Ann Thorac Surg 2007;83:2086
© 2007 The Society of Thoracic Surgeons
Original Articles: Cardiovascular
Invited commentary
Tomas Salerno, MD,
Marco Ricci, MD
Division of Cardiothoracic Surgery, Jackson Memorial Hospital, University of Miami, 1611 NW 12th Ave, East Tower 3072 (R-114), Miami, FL 33136
(Email: tsalerno{at}med.miami.edu).
Patients with chronic renal failure require vascular access for dialysis. This can be in the form of an indwelling catheter in the subclavian vein, internal jugular, or another central vein, or through an arteriovenous fistula or shunt. These patients are often immunocompromised due to uremia. As a result, they are at risk for bacteremia, infections, and endocarditis of one or multiple heart valves. The current study by Kamalakannan and colleagues [1] demonstrates that left-sided valves are most vulnerable to infection, as the observed incidence of mitral, aortic, and tricuspid valve endocarditis was 49.3%, 21.7%, and 10.1%, respectively. The authors also noted that Staphylococcus aureus was the predominant organism. The observed mortality for the group of patients that was treated medically was very high (almost 50%), whereas the patients who were treated surgically was significantly lower (ie, survival of 12 of 15 patients with surgery and 23 of 54 without surgery; p < 0.018).
Definitive conclusions regarding the role that surgical intervention may have in reducing mortality in these complex patients may be difficult to draw from this study, as patients treated medically might have been sicker. However, several other aspects of this study merit discussion. One important consideration relates to the prevention of such infections in patients with renal failure and indwelling lines. Although not adequately addressed in this article, it is worth mentioning that several are the measures that can minimize the potential for infection. Strict hygiene, cleaning of the site, periodical catheter changes, utilization of different sites, and sterile techniques when accessing arterio-venous fistulas or shunts may all play a role in reducing the incidence of these infections.
Once endocarditis has occurred and medical treatment has failed, surgery often provides the only hope for survival, as shown by the authors. What is not reported by the article is the type of prostheses used for valve replacement (ie, mechanical versus biological valves). This has great importance because it may have implications with the anticoagulation management of these patients as well as with the risk of prosthetic valve reinfection. Also, the authors do not report the incidence of reinfection of the prosthesis that was observed in their cohort. This information is of critical value to draw conclusions as to what the best management of these complex patients may entail if valve replacement is necessary.
In this study, septic emboli occurred in 50% of the patients, whereas 37.7% of the patients had an adverse neurologic event. This may suggest that early, rather than late intervention should be strongly considered in patients with evidence of endocarditis of a left-sided valve with vegetation. This point was also not adequately addressed in this article and has important clinical implications in terms of long-term outcome.
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References
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- Kamalakannan D, Pai RM, Johnson LB, Gardin JM, Saravolatz LD. Epidemiology and clinical outcomes of infective endocarditis in hemodialysis patients Ann Thorac Surg 2007;83:2081-2086.[Abstract/Free Full Text]
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