Table 1:
Best evidence papers
| Author, date and country Study type (level of evidence) |
Patient group | Outcomes | Key results | Comments |
|---|---|---|---|---|
| Al-Sarraf et al. (2008) Ann Thorac Surg, UK Retrospective cohort study (level 3 evidence) [2] |
2587 consecutive patients undergoing isolated CABG between 2000 and 2007 | Operative mortality | Current smokers: 14 (2.9%); OR 0.84 (0.44–1.63) Former smokers: 29 (2.1%); OR 0.60 (0.35–1.03) Non-smokers: 26 (3.5%); OR 1.0 (−) P = 0.168 |
Smoking is associated with significant pulmonary complications after CABG. In-hospital mortality is not influenced by smoking. Smokers should be encouraged to quit before undergoing CABG, and a period of 1 month may be beneficial, given that former smokers in this study seem to have better prognosis than current smokers |
| All operations performed through median sternotomy and use of CPB | Re-exploration | Current smokers: 23 (4.8); OR 1.07 (0.62–1.84) Former smokers: 66 (4.8); OR 1.07 (0.70–1.63) Non-smokers: 34 (4.5%); OR 1.0 (−) P = 0.950 |
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| Patients stratified into three groups: Current smokers (n = 473) Former smokers (n = 1346) (cessation >4 weeks pre-op) Non-smokers (n = 748) |
IABP and inotropic support required | Current smokers: 30 (6.3%); OR 1.02 (0.63–1.66) Former smokers: 64 (4.7%); OR 0.78 (0.52–1.16) Non-smokers: 44 (5.9%); OR 1.0 (−) P = 0.354 |
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| Ventilation >24 h | Current smokers: 22 (4.6%); OR 0.96 (0.56–1.65) Former smokers: 62 (4.5%); OR 0.94 (0.62–1.43) Non-smokers: 36 (4.8%); OR 1.0 (−) P = 0.962 |
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| Pulmonary complications | Current smokers: 143 (30.1%); OR 1.73 (1.33–2.26) Former smokers: 318 (23.3%); OR 1.22 (0.98–1.52) Non-smokers: 149 (19.9%); OR 1.0 (−) P < 0.001 |
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| Neurological complications | Current smokers: 34 (7.2%); OR 1.40 (0.88–2.25) Former smokers: 83 (6.1%); OR 1.18 (0.80–1.74) Non-smokers: 39 (5.2%); OR 1.0 (−) P = 0.377 |
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| Infective complications | Current smokers: 45 (9.5%); OR 1.27 (0.84–1.91) Former smokers: 122 (8.9%); OR 1.19 (0.86–1.65) Non-smokers: 57 (7.6%); OR 1.0 (−) P = 0.459 |
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| Renal complications (requirement for dialysis) | Current smokers: 9 (1.9%); OR 0.89 (0.55–1.44) Former smokers: 34 (2.5%); OR 1.13 (0.79–1.61) Non-smokers: 23 (3.1%); OR 1.0 (−) P = 0.417 |
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| Gastrointestinal complications | Current smokers: 18 (3.8%); OR 1.69 (0.86–3.32) Former smokers: 50 (3.7%); OR 1.64 (0.94–2.86) Non-smokers: 17 (2.3%); OR 1.0 (−) P = 0.181 |
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| Readmission to ICU | Current smokers: 19 (4.0%); OR 1.91 (0.97–3.75) Former smokers: 43 (3.2%); OR 1.49 (0.83–2.66) Non-smokers: 16 (2.1%); OR 1.0 (−) P = 0.163 |
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| Mean ICU stay (days) | Current smokers: 1.8 ± 3.2 Former smokers: 2.0 ± 4.6 Non-smokers: 2.3 ± 5.0 P = 0.144 |
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| Mean postoperative stay (days) | Current smokers: 8.9 ± 10.5 Former smokers: 9.2 ± 11.9 Non-smokers: 9.9 ± 16.5 P = 0.078 |
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| Blood transfusion | Current smokers: 166 (34.9%); OR 0.68 (0.54–0.86) Former smokers: 511 (37.5%); OR 0.76 (0.63–0.91) Non-smokers: 330 (44.1%); OR 1.0 (−) P = 0.002 |
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| Jones et al. (2011) Interact CardioVasc Thorac Surg, UK [3] Retrospective cohort study (level 3 evidence) |
1108 patients undergoing cardiac surgery between 2002 and 2007 | Overall population: Operative mortality |
Current smokers: 24 (4.3%) Never smokers: 13 (2.3%) P = 0.067 |
The current data strengthen the observation that preoperative smoking is predictive of adverse outcomes of cardiac surgery in the elderly, and pulmonary complications may exert a significant effect on outcome |
| CABG: 63.4% Valve: 23.1% CABG + valve: 10.1% Other procedures: 3.4% |
Pulmonary complication | Current smokers: 60 (11.0%) Never smokers: 37 (6.8%) P = 0.01 |
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| Patients stratified into two groups: Current smokers (n = 554) Never smokers (n = 554) |
ICU re-admission | Current smokers: 38 (6.9%) Never smokers: 22 (4.0%) P = 0.03 |
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| The two groups were sub-stratified Current smokers: ≤70 years (n = 473) >70 years (n = 81) Never smokers: ≤70 years (n = 360) >70 years (n = 194) |
Infection | Current smokers: 176 (31.8%) Never smokers: 122 (22.0%) P < 0.001 |
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| New renal replacement | Current smokers: 31 (5.6%) Never smokers: 23 (4.2%) P = NS |
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| Blood transfusion | Current smokers: 336 (60.1%) Never smokers: 360 (65.1%) P = NS |
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| Re-exploration | Current smokers: 30 (5.4%) Never smokers: 35 (6.3%) P = NS |
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| Stroke | Current smokers: 13 (2.4%) Never smokers: 6 (1.1%) P = NS |
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| Mean ventilation, h (range) | Current smokers: 8.9 (0–640) Never smokers: 8.2 (0–46) P = NS |
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| Mean ICU stay, days (range) | Current smokers: 3.6 (0–60) Never smokers: 2.5 (0–75) P = NS |
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| >70 years cohort: Operative mortality |
Current smokers: 12 (14.8%) Never smokers: 4 (2.1%) P < 0.0001 |
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| Pulmonary complication | Current smokers: 20 (24.7%) Never smokers: 16 (8.2%) P = 0.0002 |
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| ICU re-admission | Current smokers: 16 (19.8%) Never smokers: 10 (5.2%) P = 0.0002 |
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| Infection | Current smokers: 36 (44.4%) Never smokers: 46 (23.8%) P < 0.0007 |
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| New renal replacement | Current smokers: 14 (17.3%) Never smokers: 6 (3.1%) P < 0.0001 |
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| Blood transfusion | Current smokers: 57 (70.4%) Never smokers: 139 (71.6%) P = NS |
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| Re-exploration | Current smokers: 4 (4.9%) Never smokers: 14 (7.2%) P = NS |
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| Stroke | Current smokers: 4 (4.9%) Never smokers: 5 (2.6%) P = NS |
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| Mean ventilation (h) (range) | Current smokers: 76.1 (0–22) Never smokers: 37.5 (0–46) P = 0.026 |
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| Mean ICU stay, days (range) | Current smokers: 6.2 (1–60) Never smokers: 2.8 (0–66) P = 0.002 |
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| Ngaage et al. (2002) Cardiovasc Surg, UK [4] Retrospective cohort study (level 3 evidence) |
2163 patients undergoing elective cardiac surgery between 1993 and 1999 |
Operative mortality | Smokers: 4.2% Ex-smokers: 3.2% Non-smokers: 2.8% |
Active smokers have a comparatively poor postoperative respiratory outcome after cardiac surgery. The duration of mechanical ventilation has a direct impact on the risk of postoperative pulmonary complications |
| CABG: 1579 (73%) Valve: 372 (17.2%) CABG + valve: 212 (9.8%) |
Mean ICU stay (h) | Smokers: 60 Ex-smokers: 34 Non-smokers: 31 P < 0.005 |
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| Patients stratified into three groups: Smokers (n = 207) Ex-smokers (n = 1075) (cessation >3 months pre-op) Non-smokers (n = 881) |
Postoperative pulmonary complications: | Smokers: 29.5% Ex-smokers: 14.7% Non-smokers: 13.6% P < 0.002 |
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| Atelectasis | Smokers: 10.6% Ex-smokers: 5.2% Non-smokers: 4.8% |
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| Chest infection | Smokers: 7.2% Ex-smokers: 1.9% Non-smokers: 2.1% |
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| Pleural effusion | Smokers: 3.9% Ex-smokers: 4% Non-smokers: 3.9% |
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| ARDS | Smokers: 3.4% Ex-smokers: 1.3% Non-smokers: 1.4% |
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| Mean duration of mechanical ventilation, h | Smokers: 16 Ex-smokers: 7.9 Non-smokers: 8.3 P < 0.012 |
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| Sternal wound infection | Smokers: 15% Ex-smokers: 11% Non-smokers: 15% |
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| Mediastinitis | Smokers: 2.4% Ex-smokers: 1.4% Non-smokers: 1% |
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| Arabaci et al. (2003) Jpn Heart J, Turkey [5] Prospective cohort study (level 3 evidence) |
213 consecutive patients undergoing elective isolated CABG |
Postoperative arterial blood gas analysis: PaO2 (mmHg) |
Smokers: 66.1 ± 8.0 Non-smokers: 69.1 ± 8.9 P = 0.0091 |
Preoperative evaluation of the pulmonary status of patients with a history of smoking who are scheduled for elective revascularization surgery is important, and that smoking cessation should be strongly encouraged performed preoperatively as early as possible in order to minimize postoperative respiratory complications |
| All operations performed through median sternotomy and use of CPB |
PaCO2 (mmHg) | Smokers: 38.6 ± 3.6 Non-smokers: 32.0 ± 4.7 P < 0.0001 |
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| Patients stratified into two groups: Smokers (n = 117) Non-smokers (n = 96) (cessation >20 years pre-op) |
pH | Smokers: 7.4 ± 0.1 Non-smokers: 7.4 ± 0.1 P = NS |
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| Postoperative pulmonary function tests: VC (L) |
Smokers: 2.3 ± 0.4 Non-smokers: 2.7 ± 0.4 P < 0.0001 |
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| FVC (L) | Smokers: 2.4 ± 0.5 Non-smokers: 2.8 ± 0.4 P < 0.0001 |
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| FEV1 (L) | Smokers: 1.7 ± 0.4 Non-smokers: 2.1 ± 0.2 P < 0.0001 |
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| FEV1/FVC | Smokers: 72.2 ± 11.5 Non-smokers: 76.0 ± 9.8 P = 0.0110 |
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| Intubation period (h) | Smokers: 19.9 ± 11.5 Non-smokers: 14.1 ± 4.3 P < 0.0001 |
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| ICU stay (days) | Smokers: 3.2 ± 1.3 Non-smokers: 2.4 ± 0.6 P < 0.0001 |
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| Hospitalization period (days) | Smokers: 14.1 ± 4.4 Non-smokers: 12.5 ± 2.4 P < 0.0013 |
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| Pulmonary complications: Atelectasis |
Smokers: 5 (4.3%) Non-smokers: 2 (2.1%) |
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| Pleural effusion | Smokers: 11 (9.4%) Non-smokers: 4 (4.2%) |
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| Chest infection | Smokers: 8 (6.8%) Non-smokers: 4 (4.2%) |
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| Total | Smokers: 24 (20.5%) Non-smokers: 10 (10.4%) |
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| Sanchez-Lazaro et al. (2007) Transplant Proc, Spain [6] Retrospective cohort study (level 3 evidence) |
288 patients undergoing heart transplantation between 1987 and 2006 | Survival rate | Smokers: 81.63% Ex-smokers: 92.11% Non-smokers: 89.57% P = 0.031 |
Patients who smoke or have smoked until shortly before heart transplantation show a poorer prognosis and a higher rate of early pulmonary complications after heart transplantation The deleterious effects of smoking are progressively reduced as the interval between smoking cessation and transplantation increases |
| Patients stratified into three groups: Smokers (n = 49) Ex-smokers (n = 76) (cessation < 1 year pre-op) Non-smokers (n = 163) (cessation >1 year pre-op) |
Mean intubation time, h | Smokers: 14.2 ± 7.3 Ex-smokers: 33.4 ± 44.6 Non-smokers: 17.9 ± 19.2 P = 0.05 |
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| Mean ICU stay, days | Smokers: 4.4 ± 1.88 Ex-smokers: 7.9 ± 10.5 Non-smokers: 4.84 ± 3.49 P = 0.021 |