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No differences in rest myocardial blood flow in stunned and hibernating myocardium: insights into the pathophysiology of ischemic cardiomyopathy


Benz, Dominik C; von Dahlen, Anita P; Huang, Wenjie; Messerli, Michael; von Felten, Elia; Benetos, Georgios; Giannopoulos, Andreas A; Fuchs, Tobias A; Gräni, Christoph; Gebhard, Catherine; Pazhenkottil, Aju P; Gaemperli, Oliver; Kaufmann, Philipp A; Buechel, Ronny R (2019). No differences in rest myocardial blood flow in stunned and hibernating myocardium: insights into the pathophysiology of ischemic cardiomyopathy. European Journal of Nuclear Medicine and Molecular Imaging, 46(11):2322-2328.

Abstract

PURPOSE

The human pathophysiology of stunned, hibernating and scarred myocardium in ischemic cardiomyopathy is a subject of controversy. While the "smart heart" theory postulates that reduced myocardial blood flow (MBF) at rest is responsible for myocytes switching to a state of hibernation, other theories suggest that a reduced myocardial flow reserve (MFR) may be the cause.

METHODS

We included 110 patients with ischemic cardiomyopathy. Based on quantitative myocardial perfusion assessment and viability imaging with $^{13}$N-NH3 and $^{18}$F-FDG positron emission tomography, respectively, as well as wall motion assessment from echocardiography, myocardial tissue was characterized as remote (i.e., normal myocardium), stunned (i.e., dysfunctional but viable myocardium with normal rest perfusion), hibernating (i.e., dysfunctional but viable myocardium with impaired rest perfusion), or scarred myocardium (i.e., non-viable myocardium).

RESULTS

Compared to remote myocardium, dysfunctional but viable myocardium (including stunned and hibernating) had reduced rest MBF (0.89 mL/min/g vs. 0.79 and 0.76 mL/min/g, respectively; p < 0.001) and MFR (1.53 vs. 1.27 and 1.17; p < 0.001). Between stunned and hibernating myocardium, however, rest MBF and MFR did not differ (p = 0.40). In scarred myocardium, rest MBF was lowest (0.66 mL/min/g; p < 0.001) but, in contrast to the other myocardial states, k2 (i.e., tracer washout) was increased (0.199/min vs. 0.178/min to 0.181/min; all p < 0.05 in pairwise comparison).

CONCLUSIONS

In patients with ischemic cardiomyopathy, impaired MFR is associated with stunning and hibernation. These states of dysfunctional but viable myocardium have lower rest MBF compared to remote myocardium. At the end of the continuum, rest MBF is lowest in scar tissue and linked to increased rate of tracer washout.

Abstract

PURPOSE

The human pathophysiology of stunned, hibernating and scarred myocardium in ischemic cardiomyopathy is a subject of controversy. While the "smart heart" theory postulates that reduced myocardial blood flow (MBF) at rest is responsible for myocytes switching to a state of hibernation, other theories suggest that a reduced myocardial flow reserve (MFR) may be the cause.

METHODS

We included 110 patients with ischemic cardiomyopathy. Based on quantitative myocardial perfusion assessment and viability imaging with $^{13}$N-NH3 and $^{18}$F-FDG positron emission tomography, respectively, as well as wall motion assessment from echocardiography, myocardial tissue was characterized as remote (i.e., normal myocardium), stunned (i.e., dysfunctional but viable myocardium with normal rest perfusion), hibernating (i.e., dysfunctional but viable myocardium with impaired rest perfusion), or scarred myocardium (i.e., non-viable myocardium).

RESULTS

Compared to remote myocardium, dysfunctional but viable myocardium (including stunned and hibernating) had reduced rest MBF (0.89 mL/min/g vs. 0.79 and 0.76 mL/min/g, respectively; p < 0.001) and MFR (1.53 vs. 1.27 and 1.17; p < 0.001). Between stunned and hibernating myocardium, however, rest MBF and MFR did not differ (p = 0.40). In scarred myocardium, rest MBF was lowest (0.66 mL/min/g; p < 0.001) but, in contrast to the other myocardial states, k2 (i.e., tracer washout) was increased (0.199/min vs. 0.178/min to 0.181/min; all p < 0.05 in pairwise comparison).

CONCLUSIONS

In patients with ischemic cardiomyopathy, impaired MFR is associated with stunning and hibernation. These states of dysfunctional but viable myocardium have lower rest MBF compared to remote myocardium. At the end of the continuum, rest MBF is lowest in scar tissue and linked to increased rate of tracer washout.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Klinik für Konsiliarpsychiatrie und Psychosomatik
04 Faculty of Medicine > University Hospital Zurich > Clinic for Nuclear Medicine
Dewey Decimal Classification:610 Medicine & health
Language:English
Date:October 2019
Deposited On:07 Feb 2020 13:27
Last Modified:19 Feb 2020 08:56
Publisher:Springer
ISSN:1619-7070
OA Status:Closed
Publisher DOI:https://doi.org/10.1007/s00259-019-04440-2
PubMed ID:31359109

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