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primary angioplasty-is it affordable to the masses in the developing countries
- dr.ashim aggarwal (21 May 2004)
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Trying to understand the validity of the different arguments
- Jeffrey Mann (21 May 2004)
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Early response is essential
- Mervyn s. Gotsman (22 May 2004)
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Stranded at Sea
- Sharif Hossain (24 May 2004)
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Primary angioplasty - some logistical considerations
- Roger Gamon (28 June 2004)
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dr.ashim aggarwal, clinical attachment james paget hospital,great yarmouth
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respected author your article is really good but in developing countries like india where about 40-50percent of the population is below the poverty line is primary angioplasty really cost effective and affordable. i really dont think so.but what i really want to emphasise is the fact that though advances are being made in the field of medicine some weightage should be given to the cost effectiveness of the procedure so that it becomes available to the masses.only then can there be a significant decrease in the mortality and morbidity. Competing interests: None declared |
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Jeffrey Mann, Retired physician Salt Lake City, UT 84103
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In this week's issue of the bmj (22 May 2004) there are three articles discussing the issue of whether primary angioplasty is better than thrombolysis as first line treatment of acute myocardial infarction. For angioplasty as first line treatment -- Smith -- http://bmj.bmjjournals.com/cgi/content/full/328/7450/1254 Against angioplasy as first line treatment -- Channer -- http://bmj.bmjjournals.com/cgi/content/full/328/7450/1256 Bogaty/Brophy -- humorous commentary -- http://bmj.bmjjournals.com/cgi/content/full/328/7450/1257 Am I understanding their positions correctly, and are the figures used in their arguments accurate? For argument: Smith argues that-: "Thrombolysis (the current first line treatment) is pharmacological, can be applied to only 60-80% of the presenting population, fails to make a definitive diagnosis, and leaves the treatment goal unconfirmed. Coronary angioplasty, on the other hand, is mechanical, can be applied to any patient, is guided by an accurate definitive diagnosis, and results in certainty about the therapeutic end point. Primary angioplasty carries no risk of inappropriate treatment and a low risk of serious complications whereas thrombolysis can be used inappropriately in up to 10% of presenting patients and has an appreciable risk of producing disabling stroke." I presume that Smith regards the primary therapeutic endpoint as "opening up the occluded coronary artery" and not an improvement in mortality rates and/or long-term myocardial function. Is he correct to state that primary angioplasty carries no risk of inappropriate treatment? Can one always identify the culpit lesion causing the AMI, or is there a chance that one could perform angioplasty on a stenotic coronary artery that is not specifically the primary cause of the AMI? Smith then argues as follows-: "Let us consider the use of thrombolysis in 100 patients presenting with ST elevation myocardial infarction. About 25% of patients are ineligible because of late presentation, bleeding history, hypertension, etc, and some have treatment stopped prematurely because of reactions such as hypotension and allergy. Of the 75 patients who receive treatment 24 (32%) can expect to have normal coronary flow restored if streptokinase is used or 40.5 (54%) if alteplase is used. Of these, about 10% would have had spontaneous reperfusion and will have therefore received thrombolysis unnecessarily. On this basis between a quarter (streptokinase) and a half (alteplase) of patients presenting achieve the therapeutic goal without undue risk." Do you agree with Smith's figures that 10% of patients would have spontaneous recanalisation without treatment, and that alteplase only increases that figure to 54%? Do you accept his argument that, overall, only 40% of AMI patients, who present to hospital with a ST segment elevation AMI, would expect to end up with a patent coronary artery if an angioplasty service is not available? Smith then argues in favor of primary angioplasty as follows-: "If primary angioplasty is used for the 100 patients, no patient is exempt and the diagnostic angiogram can usually identify the infarct related artery and assess the state of coronary perfusion. Treatment can then be given to those patients who have not reperfused spontaneously, and normal epicardial blood flow is likely to result in 90-97% of attempted angioplasties. With this approach, the therapeutic goal is achieved and documented in more than 90% of patients with no unnecessary risk." Smith first states that a diagnostic angiogram can usually identify the infarct related artery. What does the word "usual" mean? What is the accuracy rate of identifying the infarct related artery? He then states that angioplasy is 90-97% successful in achieving patency. Does this 90-97% figure apply to continued patency, or do a certain percentage of patent vessels re-occlude post-angioplasty as a result of mechanical (angioplasty-induced) trauma to the vessel wall? What is the percentage rate of angioplasty-induced secondary peri-infarctions? Smith then argues that-: "Twenty three randomised trials have compared primary angioplasty with thrombolysis. A meta-analysis of these trials concludes that primary angioplasty has a highly significant benefit over thrombolysis for mortality, non-fatal reinfarction, and haemorrhagic stroke. None of these 23 trials suggests a trend in favour of thrombolysis, although only one trial individually shows a mortality benefit in favour of primary angioplasty." What does a "highly significant" benefit mean considering that Smith supplies no numbers to support his statement? He then states that only one trial showed a mortality benefit in favor of angioplasty. Does that mean that the other 22 trials were neutral from a mortality perspective? Against angioplasty: Channer first states-: "Thrombolysis is the established treatment for patients with an acute ST segment elevation myocardial infarction based on large trials in the past two decades. Studies show that treatment within an hour after onset of symptoms results in a 6.5% absolute reduction in mortality compared with placebo; this benefit falls quickly with time to 3.7% at 1-2 hours, 2.6% at 2-3 hours, 2.9% at 3-6 hours, 1.8% at 6-12 hours, and 0.9% at 12-24 hours. However, thrombolysis also causes an absolute increase in stroke of 0.4% (half of which are fatal), an absolute increase of 0.7% in major non-cerebral bleeds, and a 3% increase in early non-fatal reinfarction. Although thrombolysis saves lives in hospital, it has no later benefits; the survival curves of patients given placebo or thrombolysis exactly superimpose after 35 days, or even after discharge from hospital. The mechanism for the reduction in hospital mortality is unclear since all causes of death are reduced. It is not accounted for by a reduction in infarct size because this effect is small (6% at 4 days and only 2% at 10-28 days), and a reduction in infarct size would confer a long term survival advantage, which is not seen." Is Channer correct to state that although thrombolysis decreases the hospital mortality rate by a small percentage (0.9%-6.5% depending on timing), that there is no long-term mortality benefit? Channer then emphasises the fact that there is no long-term mortality benefit as a result of vessel patencty when he states-: "Large randomised trials comparing different thrombolytic drugs with differing early patency rates showed no mortality benefit from patency. If a difference in patency were important, then a difference in long term prognosis would have been expected, but this has not been seen. The move to primary angioplasty is driven by the holy grail of infarct related artery patency but the evidence that it affects hospital mortality is limited? Channer then specifically quotes a meta-analysis to support his position that angioplasty-induced vessel patency offers little benefit by stating-: "A recent meta-analysis of over 7000 patients showed an absolute 2% improvement in mortality for patients having angioplasty; fewer patients had early non-fatal reinfarction, recurrent ischaemia, and strokes." Is Channer correct -- do clinical studies show little significant benefit from primary angioplasty in optimum treatment settings (hospital centres involved in clinical trials)? Channer then infers that the results would be even less satisfactory in community hospitals, because of a delay in primary angioplasty treatment. Channer specifically argues as follows-: "The earlier studies were mainly done in centres of excellence, but a large Danish study could be used as a model for implementation in the United Kingdom. In this study, patients were transferred from district general hospitals to regional centres for primary angioplasty; there was no significant mortality benefit compared with on-site thrombolysis, and the only benefits were in recurrent ischaemia requiring intervention and reinfarction. Although these events have been argued to affect survival, early placebo controlled thrombolysis trials showed that the increase in reinfarction after thrombolysis was not associated with increased early or late mortality. Moreover, the Danish study did not count reinfarction after angioplasty, further biasing against thrombolysis. Thus, the only relevant comparator for the two treatment strategies is all cause mortality, which was not reduced by angioplasty in the study." Channer subsequently argues that further studies confirm the lack of benefit in community practice, and he states-: "Of more importance for the United Kingdom, interventionalists in the United States have been unable to replicate the trial results, and registry data recording the results of primary angioplasty in practice show less benefit than expected from the trials. This is explained by the delays incumbent in this approach, which requires clinical evaluation in the emergency room and then transfer to a cardiac catheterisation laboratory, coronary angiography, and angioplasty. ---- A meta-analysis of published randomised trials shows that when the time delay related to angiography (that is the door to balloon minus the door to needle time) exceeds 60 minutes, the mortality benefits of primary angioplasty over thrombolysis are lost. For every 10 minute delay, there is a 1% reduction in the composite end point of death, reinfarction, or stroke, so that by 90 minutes there is no measurable difference between primary angioplasty and immediate thrombolysis." Do you agree with Channer's argument? If Channer is correct, would an approach based on pre-hospital thrombolysis (very early thrombolysis) offer better mortality results than primary angioplasty?
Competing interests: None declared |
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Mervyn s. Gotsman, Professor of Cardiology Hadassah University Hospital, Jerusalem, Israel
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All the current studies have shown that the extent of myocardial necrosis is related to the speed with which the culprit artery is occluded, the time delay to reopening of the artery and the efficacy of the reperfusion.
We pioneered home thrombolysis which shortens the time delay between arterial occlusion and reopening and reduces infarct size. This improves the short and long term mortality.
Primary angioplasty, particularly with stenting and powerful antiplatelet medication improves the speed of reperfusion at the cost of time delay in finding a vacant, available aniography unit.
Nonetheless it is more effective than chemical thrombolysiis provided that the system can provide a time delay of no more than 2 hours from pain onset to effective arterial reperfusion.
The clock is ticking.
Competing interests: None |
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Sharif Hossain, SHO Medicine Isle Of Wight, PO30 5TG
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Primary angioplasty may well prove to be the gold standard for treatment of ST elevation MIs (STEMIs) in the future, but for the moment I foresee a great deal of factors against angioplasty, especially highlighted working on the Isle of Wight, the main one being the post code lottery. Although this has already been mentioned with an average door to balloon times of 1 hour and 56 minutes, but these studies were conducted in the US, where distances to centres that can perform angiolpasties can be quite different to that of the UK. Additionally, the Isle of Wight is unique in that a vehicle ferry is required to transport patients to a tertiary referral centre. Door to balloon times are hence significantly greater than 1 hour as the crossing itself is 55 minutes alone. I cannot see angioplasties ever becoming the gold standard until primary angioplasty centres are developed in District General Hospitals, requiring both time, money and investment in angiography skills and laboratories. Something the NHS perhaps lacks? In the interim period, meantime, surely the way forward would be to reduce door to needle times, and consider pre-hospital thrombolysis as a more practical approach? Competing interests: None declared |
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Roger Gamon, Service Improvement Manager Greater Manchester & Cheshire CHD Collaborative, Room 210, Gateway House, Manchester, M60 7LP
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Dr Smith puts forward a good argument for the use of primary angioplasty to treat patients with ST elevation myocardial infarction (STEMI). Logistical considerations would, of course, need to be considered if this were to become standard practice. One such consideration – though certainly not an argument against such a service per se – is, I believe, the notion of ‘immediate eligibility’. Ostensibly, if primary angioplasty were the standard treatment for STEMI, all patients currently thrombolysed would be transported from the community to a tertiary centre for intervention instead of being taken to the local District General Hospital (DGH) as is usually the case currently. However in my experience, and others [1, 2] only around 48-59% patients are immediately eligible for thrombolysis, according to standard classification [3], on admission to hospital. Reasons for immediate ineligibility may include lack of manifest ST elevation (not developed at that point in time), equivocal nature of any existing ST changes thus necessitating repeat electrocardiogram(s), and/or presence of a relative risk. If primary angioplasty was the first line treatment then these factors could impact on the ability of paramedics in the field to make decisions regarding the most suitable destination for such patients; DGH or tertiary centre? It is certainly the case that, using telemetry and 2-way radio, some of these issues could be overcome at the paramedic/tertiary centre interface. However, unless there were a blanket ‘all cardiac chest pains to tertiary centre’ policy, it seems inevitable that some patients who subsequently develop criteria for reperfusion will initially be taken to the DGH. The question is how should these patients be treated? Should another ambulance be called and the patient be transferred for angioplasty? This would obviously add some delay to treatment, which may or may not be deemed acceptable. Alternatively, should the patient be thrombolysed on site (perhaps before transfer), bearing in mind the probable deskilling, in terms of thrombolysis administration, of Emergency Department staff which would follow a national primary angioplasty strategy? Whilst, these questions relate to patients who are brought to the hospital via an ambulance, in our experience [4] approximately a quarter of patients given thrombolysis self-presented to the Emergency Department. Similar logistical considerations pertain to this sub-group of patients. To re-iterate, these are not arguments against primary angioplasty. However, as there are only relatively few centres that can currently provide the service, such considerations are surely important. Note: these are the personal opinions of the author. References 1. Gamon R, Driscoll P, Cooper A, Barnes P, Parr B. Can Emergency Department-initiated thrombolysis supported by a Thrombolysis Co-ordinator reduce treatment times? Care of the Critically Ill journal. 2002;18:104- 106. 2. Quinn T, Allan TF, Birkhead J, Griffiths R, Gyde S, Murray RG. Impact of a regionwide approach to improving systems for heart attack care: the West Midlands thrombolysis project. European Journal of Cardiovascular Nursing 2003; 2, 131-139. 3. Birkhead JS, Norris RM, Quinn T, et al, on behalf of the Coronary Heart Disease National Service Framework Steering Group. Acute myocardial infarction: a core data set for monitoring standards of care. London: Royal College of Physicians, December, 1999. 4. Gamon R, Harte D, Barnes N, Higham P & Lecky F. Courtesy calls: Roger Gamon and colleagues describe how courtesy calls to myocardial infarction teams can reduce door-to-needle times. Emergency Nurse 2004;12(30):20-23. Competing interests: None declared |
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