359 Invasive Validation of ‘The Oh Factor’ – a Simple, One-step Algorithm for Determining Left Ventricular Filling Pressure in All Patients.

Abstract

Numerous algorithms have been proposed to determine left ventricular filling pressure (LVFP) using echocardiographic parameters. The 2016 guideline algorithm suggests different pathways for patients with and without myocardial disease. Recently, Dr Jae Oh, Mayo Clinic, has proposed a simplified algorithm, ‘The Oh Factor’, for assessment of LVFP in all patients. Patients enrolled in the CATHARSIS study undertook comprehensive echocardiography and contemporaneous left heart catheterization (pre-A pressure) whilst nil by mouth. Filling pressure and diastolic grade determined by the Oh factor was compared to invasive LVFP. Invasive LVFP was obtained in 155 patients (age 64.6±12.1, female 30%, ejection fraction 54.7±11.8%, pre-A pressure 10±4mmHg). Using a cut-off of ≤12mmHg for normal pre-A pressure, the Oh factor accurately identified normal LVFP in 90/103 (87%) of patients and elevated LVFP in 8/14 (57%) of patients, with indeterminate classification in 38/155 patients (25%). Increasing mean invasive LVFP was observed with increasing Oh factor derived diastolic grade (normal 10.2±3.6mmHg, grade 1 9.0±4.4mmHg, indeterminate 10.0±3.7mmHg, grade 2 14.0±4.6, grade 3 15±3.8mmHg), with significant differences between patients with normal and grade 1 diastolic function and patients with grade 2 and grade 3 dysfunction (p=0.003 and 0.009 respectively). The simplified Oh factor algorithm is highly accurate in identifying patients with normal filling pressures and correlates mean invasive pressure and diastolic grade. Further refinement is required to improve accuracy in identification of patients with elevated filling pressures.