HIV infection is associated with an increased cardiovascular risk t therefore new tests are needed to allow an early diagnosis. Our study is the first study, to our knowledge, which evaluates endothelial dysfunction markers such as EPCs, BHI and FMD and subclinical atherosclerosis markers such as IMT and coronary calcium score in the same patients with HIV infection and studies their relationship with HIV related parameters such as viral load and CD4 cells.
In this study, as shown in other publications, IMT in patients with HIV infection is associated with classic cardiovascular factors such as age and sex as in general population . Regarding the relationship of the IMT and the immunological situation o, we found a tendency to a lower ratio of CD4/CD8 cells among patients with pathological IMT although without statistical significance. Similar findings have been published . In addition, in this study it was observed that patients who presented a pathological IMT had a lower value of CD4 cells at the time of study inclusion. Previous studies have observed that patients with a < 200 CD4 cells have a higher IMT and the progression over time of IMT is faster than in those with normal immunological situation [9, 26].
Regarding the Coronary Calcium Score, in this study the patients whom the calcium score was > 100 AU not only had a lower CD4 cells value at the moment of the study inclusion and a lower nadir of CD4cells, but also had a higher zenith VL in a significant way.
The information obtained from the literature about the association between the quantification of coronary calcium and the parameters related to HIV is controversial. In other study of similar methodologic characteristics, no association was observed between lymphocyte subpopulations and VL with coronary calcium score in patients with HIV infection. This fact is probably related to greater prevalence of classic vascular risk factors in the included population, since the patients were older and a large percentage of them were smokers (63%) . However, in other studies with a lower percentage of smokers, whom people included is more similar to our population, the progression over time of coronary calcium score was related to the viral load of the patients the coronary and to the number of CD4 cells [12–13].
We did not find a significant association between FMD and the different parameters related to HIV infection, although there was a tendency towards a greater FMD among patients with a worse immunological and virological status and longer infection time. We found a study whose methodology for the measurement of FMD is the same as the technique performed in our study and no differences were found in FMD in the different subgroups of patients with HIV infection, in the same way as in our study .
However, other studies have found an association between FMD and HIV related parameters and globally the FMD values were overall lower than in our study . This may be related to the fact that the patients with HIV infection included in that study did not receive HAART and that we do not know if the methodology for measuring FMD was the same as in our study. Another study compared FMD of patients with HIV infection receiving HAART and naive patients, in the naive subgroup the vascular reactivity was greater than in the group of patients receiving treatment, contrary to the tendence observed in our study . This data may be related to a poorer lipidic control and a higher percentage of smokers among patients already receiving HAART.
In our study, patients who presented a higher zenith VL had a lower cerebral vascular reactivity close to statistical significance. We did not find an association with CD4 cells value. In addition, patients longer since HIV diagnosis and those who did not received treatment during long periods of time had also a worse BHI. Patients with a pathological IMT and a calcium score > 100 UA had a lower BHI.
HIV infection has been associated with lower cerebral reactivity without relationship between BHI and CD4 cells  and with a trend toward higher cerebral vasoreactivity for each additional year of viral suppression . This data is also in accordance with our findings, as patients with a high VL had a worse BHI.
In our cohort patients with a lower CD4 cells nadir and with a higher zenith VL had a lower blood concentration of early and very early EPCs although without statistically significant differences. Patients with longer time of HAART, more time of infection and more time without treatment had a minor concentration of EPCs. There are few studies that have determined EPCs in patients with HIV infection. In the Seang et al study  EPCs were measured in 57 HIV positive men and the concentration was lower than in our study with more patients with no cells detected. This fact may be related to a higher prevalence or classic cardiovascular risk factors in their patients, which were older, and dyslipidemia and diabetes were more frequent. No No association was found between EPCs and HIV related parameters.
Papassavas et al  determining the same type of EPCs as ourselves, and a direct association between early EPCs and CD4 cells was observed. However, in the rest of the studies, this relationship was not found neither with VL [23–24]. In all the studies that have determined EPCs in patients with HIV infection except in the Costinuk et al , included smokers patients, and it is difficult to draw conclusions if we take into account that nicotine alters the proliferation of EPCs.
The lack of a consensus definition in other articles of the EPCs [22–24] and the heterogeneity of classic cardiovascular risk factors of their populations makes it difficult to obtain conclusions from them.
Our study has several limitations. Firstly, the lack of a control group (patients without HIV infection) since it does not allow us to know the values of the endothelial function tests and subclinical atherosclerosis in relation to the virological status of the patient. However, it is known that patients with HIV infection are related to a greater vascular risk and our objective was to know the HIV related parameters that guide us to carry out diagnostic tests for early detection of atherosclerosis.
Secondly the small sample size decreased our power to detect relationships between diagnostic tests and HIV related parameters. However, the careful selection of patients without cardiovascular risk factors and non-smoking patients made it possible to eliminate confounding factors and to relate VL and CD4 cells with some of the selected tests.