Anatomical and physiologic assessments in patients with small coronary artery disease: final results of the Physiologic and Anatomical Evaluation Prior to and After Stent Implantation in Small Coronary Vessels (PHANTOM) trial

Fractional flow reserve and non-hyperemic indices: Essential tools for percutaneous coronary interventions

Hemodynamical evaluation of a coronary artery lesion is an important diagnostic step to assess its functional impact. Fractional flow reserve (FFR) received a class IA recommendation from the European Society of Cardiology for the assessment of angiographically moderate stenosis. FFR evaluation of coronary artery disease offers improvement of the therapeutic strategy, deferring unnecessary procedures for lesions with a FFR > 0.8, improving patients' management and clinical outcome. Post intervention, an optimal FFR > 0.9 post stenting should be reached and > 0.8 post drug eluting balloons. Non-hyperemic pressure ratio measurements have been validated in previous studies with a common threshold of 0.89. They might overestimate the hemodynamic significance of some lesions but remain useful whenever hyperemic agents are contraindicated. FFR remains the gold standard reference for invasive assessment of ischemia. We illustrate this review with two cases introducing the possibility to estimate also non-invasively FFR from reconstructed 3-D angiograms by quantitative flow ratio. We conclude introducing a hybrid approach to intermediate lesions (DFR 0.85-0.95) potentially maximizing clinical decision from all measurements.

Value of Delta Fractional Flow Reserve (ΔFFR) For Predicting Coronary Ischemic Lesions

Background:

The decrease in fractional flow reserve (FFR) after adenosine administration from baseline FFR value (termed as ΔFFR) may reflect the compensatory capacity of the microvascular circulation and thus may predict significant coronary stenotic lesions. We aimed to investigate whether baseline FFR and ΔFFR can help identify the coronary ischemic lesion and its severity.

Materials and Methods:

This cross-sectional study was performed on 154 consecutive patients (Mean age 62.42 ± 9.36 years) that underwent coronary angiography and with definitive intermediate coronary lesions at any of the coronary vessels. FFR was calculated by dividing the mean distal intracoronary pressure by the mean arterial pressure. ΔFFR was also defined as the difference between baseline FFR and hyperemic FFR (considering FFR<0.75 as the criteria for ischemia).

Results:

The area under receiver-operating characteristic curve for baseline FFR was found as 0.933, and for ΔFFR was 0.946 indicated high values of both indices for predicting ischemic lesions. The best cut-off point for baseline FFR and ΔFFR for discriminating ischemic lesions from the normal condition was 89.5 (yielding a sensitivity of 92.2% and a specificity of 68.0%) and 9.5 (yielding a sensitivity of 96.0% and a specificity of 85.3%), respectively.

Conclusion:

Our study could successfully demonstrate the high value of both baseline FFR and ΔFFR for predicting coronary ischemic lesions with the cut-off values of <89.5 and >9.5, respectively.

Prognostic value of pericoronary inflammation and unsupervised machine-learning-defined phenotypic clustering of CT angiographic findings

BACKGROUND

Pericoronary adipose tissue attenuation expressed by fat attenuation index (FAI) on coronary CT angiography (CCTA) reflects pericoronary inflammation and is associated with cardiac mortality.

OBJECTIVE

The aim of this study was to define the sub-phenotypes of coronary CCTA-defined plaque and whole vessel quantification by unsupervised machine learning (ML) and its prognostic impact when combined with pericoronary inflammation.

METHODS

A total of 220 left anterior descending arteries (LAD) with intermediate stenosis who underwent fractional flow reserve (FFR) measurement and CCTA were studied. After removal of outcome and FAI data, the phenotype heterogeneity of CCTA-defined plaque and whole vessel quantification was investigated by unsupervised hierarchical clustering analysis based on Ward's method. Detailed features of CCTA findings were assessed according to the clusters (CS1 and CS2). Major adverse cardiac events (MACE)-free survivals were assessed according to the stratifications by FAI and the clusters.

RESULTS

Compared with CS2 (n = 119), CS1 (n = 101) were characterized by greater vessel size, increased plaque volume, and high-risk plaque features. FAI was significantly higher in CS1. ROC analyses revealed that best cut-off value of FAI to predict MACE was -73.1. Kaplan-Meier analysis revealed that lesions with FAI ≥ -73.1 had a significantly higher risk of MACE. Multivariate Cox proportional hazards regression analysis revealed that age, FAI ≥ -73.1, and the clusters were independent predictors of MACE.

CONCLUSION

Unsupervised hierarchical clustering analysis revealed two distinct CCTA-defined subgroups and discriminated by high-risk plaque features and increased FAI. The risk of MACE differs significantly according to the increased FAI and ML-defined clusters.

The assessment of intermediate coronary lesions using intracoronary imaging

Intermediate coronary artery stenosis, defined as visual angiographic stenosis severity of between 30-70%, is present in up to one quarter of patients undergoing coronary angiography. Patients with this particular lesion subset represent a distinct clinical challenge, with operators often uncertain on the need for revascularization. Although international guidelines appropriately recommend physiological pressure-based assessment of these lesions utilizing either fractional flow reserve (FFR) or quantitative flow ratio (QFR), there are specific clinical scenarios and lesion subsets where the use of such indices may not be reliable. Intravascular imaging, mainly utilizing intravascular ultrasound (IVUS) and optical coherence tomography (OCT) represents an alternate and at times complementary diagnostic modality for the evaluation of intermediate coronary stenoses. Studies have attempted to validate these specific imaging measures with physiological markers of lesion-specific ischaemia with varied results. Intravascular imaging however also provides additional benefits that include portrayal of plaque morphology, guidance on stent implantation and sizing and may portend improved clinical outcomes. Looking forward, research in computational fluid dynamics now seeks to integrate both lesion-based physiology and anatomical assessment using intravascular imaging. This review will discuss the rationale and indications for the use of intravascular imaging assessment of intermediate lesions, while highlighting the current limitations and benefits to this approach.

Small vessel coronary artery disease: How small can we go with myocardial revascularization?

The issue of small coronary artery atherosclerosis represents an intriguing aspect of coronary artery disease, which is related with higher rates of peri- and post-procedural complications and impaired long-term outcome. This problem is further complicated by the unclear definition of small coronary vessel. Recent randomized controlled trials have provided new data on possible novel interventional treatment of small coronary vessels with drug-coated balloons instead of traditional new-generation drug-eluting stent implantation. Also, the conservative management represents a therapeutic option in light of the results of the recent ISCHEMIA trial. The current article provides an overview of the most appropriate definition, interventional management, and prognosis of small coronary artery atherosclerosis.

Assessment of intermediate coronary lesions by fractional flow reserve and quantitative flow ratio in patients with small-vessel disease

BACKGROUND

Quantitative flow ratio (QFR) has recently been introduced as a novel, less-invasive, adenosine-free measure for functional coronary lesion assessment. Whether reference vessel dimensions affect functional lesion assessment is uncertain.

METHODS

A total of 436 patients with 516 interrogated coronary vessels by means of FFR were included in the study. Patients were dichotomized according to the median reference vessel diameter (group 1: ≤2.8 mm and group 2: >2.8 mm). QFR analyses were performed offline at the institution's core laboratories.

RESULTS

Reference vessel diameter was 2.5 [2.3-2.7] mm in group 1 and 3.3 [3.0-3.6] mm in group 2. Diameter stenosis (41.4 [36.4-47.6] % vs. 41.4 [36.4-45.7] %, p = .20) did not differ among groups. Median FFR values were lower in group 1 (0.87 [0.81-0.92]) as compared with group 2 (0.89 [0.84-0.93], p = .001). Consistently, QFR values were lower in group 1 (0.88 [0.82-0.92]) than in group 2 (0.91 [0.85-0.94], p = .001). The proportions of functionally significant coronary lesions as defined by FFR ≤0.80 were 24.1% and 14.2% in groups 1 and 2 (p = .005), and as defined by cQFR ≤0.80 20.4% and 11.8% (p = 0.009), respectively. In ROC analysis for an FFR ≤.80, the AUC was 0.89 (95% CI 0.85-0.93, p < .001) in group 1 and 0.81 (95% CI 0.76-0.86, p < .001) in group 2.

CONCLUSIONS

These results suggest that QFR measurements are accurate irrespective of the reference vessel diameter. Future studies are needed to elucidate the higher percentage of functionally significant lesions observed in small vessels despite a similar angiographic lesion severity.

Intravascular Ultrasound for Guidance and Optimization of Percutaneous Coronary Intervention

Percutaneous coronary intervention (PCI) remains the mainstay management of symptomatic obstructive stable coronary artery disease (despite optimal medical treatment) and acute coronary syndrome. Intravascular ultrasound (IVUS) has emerged as an adjunct to angiography, permitting better assessment of the coronary lesion and stent apposition. Data from multiple studies have demonstrated improved clinical and procedural outcomes with IVUS-guided PCI. This review discusses the use of IVUS, with emphasis on technique, parameters, and applications during coronary interventions. In addition, the clinical outcomes data are highlighted with IVUS compared with conventional angiography-guided PCI.

Impact of plaque characteristics on the degree of functional stenosis

Coronary CT angiography (CCTA) is mainly regarded as a gatekeeper for invasive coronary angiography, in face of its widely recognized value to noninvasively rule out significant coronary stenosis. Nevertheless, it is also increasingly recognized that this noninvasive modality can depict several atherosclerotic plaque features and quantify total coronary plaque burden. This opens a new field for cardiac CT, since these atherosclerotic features beyond stenosis severity have been correlated with the degree of functional significance, and are the focus of the present manuscript. Although recently acknowledged and documented in CCTA studies, the relation between plaque burden and functional significance has been previously described using several intracoronary imaging modalities, which are also reviewed in the manuscript, to help put in perspective the relation between anatomy and function in coronary artery disease.

Modified residual SYNTAX score and clinical outcomes in patients with multivessel disease undergoing percutaneous coronary intervention

AIMS

We sought to determine a reasonable level of revascularisation using the modified residual SYNergy between percutaneous coronary intervention (PCI) with TAXus and cardiac surgery (SYNTAX) score in patients undergoing PCI.

METHODS AND RESULTS

In 3,460 patients with multivessel disease receiving drug-eluting stents, residual SYNTAX score (rSS) was calculated for lesions with ≥50% diameter stenosis in vessels ≥1.5 mm after PCI. The "modified" rSS (mrSS) was determined by counting lesions with ≥70% diameter stenosis in vessels ≥2.5 mm only. Patients were categorised into the complete revascularisation (CR) group (rSS=0), the incomplete revascularisation (ICR) group (mrSS >0), or the reasonable ICR (R-ICR) group (rSS >0, but mrSS=0). After propensity matching, the R-ICR group (n=1,129) had a comparable risk of all-cause death (HR 0.80, 95% CI: 0.56-1.15, p=0.24) and a composite of all-cause death, myocardial infarction (MI), or repeat revascularisation (HR 0.91, 95% CI: 0.74-1.14, p=0.41) compared with the CR group (n=637) at three years. In separate propensity matching analyses, patients with R-ICR (n=1,280) had a lower risk of all-cause death (HR 0.73, 95% CI: 0.55-0.97, p=0.03) and a composite of all-cause death, MI, or repeat revascularisation (HR 0.68, 95% CI: 0.57-0.82, p<0.001) than those with ICR (n=837) at three years.

CONCLUSIONS

Complete revascularisation of lesions with ≥70% diameter stenosis in vessels ≥2.5 mm is better than ICR, and is a reasonable goal for patients with multivessel disease.

A systematic review of imaging anatomy in predicting functional significance of coronary stenoses determined by fractional flow reserve

Fractional flow reserve (FFR) is the current gold standard to assess the physiological significance of coronary stenoses. With the development of coronary imaging techniques, several anatomic parameters have been investigated in vivo and their associations with FFR have been studied. The aim of this review is to summarize the accuracy of anatomic parameters derived by the present coronary imaging techniques including invasive coronary angiography, coronary computed tomography angiography, intravascular ultrasound and optical coherence tomography, in predicting a significant FFR. The impact of patient characteristics, lesion locations, variability of FFR and imaging resolution on the predictive ability are discussed.

Usefulness of combined intravascular ultrasound parameters to predict functional significance of coronary artery stenosis and determinants of mismatch

AIMS

Efficacy of combined intravascular ultrasound (IVUS) parameters in functional significance prediction and discrepancy between IVUS and fractional flow reserve (FFR) have not been well defined. This study therefore aimed to: 1) evaluate the diagnostic accuracy of combined IVUS parameters, namely minimal lumen area (MLA) and percent plaque burden (%PB), in functional significance prediction of coronary artery stenosis; and 2) define factors that affect the relation between FFR value and IVUS parameters.

METHODS AND RESULTS

At 11 international centres, IVUS and FFR measurements were concurrently performed in 945 major epicardial coronary artery lesions (886 patients). Functional significance was defined as FFR ≤0.8. MLA and FFR correlated weakly (r=0.289, p<0.001). Diagnostic accuracy of MLA ≤4.0 mm2, %PB >70% and their combination were 50%, 47% and 51%, respectively, with similar area under the curve (AUC) of 0.561, 0.511 and 0.516, respectively. The best cut-off values (BCV) were MLA ≤3.0 mm2 and %PB >75%, with accuracy of 60% for MLA, 50% for %PB and 56% for their combination, and AUC of 0.618, 0.511 and 0.533, respectively. MLA BCV ≤3.0 mm2 had higher predictive power than %PB BCV >75% or their combination. Independent predictors of functional significance were male gender (odds ratio 1.76 [95% confidence interval: 1.19-2.62]), left ventricular ejection fraction (LVEF, 0.98 [0.96-0.99]), LAD lesion (2.52 [1.73-3.67]), reference vessel diameter (0.60 [0.41-0.86]), lesion length (1.04 [1.02-1.06]) and MLA (0.79 [0.69-0.92]). False negative lesion incidence was 24.4% in association with race (for Asians, 0.391 [0.219-0.698]), LAD lesion (2.677 [1.709-4.191]) and LVEF (0.977 [0.957-0.997]). False positive lesion incidence was 17.0% in association with non-LAD lesion (2.444 [1.620-3.686]).

CONCLUSIONS

Combined IVUS parameters did not improve the accuracy of functional significance prediction. Discrepancy between IVUS and FFR, which was not rare, should be taken into account in clinical decision making.

Comprehensive assessment of coronary fractional flow reserve

Fractional flow reserve (FFR) is considered nowadays as the gold standard for invasive assessment of physiologic stenosis significance and an indispensable tool for decision-making in coronary revascularization. Robust studies have shown that FFR is more effective in accurately identifying which lesions should be stented, and revascularization guided by FFR improves the outcome of coronary artery disease in patients. Therefore, FFR has been upgraded to a class A recommendation in current guidelines when the ischemic potential for specific target lesions is controversial. This article reviews the laboratory practice, functional evaluation of FFR as a gold standard and its emerging clinical application. In addition, novel noninvasive technologies of FFR measurement are discussed in depth.

Meta-analysis of deferral versus performance of coronary intervention based on coronary pressure-derived fractional flow reserve

Fractional flow reserve (FFR) has been proposed as the gold standard to assess functional severity of coronary artery stenosis and to stratify which lesions should be subjected to intervention (percutaneous coronary intervention [PCI]). A systematic review was performed in MEDLINE and EMBASE including studies indexed until November 2013 that used FFR for deferral or performance of PCI. Outcomes of interest were death, acute myocardial infarction (AMI), and new revascularization (RV). Nineteen studies were included, totaling 3,097 patients (3,796 lesions). Mean follow-up was 21.2 months. In indirect comparisons, FFR-PCI and FFR-defer groups had similar death (2.2% vs 2.0%, respectively, p = 0.86) and AMI rates (1.9% vs 1.9%, respectively, p = 1.00). RV rates were higher in the FFR-PCI group (14.0% vs 4.4%, p = 0.002). Direct comparisons (2-arm trials) also showed no differences in death (odds ratio [OR] 1.86 [95% CI 0.81 to 4.27], I(2) = 11.5, p = 0.14) and AMI rates (OR 0.75 [95% CI 0.21 to 2.69], I(2) = 47.1, p = 0.66); RV rates were again higher in the FFR-PCI (OR 3.10 [95% CI 1.25 to 7.70], I(2) = 72.2, p = 0.015). Meta-regression suggests influence of male gender on RV rates (β = 0.058, p = 0.026). In conclusion, deferral of PCI based on FFR is a safe strategy. Considerable heterogeneity was observed, however.

Relationship between intravascular ultrasound parameters and fractional flow reserve in intermediate coronary artery stenosis of left anterior descending artery: intravascular ultrasound volumetric analysis

OBJECTIVES

The objective of this study was to assess the relationship between intravascular ultrasound (IVUS) parameters, including volumetric analysis, and fractional flow reserve (FFR).

BACKGROUND

Although it is known that coronary atherosclerosis burden measured by IVUS volumetric analysis is related with clinical outcomes, its relationship with functional significance remains unknown.

METHODS

Both IVUS and FFR were performed in 206 cases of intermediate stenosis of the left anterior descending artery (LAD). Myocardial ischemia was assessed by FFR and maximal hyperemia was induced by continuous intracoronary adenosine infusion. FFR < 0.80 was considered as significant inducible myocardial ischemia. We performed standard IVUS parameter measurements and volumetric analyses. IVUS parameter comparison was performed in the presence (n = 90) or absence (n =116) of significant myocardial ischemia.

RESULTS

Lesions with minimal lumen area (MLA) ≥ 4.0 mm2 had FFR ≥ 0.80 in 91.4% of cases, while 50.9% of lesions with MLA < 4.0 mm2 had FFR < 0.80. The independent predictors of FFR < 0.80 were IVUS lesion length (odds ratio [OR]: 1.1, 95% confidence interval [CI] = 1.06–1.18, P < 0.001) and MLA significance according to the lesion location (OR: 7.01, 95% CI = 3.09–15.92, P = 0.001). FFR correlated with plaque volume (r = −0.345, P < 0.001) and percent atheroma volume (PAV) (r = −0.398, P < 0.001). Lesions with significant ischemia (FFR < 0.80) as compared to those with FFR > 0.80 were associated with larger plaque volume (181.8 ± 82.3 vs. 125.9 ± 77.9 mm3, P < 0.001) and PAV (58.9 ± 5.6 vs. 53.8 ± 7.9%, P < 0.001).

CONCLUSIONS

IVUS parameters representing severity and extent of atheromatous plaque correlated with functional significance in LAD lesions with intermediate stenosis.

Outcomes associated with fractional flow-guided revascularization: a meta-analysis

BACKGROUND

Deferral of revascularization for abnormal but nonischemic lesions is usually recommended; however, the long-term outcome of this approach is not well known.

HYPOTHESIS

Deferral of nonischemic lesions will be associated with a low frequency of adverse events.

METHODS

A PubMed search of the MEDLINE database identified studies that reported clinical outcomes among patients who had fractional flow reserve-guided revascularization. We further categorized studies into 2 subgroups: left main and non-left main coronary artery lesions. Baseline demographics and clinical outcome data were extracted by 3 independent reviewers. Fixed and random effects summary risk ratios were constructed using Mantel-Haenszel and DerSimonian-Laird models, respectively. The primary outcome was the composite of death, myocardial infarction, and revascularization.

RESULTS

From 741 potential studies, 17 were included in the meta-analysis (n = 2975 participants), 8 in the left main subgroup (n = 595) and 9 studies (n = 2380) in non-left main subgroup. In the left main subgroup, the incidence of the composite outcome was 15.3% in the no-ischemia/deferral group vs 14.3% in the ischemia/revascularization group (risk ratio [RR] = 1.13, 95% confidence interval [CI]: 0.76-1.68, P = 0.54, I(2) = 3.7%). In the non-left main subgroup, the incidence of the composite outcome was 9.2% in the no-ischemia/deferral group vs 18.8% in the ischemia/revascularization group (RR = 0.42, 95% CI: 0.34-0.52, P < 0.0001, I(2) = 20.7%).

CONCLUSIONS

Patients with left main coronary disease had a relatively high incidence of adverse cardiovascular events, which was similar in both the deferral and revascularization groups. In patients with non-left main disease, ischemia was associated with worse outcomes despite revascularization.

Fractional flow reserve: an updated review

Revascularization of ischemia-producing coronary lesions is widely used in the management of coronary artery disease. However, some coronary lesions appear significant on the conventional angiogram when they are truly non-flow limiting. For this reason, it is becoming increasingly important to determine the coronary physiology. Fractional flow reserve (FFR) has emerged as a useful tool to determine the lesions that require revascularization. Measurement of FFR during invasive coronary angiography now has a class IA indication from the European Society of Cardiology for identifying hemodynamically significant coronary lesions when noninvasive evidence of myocardial ischemia is unavailable. Current data on FFR can be broadly classified into studies that compare the diagnostic accuracy of FFR measurement compared with other noninvasive modalities and studies that test treatment strategies of patients with intermediate coronary stenoses using a threshold value for FFR and that have clinical outcomes as endpoints. In this review, we will discuss the concept of FFR, current evidence supporting its usage, and future perspectives.

Impact of Intravascular Ultrasound in Clinical Practice

Intravascular ultrasound (IVUS) has expanded our understanding of atherosclerotic plaque morphology, and provides an opportunity to guide cardiovascular interventions and evaluate results. Use of this technique requires understanding of ultrasound physics, catheter differences, skills in vessel, plaque and stent quantification and knowledge of artifacts and various physiologic and pathologic findings. Optimal cardiovascular interventions should result in absence of inflow or outflow obstruction, precise geographic landing, while attaining the largest feasible luminal gain without plaque protrusion, vessel dissection or perforation and, if deployed, with complete stent expansion and apposition to the vessel wall. IVUS is safe, cost efficient and effectively optimises cardiovascular interventions. In addition, IVUS improves outcomes when used to guide coronary interventions using bare metal stents (BMS) and drug eluting stents (DES). The role of IVUS in endovascular therapy is rapidly expanding. This review will focus on the impact of IVUS in clinical practice.

Optical coherence tomography criteria for defining functional severity of intermediate lesions: a comparative study with FFR

Fractional flow reserve (FFR) is the gold standard in the assessment of severity of the coronary stenosis. The aim of the study was to compare optical coherence tomography (OCT) obtained intermediate coronary lesions lumen areas measurements with FFR assessments, with the goal to develop an OCT threshold to identify significant coronary stenosis. 48 patients (mean age 65 ± 10 years) was enrolled for the study. Within this population, 71 intermediate coronary lesions were investigated using both FFR and OCT. High dose bolus of Adenosine (120 μg) was used to obtain coronary hyperemia. OCT imaging was performed using non-occlusive technique to assess minimal lumen area (MLA) and diameter. The OCT cut-off value that showed the best correlation with the FFR cut-off of 0.80 was the MLA less than 2.05 mm2 (accuracy 87%, sensitivity 75%, specificity 90%, p < 0.001). The study did not disclose any relationship between FFR value and the lesion length. Vessel size influenced the OCT cut-off values, with greater values being found in presence of arteries with a reference diameter greater than 3.0 mm. OCT derived minimal lumen area might be complementary to FFR measurement in identifying ischemia related lesions. Further studies are warranted to assess threshold values in relation to vessel size and location.

Percutaneous revascularization strategies in small-vessel disease

Percutaneous coronary intervention (PCI) of small coronary vessels represents a real challenge for myocardial revascularization because of the high risk of stent-restenosis and increased risk of adverse clinical events. Moreover, small coronary arteries supply small myocardial territories therefore questioning the clinical significance of small-vessel stenoses. The definition of small-vessel disease and PCI-strategies used are very heterogeneous across studies. The present review will focus on percutaneous coronary revascularization in patients with small vessel coronary artery disease.

One-year outcome of small-vessel disease treated with sirolimus-eluting stents: a subgroup analysis of the e-SELECT registry

OBJECTIVES

To investigate the characteristics and one-year outcomes following sirolimus-eluting CYPHER Select Plus stent (SES) implantation in small (SmVD) and non-small vessel disease (NSmVD) in the international e-SELECT registry.

BACKGROUND

Large-scale registry data are lacking on DES outcomes in SmVD treatment.

METHODS

There were 4,700 SmVD (at least one vessel with estimated reference vessel diameter [RVD] < 2.5 mm, excluding 283 patients with unknown RVD vessels) and 10,139 NSmVD only patients.

RESULTS

The SmVD population was older, with more women, diabetics, and vessels treated, higher mean Charlson Comorbidity Index score (CCI), shorter lesions, and less STEMI presentation. The 1-year stent thrombosis (ST) rate (primary end-point), was significantly higher (1.3% vs. 0.7%) in SmVD versus NSmVD, mainly driven by early events. One-year major adverse cardiac event (MACE), myocardial infarction (MI), and clinically indicated target-lesion revascularization (TLR) rates were significantly higher in SmVD although death and major bleeding rates were similar in both groups. Complication rates were similar between pure (3,188 patients; only RVD < 2.5 mm) and mixed (1,795 patients; some RVD < 2.5 mm or unknown RVD) SmVD. Multivariate predictors for 1-year MACE in SmVD included saphenous vein graft or bifurcation lesions, major bleeding, any antiplatelet therapy discontinuation within 1 month, age, number of stents implanted, CCI, acute coronary syndrome, and insulin-dependent diabetes mellitus.

CONCLUSION

SES implantation for SmVD occurs more frequently in women, diabetics, and those with multivessel disease and comorbidities. One-year ST, MACE, MI, and clinically indicated TLR rates are higher, although low overall, in SmVD or mixed SmVD patients while death rates are similar to NSmVD.

Morphometric assessment of coronary stenosis relevance with optical coherence tomography: a comparison with fractional flow reserve and intravascular ultrasound

OBJECTIVES

The study sought to assess the diagnostic efficiency of optical coherence tomography (OCT) in identifying hemodynamically severe coronary stenoses as determined by fractional flow reserve (FFR). Concomitant OCT and intravascular ultrasound (IVUS) area measurements were performed in a subgroup of patients to compare the diagnostic efficiency of both techniques.

BACKGROUND

The value of OCT to determine stenosis severity remains unsettled.

METHODS

Sixty-one stenoses with intermediate angiographic severity were studied in 56 patients. Stenoses were labeled as severe if FFR ≤0.80. OCT interrogation was performed in all cases, with concomitant IVUS imaging in 47 cases.

RESULTS

Angiographic stenosis severity was 50.9 ± 8% diameter stenosis with 1.28 ± 0.3 mm minimal lumen diameter. FFR was ≤0.80 in 28 (45.9%) stenoses. An overall moderate diagnostic efficiency of OCT was found (area under the curve [AUC]: 0.74; 95% confidence interval [CI]: 0.61 to 0.84), with sensitivity/specificity of 82%/63% associated with an optimal cutoff value of 1.95 mm(2). Comparison of the results in patients with simultaneous IVUS and OCT imaging revealed no significant differences in the diagnostic efficiency of OCT (AUC: 0.70; 95% CI: 0.55 to 0.83) and IVUS (AUC. 0.63; 95% CI: 0.47 to 0.77; p = 0.19). Sensitivity/specificity for IVUS was 67%/65% for an optimal cutoff value of 2.36 mm(2). In the subgroup of small vessels (reference diameter <3 mm) OCT showed a significantly better diagnostic efficiency (AUC: 0.77; 95% CI: 0.60 to 0.89) than IVUS (AUC: 0.63; 95% CI: 0.46 to 0.78) to identify functionally significant stenoses (p = 0.04).

CONCLUSIONS

OCT has a moderate diagnostic efficiency in identifying hemodynamically severe coronary stenoses. Although OCT seems slightly superior to IVUS for this purpose (particularly in vessels <3 mm), its low specificity precludes its use as a substitute of FFR for functional stenosis assessment.

Long-term clinical outcome after fractional flow reserve-guided percutaneous coronary revascularization in patients with small-vessel disease

BACKGROUND

Small coronary vessels supply small myocardial territories. The clinical significance of small-vessel stenoses is therefore questionable. Moreover, percutaneous coronary intervention (PCI) of nonfunctionally significant lesions does not improve clinical outcome and might be associated with potential procedural or stent related risks. The aim of this study was to assess the clinical outcome of fractional flow reserve (FFR)-guided PCI in the treatment of small coronary vessel lesions as compared with an angio-guided PCI.

METHODS AND RESULTS

From January 2004 to December 2008, all patients treated with PCI for stable or unstable angina in small native coronary vessels (reference vessel diameter and stent size <3 mm) were retrospectively analyzed. Patients were divided into angio-guided and an FFR-guided PCI groups. A total of 717 patients were enrolled (495 angio-guided, 222 FFR-guided). End points were death, nonfatal myocardial infarction (MI), combined death or nonfatal MI, target vessel revascularization (TVR), and procedure costs. Major adverse cardiac events (MACE) were defined as death, nonfatal MI, and TVR. Clinical follow-up was obtained in 97.5% (median follow-up: 3.3 [from 0.01-5] years) of the patients. Seventy-eight patients (35%) had a significant FFR (<0.80) and underwent PCI. Using a propensity score adjusted Cox analysis, patients treated with FFR-guided PCI had significantly lower combined death or nonfatal MI (hazard ratio [HR], 0.413; 95% confidence interval [CI], 0.227-0.750; P=0.004), nonfatal MI (HR, 0.063; 95% CI, 0.009-0.462; P=0.007), TVR (HR, 0.517; 95% CI, 0.323-0.826; P=0.006), and MACE (HR, 0.458; 95% CI, 0.310-0.679; P<0.001). No difference was observed in mortality alone (HR, 0.684; 95% CI, 0.355-1.316; P=0.255). Procedure costs were also reduced in the FFR guided strategy (3253±102 Euros versus 4714±37 Euros, P<0.0001).

CONCLUSIONS

FFR-guided PCI of small coronary arteries is safe and results in better clinical outcomes when compared with an angio-guided PCI.

Wingspan stents for the treatment of symptomatic atherosclerotic stenosis in small intracranial vessels: safety and efficacy evaluation

BACKGROUND AND PURPOSE

Until now, endovascular treatment of symptomatic atherosclerotic stenosis in small intracranial arteries (≤2.5 mm) was limited. We evaluated the safety and efficacy of the treatment by using Wingspan stents in arteries of this caliber.

MATERIALS AND METHODS

From March 2007 to July 2010, 53 symptomatic intracranial stenoses with narrowing of at least 50% in 53 patients were treated by using Wingspan stents. Clinical manifestations and imaging features were recorded.

RESULTS

The technical success rate was 98.1%. There were no serious complications, with the exception of 1 patient who experienced a small cerebral hemorrhage caused by perforation of microwire. Thirty-nine patients (74%) were available for follow-up imaging with DSA. ISR was documented in 13 of these patients, including 2 patients with symptomatic ISR. The median length of the vascular lesions was 5.39 mm, and patients whose vascular lesions were longer than 5.39 mm had a much higher incidence of ISR than patients whose vascular lesions were shorter than 5.39 mm (53% versus 15%, respectively). The median ratio of the reference artery diameter to the stent diameter was 0.78, and patients whose ratio was smaller than 0.78 had a much higher incidence of ISR than patients whose ratio was larger than 0.78 (53% versus 15%, respectively).

CONCLUSIONS

In our series, percutaneous transluminal angioplasty and stent placement of small intracranial arteries by using Wingspan stents was safe. The ISR rate was relatively high; most patients having ISR were asymptomatic. Further follow-up is needed to assess the long-term efficacy of this procedure.

Utilization of frequency domain optical coherence tomography and fractional flow reserve to assess intermediate coronary artery stenoses: conciliating anatomic and physiologic information

Fractional flow reserve (FFR) and intravascular imaging respectively provide hemodynamic and anatomical assessments of angiographic intermediate stenoses. Frequency domain optical coherence tomography (FD-OCT) is a promising high-resolution imaging modality, but its clinical use in determining severity of coronary disease has yet to be determined. There, we set out to determine the role of FD-OCT to complement FFR in the evaluation of intermediate coronary artery stenoses. FD-OCT was planned in 176 consecutive interventional procedures at our institution to delineate the proper use of FD-OCT in clinical practice. The decision to use other invasive assessments was at the discretion of the operator. This report describes an early series of the 14 patients who underwent FFR of 18 target stenoses in addition to FD-OCT. FD-OCT was successfully performed without complications in all cases. Fractional flow reserve was <0.80 in four patients, with minimal lumen areas and reference vessel diameters ranging from 1.03 to 3.47 mm(2) and 2.60 to 2.94 mm by FD-OCT, respectively. FD-OCT was important to rule out plaque rupture, erosion and thrombosis and to help guide decision to defer PCI in six patients with acute coronary syndrome and FFR > 0.80. FD-OCT was also valuable to guide PCI strategy in tandem lesions with an FFR < 0.80. This initial experience with FD-OCT suggests a potential complementary role of physiological and anatomical assessment to guide decision making in complex clinical scenarios. Future investigations are warranted to validate these findings and define the role of FD-OCT in assessing intermediate lesions.

New set of intravascular ultrasound-derived anatomic criteria for defining functionally significant stenoses in small coronary arteries (results from Intravascular Ultrasound Diagnostic Evaluation of Atherosclerosis in Singapore [IDEAS] study)

We sought to determine the intravascular ultrasound-derived anatomic criteria for functionally significant lesions in small coronary arteries with a reference segment diameter <3 mm. A fractional flow reserve (FFR) of <0.75, as determined by pressure wire using high-dose (100 to 150 microg) intracoronary adenosine, was used as the reference standard for functional significance. For the 94 patients/lesions involved in the present study, the average reference vessel diameter was 2.72 mm. The FFR was <0.75 in 38 patients (40.4%) and > or =0.75 in 56 patients (59.6%). Logistic regression analysis identified the minimal lumen area, plaque burden, and lesion length as the 3 most important determinants of the FFR. Using classification and regression tree analysis, the best cutoff values for these determinants to discriminate a FFR of <0.75 versus > or =0.75 were a minimal lumen area of < or =2.0 mm(2) (sensitivity 82.35%, specificity 80.77%), plaque burden of > or =80% (sensitivity 87.9%, specificity 78.9%), and lesion length of > or =20 mm (sensitivity 63.6%, specificity 78.9%). A significant increase was found in the area under the receiver operating characteristic curve of the combined parameters (minimal lumen area plus plaque burden plus lesion length) compared to the plaque burden (p = 0.014) and other individual parameters (p <0.001). In conclusion, we found that intravascular ultrasound-derived anatomic criteria are able to predict the functional significance of intermediate lesions in small coronary arteries. A minimal lumen area of < or =2.0 mm(2), plaque burden of > or =80%, and lesion length of > or =20 mm predicted a FFR of <0.75 with good sensitivity and specificity.

The reliability of fractional flow reserve measurement in patients with diabetes mellitus

BACKGROUND

Fractional flow reserve (FFR) is an invasive method to assess the functional significance of coronary stenoses. The value of FFR in diabetic patients is controversial because of microvascular dysfunction. The aim of this study is to investigate the effect of diabetes mellitus (DM) on FFR measurements.

METHODS

One hundred and twenty-one patients with an intermediate lesion who had undergone FFR measurement were included in the study. Lesion severity was determined by quantitative coronary angiography. The patients were divided into groups according to the presence (group 1) or absence (group 2) of DM. The patients were further categorized according to the degree of luminal narrowing caused by the lesion (40-50, 51-60, and >60%) and reference vessel diameter (> or = 2.8 and <2.8 mm). FFR measurements were compared in each category.

RESULTS

There was no difference between the FFR values of diabetic and nondiabetic patients who had coronary lesions with similar degree of luminal narrowing (0.87+/-0.08 vs. 0. 0.85+/-0.07; 0.81+/-0.08 vs. 0.82+/-0.10; 0.81+/-0.10 vs. 0.83+/-0.09, P = 0.957). In the analysis comparing FFR measurements in the categories set according to reference vessel diameter, we did not find a difference either (0.82+/-0.09 vs. 0.83+/-0.09; 0.84+/-0.09 vs. 0.82+/-0.09, P = 0.878). The DeltaFFR value, which is the difference between FFR values before and after adenosine administration, was also similar in diabetic and nondiabetic patients (8.4+/-6.0 vs. 8.4+/-5.5, P = 0.997).

CONCLUSION

The presence of DM does not have a significant impact on FFR values in coronary stenoses of intermediate severity.