The calculator in question is the Assessment of Diastolic Function (no LV structural pathology). This calculator is used in the specific patient population of individuals suspected of having diastolic dysfunction but who do not have any structural pathology of the left ventricle (LV). 

The clinical utility of this calculator is to assess the diastolic function of the heart, which is the phase of the cardiac cycle when the heart relaxes and fills with blood. This is crucial in diagnosing conditions such as heart failure with preserved ejection fraction (HFpEF), also known as diastolic heart failure. 

The calculator uses parameters such as mitral inflow velocities, tissue Doppler imaging, and left atrial size to determine the likelihood of diastolic dysfunction. 

Exclusion criteria for its use would include patients with significant left ventricular structural abnormalities, such as hypertrophy or dilation, as these could affect the diastolic function independently. Additionally, it may not be suitable for patients with certain arrhythmias or severe valvular diseases, as these conditions can also influence the parameters used in the calculator.

Assessment of diastolic function (no LV structural pathology)

# Criteria
 A. Septal e' < 7 cm/s or lateral e' < 10 cm/s (+1)
B. Average E/e' ratio > 14 (+1)
C. Peak TR velocity > 2.8 m/s (+1)
D. Left atrial volume index > 34 mL/m**2 (+1)

# Conditions
- score >= 3
- 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.