3.1 Comparison of the results of clinical baseline characteristics of patients with ACS
When comparing the general information and risk factors of the two groups of patients before exercise, no statistically significant differences were found in the baseline information (all P values > 0.05), except for a statistically significant difference in the mean number of patients with three stents implanted in both groups (P = 0.0308) (Table 1).
Table 1. Comparison of clinical baseline characteristics of patients with ACS
Item
|
Long-term home rehabilitation group
(mean value)
|
Short-term home rehabilitation group
(mean value)
|
Mean difference
|
P value
|
Men/Women
|
0.7777778
|
0.9545455
|
-0.1767677
|
0.0972
|
Age (year)
|
51.66667
|
49.09091
|
2.575758
|
0.4690
|
BMI (kg/m2)
|
23.90278
|
25.59727
|
-1.694495
|
0.1528
|
Number of stents
|
1
|
0.5
|
0.2272727
|
0.2727273
|
0.0752
|
2
|
0.2222222
|
0.2727273
|
-0.0505051
|
0.7221
|
3
|
0
|
0.2272727
|
-0.2272727
|
0.0308
|
4
|
0.0555556
|
0.0909091
|
-0.0353535
|
0.6823
|
STEMI
|
Anterior myocardial infarction
|
0.2777
|
0.2272
|
0.0505
|
0.7221
|
Anteroseptal myocardial infarction
|
0.0556
|
0.0909
|
-0.0353
|
0.6823
|
Inferior myocardial infarction
|
0.2777
|
0.0909
|
0.1868
|
0.1281
|
Lateral myocardial infarction
|
0.0556
|
0.0909
|
-0.0353
|
0.6823
|
Right ventricle myocardial infarction
|
0
|
0.0454
|
-0.0454
|
0.3725
|
NSTEACS
|
0.3888
|
0.5
|
-0.1112
|
0.4949
|
Complications
|
Hypertension
|
0.7777
|
0.5454
|
0.2323
|
0.1319
|
Diabetes
|
0.2222
|
0.2272
|
-0.005
|
0.9706
|
Hyperlipidemia
|
0.5555
|
0.5
|
0.0555
|
0.7345
|
Hyperuricemia
|
0.1111
|
0.1363
|
-0.0252
|
0.8160
|
Smoking (year × number/day)
|
98.33333
|
153.1818
|
-54.84848
|
0.4222
|
3.2 Comparison of CPET
3.2.1 Comparison of CPET parameters before and after rehabilitation in the long-term home rehabilitation group
Table 2 shows the comparison of CPET parameters before and after rehabilitation in the long-term home rehabilitation group. The results of the t test showed that anaerobic threshold (AT VO2), peak oxygen pulse (VO2/HR), peak kilogram oxygen uptake (peak VO2/kg), and peak metabolic equivalents (peak METs) increased in the long-term home rehabilitation group after rehabilitation compared with that before rehabilitation , while the VE/VCO2 slope decreased. The differences in AT VO2, peak VO2/kg, and peak METs were statistically significant (P < 0.05) in terms of the significance shown by the P values.
Table 2. Comparison of CPET parameters before and after rehabilitation in the long-term home rehabilitation group
Item
|
Mean value before rehabilitation
|
Mean value after rehabilitation
|
Mean difference
|
P value
|
ATVO2
|
1015.105
|
1276.522
|
261.4173
|
0.0282
|
Peak VO2/HR
|
10.82778
|
12.78333
|
1.955556
|
0.2736
|
VE/VCO2 slpoe
|
30.34444
|
28.24444
|
-2.1
|
0.4039
|
Peak VO2/kg
|
17.11
|
21.73389
|
4.623889
|
0.0230
|
Peak METs
|
4.833333
|
6.4
|
1.566667
|
0.0044
|
Peak Power
|
100.3889
|
120.4444
|
20.05556
|
0.0706
|
3.2.2 Comparison of CPET parameters before and after rehabilitation in the short-term home rehabilitation group
Table 3 shows the comparison of CPET parameters before and after rehabilitation in the short-term home rehabilitation group. The results of the t test showed that AT VO2, peak METs, and peak power increased in the short-term home rehabilitation group after rehabilitation compared with that before rehabilitation , while the peak VO2/HR, VE/VCO2 slope, peak VO2/kg decreased . In terms of the significance shown by the P value, none of the aforementioned indicators differed statistically significantly (P > 0.05).
Table 3. Comparison of CPET parameters before and after rehabilitation in the short-term home rehabilitation group
Item
|
Mean value before rehabilitation
|
Mean value after rehabilitation
|
Mean difference
|
P value
|
ATVO2
|
1054.372
|
1116.902
|
62.52966
|
0.4544
|
Peak VO2/HR
|
10.98682
|
10.61364
|
-0.3731818
|
0.6973
|
VE/VCO2 slpoe
|
28.61864
|
28.12727
|
-0.4913636
|
0.7225
|
Peak VO2/kg
|
18.06773
|
17.88227
|
-0.1854545
|
0.8747
|
Peak METs
|
5.168182
|
5.231818
|
0.0636364
|
0.8697
|
Peak Power
|
100.5
|
104.9091
|
4.409091
|
0.6043
|
3.2.3 Comparison of the changes in CPET parameters before and after rehabilitation between the long-term and short-term home rehabilitation groups
Table 4 shows the comparison of the changes in CPET parameters before and after rehabilitation between the long-term and short-term home rehabilitation groups. The results of the t test showed that the changes in each CPET in the long-term home rehabilitation group was statistically superior compared with the short-term home rehabilitation group, except for VE/VCO2 slope, which was not statistically significant, and the changes in other indicators in the long-term home rehabilitation group were better than those in the short-term home rehabilitation group and were statistically significant (P < 0.05).
Table 4. Comparison of changes in CPET parameters before and after rehabilitation in the long-term and short-term home rehabilitation groups
Item
|
Long-term home rehabilitation group
(mean value)
|
Short-term home rehabilitation group
(mean value)
|
Mean difference
|
P value
|
△AT VO2
|
261.4173
|
62.52966
|
198.8876
|
0.0160
|
△peak VO2/HR
|
1.955556
|
-0.3731818
|
2.328737
|
0.0036
|
△VE/VCO2 slope
|
-2.1
|
-0.4913636
|
-1.608636
|
0.3438
|
△peak VO2/kg
|
4.623889
|
-0.1854545
|
4.809343
|
0.0042
|
△peak METs
|
1.566667
|
0.0636364
|
1.50303
|
0.0021
|
△peak Power
|
20.05556
|
4.409091
|
15.64646
|
0.0254
|
3.3 Comparison of echocardiographic results
3.3.1 Comparison of echocardiographic parameters before and after rehabilitation in the long-term home rehabilitation group
Table 5 shows the comparison of echocardiographic parameters before and after rehabilitation in the long-term home rehabilitation group. No statistically significant difference was found between the echocardiographic parameters before and after rehabilitation (P > 0.05).
Table 5. Comparison of echocardiographic parameters before and after rehabilitation in the long-term home rehabilitation group
Item
|
Mean value before rehabilitation
|
Mean value after rehabilitation
|
Mean difference
|
P value
|
LVEDd(mm)
|
47.38889
|
48.38889
|
-1
|
0.4866
|
LVESd(mm)
|
30.72222
|
31.88889
|
-1.166667
|
0.4149
|
IVST(mm)
|
9.277778
|
9.222222
|
0.0555556
|
0.8853
|
LVPW(mm)
|
9.166667
|
9
|
0.1666667
|
0.5239
|
LVMI(g/m2)
|
85.00127
|
86.48602
|
-1.484748
|
0.7136
|
LVEF(%)
|
0.5994444
|
0.62
|
-0.0205556
|
0.4012
|
3.3.2 Comparison of echocardiographic parameters before and after rehabilitation in the short-term home rehabilitation group
Table 6 shows the comparison of echocardiographic parameters before and after rehabilitation in the short-term home rehabilitation group. No statistically significant difference was observed between the echocardiographic parameters before and after rehabilitation (P > 0.05).
Table 6. Comparison of echocardiographic parameters before and after rehabilitation in the short-term home rehabilitation group
Item
|
Mean value before rehabilitation
|
Mean value after rehabilitation
|
Mean difference
|
P value
|
LVEDd(mm)
|
48.72727
|
47.40909
|
-1.318182
|
0.4955
|
LVESd(mm)
|
31.59091
|
30.81818
|
-0.7727273
|
0.6757
|
IVST(mm)
|
10.31818
|
10.13636
|
-0.1818182
|
0.7026
|
LVPWT(mm)
|
9.409091
|
9.5
|
0.0909091
|
0.7718
|
LVMI(g/m2)
|
90.75854
|
86.88073
|
-3.877813
|
0.5784
|
LVEF(%)
|
0.6113636
|
0.6186364
|
0.0072727
|
0.7419
|
3.3.3 Comparison of mean values of changes in echocardiographic parameters before and after rehabilitation between the long-term and short-term home rehabilitation groups
Table 7 shows the comparison of mean values of changes in echocardiographic parameters before and after rehabilitation between the long-term and short-term home rehabilitation groups. In terms of the significance of P values, the changes in the left ventricular end-diastolic internal diameter (△LVEDd) and left ventricular end-systolic internal diameter (△LVESd) were statistically significant in the long-term home rehabilitation group compared with the short-term home rehabilitation group, and the difference was statistically significant (P < 0.05). The changes in left ventricular mass index (△LVMI) and The changes in left ventricular ejection fraction(△LVEF) were slightly elevated in the long-term rehabilitation group compared with the short-term rehabilitation group, and the difference was not statistically significant (P > 0.05).
Table 7. Comparison of changes in echocardiographic parameters before and after rehabilitation between the long-term and short-term home rehabilitation groups
Item
|
Long-term home rehabilitation group
(mean value)
|
Short-term home rehabilitation group
(mean value)
|
Mean difference
|
P value
|
△LVEDd(mm)
|
1
|
-1.318182
|
2.318182
|
0.0031
|
△LVESd(mm)
|
1.166667
|
-0.7727273
|
1.939394
|
0.0306
|
△IVST(mm)
|
-0.0555556
|
-0.1818182
|
0.1262626
|
0.7500
|
△LVPWT(mm)
|
-0.1666667
|
0.0909091
|
-0.2575758
|
0.4855
|
△LVMI(g/m2)
|
1.484748
|
-3.877813
|
5.362561
|
0.1764
|
△LVEF(%)
|
0.0205556
|
0.0072727
|
0.0132828
|
0.3998
|
3.3.4 Correlation analysis of LVEF and CPET indexes
The scatter plots shown in Figures 2–7 illustrate that LVEF correlated positively with ATVO2, peak VO2/HR, peak VO2/kg, peak METs, and peak power, and negatively with VE/VCO2 slope.
3.3.5 Multiple regression method analysis of the correlation between LVEF and CPET parameters
As shown in Table 8, LVEF showed a positive and statistically significant correlation with AT VO2 and peak power(r=0.7156828,P=0.009 and r=0.457907,P=0.034); positive but not statistically significant correlation with peakVO2/HR, peak VO2/kg, and peak METs(r=0.3845365,P=0.170、r=0.4081052,P=0.144、r=0.4963648, P=0.079); and negative and statistically significant correlation with VE/VCO2 slope (r=-0.4973823,P=0.003).
Table 8. Analysis of the effect of LVEF on CPET indicators