Original Article OPEN ACCESS

Background: The effector AvrPiz-t of Magnaporthe oryzae has virulence function in rice. However, the mechanism underlying its virulence in host is not fully understood.


Introduction
Although the established risk factors such as smoking [1], high blood cholesterol levels [2] and hypertension [3] have shown to be associated with the development of coronary artery disease (CAD), defining the role of blood pressure changes for predicting CHD remains clinically challenging.A report indicated that fractional pulse pressure (FPP) [4] was closely related to cardiovascular diseases.However, it is little known about the relationship between fractional systolic pressure (FSP)/fractional diastolic pressure (FDP) and CAD.
Therefore, the present study was to study whether FSP and FDP in central aorta were associated with CAD, and acted as a predication indicator for the severity of CAD.

Patients and Methods
The study was approved by review body of t he Henan Province Hospital, and informed consent was obtained from each subject or patient.A retrospective chart review of all p atient records with diagnostic coronary angiography between January 2000 and December 2007 was performed.A total of 310 patients were included in this study, and all patients were undertaken with diagnostic coronary angiography.According to the findings of coronary angiography, the patients were divided into two groups: CAD and non-CAD (Table 1).
The diagnoses of CAD using coronary angiography were based on the angiographic study, in which at least one of major coronary artery was shown to be 50% or more stenosis in diameter.Gensini Score was use d for determination of the severity of CAD.

Angiography
Coronary angiography was performed by femoral or transradial approaches.The left anterior descending artery, circumflex artery and right coronary artery were stu died.50% or more stenosis in diameter in one or more of the arteries was defined as CAD.

Measurement of central blood pressures
While an angio graphic catheter was positioned at t he ascending aorta, and connected to a fluid-filled system pressure transducer, the pressure curve was record by a multipurpose lead system.Central systolic blood pressure (SBP), central diastolic blood pressure (DBP) and mean blood pressure were obtained from the re corded curve.The SBP and D BP were recorded upon the 1 st and 5 th Korotkoff sound, respectively.
The mean arterial pressure (MAP) and pulse pressure (PP) were obtained for calcu lation of FSP and FDP, in which the equation was: FSP=SBP/MAP, and FDP=DBP/MAP.

Measurement of blood lipids
All individuals in the present study were tested with their blood lipid, including total cholesterol, triglycerides, apolipoproteins, and high/low lipoprotein.

Statistical analysis
Quantitative data was exp ressed by mean ± SD.One-way ANOVA and t-test were used to a nalyze the differences between the groups.A value of P <0.05 was considered statistically significant.

Results
310 patients were successfully undergone with coronary artery angiography.154 patients (54.7 years + 9.4) were categorized as CAD, and 156 (38.2 years + 11.4) as non CAD (Table 1).There were 157 males and 153 fem ales.No significant difference was observed in the female-to-male ratio.Th e age was si gnificantly lower in CAD patients than non-CAD.
There was a significant difference in central SBP/FSP and FDP between the two groups (P<0.01).The elevated FSP increased the risk of CAD, while elevated FDP decreased the risk of CAD.The level of the blood lipid did not show a significant difference between the two groups.

Discussion
CAD remains the leading cause of death, and early detection of CAD allows optimal therapeutic management.The gold standard for diagnoses of CAD has always been invasive coronary angiography.Ascending aortic fractional pulse pressure and fractional systolic pressure were demonstrated to differentiate patients with and without coronary artery disease [6].In addition, central FSP and FDP were shown to be related to risk of CAD [7], and a higher central FSP or lower central FDP will increase the risk of CAD [8, 9].However, there is no study available on the relationship between FSP/FDP and the exte nt of coronary artery disease, We identified 154 patients with CAD.Our results showed that central FSP and FDP are independent risk factors for CAD with higher FSP and lowe r FDP, and act as a n indicator of higher risk for CAD.In addition to the central FSP and FDP as an independent factor for risk and severity of CAD, the Gensini Score is also demonstrated to be a risk factor for evaluation of CAD .The present findings demonstrated that FSP and FDP combined with Gensini Score were not only a satisfied ex amination of patients with and without CAD, but provided with a much reliable predicting indicator for the risk of CAD.Atherosclerotic vascular disease is common in el derly patients.Even though a high incidence of CAD was demonstrated to be associated with atherosclerosis [10], which was studied by coronary artery angiography [2], our results showed that the level of blood lipid was not an independent factor for the prediction of CAD.This might be due to the test carried ou t at the different stages of disease.Therefore, we do not rec ommend the blood-lipid test alone to be an i ndependent factor for the severity of CAD.

Conclusion
Our results reported here show that central FSP and FDP combined with Gensini Score were an independent risk factor for CAD.This is of significant importance for the diagnosis and severity of CAD.

Table 1
Mean age and groups of the study population Ueda H, Hayashi T and Yoshikawa J. Pulsatility of ascending aortic blood pressure waveform is associated with an increased risk of coronary heart disease.Am J Hy pertens 2001; 14:469-473.9. Nakayama Y, Hayashi T, Yoshimaru K, Tsumura K and Ueda H. Low fractional diastolic pressure in the ascending aorta increased the risk of c oronary heart disease.J Hum Hypertens 2002; 16(12):837-841.10.Besler C, Hein rich K, Riwanto M, Lusch er TF, Landmesser U. Hi gh-Density Lipoprotein-Mediated Anti-Atherosclerotic and Endothelial-Protective Effects: A Poten tial Novel Therapeutic Target in Cardiovascular Disease.Curr Pharm Des 2010 Mar 3. [Epub ahead of print]