Aortic valve replacement versus conservative treatment in asymptomatic severe aortic stenosis: long-term follow-up of the AVATAR trial.

BACKGROUND AND AIMS: The question of when and how to treat truly asymptomatic patients with severe aortic stenosis (AS) and normal left ventricular (LV) systolic function is still subject to debate and ongoing research. Here, the results of extended follow-up of the AVATAR trial are reported (NCT02436655, clinical trials.gov). METHODS: The AVATAR trial randomly assigned patients with severe, asymptomatic AS and LV ejection fraction ≥50% to undergo either early surgical aortic valve replacement (AVR) or conservative treatment with watchful waiting strategy. All patients had negative exercise stress testing. The primary hypothesis was that early AVR will reduce a primary composite endpoint comprising all-cause death, acute myocardial infarction, stroke or unplanned hospitalization for heart failure (HF), as compared to conservative treatment strategy. RESULTS: A total of 157 low-risk patients (mean age 67 years, 57% men, mean Society of Thoracic Surgeons score 1.7%) were randomly allocated to either early AVR group (n=78) or conservative treatment group (n=79). In an intention-to-treat analysis, after a median follow-up of 63 months, the primary composite endpoint outcome event occurred in 18/78 patients (23.1%) in the early surgery group and in 37/79 patients (46.8%) in the conservative treatment group (hazard ratio [HR] early surgery vs. conservative treatment 0.42; 95% confidence interval [CI] 0.24-0.73, p=0.002). The Kaplan-Meier estimates for individual endpoints of all-cause death and HF hospitalization were significantly lower in the early surgery compared with the conservative group (HR 0.44; 95% CI 0.23-0.85, p=0.012 for all-cause death, and HR 0.21; 95% CI 0.06-0.73, p=0.007 for HF hospitalizations). CONCLUSIONS: The extended follow-up of the AVATAR trial demonstrates better clinical outcomes with early surgical AVR in truly asymptomatic patients with severe AS and normal LV ejection fraction compared with patients treated with conservative management on watchful waiting. TRIAL REGISTRATION NUMBER: NCT02436655 (ClinicalTrials.gov).

Incidence and Prognostic Significance of Silent Coronary Disease in Asymptomatic Patients with Severe Aortic Stenosis.

Background and Objectives: The aim of this study was to estimate the prevalence of silent coronary artery disease (CAD) in asymptomatic patients with severe aortic stenosis (AS) and assess long-term prognosis in terms of major adverse cardiovascular event (MACE)-free survival. Materials and Methods: This was a prospective study conducted at the Clinic for Cardiac Surgery, University Clinical Center of Serbia, in asymptomatic patients with severe AS, normal LVEF and stress test without signs of myocardial ischemia. Adverse cardiovascular events (cardiac death, myocardial infarction and any hospitalization due to heart disease) was monitored during one year of follow up. Results: A total of 116 asymptomatic patients with severe AS were included in the study. The average age was 67.3 ± 9.6 years, and 56.9% of patients were men. The most common cause of AS was degenerative valvular disease (83.5%). The incidence of significant CAD was 30 out of 116 patients (25.9%). The median Society for Thoracic Surgeons (STS) predicted risk of mortality score was 1.62% (25th to 75th percentile: 1.15-2.76%). The overall mean gradient across aortic valve (Pmean) was 52.30 mmHg ± 12.16, and the mean indexed AVA (AVAi) was 0.37 ± 0.09 cm2/m2. The mean LVEF was 68.40% ± 8.01%. Early surgery for aortic valve replacement was performed in 55 patients (55.2%), while 52 (44.8%) patients received conservative treatment. Twenty-two patients (42.3%) in the conservative treatment group underwent surgery during follow up. There were a total of 44 (37.9%) patients with MACE during one year of follow up. Univariate Cox regression analyses identified the following significant risk factors for MACE-free survival: presence of CAD and early conservative treatment (p = 0.004), age (p = 0.003), diabetes mellitus (p = 0.016) and STS score (p = 0.039). According to multivariate analysis, the presence of CAD with early conservative treatment was the most important predictor of MACE-free survival in asymptomatic patients with severe aortic stenosis (p ≤ 0.001). Conclusions: Early surgery for aortic valve replacement in asymptomatic patients with severe AS and concomitant CAD is beneficial for long-term survival.

Asymptomatic Aortic Stenosis: From Risk Stratification to Treatment.

Our understanding of the natural history of aortic stenosis has significantly increased over the last decade. There have been considerable advances in the diagnosis and risk stratification of patients with aortic stenosis and in surgical and anesthetic techniques. In addition, transcatheter aortic valve replacement has established itself as a viable alternative to surgical management. Inevitably, these developments have raised questions regarding the merits of waiting for symptom onset in asymptomatic patients with severe aortic stenosis before offering treatment. Recent observational and randomized trial data suggest that early intervention in asymptomatic patients with severe aortic stenosis and normal left ventricular function may confer a prognostic advantage to a watchful waiting strategy. In this review, we highlight advances in the management and risk stratification of patients with asymptomatic severe aortic stenosis with particular consideration of recent findings supporting early valvular intervention.

Acute Coronary Syndrome Following Transcatheter Aortic Valve Replacement.

Extending the indication of transcatheter aortic valve replacement (TAVR) to younger and lower-risk patients naturally results in longer life expectancy and survival rates after the intervention. The longer life expectancy of these patients leads to an increased possibility of future acute coronary events, necessitating the development of effective and appropriate treatment strategies. Acute coronary syndromes (ACS) in patients with previous TAVR procedures present with modified clinical characteristics when compared to the non-TAVR population. In populations with prior TAVR procedures, plaque rupture remains the main cause of ACS. However, unlike the non-TAVR population, there is an increased frequency of nonatherotrombotic mechanisms, like emboli and mechanical obstruction of coronary ostia by valve components. The main observation related to the treatment of ACS TAVR patients is the significantly lower percentage of patients undergoing invasive management. Furthermore, ACS in TAVR patients is associated with poor prognosis, higher long-term mortality rates, and higher incidence of MACE. It is surprising that considering this significant and increasingly recognized issue, there are only a few studies that have investigated ACS after TAVR. The scope of the present review is to address available data about ACS following TAVR, focusing on incidence, timing, mechanism, and causes. We also examined current knowledge regarding optimal invasive treatment and analyzed short and long-term clinical outcomes.

Asymptomatic Severe and Moderate Aortic Stenosis: Time for Appraisal of Treatment Indications.

Over the last decades, we have witnessed considerable improvements in diagnostics and risk stratification of patients with significant aortic stenosis (AS), paralleled by advances in operative and anesthetic techniques. In addition, accumulating evidence points to the potential benefit of early valve replacement in such patients prior to the onset of symptoms. In parallel, interventional randomized trials have proven the benefit of transcatheter aortic valve replacement in comparison to a surgical approach to valve replacement over a broad risk spectrum in symptomatic patients with AS. This article reviews contemporary management approaches and scrutinizes open questions regarding timing and mode of intervention in asymptomatic patients with severe AS. We also discuss the challenges surrounding the management of symptomatic patients with moderate AS as well as emerging dilemmas related to the concept of a life-long treatment strategy for patients with AS.

Impact of diabetes on remodelling, microvascular function and exercise capacity in aortic stenosis.

OBJECTIVE: To characterise cardiac remodelling, exercise capacity and fibroinflammatory biomarkers in patients with aortic stenosis (AS) with and without diabetes, and assess the impact of diabetes on outcomes. METHODS: Patients with moderate or severe AS with and without diabetes underwent echocardiography, stress cardiovascular magnetic resonance (CMR), cardiopulmonary exercise testing and plasma biomarker analysis. Primary endpoint for survival analysis was a composite of cardiovascular mortality, myocardial infarction, hospitalisation with heart failure, syncope or arrhythmia. Secondary endpoint was all-cause death. RESULTS: Diabetes (n=56) and non-diabetes groups (n=198) were well matched for age, sex, ethnicity, blood pressure and severity of AS. The diabetes group had higher body mass index, lower estimated glomerular filtration rate and higher rates of hypertension, hyperlipidaemia and symptoms of AS. Biventricular volumes and systolic function were similar, but the diabetes group had higher extracellular volume fraction (25.9%±3.1% vs 24.8%±2.4%, p=0.020), lower myocardial perfusion reserve (2.02±0.75 vs 2.34±0.68, p=0.046) and lower percentage predicted peak oxygen consumption (68%±21% vs 77%±17%, p=0.002) compared with the non-diabetes group. Higher levels of renin (log10renin: 3.27±0.59 vs 2.82±0.69 pg/mL, p<0.001) were found in diabetes. Multivariable Cox regression analysis showed diabetes was not associated with cardiovascular outcomes, but was independently associated with all-cause mortality (HR 2.04, 95% CI 1.05 to 4.00; p=0.037). CONCLUSIONS: In patients with moderate-to-severe AS, diabetes is associated with reduced exercise capacity, increased diffuse myocardial fibrosis and microvascular dysfunction, but not cardiovascular events despite a small increase in mortality.

Contemporary Challenges of Regenerative Therapy in Patients with Ischemic and Non-Ischemic Heart Failure.

It has now been almost 20 years since first clinical trials of stem cell therapy for heart repair were initiated. While initial preclinical data were promising and suggested that stem cells may be able to directly restore a diseased myocardium, this was never unequivocally confirmed in the clinical setting. Clinical trials of cell therapy did show the process to be feasible and safe. However, the clinical benefits of this treatment modality in patients with ischemic and non-ischemic heart failure have not been consistently confirmed. What is more, in the rapidly developing field of stem cell therapy in patients with heart failure, relevant questions regarding clinical trials' protocol streamlining, optimal patient selection, stem cell type and dose, and the mode of cell delivery remain largely unanswered. Recently, novel approaches to myocardial regeneration, including the use of pluripotent and allogeneic stem cells and cell-free therapeutic approaches, have been proposed. Thus, in this review, we aim to outline current knowledge and highlight contemporary challenges and dilemmas in clinical aspects of stem cell and regenerative therapy in patients with chronic ischemic and non-ischemic heart failure.

Do all patients with asymptomatic severe aortic stenosis need treatment?

INTRODUCTION: Although guidelines recommend a watchful waiting strategy for patients with asymptomatic severe aortic stenosis, there have been considerable advancements in surgical and anesthetic techniques along with the success of transcatheter aortic valve replacement (AVR) as a viable alternative to surgical AVR. Inevitably, these developments have raised questions as to whether or not there is still merit in waiting for symptoms to ensue before treatment may be offered to these patients. AREA COVERED: The principal purpose of this paper is to review the data supporting earlier intervention in patients with asymptomatic severe aortic stenosis, and to project the implications these and other ongoing trials will have on indications for AVR in asymptomatic patients in the future. EXPERT OPINION: The threshold for intervention in certain subgroups of asymptomatic patients with severe AS has already been lowered. The next frontier will inevitably be determining whether all patients with severe AS should undergo AVR irrespective of their symptomatic status.

Challenges in Diagnosis and Functional Assessment of Coronary Artery Disease in Patients With Severe Aortic Stenosis.

More than half of patients with severe aortic stenosis (AS) over 70 years old have coronary artery disease (CAD). Exertional angina is often present in AS-patients, even in the absence of significant CAD, as a result of oxygen supply/demand mismatch and exercise-induced myocardial ischemia. Moreover, persistent myocardial ischemia leads to extensive myocardial fibrosis and subsequent coronary microvascular dysfunction (CMD) which is defined as reduced coronary vasodilatory capacity below ischemic threshold. Therefore, angina, as well as noninvasive stress tests, have a low specificity and positive predictive value (PPV) for the assessment of epicardial coronary stenosis severity in AS-patients. Moreover, in symptomatic patients with severe AS exercise testing is even contraindicated. Given the limitations of noninvasive stress tests, coronary angiography remains the standard examination for determining the presence and severity of CAD in AS-patients, although angiography alone has poor accuracy in the evaluation of its functional severity. To overcome this limitation, the well-established invasive indices for the assessment of coronary stenosis severity, such as fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR), are now in focus, especially in the contemporary era with the rapid increment of transcatheter aortic valve replacement (TAVR) for the treatment of AS-patients. TAVR induces an immediate decrease in hyperemic microcirculatory resistance and a concomitant increase in hyperemic flow velocity, whereas resting coronary hemodynamics remain unaltered. These findings suggest that FFR may underestimate coronary stenosis severity in AS-patients, whereas iFR as the non-hyperemic index is independent of the AS severity. However, because resting coronary hemodynamics do not improve immediately after TAVR, the coronary vasodilatory capacity in AS-patients treated by TAVR remain impaired, and thus the iFR may overestimate coronary stenosis severity in these patients. The optimal method for evaluating myocardial ischemia in patients with AS and co-existing CAD has not yet been fully established, and this important issue is under further investigation. This review is focused on challenges, limitations, and future perspectives in the functional assessment of coronary stenosis severity in these patients, bearing in mind the complexity of coronary physiology in the presence of this valvular heart disease.

Long-term follow-up of patients with chronic total coronary artery occlusion previously randomized to treatment with optimal drug therapy or percutaneous revascularization of chronic total occlusion (COMET-CTO).

Background: The COMET-CTO trial was a randomized prospective study that assessed long-term follow-up in patients with chronic total occlusion (CTO) in coronary arteries treated with percutaneous coronary intervention (PCI) or with optimal medical therapy (OMT). During the 9-month follow-up, the incidence of major adverse cardiac events (MACE) did not differ between the two groups; no death or myocardial infarction (MI) was observed. There was a significant difference in quality of life (QoL), assessed by the Seattle Angina Questionnaire (SAQ), in favor of the PCI group. Here we report long-term follow-up results (56 ± 12 months). Methods: Between October 2015 and May 2017, a total of 100 patients with CTO were randomized into two groups of 50 patients: PCI CTO or OMT group. The primary endpoint of the current study was the incidence of MACE defined as cardiac death, MI, and revascularization [PCI or coronary artery bypass graft (CABG)]. As the secondary exploratory outcome, we analyzed all the cause-mortality rate. Results: Out of 100 randomized patients, 92 were available for long-term follow-up (44 in the PCI group and 48 in the OMT group). The incidence of MACE did not differ significantly between the two groups (p = 0.363). Individual components of MACE were distributed, respectively: cardiac death (OMT vs. PCI group, 6 vs. 3, p = 0.489), MI (OMT vs. PCI group, 1 vs. 0, p = 1), and revascularization (PCI: OMT vs. PCI group, 2 vs. 2, p = 1; CABG: OMT vs. PCI group, 1 vs. 1, p = 1). There was no significant difference between the two groups regarding the individual component of MACE. Six patients died from non-cardiac causes [five deaths were reported in the OMT group and one death in the PCI group (p = 0.206)]. Kaplan-Meier survival curves for MACE did not differ significantly between the study groups (log-rank 0.804, p = 0.370). Regarding the secondary exploratory outcome, a total of 15 patients died at 56 ± 12 months (11 in the OMT and 4 in the PCI group) (p = 0.093). The Kaplan-Meier survival curves for all-cause mortality rates did not differ significantly between the two groups (log rank 3.404, p = 0.065). There were no statistically significant differences between OMT and PCI groups in all five SAQ domains. There was a significant improvement in three SAQ domains in the PCI group: PL (p < 0.001), AF (p = 0.007), and QoL (p = 0.001). Conclusion: After 56 ± 12 months of follow-up, the incidence of MACE, as well as QoL measured by SAQ, did not differ significantly between the PCI and OMT groups.

Aortic Valve Replacement Versus Conservative Treatment in Asymptomatic Severe Aortic Stenosis: The AVATAR Trial.

BACKGROUND: Surgical aortic valve replacement (SAVR) represents a class I indication in symptomatic patients with severe aortic stenosis (AS). However, indications for early SAVR in asymptomatic patients with severe AS and normal left ventricular function remain debated. METHODS: The AVATAR trial (Aortic Valve Replacement Versus Conservative Treatment in Asymptomatic Severe Aortic Stenosis) is an investigator-initiated international prospective randomized controlled trial that evaluated the safety and efficacy of early SAVR in the treatment of asymptomatic patients with severe AS, according to common criteria (valve area ≤1 cm2 with aortic jet velocity >4 m/s or a mean transaortic gradient ≥40 mm Hg), and with normal left ventricular function. Negative exercise testing was mandatory for inclusion. The primary hypothesis was that early SAVR would reduce the primary composite end point of all-cause death, acute myocardial infarction, stroke, or unplanned hospitalization for heart failure compared with a conservative strategy according to guidelines. The trial was designed as event-driven to reach a minimum of 35 prespecified events. The study was performed in 9 centers in 7 European countries. RESULTS: Between June 2015 and September 2020, 157 patients (mean age, 67 years; 57% men) were randomly allocated to early surgery (n=78) or conservative treatment (n=79). Follow-up was completed in May 2021. Overall median follow-up was 32 months: 28 months in the early surgery group and 35 months in the conservative treatment group. There was a total of 39 events, 13 in early surgery and 26 in the conservative treatment group. In the early surgery group, 72 patients (92.3%) underwent SAVR with operative mortality of 1.4%. In an intention-to-treat analysis, patients randomized to early surgery had a significantly lower incidence of primary composite end point than those in the conservative arm (hazard ratio, 0.46 [95% CI, 0.23-0.90]; P=0.02). There was no statistical difference in secondary end points, including all-cause mortality, first heart failure hospitalizations, major bleeding, or thromboembolic complications, but trends were consistent with the primary outcome. CONCLUSIONS: In asymptomatic patients with severe AS, early surgery reduced a primary composite of all-cause death, acute myocardial infarction, stroke, or unplanned hospitalization for heart failure compared with conservative treatment. This randomized trial provides preliminary support for early SAVR once AS becomes severe, regardless of symptoms. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02436655.

Functional Assessment of Myocardial Bridging With Conventional and Diastolic Fractional Flow Reserve: Vasodilator Versus Inotropic Provocation.

Background Functional assessment of myocardial bridging (MB) remains clinically challenging because of the dynamic nature of the extravascular coronary compression with a certain degree of intraluminal coronary reduction. The aim of our study was to assess performance and diagnostic value of diastolic-fractional flow reserve (d-FFR) during dobutamine provocation versus conventional-FFR during adenosine provocation with exercise-induced myocardial ischemia as reference. Methods and Results This prospective study includes 60 symptomatic patients (45 men, mean age 57±9 years) with MB on the left anterior descending artery and systolic compression ≥50% diameter stenosis. Patients were evaluated by exercise stress-echocardiography test, and both conventional-FFR and d-FFR in the distal segment of left anterior descending artery during intravenous infusion of adenosine (140 µg/kg per minute) and dobutamine (10-50 µg/kg per minute), separately. Exercise-stress-echocardiography test was positive for myocardial ischemia in 19/60 patients (32%). Conventional-FFR during adenosine and peak dobutamine had similar values (0.84±0.04 versus 0.84±0.06, P=0.852), but d-FFR during peak dobutamine was significantly lower than d-FFR during adenosine (0.76±0.08 versus 0.79±0.08, P=0.018). Diastolic-FFR during peak dobutamine was significantly lower in the exercise-stress-echocardiography test -positive group compared with the exercise- stress-echocardiography test -negative group (0.70±0.07 versus 0.79±0.06, P<0.001), but not during adenosine (0.79±0.07 versus 0.78±0.09, P=0.613). Among physiological indices, d-FFR during peak dobutamine was the only independent predictor of functionally significant MB (odds ratio, 0.870; 95% CI, 0.767-0.986, P=0.03). Receiver-operating characteristics curve analysis identifies the optimal d-FFR during peak dobutamine cut-off ≤0.76 (area under curve, 0.927; 95% CI, 0.833-1.000; P<0.001) with a sensitivity, specificity, and positive and negative predictive value of 95%, 95%, 90%, and 98%, respectively, for identifying MB associated with stress-induced ischemia. Conclusions Diastolic-FFR, but not conventional-FFR, during inotropic stimulation with high-dose dobutamine, in comparison to vasodilatation with adenosine, provides more reliable functional significance of MB in relation to stress-induced myocardial ischemia.

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.

Improvement of Maximal Exercise Performance After Catheter-Ablation of Atrial Fibrillation and Its Prognostic Significance for Long-Term Rhythm Outcome.

Background Rhythm control may improve functional capacity in patients with atrial fibrillation (AF). Long-term exercise tolerance improvement and its prognostic implications following catheter-ablation (CA) of paroxysmal and nonparoxysmal AF are underreported. Methods and Results Consecutive patients underwent cardiopulmonary exercise testing just before and 12 months after their index CA of AF. Follow-up 24-hour Holter recordings were obtained at 6-month intervals post-CA, and any atrial arrhythmia >30 seconds detected after 3 months postprocedure was considered AF recurrence. Of 110 patients (mean age 57.5±10.6 years, 77.2% males) with paroxysmal AF (n=66) or nonparoxysmal AF (n=44), the 12-month exercise tolerance improved significantly in those who maintained sinus rhythm during the first 12 months post-CA (n=96), but not in patients with AF recurrence (n=14). After CA, the 12-month respiratory exchange ratio at maximal workload significantly increased in patients with paroxysmal AF, whereas those with nonparoxysmal AF significantly reduced their heart rate during the 12-month cardiopulmonary exercise testing (all P≤0.001). During the follow-up of 42.8±7.8 months, a total of 29 patients (26.3%) experienced recurrent AF. On multivariate analysis including patients without recurrent AF at 12 months after CA, the extent of work time improvement at follow-up cardiopulmonary exercise testing was independently associated with the rhythm outcome beyond 12 months postprocedure (hazard ratio of 0.936 [95% CI, 0.894-0.979] for each 10 seconds increase in the work time following ablation, P=0.004). Conclusions CA of AF was associated with recovery of exercise intolerance in patients with paroxysmal AF or nonparoxysmal AF. Inability to improve exercise capacity at 12 months post-CA was an independent risk factor for later AF recurrence.