Nabil Farag

Endothelial Nitric Oxide Synthase (G894T) Gene Polymorphism in a Random Sample of the Egyptian Population: Comparison with Myocardial Infarction Patients

AIM The aim of this study was to detect endothelial nitric oxide synthase (eNOS) Glu298Asp gene variants in a random sample of the Egyptian population, compare it with those from other populations, and attempt to correlate these variants with serum levels of nitric oxide (NO). The association of eNOS genotypes or serum NO levels with the incidence of acute myocardial infarction (AMI) was also examined. METHODS One hundred one unrelated healthy subjects and 104 unrelated AMI patients were recruited randomly from the 57357 Hospital and intensive care units of El Demerdash Hospital and National Heart Institute, Cairo, Egypt. eNOS genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism. Serum NO was determined spectrophotometrically. RESULTS The genotype distribution of eNOS Glu298Asp polymorphism determined for our sample was 58.42% GG (wild type), 33.66% GT, and 7.92% TT genotypes while allele frequencies were 75.25% and 24.75% for G and T alleles, respectively. No significant association between serum NO and specific eNOS genotype could be detected. No significant correlation between eNOS genotype distribution or allele frequencies and the incidence of AMI was observed. CONCLUSION The present study demonstrated the predominance of the homozygous genotype GG over the heterozygous GT and homozygous TT in random samples of Egyptian population. It also showed the lack of association between eNOS genotypes and mean serum levels of NO, as well as the incidence of AMI.

Use of biplane transesophageal echocardiography as the only imaging technique for percutaneous balloon mitral commissurotomy

Percutaneous balloon mitral commissurotomy with the Inoue technique was attempted in 9 patients with rheumatic mitral stenosis under the sole guidance of biplane transesophageal echocardiography and was completed in 8 patients. This preliminary experience points to the feasibility and relative safety of performing percutaneous balloon mitral commissurotomy under the sole guidance of biplane transesophageal echocardiography.

Relationship between cardiovascular risk as predicted by established risk scores and coronary artery plaque composition as detected by virtual histology intravascular ultrasound analysis: the PREDICT pilot study.

AIMS Identification of subclinical high-risk plaques is potentially important because they may have greater likelihood for rupture and thrombosis. The aim of this study was to assess the relationship between in vivo coronary artery plaque composition using intravascular ultrasound virtual histology (IVUS-VH) and cardiovascular risk as predicted by clinical risk scores in patients with non-obstructive stable coronary artery disease. METHODS AND RESULTS Forty patients undergoing elective coronary angiography revealing <50% coronary artery stenoses were prospectively included. Of these, 38 (29 men; mean age 65+/-9 years) underwent a satisfactory IVUS-VH investigation of the affected vessel. For each patient, the 10-year risk of cardiovascular events was calculated using the Framingham and the SCORE-Deutschland risk prediction algorithms, and compared to the VH-derived plaque composition at the site of the minimal lumen area (MLA). For both algorithms, patients at low estimated risk of events showed more fibrous tissue percentages than patients at high risk (67.4+/-9.7% versus 53.2+/-10.4% for the SCORE algorithm, and 65.6+/-13.4% versus 51.5+/-9.4% for the Framingham algorithm, p=0.002 and p=0.004, respectively). Plaques of patients with higher risk showed a non-significantly higher necrotic core percentage. For the SCORE algorithm, dense calcium percentage was higher in patients with high risk compared to patients with low risk (13.9+/-10.4% versus 4.9+/-4.9%, p=0.008). The prevalence of IVUS-derived thin cap fibro-atheromas at the MLA site was higher in patients at high risk (80% of lesions in patients at high risk using the SCORE algorithm and 92% of lesions in patients at high risk using the Framingham algorithm), whereas patients at low risk had more stable plaque phenotypes (p=0.002 and 0.003 for the SCORE and Framingham algorithms, respectively). CONCLUSIONS In vivo plaque composition and morphology assessed by IVUS-VH were related to the cardiovascular risk predicted by established risk prediction algorithms in patients with non-obstructive coronary artery disease, suggesting a link between the higher risk for future events and the VH-derived plaque morphology.

Role of Irbesartan in Prevention of Post-Coronary Artery Bypass Graft Atrial Fibrillation

Background and ObjectiveAtrial fibrillation (AF) is a common complication of cardiothoracic surgery (CTS). Existing evidence about the potential protective role of angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]) for post-CTS AF has been limited and conflicting. In this single-blind, open-label, randomized prospective pilot study, we evaluated the potential protective role of irbesartan (an ARB) in post-coronary artery bypass graft (CABG) AF.MethodsA total of 100 consecutive patients undergoing CABG were randomly assigned to irbesartan (n = 50) versus no irbesartan (n = 50) for 5 days prior to the scheduled surgery. Data were collected for imaging studies, laboratory values, and peri-operative details. Patients were monitored post-operatively for in-hospital AF episodes. Unadjusted and adjusted logistic regression analysis was performed to assess the effect of irbesartan on the incidence of post-CABG AF.ResultsA total of 14 patients developed AF during their post-operative hospital stay. The incidence of AF in patients who received irbesartan was 6% (n = 3) compared with 22% (n = 11) in patients who did not receive irbesartan (p = 0.021). Univariate logistic regression analysis identified irbesartan and age as statistically significant variables. An adjusted multivariate logistic model identified irbesartan as an important protective factor against development of post-CABG AF (adjusted odds ratio [OR] 0.20; 95% confidence interval [CI] 0.04, 0.94; p = 0.04). Increasing age (adjusted OR 1.09, 95% CI 1.01, 1.17; p = 0.03) was also identified as an independent risk factor for development of post-CABG AF.ConclusionPretreatment with irbesartan tends to have a significant protective effect against the occurrence of AF during the post-operative period in patients undergoing CABG.

Association of manganese superoxide dismutase Ala16Val polymorphism in the incidence of acute myocardial infarction in the Egyptians

Background: Oxidative stress has been implicated in various diseases including atherosclerosis; the most common pathologic process underlying acute myocardial infarction (AMI). The manganese superoxide dismutase (MnSOD) antioxidant enzyme affords the major defense against reactive oxygen species (ROS) within the mitochondria. MnSOD Alanine16Valine (A16V) single nucleotide polymorphism (SNP) has been shown to decrease MnSOD detoxification activity. Aim: A case-control study was conducted to investigate the association between MnSOD A16V polymorphism and the incidence of AMI in the Egyptians, investigate the contribution of oxidative stress represented by hexanoyl lysine adduct (HEL), an oxidative stress biomarker, in the pathogenesis of AMI and finally correlate the MnSOD genotypes with HEL serum levels. Methods: A total of 200 Egyptian subjects were recruited for the study; 100 AMI patients and 100 control subjects. Genotypes of the MnSOD A16V polymorphism were determined using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Serum HEL was measured by ELISA. Results: A significant difference in the distribution of the MnSOD A16V genotypes was observed; VV genotype was significantly higher in AMI than controls (p ≤ 0.0001). Also, studying the allele frequencies revealed that Val allele was significantly higher in AMI than controls (p ≤ 0.0001). Serum analysis showed higher levels of HEL in AMI patients (p = 0.0142). Furthermore, HEL levels were found to be significantly higher in VV genotype in AMI (p = 0.0273). Conclusions: Our study suggests that MnSOD A16V polymorphism is associated with increased risk of developing AMI in the Egyptians. Moreover, the VV genotype is associated with higher HEL levels.

Assessment of myocardial viability using early systolic mitral annular motion velocities responses to dobutamine infusion in patients with previous myocardial infarction

Background Dobutamine stress echocardiography (DSE) is widely used for detection of myocardial viability. The main limitation of DSE is its subjective interpretation. Assessment of mitral annular motion velocities with tissue Doppler imaging is simple and quantitative measurement. Objective It is to determine the relationship between myocardial viability and regional systolic mitral annular motion velocity response to dobutamine stress in patients with previous myocardial infarction with pulsed tissue Doppler imaging (TDI). Methods Our study group included 101 patients with previous myocardial infarction. All the patients underwent conventional DSE and dobutamine stress tissue Doppler echocardiography (DSTDE) measuring velocities of presystolic wave (SW1) and peak systolic wave (SW2) at rest and during low-dose dobutamine infusion. Results After exclusion of the normokinetic walls, we analyzed 505 walls.( Table 1 ) Using the conventional DSE as the gold standard for detection of myocardial viability, the sensitivity of the DSTDE using SW1 for detection of viability was 94.8% and its specificity was 91.7%, while the sensitivity using SW2 for detection of viability was 87.8%, and its specificity was 81.5%. Conclusion The presystolic wave during DSTDE showed a greater sensitivity and specificity for the prediction of myocardial viability than the systolic wave.