CAN THERE BE SMOKE WITHOUT FIRE? THE ORBITA TRIAL CONTROVERSY
MIMER Medical College
The ORBITA trial, I’m sure you have heard a lot about it, but let’s start from scratch. What was this trial, and what were the inferences drawn from it?
The ORBITA trial was a randomized trial of Percutaneous Coronary Intervention (PCI) versus a placebo procedure for angina relief in patients with severe single vessel stenosis. The participants first received medication optimization after which pre randomization assessments were done. These tests broadly evaluated the exercise capacity and symptoms of the participants. They were then randomized in a 1:1 ratio to undergo either PCI or a placebo procedure. These two groups were re assessed after a follow up period of 6 weeks. The results of this trial were what baffled the cardiac community and brought this trial into the public eye, where it faced both critical acclaim as well as strong rejection. Clearly, the participants who had undergone PCI were expected to have had a better symptom relief as well as improved exercise capacity in comparison to their counterparts. However, this was not the case and in a strange twist in the tale, it was found that, there was no significant difference in the reassessment results of the two groups of individuals.
The results of this trial raised a few serious questions. Was the need for operational intervention genuine, or was it mere capitalization on part of the medical community?
The investigators of the trial have put forth their views by saying that PCI has shown symptom relief in angina patients but this has never been proven through a blinded Randomized Controlled Trial, to which cardiologists have argued that the benefit of PCI depends upon several patient variables which cannot be generalized as done by the said study. According to guidelines, medication optimization is done with anti anginal drugs before resorting to interventional measures. However, in clinical practice how often is this followed? Moreover, can one set of guidelines be applicable to all patients? And how well are the patients informed about the benefits of any interventional procedure that is done? Does the patient truly have a choice as to whether he wants to opt for the surgery? Perhaps not. According to me, they literally see the situation as do or die. Further, to the lay man, drastic measures such as one of operational intervention obviously sounds more reassuring as compared to popping pills. Therefore, first and foremost, it is important that the patient is well aware of the severity of his condition, as well as all the treatment options available to him, along with the clinician’s take on the recommended approach. When asked about the trial, several cardiologists had interesting insights to offer. For instance, it is important to bring to attention that the trial dealt only with patients of stable angina, who constitute a relatively low risk population as compared to patients of unstable angina and ischemia. Therefore, it is imperative to understand that the findings of this study cannot be extrapolated to patients with more severe symptoms or those who can actually significantly benefit from PCI. Another thought provoking argument from the cardiac community is regarding the period of the trial. Many have argued that 6 weeks is not sufficient time to increase the exercise duration in the given PCI group which started with an already good enough baseline. Further, the placebo did not show any effect on the exercise duration either. Obviously, the reason for the selection of a low risk population and a shorter study duration was to reduce the risk of leaving the lesions non-revascularised for longer periods of time.
There have been several arguments that have been put forth, some have been for, while others have been against this trial. According to me, I do not think that one can see this issue as black and white, because the answers lie in shades of grey. This trial personifies ambiguity at its best and differentiating standpoints in an argument while labelling one as right and the other wrong would be unfair to both the founders of the trial as well as interventional cardiologists world over.