Evaluating Treatment Options for Patients With Infective Endocarditis

When Is It the Right Time for Surgery?

Aneil Malhotra; Bernard D Prendergast

Disclosures

Future Cardiol. 2012;8(6):847-861. 

In This Article

Systemic Embolism

Systemic embolism occurs in 22–50% of patients with IE and is a life-threatening complication.[57,58] The brain is most frequently affected, accounting for 65% of embolic events from left-sided vegetations, 90% of these arising in the distribution of the middle cerebral artery.[59] However, other organs with large vascular supplies are also often affected, including the lungs, coronary arteries, spleen, liver, bowel and peripheral vasculature. Embolic complications can also be clinically silent in up to one-quarter of cases and detected only after systematic imaging.[59,60]

Although embolic complications may arise at any stage in the natural history of IE, most events occur before diagnosis or subsequently within 2 weeks. Importantly, and specifically in relation to the timing of surgery, several independent studies have confirmed that embolic risk falls dramatically during the first 2 weeks of successful antibiotic therapy (and most steeply within the first three days).[57,61,62] The highest rate of embolic complications is seen in left-sided IE, especially when infection is related to S. aureus, Candida, HACEK and Abiotrophia organisms.

Identifying predictive factors for embolic complications and, in turn, those patients who will benefit most from early surgery is difficult and has been the subject of detailed investigation, at present echocardiography plays a key role.[35,57,61,63–66] Increased vegetation size, mobility[57,59,61,63–68] and location[61,62–65,67] are associated with an increased risk of embolism, as is the dynamic variation of vegetation size under antibiotic therapy.[61,67] Patients with vegetations measuring more than 1 cm in length are at higher embolic risk[57,59,65] and this risk increases even higher with vegetations longer than 1.5 cm.[61] Clinical predictors of embolism include particular microorganisms (staphylococci[61] , Streptococcus bovis[69], Candida), previous embolism,[70] multiple valve IE[71] and biological markers.[72]

The benefits of surgery to prevent embolism are therefore greatest at an early stage, deferral of surgery for 2–3 weeks for this indication alone is of little value. A low threshold for early surgery is most appropriate for patients in whom a conservative procedure (isolated vegetectomy and/or valve repair) is likely or when other factors predict adverse outcome (e.g., severe valvular regurgitation or infection with a resistant microorganism).

Neurological Complications

Neurological events are common in 20–40% of patients with IE, mainly as a consequence of cerebral embolism[58,60,73] and are most common in those with S. aureus infection.[58,60] The clinical spectrum of complications includes ischemic or hemorrhagic stroke, transient ischemic attack, silent cerebral embolism, symptomatic or asymptomatic mycotic aneurysm, cerebral abscess, meningitis, toxic encephalopathy and seizure. All manifestations are associated with excess mortality.[60,70] Figure 2 & Table 3 summarizes the European Society of Cardiology recommendations for the management of neurological complications of IE.[5]

Figure 2.

A schematic flow diagram assessing patients with neurological complications for consideration of valve surgery.
Adapted with permission from [5].

Rapid diagnosis and initiation of appropriate antibiotic therapy are fundamental in the prevention of a first or recurrent neurological event. Most patients with a neurological complication have at least one other indication for cardiac surgery. Although there are concerns regarding the role of surgery in these situations (neurological deterioration or perioperative cerebral bleeding), surgery can be performed without delay provided that cerebral hemorrhage has been excluded by computed tomography and neurological damage is not severe. Pre- and peri-operative risks are low after a silent cerebral embolism, transient ischemic attack or ischemic stroke,[60] although evidence regarding optimal timing is conflicting.[60,74–77] In the presence of cerebral hemorrhage, cardiac surgery should be postponed for at least 1 month[61,63] unless an isolated mycotic aneurysm suitable for endovascular therapy is the source of the cerebral bleed.[78] A bioprosthesis (or valve repair when applicable) is preferred to avoid the need for long-term anticoagulation.

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