ANTEGRADE FLOW AND PERIPHERAL RESISTANCE DETERMINE THE LEVEL OF ENDOGENOUS ARTERIOGENESIS IN PATIENTS WITH SUPERFICIAL FEMORAL ARTERY OCCLUSION
Atherosclerotic blocks in the limb artery leads to decreased blood supply and ischemia. Due to these atherosclerotic blocks in artery causes the more effective natural respond like arteriogenesis. Some clinical features like poor run-off, impact on vessel growth is not known.
Methods: To know the atherosclerotic blocks in arterogenesis they conduct a study population on patients who has been under taken bypass surgery for lower limb ischemia due to blockage of superficial femoral artery and clinical data was collected and reviewed by counting the number of collateral vessels bypassing the blocked segments and record the inflow and outflow vessels. The methods that are conducted are angiographic analysis and statistical analysis.
Results: according to analysis results found are mean number of collaterals was 13 +/- 0.5 patients. In univariate analysis shows the short daily walking distance, chronic leg ischemia, low ankle brachial index and in multivariate analysis shows the quality of inflow and the number of patent calf vessels demonstrated an independent association.
The main aim is research on natural development of new blood vessels in patients who has underwent the superficial femoral artery damage.
Before research done by Eur J Clin Invest in 2009, Lower limb ischemia in humans is due to the main reason of thickening and hardening of the walls of arteries due to fat remains in their inner lining of arteries. Damage of arteries alters the extension of existing vessels and develops a new blood vessel from the pre-existing vessels. Hypoxia and inflammation are the causes for tissue neovascularisation. Hypoxia-inducible-factor (HIF) is act as a master switch protein binds to promoters of hypoxia genes and introduces the angiogenesis and protective metabolic responses. To increase the angiogenic and arteriogenic factors, T-lymphocytes and macrophages are recruited as inflammatory signals into the ischemia region. To bring out the neovascular response hypoxia and inflammation are interdependent, from the pre-existing vessels new blood vessels are developed due to the hypoxia-dependent. Collateral artery growth is controlled by the factors inflammation and haemodynamics. Due to increased fusion of cytokines, shear stress, inflammation, and vascular growth factor build the Angiogenesis and arteriogenesis. Haemodynamics acts as a major role in preventing the damage of arterial system. In vitro and in vivo study endothelial cells modified their structure and function by mechanical forces and shear stress, these forces changes the gene expression.
Many experimental and clinical studies were conducted resulting that growth of blood vessels and collateral arteries are seen in adults. The aim of the study was: (i) to find out factors affecting the development of collateral arteries and (ii) to find clinical parameters that predict collateral density in patients with lower limb ischaemia.
Generally research is conducted on patients(N=96), at Kuopio University Hospital, between the January 2004 and December 2005 was reviewed. Patients medical data and preoperative angiograms are arranged for femoropopliteal or femorodistal revascularization at the section of vascular surgery. Study conducted on a patients who are under going to surgery for chronic leg ischaemia or claudication due to damage of superficial femoral artery(SFA) along the popliteal artery and one distinct calf artery. Patients who are suffering from high aortic stenosis or those underwent treatment with ipsilateral surgical bypass repair are not included in the study.
At last research is conducted on 70 patients of study population, from this study demographic data, risk factors and comorbidities(two or more medical conditions) was studied and recorded, and more information on disease onset, continuation of symptoms, phase, useful capacity, claudication and ankle or brachial indexes are registered.
This study design was approved by the ethical committee of the Kuopio University Hospital.
Techniques used in the study were angiographic analysis and statistical analysis.
Angiography is a procedure performed to view the blood vessels after injecting them with a radio opaque dye that outlines them on x-ray. This technique is used to look at many arteries in the body.
Angiographic analysis performs a study on complete quantification and qualification of collateral vessels bypassing the blocked superficial femoral artery (SFA). By means of digital subtraction angiography (DSA) workstation software (Sweden) we can perform the re elaboration of angiogram, even smallest collateral vessels also seen by adjusting zoom, contrast and brightness parameters. Image reading was study individually by two vascular surgeons (IV, JK) patient medical history. By evaluating the arterial vessels bypassing a horizontal plane at proximal, medial and inferior blocked superficial femoral artery part was registered. Inflow and outflow of stenoses and distinct outflow arteries under the knee was recorded and also measured the length of the block of superficial femoral artery.
The collateral count of two patients of their mean difference and standard deviation are small, collateral count is highest but the difference is small on transversing counting line of blocked femoral artery section. This line is used to analyse the patient by readind the mean value on the line.
Statistical analysis include the unpaired t-test and one way ANOVA test, these are used to test the difference in repeated and identified variables.
One way ANOVA test:
This is a technique used to treat more than two groups to be compared simultaneously.
Pearson's correlation (continuous variable) and Spearman's Rho correlation (categorized variables) are used to test the interactions among the variables. If the risk factors of collateral vessels of univariate analysis introduce into regression analysis to determine the independent factors causing the formation of collateral vessels. Statistical analysis represents the results as mean +/- standard error of mean (SEM). Less than 0.05 is limit for statistical significance, all the statistical procedures was performed using SPSS software