Endocarditis and narrow root: when the Nicks technique prevents mismatch

The challenge of infective endocarditis on a narrow aortic root

Surgical management of infective endocarditis is complicated when the patient's anatomy presents a narrow aortic root, increasing the risk of patient-prosthesis mismatch (PPM). This clinical case details the operative strategy adopted for a 65-year-old man with an Enterococcus faecalis infection, characterized by massive vegetations, severe aortic and tricuspid regurgitation, as well as critical coronary stenoses.

The primary objective of this report is to demonstrate the efficacy of the Nicks procedure (aortic root enlargement) to allow the implantation of an adequately sized prosthesis despite a restricted native annulus. Based on the preoperative calculation of the indexed effective orifice area (iEOA), the authors illustrate how the integration of enlargement techniques (Nicks, Manouguian, or Yang) into a major cardiac surgery protocol — including here a triple bypass and multiple valve replacement — prevents PPM and optimizes long-term hemodynamic outcomes in adults.

Design and surgical protocol

This case report details the surgical strategy implemented for a 65-year-old patient presenting with Enterococcus faecalis infective endocarditis (vancomycin-susceptible) complicated by a narrow aortic root. The primary objective was to restore valvular and coronary function while avoiding patient-prosthesis mismatch (PPM).

The diagnostic and surgical protocol followed these steps:

• Preoperative evaluation: Use of transesophageal echocardiography (TEE) and coronary computed tomography angiography (CCTA) to identify vegetations, quantify regurgitation and measure coronary stenoses (left main coronary artery and right coronary artery).
• Hemodynamic calculation: Determination of the indexed effective orifice area (iEOA) to anticipate the risk of moderate PPM related to the narrowness of the aortic root.
• Complex surgical procedure: Emergency performance of a combined procedure including:
  • An aortic and tricuspid valve replacement.
  • A mitral valve repair.
  • A triple coronary artery bypass graft (CABG).
• Widening technique: Implementation of the Nicks procedure to increase the circumference of the aortic annulus, allowing the implantation of an appropriately sized prosthesis despite the patient's initial anatomy.

The analysis is based on the correlation between preoperative imaging data and the technical feasibility of annular enlargement to optimize postoperative hemodynamic results.

Clinical presentation and microbiological profile

A 65-year-old patient was admitted with a clinical presentation of infective endocarditis (IE) combining fever, progressive dyspnoea, lower limb oedema, and de novo angina. Blood cultures identified Enterococcus faecalis, sensitive to vancomycin.

Lesional assessment and anatomical constraints

Transesophageal echocardiography (TEE) and coronary CT angiography have highlighted a severe pathological complex:

• Severe aortic and tricuspid regurgitation with large vegetations.
• Moderate mitral regurgitation.
• Narrow aortic root.
• Critical stenoses of the left main stem and the right coronary artery.

Surgical strategy and Nicks procedure

The urgent intervention required a combined approach to treat valvular and coronary lesions while anticipating the risk of patient-prosthesis mismatch (PPM). The following table summarizes the interventions performed:

The Nicks procedure was specifically chosen to enlarge the narrow aortic root. This technique allowed for the implantation of a prosthesis of sufficient size to ensure an adequate indexed effective orifice area (iEOA), thus avoiding moderate PPM that would have compromised the long-term hemodynamic prognosis.

Clinical analysis: the trade-off between urgency and hemodynamics

This clinical case highlights the management of a particularly severe Enterococcus faecalis infective endocarditis (IE). The patient presented with triple valve involvement (aortic, tricuspid, mitral) associated with critical coronary artery disease (left main stem and right coronary artery). The major difficulty lay in the narrowness of the aortic root, increasing the risk of patient-prosthesis mismatch (PPM) if a standard-sized valve had been implanted without adjustment.

The use of the Nicks procedure to enlarge the aortic root allowed for the implantation of a prosthesis providing an adequate indexed effective orifice area (iEOA). In this context of major surgery (triple bypass + triple valvular procedure), the root enlargement demonstrates that it is possible to optimize left ventricular hemodynamics without compromising immediate survival, despite the added technical complexity.

The limitations of this study lie in its nature: a single case report (n=1). Although it perfectly illustrates the application of the 2023 ESC recommendations cited by the authors, it does not allow for a statistical comparison of the effectiveness of the Nicks technique compared to alternatives such as the Manouguian or Yang procedures. However, it confirms that root enlargement remains a viable and necessary option, even in the acute infectious phase with large vegetations.

The crucial point raised by the authors is the importance of systematic preoperative iEOA calculation. This step is decisive for anticipating PPM, particularly in adult patients whose aortic root morphology is limiting for standard biological or mechanical prostheses.

Study summary

This case report details the management of Enterococcus faecalis endocarditis in a 65-year-old patient requiring complex intervention (AVR, TVR, mitral repair, and triple bypass). The execution of a Nicks procedure allowed for the enlargement of the narrow aortic root, ensuring a sufficient indexed effective orifice area (iEOA) to prevent moderate patient-prosthesis mismatch (PPM).

In concrete terms, for the practitioner:

• Calculate the iEOA preoperatively: This is the essential step to anticipate the risk of mismatch, particularly in patients with a narrow aortic root anatomy.
• Mastering enlargement techniques: Nicks, Manouguian, or Y-incision (Yang) procedures must be part of the therapeutic arsenal to allow the implantation of an optimally sized prosthesis.
• Prioritize hemodynamics: Even in emergency contexts or heavy combined surgeries, root enlargement remains a viable strategy to ensure the functional durability of the valve replacement.

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