The "Risk-E score for perioperative mortality in infective endocarditis" provides a way to evaluate a patient's risk of mortality during surgery by analyzing several critical clinical factors. Here's how the calculator works, from input through to interpretation:

The calculator requires the user to answer questions about eight specific clinical factors:

- Age, which is categorized into four groups: <= 51 years, 52-63 years, 64-72 years, and >= 73 years.
- Whether the patient has prosthetic endocarditis.
- If a virulent microorganism such as Staphylococcus aureus or fungi is present.
- The presence of septic shock.
- Whether the patient has thrombocytopenia, defined as having fewer than 150,000 platelets per mm³.
- The presence of acute renal insufficiency.
- Whether the patient is experiencing cardiogenic shock.
- Any periannular complications, including an abscess, pseudoaneurysm, fistula, or prosthetic dehiscence.

Each response the user provides is assigned a score based on predetermined criteria:

- Age: Scores are progressively higher with increased age, ranging from 0 to 14.
- Prosthetic endocarditis: Adds 6 points if present.
- Virulent microorganisms: Add 9 points if Staphylococcus aureus or fungi are involved.
- Septic shock: Contributes 7 points if present.
- Thrombocytopenia: Adds 7 points if platelet count is low.
- Acute renal insufficiency: Adds 5 points if present.
- Cardiogenic shock: Adds the highest single score, 15 points, if present.
- Periannular complications: Contributes 5 points if any complications are detected.

By summing these scores, the calculator produces a total risk score. This score is then compared to a predefined scale which correlates each score with a percentage risk of perioperative mortality. For example, a score of 0 equates to a 3.36% risk, while a score of 68 indicates a 97.01% risk.

The interpretation of this score provides a percentage that assists healthcare professionals in assessing the perioperative mortality risk associated with infective endocarditis cases. It allows them to communicate potential risks effectively based on specific patient presentations. The score guides clinical decision-making by offering a nuanced understanding of the risk which can influence the management and therapeutic approaches for the patient.

The Risk-E score, or Risk Endocarditis score, is a clinical calculator used to predict perioperative mortality in patients with infective endocarditis. This scoring system is specifically designed for patients undergoing surgery for infective endocarditis, a serious infection of the heart's inner lining, usually involving the heart valves. 

The Risk-E score is clinically useful in helping clinicians to stratify the risk of death in the perioperative period, which can guide decision-making regarding the timing and necessity of surgery. It takes into account various factors such as patient age, presence of comorbidities, causative organism, and echocardiographic findings.

There are no specific exclusion criteria for the use of the Risk-E score, but it should be noted that it is most applicable to patients with infective endocarditis who are being considered for surgical intervention. It may not be as relevant or accurate in patients with infective endocarditis who are being managed medically, or in patients with other types of endocarditis (e.g., non-infective endocarditis).