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://cr.elmerpub.com

Original Article

Volume 17, Number 5, October 2026, pages 526-533

Prolonged Mechanical Ventilation and In-Hospital Mortality Following Open-Heart Surgery: A Retrospective Cohort Study

↓ **Table 1.** ROC Curve Analysis of Continuous Variable Toward In-Hospital Mortality and PMV
Outcome	Predictor	AUC (95% CI)	P-value	Optimal cut-off	Sensitivity (%)	Specificity (%)
*Statistically significant results (P < 0.05). AUC: area under the curve; CI: confidence interval; PMV: prolonged mechanical ventilation.
Mortality	Age	0.622 (0.533 to 0.712)	0.009*	61.5 (∼62)	51.1	69.8
	Duration of surgery	0.633 (0.541 to 0.726)	0.004*	280.50 (∼280)	38.3	86.1
PMV > 24-h	Age	0.528 (0.455 to 0.601)	0.461	-	-	-
	Duration of surgery	0.512 (0.437 to 0.587)	0.751	-	-	-
PMV ≥ 96-h	Age	0.554 (0.387 to 0.721)	0.498	-	-	-
	Duration of surgery	0.588 (0.424 to 0.752)	0.268	-	-	-

↓ Table 1. ROC Curve Analysis of Continuous Variable Toward In-Hospital Mortality and PMV

Outcome

Predictor

AUC (95% CI)

P-value

Optimal cut-off

Sensitivity (%)

Specificity (%)

*Statistically significant results (P < 0.05). AUC: area under the curve; CI: confidence interval; PMV: prolonged mechanical ventilation.

Mortality

Age

0.622 (0.533 to 0.712)

0.009*

61.5 (∼62)

51.1

69.8

Duration of surgery

0.633 (0.541 to 0.726)

0.004*

280.50 (∼280)

38.3

86.1

PMV > 24-h

Age

0.528 (0.455 to 0.601)

0.461

Duration of surgery

0.512 (0.437 to 0.587)

0.751

PMV ≥ 96-h

Age

0.554 (0.387 to 0.721)

0.498

Duration of surgery

0.588 (0.424 to 0.752)

0.268

↓ **Table 2.** Baseline Characteristic and Bivariate Analysis Toward In-Hospital Mortality
Variable	Total (n = 249)	Survivor (n = 202)	Non-survivor (n = 47)	P-value
^aCut-off was determined from ROC curve analysis. *Statistically significant results (P < 0.05). AV: aortic valve; CABG: coronary artery bypass grafting; IQR: interquartile range; MV: mitral valve; TV: tricuspid valve.
Age (years) (median (IQR))	57.00 (13.00)	56.00 (12.00)	62.00 (10.00)	0.009*
< 62 years^a	164 (65.9%)	141 (69.8%)	23 (48.9%)	0.006*
≥ 62 years	85 (34.1%)	61 (30.2%)	24 (51.1%)
Sex
Male (%)	177 (71.1%)	143 (70.8%)	34 (72.3%)	1.000
Female (%)	72 (28.9%)	59 (29.2%)	13 (27.7%)
Comorbidities
Diabetes (%)	69 (27.7%)	58 (28.7%)	11 (23.4%)	0.295
Hypertension (%)	111 (44.6%)	87 (43.1%)	24 (51.1%)	0.203
Obesity (%)	29 (11.6%)	24 (11.9%)	5 (10.6%)	0.552
Dyslipidemia (%)	33 (13.3%)	33 (16.3%)	0 (0.0%)	0.001*
Renal failure (%)	25 (10.0%)	17 (8.4%)	8 (17.0%)	0.072
Smoking (%)	68 (27.3%)	54 (26.7%)	14 (29.8%)	0.398
Type of surgery
Valve replacement (%)	72 (28.9%)	58 (28.7%)	14 (29.8%)	0.734
Single (AV/MV) (%)	56 (22.5%)	47 (23.3%)	9 (19.1%)
Double (AV + MV/MV + TV) (%)	13 (5.2%)	9 (4.5%)	4 (8.5%)
Triple (AV + MV + TV) (%)	3 (1.2%)	2 (1%)	1 (2.1%)
CABG (%)	173 (69.5%)	141 (69.8%)	32 (68.1%)
Mix (CABG + AV/CABG + MV + TV) (%)	4 (1.6%)	3 (1.5%)	1 (2.1%)
Duration of surgery (min) (median (IQR))	225.00 (79.50)	225.00 (84.00)	244.00 (110.00)	0.004*
< 280 min	203 (81.5%)	174 (86.1%)	29 (61.7%)	< 0.0001*
≥ 280 min	46 (18.5%)	28 (13.9%)	18 (38.3%)
Prolonged mechanical ventilation
24-h cut-off
≤ 24-h (%)	94 (37.8%)	85 (42.1%)	9 (19.1%)	0.002*
> 24-h (%)	155 (62.2%)	117 (57.9%)	38 (80.9%)
96-h cut-off
< 96-h (%)	235 (94.4%)	198 (98%)	37 (78.7%)	0.000*
≥ 96-h (%)	14 (5.6%)	4 (2%)	10 (21.3%)

↓ Table 2. Baseline Characteristic and Bivariate Analysis Toward In-Hospital Mortality

Variable

Total (n = 249)

Survivor (n = 202)

Non-survivor (n = 47)

P-value

^aCut-off was determined from ROC curve analysis. *Statistically significant results (P < 0.05). AV: aortic valve; CABG: coronary artery bypass grafting; IQR: interquartile range; MV: mitral valve; TV: tricuspid valve.

Age (years) (median (IQR))

57.00 (13.00)

56.00 (12.00)

62.00 (10.00)

0.009*

< 62 years^a

164 (65.9%)

141 (69.8%)

23 (48.9%)

0.006*

≥ 62 years

85 (34.1%)

61 (30.2%)

24 (51.1%)

Sex

Male (%)

177 (71.1%)

143 (70.8%)

34 (72.3%)

1.000

Female (%)

72 (28.9%)

59 (29.2%)

13 (27.7%)

Comorbidities

Diabetes (%)

69 (27.7%)

58 (28.7%)

11 (23.4%)

0.295

Hypertension (%)

111 (44.6%)

87 (43.1%)

24 (51.1%)

0.203

Obesity (%)

29 (11.6%)

24 (11.9%)

5 (10.6%)

0.552

Dyslipidemia (%)

33 (13.3%)

33 (16.3%)

0 (0.0%)

0.001*

Renal failure (%)

25 (10.0%)

17 (8.4%)

8 (17.0%)

0.072

Smoking (%)

68 (27.3%)

54 (26.7%)

14 (29.8%)

0.398

Type of surgery

Valve replacement (%)

72 (28.9%)

58 (28.7%)

14 (29.8%)

0.734

Single (AV/MV) (%)

56 (22.5%)

47 (23.3%)

9 (19.1%)

Double (AV + MV/MV + TV) (%)

13 (5.2%)

9 (4.5%)

4 (8.5%)

Triple (AV + MV + TV) (%)

3 (1.2%)

2 (1%)

1 (2.1%)

CABG (%)

173 (69.5%)

141 (69.8%)

32 (68.1%)

Mix (CABG + AV/CABG + MV + TV) (%)

4 (1.6%)

3 (1.5%)

1 (2.1%)

Duration of surgery (min) (median (IQR))

225.00 (79.50)

225.00 (84.00)

244.00 (110.00)

0.004*

< 280 min

203 (81.5%)

174 (86.1%)

29 (61.7%)

< 0.0001*

≥ 280 min

46 (18.5%)

28 (13.9%)

18 (38.3%)

Prolonged mechanical ventilation

24-h cut-off

≤ 24-h (%)

94 (37.8%)

85 (42.1%)

9 (19.1%)

0.002*

> 24-h (%)

155 (62.2%)

117 (57.9%)

38 (80.9%)

96-h cut-off

< 96-h (%)

235 (94.4%)

198 (98%)

37 (78.7%)

0.000*

≥ 96-h (%)

14 (5.6%)

4 (2%)

10 (21.3%)

↓ **Table 3.** Bivariate Analysis Toward Prolonged Mechanical Ventilation
Variable	24-h cut-off	96-h cut-off
*Statistically significant results (P < 0.05). AV: aortic valve; CABG: coronary artery bypass grafting; IQR: interquartile range; MV: mitral valve; TV: tricuspid valve.
Age (median (IQR))	57.00 (12.25)	58.00 (14.00)	0.460	57.00 (13.00)	60.50 (13.50)	0.498
Sex
Male (%)	71 (75.5%)	106 (68.4%)	0.144	167 (71.06%)	10 (71.43%)	0.621
Female (%)	23 (24.5%)	49 (31.6%)		68 (28.94%)	4 (28.57%)
Comorbidities
Diabetes (%)	19 (20.2%)	50 (32.3%)	0.027*	66 (28.09%)	3 (21.43%)	0.424
Hypertension (%)	44 (46.8%)	67 (43.2%)	0.337	106 (45.11%)	5 (35.71%)	0.344
Obesity (%)	12 (12.8%)	17 (11.0%)	0.406	28 (11.91%)	1 (7.14%)	0.498
Dyslipidemia (%)	16 (17.0%)	17 (11.0%)	0.121	32 (13.62%)	1 (7.14%)	0.422
Renal failure (%)	11 (11.7%)	14 (9.0%)	0.318	24 (10.21%)	1 (7.14%)	0.579
Smoking (%)	25 (26.6%)	43 (27.7%)	0.482	62 (26.38%)	6 (42.86%)	0.150
Type of surgery
Valve replacement (%)	26 (27.7%)	46 (29.7%)		66 (28.09%)	6 (42.86%)	0.736
Single (AV/MV) (%)	21 (22.3%)	35 (22.6%)		51 (21.7%)	5 (35.71%)
Double (AV + MV/MV + TV) (%)	4 (4.3%)	9 (5.8%)		12 (5.11%)	1 (7.14%)
Triple (AV + MV + TV) (%)	1 (1.1%)	2 (1.3%)	0.958	3 (1.28%)	0 (0%)
CABG (%)	67 (71.3%)	106 (68.4%)		165 (70.21%)	8 (57.14%)
Mix (CABG + AV/CABG + MV + TV) (%)	1 (1.1%)	3 (1.9%)		4 (1.7%)	0 (0%)
Duration of surgery (min) (median (IQR))	223.50 (85.50)	226.00 (75.00)	0.751	225.00 (74.00)	230.00 (123.25)	0.267

↓ Table 3. Bivariate Analysis Toward Prolonged Mechanical Ventilation

Variable

24-h cut-off

96-h cut-off

≤ 24-h (n = 94)

> 24-h (n = 155)

P-value

< 96-h (n = 235)

≥ 96-h (n = 14)

P-value

*Statistically significant results (P < 0.05). AV: aortic valve; CABG: coronary artery bypass grafting; IQR: interquartile range; MV: mitral valve; TV: tricuspid valve.

Age (median (IQR))

57.00 (12.25)

58.00 (14.00)

0.460

57.00 (13.00)

60.50 (13.50)

0.498

Sex

Male (%)

71 (75.5%)

106 (68.4%)

0.144

167 (71.06%)

10 (71.43%)

0.621

Female (%)

23 (24.5%)

49 (31.6%)

68 (28.94%)

4 (28.57%)

Comorbidities

Diabetes (%)

19 (20.2%)

50 (32.3%)

0.027*

66 (28.09%)

3 (21.43%)

0.424

Hypertension (%)

44 (46.8%)

67 (43.2%)

0.337

106 (45.11%)

5 (35.71%)

0.344

Obesity (%)

12 (12.8%)

17 (11.0%)

0.406

28 (11.91%)

1 (7.14%)

0.498

Dyslipidemia (%)

16 (17.0%)

17 (11.0%)

0.121

32 (13.62%)

1 (7.14%)

0.422

Renal failure (%)

11 (11.7%)

14 (9.0%)

0.318

24 (10.21%)

1 (7.14%)

0.579

Smoking (%)

25 (26.6%)

43 (27.7%)

0.482

62 (26.38%)

6 (42.86%)

0.150

Type of surgery

Valve replacement (%)

26 (27.7%)

46 (29.7%)

66 (28.09%)

6 (42.86%)

0.736

Single (AV/MV) (%)

21 (22.3%)

35 (22.6%)

51 (21.7%)

5 (35.71%)

Double (AV + MV/MV + TV) (%)

4 (4.3%)

9 (5.8%)

12 (5.11%)

1 (7.14%)

Triple (AV + MV + TV) (%)

1 (1.1%)

2 (1.3%)

0.958

3 (1.28%)

0 (0%)

CABG (%)

67 (71.3%)

106 (68.4%)

165 (70.21%)

8 (57.14%)

Mix (CABG + AV/CABG + MV + TV) (%)

1 (1.1%)

3 (1.9%)

4 (1.7%)

0 (0%)

Duration of surgery (min) (median (IQR))

223.50 (85.50)

226.00 (75.00)

0.751

225.00 (74.00)

230.00 (123.25)

0.267

↓ **Table 4.** Univariable and Multivariable Logistic Regression Analysis of Factors Associated With In-Hospital Mortality
Variable	Crude OR (95% CI)	P-value	Adjusted OR (95% CI)	P-value
*Statistically significant results (P < 0.05). Model 1: Model diagnostics: Omnibus test P < 0.0001; Hosmer–Lemeshow goodness-of-fit P = 0.859; Nagelkerke R² = 0.170. No evidence of multicollinearity was observed (all VIF < 2.0). Model 2: Model diagnostics: Omnibus test P < 0.0001; Hosmer–Lemeshow goodness-of-fit P = 0.225; Nagelkerke R² = 0.227. No evidence of multicollinearity was observed (all VIF < 2.0).
Model 1
Age (years)	1.036 (1.002 to 1.072)	0.039*	1.030 (0.994 to 1.068)	0.105
Duration of surgery (min)	1.009 (1.004 to 1.015)	< 0.0001*	1.009 (1.004 to 1.015)	0.001*
Renal failure	2.232 (0.900 to 5.538)	0.083	2.201 (0.825 to 5.871)	0.115
PMV > 24-h	3.067 (1.408 to 6.681)	0.005*	3.259 (1.438 to 7.386)	0.005*
Model 2
Age (years)	1.036 (1.002 to 1.072)	0.039*	1.037 (1.000 to 1.075)	0.049*
Duration of surgery (min)	1.009 (1.004 to 1.015)	< 0.0001*	1.009 (1.003 to 1.014)	0.002*
Renal failure	2.232 (0.900 to 5.538)	0.083	2.188 (0.820 to 5.838)	0.118
PMV ≥ 96-h	13.378 (3.983 to 44.932)	< 0.0001*	15.422 (4.112 to 57.844)	< 0.0001*

↓ Table 4. Univariable and Multivariable Logistic Regression Analysis of Factors Associated With In-Hospital Mortality

Variable

Crude OR (95% CI)

P-value

Adjusted OR (95% CI)

P-value

*Statistically significant results (P < 0.05). Model 1: Model diagnostics: Omnibus test P < 0.0001; Hosmer–Lemeshow goodness-of-fit P = 0.859; Nagelkerke R² = 0.170. No evidence of multicollinearity was observed (all VIF < 2.0). Model 2: Model diagnostics: Omnibus test P < 0.0001; Hosmer–Lemeshow goodness-of-fit P = 0.225; Nagelkerke R² = 0.227. No evidence of multicollinearity was observed (all VIF < 2.0).

Model 1

Age (years)

1.036 (1.002 to 1.072)

0.039*

1.030 (0.994 to 1.068)

0.105

Duration of surgery (min)

1.009 (1.004 to 1.015)

< 0.0001*

1.009 (1.004 to 1.015)

0.001*

Renal failure

2.232 (0.900 to 5.538)

0.083

2.201 (0.825 to 5.871)

0.115

PMV > 24-h

3.067 (1.408 to 6.681)

0.005*

3.259 (1.438 to 7.386)

0.005*

Model 2

Age (years)

1.036 (1.002 to 1.072)

0.039*

1.037 (1.000 to 1.075)

0.049*

Duration of surgery (min)

1.009 (1.004 to 1.015)

< 0.0001*

1.009 (1.003 to 1.014)

0.002*

Renal failure

2.232 (0.900 to 5.538)

0.083

2.188 (0.820 to 5.838)

0.118

PMV ≥ 96-h

13.378 (3.983 to 44.932)

< 0.0001*

15.422 (4.112 to 57.844)

< 0.0001*