SCMR 22nd Annual Scientific Sessions
Description of Clinical Presentation:
76-year-old male with a history of coronary artery disease with prior CABG 12 years prior and multiple percutaneous interventions, ischemic cardiomyopathy with estimated left ventricular EF 30-40% by echocardiography presented with a complaint of exertional angina despite aggressive antianginal medical therapy. Patient was referred for outpatient regadenoson stress CMR for further evaluation.
Diagnostic Techniques and Their Most Important Findings:
CMR was performed on 1.5T Siemens Aera MRI scanner. Resting long axis cine images were performed first. Pre-stress HR was 73bpm, and BP of 137/76. The patient then received 0.4 mg IV push of regadenoson. After 60 seconds, stress perfusion imaging was obtained with 5ml/second injection of 0.075mmol/kg of gadobenate dimeglumine. Post-vasodilator long axis cine images were obtained immediately afterwards, followed by short axis stack cine. Peak HR achieved was 104 bpm with a BP of 121/72. The remaining 0.075mmol/kg of gadobenate dimeglumine was given, and late gadolinium enhancement images were taken 10 minutes afterwards. After regadenoson injection, the patient developed chest pain, but did not inform staff. He was transferred to the emergency department. ECG demonstrated no significant ST depression. He was given aspirin, enoxaparin, and nitroglycerin, and his chest pain subsided. Serial troponin were 0.09 ng/mL, 0.27 ng/mL, 0.68 ng/mL, consistent with a type 2 NSTEMI.
Resting cine images revealed hypokinesis of the anterior and anteroseptal walls with a left ventricular EF of 46%, EDV of 170mL, ESV of 92mL. Global longitudinal strain by feature tracking was -14.9%. Stress perfusion images demonstrated a severe transmural perfusion defects in the basal to distal anterior, anteroseptal and inferoseptal wall. Post-vasodilator cine left ventricular EF decreased to 36% with EDV of 202mL, ESV of 128mL. Global longitudinal strain by feature tracking was -11.2%. LGE images showed subendocardial enhancement in the anterior and septal walls
Invasive angiography revealed stenting of the entire LAD artery. There was a severe ostial lesion, with instent restenosis. The obtuse marginal stent was patent, and the RCA was diffusely diseased. The only patent bypass graft was a saphenous vein to the RCA. There was no revascularization target seen in the LAD. Patient remains on medical therapy for angina.
Learning Points from this Case:
Vasodilator stress CMR has been shown to have better sensitivity and negative predictive values as compared with single photon emission computed tomography imaging. It is shown to be safe, and have minor side effects. Our case demonstrates a rare phenomenon of coronary steal causing dilation of the left ventricle, decreased ejection fraction and global longitudinal strain as detected by CMR, as well as elevated biomarkers. In vasodilator stress CMR clinical trials, there has not been a reported case of myocardial infarction caused by regadenoson. There have been reported cases of myocardial infarction after regadenoson in SPECT imaging.