Perfusion metabolism mismatch predicts short-term complications in Takotsubo syndrome
Authors: Sato T , Otaki Y , Suzuki Y , Kurihara M , Nanasato M , Iguchi N , Isobe M 
Published: October 2024

Abstract

Background
Takotsubo syndrome (TTS) is a transient cardiac condition triggered by sudden emotional or physical stress characterized by LV dysfunction in the absence of obstructive epicardial coronary artery disease. 123I-BMIPP, an iodinated fatty acid analogue, can identify impaired myocardial metabolic activity. With the use of dual SPECT protocol, reduced uptake of 123I-BMIPP compared to perfusion which is called perfusion-metabolic mismatch is observed in apical regions in TTS. The mismatch may indicate jeopardized but viable myocardium, reflecting transient ischemic damage or metabolically stunned myocardium. However, the association between the perfusion metabolism mismatch in TTS and its complications remains underexplored.

Purpose
Our study aimed to analyze the degree of perfusion metabolism mismatch at the acute phase in TTS and investigate its association with short-term complications.

Methods
This retrospective study conducted between 2012 and 2024 at a single center included 82 patients diagnosed with TTS. Patients underwent dual SPECT imaging using 99mTc or 201 Tl and 123I-BMIPP within two weeks of admission. We applied quantitative analysis using QGS/QPS software from Cedars-Sinai. Total perfusion deficit ("TPD") was calculated based on sex-matched normal limits providing the extent of perfusion abnormality. Meanwhile, perfusion-metabolism mismatch scores ("worsen") were determined by comparing the total BMIPP counts to the total counts of perfusion. We then assessed the correlation of these imaging findings with biomarkers, regional wall motion abnormalities, and the occurrence of short-term complications. Short-term complications included heart failure, left ventricular outflow (LVOT) obstruction, mitral regurgitation, cardiac arrhythmia, cardiogenic shock, left ventricle (LV) rupture, and cardiac death during the hospitalization period.

Results
All study patients exhibited wall motion abnormalities seen in apical segments. The count of myocardial segments with regional wall motion abnormality was correlated with both TPD (r=0.34, p=0.002) and perfusion metabolic mismatch score (r=0.40, p&lt;0.001). TPD had a moderate correlation coefficient with max CK-MB (r=0.44, p&lt;0.001) and troponin T (r=0.40, p&lt;0.001) levels. However, perfusion metabolic mismatch did not display correlations with max CK-MB (r=0.05, p=0.65), and Troponin T (r=0.12, p=0.28) levels. Among 82 patients, 37 patients experienced any short-term complications. Importantly, patients with short-term complications had elevated perfusion mismatch scores compared to those without short-term complications (14.0 [6.0-22.5] vs. 5.0 [3.0-10.0], p&lt;0.001). However, no significant difference was observed in TPD between the two groups (9.0 [4.5-20.0] vs. 7.0 [3.0-12.0], p=0.130).

Conclusions
Our research highlights a significant association between perfusion-metabolism mismatch and an increased risk for short-term complications in patients with Takotsubo syndrome.