The calculator in question is the Assessment of Diastolic Dysfunction Severity (with Left Ventricular Structural Pathology). This clinical calculator is used primarily in the field of cardiology, specifically for patients who have been diagnosed with diastolic heart failure or are suspected of having this condition. 

The clinical utility of this calculator is to assess the severity of diastolic dysfunction in patients with structural pathology of the left ventricle. It helps in stratifying the risk and guiding the management of patients with diastolic heart failure. The calculator uses parameters such as left atrial volume index, tricuspid regurgitation velocity, and average E/e' ratio to determine the severity of diastolic dysfunction.

Exclusion criteria for its use would include patients without structural pathology of the left ventricle, those with systolic heart failure, and patients with other types of heart diseases that could affect the parameters used in the calculator. It's also important to note that this calculator should be used in conjunction with other clinical assessments and not as a standalone diagnostic tool.

Assessment of diastolic dysfunction severity (with LV structural pathology)

# Criteria
 A. Average E/e' ratio > 14 (+1)
B. Peak TR velocity > 2.8 m/s (+1)
C. Left atrial volume index > 34 mL/m**2 (+1)

# Conditions
- score >= 2
- true
- score == 0

Recommendations for the Evaluation of Left Ventricular Diastolic Function by Echocardiography: An Update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging.