Posterobasal Left Ventricular Aneurysms

Abstract

This retrospective study analyzes short- and long-term outcomes in 18 patients who underwent repair of posterobasal left ventricular aneurysm from January 1993 through December 2009. As concomitant procedures, mitral reconstruction was performed in 4 patients, ventricular septal defect repair in 2 patients, and coronary artery bypass grafting in 17 patients. In regard to surgical technique, 10 patients underwent patch repair and 8 underwent closure by linear suture.

The in-hospital mortality rate was 11% (2 patients). An intra-aortic balloon pump was placed postoperatively in 1 patient. One patient underwent reoperation for mediastinitis and 2 for bleeding. The 1-, 5-, and 10-year survival rates were 82%, 76%, and 52%, respectively.

Posterobasal left ventricular aneurysm repair can be performed with low short-term mortality rates and good long-term outcomes. It must be judged whether a linear repair or patch repair is better, in accordance with aneurysm size and the concomitant operative procedure, if any.

Posterior left ventricular (LV) aneurysms are less common than anterior aneurysms.^1–3 Their prevalence in large series has usually been reported as less than 10%.^2–4 The posterobasal part of the heart is supplied by the left circumflex coronary artery and by terminal branches of the right coronary artery.⁵ Pathologic states of these branches cause inferoposterior or posterolateral LV aneurysm.³ Posterior aneurysms can be accompanied by various degrees of mitral insufficiency⁶ and by ventricular septal defects (VSD).⁷ A 2004 study reported mitral insufficiency of grade 2/4 or higher in all 13 patients who underwent repair of aneurysm due to posterior myocardial infarction (MI).⁶

Our study investigates operative results among patients who underwent surgery for posterior LV aneurysm. Our surgical approach is discussed in terms of short- and long-term outcomes.

Patients and Methods

From January 1993 through December 2009, 18 patients (12 men and 6 women) underwent operation for posterior LV aneurysm. Their median age was 60.05 ± 11.38 years (range, 43–85 yr). The data were collected retrospectively from patient records. The current status of the patients was determined through telephone interviews and the examination of patients' cards. Transthoracic echocardiography and cineangiography had been performed for the diagnosis of all patients; aneurysms were revealed by echocardiography or left ventriculography. Coronary artery disease and target vessels were identified by means of coronary angiography. All operations were elective. The chief clinical symptoms were angina and dyspnea (symptomatic of congestive heart failure). The 18 patients' preoperative characteristics appear in Table I.

TABLE I. Preoperative Characteristics of the 18 Patients

For statistical analysis of the data, we used SPSS for Windows 15.0 (IBM Corporation; Armonk, NY). In the evaluation of study data, we used the Kaplan-Meier test to determine mean, SD, and frequency, and also to perform survival analysis. Significance was considered to be P < 0.05.

Surgical Technique

Aortic arterial and bicaval venous cannulation were performed. The vent cannula was inserted in the right upper pulmonary vein. All surgical procedures were performed with the aorta cross-clamped and the patient under cardioplegic arrest. During the arrest period, isothermic blood cardioplegic solution was administered continuously and in a retrograde fashion via the coronary sinus, for myocardial protection. The diaphragmatic surface of the heart was explored after sponging. The largest part of the posterior aneurysm was opened parallel to the posterior descending artery in such a manner as to equalize the amount of scar tissue on each side of the incision. Thrombus inside the aneurysm, if any, was excised. When a patch was to be used, the transitional zone between healthy myocardial tissue and scar tissue was identified. An elliptical or spherical patch was then sewn circumferentially so that the 3-0 sutures passed through healthy myocardial tissue. Upper scar tissue was then sewn onto the patch with 2-0 Prolene, in an over-and-over fashion. In the event of repair via linear closure, some scar tissue was resected from each side. Both sides were supported by Teflon bands, and the rest of the aneurysmal tissue was repaired with over-and-over sutures. Saphenous anastomoses of the distal left circumflex and right coronary arteries were performed after aneurysm repair. Left atriotomy enabled exploration in 3 of the 4 patients who underwent mitral repair, and the transseptal approach from the right atrium was used in the remaining patient. One patient underwent an Alfieri repair, another a ring annuloplasty, and 2 a posterior suture annuloplasty. Two patients underwent repair of a ventricular septal defect; both were explored via ventriculotomy and were repaired with a Dacron patch sutured with 3-0 Prolene. Eventually, a left internal mammary artery–left anterior descending coronary artery anastomosis and proximal saphenous anastomoses were performed under aortic cross-clamping.

Results

The hospital mortality rate was 11% (2 pts) (Table II). One patient who underwent VSD repair as a concomitant procedure died of low cardiac output; and another who underwent mitral ring annuloplasty as a concomitant procedure died after a cerebrovascular accident. Three other patients needed mechanical ventilation for longer than 48 hours. An intra-aortic balloon pump was placed in 1 patient during the postoperative period. One patient developed mediastinitis. Two patients underwent reoperation because of bleeding.

TABLE II. In-Hospital Deaths and Major Morbidities in the 18 Patients

Perioperative data appear in Table III. All operations were performed with the patient cross-clamped and under cardioplegic arrest. Ten patients underwent repair with a patch (6 with Dacron, 4 with pericardium), and 8 patients underwent linear suture closure. Mitral valve repair was performed as a concomitant procedure in 4 patients, and VSD repair in 2 patients. Simultaneous coronary artery bypass grafting was performed in 17 of the 18 patients.

TABLE III. Perioperative Data on the 18 Patients

One of the 16 surviving patients was lost to long-term follow-up. Four of the 16 surviving patients died in the long term. The 1-, 5-, and 10-year survival rates were 82%, 76%, and 52%, respectively (Fig. 1).

Fig. 1 Graph shows the long-term survival of 17 patients* who successfully underwent repair of posterobasal left ventricular aneurysms and concomitant lesions.

*This graph excludes only the patient who was lost to follow-up.

Discussion

The first aneurysm repair with the use of cardiopulmonary bypass was reported in 1958 by Cooley and colleagues,⁸ who used the linear closure method. In subsequent years, repair with a patch was described and then widely accepted, with various modifications.^9–11 Both in past and recent years, posterior aneurysms have been reported less often than anterior aneurysms. In large series,^2–4 posterior aneurysms have usually accounted for less than 10% of the left ventricular aneurysms described.

Our in-hospital mortality rate, as we have said, was 11.1%. Prêtre and colleagues⁵ reported the death of 1 of 15 patients (6.7%) who underwent repair of posterobasal aneurysm. In another study of inferior aneurysm,¹² the early mortality rate was 5.8%.

In our study, simultaneous mitral intervention was applied to 4 patients who had moderate or severe mitral insufficiency. Other investigators have reported numerous reconstruction techniques for the correction of mitral insufficiencies that accompany posterior aneurysm.^13,14 In our study, the Alfieri technique was applied to 1 patient, ring annuloplasty to 2 patients, and posterior leaflet reconstruction to another 2 patients. Local deformities in the mitral leaflet complex appear to be more common after inferior MI than after anterior MI.¹⁵ It has been reported that the development of progressive mitral insufficiency after inferoposterior MI is related to the repositioning of ischemic papillary muscles associated with LV dilation and remodeling.¹⁶ In our study, mitral intervention was not performed in patients who displayed minimal or mild mitral insufficiency.

Ten of our patients underwent repair with a patch and 8 underwent primary closure. In their study of patients who had undergone linear closure or patch repair, Lange and colleagues¹ observed no difference in operative mortality rates, clinical improvement, or survival rates. Indeed there is no consensus in the medical literature regarding a preferred surgical method. It has been noted, however, that the anatomic and physiologic characteristics of each patient can govern selection.¹⁷ Cavity width and shape and the diameter of the scar tissue are crucial in selecting the technique.¹⁸ Prêtre and colleagues⁵ mentioned that preoperative and operative findings played a part in determining the surgical technique applied in their series of 15 posterobasal aneurysm repairs. In our series, the existence of VSD or mitral insufficiency was not a determinant of surgical technique. Typically, linear repair was preferred in small aneurysms and patch repair in large.

Comparable to other postoperative results reported in the literature,¹⁹ our 5-year survival rate after posterior aneurysm repair, including early deaths, was 76%, and our 10-year survival rate was 52% (Fig. 1). The long-term outcomes of posterior aneurysm repair have in fact been similar to those of anterior aneurysm repair.¹⁹

In conclusion, posterior LV aneurysm repair can be performed with low hospital mortality rates and good long-term outcomes. Whether to apply the patch or the linear repair method should be decided in accordance with the aneurysm's size and possibly in accordance with the concomitant procedure, if any. In our judgment, linear repair is best applied to small aneurysms. Patch repair is preferable in the cases of large lesions and extensive scar tissue.