Surgical repair of post myocardial infarction ventricular septal defect: a retrospective analysis of a single institution experience.

INTRODUCTION: Ventricular septal defect (VSD) is a mechanical complication of acute myocardial infarction (MI) with a very high mortality, despite advances in surgical and circulatory support. The tremendous hemodynamic disturbance and the severely fragile myocardium render surgical repair a great challenge. The optimal time of surgical repair with or without circulatory support is still controversial. OBJECTIVE: The aim of this study is to review our experience with early surgical repair of post-MI VSD in a single major cardiac institution in China. METHODS: From January 2013 to October 2020, 9consecutive patients presented to our emergency department with a diagnosis of post-MI VSD. Among them, 8 were male, and the mean age was 58 ± 7years. The mean VSD size was 22.5 ± 5.7 mm. In all patients, an intra-aortic balloon pump (IABP)was inserted immediately after admission to cardiac surgery service. All patients were operated at a mean of 3.3 ± 2.9 days, and 4 within 24 h of the rupture (range 1 to 9 days post-VSD). In 5 cases, the VSD was located superiorly, and 4 cases in the posterior septum. RESULTS: The overall 30-day mortality was 11% (1/9). Coronary angiography was performed in all nine patients, four with single vessel disease had coronary stents implanted, and the other five received concomitant coronary artery bypass grafting during VSD repair surgery. There was no death in all 5 patients with anterior septal perforation. One patient with posterior septal perforation died in the operating room due to bleeding from the ventriculotomy site. Three survived patients were diagnosed with a small residual defect and mild left to right shunt post-repair. However, no further intervention was required, and patients remained asymptomatic (Killip II in 1 and III in 2). CONCLUSION: In our experience, immediate insertion of IABP and hemodynamic stabilization with early surgical intervention of VSD repair and concomitant coronary revascularization provided an 89% survival rate.

Incidence of readmission to the ICU after cardiac surgery: a systematic review and meta-analysis.

Background: Due to the complexity of cardiac surgery, almost all patients need to be admitted to the intensive care unit (ICU) for postoperative care after surgery. After being discharged from the ICU, some patients need to be readmitted due to disease deterioration during hospitalization. We conducted a meta-analysis of the literature to investigate the incidence of readmission to the ICU in patients undergoing cardiac surgery. Methods: The PubMed, Medline, and Elsevier databases were searched using the keywords "cardiac surgery," "readmission," "intensive care unit," and "ICU" to retrieve English-language articles published from January 2000 to January 2021. The articles were screened, and their quality was evaluated. A meta-analysis was performed on the outcomes of patients after readmission to the ICU using Stata16.0 software. Results: Ultimately, 9 articles were included in the meta-analysis, comprising 32,825 cardiac surgery cases, of whom 1,302 were readmitted to the ICU. The incidence of readmission to the ICU was 3.97%. Among the direct reasons for readmission to the ICU, respiratory failure accounted for 13.6-48.6%, while hemodynamic instability accounted for 21.6-51.9%. The results of the meta-analysis showed that the mortality rate of patients readmitted to the ICU was significantly higher than that of patients not readmitted to the ICU [risk difference (RD) =8.05, 95% confidence interval (CI): 5.10-12.69, Z=8.965; P<0.0001], as was the length of hospital stay [standard mean difference (SMD) =3.17, 95% CI: 1.40-4.94, Z=3.504; P<0.001], and the incidence of complications (odds ratio =1.97, 95% CI: 1.35-2.87, Z=3.507; P<0.001). Conclusions: Nine articles were included in this meta-analysis on the incidence rate of readmission to the ICU of patients undergoing cardiac surgery. The results showed that the proportion of readmission to the ICU was 3.97%. Patients readmitted to the ICU had a higher rate of complications, longer hospital stay, and higher mortality rate than those not readmitted.

An Amplitude- and Temperature-Dependent Vibration Model of Fiber-Reinforced Composite Thin Plates in a Thermal Environment.

A thermal environment has a complex influence on the dynamic characteristics of fiber-reinforced composite materials and structures. It is challenging to consider the effects of high temperature and external vibration energy simultaneously on their nonlinear vibration response. In this research, the material nonlinearities, due to both the excitation amplitudes and the high temperatures, are studied for the first time, and a new nonlinear vibration model of fiber-reinforced composite thin plates in a thermal environment is proposed by introducing the nonlinear thermal and amplitude fitting coefficients simultaneously. Then, based on the classical laminated plate theory, the complex modulus approach, and the power function and the Ritz methods, dynamic governing equations in high-temperature environments are derived to solve the nonlinear natural frequencies and vibration responses and damping parameters. Moreover, the three-dimensional fitting curves of the elastic moduli and loss factors, excitation amplitudes, and temperature values are obtained so that the key nonlinear fitting coefficients in the amplitude- and temperature-dependent model can be identified. To validate this model, the experimental tests on CF130 carbon/epoxy composite thin plates are undertaken. It is found that the 3rd and 5th natural frequencies, vibration responses, and damping results obtained from the nonlinear model are consistent with the experimental measurements, and the mechanism of nonlinear thermal vibration behaviour is revealed.