2.3 The vicious circle: stroke–heart syndrome
Due to the extremely wide prevalence of COVID-19, the management of
stroke cannot be ignored. The presence of a true relationship between
COVID-19 and stroke remained to be determined. Although the number of
stroke hospitalizations had declined, the evidence was available that
COVID-19 infection itself may cause a stroke. It was worth noting that,
without excluding the possibility of the virus directly invading the
nervous system, heart injury seemed to be an important feature of this
disease. The impairment of cardiac function occurs in 20-30% of
hospitalized COVID-19 patients [15]. In a pooled analysis, the
cerebrovascular disease was found to be associated with a 2.5-fold
increase in the severity of COVID-19 [16]. In addition, medical
records from three hospitals in Wuhan indicated that 5.9% of the
patients had COVID-19 infection complicated with stroke, and these
patients were older, with more CVD complications, and more severe
pneumonia. Stroke mechanisms in these cases might include
hypercoagulable state caused by critical illness and cardiogenic
embolism caused by virus-related heart damage [17]. The expression
of ACE2 on vascular smooth muscle cells may also be a potential target
for SARS-CoV-2 infection. The pathological analysis of COVID-19 patients
documented the presence of microvascular inflammation and
microthrombosis in the lungs and other affected organs [18].
Importantly, many incidences of sudden death and severe non-fatal
cardiac events after the stroke may result from the interaction between
cardiovascular and nervous systems [19]. Therefore, considering the
possibility that COVID-19 may promote cardiac and microvascular
thrombosis at various levels, the incidence of a stroke may increase
with the thrombus entering the brain in COVID-19 patients. Thus, the
vicious cycle in which the heart function is affected by brain damage
should be considered by clinicians.