Title:
Coronary Microvascular Function: Key to Improving STEMI Outcomes
Introduction:
90% of myocardial blood flow is supplied by capillary microcirculation. There is a need to restore both epicardial and microvascular flow in STEMI patients to improve prognosis. STEMI outcomes can be improved by addressing the two issues of MVO and infarct size. Studies show patients treated with SSO2 therapy had improved left-ventricular function and reduced left-ventricular remodeling when having experienced a large anterior MI.
Clinical Case:
49M with HTN, HLD and DM2 presents with severe substernal CP of 3 hours duration. EKG was concerning for anterolateral ST-segment elevations. Patient was hemodynamically stable and was loaded with DAPT. LHC showed 100% thrombotic occlusion of the pLAD. LVEDP obtained during the procedure was 35 mmhg, and LVEF 25% as seen on LV gram.
The patient underwent penumbra thrombectomy via RFA access followed by balloon angioplasty and IVUS guided DESx2. TIMI 3 flow established. SSO2 therapy, initiated within 30 minutes after PCI, for 60 minutes. Arterial pO2 prior to starting SSO2 confirmed to be >80 mmHg. 6F RFA sheath used for the PCI was exchanged for a 7F custom sheath. No evidence of a hematoma was noted. For SSO2 delivery, a SSO2 Catheter with a suitable shape, certified to provide bubble-free flow of SSO2, was advanced over a 0.035” guidewire to the aortic root via the 7F femoral sheath. Distal tip of the catheter was positioned in the ostium of the LMCA and confirmed by angiographic injection. The fluoroscopic rotation and angulation that best showed the proper catheter tip position was fixed throughout the procedure, so that brief (2-3 secs) additional fluoroscopic exposures (at 10-15 min intervals) could be used to confirm the lack of dislodgement of the catheter tip from the LMCA. TTE following day with EF of 35%, Akinesis of the mid-distal septum. Large area of apical akinesis. 3 month follow-up TTE pending. Our patient tolerated SSO2 therapy well and did not have any incidence of hemorrhagic complications.
First reported cases of SSO2 therapy use post anterior MI in the northeast Discussion:
The magnitude of LV function recovery at 3 months in patients treated with SSO2 therapy at other institutions have been robust. 3-month follow up echo pending at our institution at the time of this submission. Mechanism of LV function recovery suggested to be an immediate reversal of microvascular obstruction. Current indication for SSO2 treatment is STEMI patients undergoing primary PCI for anterior AMI presenting within 6 hours of symptom onset. Epicardial patency post PCI in MI is not enough. There is a need to address the microvasculature to further improve prognosis. SSO2 therapy has shown a clinically significant median reduction in infarct size. Infarct size and MVO directly correlate to HF and death as seen in prior studies. Studies have also shown reduced LV remodeling and improved microvascular flow after SSO2 in anterior wall MI. SSO2 therapy is the only therapy FDA-approved to specifically treat ischemic myocardium as an adjunct to reperfusion therapy with safe, consistent results from three FDA trials.