The underlying mechanisms of microvascular dysfunction in Takotsubo cardiomyopathy remain incompletely understood. As CD34+ cells are essential to coronary microvascular homeostasis we will investigate the potential association between CD34+ cell count and changes in left ventricular function in patients with Takotsubo cardiomyopathy at baseline and 6-month follow-up.
Takotsubo syndrome presents with a transient non-ischemic acute heart failure and relatively fast recovery of myocardial contractility. This medical condition is often precipitated by a previous trigger, such as physical or emotional stress. However, in approximately one-third of Takotsubo patients, the trigger remains unidentified. In terms of acute clinical presentation, Takotsubo patients with and without acute coronary syndrome-related symptoms have been recognized. Early recognition of the latter group is challenging due to the lack of clear indication for transthoracic echocardiography and coronary angiography with left ventriculography in this patient cohort, representing the gold standard in diagnostics of Takotsubo patients. Therefore, the prevalence of Takotsubo patients without acute coronary syndrome-related symptoms appears to be underestimated. In addition, novel data reveal that both short- and long-term prognoses in Takotsubo patients are comparable to the prognosis in acute coronary syndrome patients. Furthermore, chronic heart failure has been recognized in a subgroup of Takotsubo patients. To sum up, Takotsubo syndrome represents a heterogeneous medical condition, with a potential for adverse outcomes. This calls for new approaches to the diagnostics and treatment of this patient population. Coronary microvascular dysfunction has been proposed as a crucial pathophysiological mechanism underlying Takotsubo pathogenesis, including the left ventricular dysfunction at acute episode and the degree/rate of left ventricular contractility improvement. As CD34+ cells are essential to coronary microvascular homeostasis we speculated on potential association between CD34+ cell count and changes in left ventricular function in patients with Takotsubo cardiomyopathy at baseline and 6-month follow-up. In this single-center prospective pilot cohort study we included 34 consecutive patients with Takotsubo cardiomyopathy treated at our center between September 2021 and January 2026. Patients with a history of malignancy and concurrent acute coronary syndrome-mimicking conditions (myocardial infarction, myocarditis, etc) were not considered for this analysis. Takotsubo cardiomyopathy diagnosis was established per InterTac Registry criteria. Patients were enrolled within 24h of admission and underwent comprehensive clinical examination, blood biochemical and hematological analysis, and echocardiography at baseline and 6-month follow-up. Additionally, we expect at least half of the enrolled patients to complete cardiac MRI scan at baseline and 6-month follow-up. CD34+ cell count was measured using Beckman-Coulter Navios EX flow cytometry with standard antibodies according to ISAGE protocol. The study results might enhance undertsanding of the pathophgysiological mechanism underlying structural and functional myocardial recovery among Takotsubo patients. Also, the study outcomes might provide crucial context for justifying further research work on investigating potential therapeutic effects of CD34+ cells on myocardial contractility recovery among Takotsubo patients.
Study Type
OBSERVATIONAL
Enrollment
40
Advanced Heart Failure and Transplantation Program, Department of Cardiology, UMC Ljubljana, Slovenia
Ljubljana, Ljubljana, Slovenia
RECRUITINGRecovery of left ventricular systolic function assessed by change in left ventricular ejection fraction (LVEF)
Change in LVEF (%), measured by transthoracic echocardiography using Biplane Simpson's method.
Time frame: From enrollment to the end of observational period at 6-month follow-up.
Improvement in myocardial contractility and deformation assesed by change in left ventricular global longitudinal strain (LV GLS)
Change in LV GLS (%), measured by transthoracic echocardiography using speckle-tracking method.
Time frame: From enrollment to the end of observational period at 6-month follow-up.
Reduction in left ventricular filling pressure assessed by change in early mitral inflow velocity (E-wave) and the average of the septal and lateral early diastolic mitral annular velocities ratio (E/e' average)
Change in E/e' average, calculated from transthoracic echocardiography by dividing the peak early mitral inflow velocity (E-wave) by the average of the septal and lateral early diastolic mitral annular velocities (e') obtained via tissue doppler imaging.
Time frame: From enrollment to the end of observational period at 6-month follow-up.
Recovery of impaired myocardial relaxation assessed by change in peak early mitral inflow velocity and peak atrial contraction wave velocity ratio (E/A ratio)
Change in E/A ratio, calculated from transthoracic echocardiography by dividing the peak early mitral inflow velocity (E-wave) by the peak atrial contraction velocity (A-wave), both measured via pulsed-wave Doppler in the apical four-chamber view.
Time frame: From enrollment to the end of observational period at 6-month follow-up.
Reduction in pulmonary artery systolic pressure assessed by change in tricuspid regurgitation maximum gradient (TR max gradient)
Change in TR max gradient (mmHg), measured using transthoracic echocardiography by applying continuous wave (CW) doppler to the TR jet to determine the peak velocity, then applying the modified Bernoulli equation.
Time frame: From enrollment to the end of observational period at 6-month follow-up.
Reduction in left ventricular size assessed by left ventricular end-diastolic volume index (LVEDVi)
Change in LVEDVi (mL/m2), calculated from transthoracic echocardiography using Biplane Simpson's method and indexed to body surface area.
Time frame: From enrollment to the end of observational period at 6-month follow-up.
Reduction in left ventricular wall thickness assessed by posterior (inferolateral) wall diameter (PWd) and interventricular septal diameter (IVSd)
Change in PWd (mm) and IVSd (mm), assessed by transthoracic echocardiography using parasternal long-axis view.
Time frame: From enrollment to the end of observational period at 6-month follow-up.
Improvement in right ventricular systolic function assessed by tricuspid annular plane systolic excursion (TAPSE)
Change in TAPSE (mm), assessed by transthoracic echocardiography and measured in the apical 4-chamber view using M-mode placed at the lateral tricuspid annulus.
Time frame: From enrollment to the end of observational period at 6-month follow-up.
Reduction in the extent of myocardial oedema assessed by cardiac magnetic resonance imaging
Change in the extent of myocardial oedema, assessed by cardiac magnetic resonance imaging scan using T2-weighted imaging and T2-mapping (T2 relaxation times in miliseconds).
Time frame: Baseline and 6-month follow-up.
Remnants of cardiac fibrosis assessed by the extent of late gadolinium enhancement (LGE)
Change in the extent of myocardial LGE (% of left ventricular mass), quantified by cardiac magnetic resonance (CMR).
Time frame: Baseline, 6-month follow-up.
Recovery of coronary microvascular dysfunction assessed by change in angiogenesis-related biomarkers
Change in angiogenesis-related biomarker panel composite score, measured using a Luminex multiplex immunoassay.
Time frame: From enrollment to the end of observational period at 6-month follow-up.
Reduction in cardiac congestion assessed by change in serum levels of natriuretic peptides (NT-proBNP)
Change in serum levels of NT-proBNP (ng/L), measured in blood sample by serum biochemical analysis.
Time frame: From enrollment to the end of observational period at 6-month follow-up.
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