Coronary bypass surgery and coronary angioplasty: Competitors or companions?

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cedures. Circulation 1988:78;486-502. Tamai H, Park S J, Plokker T, et al. Directional atherectomy or stenting for unprotected left main coronary stenoses - the ULTIMA group experience. J Am Co11 Cardiol 1998;31(supplA):1033-102. 27. Umans VA, Melkert R, Foley DP, et al. Clinical and angiographic comparison of matched patients with successful directional coronary atherectomy or stent implantation for primary coronary artery lesions. J Am Co11 Cardiol 1996;28;637-644 JD, Ellis SG, Pieper K, et al. The CAVEAT-I investi28. Boehrer gators. Directional atherectomy versus balloon angioplasty for coronary ostial and non-ostial left anterior descending coronary artery lesions: results from a randomized multicenter trial. J Am

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Coronary Bypass Surgery And Coronary Angioplasty: Competitors or Companions? Peter Ruygrok,

FRACP,

FESC

Cardiology Department, Green Lane Hospital, Auckland, New Zealand both techniques? Two years? Five years? Ten years? These trials determine outcome in terms of major adverse cardiac events, namely death, myocardial infarction and repeat revascularisation. Does it remain appropriate to label repeat angioplasty a major adverse cardiac event?

Introduction Coronary bypass surgery has now been with us for more than 3 decades. The Vineberg operation was superseded by saphenous vein grafting and more recently by arterial bypass grafting. The morbidity and mortality of surgery has dramatically diminished through refinements in myocardial protection, anaesthesia, extacorporeal circulation and assisted circulatory support. The complexity of patients accepted for surgery has increased, not only in terms of their cardiac status but also with respect to comorbidity. This has partially occurred as a result of the evolution and maturation of percutaneous coronary angioplasty. The spiral springs of Charles Dotter and the crude balloons of Andreas Greuntzig were the predecessors of the stents and balloons we use today with relative ease and speed. Angioplasty is perceived as being less invasive and causes less damage to other organ systems than surgery, is easily and indefinitely repeatable, and the prevention of the final obstacle - restenosis - may be imminent. The surgeons are achieving better immediate term outcomes, a reduction in need for reoperation with the widespread use of arterial grafts, and are developing less invasive techniques, including the elimination of extracorporeal circulation.

Randomised Trials Nine randomised trials have studied the outcome of balloon angioplasty compared with coronary bypass surgery. They all differ with regard to entry criteria and recruited patient demographics such as number of diseased vessels, proportion with unstable angina and diabetes, upper age limit and length of follow-up. Large numbers of patients were screened, with less than 10% recruited into these studies, most having been rejected by the interventionist. This implies far greater selectivity for those undergoing angioplasty and clearly demonstrates that results of these studies can only be applied to those patients with clinical and angiographic characteristics similar to the entry requirements for these studies rather than to the general coronary artery disease population. These trials have shown that there is no difference in death and myocardial infarction during hospitalisation and mid-term follow-up. Surgical patients required a longer hospitalisation and convalescence, but had a greater relief of symptoms and required less medication and subsequent revascularisation procedures than those who underwent angioplasty.

Aspects of Surgery and Angioplasty Through data gathered from observational studies and randomised trials, patients with coronary artery stenoses have been segregated into 2 groups, those for surgery and those for angioplasty. Before reviewing the randomised trials, it is fitting to reflect on some aspects of such studies. At what stage of procedural evolution should a randomised study be undertaken? If too soon, expertise and technique may still be maturing. If too late, it may be considered unethical to randomise. What is an adequate period of follow-up that is fair to

Impact of Coronary Stenting Two major randomised trials, the Arterial Revascularisation Therapy Study (ARTS) which has completed recruitment of 1,200 patients and the Stents or Surgery study (SOS) which has recruited more than onethird of the desired 1,000 patients, are underway. Trials of minimally invasive surgery have also commenced. The Otto-stent randomised study, which compares the outcome of stenting with surgery using the Octopus

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device, eliminating the need for cardiopulmonary bypass, has recruited more than 10% of the required 280 patients.

anatomical and physiological assessment techniques such as intravascular ultrasound, Doppler and pressure wires will aid in optimising the results of angioplasty procedures. Perhaps we should begin thinking in terms of what combinations of treatment are most appropriate for a particular patient at a particular stage of his or her atherosclerotic coronary disease. Comparisons of surgical to angioplasty techniques may be nearing an end and be replaced by investigations of hybrid therapies employing the most beneficial aspects of both techniques. Are we about to enter an era of coronary artery surgery with angioplasty stand-by? It seems clear that coronary artery surgery and angioplasty are destined to remain companions well into the next millennium.

The Future Refinements in surgical technique continue, with smaller incisions, the elimination of bypass with the consequent benefits of reduced neurological and renal morbidity, and thus shorter hospital stays. The use of arterial grafts promises to abolish the lo-year fall-off in surgical survival curves. Angioplasty awaits the panacea for restenosis. The use of brachytherapy and gene therapy via local delivery with agents such as endothelial growth factor may become common-place along with administration of novel antiplatelet agents. The continuing development of

Vein Graft Stenosis: A Personal Approach Paul McEniery,

FRACP, FACC

Department of Cardiology, The Prince Charles Hospital, Brisbane, Queensland, Australia Introduction Nowhere in interventional cardiology does the old adage “You can’t make a silk purse out of a sow’s ear” apply more than in the approach to percutaneous revascularisation of saphenous vein grafts, particularly those more than seven years old. Case selection is of paramount importance in determining the benefits of a percutaneous approach and ensuring good long-term outcome. Dilatation of saphenous vein grafts constitutes about 3% of my practice, similar to published experience with stent implantation.1 It is wise to consider surgical consultation in determining a joint approach to vein graft disease. Where the coronary circulation is graft dependent and the vein graft disease afflicts all grafts, particularly in patients operated on before the frequent use of internal thoracic artery grafts, better long-term outcomes may be associated with repeat surgical therapy.

vein graft disease. The Toulouse group has recommended perhaps a week of aspirin, ticlopidine and subcutaneous low-molecular-weight heparin prior to approach to such disease. A novel approach to reconstruction of diseased saphenous vein grafts with “autologous tissue-coated stents” has been advocated, with experimental evidence of no thrombosis and minimal intimal hyperplasia.2 I have no experience with this approach, but the idea is exciting. Use of abciximab (ReoPro, Eli Lilly) reduces the incidence of distal embolisation during balloon angioplasty of old saphenous vein grafts from 18% to 2%.3 Prevention of compromise of distal collaterals by vasoconstrictive elements in embolised thrombus may be part of the beneficial effect of abciximab administration. Oral platelet glycoprotein IIbflIIa receptor blockers are eagerly awaited. Angiography Angiographic definition of the problem is important prior to commencement of balloon angioplasty. For example, the eye may be led to a severe mid-graft stenosis but not appreciate the significant proximal disease that may prevent the passage of the stent. It is occasionally necessary, therefore, to dilate and stent more proximal and less severe disease in order to approach more distal and severe disease. Angiographic definition is particularly important in assessment of skip grafts where the eye may be fixed on the stenosis to be dilated but miss the fact that a more proximal stenosis is actually totally occluded with the proximal branch filling by collaterals or a direct connection from the branch subtended by the stenosis to be dilated. A larger amount of myocardium may therefore be in jeopardy than was first appreciated.

Advances in Treatment Advances in pharmacology have made the approach to vein graft disease safer. Clinically and intuitively, there is a difference between the expected response of a discrete lesion in an otherwise normal-looking vein graft, which may not be older than a few years (following implantation), and the diffuse irregular thrombus-laden disease of older vein grafts. In the latter case, discretion may sometimes be the better part of valour. Medical treatment of thrombotic vein graft disease with the combination of warfarin and aspirin without intervention or with surgical revascularisation may occasionally be preferable. The Washington group has advocated anticoagulation with warfarin for 4 weeks prior to treatment of thrombotic

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