B P8 C79 Prosthetic Heart Valves

Question 1

There are three basic types of mechanical prosthetic valves:

Answer 1

Bileaflet
Tilting disc
Ball-cage

Question 2

The _____ valve is the most frequently implanted mechanical prosthesis worldwide.

Answer 2

St. Jude bileaflet valve

It consists of two pyrolytic semi-circular “leaflets” or discs with a slit-like central orifice between the two leaflets and two larger semi-circular orifices laterally. The opening angle of the leaflets relative to the annulus plane ranges from 75 to 90 degree

Question 3

For a given valve annulus size, the effective orifice areas (EOAs) are generally _____ and transprosthetic pressure gradients are _____ for the bileaflet mechanical valves compared with the tilting disc valves

Answer 3

EOA: Larger
Transprosthetic PG: Lower

Question 4

Because the central orifice is _____ than the lateral orifices in bileaflet valves, the blood flow velocity may be locally higher within the inflow aspect of the central orifice; this phenomenon may yield to _____ of gradient and _____ of EOA by transthoracic echocardiography (TTE)

Answer 4

Smaller - central orifice

Overestimation - gradient

Underestimation: EOA

Question 5

Bileaflet valves typically have a small amount of normal _____ designed in part to decrease the risk of thrombus formation.

A small central jet and two converging jets emanating from the hinge points of the disc can be visualized on color Doppler flow imaging.

Answer 5

Regurgitation (“washing jet”)

Question 6

_____ valves use a single circular disc that rotates within a rigid annulus to occlude or open the valve orifice. The disc is secured by lateral or central metal struts.

The opening angle of the disc relative to the valve annulus ranges from 60 to 80 degrees, resulting in two orifices of different size.The nonperpendicular opening angle of the valve occluder tends to slightly increase the resistance to bloodflow, particularly in the major orifices.

Answer 6

Tilting disc or monoleaflet valve

Tilting disc valves also have a small amount of regurgitation, arising from small gaps at the perimeter of the valve.

Question 7

The bulky Starr-Edwards ______ valve, the oldest commercially available prosthetic heart valve first used in 1965, is no longer implanted.

Answer 7

Ball-cage valve

The ball-cage valve is more thrombogenic and has less favorable hemodynamic performance characteristics than either bileaflet or tilting disc valves.

Question 8

Currently available mechanical valves have excellent long-term durability, with up to ____ years for the Starr-Edwards valve and more than ___ years for the St. Jude valve

Answer 8

Starr-Edwards: 45 years

St. Jude: > 35 years

Question 9

All patients with mechanical valves require lifelong _____.

Answer 9

Anticoagulation with a VKA

Question 10

Long-term issues associated with mechanical valves include _____.

Answer 10

Infective endocarditis
Paravalvular leaks
Hemolytic anemia
Valve thrombosis/thromboembolism
Pannus in-growth
Hemorrhagic complications related to anticoagulation

Question 11

Tissue or biological valves include stented and stentless bioprostheses (porcine, bovine), homografts (or allografts) from human cadaveric sources, and autografts of pericardial or pulmonic valve origin.

They provide an alternative, less _____ heart valve substitute for which long-term anticoagulation in the absence of additional risk factors for thromboembolism is not required.

Answer 11

Less thrombogenic

Question 12

Types of tissue valves

Answer 12

Stented bioprosthetic valves
Stentless bioprosthetic valves
Homografts
Autografts
Transcatheter bioprosthetic valves

Question 13

Two main types of transcatheter aortic valves are currently used: balloon-expandable valves (BEV) and self-expanding valves (SEV)

The choice of SEV versus BEV is highly operator dependent, though there are anatomic and echocardiographic considerations to be taken into account.

Intermediate term durability appears similar, though the risk of permanent pacemaker implantation is higher with _______

Answer 13

SEVs

Question 14

Leaflet thrombosis can be recognized by the appearance of ____ on ECG-gated computed tomography (CT) and occurs in 10% to 20% of patients 30 days after TAVR, compared with approximately 5% to 15% after surgical AVR (SAVR).

______, that is HALT in the absence of thromboembolic complications or a progressive increase in the transvalvular gradient

For a given aortic annulus size, TAVR valves often have larger EOAs, lower gradients, and lower incidence of severe ____ compared with SAVR valves.

______ is, however, more frequent following TAVR and may result in adverse long-term consequences depending on its severity.

Answer 14

Hypoattenuated leaflet thickening (HALT)

Subclinical leaflet thrombosis

Prosthesis-patient mismatch

Paravalvular leak (PVL)

Question 15

All patients with mechanical heart valves require lifelong anticoagulation with a VKA, the intensity of which varies as a function of _____.

Answer 15

• Valve type or thrombogenicity
• Valve position and number
• Presence of additional risk factors for thromboembolism, such as AF, LV systolic dysfunction, a history of thromboembolism,and hypercoagulable state

Question 16

Anticoagulant therapy with non-vitamin K oral anticoagulants (NOACs) should not be used in patients with _____, although they can be used in patients with bioprosthetic valves or annuloplasty rings at a distance from surgery

Answer 16

Mechanical prostheses

Question 17

The addition of _____ to VKA therapy can be considered in patients with mechanical valves when dictated by another indication.

Answer 17

Low-dose aspirin

Question 18

Although there is no clear consensus, a VKA may be used even in the absence of risk factors for thromboembolism for the first _____ months after bioprosthetic AVR or MVR

Answer 18

3-6 months

Question 19

Longer-term treatment of low thromboembolic risk bioprosthetic AVR and MVR patients consists of _____, although there are no randomized data to support this practice

Answer 19

Low-dose aspirin

Question 20

In the absence of an indication for anticoagulation, single-agent antiplatelet therapy with _____ is reasonable after TAVR

Answer 20

Low-dose aspirin

Question 21

For patients with an indication for anticoagulation, monotherapy with either a _____ is reasonable after TAVR

Answer 21

VKA or NOAC

Question 22

Treatment following TAVR with _____ is contraindicated

Answer 22

Low-dose rivaroxaban (10 mg daily) plus aspirin (75 to 100 mg daily for the first 3 months)

Question 23

Low-risk patients with low-profile bileaflet or tilting disc valves in the aortic position can usually stop VKA therapy _____ days before noncardiac surgery and then resume it postoperatively as soon as it is considered safe, without the need for a heparin “bridge.”

In all other patients, either _____ should be given on an individualized basis both before and after surgery, as directed by the surgeon.

Answer 23

3 to 5 days

LMWH or UFH

The use of LMWH avoids the need for preoperative hospitalization.

Question 24

For patients with a _____ receiving an anticoagulant, it is reasonable to consider the need for bridging on the basis of the CHA2DS2-VASc score and the risk of bleeding

Answer 24

Bioprosthetic valve or annuloplasty ring

Question 25

Pregnant patients with prosthetic valves should be followed carefully because of the increased _____ that can cause or worsen heart failure if there is prosthetic valve dysfunction and also because of the _____ state related to pregnancy that increases the risk of valve thrombosis.

Answer 25

Increased hemodynamic burden

Hypercoagulable state

Question 26

_____ antithrombotic regimens carry an increased risk to the fetus, an increased risk of miscarriage, and an increased risk of hemorrhagic complications for the mother.

Hence, patients require appropriate counseling, close monitoring, and adjustment of anticoagulation therapy

Answer 26

All antithrombotic regimens

Question 27

In pregnant patients with mechanical valves, warfarin is reasonable in the first trimester if the dose is ≤_____ mg/day and is recommended to achieve a therapeutic international normalized ratio (INR) target in the second and third trimesters.

_____ is recommended before planned vaginal delivery in pregnant patients with a mechanical valve.

Answer 27

≤ 5 mg/day - reasonable in 1T, tatget INR at 2T and 3T

Discontinuation of warfarin with initiation of intravenous UFH - before planned vaginal delivery (Mechanical valve)

Question 28

Patients with prosthetic valves are at increased risk for infective endocarditis because of the _____.

Answer 28

Foreign valve surface and sewing ring

Question 29

Antibiotic prophylaxis is indicated for patients with prosthetic valves who undergo _____, and it is not recommended for non-dental procedures such as TEE, EGD, colonoscopy, or cystoscopy (unless there is active infection in these areas)

Answer 29

Dental procedures that involve manipulation of gingival tissue, the periapical region of teeth, or perforation of the oral mucosa

Question 30

Postoperative visits should begin approximately _____ weeks after valve implantation.

The first visit is focused on ensuring a smooth transition from hospital/rehabilitation facility to home, reconciling medications, and assessing neurocognitive function, wound healing, volume status, heart rhythm, and the auscultatory characteristics of prosthetic valve function.The history at subsequent visits is tailored to detect symptoms suggestive of heart failure or reduced functional capacity, arrhythmia, thromboembolism, or infection

Answer 30

3 to 4 weks

Question 31

After the 6-month mark, follow-up visits can be conducted _____ unless interim problems arise.

Answer 31

Annually

Question 32

A chest radiograph is obtained by the surgeon at the first visit to assess for _____.

An electrocardiogram is routinely performed and should be reviewed for _____.

Postoperative baseline values for hemoglobin, hematocrit, lactate dehydrogenase (LDH), and bilirubin should be established for patients with mechanical heart valves, allowing future comparisons should hemolysis be suspected.

Answer 32

CXR:
Residual pleural fluid
Pneumothorax
Lung aeration
Heart size

ECG:
Rhythm, conduction, and dynamic repolarization changes

Question 33

An initial TTE examination performed ____ weeks to ____ months after prosthetic valve implantation is recommended to assess the results of surgery and serve as a baseline for comparison should complications or deterioration occur later

Answer 33

6 weeks to 3 moths

Question 34

Repeat _____ is recommended if there is a change in clinical symptoms or signs suggesting valve dysfunction

Answer 34

TTE (as well as TEE, fluoroscopy, or gated cardiac CT)

Question 35

In patients with a bioprosthetic surgical valve, routine TTE follow-up is recommended at _____ years and then annually thereafter.

Presently, annual TTE studies are recommended for TAVR patients

Studies estimate that 25% to 30% of patients with a bioprosthesis implanted for less than 10 years in the aortic position have some degree of valve degeneration/dysfunction.

Answer 35

5 and 10 years

In patients with mechanical valves, r tine annual echocardiography is not indicated in the absence of a change in clinical status.

Question 36

Paravalvular regurgitation is more common following _____ and the measurement of valve EOA is more challenging in transcatheter valves than in surgical valves due to the presence of the valve stent in the LV outflow tract.

Answer 36

TAVR than SAVR

Question 37

_____ occurs when the size of a normally functioning prosthetic valve is too small in relation to the patient’s body size and thus to the patient’s cardiac output requirements, resulting in abnormally high postoperative gradients.

Answer 37

PPM

The suspicion of prosthetic valve dysfunction may be heightened by the appreciation of a new murmur or symptom in a patient with a prosthetic valve or the incidental finding of abnormally high flow velocities and gradients detected during routine echocardiography.

Prosthetic valve stenosis may be caused by thrombus formation, pannus ingrowth (or a combination of both), leaflet calcification in the case of bioprosthetic valves, and vegetations.

Prosthetic valve regurgitation may be related to thrombus formation (mechanical valves), leaflet tear (bioprostheses), vegetations, or PVL.

Question 38

PPM is defined as an indexed EOA <____ cm2 (severe: _____ cm2) for aortic prosthetic valves and EOA <______ cm2 (severe: <_____ cm2) for mitral prosthetic valves.

Answer 38

Aortic PV: < 0.85 cm2 (Severe: < 0.65 cm2)

Mitral PV: < 1.2 cm2 (Severe: < 0.9 cm2)

The prevalence of moderate PPM ranges from 20% to 70% and that of severe PPM from 2% to 10% following AVR or MVR, respectively.

Question 39

Patients with _____ PPM have higher functional class and worse exercise capacity, reduced regression of LV hypertrophy, more adverse cardiac events, and increased risk of both perioperative and late mortality after SAVR when compared with patients who do not have PPM.

Answer 39

Aortic PPM

A greater clinical impact of aortic PPM is also observed in specific groups of patients such as those with preexisting LV dysfunction or severe LV hypertrophy, and/or concomitant MR, as well as in those <65 to 70 years old.

Question 40

Patients with _____ PPM have persisting pulmonary hypertension and increased incidence of congestive heart failure and death.

Answer 40

Mitral PPM

Question 41

PPM is _____ frequent with TAVR compared with SAVR, particularly in the subset of patients with a small aortic annulus

Answer 41

Less frequent

Question 42

To reduce the incidence of postoperative PPM, _____ is often performed to allow for implantation of a larger prosthesis

Answer 42

Aortic root enlargement

Question 43

SVD due to _____ is the major cause of bioprosthetic valve failure.

Answer 43

Leaflet calcification and/or collagen fiber disruption

Mechanical prostheses have an excellent durability, and SVD is extremely rare with contemporary valves

SVD may lead to leaflet stiffening and progressive stenosis or leaflet tear with transvalvular regurgitation

Question 44

Although SVD of bioprostheses has long been considered a purely passive degenerative process, more recent studies suggest that active and potentially modifiable processes may be involved including _____.

Answer 44

• Lipid infiltration
• Inflammation
• Immune rejection
• Active mineralization

Question 45

PVL occurs external to the prosthetic valve at the interface between the _____.

Answer 45

Valve ring and the native valve annulus

It can occur as a result of inadequate technique, suture dehiscence, compromised native tissue integrity (dense calcification, extensive myxomatous degeneration), infection, or chronic abrasion of the sewing ring against a calcified or rigid annulus

Question 46

The magnitude of the regurgitant volume will depend on the size of the orifice.

A small and hemodynamically inconsequential PVL is usually discovered incidentally during routine TTE with color Doppler flow imaging.

No change in management would be indicated.

Small PVLs may, however, be associated with significant _____ as red blood cells are forced through a narrow orifice at high velocities.

Answer 46

Intravascular hemolysis and anemia

Question 47

Larger PVLs may result in significant _____, to an extent that reoperation or catheter closure with an occluder device might be indicated.

Significant PVL may develop during the late postoperative period and if such is the case, this is often the result of _____.

Management can prove quite challenging and a conservative approach with medical therapy may be chosen.

Answer 47

Volume overload and HF

Endocarditis

Question 48

PVL is more frequent following _____; its incidence is significantly lower with newer generation TAVR bioprostheses.

Because PVL jets after TAVR are often multiple, irregular, and eccentric, the imaging and grading of PVL can be challenging

Answer 48

TAVR compared with SAVR

Question 49

The use of corrective procedures such as repeat _____ may be considered depending on the severity of PVL and the risk of procedural complications.

Answer 49

• Balloon dilation
• Valve-in-valve implantation,
• Transcatheter leak closure

Question 50

______ are a major source of morbidity in patients with prosthetic heart valves.

The incidence of clinically recognizable events ranges from 0.6% to 2.3% per patient-year, an estimate that does not account for any subclinical episodes, which might be detected with sensitive imaging techniques

Answer 50

Thromboembolisms

Question 51

Risk factors for thromboembolism include the:

Answer 51

• Inherent thrombogenicity of the prosthesis
• Valve position (mitral > aortic)
• Valve number
• Time spent out of the therapeutic range of VKA anticoagulation
• History of thromboembolism
• Hypercoagulable state
• Atrial fibrillation
• Left atrial enlargement
• LV systolic dysfunction

Question 52

The risk of bleeding, estimated at _____% per patient-year, increases with age and the intensity of anticoagulation.

In patients with uncontrollable bleeding who require reversal of anticoagulation, administration of _____ is reasonable. Antidotes to oral anti-Xa and antithrombin agents are also available.

Answer 52

1% per patient-year

Prothrombin complex concentrate

Question 53

Management of a thromboembolic event in patients with mechanical valves generally proceeds along one or more of the following lines: _____

Reoperation to implant a less thrombogenic valve is rarely undertaken for patients with recurrent thromboemboli despite aggressive antithrombotic therapy.

Answer 53

(1) For patients whose INR is subtherapeutic, the dose of the VKA is advanced to achieve the intended INR range

(2) For patients whose INR is in the therapeutic range, the dose of the VKA is advanced to achieve a higher INR range and/or low-dose aspirin is added if not already used

(3) The patient and family are informed about the increased risks of bleeding

(4) The potential for drug interactions is reviewed

Question 54

The incidence of mechanical valve thrombosis is estimated at _____% per patient-year in high-income countries, but as high as _____% per patient-year in low- to middle-income countries. Thrombosis of a mechanical heart valve can have devastating consequence

Answer 54

High-income: 0.3% to 1.3%/patient-year
Low-middle income: 6%/patient-year

Bioprosthetic (surgical or trancatheter) valve thrombosis is less common but does occur.

Oral anticoagulation is reasonable for patients with bioprosthetic valve thrombosis and clinical symptoms (thromboembolism) or progressive prosthetic valve gradients with evidence of leaflet dysfunction; a VKA may be preferred.

Question 55

Clinical suspicion of mechanical prosthetic valve thrombosis should be raised by symptoms of _____, coupled with a ______.

Answer 55

• Heart failure
• Thromboembolism
• Low cardiac output

Plus

• Decrease in the intensity of the valve closure sounds
• New and pathologic murmurs
• Documentation of inadequate anticoagulation

Question 56

Thrombosis is more common in the _____ positions than in the aortic position

Answer 56

Mitral and Tricuspid positions

Question 57

Emergency surgery for prosthetic valve thrombosis is reasonable for patients with _____.

Answer 57

• Left-sided mechanical valve thrombosis and shock or NYHA FC III to IV symptoms
• Large thrombus burden (≥0.8 cm2 on TEE)

Question 58

Slow infusion, low-dose fibrinolytic therapy is reasonable for patients with _____

Answer 58

• Recent onset (<2 weeks) NYHA FC I to II symptoms + small thrombus burden (<0.8 cm2)
• Sicker patients with larger thrombi when surgery is either not available or inadvisable.

Fibrinolytic therapy is generally recommended for patients with right- sided prosthetic valve thrombosis

Question 59

Some patients with no or minimal symptoms and small thrombi can often be managed with _____ alone and then converted to _____ if unsuccessful.

Answer 59

IV UFH

Fibrinolytic therapy

Question 60

Any course of fibrinolytic therapy is followed at the appropriate interval by a continuous infusion of _____ during the transition to VKA therapy targeted to a higher INR with or without low-dose aspirin.

Serial TTE studies are useful to assess the response to treatment.

Answer 60

UFH

Question 61

____ is the most severe form of infective endocarditis and occurs in 1% to 6% of patients with valve prostheses accounting for 10% to 30% of all cases of infective endocarditis

PVE after TAVR occurs predominantly within the first year after the procedure. Its incidence is low (0.5% to 1% per patient-year) but in-hospital (∼35%) and 2-year (∼67%) mortality rates are high, likely reflective of patient age and comorbidities.

Answer 61

Prosthetic valve endocarditis (PVE)

PVE is an extremely serious condition with high in-hospital mortality rates (20% to 50%).

TEE is essential in patients with prosthetic valves because of its greater sensitivity in detecting these abnormalities.

Question 62

Increased uptake of _____ measured by positron emission tomography CT (PET-CT) may improve the early diagnosis of PVE.

Answer 62

18Fluorodeoxyglucose

Question 63

Despite prompt and appropriate antibiotic treatment, many patients with PVE will eventually require surgery.

Medical treatment alone is more likely to succeed in _____.

Answer 63

• Late PVE (occurring >6 months after surgery)
• Nonstaphylococcal infections

Question 64

Surgery should be considered in patients with PVE the following situations:

Answer 64

• Heart failure
• Failure of antibiotic treatment
• Hemodynamically significant prosthetic valve regurgitation, especially if associated with deterioration of LV function
• Large vegetations (>10 mm in size)
• Persistently positive blood cultures on therapy
• Recurrent emboli with persistent vegetations
• Intracardiac fistula formation

Question 65

The development of a non-immune hemolytic anemia after valve replacement or repair is usually attributable to _____.

Answer 65

PVL with intravascular red blood cell destruction

Question 66

Diagnosis of hemolytic anemia is based on:

Answer 66

High index of suspicion

PLUS

Laboratory evidence of hemolysis, including:
- Characteristic changes in red blood cells morphology (schistocytes)
- Elevated indirect bilirubin and LDH
- High reticulocyte count
- Depressed serum haptoglobin

Question 67

Management of Hemolytic anemia in patients with prosthetic valves

Reoperative surgery or catheter closure of the defect is indicated when _____ intervenes.

Empiric medical measures include ____. It is important to exclude PVE as a cause.

Answer 67

Reoperative surgery/Catheter closure:
Heart failure
Persistent transfusion requirement
Poor quality of life

Medical:
Iron and folic acid replacement therapy
Beta-adrenoreceptor blockers

Question 68

Evaluation of aortic prosthetic valve stenosis.

Answer 68

Question 69

Evaluation of mitral prosthetic valve stenosis

Answer 69