Shock and Endocarditis

Today, we discussed a case of likely endocarditis leading to mixed shock. This case illustrated nicely a presenting illness script for endocarditis (though endocarditis can present in a myriad of ways): A patient with little past medical history with subacute constitutional symptoms following a bacteremic stressor (dental procedure) found to have a loud systolic murmur on exam (suggestive of MR), a collection of signs suggestive of cardiogenic shock, and an echocardiogram with regurgitation and an associated abnormality on the mitral valve. Several questions came up from this case:

1. What is the diagnostic utility of PICCO in undifferentiated shock? In general, there is a very good exposition of PICCO use in the blog, Life in the Fast Lane. See here.  The evidence supporting use of PICCO is quite minimal. In general, it is thought to be useful in the setting of mixed shock when volume status and/or diagnosis is in question. In the right patient, you can get a lot of information from its internal calculations, and it just requires a femoral arterial line and a central venous line. I may be stretching appropriate usage of "just" here.

2. When is surgery indicated in infective endocarditis?  There has only been one RCT to look at this question. In the trial, 76 patients with severe left-sided native-valve endocarditis were assigned to surgery within 48 hours or conventional therapy. Those with early surgery did way better (3% vs. 23% rate of combined end-point of death or embolic event), but this was mainly driven by fewer embolic events with surgery. Guidelines suggest the following indications for surgery for left-sided native-valve endocarditis: 1) Signs/Symptoms of new CHF (Class I), 2) Fungal or highly resistant organism (Class I), 3) Heart block, aortic abscess, or penetrating valve lesion (Class I), 4) Persistent bacteremia >7 days post-abx (Class I), 5) Persistent/enlarging vegetation or recurrent emboli despite abx (Class IIa), 6) Severe regurgitation and mobile vegetations >10mm (Class IIa), 7) Mobile vegetations >10mm and other relative indications for surgery (Class IIb).