Angina: refractory: transmyocardial revascularisation reduced cardiac events and hospitalisation

Clinical bottom line (level 1b)

  1. Patients with medically-refractory angina who received transmyocardial revascularisation compared with medical therapy were less likely to fail treatment (NNT = 4 at 12 months) .
  2. Patients given transmyocardial revascularisation were less likely to have a cardiac event (NNT = 4 at 12 months) or be admitted to hospital with a cardiac problem (NNT = 4 at 12 months) , but not clearly less likely to die.
Allen et al: N Engl J Med 1999; 341 : 1029-1036
Expires January 2004

The study

Single-blinded ?concealed randomised trial with intention-to-treat
Setting: 18 acute hospitals, USA

275 patients (aged mean 60, 75% male) with medically-refractory class IV angina (on maximum tolerated doses) due to coronary disease who could not be treated with percutaneous or surgical revacularisation

Excluded if
  • severe COPD (FEV1 < 55% predicted)
  • need for continued use of iv antianginal medication
  • unable to undergo dipyridamole-thallium scintigraphy
  • non-Q wave MI within previous 2 weeks; or Q-wave MI within previous 3 weeks
  • need for long-term anticoagulant therapy
  • presence of ventricular mural thrombus
  • severe arrhythmias
  • no reversible ischaemia within distal two-thirds of left ventricle
  • LV ejection fraction < 25%, or decompensated heart failure
  • contraindication to general anaesthesia

Control Group: (n = 143, 143 analysed): medical therapy
Experimental Group: (n = 132, 132 analysed): transmyocardial revasularization followed by continued medical therapy

99% followed for 12 months
Outcome notes:
  • treatment failure : death, myocardial infarction, 3 cardiac-related hospitalisations, inability to withdraw from iv antianginal medication on 2 attempts within 48 hours

The evidence

Outcome Time to outcome CER EER RRR
(95% CI)		 ARR
(95% CI)		 NNT
(95% CI)
treatment failure 12 months 76
(53.2%)		 36
(27.3%)		 49%
(29% to 63%)		 25.9%
(14.7% to 37.0%)		 4
(3 to 7)
death 12 months 16
(11.2%)		 21
(15.9%)		 -42%
(-160% to 22%)		 -4.72%
(-12.8% to 3.38%)		 -21
(NNT = 30 to infinity;
NNH = 8 to infinity)
cardiac event 12 months 99
(69.2%)		 61
(46.2%)		 33%
(17% to 46%)		 23.0%
(11.6% to 34.4%)		 4
(3 to 9)
hospitalised with cardiac problem 12 months 96
(67.1%)		 51
(38.6%)		 33%
(17% to 46%)		 23.0%
(11.6% to 34.4%)		 4
(3 to 6)

Comments

  1. Patients were randomised in blocks of six at each centre.
  2. Patients received a mean of 39 +/- 11 channels during transmyocardial revascularisation.
  3. 32% of medically-treated patients could not be weaned off iv medication and subsequently underwent transmyocardial revascularisation. Data on improvement in angina symptoms was confounded since these patients were included in the treatment group for this analysis.

Citation

  1. Allen KB, Dowling RD, Fudge TL, et al: comparison of transmyocardial revascularization with medical therapy in patients with refractory angina. N Engl J Med 1999; 341 : 1029-1036
Search Terms: from ACP Journal Club other articles noted
Contributor: Chris Ball, January 2002
Reviewer:

Clinical Question.
Patient medically-refractory angina
Intervention or Exposure transmyocardial revascularisation
Comparison medical therapy
Outcome death, myocardial infarction, hospitalisation