Cardiol Res

Cardiology Research, ISSN 1923-2829 print, 1923-2837 online, Open Access

Article copyright, the authors; Journal compilation copyright, Cardiol Res and Elmer Press Inc

Journal website https://www.cardiologyres.org

Original Article

Volume 15, Number 1, February 2024, pages 56-66

Improving Respiratory Muscle Strength and Overall Function in Patients With Cardiovascular Disease Through Rehabilitation Hospitals

Figure 2. Changes in respiratory muscle strength. (a, b) Actual maximal inspiratory and expiratory pressure. (c, d) Calculated % maximal inspiratory and expiratory pressure. In the box-and-whisker plot, the box represented the interquartile range (IQR), while the whiskers extended to the minimum and maximum values within 1.5 times the IQR. Data points outside this range were considered outliers and were represented by circles.

**Table 1.** Baseline Characteristics of the Patients
	N = 30
AVG: average; SD: standard deviation; E/e’: early diastolic transmitral flow velocity to early diastolic mitral annular tissue velocity ratio; NYHA class: New York Heart Association functional classification; eGFR: estimated glomerular filtration rate; GNRI: geriatric nutritional risk index; ACEi: angiotensin-converting enzyme inhibitor; ARB: angiotensin II receptor blocker; CR: cardiac rehabilitation.
Basic data
Age (years)	76.4	10.3
Male, n (%)	9 (30.0)
Body mass index (kg/m²)	20.0	4.1
Barthel index before hospitalization	97.0	6.4
Kihon checklist before hospitalization	7.5	5.3
Robust, n (%)	8 (26.7)
Pre-frailty, n (%)	10 (33.3)
Frailty, n (%)	12 (40.0)
Living alone, n (%)	18 (60.0)
Length of hospital stay before transfer, days	31.2	16.4
Principal disease before transfer, n (%)
Heart failure	4 (13.3)
Cardiac surgery	14 (46.7)
Contents of cardiac surgery, n (%)
Coronary artery bypass grafting	3 (21.4)
Valve surgery	2 (14.3)
Multiple valve surgery	5 (35.7)
Coronary artery bypass grafting + valve surgery	2 (14.3)
Others	2 (14.3)
Aortic surgery	10 (33.3)
Combined surgery (cardiac and aortic surgery)	2 (6.7)
Information after transfer
Prevalence of possible respiratory sarcopenia	28 (93.3)
NYHA class, n (%)
Class 1	0 (0)
Class 2	3 (10.0)
Class 3	26 (86.7)
Class 4	1 (3.3)
Charlson comorbidity index	2.7	1.5
Comorbidities, n (%)
Diabetes mellitus	8 (26.7)
Chronic heart failure	12 (40.0)
Chronic kidney disease	6 (20.0)
Chronic obstructive pulmonary disease	2 (6.7)
Musculoskeletal disorders	15 (50.0)
Cerebrovascular disease	7 (23.3)
Peripheral arterial disease	1 (3.3)
Echocardiography
Left ventricular ejection fraction, %	55.5	11.3
Left atrial dimension, mm	36.3	7.6
E/e’	15.0	5.7
Laboratory data
Hemoglobin, g/dL	11.3	1.4
Albumin, g/dL	3.3	0.4
Creatinine, mg/dL	0.95	0.45
eGFR, mL/min/1.73 m²	59.5	26.7
C-reactive protein, mg/dL	1.94	2.53
Brain natriuretic peptide, pg/mL	176.3	108.9
GNRI	86.5	11.2
Medication, n (%)
Beta-blocker	21 (70.0)
ACEIi/ARB	8 (26.7)
Diuretics	17 (56.7)
Others
Total CR time, min/day	132.5	13.4
Percentage with combined breathing training, n (%)	19 (63.3)
Length of hospital stay, days	65.9	30.4
Home discharge, n (%)	28 (93.3)

Table 1. Baseline Characteristics of the Patients

N = 30

AVG

AVG: average; SD: standard deviation; E/e’: early diastolic transmitral flow velocity to early diastolic mitral annular tissue velocity ratio; NYHA class: New York Heart Association functional classification; eGFR: estimated glomerular filtration rate; GNRI: geriatric nutritional risk index; ACEi: angiotensin-converting enzyme inhibitor; ARB: angiotensin II receptor blocker; CR: cardiac rehabilitation.

Basic data

Age (years)

76.4

10.3

Male, n (%)

9 (30.0)

Body mass index (kg/m²)

20.0

4.1

Barthel index before hospitalization

97.0

6.4

Kihon checklist before hospitalization

7.5

5.3

Robust, n (%)

8 (26.7)

Pre-frailty, n (%)

10 (33.3)

Frailty, n (%)

12 (40.0)

Living alone, n (%)

18 (60.0)

Length of hospital stay before transfer, days

31.2

16.4

Principal disease before transfer, n (%)

Heart failure

4 (13.3)

Cardiac surgery

14 (46.7)

Contents of cardiac surgery, n (%)

Coronary artery bypass grafting

3 (21.4)

Valve surgery

2 (14.3)

Multiple valve surgery

5 (35.7)

Coronary artery bypass grafting + valve surgery

2 (14.3)

Others

2 (14.3)

Aortic surgery

10 (33.3)

Combined surgery (cardiac and aortic surgery)

2 (6.7)

Information after transfer

Prevalence of possible respiratory sarcopenia

28 (93.3)

NYHA class, n (%)

Class 1

0 (0)

Class 2

3 (10.0)

Class 3

26 (86.7)

Class 4

1 (3.3)

Charlson comorbidity index

2.7

1.5

Comorbidities, n (%)

Diabetes mellitus

8 (26.7)

Chronic heart failure

12 (40.0)

Chronic kidney disease

6 (20.0)

Chronic obstructive pulmonary disease

2 (6.7)

Musculoskeletal disorders

15 (50.0)

Cerebrovascular disease

7 (23.3)

Peripheral arterial disease

1 (3.3)

Echocardiography

Left ventricular ejection fraction, %

55.5

11.3

Left atrial dimension, mm

36.3

7.6

E/e’

15.0

5.7

Laboratory data

Hemoglobin, g/dL

11.3

1.4

Albumin, g/dL

3.3

0.4

Creatinine, mg/dL

0.95

0.45

eGFR, mL/min/1.73 m²

59.5

26.7

C-reactive protein, mg/dL

1.94

2.53

Brain natriuretic peptide, pg/mL

176.3

108.9

GNRI

86.5

11.2

Medication, n (%)

Beta-blocker

21 (70.0)

ACEIi/ARB

8 (26.7)

Diuretics

17 (56.7)

Others

Total CR time, min/day

132.5

13.4

Percentage with combined breathing training, n (%)

19 (63.3)

Length of hospital stay, days

65.9

30.4

Home discharge, n (%)

28 (93.3)

**Table 2.** Change in Rehabilitation Outcome in the Patient on and off Beta-Blockers
Amount of change	On beta-blocker (n = 21)	Off beta-blocker (n = 9)	P value
AVG: average; SD: standard deviation; %MIP: % maximal inspiratory pressure; %MEP: % maximal expiratory pressure; FIM: functional independence measure; SPPB: short physical performance battery; 6MD: 6-min walking distance.
%MIP, %	53.3	40.3	35.7	53.5	0.328
%MEP, %	26.5	33.4	49.1	76.5	0.264
FIM, points	43.2	13.4	45.3	12.0	0.690
SPPB, points	3.3	2.2	3.4	2.8	0.929
Gait speed, m/s	0.39	0.28	0.41	0.31	0.884
Hand grip strength, kg	1.3	2.6	1.2	2.1	0.971
Knee extension strength, %BW	10.1	6.0	9.9	11.7	0.962
6MD, m	97.2	59.9	179.8	114.7	0.087

Table 2. Change in Rehabilitation Outcome in the Patient on and off Beta-Blockers

Amount of change

On beta-blocker (n = 21)

Off beta-blocker (n = 9)

P value

AVG

AVG: average; SD: standard deviation; %MIP: % maximal inspiratory pressure; %MEP: % maximal expiratory pressure; FIM: functional independence measure; SPPB: short physical performance battery; 6MD: 6-min walking distance.

%MIP, %

53.3

40.3

35.7

53.5

0.328

%MEP, %

26.5

33.4

49.1

76.5

0.264

FIM, points

43.2

13.4

45.3

12.0

0.690

SPPB, points

3.3

2.2

3.4

2.8

0.929

Gait speed, m/s

0.39

0.28

0.41

0.31

0.884

Hand grip strength, kg

1.3

2.6

1.2

2.1

0.971

Knee extension strength, %BW

10.1

6.0

9.9

11.7

0.962

6MD, m

97.2

59.9

179.8

114.7

0.087

**Table 3.** Changes in ADL, Physical Function, Exercise Tolerance, Cognitive Function, and QoL After Rehabilitation
	Before rehabilitation	After rehabilitation	P value
AVG: average; SD: standard deviation; FIM: functional independence measure; SPPB: short physical performance battery; 6MD: 6-min walking distance; MMSE: mini-mental state examination; EQ-5D-5L: EuroQol five-dimension five-level.
FIM, points	72.0	16.8	116.0	10.1	< 0.001
FIM-motor, points	46.3	11.9	82.7	8.1	< 0.001
FIM-cognitive, points	25.7	7.6	33.2	3.5	< 0.001
SPPB, points	7.5	3.1	10.7	2.0	< 0.001
Gait speed, m/s	0.76	0.32	1.14	0.39	< 0.001
Hand grip strength, kg	16.2	6.2	17.3	6.1	0.010
Knee extension strength, %BW	30.6	15.1	40.6	17.8	< 0.001
6MD, m	222.9	124.9	341.5	128.7	< 0.001
MMSE, points	26.6	2.8	27.4	2.9	0.038
EQ-5D-5L	0.588	0.168	0.790	0.183	< 0.001
Mobility	-0.078	0.074	-0.025	0.044
Self-care	-0.042	0.042	-0.019	0.028
Usual activities	-0.094	0.058	-0.038	0.047
Pain/discomfort	-0.046	0.034	-0.026	0.028
Anxiety/depression	-0.053	0.051	-0.035	0.053

Table 3. Changes in ADL, Physical Function, Exercise Tolerance, Cognitive Function, and QoL After Rehabilitation

Before rehabilitation

After rehabilitation

P value

AVG

AVG: average; SD: standard deviation; FIM: functional independence measure; SPPB: short physical performance battery; 6MD: 6-min walking distance; MMSE: mini-mental state examination; EQ-5D-5L: EuroQol five-dimension five-level.

FIM, points

72.0

16.8

116.0

10.1

< 0.001

FIM-motor, points

46.3

11.9

82.7

8.1

< 0.001

FIM-cognitive, points

25.7

7.6

33.2

3.5

< 0.001

SPPB, points

7.5

3.1

10.7

2.0

< 0.001

Gait speed, m/s

0.76

0.32

1.14

0.39

< 0.001

Hand grip strength, kg

16.2

6.2

17.3

6.1

0.010

Knee extension strength, %BW

30.6

15.1

40.6

17.8

< 0.001

6MD, m

222.9

124.9

341.5

128.7

< 0.001

MMSE, points

26.6

2.8

27.4

2.9

0.038

EQ-5D-5L

0.588

0.168

0.790

0.183

< 0.001

Mobility

-0.078

0.074

-0.025

0.044

Self-care

-0.042

0.042

-0.019

0.028

Usual activities

-0.094

0.058

-0.038

0.047

Pain/discomfort

-0.046

0.034

-0.026

0.028

Anxiety/depression

-0.053

0.051

-0.035

0.053