Surgery for native aortic valve infective endocarditis

Introduction

Heart valve infections are a quite uncommon pathology with an estimated annual incidence of 3–10 cases in 100,000 in a normal population. With a mortality standing between 15% and 30% (according to clinical circumstances and to the infective organism) [ , ], this pathology still remains a life-threatening disease that causes also significant morbidity.

As a result of the enormous progress made in terms of diagnosis and treatment, the epidemiological profile of infective endocarditis (IE) has changed in recent decades, as shown by the EURO-ENDO registry. According to the paper published by EURO-ENDO Investigators in 2019 [ ], nowadays IE more frequently affects older patients (predominantly male over 60 year of age) with comorbidities. Prosthetic valve IE, intracardiac device-related IE, nosocomial, staphylococcal, and enterococcal endocarditis are also more frequent.

Moreover, oral streptococcal endocarditis is less frequent, and its frequency has not increased since implementation of the 2009 and 2015 recommendations restricting indications for antibiotic prophylaxis. These considerations help to draw the contemporary profile of patients suffering from IE.

Endocarditis team

As described in 2015 Guidelines, the presence of an Endocarditis Team is strongly recommended in order to manage the complexity of this pathology [ ]. The Team is composed of cardiac surgeons, cardiologists, anesthesiologists, infectious disease specialists, microbiologists and, when available, specialists in valve diseases, congenital heart disease, pacemaker extraction, echocardiography and other cardiac imaging techniques, neurologists, and facilities for neurosurgery and interventional neuroradiology. Besides the intrahospital management of the patients, the Endocarditis Team should organize a correct assessment and follow-up in line with the very latest recommendations and participate in patient education program. As shown in the 2019 paper of Davierwala and colleagues, the Endocarditis Team approach facilitates early diagnosis, implementation of comprehensive therapeutic strategies and appropriate decision-making, which could potentially play an important role in reducing the high morbidity and mortality associated with this disease [ ].

Timing of surgery

It's experts' opinion that surgical treatment is necessary in approximately half of the patients suffering from IE, in order to prevent severe complications such as heart failure, uncontrolled infection, and embolism [ ]. In this context, all US and European guidelines are aligned on the indication of early surgery when surgery is needed [ , , ].

Early surgery means a surgery “during initial hospitalization before completion of a full therapeutic course of antibiotics” [ ]. Early surgery should be performed in IE with valve disfunction in order to prevent heart failure, in case of infection by multiresistant microorganisms ( Staphylococcus aureus , fungal, or others), in presence of abscess, heart block, or deep tissues destruction, and in case of a persistent bacteremia and/or fever longer than 5–7 days after onset of an appropriate antibiotic therapy. Other indications of early surgery are a vegetation larger than 1 cm, and recurrent emboli. In selected patients with large ad unstable vegetation, an emergency (within 48 h) surgery should be considered. In case of cardiogenic shock, an emergency surgery (within 24 h) could be performed [ ].

While in the abovementioned cases the recommendations are quite intuitive, there are some difficult scenarios that the Team has to deal with. In fact, symptomatic neurological events develop in 15%–30% of all patients with IE, and additional silent events are frequent. How to handle these situations? Evidence regarding the ideal time interval between stroke and cardiac surgery is inconsistent, but most recent data favor early surgery. If any significant cerebral hemorrhage has been excluded by radiological and clinical assessment and if neurological clinical state is not severely compromised, surgery should not be delayed and can be performed with a low neurological risk (3%–6%) and good probability of complete neurological recovery [ , ]. Contrariwise, patients with intracranial hemorrhage have worse neurological prognosis and surgery should generally be postponed for 2–4 weeks [ , ].