Value of fractional flow reserve in making decisions about bypass surgery for equivocal left main coronary artery disease

State-of-the-art percutaneous coronary intervention for left main coronary artery disease in Japan

Percutaneous coronary intervention for left main coronary artery disease (LM-PCI) represents a high-risk yet life-saving procedure that has evolved significantly over the years. This review outlines the current state-of-the-art practices for LM-PCI in Japan in detail, emphasizing the integration of coronary physiology and intracoronary imaging alongside with evidence-based standardized technique using latest drug-eluting stents. These advancements enable precise lesion assessment, stent sizing, and optimal deployment, thereby enhancing procedural safety and efficacy. Despite discrepancies between current guidelines favoring coronary artery bypass grafting and real-world practice trends towards increased LM-PCI adoption, particularly in elderly populations with multiple comorbidities, careful patient selection and procedural planning are critical. Future perspectives include further refining LM-PCI through conducting randomized controlled trials integrating advanced techniques and addressing the issue of ostial left circumflex lesions and nationwide standardization of medical care for LM disease.

Practical Application of Coronary Physiologic Assessment: Asia-Pacific Expert Consensus Document: Part 2

Coronary physiologic assessment is performed to measure coronary pressure, flow, and resistance or their surrogates to enable the selection of appropriate management strategy and its optimization for patients with coronary artery disease. The value of physiologic assessment is supported by a large body of clinical data that has led to major recommendations in all practice guidelines. This expert consensus document aims to convey practical and balanced recommendations and future perspectives for coronary physiologic assessment for physicians and patients in the Asia-Pacific region, based on updated information in the field that includes both wire- and image-based physiologic assessment. This is Part 2 of the whole consensus document, which provides theoretical and practical information on physiologic indexes for specific clinical conditions and patient statuses.

Applied coronary physiology for planning and guidance of percutaneous coronary interventions. A clinical consensus statement from the European Association of Percutaneous Cardiovascular Interventions (EAPCI) of the European Society of Cardiology

The clinical value of fractional flow reserve and non-hyperaemic pressure ratios are well established in determining an indication for percutaneous coronary intervention (PCI) in patients with coronary artery disease (CAD). In addition, over the last 5 years we have witnessed a shift towards the use of physiology to enhance procedural planning, assess post-PCI functional results, and guide PCI optimisation. In this regard, clinical studies have reported compelling data supporting the use of longitudinal vessel analysis, obtained with pressure guidewire pullbacks, to better understand how obstructive CAD contributes to myocardial ischaemia, to establish the likelihood of functionally successful PCI, to identify the presence and location of residual flow-limiting stenoses and to predict long-term outcomes. The introduction of new functional coronary angiography tools, which merge angiographic information with fluid dynamic equations to deliver information equivalent to intracoronary pressure measurements, are now available and potentially also applicable to these endeavours. Furthermore, the ability of longitudinal vessel analysis to predict the functional results of stenting has played an integral role in the evolving field of simulated PCI. Nevertheless, it is important to have an awareness of the value and challenges of physiology-guided PCI in specific clinical and anatomical contexts. The main aim of this European Association of Percutaneous Cardiovascular Interventions clinical consensus statement is to offer up-to-date evidence and expert opinion on the use of applied coronary physiology for procedural PCI planning, disease pattern recognition and post-PCI optimisation.

Determinants of functional significance of coronary bifurcation lesions and clinical outcomes after physiology-guided treatment

OBJECTIVES

To determine the rate of functionally significant (fractional flow reserve, FFR ≤ 0.80) coronary bifurcation stenoses that are considered anatomically significant based on angiographic estimation and to define predictors of functional significance of stenoses in main vessel and side branch.

BACKGROUND

To date, the rate of functionally significant stenoses in angiographic significant coronary bifurcation stenoses has not been specifically determined.

METHODS

Patients with significant angiographic bifurcation lesions defined as diameter stenosis >50% in main vessel and/or side branch were included. FFR was performed in main vessel (MV) and side branch (SB) before and after percutaneous coronary intervention (PCI). The protocol was approved by the local ethics committee.

RESULTS

Overall, 171 patients with bifurcation lesions were included. Mean FFR in MV was 0.80 ± 0.01 and 0.84 ± 0.09 in SB. 46% (n = 78) of bifurcation lesions were functionally significant when assessed with FFR. Diameter stenosis in main vessel, lesion length, side branch territory and SYNTAX score (SS) were found as predictors for lesion functional severity (main vessel FFR ≤ 0.80). At the time of follow-up, there were no differences between the treated and deferred group regarding rates of all-cause death, cardio-vascular death, MACEs and POCE.

CONCLUSION

Less than half of all angiographic significant bifurcation lesions were functionally significant when assessed with FFR. There was no difference in clinical outcomes at mean time of three years follow-up in treated and deferred lesion.

Correlation of Intravascular Ultrasound and Instantaneous Wave-Free Ratio in Patients With Intermediate Left Main Coronary Artery Disease

[Figure: see text].

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.

Physiology-Based Revascularization of Left Main Coronary Artery Disease

It is of critical importance to correctly assess the significance of a left main lesion. Underestimation of significance beholds the risk of inappropriate deferral of revascularization, whereas overestimation may trigger major but unnecessary interventions. This article addresses the invasive physiological assessment of left main disease and its role in deciding upon revascularization. It mainly focuses on the available evidence for fractional flow reserve and instantaneous wave-free ratio, their interpretation, and limitations. We also discuss alternative invasive physiological indices and imaging, as well as the link between physiology, ischemia, and prognosis.

The Role of Fractional Flow Reserve and Instantaneous Wave-Free Ratio Measurements in Patients with Acute Coronary Syndrome

PURPOSE OF REVIEW

The role of fractional flow reserve to guide revascularization in patients with stable angina is well established. The instantaneous wave-free ratio (iFR) is an emerging adenosine-free resting index that is non-inferior to FFR and has potential to streamline the functional evaluation of coronary artery disease. The feasibility and utility of intracoronary physiology in patients with acute coronary syndrome (ACS) is unclear. This review will discuss the physiological principles and validity of using FFR and iFR in patients presenting with ACS. We will also provide an overview of the available evidence for their role in guiding revascularization in this patient group.

RECENT FINDINGS

The use of intracoronary physiology in culprit lesions of patients presenting with STEMI is not recommended and its accuracy is uncertain in patients with NSTEMI. In contrast, the physiological assessment of non-culprit vessels with FFR and IFR is a reliable measure of lesion-specific ischemia. Recent studies have demonstrated that FFR-guided revascularization of non-culprit lesions improves clinical outcomes although the role of iFR in this patient cohort is unknown. Physiology-guided revascularization of non-culprit ACS lesions improves clinical outcomes. Future studies investigating the complementary role of plaque morphology, biomechanics, and systemic inflammation may provide clinicians with a more comprehensive framework to guide treatment decisions.

Reliability of Instantaneous Wave-Free Ratio (iFR) for the Evaluation of Left Main Coronary Artery Lesions

The assessment of the left main coronary artery (LMCA) by coronary angiography has several limitations. The fractional flow reserve (FFR) is useful for the functional evaluation of LMCA stenoses. The instantaneous wave-free ratio (iFR), a resting index, was developed to simplify functional coronary assessment. However, its performance for LMCA stenoses has yet to be explored. The iFR was measured at rest, and the FFR was measured under maximal hyperemia. We calculated that a sample size of 90 lesions would have provided 90% power at a 5% significance level to detect an Area Under the Curve (AUC) < 0.7 for the iFR to identify FFR-positive stenoses. A total of 91 measurements were performed on angiographically intermediate LMCA stenoses at three centers. The comparison between the iFR and the FFR showed a significant correlation (r = 0.67, p < 0.001). At receiver operating characteristic (ROC) analysis, the iFR revealed a good diagnostic performance when compared to the FFR (AUC = 0.84; p < 0.001). A classification agreement between the iFR and the FFR was recorded in 81% of cases. The left ventricular ejection fraction (LVEF) was an independent predictor of the discrepancy between the FFR and iFR values (p = 0.040). The present study is the first demonstrating that the assessment of LMCA stenoses with the instantaneous wave-free ratio is a reliable adenosine-free alternative to classic fractional flow reserve. If confirmed in larger populations, these findings could be of relevance for real world daily practice.

Evaluating Equivocal Left Main Stenosis with Fractional Flow Reserve – Not all Daughter Vessels are Created Equally

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Prognostic Value of Preserved Coronary Flow Velocity Reserve by Noninvasive Transthoracic Doppler Echocardiography in Patients With Angiographically Intermediate Left Main Stenosis

BACKGROUND

The potential of angiography to evaluate the hemodynamic severity of a left main coronary artery (LM) stenosis is limited. Noninvasive transthoracic Doppler echocardiographic coronary flow velocity reserve (CFVR) evaluation of intermediate coronary stenosis has demonstrated remarkably high negative prognostic value. The aim of this study was to assess clinical outcomes in patients with angiographically intermediate LM stenosis and preserved CFVR (>2.0) as evaluated by transthoracic Doppler echocardiographic CFVR.

METHODS

The initial study population included 102 patients with intermediate coronary stenosis of the LM referred for transthoracic Doppler echocardiographic CFVR assessment. Peak diastolic CFVR measurements were performed in the distal segment of the left anterior descending coronary artery after intravenous adenosine (140 μg/kg/min), and CFVR was calculated as the ratio between maximal hyperemic and baseline coronary flow velocity. Nineteen patients had impaired CFVR (≤2.0) and were excluded from further analysis, as well as two patients with poor acoustic windows. The final group consisted of 81 patients (mean age, 60 ± 9 years; 76 men) evaluated for adverse cardiac events including death, myocardial infarction, and revascularization.

RESULTS

Mean follow-up duration was 62 ± 26 months. Mean CFVR was 2.4 ± 0.4. Total event-free survival was 75 of 81 (92.6%), as six patients were referred for revascularization (five patients with coronary artery bypass grafting, one patient with percutaneous coronary intervention). There were no documented myocardial infarctions or cardiovascular deaths in the follow-up period.

CONCLUSIONS

In patients with angiographically intermediate and equivocal LM stenosis and preserved CFVR values of >2.0, revascularization can be safely deferred.

The role of FFR in clinical decision making in patients with moderate coronary lesions: a pilot study

Background and Aim: Applying fractional flow reserve (FFR) recently helped to assess borderline coronary defects and also facilitates assessment of these lesions. The present study aimed to assess cost-effectiveness of FFR in detection of these borderline lesions. Methods: This cross-sectional study was conducted on140 consecutive patients with 219 diseased arteries who underwent coronary angiography and suffered intermediate coronary lesions. Results: Of 18 patients who candidate for CABG before FFR, only one patient underwent CABG after determining FFR (P-value<0.05), while 15 patients were scheduled for PCI and 2 patients for medical treatment. Of 122 patients who candidate for PCI, 59 were programmed to underwent PCI after FFR determination (P-value<0.05), while the strategy in 63 patients (47 with one-vessel disease, 15 with two vessel diseases, and 1 with three vessel diseases) was modified to medical treatment. Considering strategy modifying from PCI to medical treatment, 101 stents were saved (P-value<0.05). Also, in change of strategy from CABG to PCI, spending has decreased as much as 77.3% (P-value<0.05). Furthermore, the change of treatment approach from PCI on much number of coronary vessels to PCI on less number of coronary lesions led to saving of 52.2% of costs (P-value<0.05). Conclusions:In patients with an intermediate coronary lesion, measuring FFR to guide the decision to determine treatment strategy may lead to significant cost savings. (www.actabiomedica.it)

Assessing the left main stem in the cardiac catheterization laboratory. What is "significant"? Function, imaging or both?

Revascularization of significant Left Main Stem (LMS) disease improves clinical outcomes. This can be achieved through either Coronary Artery Bypass Grafting or Percutaneous coronary intervention. Defining a significant stenosis of the LMS can be challenging and debatable, as most data have been derived using angiographic assessment alone, with a threshold of 50% luminal stenosis used as a marker of functional significance. The use of adjunctive technologies like Intravascular Ultrasound and Fractional Flow Reserve has improved our ability to accurately assess the anatomical severity and physiological significance of coronary artery stenoses, much more so, than can be achieved through conventional angiography alone. An improved assessment of LMS disease through these adjunctive techniques offers procedural and clinical benefits. Rather than focus on the preferred methods of revascularisation, this article aims to highlight the common pitfalls and misconceptions in the assessment of LMS stenoses. We also propose a simple algorithm for the assessment of LMS disease to help guide revascularisation decisions.

Left main coronary artery stenosis: severity evaluation and implications for management

INTRODUCTION

The significant stenosis of the left main coronary artery is associated with poor outcomes and is considered a strong indication for revascularization. However, deciding whether the stenosis is significant can sometimes be challenging, especially when the degree of stenosis is intermediate, and can necessitate additional tests and imaging modalities. Areas covered: We did a literature search using keywords like 'left main', 'imaging', 'intravascular ultrasound', 'fractional flow reserve', 'computed tomographic angiography' and 'magnetic resonance imaging'. The most commonly used methods for better characterizing intermediate left main coronary stenoses are intravascular ultrasound and fractional flow reserve, while optical coherence tomography is the newer technique that provides better images, but for which not as much data is available. The noninvasive techniques are coronary computed tomographic angiography and, to a lesser degree, coronary magnetic resonance imaging. Expert commentary: Accurately determining the severity of left main coronary stenosis can mean the difference between a major intervention and conservative therapy. The reviewed newer imaging modalities give us greater confidence that patients with left main stenosis are assigned to the right treatment modality.

The impact of downstream coronary stenosis on fractional flow reserve assessment of intermediate left main coronary artery disease: human validation

OBJECTIVES

The aim of this study was to determine the impact of downstream coronary stenosis in the left anterior descending coronary artery (LAD) or left circumflex coronary artery (LCx) on the assessment of fractional flow reserve (FFR) across an intermediate left main coronary artery (LMCA) stenosis in humans with the pressure wire positioned in the nondiseased downstream vessel.

BACKGROUND

Accurate assessment of intermediate LMCA disease is critical for guiding decisions regarding revascularization. In theory, FFR across an intermediate LMCA stenosis will be affected by downstream disease, even if the pressure wire is positioned in the nondiseased downstream vessel.

METHODS

After percutaneous coronary intervention of the LAD, LCx, or both, an intermediate LMCA stenosis was created with a deflated balloon catheter. FFR was measured in the LAD and LCx coronary arteries before and after creation of downstream stenosis by inflating an angioplasty balloon within the newly placed stent. The true FFR (FFRtrue) of the LMCA, measured in the nondiseased downstream vessel in the absence of stenosis in the other vessel, was compared with the apparent FFR (FFRapp) measured in the presence of stenosis.

RESULTS

In 25 patients, 91 pairs of measurements were made, 71 with LAD stenosis and 20 with LCx stenosis. FFRtrue of the LMCA was significantly lower than FFRapp (0.81 ± 0.08 vs. 0.83 ± 0.08, p < 0.001), although the numerical difference was small. This difference correlated with the severity of the downstream disease (r = 0.35, p < 0.001). In all cases in which FFRapp was >0.85, FFRtrue was >0.80.

CONCLUSIONS

In most cases, downstream disease does not have a clinically significant impact on the assessment of FFR across an intermediate LMCA stenosis with the pressure wire positioned in the nondiseased vessel.

Clinical Relevance of Coronary Fractional Flow Reserve: Art-of-state

Objective:

The objective was to delineate the current knowledge of fractional flow reserve (FFR) in terms of definition, features, clinical applications, and pitfalls of measurement of FFR.

Data Sources:

We searched database for primary studies published in English. The database of National Library of Medicine (NLM), MEDLINE, and PubMed up to July 2014 was used to conduct a search using the keyword term “FFR”.

Study Selection:

The articles about the definition, features, clinical application, and pitfalls of measurement of FFR were identified, retrieved, and reviewed.

Results:

Coronary pressure-derived FFR rapidly assesses the hemodynamic significance of individual coronary artery lesions and can readily be performed in the catheterization laboratory. The use of FFR has been shown to effectively guide coronary revascularization procedures leading to improved patient outcomes.

Conclusions:

FFR is a valuable tool to determine the functional significance of coronary stenosis. It combines physiological and anatomical information, and can be followed immediately by percutaneous coronary intervention (PCI) if necessary. The technique of FFR measurement can be performed easily, rapidly, and safely in the catheterization laboratory. By systematic use of FFR in dubious stenosis and multi-vessel disease, PCI can be made an even more effective and better treatment than it is currently. The current clinical evidence for FFR should encourage cardiologists to use this tool in the catheterization laboratory.

New Invasive Assessment Measures of Coronary Artery Disease Severity

Ischemic heart disease is the leading cause of mortality worldwide. The assessment and treatment of patients with ischemic heart disease have advanced greatly over the past decade. Particular attention has been given recently to the recognition of lesions that cause ischemia or that are prone to plaque rupture. New invasive measures of coronary artery disease have been developed, including fractional flow reserve, intravascular ultrasound, optical coherence tomography, and most recently, near-infrared spectroscopy. These technologies have helped to guide the assessment of hemodynamically significant lesions and have shown particular promise in guiding percutaneous coronary interventions. However, mortality and the rate of revascularization have shown mixed results to date. This review seeks to investigate the use and potential benefit of these technologies, with particular attention to clinical end points.

Update on percutaneous intervention for left main coronary artery stenosis

Percutaneous coronary intervention (PCI) using drug-eluting stents (DES) is currently considered as a viable alternative to coronary artery bypass graft surgery (CABG) for selected patients with left main coronary artery disease. The updated results of the landmark randomized trials comparing CABG versus PCI demonstrated comparable 5-year outcomes and are in line with the current guidelines that designate PCI as a reasonable treatment in this disease subset. Given that the completed randomized trials did not include contemporary DESs, the upcoming results of the ongoing trials evaluating the performance of new-generation DES compared with CABG (such as the EXCEL trial), may further help to clarify the current role and future recommendations of PCI for left main coronary artery disease. Apart from the recent stent technology, further improvements in outcomes after PCI may be possible when it is used with an integrated approach that combines functional concepts for decision-making, adjunctive imaging support and optimal pharmacotherapies.

Value of FFR in clinical practice

Fractional flow reserve is an important tool in the cardiac catheterization lab to assess the physiological significance of coronary lesions. This article discusses the basic concepts about FFR and its utility in clinical decision making.

Evaluating the impact of fractional flow reserve-guided percutaneous coronary intervention in intermediate coronary artery lesions on the mode of treatment and their outcomes: An Iranian experience

BACKGROUND

Today, the fractional flow reserve (FFR) guides the physician to select suitable patients with intermediate severity coronary lesions in angiography that should be treated or not with stent. The aim of this study was to evaluate the impact of using FFR in the selection of appropriate treatment strategy in angiographic intermediate coronary lesions and their short-term outcome in a sample of Iranian population.

METHODS

In a prospective cohort, 34 patients who had intermediate coronary artery lesion(s), defined as having a 40-70% diameter stenosis, as determined by visual estimation or quantitative coronary angiography were enrolled through a convenience sampling method. All patients underwent FFR measurement to decide whether percutaneous coronary intervention should be performed. The results of visual assessment, quantitative coronary angiography, and functional assessment of the severity of coronary stenosis were compared. Significant stenosis was defined as FFR < 0.80. All patients were followed for 6 months for the incidence of major advanced cardiac events.

RESULTS

In this study, 34 patients (22 male and 12 female) with mean age of 57 ± 8 (range 45-70) were included. In 26.47% (9/34) of patients, FFR was < 0.80, they underwent coronary angioplasty. The correlation between visual estimation and quantitative assessment of lesion diameter was 0.804 (P < 0.001). During the follow-up period, no major advanced cardiac events were reported. In addition, 5.88 (2/34) of patients had a left main (LM) lesion with FFR > 0.80 and stenting was done to the other vessels with significant coronary lesions.

CONCLUSION

Measurement of FFR is a useful approach in making clinical decisions about revascularization procedures in patients with moderate coronary artery lesion severity, especially in LM and multivessel disease. This study showed that not only FFR can change treatment plan of the patients, but also it would improve clinical outcomes.

Left main coronary artery disease: importance, diagnosis, assessment, and management

Left main coronary disease is seen in 4%-6% of patients undergoing coronary angiography for an ischemic evaluation and is a potentially fatal condition if not promptly identified and treated. Recent studies have increased our understanding of the complexity of left main coronary artery disease. This lesion subset offers numerous challenges in diagnosis and management. Fractional flow reserve and intravascular ultrasound are important adjuncts to angiography to determine the significance of ambiguous lesions of the left main coronary artery. Surgery is associated with much better outcomes than medical therapy and is considered by many to be the standard of care in patients who are surgical candidates. Recent studies comparing surgery with percutaneous coronary intervention (PCI) have defined subgroups with lesser extent of disease burden that may do just as well with PCI. Challenges remain in the management of bifurcation disease, and the interventional community anxiously awaits the results of the large-scale randomized trials comparing PCI with surgery.

Drug-eluting stents in unprotected left main coronary artery disease

Though coronary bypass graft surgery (CABG) has traditionally been the cornerstone of therapy in patients with unprotected left main coronary artery (ULMCA) disease, recent evidence supports the use of percutaneous coronary intervention in appropriate patients. Indeed in patients with ULMCA disease, drug-eluting stents (DES) have shown similar incidence of hard end points, fewer periprocedural complications and lower stroke rates compared with CABG, though at the cost of increased revascularization with time. Furthermore, the availability of newer efficacious and safer DES as well as improvements in diagnostic tools, percutaneous techniques and, importantly, a better patient selection, allowed percutaneous coronary intervention a viable alternative to CABG of left main-patients with low disease complexity; however, even in this interventional era characterized by efficacious DES, patients with ULMCA disease remain a challenging high-risk population where outcomes strongly depend on clinical characteristics, anatomical disease complexity and extension and operator's experience. This review summarizes the role of DES in ULMCA disease patients.

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.

Prevalence, location, and extent of significant coronary artery disease in patients with normal myocardial perfusion imaging

BACKGROUND

False-negative myocardial perfusion imaging (MPI) can by due to left main (LM) or three-vessel disease causing "balanced ischemia". However, so far prevalence of LM or three-vessel-disease in patients with normal MPI is unclear. We assessed prevalence, location, and extent of significant coronary artery disease (CAD) in patients with normal MPI.

METHODS

Between 2006 and 2010, 256 patients with normal MPI who had invasive angiography because of persisting or worsening of the same initial symptoms were studied. Significant CAD was defined as stenosis > 70% or LM > 50%.

RESULTS

A total of 93 patients (36%) had significant CAD. Significant CAD was observed more frequently in males, higher age and those with typical angina complaints. Significant LM disease was present in 7%, three-vessel disease in 10%, two-vessel disease in 22%, and single vessel disease (not left main) in 61%. In those with single vessel disease, the location was the LAD in 40%, the RCA in 30%, and the LCX in 30%.

CONCLUSIONS

In selected patients with normal MPI, one-third had significant CAD. The majority of these patients had single vessel disease (not left main). LM or three vessel disease, causing "balanced ischemia", is a less common cause of false-negative MPI.

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.

Role of intravascular ultrasound in unprotected left main percutaneous coronary intervention

Percutaneous coronary intervention (PCI) to the unprotected left main stem offers an attractive alternative to bypass grafting, but is associated with a significant clinical risk and therefore demands special consideration. Successful left main PCI is dependent upon the morphology of the lesion and the technical quality of the procedure. For these reasons, intravascular ultrasound (IVUS) has been the most popular adjunct to coronary angiography during left main PCI. However, trials of IVUS in left main PCI have produced inconclusive results, and most data predate the use of drug-eluting stents. Despite this, IVUS offers practical benefits in both case selection, and in guiding angioplasty and stenting. Here, we review the arguments for the present and future role of IVUS in left main PCI.

The CABG SYNTAX Score - an angiographic tool to grade the complexity of coronary disease following coronary artery bypass graft surgery: from the SYNTAX Left Main Angiographic (SYNTAX-LE MANS) substudy

AIMS

The SYNTAX Score (SXscore) has established itself as an important prognostic tool in patients undergoing percutaneous coronary intervention (PCI). A limitation of the SXscore is the inability to differentiate outcomes in patients who have undergone prior coronary artery bypass graft (CABG) surgery. The CABG SXscore was devised to address this limitation.

METHODS AND RESULTS

In the SYNTAX-LE MANS substudy 115 patients with unprotected left main coronary artery disease (isolated or associated with one, two or three-vessel disease) treated with CABG were prospectively assigned to undergo a 15-month coronary angiogram. An independent core laboratory analysed the baseline SXscore prior to CABG. The 15-month CABG SXscore was calculated by a panel of three interventional cardiologists. The CABG SXscore was calculated by determining the standard SXscore in the "native" coronary vessels ("native SXscore") and deducting points based on the importance of the diseased coronary artery segment (Leaman score) that have a functioning bypass graft anastomosed distally. Points relating to intrinsic coronary disease, such as bifurcation disease or calcification, remain unaltered. The mean 15-month CABG SXscore was significantly lower compared to the mean baseline SXscore (baseline SXscore 31.6, SD 13.1; 15-month CABG SXscore 21.2, SD 11.1; p<0.001). Reproducibility analyses (kappa [k] statistics) indicated a substantial agreement between CABG SXscore measurements (k=0.70; 95% CI [0.50-0.90], p<0.001), with the points deducted to calculate the CABG SXscore the most reproducible measurement (k=0.74; 95% CI [0.53-0.95], p<0.001). Despite the limited power of the study, four-year outcome data (Kaplan-Meier curves) demonstrated a trend towards reduced all-cause death (9.1% vs. 1.8%, p=0.084) and death/CVA/MI (16.4% vs. 7.0%, p=0.126) in the low compared to the high CABG SXscore group.

CONCLUSIONS

In this pilot study the calculation of the CABG SXscore appeared feasible, reproducible and may have a long-term prognostic role in patients with complex coronary disease undergoing surgical revascularisation. Validation of this new scoring methodology is required.

Fractional flow reserve application in everyday practice: adherence to clinical recommendations

Fractional flow reserve (FFR) is considered the gold standard for invasive assessment of functional, significant coronary stenosis. Nevertheless, its application and outcome in daily practice is rarely reported. We investigated whether decisions in clinical practice adhered to FFR-generated recommendations and whether FFR influenced cardiovascular outcomes. This retrospective, observational, cohort study included 189 patients that underwent FFR measurements during coronary angiography at our institution The median follow up was 27 months (range, 7-112 months). Clinical outcomes (up to 2 years) included all-cause mortality, cardiac-mortality, and major adverse cardiac events (MACE) which comprised cardiac mortality, non-fatal MI, target vessel revascularization, and coronary artery bypass graft (CABG). Patients most frequently presented with unstable angina (74.6%). Only 55 patients (29.1%) exhibited significant functional stenosis (FFR ≤0.8). Nevertheless, 68 patients (36%) underwent immediate coronary interventions; 64% were deferred from revascularization procedures and managed conservatively with optimal medical treatment. Thirty-five patients (18.5%) were treated in discordance with FFR results, but the overall MACE rate was similar to that of patients treated in concordance with FFR results (8.3% vs. 8.6%, P=0.41). In conclusion, in our everyday practice, the operator's decision was in discordance to the FFR measurements and indications in nearly 20% of cases. In these selected cases, the operator's subjective judgment may continue to play an important role.

The effect of aortic wall and aortic leaflet stiffening on coronary hemodynamic: a fluid-structure interaction study

Pathologies of the aortic valve such as aortic sclerosis are thought to impact coronary blood flow. Recent clinical investigations have observed simultaneous structural and hemodynamic variations in the aortic valve and coronary arteries due to regional pathologies of the aortic valve. The goal of the present study is to elucidate this observed and yet unexplained phenomenon, in which a local pathology in the aortic valve region could potentially lead to the initiation or progression of coronary artery disease. Results revealed a considerable impact on the coronary flow, velocity profile, and consequently shear stress due to an increase in the aortic wall or aortic leaflet stiffness and thickness which concur with clinical observations. The cutoff value of 0.75 for fractional flow reserve was reached when the values of leaflet thickness and aortic wall stiffness were approximately twice and three times their normal value, respectively. Variations observed in coronary velocity profiles as well as wall shear stress suggest a possible link for the initiation of coronary artery disease.