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

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

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.