Aortic stenosis surgery indications

Aortic stenosis surgery
Home
Overview
Epidemiology and Demographics
Indications
Treatment
Preoperative Evaluation
Procedure
Recovery
Outcomes and Prognosis
Complications
Videos
Aortic stenosis surgery indications On the Web
Most recent articles
Most cited articles
Review articles
CME Programs
Powerpoint slides
Images
American Roentgen Ray Society Images of Aortic stenosis surgery indications All Images X-rays Echo & Ultrasound CT Images MRI
Ongoing Trials at Clinical Trials.gov
US National Guidelines Clearinghouse
NICE Guidance
FDA on Aortic stenosis surgery indications
CDC on Aortic stenosis surgery indications
Aortic stenosis surgery indications in the news
Blogs on Aortic stenosis surgery indications
Directions to Hospitals Performing Aortic stenosis Surgery
Risk calculators and risk factors for Aortic stenosis surgery indications

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Sara Zand, M.D.[2] Mohammed A. Sbeih, M.D. [3]; Usama Talib, BSc, MD [4] Synonyms and keywords: As; Aortic stenosis; AVR; Aortic valve replacement; LVEF; Left ventricular ejection fraction

Overview

In symptomatic patients with severe high-gradient AS (Stage D1), evidence demonstrates the beneficial effects of AVR on survival, symptoms, and LV systolic function. In asymptomatic patients with severe AS and normal LV systolic function, the risk of sudden death (<1% per year) is low. However, in patients with a low LVEF and severe AS, survival is better with AVR than medical therapy.

Indications

• In symptomatic patients with severe high-gradient AS (Stage D1), AVR has beneficial effects on survival, symptoms, and LV systolic function.
• The most common initial symptom of AS is exertional dyspnea or decreased exercise tolerance.
• More severe classical symptoms of AS, including HF, syncope, or angina, can be avoided by appropriate treatment at the onset of even mild symptoms.
• Outcomes after surgical or transcatheter AVR are excellent.
• Improvement in exercise tolerance has been shown by exercise test after AVR.
• In asymptomatic patients with severe AS and normal LV systolic function, the risk of sudden death is low (<1% per year). However, in patients with a low LVEF and severe AS, survival is better in those who undergo AVR than in those treated medically.
• Disease progression occurs in nearly all patients with severe asymptomatic AS. Initiation of symptoms within 2 to 5 years is likely when aortic velocity is ≥4.0 m/s or mean pressure gradient is ≥40 mm Hg.

• Mean pressure gradient is a strong predictor of outcome after AVR, with better outcomes seen in patients with higher gradients.
• Outcomes are poor with severe low-gradient AS but are still better with AVR than with medical therapy in those with a low LVEF, especially in the presence of contractile reserve.
• Severe AS on dobutamine stress testing is defined when a maximum velocity >4.0 m/s with a valve area ≤1.0 cm2 at any point during the test protocol, with a maximum dobutamine dose of 20 mcg/kg per minute.
• Out come in patients without contractil reserve is poor with either surgical or medical therapy.
• In patients undergone AVR, LVEF typically increases by 10 LVEF units and may return to normal if afterload mismatch was the cause of LV systolic dysfunction.
• Low-flow, low-gradient severe AS with preserved LVEF should be considered in patients with a severely calcified aortic valve, an aortic velocity <4.0 m/s (mean pressure gradient <40 mm Hg), and a valve area ≤1.0 cm2, stroke volume index <35 mL/m2, presence of small LV cavity with thick walls, diastolic dysfunction, and a normal LVEF (≥50%).
• If hypertension is present, blood pressure should is controlled before reevaluation of AS severity.
• Valve area is indexed to body size because an apparent small valve area may be only moderate AS in a small patient.
• An aortic valve area index ≤0.6 cm2/m2 suggests severe AS.
• Transaortic stroke volume is calculated by Doppler or 2D imaging.
• Exercise testing may be helpful in clarifying symptom status in patients with severe AS including a fall of ≥10 mm Hg in systolic blood pressure from baseline to peak exercise or a significant decrease in exercise tolerance as compared with age and sex normal standards.
• In patients with very severe AS and an aortic velocity ≥5.0 m/s or mean pressure gradient ≥60 mm Hg, the rate of symptom onset is approximately 50% at 2 years. *Early surgery in patients with aortic velocity ≥4.5 m/s showed significant survival benefit.
• An elevated serum BNP level is a marker of subclinical HF and LV decompensation in severe AS.
• In asymptomatic patients with AS with the aortic velocity reaches ≥2 m/s, hemodynamic progression leading to symptom .
• Hemodynamic progression occurs when aortic velocity increases about 0.3 m/s per year, an increase in the mean gradient of 7 to 8 mm Hg per year, and a decrease in valve area of 0.15 cm2 per year.
• Predictors of rapid disease progression include older age, more severe valve calcification, and a faster rate of hemodynamic progression in serial studies.
• Elective AVR may be considered In patients with an aortic velocity >4 m/s, and the presence of predictors of rapid disease progression.
• In adults with initially asymptomatic severe AS, the rate of sudden death is low (<1% per year). However, an aortic velocity ≥5 m/s or an LVEF <60% is associated with higher all-cause and cardiovascular mortality rates in the absence of AVR.
• A progressive decrease in LVEF is most likely in those with an LVEF <60% before AS becomes severe.
• Hemodynamic progression eventually leading to symptom onset occurs in nearly all asymptomatic patients with AS.

. The rate of symptom onset is strongly dependent on the severity of AS.

• Patients with asymptomatic AS require periodic monitoring for the development of symptoms and progressive disease.

Recommendations for intervention in aortic stenosis

Symptomatic aortic stenosis:

(Class I, Level of Evidence B):

❑ Intervention is considered in symptomatic patients with severe, high-gradient aortic stenosis, mean gradient ≥ 40 mmHg, peak velocity ≥ 4.0 m/s, and valve area ≤ 1.0 cm2 (or ≤ 0.6 cm2/m2) ❑ntervention is considered in symptomatic patients with severe low-flow (SVi ≤35 mL/m2), low-gradient (<40 mmHg) aortic stenosis with reduced ejection fraction (<50%), and evidence of flow (contractile) reserve

(Class IIa, Level of Evidence C):

❑ Intervention is recommended in symptomatic severe AS with low-flow, low-gradient (<40 mmHg) aortic stenosis with normal ejection fraction ❑ Intervention is recommended in symptomatic patients with low-flow, low-gradient severe aortic stenosis and reduced ejection fraction without flow (contractile) reserve, severe aortic stenosis proven by CCT calcium score

(Class III, Level of Evidence C) :

❑ Intervention is not recommended in patients with severe comorbidities when the intervention is unlikely to improve quality of life or prolong survival >1 year

Asymptomatic severe aortic stenosis :

(Class I, Level of Evidence B):

❑ Intervention is recommended in asymptomatic patients with severe aortic stenosis and systolic LV dysfunction (LVEF < 50%) without another cause

(Class I, Level of Evidence C):

❑ Intervention is recommended in asymptomatic patients with severe aortic stenosis, symptomtomatic on exercise testing

(Class IIa, Level of Evidence B):

❑ Intervention should be considered in asymptomatic patients with severe aortic stenosis and systolic LV dysfunction (LVEF <55%) without another cause

(Class IIa, Level of Evidence C):

❑ Interventin is recommended in asymptomatic patients with severe aortic stenosis and a sustained fall inblood pressure (>20 mmHg) during exercise testing

(Class IIa, Level of Evidence B):

❑Intervention is considered in asymptomatic patients with LVEF >55% and a normal exercise test if the procedural risk is low and in the presence of one of the following: Very severe aortic stenosis (mean gradient ≥60 mmHg or Vmax > 5 m/s Severe valve calcification ( assessed by CCT) and Vmax progression ≥0.3 m/s/year Elevated BNP levels (>3× age- and sex-corrected normal range) confirmed by repeated measurements and without other causes

Type of intervention:

(Class I, Level of Evidence C):

❑Aortic valve interventions should be performed in an experienced center

(Class I, Level of Evidence B):

❑SAVR is recommended in younger patients who are low risk for surgery (<75 yearse and STS PROM/EuroSCORE II <4%), or in patients who are operable and unsuitable for transfemoral TAVI ❑SAVR or TAVI are recommended for patients based on clinical, anatomical, and procedural characteristics

(Class I, Level of Evidence A):

❑TAVI is recommended in older patients (≥75 years), or in those who are high risk (STS PROM/EuroSCORE IIf>8%) or unsuitable for surgery

(Class IIb, Level of Evidence C):

❑ Non-transfemoral TAVI may be considered in patients who are inoperable and unsuitable for transfemoral TAVI ❑Balloon aortic valvotomy may be considered as a bridge to SAVR or TAVI in hemodynamically unstable patients and (if feasible) in those with severe aortic stenosis who require urgent high risk non-cardiac surgery

Abbreviations: BNP: B-type natriuretic peptide; CABG: Coronary artery bypass grafting; LV: Left ventricle; LVEF:Left ventricular ejection fraction ; CCT:Cardiac computed tomography; SAVR: Surgical aortic valve replacement; STS-PROM: Society of Thoracic Surgeons - predicted risk of mortality; SVi: Stroke volume index; TAVI:Transcatheter aortic valve implantation ; Vmax:Peak transvalvular velocity

The above table adopted from 2021 ESC Guideline

Valvular AS Assessment of velocity, gradient

Low-gradient AS Vmax < 4 m/s ΔPm < 40 mmHg

High-gradient AS Vmax ≥ 4 m/s, ΔPm ≥ 40 mmHg

AVA ≤ 1.0 cm2

High flow status

Yes Determination of flow status

NO Moderate AS

Yes Assessment of normal flow condition

NO Severe AS

Normal flow SVi > 35 mL/m2

Low flow SVi ≤ 35 mL/m2

Severe AS unlikely

LVEF ≥ 50%

NO DSE flow reservec

Yes CCT to assess AV calcification

NO, CCT to assess AV calcification

Yes, AVA ≤ 1.0 cm2

Yes Severe AS

NO Pseudo-severe AS

Abbreviations: AS: Aortic stenosis; AV: Aortic valve; AVA: Aortic valve area; LVEF: Left ventricular ejection fraction ; CT: Computed tomography; △Pm: Mean pressure gradient; DSE: Dobutamine stress echocardiography; LV: Left ventricular; SVi: Stroke volume index; Vmax: Peak transvalvular velocity

The above table adopted from 2021 ESC Guideline

• High flow is reversible in conditions such as anemia, hyperthyroidism orarterio-venous fistula and may also be present in patients with hypertrophic obstructive cardiomyopathy.
• Normal flow by pulsed Doppler echocardiography is defined as:

  Cardiac index 4.1 L/min/m2 in men and women

  SVi 54 mL/m2 in men, 51 mL/m2 in women

• DSE flow reserve is defined as > 20% increase in stroke volume in response to low-dose dobutamine.
• Pseudo-severe aortic stenosis is defined when AVA >1.0 cm2 with increased flow.
• CT measurement of aortic valve calcification (Agatston units) for definition of AS severity:

  High likely: men >3000, women>1600

  Likely: men >2000, women >1200

  Unlikely: men <1600, women <800

Recommendations for choice of Mechanical Versus Bioprosthetic AVR

(Class I, Level of Evidence C):

❑ Decision should be made based on patients preference and values after discussion about the risks of anticoagulant therapy or the need for valve intervention ❑ Bioprothesis AVR is recommended when anticoagulant theray with VKA is contraindicated, not desired, or can not be managed

(Class IIa, Level of Evidence B):

❑Mechanical aortic prothesis is preferred over bioprosthetic valve for patients < 50 years of age and no contraindication of anticoagulant therapy ❑For patients 50-65 years of age without contraindication of anticoagulant therapy, choosing either mechanical or bioprothesis aortic valve should be individualized based on patient factors ❑ For patients > 65 years of age, bioprosthetic aortic valve is preferred over mechanical aortic valve

(Class IIb, Level of Evidence B):

❑For patients <50 years of age who desire bioprosthetic valve and appropriate anatomy, the Rose procedure including replacement of aortic valve by a pulmonic autograft may be considered

The above table adopted from 2020 AHA Guideline

Abbreviations: AVR: Aortic valve replacement; VKA: Vitamin K antagonist