Melissa P. Taylor and Abelardo DeAnda Jr
Multiple valve pathology may be due to primary valvular dysfunction of each valve or secondary to a disease process impacting both valves. Often when a single valve is diseased, the upstream valve can be secondarily affected due to ventricular dysfunction and poor forward flow. Pathology requiring surgical correction of more than one valve is usually due to rheumatic heart disease, degenerative heart disease, or infective endocarditis. The decision to pursue surgical intervention is based on the combination of the underlying disease pathology and the anticipated response to repair or replacement. Combination valvular procedures constitute 15-20% of all valvular surgeries with 80% representing aortic and mitral combined procedures. With the complexity of severe valvular heart disease, all patients should be evaluated by a Multidisciplinary Heart Valve Team.
Pathophysiology
Primary semilunar stenosis and atrioventricular secondary regurgitation
Aortic stenosis (AS) results in progressive obstruction of the left ventricular outflow tract (LVOT), which leads to the development of concentric hypertrophy of the LV resulting in decreased diastolic compliance and subsequently LV dilation. Common causes for AS are degenerative valve calcification, congenital abnormality of cusp anatomy, and rheumatic disease. It’s notable that AS from rheumatic disease does not occur unless the mitral is also involved.
Atrioventricular valvular regurgitation may be due to a primary process or more likely a result of changes in the ventricular morphology due to ventricular outflow obstruction. When secondarily regurgitant, the leaflets often appear thin and freely mobile. This functional regurgitation may improve alone with replacement of the semilunar valve (if the atrioventricular valve is otherwise structurally normal) or at more advanced stages may require annuloplasty, repair or replacement due to irreversible damage. Secondary mitral regurgitation in the setting of LV dysfunction usually improves with guideline-directed medical therapy for heart failure and correction of the aortic valve if the likely causative factor.
When mitral valve leaflets are thickened, chordae are shortened, and mobility is compromised, a primary valvular pathology should be considered.
Primary semilunar and atrioventricular insufficiency
Myxomatous degeneration is the most common cause for aortic regurgitation (AR) and mitral regurgitation (MR) individually and do not necessarily signify connective tissue disease. However, combined one must consider a connective tissue pathology such as Marfan’s, Ehlers-Danlos, etc. In these patients, one must also evaluate for concomitant aortic pathology. In one postmortem study, 54% of Marfan patients with aortic aneurysms had mitral insufficiency.
In the absence of annuloaortic ectasia, patients with both mitral and aortic valve regurgitation may potentially have repairs rather than replacements if the cuspal morphology is otherwise normal. Commissural plication of aortic valve has good results for central aortic insufficiency. Overall survival for combined mitral and aortic repairs is good however 35% of patients require reoperation at 10 years.
Insufficiency of both valves can also be sequelae of rheumatic heart disease and it is imperative to determine the underlying cardiac function, as symptoms may be secondary to irreversible heart failure. In response to an increased diastolic volume load, the LV dilates, which increases wall stress leading to increased oxygen demand and reduced coronary flow reserve. Timing of surgery is critical in AR since ventricular function and dilatation may never recover despite surgical intervention.
Infective endocarditis
The aortic valve is the most common heart valve affected by infective endocarditis. Rheumatic disease, congenital bicuspid valve, as well as degenerative calcific stenosis predispose the valve to infection. Due to its close relationship, the mitral valve can be secondarily infected through intracardiac fistula, abscess, as well as prolapse of infected aortic valve contacting the mitral valve creating “kissing” lesions. These kissing lesions are common and may present as anterior valve mitral leaflet pseudoaneurysms or perforations known as windsock lesions. The complexities and timing of surgery on infective endocarditis for multiple valve involvement is beyond the scope of this review chapter.
Indications for surgical intervention
Valvular disease significance is based on symptomatology and grading. Generally, symptomatic patients have an indication for intervention if the diseased valve is thought to contribute to symptoms. Normal presentation of combined mitral and aortic valve disease is earlier than isolated valvar disease. Timing usually depends on the primary problematic valve and current indications for intervention of single valve. Additional valve interventions should be considered if the future benefits including improved ventricular function outweigh risks associated with more complex procedures. Tables 64-1 to 64-3 review the severity classification of aortic and mitral valvular dysfunction.
Management of mixed valve disease should follow the guidelines for the predominant lesion. For ambiguous symptoms, use of biomarkers or invasive hemodynamics at rest or exercise should be considered as adjuncts to traditional imaging. For patients with mixed moderate aortic stenosis/aortic regurgitation who have developed left ventricular (LV) dysfunction (LV ejection fraction [LVEF] <50%), surgical aortic valve replacement (SAVR) is indicated (Class 1).
Table 64-1: Severity classification of aortic stenosis (AS)
| AVA | Mean Pressure Gradient | Peak Jet Velocity | Additional Qualifiers | |
| Mild | >1.5 cm2 | <25 mmHg | <3.0 m/s | |
| Moderate | 1.0-1.5cm2 | 25-40 mmHg | 3.0-4.0 m/s | |
| Severe | <1.0 cm2 | >40 mmHg | >4.0 m/s | |
| Stage D1 | <1.0 cm2 | >40 mmHg | >4.0 m/s | (symptomatic) |
| Stage D2 | <1.0 cm2 | >40 mmHg | >4.0 m/s | LVEF <50% |
| Stage D3 | <1.0 cm2 | >40 mmHg | >4.0 m/s | LVEF ³50% SVI <35 ml/m2 |
| Very Severe | <0.6 cm2 | >40 mmHg | ³5.0 m/s |
Table 64-2: Severity classification of aortic regurgitation (AR)
| Jet Width | Vena Con-tracta | Regurgitant volume/ fraction | Regurgitant orifice area | Angio Grade | Quali-fier | |
| Mild | <25% LVOT | <0.3 cm | <30 mL/<30% | <0.10 cm2 | 1+ | |
| Mod | 25-65% LVOT | 0.3-0.6 cm | 30-59mL/ 30-49% | 0.10-0.29cm2 | 2+ | |
| Sev | >65% LVOT | >0.6 cm | ³60mL/³50% | ³0.3cm2 | 3-4+ | |
| Stage C1 | LVEF ³55%, LVESD <50 mm | |||||
| Stage C2 | LVEF <55%, LVESD ³50 mm |
Table 64-3: Severity classification of mitral regurgitation (MR)
| Vena Contracta | Regurgitant volume/fraction | Effective regurgitant orifice | Angiographic grade | |
| Mild | <0.3 cm | <30mL | <0.2cm2 | |
| Moderate | 0.3-0.7 cm | 30-60mL/ <50% | 0.2-0.4 cm2 | 1-2+ |
| Severe | ³0.7 cm | >60mL/³50% | ³0.4cm2 | 3-4+ |
Indications for AVR in primary aortic valve disease:
- ³5.0 m/s
- ³10mmHg in systolic blood pressure
- ³3 serial imaging studies
Indications for mitral valve repair or replacement in primarily aortic valve disease:
Indications for MV repair or replacement in primary mitral disease:
- ³40 mm
Indications for AVR in primarily mitral valve disease:
Preoperative Evaluation
Identification of symptomatology, severity of disease, and underlying causative disease processes are often well elucidated on a thorough history and physical. Patients with risk factors should undergo cardiac catheterization to rule out underlying ischemic pathology. Right heart catheterization will also allow for evaluation of pulmonary hypertension. Obtain an EKG to evaluate for arrhythmias as well as baseline for postoperative comparison. Transesophageal echocardiogram provides the best visualization of the atrioventricular valves. Doppler flow measurements are important to define severity of valve pathology. As combined aortic and mitral valvular disease progresses, one will often find subsequent tricuspid regurgitation due to progressive pulmonary hypertension and right heart dilation. Additionally, rheumatic disease may often contribute to both right and left sided valvular pathology.
Surgical Technique
Decision to repair or replace a valve is dependent upon the underlying disease pathology as well as technical considerations. Rheumatic disease tends to scar and fibrose thus repairs are less durable in this population. Alternatively, degenerative mitral regurgitation secondary to severe bicuspid or calcified stenotic aortic valve may be repaired with good long-term results. Preoperative TEE will allow the surgeon to plan a necessary repair by estimating the leaflet size and coaptation. For replacements, valve prosthesis selection is usually chosen from the same classification of valves in respect for need of anticoagulation and longevity of the valve. Surgical aortic valve replacements are preferred among patients <65 of age or life expectancy >20 years, asymptomatic patients with indication for intervention with no prohibitive risks.
Preservation of the fibrous skeleton and the central fibrous body is essential to maintain the functional mechanics and electrical conduction of the heart. Oversizing of mechanical valves can distort the aorto-mitral curtain. Additionally, if the aorto-mitral curtain is structurally compromised, one may need to consider reconstruction in addition to addressing the valves.
Cannulation
Surgical exposure is generally achieved through a median sternotomy. Alternative minimally invasive approaches including transcatheter, anterior thoracotomy, and robotic access are possible and not described in this chapter. Distal ascending aortic arterial inflow cannulation is performed.
Choice of venous cannulation is dependent on approach to mitral valve access and is often related to surgeon preference. A large hypertrophied heart may make a left atrial approach via the interatrial groove difficult. Alternately, a transseptal incision via the right atrium often confers good exposure. Consideration of the approach would infer corresponding two-stage right atrial cannula or bicaval cannulation.
Antegrade cardioplegia may be given for aortic valve stenosis; however, in the case of aortic insufficiency, poor diastolic arrest would necessitate retrograde or direct ostial cardioplegia. Additional volume may be necessary if there is severe ventricular hypertrophy. Full myocardial protection strategies are discussed elsewhere in this review book.
Sequence of valvular repair or replacement
After appropriate diastolic arrest, an aortotomy is performed and aortic valve inspected. A calcified valve usually necessitates replacement. The valve is then debrided and sized. Often after mitral valve repair or replacement the aortic valve will be smaller than initially sized. Consideration of BSA and annulus size must be made in case of necessary annular enlargement which is not possible after the mitral prosthesis is placed.
The mitral apparatus is then inspected. Repair or replacement of mitral valve is performed prior to aortic valve due to the risk of atrioventricular dissociation. Care is made to minimize lifting the heart after mitral repair or replacement is performed. Once the mitral valve has been appropriately managed and valve tested, the interatrial septum is closed with a patch or left atriotomy closed with running prolene sutures. Additional considerations would be left atrial appendage occlusion if atrial fibrillation is present preoperatively.
The aortic valve is then addressed, resized, and prosthesis inserted. After closing the aortotomy and deairing, the patient is weaned from bypass and valve function is assessed by TEE.
Specific technical details regarding individual mitral valve and aortic valve repairs and replacements individually can be found in the corresponding chapters.
Outcomes
Prior studies estimate mortality to be almost double that of single valve operations. However, operative mortality and overall survival have significantly improved with advances in myocardial protection. Most studies conclude an operative mortality of approximately 6%, and a 5- and 10-year actuarial survival of up to 88 and 81% respectively.
Risk factors for poor outcomes include advanced NYHA class, age, presence of coronary artery disease, pulmonary hypertension, diabetes mellitus, and aortic stenosis. Concomitant coronary artery surgery increases mortality following multiple valve surgery.
Bioprosthetic deterioration appears more related to valve position as there is a higher rate of earlier failure in the mitral position than aortic. Most studies cite similar rates of deterioration with multiple valve replacement. Surveillance imaging with TTE is recommended at 5 and 10 years, then annually. If there is a change in symptoms or echo findings, additional imaging is recommended.
Outcomes between two or more mechanical prostheses vs. two or more bioprosthetic valves show similar rates of thromboembolism. Mechanical valves are associated with anticoagulation related hemorrhage although higher freedom from operation.
Suggested Readings
- Acker M, W Hargrove, L Stephenson. Multiple valve replacement. Cardiol Clin 1985; 3: 425-430.
- Loo M, M Cunningham. Multivalvular Disease. Adult Cardiac. 2020. https://ebook.sts.org/sts/view/Cardiac-and-Congenital/1864068/all/Multivalvular_Disease. Accessed October 19, 2020.
- Nishimura R, C Otto, R Bonow, et al. 2014 AHA/ACC guideline for the management of patients with valvular heart disease: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2014;6(3):2438-2488.
- Otto CM, Nishimura RA, Bonow RO, et al. 2020 ACC/AHA Guideline for the Management of Patients with Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation 2021;143(5):e72-e227.
- Schaff H, R Suri. Multiple valve disease. Card Surg in the Adult, 5th ed. 2018. 943-963.
