Coronary artery disease and transcatheter aortic valve replacement: current treatment paradigms

Histologically Validated Myocardial Fibrosis in Relation to Left Ventricular Geometry and Its Function in Aortic Stenosis

Background and Objectives: The combination of aortic valve stenosis (AS) and ischemic heart disease (IHD) is quite common and is associated with myocardial fibrosis (MF). The purpose of this study was to evaluate the association between the histologically verified left ventricular (LV) MF and its geometry and function in isolated AS and AS within IHD groups. Materials and Methods: In a single-center, prospective trial, 116 patients underwent aortic valve replacement (AVR) with/without concomitant surgery. The study population was divided into groups of isolated AS with/without IHD. Echocardiography was used, and LV measurements and aortic valve parameters were obtained from all patients. Myocardial tissue was procured from all study patients undergoing elective surgery. Results: There were no statistical differences between isolated AS and AS+IHD groups in LV parameters or systolic and diastolic functions during the study periods. The collagen volume fraction was significantly different between the isolated AS and AS+IHD groups and was 7.3 ± 5.6 and 8.3 ± 6.4, respectively. Correlations between MF and left ventricular end-diastolic diameter (LVEDD) (r = 0.59, p = < 0.001), left ventricular mass (LVM) (r = 0.42, p = 0.011), left ventricular ejection fraction (LVEF) (r = -0.67, p < 0.001) and an efficient orifice area (EOA) (r = 0.371, p = 0.028) were detected in isolated AS during the preoperative period; the same was observed for LVEDD (r = 0.45, p = 0.002), LVM (r = 0.36, p = 0.026), LVEF (r = -0.35, p = 0.026) and aortic annulus (r = 0.43, p = 0.018) in the early postoperative period; and LVEDD (r = 0.35, p ≤ 0.05), LVM (r = 0.43, p = 0.007) and EOA (r = 0.496, p = 0.003) in the follow-up period. In the group of AS and IHD, correlations were found only with LV posterior wall thickness (r = 0.322, p = 0.022) in the follow-up period. Conclusions: Histological MF in AS was correlated with LVM and LVEDD in all study periods. No correlations between MF and LV parameters were found in aortic stenosis in the ischemic heart disease group across all study periods.

TAVR Interventions and Coronary Access: How to Prevent Coronary Occlusion

Due to technological advancements during the past 20 years, transcatheter aortic valve replacements (TAVRs) have significantly improved the treatment of symptomatic and severe aortic stenosis, significantly improving patient outcomes. The continuous evolution of transcatheter valve models, refined imaging planning for enhanced accuracy, and the growing expertise of technicians have collectively contributed to increased safety and procedural success over time. These notable advancements have expanded the scope of TAVR to include patients with lower risk profiles as it has consistently demonstrated more favorable outcomes than surgical aortic valve replacement (SAVR). As the field progresses, coronary angiography is anticipated to become increasingly prevalent among patients who have previously undergone TAVR, particularly in younger cohorts. It is worth noting that aortic stenosis is often associated with coronary artery disease. While the task of re-accessing coronary artery access following TAVR is challenging, it is generally feasible. In the context of valve-in-valve procedures, several crucial factors must be carefully considered to optimize coronary re-access. To obtain successful coronary re-access, it is essential to align the prosthesis with the native coronary ostia. As part of preventive measures, strategies have been developed to safeguard against coronary obstruction during TAVR. One such approach involves placing wires and non-deployed coronary balloons or scaffolds inside an at-risk coronary artery, a procedure known as chimney stenting. Additionally, the bioprosthetic or native aortic scallops intentional laceration to prevent iatrogenic coronary artery obstruction (BASILICA) procedure offers an effective and safer alternative to prevent coronary artery obstructions. The key objective of our study was to evaluate the techniques and procedures employed to achieve commissural alignment in TAVR, as well as to assess the efficacy and measure the impact on coronary re-access in valve-in-valve procedures.

Transcatheter Aortic Valve Replacement in Elderly Patients: Opportunities and Challenges

Over the past two decades, the rapid evolution of transcatheter aortic valve replacement (TAVR) has revolutionized the management of severe aortic stenosis (AS) in the elderly. The prevalence of comorbidities in elderly AS patients presents a considerable challenge to the effectiveness and prognosis of patients after TAVR. In this article, we aim to summarize some of the clinical aspects of the current use of TAVR in elderly patients and attempt to highlight the challenges and issues that need further consideration.

Management of coronary artery disease in patients with aortic stenosis

Aortic stenosis (AS) is the most common valvular heart disorder in the elderly population. As a result of the shared pathophysiological processes, AS frequently coexists with coronary artery disease (CAD). These patients have traditionally been managed through surgical aortic valve replacement (SAVR) and coronary artery bypass grafting. However, increasing body of evidence supports transcatheter aortic valve implantation (TAVI) as an alternative treatment for severe AS across the spectrum of operative risk. This has created the potential for treating AS and concurrent CAD completely percutaneously. In this review we consider the evidence guiding the optimal management of patients with severe AS and CAD. While invasive coronary angiography plays a central role in detecting CAD in patients with AS undergoing surgery or TAVI, the benefits of complementary functional assessment of coronary stenosis in the context of AS have not been fully established. Although the indications for revascularisation of significant proximal CAD in SAVR patients have not recently changed, routine revascularisation of all significant CAD before TAVI in patients with minimal angina is not supported by the latest evidence. Several ongoing trials will provide new insights into physiology-guided revascularisation in TAVI recipients. The role of the heart team remains essential in this complex patient group, and if revascularisation is being considered careful evaluation of clinical, anatomical and procedural factors is essential for individualised decision-making.

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.

Routine CT angiography to detect severe coronary artery disease prior to transcatheter aortic valve replacement

Patients undergoing TAVR undergo routine CT angiography (CTA) to assess aorto-iliac pathology and annular dimensions. While coronary CTA may exclude severe CAD in younger patients, its efficacy in defining CAD severity prior to TAVR may be limited. We retrospectively studied 50 consecutive patients undergoing both invasive coronary angiography (ICA) and routine pre-TAVR CTA. Severe CAD was defined as ≥50% stenosis by quantitative coronary angiography and compared to a blinded CTA visual estimation of ≥50% stenosis. The analysis was confined to four segments: left main and three proximal to mid major coronaries to maximize myocardial territory at risk. Coronary assessment was performed using standard reconstructed ECG phases from pre-TAVR chest CTA on a Philips 256 iCT scanner. Nearly ¾ of patients were ≥75 years old, 57% were female, half were diabetic and 45% had prior PCI. By ICA, 49% had significant coronary calcification. The incidence of severe proximal to mid vessel CAD by ICA was 39%. Similarly, a third of patients required PCI prior to TAVR. CTA was unable to exclude severe proximal to mid vessel CAD in 88% of patients in all four segments: non-diagnostic CTA readings were mainly due to calcification (60%) or motion artifact (28%). Non-diagnostic coronary CTA readings ranged from 25 to 72% according to segment analyzed: only the left main segment had diagnostic quality CTA in the majority of patients (p < 0.01). PCI is performed frequently prior to TAVR based upon invasive coronary angiographic assessment. Routine chest CTA algorithms do not provide adequate diagnostic information to exclude severe CAD, primarily due to severe coronary calcification in the TAVR population.

Early Recovery of Left Ventricular Systolic Function After CoreValve Transcatheter Aortic Valve Replacement

BACKGROUND

Approximately one third of patients with symptomatic aortic stenosis have reduced left ventricular ejection fraction (LVEF) before transcatheter aortic valve replacement. The incidence, predictors, and significance of early LVEF recovery after CoreValve transcatheter aortic valve replacement have not been described.

METHODS AND RESULTS

We studied 156 patients from the CoreValve Extreme and High-Risk trials with LVEF ≤40% at baseline who had 30-day LVEF data. All patients underwent core laboratory echocardiographic assessment of LVEF at baseline, post procedure, discharge, 30 days, 6 months, and 1 year. Early LVEF recovery was defined as an absolute increase of ≥10% in EF at 30 days. One-year outcomes were compared between patients with and without early recovery. Multivariable analysis was performed to determine independent predictors of early recovery. Early LVEF recovery occurred in 62% of patients, generally before discharge. By 30 days LVEF increased >17% compared with baseline in the early recovery group with minimal increase in the no-early recovery group (48.9±8.8% versus 31.5±6.9%; P<0.001). One-year all-cause mortality was numerically (but not statistically) higher in the no-early recovery group (24% versus 12%; P=0.07). Absence of previous myocardial infarction (odds ratio, 0.44; 95% confidence interval, 0.19-1.03) and baseline mean gradient ≥40 mm Hg (odds ratio, 4.59; 95% confidence interval, 1.76-11.96) were identified as predictors of early LVEF recovery.

CONCLUSIONS

Nearly two thirds of patients with reduced LVEF will have a marked early improvement after transcatheter aortic valve replacement. Early LVEF recovery is associated with improved clinical outcomes and is most likely among patients with higher baseline aortic valve gradients and no previous myocardial infarction.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01240902.

Does the presence of coronary artery disease affect the outcome of aortic valve replacement?

The purpose of this study is to compare the late outcome of aortic valve replacement with or without preoperative coronary artery disease, and with or without coronary artery bypass. Between 2014 and 2015, 291 patients underwent aortic valve replacement. Average follow-up term was 2.5 ± 2.2 years. The retrospective comparative study was performed between the patients with (n = 115) or without (n = 176) preoperative coronary artery disease (Study 1) and with (n = 93) or without (n = 198) coronary artery bypass grafting (Study 2). Study 1: male patients were more, and diabetes was more in the patients with coronary artery disease. Long-term survival rate was significantly low in the patients with coronary artery disease (p = 0.0002 by log rank test). Freedom from repeat coronary revascularization rate was lower in the patients with coronary artery disease (p = 0.02 by log rank test). Study 2: operation time (419 ± 130 vs 290 ± 101; p = 0.0001) was longer in the patients with coronary artery bypass grafting. Improvement of ejection fraction at follow-up was more in the patients with coronary artery bypass(114 ± 43 vs 104 ± 26%; p = 0.03). Long-term survival rate and freedom from major adverse cardiac event rater were not different with or without coronary artery bypass grafting (p = 0.26 and p = 0.59, respectively, by log rank test). Although prevalence of coronary artery disease inversely affected the long-term outcome of the aortic valve replacement, simultaneous coronary artery bypass did not. Aggressive simultaneous coronary revascularization would be important to improve the long-term outcome of aortic valve replacement.

Transcatheter Aortic Valve Replacement 2016: A Modern-Day "Through the Looking-Glass" Adventure

Transcatheter aortic valve replacement (TAVR) has become a safe and effective therapy for patients with severe aortic stenosis (AS). In recent trials, the hemodynamic performance and clinical outcomes of the latest generation of TAVR devices demonstrated at least parity with surgical outcomes in patients of similar risk. Many initial obstacles with TAVR have largely been overcome, including frequent access site complications and concerns about strokes and paravalvular leaks. Using a multidisciplinary heart team approach, patient selection, procedural planning, and device implantation have been refined and optimized such that clinical outcomes are generally predictable and reproducible. Future research will focus on the durability of TAVR devices, further enhancements in clinical outcomes, and adjunctive therapies. On the basis of initial results from ongoing clinical trials, the indication for TAVR will likely expand to lower-risk patients. This review provides an overview of recent progress in this field, and highlights future opportunities and directions.