3 DISCUSSION
TTC is an acute reversible myocardial injury first reported by Sato et
al. in 1990. The term “takotsubo” means an octopus fishing pot in
Japanese that has a round bottom and a narrow neck, and it is similar to
the shape of the heart in TTC. TTC is triggered by emotional (negative
and positive) or physical stress, including
asthma exacerbation. Symptoms
similar to those of myocardial infarction have been observed in patients
with TTC, without coronary artery stenosis [3,8,9].
The pathophysiology of stress cardiomyopathy is unclear and may involve
several mechanisms. One pathway involves high circulating catecholamines
released by the sympathetic nerves under stress, including respiratory
diseases. Sato et al. showed that microvascular dysfunction and coronary
artery spasms cause TTC.
As most patients with TTC are postmenopausal women, estrogen deprivation
has been proposed as a cause in several hypotheses [20], whereas
some studies have reported abnormalities in the central autonomic
nervous system [10].
Although TTC has a good prognosis, patients with TTC sometimes develop
heart failure, arrhythmia, systemic embolism, cardiogenic shock, and
cardiac rupture, which might be fatal. Underlying diseases triggering
TTC increase mortality (12.2% vs. 1.1% in patients without preexisting
diseases) [6]. Our patient did not have cardiac complications;
however, adequate treatment for asthma was required.
Dyspnea is a common symptom in respiratory illnesses and TTC; therefore,
electrocardiography and echocardiography should be performed before the
use of SABAs or adrenaline.
Infection with SARS-CoV-2, a novel virus that was first reported in
Wuhan, China in 2019, might trigger asthma flare-up; however, the
SARS-CoV-2 polymerase chain reaction test of the patient was negative,
indicating that she was not infected with SARS-CoV-2. COVID-19
aggravates many diseases; therefore, vaccines have been developed and
implemented rapidly worldwide to reduce the risk of progression and
death. mRNA-based COVID-19 vaccines are effective and safe. Nonetheless,
adverse events associated with the vaccines are not completely
understood. Almost all COVID-19 vaccines used in Japan are mRNA-based.
TTC has been reportedly triggered by mRNA-based COVID-19 vaccines
[11,12,13] or the influenza vaccine [12,14]. However, our
patient had status asthmaticus, and the vaccination did not seem
directly of TTC, despite her symptoms being common to both diseases.
Colaneri et al. reported a case of asthma exacerbation triggered by an
mRNA-based COVID-19 vaccine [1]. mRNA-based vaccines promote
secretion of type I interferons and that increased interferon-I
production is associated with asthma exacerbation [15,16]. Nappi et
al. reported a case in which two doses of the adenovirus-vectored
vaccine ChAdOx1 (Astra Zeneca) progressively worsened asthma and a
subsequent dose of the COVID-19 vaccine mRNA-1273 (Moderna) triggered
eosinophilic granulomatosis with polyangiitis [17]. Regardless of
the type of vaccine, COVID-19 vaccination itself may exacerbate asthma.
Hence, we concluded that the mRNA-based vaccine enhanced asthma
exacerbation and TTC onset in our patient. However, our study was
limited because the relationship between asthma exacerbation and
mRNA-based COVID-19 vaccines is currently difficult to demonstrate
directly. Thus, more reports and further studies are required.
Between February 17, 2021, and July 25, 2021, 74,137,348 patients
received the BNT162b2 vaccine in Japan. Among these, 219 (0.0003%)
cases of asthma attacks were reported to the Japanese Ministry of
Health, Labour, and Welfare, which indicates a low incidence [18].
Pfaar et al. reported that patients taking biologicals for asthma do not
have an increased risk of allergic reactions following COVID-19
vaccination [19].