Rheumatic aortic valve disease-when and who to repair?

Multiscale structure and function of the aortic valve apparatus

Whereas studying the aortic valve in isolation has facilitated the development of life-saving procedures and technologies, the dynamic interplay of the aortic valve and its surrounding structures is vital to preserving their function across the wide range of conditions encountered in an active lifestyle. Our view is that these structures should be viewed as an integrated functional unit, here referred to as the aortic valve apparatus (AVA). The coupling of the aortic valve and root, left ventricular outflow tract, and blood circulation is crucial for AVA's functions: unidirectional flow out of the left ventricle, coronary perfusion, reservoir function, and support of left ventricular function. In this review, we explore the multiscale biological and physical phenomena that underlie the simultaneous fulfillment of these functions. A brief overview of the tools used to investigate the AVA, such as medical imaging modalities, experimental methods, and computational modeling, specifically fluid-structure interaction (FSI) simulations, is included. Some pathologies affecting the AVA are explored, and insights are provided on treatments and interventions that aim to maintain quality of life. The concepts explained in this article support the idea of AVA being an integrated functional unit and help identify unanswered research questions. Incorporating phenomena through the molecular, micro, meso, and whole tissue scales is crucial for understanding the sophisticated normal functions and diseases of the AVA.

Making a difference: 5 years of Cardiac Surgery Intersociety Alliance (CSIA)

Informed by the almost unimaginable unmet need for cardiac surgery in the developing regions of the world, leading surgeons, cardiologists, editors in chief of the major cardiothoracic journals as well as representatives of medical industry and government convened in December 2017 to address this unacceptable disparity in access to care. The ensuing "Cape Town Declaration" constituted a clarion call to cardiac surgical societies to jointly advocate the strengthening of sustainable, local cardiac surgical capacity in the developing world. The Cardiac Surgery Intersociety Alliance (CSIA) was thus created, comprising The Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgery (AATS), the Asian Society for Cardiovascular and Thoracic Surgery (ASCVTS), the European Association for Cardio-Thoracic Surgery (EACTS) and the World Heart Federation (WHF). The guiding principle was advocacy for sustainable cardiac surgical capacity in low-income countries. As a first step, a global needs assessment confirmed rheumatic heart disease as the overwhelming pathology requiring cardiac surgery in these regions. Subsequently, CSIA published a request for proposals to support fledgling programs that could demonstrate the backing by their governments and health care institution. Out of 11 applicants, and following an evaluation of the sites, including site visits to the 3 finalists, Mozambique and Rwanda were selected as the first Pilot Sites. Subsequently, a mentorship and training agreement was completed between Mozambique and the University of Cape Town, a middle-income country with a comparable burden of rheumatic heart disease. The agreement entails regular video calls between the heart teams, targeted training across all aspects of cardiac surgery, as well as on-site presence of mentoring teams for complex cases with the strict observance of "assisting only." In Rwanda, Team Heart, a US and Rwanda-based nongovernmental organization (NGO) that has been performing cardiac surgery in Rwanda and helping to train the cardiac surgery workforce since 2008, has agreed to continue providing mentorship for the local team and to assist in the establishment of independent cardiac surgery with all that entails. This involves intermittent virtual conferences between Rwandan and US cardiologists for surgical case selection. Five years after CSIA was founded, its "Seal of Approval" for the sustainability of endorsed programs in Mozambique and Rwanda has resulted in higher case numbers, a stronger government commitment, significant upgrades of infrastructure, the nurturing of generous consumable donations by industry and the commencement of negotiations with global donors for major grants. Extending the CSIA Seal to additional deserving programs could further align the international cardiac surgical community with the principle of local cardiac surgery capacity-building in developing countries.

Making a Difference: 5 Years of Cardiac Surgery Intersociety Alliance (CSIA)

Informed by the almost unimaginable unmet need for cardiac surgery in the developing regions of the world, leading surgeons, cardiologists, editors in chief of the major cardiothoracic journals as well as representatives of medical industry and government convened in December 2017 to address this unacceptable disparity in access to care. The ensuing "Cape Town Declaration" constituted a clarion call to cardiac surgical societies to jointly advocate the strengthening of sustainable, local cardiac surgical capacity in the developing world. The Cardiac Surgery Intersociety Alliance (CSIA) was thus created, comprising The Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgery (AATS), the Asian Society for Cardiovascular and Thoracic Surgery (ASCVTS), the European Association for Cardio-Thoracic Surgery (EACTS) and the World Heart Federation (WHF). The guiding principle was advocacy for sustainable cardiac surgical capacity in low-income countries. As a first step, a global needs assessment confirmed rheumatic heart disease as the overwhelming pathology requiring cardiac surgery in these regions. Subsequently, CSIA published a request for proposals to support fledgling programs that could demonstrate the backing by their governments and health care institution. Out of 11 applicants, and following an evaluation of the sites, including site visits to the 3 finalists, Mozambique and Rwanda were selected as the first Pilot Sites. Subsequently, a mentorship and training agreement was completed between Mozambique and the University of Cape Town, a middle-income country with a comparable burden of rheumatic heart disease. The agreement entails regular video calls between the heart teams, targeted training across all aspects of cardiac surgery, as well as on-site presence of mentoring teams for complex cases with the strict observance of "assisting only." In Rwanda, Team Heart, a US and Rwanda-based non-governmental organization (NGO) that has been performing cardiac surgery in Rwanda and helping to train the cardiac surgery workforce since 2008, has agreed to continue providing mentorship for the local team and to assist in the establishment of independent cardiac surgery with all that entails. This involves intermittent virtual conferences between Rwandan and US cardiologists for surgical case selection. Five years after CSIA was founded, its "Seal of Approval" for the sustainability of endorsed programs in Mozambique and Rwanda has resulted in higher case numbers, a stronger government commitment, significant upgrades of infrastructure, the nurturing of generous consumable donations by industry and the commencement of negotiations with global donors for major grants. Extending the CSIA Seal to additional deserving programs could further align the international cardiac surgical community with the principle of local cardiac surgery capacity-building in developing countries.

Making a difference: 5 years of Cardiac Surgery Intersociety Alliance (CSIA)

Informed by the almost unimaginable unmet need for cardiac surgery in the developing regions of the world, leading surgeons, cardiologists, editors in chief of the major cardiothoracic journals as well as representatives of medical industry and government convened in December 2017 to address this unacceptable disparity in access to care. The ensuing "Cape Town Declaration" constituted a clarion call to cardiac surgical societies to jointly advocate the strengthening of sustainable, local cardiac surgical capacity in the developing world. The Cardiac Surgery Intersociety Alliance (CSIA) was thus created, comprising The Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgery (AATS), the Asian Society for Cardiovascular and Thoracic Surgery (ASCVTS), the European Association for Cardio-Thoracic Surgery (EACTS) and the World Heart Federation (WHF). The guiding principle was advocacy for sustainable cardiac surgical capacity in low-income countries. As a first step, a global needs assessment confirmed rheumatic heart disease as the overwhelming pathology requiring cardiac surgery in these regions. Subsequently, CSIA published a request for proposals to support fledgling programmes that could demonstrate the backing by their governments and health care institution. Out of 11 applicants, and following an evaluation of the sites, including site visits to the 3 finalists, Mozambique and Rwanda were selected as the first Pilot Sites. Subsequently, a mentorship and training agreement was completed between Mozambique and the University of Cape Town, a middle-income country with a comparable burden of rheumatic heart disease. The agreement entails regular video calls between the heart teams, targeted training across all aspects of cardiac surgery, as well as on-site presence of mentoring teams for complex cases with the strict observance of 'assisting only'. In Rwanda, Team Heart, a US and Rwanda-based non-governmental organization (NGO) that has been performing cardiac surgery in Rwanda and helping to train the cardiac surgery workforce since 2008, has agreed to continue providing mentorship for the local team and to assist in the establishment of independent cardiac surgery with all that entails. This involves intermittent virtual conferences between Rwandan and US cardiologists for surgical case selection. Five years after CSIA was founded, its 'Seal of Approval' for the sustainability of endorsed programmes in Mozambique and Rwanda has resulted in higher case numbers, a stronger government commitment, significant upgrades of infrastructure, the nurturing of generous consumable donations by industry and the commencement of negotiations with global donors for major grants. Extending the CSIA Seal to additional deserving programmes could further align the international cardiac surgical community with the principle of local cardiac surgery capacity-building in developing countries.

Making a difference: 5 years of Cardiac Surgery Intersociety Alliance (CSIA)

SUMMARY

Informed by the almost unimaginable unmet need for cardiac surgery in the developing regions of the world, leading surgeons, cardiologists, editors in chief of the major cardiothoracic journals as well as representatives of medical industry and government convened in December 2017 to address this unacceptable disparity in access to care. The ensuing "Cape Town Declaration" constituted a clarion call to cardiac surgical societies to jointly advocate the strengthening of sustainable, local cardiac surgical capacity in the developing world. The Cardiac Surgery Intersociety Alliance (CSIA) was thus created, comprising The Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgery (AATS), the Asian Society for Cardiovascular and Thoracic Surgery (ASCVTS), the European Association for Cardio-Thoracic Surgery (EACTS) and the World Heart Federation (WHF). The guiding principle was advocacy for sustainable cardiac surgical capacity in low-income countries. As a first step, a global needs assessment confirmed rheumatic heart disease as the overwhelming pathology requiring cardiac surgery in these regions. Subsequently, CSIA published a request for proposals to support fledgling programmes that could demonstrate the backing by their governments and health care institution. Out of 11 applicants, and following an evaluation of the sites, including site visits to the 3 finalists, Mozambique and Rwanda were selected as the first Pilot Sites. Subsequently, a mentorship and training agreement was completed between Mozambique and the University of Cape Town, a middle-income country with a comparable burden of rheumatic heart disease. The agreement entails regular video calls between the heart teams, targeted training across all aspects of cardiac surgery, as well as on-site presence of mentoring teams for complex cases with the strict observance of 'assisting only'. In Rwanda, Team Heart, a US and Rwanda-based non-governmental organization (NGO) that has been performing cardiac surgery in Rwanda and helping to train the cardiac surgery workforce since 2008, has agreed to continue providing mentorship for the local team and to assist in the establishment of independent cardiac surgery with all that entails. This involves intermittent virtual conferences between Rwandan and US cardiologists for surgical case selection. Five years after CSIA was founded, it's 'Seal of Approval' for the sustainability of endorsed programmes in Mozambique and Rwanda has resulted in higher case numbers, a stronger government commitment, significant upgrades of infrastructure, the nurturing of generous consumable donations by industry and the commencement of negotiations with global donors for major grants. Extending the CSIA Seal to additional deserving programmes could further align the international cardiac surgical community with the principle of local cardiac surgery capacity-building in developing countries.

Surgical outcomes of aortic valve repair for specific aortic valve cusp characteristics; retraction, calcification, and fenestration

OBJECTIVES

We investigated the predictive value of aortic valve cusp retraction, calcification, and fenestration for aortic valvuloplasty feasibility.

METHODS

Multicenter data were collected for 2082 patients who underwent surgical aortic valvuloplasty or aortic valve replacement. The study population had retraction, calcification, or fenestration in at least one aortic valve cusp. Controls had normal or prolapsed cusps.

RESULTS

All cusp characteristics demonstrated significantly increased odds ratios [ORs] for switch to valve replacement. This effect was strongest for cusp retraction, followed by calcification and fenestration (OR, 25.14; P ≤ .001; OR, 13.50, P ≤ .001; OR, 12.32, P ≤ .001). Calcification and retraction displayed increased odds for developing grade 4 aortic regurgitation compared with grade 0 or 1 combined on average over time (OR, 6.67; P ≤ .001; OR, 4.13; P = .038). Patients with cusp retraction showed increased risk for reintervention at 1- and 2-year follow-up after aortic valvuloplasty (hazard ratio, 5.66; P ≤ .001; hazard ratio, 3.22, P = .007). Cusp fenestration was the only group showing neither an increased risk of postoperative severe aortic regurgitation (P = .57) or early reintervention (P = .88) compared with the control group.

CONCLUSIONS

Aortic valve cusp retraction, calcification, and fenestration were all related to increased rates of switch to valve replacement. Calcification and retraction were associated with recurrence of severe aortic regurgitation. Retraction was related to early reintervention. Fenestration was neither associated with recurrence of severe aortic regurgitation or reintervention. This indicates that surgeons are well able to distinguish aortic valve repair candidates in patients with cusp fenestration.

Rheumatic Heart Disease in the Developing World

Despite recent public policy initiatives, rheumatic heart disease (RHD) remains a major source of morbidity worldwide. Rheumatic heart disease occurs as a sequela of Streptococcus pyogenes (group A streptococcal [GAS]) infection in patients with genetic susceptibility. Strategies for prevention of RHD or progression of RHD include prevention of GAS infection with community initiatives, effective treatment of GAS infection, and secondary prophylaxis with intramuscular penicillin. The cardiac surgical community has attempted to improve the availability of surgery in RHD-endemic areas with some success, and operative techniques and outcomes of valve repair continue to improve, potentially offering patients a safer, more durable operation. Innovation offers hope for a more scalable solution with improved biomaterials and transcatheter delivery technology; however, cost remains a barrier.

A Review of Cardiac Surgical Procedures and Their Outcomes for Paediatric Rheumatic Heart Disease in Western Australia

INTRODUCTION

Surgical intervention is an important treatment modality for advanced rheumatic heart disease (RHD). This study aimed to describe patient characteristics and outcomes from cardiac surgery for RHD in patients referred to the only tertiary paediatric hospital in Western Australia.

METHODS

An analysis of patient characteristics and cardiac surgery outcomes in patients with RHD was undertaken, using data from clinical cardiac databases, medical notes, and correspondence from rural outreach clinics.

RESULTS

29 patients (59% female, 97% Aboriginal, Māori or Pacific Islander) underwent 41 valve interventions over 34 cardiac surgeries for RHD between 2000-2018. Median age at first surgery was 12.2 (range 4-16) years. Severe mitral regurgitation (MR) was the most common indication for primary surgery (62%), followed by mixed mitral regurgitation/aortic regurgitation (21%) and severe aortic regurgitation (17%). Mitral valve repair was the most common valve intervention (56%). Two patients had mitral valve replacement (MVR) at first operation, two patients had MVR at second operation and two had MVR at third operation. There was no early mortality. One patient required early (<30 days) reoperation for aortic valve repair failure. Two patients had late reoperations at 3.3 and 6.1 months after the first procedure for MR. Four (14%) patients experienced documented ARF recurrences. Late mortality occurred in 3 (10%) patients, all due to cardiac causes. On last follow-up echocardiogram 5 patients (17%) had moderate MR and none had severe MR.

CONCLUSIONS

This is the first study to describe characteristics and outcomes in WA paediatric patients having surgery for RHD. Outcomes are comparable to similar studies, with favourable long-term survival.

The common pathobiology between coronary artery disease and calcific aortic stenosis: Evidence and clinical implications

Calcific aortic valve stenosis (CAS), the most prevalent valvular disease worldwide, has been demonstrated to frequently occur in conjunction with coronary artery disease (CAD), the third leading cause of death worldwide. Atherosclerosis has been proven to be the main mechanism involved in CAS and CAD. Evidence also exists that obesity, diabetes, and metabolic syndrome (among others), along with specific genes involved in lipid metabolism, are important risk factors for CAS and CAD, leading to common pathological processes of atherosclerosis in both diseases. Therefore, it has been suggested that CAS could also be used as a marker of CAD. An understanding of the commonalities between the two conditions may improve therapeutic strategies for treating both CAD and CAS. This review explores the common pathogenesis and disparities between CAS and CAD, alongside their etiology. It also discusses clinical implications and provides evidence-based recommendations for the clinical management of both diseases.

Expanding Valve Repair in Rheumatic Heart Disease

Rheumatic heart disease is a serious ailment with significant morbidity and mortality in endemic areas; yet, there is no agreement on indication, timing, and surgical modality for treating rheumatic valve affection. There is mounting evidence that rheumatic mitral valve repair is possible with good long-term results, less is the case with rheumatic aortic valve disease. We discuss the surgical approach for both valves emphasizing the role of multimodality imaging.

Aortic valve repair for the treatment of rheumatic aortic valve disease: a systematic review and meta-analysis

Valvuloplasty for rheumatic aortic valve disease remains controversial. We conducted this study to explore whether aortic valvuloplasty is appropriate for the rheumatic population. A comprehensive search was conducted, and 7 eligible retrospective studies were identified from PubMed, Embase, Medline and Cochrane (up to April 7, 2020) according to the inclusion and exclusion criteria. The data for hospital mortality, 5-year survival, 5-year reoperation, aortic insufficiency grade (AIG) and aortic valve gradient (AVG) were extracted by 2 independent reviewers and were analysed to evaluate the safety and availability of aortic valvuloplasty for rheumatic patients. The heterogeneity of the results was estimated using the Q test and I² statistics. The fixed pooling model was used when I² ≤ 50%; otherwise, the random pooling model was selected. 7 articles with 418 patients were included. The pooled hospital mortality, 5-year survival and 5-year reoperation rates were 3.2%, 94.5% and 9.9%, respectively. The heterogeneities of the weighted mean differences (WMD) values of the AIG and AVG between preoperation and postoperation were extremely high (I² = 81.5%, p < 0.001 in AIG, I² = 97.6%, p = 0.003 in AVG). Subgroup analysis suggested that the AIG and AVG were improved by 3.03 grades (I² = 0%, p < 0.001) and 3.16 mmHg (I² = 0%, p < 0.001) in the European group, respectively. In the Asian group, the AIG and AVG were improved by 2.57 grades (I² = 0%, p < 0.001) and 34.39 mmHg (I² = 0%, p < 0.001), respectively. Compared with the values at discharge, the AIG was increased by 0.15 grades (I² = 0%, p = 0.031) and the AVG was still decreased by 2.07 mmHg (I² = 0%, p = 0.031) at the time of follow up. Valvuloplasty is safe and effective to treat rheumatic aortic insufficiency and stenosis, and the duration of maintenance required to improve stenosis was longer than that of insufficiency.

Early outcomes of aortic valve repair versus replacement for aortic regurgitation: a single-center experience

Background

Aortic valve repair in rheumatic patients is not well-studied. We aimed to present our initial Egyptian experience in the aortic valve repair and compare it with the aortic valve replacement. The study included 85 patients who had an aortic valve surgery for aortic regurgitation (AR) in a single center from 2018 to 2020. We assigned the patients to either aortic valve repair (n= 39) or aortic valve replacement (n= 46). Fifty-nine patients (69.4%) had rheumatic heart disease. Study outcomes were hospital complications and the degree of aortic regurgitation after 6 months in patients who had aortic valve repair.

Results

Patients who had replacement were significantly older (49.6± 7.2 vs. 43.8± 8.6 years: P= 0.002) and had more advanced New York Heart Association (P<0.001) and Canadian Cardiovascular Scoring (P= 0.03) classes. Hypertension (31 (67.4%) vs. 17 (43.6%); P= 0.03) and hypercholesteremia (18 (40%) vs. 17 (18.9%); P= 0.04) were more common in the replacement group. Patients who had replacement had a significantly higher percentage of valve retraction (P<0.001). Cardiopulmonary bypass (54.5 (49.5–60) vs. 45 (41–49) min; P<0.001) and ischemic times (36.5 (31–40) vs. 30 (28–33) min; P<0.001) were longer in patients who had an aortic valve replacement. Blood transfusion (28 (60.9%) vs. 11 (282%); P= 0.003) and ICU stay (24.5 (24–48) vs 23 (20–31) h; P= 0.01) were higher in the replacement group. Hospital mortality was non-significantly different between groups. Four patients had trivial AR (10.3%), and six had mild AR (15.4%) in the repair group. There was no difference in valve pathology or outcomes in aortic valve repair patients for degenerative versus rheumatic pathologies. After a 6-month follow-up, four patients had trivial AR (10.3%), and six patients had mild AR (15.4%) in the repair group.

Conclusions

Aortic valve repair could be an alternative to replacement in selected patients with rheumatic heart disease. Shorter cardiopulmonary bypass and ischemic times may improve repair outcomes compared to replacement.

Complex and multilevel left ventricular outflow tract obstruction: What can 3D echocardiography add?

Background

Subaortic obstruction by a membrane or systolic anterior motion of the mitral valve leaflets is usually suspected in young patients, especially if the anatomy of the aortic valve is not clearly stenotic and unexplained left ventricular hypertrophy exists in the context of high transaortic gradients.

Main body

In certain circumstances, some patients show both aortic and subaortic stenotic lesions of variable severity. Doppler echocardiography can help in grading severity in the case of single-level obstruction but not in patients with multilevel obstruction where the continuity equation is of no value. Three-dimensional (3D) echocardiography allows "en-face" visualization of each level of the aortic valve and subaortic tract; in addition, direct planimetry of the areas can be done using multiplanar reformatting.

Conclusions

Accordingly, 3D echocardiography plays a crucial role in the assessment in patients with multilevel left ventricular outflow tract obstruction as it can accurately delineate the location and size, and severity of the stenosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43044-021-00197-y.

The "Cairo Accord"- Towards the Eradication of RHD: An Update

Rheumatic heart disease (RHD) is the most common cause of acquired heart disease in children and young adults. It continues to be prevalent in many low- and middle-income countries where it causes significant morbidity and mortality. Following the 2017 Cairo conference "Rheumatic Heart Disease: from Molecules to the Global Community," experts from 21 countries formulated an approach for addressing the problem of RHD: "The Cairo Accord on Rheumatic Heart Disease." The Accord attempts to set policy priorities for the eradication of acute rheumatic fever (ARF) and RHD and builds on a recent series of policy initiatives and calls to action. We present an update on the recommendations of the Cairo Accord and discuss recent progress toward the eradication of RHD, including contributions from our own Aswan Rheumatic Heart Disease Registry (ARGI).

Management of rheumatic aortic valve disease using the Ozaki procedure with autologous pericardium: a case report

Background

Rheumatic valve disease (RVD) is the most common cause of cardiovascular death in low-middle income nations. Surgical aortic valve (AV) interventions for RVD, especially in children, have proven problematic with graft failure, relapse, and poor compliance with anticoagulation. A novel technique involving neocuspidization of the aortic annulus using autologous pericardium to construct new AV leaflets (the Ozaki procedure) has shown promising outcomes in children with congenital AV disease; however, there are no previous recorded cases using this technique in children with RVD.

Case summary

We present the case of a 15-year-old male presenting with exertional angina and dyspnoea with a background of previous rheumatic fever. Echocardiography had shown a regurgitant tricuspid AV, left ventricular dilatation with mitral valve leaflet tethering. The patient underwent the Ozaki procedure for his AV regurgitation and was discharged following an uneventful post-operative recovery. The patient had full resolution of symptoms following the procedure and remains well 3 years following his operation.

Discussion

This case highlights that good outcomes with the Ozaki procedure in RVD are possible 3-years post-operatively and should prompt future studies to evaluate the procedure as a surgical option for paediatric patients in this clinical context. Additionally, the Ozaki procedure may also provide a cost-effective surgical technique requiring minimal additional operative resources and reduced follow-up demand, which would be critical in low-resource clinical settings where RVD is prevalent.

Rheumatic heart disease: The role of global cardiac surgery

Rheumatic heart disease (RHD) remains a neglected disease of poverty. While nearly eradicated in high-income countries due to timely detection and treatment of acute rheumatic fever, RHD remains highly prevalent in low- and middle-income countries (LMICs) and among indigenous and disenfranchised populations in high-income countries. As a result, over 30 million people in the world have RHD, of which approximately 300,000 die each year despite this being a preventable and treatable disease. In LMICs, such as in Latin America, sub-Saharan Africa, and Southeast Asia, access to cardiac surgical care for RHD remains limited, impacting countries' population health and resulting economic growth. Humanitarian missions play a role in this context but can only make a difference in the long term if they succeed in training and establishing autonomous local surgical teams. This is particularly difficult because these populations are typically young and largely noncompliant to therapy, especially anticoagulation required by mechanical valve prostheses, while bioprostheses have unacceptably high degeneration rates, and valve repair requires considerable experience. Devoted and sustained leadership and local government and public health cooperation and support with the clinical medical and surgical sectors are absolutely essential. In this review, we describe historical developments in the global response to RHD with a focus on regional, international, and political commitments to address the global burden of RHD. We discuss the surgical and clinical considerations to properly manage surgical RHD patients and describe the logistical needs to strengthen cardiac centers caring for RHD patients worldwide.

Genetic and Developmental Contributors to Aortic Stenosis

Aortic stenosis (AS) remains one of the most common forms of valve disease, with significant impact on patient survival. The disease is characterized by left ventricular outflow obstruction and encompasses a series of stenotic lesions starting from the left ventricular outflow tract to the descending aorta. Obstructions may be subvalvar, valvar, or supravalvar and can be present at birth (congenital) or acquired later in life. Bicuspid aortic valve, whereby the aortic valve forms with two instead of three cusps, is the most common cause of AS in younger patients due to primary anatomic narrowing of the valve. In addition, the secondary onset of premature calcification, likely induced by altered hemodynamics, further obstructs left ventricular outflow in bicuspid aortic valve patients. In adults, degenerative AS involves progressive calcification of an anatomically normal, tricuspid aortic valve and is attributed to lifelong exposure to multifactoral risk factors and physiological wear-and-tear that negatively impacts valve structure-function relationships. AS continues to be the most frequent valvular disease that requires intervention, and aortic valve replacement is the standard treatment for patients with severe or symptomatic AS. While the positive impacts of surgical interventions are well documented, the financial burden, the potential need for repeated procedures, and operative risks are substantial. In addition, the clinical management of asymptomatic patients remains controversial. Therefore, there is a critical need to develop alternative approaches to prevent the progression of left ventricular outflow obstruction, especially in valvar lesions. This review summarizes our current understandings of AS cause; beginning with developmental origins of congenital valve disease, and leading into the multifactorial nature of AS in the adult population.

Combined Mitral and Aortic Valve Surgery: 17 Years' Experience in a Single Center

Background and objective:

It is not uncommon that patients requiring valve surgery have several simultaneous valvular dysfunctions. Combined aortic and mitral valve surgery is the most common form of double-valve surgery. The aim of this study was to analyze and present the outcomes of simultaneous aortic and mitral valve surgery in a single center in a real-life setting.

Methods:

The study population consisted of 150 patients operated in the Kuopio University Hospital from 2004 to 2020. All patients undergoing concomitant mitral and aortic valve surgery were included. Four groups were formed based on either the etiology or pathophysiology of the valvular dysfunction. The most common combination was mitral regurgitation with aortic regurgitation (n = 72, 48%), followed by mitral regurgitation with aortic stenosis (n = 37, 25%), endocarditis (n = 29, 19%), and mitral stenosis with aortic regurgitation or stenosis (n = 12, 8%). Concomitant coronary artery revascularization was performed in 37 (25%) patients and tricuspid valve repair in 26 (17%) patients.

Results:

Operative mortality was 2% and 30-day mortality was 7%. Overall survival was 86%, 78%, and 61% in 3, 5, and 10 years, respectively. Patients with endocarditis were significantly more morbid, and more often than other patients had to undergo an emergency operation. There were no significant differences between the groups in terms of early and late survival. In the overall cohort, the EuroSCORE II value, increased pulmonary artery pressure, decreased glomerular filtration, and length of the operation displayed a negative correlation with survival.

Conclusions:

Despite the challenging nature of multivalvular heart disease, surgery is a safe method of treatment with good short- and long-term outcomes.

Glutaraldehyde and 2,3-butanediol treatment of bovine pericardium for aortic valve bioprosthesis in sheep: a preliminary study

Background

Bovine pericardium can be used for cardiovascular repair surgeries, but challenges involving biocompatibility and durability remain. This study aimed to carry out pre-clinical testing of aortic valve replacement using an aortic valve prosthesis made of bovine pericardium modified with glutaraldehyde (GA) and 2,3-butanediol (BD).

Methods

The mechanical, plasma protein adsorption, platelet adhesion, collagenase digestion, and ninhydrin properties of the material (control vs. GA vs. GA + BD) were tested. All 3 tissues were implanted in rats and observed after 8 weeks under microscopy with alizarin red staining for calcification. Aortic valves made from the fully-treated material were implanted in sheep. A commercial bioprosthesis was used as control. Effectiveness and safety indicators were observed at 180 days after implantation.

Results

Compared with the control group, the GA + BD material showed higher elongation at breaking and tensile load (both P<0.05), lower plasma protein adsorption, lower platelet adhesion, lower collagenase digestion, lower ninhydrin value, and higher cross-linking (all P<0.05). After implantation in rat models, the GA + BD material showed little or no dissolution; there was no obvious calcification; and it was surrounded by a small amount of fibrosis, with peripheral capillary proliferation. After implantation in sheep models, the aortic valve leaflets of the experimental animals freely opened and closed, their surface was smooth, and no abnormal echo was observed. The echocardiographic results and hemodynamic were comparable between the two groups. All safety parameters were normal.

Conclusions

Modification of bovine pericardium with GA and BD results in a biomaterial with favorable properties for use as an aortic valve prosthesis.

A glimpse of hope: cardiac surgery in low- and middle-income countries (LMICs)

Currently, more than five times more people live in low- and middle-income countries (LMICs) than in high-income countries (HICs). As such, the downward trend in cardiac surgical needs in HICs reflects only the situation of one sixth of the world population while the vast majority living in LMICs has still no or limited access to life saving heart operations. In these countries, rheumatic heart disease (RHD) still accounts for a significant proportion of cardiac surgical needs. In low- and lower-middle income countries it remains the single most common cardiovascular disease in young adult and adolescent patients in need of heart surgery outweighing other indications such as congenital cardiac defects almost 4-fold. Compared to HICs with their predominance of calcific aortic stenosis in the elderly mitral valve surgery is required in >90% of the largely young patients with RHD in low-income countries (LICs) and still in 70% of the often middle aged patients in middle-income countries (MICs). Although recent government initiatives in LICs led to the establishment of local, independent cardiac surgical services gradually replacing fly-in missions, these centers still only cover less than 2% of the needs of their populations. In MICs, cardiac surgical needs continually grow with the emergence of degenerative diseases. As such, in spite of the concomitant growth of cardiac surgical capacity, significantly less than half the estimated patients in need have access. Capacities in LICs range from 0.5 to 7 cardiac operations/million population; 100-481/million in MICs and >1,200/million in HICs such as the USA and Germany. While a new level of awareness of the scope and magnitude of the problem has begun to emerge in LICs and the establishment of local cardiac surgical capacity has given rise to a glimpse of hope, the challenges of expanding these fledgling services to a significant proportion of the population still seem insurmountable. Challenges in MICs are on the other hand the widening gap between private cardiac medicine for the affluent few and overwhelmed public services for the many and the rural urban divide with the underappreciation of the ongoing dominance of RHD in the rural and indigent population on the other. Overshadowing all LMICs is the low level of valve-repair skills associated with insufficient cardiac surgical capacity and the unavailability of suitable replacement valves which address the young age of the patients and the difficulties of anticoagulation in a socioeconomic environment distinctly different from the elderly patients of HICs.