Hydroxyapatite-Hardystonite nanocomposite scaffolds prepared by the replacing the polyurethane polymeric sponge technique for tissue engineering applications

Objective (s): Silicate bioceramics containing Zn and Ca like hardystonite (Hr) with chemical formula Ca2ZnSi2O7 has attracted the attention of researchers in biomedical field due to its remarkable biological and mechanical properties. The new generation of bioceramics can applied in bone tissue engineering to substitute with infected bone. However, these zirconium-silicate bioceramics have proper features; they can be used as additive with calcium phosphates (CaPs) like hydroxyapatite (HA). These composite may enhance the weak properties of pure HA powders. Materials and Methods: In the current study, the Hr powder with sol-gel method was synthesized. Then, hydroxyapatite-hardystonite (HA/Hr) scaffolds with various amount of Hr in HA (0, 5, 10, and 15 wt. % )  were prepared by the replacing the polyurethane polymeric sponge technique. Then, the ceramic scaffolds were sintered at 1150ºC for 3 hours. The result of the scaffold nanocomposite specimens were tested for compressive strength and bioactivity behaviour. The phase and morphology of the specimens were analysis with X-ray Diffraction (XRD) and Scan Electron Microscope (SEM) techniques. Results: The bioactivity, sinterability and compressive strength (CS) properties of HA-Hr scaffold nanocomposite has been developed by addition of 15 wt. % Hr in HA matrix. The results showed the scaffold nanocomposite containing 15 wt. % Hr have the highest value of CS which is equal 1.21 MPa. Our data indicate that Hr ceramics possess proper mechanical properties as compared to pure HA, and may possess good biocompatibility in biological analysis. Conclusion: The study indicates that scaffold containing 10 wt. % Hr had proper bioactivity behaviour which leads the scaffolds surface to form bone-like apatite on the surface of scaffolds

Relationship between Body Mass Index and Outcome of Elective Percutaneous Coronary Intervention

Background: Studies have shown controversial effects of obesity on major adverse cardiac events (MACE) after percutaneous coronary intervention (PCI). We sought to investigate the impact of the body mass index (BMI) on the mid-term outcome following successful PCI. Methods: Between March 2006 and August 2008, 3948 patients underwent successful elective PCI in Tehran Heart Center, Tehran, Iran, and were retrospectively included in this study. Patients who underwent PCI on the same day as the occurrence of myocardial infarction were excluded. The demographic, procedural, in-hospital, and follow-up information of these patients was extracted from the PCI Data Registry of our institution. The patients were divided into three groups:  normal weight (No. 1058, BMI < 25 kg/m2 age = 58 ± 10 years); overweight (No. 1867, 25 ≤ BMI < 30 kg/m2, age = 57 ± 10 years); and obese (No. 1023, BMI ≥ 30 kg/m2, age = 56 ± 10 years). MACE included death, myocardial infarction, target vessel revascularization, and target lesion revascularization. Results: Compared with the other patients, the obese individuals were significantly younger and more frequently female, had a higher ejection fraction, and more frequently presented with hypertension, diabetes, and hyperlipidemia. There was no association between the BMI and the angiographic and procedural findings in the univariate analysis. While no difference was found in the rate of in-hospital death between the groups, the number of the obese patients undergoing emergent cardiac surgery was marginally different in the univariate analysis (p value = 0.06). At 9 months' follow-up, MACE had occurred in 92 (2.3%) patients and cardiac mortality was 9 (0.2%). After adjustments for confounders, no significant difference was observed in terms of MACE between the BMI groups. Conclusion: The BMI had no significant effect on the rate of MACE at 9 months' follow-up in our study population. Interventionists' recommendations for patients undergoing PCI should, therefore, not be significantly influenced by the BMI status

Predictors of major adverse cardiac events following elective stenting of large coronary arteries

Objective: Diameter of the affected coronary artery is an important predictor of restenosis and need for revascularization. In the present study, we investigated the frequency and potential risk factors for major adverse cardiac events following elective percutaneous coronary intervention (PCI) and stenting of large coronary arteries. Methods: We reviewed the data of elective candidates of PCI on a large coronary artery who presented to our center. Demographic, clinical, angiographic and follow-up data of the eligible patients were retrieved from our databank. The study characteristics were then compared between the patients with and without MACE in order to find out the probable risk factors for MACE in patients with large stent diameter. Results: Data of 3043 patients who underwent single vessel elective PCI with a stent diameter of ≥3.5 mm was reviewed. During a median follow up period of 14 months, 64 (2.1%) patients had MACE. TVR was the most common type of MACE that was observed in 29 patients, while 5 patients had cardiac death. Higher serum levels of creatinine, history of cerebrovascular accident (CVA), and use of a drug eluting stent (DES) were significantly associated with MACE. In the multivariate model, history of CVA (odds ratio = 5.23, P = 0.030) and use of DES (odds ratio = 0.048, P = 0.011) were the independent predictors of MACE in patients underwent large coronary artery stenting. Conclusion: This study showed that prior CVA and the use of BMS were the potential risk factors for MACE in patients who were stented on their large coronary arteries

Effectiveness of Two-Year Versus One-Year Use of Dual Antiplatelet Therapy in Reducing the Risk of Very Late Stent Thrombosis After Drug-Eluting Stent Implantation

Background: Impact of 12 months’ versus 24 months’ use of dual antiplatelet therapy on the prevalence of stent thrombosis in patients undergoing percutaneous coronary intervention (PCI) with the drug-eluting stent (DES) is not clear. As a result, duration of dual antiplatelet therapy is still under debate among interventionists. Methods: From March 2007 until August 2008, all consecutive patients with successful PCI who received at least one DES and were treated with dual antiplatelet therapy (Clopidogrel + Aspirin) were included. All the patients were followed up for more than 24 months (mean = 35.27 ± 6.91 months) and surveyed for very late stent thrombosis and major cardiovascular events.Results: From 961 patients eligible for the study, 399 (42%) discontinued Clopidogrel after 12 months and 562 (58%) continued Clopidogrel for 24 months. The clinical and procedural variables were compared between the two groups. In the 12 months’ use group, two cases of definite thrombosis occurred at 18 and 13 months post PCI. In the 24 months’ use group, 2 cases of definite thrombosis occurred at 14 and 28 months post PCI, one of them with stenting in a bifurcation lesion. Five cases of probable stent thrombosis were detected at 21, 28, 32, 33, and 34 months after the procedure. It is of note that amongst the 10 cases of stent thrombosis, only 1(10%) thrombosis occurred when the patient was on Clopidogrel and Aspirin and all the other 9 (90%) cases of thrombosis appeared after the discontinuation of the dual antiplatelet therapy. Conclusion: Extended use of dual antiplatelet therapy (for more than 12 months) was not significantly more effective than Aspirin monotherapy in reducing the risk of myocardial infarction or stent thrombosis, death from cardiac cause, and stroke

A Risk-Scoring Model to Predict One-year Major Adverse Cardiac Events after Percutaneous Coronary Intervention

Background: The aim of the present study was to develop a scoring system for predicting 1-year major adverse cardiac events (MACE), including mortality, target vessel or target lesion revascularization, coronary artery bypass graft surgery, and non-fatal myocardial infarction after percutaneous coronary intervention (PCI). Methods: The data were extracted from a single center PCI registry. The score was created based on the clinical, procedural, and laboratory characteristics of 8206 patients who underwent PCI between April 2004 and October 2009. Consecutive patients undergoing PCI between November 2009 and February 2011 (n= 2875) were included as a validation data set. Results: Diabetes mellitus, increase in the creatinine level, decrease in the left ventricular ejection fraction, presentation with the acute coronary syndrome, number of diseased vessels, primary PCI, PCI on the left anterior descending artery and saphenous vein graft, and stent type and diameter were identified as the predictors of the outcome and used to develop the score (R² = 0.795). The models had adequate goodness of fit (Hosmer-Lemeshow statistic; p value = 0.601) and acceptable ability of discrimination (c-statistics = 0.63). The score categorized the individual patients as low-, moderate-, and high-risk for the occurrence of MACE. The validation of the model indicated a good agreement between the observed and expected risks. Conclusion: An individual risk-scoring system based on both clinical and procedural variables can be used conveniently to predict 1-year MACE after PCI. Risk classification based on this score can assist physicians in decision-making and postprocedural health care.

Opium Consumption and Mid-Term Outcome of Percutaneous Coronary Intervention in Men

Background: Controversy persists over the potential benefits/harms of opium consumption in coronary heart disease. This study investigated the association between 12 months' major adverse cardiac events (MACE) and pre-procedural opium consumption among patients undergoing percutaneous coronary intervention (PCI). Methods: Retrospectively, 1545 consecutive men who underwent PCI between 21st  June 2009 and 20th June 2010 at Tehran Heart Center and were registered in the PCI Databank were entered into this cohort study. The occurrence of MACE, defined as cardiac death, non-fatal myocardial infarction, and need for target vessel revascularization (TVR) or target lesion revascularization (TLR), was compared between two groups of opium consumers and non-consumers in 350 (22.7%) patients. Results: Sixty-four (0.86%) patients expired within 12 months. After adjustment for potential confounders, analysis revealed that opium consumption had no significant relationship with 12 months' MACE [11(3.1%) vs. 53(4.4%); p value= 0.286, among opium users vs. non users, respectively].Furthermore, the different components of MACE, including target vessel revascularization, target lesion revascularization, coronary artery bypass graft, and non-fatal myocardial infarction, were not significantly related to opium use. Conclusion: Pre-procedural opium usage in patients undergoing PCI was not associated with 12 months' MACE