Cardio-Ankle Vascular Index in Diabetes or MetS
The results of this study show that the CAVI is positively associated with IMT, cf-PWV, ba-PWV, CAIx, and PAIx, regardless of cardiovascular risk and the drug treatment used. Patients with cardiovascular TOD have higher values of CAVI. Likewise, the CAVI was positively correlated with age, HbA1c, SBP, and DBP, and it was negatively correlated with waist circumference and body mass index.
Similar to the data found in this work, the CAVI was positively related with carotid IMT, cf-PWV, and ba-PWV in type 2 diabetes mellitus patients. These results suggest that CAVI is a useful clinical marker for evaluating atherosclerosis in subjects with increased insulin resistance. Likewise, Kadota et al. suggested the use of CAVI as a screening tool for atherosclerosis based on their findings from a general population study of 1014 adults showing strongly significant associations of CAVI scores with carotid intima-media thickness. Takaki et al. compared the utility of these two parameters to detect arterial stiffness. Both CAVI and ba-PWV were significantly correlated with age and IMT. However, only CAVI was correlated with the parameters of left ventricular diastolic indices from echocardiography. Finally, only CAVI was significantly higher in the group with angina pectoris, and all parameters associated with atherosclerosis suggested that CAVI is superior to ba-PWV as a parameter of arterial stiffness.
Similarly we found an association between CAVI and ba-PWV or cf-PWV. The extent of atherosclerosis has been estimated using ba-PWV, ba-PWV are independently associated with the presence of coronary artery calcium (CAC), a marker of preclinical atherosclerosis, but this can be influenced by blood pressure, and it is not very reproducible. Because the CAVI is independent of BP, highly reproducible, easy to apply, and does not require special techniques, its potential as a novel parameter of atherosclerosis has recently become recognized. Izuara et al. suggested that CAVI reflects systemic arterial sclerosis, including carotid atherosclerosis and coronary atherosclerosis, and that CAVI might be more useful for discriminating the probability of coronary atherosclerosis than findings of carotid atherosclerosis by high-resolution ba-PWV.
As far as we know, this is the first study that describes a positive association between the CAVI, the CAIx, and PAIx. Assessment of CAIx is a simple approach to quantify the role of wave reflection in determining an elevation of central blood pressure values. Contrary to data published by Masugata et al., who found a relationship between CAVI and the presence of left ventricule hypertrophy, this study found no relationship with either the left CAVI ventricule hypertrophy, renal TOD, the thickness of arteries and veins of the retina, or the ratio between the two.
In previous studies in Japanese population, has been described a negative association of CAVI with estimated glomerular filtration and a positive correlation with the albumin creatinine ratio. In our study, probably due to the low statistic power by the small sample size, we found no correlation with any of these parameters.
Consistent with previous studies, we found a positive correlation of CAVI with age, SBP, and DBP. Our study revealed that CAVI is highly correlated with age (r = 0.65), similar to the results reported by other authors for diabetic subjects and for hypertensive diabetics (r = 0.63). A study that examined 32627 healthy residents from Japan showed that CAVI increases almost linearly with age from 20 to 70 years in males and females by 0.5 over 10 years.
The positive correlation between CAVI with SBP and DBP remains after adjusting for age, sex, and drug therapies used by patients. The results are consistent with those reported in diabetic patients. However, in hypertensive patients, a correlation has only been found between CAVI and SBP, but not with DBP. Some authors such as Nakamura et al. found no association of CAVI with blood pressure in patients with coronary disease. These discrepancies suggest that the relationship of CAVI with the different components of blood pressure could be conditioned by previous disease presenting in the subjects analyzed.
Consistent with published results for patients with and without diabetes, the CAVI was positively correlated with HbA1c (r = 0.298, p < 0.05). In summary, these results suggest that CAVI is a good tool to detect the presence of vascular TOD, carotid atherosclerosis, and arterial stiffness in Caucasian patients with increased insulin resistance, and they may be helpful in clinical practice for this patient group, completing the results published by Takata et al. in 2013 for an Asian population.
The main limitation of this study was the source of the data for the cross-sectional study, which prevented us from establishing a temporal relationship between the CAVI and the different FRCV, TOD, and parameters that assess vascular function and structure during one week. Also, at the time of viewing these results, the subjects included in the study had multiple associated pathologies and were being treated with many drugs, which may have affected the CAVI values. We have tried to control this limitation by including the drugs most frequently used in the multiple regression analysis and in the correlation analysis as adjustment variables. Finally, the sample size of the individuals analyzed is not large.
Discussion
The results of this study show that the CAVI is positively associated with IMT, cf-PWV, ba-PWV, CAIx, and PAIx, regardless of cardiovascular risk and the drug treatment used. Patients with cardiovascular TOD have higher values of CAVI. Likewise, the CAVI was positively correlated with age, HbA1c, SBP, and DBP, and it was negatively correlated with waist circumference and body mass index.
Similar to the data found in this work, the CAVI was positively related with carotid IMT, cf-PWV, and ba-PWV in type 2 diabetes mellitus patients. These results suggest that CAVI is a useful clinical marker for evaluating atherosclerosis in subjects with increased insulin resistance. Likewise, Kadota et al. suggested the use of CAVI as a screening tool for atherosclerosis based on their findings from a general population study of 1014 adults showing strongly significant associations of CAVI scores with carotid intima-media thickness. Takaki et al. compared the utility of these two parameters to detect arterial stiffness. Both CAVI and ba-PWV were significantly correlated with age and IMT. However, only CAVI was correlated with the parameters of left ventricular diastolic indices from echocardiography. Finally, only CAVI was significantly higher in the group with angina pectoris, and all parameters associated with atherosclerosis suggested that CAVI is superior to ba-PWV as a parameter of arterial stiffness.
Similarly we found an association between CAVI and ba-PWV or cf-PWV. The extent of atherosclerosis has been estimated using ba-PWV, ba-PWV are independently associated with the presence of coronary artery calcium (CAC), a marker of preclinical atherosclerosis, but this can be influenced by blood pressure, and it is not very reproducible. Because the CAVI is independent of BP, highly reproducible, easy to apply, and does not require special techniques, its potential as a novel parameter of atherosclerosis has recently become recognized. Izuara et al. suggested that CAVI reflects systemic arterial sclerosis, including carotid atherosclerosis and coronary atherosclerosis, and that CAVI might be more useful for discriminating the probability of coronary atherosclerosis than findings of carotid atherosclerosis by high-resolution ba-PWV.
As far as we know, this is the first study that describes a positive association between the CAVI, the CAIx, and PAIx. Assessment of CAIx is a simple approach to quantify the role of wave reflection in determining an elevation of central blood pressure values. Contrary to data published by Masugata et al., who found a relationship between CAVI and the presence of left ventricule hypertrophy, this study found no relationship with either the left CAVI ventricule hypertrophy, renal TOD, the thickness of arteries and veins of the retina, or the ratio between the two.
In previous studies in Japanese population, has been described a negative association of CAVI with estimated glomerular filtration and a positive correlation with the albumin creatinine ratio. In our study, probably due to the low statistic power by the small sample size, we found no correlation with any of these parameters.
Consistent with previous studies, we found a positive correlation of CAVI with age, SBP, and DBP. Our study revealed that CAVI is highly correlated with age (r = 0.65), similar to the results reported by other authors for diabetic subjects and for hypertensive diabetics (r = 0.63). A study that examined 32627 healthy residents from Japan showed that CAVI increases almost linearly with age from 20 to 70 years in males and females by 0.5 over 10 years.
The positive correlation between CAVI with SBP and DBP remains after adjusting for age, sex, and drug therapies used by patients. The results are consistent with those reported in diabetic patients. However, in hypertensive patients, a correlation has only been found between CAVI and SBP, but not with DBP. Some authors such as Nakamura et al. found no association of CAVI with blood pressure in patients with coronary disease. These discrepancies suggest that the relationship of CAVI with the different components of blood pressure could be conditioned by previous disease presenting in the subjects analyzed.
Consistent with published results for patients with and without diabetes, the CAVI was positively correlated with HbA1c (r = 0.298, p < 0.05). In summary, these results suggest that CAVI is a good tool to detect the presence of vascular TOD, carotid atherosclerosis, and arterial stiffness in Caucasian patients with increased insulin resistance, and they may be helpful in clinical practice for this patient group, completing the results published by Takata et al. in 2013 for an Asian population.
Limitations
The main limitation of this study was the source of the data for the cross-sectional study, which prevented us from establishing a temporal relationship between the CAVI and the different FRCV, TOD, and parameters that assess vascular function and structure during one week. Also, at the time of viewing these results, the subjects included in the study had multiple associated pathologies and were being treated with many drugs, which may have affected the CAVI values. We have tried to control this limitation by including the drugs most frequently used in the multiple regression analysis and in the correlation analysis as adjustment variables. Finally, the sample size of the individuals analyzed is not large.