Papillary muscle rupture is classified into three categories: ischemic, non-ischemic, and iatrogenic. The non-ischemic subset involves patients with blunt chest trauma, myxomatous disease, spontaneous rupture, and rarely, infective endocarditis as in our patient. Papillary muscle rupture results in severe mitral regurgitation, regardless of the etiology. Unlike with ischemic causes of papillary rupture, patients with non-ischemic etiology have preserved ventricular function, and thus less burden of cardiogenic shock. Although the operative management of papillary muscle rupture may be similar, the etiology of disease differentiates the timing of surgical intervention and outcome.
The timing of sterilization with antibiotics and surgical intervention depends on symptomatic severity and stability (3). In patients with acute left-sided valvular regurgitation due to infective endocarditis resulting in heart failure, early surgical intervention prior to antibiotic sterilization is the current guideline recommendation (4, 5). In patients who receive early surgical intervention, risk of mortality is significantly lower compared to late surgical intervention (6).
Although reimplantation of the ruptured papillary muscle might be technically feasible, it is not viable in this patient population, as most are in cardiogenic shock at the time of operation. Furthermore, the rate of recurrent papillary muscle rupture is higher, especially with necrotic tissue. Importantly, in patients with papillary muscle rupture due to infective etiology, extensive debridement and removal of infective tissue is key to eradicating infection, and thus reimplantation is not a viable intervention.
Thus, these patients are better served with valve replacement. Bioprosthetic and mechanical valves have similar long-term outcomes and risk for endocarditis recurrence (7). Thus, choice of valve, bioprosthetic or mechanical, is up to patient preference. Many patients prefer bioprostheic valves to avoid lifelong anticoagulation, as in our case.
Choice of antibiotic and duration of treatment is another critical factor in the management of patients with infective endocarditis. Blood or tissue cultures are essential in identifying the microorganism involved and directing therapy. In patients with coagulase-negative Staphylococcus infection, as in our patient, treatment with prosthetic valve replacement and a six-week course of vancomycin therapy is recommended (8). Repeat blood cultures every 24 to 48 hours are necessary to monitor response to antibiotic therapy.