Introduction
Infective endocarditis (IE) has remained stable over time, however, the type of IE and rate of surgical intervention has changed. Patients are now more elderly, rheumatic heart disease is less common and invasive cardiac procedures with implantations are increasing. Moreover, intravenous substance abuse leading to IE is on the rise. In turn, the population requiring surgical intervention has increased in complexity [ , ]. About 40%–45% of all patients with IE will ultimately require surgical intervention, which has plateaued since the 2007 guidelines for antibiotic prophylaxis for IE [ , ]. Regardless, there is still a significant proportion of patients requiring surgical intervention for IE, and with this comes the need for complex surgical approaches for multivalvular IE [ ]. Indications for the surgical treatment of IE include valvular dysfunction leading to heart failure, new-onset conduction abnormality, those with persistent septic pulmonary or systemic emboli, persistent vegetation greater than 1 cm or persistent left-sided endocarditis after full treatment of antibiotics in highly virulent organisms such as S. aureus , fungi or multidrug-resistant organisms. [ ]
Since IE requiring surgical intervention requires extensive debridement of all involved tissues, there are frank indications for a multivalvular operation with or without intervalvular fibrous body and atrial reconstructions. While double-valve operations are most common, there are case reports of triple and quadruple valve replacements for IE [ ]. The presentation and surgical management of double-valve replacement/repair of the aortic and mitral valve will be of focus here, but principles of double-valve endocarditis can be applied to even more complex situations. Additionally, the topic of single valve endocarditis is a focus of this text elsewhere.
Epidemiology
Data are limited on multivalvular involvement in IE. In one single-center study of 1571 patients undergoing surgical intervention for IE, 46% underwent aortic valve replacement (AVR), 31% underwent mitral valve replacement (MVR), 14% underwent combined AVR and MVR (of which 11% had intravalvular fibrous body (IFB) involvement). Of those with IFB involvement, all had replacement of the AVR and MVR. An additional 16% had repair of the tricuspid valve. Other concomitant procedures included aortic root replacement (60%), ascending aorta or partial arch replacement (20%), and coronary artery bypass grafting (32%) [ ]. In another single-center study of 72 patients with IE of the aortic valve with mitral involvement, annular involvement was present in 12.5% [ ]. Thus, multivalvular IE can require extensive surgical repair after completely eliminating infective tissues. Inpatient mortality has been reported to be 18% with a five-year survival rate ranging between 25% and 94% in those with double-valve endocarditis with or without IFB involvement [ , ]. Mid to long-term follow-up of 37 patients with invasive aortic IE with IFB and anterior mitral valve involvement repaired with an aortomitral homograft, revealed an in-hospital mortality of 8%, postdischarge mortality of 5%, and one-year and three-year survival rates of 91% and 82%, respectively [ ].
Surgical evaluation
One of the most common multivalvular IE clinical scenarios involves aortic valve endocarditis with drop lesion extension to the anterior leaflet of the mitral valve or less commonly, an erosive abscess with extension into the intervalvular fibrous body. Preoperative transthoracic echocardiography (TTE) supplemented by intraoperative transesophageal echocardiography (TEE) can aid in the operative approach. Cardiac catheterization should be done only in those suspected of coronary artery disease, however, coronary Computed Tomography Angiogram (CTA) is reasonable in many cases, especially those with aortic valve involvement. Notably, presence of suppurative pericarditis is strongly suggestive of fibrous body involvement [ ]. All patients should have their dentition evaluated for abscess prior to cardiac surgical intervention, unless hemodynamically unstable from a readily surgically reversible cause. Similarly, enteric organisms on culture should prompt evaluation for ongoing abdominal sources of infection prior to surgical intervention. It is recommended to clear bacteremia prior to surgical intervention if possible (i.e., not operate during active acute IE).
Surgical approach
A proper midline sternotomy and bicaval cannulation should be performed in order to allow for the full spectrum of both left and right-sided repairs, included complex aortic root or fibrous body reconstructions [ ]. Preoperative TEE should be performed just prior to starting the operation in order to evaluate the full spectrum of disease, ensure IE has not evolved to more valves and there has not been embolization or change in character of any vegetations. Additionally, cardiac manipulation should be avoided as to prevent vegetations from producing septic emboli. When only aortic or mitral valve involvement is presumed, it is sensible to inspect the other for simultaneous involvement. Repair rather than replacement of a valve should be done in order to prevent subsequent prosthetic valve endocarditis, however, nuanced decision making for the valve in question should be considered (see other chapters of single valve repair). If an abscess is discovered, it should be drained with full debridement of the surrounding tissue. In an extensive ring abscess or involvement of the fibrous body, reconstruction may be necessary with dacron or pericardial patch. In atrioventricular discontinuity, a bridging patch may be necessary [ , , ].
“Hemicommando” and “commando” procedures have been described in the setting of aortic and mitral valve IE with IFB involvement [ , ]. The “commando” procedure involves double-valve replacement with IFB reconstruction. Here, the aortic root is opened transversely and cardiac buttons are formed from each coronary ostia ( Fig. 19.1A ). This exposes the aortic valve, which can then be excised widely to healthy tissue, bringing into view the mitral valve and annulus underneath ( Fig. 19.1B ). The IFB and noncoronary cusp is incised and the mitral valve and annulus can be excised as needed ( Fig. 19.1C ). Upon full excision of both the mitral and aortic valves (prosthetic mitral valve depicted here), a single atrioventricular cavity is seen ( Fig. 19.2 ) . Suturing of the new mitral valve is done from posterior to anterior on the annulus, with the anterior-most annulus meeting the IFB and noncoronary position of the aortic annulus, near the junction of the left and noncoronary cusps ( Fig. 19.1D ). The IFB can be reinforced with surrounding tissue of the native or prior aortic and mitral valves or pericardial patch ( Fig. 19.1E ). The aortic homograft can now be sewn in at the new IFB and aortic root ( Fig. 19.1F ). The dome of the left atrium is sometimes incised in order to improve the view the mitral valve, and this too can be closed by fashioning a pericardial patch ( Fig. 19.1G ) [ , ].
