DISCUSSION
Life expectancy is increasing steadily in many countries and
consequently presents a higher incidence of cardiovascular diseases,
including ATAAD,13, 14 which remains a potentially
lethal clinical presentation as emergency surgery is still a challenging
procedure for elderly patients. It has been reported that surgical risks
are increased in the elderly and old age is a negative prognostic factor
of early mortality after emergency surgery for ATAAD.2, 3, 15, 16 However, surgical outcomes for ATAAD have
been improving in Japan 17 as well as in the rest of
the world18, with several studies reporting good
results from the surgical repair of ATAAD in elderly
patients.4, 13 Surgical outcomes in elderly patients
with ATAAD may improve in this decade. Postoperative physical activities
may be strongly associated with quality of life, mental health, and
functional capacity in elderly patients with ATAAD.8It is reported that walking difficulty is an important risk factor for
mortality and morbidity in patients after elective cardiac
surgery.6, 19 However, there are few studies that
assess physical activities or rehabilitation outcomes in elderly
patients after surgery for ATAAD.
This study demonstrated that: 1) there were no significant differences
in short-term and long-term mortality and major postoperative
complications between patients undergoing surgical repair for ATAAD in
the elderly group and in the control group; 2) during rehabilitation, it
took significantly longer for elderly patients to walk 100 or 200 m and
to require speech and swallowing therapy postoperatively for dysphagia;
3) the AUC of the 200-m walk after surgery as a prognostic indicator for
late mortality was 0.878, with a highest accuracy at 30 days
(sensitivity = 83.3%, specificity = 91.8%); 4) intriguingly,
postoperative walking difficulty was an independent risk factor for late
mortality in patients regaining ambulatory autonomy at discharge as well
as in all cohorts.
It is still unclear what specific types and intensities of
rehabilitation may be postoperatively safe and beneficial for patients
with ATAAD. In this study, cardiopulmonary exercise testing or invasive
walking tests were not performed to assess physical activities because
the safety and efficacy of these tests have not yet been fully
established in patients with postoperative residual aortic dissection
for ATAAD.7, 20 However, we assessed the duration for
the patients to walk 100 or 200 m postoperatively, which is less
invasive and helps to assess postoperative physical activity resumption
with ease compared with cardiopulmonary exercise testing or other walk
tests.
Corone et al reported 33 French patients with type I DeBakey aortic
dissection (mean age, 55.1 years) who underwent cardiac rehabilitation
soon after surgical repair.21 They reported that
noncontact aerobic activity with moderate intensity is likely safe and
effective for patients with surgical repair for ATAAD. In this study,
our rehabilitation program was based on walking exercise. During
rehabilitation, acute elevations in BP may transiently increase the risk
of recurrent aortic dissection or rupture after surgical repair for
ATAAD,22, 23 because a postdissection aorta is almost
invariably dilated and may have increased associated wall stress
compared with a nondilated aorta.24 During
rehabilitation in our study, sBP was strictly controlled between
100–130 mmHg with antihypertensive drugs without any aortic event,
which may support the safety profile of our rehabilitation program.
Elderly patients required fewer antihypertensive drugs to control blood
pressure during the rehabilitation. Because BMI in the elderly group was
significantly lower than the control group, small body size and older
age in the elderly group may affect pharmacological metabolism.
The most obvious limitations of this study were its retrospective
nature, small number of participants, and single-center design, which
are potential sources of bias. In addition, although the majority of
patients showed preoperative independence in activities of daily living
in this study, patients with impaired physical activity may not have
been transferred to our hospital because the family or patients did not
want surgical treatment or because they were assessed as inoperable by
former doctors. Furthermore, the mean follow-up period in the elderly
group was comparatively short (median 42.5 [18.8–75.8] months;
range 1–125 months), although we did not find significant differences
in long-term follow up between the elderly group and the control group.
Further studies with a larger number of patients, longer observation
time, and greater emphasis on hemodynamic and biomechanical parameters
should be performed to evaluate physical activities and surgical
outcomes in elderly patients with ATAAD.