High altitude and other risk factors for coronary artery disease in Yemen; prevalence, clinical presentation, complications and prognosis
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Date
2008
Authors
Al-Huthi, Mohammed All
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Abstract
The main objectives of this thesis are to estimate the prevalence of risk factors,
to investigate the clinical presentation, complications, prognosis,
echocardiographic characteristics and coronary angiography findings among
ACS patients at high and low altitudes.
Study 1 was a retrospective review of records aimed at estimating the
prevalence of risk factors in the ACS patients living at high and low altitudes. It
was also aimed to investigate the clinical presentation and complications of
these patients. Seven hundred and sixty eight (768) ACS patients from high and
low altitudes were studied. Results of study 1 showed that the mean age of
ACS patients at high altitude was significantly younger. Heart rate, systolic
blood pressure (SBP) and diastolic blood pressure (OBP) were significantly
higher at high altitude. High altitude patients were also seen to have
significantly higher hemoglobin (Hb), hematocrit, white blood cells (WBC),
creatine kinase (CK), creatine kinase-isoenzyme (CK-MB), total cholesterol, low
density lipoprotein cholesterol (LDL-C) and triglycerides (TG). The prevalence
of past history of hyperlipidemia and history of coronary artery disease (CAD)
were significantly higher for high altitude patients. The prevalence of past
history of diabetes mellitus (OM) and smoking were higher with border line
significance for high altitude. Cardiac wall motion abnormalities detected by
echocardiography was higher for high altitude patients. Left ventricular ejection
ventricular E:jection fraction (LVEF) was significantly lower at high altitude. High
altitude patients were seen to have significantly higher rate of stroke.
Arrhythmias, heart failure and death did not show any difference.
Study 2 was a cohort study, aimed at evaluating the prognosis of ACS
among patients at high and low altitudes. One hundred and fifty seven (157)
ACS patients from high and low altitudes were evaluated from admission to
CCU for up to 12 months. Results of study 2 showed that the mean age of ACS
patients at high altitude was younger. Heart rate, SBP and DBP were higher for
patients at high altitude. High altitude patients had higher CK-MB, WBC, total
cholesterol, LDL-C and random blood glucose. The prevalence of past history of
hyperlipidemia among ACS patients was higher for patients at high altitude. Left
ventricular ejection fraction during hospitalization was lower for high altitude
patients. Beta-blocker use was significantly higher at low altitude. Usage of
thrombolytic agent, heparin, aspirin, angiotensin converting enzyme inhibitor
(ACE-I), nitrates, lipid lowering agent, diuretics, and calcium channel blocker
(CCB) were comparable. After six months of follow up, HR, SBP, DBP and
incidence of heart failure were higher for high altitude patients. At the end of 1
year follow up, high altitude patients were seen to have higher HR, SBP, DBP
and have more diagnostic coronary angiography done. Heart failure was more
frequent among high altitude patients and L VEF was lower for high altitude
patients. Betq-blocker use was significantly higher at low altitude, the rest of
medication usage were comparable.
Study 3 was a retrospective review of records aimed at investigating
echocardiographic characteristics and severity of coronary artery occlusions
among high and low altitudes ACS patients. Records of six hundred and two
(602) ACS patients from high and low altitudes who underwent diagnostic
coronary angiography were reviewed. Results of study 3 showed that the mean
age of high altitude patients who underwent coronary angiography was
younger. High altitude patients were seen to have higher HR, SBP and DBP.
The prevalence of past history of hyperlipidemia and history of CAD were
significantly higher for high altitude patients. Reported family history of CAD
was significantly higher among low altitude patients. The prevalence of history
of OM and smoking for patients at high altitude were higher with border line
significance. Left ventricular ejection fraction was lower for high altitude
patients. Three vessel occlusions were significantly more common for patients
at high altitude while single vessel occlusion was significantly more common for
low altitude patients. High altitude patients were seen to have more occlusions
in circumflex coronary artery (CX), left anterior descending artery (LAD) and
right coronary artery (RCA).
In conclusion, in Yemen, ACS occurs at younger age in high altitude
residence. High altitude ACS patients also have more prevalent cardiovascular
risk factors. They also demonstrated more severe coronary lesion and more
adverse clinical outcome. These findings suggest that high altitude itself should
be considered as an independent risk factor for ACS.
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Keywords
Coronary artery , Prognosis