I. INTRODUCTION. The development of prosthetic cardiac valves has greatly altered the natural history of patients with valvular heart disease. There have been many advancements in this technology, from the first valve placed in the descending aorta to treat aortic regurgitation by Hufnagel in 1952 to the current percutaneous options for valve placement and even repair. In this chapter, the valve options, the management and follow-up of patients who have undergone valve replacement, as well as procedural indications and complications will be reviewed.
II. TYPES OF VALVES
Broadly, prosthetic valves are divided into those made of biologic tissue (human cadaveric, porcine, bovine, even equine) and those that are mechanical. Whereas the latter require anticoagulation with warfarin, the former have more finite durability.
b. Single tilting disk (Björk-Shiley, Medtronic-Hall, and Omniscience).
2. Current generation valves (bileaflet disk)
a. St. Jude (Masters, Regent).
b. Sorin Carbomedics.
c. Medtronic (Open Pivot).
d. On-X (CryoLife, Kennesaw, GA).
III. CHOICE OF VALVES
The biggest question when it comes to valve replacement is whether to proceed with a biologic or mechanical prosthesis. Issues that affect this decision include expected shorter durability with biologic valves (which is inversely related to age at implantation—Fig. 8.3) and the need for lifelong anticoagulation with warfarin with mechanical valves (the newer-generation anticoagulation agents are not approved for this indication). The decision must take into account patient preferences as well as surgical risks for the original and potentially subsequent procedures. Survival rates and infection rates appear to be comparable between the two valve types, as does the risk of stroke.
Both the American College of Cardiology/American Heart Association (ACC/AHA) and the European Society of Cardiology/European Association for Cardio-Thoracic Surgery (ESC/EACTS) valve disease guidelines have made recommendations with regard to valve choices (Tables 8.1 and 8.2).
FIGURE 8.2 Mechanical valves. A: Bileaflet mechanical; B: Single leaflet mechanical; C: Ball and Cage Valve. (From Zoghbi WA, Chambers JB, Dumesnil JG, et al. Recommendations for evaluation of prosthetic valves with echocardiography and Doppler ultrasound. J Am Soc Echocardiogr. 2009;22(9):976, with permission.)
FIGURE 8.3 Durability of Carpentier-Edwards (CE) valves, as a function of age at implantation. This is from a series comparing the CE porcine and pericardial valves in the aortic position, indicating the percentage that were free from structural valve deterioration (SVD) depending on age at implantation (80-95 years, 70-80 years, 60-70 years, and less than 60 years). In the age group less than 60 years, there was greater than 30% deterioration at less than 10 years. (Reprinted with permission from Gao G, Wu Y, Grunkemeier GL, et al. Durability of pericardial versus porcine aortic valves. J Am Coll Cardiol. 2004;44[2]:384-388.)
TABLE 8.1 Prosthetic Valve Choice
Recommendations
COR
LOE
Choice of valve intervention and prosthetic valve type should be a shared decision process.
I
C
A bioprosthesis is recommended in patients of any age for whom anticoagulant therapy is contraindicated, cannot be managed appropriately, or is not desired.
I
C
A mechanical prosthesis is reasonable for AVR or MVR in patients <60 yr of age who do not have a contraindication to anticoagulation.
IIa
B
A bioprosthesis is reasonable in patients >70 yr of age.
IIa
B
Either a bioprosthetic or mechanical valve is reasonable in patients between 60 and 70 yr of age.
IIa
B
Replacement of the aortic valve by a pulmonary autograft (the Ross procedure), when performed by an experienced surgeon, may be considered in young patients when VKA anticoagulation is contraindicated or undesirable.
IIb
C
AVR, aortic valve replacement; COR, class of recommendation; LOE, level of evidence; MVR, mitral valve replacement; N/A, not applicable; VKA, vitamin K antagonist.
Nishimura RA, Otto CM, Bonow RO, et al. 2014 AHA/ACC guideline for the management of patients with valvular heart disease. J Am Coll Cardiol. 2014.
TABLE 8.2 The Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS)
Class
Level
A mechanical prosthesis is recommended according to the desire of the informed patient and if there are no contraindications for long-term anticoagulation.
I
C
A mechanical prosthesis is recommended in patients at risk of accelerated structural valve deterioration.
I
C
A mechanical prosthesis is recommended in patients already on anticoagulation as a result of having a mechanical prosthesis in another valve position.
I
C
A mechanical prosthesis should be considered in patients <60 yr for prostheses in the aortic position and <65 yr for prostheses in the mitral position.
IIa
C
A mechanical prosthesis should be considered in patients with a reasonable life expectancy for whom future redo valve surgery would be at high risk.
IIa
C
A mechanical prosthesis may be considered in patients already on long-term anticoagulation due to high risk of thromboembolism.
IIb
C
A bioprosthesis is recommended according to the desire of the informed patient.
I
C
A bioprosthesis is recommended when good-quality anticoagulation is unlikely (compliance problems: not readily available) or contraindicated because of high bleeding risk (prior major bleed, comorbidities, unwillingness, compliance problems, lifestyle, occupation).
I
C
A bioprosthesis is recommended for reoperation for mechanical valve thrombosis despite good long-term anticoagulant control.
I
C
A bioprosthesis should be considered in patients for whom future redo valve surgery would be at low risk.
IIa
C
A bioprosthesis should be considered in young women contemplating pregnancy.
IIa
C
A bioprosthesis should be considered in patients >65 yr for prosthesis in aortic position or >70 yr in mitral position or those with life expectancy lower than the presumed durability of the bioprosthesis.
IIa
C
Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC), European Association for Cardio-Thoracic Surgery (EACTS), Vahanian A, et al. Guidelines on the management of valvular heart disease (version 2012). Eur Heart J. 2012;33:2451-2496.
The guidelines emphasize that valve choice is a shared decision process. If patients cannot be on or refuse to be on warfarin, then a bioprosthesis must be used. Given longer durability, the older the age at implantation (and potentially greater complications of warfarin use with increasing age), the more reasonable is the choice of bioprosthetic valves for all patients older than 70 years of age (>65 years of age for aortic position by ESC/EACTS guidelines). For younger patients (<60 years old), mechanical valves are considered reasonable, barring any contraindication and willingness of patient for anticoagulation with warfarin. ESC/EACTS guidelines use age less than 65 years for prostheses in the mitral position.
If patients are already on long-term anticoagulation with warfarin, a mechanical valve would be reasonable at any age. In patients who have had mechanical valve thrombosis despite appropriate anticoagulation management, reoperation should be with a bioprosthetic valve.
For patients with a small annular size (and not a small body surface area [BSA]), a stentless valve may be considered. These have more optimal hemodynamics and lower gradients. This may help in avoiding patient-prosthesis mismatch (discussed further later in the chapter). There are no definitive data yet suggesting better outcomes with the stentless valves, but hemodynamics are better.
A. Transcatheter valves. At present, these valves can be considered for patients who are at least at intermediate risk for traditional surgical aortic valve replacement (AVR). It is a class I recommendation to proceed with transcatheter aortic valve replacement (TAVR) if surgical risk is deemed prohibitive. For those considered high risk, it is a class IIa recommendation. More recent trial data would suggest TAVR may be extended to intermediate-risk patients. Decisions are best made with a Heart Team approach, with evaluation by both cardiac surgery and interventional cardiology.
B. Ross procedure. Guidelines suggest that this procedure can be considered in young patients in whom anticoagulation is undesirable, provided it is performed by a surgeon with considerable experience/expertise with this technique.
A. All patients with mechanical valves require therapy with warfarin. ACC/AHA guidelines recommend an international normalized ratio (INR) goal of 3.0 (±0.5) for mechanical mitral valves, along with aspirin (75 to 100 mg).
B. For mechanical aortic valves in the context of atrial fibrillation, prior thromboembolic events, left ventricular (LV) dysfunction, or hypercoagulable condition (or older-generation ball-cage valves or older-generation single tilting disk valves), the INR goal is the same as above. For mechanical aortic valves without the above risk factors, the INR goal is 2.5 (±0.5) along with a daily aspirin (acetylsalicylic acid [ASA]). The above are all class I indications.
C. For bioprosthetic valves in the mitral position, warfarin is considered reasonable for the first 3 months with an INR goal of 2.5 (±0.5), with long-term daily ASA use (75 to 100 mg). These are listed as class IIa indications. For bioprosthetic valves in the aortic position, warfarin may also be reasonable for the first 3 months with an INR goal of 2.5 (±0.5), this being a class IIb recommendation. Long-term ASA use (75 to 100 mg) is a class IIa indication.
D. Following the placement of a transcatheter valve, clopidogrel 75 mg is recommended for the first 6 months along with long-term ASA (75 to 100 mg).
V. PROSTHETIC VALVE PHYSICAL EXAMINATION
Normally functioning bioprosthetic and mechanical valves can produce murmurs related to the mild physiologic transvalvular gradients. An early-peaking systolic ejection murmur can be expected across most aortic valves (may be absent in homograft valves or stentless valves). Likewise, a brief and low-grade apical diastolic rumble can be heard with normally functioning mitral valves. With development of stenosis, the murmurs do become more prominent and consistent with the examination in native valve stenosis. Bioprosthetic valves should result in normal S1, S2 sounds. The older-generation caged-ball mechanical valves do produce prominent opening and closing clicks. The newer-generation valves have prominent closing clicks. The physiologic regurgitation present on mechanical valves is usually not audible, and any audible regurgitation on a bioprosthetic valve is abnormal. Severity can be assessed as in native valve regurgitation.
VI. ECHOCARDIOGRAPHY
A. Echocardiography remains the primary method by which routine prosthetic valvular assessment is performed. Two-dimensional imaging (whether transthoracic echocardiography [TTE] or transesophageal echocardiography [TEE]) can identify structural abnormalities of the valves (such as thickening/calcification of bioprosthetic leaflets; mobile lesions, which could represent endocarditis; thrombus; and impaired mechanical leaflet motion). Excessive motion of the prosthesis can be identified. Assessment of chamber sizes and function may also provide clues to occult valvular dysfunction.
B. Doppler measurements of transvalvular gradients are paramount in the assessment of prosthetic valve function. What is considered a normal or acceptable gradient depends on valve size, valve type, and position. Cardiac output and heart rate also influence transvalvular gradients. There are published guidelines for expected valve gradients and EOA for each valve type. An important caveat is that these gradients are based on the setting of normal LV function. With depressed LV function, significant prosthetic stenosis can exist when gradients are still in “normal range.” Assessment of flow profile, EOA, and dimensionless index (DI) as described later in this chapter will help to diagnose valvular dysfunction.
Nishimura RA, Otto CM, Bonow RO, et al. 2014 AHA/ACC guideline for the management of patients with valvular heart disease. J Am Coll Cardiol. 2014.
C. It is important to have a baseline echocardiographic assessment of any prosthetic valve after implantation (generally performed at the 4- to 6-week point, when postoperative anemia has resolved). This will then serve as a comparison for follow-up studies in any individual patient (whereas published tables can provide expected values, this will provide the true baseline for any given valve in that particular patient).
D. Unless there is a change in symptoms or examination, echocardiography within the first few years after bioprosthetic valve implantation is generally not necessary after the baseline study. After 5-10 years (especially in younger people), yearly echocardiography would seem reasonable.
1. Gradients: Although expected range of values as in the tables (Tables 8.3 and 8.4) should be referenced, as a general rule the mean gradients for normally functioning aortic prosthesis (and normal LV function/forward flow) are less than 20 mm Hg. A mean gradient of >35 mm Hg is concerning for significant stenosis (in the absence of increased flow).
Likewise, a normally functioning mitral prosthesis has a mean gradient of 5 mm Hg or less. Greater than 10 mm Hg is concerning for stenosis.
TABLE 8.3 Normal Prosthetic Aortic Valve Gradients
Valve
Size
Peak Gradient (mm Hg)
Mean Gradient (mm Hg)
Effective Orifice Area (cm2)
ATS
Bileaflet
19
21
23
25
27
29
47.0 ± 12.6
23.7 ± 6.8
25.3 ± 8.0
15.9 ± 5.0
14.4 ± 4.9
11.3 ± 3.7
8.4 ± 3.7
8.0 ± 3.0
1.1 ± 0.3
1.4 ± 0.5
1.7 ± 0.5
2.1 ± 0.7
2.5 ± 0.1
3.1 ± 0.8
ATS AP
18
21.0 ± 1.8
1.2 ± 0.3
Bileaflet
20
22
24
26
21.4 ± 4.2
18.7 ± 8.3
15.1 ± 5.6
11.1 ± 3.5
10.5 ± 4.5
7.5 ± 3.1
6.0 ± 2.0
1.3 ± 0.3
1.7 ± 0.4
2.0 ± 0.6
2.1 ± 0.4
Baxter Perimount
Stented bovine pericardial
19
21
23
25
27
32.5 ± 8.5
24.9 ± 7.7
19.9 ± 7.4
16.5 ± 7.8
12.8 ± 5.4
19.5 ± 5.5
13.8 ± 4.0
11.5 ± 3.9
10.7 ± 3.8
4.8 ± 2.2
1.3 ± 0.2
1.3 ± 0.3
1.6 ± 0.3
1.6 ± 0.4
2.0 ± 0.4
Biocor
Stented porcine
23
25
27
30.0 ± 10.7
23.0 ± 7.9
22.0 ± 6.5
20 ± 6.6
16 ± 5.1
15.0 ± 3.7
1.3 ± 0.3
1.7 ± 0.4
2.2 ± 0.4
Extended Biocor
Stentless
19-21
23
25
17.5 ± 6.5
14.7 ± 7.3
14.0 ± 4.3
9.6 ± 3.6
7.7 ± 3.8
7.4 ± 2.5
1.4 ± 0.4
1.7 ± 0.4
1.8 ± 0.4
BioFlo
Stented bovine pericardial
19
21
37.2 ± 8.8
28.7 ± 6.2
26.4 ± 5.5
18.7 ± 5.5
0.7 ± 0.1
1.1 ± 0.1
Björk-Shiley
Single tilting disk
21
23
25
27
38.9 ± 11.9
28.8 ± 11.2
23.7 ± 8.2
21.8 ± 3.4
15.7 ± 5.3
13.0 ± 5.0
10.0 ± 2.0
1.1 ± 0.3
1.3 ± 0.3
1.5 ± 0.4
1.6 ± 0.3
Carbomedics Reduced
Bileaflet
19
43.4 ± 12
24.4 ± 1.2
1.2 ± 0.1
Carbomedics Standard
Bileaflet
19
21
23
25
27
29
38.0 ± 12.8
26.8 ± 10.1
22.5 ± 7.4
19.6 ± 7.8
17.5 ± 7.1
9.1 ± 4.7
18.9 ± 8.3
12.9 ± 5.4
11.0 ± 4.6
9.1 ± 3.5
7.9 ± 3.2
5.6 ± 3.0
1.0 ± 0.3
1.5 ± 0.4
1.4 ± 0.3
1.8 ± 0.4
2.2 ± 0.2
3.2 ± 1.6
Carbomedics Top Hat
Bileaflet
21
23
25
30.2 ± 10.9
24.2 ± 7.6
14.9 ± 5.4
12.5 ± 4.4
9.5 ± 2.9
1.2 ± 0.3
1.4 ± 0.4
1.6 ± 0.32
Carpentier-Edwards Pericardial
Stented bovine pericardial
19
21
23
25
32.1 ± 3.4
25.7 ± 9.9
21.7 ± 8.6
16.5 ± 5.4
24.2 ± 8.6
20.3 ± 9.1
13.0 ± 5.3
9.0 ± 2.3
1.2 ± 0.3
1.5 ± 0.4
1.8 ± 0.3
Carpentier-Edwards Standard
Stented porcine
19
21
23
25
27
29
43.5 ± 12.7
27.7 ± 7.6
28.9 ± 7.5
24.0 ± 7.1
22.1 ± 8.2
25.6 ± 8.0
17.3 ± 62
16.1 ± 6.2
12.9 ± 4.6
12.1 ± 5.5
9.9 ± 2.9
0.9 ± 0.2
1.5 ± 0.3
1.7 ± 0.5
1.9 ± 0.5
2.3 ± 0.6
2.8 ± 0.5
Carpentier Supra-annular
19
34.1 ± 2.7
1.1 ± 0.1
21
28.0 ± 10.5
17.5 ± 3.8
1.4 ± 0.9
Stented porcine
23
25
27
25.3 ± 10.5
24.4 ± 7.6
16.7 ± 4.7
13.4 ± 4.5
13.2 ± 4.8
8.8 ± 2.8
1.6 ± 0.6
1.8 ± 0.4
1.9 ± 0.7
Cryolife
Stentless
19
21
23
25
27
9.0 ± 2.0
6.6 ± 2.9
6.0 ± 2.3
6.1 ± 2.6
4.0 ± 2.4
1.5 ± 0.3
1.7 ± 0.4
2.3 ± 0.2
2.6 ± 0.2
2.8 ± 0.3
Edwards Duromedics
Bileaflet
21
23
25
27
39.0 ± 13
32.0 ± 8.0
26.0 ± 10.0
24.0 ± 10.0
Edwards Mira
Bileaflet
19
21
23
25
18.2 ± 5.3
13.3 ± 4.3
14.7 ± 2.8
13.1 ± 3.8
1.2 ± 0.4
1.6 ± 0.4
1.6 ± 0.6
1.9
Hancock
Stented porcine
21
23
25
18.0 ± 6.0
16.0 ± 2.0
15.0 ± 3.0
12.0 ± 2.0
11.0 ± 2.0
10.0 ± 3.0
Hancock II
21
14.8 ± 4.1
1.3 ± 0.4
Stented porcine
23
25
29
34.0 ± 13.0
22.0 ± 5.3
16.2 ± 1.5
16.6 ± 8.5
10.8 ± 2.8
8.2 ± 1.7
1.3 ± 0.4
1.6 ± 0.4
1.6 ± 0.2
Homograft
17-19
9.7 ± 4.2
4.2 ± 1.8
Homograft valves
19-21
5.4 ± 0.9
20-21
20-22
7.9 ± 4.0
7.2 ± 3.0
3.6 ± 2.0
3.5 ± 1.5
22
1.7 ± 0.3
5.8 ± 3.2
22-23
22-24
5.6 ± 3.1
2.6 ± 1.4
5.6 ± 1.7
24-27
6.2 ± 2.6
2.8 ± 1.1
26
25-28
1.4 ± 0.6
6.8 ± 2.9
6.2 ± 2.5
Intact
19
40.4 ± 15.4
24.5 ± 9.3
Stented porcine
21
23
25
27
40.9 ± 15.6
32.7 ± 9.6
29.7 ± 15.0
25.0 ± 7.5
19.6 ± 8.1
19.0 ± 6.1
17.7 ± 7.9
15.0 ± 4.5
1.6 ± 0.4
1.6 ± 0.4
1.7 ± 0.3
Ionescu-Shiley
17
23.8 ± 3.4
0.9 ± 0.1
Stented bovine pericardial
19
21
19.7 ± 5.9
26.6 ± 9.0
13.3 ± 3.9
1.1 ± 0.1
23
15.6 ± 4.4
Labcor-Santiago
Stented bovine pericardial
19
21
23
25
18.6 ± 5.0
17.5 ± 6.6
14.8 ± 5.2
12.3 ± 3.4
11.8 ± 3.3
8.2 ± 4.5
7.8 ± 2.9
6.8 ± 2.0
1.2 ± 0.1
1.3 ± 0.1
1.8 ± 0.2
2.1 ± 0.3
Labcor Synergy
Stented porcine
21
23
25
27
24.3 ± 8.1
27.3 ± 13.7
22.5 ± 11.9
17.8 ± 7.0
13.3 ± 4.2
15.3 ± 6.9
13.2 ± 6.4
10.6 ± 4.6
1.1 ± 0.3
1.4 ± 0.4
1.5 ± 0.4
1.8 ± 0.5
MCRI On-X
Bileaflet
19
21
23
25
21.3 ± 10.8
16.4 ± 5.9
15.9 ± 6.4
16.5 ± 10.2
11.8 ± 3.4
9.9 ± 3.6
8.6 ± 3.4
6.9 ± 4.3
1.5 ± 0.2
1.7 ± 0.4
1.9 ± 0.6
2.4 ± 0.6
Medtronic Advantage
Bileaflet
23
25
27
29
10.4 ± 3.1
9.0 ± 3.7
7.6 ± 3.6
6.1 ± 3.8
2.2 ± 0.3
2.8 ± 0.6
3.3 ± 0.7
3.9 ± 0.7
Medtronic Freestyle
19
13.0 ± 3.9
Stentless
21
9.1 ± 5.1
1.4 ± 0.3
23
25
27
11.0 ± 4.0
8.1 ± 4.6
5.3 ± 3.1
4.6 ± 3.1
1.7 ± 0.5
2.1 ± 0.5
2.5 ± 0.1
Medtronic-Hall
Single tilting disk
20
21
23
25
27
34.4 ± 13.1
26.9 ± 10.5
26.9 ± 8.9
17.1 ± 7.0
18.9 ± 9.7
17.1 ± 5.3
14.1 ± 5.9
13.5 ± 4.8
9.5 ± 4.3
8.7 ± 5.6
1.2 ± 0.5
1.1 ± 0.2
1.4 ± 0.4
1.5 ± 0.5
1.9 ± 0.2
Medtronic Mosaic
21
14.2 ± 5.0
1.4 ± 0.4
Stented porcine
23
25
27
29
23.8 ± 11.0
22.5 ± 10.0
13.7 ± 4.8
11.7 ± 5.1
10.4 ± 4.3
11.1 ± 4.3
1.5 ± 0.4
1.8 ± 0.5
1.9 ± 0.1
2.1 ± 0.2
Mitroflow
Stented bovine pericardial
19
18.6 ± 5.3
13.1 ± 3.3
1.1 ± 0.2
Monostrut Bjork-Shiley
19
27.4 ± 8.8
21
27.5 ± 3.1
20.5 ± 6.2
Single tilting disk
23
25
27
20.3 ± 0.7
17.4 ± 6.4
16.1 ± 4.9
11.4 ± 3.8
Prima
Stentless
21
23
25
28.8 ± 6.0
21.5 ± 7.5
22.1 ± 12.5
13.7 ± 1.9
11.5 ± 4.9
11.6 ± 7.2
1.4 ± 0.7
1.5 ± 0.3
1.8 ± 0.5
Omnicarbon
Single tilting disk
21
23
25
27
37.4 ± 12.8
28.8 ± 9.1
23.7 ± 8.1
20.1 ± 4.2
20.4 ± 5.4
17.4 ± 4.9
13.2 ± 4.6
12.4 ± 2.9
1.3 ± 0.5
1.5 ± 0.3
1.9 ± 0.5
2.1 ± 0.4
Omniscience
Single tilting disk
21
23
50.8 ± 2.8
39.8 ± 8.7
28.2 ± 2.2
20.1 ± 5.1
0.9 ± 0.1
1.0 ± 0.1
Starr-Edwards
Caged ball
23
24
26
27
29
32.6 ± 12.8
34.1 ± 10.3
31.8 ± 9.0
30.8 ± 6.3
29.0 ± 9.3
22.0 ± 9.0
22.1 ± 7.5
19.7 ± 6.1
18.5 ± 3.7
16.3 ± 5.5
1.1 ± 0.2
1.1 ± 0.3
Sorin Bicarbon
Bileaflet
19
21
23
25
30.1 ± 4.5
22.0 ± 7.1
16.8 ± 6.1
11.2 ± 3.1
16.7 ± 2.0
10.0 ± 3.3
7.7 ± 3.3
5.6 ± 1.6
1.4 ± 0.1
1.2 ± 0.4
1.5 ± 0.2
2.4 ± 0.3
Sorin Pericarbon
Stentless
19
21
23
36.5 ± 9.0
28.0 ± 13.3
27.5 ± 11.5
28.9 ± 7.3
23.8 ± 11.1
23.2 ± 7.6
1.2 ± 0.5
1.3 ± 0.6
1.5 ± 0.5
St. Jude Medical Haem Plus
Bileaflet
19
21
23
28.5 ± 10.7
16.3 ± 17.0
16.8 ± 7.3
17.0 ± 7.8
10.6 ± 5.1
12.1 ± 4.2
1.9 ± 0.1
1.8 ± 0.5
1.7 ± 0.5
St. Jude Medical Regent
Bileaflet
19
21
23
25
27
20.6 ± 12
15.6 ± 9.4
12.8 ± 6.8
11.7 ± 6.8
7.9 ± 5.5
11.0 ± 4.9
8.0 ± 4.8
6.9 ± 3.5
5.6 ± 3.2
3.5 ± 1.7
1.6 ± 0.4
2.0 ± 0.7
2.3 ± 0.9
2.5 ± 0.8
3.6 ± 0.5
St. Jude Medical Standard
Bileaflet
19
21
23
25
27
29
42.0 ± 10.0
25.7 ± 9.5
21.8 ± 7.5
18.9 ± 7.3
13.7 ± 4.2
13.5 ± 5.8
24.5 ± 5.8
15.2 ± 5.0
13.4 ± 5.6
11.0 ± 5.3
8.4 ± 3.4
7.0 ± 1.7
1.5 ± 0.1
1.4 ± 0.4
1.6 ± 0.4
1.9 ± 0.5
2.5 ± 0.4
2.8 ± 0.5
St. Jude Medical
Stentless
21
23
25
27
29
22.6 ± 14.5
16.2 ± 9.0
12.7 ± 8.2
10.1 ± 5.8
7.7 ± 4.4
10.7 ± 7.2
8.2 ± 4.7
6.3 ± 4.1
5.0 ± 2.9
4.1 ± 2.4
1.3 ± 0.6
1.6 ± 0.6
1.8 ± 0.5
2.0 ± 0.3
2.4 ± 0.6
Zoghbi WA, Chambers JB, Dumesnil JG, et al. Recommendations for evaluation of prosthetic valves with echocardiography and Doppler ultrasound: a report from the American Society of Echocardiography’s Guidelines and Standards Committee and the Task Force on Prosthetic Valves. J Am Soc Echocardiogr. 2009;22:975-1014.
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