New frontiers in aortic therapy: focus on current trials and devices in transcatheter aortic valve replacement

Neuroprotective measures throughout the TAVI pathway

Aortic stenosis (AS) is the most common clinical valvular heart disorder that warrants active treatment. Symptomatic and severe AS is associated with increased morbidity and mortality if left untouched. Transcatheter aortic valve implantation (TAVI) is an innovative therapeutic modality approved initially for patients with prohibitive surgical risk and subsequently became a mainstream practice and the preferred treatment modality for many patients with severe AS at high and moderate surgical risk. Consistently global TAVI volumes have increased and indications continue to widen toward younger and lower-risk patients. However, periprocedural stroke is one of the most feared complications of TAVI, and when clinically evident, it is often associated with significant increase in mortality, physical disability, social isolation and financial costs. Furthermore, even when clinically overt stroke is not evident following TAVI, highly sensitive imaging modalities have demonstrated new post-procedural ischemic lesions in most patients. Although little is known about the long-term clinical significance of these lesions, there are strong signals showing they might be related with reduced subsequent neurocognitive function. This review provides a comprehensive contemporary insight of the definitions, incidence and temporal trends of stroke in TAVI patients, as well as the mechanisms, etiologies and risk factors for such neurological events. Furthermore, an integrated approach of neuroprotective measures targeted to reduce the incidence of stroke during each phase of the periprocedural TAVI pathway is suggested with a special focus on the role of embolic protective devices.

Transcatheter Aortic Valve Replacements: Current Trends and Future Directions

Since the 1960s when the first aortic surgical aortic valve replacement (SAVR) was performed, continuous growth in the field of valvular technology has occurred. Although SAVR remains a lifesaving procedure, minimally invasive transcatheter aortic valve replacement has revolutionized and expanded aortic valve replacement to patients who were not previously SAVR candidates, increasing their quality of life and survival. Since its introduction in the United States in 2011, the technology and practice have rapidly expanded. Hybrid techniques have been developed that combine surgical access to the vasculature with valvular deployment over transcatheter systems. This literature review aims to describe the differences between the current available valve technologies, review approaches to surgical technique, discuss anesthetic considerations, and look forward to future directions, trends, and challenges.

Utilization and 1-Year Mortality for Transcatheter Aortic Valve Replacement and Surgical Aortic Valve Replacement in New York Patients With Aortic Stenosis: 2011 to 2012

OBJECTIVES

The purpose of this study was to investigate changes in the use of transcatheter aortic valve replacement (TAVR) relative to surgical aortic valve replacement (SAVR) and to examine relative 1-year TAVR and SAVR outcomes in 2011 to 2012 in a population-based setting.

BACKGROUND

TAVR has become a popular option for patients with severe aortic stenosis, particularly for higher-risk patients.

METHODS

New York's Cardiac Surgery Reporting System was used to identify TAVR and SAVR volumes and to propensity match TAVR and SAVR patients using numerous patient risk factors contained in the registry to compare 1-year mortality rates. Mortality rates were also compared for different levels of patient risk.

RESULTS

The total number of aortic valve replacement patients increased from 2,291 in 2011 to 2,899 in 2012, an increase of 27%. The volume of SAVR patients increased by 7.1% from 1,994 to 2,135 and the volume of TAVR patients increased 157% from 297 to 764. The percentage of SAVR patients that were at higher risk (≥3% New York State [NYS] score, equivalent to a Society of Thoracic Surgeons score of about 8%) decreased from 27% to 23%, and the percentage of TAVR patients that were at higher risk decreased from 83% to 76%. There was no significant difference in 1-year mortality between TAVR and SAVR patients (15.6% vs. 13.1%; hazard ratio [HR]: 1.30 [95% confidence interval (CI): 0.89 to 1.92]). There were no differences among patients with NYS score <3% (12.5% vs. 10.2%; HR: 1.42 [95% CI: 0.68 to 2.97]) or among patients with NYS score ≥3% (17.1% vs. 14.5%; HR: 1.27 [95% CI: 0.81 to 1.98]).

CONCLUSIONS

TAVR has assumed a much larger share of all aortic valve replacements for severe aortic stenosis, and the average level of pre-procedural risk has decreased substantially. There are no differences between 1-year mortality rates for TAVR and SAVR patients.

[Interventional therapy of aortic valve stenosis in Germany]

BACKGROUND

Transcatheter aortic valve implantation (TAVI) has gained importance in recent years for the treatment of symptomatic aortic stenosis in Germany.

OBJECTIVE

This article discusses the indications, the procedure itself and safety issues in TAVI.

MATERIAL AND METHODS

Randomized controlled trials, registry studies, guidelines and expert recommendations are discussed.

RESULTS

Inoperable patients as well as patients ≥ 75 years with a high perioperative risk and patients ≥ 85 years should primarily be treated by TAVI. The decision must be made following discussions in a heart team. If no contraindications are detected the TAVI procedure should be performed via the transfemoral approach with the patient under conscious sedation. In recent years there has been a significant reduction in complication rates.

CONCLUSION

In Germany TAVI is the standard of care for surgical high-risk and inoperable patients with aortic valve stenosis.

Periprocedural considerations of transcatheter aortic valve implantation for anesthesiologists

Transcatheter aortic valve replacement (TAVR) is rapidly gaining popularity as a viable option in the management of patients with symptomatic aortic stenosis (AS) and high risk for open surgical intervention. TAVR soon expanding its indications from "high-risk" group of patients to those with "intermediate-risk". As an anesthesiologist; understanding the procedure and the challenges inherent to it is of utmost importance, in order to implement optimal care for this generally frail population undergoing a rather novel procedure. Cardiac anesthesiologists generally play a pivotal role in the perioperative care of the patients, and therefore they should be fully familiar with the circumstances occurring surrounding the procedure. Along with increasing experience and technical developments for TAVR, the procedure time becomes shorter. Due to this improvement in the procedure time, more and more anesthesiologists feel comfortable in using monitored anesthesia care with moderate sedation for patients undergoing TAVR. A number of complications could arise during the procedure needing rapid diagnoses and occasionally conversion to general anesthesia. This review focuses on the periprocedural anesthetic considerations for TAVR.

The future of transcatheter aortic valve implantation

Since the introduction of transcatheter aortic valve implantation (TAVI) into clinical practice, the treatment of aortic stenosis has changed dramatically. In the past, medical therapy with or without balloon aortic valvuloplasty was the only option for inoperable patients. More recently, TAVI has become the treatment of choice for these patients and the preferred alternative for high-risk operable patients. Surgical aortic valve replacement (SAVR) currently remains the gold standard for patients at low or intermediate operative risk. As randomized trials have demonstrated comparable results between TAVI and SAVR in the high-risk population, there is now a clear trend towards performing TAVI even in intermediate-risk patients while awaiting the results of randomized trials in that population. Nevertheless, there are still questions regarding TAVI involving paravalvular leak (PVL), stroke, pacemaker requirements, and durability that remain to be more definitively answered before TAVI can routinely be performed in a broader, lower risk population. Improvements in patient selection, imaging, and second and third generation devices have decreased the incidence of PVLs and vascular complications that followed the earliest TAVI procedures, but the rates of perioperative stroke and permanent pacemaker implantation must still be addressed. Furthermore, the long-term durability of TAVI devices and a role for post-procedure antithrombotic management remain unanswered. Until these questions are more clearly answered, it is the Heart Team's task to determine the optimal treatment for each patient based on risk scores, frailty metrics, comorbidities, patient preference, and potential for improvement in quality of life.

A comparison of conventional surgery, transcatheter aortic valve replacement, and sutureless valves in "real-world" patients with aortic stenosis and intermediate- to high-risk profile

OBJECTIVE

We sought to investigate the clinical outcomes of patients with isolated severe aortic stenosis and an intermediate- to high-risk profile treated by means of conventional surgery (surgical aortic valve replacement), sutureless valve implantation, or transcatheter aortic valve replacement in a multicenter evaluation.

METHODS

Among 991 consecutive patients with isolated severe aortic stenosis and an intermediate- to high-risk profile (Society of Thoracic Surgeons score >4 and logistic European System for Cardiac Operative Risk Evaluation I >10), a propensity score analysis was performed on the basis of the therapeutic strategy: surgical aortic valve replacement (n = 204), sutureless valve implantation (n = 204), and transcatheter aortic valve replacement (n = 204). Primary end points were 30-day mortality and overall survival at 24-month follow-up; the secondary end point was survival free from a composite end point of major adverse cardiac events (defined as cardiac-related mortality, myocardial infarction, cerebrovascular accidents, and major hemorrhagic events) and periprosthetic regurgitation greater than 2.

RESULTS

Thirty-day mortality was significantly higher in the transcatheter aortic valve replacement group (surgical aortic valve replacement = 3.4% vs sutureless = 5.8% vs transcatheter aortic valve replacement = 9.8%; P = .005). The incidence of postprocedural was 3.9% in asurgical aortic valve replacement vs 9.8% in sutureless vs 14.7% in transcatheter aortic valve replacement (P< .001) and peripheral vascular complications occurred in 0% of surgicalaortic valve replacement vs 0% of sutureless vs 9.8% transcatheter aortic valve replacement (P< .001). At 24-month follow-up, overall survival (surgical aortic valve replacement = 91.3% ± 2.4% vs sutureless = 94.9% ± 2.1% vs transcatheter aortic valve replacement = 79.5% ± 4.3%; P < .001) and survival free from the composite end point of major adverse cardiovascular events and periprosthetic regurgitation were significantly better in patients undergoing surgical aortic valve replacement and sutureless valve implantation than in patients undergoing transcatheter aortic valve replacement (surgical aortic valve replacement = 92.6% ± 2.3% vs sutureless = 96% ± 1.8% vs transcatheter aortic valve replacement = 77.1% ± 4.2%; P < .001). Multivariate Cox regression analysis identified transcatheter aortic valve replacement as an independent risk factor for overall mortality hazard ratio (hazard ratio, 2.5; confidence interval, 1.1-4.2; P = .018).

CONCLUSIONS

The use of transcatheter aortic valve replacement in patients with an intermediate- to high-risk profile was associated with a significantly higher incidence of perioperative complications and decreased survival at short- and mid-term when compared with conventional surgery and sutureless valve implantation.

Moderate Aortic Stenosis and Coronary Artery Bypass Grafting: Clinical Update for the Perioperative Echocardiographer

Incidental aortic stenosis in the setting of coronary artery bypass surgery may be a perioperative challenge. The accurate assessment of the degree of aortic stenosis remains an important determinant. Although severe aortic stenosis is an indication for valve replacement, current guidelines advise a balanced approach to the management of moderate aortic stenosis in this setting. Multiple factors should be considered in a team discussion to balance risks versus benefits for the various management options in the given patient. The rapid progress in aortic valve technologies also offer alternatives for definitive management of moderate aortic stenosis in this setting that will likely become even safer in the near future.