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

A randomised multicentre study of angiography- versus physiologyguided percutaneous coronary intervention in patients with coronary artery disease undergoing TAVI: design and rationale of the FAITAVI trial

The treatment of coronary artery disease (CAD) in patients with severe aortic valve stenosis (AVS) eligible for transcatheter aortic valve implantation (TAVI) is not supported by clinical evidence, and the role of physiology over anatomy as well as the timing of coronary intervention are not defined. FAITAVI (ClinicalTrials.gov: NCT03360591) is a nationwide prospective, open-label, multicentre, randomised controlled study comparing the angiography-guided versus the physiology-guided coronary revascularisation strategy in patients with combined significant CAD and severe AVS undergoing TAVI. Significant CAD will be defined as coronary stenosis ≥50%, as assessed by visual estimation in vessels ≥2.5 mm. Physiology will be tested by fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR). The study will be conducted at 15 sites in Italy. In the angiography arm, percutaneous coronary intervention (PCI) will be performed either before TAVI, during the TAVI procedure - before or after the valve implantation - or within 1 month±5 days of the valve implantation, left to the operator's decision. In the physiology arm, FFR and iFR will be performed before TAVI, and PCI will be indicated for FFR ≤0.80, otherwise the intervention will be deferred. In case of borderline values (0.81-0.85), FFR and iFR will be repeated after TAVI, with PCI performed when needed. With a sample size of 320 patients, the study is powered to evaluate the primary endpoint (a composite of death, myocardial infarction, stroke, major bleeding, or ischaemia-driven target vessel revascularisation). TAVI indication, strategy and medical treatment will be the same in both groups. After discharge, patients will be contacted at 1, 6, 12 and 24 months after the procedure to assess their general clinical status, and at 12 months for the occurrence of events included in the primary and secondary endpoints. FAITAVI is the first randomised clinical trial to investigate "optimal" percutaneous coronary intervention associated with TAVI in patients with severe AVS and CAD.

Fractional Flow Reserve to Assess Coronary Artery Disease in Patients with Severe Aortic Stenosis Undergoing Transcatheter Aortic Valve Implantation: Long-Term Outcomes

Background

The long-term outcomes of patients undergoing functional assessment of coronary lesions with fractional flow reserve (FFR) while awaiting transcatheter aortic valve implantation (TAVI) are unknown. Data on the safety of intracoronary adenosine use in this setting are scarce. The objectives of this study were to describe (1) the long-term outcomes based on the coronary artery disease (CAD) assessment strategy used and (2) the safety of intracoronary adenosine in patients with severe aortic stenosis (AS).

Methods

1023 patients with severe AS awaiting TAVI were included. Patients were classified according to their CAD assessment strategy: angiography guided or FFR guided. Patients were further subdivided according to the decision to proceed with percutaneous coronary intervention (PCI): angiography-guided PCI (375/1023), angiography-guided no-PCI (549/1023), FFR-guided PCI (50/1023), and FFR-guided no-PCI (49/1023). Patients were followed up for the occurrence of major adverse cardiac and cerebrovascular events (MACCEs).

Results

At a mean follow-up of 33.7 months, we observed no significant differences in terms of major adverse cardiovascular and cerebrovascular events (MACCE) in the angiography-guided group (42.4%) compared with the FFR-guided group (37.4%) (p = 0.333). When comparing outcomes of the FFR-guided no-PCI group (32.7%) with the angiography-guided PCI group (46.4%), no significant difference was noted (p = 0.999). Following intracoronary adenosine, a single adverse event occurred.

Conclusions

In this population, intracoronary adenosine is safe and well tolerated. We found no significant benefit to an FFR-guided strategy compared with an angiography-guided strategy with respect to MACCEs. Although clinically compelling, avoiding the procedural risks of PCI by deferring the intervention in functionally insignificant lesions failed to show a statistically significant benefit.

Absolute coronary flow and microvascular resistance reserve in patients with severe aortic stenosis

BACKGROUND

Development of left ventricle (LV) hypertrophy in aortic stenosis (AS) is accompanied by adaptive coronary flow regulation. We aimed to assess absolute coronary flow, microvascular resistance, coronary flow reverse (CFR) and microvascular resistance reserve (MRR) in patients with and without AS.

METHODS

Absolute coronary flow and microvascular resistance were measured by continuous thermodilution in 29 patients with AS and 29 controls, without AS, matched for age, gender, diabetes and functional severity of epicardial coronary lesions. Myocardial work, total myocardial mass and left anterior descending artery (LAD)-specific mass were quantified by echocardiography and cardiac-CT.

RESULTS

Patients with AS presented a significantly positive LV remodelling with lower global longitudinal strain and global work efficacy compared with controls. Total LV myocardial mass and LAD-specific myocardial mass were significantly higher in patients with AS (p=0.001). Compared with matched controls, absolute resting flow in the LAD was significantly higher in the AS cohort (p=0.009), resulting into lower CFR and MRR in the AS cohort compared with controls (p<0.005 for both). No differences were found in hyperaemic flow and resting and hyperaemic resistances. Hyperaemic myocardial perfusion (calculated as the ratio between the absolute coronary flow subtended to the LAD, expressed in mL/min/g), but not resting, was significantly lower in the AS group (p=0.035).

CONCLUSIONS

In patients with severe AS and non-obstructive coronary artery disease, with the progression of LV hypertrophy, the compensatory mechanism of increased resting flow maintains adequate perfusion at rest, but not during hyperaemia. As a consequence, both CFR and MRR are significantly impaired.

Myocardial Perfusion and Coronary Physiology Assessment of Microvascular Dysfunction in Patients Undergoing Transcatheter Aortic Valve Implantation-Rationale and Design

The prevalence of coronary artery disease (CAD) in patients with severe aortic stenosis (AS) is 30-68%. Nevertheless, there is still not enough evidence to use invasive assessment of lesion severity, because the hemodynamic milieu of AS may impact the fractional flow reserve (FFR) and non-hyperemic indices. Therefore, the aim of the study is two-fold. First, to measure acute and long-term changes of FFR, index of microvascular resistance (IMR), and coronary flow reserve (CFR) in patients undergoing TAVI procedure. Second, to compare the diagnostic accuracy of intracoronary indices with myocardial perfusion measured by cadmium-zinc-telluride single-photon emission tomography (CZT-SPECT) and find cut-off values defining significant stenosis. We plan to enroll 40 patients eligible for TAVI with intermediate stenosis (30-70%) in the left anterior descending (LAD) coronary artery. In each patient FFR, CFR, and IMR will be measured in addition to myocardial blood flow calculated by CZT-SPECT before and either immediately after TAVI (acute cohort) or in 6 months (late cohort) after the procedure. FFR, CFR, and IMR will be matched with the results of myocardial perfusion measured by CZT-SPECT in the area of LAD. As a result, cut-off values of FFR, CFR, and IMR defining the decreased blood flow will be found.

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.

Insulin Resistance Predicts Severity of Coronary Atherosclerotic Disease in Non-Diabetic Patients

Background: Insulin resistance (IR) in patients with type 2 diabetes mellitus (T2DM) represents a predictor of coronary artery disease (CAD). However, how IR is able to impact the severity of coronary atherosclerosis in non-diabetic patients is unknown. Objectives. We investigated the relation between the IR and the extent and severity of coronary atherosclerosis in non-diabetic patients referred to coronary angiography (CA) Methods: Consecutive patients undergoing to CA for acute coronary syndromes or stable angina were analyzed. The IR was assessed by mean of the homeostasis model assessment of insulin resistance (HOMA-IR) whereas the SYNTAX score (SS) was used as index of the severity of coronary atherosclerosis Results: Overall, 126 patients were included, with a median SS of 12 (IQR 5.25–20.5). Patients were divided in four groups according to the distribution in quartiles of SS (SS1-2-3-4). A significant correlation between HOMA-IR and SS was observed, especially in women. A progressive increase of HOMA-IR was observed in parallel with the increasing severity (from SS1 to SS4) and extension (1-2-3-vessel disease) of coronary atherosclerosis. Multivariable analysis showed that the HOMA-IR was the strongest independent predictor of severe (SS4) and extensive (three-vessel disease) coronary atherosclerosis. Conclusion: Insulin resistance goes hand in hand with the extension and severity of coronary atherosclerosis in non-diabetic patients. The HOMA index is an independent predictor of three-vessel disease at CA. The HOMA index could be useful for risk stratification of CAD even in absence of T2DM.

Physiological Versus Angiographic Guidance for Myocardial Revascularization in Patients Undergoing Transcatheter Aortic Valve Implantation

Background Management of coronary artery disease in patients undergoing transcatheter aortic valve implantation is uncertain. Fractional flow reserve (FFR) has never been clinically validated in aortic stenosis. The study aim was to analyze the clinical outcome of FFR-guided revascularization in patients undergoing transcatheter aortic valve implantation. Methods and Results Patients with severe aortic stenosis and coronary artery disease at coronary angiography were included in this retrospective analysis and divided in 2 groups: angiography guided (122/216; 56.5%) versus FFR-guided revascularization (94/216; 43.5%). Patients were clinically followed up and evaluated for the occurrence of major adverse cardiac and cerebrovascular events at 2-year follow-up. Most lesions in the FFR group resulted negative according to the conventional 0.80 cutoff value (111/142; 78.2%) and were deferred. The FFR-guided group showed a better major adverse cardiac and cerebrovascular event-free survival compared with the angio-guided group (92.6% versus 82.0%; hazard ratio, 0.4; 95% CI, 0.2-1.0; P=0.035). Patients with deferred lesions based on FFR presented better outcome compared with patients who underwent angio-guided percutaneous coronary intervention (91.4% versus 68.1%; hazard ratio, 0.3; 95% CI, 0.1-0.6; P=0.001). Conclusions FFR guidance was associated with favorable outcome in this observational study in patients undergoing transcatheter aortic valve implantation. Randomized trials are needed to investigate the long-term effects of FFR-guided revascularization against angiographic guidance alone in patients with aortic stenosis.

Severity of Coronary Atherosclerosis and Risk of Diabetes Mellitus

Background: Cardio-vascular target organ damage predicts the onset of type 2 diabetes mellitus (DM) in hypertensive patients. Whether an increased incidence of DM is also in relation to the severity of coronary atherosclerosis is unknown. Objective: We evaluated the onset of DM in relation to the extent and severity of coronary atherosclerosis, using the SYNTAX (Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) score (SS), in patients with stable angina or acute coronary syndromes, referred for coronary angiography (CA). Methods: Non-diabetic patients that underwent CA for the first time were included, and the SS was computed. Predictors of DM onset in low, medium, and high SSs were investigated. Results: Five hundred and seventy patients were included, and the mean SS was 6.3 ± 7.6. During a median follow-up of 79 months (interquartile range (IQR): 67–94), 74 patients (13%) developed DM. The risk of DM onset was significantly higher in the patients with a medium or high SS (hazard ratio (HR)—95% confidence interval (CI): 16 (4–61), p < 0.0001; and 30 (9–105), p < 0.0001, vs low SS, respectively), even after adjustment for obesity, history of hypertension, impaired fasting glucose, and cardiovascular therapy. Conclusions: The severity and extent of the coronary atherosclerosis, evaluated by the SS, is a strong and independent predictor of the development of DM in patients, referred to CA.

Comparison of Outcomes After Transcatheter Aortic Valve Replacement vs Surgical Aortic Valve Replacement Among Patients With Aortic Stenosis at Low Operative Risk

IMPORTANCE

Transcatheter aortic valve replacement (TAVR) has been shown to be a valid alternative to surgical aortic valve replacement (SAVR) in patients at high operative risk with severe aortic stenosis (AS). However, the evidence of the benefits and harms of TAVR in patients at low operative risk is still scarce.

OBJECTIVE

To compare the short-term and midterm outcomes after TAVR and SAVR in low-risk patients with AS.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective comparative effectiveness cohort study used data from the Nationwide Finnish Registry of Transcatheter and Surgical Aortic Valve Replacement for Aortic Valve Stenosis of patients at low operative risk who underwent TAVR or SAVR with a bioprosthesis for severe AS from January 1, 2008, to November 30, 2017. Low operative risk was defined as a Society of Thoracic Surgeons Predicted Risk of Mortality score less than 3% without other comorbidities of clinical relevance. One-to-one propensity score matching was performed to adjust for baseline covariates between the TAVR and SAVR cohorts.

EXPOSURES

Primary TAVR or SAVR with a bioprosthesis for AS with or without associated coronary revascularization.

MAIN OUTCOMES AND MEASURES

The primary outcomes were 30-day and 3-year survival.

RESULTS

Overall, 2841 patients (mean [SD] age, 74.0 [6.2] years; 1560 [54.9%] men) fulfilled the inclusion criteria and were included in the analysis; TAVR was performed in 325 patients and SAVR in 2516 patients. Propensity score matching produced 304 pairs with similar baseline characteristics. Third-generation devices were used in 263 patients (86.5%) who underwent TAVR. Among these matched pairs, 30-day mortality was 1.3% after TAVR and 3.6% after SAVR (P = .12). Three-year survival was similar in the study cohorts (TAVR, 85.7%; SAVR, 87.7%; P = .45). Interaction tests found no differences in terms of 3-year survival between the study cohorts in patients younger than vs older than 80 years or in patients who received recent aortic valve prostheses vs those who did not.

CONCLUSIONS AND RELEVANCE

Transcatheter aortic valve replacement using mostly third-generation devices achieved similar short- and mid-term survival compared with SAVR in low-risk patients. Further studies are needed to assess the long-term durability of TAVR prostheses before extending their use to low-risk patients.

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.

Fractional flow reserve (FFR) as a guide to treat coronary artery disease

INTRODUCTION

The presence and extent of myocardial ischemia are the major determinants of prognosis in patients with coronary artery disease (CAD). Unlike coronary angiography alone, fractional flow reserve (FFR) has enabled interventional cardiologists to accurately determine whether coronary atherosclerotic plaques are responsible for myocardial ischemia, and therefore deserve to be revascularized. Areas covered: An overview on the role of FFR in the diagnosis and treatment of coronary artery disease, as well as the potential related controversies is provided. Authors describe the coronary physiology underneath this technique and all the procedural aspects in the catheterization laboratory. The landmark trials and the current applications in different coronary lesions and syndromes are also described and potential future research involving FFR and comparisons with other methodologies for the evaluation of coronary physiology are introduced. Expert commentary: FFR is still unsurpassed in diagnostic performance when compared to non-hyperemic indices and noninvasive techniques, and remains the gold standard for the detection of ischemia-inducing coronary stenoses. FFR-guided PCI has been demonstrated superior to an angiography-guided PCI and over medical therapy alone, and ongoing investigation will clarify whether it could perform better, or at least equalize the results of cardiac surgery in patients with severe multivessel disease.