Prosthetic Valves and Infective Endocarditis

Prosthetic Valves

-mechanical valve if pts are younger than 50
           -will need lifelong warfarin anticoagulation (see below). Using direct thrombin inhibitors and factor Xa inhibitors is not rec d/t risk of valve thrombosis.
-bioprosthetic valves if older than 70.  (If they’re somewhere between 50 and 70, then it becomes a discussion)
-bioprosthetic valves usually last ~15 years so we tend not to use those in younger patients as they’ll need a replacement
-after getting a valve, pts will undergo a TTE to document baseline performance. If they have a bioprosthesis, they will need to get a yearly TTE beginning 10 years after surgery
Mechanical valve INR goals (used to be a range, but is now a single number to minimize time pts spend at the low end of the range):
-Aortic (if no risk for VTE) — 2.5
-Mitral, older gen mech aortic valve (ball in cage), or aortic valve with risk factors for VTE — 3.0
-Antiplatelet therapy with low dose ASA is recommended for those with a mechanical prosthesis and for pts with a bioprosthesis.
Infective Endocarditis
RF: implanted devices, advanced age, DM, immunosuppression, IVDU, congenital heart disease, cardiac transplant with valvulopathy
DX by Duke criteria (two major, one major plus three minor, or five minor criteria)
Blood cultures are positive in 90% of IE cases and serologic testing is req in culture negative IE.
We classify prosthetic valve endocarditis based on time from surgery:
-Early (<60d) associated with hospital-acquired microbes like staph aureus
-Intermediate (60-365d) most commonly coag negative staph
-Late (>365d) microbes typically resemble those of native valve endocarditis
Workup:
-BCX (before abx)
-TTE
-then TEE if not TTE not diagnostic, intracardiac device leads are present, or abscess is suspected (Andrew astutely pointed out that new 1st deg AV block may be indicative of an abscess!)
Management:
-ABX (can narrow once you have micro data back) – duration variable
-Early surgery (during hospitalization + before completion of abx) if
-symptomatic HF and valvular dysfunction
-left sided IE c/b fungal infections or high resistant organisms
-complications like annular or aortic abscess, penetrating lesions, or significant heart block
-persistent bacteremia or fevers >5-7d despite appropriate abx therapy
-also considered if pt has recurrent emboli and large (>10mm) left sided vegetation
PPX:
PPX recommended before dental procedures in special populations as below. Usually amoxicillin in the outpatient setting.
-hx of endocarditis
-cardiac transplant with valve regurgitation d/t structurally abnormal valve
-prosthetic valves
-other prosthetic material used for valve repairs (annuloplasty rings or chords)
-congenital heart disease
Author: Juliette Logan, MD