FFR >or= 0.75, indicating normal flow reserve (non-ischaemic group). The remaining 17 patients with an FFR < 0.75 comprised the ischaemic group. At baseline DSE, mean values of strain rate (-1.2 +/- 0.3 s(-1)) and strain (-17 +/- 8%) were not significantly different between both groups. In the ischaemic group, in the target region, strain at peak stress decreased to - 10 +/- 8%, whereas strain rate remained unchanged. In contrast, in the non-ischaemic group, strain at peak stress remained unchanged (-18 +/- 7%), whereas strain rate increased to - 2.5 +/- 1.1 s(-1). The receiver operating characteristic curve analysis revealed the change in strain rate as the best parameter to detect ischaemia, with a sensitivity of 89% and a specificity of 86%. In the remote region, in both groups, strain rate (-1.4 +/- 0.4 s(-1)) and strain values (-20 +/- 7%) were not significantly different at baseline, and strain rate doubled and strain remained unchanged at DSE peak stress. Non-invasive evaluation of regional deformation, using strain rate imaging during DSE, predicted the relevance of intermediate coronary stenosis. In this context, strain rate is superior to strain measurements for the quantification of the contractile reserve.

786-2 Coronary Flow Reserve vs Transleslonal Velocity Gradient by Doppler Guidewire in Assessing Intermediate Coronary Stenoses

Intracoronary Doppler guidewire measures of coronary flow reserve (CFR) and translesional velocity gradients (TVG) have been used to determine the physiologic significance of intermediate coronary lesions (40–70%). In many patients with intermediate stenoses CFR and TVG values are discordant, raising the possibility that CFR is diminished due to microvascular rather than epicardial disease. In 13 patients with an intermediate coronary lesion, we used an intracoronary Doppler guidewire to record baseline coronaryflowvelocity proximal and distal to each lesion, thus defining TVG. Peak hyperemic velocity was then recorded distally after an intracoronary bolus of adenosine to obtain CFR. All patients had decreased CFR (mean = 1.4 ± 0.3; normal ≥2.0) but trivial TVG (mean = 1.3 ± 0.3; normal &lt;1.7). Each patient had a reversible perfusion defect on stress SPECT 201 TI imaging and subsequently underwent PTCA. These patients were asked to return at 6 months for a repeat stress SPECT201 TI test. Two patients had restenosis prior to repeat stress testing. The remaining 11 patients had their baseline and 6 month post-PTCA scans analyzed. Region of Interest201 TI Ouantitation (counts as % of normal) Pre-PTCA Stress 77 ± 2.5 Post-PTCA Stress 89 ± 3.0 * Delay 93 ± 3.0 * Delay 93 ± 4.0 P(ANOVA) &lt; 0.0001 * p &lt; 0.05 vs Pre-PTCA Stress All 11 patients demonstrated qualitative normalization of SPECT 201 TI scans at 6 month follow-up. Ouantitative polar mapping and region of interest analysis confirmed the improvement in perfusion. Therefore, blunted CFR was related to a physiologically significant intermediate stenosis rather than a microvascular cause. It appears that CFR is a more reliable indicator of lesion significance than TVG.