Using tissue mitral valves in younger patients: A word of caution.

BACKGROUND: The debate about the optimal mitral valve prosthesis continues. We aimed to compare the early and late outcomes, including stroke, bleeding, survival, and reoperation after isolated mitral valve replacement (MVR) using tissue versus mechanical valves. METHODS: This retrospective cohort study included 291 patients who had isolated MVR from 2005 to 2015. Patients were grouped into the tissue valve group (n = 140) and the mechanical valve group (n = 151). RESULTS: There were no differences in duration of mechanical ventilation, hospital stay, and hospital mortality between groups. Fifteen patients required cardiac rehospitalization, nine in the tissue valve group, and six in the mechanical valve group (p = .44). Stroke occurred in nine patients, five with tissue valves, and four with mechanical valves (p = .66). Bleeding occurred in 22 patients, seven patients with tissue valves, and 15 patients with mechanical valves (p = .09). Freedom from reoperation was 95%, 93%, 84%, 67% at 3, 5, 7, and 10 years for tissue valve and 97%, 96%, 96%, and 93% for mechanical valves, respectively (p˂ .001). The median follow-up was 84 months (Q1: Q3: 38-139). Survival at 3, 5, 7, and 10 years was 94%, 91%, 89%, 86% in tissue valves and 96%, 93%, 91%, 91% in mechanical valves, respectively (p = .49). CONCLUSIONS: Tissue valve degeneration is still an issue even in the new generations of mitral tissue valves. The significant risk of reoperation in patients with mitral tissue valves should be considered when using those valves in younger patients. Mechanical valves remain a valid option for all age groups.

Population Pharmacokinetic Model for Vancomycin Used in Open Heart Surgery: Model-Based Evaluation of Standard Dosing Regimens.

The purpose of this study was to investigate the population pharmacokinetics of vancomycin in patients undergoing open heart surgery. In this observational pharmacokinetic study, multiple blood samples were drawn over a 48-h period of intravenous vancomycin in patients who were undergoing open heart surgery. Blood samples were analyzed using an Architect i4000SR immunoassay analyzer. Population pharmacokinetic models were developed using Monolix 4.4 software. Pharmacokinetic-pharmacodynamic (PK-PD) simulations were performed to explore the ability of different dosage regimens to achieve the pharmacodynamic targets. A total of 168 blood samples were analyzed from 28 patients. The pharmacokinetics of vancomycin are best described by a two-compartment model with between-subject variability in clearance (CL), the volume of distribution of the central compartment (V1), and volume of distribution of the peripheral compartment (V2). The CL and the V1 of vancomycin were related to creatinine CL (CLCR), body weight, and albumin concentration. Dosing simulations showed that standard dosing regimens of 1 and 1.5 g failed to achieve the PK-PD target of AUC0-24/MIC > 400 for an MIC of 1 mg/liter, while high weight-based dosing regimens were able to achieve the PK-PD target. In summary, the administration of standard doses of 1 and 1.5 g of vancomycin two times daily provided inadequate antibiotic prophylaxis in patients undergoing open heart surgery. The same findings were obtained when 15- and 20-mg/kg doses of vancomycin were administered. Achieving the PK-PD target required higher doses (25 and 30 mg/kg) of vancomycin.

Population Pharmacokinetic Model-Based Evaluation of Standard Dosing Regimens for Cefuroxime Used in Coronary Artery Bypass Graft Surgery with Cardiopulmonary Bypass.

The purpose of this study was to investigate the population pharmacokinetics (PK) of cefuroxime in patients undergoing coronary artery bypass graft (CABG) surgery. In this observational pharmacokinetic study, multiple blood samples were collected over a 48-h interval of intravenous cefuroxime administration. The samples were analyzed by using a validated high-performance liquid chromatography (HPLC) method. Population pharmacokinetic models were developed using Monolix (version 4.4) software. Pharmacokinetic-pharmacodynamic (PD) simulations were performed to explore the ability of different dosage regimens to achieve the pharmacodynamic targets. A total of 468 blood samples from 78 patients were analyzed. The PK for cefuroxime were best described by a two-compartment model with between-subject variability on clearance, the volume of distribution of the central compartment, and the volume of distribution of the peripheral compartment. The clearance of cefuroxime was related to creatinine clearance (CLCR). Dosing simulations showed that standard dosing regimens of 1.5 g could achieve the PK-PD target of the percentage of the time that the free concentration is maintained above the MIC during a dosing interval (fTMIC) of 65% for an MIC of 8 mg/liter in patients with a CLCR of 30, 60, or 90 ml/min, whereas this dosing regimen failed to achieve the PK-PD target in patients with a CLCR of ≥125 ml/min. In conclusion, administration of standard doses of 1.5 g three times daily provided adequate antibiotic prophylaxis in patients undergoing CABG surgery. Lower doses failed to achieve the PK-PD target. Patients with high CLCR values required either higher doses or shorter intervals of cefuroxime dosing. On the other hand, lower doses (1 g three times daily) produced adequate target attainment for patients with low CLCR values (≤30 ml/min).

Laparoscopic extraction of a migrated pacemaker in a 6-year-old child: A case report.

The laparoscopic approach can provide a safe option with good results for extracting an uncomplicated migrated pacemaker in children.

Serum level of prophylactic antibiotics in cardiac surgery and its implication on surgical site infection (SSI).

BACKGROUND: Surgical site infection in cardiac surgery is still common despite applying preoperative antibiotic prophylaxis as per guidelines. Therefore, the aim of our study was to assess the relationship between perioperative antibiotics serum levels and the incidence of surgical site infection. METHODS: This is a prospective study that included all adult patients who underwent elective coronary artery bypass grafting between June and December 2018. The serum antibiotics levels were measured at 4 different time points. The patients were divided into two groups: The group who developed surgical site infection and the group who did not develop surgical site infection. The serum antibiotics levels were compared between the two groups. RESULTS: Eighty-seven consecutive patients were enrolled in the study. The overall rate of infection was 17.95% (14/78 patients). High pre-operative HbA1C levels were associated with a higher rate of SSI (SSI 8.46 ± 2.23 vs no SSI 7.28 ± 1.82, P = 0.04). Patients who developed surgical site infection had longer intervals between administration of prophylactic antibiotics and different parts of the procedure than those who did not develop infection T2 (SSI 3.09 ± 1.12 vs no SSI 2.32 ± 0.98, P = 0.004), T3 (SSI 5.74 ± 1.69 vs no SSI 4.68 ± 1.83, P = 0.024) and T4 (SSI 7.35 ± 1.97 vs no SSI 6.01 ± 2.11, P = 0.015). CONCLUSION: Prolonging different parts of cardiac surgery procedures could lead to higher risk of infection and better timing of intra-operative re-dosing of prophylactic antibiotics could be guided by measuring intra-operative serum concentrations of these antibiotics.