The 2020 ACC/AHA Guidelines for Management of Patients With Valvular Heart Disease: Highlights and Perioperative Implications

Effect of early versus late onset mitral regurgitation on left ventricular remodeling in ischemic cardiomyopathy in an animal model

BACKGROUND

Patients who survive a myocardial infarction have progressive cardiac dysfunction and ventricular remodeling. Mitral regurgitation is often diagnosed in these patients, and is a risk factor that portends poor prognosis. Whether such postinfarction mitral regurgitation magnifies adverse left ventricular remodeling is unclear, which was studied in an animal model.

METHODS

Forty-one adult rats were induced with myocardial infarction using left coronary artery ligation and assigned to 3 groups: group 1, myocardial infarction only; group 2, myocardial infarction with severe mitral regurgitation introduced after 4 weeks; and group 3, myocardial infarction with severe mitral regurgitation introduced after 10 weeks. Valve regurgitation was introduced by advancing a transapical ultrasound-guided needle into the mitral valve anterior leaflet. Animals were survived to 20 weeks from the index procedure, with biweekly cardiac ultrasound, and invasive hemodynamics and histology at termination.

RESULTS

At 20 weeks, end diastolic volume was largest in the groups with mitral regurgitation, compared with the group without the valve lesion (group 1, 760.9 ± 124.6 μL; group 2, 958.0 ± 115.1 μL; group 3, 968.3 ± 214.9 μL). Similarly, end systolic volume was larger in groups with regurgitation (group 1, 431.2 ± 152.6 μL; group 2, 533.2 ± 130.8 μL; group 3, 533.1 ± 177.5 μL). In the infarction-only group, left ventricular remodeling was maximal until 6 weeks and plateaued thereafter. In groups with mitral regurgitation, left ventricular remodeling was significantly elevated at the onset of regurgitation and persisted.

CONCLUSIONS

Mitral regurgitation is a potent driver of adverse cardiac remodeling after a myocardial infarction, irrespective of the timing of its onset.

Hybrid heart valves with VEGF-loaded zwitterionic hydrogel coating for improved anti-calcification and re-endothelialization

With the aging of the population in worldwide, valvular heart disease has become one of the most prominent life-threatening diseases in human health, and heart valve replacement surgery is one of the therapeutic methods for valvular heart disease. Currently, commercial bioprosthetic heart valves (BHVs) for clinical application are prepared with xenograft heart valves or pericardium crosslinked by glutaraldehyde. Due to the residual cell toxicity from glutaraldehyde, heterologous antigens, and immune response, there are still some drawbacks related to the limited lifespan of bioprosthetic heart valves, such as thrombosis, calcification, degeneration, and defectiveness of re-endothelialization. Therefore, the problems of calcification, defectiveness of re-endothelialization, and poor biocompatibility from the use of bioprosthetic heart valve need to be solved. In this study, hydrogel hybrid heart valves with improved anti-calcification and re-endothelialization were prepared by taking decellularized porcine heart valves as scaffolds following grafting with double bonds. Then, the anti-biofouling zwitterionic monomers 2-methacryloyloxyethyl phosphorylcholine (MPC) and vascular endothelial growth factor (VEGF) were utilized to obtain a hydrogel-coated hybrid heart valve (PEGDA-MPC-DHVs@VEGF). The results showed that fewer platelets and thrombi were observed on the surface of the PEGDA-MPC-DHVs@VEGF. Additionally, the PEGDA-MPC-DHVs@VEGF exhibited excellent collagen stability, biocompatibility and re-endothelialization potential. Moreover, less calcification deposition and a lower immune response were observed in the PEGDA-MPC-DHVs@VEGF compared to the glutaraldehyde-crosslinked DHVs (Glu-DHVs) after subcutaneous implantation in rats for 30 days. These studies demonstrated that the strategy of zwitterionic hydrogels loaded with VEGF may be an effective approach to improving the biocompatibility, anti-calcification and re-endothelialization of bioprosthetic heart valves.

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A new and promising strategy of overcoming defects of bioprosthetic heart valves.

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The zwitterionic hydrogel with VEGF is utilized to improve anti-calcification and re-endothelialization properties of heart valves.

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The hybrid heart valves with a VEGF-loaded zwitterionic hydrogel coating exhibits excellent biocompatibility.