Coronary artery disease: PTCA: patients who kept smoking were more likely to have an MI or die.

Clinical bottom line (level 1b)

  1. Patients who continued to smoke after successful percutaneous coronary revascularization were at greater risk for death from any cause or for Q-wave myocardial infarction than non-smokers (NNF = 9 for 4.5 years) .
  2. Fewer smokers or quitters go on to have repeat angioplasty or CABG.
  3. Patients who gave up smoking more than six months before revascularisation were still at increased risk of dying (NNF = 21 for 4.5 years) compared with non-smokers.
  4. Stopping smoking after revascularisation had no clear effect on death, but reduced the likelihood of repeat revascularisation (NNF = -20 for 4.5 years) and CABG (NNF = -23 for 4.5 years) .
Hasdai et al: New England Journal of Medicine 1997; 336 (11): 755-761
Expires June 2003

The study

Inception cohort study with objective outcomes, adjusted for confounding factors, not validated in an independent set of patients.

Setting: university hospital USA

5450 patients (aged mean 64 years, 74% male) clinically successful percutaneous coronary revascularisation, defined as reduction of >20% in stenosis of >1 lesion and a residua stenosis of <50% without in-hospital complications of death, Q-wave MI, or need for coronary artery bypass graft (CABG)

Excluded if
  • acute MI within 24 hours of the procedure
  • started to smoke during follow-up
  • death, Q-wave MI, CABG in hospital




    • Multivariate analysis was performed to adjust for confounding factors.

    99% followed for 1 to 16 years (mean 4.5)
    Outcomes studied:
  • death
  • Q-wave MI
  • severe angina
  • repeat revascularisation
  • CABG

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    death 1 to 16 years (mean 4.5) 777/5437 14.3%
    (13.4% to 15.2%)
    Q-wave MI 1 to 16 years (mean 4.5) 94/5437 1.73%
    (1.38% to 2.08%)
    severe angina 1 to 16 years (mean 4.5) 2198/5437 40.3%
    (39.1% to 41.7%)
    repeat revascularisation 1 to 16 years (mean 4.5) 1391/5437 25.6%
    (24.4% to 26.7%)
    CABG 1 to 16 years (mean 4.5) 848/5437 15.6%
    (14.6% to 16.6%)

    prognostic factor for
    death     		time to outcome adjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    persistent smoker 1 to 16 years (mean 4.5) 1.76
    (1.37 to 2.26)     		9
    (6 to 19)
    former smoker 1 to 16 years (mean 4.5) 1.34
    (1.14 to 1.57)     		21
    (12 to 50)
    quitters 1 to 16 years (mean 4.5) 1.21
    (0.87 to 1.70)     		33
    (-54 to 10)

    prognostic factor for
    Q-wave MI     		time to outcome adjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    persistent smokers 1 to 16 years (mean 4.5) 2.08
    (1.16 to 3.72)     		54
    (21 to 362)
    former smokers 1 to 16 years (mean 4.5) 1.28
    (0.77 to 2.16)     		210
    (-250 to 50)
    quitters 1 to 16 years (mean 4.5)
    ( to )     		130
    (-160 to 27)

    prognostic factor for
    severe angina     		time to outcome adjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    persistent smokers 1 to 16 years (mean 4.5) 0.98
    (0.86 to 1.12)     		-124
    (-18 to 21)
    former smokers 1 to 16 years (mean 4.5) 0.99
    (0.90 to 1.09)     		-250
    (-25 to 28)
    quitters 1 to 16 years (mean 4.5) 0.91
    (0.76 to 1.08)     		-28
    (-10 to 31)

    prognostic factor for
    repeat revascularisation     		time to outcome adjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    persistent smokers 1 to 16 years (mean 4.5) 0.67
    (0.56 to 0.81)     		-12
    (-21 to -9)
    former smokers 1 to 16 years (mean 4.5) 0.93
    (0.83 to 1.05)     		-56
    (-23 to 78)
    quitters 1 to 16 years (mean 4.5) 0.80
    (0.64 to 0.98)     		-20
    (-200 to -11)

    prognostic factor for
    CABG     		time to outcome adjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    persistent smokers 1 to 16 years (mean 4.5) 0.68
    (0.54 to 0.86)     		-20
    (-46 to -14)
    former smokers 1 to 16 years (mean 4.5) 0.95
    (0.81 to 1.11)     		-130
    (-34 to 58)
    quitters 1 to 16 years (mean 4.5) 0.72
    (0.54 to 0.95)     		-23
    (-130 to -14)

    • Risk factors were compared with non-smokers, who had never smoked.

    Comments

    1. Smokers were younger and had more favourable clinical and angiographic profiles- despite this, more died.
    2. There is no clear explanation why smokers or quitters have lower reintervention rates than non-smokers.
    3. Overall, this study supports earlier studies that quitting smoking either before or after the development of coronary disease reduces cardiac morbidity and mortality.

    Citation

    1. Hasdai D, Garratt KN, Grill DE, et al: Effect of smoking status on the long-term outcome after successful percutaneous coronary revascularization. New England Journal of Medicine 1997; 336 (11): 755-761
    Search Terms: PTCA in Best Evidence
    Contributor: Chris Ball and Clare Wotton, June 2000
    Reviewer: Chris Rembold

    Clinical Question.
    Patient successful revascularisation
    Intervention or Exposure smoking
    Outcome death, MI, angina