Discussion
The present study investigated the long-term prognostic value of
malnutrition assessed by the CONUT score in CAS patients and the results
indicated a higher prevalence of all-cause death and stroke in
malnourished patients compared to patients with normal nutrition.
The CONUT score was first described by Ignacio de Ulı´barri et al as an
objective parameter reflecting malnutrition in hospitalized patients
(13). In recent studies, the association of the CONUT score with
clinical poor outcomes has been demonstrated in various cardiovascular
diseases. Takahashi et al. reported that high CONUT score was associated
with adverse outcomes in patients with ACS and also showed its
prognostic value in ACS patients (15). Nochioka et al. showed that
malnutrition assessed by the CONUT score was associated with adverse
cardiac events in patients with chronic heart failure (17). Kunimura et
al. demonstrated that the combined use of BMI and CONUT score in stable
CAD was associated with MACE (18). In some other studies, the CONUT
score was shown to be an independent strong predictor of adverse
cardiovascular events and foot events in PAD patients (19).
Additionally, it was also reported to be associated with increased
prevalence of all-cause death in patients with ST elevation myocardial
infarction (STEMI) (20).
To date, numerous nutritional indicators such as serum albumin, total
cholesterol, Mini Nutritional Assessment (MNA), Subjective Global
Assessment (SGA), and Geriatric Nutritional Risk Index (GNRI) have been
reported (21-23). Of these, MNA and SGA are dependent on the physician’s
subjective observations. Nevertheless, an evaluation performed with only
one nutritional indicator may be affected by various factors and may not
provide sufficient information. Therefore, in this study, we used PNI in
addition to the CONUT score. PNI, which is calculated on serum albumin
level and total lymphocyte count, is an objective nutritional indicator
reflecting the immune-nutritional status of individuals. Decreased
albumin and lymphocyte response in acute diseases reflect poor
immune-nutritional status. On the other hand, PNI is mainly used as a
parameter reflecting the immune-nutritional status of patients planned
for gastrointestinal surgery to assess the risk of perioperative surgery
(24,25). In our study, a PNI score of ≤40 was associated with a shorter
survival time.
In the literature, CAS patients have been evaluated with biochemical
parameters as well. Of these, NLR has been shown to be associated with
in-stent restenosis in CAS patients (26). Additionally, CRP and B-type
natriuretic peptide (BNP) have been demonstrated to have a prognostic
value in CAS patients undergoing carotid surgery (27).
Both the studies in the literature and our study indicated that
malnutrition is associated with mortality. Accordingly, the CONUT score,
which is an objective and easily applicable scoring system, can be a
useful nutritional indicator in predicting adverse events in CAS
patients and, as a novel indicator, can contribute to the prediction of
adverse events such as long-term mortality and stroke in the CAS
patients, in addition to traditional parameters.
The study had several limitations. First, it was a single-center
retrospective study and had a relatively small sample size. Second, the
CONUT scores were not assessed after hospital discharge and thus the
effect of changes in post-discharge CONUT scores on clinical outcomes
could not be evaluated. Third, malnutrition was assessed only by using
the CONUT score and PNI, and other nutritional indicators such as MNA,
SGA, and GNRI were not used.
In conclusion, malnutrition assessed by the CONUT score was associated
with poor prognosis in patients with CAS. The CONUT score is a useful
tool for risk stratification of patients with CAS.