الفهرس 
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Abstract
Introduction
Cardiovascular disease (CVD) remains a worldwide leading cause of mortality and morbidity, despite the huge effort in improving clinical outcomes in recent decades.
Risk assessment and predicting survival have thus become pivotal to the prevention of CVD. Special attention is taken of some subgroups of patients, such as elder individuals and patients with diabetes or other risk factors. As the population is ageing and the prevalence of obesity and diabetes increases the need for a more personalized approach and repeated cardiovascular risk assessment is more urgent.
In addition, the assessment of the ‘high risk’ surgical patient should quantify the risk of an adverse outcome for each individual. This should be made explicit to the patient, clearly documented and used to stratify patients to receive an appropriate level of perioperative care.
Physiological markers of organ dysfunction may significantly improve risk stratification. Natriuretic peptides (NP) [i.e. brain natriuretic peptide (BNP) or NT-proBNP] are primarily released by cardiac myocytes in response to ventricular wall stretch or myocardial ischemia. Preoperative NP may become useful as a screening test to classify patients at high, equivocal or low risk of postoperative functional heart failure.
Besides the diagnostic role, ABI has a prognostic role, identifying patients with very high cardiovascular risk, independently of the presence or absence of symptoms. Compared to other diagnostic methods, ABI is superior because of its simplicity, being very easy to routinely determine in all patients and because it is a noninvasive test. Almost all major studies and international guidelines included PAD as major cardiovascular risk factor with independent role in risk stratification in patients with coronary artery disease.
Having a low ABI ratio is an independent risk factor for cardiovascular disease including fatal and nonfatal complications. In addition, the lower the ABPI value, the higher the risk of all-cause and cardiac mortality in patients with peripheral vascular disease.
The objective of our study is to evaluate the applicability of ankle brachial index, BNP (brain natriuretic peptide), pro-BNP as a cardiovascular prediction models in high risk patients (ASA III or IV) during hospital stay till hospital discharge and to determine the relationship between pathological ABI and incidence of cardiovascular events (coronary disease, cerebrovascular disease, symptomatic aneurism of abdominal aorta, vascular surgery) and death in the >60-year population.
Patients
This is a prospective observational cohort study, sixty adult patients planned for surgery were included in this study according to the following inclusion criteria; Patients 60 years or older, ASA III or IV and Operation in the lower half of the body. Excluded from the study patients with; Patient refusal and Patient with acute cardiac condition (MI, recent MI, severe valve lesion or heart failure).
Methods
All patients were premeditated with ranitidine 150 mg and midazolam 5 mg at night and 2 h before surgery with sips of water. Patients were preloaded with 10 mL/kg normal saline (NS).
Monitoring devices include standard five ASA monitors (12-lead ECG, noninvasive BP, capnography, pulse oximetry, temperature probe).
Induction of anesthesia was done with IV fentanyl 2 µg/kg and propofol. Propofol will be administered via IV infusion at 4 mg/kg (15–20 s). Atracurium 0.4- 0.5 mg/kg IVP over 60 secs to obtain muscle relaxation.
ABI measurement
ABI measurement was performed during the hospital stay and was calculated according to McDermott by measuring systolic blood pressure from the right and left brachial arteries, the right or left posterior tibial and dorsalis pedis arteries in the non-operative side, while the patient was supine -----------------------. Systolic pressure was detected with a handheld 8-MHz Doppler probe (Stereodop 448-S Ultrasomed). Noting the manometer reading at which the first pulse signal is heard and record that systolic value.
Dividing the ankle systolic pressure in the posterior tibial and dorsalis pedis arteries in the non-operative feet by the highest brachial systolic pressure from each arm; the lowest resulting value is the patient’s overall ABI.
BNP measurement
A 4 ml blood sample is collected from a femoral vein in the recorded times and samples allowed to clot overnight at 2-8°C to Centrifuge for 20 minutes at 1,000x g. serum removed and assay promptly or aliquot and the samples stored at -80°C. multiple freeze-thaw cycles were avoided. Samples are analyzed using the ELISA kit which applies to the in vitro quantitative determination of Human BNP concentration in serum, plasma, and other biological fluids. The Triage BNP Test diagnostic level to exclude heart failure is BNP < 100 pg/ml (negative). A level of > 100 pg./ml is considered positive and indicative of heart failure.
Postoperatively patients were admitted to the post-operative anesthesia care unit to observe patients for MACE ( Major adverse cardiac events ) defined as incident myocardial infarction, stroke, heart failure, atrial fibrillation, or CVD death.
Results
The current study assessed the frequency of post-operative cardiac affection among high risk patients who underwent non-cardiac surgery with general anesthesia. The study enrolled 60 patients aiming to evaluate the applicability of ABI and BNP as cardiovascular risk prediction models during hospital stay.
Out of the recruited patients; a total of 14 (23.3%) patients developed post-operative cardiac affection (MACE occurred in the PACU postoperatively) while 46 (76.7%) patients didn’t develop cardiac affection.
Both groups based on development of cardiac affection had no significant differences as regard baseline with exception of significantly higher mean age among those patients who developed post-operative cardiac affection.
Both groups had insignificant differences as regard pro-BNP and BNP at preoperative, intraoperative and postoperative time. In contrast; ABI was significantly lower among patients with cardiac affection at preoperative (1.23 ± 0.09 vs. 1.02 ± 0.09; p< 0.001), intraoperative (1.22 ± 0.12 vs. 1.14 ± 0.13; p= 0.02) and postoperative (1.22 ± 0.13 vs. 1.12 ± 0.15; p= 0.02).
Preoperatively, only one patient without cardiac affection and 13 (92.9%) patients with cardiac affection had low ABI with significant difference between both groups (p< 0.001).
In conclusion, in a contemporary cohort of community-based older adults, lower ankle brachial index was consistently and robustly associated with an increased risk of coronary heart disease / stroke in those without prevalent atherosclerotic coronary heart disease and with heart failure regardless of ASCVD history. These findings support the use of low ankle brachial index as a risk enhancer in helping guide primary prevention for coronary heart disease / stroke and suggest that ankle brachial index may be a strong, non-invasive predictor for assessing heart failure risk in older adults.