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Relevant clinical history and physical exam
A 69 year-old woman with a history of treated hypertension, presented with sudden onset chest pain, at rest, and evidence of ST-segment elevation in the inferior leads of a 12-lead electrocardiogram. Thus, urgent coronary angiography was performed.
Relevant test results prior to catheterization.
Relevant catheterization findings
Urgent coronary angiography demonstrated a normal left coronary system but an abrupt lumen calibre reduction extending from segment 2 of the RCA into the PDA, with preserved TIMI-3 flow and the PL branch of the RCA was sub-totally occluded (file 1).
We proceeded to evaluate the RCA with OCT. Imaging was challenging due to catheter-induced complete luminal occlusion and consequent difficulties clearing the imaging field of blood, however, dissection is observed at the level of the external elastic membrane with a low attenuation area observed behind the collapsed intima-media complex (file 2A and B). The collapsed intima-media complex may be misinterpreted as a ‘diseased’ segment but measurement of the medial area and comparison with a normal reference segment confirms equivalent areas and strengthens the diagnosis of intramural compression, particularly when observed in associated with luminal contour folding (file 2C-F).
The patient suffered a transient worsening of chest pain and ST-segment changes while the OCT catheter was distally occlusive. Interpretation of the angiographic and OCT findings suggested a diagnosis of spontaneous coronary artery dissection (SCAD) without intimal disruption and led us to take a relatively conservative strategy (POBA) of the mid and distal segments of the RCA to enhance distal flow. Angiographic assessment post-POBA, revealed evidence of an iatrogenic dissection in the mid vessel, with preserved TIMI-3 flow in all branches (file 3). At this time, the patient was hemodynamically stable and asymptomatic, therefore further intervention was avoided. Repeated angiography, on day 7, demonstrated improved luminal calibre in the affected segments and re-canalisation of PL branch (file 4).
Immediate angiographic assessment of patients presenting with STEMI has increased the interventional communities’ awareness of non-atherosclerotic causes for myocardial injury. Furthermore,intravascular imaging, with optical coherence tomography (OCT), has facilitated the detection of spontaneous coronary artery dissection (SCAD), where angiographic assessment has previously been ambiguous. Detection of these atypical aetiologies facilitates acute, patient-tailored, therapy and may guide further risk reduction. We present a case of SCAD confirmed by OCT and consider the impact of this diagnosis.