Assessment of aortic valve disease - a clinician oriented review

Table 1 Echocardiographic criteria for the definition of severe aortic stenosis: Advantages and disadvantages[18]

Criteria	Severe AS	Advantages	Disadvantages
Aortic surface area	≤ 1.0 cm2	Measures effective AVA. However, this may also constitute a disadvantage because it does not measure anatomical AVA	Very sensitive to measurement errors
		Less flow-dependent compared with other measurements
Indexed AVA to body surface area	≤ 0.6 cm2/m2	Useful for extreme heights/weights	Very sensitive to measurement errors
Mean transaortic pressure gradient	≥ 40 mmHg		Flow-dependent
			Requires correct alignment of Doppler signal with the flow direction
Peak transaortic flow velocity	≥ 4.0 m/s	Measures instantaneous velocity	Flow-dependent
		Best predictor of adverse events	Requires correct alignment of Doppler signal with the flow direction
Ratio between peak transaortic flow velocity and peak LVOT velocity	≤ 1/4	Good reproducibility (compared with AVA calculation)	Limited data on prognostic utility

AS: Aortic stenosis; AVA: Aortic valve area; LVOT: Left ventricular outflow tract.

Table 2 Indication for aortic valve replacement according to European Society of Cardiology/European Association for Cardio-Thoracic Surgery and American Heart Association/American College of Cardiology guidelines[33,34]

Criteria	Level of recommendation		Differences between guidelines
	ESC/EACTS	AHA/ACC
Severe AS with any symptoms clearly due to AS, based on history or unmasked by stress test	I	I	"High-gradient" in AHA/ACC guidelines
Asymptomatic severe AS with LVEF < 50%	I	I
Severe AS and another indication for surgery (CABG, thoracic aorta, another valve)	I	I
Asymptomatic severe AS where the systolic blood pressure does not increase by > 20 mmHg or drops compared with baseline during the treadmill test	IIa	IIa	AHA/ACC guidelines acknowledge the presence of fatigability during stress test as an indication for AVR
Moderate AS and another indication for surgery (CABG, thoracic aorta, another valve)	IIa	IIa
Low-flow/low-gradient/low-LVEF severe AS with proof of contractile reserve presence	IIa	IIa
Symptomatic low-flow/low-gradient/preserved LVEF severe AS after careful confirmation of severity	IIa	IIa
Truly asymptomatic severe AS (no symptoms during treadmill test, no risk criteria) with preserved LVEF if the surgical risk is deemed low and the following criteria are also satisfied: Very severe AS (maximal velocity ≥ 5.5 m/s); Severe valvular calcification and increased maximal velocity by ≥ 0.3 m/s per year	IIa	IIa for velocity ≥ 5 m/s (see text)	AHA/ACC guideline: Velocity ≥ 5 m/s or mean gradient ≥ 60 mmHg AND severe calcifications; velocity 4 to 4.9 m/s or mean gradient 40 to 59 mmHg AND severe valvular calcification AND stress test demonstrating reduced tolerance or drop in blood pressure
		IIb for maximal velocity increase by ≥ 0.3 m/s per year
Truly asymptomatic severe AS (no symptoms during treadmill test, no risk criteria) with preserved LVEF if the surgical risk is deemed low and 1 or more of the following criteria are also satisfied: Severely increased BNP/Nt-ProBNP levels at serial determinations and without an alternative explanation; increased transaortic pressure gradient at stress echocardiography by > 20 mmHg; excessive LV hypertrophy without an alternative explanation	IIb	-	This indication is not covered in the AHA/ACC guidelines
Low-flow/low-gradient/low-LVEF severe AS without contractile/flow reserve	IIb	-	This indication is not covered in the AHA/ACC guidelines

Class I: It is indicated, it is recommended; Class IIa: Should be considered, it is reasonable; Class IIb: May be considered; Class III: It is not indicated, it is contraindicated; ESC: European Society of Cardiology; EACTS: European Association for Cardio-Thoracic Surgery; AHA/ACC: American Heart Association/American College of Cardiology; AS: Aortic stenosis; LVEF: Left ventricular ejection fraction; CABG: Coronary artery bypass graft.

Table 3 Suggested high-risk criteria in asymptomatic severe aortic stenosis

Test	High risk criteria
Electrocardiogram	Presence of LV hypertrophy with secondary ST segment deviation ("LV strain")
Blood tests	Highly increased BNP/Nt-ProBNP levels
Stress test	Unmasked symptoms: Fatigability/dyspnea at < 75 W, syncope/near syncope; angina
	Lack of increase in systolic blood pressure by > 20 mmHg (or decrease) with exercise
	Inducible myocardial ischemia (ST segment depression ≥ 2 mm)
	Severe ventricular arrhythmias (sustained VT, polymorphic VT, VF)
Conventional Doppler echocardiography	Very severe AS (AVA ≤ 0.6 cm; maximal velocity ≥ 5 m/s)
	LVEF < 50%
	Severe LV hypertrophy (≥ 15 mm)?
	Reduced LV longitudinal strain
	Zva ≥ 4.5 mmHg/mL per square meters
Dobutamine stress echocardiography (in low-flow, low-gradient, low LVEF)	Lack of contractile reserve
Exercise echocardiography (ergometric bicycle) - any severe AS	Increase in transvalvular pressure gradient by > 20 mmHg during exercise
	Inducible pulmonary hypertension during exercise (systolic pulmonary pressure ≥ 60 mmHg)
Documentation of valvular calcification	Presence of severe valvular calcifications: Qualitatively (radiology, conventional echocardiography); quantitatively (computed tomography): Calcium score ≥ 1651 Agatston units (lower in women vs men)

LVEF: Left ventricular ejection fraction; AS: Aortic stenosis; AVA: Aortic valve area.

Table 4 Criteria for the diagnosis of severe aortic regurgitation

	Mild AR	Moderate AR	Severe AR
Ratio between the AR jet diameter and the LVOT diameter	< 25%	25%-64%	≥ 65%
Vena contracta (mm)	< 3	3-5.9	≥ 6
Regurgitant volume (mL/beat)	< 30	30-59	≥ 60
Regurgitant fraction	< 30%	30%-49%	≥ 50%
EROA (cm2)	< 0.1	0.1-0.29	≥ 0.3
Diastolic backflow in the descending thoracic and/or abdominal aorta	Minimal	Less than holodiastolic	Holodiastolic (especially for backflow documented in the abdominal aorta)
Angiographic	1+	2+	3-4+
LV dilatation	No	No	Yes (mandatory for chronic severe AR)

AR: Aortic regurgitation; LVOT: Left ventricular outflow tract; EROA: Effective regurgitant orifice area.

Table 5 Indications for aortic valve replacement in chronic aortic regurgitation[33,34]

Criteria	Class of indication		Differences between guidelines
	ESC/EACTS	AHA/ACC
Symptomatic severe AR (any LVEF)	I	I
Asymptomatic severe AR with depressed LV function (LVEF < 50%)	I	I
Severe AR in patients with another indication for cardiac surgery (e.g., CABG, thoracic aorta, another valve)	I	I
Asymptomatic severe AR with normal LVEF (> 50%) but with severe LV dilatation	IIa	IIa	Definition of severe LV dilatation: ESC/EACTS guideline: End-diastolic LV diameter > 70 mm, or end-systolic LV diameter > 50 mm (or > 25 mm/m2); AHA/ACC guidelines: End-systolic LV diameter > 50 mm
Moderate AR in patients with another indication for cardiac surgery (e.g., coronary bypass, thoracic aorta, another valve)	-	IIa	This indication is not covered in the ESC/EACTS guidelines
Severe AR with normal LVEF (> 50%) but with progressive LV dilatation (end-diastolic LV diameter > 65 mm) if the surgical risk is low	-	IIb	This indication is not covered in the ESC/EACTS guidelines

Class I: It is indicated, it is recommended; Class IIa: Should be considered, it is reasonable; Class IIb: May be considered; it is contraindicated; ESC/EACTS: European Society of Cardiology/European Association for Cardio-Thoracic Surgery; AHA/ACC: American Heart Association/American College of Cardiology; AR: Aortic regurgitation; LVEF: Left ventricular ejection fraction; CABG: Coronary artery bypass graft.

Table 6 Indication for surgery in patients with bicuspid aortic valve and aortic root disease[33,34,66,67]

Class of indication	Guideline		Differences between guidelines
	ESC/ EACTS 2012	AHA/ACC 2016 Consensus on AHA/ACC 2014, and ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM 2010 Guidelines
I	-	Asymptomatic bicuspid aortic valve with dilatation of Valsalva sinuses or the ascending thoracic aortic diameter > 55 mm	No class I indications in the 2012 ESC/EACTS guidelines
IIa	Bicuspid aortic valve with an ascending thoracic aortic diameter > 50 mm if the patient also has at least one of the followings: Family history of aortic dissection; documented increase in the aortic diameter > 2 mm/yr (assessed using the same imaging method, at the same level, and with comparative images available); arterial hypertension; coarctation of the aorta	Bicuspid aortic valve AND dilatation of the Valsalva sinuses or of the ascending thoracic aorta (> 50 mm) AND at least one of the following
		Family history of aortic dissection
		Documented increase in aortic diameter > 5 mm/yr
		OR low surgical risk in an expert center
	-	Replacement of the ascending aorta if the patient also has an indication for surgery for AS/AR, and the ascending aortic/Valsalva sinus diameter is > 45 mm	Not covered by the 2012 ESC guidelines

Class I: It is indicated, it is recommended; Class IIa: Should be considered, it is reasonable; Class IIb: May be considered; ESC: European Society of Cardiology; EACTS: European Association for Cardio-Thoracic Surgery; AHA/ACC: American Heart Association/American College of Cardiology; ACCF: American College of Cardiology Foundation; AHA: American Heart Association Task Force on Practice Guidelines; AATS: American Association for Thoracic Surgery; ACR: American College of Radiology; ASA: American Stroke Association; SCA: Society of Cardiovascular Anesthesiologists; SCAI: Society for Cardiovascular Angiography and Interventions; SIR: Society of Interventional Radiology; STS: Society of Thoracic Surgeons; SVM: Society for Vascular Medicine, North American Society for Cardiovascular Imaging; AR: Aortic regurgitation; AS: Aortic stenosis.