Fractional Flow Reserve-Guided Revascularization in Patients With Aortic Stenosis

Aortic Stenosis With Coronary Artery Disease: SAVR or TAVR-When and How?

The growing number of candidates for transcatheter aortic valve replacement (TAVR) has increased the interest in the concomitant presence of coronary artery disease (CAD) and severe aortic stenosis (AS), prompting the need to define the appropriate revascularization strategy for each case. The reported prevalence of concurrent AS and CAD has varied over the years on the basis of the CAD definition and the population evaluated. Revascularization for treating CAD in patients with severe AS involves additional interventions that could impact outcomes. The addition of coronary artery bypass grafting (CABG) to surgical aortic valve replacement (SAVR) has demonstrated favourable effects on long-term prognosis, while the impact of adding percutaneous coronary intervention (PCI) to TAVR may depend on the CAD complexity and the feasibility of achieving complete or reasonably incomplete revascularization. Furthermore, the comparison between SAVR+CABG and TAVR+PCI in low-intermediate surgical risk and low-intermediate complex CAD patients did not reveal differences in all-cause mortality or stroke between the groups. However, there is some evidence showing a lower incidence of major cardiovascular events with the SAVR+CABG strategy for patients with complex CAD. Thus, SAVR+CABG seems to be the best option for patients with low-intermediate surgical risk and complex CAD, and TAVR+PCI for high surgical risk patients seeking complete and/or reasonable incomplete revascularization. After deciding between TAVR+PCI or SAVR+CABG, factors such as timing for PCI, low ejection fraction, coronary reaccess, and valve durability must be considered. Finally, alternative methods for assessing CAD severity are currently under evaluation to ascertain their real value for guiding revascularization in patients with severe AS with CAD.

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.

Fractional flow reserve use in coronary artery revascularization: A systematic review and meta-analysis

Fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) is recommended in revascularization guidelines for intermediate lesions. However, recent studies comparing FFR-guided PCI with non-physiology-guided revascularization have reported conflicting results. PubMed and Embase were searched for studies comparing FFR-guided PCI with non-physiology-guided revascularization strategies (angiography-guided, intracoronary imaging-guided, coronary artery bypass grafting). Data were pooled by meta-analysis using random-effects model. 26 studies enrolling 78,897 patients were included. FFR-guided PCI as compared to non-physiology-guided coronary revascularization had lower risk of all-cause mortality (odds ratio [OR] 0.79 95% confidence interval [CI] 0.64-0.99, I² = 53%) and myocardial infarction (MI) (OR 0.74 95% CI 0.59-0.93, I² = 44.7%). However, no differences between groups were found in terms of major adverse cardiac events (MACEs) (OR 0.86 95% CI 0.72-1.03, I² = 72.3%) and repeat revascularization (OR 1 95% CI 0.82-1.20, I² = 43.2%). Among patients with coronary artery disease (CAD), FFR-guided PCI as compared to non-physiology-guided revascularization was associated with a lower risk of all-cause mortality and MI.

Management of coronary artery disease in patients undergoing transcatheter aortic valve implantation. A clinical consensus statement from the European Association of Percutaneous Cardiovascular Interventions in collaboration with the ESC Working Group on Cardiovascular Surgery

Significant coronary artery disease (CAD) is a frequent finding in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation (TAVI), and the management of these two conditions becomes of particular importance with the extension of the procedure to younger and lower-risk patients. Yet, the preprocedural diagnostic evaluation and the indications for treatment of significant CAD in TAVI candidates remain a matter of debate. In this clinical consensus statement, a group of experts from the European Association of Percutaneous Cardiovascular Interventions (EAPCI) in collaboration with the European Society of Cardiology (ESC) Working Group on Cardiovascular Surgery aims to review the available evidence on the topic and proposes a rationale for the diagnostic evaluation and indications for percutaneous revascularisation of CAD in patients with severe aortic stenosis undergoing transcatheter treatment. Moreover, it also focuses on commissural alignment of transcatheter heart valves and coronary re-access after TAVI and redo-TAVI.

Quantitative flow ratio for evaluation of borderline coronary lesions in patients with severe aortic stenosis

INTRODUCTION AND OBJECTIVES

Quantitative flow ratio (QFR) is a novel noninvasive method for evaluating coronary physiology. However, data on the QFR in patients with aortic stenosis (AS) and coronary artery disease are scarce. Thus, we compared the diagnostic performance of the QFR with that of the resting distal to aortic coronary pressure (Pd/Pa) ratio, fractional flow reserve (FFR), and instantaneous wave-free ratio (iFR), as well as angiographic indices.

METHODS

A total of 221 AS patients with 416 vessels undergoing FFR/iFR measurements were enrolled in the study.

RESULTS

The mean percent diameter stenosis (%DS) was 58.6%±13.4% and the mean Pd/Pa ratio, FFR, iFR, and QFR were 0.95±0.03, 0.85±0.07, 0.90±0.04, and 0.84±0.07, respectively. A FFR ≤ 0.80 was noted in 26.0% of interrogated vessels, as well as an iFR ≤ 0.89 in 33.2% and QFR ≤ 0.80 in 31.7%. The QFR had better agreement with FFR (intraclass correlation coefficient [ICC], 0.96; 95% confidence interval [95%CI], 0.95-0.96) than with the iFR (ICC, 0.79; 95%CI, 0.75-0.82) and Pd/Pa ratio (ICC, 0.52; 95%CI, 0.44-0.58). In addition, the QFR showed better diagnostic accuracy (98.6% vs 94.2%; P <.001) and discriminant function (area under the curve=0.996 vs 0.988; P <.001) when the iFR was used as the reference instead of FFR.

CONCLUSIONS

In patients with AS, the QFR has good agreement with both FFR and iFR. However, the agreement appears to be even better when the iFR is used as the reference, presumably due to the complex nature of the coronary physiology in the assessment of coronary artery disease in patients with severe AS.

Fractional Flow Reserve: Patient Selection and Perspectives

The aim of this review was to discuss the current practice and patient selection for invasive FFR, new techniques to estimate invasive FFR and future of coronary physiology tests. We elaborate on the indication and application of FFR and on the contraindications and concerns in certain patient populations.

Fractional flow reserve guided versus angiographic guided surgical revascularization: A meta-analysis

BACKGROUND

Clinical benefits of FFR (Fraction Flow Reserve) driven CABG (Coronary Artery Bypass Graft) remain to be established.

METHODS

All randomized controlled trials (RCTs) and observational studies with multivariable adjustement were included. MACE (Major Adverse Cardiac Events) was the primary end point, while its single components (death, myocardial infarction, and total vessel revascularization [TVR]) along with number of anastomoses, on pump procedures and graft occlusion at angiographic follow-up were the secondary ones. Each analysis was stratified for RCTs versus observational studies.

RESULTS

Four studies (two RCTs and two observational) were included, enrolling 983 patients, 542 angio-guided and 441 FFR-guided. Mean age was 68.45 years, 79% male, with a mean EuroSCORE I of 2.7. Coronary lesions were located in 37% of patients in the left anterior descending artery, 32% in the circumflex artery, and 26% in the right coronary artery. After a mean follow-up of 40 months, risk of MACE did not differ (OR 0.86 [0.63-1.18]) as that of all cause death (OR 0.86 [0.59-1.25]), MI (OR 0.57 [0.30-1.11]) and TVR (OR 1.10 [0.65-1.85]). FFR-driven CABG reduced on-pump procedures (OR 0.58 [0.35-0.93]) and number of anastomoses (-0.40 [-0.80: -0.01]) while incidence of graft occlusion at follow-up did not differ (OR 0.59 [0.30-1.15], all CI 95%).

CONCLUSION

Fraction flow reserve driven CABG reduced the number of anastomoses and of on-pump procedures without increasing risk of MACE and without reducing graft occlusion at angiographic follow-up. ID CRD42020211945.

Fractional flow reserve in patients with reduced ejection fraction

AIMS

Fractional flow reserve (FFR) has never been investigated in patients with reduced ejection fraction and associated coronary artery disease (CAD). We evaluated the impact of FFR on the management strategies of these patients and related outcomes.

METHODS AND RESULTS

From 2002 to 2010, all consecutive patients with left ventricular ejection fraction (LVEF) ≤50% undergoing coronary angiography with ≥1 intermediate coronary stenosis [diameter stenosis (DS)% 50-70%] treated based on angiography (Angiography-guided group) or according to FFR (FFR-guided group) were screened for inclusion. In the FFR-guided group, 433 patients were matched with 866 contemporary patients of the Angiography-guided group. For outcome comparison, 617 control patients with LVEF >50% were included. After FFR, stenotic vessels per patient were significantly downgraded compared with the Angiography-guided group (1.43 ± 0.98 vs. 1.97 ± 0.84; P < 0.001). This was associated with lower revascularization rate (52% vs. 62%; P < 0.001) in the FFR-guided vs. the Angiography-guided group. All-cause death at 5 years of follow-up was significantly lower in the FFR-guided as compared with Angiography-guided group [22% vs. 31%. HR (95% CI) 0.64 (0.51-0.81); P < 0.001]. Similarly, rate of major adverse cardiovascular and cerebrovascular events (MACCE: composite of all-cause death, myocardial infarction, revascularization, and stroke) was significantly lower in the FFR-guided group [40% vs. 46% in the Angiography-guided group. HR (95% CI) 0.81 (0.67-0.97); P = 0.019]. Higher rates of death and MACCE were observed in patients with reduced LVEF compared with the control cohort.

CONCLUSIONS

In patients with reduced LVEF and CAD, FFR-guided revascularization was associated with lower rates of death and MACCE at 5 years as compared with the Angiography-guided strategy. This beneficial impact was observed in parallel with less coronary artery bypass grafting and more patients deferred to percutaneous coronary intervention or medical therapy.

Pathophysiology, Diagnosis, and Treatment of Patients with Concomitant Severe Aortic Stenosis and Coronary Artery Disease: A Closer Look to the Unresolved Perplexity

Degenerative aortic stenosis (AS) and coronary artery disease (CAD) are the most prevalent cardiovascular diseases in developed countries, and they coexist in up to 50% of patients. The pathophysiological rationale behind concomitant AS and CAD is discussed in detail in this review, together with prognostic implications. Detecting CAD in patients with AS may be challenging, as AS may mask the existence and symptoms of CAD. The safety and reliability of invasive and non-invasive physiological assessment for epicardial coronary disease are also a matter of debate. Finally, the selection and timing of optimal treatment of CAD in patients with severe AS are still unclear. Given the aging of the population, the increase in the prevalence of AS, and the ongoing paradigm shift in its treatment, controversies in the diagnosis and treatment of CAD in the setting of AS are deemed to grow in importance. In this paper, we present contemporary issues in the diagnosis and management of CAD in patients with severe AS who are transcatheter aortic valve implantation (TAVI) candidates and provide perspective on the treatment approach.

Aortic Valve Disease and Associated Complex CAD: The Interventional Approach

Coronary artery disease (CAD) is highly prevalent in patients with severe aortic stenosis (AS). The management of CAD is a central aspect of the work-up of patients undergoing transcatheter aortic valve implantation (TAVI), but few data are available on this field and the best percutaneous coronary intervention (PCI) practice is yet to be determined. A major challenge is the ability to elucidate the severity of bystander coronary stenosis independently of the severity of aortic valve stenosis and subsequent impact on blood flow. The prognostic role of CAD in patients undergoing TAVI is being still debated and the benefits and the best timing of PCI in this context are currently under evaluation. Additionally, PCI in the setting of advanced AS poses some technical challenges, due to the complex anatomy, risk of hemodynamic instability, and the increased risk of bleeding complications. This review aims to provide a comprehensive synthesis of the available literature on myocardial revascularization in patients with severe AS undergoing TAVI. This work can assist the Heart Team in individualizing decisions about myocardial revascularization, taking into account available diagnostic tools as well as the risks and benefits.

Coronary Microcirculation in Aortic Stenosis: Pathophysiology, Invasive Assessment, and Future Directions

With the increasing prevalence of aortic stenosis (AS) due to a growing elderly population, a proper understanding of its physiology is paramount to guide therapy and define severity. A better understanding of the microvasculature in AS could improve clinical care by predicting left ventricular remodeling or anticipate the interplay between epicardial stenosis and myocardial dysfunction. In this review, we combine five decades of literature regarding microvascular, coronary, and aortic valve physiology with emerging insights from newly developed invasive tools for quantifying microcirculatory function. Furthermore, we describe the coupling between microcirculation and epicardial stenosis, which is currently under investigation in several randomized trials enrolling subjects with concomitant AS and coronary disease. To clarify the physiology explained previously, we present two instructive cases with invasive pressure measurements quantifying coexisting valve and coronary stenoses. Finally, we pose open clinical and research questions whose answers would further expand our knowledge of microvascular dysfunction in AS. These trials were registered with NCT03042104, NCT03094143, and NCT02436655.

Coronary Microcirculation in Aortic Stenosis

Aortic stenosis is a heterogeneous disorder. Variations in the pathological and physiological responses to pressure overload are incompletely understood and generate a range of flow and pressure gradient patterns, which ultimately cause varying microvascular effects. The impact of cardiac-coronary coupling depends on these pressure and flow effects. In this article, we explore important concepts concerning cardiac physiology and the coronary microcirculation in aortic stenosis and their impact on myocardial remodeling, aortic valve flow patterns, and clinical progression.

The Influence of Aortic Valve Obstruction on the Hyperemic Intracoronary Physiology: Difference Between Resting Pd/Pa and FFR in Aortic Stenosis

The reliability of fractional flow reserve (FFR) in aortic stenosis (AS) has been questioned because of the uncertain response to vasodilators. A retrospective multicenter cohort of 114 AS patients who underwent coronary physiology assessment was compared with 154 controls before and after propensity matching adjustment. The difference between resting distal coronary vs aortic pressure ratio (Pd/Pa) and FFR (ΔPd/Pa-FFR) was tested against the severity of AS. ΔPd/Pa-FFR was not influenced by the severity of AS in terms of aortic valve area (r = - 0.02, p = 0.83) and gradient (r = - 0.05, p = 0.64) or by the left ventricle hypertrophy (r = - 0.03, p = 0.88). Conversely, ΔPd/Pa-FFR was influenced by the presence of diabetes (r = - 0.24, p = 0.005), peripheral vascular disease (r = - 0.16, p = 0.047), and chronic kidney disease (r = - 0.19, p = 0.03). No significant difference was observed in the ΔPd/Pa-FFR between patients with AS and matched controls. Further studies are warranted to validate the FFR-guided revascularization in patients with AS.

Impact of residual coronary atherosclerosis on transfemoral transcatheter aortic valve replacement

OBJECTIVES

This study reports on the clinical effects of complete vs incompletely revascularized coronary artery disease on transcatheter aortic valve replacement (TAVR).

BACKGROUND

There is a high prevalence of active coronary artery disease (CAD) in patients undergoing TAVR but preemptive revascularization remains controversial.

METHODS

Patients were categorized into three cohorts: complete revascularization (CR), incomplete revascularization of a major epicardial artery (IR Major), and incomplete revascularization of a minor epicardial artery only (IR Minor). When feasible, SYNTAX scoring was performed for exploratory analysis. Analyses were performed using Cox proportional hazard models and Kaplan-Meier method.

RESULTS

A total of 323 patients with active CAD were included. Adjusted outcomes showed that patients with IR Major had increased incidence of acute myocardial infarction (AMI) or revascularization compared with those in the CR cohort (HR 3.72, P = 0.048). No difference was noted in all-cause mortality or all-cause readmission rates. Exploratory secondary analysis with residual SYNTAX scores showed a significant interaction between disease burden and AMI/revascularization, as well as all-cause readmission. All-cause mortality remained unaffected based on residual SYNTAX scores.

CONCLUSIONS

This is a retrospective single-center study reporting on pre-TAVR revascularization outcomes in patients with active CAD. In this analysis, we found that patients undergoing TAVR benefited from achieving complete revascularization to abate future incidence of AMI/revascularization. Despite this finding, all-cause mortality remained unaffected. Future efforts should focus on the role of functional assessment of the coronaries, as well as the long-term effects of complete revascularization in a larger patient cohort.

Evaluation of the cut-off value for the instantaneous wave-free ratio of patients with aortic valve stenosis

The aim of this study was to examine the clinical value of iFR for AS patients. Functional evaluation of coronary stenosis in patients with aortic valve stenosis (AS) is challenging because the stress-induced test is often thought to be a contraindication. AS patients have a unique coronary flow pattern dependent on the diastolic phase. The instantaneous wave-free ratio (iFR) is a vasodilator-free, invasive pressure wire index of the functional severity of coronary stenosis and is calculated under resting conditions. And iFR calculated during a specific period of diastole may have the potential benefit to assess the functional severity of coronary stenosis in AS patients. We examined 158 consecutive patients (217 stenoses) whose iFR and fractional flow reserve (FFR) were measured simultaneously. Among the 158 patients, AS was observed in 13 (8.2%). The iFR showed good correlation with FFR in AS patients. The best cut-off value of iFR for the receiver-operator curve analysis to predict FFR of 0.8 was 0.9 for non-AS patients. However, it was 0.73 for AS patients. The present study demonstrated good correlation between iFR and FFR for AS patients. Vasodilator-free assessment using iFR may provide potential benefits when evaluating coronary stenosis in patients with AS. In AS patients, the best cut-off of iFR value predicting FFR value of 0.8 was lower than 0.9 that is the standard predictive value of iFR.

To revascularize or not before transcatheter aortic valve implantation?

Concomitant coronary artery disease (CAD) and aortic stenosis occur in approximately 60-75% of patients referred for surgical or transcatheter aortic valve replacement (TAVR). Current guidelines support simultaneous surgical aortic valve replacement and bypass surgery with a class IIa recommendation, based on observational, non-randomized data. With the inception of TAVR, this strategy has been challenged, as observational studies have not shown significant outcome differences in patients with and without CAD treated with TAVR. Performing percutaneous coronary intervention (PCI) in patients with aortic stenosis is safe, but the indication and timing remain controversial. Complete revascularization before TAVR with low residual Syntax score (<8) may be considered in selected cases with extensive, proximal, and severe CAD to improve outcomes. PCI before TAVR may require less contrast and reduce the risk of acute kidney injury, but uninterrupted dual antiplatelet therapy may increase the risk of bleeding during TAVR. Combined PCI and TAVR can be considered for unstable patients with simple lesions or ostial lesions, with risk of coronary occlusion after deployment of the transcatheter heart valve. PCI after TAVR may be considered in patients who remain symptomatic with significant residual ischemia despite optimal medical therapy. In the near future, it is expected that randomized clinical trials will further clarify the indications and role of revascularization in patients undergoing TAVR. In this article we provide an extensive review on the management of CAD in TAVR candidates, including additional considerations on technical aspects, device selection, and adjunctive pharmacological therapies.

Should functional assessment of lesion severity be used to guide coronary bypass?

PURPOSE OF REVIEW

The purpose of this article is to investigate the potential role of fractional flow reserve (FFR) to guide surgical revascularization.

RECENT FINDINGS

Coronary artery bypass is planned and executed primarily based on angiographic coronary anatomy. FFR is the most well-established tool for functional assessment of coronary lesions. Randomized trials have demonstrated the benefit of FFR-guided percutaneous coronary intervention (PCI) to determine the ischemic burden of intermediate lesions. Surgically, FFR is predominantly used to determine the functional severity of intermediate lesions of the left anterior descending (LAD) coronary artery to establish candidacy for multivessel coronary bypass. The broader use of FFR will likely downgrade a proportion of coronary lesions, which may alter the overall management plan. Whether this will improve clinical outcomes remains to be seen. Importantly, bypass of functionally nonsignificant lesions predicts graft failure. However, graft failure in the context of sufficient native coronary flow may not impact negatively on clinical outcome. Thus, at this time, there are insufficient data to support the wider use of FFR to guide surgical grafting of non-LAD targets. It remains to be seen whether FFR can be used to optimize the use of arterial grafts or to guide complex revascularization strategies such as hybrid coronary revascularization.

SUMMARY

FFR has become an invaluable tool for decision making for PCI in patients with stable ischemic heart disease. Beyond its use to assess an intermediate LAD lesion to establish candidacy for coronary bypass, at present there are insufficient data to support its wider use to guide surgical revascularization.

Fractional flow reserve to guide and to assess coronary artery bypass grafting

The aim of this review is to highlight the role of invasive functional evaluation in patients in whom coronary artery bypass graft (CABG) is indicated, and to examine the clinical evidence available in favour of fractional flow reserve (FFR) adoption in these patients, outline appropriate use, as well as point out potential pitfalls. FFR after CABG will also be reviewed, highlighting its correct interpretation and adoption when applied to both native coronary arteries and bypass grafts. Practice European guidelines support the use of FFR to complement coronary angiography with the highest degree of recommendation (Class IA) for the assessment of coronary stenosis before undertaking myocardial revascularization when previous non-invasive functional evaluation is unavailable or not conclusive. As a result, FFR has been adopted in routine clinical practice to guide clinicians decision as to whether or not perform a revascularization. Of note, due to the increasing confidence of the interventional cardiologists, FFR guidance is also being implemented to indicate or guide CABG. This is in anticipation of supportive clear-cut evidence, since recommendations for FFR adoption were based on randomized clinical trials investigating percutaneous coronary intervention (PCI) strategies in which patients with typical indications for CABG were excluded (e.g. left main disease, valvular disease, and coronary anatomy unsuitable for PCI). Based on the critical appraisal of the literature, FFR can play an important role in risk stratification and determining management strategy of patients either before or after CABG.

Correlation between Angiographic and Physiologic Evaluation of Coronary Artery Narrowings in Patients With Aortic Valve Stenosis

We aimed to assess the correlation between angiographic and physiologic evaluation of coronary lesions in aortic stenosis (AS) patients presenting with intermediate coronary stenoses at the angiography. From 2002 to 2010, we included 163 patients from 2 centers with both AS and coronary artery disease (CAD), matched by age and gender with 163 contemporary patients with CAD alone. With both quantitative coronary angiography and fractional flow reserve (FFR), we assessed 259 coronary stenoses in the AS + CAD group, and 256 in the CAD alone group. A significant correlation was found between diameter stenosis (DS) and FFR in both groups, although this was significantly stronger in the AS + CAD than in the CAD alone group (R = -0.63 vs -0.44, p <0.01). Likewise, the correlation between minimum lumen diameter and FFR was stronger in the AS + CAD than in the CAD alone group (R = -0.54 vs -0.41, p = 0.05). Receiver operator characteristic curves analysis showed that DS was a better predictor of hemodynamically significant coronary stenoses (FFR ≤0.8) in the AS + CAD rather than in the CAD alone group (area under the curve = 0.83 vs 0.67, p <0.01). With 50% DS cut-off value, the sensitivity, specificity, and accuracy was 77%, 66%, and 70% in the AS + CAD group versus 59%, 63%, and 61% in the CAD alone group. In both groups, the diagnostic accuracy of DS in predicting FFR was higher in the right and circumflex coronary artery compared with the left anterior descending artery (LAD), although this was only statistically significant in the AS + CAD group (area under the curve 0.88 in the right and circumflex coronary artery vs 0.76 in LAD, p = 0.03). In conclusion, the correlation between the angiographic and hemodynamic significance of coronary stenoses is modest in AS patients. The assessment of CAD severity solely based on angiography poorly predicts the hemodynamic significance of the coronary stenosis especially when these are located in the LAD.

Transcatheter Aortic Valve Implantation With or Without Percutaneous Coronary Artery Revascularization Strategy: A Systematic Review and Meta-Analysis

BACKGROUND

Recent recommendations suggest that in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation and coexistent significant coronary artery disease, the latter should be treated before the index procedure; however, the evidence basis for such an approach remains limited. We performed a systematic review and meta-analysis to study the clinical outcomes of patients with coronary artery disease who did or did not undergo revascularization prior to transcatheter aortic valve implantation.

METHODS AND RESULTS

We conducted a search of Medline and Embase to identify studies evaluating patients who underwent transcatheter aortic valve implantation with or without percutaneous coronary intervention. Random-effects meta-analyses with the inverse variance method were used to estimate the rate and risk of adverse outcomes. Nine studies involving 3858 participants were included in the meta-analysis. Patients who underwent revascularization with percutaneous coronary intervention had a higher rate of major vascular complications (odd ratio [OR]: 1.86; 95% confidence interval [CI], 1.33-2.60; P=0.0003) and higher 30-day mortality (OR: 1.42; 95% CI, 1.08-1.87; P=0.01). There were no differences in effect estimates for 30-day cardiovascular mortality (OR: 1.03; 95% CI, 0.35-2.99), myocardial infarction (OR: 0.86; 95% CI, 0.14-5.28), acute kidney injury (OR: 0.89; 95% CI, 0.42-1.88), stroke (OR: 1.07; 95% CI, 0.38-2.97), or 1-year mortality (OR: 1.05; 95% CI, 0.71-1.56). The timing of percutaneous coronary intervention (same setting versus a priori) did not negatively influence outcomes.

CONCLUSIONS

Our analysis suggests that revascularization before transcatheter aortic valve implantation confers no clinical advantage with respect to several patient-important clinical outcomes and may be associated with an increased risk of major vascular complications and 30-day mortality. In the absence of definitive evidence, careful evaluation of patients on an individual basis is of paramount importance to identify patients who might benefit from elective revascularization.

Fractional flow reserve to guide surgical coronary revascularization

Coronary angiography has traditionally been used as the final diagnostic tool in the evaluation of coronary artery disease (CAD). However, conventional angiography identifies anatomically obstructive coronary disease, but it is limited in its ability to identify hemodynamically significant lesions. The emergence of fractional flow reserve (FFR) technology, in conjunction with angiography, offers a functional, as well as anatomic, assessment of epicardial coronary obstructions. Several pivotal studies have demonstrated that FFR-guided coronary revascularization is a safe and effective in patients with single and multivessel CAD. There are emerging data to suggest that FFR may also play an integral role in planning surgical revascularization and in the evaluation of post-coronary artery bypass patients and their graft patency. This review will explore the physiologic underpinnings of FFR methodology, its clinical value and limitations, and its applications in coronary artery bypass grafting (CABG) surgery.

Practical Considerations of Fractional Flow Reserve Utilization to Guide Revascularization

OPINION STATEMENT

Invasive angiography has long been the gold standard for the diagnosis of obstructive coronary artery disease (CAD). However, the relationship between angiographic measures of stenosis and coronary blood flow is complex, and there is frequent discordance between the visual assessment of a stenotic lesion and its effect on myocardial perfusion. Fractional flow reserve is a rapidly emerging invasive means of assessing the physiologic significance of an epicardial stenosis. This review provides a pragmatic understanding of the physiologic principles that guide fractional flow reserve (FFR), sheds light on its nuances, and explores the most landmark investigations. We will also discuss how the measurement of FFR can be helpful or limiting in several common clinical situations.

Functional Assessment of Coronary Artery Disease in Patients Undergoing Transcatheter Aortic Valve Implantation

Background—

Aortic valve stenosis may influence fractional flow reserve (FFR) of concomitant coronary artery disease by causing hypertrophy and reducing the vasodilatory reserve of the coronary circulation. We sought to investigate whether FFR values might change after valve replacement.

Methods and Results—

The functional relevance of 133 coronary lesions was assessed by FFR in 54 patients with severe aortic valve stenosis before and after transcatheter aortic valve implantation (TAVI) during the same procedure. A linear mixed model was used to verify the interaction of TAVI effect with the FFR values. No significant overall change in FFR values was found before and after the aortic valve stenosis removal (0.89±0.10 versus 0.89±0.13; P =0.73). A different trend in FFR groups (positive if ≤0.8; negative if >0.8) was found after TAVI ( P for interaction <0.001). Positive FFR values worsened after TAVI (0.71±0.11 versus 0.66±0.14). Conversely, negative FFR values improved after TAVI (0.92±0.06 versus 0.93±0.07). Similarly, FFR values in coronary arteries with lesions presenting percent diameter stenosis >50 worsened after TAVI (0.84±0.12 versus 0.82±0.16; P =0.02), whereas FFR values in arteries with mild lesions (percent diameter stenosis <50) tended toward improvement after TAVI (0.90±0.07 versus 0.91±0.09; P =0.69). Functional FFR variations after TAVI changed the indication to treat the coronary stenosis in 8 of 133 (6%) lesions.

Conclusions—

Coronary hemodynamics are influenced by aortic valve stenosis removal. Nevertheless, FFR variations after TAVI are minor and crossed the diagnostic cutoff of 0.8 in a small number of patients after valve replacement. Borderline coronary lesions might become functionally significant after valve replacement, although FFR-guided interventions were infrequent even in patients with angiographically significant lesions.

[Measurement of fractional flow reserve in patients with severe aortic stenosis: A valid test?]

A 54-year-old woman was hospitalized for an acute pulmonary oedema revealing a severe aortic stenosis (AS) associated with an aortic aneurysm and a left ventricular hypertrophy (LVH). The coronary angiography found an equivocal left main lesion. Fractional flow reserve (FFR) showed hemodynamic significance (FFR=0.78) and optical coherence tomography confirmed this result with a minimal lumen area of 4.9mm². FFR-guided percutaneous intervention is reported to improve outcome in patients with stable coronary disease. However, only few data are available in cases of AS. In this condition, secondary LVH is associated with microcirculatory dysfunction, which interferes with optimal hyperemia. An elevated right atrial pressure could also modify FFR measurement. This risk of underestimation of a coronary lesion in patients with severe AS has to be taken into consideration in clinical practice.