Abstract
Left ventricular (LV) aneurysms most frequently occur as a consequence of maladaptive remodeling after a large infarction. Surgical ventricular restoration involves aneurysmectomy and LV volume reduction. Patient selection, appropriate placement of the endoventricular circular Fontan suture, and concomitant revascularization or valve repair is essential for success.
Keywords
heart failure, left ventricular aneurysm, ventricular remodeling, surgery
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Amelioration of left ventricular (LV) remodeling is an appealing target for medical and surgical therapies for heart failure. Remodeling is a complex process that leads to maladaptive ventricular dilation, hypertrophy, and altered ventricular wall stress and may occur after large myocardial infarction, chronic ischemia, or chronic valvular heart disease.
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The most distinct sequela of remodeling is aneurysm formation at the site of infarction. Transmural infarcts result in full-thickness necrosis and scar formation, with subsequent thinning and infarct expansion secondary to mechanical stretch. Nontransmural infarcts alter regional compliance resulting in infarct area bulging and expansion. The net result is formation of a ventricular aneurysm and increased LV volume.
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Consequently, surgical ventricular reconstruction (SVR) primarily involves aneurysmectomy and LV volume reduction. These operations are almost always done concomitantly with coronary artery bypass grafting or mitral valve surgery.
Step 1
Surgical Anatomy
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LV aneurysms occur at the site of infarction, most frequently anterior apical (90%) after left anterior descending (LAD) and posterior (10%) after circumflex (Cx) infarcts.
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Important anatomic considerations are the location of major coronary arteries, such as the LAD and Cx relative to the proposed ventriculotomy ( Fig. 30.1 ; arrow indicates LAD).
Figure 30.1
Step 2
Preoperative Considerations
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Indications for operation include:
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congestive heart failure
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angina
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aneurysm expansion and rupture
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arrhythmia
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embolism
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Preoperative left heart catheterization is mandatory. Complete revascularization should be performed to viable myocardial territories. An LV aneurysm can be well delineated on the ventriculogram during catheterization, as demonstrated in Fig. 30.2 (highlighted by red arrows ).
Figure 30.2
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The size of the ventricle and location of the akinetic or dyskinetic portion are critical and require additional diagnostic imaging, such as via echocardiography or cardiac magnetic resonance imaging (MRI). There are no established size criteria for SVR; however, SVR can be considered when the LV end-systolic volume index is more than 80 mL/m 2 or the end-diastolic volume index is more than 120 mL/m 2 .
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The degree of mitral regurgitation should be quantified before surgery by echocardiography. Mitral valve annuloplasty and/or replacement should be performed if severe. Fig. 30.3 shows an apical aneurysm in the four-chamber view.
Figure 30.3
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Cardiac MRI can measure aneurysm size, ventricular morphology, and myocardial viability. Cardiac MRI can aid in planning revascularization strategy and extent of the scar. Fig. 30.4 is an MRI scan of an apical infarction. Note the thinning of the anterior wall and apex ( red arrows ), delineating the extent of the aneurysm.
Figure 30.4
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If ventricular arrhythmia is an issue, preoperative endocardial mapping is useful for possible concomitant ablation during SVR.
Step 3
Operative Steps
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A median sternotomy and central cannulation for cardiopulmonary bypass are performed. If mitral valve surgery is planned, bicaval cannulation is performed. Cardiopulmonary bypass is initiated. To prevent potential embolization from a small LV thrombus, care is taken to prevent manipulation of the heart.
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The akinetic or dyskinetic segment of the left ventricle can be identified intraoperatively by the characteristic dimpling or flattening of the anterior wall after the aortic cross-clamp is applied and the LV vent is on ( Fig. 30.5 ).
