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Double Trouble - Diabetes and Heart Disease (CAD) 297

sity to increased coagulability. Diabetics have higher also been observed in patients with diabetes based
rates of platelet activation, and increased levels of on Doppler studies. Interstitial fibrosis with increased
tissue plasminogen activator inhibitor type 1, leading collagen deposition has been postulated as contrib-
to accelerated thrombus formation and reduced ly- uting to the altered mechanics. The prevalence of
sis of clot. Moreover, proteinuria due to diabetic ne- heart failure, especially heart failure with preserved
phropathy can reduce the levels of protein C and an- ejection fraction(16-31%) is higher among diabetics
ti-thrombin III, furthering the pro-coagulant state. (3) than the general population (4-6%). Thus diabetes
per se independently influences cardiac structure
Silent Ischemia and function by promoting hypertrophy and fibrosis.
Some diabetics may have a blunted pain response
to ischemia, which may result in atypical symptoms.
This may result in silent ischemic insult to the cardiac
musculature and eventually, silent infarction. Silent
ischemia is far more prevalent in patients with DM
(10%-20%) than those without DM (1%-4%) and may
have a male predilection. Silent Myocardial infarction
may contribute to the higher rates of morbidity and
mortality in cardiovascular disease among diabetics.
Silent ischemia is partly explained by the autonom-
ic neuropathy seen in diabetes. The astute clinician
therefore, must have a low threshold for suspecting
cardiac ischemia in a diabetic patient with atypical
symptoms and early evaluation is prudent.

Asymptomatic disease:
People with diabetes have higher rates of asymptom-
atic disease (11 to 60%). This has been studied based
on the presence of coronary artery calcification (CAC)
on electron beam CT scanning and by inducible silent
ischemia on stress imaging. The American Diabetes
association (ADA) and European guidelines, howev- D. Diabetes as a risk factor for cardiovascular disease:
er, do not recommend routine screening for coronary
artery disease in asymptomatic patients as outcomes There are multiple identified risk factors for coronary
are not improved as long as cardiovascular risk fac- artery disease amongst which diabetes is an import-
tors are controlled. (4) ant modifiable factor. The cardiovascular risk identi-
fied with that of diabetes has been compared with
Diabetic Cardiomyopathy: the cardiovascular associated with a prior myocardial
infarction. Diabetics have a greater burden of other
Diabetes affects the heart in more ways than just cor- atherogenic risk factors than nondiabetics, including
onary atherosclerosis and the effects of associated hypertension, obesity, increased total to HDL choles-
systemic hypertension. Diabetics tend to have great- terol ratio, hypertriglyceridemia, and elevated plasma
er cardiac muscle mass, especially of the left ventri- fibrinogen. The CAD risk in diabetics varies widely
cle. One multi-ethnic study showed that the likeli- with the intensity of these risk factors
th
hood of having a left ventricular mass exceeding 75
percentile was greater in type 2 diabetics even after E. Cardiovascular Risk and targeted reduction in di-
adjusting for other factors. This has been attributed abetes:
to higher levels of leptin and resistin which contrib- In patients with diabetes, multiple risk factors that
ute to hypertrophic effects on the cardiac myocytes. predispose to coronary artery disease have been
Studies have shown that 40-75% of diabetics with no identified. These include both traditional and non-tra-
overt signs of coronary artery disease have diastolic ditional risk factors.
dysfunction. This finding has been explained based
on triglyceride accumulation in cardiac myocytes in
diabetes, which results in lipotoxicity and altered
calcium metabolism. Subtle systolic dysfunction has

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