notes by dr Claudio Italiano
Cardiovascular atherosclerotic disease is common in the general population
affecting the majority of adults over age 60.
The main characteristics can be summarized as follows:
• coronary artery disease in the form of myocardial
infarction, angina pectoris, heart failure, coronary death.
• cerebrovascular disease (Stroke, transient ischemic attack or TIA).
• peripheral arteriopathy (claudication intermittens)
• critical ischemia of the lower limbs).
• aortic atherosclerosis
or aneurysm of the thoracic or abdominal aorta.
Together with neoplasms, atherosclerotic disease is one of the main causes of morbidity and mortality; hyperglycemia, arterial hypertension, overweight with accumulation of abdominal fat in particular (see metabolic syndrome) and dyslipidemia are the main risk factors.
The prevalence of atherosclerotic coronary artery disease represents 50% of total cardiovascular disease. The Framingham study conducted on subjects free of atherosclerotic coronary artery disease, about 7,733 subjects between 40 and 94 years old, provided the first significant indications on cardiovascular risk. The risk in life of meeting a cardiovascular event was 49% in men and 32% in women.
The study was conducted on the American population of the town of Framingham and differs, as estimated by the prevalence of cardiovascular events, from studies conducted in Europe and in particular in Italy where the risk is less. An interesting evaluation is that of the SCORE study, which sees the use of European data from low and high risk populations. SCORE cards (see cardiovascular risk charts), when applied to European populations with different risk profiles, have been shown to function reasonably well. Many of the risk factors for cardiovascular disease can be modified by specific measures. The INTERHEART study conducted in 52 countries identified nine potentially modifiable risk factors that are responsible for 90% of the risk of the first event (myocardial infarction).
Risk factors include:
• smoking
• dyslipidemia
• hypertension
• diabetes
• abdominal obesity
• psychosocial factors
• daily consumption of fruit and vegetables (see diet and waste)
• regular consumption of alcohol
• regular physical activity
In this study emerged as metabolic factors are closely related to cardiovascular
risk
The calculation of cardiovascular risk for our population can be obtained by
applying the formula published in the heart project on the website
www.cuore.iss.it. Our website has also been involved (cfr
Cardiovascular risk ). The main risk indicator is the absolute
global cardiovascular risk that is able to express the probability of meeting a
major cardiovascular event by knowing the rate of some of the risk factors. We
must consider that the overall cardiovascular risk is not the simple sum of the
risk factors but multiplies to their association. Risk cards are absolute global
risk classes calculated by risk factor categories: (age, gender, diabetes,
smoking, systolic pressure and total cholesterolemia). Type 1 diabetes morbidity
is a consequence of both macrovascular (atherosclerosis) and microvascular (retinopathy,
nephropathy and neuropathy) damage. Several studies have confirmed a correlation
between poor glycemic control and complications. Micro vascular (see Diabetes
and cardiocardiovascular risk). This association had the most significant
confirmation in the Diabetes Control and Complication Trial study (DCCT), which
showed that intensive insulin therapy, with a significant reduction in glycated
hemoglobin (<7.2%) compared to the control, was accompanied by a reduction in
new cases of neuropathy, nephropathy and retinopathy and a slowdown in the
progression of the same complications. The DCCT also did not show a significant
reduction in cardiovascular events (3.2% versus 5.4% in the control group p =
0.08).
In particular, the DCCT study showed N° 1441 type 1 diabetic patients, N° 726 of whom
were without signs of complications at the start of the study, randomized to
intensive insulin therapy or conventional therapy and followed for 6.5 years on
average:
- 76% reduction in the risk of developing retinopathy
- reduction of the appearance of microalbuminuria of 39%
- non-significant reduction of cardiovascular events
Despite the cardiovascular complications and in substance the related risk exist in DMT1, their reduction was not observed in the mean 6.5 years of the DCCT trial, contrary to the effect observed on microangiopathic complications (retinopathy, nephropathy and neuropathy) of this trial, participants in the control arm were offered the opportunity to participate in intensive treatment and the follow-up ended in 1993 until 2005. Results of the EDIC study (Observational Epidemiology of Diabetes Interventions and Complications study ): at the end of the study the glycated hemoglobin level was 7.9% and 7.8%, respectively in the previously intensive arm in the DCCT and in the conventional arm in the DCCT, then switched to intensive treatment.
The outcomes of the cardiovascular study were:
Non-fatal IMA
stroke
cardiovascular death
angina documented
myocardial revascularization.
During the overall follow-up of the two studies of about 17 years, 0.38
cardiovascular events were observed for 100 patients / year in the arm coming
from the intensive treatment of DCCT and 0.80 cardiovascular events per 100
patients / year in the arm coming from the conventional treatment. This
corresponded to a 42% reduction for all cardiovascular events in the
DCCT-intensive arm compared to the conventional. In essence, the best glycemic
control in the previous period of the DCCT study explained the difference in the
final outcome of the EDIC observational study.
The EDIC study: macrovascular complications and intensive care in type 1
diabetes showed:
Intensive arm 0.38 cardiovascular events for 100 patients / year
Conventional arm 0.80 cardiovascular events per 100 patients / year
A period of good glycemic control (6.5 years in the DCCT study) eventually led to an obvious advantage in subsequent years reducing cardiovascular morbidity and mortality.
The control of hyperglycemia also in Diabetes Mellitus Type 1 is able to improve the prognosis by reducing cardiovascular events; this effect, however, becomes manifest in the long term, just as in the case of the follow-up of the DCCT and subsequent EDIC.