Guest author of this article

Dong Nanguo, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, China

The nationally reported rate of nonstenotic mitral valve repair ranges from 75% to 84%. However, existing risk models and subset analyses for mitral valve surgery are based on surgical data from 2011 to 2016.2023 In a joint article in the February 8, 2023, issue of The Annals of Thoracic Surgery and the Journal of the American College of Cardiology, cardiology and cardiac Thoracic Surgery researchers analyzed recent large-scale clinical data to assess the risk of mitral valve repair for the treatment of primary MR. The data used in the evaluation came from 53,462 patients who underwent mitral valve repair for primary MR between 2014 and 2020 from the Society of Thoracic Surgeons Adult Cardiac Surgery Database. The study found a low risk of death from mitral valve repair across nearly all age ranges. Based on these clinical data, the researchers developed the new Mitral Valve Repair Surgery Risk Assessment Model, a new risk model that evaluates current outcomes and the risk of mitral valve repair in primary MR with complete information from national registry data (including MR etiology, MR mechanism, and surgical details) from the STS ACSD, thus providing favorable support for clinical decision-making.

The indications for surgery in patients with degenerative mitral regurgitation (DMR) have shown a trend toward increasing leniency, but the role of secondary outcome determinants (left atrial volume index ≥60 mL/m2, atrial fibrillation, pulmonary artery systolic blood pressure ≥50 mmHg, and moderate-to-severe tricuspid regurgitation) and how they affect postoperative outcomes are unclear.2023 On January 26, the European Heart The results of a study published in the Journal suggest that the presence and number of secondary outcome determinants are independently associated with postoperative survival in patients with DMR undergoing surgical treatment.The study included 2,276 patients with DMR who underwent surgery within 1 year of enrollment in the Mitral Regurgitation International DAtabase-Quantitative Registry between January 2003 and January 2020, with a median follow-up of 5.6 years. Adjusted multivariate Cox regression models showed that the number of secondary outcome determinants was independently associated with postoperative all-cause mortality, with risk ratios of 1.56 (P = 0.011), 1.78 (P = 0.002), and 2.58 (P < 0.0001) for patients with 1, 2, 3, or 4 secondary outcome determinants, respectively. In addition, models incorporating secondary outcome determinants demonstrated a higher C-index compared with models incorporating only traditional class I indications.

Prosthetic valve-patient mismatch (PPM) affects postoperative hemodynamics after aortic valve replacement, but there is a lack of evidence-based correlation with intermediate- and long-term postoperative mortality.20 In March 2023, the JACC published the results of the SWEDEHEART Long-Term Follow-Up Study, which included 16,423 patients from the SWEDEHEART (Swedish Web system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies), which included 16,423 patients from the SWEDEHEART (Swedish Web System for Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies) study using the Valve Academic Research Consortium 3 criteria to define PPM, of which 7377 had no PPM, 8502 had moderate PPM, and 544 had severe PPM.The study found that the difference in 10-year survival between patients with no PPM and those with moderate and severe PPM was 1.7% and 4.6%, respectively and. The difference in hospitalization rates for heart failure at 10 years between patients with severe PPM and no PPM was 6.0%. The study concluded that an increase in PPM grade was associated with long-term mortality and that severe PPM was associated with heart failure. Moderate PPM was more common, but the absolute risk difference in clinical outcomes was small and of negligible clinical significance.

There is no high-quality evidence from randomized clinical trials (RCTs) that small-incision mitral valve repair has equal or better benefits than conventional sternotomy.2023 JAMA published the results of a randomized controlled trial that included 330 patients (mean age 67 years, 30% female) treated at 10 centers in the United Kingdom and randomly assigned to undergo either conventional open or small-incision mitral valve repair. open or small incision mitral valve repair. The results showed that at 12 weeks postoperatively, both groups had similar levels of recovery, and at 1 year, there were no significant differences between the two groups in secondary outcomes, including mortality, hospitalization for heart failure, repeat mitral valve surgery, adverse events (including stroke), and quality of life.

Systemic atrioventricular valve (SAVV) is a cardiac malformation often complicating patients with corrected transposition of the great arteries. Constrained by small sample sizes and short follow-up periods, the number of studies relating postoperative outcomes to risk factors has long been small.2023 In September 2023, JACC published the results of a retrospective study that included 108 patients with congenital corrected transposition of the great arteries who underwent surgery for SAVV between 1972 and 2022, and used the endpoints of death, cardiac transplantation, and implantation of ventricular assist devices as the primary indicators of various possible risk factors. as the primary indicators, and regression analysis of various possible risk factors. After analysis, the researchers found that abnormal valve development was the most important factor in SAVV regurgitation, accounting for about 76.9% of the total number of patients; death or heart transplantation within 5, 10, and 20 years accounted for 7.6% and 20.9% of the total number of patients, respectively, and that the SAVV procedure has a lower early mortality rate and better long-term outcomes in the treatment of corrected transposition of the great arteries, especially in the patients with an SVEF greater than or equal to 40%. 40% of patients with better outcomes, which is a valuable and safe treatment. 37.1%. Also based on outcome events, the researchers identified implantation of a bioprosthetic valve, advanced age of the patient, preoperative creatinine level, and severe SAVV regurgitation as risk factors for postoperative death or poor prognosis.

Type 2 diabetes (T2D) is an important co-morbidity of aortic stenosis (AS). Although many previous studies have suggested that T2D may induce cardiac pathophysiologic changes such as adverse remodeling and abnormal energy supply, there is a lack of in-depth research on how T2D affects the prognosis of aortic valve replacement.20 A prospective study published in Circulation in September 2023 explored the effect of T2D on ventricular function and myocardial metabolism before and after replacement in patients with aortic stenosis. The study recruited 30 patients with AS-T2D versus 65 patients with AS-noT2D and 30 healthy volunteers versus 30 patients with T2D without AS (T2D controls) as controls, and collected myocardial function and metabolism 6 months after the study was conducted. The results showed that after aortic valve replacement, AS patients who also had T2D persistently showed abnormalities in myocardial PCr/ATP, vasodilator-stimulated MBF, and cardiac systolic function; AS patients who did not suffer from T2D showed effective improvement in all of the above indices, and patients suffering from metabolic disorders need to be continuously monitored for a better prognosis after AVR.

Small-incision surgery is an important way to minimize the trauma of aortic valve replacement. Small-incision surgical procedures, including suprasternal versus right anterior thoracic small incisions, have shown better postoperative outcomes. However, there are no definitive comparative data between the prognosis of different types of small-incision surgery.JTCVS March 2023 compared the short- and long-term outcomes of suprasternal small incisions with those of right anterior thoracic small incisions. The study included data collected between 1999 and 2019 on 2419 patients who underwent small incision aortic valve replacement, and 986 patients were ultimately enrolled in each of the two procedures after propensity score matching. Survival analyses demonstrated lower short- and long-term mortality with the small upper sternal incision. Postoperative metrics showed that the use of a small suprasternal incision was significantly associated with improved postoperative prognosis, with significantly shorter operative times, ICU stays, and hospitalizations, and reduced postoperative complications and incision pain. The use of a small suprasternal incision during minimally invasive aortic valve replacement may be a safer and more effective treatment modality.

Early anticoagulation with warfarin is recommended in patients undergoing surgical bioprosthetic valve placement or valve repair. It is unclear whether non-vitamin K antagonist oral anticoagulants are a complete alternative to warfarin.JTCVS published in January 2023 the results of a randomized controlled study trial exploring the efficacy and safety of edoxaban in patients undergoing heart valve repair or post-bioprosthetic valve replacement. The study was conducted from December 2017 to September 2019, and patients were randomly assigned to receive edoxaban (60 mg or 30 mg once daily) or warfarin for the first 3 months after surgical bioprosthetic valve implantation or valve repair. The primary efficacy outcome was a composite of death, clinical thromboembolic events, or asymptomatic intracardiac thrombosis. The primary safety outcome was the occurrence of major bleeding. The primary efficacy outcome occurred in the 4 patients taking warfarin (3.7%) and in those not taking edoxaban (risk difference, 0.0367; 95% confidence interval 0.0720 to 0.0014; P<0.001 indicates="" noninferiority="">

International studies have reported an increase in the use of bioprosthetic valves in younger patients, but long-term prognostic data in these patients are very limited.2023 Published in JTCVS published the results of a retrospective cohort study. The study included 3,969 Australian patients with AVR between 2003 and 2018, stratified by age (18-54 years; 55-64 years), and compared valve outcomes by inverse probability of treatment-weighted cohorts. In addition, the investigators estimated hazard ratios (HRs) using weighted Cox regression models to estimate weighted cumulative incidence functions for subgroups. The results showed no difference in 10-year mortality among patients aged 55 to 64 years. However, at 10 to 15 years, mortality was higher in patients who received BV (HR, 1.56; 95% CI, 1.01-2.42); each end point did not differ in patients aged 18 to 54 years. In patients aged 55 to 64 years, 10-year reoperation rates did not differ among the different types of valves, whereas at 10 to 15 years, reoperation rates were higher in the BV group compared with MV; for patients aged 18 to 54 years, reoperation rates were higher in the BV group at any time period.

Preoperative and postoperative atrial fibrillation significantly increases the risk of adverse prognosis such as stroke and thrombosis after valve surgery, but anticoagulation regimens after bioprosthetic valve implantation in patients with atrial fibrillation have been controversial.A retrospective study published by the JTCVS in June 2023 enrolled a total of 1,743 surgical patients undergoing bioprosthetic valve replacement or repair, with comorbid atrial fibrillation, and who were discharged from the hospital receiving oral anticoagulation, and described and compared the efficacy and safety of The efficacy and safety of direct oral anticoagulation (DOAC) and warfarin after surgical bioprosthetic valve replacement or repair were described and compared.After 3 months of observation and follow-up, there were no significant differences in postoperative outcomes and safety between patients receiving warfarin and DOAC, the incidence of death, ischemic stroke, transient ischemic attack, major hemorrhage, and systemic embolism was close to the same, and there was no statistically significant difference between the two groups in terms of 30-day readmission rates. The results suggest that DOAC can be a safe and effective alternative to warfarin in the early postoperative period after valve repair or surgical bioprosthetic valve replacement, and can be a more optimal postoperative anticoagulation regimen for patients undergoing valve surgery for comorbid atrial fibrillation.

Traditional bioprosthetic valves mainly use pig aortic valves as raw material, and the implantation of pig-derived tissue will inevitably trigger a strong rejection reaction in the human body. The use of glutaraldehyde, a chemical that “kills” the active cells above the raw material, results in valve failure due to calcification, with a service life of only 10 to 15 years, and many patients have to face a second or even a third operation, which is a problem that has been plaguing the international cardiovascular field.

In the face of this problem, Professor Dong Nanguo's team at Union Hospital of Tongji Medical College, Huazhong University of Science and Technology (UHZMT), proposed for the first time in 2003 the new theory of “cellularization of biomaterials to improve durability”, i.e., cellularization of valve materials can delay/avoid bioprosthetic valve failure. After more than 20 years, the team successfully realized the world's original valve material cellularization technology and developed the first international new cellularized valve.

The team originated the proteolytic decellularization method, which can effectively reduce the immunogenicity of the valve material and preserve the extracellular matrix components. The team subverted the traditional biologic valve production process and established a new biochemical cross-linking technology system of pentagallate dextrose-PGG, obtaining valve materials with excellent biomechanical properties and fundamentally solving the world problem of calcification caused by glutaraldehyde cross-linking. The third-party biological and hemodynamic evaluation of the valve material reaches the national standard: no cytotoxicity, good blood compatibility, and no calcification.

Preclinical models of porcine pulmonary valve and sheep aortic valve replacement show that after implantation of the new cellularized valve, autologous cells will grow inside the valve material, which has the ability of tissue remodeling and repair, and is less likely to undergo calcification and decay. on May 29, 2023, the first patient with severe regurgitation of the pulmonary valve after 11 years of TOF was implanted with a new cellularized valve via pulmonary annuloplasty + right ventricular outflow tract intervention for pulmonary valve replacement. cellularized valve with good valve function on immediate postoperative ultrasound. From May 2023 to the present, 7 cases of pulmonary valve replacement, including 4 pediatric patients, have been completed in the clinical trial of the new cytochemical valve developed by Xiehe Hospital. The results of the new valve are good. The first patient's six-monthly follow-up ultrasound on December 7 showed that the right heart was smaller than before the operation, and the cardiac function was significantly improved, and the PEI-CT showed that there were cells on the surface of the valve, with a good degree of cellularization. The new cellularized valve independently developed by Xiehe Hospital is expected to realize the fundamental change of biomaterials from inert replacement to active regeneration in the future, and to promote the iterative updating of clinical application of bioprosthetic valves around the world.

The Ross procedure (autologous pulmonary valve transplantation), was developed by British heart surgeon Donald Ross in 1967. As a type of heart valve replacement, it replaces a diseased aortic valve with the patient's own pulmonary valve. Although the Ross procedure is difficult, overall its success rate has improved significantly in recent years.

The ideal procedure for younger patients requiring aortic valve replacement (AVR) remains controversial. Biologic valves are preferred in older patients, but they are prone to failure in younger patients and are associated with reoperation. In contrast, mechanical flaps offer a more durable option but require lifelong anticoagulation. In recent years, the Ross procedure has emerged as an alternative to AVR. Data suggest that the Ross procedure is associated with long-term survival after surgery compared with patients undergoing biologic or mechanical valve replacement.

On February 9, 2023, North American time, several renowned North American cardiac surgeons gave separate lectures on why the Ross procedure should be chosen for adult patients with aortic valve disease, how to improve surgical details on surgical techniques to ensure long-term prognosis, and case presentations in which the repair of the aortic valve was still preserved after reoperation in the distant future after the Ross procedure, as well as how to define an experienced Ross procedure centers were recommended with quantitative metrics.

The overall conclusions indicated that the Ross procedure would be a valuable treatment option for young patients with diastolic malformations of the aortic valve where repair does not guarantee a long-term outcome, and that the available data suggest that although bioprosthetic valves somewhat obviate the need for long-term anticoagulation, they do not improve the long-term prognosis of young patients. It remains to be seen whether this increases the risk of embolization in the distant postoperative period.

In addition, a multicenter, retrospective clinical study published in JACC by The Mount Sinai Hospital in the United States also focused on the Ross procedure versus mechanical and bioprosthetic valve replacement. The study included 1,302 patients between the ages of 18 and 50 who underwent their first elective AVR between January 1, 1997, and December 31, 2014, in California and New York. This retrospective study analyzed the different surgical approaches in terms of long-term survival and risk of valve-related complications, including stroke, major bleeding, 

reoperation, and acute endocarditis.The results of the 15-year follow-up showed that patients had significantly better survival after the Ross procedure. And compared with the Ross procedure, the overall mortality rate was more than two times higher 15 years after the procedure if the patient received a biologic or mechanical aortic valve. In addition, the actuarial survival rate after the Ross procedure was 93.1% (95% CI: 89.1%-95.7%), which is similar to that of the general U.S. population.

In terms of valve-related complications, the Ross procedure was associated with a significantly lower risk of stroke or hemorrhage compared with the mechanical valve (3.8% vs 13% ,15 years). Similarly, patients who underwent the Ross procedure had significantly fewer reoperations and fewer complications of endocarditis compared with bioprosthetic valves (17% vs 30%, 15 years). This study suggests that although there is some risk of reoperation after the Ross procedure, the associated risk is low and associated with better long-term outcomes.

Another single-center study compared the long-term outcomes of patients undergoing Ross surgery at different ages (≥ 50 years and < 50 years). The study included 225 patients who underwent Ross surgery. Both groups were predominantly male (58.5% vs 69.6%; p=0.59). The incidence of aortic valve closure insufficiency was higher in the young group (51% vs 26.1%; p<0.01), and="" the="" incidence="" of="" diastolic="" malformation="" was="" higher="">

Most domestic and international research on polymer valves is in the preclinical research stage, with little commercialization. As a cutting-edge exploration direction in the valve market, polymer valves are not only durable and biocompatible, but also do not need to be hand-sewn in the manufacturing process, which is expected to reduce production costs. As the domestic heart valve replacement and repair market continues to expand, polymer valves are expected to become a new development direction.

Nowadays, mechanical valves are no longer the mainstream of valve development, mainly because of their poor biocompatibility, easy to trigger thrombosis, for which patients have to take anticoagulants for life. The side effects of anticoagulants are so severe that some patients die from them. Therefore, with the rise of biologic valves, mechanical valves began to gradually withdraw from the valve stage.

In December 2023, the first patient was implanted with the Triflo valve, a new mechanical valve developed by Novostia in Switzerland. This patient was part of the FIM study of the Triflo valve, a prospective, single-arm, exploratory clinical study designed to evaluate the safety of the Triflo valve and to collect data on the performance and effectiveness of the Triflo valve.The Triflo valve is a breakthrough mechanical valve made of high-performance biocompatible materials with excellent wear and fatigue resistance to withstand high cardiac cycles. It solves the biggest problem of mechanical valves - thrombus - while continuing the biggest advantage of mechanical valves - high durability. Promising for pediatric and young patients, it improves quality of life and provides a unique, durable, non-anticoagulant, noiseless heart valve.