IMPACT OF EXCESSIVE WEIGHT LOSS ON CARDIOVASCULAR RISK AFTER TWO YEARS OF BARIATRIC SURGERY CARDIOVASCULAR RISK AND BARIATRIC SURGERY

Overweightness is related to a high incidence of dyslipidemia, being considered a risk factor for cardiovascular diseases. Objective: Analysis of the effect of weight loss in reducing type 2 diabetes mellitus and cardiovascular risk 2 years after Roux-en-Y gastric bypass. Methods: A retrospective study with patients who underwent Roux-en-Y gastric bypass involving accessing the database of an Obesity Surgery Clinic from March 2018 to March 2019. Male and female patients, aged 18 and over, who underwent bariatric surgery from March 2014 to March 2016 were analyzed. The following data were obtained from the medical records of patients: body weight, height, age, sex, glucose and glycated hemoglobin (HbA1C) after 24 months of surgery. Results: In total, 351 patients were studied, 80.9% of whom were female. There was a reduction in weight and in the concentrations of all biochemical parameters, except HDLc, along with a decrease in the frequency of dyslipidemia and cardiovascular risk 24 months after surgery. When comparing variations between 6 and 12 months, only group 1 reduced Hb1Ac and decreased CVR. There was a significant reduction in the level of glucose in group 1 (p = 0.036) at T4 (18 months) and T5 (24 months). Conclusion: The positive impact determined by bariatric surgery on weight loss was shown to be effective in improving the dyslipidemic profile, reducing morbidities associated with obesity and, consequently, reducing CVR after 24 months. Gastric


Introduction
Obesity is a public health problem due to its increasing prevalence and high mortality rate. It also determines an increase in the frequency of chronic diseases [1], which further intensifies morbimortality in super-obese patients [2]. These diseases include those considered to be cardiovascular risk factors (CVRFs) such as systemic arterial hypertension (SAH), type 2 diabetes mellitus (T2DM) and dyslipidemia [3][4]. The obesity treatment involves drug and nutritional therapy, along with physical activity; however, these methods do not produce satisfactory results in the most severe cases, with 95% of individuals returning to their initial weight within two years [5][6]. The frustratio n of super-obese patients with the slow advances in conservative treatment motivates them to go through bariatric surgery (BS) due to its speed and effectiveness in the treatment of obesity. Patients who are suitable for bariatric surgery are those with clinical treatment failure and with a body mass index (BMI) above 35 kg/m² and associated comorbidities, or patients with a BMI >40 kg/m². The health effects of bariatric surgery are satisfactor y in the quality of life of patients, in addition to improvements in health conditions related to obesity and pre-existing comorbidities (glycemic levels, hypertension, 2 diabetes mellitus, hepatic steatosis, sleep apnea and reflux) [7][8][9]. Bariatric surgery has been used as a treatment for the super-obese patients and is an effective and lasting interventio n, showing therapeutic success in relation to excess weight loss (% EWL), in addition to a substantial improvement in comorbidities [10][11]. A meta-analysis with 134 studies involving 22,000 obese individuals has showed that gastric bypass determines, on average, a 61% reduction in EWL, 39.7 kg reduction in body weight, 13.2 kgm 2 reduction in BMI and a significant improvement or resolution of comorbidities [12]. The highest excess weight loss and the most beneficial effect on comorbidities occur approximate ly one year after surgery, remaining in most patients [13][14]. Much of this effect, however, can already be seen within the first six months [13]. Thus, understanding the anthropometric profile and the comorbidities of patients undergoing bariatric surgery is essential to measure the risks related to the morbimortality of the surgery and to provide resources, special care and postoperative support [15]. Considering this growing number of obesity cases in the population worldwide and the consequent increase in the number of bariatric surgeries, this study aims to evaluate the effect of excess weight loss in the solution of 2 diabetes mellitus and CVR), using the Framingham Risk Score [16] two years after bariatric surgery.

Results
The number of evaluated patients who underwent Gastric Bypass was 351. The sample of this study consisted of 284 women (80.9%) and 67 men (19.1%), aged between 20 and 70 years old and with an average age of 42.1 ± 11.2 years. The mean and standard deviation values of the continuous variables in the preoperative evaluation such as body weight and BMI are described in Table 1 according to the criteria established by the Ministry of Health [19] for the indication of Roux-en-Y gastric bypass. All 351 individuals underwent one anastomosis gastric bypass (OAGB), thus constituting the study sample. The prevalence of associated comorbidities is higher among females in this study ( Table   2).  decreased the CVR (p = 0.001). There was no difference between the two groups at T3-T4 (12-18 months). There was a significant reduction in the glucose level in G1 <70% (p = 0.036) at T4-T5 (18-24 months).
Graph 1 shows the variation in the levels of glycated hemoglobin (HbA1c) in patients in G1 (<70% EWL) and G2 (≥ 70% EWL) during the two years after bariatric surgery. It was found that all patients were overweight and had altered glycated hemoglob in (HbA1c) (5.7-7%) in the preoperative period (T1). There was a reduction in weight and HbA1c in both groups with a statistically significant difference (p = 0.000) after the procedure in T2 (6 months) and T3 (12 months). On the other hand, the group that lost less weight (G2) showed a reduction of Hb1Ac up to T3 (12 months) and a stability from (12) maintained a similar behavior to G1 up to T3 (12 months). After 12 months, they showed a significant increase in Hb1Ac until T5 (24 months).

Discussion
The analyses of preoperative comorbidities have shown that 291 patients (82.9%) had some morbidity. Thus, obesity is a clinical condition that forms a risk factor for other diseases. The most common comorbidities were hypertension (55.27%), T2DM (24.5%) and dyslipidemia (58.4%). These data were also found in other studies [31][32][33][34]. Sanches-Santos and collaborators [35] highlighted that 85.7% of 50 patients achieved improvement in comorbidities associated with obesity five years after Roux-en-Y gastric bypass. Most patients undergoing bariatric surgery in this study were female (80.9%), which confirms the results of other studies carried out in different regions of the country [2,13,21]. Unlike women, men (19.1%) tend to seek this possibility of BS only when their daily physical activities are compromised [24]. According to Sandoval [20], clinica l treatment in morbidly obese individuals results in a reduction of only 5-10% of body weight (rarely maintained), whereas gastric bypass determines a weight reduction of around 50%, with results maintained in the long-term. By analyzing the link between bariatric surgery and the impact on excess weight loss, it is noticed that bariatric surgery has been proven to be quite effective [32][33][34][35], with the mean pre-surgical BMI being 42.6 kg/m 2 ± 4.65 and the post-surgical being 26.7 kg/m 2 ± 4.5. Patients reduced around the % EWL (± 70%), which implies a significant reduction in cardiovascular mortality as well as mortality from all causes associated with excessive weight. Similar data have been reported by other authors such as Costa et al., [28] who found satisfactory % EWL (% EWL >50%) in 94.7% of the analyzed patients. Glycated hemoglobin in G2 (≥70%) showed a reduction up to 12 months and stability from 18 to 24 months. Patients who lost more weight (G1 = <70%) maintained a similar behavior of Hb1Ac up to 12 months.
Schauer and collaborators [37] found a reduction of (-2.9 ± 1.6%) in glycated hemoglob in in 12 months of follow-up. Other authors [38,36]  A decrease in glucose after T4 (18 months) was observed and is shown in Graph 2. It is observed that glycemic control is an alteration that occurs quickly after the surgical intervention and is maintained over the long-term. Other authors [13,22,23,26,30] also highlighted the results found in this study. Studies with longer follow-up showed higher percentages of patients with normal blood glucose values [27,29]. After 6 months of follow-up, Parikh [41] found 65% of patients with HbA1c <6%; at 12 months, Shauer et al. [37] observed that 42% of their patients had these results; at 18 months and Kashyap et al. [39] found an 80% diabetes remission rate; and Hsu and collaborators [40] obtained a rate of 53% of individuals with normal glycemic control after 5 years, which is considered prolonged remission. It was observed that with a longer follow-up, glucose decreased to 64.7mg/dL at 24 months postoperatively and Hb1Ac at 6 months postoperatively was already 5.5% in this study. Regarding CVR, it was found that in the preoperative period (T1), all patients had a 31% probability of cardiovascular problems within 10 years, which was considered a high risk of cardiovascular complications. There was a reduction in cardiovascular risks with weight loss and a reduction in metabolic rates (glucose and HbA1c) after 6 months of surgery (T2) in both groups (G1 and G2).
However, the group that showed a statistically significant difference was G1 with a reduction in CVR at T2 (p = 0.045) and T3 (p = 0.001), explaining the decrease in glucose and Hb1Ac with weight loss. Patients did not show a statistically significant difference at other times. The weight loss obtained within 24 months (73.2%) was similar to that found by Ferraz et al. [43] (78%). Other studies have found a reduction of 59.2% EWL and 64% EWL in the same period of time [36,42]. Rapid weight loss in the first six months and up to 24 months is an important factor in reducing the metabolic and lipid profile, in addition to being important for reducing risk factors for cardiovascular diseases. However, there was a slight correlation between weight loss and CVR after six months, which is maintained up to 24 months of the surgery. Garcia-Diaz et al. [44] reported the impact of gastroplasty on the reduction of excess body weight and on the control of cardiovascular risk factors (CVRFs) one to three years after surgery, considering this period most relevant clinically. Within that period, a reduction of 20 to 50 kg in body weight is expected, around 35% in BMI and the resolution of systemic arterial hypertension (SAH), type 2 diabetes mellitus (T2DM) and dyslipidemia in 62%, 76% and 70% of individua ls, respectively [12,24,25,26]. This study has shown that the expected and described results have already been observed at the end of the sixth month after gastroplasty and they remain at the end of the 24 months in both groups surveyed. When evaluating the effect of excess weight loss on the reduction of CVR and the control of T2DM, it can be said that bariatric surgery has been efficient in controlling the parameters evaluated in this study.

Method
This is a retrospective, descriptive and cross-sectional study with a quantitative approach Framinghan Heart Study Score [16] was used in order to establish the Cardiovascular Risk. Framingham is a cohort study that has been active since 1948. The Framingha n Score assesses the likelihood of a cardiovascular event such as a heart attack or stroke in the next 10 years. The probability of these cardiovascular accidents is expressed in terms of the degree of risk: low, moderate and high. In order to assess the risk (calculation), the They were categorized in G1 with weight loss <70% EWL and G2 with weight loss ≥70% EWL according to Deitel and Shikora [18].

Statistical Analysis
The data were inserted into the Microsoft Excel 2010® program and, double-checked and transferred to the IBM SPSS® program (Statistical Package for Social Science), version 20.0. The results were considered statistically significant at p < 0.05 for all statistical data.
The analyses of the quantitative data were described by average and standard deviatio ns.
The median and interquartile range were used in the breakdown of distributio na l assumptions. Categorical data were described by counts and percentages. The analysis of longitudinal variability of the quantitative medians (glucose, CVR, Hb1Ac) was evaluated by using Generalized Estimation Equations, taking the interaction model between the two groups as factors: G1 (<70%) and G2 (≥70%).
Based on the results presented in this study, it is possible to conclude that there was a positive impact determined by gastric bypass on the loss of excess weight (EWL) and a reduction of the biochemical parameters related to glucose metabolism and CVRF; they are extremely significant after six months of surgery and maintained after 24 months, which indicates that bariatric surgery is effective in losing weight with an improve me nt in anthropometric, metabolic and biochemical parameters and in reducing morbidities associated with obesity.