Can medical mangement convert a patient with positive stress test into negative ?
Posted Oct 16 2009 10:01pm
Exercise stress test is the most commonly used non invasive diagnostic test for CAD.
It is also useful in the functional capacity evaluation.Even though medical management of CAD is a proven and accepted method of therapy in CAD . There is always a perception even among the cardiologists medical management is an inferior form of treatment. This is primarily due to peer group pressure rather than based on solid scientific concepts.
What is the effect of medical management on the common CAD parameters ?
Relief of angina . It is a simple , and easy parameter to assess.
Functional capacity . Increased exercise capacity is a good marker of successful medical therapy
The effect on stress ischemia could be most objective way to assess the success of medical therapy.
But , unfortunately this does not come in the regular scheme of things for many cardiologists following medical management. If we are able to document reversal of stress test positivity it could be the ultimate marker of success in medical revascularisation. EST is an approved method of assessment of efficacy of optimal medical management .Still , in day to day cardiology practice this is rarely done for the simple reason the patient often stumbles upon an interventionist and lands up in a PCI or CABG !
Following things can happen over EST following medical management
Complete correction of inducible ischemia
Delayed appearance of ST depression with increased exercise capacity
Duration of ST depression can be reduced
Convert painful ischemia into silent ischemia*
No response **
* Conversion of painful episodes into silent episodes may not be a real success in physiological terms.But in patient point of view it is .It should be recalled even in CABG pain relief is a major clinical outcome .
** Could be termed as failure of medical management , but there is a group of patients who have increased exercise capacity but still EST is positive
Real world experience of large case studies (Individual communication : Large community based stress test in over 9000 patients ( Gnanavel et all Ganesh clinic Thiruvannamalai ,India ) strongly suggest optimal medical management would indeed reverse exercise induced ST depression.
Why can’t we call medical therapy as a revascularisation procedure ?
Human mind does not accept certain things. Simply swallowing few drugs can never make us believe ( Especially the current generation cardiologists ! ) it can be equivalent to a PCI/CABG
While , restoration of TIMI flow , % stenosis , Net luminal gain, are the popular scientific parameters fro effective revascularisation , the following are the desired outcomes clinical well being , relief from pain, reduction of plaque volume, plaque stabilisation, maintenance of collaterals , microvascular patency , reduction of recurrent events .The irony in CAD management is in many points clinical endpoints can be achieved without mechanical the above mechanical end points !( As we learn from the OAT, COURAGE trials where we learn t arterial patency is nothing to do with major clinical end points )
While PCI and CABG inherently convey they are revascularsation procedures , realistically looking medical therapy also does improve the vascularisation espcially where it is needed (Micro)
In the overall interest of CAD community , and with good scientific basis , it is vital to emphazise medical management of CAD is also a form revascualrisation .It is better to call OMT(Optimal medical therapy ) as medical revascularisation .This will help us to neutralise the unfair” semantic advantage” the PCI and CABG enjoys as revascularisation modalities !
Refer: 1.AVERT study :Atorvastatin equals PCI .2.Regular excercise equivalent to PCI (esc2009)
Medical management , do reverse the positive EST in most of the patients provided the drugs are optimally used
Stability provided by medical management in coronary micro and macrocircualtion is often significant and it can either directly or indirectly improve coronary perfusion . attenuate ischemia , improve exercise capacity and relieve symptoms. To confirm this , every patient with medical management should periodically undergo exercise stress testing.
* One may argue , without knowing coronary anatomy it is dangerous to assume things and every patient with positive EST should udergo CAG. Yes , It may be true, ischemia due to critical lesions in proximal locations can never be corrected with drugs