Ahmed Shawky Elserafy

Trimetazidine in the prevention of contrast-induced nephropathy in chronic kidney disease

BACKGROUND Contrast induced nephropathy (CIN) may be defined as Acute Renal Failure (ARF) that occurs within 24-72h of exposure to intra-venous or intra-arterial iodinated contrast media that cannot be attributed to other causes. CIN occurs in up to 5% of hospitalized patients with normal renal function prior to injection of contrast media. It occurs more frequently in patients with renal impairment particularly if associated with diabetic nephropathy. Among all procedures utilizing contrast agents for either diagnostic or therapeutic purposes, coronary angiography and percutaneous coronary interventions are associated with the highest rates of CIN. Trimetazidine has been described as a cellular anti-ischemic agent. Previous studies demonstrated that Trimetazidine prevents the deleterious effects of ischemia-reperfusion at both the cellular and mitochondrial levels and exerts an anti-oxidant effect. It inhibits excess release of oxygen free radicals, limits cellular acidosis, protects Adenosine Triphosphate (ATP) stores, reduces membrane lipid peroxidation and inhibits neutrophil infiltration. AIM To evaluate the role of Trimetazidine (TMZ) in prevention of contrast induced nephropathy (CIN) in patients with renal impairment undergoing coronary angiography. METHODS AND RESULTS This study was conducted on one hundred patients having a basal creatinine clearance below 90ml/min and presenting for coronary angiography procedures. The patients were divided into two equal groups each including fifty patients where both groups received parenteral hydration in the form of isotonic saline at a rate of 1mg/kg body weight per hour starting 12h before angiography and up to 12h thereafter. In Group 1, patients received additional medication in the form of trimetazidine 35mg twice daily for 72h and starting 48h before the procedure which was not received in group 2 (control). There was a significant difference regarding the rate of CIN among TMZ versus control groups (10% vs. 26%). The amount of contrast was significantly higher in the CIN group (165.00±108.41 vs 89.85±38.60, P=0.000). CONCLUSION Administration of trimetazidine in a dose of 35mg twice daily orally in conjunction with standard early saline hydration is an effective method to prevent or reduce the incidence of contrast-induced renal dysfunction following the administration of contrast media during coronary angiography procedures in patients with mild-moderate basal renal insufficiency.

Effect of chronic pretreatment with beta-blockers on no-reflow phenomenon in diabetic patients with acute ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention

Background No-reflow is an important factor as it predicts a poor outcome in patients undergoing primary angioplasty. In comparison with patients attaining TIMI 3 flow, patients with no-reflow have an increased incidence of ventricular arrhythmias, early congestive cardiac failure, cardiac rupture and cardiac death. As such, it is of paramount importance to consider strategies to prevent the occurrence of no-reflow phenomenon. Previous evidence suggests that Beta (β) blockers have multiple favorable effects on the vascular system not directly related to their effect on blood pressure. However, there are insufficient data regarding the effects of prior Beta blocker use on coronary blood flow after primary PCI in patients with AMI. Aim The aim of this study was to test the hypothesis that Beta blocker treatment before admission would have beneficial effects on the development of the no-reflow phenomenon after acute myocardial infarction. Methods and results The study included 107 diabetic patients who had presented with acute STEMI within 12 h from the onset of chest pain. All of them have undergone primary angioplasty at Ain Shams University hospitals or National Heart institute. The incidence of no-reflow phenomenon was 21%. No-reflow phenomenon was significantly lower in patients on chronic B-blocker therapy (12% vs. 28%; P = 0.04). The heart rate was significantly lower in the normal reflow group than in the no-reflow group (P = 0.03). The study also showed that B-blocker pretreatment is an independent protective predictor for the no-reflow phenomenon (P = 0.045). Conclusion Chronic pre-treatment with B-blocker in diabetic patients presenting with STEMI, is associated with lower rate of occurrence of no-reflow phenomenon after primary PCI.

Enhanced Genetic Algorithm for MC/DC test data generation

Structural testing is concerned with the internal structures of the written software. The targeted structural coverage criteria are usually based on the criticality of the application. Modified Condition/Decision Coverage (MC/DC) is a structural coverage criterion that was introduced to the industry by NASA. Also, MC/DC comes either highly recommended or mandated by multiple standards, including ISO 26262 from the automotive industry and DO-178C from the aviation industry due to its efficiency in bug finding while maintaining a compact test suite. However, due to its complexity, huge amount of resources are dedicated to fulfilling it. Hence, automation efforts were directed to generate test data that satisfy MC/DC. Genetic Algorithms (GA) in particular showed promising results in achieving high coverage percentages. Our results show that coverage levels could be further improved using a batch of enhancements applied on the GA search.

Right ventricular function in patients presenting with non-ST-segment elevation myocardial infarction undergoing an invasive approach

Background Right ventricular involvement in ST segment elevation myocardial infarction (STEMI) entails an increased morbidity and mortality. However, very scarce data is present on its affection in the setting of non-ST segment elevation myocardial infarction (NSTEMI). Aim To assess the affection of right ventricular function in patients presenting with NSTEMI undergoing an invasive procedure. Subjects and methods One hundred and fifty patients admitted with a first NSTEMI and eligible for reperfusion therapy via invasive percutaneous coronary intervention. These patients were divided in two groups; group A including patients with normal RV function, and group B including patients with impaired RV function as diagnosed by tricuspid annular plane systolic excursion (TAPSE) cutoff value < 17 mm. All patients underwent angioplasty and were followed up in-hospital and for 3 months. Results RV dysfunction occurred in ninety-five (61.3%) patients of the study population. Significant improvement occurred to TAPSE after 3 months in comparison to TAPSE at baseline (15.45 ± 3.21 versus 17.09 ± 4.17 mm). Those with impaired RV function showed improvement of TAPSE after three months as compared to baseline (13.62 ± 2.58 vs 17.16 ± 3.64 p = 0.008). Multivariate analysis determined the independent predictors of RV dysfunction as RVEDD > 26 mm, RVFAC < 35%, RAA > 20 cm2, and TAPSE < 17 mm. Conclusion RV dysfunction is not uncommon in NSTEMI when using the definition of TAPSE < 17 mm. Following up RV function by TAPSE, showed significant improvement after 3 months with successful PCI as compared to baseline. We recommend assessing and following up RV function in all patients admitted with a NSTEMI.

Prevention of contrast induced nephropathy by ischemic preconditioning in patients undergoing percutaneous coronary angiography

Background Contrast-induced nephropathy (CIN) is the acute deterioration of renal function after parenteral administration of radio contrast media in the absence of other causes. The true incidence of CIN varies because of differences among the published studies in the definition of CIN, the proportion of high-risk patients, the types of contrast media, and the use of preventive measures. Remote ischemic preconditioning (IPC) may offer a non-pharmacological prevention strategy for lowering CIN in patients undergoing coronary procedures. The assumption that IPC produces protective effects on tissues or organs by multiple brief cycles of ischemia and reperfusion applied to another remote tissue or organ. Aim To investigate the effect of ischemic preconditioning in prevention of CIN in patients with renal impairment undergoing percutaneous coronary angiography. Results In this study, 100 patients undergoing elective PCI with a base line creatinine clearance <60 ml/min were studied. Patients were divided into two equal groups (ischemic preconditioning group and control group). The incidence of CIN was markedly lower in ischemic preconditioning group 14% VS 38% in control group. The incidence of CIN difference as was found to be (24%). Amount of dye used, decreased LVEF and presence of a significant LAD lesion were significant risk factors for occurrence of CIN. Conclusions The current study showed that remote ischemic preconditioning plays an important role in prevention of CIN in patients undergoing PCI with renal impairment GFR < 60 ml/min. The amount of contrast, decreased LVEF, and presence of LAD significant lesion were significant risk factors for developing of CIN and these subgroups benefited from application of ischemic preconditioning.

Automatic Test Data Generation Targeting Hybrid Coverage Criteria

Software used in safety critical domains such as aviation and automotive has to be rigorously tested. Since exhaustive testing is not feasible, Modified Condition/Decision Coverage (MC/DC) has been introduced as an effective structural coverage alternative. However, studies have shown that complementing the test cases satisfying MC/DC to also satisfy Boundary Value Analysis (BVA) increases the bug finding rate. Hence, the industry adopted its testing processes to accommodate both. Satisfying these coverage requirements manually is very expensive and as a result many efforts were put to automate this task. Genetic algorithms (GA) have shown their effectiveness so far in this area. We propose an approach employing GA techniques and targeting hybrid coverage criteria to increase BVA in addition to MC/DC.