We know acute coronary syndrome presents* with either STEMI or NSTEMI. (*It actually doesn’t present , it is our understanding and interpretation ). Bifurcating ACS into two is more by convention and convenience .Does the intra-coronary plaque dynamics really permit us to divide ACS in to two distinct ECG entities ?
Are we oversimplifying it ? Probably yes.
The following paper was presented in the cardiological society annual scientific session in New Delhi few years ago (2006)
It generated an intense debate , finally the chair person reluctantly concluded such events are possible. . .
but need more proof . What is your take on this issue ?
DUAL ACUTE CORONARY SYNDROME
Department of cardiology . Madras Medical College. Chennai
Acute coronary syndrome (ACS) is classified into STEMI and NSTEMI and has gained universal acceptance. The classification was done by clinical & electro physiological findings with some pathological basis. The classification came into vogue primarily to simplify the decision making process of thrombolysis. ( STEMI –Thrombolysis eligible .NSTEMI Thrombolysis ineligible.) The limitation of this classification is well exposed as we now know, STEMI can evolve into NSTEMI and NSTEMI can evolve into STEMI . Identifying the culprit artery in ACS is not straight forward especially in NSTEMI. Adding further complexity is the newer observations that diffuse vessel inflammation, and multiple active plaques(MAP) are responsible for many of the episodes of ACS.
In this scenario there could be two are more pathological processes one resulting in a total occlusion and other sub total occlusion resulting in both patterns of ACS simultaneously .(STEMI & NSTEMI Dual ACS)
We describe two patients who had presented to our CCU . Both had STEMI one in lateral other in anterior wall . They were thrombolysed as per criteria. Both patients had gross ST depression (>4mm) elsewhere. In one patient it corresponded to the reciprocal leads .The outcome of thrombolysis was turbulent .Both patients worsened and one developed recurrent VT . Paradoxically the ST elevation regressed indicating a successful thrombolysis in the STEMI territory even as the ST depression was worsening in the other leads. Angiogram revealed multivessel CAD with recannalised LAD lesion with eccentric , thrombus containing lesion in RCA/LCX. One patient expired and other was referred for revascularisation.
We believe both of our patients experienced Dual ACS.
When to suspect dual ACS ?
Dual ACS is likely , when STEMI is associated with ST depression in at least 5mm in any two leads or when there is disproportionate reciprocal ST depression ( > 2mm of primary). The reason for the poor outcome could be due to a therapeutic conflict between STEMI & NSTEMI as the former is thrombolysis friendly while the later is not . Role of thrombolysis in such situations were ACS wanders between STEMI & NSTEMI is not defined. Another possibility is the concept of reciprocal ST elevation, where in the index event could be NSTEMI and STEMI is a secondary response and thrombolysis is apparently contraindicated.
We conclude that in patients with ACS, two or more plaques can simultaneously get activated and present as a combination of STEMI / NSTEMI in the same patient in two different coronary arteries.(Dual ACS) .We suggest that in every patient who present with STEMI a possibility of dual ACS is to specifically considered, as thrombolysis could be disastrous and instead they should reach the cath lab directly. .