Acute coronary syndromes occurring while driving: frequency and patient characteristics
Inamasu et al. Environmental Health and Preventive Medicine
Acute coronary syndromes occurring while driving: frequency and patient characteristics
Joji Inamasu 0
Satoru Miyatake 0
Takashi Yagi 1
Shigetaka Noma 1
0 Department of Emergency Medicine, Saiseikai Utsunomiya Hospital , 1-98 Takebayashi, Utsunomiya 321-0974 , Japan
1 Department of Cardiology, Saiseikai Utsunomiya Hospital , Utsunomiya , Japan
Background: Acute coronary syndrome (ACS) may occur during any human activity, including driving. The objectives of this study were to report the frequency of ACS occurring while driving, clarify patient characteristics, and analyze the behavioral patterns of drivers who sustained ACS. Methods: A single-center, retrospective observational study was conducted using prospectively acquired data. Among 1605 ACS patients admitted between January 2011 and December 2016, 65 (60 men/5 women) patients who sustained ACS while driving were identified. Clinical variables were compared between these 65 patients and 1540 patients who sustained ACS while performing other activities. Furthermore, multivariable regression analysis was performed to identify variables associated with ACS. Results: The frequency of ACS occurring while driving was 4.0% (65/1605). Compared with patients who sustained ACS while performing other activities, those who sustained ACS while driving were significantly younger (66.2 ± 13.0 vs. 57.5 ± 12.2 years, p < 0.001) and more likely to smoke (34.2 vs. 60.0%, p < 0.001). Multivariable regression analysis showed that age (OR 0.961; 95% CI 0.940-0.982) and current smoking (OR 1.978; 95% CI 1.145-3.417) were associated with ACS. While 55 drivers (85%) who remained conscious after ACS could seek medical attention without causing accidents, the other 10 (15%) who sustained cardiac arrest caused accidents. Conclusions: The association between current smoking and ACS occurring while driving suggests that smoking cessation is advised for smokers who drive from the standpoint of driving safety. We expect that prospective studies be conducted to verify our findings and identify individuals at risk for ACS while driving.
Acute coronary syndrome; Driving; Risk factors; Smoking
Acute coronary syndrome (ACS) may occur during any
human activity, including driving [
]. The objectives
of this study were to report the frequency and patient
characteristics of ACS occurring while driving. An effort
was made to identify variables associated with ACS
occurring while driving. Furthermore, the behavioral patterns of
afflicted drivers were analyzed to clarify relationship
between ACS and automobile accidents.
This was a single-center, retrospective observational
study conducted using prospectively acquired data.
The study protocol was approved by our institution’s
ethics committee. ACS was defined as the presence
of either ST-segment elevation myocardial infarction
(STEMI), non-ST-segment elevation myocardial
infarction, or unstable angina pectoris [
]. ACS was
generally treated according to the recent guidelines
]. After arrival in the emergency department (ED),
the temporal sequence of resuscitative events was
recorded on an integrated clinical database CAP-2000
(Nihon Kohden, Tokyo, Japan) by ED residents.
Detailed information on when, where, and how the
patients’ symptoms developed was obtained from
patients, surrogates, or paramedics. They were also
asked about activities performed immediately before
symptom onset. We modified the classification of
daily activities by Hayashi et al., in which the
activities were classified into eight categories (sleeping,
resting, eating, walking, hard working, bathing/toilet,
driving, and other activities) [
Unless contraindicated, patients suspected of ACS
routinely underwent contrast-enhanced whole-body
computed tomography to rule out aortic dissection.
Patients diagnosed with ACS were brought to a
catheter lab for possible percutaneous coronary
intervention (PCI). We used a dataset of 1605 newly
diagnosed ACS patients, aged ≥ 18 years, who were
admitted to our institution between January 2011 and
December 2016. Patients who drove to our institution
with symptoms that had occurred while performing
other activities as well as those with stable angina
pectoris who noticed chest pain while driving were
excluded from analysis. Geriatric patients who were
transferred from nursing care facilities were also
Fisher’s exact test was used to compare differences in
categorical variables, and Student’s t test was used to
compare differences in numerical variables. Numerical
data are expressed as the mean ± SD, and p < 0.05 was
considered statistically significant. Multivariable
logistic regression analysis was performed using JMP
software (SAS Institute, Cary, NC, USA) to identify
variables associated with ACS occurring while driving
]. The variables included age, sex, proportion of
STEMI, and cardiovascular risk factors (hypertension,
past history of ischemic heart diseases, dyslipidemia,
diabetes mellitus, and current smoking). Drinking was
not included in the risk factors because making a
distinction between habitual and social drinkers was
difficult on our database.
The 1605 ACS patients consisted of 1272 men and 333
women with mean age of 65.8 ± 13.0 years. Among
these, 65 (60 men/5 women) sustained ACS while
driving. The activities at the time of symptom onset in the
other 1540 patients were as follows: sleeping, 284;
resting, 361; eating, 89; walking, 227; hard working, 230;
bathing/toilet, 91; and other activities, 347. As a result,
the frequency of driving among all daily activities at the
time of symptom onset was 4.0%. There were 7
professional drivers (10.8%). While 55 drivers presented with
acute chest and/or back pain, the other 10 drivers
presented with cardiac arrest.
Demographic variables were compared between the 65
patients who sustained ACS while driving and the 1540
patients who sustained ACS while performing other
activities. The patients who sustained ACS while driving
were significantly younger than those who sustained
ACS while performing other activities (57.5 ± 12.2 vs.
66.2 ± 13.0 years, p < 0.001) (Table 1). The former group
also exhibited significant higher body mass index (BMI)
(25.5 ± 5.8 vs. 23.8 ± 3.9 kg/m2, p < 0.001). Regarding the
risk factors, the frequency of current smoking was
significantly higher in the former (60.0 vs. 34.2%, p < 0.001).
However, the frequencies of other risk factors did not
Regarding the relationship between gender and
smoking status, the male group showed significantly
higher frequency of current smoking than the female
counterpart (520/1272 vs. 46/333, p < 0.001).
Subsequently, demographics including smoking status were
compared between 60 male patients who sustained ACS
while driving and 1212 male patients who sustained ACS
while doing other activities (Additional file 1: Table S1).
While the frequency of current smoking was
significantly higher in the former (63.3 vs. 39.7%, p < 0.001),
there were no significant intergroup differences in
Multivariable logistic regression analysis
Multivariable regression analysis was conducted to
identify variables associated with ACS occurring while
driving, and the results are summarized in Table 2. Age
(OR 0.961; 95% CI 0.940–0.982; p < 0.001) and current
smoking (OR 1.978; 95% CI 1.145–3.417; p = 0.015)
were found to be associated with ACS occurring while
driving (Table 2).
Response of drivers to ACS
The response of the 65 drivers shortly after ACS is
illustrated in Fig. 1. While 10 drivers became
comatose and were unable to keep driving because of
cardiac arrest, the other 55 (85%) managed to keep
driving after sustaining ACS. Among these, 34
patients (62%) could not complete their intended
activities because of symptoms; more precisely, they
either drove directly to a local hospital or pulled
over and called an ambulance for help. The other 21
(38%) could complete their intended activities, i.e.,
driving to their destinations, and sought medical
attention afterwards. Of the 1540 patients who
sustained ACS while doing other activities, 1248 were
conscious at the time of onset. While 655 patients
(52%) could not complete their intended activities
because of symptoms, the other 593 (48%) could
complete their intended activities and sought medical
attention afterwards. Regarding the behavioral
patterns, i.e., whether patients’ activities were
interrupted by symptoms or not, there was no significant
intergroup difference (p = 0.21).
None of the 55 drivers who remained conscious after
ACS caused automobile accidents. The other 10 drivers
(15%) caused automobile accidents after sustaining
ACS-induced cardiac arrest. Seven of 10 patients with
cardiac arrest achieved return of spontaneous circulation
after resuscitation and underwent PCI (Fig. 1).
Circadian variation and ACS occurring while driving
We divided a 24-h day into four time zones (6–12,
12–18, 18–0, and 0–6 h) and investigated whether
ACS was more likely to occur in a specific time zone.
The number of drivers who sustained ACS in each
quartile was 37, 20, 6, and 2, respectively (Fig. 2).
Fifty-four percent of ACS while driving had occurred
in the first quartile.
Acute cardiovascular events occurring while driving
have been studied relatively frequently [
most of those studies were conducted by either forensic
scientists or crash scene investigators, and only drivers
whose cardiovascular events led to loss of
consciousness and subsequent automobile accidents have been
]. In this context, the present study was
unique as it focused on all patients who sustained ACS
while driving. The frequency of ACS occurring while
driving in our cohort, consisting of adults who led
independent lives, was 4.0%. There was a marked circadian
variation in the frequency of ACS occurring while
driving, with more than 50% of drivers experiencing
symptoms in the morning (Fig. 2). While this may
have been simply because traffic volume was heavy
with commuters in the morning, it may have also
reflected the fact that ACS in itself is most likely to
occur in the morning [
It is likely that ACS occurred while driving merely
by chance in the great majority of patients. In other
words, causality between driving and ACS is mostly
questionable. Nevertheless, demographic comparison
(Table 1) as well as multivariable regression analysis
(Table 2) suggests that current smoking may be a risk
factor for ACS occurring while driving. Smoking
promotes hypercoagulability via the action of carbon
]. In addition, drivers sit in a confined
space in the same posture for hours, and
uninterrupted sitting while driving per se may be associated
with hypercoagulability [
]. Furthermore, drivers
may become dehydrated after driving for hours
without drinking water. Higher BMI in the afflicted
drivers (Table 1) also suggests that underlying obesity
may have some role in the causation of ACS
occurring while driving. Taken together, combination of
these adverse factors may result in thrombosis of the
coronary arteries and ACS. In addition to current
smoking, age was correlated with ACS: younger adult
drivers might be more likely to sustain ACS than
their elderly counterparts (Table 2). However,
interpretation of this finding requires caution, because
driving, smoking habit, and aging process is
complicatedly intertwined: the elderly generally drives less
frequently and for shorter distances than the younger
population, and the smoking rate drops as age
]. Male sex was not associated with
ACS (Table 2), and it remains unclear whether gender
difference influences the likelihood of developing ACS
while driving. Nevertheless, male smokers may be at
increased risk for ACS while driving (Additional file 1:
Table S1). The fact that women drive less often and
cease driving earlier than men should also be
considered in interpreting the marked male preponderance
of 92% (Table 1) [
]. Based on these findings,
smoking cessation is advised for drivers who smoke from a
standpoint of driving safety. A recent study showing
the efficacy of smoking ban in the reduction of ACS
suggests that regulations to limit the use of cigarette
while driving may be worth consideration [
Regarding the relationship between ACS and
automobile accidents, the majority of drivers who
sustained ACS kept driving without accidents and
managed to reach medical facilities (Fig. 1). By
contrast, all 10 patients who sustained cardiac arrest while
driving caused automobile accidents. It is likely that
loss of consciousness after cardiac arrest resulted in
loss of control of vehicles and accidents. We expect
that devices to enable earlier detection of driver
deterioration are installed in future vehicles to prevent
or reduce automobile accidents.
There are limitations to the present study. First,
sample number was relatively small due to the
single-center retrospective study design. Moreover,
this was not a population-based study, and the
incidence of ACS occurring while driving remains
unknown. Second, the information on the temporal
relationship between driving and onset of symptoms,
mostly acute chest pain, was mostly obtained from
the patients themselves, indicating the possibility of
a recall bias. Finally, despite the apparent adverse
effects of smoking, information on the quantity of
cigarettes consumed by drivers was not always
collectible. It was also unclear how many drivers
sustained ACS while they were smoking in their
vehicles. Despite these limitations, the present study
is probably the first to document the frequency and
patient characteristics of ACS occurring while
driving. As the elderly population grows rapidly, the
incidence of ACS occurring while driving may also
increase worldwide. Prospective multicenter studies
should be conducted to identify individuals at risk
for ACS while driving.
Additional file 1: Table S1. Comparison of variables between male
patients who sustained ACS while driving and male patients who sustained
ACS while performing other activities. (DOC 32 kb)
ACS: Acute coronary syndrome; BMI: Body mass index; CI: Confidence
interval; ED: Emergency department; OR: Odds ratio; PCI: Percutaneous
coronary intervention; SD: Standard deviation; STEMI: ST-segment elevation
The corresponding author (JI) received research grants from (1) the General
Insurance Association of Japan and (2) Fujita Health University Center for
Research Promotion and Support (grant no. 13-010). None of the remaining
authors received any research grants for this study.
Availability of data and materials
Data sharing is not applicable to this article as no datasets were generated
or analyzed during the current study.
JI conceived the study design and carried out data analysis and manuscript
preparation; SM carried out data acquisition and data analysis (including
statistics); TM carried out data acquisition and data analysis; SN was
responsible for supervision of the study proposal to the ethics committee
and manuscript. All authors read and approved the final manuscript.
Ethics approval and consent to participate
The study protocol was approved by the Saiseikai Utsunomiya Hospital
Ethics Committee (consisting of five members). The study was given an ID
Number of 2016-34. The committee decided that consent to participate from
each patient was waived for this study.
Consent for publication
The authors declare that they have no competing interests.
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