UNPROTECTED LEFT MAIN STEM CAD MANAGEMENT : SURGERY OR PCI?

When I was in medical school, CAD was treated by medical therapy, and any attempt at intervening or instrumenting the coronary artery was deem heresy and punishable as professional negligience. Well sometime in 1965, while trying to inject dye into the aortic root in a patient with aortic valve disease, the catheter that Dr Mason Sones placed in the root of the aorta accidentally fell into the right coronary artery and besides an aortogram, he also did a right coronary angiogram. He watched in horror as the patient's heart rate fall and BP fall, and then slowly stabilised. The patient survived the RCA angiogram. Dr Sones then realised that you could safely take angiogram pictures of coronary arteries with selective coronary artery cannulation. Of course, Dr sones was working in the Cleveland Clinic and his surgical colleague there was pioneering a procedure called coronary artery bypass graft surgery, where selective coronary angiogram would prove invaluable both for diagnosis and also to assist the planning of CABG. Of course Dr Sones colleague was the famous pioneer cardiac surgeon called Dr Rene Favaloro of Argentina.
Then we fast forward till September 15th 1977, when Dr A Greuntzig successfully dilated an LAD stenosis in a Swiss dentist. This further proved that the goal post has moved again. That it was safe ( with all the appropriate training and precautions ) to safely work within coronary arteries. This began the journey of "percutaneous coronary interventions ". One by one, the goal post moved. Initially, Dr Greuntzig only advocated angioplasty ( as the new procedure was initially called ) for single lesion CAD. Then with better equipment and devices we began to do two vessels and then three vessels disease, much to the chargrin of our cardiac surgeons. The goal post was moving and still is. Coronary interventionist, ably led by the Korean Dr SJ Park and the French, Dr Jean Marco and Fajadet, began to take on left main stem disease, initially in the protected left main ( left main disease with a good functioning bypass graft ), and later in unprotected left main stem disease ( isolated ) and gradually to left main stem in the context of other vessel disease. Left main stem disease post a significan challenge because of the severe myocardium at risk. Surfice to say that in any given individual, the left main stem controls the blood supply to the whole of the left ventricle and in many cases even some myocardium of the right ventricle. Therefore, should there be any mishaps, cardiac death was inevitable. In other words, the margin for error was minimal. When the work was being done by Dr Park and Dr Fajadet, there was much surgical protest. They felt that we were killing our patients and that surgery ( CABG ) was the only option in left main stem ( LMS ) disease. However, Dr Park. Fajadet and Marco, was able to show that they they could do LMS PCI safely and with good short and medium term results apart from repeat revascularisation from restenosis. Then came along the Drug Eluting Stents that would reduced restenosis. With that, large clinical trials were done to compare CABG and PCI in left main stem disease. Sme of these trails were done with the cooperation of cardiac surgeons who also wanted to know how their technique compared. The results with PCI proved almost comparable. The goal post is moving again.
This blog is written partly in response to the paper in the Oct 20th issue of the Journal of the American College of Cardiology, by a group of expert interventionist, calling for a review of the PCI guidelines in America. They argued that there was enough evidence now accumulated to justify making LMS PCI a class 2 a or class 2 b indication. This paper's lead author is Dr David Kandzari of Scripps Clinic, La Jolla California.
A word about the guidelines.
A class 3 indication for a treatment procedure means that the treatment procedure have not been shown to be of benefit and may be of some harm. A Class 2 indication means that the treatment procedure maybe of benefit. Class 2 b means that this statement is attested to be the opinion of kep opinion leaders and class 2 a means that there is good clinical evidence, besides that of key opinion leaders. Of course a class 1 indication means that that treatment method is obviously of benefit for that condition and that that should be the treatment of choice.
At the moment, the USA guidelines has put LMS PCI as a class 3 indications, and that it should be undertaken only if the patient is not fit for CABG or refuses CABG. However across the big pond, the European Cardiac Society had LMS PCI as a class 2b indication. Now Dr Kandzari and colleagues felt that it is time ( in the face of the body of evidence ) to review the USA guidelines ( call it shift the goal post ) too include LMS PCI as a class 2 b indication, and for those with just isolated LMS disease without concomitant other vessel disease, a class 2a indication. Afterall, we have recently seen the published results of the all important SYNTAX trial, the ISAR Left Main trial, and the MAIN COMPARE trial. There is another large Asian trial, the COMBAT, whose results is yet to be published.
In my opinion the call by Dr Kandzari and colleagues is not unreasonable. As usual, there are no perfect guidelines. Guidelines are only as good as those who use them. The practitioner / interventionist, is very important. LMS PCI is a very complex and delicate angioplasty technigue and there are many judgement calls along the way, to keep out of trouble. As we said initially, the margin for error is small, and I have seen beautifully done LMS PCI that turned sour within hours in the ward. A certain degree of competence is required. I have no problem with Dr SJ Park, Dr Fajadet and Marco do LMS PCI. I am just not sure if the avaerage Malaysian interventionist can. Therein lies the danger. I attend many live demo and PCI courses and have seen many LMS PCI cases presented. I sometimes shatter at the cases some junior interventionist take on. Afterall, one must not forget that there are some interventionist out there who would dilate for bread. And I am very worried for that. Anyway, I do not wish to be judge and jury. I am writing to highlight that the Oct 20th JACC call, means that the goal post may be moving again.
Soon there will be much less indication for CABG. What shall the cardiac surgeons do? In USA trhe number of doctors undergoing cardiac surgical training has dropped. The goal post is indeed moving and the cardiac scene is changing.