MOFFITT CARDIOLOGY REPORT PEARLS 9/13/16: Culture-Negative Endocarditis and ECMO!

Thanks to Anna for presenting a super interesting case of a young man with a complex cardiac history found to have prosthetic mitral valve dehiscence and possible culture negative endocarditis!

Pearls below!


Top Pearls:

  • Early paravalvular regurgitation post-valve replacement is common and usually mild.
  • The most common cause of later valve dehiscence is infective endocarditis.


Culture negative endocarditis:

  • Definition: 3 independent bcx remaining negative at 7 days
  • 2-7% of endocarditis cases
  • 3 reasons: prior abx, inadequate culture technique, or fastidious zoonoses/non-bacterial
  • HACEK organisms are now easily cultured so are not common causes of cx-neg endocarditis
  • Most common agents are C. burnetii (Q fever) and Bartonella
  • PCR of blood or removed valves can help identify these organisms

Empiric tx for culture negative endocarditis*

  • Acute native valve: vanc + cefepime (staph/strep, enterococcus, GNRs, fastidious)
    • If subacute (weeks): vanc + ampicillin-sulbactam is sufficient (could also do vanc + CTX)
  • Prosthetic valve <1 year from surgery: vanc + cefepime + gent + rifampin
    • If >1 year out from surgery, vanc + CTX sufficient

*These regimens don’t cover intracellular organisms such as Coxiella or mycoplasma, so would need to add doxycycline depending on history and clinical suspicion. ID consult recommended!!

Mechanical heart valves last 20-30 years. Many human and porcine prosthetic valves fail within 10-15 years.


Complications of prosthetic heart valves:

  • Embolism
  • Bleeding on anticoagulation
  • Valve obstruction/thrombosis/stenosis/regurgitation
  • Endocarditis (valve dehiscence)
  • Hemolytic anemia (usually mild, occasionally severe)

*Paravalvular regurgitation early after surgery is common (18-48%), usually trivial without progression. Frequently detected by intraoperative TEE or post-op TTE.

*The most common later cause of valve dehiscence is infective endocarditis.

From a medicine standpoint for valve dehiscence, our job is to culture, start empiric antibiotics, and diurese aggressively if clinical evidence of heart failure. Management thereafter is surgical.


ECMO indications


  • Cardiac or circulatory failure (cardiogenic shock, cardiac arrest)
  • Bridge to cardiac transplant or ventricular assist device placement
  • Failure to wean from bypass after cardiac surgery


  • Severe refractory hypoxemic or hypercapnic respiratory failure
  • Bridge to lung transplant
  • Massive PE



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