Reversible impairment of coronary flow reserve in takotsubo cardiomyopathy: A myocardial PET study

Abstract

The acute phase of takotsubo cardiomyopathy is characterized by an inverse perfusion/metabolism mismatch with a reduction in CFR in the apical segments. However, the impairment of CFR and the reduction of metabolism in the apical segments recovered completely after 3 months.

Reversible Microvascular Dysfunction in Takotsubo Syndrome Shown Using Index of Microcirculatory Resistance

“…Reversibility of MVD in this syndrome has been demonstrated non-invasively on Doppler transthoracic echocardiography 7 and positron emission tomography, 8 and invasively with intracoronary Doppler wire 9 in previous studies using CFR. IMR, however, is considered more useful to detect MVD because of the independence of epicardial stenosis and hemodynamic status, 10,11 but only 2 cases of MVD in takotsubo syndrome have been reported using IMR in the acute phase.…”

Microvascular Dysfunction in Takotsubo Cardiomyopathy

“…Invasive studies (using TIMI frame counts, myocardial perfusion grading, intracoronary Doppler evaluation of vasomotor function, coronary flow reserve and thermodilution method to assess index of microvascular resistance) and noninvasive studies (using doppler echocardiography, myocardial contrast echocardiography, SPECT/PET metabolism/ perfusion and Cardiac MRI) have all demonstrated coronary microvascular dysfunction in the acute phase of takotsubo cardiomyopathy 5,7,[12][13][14][15][17][18][19][20][22][23][24][25][26][27][28]33 Of significance, all of these microvascular abnormalities demonstrated by both invasive and noninvasive testing usually are transient and reversible, with follow up testing indicating normalization of microvascular function, in parallel with recovery of LV function. The precise mechanism of this transient coronary microvascular dysfunction, although not completely understood, could involve adrenoreceptor overstimulation/sympathetic hyperactivity, resulting from a catecholamine surge secondary to physical or emotional stress and differences in the type and density of adrenoreceptors in the cardiac apex versus the base might partly explain the proclivity of transient apical dysfunction in TC.…”

“…3 In a study of 3 patients with TC, Feola et al evaluated myocardial perfusion and myocardial blood flow using PET imaging. 26 All 3 patients underwent coronary angiography at admission which ruled out significant coronary stenosis. PET perfusion imaging using N13 ammonia at rest and during pharmacologic stress with adenosine and metabolic imaging using FDG was done within 3 days of presentation and again at 3 months of follow up.…”

“…The LV dysfunction, impaired glucose uptake and reduced CFR demonstrated reversibility at 3 months, likely due to resolution of microvascular dysfunction. 26 In another case report by Feola of a 65 year old woman with TC, PET imaging was performed at day 5 and day 6 of presentation with N13 ammonia as perfusion tracer and FDG for metabolic imaging. 27 There was similar evidence of inverse perfusion/metabolism mismatch, with severe metabolic impairment at the apex, but preserved perfusion.…”

Under the hood of the stunned takotsubo heart

“…Using 13 N-NH3 and hyperinsulinemic-euglycemic clamp prepped 18 F-FDG PET, Feola and colleagues showed reductions in both coronary flow reserve and glucose metabolism in the apical segments during the acute phase in 3 TC patients that recovered completely after 3 months. 25 During the acute phase, FDG uptake was severely reduced in the apical and mid-ventricular segments in all 3 patients, with only modest reductions in stress perfusion that normalized at rest (described as an inverse-mismatch of flow/metabolism). 25 The authors suggested a transient metabolic disorder at the cellular level from a microcirculation disturbance as the potential explanation of their findings.…”