Sandbox:tavr

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Seyedmahdi Pahlavani, M.D. [2]

Transcatheter Aortic Valve Replacement (TAVR) Procedure Guide Microchapters
Overview
Definition
Risk Assessment
Diagnosis
Treatment General Approach Choice of Intervention Type of Valve and Discharge Anticoagulation Therapy
Do's
Don'ts

Overview

During the past 50 years, surgical aortic valve replacement (SAVR) was the standard of care for patients with severe AS. Global aging has raised concerns about safety and possibility of surgical procedure in old patients with associated co-morbidities. Transcatheter aortic valve replacement (TAVR) created a new era of safety for this population and enabled physicians to replace the stenotic valve with more certainty.
Preoperation evaluation, selecting the appropriate imaging modality, issues in TAVR procedure and patient follow up are the areas of more focused importance.
We will describe these factors based on the recent expert consensus for TAVR procedure.

Definition

The most important step is to define the severity of AS and appropriate patient that need TAVR. Severe sypmtomatic (Stage D) AS is considered as TAVR candidate.

Severe symptomatic AS (stage D)
STAGE	DEFINITION	SYMPTOMS	VALVE ANATOMY	VALVE HEMODYNAMICS	HEMODYNAMIC CONSEQUENCES
D1	Symptomatic severe high-gradient AS	Exertional dyspnea or decreased exercise tolerance Exertional angina Exertional syncope or presyncope	Severe calcification or congenital stenosis with severely reduced opening	Vmax ≥ 4 m/s or mean ΔP ≥ 40 mmHg AVA ≤ 1.0 cm² but may be larger with mixed AS and AR	LV diastolic dysfunction Left ventricular hypertrophy May present with pulmonary hypertension
D2	Symptomatic severe low-flow/low gradient AS with reduced LVEF	Heart failure Angina Syncope or presyncope	Severe calcification or congenital stenosis with severely reduced leaflet motion	AVA ≤ 1.0 cm² with resting aortic Vmax < 4 m/s or mean ΔP ≥ 40 mmHg Dobutamine stress echo shows AVA ≤ 1.0 cm² with Vmax ≥ 4 m/s at any flow rate	LV diastolic dysfunction Left ventricular hypertrophy LVEF <50%
D3	Symptomatic severe low gradient with normal LVEF	Heart failure Angina Syncope or presyncope	Severe calcification with severely reduced leaflet motion	AVA ≤ 1.0 cm² with Vmax < 4 m/s or mean ΔP ≤ 40 mmHg AVA ≤ 0.6 cm² Stroke volume index < 35 mL/m²	Increased LV relative wall thickness Small LV chamber with low stroke volume Restrictive diastolic filling LVEF ≥ 50%

TAVR Pathway outline

Abbreviations: CV: Cardiovascular, AVR: aortic valve replacement, AS: aortic stenosis, MR: Mitral regurgitation, AR: Aortic regurgitation, PAP: Pulmonary artery pressure, RV: right ventricle, CTA: CT angiography, PA: Pulmonary artery, TEE: Trans Esophageal Echocardiography, TTE: Trans Thoracic Echocardiography

Care Providing Team

Primary Care Provider                     Clinical Cardiologist                     Heart Valve Team: Cardiology Valve Expert CV Imaging Expert(s) Interventional Cardiologist CT Surgeon CV Anesthesiologist Valve Clinic Care Coordinators                     Hands off back to the Primary Care Provider and Clinical Cardiologist

Clinical Evaluation

AS Symptoms or Signs                   Severe AS with Indication for AVR                   Potential TAVR Candidate                   Patient Selection & Evaluation Shared Decision Making ❑ Goals of Care Clinical Information • Major CV comorbidites • Major non-CV comorbidities • Risk score assessment ❑ Functional Assessment • Frailty • Physical and cognitive function ❑ Risk Categories • Low risk • Intermediate risk • High or extreme risk                   TAVR Procedure ❑ Preplanning • Valve choice and access options • Anesthesia and procedure location • Anticipated complication management ❑ Procedural Details • Vascular access and closure • Valve delivery and deployment • Postdoploymont evaluation • Management of complications                   Post TAVR Management ❑ Early Post TAVR • Postprocedure monitoring and pain management • Early mobilization and discharge planning • Monitor for conduction abnormalities ❑ Long term Management • Antithrombotic therapy and endocarditis prophylaxis • Management of concurrent cardiac disease • Post-TAVR complications

Cardio-vascular Imaging

Pre TAVR ❑ Echo • Aortic valve anatomy • Confirm AS severity • LV function • MR. AR. PAP. RV function ❑ TAVR protocol CTA • Vascular access • Annular sizing • Aortic root anatomy • Interventional planning                   Echo ❑ (TEE or TTE) • Annular sizing • Valve placement • Paravalvular leak • Procedural complications                   Post TAVR Imaging ❑ Echo and ECG post-procedure, at 30 days and then annually • Valve function • LV size and function • PA systolic pressure • Cardiac rhythm

Risk Assessment

Underlying risk for SAVR is basic component to consider patient for TAVR. This risk assessment is based on several components that include:

• The Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) score. To calculate this score please click here.

• Frailty
• Main organ system dysfunction
• Procedure-specific impediments

SAVR risk assessment
Risk Index	Low Risk (Must meet ALL criteria in This column)	Intermediate Risk (Any 1 criterion in this column)	High Risk (Any 1 criterion in this column)	Prohibitive Risk (Any 1 criterion in this column)
STS PROM	<4%	4% to 8%	>8%	Predicted risk with surgery of death or major morbidity (all-cause) >50% at 1 y
Frailty†	None	1 Index (mild)	≥ 2 Indices (moderate to severe)	Predicted risk with surgery of death or major morbidity (all-cause) >50% at 1 y
Major organ system compromise not to be improved postoperatively‡	None	1 Organ system	No more than 2 organ systems	≥ 3 Organ systems
Procedure specific impediment ¶	None	Possible procedure specific impediment	Possible procedure specific impediment	Severe procedure specific impediment

† Seven frailty indices include: Katz Activities of Daily Living (independence in feeding, bathing, dressing, transferring, toileting,and urinary continence) and independence in ambulation (no walking aid or assist required or 5-meter walk in <6 s).

‡ Examples of major organ system compromise:

1. Cardiac: severe LV systolic or diastolic dysfunction or RV dysfunction, fixed pulmonary hypertension
2. CKD stage 3 or worse
3. Pulmonary dysfunction with FEV1 <50% or DLCO <50% of predicted
4. CNS dysfunction (dementia, Alzheimer’s disease, Parkinson’s disease, CVA with persistent physical limitation)
5. GI dysfunction: Crohn’s disease, ulcerative colitis, nutritional impairment, or serum albumin <3.0
6. Cancer: active malignancy
7. Liver: any history of cirrhosis, variceal bleeding, or elevated INR in the absence of VKA therapy.

¶ Examples: tracheostomy present, heavily calcified ascending aorta, chest malformation, arterial coronary graft adherent to posterior chest wall, or radiation damage.

Integrated Benefit-risk of TAVR and Shared Decision-making

AS Severity

Less than stage D

Stage D

❑ Periodic monitoring of AS severity and symptoms ❑ Re-evaluate when AS severe or symptoms occur

Severe symptomatic AS but Benefit < Risk (futility)

AVR indicated

❑Life expectancy <1 year ❑Chance of survival with benefit at 2 years <25%

SAVR preferred over TAVR

TAVR preferred

❑Discussion with patient and family ❑Palliative care inputs ❑Palliative balloon aortic valvuloplasty in selected patients

❑Lower risk for surgical AVR ❑Mechanical valve preferred ❑Other surgical considerations

Consider: ❑Symptom relief or improved survival ❑Possible complications and expected recovery ❑Review of goals and expectations

❑SAVR recommended in lower-risk patients ❑Valve durability considerations in younger patients ❑Concurrent surgical procedure needed (e.g.aortic root replacement)

❑Discussion with patient and family ❑Proceed with TAVR imaging evaluation and procedure

Heart Valve Team

Patients with severe AS should be evaluated by a multidisciplinary Heart Valve Team when intervention is considered.
Team members include:

• Cardiology Valve Expert
• Cardiovascular Imaging Expert(s)
• Interventional Cardiologist
• Cardio-Thoracic Surgeon
• Cardiovascular Anesthesiologist
• Valve Clinic Care Coordinators

Their specific tasks are:

1. Review the patient's medical condition and the severity of the valve abnormality
2. Determine which interventions are indicated, technically feasible, and reasonable
3. Discuss benefits and risks of these interventions with the patient and family, keeping in mind their values and preferences.

Initial Assessment

Initial Asseeement
Key Steps	Essential Elements	Additional Details
AS symptoms and severity	Symptoms AS severity	Intensity, acuity Echo and other imaging
Baseline clinical data	Cardiac history Physical exam and labs Chest irradiation Dental evaluation Allergies Social support	Prior cardiac interventions Routine blood tests, PFTs Access issues, other cardiac effects Treat dental issues before TAVR Contrast, latex, medications Recovery, transportation, post discharge planning
Major CV comorbidity	Coronary artery disease	Coronary angiography
	LV systolic dysfunction	LV ejection fraction
	Concurrent valve disease	Severe MR or MS
	Pulmonary hypertension	Assess pulmonary pressures
	Aortic disease	Porcelain aorta (CT scan)
	Peripheral vascular disease	Prohibitive re-entry after previous open heart surgery (CT scan) Hostile chest
Major non CV comorbidity	Malignancy	Remote or active, life expectancy
	Gastrointestinal and liver disease	IBD, cirrhosis, varices, GIB, ability to take antiplatelets/anticoagulation
	Kidney disease	eGFR <30cc/min or dialysis
	Pulmonary disease	Oxygen requirement, FEV1 <50% predicted or DLCO<50% predicted
	Neurological disorders	Movement disorders, dementia

Functional Assessment

Functional Asseeement
Key Steps	Essential Elements	Additional Details
Frailty and Disability	Frailty Assessment	Gait Speed (<0.5m/sec or < 0.83 m/sec with disability/cognitive impairment) Frailty (Not Frail or Frail by Assessments)
	Nutritional Risk/Status	Nutritional Risk Status (BMI<21, albumin <3.5mg/dl, >10-pound weight loss in past year, or ≤11 on MNA)
Physical Function	Physical function and endurance Independent living	6-minute walk <50 m or unable to walk Dependent in>=1 activities
Cognitive Function	Cognitive Impairment Depression and Prior Disabling Stroke	MMSE <24 or dementia Depression history or positive screen
Futility	Life expectancy Lag-time to benefit	<1 year life expectancy Survival with benefit of <25% at 2 years

Frailty

• Evaluation for frailty, physical function and independence in the activities of daily living (ADL) such as, feeding, bathing, toileting and transferring).
• Evaluation should be start with screening for independence, cognition and slow walking speed (gait speed, 3 timed trials over a 5 meter distance).
• Those with gait speed over 0.83 m/s, preserved cognition and independence are likely not frail.

Physical functioning

To assess the physical functioning, the 6 minute walk test should be done. It is possible to perform this test in outpatient setting.

Cognitive Functioning

The Mini Mental Status Examination (MMSE) is utilized to assess the cognitive status and scores less than 24 are considered as abnormal. Also, evaluation for depression must be done by using a validated tool such as, the Center for Epidemiologic Studies Depression Scale.

Futility

Those patients with <1 year life expectancy and who has a chance of survival with benefit of <25% at 2 years.
Survival with benefit means, survival with improvement by at least 1 New York Heart Association class in heart failure or by at least 1 Canadian Cardiovascular Society class angina symptoms, improvement in quality of life or improvement in life expectancy.

Imaging for TAVR

General Principles and Technical Considerations

• Transthoracic Echocardiography (TTE) is the best initial imaging modality for evaluating AS severity. Although, multimodality imaging is needed for preprocedural planning and intraoperative decision making given the complex 3D anatomy of the aortic valve, sinuses, and annulus.
• Multi-Detector CT (MDCT) is a core element of the standard imaging pathway for the preprocedural planning of TAVR.
• In patients being evaluated for TAVR, MDCT systems with at least 64 detectors and a spatial resolution of 0.5 to 0.6 mm are recommended.
• Evaluation of kidney function to avoid contrast induced nephropathy must be taken in to consideration.

Abbreviations: CV: Cardiovascular, AVR: Aortic valve replacement, AS: Aortic Stenosis, MR: Mitral Regurgitation, AR: Aortic Regurgitation, PAP: Pulmonary Artery Pressure, RV: Right Ventricle, CTA: CT angiography, PA: Pulmonary Artery, TEE: Trans Esophageal Echocardiography, TTE: Trans Thoracic Echocardiography AVA: Aortic Valve Area; CMR: Cardiovascular Magnetic Resonance Imaging; CT: Computed Tomography; ECG: Electrocardiogram; EF: Ejection Fraction; DSE: Dobutamine Stress Echocardiography; ESRD: End-Stage Renal Disease; GFR: Glomerular Filtration Rate; LFLG: Low-Flow Low-Gradient; LV: Left Ventricular; LVEF: Left Ventricular Ejection Fraction; MAC: Mitral Annular Calcification; MDCT: Multi Detector Computed Tomography; MRA: Magnetic Resonance Angiogram; MRI: Magnetic Resonance Imaging; MS: Mitral Stenosis; PET: Positron Emission Tomography; TAVR: Trans-catheter Aortic Valve Replacement

TAVR Imaging Checklist
Region of Interest	Recommended Approach and Key Measures	Additional Comments
Preprocedure
Aortic valve morphology	TTE: Trileaflet, bicuspid or unicuspid Valve calcification Leaflet motion Annular size and shape	TEE if can be safely performed, particularly useful for subaortic membranes Cardiac MRI if echocardiography nondiagnostic ECG-gated thoracic CTA if MRI contraindicated
Aortic valve function	TTE: Maximum aortic velocity Mean aortic valve gradient Aortic valve area Stroke volume index Presence and severity of AR	Additional parameters Dimensionless index AVA by planimetry (echo, CT, MRI) Dobutamine stress echocardiography for LFLG AS-Reduced EF Aortic valve calcium score if LFLG AS diagnosis in question
LV Geometry and other cardiac findings	TTE: LVEF, regional wall motion Hypertrophy, diastolic dysfunction Pulmonary pressure estimate Mitral valve (MR, MS, MAC) Aortic sinus anatomy and size	Myocardial ischemia and scar: CMR, PET, DSE, thallium CMR imaging for myocardial fibrosis and scar, identification of cardiomyopathies
Annular sizing	TAVR CTA- gated contrast enhanced CT thorax with multiphasic acquisition Typically reconstructed in systole 30-40% of the R-R window	Major/minor annulus dimension Major/minor average Annular area Circumference/perimeter
Aortic root measurements	Gated contrast-enhanced CT thorax with multiphasic acquisition. Typically reconstructed in diastole 60%–80%.	Coronary ostia heights Midsinus of Valsalva (sinus to commissure, sinus to sinus) Sinotubular junction Ascending aorta (40 cm above valve plane, widest dimension, at level of PA) Aortic root and ascending aorta calcification
Coronary disease and thoracic anatomy	Coronary angiography Nongated thoracic CTA	Coronary artery disease severity Bypass grafts: number/location RV to chest wall distance Aorta to chest wall relationship
Noncardiac imaging	Carotid ultrasound Cerebrovascular MRI	May be considered depending on clinical history

Vascular Access
Kidney Function Status	Recommended Approach	Key Parameters
Normal renal function (GFR >60) or ESRD not expected to recover	TAVR CTA	Aorta, great vessel, and abdominal aorta Dissection; atheroma; stenosis; calcification Iliac/subclavian/femoral luminal dimensions, calcification, and tortuosity
Borderline renal function	Contrast MRA Direct femoral angiography (low contrast)	Institutional dependent protocols Luminal dimensions and tortuosity of peripheral vasculature
Acute kidney injury or ESRD with expected recovery	Noncontrast CT of chest, abdomen, and pelvis Noncontrast MRA Can consider TEE if balancing risk/benefits	Degree of calcification and tortuosity of peripheral vasculature

TAVR Imaging Checklist
Imaging goals	Recommended Approach	Additional Details
Periprocedure
Interventional planning	TAVR CTA	Predict optimal fluoroscopy angles for valve deployment
Confirmation of annular sizing	Preprocedure MDCT	Consider contrast aortic root injection if needed 3C TEE to confirm annular size
Valve placement	Fluoroscopy under general anesthesia	TEE (if using general anesthesia)
Paravalvular leak	Direct aortic root angiography	TEE (if using general anesthesia)
Procedural complications	TTE TEE (if using general anesthesia) Intracardiac echocardiography (alternative)
Long-term Postprocedure
Evaluate valve function	TTE	Key elements of echocardiography: Maximum aortic velocity Mean aortic valve gradient Aortic valve area Paravalvular and valvular AR
LV geometry and other cardiac findings	TTE: LVEF, regional wall motion Hypertrophy, diastolic fucntion Pulmonary pressure estimate Mitral valve (MR, MS, MAC)

Specific CT measurements for TAVR

TAVR CT Measurement Summary
Valve Size and Type
Region of Interest	Specific Measurements	Measurement Technique	Additional Comments
Aortic valve morphology and function	Aortic valve	If cine images obtained, qualitative evaluation of valve opening Planimetry of aortic valve area in rare cases Calcium score with Agatston technique or a volumetric technique to quantify calcification of aortic valve	Most useful in cases of LFLG AS where diagnosis is otherwise unclear. May be helpful in defining number of valve cusps.
LV geometry and other cardiac findings	LV outflow tract	Measured with a double oblique plane at narrowest portion of the LV outflow tract Perimeter Area Qualitative assessment of calcification	Quantification of calcification not standardized. Large eccentric calcium may predispose for paravalvular regurgitation and annular rupture during valve deployment.
Annular sizing	Aortic annulus	Defined as double oblique plane at insertion point of all 3 coronary cusps Major/minor diameter Perimeter Area	Periprocedural TEE and/or balloon sizing can confirm dimensions during case.
Aortic root measurements	Sinus of Valsalva	Height from annulus to superior aspect of each coronary cusp Diameter of each coronary cusp to the opposite commissure Circumference around largest dimension Area of the largest dimension
Coronary and thoracic anatomy	Coronary arteries	Height from annulus to inferior margin of left main coronary artery and the inferior margin of the right coronary artery	Short coronary artery height increases risk of procedure. Evaluation of coronary artery and bypass graft stenosis on select studies. Estimate risk of coronary occlusion during valve deployment.
	Aortic root angulation	Angle of root to left ventricle Three-cusp angulation to predict best fluoroscopy angle	Reduce procedure time and contrast load by reducing number of periprocedural root injections
Vascular Access Planning
Vascular access	Aorta	Major/minor diameters of the following: Aorta at sinotubular junction Ascending aorta in widest dimension Ascending aorta prior to brachiocephalic artery Midaortic arch Descending aorta at isthmus Descending aorta at level of pulmonary artery Descending aorta at level of diaphragm Abdominal aorta at level of renal arteries Abdominal aorta at the iliac bifurcation	Measurements must be perpendicular to aorta in 2 orthogonal planes. Identify aortopathies. Evaluate burden of atherosclerosis. Identify dissection or aneurysms.
	Primary peripheral vasculature	Major/minor dimensions, tortuosity, calcification of the following: Carotid arteries Subclavian arteries Bracheocephalic artery Vertebral arteries Bilateral subclavian arteries Great vessels Iliac arteries Femoral arteries	No well-defined cutoff or definition of tortuosity or calcification has been established.
	Ancillary vasculature	Stenosis of the following: Celiac artery Superior mesenteric artery Both renal arteries
	Relationship of femoral bifurcation and femoral head	Distance from inferior margin of femoral head to femoral biforcation

TAVR Imaging Evaluation

TAVR CT

ECHO

Non-gated Angiogram of Chest, Abdomen and Pelvic Arteries for Vascular Access Selection

ECG-gated CT of Annulus and Aortic root for Valve Sizing Selection

Left Ventricle and other findings

Confirm Severe Aortic Stenosis

Transfemoral Approach

Annular Sizing

Aortic Root Sizing

Additional Procedural Planning

Subclavian Approach

Major/Minor Dimension

Coronary Ostia Height

Fluoroscopy Angulation

LVEF and LV Dimension

High Gradient AS

Apical Approach

Area

Aortic Sinus to Commissure Dimension

Bypass Grafts

Estimated Pulmonary Pressure

Low Gradient AS

Other Approaches

Circumferences

Sinotubular Junction

RV to Chest Wall Position

Other Valvular Abnormalities

Reduced EF

Carotid

Ascending Aorta Dimension

Preserved EF

Direct Aortic

Aortic Calcification

Transvenous

Preprocedural Evaluation

Aortic Valve Morphology

• Transthoracic Echocardiography (TTE) is performed for initial visualization of aortic valve to identify the number of leaflets; size, location, and extent of calcification; leaflet motion; and a preliminary view of annular size and shape.
• If additional imaging is needed, valve anatomy and function can be evaluated by cardiac magnetic resonance imaging (CMR) or ECG-gated MDCT.

Aortic Valve Function

Doppler echocardiography is superior to other imaging modalities to evaluate Aortic valve function. AS severity should be evaluated according to the ESE/ASE Recommendations for Evaluation of Valvular Stenosis and staged according to the AHA/ACC Guideline for the Management of Patients with Valvular Heart Disease.

LV Geometry and Other Cardiac Findings

TTE also is recommended for evaluation of LV hypertrophy, chamber size, LV diastolic function, regional wall motion, and ejection fraction as well as newer measures of LV function such as global longitudinal strain. In addition, TTE is useful for assessment of aortic dilation, presence of subvalvular outflow tract obstruction, estimation of pulmonary pressures, and identification of other significant valve abnormalities.

Annular Sizing

The 3D dataset provided by MDCT are more accurate than TTE findings regarding annular size. Measurement of LV outflow tract diameter on TTE has been well-validated for calculation of aortic valve area and continues to be the standard for determination of AS severity. CMR can also provide comprehensive assessment of the aortic valve, annulus, and aortic root with good correlation with MDCT. CMR can be a valuable tool in patients who cannot undergo MDCT.

Aortic Root Measurements

MDCT allows for the careful measurement of the size of the sinuses of Valsalva, the coronary ostia distance from the annulus, the size of the aorta at the sinotubular junction and 40mm above the annulus, and the extent and position of aortic calcifications.

Presurgical Planning

MDCT also may be of use in identification of coronary artery and coronary bypass graft location and stenosis, evaluation of the RV to chest wall position, and identification of the aorta and LV apex to chest wall position in direct aortic approaches.

Noncardiac Imaging

Because of high prevalence of dementia and atherosclerosis in this elderly patient population, a preprocedural work-up including carotid ultrasound and cerebrovascular MRI might be considered prior to considering or such patients for TAVR.

Vascular Access

Because of the relatively large diameter of the delivery sheaths, appropriate vascular access imaging is critical for TAVR. It is important to evaluate the entire thoracoabdominal aorta, major thoracic arterial vasculature, carotids, and iliofemoral vasculature. MDCT is able to provide valuable dataset regarding vascular anatomy.

Periprocedural Evaluation

Interventional Planning

MDCT can assist with predicting the optimal delivery angle on fluoroscopy prior to valve deployment.

Confirmation of annular sizing

Preprocedural MDCT is the best modality to evaluate annular size. At the time of the procedure, Fluoroscopy is the main imaging modality. If questions remain about the correct annular sizing, balloon inflation with contrast root injection can be performed. Also, 3D TEE is able to evaluate the annular size, at the time of the procedure.

Valve Placement

Optimal deployment angles are obtained using fluoroscopy and root injections. Deployment is done under fluoroscopy at many institutions, although TEE is an alternative approach.

Paravalvular Leak

TEE and TTE are required to assess the valve in different aspects. Also, TEE can be used to assess the immediate gradient changes after valve seating. Aortic root angiography also may be used to assess for regurgitation after valve implantation. As the volume of cases performed without general anesthesia increases, there may be an expanding role for periprocedural TTE.

Procedural Complications

Immediate complications such as annular rupture resulting in pericardial effusion and tamponade can be detected by TEE, TTE, angiography, and direct hemodynamic measurements.

References