Aortic Valve Replacement

Absolute and relative contraindications for transcatheter aortic valve replacement

Absolute contraindications

Absence of a “heart team” and no cardiac surgery on the site

Appropriateness of TAVI as an alternative to AVR, not confirmed by a “heart team”

Clinical

Estimated life expectancy less than 1 year

Improvement of quality of life by TAVI unlikely because of comorbidities

Severe primary associated disease of other valve with major contribution to the patient’s symptoms that can be treated only by surgery

Anatomic

Inadequate annulus size (<18 mm, >29 mm^a)

Thrombus in the left ventricle

Active endocarditis

Elevated risk of coronary ostium obstruction (asymmetric valve calcification, short distance between annulus and coronary ostium, small aortic sinuses)

Plaques with mobile thrombi in the ascending aorta or arch

For transfemoral/subclavian approach: inadequate vascular access (vessel size, calcification, tortuosity)

Relative contraindications

Bicuspid or noncalcified valves

Untreated coronary artery disease requiring revascularization

Hemodynamic instability

LVEF less than 20%

For the transapical approach: severe pulmonary disease, LV apex not accessible

Abbreviations: AVR aortic valve replacement, LV left ventricle, LVEF left ventricular ejection fraction, TAVI transcatheter aortic valve implementation

Data from: Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC)1; European Association for Cardio-Thoracic Surgery (EACTS), Vahanian A, Alfieri O, et al. Guidelines on the management of valvular heart disease (version 2012). Eur Heart J. 2012 Oct;33(19):2451–96

^aContraindication when using the current devices

The current recommendations for use of TAVR as laid out by the American College of Cardiology/American Heart Association guidelines and the European Society of Cardiology/European Association of Cardio-Thoracic Surgery are listed in Fig. 10.1 [7, 8]. However it is likely that guidelines for TAVR use will move progressively to lower risk patients.

../images/301959_1_En_10_Chapter/301959_1_En_10_Fig1_HTML.png — Fig. 10.1

Recommendations for choice of mechanical biological aortic valve prosthesis. Class I indicated recommended; class IIa indicates should be considered; and class IIb indicates may be considered. *Abbreviations: AHA* American Heart Association guidelines, *ESC* European Society of Cardiology guidelines. From Otto CM, Baumgartner H. Updated 2017 European and American guidelines for prosthesis type and implantation mode in severe aortic stenosis. Heart. 2018 May;104(9):710–713. Reprinted with permission from BMJ Publishing Group Ltd.

Risk Stratification

Patients being evaluated for TAVR must be evaluated by a “heart team” which includes cardiologists, cardiac surgeons, anesthesiologists, and other specialists as needed to develop a comprehensive understanding of each patient’s risk and guide them towards appropriate therapies. Patients must be evaluated with a goal to separate patients who are severely ill with aortic stenosis from those who are severely ill due to severe aortic stenosis.

Risk stratification is key in the TAVR evaluation because appropriateness of use is in part determined by level of risk. The current accepted method for risk stratification includes calculation of either the Society of Thoracic Surgeons (STS) projected risk of mortality (PROM) score [9] or the Logistic European Score for Cardiac Operative Risk Evaluation (LES Euroscore) [10]. Both these scoring systems have been used in several TAVR registries as well as randomized clinical trials to risk stratify patients for TAVR. Overall, the LES Euroscore overestimates mortality in high-risk patients undergoing SAVR and was not appropriately calibrated to estimate mortality after TAVR. The STS score is probably more realistic in estimating mortality and morbidity after SAVR. An STS mortality score cutoff of >4% is used to certify intermediate or surgical high risk, the current criteria for TAVR use.

Newer scoring systems including the EuroSCORE II [11], ACEF (Age, creatinine, ejection fraction) score, TVT TAVR In Hospital Mortality Score, and the Aortenklappenregister score [12] have been developed to better predict patient outcomes after TAVR. Although the STS and EuroSCORE II score are well established in predicting surgical risk , neither was specifically developed for TAVR patients. Newer models that incorporate frailty, prohibitive anatomy including porcelain aorta and severe aortic calcification, oxygen dependency, pulmonary hypertension, RV dysfunction, cirrhosis, dementia, physical deconditioning and malnutrition, and access options are greatly needed and are being developed to better stratify patients for whom TAVR is a better option than SAVR. Such a model should accurately predict both early and late mortality as well as improvement in quality of life metrics. Hopefully, with the combined analyses of the PARTNER trials, CoreValve trials, and the US Transcatheter valve Therapeutics (TVT) National Database, a TAVR specific risk algorithm could be developed and validated [13].

Patient Screening

Appropriate patient screening is the cornerstone for the success of any TAVR program. Optimal screening includes a comprehensive evaluation by the heart team followed by a thorough review of patient’s anatomical, functional, and imaging data to delineate the appropriate treatment strategy, procedural details, as well as post procedure care. Figure 10.2 is a representation of the workflow associated with optimal patient screening by the heart team.

../images/301959_1_En_10_Chapter/301959_1_En_10_Fig2_HTML.png — Fig. 10.2

Decision-making by the multidisciplinary heart team on patients referred for transcatheter aortic valve replacement (TAVR). The multidisciplinary team considers and weighs the various risk factors shown and makes a decision regarding whether TAVR would be beneficial or futile. *BAV indicates balloon aortic valvuloplasty.* From Agarwal S, Tuzcu EM, Kapadia SR. Choice and Selection of Treatment Modalities for Cardiac Patients: An Interventional Cardiology Perspective. J Am Heart Assoc. 2015 Oct;4(10):e002353. Published online 2015 Oct 20. https://dx.doi.org/10.1161%2FJAHA.115.002353. Copyright © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell. Open Access

Imaging

Imaging is key in the workup of a patient for TAVR and is typically done using several modalities including transthoracic echocardiography (TTE) , multi-slice detector computed tomography (MDCT) , angiography , transesophageal echocardiography (TEE) including 3D TEE as well as MRI (Table 10.1). A comprehensive preprocedural echocardiogram is performed to evaluate the aortic valve morphology, calcification, hemodynamics, concomitant mitral valve disease, left ventricular dimensions and function, right heart function, and pulmonary hypertension. One of the most important aspects of imaging includes evaluation of the ilio-femoral access for size, tortuosity, and calcification for transfemoral approach. This is typically accomplished using MDCT , although some centers use angiography for the same purpose. Assessment of aortic annulus size is crucial to determine the appropriate size of the prosthesis and is accomplished using 3D TEE and MDCT (Figs. 10.3 and 10.4).

Table 10.1

Preprocedural transthoracic assessment

Pre-procedural echocardiographic imaging
• Aortic valve and root − Aortic valve morphology Bicuspid versus tricuspid Degree and location of calcium − Annular dimensions Minimum and maximum diameters Perimeter Area − Aortic valve hemodynamics Aortic valve gradients and area Stroke volume Impedance − Left ventricular outflow tract Extent and distribution of calcium Presence of sigmoid septum − Aortic root dimensions and calcification Sinus of Valsalva diameter Sinotubular junction diameter and calcification Location of coronary ostia and risk of obstruction
• Mitral valve − Severity of mitral regurgitation − Presence of mitral stenosis − Severity of ectopic calcification Anterior leaflet calcification
• Left ventricular size and function − Wall motion assessment Exclude intracardiac thrombus − Left ventricular mass Hypertrophy and septal morphology − Assessments of function Ejection fraction Strain and torsion Diastolic function
• Right heart − Right ventricular size and function − Tricuspid valve morphology and function − Estimate of pulmonary artery pressures

Pre-procedural echocardiographic imaging

• Aortic valve and root

− Aortic valve morphology

Bicuspid versus tricuspid

Degree and location of calcium

− Annular dimensions

Minimum and maximum diameters

Perimeter

Area

− Aortic valve hemodynamics

Aortic valve gradients and area

Stroke volume

Impedance

− Left ventricular outflow tract

Extent and distribution of calcium

Presence of sigmoid septum

− Aortic root dimensions and calcification

Sinus of Valsalva diameter

Sinotubular junction diameter and calcification

Location of coronary ostia and risk of obstruction

• Mitral valve

− Severity of mitral regurgitation

− Presence of mitral stenosis

− Severity of ectopic calcification

Anterior leaflet calcification

• Left ventricular size and function

− Wall motion assessment

Exclude intracardiac thrombus

− Left ventricular mass

Hypertrophy and septal morphology

− Assessments of function

Ejection fraction

Strain and torsion

Diastolic function

• Right heart

− Right ventricular size and function

− Tricuspid valve morphology and function

− Estimate of pulmonary artery pressures

From: Hahn RT, et al. Recommendations for comprehensive intraprocedural echocardiographic imaging during TAVR. JACC Cardiovasc Imaging. 2015 Mar;8(3):261–87. Reprinted with permission from Elsevier

../images/301959_1_En_10_Chapter/301959_1_En_10_Fig3_HTML.jpg — Fig. 10.3

Annular measurements by three-dimensional (3D) imaging . Panels A and B are MSCT images with annular area measurement of 351 mm² and left main coronary height of 13.1 mm. Panels C and D are 3D TEE images with annular area of 354 mm² and left main coronary height of 13.3 mm. From Hahn RT. Guidance of transcatheter aortic valve replacement by echocardiography. Curr Cardiol Rep. 2014 Jan;16(1):442. Reprinted with permission from Springer

../images/301959_1_En_10_Chapter/301959_1_En_10_Fig4_HTML.jpg — Fig. 10.4

MDCT should be used to assess safety and ideal access approach for TAVR. Identification of patients with severe iliofemoral tortuosity and calcification (a), previous bypass grafts and their relationship to the sternum to plan transaortic procedures (b) and aortic disease such as dissection (c) and aneurysm (d) is critical to evaluate prior to TAVR. From Sintek M, Zajarias A. Patient evaluation and selection for transcatheter aortic valve replacement: the heart team approach. Prog Cardiovasc Dis. 2014 May–Jun;56(6):572–82. Reprinted with permission from Elsevier

Specific Comorbidities and Their Roles in Patient Selection

Comorbidities play an important role in evaluating patients for TAVR. Certain conditions pose a prohibitive surgical risk from a technical standpoint and may lead to TAVR being the preferred treatment option in patients with severe symptomatic AS. However, these conditions also increase the risk associated with TAVR implantation and must be carefully considered during patient screening. They include radiation heart disease, heavily calcified ascending aorta (porcelain aorta), multiple prior chest surgeries, prior sternal wound infection, and bypass graft anatomy including left internal mammary artery adherent anteriorly to the posterior wall of the sternum. Similarly severe LV dysfunction, small (<18 mm) or large (>27 mm) aortic annulus, left main coronary ostia within 10 mm of the annulus, intracardiac mass/thrombus/vegetation as well as severe pulmonary hypertension are relative contraindications for the implantation of TAVR. Other specific comorbidities including chronic kidney disease, concomitant mitral valve disease, underlying coronary artery disease, chronic lung disease, and systolic left ventricular dysfunction are associated with worse outcomes in patients undergoing TAVR and must be considered in detail during the preprocedural assessment (Table 10.2).

Table 10.2

Specific comorbidities influencing patient selection for TAVR

Comorbidity	Relevance to selection for TAVR
CKD	Presence of CKD predicts worse outcome after TAVR. Preprocedural creatinine >1.58 mg/dL is associated with six fold increased risk of mortality
Coronary artery disease	Presence indicates more extensive vascular disease. Need for staged or concomitant revascularization needs to be assessed. The ongoing ACTIVATION trial is evaluating the role of PCI in TAVR patients
Mitral valve disease	Up to one-third of patients evaluated for TAVR have severe MVD. Presence indicates more extensive CVD limiting TAVR effectiveness
Systolic dysfunction	TAVR is generally safe and efficacious. More adverse events but similar overall mortality. Marked improvements in LVEF have been reported after TAVR at 30 days
CLD	Present in 20–30% of TAVR patients. Improved survival and functional capacity compared with medical therapy. Frail patients may not benefit from TAVR in presence of CLD

From: Sarkar K, Sarkar M, Ussia GP. Current status of transcatheter aortic valve replacement. Med Clin North Am. 2015 Jul;99(4):805–33. Reprinted with permission from Elsevier. CKD chronic liver disease; CLD chronic lung disease.

Chronic Kidney Disease (CKD)

Patients with severe CKD and those on dialysis have been excluded from TAVR randomized trials and the long-term benefits of the procedure in these patients are unknown. Additionally, patients with CKD have a higher risk of prosthesis degeneration possibly due to abnormal calcium metabolism.

Preoperative renal function is an important predictor of mortality and morbidity in patients undergoing surgery for valvular heart disease [14]. Underlying CKD is a risk factor for acute kidney injury postoperatively. In patients with CKD, TAVR is associated with a lesser risk of acute kidney injury than SAVR and may even result in improved renal function post intervention [15–17]. Despite this, underlying CKD is still associated with worse outcomes and a higher chance of AKI post TAVR [18]. Patients who develop AKI post procedure have a higher mortality and increased cost and length of hospitalization. Preprocedural creatinine more than 1.58 mg/dL was associated with a sixfold increased risk of death in one study [19]. A meta-analysis of over 40,000 patients found worse in-hospital morbidity and mortality for CKD patients and an even worse prognosis for patients with end-stage renal disease compared to patients with normal renal function [20]. Special emphasis must be given to limit the amount of contrast and space contrast studies to prevent contrast-induced nephropathy in these patients.

Coronary Artery Disease

Significant coronary artery disease is common in up to 40–75% of patients with severe AS being evaluated for TAVR [21]. Patients with severe CAD usually have worse vascular disease and may have a higher likelihood of needing the transapical approach for valve deployment. Although a commonly encountered comorbidity, the overall impact of the presence of concomitant CAD on outcomes in patients undergoing TAVR is not well understood and needs further exploration. In a recent study, CAD increased 2 year TAVR mortality by twofold [22]. Additionally, the optimum the timing of revascularization and stent type need to be further investigated in trials. Revascularization before TAVR may be pursued due to a simpler access to the coronaries and lower risk of ischemia and hemodynamic instability during rapid pacing and valve deployment. The ischemic burden, complexity of procedure, and anticipated contrast load should be taken into account while planning revascularization prior to TAVR. Revascularization with percutaneous coronary intervention should be pursued for severely stenotic lesions, which subtend a large area of myocardium at risk with several centers reporting successful staged and concomitant PCI with 1 year survival of more than 80% [23–25]. Whether revascularization should be done before TAVR vs. as a combined procedure is an important question and the currently enrolling ACTIVATION trial will help in clarifying this conundrum [26, 27].

Mitral Valve Disease

Concomitant mitral regurgitation (MR) may be present in up to one-third of patients being evaluated for TAVR [28]. Patients with severe mitral valve disease who undergo TAVR usually have a higher incidence of atrial fibrillation, pulmonary arterial hypertension, and RV dysfunction. Although it is expected that severe MR will improve after TAVR, it is not clear which patients will improve the most and in some cases MR worsens instead of improves [29]. In general patients with organic mitral disease and lower transaortic gradients are most likely to have persistent MR post TAVR. A recent multivariate analysis suggests that mitral regurgitation is not associated with worsening survival after TAVR [30], although the presence of concomitant mitral valve disease is a marker of more advanced disease and may limit the effectiveness of TAVR. Patients with significant mitral regurgitation and severe aortic stenosis may be considered for percutaneous treatment of both lesions with the recent approval of the MitraClip device [31].

Systolic Dysfunction

Patients with LVEF <20% were excluded from the PARTNER trial and most patients had LVEF >45% [21]. A single-center retrospective study by Ewe et al. showed that patients undergoing TAVR implantation with EF < 50% had higher adverse events but similar procedural and total mortality compared to those with LVEF >50% [32]. Another study showed that in patients with EF <35% implanted with a Medtronic Corevalve device, the 30-day mortality was similar to those with LVEF >35% and that a greater proportion of TAVR low EF patients showed improvement in LVEF when compared to matched SAVR controls [33, 34]. Indeed, most patients with systolic dysfunction show an improvement in LVEF after TAVR. RV function often worsens after SAVR, but usually remains stable post TAVR [35, 36].

Low-gradient severe AS (LG-AS) is associated with a worse prognosis in patients undergoing SAVR [37], with mortality as high as 35% in patients with no contractile reserve [38]. In patients with LG-AS who survive SAVR, there is improvement in outcomes suggesting a role for TAVR in these patients. Mortality is higher in patients with LG-AS who undergo TAVR as compared to those with normal gradients and may approach 33% at 6 months [39]. This is due in part to underlying LV dysfunction and also to a higher prevalence of pulmonary arterial hypertension, severe mitral regurgitation, CAD, and PAD in these patients, all of which affect outcomes in patients undergoing TAVR [40]. Nonetheless survival is improved in LG-AS patients compared to “medical” therapy [41] and patients with LG-AS who survive TAVR have an improvement in functional capacity, six-minute walk distance as well as larger improvement in LVEF compared to matched SAVR patients [34, 39, 40]. Low-dose dobutamine stress echocardiography has been used successfully to assess for contractile reserve and SAVR outcome in patients with LG-AS [38]. This technique has also been used to separate patients with true from pseudo aortic stenosis undergoing TAVR. Patients with low-flow, low-gradient, low-EF AS have the worst prognosis while high-gradient patients have the best prognosis [42]. The former patients have low EF because of severe LV dysfunction while the latter have low EF based upon high afterload that is immediately corrected by TAVR.

Chronic Lung Disease (CLD)

About 20–30% patients in TAVR and SAVR registries have chronic lung disease [43–45]. Presence of severe chronic lung disease is associated with an increased 1 year mortality in patients who undergo SAVR as well as TAVR [45]. Patients with severe chronic lung disease who undergo TAVR have an improvement in their 1 year outcomes as compared to patients treated with medical management [46]. However, oxygen-dependent chronic lung disease is associated with worse outcomes, especially 1 year all-cause mortality [46]. Severe CLD when associated with a poor 6-minute walk test is associated with a fivefold increased risk of non-CV mortality [46]. All patients undergoing evaluation for TAVR should have lung function assessed and the presence of chronic lung disease , especially in frail patients, should be carefully evaluated as these patients may not benefit as much from TAVR [47].

Frailty vs. Futility

Frailty is described as a state of decreased physiological reserve predisposing to poor outcomes, but not necessitating poor outcomes. It is affected by physical disability and medical comorbidities and is an impairment in medical systems that leads to a decline in resiliency and homeostatic reserve. Commonly accepted key domains of frailty include weakness, slowness, exhaustion, low activity, weight loss, and poor nutrition. Frailty is defined by a composite of several other factors including gait speed, grip strength, 6-min walk test, serum albumin, Katz activities of daily living, weakness, cognitive dysfunction, and several others [48]. Although it is not completely captured in the current risk stratification models, frailty is noted in about 50% of the patients referred for TAVR and has been associated with worse outcomes in patients undergoing TAVR [49–51].

Gait speed is a simple test that has been shown to be predictive of frailty in TAVR and overall mortality [52–54]. Patients who ambulate slower than 0.5 m/s or who ambulate less than 128.5 m during a 6-min walk test have similar procedural mortality but have increased long-term mortality [55]. Frailty in the PARTNER clinical trials was assessed by walk speed, grip strength, serum albumin, and the Katz activity of daily living dependency questionnaire; to be considered inoperable on the basis of frailty, three of those four domains must have been abnormal [50]. Further assessment of frailty using the Multi-Dimensional Geriatric assessment (MGA) showed that adding MGA-based information to risk models improved prediction of 30 day and 1 year mortality and MACCE [49]. Green et al. developed a frailty score for TAVR patients and noted that impaired gait speed, grip strength, reduced serum albumin, and diminished Katz activities of daily living were associated with increased 1 year mortality as well as longer post TAVR hospital stay [55]. In the recent multicenter FRAILTY-AVR study which compared outcomes in elderly patients undergoing TAVR and SAVR, the Essential Frailty Toolset that employed lower extremity weakness, cognitive impairment, anemia, and hypoalbuminemia was superior to other frailty indexes and was prognostic of 30-day mortality and worsening disability at 1 year [56].

A comprehensive frailty assessment also helps differentiate patients with “futility” rather than “high-risk” or “inoperability” as these patients have both poor survival (less than 1 year) and poor quality of life despite successful TAVR. Common clinical characteristics associated with these patients include a high STS score (STS > 15), extreme frailty usually with dependent social status, severe pulmonary and liver disease, severe dementia, chronic kidney disease (dialysis dependent), and hemodynamic instability (especially requiring pressors). Further research is needed to help better identify patients unlikely to benefit from TAVR during the screening phase based on frailty metrics and risk stratification models (Table 10.3).

Table 10.3

Frailty assessment for patients being evaluated for transcatheter aortic valve replacement

Frailty test	Description
Gait speed	>7 s to walk 5 m abnormal
Grip strength	Dynamometer; <30 kg in nonobese man and <18 kg in nonobese woman is abnormal
6-min walk test	<128.5 m during 6-min walk test
Comprehensive Assessment of Frailty (CAF)	Grip strength, gait speed, instrumental activities of daily living questionnaire, standing balance test, serum albumin, brain natriuretic peptide, and creatinine. Proprietary scoring algorithm used to measure frailty
Multidimensional Geriatric Assessment (MGA)	Mini-mental state examination, timed get up and go test, basic and instrumental activities of daily living questionnaires. Frailty index score generated and score ≥3 indicated frailty

From: Sarkar K, Sarkar M, Ussia GP. Current status of transcatheter aortic valve replacement. Med Clin North Am. 2015;99(4):805–33. Reprinted with permission from Elsevier

Access Screening

The first TAVR by Dr. Cribier was performed using the antegrade trans-septal approach. However, most TAVRs currently use the transfemoral (TF) approach , the default route for valve implantation in patients with suitable ilio-femoral anatomy. Access screening is an important part of the procedure preparation and includes assessment of ileofemoral size, tortuosity and calcification using MDCT or angiography so as to establish feasibility of TF approach. In patients with unsuitable ilio-femoral anatomy, alternative access sites include transapical (TA), transaortic (TAo), trans-axillary, transcarotid, and trans-caval access. The most common alternative access route for the Edwards valve is the TA route, wherein the valve prosthesis is delivered in an antegrade fashion through the LV apex, while a trans-axillary access route is used for CoreValve implantation for patients with unsuitable ilio-femoral anatomy. Newer generation devices have a lower profile with sheath size as small as 14 Fr for the 23 and 26 mm TF Edward Sapien 3 valve. As a result, most patients being evaluated for TAVR will likely be candidates for a TF approach. In the recent PARTNER II trial 77% of patients were treated from the femoral approach while in the SURTAVI trial 93% were treated from the femoral approach [57, 58] and it is likely that this approach will become even more dominant as TAVR valves become increasingly smaller in profile. The potential advantages of the TA approach include avoiding tortuous and diseased ilio-femoral vasculature, and having a prosthesis co-axial with the aortic annulus. The disadvantages of this approach include the need for a thoracotomy, myocardial injury and left ventricular pseudo-aneurysm from apical perforation of the ventricle and bleeding complications from the surgical site. In patients who are not candidates for either TF or TA or trans-axillary approach because of poor vascular access, poor pulmonary function or chest pathology, the valve prosthesis may be delivered using a retrograde approach by direct cannulation of the ascending aorta or the carotid artery or the subclavian artery. Additionally, in a smaller subset of patients trans-caval aortic access can be performed, which involves accessing the femoral vein to facilitate entry into the abdominal aorta through puncture of the inferior vena cava followed by standard valve implantation using TF technique. The technique for TF and TAVR is described in Table 10.4.

Table 10.4

Transfemoral (TF) transcatheter aortic valve replacement (TAVR): procedural steps

• Access. A 6-F to 7-F introducer is used to access femoral artery that is upsized to an 18-F to 22-F introducer sheath

• The native stenotic aortic valve is crossed with a diagnostic Amplatz Left (AL-1) catheter and straight tip wire

• A Super Stiff Amplatz (SSA-1 wire) with a hand-shaped pigtail loop at the end is placed in the LV apex in stable position using the right anterior oblique projection

• A preimplantation balloon aortic valvuloplasty is routinely performed under rapid right-ventricular pacing with an undersized balloon (1–2 mm smaller than the measured aortic annulus diameter) for preparing the native annulus in all cases except pure aortic regurgitation or degenerated aortic bioprosthesis

• A pigtail catheter is positioned in the noncoronary cusp as a marker for the annular plane and for contrast injections during the valve deployment. The image intensifier is positioned at the implant angle defined as the optimal left anterior oblique (LAO) projection for aligning the nadir of all three coronary cusps in a straight line. The valve is positioned across the aortic annulus and deployed under rapid pacing (Edwards)

• For self-expandable core valve (CRS) deployment, the delivery catheter system (DCS) is positioned such that the horizontal markers of the device are positioned (4–6 mm) below the level of the pigtail catheter (CRS)

• The DCS is maintained as perpendicular to the annular plane as possible and the release is initiated under fluoroscopic and angiographic guidance with repeated small contrast injections (10 mL to 10 mL/s at 900 psi) through the pigtail catheter

From: Sarkar K, Sarkar M, Ussia GP. Current status of transcatheter aortic valve replacement. Med Clin North Am. 2015 Jul;99(4):805–33. Reprinted with permission from Elsevier

Valve Sizing and Positioning

There are several guidelines and consensus statements regarding the essential role of multidisciplinary imaging in patient selection and procedural guidance for patients undergoing TAVR implantation [59, 60]. Imaging guidance with multi detector CT (MDCT) and TEE are both key in valve sizing and positioning . Valve sizing is established using protocols specific for the valve type employed and implantation is optimized by concurrent TEE and fluoroscopy after determination of the appropriate co-planar implantation view and appropriate height and implantation depth of the prosthesis. A three-dimensional understanding of the complex anatomy of the aorta, LVOT and the aorto-mitral continuity is essential to appropriate valve deployment and functioning. Appropriate sizing and placement of the device will lead to excellent hemodynamics, minimal paravalvular leak, low pacemaker implantation rate and prevention of coronary obstruction and injury to the annulus.

Current Transcatheter Valve Replacement Platforms

The Edwards-Sapien Valve

The Edwards Sapien Valve (Edwards Lifesciences, Irvine, CA) was an improved version of the first balloon-expandable valve (BEV) implanted by Cribier et al. in 2002 (Fig. 10.5). The original Edwards Sapien valve consisted of a tubular slotted stainless steel frame and leaflets made of bovine pericardium, which were pretreated to decrease valve calcification. Additionally the fabric skirt, made of polyethylene terephthalate, was extended further to improve sealing and potentially reduce paravalvular regurgitation. This valve was available in two sizes (23 and 26 mm) requiring 22 F and 24 F delivery catheters for TF approach implantation, respectively.

../images/301959_1_En_10_Chapter/301959_1_En_10_Fig5_HTML.jpg — Fig. 10.5

Evolution of the Edwards balloon-expandable transcatheter valves (a) and Medtronic self-expandable valves (b) (sheath compatibility for a 23 mm valve.) From Hamm CW, Arsalan M, Mack MJ. The future of transcatheter aortic valve implantation. Eur Heart J. 2016 Mar 7;37(10):803–10. Reprinted with permission from Oxford University Press

The Sapien XT valve (Edwards Lifesciences, Irvine, CA) is a third generation of balloon-expandable Edwards valves, consisting of a trileaflet pericardial bovine valve, mounted in a cobalt chromium stent frame. The Sapien XT valve is available in 20-, 23-, 26-, and 29-mm sizes, and is implanted through the transfemoral approach using the NovaFlex delivery system implanted through 16 F (20-, 23-mm valves), 18 F (26-mm valve), or 20 F (29-mm valve) expandable sheaths (e-sheath, Edwards Lifesciences, Irvine, CA).

The Sapien 3 THV (Edwards Lifesciences, Irvine, CA) is the latest iteration of the balloon-expandable valves, and also consists of a trileaflet pericardial bovine valve that is mounted in a cobalt chromium stent. It too incorporates an additional outer skirt to further reduce the risk of paravalvular leak. The expanded length (20 mm) is slightly longer than the Sapien (16.1 mm) and Sapien XT (17.2 mm) THVs, which helps facilitate optimal positioning within the native aortic valve and annulus. Additionally, the delivery system (Commander) has an even lower profile and has been further improved to facilitate valve alignment and proper positioning Table 10.5).

Table 10.5

Proposed sizing algorithm using annular area (mm²) for the second- and third-generation balloon-expandable valves

	Valve size
	20 mm	23 mm	26 mm	29 mm
Nominal area, mm²	314	415	531	661
Annular range for second-generation balloon-expandable valve, mm²	257–310	298–410	420–530	530–660
Annular range for third-generation balloon-expandable valve, mm²	273–345	338–430	430–546	540–683

The nominal areas for each balloon-expandable valve size are listed (in mm²). The ranges of annular areas that can be covered are based on an acceptable oversizing range of 5–20% for the second-generation balloon-expandable valve, and a −5–20% oversizing with the third-generation balloon-expandable valve. (Note: a negative oversizing equates to undersizing of the valve, in which the native annulus can be up to 5% larger than the nominal area of the transcatheter valve)

From: Hahn RT, et al. Recommendations for comprehensive intraprocedural echocardiographic imaging during TAVR. JACC Cardiovasc Imaging. 2015 Mar;8(3):261–87. Reprinted with permission from Elsevier

The PARTNER I trial [61] was the first prospective randomized trial of the balloon-expandable Edwards-Sapien valve and included two distinct cohorts of patients: those considered to be inoperable or cohort B (i.e., comorbidities leading to a predicted risk of 50% or more of either death within 30 days after surgery or a serious irreversible condition); and those considered to be at high surgical risk or cohort A (i.e., predicted risk of operative mortality ≥15% as determined by site surgeon and cardiologist and/or a minimum STS score of 10) (Fig. 10.6, Tables 10.6 and 10.7). In the inoperable cohort, all-cause mortality (30.7% vs. 50.7%; P < 0.001), cardiovascular mortality (19.6% vs. 41.9%; P < 0.001), repeat hospitalization (22.3% vs. 44.1%; P < 0.001), and the composite endpoint of death or repeat hospitalization (42.5% vs. 71.6%; P < 0.001) were much lower in patients who were randomized to TAVR [61] (Figs. 10.7 and 10.8). TAVR resulted in a significant improvement in health-related quality of life as determined by the Kansas City Cardiomyopathy Questionnaire (KCCQ) [63] (Fig. 10.9). During follow-up, there was no evidence of degeneration of the valvular prosthesis or restenosis at 2 years [64]. At 5-year follow-up, the advantage of TAVR over medical therapy persisted [62]. Heart failure symptoms were less severe in patients treated with TAVR, but the TAVR patients also had a higher incidence of major vascular complications (16.2% vs. 1.1%; P < 0.001), major bleeding (22.3% vs. 11.2%; P < 0.001), and major strokes (5.0% vs. 1.1%; P = 0.06). Based on the results of this trial, TAVR became the new standard of care in patients with severe AS who are considered inoperable.

../images/301959_1_En_10_Chapter/301959_1_En_10_Fig6_HTML.png — Fig. 10.6

PARTNER trial design . From Holmes DR Jr., et al. 2012 ACCF/AATS/SCAI/STS expert consensus document on transcatheter aortic valve replacement. J Am Coll Cardiol. 2012 Mar 27;59(13):1200–54. Reprinted with permission from Elsevier

Table 10.6

Major outcomes at 30 days and 1 year in Cohort B of the PARTNER trial

Characteristic	30 days			1 year
Characteristic	TAVR (N = 179)	Standard Rx (N = 179)	p value	TAVR (N = 179)	Standard Rx (N = 179)	p value
All-cause death (%)	5.0	2.8	0.41	30.7	49.7	<0.001
All-cause death or rehospitalization (%)	11.2	12.3	0.74	43.6	70.4	<0.001
Event-free MACCE (%)	90.5	94.4	NR	65.4	47.1	0.003
All stroke (%)	7.3	1.7	0.02	11.2	4.5	0.03
Major stroke (%)	5.6	1.1	0.04	8.4	3.9	0.12
All-cause death or major stroke (%)^a	8.4	3.9	0.12	33.0	50.3	0.001
Major vascular complications (%)	16.8	1.1	<0.0001	17.3	2.2	<0.0001
Major bleeding (%)	20.6	3.9	<0.0001	28.4	14.4	<0.001
Pacemaker insertion (%)	3.4	5.0	0.60	4.5	7.8	0.27
Echocardiographic endpoints
AV area (EOA) (cm²)	1.5 ± 0.4	0.8 ± 0.2	<0.0001	1.6 ± 0.5	0.7 ± 0.32	<0.0001
Mean AV gradient (mmHg)	11.1 ± 6.6	33.0 ± 12.5	<0.0001	12.5 ± 10.3	44.4 ± 15.7	<0.0001

Cohort B includes only nonsurgical candidates in whom “inoperability” was formally defined as greater than 50% predicted probability of mortality or serious irreversible complication by 30 days by 1 cardiologist and 2 cardiothoracic surgeons

AV indicates aortic valve, EOA effective orifice area, MACCE major adverse cardiac and cerebrovascular events, NR not reported, Rx therapy, TAVR transcatheter aortic valve replacement

Data are based on Edwards Lifesciences’ briefing document for the U.S. FDA Circulatory Devices Advisory Panel meeting on TAVR on July 21, 2011 (http://www.accessdata.fda.gov/cdrh_docs/pdf10/P100041b.pdf), and may show some discrepancies compared with the published manuscripts

From Holmes DR Jr., et al. 2012 ACCF/AATS/SCAI/STS expert consensus document on transcatheter aortic valve replacement. J Am Coll Cardiol. 2012 Mar 27;59(13):1200–54. Reprinted with permission from Elsevier

^aAll-cause death or major stroke was not a predefined endpoint

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Tags: Valvular Heart Disease

Apr 23, 2020 | Posted by admin in CARDIOLOGY | Comments Off

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