Interactive Cardiovascular and Thoracic Surgery 3:581-585(2004)
© 2004 European Association of Cardio-Thoracic Surgery
Best evidence topic - Cardiac general |
Is transmyocardial revascularisation of benefit in addition to coronary artery bypass grafting for patients with diffuse coronary disease?
Aliu Sanni and
Joel Dunning*
Department of Cardiothoracic Surgery, Freeman Hospital, Freeman Road, Newcastle upon Tyne NE7 7DN, UK
* Corresponding author. Tel./fax: +44-780-154-8122. (E-mail: joeldunning{at}doctors.org.uk).
Received June 22, 2004;
accepted June 28, 2004
 |
Abstract
|
|---|
A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether the use of transmyocardial revascularisation (TMR) in addition to coronary artery bypass grafting (CABG) is of benefit in patients with ischaemic heart disease with areas of ungraftable myocardium. Altogether 233 papers were found using the reported search, of which 9 represented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses were tabulated. We conclude that while the society of thoracic surgeons now recommend TMR+CABG, and the available studies indicate that mortality is not increased by this additional procedure, it is currently not clear whether TMR reduces symptoms of angina in addition to CABG alone.
|
1. Introduction
|
|---|
A best evidence topic was constructed according to a structured protocol. This protocol is fully described in the ICVTS [1]
|
2. Clinical scenario
|
|---|
You are operating on a 67 year old diabetic who has had 4 years of gradually worsening angina. He currently has CCS grade IV angina and has told you that he has no quality of life and is desperate for something to be done. The angiogram shows a 90% proximal LAD stenosis, a 70% circumflex stenosis but with diffuse disease down the artery and down a small obtuse marginal artery. A perfusion scan demonstrated clear areas of reversible ischaemia anteriorly and laterally. The right coronary artery is occluded, with backfilling of a small PDA. At operation the LAD is graftable and the PDA is severely diseased but you find a small area where a graft can be placed. However the circumflex territory has no graftable vessels. You know that there is reversible ischaemia in this territory and a colleague has a Holmium:YAG laser next door. You elect to perform transmyocardial revascularisation (TMR) to the circumflex territory, prior to placing the grafts, but you resolve to review the literature to check that you have not unnecessarily increased the risk of mortality for this patient, and that this additional procedure might improve the chances or resolving your patient's angina.
|
3. Three-part question
|
|---|
In [patients with diffuse coronary artery disease undergoing CABG] is the use of [transmyocardial revascularisation in addition to CABG] of any benefit in terms of [angina relief or survival]?
|
4. Search strategy
|
|---|
Medline 1966-March 2004 using the OVID interface [TMR.mp OR TMLR.mp OR DMR.mp OR Transmyocardial.mp OR exp laser surgery/] AND [exp coronary artery bypass/ OR coronary bypass.mp OR CABG.mp]
|
5. Search outcome
|
|---|
A total of 233 abstracts were found from Medline of which 8 were directly relevant. In addition a systematic review recently published by the STS as a guideline for the use of TMR with or without CABG as treatment for refractory angina was included. These are presented in Table 1.
|
6. Results
|
|---|
Allen et al. in 2000 [2] performed a Multicentre PRCT with 263 patients. Patients had one or more viable target areas not amenable to CABG. They found only 2 patients died in the TMR+CABG group compared to 10 in the CABG alone group which was a significant finding. Furthermore the 7.6% mortality in the CABG alone group was similar to that predicted by parsonnet score. This survival benefit remained out to 12 months follow up. Unfortunately no benefit in terms of angina or improved exercise treadmill performance was shown. Of note, while this was a well conducted study, areas of reversible ischaemia were not established pre-operatively.
Trehan et al. [3;4] published 2 cohort studies of 104 patients who had CABG and TMR and 56 patients who had off pump TMR+CABG. They had only 3 deaths and 87% of patients were angina free at one year. However due to the lack of a control group, they could not establish that their results were due to the TMR rather than the CABG, and thus only acceptable mortality can really be noted from this study.
Loubani et al. in 2003 [5] performed a single centre PRCT in 20 patients comparing CABG alone with TMR+CABG. There were no deaths and they found a considerably improved exercise tolerance at 6 months and 18 months. However, this benefit was lost at 36 months and in addition there were no differences seen in angina score at any stage, and no measurable echocardiographic improvements. It must be noted that this was a very small study with only 10 patients in each group.
Vincent et al. [7] reported a retrospective cohort of 268 ‘no option’ patients, who underwent TMR using carbon dioxide laser revascularization, 128 of whom also underwent CABG. They reported a 12% operative mortality in the TMR+CABG group, with 13% of patients needing an IABP and an 8% re-operation for bleeding rate. They did report that 84% of TMR+CABG patients and 40% of TMR alone patients had either CCS grade 0 or 1 angina at one year, but this was assessed by the operating surgeons and thus should be read with caution.
Stamou [8] reported their 1 year findings after combined TMR+CABG in 169 patients operated on by a single surgeon. They had an 8% mortality, but they reported that whereas 90% of patients had CCS grade III-IV angina pre-operatively, only 7% still had this level of angina at one year. However, this single surgeon series had no control group and no independent assessment of angina scoring, and thus the findings that may have been achieved without TMR are unknown in this cohort.
Burns et al. in 1999 [6] reported the results of an international registry which was set up in 1994 to collect data on this emerging procedure. They reported 932 procedures from 15 centres, including 177 combined CABG+TMR procedures. Although they provided no breakdown of the combined CABG+TMR cohort, they found an overall 10% mortality, 30% complication rate and only 34% of patients had an improvement of CCS class of more than 2 classes at 12 months.
Peterson et al. in 2003 [9] compared current clinical practise of TMR+CABG and TMR alone as reported in the STS database from the USA with those results from clinical trials. They found that as of 2001, 36% of US centres now perform TMR procedures, mostly combined with CABG, and that there has been a large expansion in this procedure nationally even though CABG+TMR is not FDA approved. They furthermore found no difference in mortality between CABG alone (4.9%) and CABG+TMR (4.1%). They had no data on post-operative angina scoring, and they could not reliably compare CABG+TMR with incomplete revascularisation by CABG which would have been a fairer comparison. However, the two most important findings here are that CABG+TMR is now widespread in the USA and it is not associated with an increased mortality as compared to CABG alone.
Bridges et al. [10] have recently published the first of a series of guidelines from the society of thoracic surgeons. This guideline was on the use of TMR, and TMR+CABG. They reviewed the same papers that are summarized here and concluded that although there was divergence of opinion, the balance of evidence favoured TMR+CABG in patients undergoing CABG where there was an area of reversible ischaemia, with the area not amenable to bypass either because of diffuse disease, lack of suitable targets, or lack of suitable conduit. Guidelines such as these usually have a great impact on practise, but it is interesting to note that no mention of the lack of FDA approval was made and both Keith Allen, and Keith Horvath, major advocates of TMR were on the guideline committee. However, it was a well balanced document and weaknesses in the literature were addressed.
While TMR+CABG is now recommended by the society of thoracic surgeons in America, the available studies do not conclusively find that angina is significantly reduced by adding TMR to CABG. There does, however, consensus that it does not seem to increase mortality in these patients
|
7. Clinical bottom line
|
|---|
While the society of thoracic surgeons now recommend TMR+CABG, and the available studies indicate that mortality is not increased by this additional procedure, it is currently not clear whether TMR reduces symptoms of angina in addition to CABG alone.
doi:10.1016/j.icvts.2004.06.011
|
References
|
|---|
- Dunning J, Prendergast B, Mackway-Jones K. Towards evidence-based medicine in cardiothoracic surgery: best BETS Interact Cardiovasc Thorac Surg 2003;2:405-409.[Abstract/Free Full Text]
- Allen KB, Dowling KB, DelRossi AJ, Realyvasques F, Lefrak EA. Transmyocardial laser revascularization combined with coronary artery bypass grafting: a multicentre, blinded, prospective, randomized controlled trial J Thorac Cardiovasc Surg 2000;119:540-549.[Abstract/Free Full Text]
- Trehan N, Mishra M, Bapna R, Mishra A, Maheshwari P, Karlekar A. Transmyocardial laser revascularisation combined with coronary artery bypass grafting without cardiopulmonary bypass Eur J Cardio-thorac Surg 1997;12:276-284.[Abstract]
- Trehan N, Mishra M, Kohli A, Bapna R. Transmyocardial laser revascularisation as an adjunct to CABG Indian Heart J 1996;48:381-388.[Medline]
- Loubani M, Chin D, Leverment JN, Galinanes M. Mid-term results of combined transmyocardial laser revascularization and coronary artery bypass Ann Thorac Surg 2003;76:1166.
- Burns SM, Sharples LD, Tait S, Caine N, Wallwork J, Schofield PM. The transmyocardial laser revascularization international registry report Eur Heart J 1999;20:31-37.[Abstract/Free Full Text]
- Vincent JG, Bardos P, Kruse J, Maass D. End stage coronary disease treated with the transmyocardial CO2Laser revascuilarisation: a chance for the inoperable patient Eur J Cardiothorac Surg 1997;11:888-894.[Abstract]
- Stamou SC, Boyce SW, Cooke RH, Carlos BD, Sweet LC, Corso PJ. One-year outcome after combined coronary artery bypass grafting and transmyocardial laser revascularization for refractory angina pectoris Am J Cardiol 2002;89:1365-1368.[CrossRef][Medline]
- Peterson ED, Kaul P, Kaczmarek RG, Hammill BG, Armstrong PW, Bridges CR, Ferguson B. From controlled trials to clinical practise: monitoring transmyocardial revascularization use and outcomes J Am Coll Cardiol 2003;42:1611-1616.[Abstract/Free Full Text]
- Bridges CR, Horvath KA, Nugent WC, Shahian DM, Haan CK, Shemin RJ, Allen KB, Edwards FH. The society of thoracic surgeons practice guidelines series: transmyocardial laser revascularization Ann Thorac Surg 2004;77:1494-1502.[Abstract/Free Full Text]
|
|
Top
Abstract
1. Introduction