Author + information
- Gustavo Jimenez-Brítez1,
- Carlos Robles2,
- Manel Sabate3,
- Ignacio Amat-Santos4 and
- Salvatore Brugaletta5
Takotsubo syndrome (TS) is a clinical syndrome characterized by a reversible left ventricular dysfunction in absence of epicardial coronary obstruction. Although several pathogenic mechanisms have been proposed (e.g. multivessel epicardial spasm, catecholamine-induced myocardial stunning, spontaneous coronary thrombus lysis, and acute microvascular spasm) its causes are still unknown. In our study we sought to perform a functional and morphological assessment of left anterior descending artery (LAD) in TS patients, by using optical coherence tomography (OCT) and flow wire.
From January 2016 to May 2017, 14 consecutive TS patients, admitted at two Institutions and defined accordingly to Mayo Clinic diagnostic criteria (1), were included. A flow wire (Certus, St Jude) was introduced in LAD at the level of second diagonal branch. After induction of hyperemia with adenosine (140 mcg/kg/min), fractional flow reserve (FFR) and index of microcirculation reserve (IMR) were measured. FFR and IMR were considered abnormal if < 0.80 and > 22, respectively. The OCT acquisition was then performed using a commercially available system for intra-coronary imaging on the LAD (at least 50 mm) during continuous injection of contrast through the guide catheter with an injection pump. Presence of coronary plaque on OCT pullback was analyzed offline by 2 independent investigators.
Thirteen patients (92.8%) were woman, with a mean (SD) age of 66.1 (± 11.5) years. Coronary angiography did not show any significant stenosis in LAD. OCT and flow wire analysis were performed in 14 and 12 patients, respectively. OCT analysis did show a normal three-layer vessel wall, without atherosclerotic plaque, images of plaques rupture, plaques erosion, or intraluminal thrombus. No patient had FFR ≤ 0.80, with a mean value of 0.96 ± 0.18 while 10 (83.3%) patients exhibited microvascular dysfunction with IMR of 33.8 ± 11.4.
Our study shows that LAD of TS patients may exhibit some degree of microvascular dysfunction in absence of atherosclerotic or vulnerable plaque. Future studies are needed to further determine the causes of this dysfunction.
IMAGING: FFR and Physiologic Lesion Assessment