Myocardial performance index correlates with the BODE index and affects quality of life in COPD patients

Figures & data

Figure 1 Study sample.

Abbreviation: SGRQ, Saint George’s Respiratory Questionnaire.

Table 1 Modified Medical Research Council Dyspnea Scale (mMRC)

Grade	Description of Breathlessness
mMRC 0	I only become breathless with strenuous exercise.
mMRC 1	I become short of breath when hurrying on the level or walking up a slight hill.
mMRC 2	I walk slower than most people the same age on the level because of breathlessness, or I have to stop for breath when walking at my own pace on the level.
mMRC 3	I stop for breath after walking ~100 m or after a few minutes on the level.
mMRC 4	I am too breathless to leave the house or breathless when dressing or undressing.

Figure 2 Measures of the myocardial performance index using tissue Doppler (MPIt) and peak velocity at the annulus (S′).

Notes: Measured using pulsed-wave Doppler of the tricuspid annulus: a, ejection time; b, isovolumic contraction time (1–2) + ejection time (a) + isovolumic relaxation time (3–4). MPI = (b − a)/a.

Table 2 Baseline characteristics of study subjects (n=107)

Variable	Mean ± SD	n	Frequency (%)
Age (years)	65.26±8.81
BMI (kg/m^2)	25.44±5.66
Pack-years smoking history	48.57±38.94
FEV1 (L)	1.37±0.67
FEV1 (%)	52.97±21.33
FVC (L)	3.00±0.97
FVC (%)	91.09±19.22
6mWT (m)	427.48±97.40
pO2 (mmHg)	71.14±16.96
pCO2 (mmHg)	40.89±5.10
Pulse oximetry (%)	93.64±4.92
Current smoker		32	29.9
Former smoker		75	70.1
Male		57	53.3
Exacerbation in the last year		55	51.4
Systemic arterial hypertension		54	50.5
Diabetes		15	14.0
Dyslipidemia		12	11.2
Osteoporosis		9	8.4
Depression		1	0.9

Abbreviations: BMI, body mass index; FEV₁, forced expiratory volume in one second; FVC, forced vital capacity; 6mWT, six-minute walk test; pO₂, partial pressure of oxygen; pCO₂, partial pressure of carbon dioxide.

Figure 3 Distribution of the 107 study subjects according to the BODE index.

Abbreviation: BODE, body mass index, airflow obstruction, dyspnea, and exercise capacity.

Table 3 Results of the Saint George Respiratory Questionnaire (SGRQ) of study subjects that completed it appropriately (n=105)

Domain	Mean ± SD	Median	Minimum	Maximum
Symptom	48.7±21.2	49.4	0.0	88.9
Activity	60.5±21.3	66.2	5.2	93.9
Impact	40.9±21.0	41.5	1.6	95.2
Total score	48.1±18.7	48.5	5.3	86.9

Notes: Results range from 0 to 100; higher scores mean worse quality of life.

Table 4 Anatomic and functional parameters observed in the echocardiograms of study subjects (n=107) and correlation of the right ventricle variables with the BODE index

Heart anatomy and function	Mean ± SD	Correlation with the BODE index
RVOT proximal diameter (mm)	24.5±3.7	r=0.11; P=0.26
RVOT distal diameter (mm)	27.3±3.0	r=0.27; P=0.01
RV basal diameter (mm)	33.2±5.0	r=0.12; P=0.20
RV medium diameter (mm)	23.7±4.8	r=0.02; P=0.84
RV longitudinal diameter (mm)	64.2±8.8	r=0.01; P=1.00
RV wall thickness (mm)	4.9±0.9	r=0.16; P=0.10
RA major dimension (mm)	40.8±6.8	r=−0.06; P=0.52
RA minor dimension (mm)	32.8±6.0	r=0.01; P=0.92
RA area (mm^2)	10.6±3.2	r=0.03; P=0.79
Pulsed-wave tissue Doppler peak velocity at the annulus (cm/s)	11.9±2.0	r=−0.11; P=0.24
TAPSE (mm)	21.6±3.8	r=−0.12; P=0.21
FAC (%)	45.6±7.6	r=−0.07; P=0.46
MPI tissue Doppler	0.4±0.1	r=0.31; P=0.01
MPI pulsed-wave Doppler	0.4±0.2	r=0.22; P=0.02
PA diameter (mm)	19.3±2.6	r=−0.05; P=0.60

Abbreviations: RVOT, right ventricle outflow tract; RV, right ventricle; RA, right atrium; TAPSE, tricuspid annular plane systolic excursion; FAC, fractional area change; MPI, myocardial performance; PA, pulmonary artery; BODE, body mass index, airflow obstruction, dyspnea, and exercise capacity.

Figure 4 Scatter plot of the correlation between the BODE index and tissue Doppler (MPIt).

Abbreviations: MPIt, myocardial performance index using tissue Doppler; BODE, body mass index, airflow obstruction, dyspnea, and exercise capacity.

Figure 5 Mean quality of life scores with 95% CIs between normal myocardial performance index values using tissue Doppler (MPIt; ≤0.55) and MPIt with alterations (>0.55). *P<0.01.

Abbreviation: SGRQ, Saint George’s Respiratory Questionnaire.