Pathologic changes in the cardiac valves requiring surgical correction of more than one valve can result from rheumatic heart disease, degenerative valve diseases, infective endocarditis, and a number of other miscellaneous causes. Further, valve dysfunction may be primary; that is, a direct result of a disease process, or secondary; that is, caused by cardiac enlargement and/or pulmonary hypertension. Surgical management is influenced both by the underlying cause of valve dysfunction and, when valves are involved secondarily, by the anticipated response to replacement or repair of the primary valve lesion. In addition, the consequences of various combinations of diseased valves on left and right ventricular geometry and function frequently are different from the remodeling as a result of single-valve disease. This chapter addresses pathophysiologic considerations in multivalvular heart disease, surgical techniques, and management of commonly encountered etiologies.

Repair of multiple lesions was necessary even in the early development of operative management of valvular heart disease (Table 44-1). The first triple-valve replacement during a single operation was reported in 1960, and simultaneous replacement of all four valves was reported in 1992.¹

Experience from clinical practice indicates that multiple valve disease requiring surgical correction occurs in a few common combinations. As seen in Table 44-2, multiple procedures account for approximately 15% of all operations on cardiac valves; 80% of these operations involve the aortic and mitral positions. Replacement of the mitral and tricuspid valves (with or without aortic replacement) accounts for 20% of operations. Only rarely is the combination of aortic and tricuspid disease encountered.

Valvular regurgitation may result from the pathologic process affecting the valve directly or may be secondary to alterations in ventricular morphology caused by other valve lesions; this secondary or functional regurgitation affects the atrioventricular valves. In some patients, secondary valvular regurgitation may be expected to improve with repair or replacement of the primarily diseased valve. In other patients, the secondary disease process may have advanced to the stage that valve function will not improve following correction of the primary lesion, and thus simultaneous surgical correction should be considered.

Primary Aortic Valve Disease with Secondary Mitral Regurgitation

Isolated aortic valve lesions can cause secondary regurgitation of the mitral valve and rarely, the tricuspid valve. Severe aortic valve stenosis with or without left ventricular dilatation frequently is associated with some degree of mitral valve regurgitation. In one series, 67% of patients with severe aortic valve stenosis had associated mitral valve leakage.² When the mitral valve is structurally normal, its regurgitation would be expected to improve with relief of left ventricular outflow obstruction;⁴ mild mitral valve regurgitation may, at times resolve almost completely after aortic valve replacement. Improvement in mitral valve regurgitation results from both decreased undergoing intraventricular pressure and ventricular remodeling.⁵ If mitral valve regurgitation is severe, some degree of persistent regurgitation is expected after aortic valve replacement, and mitral valve annuloplasty may be required. In contrast, with aortic valve stenosis and mitral valve regurgitation associated with a structurally abnormal mitral valve, repair or replacement of the mitral valve usually is necessary. A recent report alleges that moderate MR has an adverse impact on survival in elderly patients undergoing aortic valve replacement and suggests that those with intrinsic mitral valve disease should be considered for concurrent correction.⁶

Thus determination of the morphology and pathophysiologic severity of each valve lesion is critically important in planning surgical management, and preoperative and intraoperative echocardiographic studies are necessary in all patients suspected of having multiple valve disease. Often, transthoracic echocardiography can define the etiology of mitral and tricuspid valvular regurgitation. When valve regurgitation is entirely secondary, the mitral valve leaflets will appear thin and freely mobile, without prolapsing segments. Mitral (and tricuspid) valve regurgitation secondary to rheumatic disease is readily identified when leaflets are thickened and chordae are shortened; fibrosis of these structures restricts leaflet mobility. Leaflet prolapse with or without ruptured chordae tendineae also may cause atrioventricular valve regurgitation.

Transesophageal echocardiography images the heart from a retrocardiac position, which avoids interference from interposed ribs, lungs, and subcutaneous tissue. A high-frequency (5-MHz) transducer is employed, which yields better resolution than that of images obtained with routine transthoracic imaging with 2.25- to 3.5-MHz transducers.⁷ Thus transesophageal echocardiography provides the best image of the mitral and tricuspid valves and may be obtained preoperatively. Intraoperative transesophageal Doppler echocardiography should be employed in all patients having valve repair or replacement, and the technique is especially important for assessment of response of MR to relief of left ventricular outflow obstruction.⁸ In some cases, preoperative left ventriculography may help to quantify left atrioventricular valve leakage. Right ventricular angiocardiography also can be useful in determining the degree of tricuspid valve dysfunction, but it is rarely employed in current practice.⁹

Tricuspid Valve Regurgitation Secondary to Other Valvular Disease

Secondary tricuspid valve regurgitation commonly is associated with rheumatic mitral valve stenosis, and the exact cause is unknown.^10,11 Some authors believe that secondary tricuspid valve regurgitation is a result of pulmonary artery hypertension and right ventricular dilatation.¹² As with the mitral valve, tricuspid valve annular dilatation in those with severe TR is asymmetric. Most enlargement occurs in the annulus subtended by the free wall of the right ventricle, and there is little dilation of the annulus adjacent to the septal leaflet of the tricuspid valve.^13,14 Although pulmonary artery hypertension with secondary enlargement of the right ventricle and tricuspid valve annulus may be an important contributing factor in secondary tricuspid regurgitation (TR), it is not the sole mechanism. For example, congenital heart lesions such as tetralogy of Fallot produce systemic pressure in the right ventricle, yet severe tricuspid valve regurgitation rarely is seen in these patients. Similarly, important tricuspid valve regurgitation is uncommon in children with ventricular septal defects who have enlargement of the right ventricle associated with variable degrees of pulmonary hypertension.

Furthermore, clinical experience suggests that other mechanisms must play a role in development of secondary tricuspid valve regurgitation. Patients who have had mitral valve replacement for rheumatic mitral valve stenosis may develop regurgitation of their native tricuspid valve years after initial operation, and many patients have only modest elevation of pulmonary artery pressure.^15,16 Recent evidence points to a progressive immunologic process in rheumatic valve disease, which can lead to severe TR many years after successful percutaneous or surgical management of the mitral valve.¹⁷

It is useful to classify secondary mitral and tricuspid valve regurgitation as mild, moderate, and severe.¹⁴ Usually, patients with mild tricuspid valve regurgitation do not have clinical signs and symptoms of right-sided heart failure. Also, mild TR demonstrated by preoperative echocardiography may appear even less severe in the operating room under general anesthesia. In most instances, mild secondary TR does not require intervention.

Patients with echocardiographic evidence of significant regurgitation who do not have symptoms or have their symptoms controlled by medical treatment are managed with a DeVega suture annuloplasty or a partial-ring annuloplasty.¹⁸ Patients with severe secondary TR and clinical evidence of right-sided heart failure (eg, pulsatile liver, distended neck veins, and peripheral edema with or without ascites) are most frequently managed by concomitant ring annuloplasty or tricuspid valve replacement.¹⁹

The degree of pulmonary hypertension may influence surgical management of secondary tricuspid valve regurgitation. Kaul et al²⁰ grouped 86 patients with functional TR in association with rheumatic mitral valve disease according to the degree of pulmonary hypertension. One group had severe pulmonary hypertension (mean pulmonary pressure 78 mm Hg), and a second group had moderate pulmonary hypertension (mean pulmonary artery pressure 41 mm Hg). Patients with moderate pulmonary hypertension preoperatively had more advanced right-sided heart failure and right ventricular dilatation, and many of these patients continued to have tricuspid valve regurgitation following mitral valve surgery without tricuspid valve surgery. The patients with severe pulmonary hypertension all showed regression of TR, and 28% had complete resolution following mitral valve surgery without operation on the tricuspid valve.

The difficulty with interpretation and generalization of current literature guiding management of secondary functional TR is the significant heterogeneity in both patient disease substrate and surgical procedure performed. The incidence of severe late TR has been reported to be approximately 68% up to 30 years following mitral replacement for rheumatic disease.²¹ The risk of significant late secondary TR is as high as 74% 3 years following repair of ischemic MR.²² The most frequently identified risk factors for TR progression from these series include older age, female gender, rheumatic etiology, atrial fibrillation, the absence of a Maze operation.^21-24 Therefore, most would agree that correction of moderate or greater TR at the time of surgery for rheumatic mitral disease is indicated to prevent the development of symptoms associated with TR progression.²⁵ Less clear however is whether long-term survival is improved by such intervention.²⁴ Recent evidence suggests that remodeling annuloplasty in the patients with tricuspid annular dilatation (≥70 mm) at the time of mitral repair significantly decreases the risk of subsequent functional deterioration compared with those having tricuspid valve repair.²⁶ Furthermore, reliance on tricuspid annular dilation alone as suggested by Dreyfus et al²⁶ has recently been challenged.²⁷

In contrast, although mitral valve prolapse is the most frequent cause of MR in the developed world, there are few reports addressing the incidence and fate of functional TR following successful mitral valve repair. Recent data suggest that moderate or less functional TR does not progress as aggressively following repair of leaflet prolapse as in rheumatic or ischemic mitral disease subsets.^28,29 Outcomes following isolated mitral valve repair or replacement for degenerative MR with less than severe coexistent functional TR at Mayo Clinic support the notion that risk of TR progression is low after MVr or MVR for MV prolapse. The authors recommend timely MV surgery before the development of left atrial dilatation or pulmonary hypertension, which would be expected to decrease the risk of TR progression during follow-up. Current indications for concomitant tricuspid valve repair under these circumstances include: (1) moderately severe or severe TR, (2) right-sided heart failure symptoms with moderate or severe TR, (3) moderate TR with one of the followings: primary tricuspid valve disease, structural abnormalities of the tricuspid valve (including impingement of the tricuspid leaflets by pacemaker leads), a dilated right atrium and right ventricle, severe pulmonary hypertension, or atrial fibrillation.¹⁹

A long-term outcome study of the prognostic impact of isolated TR confirmed that the presence of a mild-to-moderate isolated TR was not associated with a survival difference in comparison to those with trivial regurgitation, even after multivariable adjustment (p = .34).³⁰ (In summary, asymptomatic, less-than-moderate functional TR associated with degenerative mitral valve disease is unlikely to progress or impact survival following successful mitral valve repair.)

When multiple valve replacement is confined to the left ventricle, replacement valves are generally chosen from the same class with respect to the need for anticoagulation and projected longevity. There are no theoretical or practical advantages to use of a tissue valve and a mechanical valve for mitral and aortic valve replacement, and studies show no reduction in the risk of thromboembolism, valve-related morbidity, or late death.^31,32 In addition, a lower reoperation rate is reported for patients with two mechanical valves in the left ventricle compared with patients with one mechanical and one tissue valve.³¹

For tricuspid valve replacement, alone or in conjunction with other valve procedures, use of a bioprosthesis may have advantages in regard to minimizing risk of valve thrombosis.^33,34 Furthermore, there are few hemodynamic considerations in selecting a tricuspid prosthesis; the greater hemodynamic efficiency of mechanical valves compared with bioprostheses rarely is an issue in atrioventricular valve replacement, especially the tricuspid valve, in which the annulus diameter in adults is often 33 mm or more. In vitro studies demonstrate only minimal hemodynamic improvement with atrioventricular valves larger than 25 mm.³⁵

Aortic and Mitral Valve Replacement

CANNULATION

Arterial inflow is established by cannulation of the distal ascending aorta near the pericardial reflection just to the left of the origin of the innominate artery (Fig. 44-1A). Venous cannulation is simplified by using a two-stage cannula in the right atrium for venous return. Individual cannulation of the superior and inferior venae cavae is reserved for operations that require right atrial or ventricular incisions (Fig. 44-2A). Provisions for intraoperative autotransfusion are used routinely, and antifibrinolytic drugs such as aprotinin or epsilon-aminocaproic acid (Amicar) may be useful, especially in reoperations, in which pericardial adhesions may worsen bleeding.³⁶

CARDIOPLEGIA

If the aortic valve is competent, myocardial protection during aortic cross-clamping is achieved by initial infusion of cold (4 to 8°C) blood cardioplegia through a tack vent placed in the aorta proximal to the clamp. The volume of cardioplegia needed to achieve diastolic arrest and uniform hypothermia depends on the heart size and the presence of aortic valve regurgitation. Generally, the initial volume of cardioplegia required for hearts with multiple valve disease is higher than that required for coronary revascularization because of myocardial hypertrophy. For patients without cardiac enlargement, we infuse approximately 10 mL/kg of body weight, whereas 15 mL/kg of body weight is used for patients with significant degrees of myocardial hypertrophy. Repeat infusions of 400 mL of cardioplegia are given directly into the coronary ostia at 20-minute intervals during aortic occlusion. We use custom-designed, soft-tipped coronary perfusion catheters to minimize the potential for trauma to the coronary ostia during intubation and infusion.³⁷

If aortic valve regurgitation is moderate or severe, cardioplegia is infused directly into the coronary ostia. Initial aortotomy is facilitated by emptying the heart using suction on an aortic tack vent and temporarily reducing the cardiopulmonary bypass flow rate to maximize venous return. Some surgeons prefer retrograde infusion of cardioplegia,³⁸ and if this method is used, even larger volumes are necessary because of non-nutritive flow through the coronary venous system and variation in coronary venous anatomy.^39,40

PROCEDURE

After cardioplegia, the aortic valve is inspected through an oblique aortotomy extended into the noncoronary aortic sinus (see Fig. 44-1B). Aortic valve regurgitation caused by cuspal perforation or prolapse of a congenitally bicuspid valve often can be repaired,⁴¹ but the decision for or against aortic valve repair should take into consideration whether or not a mitral valve prosthesis will be needed. For example, even though aortic valve repair might seem technically possible, prosthetic replacement may be the best option for a patient who requires mitral valve replacement and will be maintained on warfarin for long-term anticoagulation.

Severe calcification of the valve, whether it is bicuspid or tricuspid, necessitates replacement;⁴² therefore, the cusps are excised and annular calcium debrided carefully. The aortic annulus then is calibrated; experience has shown that subsequent replacement of the mitral valve usually reduces the aortic annular diameter by shortening the circumference that is in continuity with the attachment of the anterior mitral valve leaflet. Therefore, we routinely identify (but do not break the sterile packaging of) two aortic prostheses: one corresponds to the calibrated dimension, and the other is the next size smaller. Final selection of the aortic prosthesis is made after mitral valve replacement or repair.

Although exposed first, the aortic valve usually is replaced after mitral valve repair or insertion of the mitral valve prosthesis. Sutures placed in the portion of the aortic valve annulus that is continuous with the anterior leaflet of the mitral valve pull the anterior leaflet superiorly toward the left ventricular outflow area and thus hinder exposure of this area as viewed through the left atriotomy.

If the aortic annulus is small, it can be enlarged with a patch of pericardium.⁴³ This technique increases annular diameter by 2 to 4 mm or more, and only rarely are more radical techniques necessary.^44-46 Another maneuver to accommodate as large a prosthesis as possible is to place the necessary sutures for the mitral valve repair or replacement but not secure the mitral prosthesis until the aortic valve is implanted. This eliminates downsizing of the aortic prosthesis but does not compromise insertion of sutures in the superior portion of the mitral valve annulus.

After removal of the aortic valve, the right atrial cannula is repositioned, and the mitral valve is exposed through an incision posterior to the interatrial groove (see Fig. 44-1B). The presence or absence of thrombi in the left atrium is noted, and the mitral valve is inspected. When there is rheumatic disease of the aortic valve, the mitral valve almost always will be involved to some extent. If aortic valve replacement is necessary, the surgeon should have a low threshold for replacing a diseased mitral valve because scarring and fibrosis of the rheumatic process are progressive, and mitral valve repair (commissurotomy for stenosis or leaflet repair and annuloplasty for regurgitation) is less durable than repair for degenerative disease.^47-49 In contrast, when aortic valve replacement is necessary because of calcification of a bicuspid valve or senescent calcification, repair of mitral valve regurgitation owing to degenerative causes can be expected to give predictably good long-term results. Repair of the mitral valve is described in Chapter 41.

In preparation for replacement, the anterior leaflet of the mitral valve is excised, and when possible, a portion of the posterior leaflet with its chordal attachments is preserved to maintain left ventricular papillary muscle-annular continuity.^50-52 Some surgeons make a special effort to preserve the anterior leaflet and its chordal attachments, believing that this has a further beneficial effect on ventricular performance.⁵³ The mitral prosthesis is implanted using interrupted mattress sutures of 2-0 braided polyester reinforced with felt pledgets, which can be situated on the atrial or ventricular side of the valve annulus (see Fig. 44-1C). The leaflets of mechanical valves should be tested for free mobility following valve seating.

When atrial fibrillation is present preoperatively, we obliterate the left atrial appendage by oversewing its orifice from within the left atrium or ligating it externally. The left atriotomy is closed from each end with running polypropylene sutures. Vent tubing is inserted through the partially closed left atriotomy and left in place while the aortic valve is being replaced (see Fig. 44-1D).

After appropriate exposure, the aortic prosthesis is sewn in place with interrupted 2-0 polyester mattress sutures backed with felt pledgets, and the aortotomy is closed, usually with two layers of 4-0 polypropylene. Any remaining air is evacuated from the heart with the usual maneuvers, and a tack vent in the ascending aorta is placed on suction as the aortic clamp is removed. The vent is removed from the left atrium, and closure of the left atriotomy is secured.

In patients with annuloaortic ectasia, the mitral valve sometimes can be visualized and replaced through the enlarged aortic annulus.⁵⁴

Aortic Valve Replacement and Mitral Valve Repair

Intraoperative transesophageal echocardiography is useful in assessing the degree of MR and, importantly, in identifying the cause of valve leakage. When mitral valve regurgitation is only moderate and leaflet morphology is normal, we expect mitral valve function to improve following relief of severe aortic stenosis. In all other instances, the valve should be inspected directly to determine the need for repair or replacement.

Sternotomy, cannulation, and assessment of the aortic valve proceed as described previously. When there is no indication of tricuspid valve disease and no other right atrial procedures are planned, venous return is obtained through a single two-staged cannula (Fig. 44-3A). Specific techniques of mitral valve repair depend on operative findings.⁵⁵ Localized prolapse of a portion of the posterior leaflet with or without ruptured chordae usually is managed by triangular excision of that segment and repair with continuous 4-0 polypropylene suture.⁵⁶ Ruptured chordae to the anterior leaflet are replaced with 4-0 or 5-0 polytetrafluoroethylene (PTFE) sutures inserted into papillary muscle and through the free edge of the prolapsing leaflet.⁵⁷

Almost all leaflet repairs are supplemented with a posterior annuloplasty. Interrupted 2-0 braided polyester mattress sutures are placed along the posterior circumference of the annulus ending at the right and left fibrous trigones (see Fig. 44-3A). Sutures then are spaced evenly through a flexible 6.0- to 6.5-cm–long partial ring; this standard length can be obtained by using a flexible 63-mm posterior annuloplasty band.^49,58 Following annuloplasty, competence of the mitral valve is tested by filling the ventricle with saline or blood; the atrium then is closed, and the aortic valve prosthesis is sewn into place.

Mitral Valve Replacement and Tricuspid Valve Replacement or Repair

In most instances, tricuspid valve regurgitation is caused by annular dilatation.⁵⁹ The severity of tricuspid valve leakage can be determined by transesophageal echocardiography before bypass and by digital exploration of the right atrium just before venous cannulation. Under general anesthesia, changes in blood volume and cardiac output can cause significant fluctuation in the amount of regurgitation, and most often the severity of tricuspid valve leakage is lessened in the immediate prebypass period.

The patient’s clinical condition must be correlated with echocardiographic findings and intraoperative assessment of the tricuspid valve. Patients with an enlarged, pulsatile liver, peripheral edema, and jugular venous distention are likely to require tricuspid valvuloplasty following mitral valve replacement or repair. Patients without the stigmata of right-sided heart failure usually have less severe valve leakage, and tricuspid valve function may improve without direct repair or replacement after left-sided valvular lesions are corrected.

The decision for repair or replacement of functional tricuspid valve regurgitation at the time of mitral valve replacement is important because the risk of subsequent reoperation is high. In our earlier experience, operative mortality was 25% in patients who required later reoperation for tricuspid valve regurgitation. Further, TR progresses in 10 to 15% of patients after replacement of rheumatic mitral valves.⁶⁰ Therefore, we maintain a liberal policy for annuloplasty or prosthetic replacement at initial operation.⁶¹

PROCEDURE

For operations on the tricuspid valve, insertion of a Swan-Ganz catheter is optional; if one is used, the catheter is withdrawn from the right heart chambers during inspection and assessment of the tricuspid valve. We prefer direct cannulation of the inferior and superior venae cavae.⁶² After commencement of cardiopulmonary bypass and cardioplegia, the cavae are snared around the venous cannulae, and the interatrial septum and tricuspid valve are exposed through a right atriotomy (see Fig. 44-2A). A decision for repair or replacement of the tricuspid valve is made, and the necessary prosthesis is identified.

When the tricuspid valve is also addressed, we tend to expose the mitral valve through an incision in the interatrial septum, which crosses the fossa ovalis and can be extended superiorly (see Fig. 44-2B). Care should be taken during retraction to avoid tearing the septum inferiorly toward the coronary sinus and triangle of Koch. Alternatively, the mitral valve can be exposed through a standard left atriotomy posterior to the interatrial groove.

After repair or replacement of the mitral valve (see Fig. 44-2C), the septal or left atrial incision is closed, and the tricuspid valve is repaired or replaced. For tricuspid valve repair, we use either the DeVega method or ring annuloplasty.^12,18,63,64 Both techniques are based on the observation that the anterior and posterior valve portions of the tricuspid valve annulus are more prone to dilatation than the septal leaflet portion of the annulus, as described previously. When ring annuloplasty is indicated, we prefer a flexible device such as the Cosgrove-Edwards prosthesis⁶⁵ or a partial Duran ring (see Fig. 44-3B). The use of a partial ring avoids placement of sutures in the annulus near the penetrating bundle of His and reduces risk of injury to conduction tissue. There have been conflicting reports regarding the superiority of DeVega procedure versus prosthetic annuloplasty in improving freedom from recurrent TR.^66-68

Minimally Invasive Approaches

Although addressed elsewhere in this textbook, minimally invasive approaches to primary and reoperative left- and right-sided valvular heart disease have been proposed. Various cannulation and cardioplegia techniques have been described as determined by the pattern of valve disease and patient anatomy.^69a,b

Tricuspid Valve Replacement and Pulmonary Valve Replacement for Carcinoid Heart Disease

If there is no involvement of the mitral and aortic valves,^59,70 tricuspid and pulmonary valve replacement usually can be performed without the need for aortic occlusion and cardioplegic arrest. It is important to exclude the presence of a patent foramen ovale to eliminate the risk of air entering the left atrium, and if a defect in the atrial septum is identified, it is closed using a brief period of aortic occlusion. In the past, our strategy for patients with carcinoid heart disease was to replace the tricuspid valve and excise the diseased pulmonary valve.

Subsequent experience has suggested that right ventricular function is better preserved with a competent pulmonary valve, so we now favor pulmonary valve replacement rather than valvectomy.⁷¹ Tricuspid valve replacement always is indicated, and it is usually necessary only to remove the anterior leaflet. A recent review of 200 patients with carcinoid heart disease at our institution demonstrated that prognosis has improved in the current era and that valve replacement surgery was independently associated with prolonged survival.⁷²

Carcinoid disease produces fibrosis and retraction of the leaflets, so anchoring sutures (interrupted mattress sutures of 2-0 braided polyester backed with felt pledgets) can be inserted into the remaining septal and posterior leaflets. We prefer to position the pledgets on the ventricular side of the valve annulus. If exposure is difficult, a brief period of aortic clamping and cardioplegic arrest is used during placement of sutures in the posterior and septal leaflets; the aortic cross-clamp is removed, and the heart is allowed to beat rhythmically. The remaining sutures are placed, and all sutures are secured with observation of the electrocardiogram. If atrioventricular block develops, the sutures in the area of the penetrating bundle of His are removed and reinserted in a more superficial location.

Pulmonary valve replacement is performed through a longitudinal incision across the valve annulus onto the outflow portion of the right ventricle. We prefer to insert the prosthetic valve using a continuous 3-0 polypropylene suture, anchoring the sewing ring to the native valve annulus for approximately two-thirds of the valve annulus and then anteriorly to a pericardial patch that is used routinely to augment the valve annulus and facilitate closure of the pulmonary artery and right ventricle.

Triple-Valve Replacement

Operative preparation is similar to that described previously. Usually left-sided valvular lesions are corrected before tricuspid valve procedures. Again, if there is aortic valve regurgitation, the aortotomy is performed first, and cardioplegia is administered; simultaneously, we snare the cavae and open the right atrium. After excision of the aortic valve and calibration of the annulus, the interatrial septum is incised, and the mitral valve is repaired or replaced. Next, the aortic valve is implanted, and after closure of the aortotomy and septotomy, the tricuspid valvuloplasty or prosthetic replacement can be performed without aortic cross-clamping.⁷³

As shown in Table 44-3, rheumatic valvulitis is a common cause of multiple valve disease. Autopsy studies show that almost all patients with rheumatic heart disease have some involvement of the mitral valve, although it is not always evident clinically.⁷⁴ The percentages of multiple valve involvement in two autopsy studies of patients with rheumatic heart disease are shown in Table 44-4.

Forty-seven percent of those studied had involvement of more than one valve. Mitral and aortic valve disease was the most common combination and was present in 34% of patients; the second most common combination was mitral, aortic, and tricuspid valve disease (9%). A recent report has suggested that all four valves might be involved with the rheumatic process.⁷⁵

Long-term follow-up of children with rheumatic heart disease suggests that approximately 50% of patients have multivalvular involvement.^76,77 In a study of patients undergoing mitral valvotomy for rheumatic mitral stenosis (Table 44-5), 13% had clinical evidence of other rheumatic valve stenosis or regurgitation. Most of these patients had associated rheumatic aortic disease.⁷⁸

Rheumatic heart disease can cause valve stenosis, regurgitation, or a combination of lesions. The percentages of 290 patients with specific valvular lesions from four studies of multiple valve disease are shown in Table 44-6. Mixed lesions producing stenosis and regurgitation were encountered most commonly in both aortic and mitral valves.

Rheumatic Mitral Stenosis with Rheumatic Aortic Regurgitation

Approximately 10% of patients with rheumatic mitral valve stenosis also have rheumatic aortic regurgitation.^79,80 Clinical and laboratory characteristics of patients with mitral stenosis and aortic regurgitation are summarized in Table 44-7.

PATHOPHYSIOLOGY

In patients with mitral valve stenosis and aortic valve regurgitation, decreased cardiac output minimizes the classic signs of aortic regurgitation (eg, waterhammer pulse, head bobbing, and visibly pulsating capillaries). Also, concomitant mitral stenosis reduces left ventricular volume overload, which is a characteristic of isolated aortic regurgitation.⁸¹ The underfilling of the left ventricle characteristic of mitral stenosis is offset by overfilling secondary to aortic valve regurgitation. Pulmonary artery hypertension characteristic of mitral stenosis usually is present.

OPERATIVE DECISION-MAKING

Patients with rheumatic mitral stenosis and rheumatic aortic regurgitation of more than a mild degree usually require replacement of both valves. Aortic valve repair is possible using techniques such as cuspal extension with glutaraldehyde-treated bovine or autologous pericardium⁸² or the Trussler technique.⁸³ Although early results with cuspal extension have been good, inexorable progression of valve fibrosis may necessitate later prosthetic replacement for many patients.⁸⁴