The National Infective Endocarditis Database of Denmark (NIDUS) offers one of the most complete and up-to-date datasets on left-sided infective endocarditis, providing a detailed analysis of current surgical practice and revealing a striking reality: surgery remains the cornerstone of treatment, yet mortality continues to be high, and cases are increasingly complex—especially among patients with prosthetic valves or intracardiac devices.

These findings are consistent with the 2023 ESC guidelines (previously reviewed in this blog), which recommend early surgery and systematic evaluation by specialized multidisciplinary “Endocarditis Teams” as key strategies to improve survival. However, the registry highlights that in real-world practice, these recommendations are still not applied uniformly.

The NIDUS registry prospectively included 3,017 patients treated between 2016 and 2021. Of these, 43.7% had a surgical indication, but only half ultimately underwent surgery—equivalent to roughly one-fifth of the entire cohort. The mean age of operated patients was 63 years, with a predominance of males (72%). Notably, more than one-third of surgical cases involved prosthetic valve or device-related endocarditis.

Staphylococcus aureus was the most frequent pathogen, followed by Streptococcus viridans and Enterococcus faecalis. Among patients with surgical indication who were not operated on, S. aureus was particularly prevalent and associated with higher mortality.

The results are compelling: in-hospital mortality was 12.5% among operated patients versus 31% in those with surgical indication who were not operated on. At one year, mortality rose to 17% and 50%, respectively (p < .001). In a time-dependent adjusted analysis, surgery was associated with improved survival (HR 0.87; p = .20 vs patients without surgical indication), whereas failure to operate despite indication doubled the risk of death (HR 1.55; p < .001).

In more than half of the patients with a surgical indication, the reason for not performing surgery was undocumented; when recorded, the most common reason was frailty or prohibitive risk. Furthermore, all operated patients were treated at tertiary centers, whereas only 75% of nonoperated patients with indication were managed in such hospitals—suggesting a major impact of organizational structure on outcomes.

The authors conclude that, although surgery clearly improves survival, it continues to be underperformed relative to guideline recommendations. They advocate for stronger centralization, earlier surgical decision-making, and reinforcement of the Endocarditis Team model as essential elements to optimize outcomes.

COMMENTARY:

The NIDUS registry is not just another study—it is a precise reflection of current real-world practice in infective endocarditis. With more than 3,000 consecutive cases, it offers an honest and detailed view of how and when we operate, and what we still fail to address. Its central message is unequivocal: surgery saves lives, yet it continues to be performed less often than it should.

Patients who underwent surgical intervention demonstrated markedly better survival, even when they presented with higher baseline risk. However, delays in decision-making and failure to transfer patients to tertiary centers remain decisive determinants of mortality. Early surgery, performed within the first few days after diagnosis, is safe and provides clear benefits, particularly in left-sided endocarditis with severe valvular insufficiency, abscesses, or large mobile vegetations.

Another key aspect highlighted by the registry is the steady rise in prosthetic and device-related endocarditis, now accounting for more than one-third of surgical cases. This scenario demands a different mindset and a more radical surgical approach: extensive resection of infected tissue, reconstruction using homografts or autologous pericardial patches, and strict avoidance of potentially contaminated material. Partial or conservative repairs may seem appealing but are associated with higher rates of reinfection and mortality. The surgical principle remains unaltered: eradicate first, then reconstruct.

Although prosthetic valve endocarditis usually carries a surgical indication, not all patients benefit from surgery—and not all are suitable candidates. While I firmly support surgical intervention as a cardiac surgeon, it is equally important to recognize when not to operate—not merely out of technical caution but to avoid futile procedures. Sometimes the best decision is to refrain from opening the chest.

Contemporary evidence suggests that, for a well-defined subgroup, exclusive medical therapy can be reasonable—and sometimes the only viable path to survival. Which profile fits this scenario? Rapid microbiological response (negative blood cultures within ≤72 hours and declining inflammatory markers), transesophageal echocardiography showing no abscess, no prosthetic dehiscence or major dysfunction, small vegetations without ongoing embolic events, infection by susceptible microorganisms, and strict adherence to a prolonged antibiotic regimen under the supervision of an Endocarditis Team. In such cases, nonoperative management is not resignation—it is an informed decision. It avoids prohibitive surgical risk without compromising short- or mid-term outcomes in the absence of surgically correctable lesions, while preserving future options if the clinical situation changes. The key lies in rigorous patient selection, serial documentation of progress (clinical, laboratory, and imaging), and close follow-up—because the success of conservative management depends not on chance, but on precision, teamwork, and the wisdom to identify those who truly fare better without surgery.

In the coming years, this challenge will intensify due to the exponential growth of TAVI procedures. We are likely to face a real epidemic of prosthetic valve endocarditis involving transcatheter prostheses, with significant clinical and surgical implications. Reoperations for TAVI-related endocarditis carry a mortality rate exceeding 15–20% in most series, largely because they frequently require radical root repair or replacement during explantation. Adding infection, patient frailty, and technical complexity to this equation dramatically increases the overall risk. This emerging scenario will demand that surgical teams be fully prepared—both technically and organizationally—to handle an increasing number of these highly complex cases.

The NIDUS data also highlight substantial differences between centers. Institutions with dedicated multidisciplinary teams—comprising surgeons, cardiologists, infectious disease specialists, and imaging experts—achieve better outcomes, lower mortality, and more timely decisions. This level of coordination is not a luxury but a survival tool: when diagnosis, assessment, and surgical indication occur simultaneously, patients live longer.

In Spain, this message carries particular relevance. Every patient with a surgical indication—or with a high likelihood of requiring surgery—should be promptly referred to a tertiary hospital with an active cardiac surgery program and proven experience in endocarditis. Fragmented care and delayed referral remain major causes of avoidable mortality. Centralizing cases and establishing fully functional endocarditis teams in all cardiac surgery centers should be considered a healthcare priority—especially for a disease where timing and coordination are literally vital.

The reality depicted by the Danish registry mirrors what we observe in Spain: frailer patients, more reoperations, and a growing proportion of prosthetic and device-related infections. The figures are comparable, but the message is identical: we must identify earlier, refer earlier, and operate earlier. Skill alone is not enough—structure, standardized protocols, and cohesive teams are equally critical.

Despite its complexity, infective endocarditis remains a disease where surgery makes a decisive difference. The NIDUS registry should not be read as a mere snapshot of current practice, but as a call to action: to centralize care in specialized centers, make timely surgical decisions, and consolidate endocarditis teams as a mandatory model of care.

REFERENCE:

Graversen PL, Østergaard L, Hadji-Turdeghal K, Møller JE, Bruun NE, Povlsen JA, et al. Clinical practice of surgical treatment for left-sided infective endocarditis: nationwide data from the NIDUS registry. Circulation. 2025 Aug 21. doi:10.1161/CIRCULATIONAHA.125.074608.