SS–05 A Case of Inferior Myocardial Infarction Due to Catheter-Induced Dissection During RCA FFR Assessment

Abstract

Introduction and Aim: Fractional flow reserve (FFR) is a widely used and reliable method for assessing the functional significance of coronary artery stenoses. However, rare but life-threatening complications such as coronary dissection, spasm, or acute thrombotic occlusion may occur during the procedure. In this case, we present a catheter-induced dissection of the right coronary artery (RCA) that occurred during FFR assessment in the setting of coronary angiography, followed by acute thrombotic total occlusion, and its management with percutaneous coronary intervention, temporary pacemaker support, and thrombolytic therapy.

Case Report: A 54-year-old female patient presented to the cardiology outpatient clinic with exertional dyspnea. Coronary computed tomography revealed coronary artery disease, and she was hospitalized for coronary angiography. Angiography demonstrated 70-80% stenosis in the proximal RCA. The decision was made to assess the severity of the RCA lesion with FFR (Fig. 1). After the FFR pressure wire was advanced distal to the lesion, the patient developed sudden ST-segment elevation and complete atrioventricular (AV) block. Imaging revealed acute total occlusion of the RCA due to a dissection originating from the proximal segment, with a heavy thrombus burden, and the patient sustained an inferior myocardial infarction during the procedure (Fig. 2). The lesion was crossed with a guidewire, and repeated predilations were performed with a 3.0×30 mm balloon. Because of complete AV block, a temporary pacemaker was placed via the right femoral vein. Intracoronary adrenaline was administered for no-reflow. A 4.0×38 mm drug-eluting stent was implanted in the RCA. A second 4.5×12 mm drug-eluting stent was placed at the RCA ostium, overlapping with the first stent. TIMI 2-3 flow was achieved after proximal optimization, and a 12-hour glycoprotein IIb/IIIa inhibitor infusion was initiated (Fig. 3). The patient's rhythm converted from complete block to normal sinus rhythm. On the same day, the patient's general condition deteriorated during follow-up, and complete AV block recurred, prompting a second angiographic evaluation. TIMI 1 flow and dense thrombus were observed in the RCA. Intracoronary alteplase 10 mg was administered over 10 minutes. Although TIMI 3 flow was subsequently achieved, findings consistent with residual thrombus or dissection extending from the mid segment to the distal vessel persisted. The patient then received a 25 mg intravenous alteplase infusion over 24 hours. A third coronary angiography performed two days later showed complete resolution of the thrombosed dissection area distal to the stent, with preserved distal TIMI 3 flow (Fig. 4). The proximal in-stent segment was optimized by high-pressure dilation with a 4.5×15 mm non-compliant balloon. During follow-up, the patient remained in sinus rhythm and hemodynamically stable, and she was discharged on medical therapy.

Conclusion: Acute thrombotic total occlusion secondary to dissection occurring during FFR assessment of the RCA is a rare but life-threatening complication that can result in inferior myocardial infarction, complete atrioventricular block, and severe flow impairment. Prompt recognition of electrocardiographic changes and conduction disturbances during the procedure, together with immediate angiographic evaluation, temporary pacemaker support, and timely percutaneous coronary intervention, is of vital importance. In selected cases with refractory and persistent thrombus burden, intracoronary and intravenous alteplase therapy may help restore normal coronary flow while avoiding repeat stent implantation.