Predicting and Preventing Cardiovascular Events in Asymptomatic Patients: A 10-Year Prospective Study

Abstract

OBJECTIVE: Cardiovascular disease (CVD) had become a leading cause of deathamong people in developing countries including Thai military officers. No long termdata on preventing CVD events in this group had been published before.Thus, our mainstudy purposes were to identify the target individuals who carried the substantial riskof developing CVD event and prevent them in advance.

MATERIALS AND METHODS: After approved by the ethics committee and medicalorganization of Chandrubeksa hospital in 2006, all in service officers (aged of 35-60years) who undergone annual screening, were voluntarily enrolled. We excluded officerswho were beyond this age range, not willing to participate or already had CVD. Topredict the 10-yr risk of developing CVD events, we used the modified Coronary RiskChart (mCRC) (available at www@thaiafheart.com) to classify asymptomatic Air Forceofficers into three groups; the low, intermediate and the high risk candidates, accordingto the predicted cardiovascular risk of < 9.9%, 10-19.9% and > 20% respectively. Forall participants, life-style modifications was given, but medication and further screeningwith exercise stress test were provided only in the intermediate and high risk groups.All subjects were followed from 2006-2016 by an annual physical check-up. After tenyears, the clinical outcomes (acute coronary syndrome, stroke, total death and compositeevents) were compared between the three groups.

RESULTS: Of total 410 asymptomatic cases, 85.4% were men and had a mean age of50.9 ± 6.1 years. During 10-yr follow-up, we were able to track the health status of allparticipants. There was total of 52 events, with only 5 events (5.7%) occurring in thelow risk group (including one ACS, one ischemic stroke and 3 non-CVD deaths). Incontradiction, 47 clinical events (14.6%, p = 0.026 for comparison with the low riskgroup) were observed in the combined intermediate and high risk groups (including 7non-fatal ACS, 10 ischemic strokes, 2 CVD and 28 non-CVD deaths). Both ACS andstroke occurred less frequently than predicted rate and no statistical different of actualevents was noted in each assigned risk group. The incidence of ACS and stroke amongthe low, intermediate and high risk candidates were 1.1%, 1.1% and 3.8% and 1.1%,4.2% and 1.5% respectively. The mean time from entering the registry to the occurrenceof an ACS was 4.9 years and the mean age of ACS cases was 55.1 years. Stroke wasobserved 7.1 years on average after entering the registry. All of strokes were ischemicin origin and the mean age of stroke cases was 61.4 years. A total of 33 deaths (8%)occurred 3.4%, 7.9% and 11.3% among the low, intermediate and high risk individuals.Death occurred after on average 6.7 years at a mean age was 59.4 years. The CVD deathwas very low (6%), each of them were from STE-ACS and stroke. The non-cardiovasculardeath was 31 cases (94%). The common causes were cancer (n = 12), cirrhosis (n = 6),accident and drowning (n = 6). The death rate and composite outcome of ACS , strokeor death were significantly higher in the highest risk group when compared with thoseof the low risk candidates: relative risk of 3.6 (95%CI: 1-12.8), p = 0.04 and3.3(95%CI:1.2-9.0), p = 0.016, respectively.

CONCLUSION: By using the mCRC (available at www.thaiafheart.com), predictionand reduction of CVD events in asymptomatic officers were feasible. The observed ACSand stroke rate were > 50% lower than the predicted one and no statistically significancewas found among the three risk groups. Progression to ACS or stroke was observed alsoin non-high risk cases. We therefore recommend re-assessing CV risk every 3-year andre-emphasizing the importance of CV preventive measures. While he ACS and strokerates were lower than expected, we observed the high rate of non-CVD death which wassignificantly increased in the high-risk group. This group of individuals should be targetedfor further preventive measures related e.g. smoking and alcohol consumption.