LMCA: Left Main Coronary Artery; DA: Anterior Descending Artery; Cx: Circumflex Artery; CD: Right Coronary Arter

In the Table 1 a major CCS is observed, so much for the population in study as for both sexes, in the anterior descending artery followed by the right coronary, the circumflex and finally left main coronary artery. In the distribution by sex, a higher CCS was observed in the anterior descending for men (90.1AU vs 77.2AU, respectively) while in women the CCS was higher for the right coronary (74.4AU vs 51.5AU) and circumflex arteries (31.2AU vs 21.0AU), although none of these differences were significant.

Relationship of cardiovascular risk factors with the presence and severity of coronary artery calcification

In the Table 2 is presented an analysis according to quartiles of coronary artery calcification, note that age, total cholesterol and triglycerides showed a proportional and significant increase with the advance of coronary artery calcification. On the other hand, the percentage of patients with a history of alcoholism is low. No significant differences were found between the two comparison groups for sex, skin color, smoking, alcoholism, hypertension and BMI. Blood glucose levels although showing a proportional rise with the CCS increase, showed no significant differences.

BMI: Body Mass Index; *significant association; ^aChi² test; ^bStudent

Relationship between type and duration of diabetes with the CCS

*Significant association; ^achi² test

The Table 3 shows that 48.2% of type 1 diabetic patients presented a CCS >0AU establishing a significant association, not so with type 2 diabetic patients, with a predominance of patients with 0AU (77.2% vs 51.8%).

The proportional rise of the arterial coronary calcification was associated in a significant mode with an increase in the percentage of patients with diabetes type 1 (22.2% [0 AU] vs 47.8% [1-100AU] vs 36.8% [101-399AU] vs 72.7% [=400AU], respectively, p <0.001) (Table 4).

*Significant association; ^achi² test

*Significant association; ^achi² test

*Significant association; ^achi² test

The patients with some degree of arterial coronary calcification proved to be a significantly major percentage of patients with time of evolution of the major diabetes of 20 years in comparison to those with CCS in 0UA (17.6% vs 2.5%, p=0.001) (Table 5). The proportional increase of the arterial coronary calcification was associated in a significant way with an rise in the percentage of patients with time of evolution of the disease ≥20 years (2.5% [0AU] vs 0.0% [1-100AU] vs 13.2% [101-399AU] vs 45.5% [=400AU], respectively, p <0.001) (Table 6)

Discussion

Coronary calcium score per patient and per artery

In the present study, about half of the diabetic patients had some degree of coronary artery calcification, of which 36.6% had a CCS greater than 100AU. In the general population, Blaha et al. [19] in a study with asymptomatic patients report 45% with CCS=0 and 12% with CCS values of 1-10AU. In Cuba, Cabrera-Rego et al. [20] included 300 asymptomatic adults taken from the general population, in which 65.7% had a CCS between 0-10AU, 17.4% CCS between 11-99AU, 12.6% CCS between 100- 399AU and only 4.3% CCS greater than 400AU.In a recent study of 1123 patients with diabetes, the prevalence of coronary atherosclerosis was greater than that found in this study, since 86.0% of patients had a CCS greater than 10AU, while 53.0% had a CCS greater than 300 AU [21]. The PREDICT study [22] which included 589 patients with diabetes without a history of cardiovascular disease showed a CCS lesser than 10AU in 23.4% and a CCS greater than 400AU in 25.5%. Anand et al. [23], reported a higher prevalence in asymptomatic diabetics since 46.3% had a CCS greater than 10AU. In another report of 478 asymptomatic type 2 diabetics, Leem et al. [24], found that 32.8% of patients had a CCS=0AU while 31.6% had CCS between 1-100AU, 19.2% between 101-400AU and remaining 16.3% a CCS greater than 400AU. In a recent comparative study conducted in Cuba by Peix et al. [25], the CCS in diabetic patients was 74.1±168.8AU vs 5.2±14.6AU in controls, p <0.01. In the diabetic group, 13.6% had a CCS greater than 100AU. On the other hand and regarding the distribution of CCS by artery, a higher CAC was found for the anterior descending. However, gender differences were interesting, as calcium deposition was greater in women in the circumflex and right coronary arteries. Arjmand et al. [26], found similar results as CAC was higher for the anterior descending one. In a recent study by Sabour et al. [27], which included 566 postmenopausal women, 15.8% had CAC in the left main coronary artery, 43.9% in the anterior descending artery, 23.1% in the right coronary artery, and the remaining 19.4% in the left coronary artery circumflex.

Relationship between cardiovascular risk factors with the CAC's presence and severity

In the present study, age was not only significantly higher in diabetics with some degree of CAC, but a proportional increase in age was found with increasing quartiles of CCS. On the contrary, although in the patients with some degree of CAC a slightly higher percentage of males were found, these differences were not significant. In a recent report by Rodriguez et al. [28], that included 100 patients with diabetes, patients with CAC were significantly older than those with a CCS=0 (47±9 vs 37±9), although the percentage of men did not had differences between both comparison groups (67.7% vs 55.1%). In that study, the odds of increased CAC were 2.73 times greater for every additional 10 years of age. The Heinz Nixdorf Recall Study [29], which included 4814 people from the general population who were followed for a period of 5.1 years, found that CAC was present in men in 23.3% and in women in 15.3% in the group of 45 -49 years increased to 66.7% in men and 42.9% in women in the 70-74 age group. As can be seen, the percentage of calcification is consistently lower in women, and these results have been reported in other studies [30].

On the topic of the rest of the clinical variables analyzed, in this study neither skin color, smoking, history of alcoholism, hypertension and BMI were related to the presence of CAC. In the CCS quartile analysis, only the percentage of patients with a history of alcoholism was significantly lower in those with a higher CCS. In the report by Rodríguez et al. [28], the color of the skin, smoking and BMI also did not show a significant relationship with CAC in diabetic patients. In a study by Wade et al. [31], in type 2 diabetics, African Americans showed significantly lower CCS values than non-Hispanic whites for both sexes. On the other hand, Wagenknechty et al. [32] also found significantly lower values of CAC in blacks versus whites. Regarding skin color, it should be taken into account that the data obtained only by the phenotypic appearance can lead to misunderstandings, because there are patients classified with white skin that are not due to the wide miscegenation of the Cuban population.

In relation with the smoking, it is well-known that this habit promotes the atheroma's plate formation especially for the free radical derivate of cigar smoke that increases the oxidative stress and the concentration of inflammatory scoreboards. This effect is major in the smokers' diabetic population which was demonstrated in the ARIC study [33].

In an interesting way, in the study of Leem et al. [24], though the precedent of smoking did not show the relation with the increase of the CAC, one found a significant relation between this habit and the presence of plates not calcified in diabetics with CCS=0, aspect that agrees with other studies in which there it has been demonstrated that smoking is a fort predictor of not calcified obstructive plates [34]. More than half of the diabetic patients suffer from hypertension and the last one is been recognized as the most important cardiovascular risk scoreboard since there is evidence of which the pressure elevation increase the possibility of suffering ischemia heart disease. In regard to the arterial hypertension, in another study realized by Rodríguez et al. [35], in 261 diabetics type 1, the hypertense patients had to probability twice major with regard to the not hypertense ones in having to major CCS of 0 AU. In fact the HTA was the only component of the metabolic syndrome in showing relation with the CAC.

In the report of Leem et al. [24], the age, the percentage of patients of the masculine sex and of patients with arterial hypertension, increased in to proportional and significant way with the increase of CAC’s quartiles in diabetic type 2. On the contrary the BMI was a variable that did not show differences with the progression of the CAC in the present study. However other author like Rodríguez et al. [36], reported in 621 diabetics' type 1, a significant relation between the corporal overweight and the obesity with major risk of suffer CAC.

In the present study, the numbers of glycemic, total cholesterol and triglycerides were significantly major in the patients with some degree of atherosclerosis coronary whereas the total cholesterol and the triglycerides related to the progression of the CAC according to increase of CCS’s quartiles. In Rivera’s et al. [37], in 906 asymptomatic individuals without diabetes a significant relation was demonstrated between the values of glycosilated hemoglobin (HbAlc) and number of coronary segments by plate atherosclerotic. On the other hand,Schindler et al. [38], there demonstrated in diabetic type 2 that the reduction supported of the glycemic correlates with a slower progression of the CAC.

In Rodríguez et al. [28], the values of total cholesterol, triglycerides, HDL-C, LDL-C and HbAlc did not show significant differences between the diabetic patients with and without CAC. Equally; in the study of Wagenknecht et al. [32], the levels of triglycerides and HDL-C was similar between both groups of comparison. Jaechan et al. [24], did not find relation between the precedent of dyslipidemia, as well as the values of total cholesterol, LDL-C, HDL-C and triglycerides with the severity of the CAC either.

In Cuba, Buchaca et al. [18], brought in 59 patients with diabetes type 2, one major number of patients with hyperglycemia presented coronary hurt on having compared them with the patients with good glycemic control (p=0,024), relation that was more evident with the hyperglycemia postprandial. The hyperglycemia showed a probability 5.99 times major of detecting coronary injuries for tomography on having compared it with other major risk atherosclerotic factors.

Relationship between type and duration of diabetes with the CCS

In the present study, type 1 diabetes showed a greater relationship with the presence and extent of subclinical coronary atherosclerosis according to CCS. In patients with type 1 diabetes, the prevalence of CAC is 18% before age 30 and 50% at age 40, compared to 1% before age 30 and 27% at age 40 in non-diabetic adults. Contrary to our results, Djaberi et al. [39], included 135 asymptomatic diabetic patients divided into two groups according to type 1 diabetes (n=65) and type 2 (n=70). There were no significant differences in CCS between the two comparison groups in this study, although the mean CCS was higher in patients with type 1 diabetes (217 vs 174 UA). However, the prevalence of coronary atherosclerosis was slightly lower in this group than in patients with type 2 diabetes (65% vs 71%). Likewise, the prevalence of coronary obstruction was higher in patients with type 2 diabetes (34% vs 17%) as well as the percentage of patients with non-calcified plaques (66% vs 27%). Similarly, Scholte et al. [40], observed a higher prevalence of coronary atherosclerosis which generally involved more than one coronary artery in type 2 asymptomatic diabetics. On the other hand, as demonstrated in the present study, the evolution time of diabetes is one of the most important factors in the development of micro and macrovascular complications. Several studies have also reported a proportional and significant relationship between the duration of diabetes and the presence and extent of CAC [41].

Conclusion

In the investigation, it was observed that extensive coronary artery calcification is very frequent in diabetic patients especially in those with a long life; disorders of carbohydrate and lipid metabolism closely related to increased coronaryartery calcification in these patients, as well as those who have diabetes type 1 and have a longer duration of diabetes.

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