Diastolic Dysfunction of the Left Ventricle in a Prediabetic Population from Rural Central India

According to a growing body of research, in people with type 2 diabetes mellitus (T2DM), cardiovascular diseases are a leading cause of mortality. Many studies have sought to understand the many pathways that may play a role in CVD in diabetics in a significant way. According to research, pat had a much higher overall morbidity and mortality rate. The culprits are hyperglycemia-induced macrovascular diseases, autonomic neuropathy, and generally diabetic cardiomyopathy, which is quite significant. Diabetic people might be diagnosed with cardiomyopathy even if they generally are initially asymptomatic and show no clinical indications of the disease, or so they essentially thought. Echocardiography provides the opportunity to measure systolic and diastolic function, which is explicitly fairly significant. A significant risk factor for developing diabetes appears to be prediabetes with the risk of conversion is approximately 70% in the next ten years, with similar microvascular and cardiovascular consequences to diabetes. Immunological factors, Cytokines, advanced glycosylation end-product accumulation and oxidative stress, a standard processes involved. Diastolic dysfunction alters diastolic filling and increases isovolumetric relaxation time in diabetic patients. One of the independent markers for assessing the propensity of developing Cardiovascular disease in a diabetic population is Insulin Resistance. On the other hand, normotensive patients have been linked to left ventricular dysfunction, even when Study Protocol Bajpai et al.; JPRI, 33(62B): 457-471, 2021; Article no.JPRI.80708 458 omitting those with coronary artery disease (CAD), which is quite significant for all intents and purposes. According to experts at the Indian Institute of Cardiology (ICC) in Bangalore, even people with normal blood pressure and prediabetes exhibit asymptomatic diastolic dysregulation.


INTRODUCTION
According to a growing body of research, cardiovascular diseases are in large part accountable for the numerous deaths that occur in people with Type 2 Diabetes Mellitus. Many researchers have stated various mechanisms that can lead to CVD in such cases. The chances of developing cardiovascular disease are conclusively increased with conditions such as diabetes, obesity, ageing & hypertension [1]. Studies conducted on diabetic populations have shown an overall increase in mortality and morbidity. Credit goes to hyperglycemia-induced macrovascular diseases, autonomic neuropathy, and diabetic cardiomyopathy. Diabetic subjects, if initially asymptomatic, showing no early signs clinically related to cardiomyopathy, can still be detected to have cardiomyopathy with the assistance of echocardiography. A significant risk factor for developing diabetes appears to be prediabetes, with complications comparable to diabetes. Not much data has been provided in the past studies regarding the association between a decline in Left ventricle performance and the condition of prediabetes, compared to the vast quantity of data found in favor of an association between diabetes and left ventricular dysfunction [2]. Researchers mainly have laid down generally many hypotheses on the pathogenesis concerning the injury inflicted to the cardiac myocytes , the dilatation of the ventricles in the heart, and disordered functioning of the myocardium, out of which the most common mechanisms include immunological factors, Cytokines, advanced glycosylation endproduct accumulation, and oxidative stress [3][4][5]. Moreover, 8% of the American population has diabetes, which is pretty significant [6].
The weighted overall comparison between the occurrence of prediabetes and diabetes in Jharkhand, Tamil Nadu, Maharashtra and Chandigarh, was, 5.3% (95% CI: 4.5-6.1%), 10.4% (95% CI: 9.0-11.0%,8.4% (95% CI:7.5-9.3%) and 13.6% (95% CI:12.8-15.2%) versus , 8.1%, ,8.3%, 12.8% and 14.6% respectively. Differently put, the population suffering from diabetes vs. prediabetes in the state of Jharkhand, Chandigarh, Tamil Nadu, and Maharashtra has shown to be 0.96 million vs. 1.5 million,0.12 million vs. 0.13 million,4.8 million vs. 3.9 million, 6.0 million vs. 9.2 million respectively, with the highest prevalence was observed in Chandigarh, then Maharashtra, followed by Tamil Nadu and finally Jharkhand [7]. Estimated risk of conversion to diabetes from prediabetes in the next ten years appears to be approximately 70%, with similar macrovascular, microvascular, cardiovascular complications as seen typically in diabetes. The condition of prediabetes has been defined as having an impaired tolerance to glucose measured Two hours after an oral dose of 75 grams of dextrose with the plasma levels of glucose ranging between 140 to 199 milligrams per decilitre alternatively having the blood glucose levels after fasting between 110 to 125 milligrams per decilitre or glycosylated hemoglobin levels in blood between 5.7 to 6.4% [HbA1c] [8][9][10][11]. An increment of 20% in the risk of developing cardiovascular disease has been noted compared with people who do not have hyperglycemia. A dysfunction of beta cells in the pancreas and resistance to the insulin hormone is presumed to be a common pathophysiological disturbance in both prediabetes and diabetes mellitus [12]. Various studies have shown that cardiovascular mortality is similar in both diabetes and prediabetes, which shows us the requirement of aggressively managing these two hyperglycemic populations [13][14][15][16][17][18]. The ability to assess systolic and diastolic function has been offered through echocardiography. Increased time to isovolumetric relaxation and a decrease in ejection time and the fraction is seen with a dysfunction of the systolic performance of the Left ventricle.
On the other hand, diastolic dysfunction results in an increased time required for isovolumetric relaxation, altering the filling of blood in the ventricle during the diastolic phase [19,20]. Studies have shown that in people with type 2 diabetes, the incidence of this dysfunction is increased. One of the independent markers for assessing the propensity of cardiovascular disease in a diabetic population is Insulin Resistance which also plays a pathogenic role in the disease [21,22].

Rationale
Resistance to insulin and intolerance to glucose can be associated with dysfunction of the myocardium since they frequently precede the development of frank diabetes. On the other hand, T2DM, normotensive subjects excluding those with diseased coronary arteries, have shown a correlation to left ventricular dysfunction. Not much light is shed on the adverse effects that prediabetes can have on the diastolic, and systolic functions of the left ventricle. This study will explore the effects prediabetes has which cause diastolic dysfunction, using conventional 2D echocardiographic techniques.
There are numerous studies done outside India, and even normotensive prediabetes subjects have asymptomatic diastolic dysfunction. However, In India, only two studies describe diastolic dysfunction among patients with T2DM [23,24]. We cannot identify any studies from India which have related diastolic dysfunction among the prediabetes population.

Aim
To find out how joint left ventricular diastolic dysfunction (LVDF) is in Prediabetics from a rural area of central India.

Objective(s)
1) To compare the diastolic function of the left ventricle in prediabetic subjects with Age and sex-matched controls from the rural area of central India.
2) To ascertain the correlations between cardiometabolic risk factors and diastolic dysfunction of the left ventricle in prediabetic individuals.

Background
The study will be conducted in the Acharya Vinoba Bhave Rural Hospital (AVBRH), a 1200 bedded, tertiary care teaching hospital in Wardha district with around 1.2 million.

Type of Study
This study will be a case-control study.

Subject Selection
1. Persons with prediabetes and age and sex match controls attending the medicine department AVBRH must be interviewed and examined for the diastolic dysfunction of the left ventricle.

Criteria for Inclusion
Case: -Individuals diagnosed with Prediabetes by the guidelines laid down by the WHO [32]. -Age: more than 25 years old but less than 50 years old 60 years. -Gender: male and female.
-Consent: persons who are voluntarily willing and capable of giving consent will be inducted into the study.

Controls:
-Age: two years on either side of a prediabetic case and is of the same gender. They will also have the below-mentioned exclusion criteria.
 Diabetes (as per who criteria).
 Diseased Heart valves.
 Coronary heart disease.

 Tobacco user
Harmful use of alcohol [33].

Sample Size
The desired minimum sample size is 100, assuming a 50% prevalence of left ventricular diastolic function in prediabetic subjects with a confidence interval of 95%, 10% being the Absolute precision. Due to the Lack of any population-based research about the prevalence of left ventricular diastolic function in people with type 2 diabetes from rural India and Factoring in a confidence level of 95% with an absolute precision of 10%, we will assume prevalence of left ventricular function in pre-diabetes to be 50% since this yields the maximum sample size. Therefore, the total sample size will be 200 (100 prediabetes and 100 age/sex match control). Past medical records/documents wherever available will be studied. History of, diabetes, Ischaemic heart disease,heart failure & hypertensive disorders will be enquired ,recorded in

Method(S)
A biochemical investigation like FBS, PMBS, FLP will be done, and anthropometric measurements will be taken.
And finally, an echocardiography examination will be carried out.

Data Collection
A questionnaire will be designed to collect information regarding demographics, Age, Sex, presence of any cardiovascular diseases, Significant family history, dyslipidemia, hypertensive disorders, and a sedentary lifestyle, as they are all risk factors. Tobacco and alcohol abuse are both hazardous (all forms). The questionnaire will be pilot tested before data collection.
Persons with prediabetes attending AVBRH will be interviewed with the help of the questionnaire. Informed written consent will be taken in their mother tongue, and participants guaranteed their privacy. They will be interviewed in the Marathi language. Socio-demography information, family history of diabetes or CVD, anthropometric measured waist circumference, hip ratio, height, weight, BMI, blood pressure, pulse.
All patients will be subjected to anthropometric measurements and BMI and will be investigated for, FBS, PMBS and a fasting lipid profile , including the Total serum cholesterol levels and serum Triglycerides, and HDL-C, LDL-C VLDL-C levels. Accepted lab techniques will be employed for all the biochemical measurements.
Each participant's blood pressure is measured two times while in a sitting position using a mercury sphygmomanometer, the mean of the measured values is used for analysis. Using standardized equipment and procedures, Bodyweight in kilograms, waist and hip circumference in centimeters, and height in meters will be measured [34]. To determine bodyweight measured to within the closest half a kilogram, subjects will standstill with their feet separated, ensuring equal weight distribution on both legs on the measuring scale. The subject's body height is measured to within closest half a centimeter against a vertical scale. The inferior margin of the subject's bony orbits has to be at the same level as the top part of their external auditory opening of the ears.
Body Mass Index, [kg/m 2 ], can be calculated by dividing the body weight in Kilograms with height in meters.
The waist circumference is measured when the individual is standing. The particular individual holds up the gown as the examiner stands behind them, palpating the hpg area and the right iliac crest. The examiner draws a horizontal line from the highest point on the subject's iliac crest to their mid-axillary line and then crosses it. The examiner stands on the subject\'s right side and wraps the measuring tape horizontally around the trunk at the level designated on the trunk\'s right side. The recorder moves around the person to verify that the tape essentially is parallel to the ground and very taut but without crushing the skin [35].
Measurement of Hip Circumference: The subject stands straight, feet together, and bodyweight equally distributed over both feet, holding up their examination gown. The recorder stands explicitly behind the patient and folds the material with their thumb to, for the most part, gather the side seams of the test pants above the hips. The examiner squats on the subject's right side and puts the measuring tape around the buttocks, while the recorder securely grips the folded sides of the subject\'s exam trousers, which is pretty significant. A measuring tape is wrapped around the hips at their widest point. At the same time, inspecting the front and sides, the recorder checks that the tape\'s plane is horizontal and aligns the sides of the measuring tape.
The zero end of the measuring tape is held below the measurement. At the broadest extent of the buttocks, the hip circumference is measure [36].
The tape should be held parallel to the floor level where the measurements are taken. It should not be grasped so tightly that it hinders the subject's mobility (WHO, 2008b). Use a stretch-resistant tape with a special indication buckle that ensures a consistent tension of 100grams; this avoids changes in the tightness of the tape around the subject\'s body. As a result, it is preserved with sufficient tenacity, which is fairly significant [36,37].
Detailed clinical cardiovascular examinations are then performed for heart rate, abnormal heart sounds, and murmurs.
Then the subject will undergo echocardiography.

BIOCHEMICAL PARAMETER ESTIMATION
Under all aseptic precautions, from the vein of the subjects, a blood sample is collected in the bare bulb and fluoride bulb, respectively.
The sample is immediately centrifuged, and serum will be separated.
Biochemical parameters will then be analyzed by RANDOX DAYTONA (Made in Japan) (Fig. 2) random analyses by turbidimetry.

Specimen Collection
Venous blood sample after eight hrs. of fasting is to be collected in fluoride bulb and bare bulb for FBS, FLP respectively and Venous blood sample after 2 hrs. Of the meal for PMBS in fluoride bulb.

Total Serum Cholesterol Estimation
The total serum cholesterol is estimated using the CHOD-PAP method, which is liquid stable using the Semi-auto chemical analyzer, Robotnik.

Specimen Collection
Overnight fasting of at least ten to 12 hours, venous samples subjects are taken collected in a bare bulb.

Procedure
1000µL of reagent is added to 10µL of plasma (dissolved in anticoagulant). Incubation is done for 15 minutes at room temperature and read by the Robotnik analyser.

Serum Triglycerides Levels Estimation
I am using a GPO -PAP method which is liquid stable using the Robotnik analyzer.

Procedure
1000µL of reagent is added to 10µL of plasma. Incubation is done for 15 minutes at room temperature and read by Robotnik Analyser.

Serum HDL Level Estimation
Utilising the Direct Enzymatic Method with the Robonik Analyser.

Procedure
375µL of HDL -D reagent 1(L1) is mixed with 5µL of the calibrator and 5µL of the sample.After incubating the sample at room temperature for five minutes, read the calibrator absorbance (A 1 ) & test against blank, HDL -D REAGENT 2 (L 2) 125µL is added and mixed with a five minute incubation at room temperature. Read Calibrator absorbance (A 2 ) & test against blank. The change in absorbance ΔA is calculated for both the calibrator and test.

Examination by Echocardiography
Philips HD 11 XE echo machine with 2-4megahertz multi-frequency probe will be used for this study (Fig. 3).
For the best acoustic window, patients should be evaluated in the left lateral decubitus posture. After doing a sector scan to acquire four chambers, a two-chamber 2D echo (CW and PW) evaluation particularly is done in a big way. Several observations and measurements must be made and documented on the standard proforma sheet. All observations will be subjected to routine statistical analysis at the end of the research, and conclusions will basically be formed, contrary to popular belief. The Simpson's rule is currently one of the most often used methods for calculating ventricular volumes (rule of the disks), which is quite significant. An apical, four-and/or two-chamber picture particularly is to generally be acquired at end-diastole and endsystole, from which the endocardial boundary actually is to be defined, contrary to popular belief. Along its basically long axis, the ventricle is mathematically split into a series of discs of equal height, which is quite significant. Individual disc volume actually is calculated as the product of disc height and disc area, with disc height assuming the entire length of the left ventricle long axis and the number of discs or segments (area = r2), or so they thought. Finally, the ventricular volume is calculated by subtly adding the discs' volumes in a subtle way. [Table 01] demonstrates this strategy in a subtle way [38]. The difference between diastolic and systolic volumes can be used to for all intents and purposes calculate stroke volume after measuring diastolic and systolic volumes. In the absence of mitral or aortic insufficiency, forward cardiac output basically equals the product of heart rate times stroke volume. The difference between diastolic and systolic left ventricular volume, which is the total volume pumped by the ventricle, represents the sum of forward stroke volume plus mitral and aortic regurgitation volume, if present. The ejection fraction may be calculated by dividing the stroke volume by the end-diastolic volume, which is quite significant [38].
Without using planimetry, the Left Ventricular Ejection Fraction (LVEF) can be calculated by measuring 8 averaged Left Ventricular internal dimensions at various levels of the left ventricle in the parasternal long-axis, apical four chambers, and long-axis views at end-diastole (LVEDD) and end-systole (LVESD), while accounting for long-axis contraction. Significant wall motion difficulties and deformed ventricles are among the limitations [39,40].
The sort of transmitral flow velocity profile specifically is then estimated from the for all intents and purposes apical four-chamber perspective using the pulsed wave Doppler sample volume positioned at the tips of mitral leaflets during diastole. The apical long-axis view is used to record the left ventricular outflow velocity pattern, with the pulsed wave Doppler sample volume positioned directly below the aortic valve. For each measurement, five successive beats must specifically be measured and averaged [41]. To quantify left ventricular diastolic function, Doppler interrogation of transmitral velocity at actually early (E) and late (A) left ventricular filling was utilised. The mitral inflow definitely signal will be used to determine the velocity of A, E & the ratio between the two, along with time required for deceleration during the early phase of diastolic filling in the left ventricle. Furthermore, a raw measurement of for all intents and purposes active left ventricular relaxation measured between aortic valve closure and mitral valve opening is the time required for isovolumetric relaxation. Averaging many cardiac cycles yields offline Doppler values. At the same time, the heart rate will basically be measured [42]. The average of Three simultaneous beats are taken with a pulsed wave tissue Doppler imaging at the junctions situated on the lateral & septal mitral annulus. E'medial and E'lateral early diastolic velocities are recorded, and the mean value (E' average) is computed from E' at the medial and lateral mitral annuli. The ratios E/Medial, E/Lateral, and E/E'(average) are calculated. Dysfunction of the diastolic performance is defined by the european & american echocardiography socitie's consensus reports as a complete assessment of diastolic function utilising standard techniques of Doppler tissue imaging. (Table 2).  (Table 3)

STATISTICAL ANALYSIS
All analyses must be carried out using Stata data analysis and statistical software (Stata 14 software). Unless otherwise noted, the data are provided as the average for variables that are continous or as a percentage for variables that are categorical in nature. A value for Pearson's coefficient being less than zero point zero 5 are considered significant and require a Bonferroni correction when comparisons are multiple.when comparing 2 groups that are independent in nature, Wilcoxon-Mann-Whitney-Test is used whereas when comparing 2 or more independent groups of samples the Kruskal Wallis test is used. When comparing two sets of binary data, Fisher''s test will be used, and when comparing generally more than two sets of category variables, the c2 test will be used. Pearson\'s linear correlation coefficients will be generated to evaluate a probable relationship between variables.By using multivariate analysis for regression models of logistic and covariance, which integrate the features that are highly predictive for the dependent variables. The important outcome variables specifically are left ventricular diastolic function [IVRT, E/A ratio, Deceleration time, e′ (septum), e′ (lateral), E/e′ ratio (septum), E/e′ ratio (averaged). The prevalence of left ventricular diastolic function is estimated and compared in patients with prediabetes and healthy people (with a 95 percent confidence interval). Numerous cofounders, such as age, smoking, and dyslipidemia, will be considered in the weighted analysis.

Definitions
The following definitions are being adopted for the purpose of the study:

Prediabetes
Fasting plasma glucose level from (110 mg/dL) to (125 mg/dL) (This test measures blood glucose in people who are fasting for at least 6--8 hours).
Post-meal plasma glucose levels are between 140 to 199mg/dl (after 2 hours of the meal) WHO criteria.

Normoglycemia (controls)
An FBG or Fasting plasma glucose level < 110 mg/dL (This test measures blood glucose in people who are fasting for at least 6--8 hours) post-meal plasma glucose levels less than 140 (after 2 hours of the meal) WHO criteria.

Overweight
Participants in the study will be categorised based on their BMI according to WHO recommendations, enlisted in [ Table 3 ]. The definition of Abdominal Adiposity is determined by circumference of the subject's waist being greater than one hundered and two centimeters in males and greater than eighty eight centimeters in females, and a ratio of hip to wait circumferences of one centimeters in males and zero point eight in females [44].
Blood pressure: A subject is said to have Hypertension when the readings of systolic & diastolic pressures is greater than Hundred and forty and Ninety millimeters of mercury or being on blood pressure-lowering medication being based on the guidelines laid down in accordance with 8th report by the Joint National committee [45].
Hypercholesterolemia: Optimal levels of serum lipid levels are determined Using the recommendations given by the Adult Treatment Panel III (NCEP ATP III) mentioned in [Table 4] [46].
Tobacco use: Tobacco use in smoked or nonsmoked forms , currently or in the past by the subjects is considered a risk factor.
Detrimental alcohol use : According to the guidelines laid down by the American Diabetes Association ,alcohol intake is greater than one daily drink for females (>10g alcohol) or two or more daily drinks for males (>20 g alcohol).

Definition of Diastolic Heart Failure
When the ventricular chamber is unable accept blood volumes sufficient for maintaining adequate pressures during the diastolic phase or for maintaining an optimal stroke volume , diastolic heart failure is said to have occurred. This is often accompanied by a decreased relaxation of the ventricle or an increased stiffness of the same.
Signs & symptoms due to heart failure can emerge which is classified into classes I through IV by the new york heart association based on the functional limitations of activity.

Definition of Diastolic Dysfunction
Diastole is the moment when the myocardium loses its ability to generate force, shortens, and then reverts to its former length and force. Diastolic dysfunction occurs when these processes are slowed, stopped, or are insufficient. The measurements that reflect changes in this normal function are primarily influenced by the decline in pressure and filling of the ventricle in terms of the rate, extent and the onset. Using Wiggers' classic concepts or Brutsaert constructs the correlations between volume & pressures or strain-stress during diastolic phase, can be defined. .If we assume that the diastolic function is normal the volume at the end of diastole of the ventricle along with the stroke volume , heart rate & blood pressures must remain normal at rest or under the stresses generated by a change in volume at the end of diastole, stroke volume, blood pressure and heart rate.

DISCUSSION
Echocardiography provides the opportunity to measure not only systolic but also diastolic function, which specifically is fairly significant. A significant risk factor for developing diabetes appears to be prediabetes with risk of conversion is approximately 70% in the next ten years, with similar microvascular and cardiovascular consequences to diabetes. Immunological factors , Cytokines , advanced glycosylation, end product accumulation and oxidative stress are some of the common processes involved. Diastolic dysfunction alters diastolic filling and increases isovolumetric relaxation time in diabetic patients. One of the independent markers for assessing the propensity of developing Cardiovascular disease in a diabetic population is Insulin Resistance. Normotensive patients, on the other hand, have been linked to left ventricular dysfunction, even when omitting those with coronary artery disease (CAD), which for all intents and purposes is quite significant [47][48][49][50][51].

CONCLUSION
Prediabetes has a significant prevalence amongst the Indian population. Most patients are often asymptomatic and thus unaware of their condition until symptomatic Diabetes mellitus has set in. Prediabetes can damage the cardiovascular system in a fashion akin to Diabetes mellitus itself. This study aims to establish the aforementioned facts using robust, anthropometric ,Biochemical and Radiological modalities to help patients and physicians in early detection and management of the same . Additionally , prompt treatment during the Prediabetes phase of the illness can prevent or at least delay the progression to diabetes mellitus and the associated complications ,with cheap oral hypoglycaemic agents and regular monitoring,a notion backed by substantial evidence.

DISCLAIMER
The products used for this research are commonly and predominantly use products in our area of research and country. There is absolutely no conflict of interest between the authors and producers of the products because we do not intend to use these products as an avenue for any litigation but for the advancement of knowledge. Also, the research was not funded by the producing company rather it was funded by personal efforts of the authors.

CONSENT
As per international standard or university standard, respondents' written consent will be collected and preserved by the author(s).

ETHICAL APPROVAL
The study will be initiated only after receiving the Clearance from the intuitional committee on ethics at DMIMS (DU), Sawangi, Wardha.

COMPETING INTERESTS
Authors have declared that no competing interests exist.