A Multivariable Index for Grading Exercise Gas Exchange Severity in Patients with Pulmonary Arterial Hypertension and Heart Failure

Table 2

Baseline multivariable index (MVI) scoring system.

CUM IVI	MVI = CUM IVI/6	Range	Severity	NYHA
0.00	0.00	<1	Normal	n/a
6.00	1.00	1 and <2	Normal-mild	I
12.00	2.00	2 and <3	Mild-moderate	II
18.00	3.00	3 and <4	Moderate-severe	III
24.00	4.00	≥4	Severe-very severe	IV