Journal of Cardiovascular and Cardiology

Innovations in Cardiovascular Care: The Safety and Outcomes of Transcatheter Aortic Valve Implantation

Silpa Choday*, Aubin Sandio, Austin Saugstad, Tamer Zahdeh and Ali Moradi

Innovations in Cardiovascular Care: The Safety and Outcomes of Transcatheter Aortic Valve Implantation

Silpa Choday^1*, Aubin Sandio², Austin Saugstad¹, Tamer Zahdeh³ and Ali Moradi¹

¹Creighton University School of Health Science, Department of Internal Medicine, AZ, USA
²Wayne State University, Department of Internal Medicine, MI, USA
³Montefiore St. Luke’s Cornwall, Department of Internal Medicine, NY, USA

*Corresponding author
Silpa Choday, Creighton University School of Health Science, Department of Internal Medicine, AZ, USA.

ABSTRACT
Background: Transcatheter aortic valve implantation (TAVI) represents a innovative advancement in cardiovascular surgery treatment for patients suffering from severe aortic stenosis. It was initially developed as an alternative for high-risk surgical candidates, TAVI has evolved to encompass a broader spectrum of patients, including those at intermediate and low surgical risk. 

Discussion: The evolution of TAVI has been marked by significant enhancements in procedural safety and efficacy. Technological innovations in valve design, delivery systems, and imaging techniques have substantially minimized procedural complications, such as stroke, vascular injury, and paravalvular leak. Furthermore, improvements in procedural techniques and experience have contributed to better patient outcomes. Long-term studies have highlighted the durability and effectiveness of TAVI in symptom relief, functional improvement, and overall survival rates. These outcomes have shown that TAVI as not just a viable alternative but often the preferred choice for many patients previously deemed unfit for conventional surgery.

Conclusion: In conclusion, TAVI stands at the forefront of cardiovascular innovation, reforming treatment standards and expanding therapeutic options for patients across a broad range. TAVI holds great potential to continue improving cardiovascular care and outcomes. As it becomes increasingly refined and accessible, TAVI will remain a keystone in the future of cardiovascular surgery, offering hope to patients who previously faced limited treatment options.

List of Abbreviations

TAVI	:	Transcatheter Aortic Valve Implantation
SAVR	:	Surgical Aortic Valve Replacement
AS	:	Aortic Stenosis
TEE	:	Transesophageal Echocardiography
SVD	:	Structural Heart Deterioration
AV	:	Aortic Valve
AVR	:	Aortic Valve Replacement

Keywords: Aortic Stenosis, Transcatheter Aortic Valve Replacement, Transcatheter Aortic Valve Implantation, Safety, Efficacy

Background
Aortic Stenosis is the most common cause of valvular heart disease and can be fatal if left untreated. According to the American College of Cardiology, this is a class I recommendation, one-third of the patients over the age of 75 are not being referred for surgery due to concern about surgical risk associated with the patient’s age, and other co-morbidities [1]. TAVI arose as a complementary option to surgical aortic valve replacement (SAVR) [2]. The standard treatment outcomes were established in a [Society of Thoracic Surgeons Predicted Risk of Mortality (STS) score >_8-15%] and d US Core Valve high-risk trials that TAVR is comparable to SAVR [3-5]. Transcatheter aortic valve implantation (TAVI) is a less invasive alternative and is the treatment of choice for high-operative risk patients compared to SAVR [6]. Developments in technology, refinements in procedures, and increased experience have resulted in improved treatment outcomes, resulting in an increased interest in using TAVI in patients [2]. In this review, we will summarize the most recent evidence on safety, the efficacy of the treatment outcomes, and emerging concepts in the field of TAVR.

Main Text/Discussion
Aortic stenosis (AS) has a predictable prevalence of 12% to 13%, and most of the most severe AS at age ≥75 is in the Western world, making it one of the most common structural heart diseases in the elderly [7]. Traditionally, severe AS was treated by SAVR or medical management [8]. TAVR has transformed the management of patients with severe aortic stenosis. Originally it was restricted to inoperable or high-risk patients, the indication of TAVR has expanded to low-risk and intermediate patients, and a series of clinical trials were conducted comparing TAVR with SAVR. TAVR is approved for all patients irrespective of age and all risk profiles [9]. It has shown good outcomes in short-term, 1-year, and 2-years with low-risk profiles and at the age of 70s [9].

Frailty in Older Adults
Frailty is one of the risk factors for death and can cause disability after TAVR and SAVR. FRATILYT AVR (aortic valve replacement) is designed to investigate the frailty in the older population who is undergoing SAVR and TAVR [10]. It predicts mortality and disability after an aortic valve (AV) procedure. It measures cognitive impairment, Lower extremity weakness, anemia, and hypoalbuminemia. Among the other frailty scales EFT outperformed, was quick and easy to predict the value, and has high reliability. In addition to frailty markers, other factors associated with poorer outcomes are atrial fibrillation, and pulmonary and renal disease when the patient is dialysis dependent [11]. Patients who are obese are likely to survive but have functional limitations after TAVR. It is beneficial to have cardiac rehabilitation in obese patients who are frail to improve their disability and functional decline [12].

Comparison of TAVR Vs SAVR
The long-term outcomes regarding the clinical and durability of transcatheter heart valves are better and more reassuring for TAVR. Based on one study patients who underwent TAVR in the USA had a 1-year mortality of 23%, stroke of 4%, but a combination of stroke and death of 26% [11]. After 5 years of follow-up in intermediate-risk patients with aortic stenosis, and chronic kidney disease, acute kidney injury is more common with SAVR than TAVR, but the other outcomes as death, stroke, progression to dialysis and readmission are similar in both groups [13]. At lower surgical risk patients after 6 years of follow-up, the all-cause mortality has only a slight difference, but TAVR (42.5%) is better than SAVR (37.7%), but the structural heart deterioration (SVD) is less for TAVR compared to SAVR, Nonstructural valve deterioration was similar in both groups [14]. Another study showed that there is no significant difference in TAVR and SAVR after 8 years of follow-up, the all-cause mortality, myocardial infarction and stroke, and composite outcomes, but the risk of structural valve deterioration is significantly lower with TAVR compared to SAVR [15]. In one study, that compared TAVI (n=458) and Surgery (n=455), it showed that TAVI is superior to surgery among patients aged>70 years [1]. TAVR is now recommended for longer life expectancy patients with TAVR [16].

TAVR in Women
Men and women have a similar prevalence of valvular disease [17]. Women undergo SAVR for AS less frequently than men and have worse outcomes with SAVR than men SAVR in women has been correlated with worse in‐hospital mortality and higher cost compared with men [18]. Numerous studies had reported mortality benefits for women with TAVR. A study by Siontis et al.22, for 2-year mortality - TAVR showed a 13% relative risk reduction compared to SAVR. This was observed to be more beneficial for females undergoing a transfemoral approach [19]. In another Panoulas et al1 study of gender‐specific survival combining 4 randomized controlled trials of TAVR vs SAVR with a total of 3758 patients (female: 1706, male 2052), women had significantly lower mortality than male 1 and 2 years with a reduction of 31% at 1 year and 26% at 2 years. The difference in treatment was statistically significant with p < 0.05 [17].

TAVR Over Age 90
TAVR can be performed in nonagenarians with high procedural success rates and acceptable in‐hospital, 30‐day, and 1‐year mortality rates. Most studies for patients above age 90 show a procedural success rate greater than 95% and an absolute stroke rate of less than 4%, with no effect modification by age. In a study by Sun et al, there is a similar rate of major bleeding in patients above and below 90 years, with a relative risk of 1.17 (95% CI 1.04 - 1.32) [20]. In contrast, if the nonfemoral access techniques were used the rate of vascular complication was increased for patients above 90 years. From the FRAILTY‐AVR study, nonfemoral access had higher 30‐day mortality in frail patients (odds ratio 3.91, 95% CI 1.48 - 10.31) [21]. Most studies show higher risk in nonfemoral access though the comparison of femoral and nonfemoral access routes is clearly not randomized but favors femoral access TAVR in older patients [22].

On average, patients above 90 years can tolerate the TAVR procedure quite well, with low in‐hospital mortality and low adverse effects. This subgroup of patients is under‐represented or at the very least highly selected in randomized trials, Age alone is inadequate to stratify patients, there must be deeper evaluations for frailty such as that offered by a comprehensive geriatric assessment. Finally, the process of mutual decision‐making is predominant to make sure that the course of action is patient‐centered and considers the anticipated risks and benefits with the nonagenarian's preferences and principles [22].

Delirium After TAVR
The development of TAVR has made an increased number of the elderly patient population with high comorbidities and frailty eligible for treatment compared to the pre-TAVR [23]. Post-procedure is a frequent complication with disturbance in consciousness, cognition, and attention. The rate of delirium varies from 2% to 4% [24]. The incidence of delirium yearly in the general population is anticipated at 1% to 2%, this number increases with age and can be up to 14% in elderly patients (age >85) [25]. In hospital admissions, delirium is noted in 14% to 24% [25]. The pooled incidences of delirium after cardiac surgery is noted to be 8% to 20% [26,27]. For TAVR the pooled incidence of delirium is 8% to 23% [28,29].

As TAVR is rapidly advancing there is improving awareness of delirium for preventive and therapeutic options [30]. Delirium has been related to impaired recovery, increased length of hospital stays, high cost for index hospitalization, increased risk of readmissions within 6 months, and mortality [31]. Treatment for delirium is established mainly on nonpharmacological strategies identifying and eliminating the trigger factors such as pain and infection, and optimization of environmental factors. TAVR-associated delirium can be avoided by addressing the predisposing and precipitating factors. In different hospital settings, interventions that reduced the incidence of delirium resulted in improved clinical outcomes and reduced costs [32].

Procedural Improvements
With the continuous development of TAVR, many advancements have been implemented in various procedures to improve outcomes and decrease the procedure burden. The primary goals of the procedure are to perform under local anesthesia and percutaneously [33]. Preventing general anesthesia during the procedure can have improved outcomes and reduced length of in-hospital stay [34]. This approach, however, excludes the standard use of transesophageal echocardiography (TEE). Monitoring of post-procedural aortic regurgitation with advanced TEE or non-imaging methods is needed [35]. The promotion of early mobilization can be achieved by using balloon-expandable sheaths and totally percutaneous TF-TAVR with advanced vascular closure devices [33].

Cost-Effectiveness
Apart from clinical outcomes, the price of the procedure is an important factor when choosing a treatment modality, notably in low healthcare-budget countries [33]. SAVR is associated with high predicted risk, and high costs when stratified by surgical risk category [36]. The benefits of TAVR come at a cost-effectively adequate cost in the higher-risk groups, but this may not apply to low-risk patients [37]. Ultimately, the anticipated variations in the cost of TAVR prostheses can be an important influencer of cost-efficacy when comparing TAVR and SAVR [38].

Conclusions
TAVR is a growing procedure with constant advancements in methods, selection of patients, and utilization of resources and devices. The outcomes have mostly been reliable and progressed since the launch of this procedure. However, there is room to decrease complications and enhance outcomes, which drives innovation in this area. In a very short time, there is a lot of tremendous evidence accumulated for TAVR as the patient population that benefits from this procedure continues to increase with time. As there is an upward trend in the preference for TAVR, there is also a trend toward improving the technology and techniques.

Declarations
Ethics approval and consent to participate: Not applicable 

Consent for publication: Not applicable.

Availability of data and material: Data has been collected from PubMed, Crossref and Google Scholar

Competing interests: The authors declare that they have no competing interests.

Funding: Not applicable.

Authors' contributions: SC as the first author analyzed and interpreted the data, wrote most of the sections, and was a major contributor to writing the manuscript. AS as the second author analyzed the sections and was a contributor to the few parts of the manuscript. AS as the third author collected relevant articles and contributed to a few sections of the article. TZ as the fourth author who has written the intro, conclusions and arranged references. AM as the senior author reviewed the article and made necessary changes to the manuscript. All authors read and approved the final manuscript.

Acknowledgements: None

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