Endoventricular Remodeling of Left Ventricular Aneurysm
Functional, Clinical, and Electrophysiological Results
Background Recent advances in surgical techniques for the repair of left ventricular aneurysms (LVAs) include the use of an endoventricular patch to exclude the aneurysm cavity. This technique has replaced conventional linear plication of the aneurysm. The endoventricular patch technique remodels the left ventricular cavity to a more physiological geometry that improves function.
Methods and Results From December 1989 through November 1993, 45 patients underwent an LVA repair with an endoventricular patch. This procedure was performed in association with coronary artery bypass grafting in 40 patients. Twenty-eight patients (62.2%) also had nonguided encircling subendocardial incisions. Operative procedures included 7 emergency operations, 3 concomitant valve procedures, and a mean of 2.2 bypass grafts per patient. Eight patients had previous cardiac operations. Hospital mortality was 15.6% (7/45) for all patients and 9.1% (3/33) for nonemergent revascularization and LVA repairs. Ejection fraction improved from a mean of 25.8% preoperatively to 37.8% postoperatively; the mean New York Heart Association classification improved from 3.5 to 1.5. Of patients known to have preoperative arrhythmias (inducible or sudden death), 69% were not inducible postoperatively without antiarrhythmic medication. Survival from late cardiac death (including death of unknown origin) was 86.5% at 2 years. Freedom from documented ventricular arrhythmias was 94.3% at 2 years.
Conclusions These results indicate that the patch endoaneurysmorrhaphy technique can provide an excellent functional and physiological outcome in patients with LVAs and severely impaired ventricular function.
Formation of LVAs is common after myocardial infarction1 2 and can result in CHF, areas of dyskinesia, mural thrombi, and ventricular arrhythmias. A congenital LVA was repaired in 1919 by the simple suture ligation of a ventricular diverticulum in a neonate.3 In 1954, Litkof and Bailey repaired a series of six patients with a closed tangential excision of the LVA.4 Modern LVA repair was first described in 1958 by Cooley et al,5 who used an open excision and linear repair with cardiopulmonary bypass. In the late 1980s, several techniques for geometric preservation of the ventricle during LVA repair were advanced by Jatene,6 Cooley et al,2 7 8 and Dor et al.9 These newer techniques resulted in marked improvement in postoperative left ventricular function,7 and it later became evident that these operations conferred protection from the postoperative ventricular arrhythmias frequently encountered in these patients.10 The present study reports our results for LVA repair with the use of the combined approach of an endoventricular patch remodeling technique plus an encircling subendocardial incision for arrhythmia control.
From December 1989 through November 1993, LVA repair was performed on 45 consecutive patients at New York University Medical Center. An LVA was clinically defined as an area of infarcted left ventricular myocardium with resultant scarring and thinning of the ventricular wall with paradoxical motion during systole. LVA repair procedures included emergency operations, concomitant valve procedures, and operations on patients who had undergone previous cardiac surgery (Table 1⇓). Indications for surgery included angina (95%) and congestive heart failure (32%). Data were collected on preoperative variables, including age, sex, angina, NYHA classification, symptoms, CHF, and other comorbid conditions, as shown in Table 2⇓.
Preoperative and Postoperative Studies and Tests
Ejection fraction was measured preoperatively by left ventriculography in all patients. Among the 38 operative survivors, postoperative ventriculography was performed in 20 patients (52.6%), and postoperative ejection fraction was documented with gated nuclear scan in 20 patients (52.6%). Electrophysiological testing was performed preoperatively in patients (n=19) who had a history of ventricular tachycardia or survival from sudden cardiac death. Postoperative EPSs were performed in 27 of the 45 patients.
All patients underwent cardiopulmonary bypass with myocardial arrest achieved by cold blood cardioplegia, administered either antegrade or retrograde, along with topical hypothermia. Coronary artery revascularization was performed when possible. In this series, all aneurysms were on the anterior ventricular wall with septal involvement. The aneurysm was directly incised after cardioplegic arrest to remove the thrombus and evaluate the extent of both myocardial scarring and ventricular deformity. All patients with a preoperative history of arrhythmias had a concomitant encircling subendocardial incision performed at the junction of normal and infarcted muscle. This incision frequently extended well down onto the septum. An endoaneurysmorrhaphy patch (made of synthetic polyester textile fiber) was placed at the orifice of the aneurysm cavity as previously described by Cooley.7 8 Sutures were placed at the junction of scarred and viable myocardium, with a running suture of 3-0 polypropylene. Varying amounts of the interventricular septum were excluded by the patch depending on the extent of septal infarction, often resulting in exclusion of 50% to 75% of the septal area.11 The residual aneurysm wall was subsequently closed over the patch.
Follow-up Study and Statistics
Follow-up was obtained on all patients by patient and family interview. Any death from an unknown cause was considered a cardiac death. Statistical analysis was performed with spss software, and a value of P<.05 was considered significant. All values are presented as mean unless otherwise indicated. Actuarial curves for mortality or late complications were obtained by use of the life-table method.
Hospital mortality was 15.6% (7 of 45) overall and 9.1% (3 of 33) for isolated nonemergent LVA repair with concomitant coronary artery bypass grafting. Left ventricular endoaneurysmorrhaphy was accompanied by concomitant coronary bypass grafting in 40 patients and concomitant valve procedures in 4 patients. Twenty-nine patients had the left anterior descending artery bypassed. Five patients required postoperative intra-aortic balloon pumps, and 1 of these patients also required a left ventricular assist device. Three of these 5 patients died in the hospital. The preoperative left ventricular ejection fraction, which had a mean of 25.8% (range, 12% to 49%), increased by 14.3% after aneurysm repair; an improvement in ejection fraction was noted in 94% of hospital survivors (the Figure⇓).
Nineteen patients (42%) had a history of ventricular arrhythmia. Of this group, 13 patients had documented sustained arrhythmia on EPS preoperatively or clinically manifested as survival from sudden cardiac death. The remaining 6 patients had high-grade ventricular arrhythmia documented on 24-hour monitoring.
EPSs were performed postoperatively on 27 patients. Six patients had inducible ventricular arrhythmia while they were not on antiarrhythmic medication. Two of these patients had no prior history of arrhythmia. Five of 6 inducible patients were successfully treated with antiarrhythmic medication, and 1 had placement of an internal defibrillator. Of the 13 patients with documented sustained arrhythmia, 9 (69%) were not inducible postoperatively while off antiarrhythmic medication.
Clinical follow-up was obtained in all patients, with a mean follow-up interval of 15.7 months. Postoperative NYHA classification improved from 3.5 to 1.5. Freedom from cardiac death at 1 and 2 years was 97.0% and 86.5%, respectively. Freedom from all complications (reoperation, CHF, infection, and thromboembolism) was 67% at 2 years.
Freedom from documented ventricular arrhythmias was 94.3% at 2 years. Of the four late deaths, two were attributable to CHF and occurred at 4 months and 4 years, respectively. The cause was unknown in the remaining two patients but was presumed to be due to ventricular arrhythmias. Both of these patients had preoperative ventricular tachycardia. The first patient had polymorphic ventricular tachycardia in association with an acute myocardial infarction. He was not inducible either before or after operation, and he died 18 months after his repair. The second patient was a sudden death survivor who was inducible postoperatively, discharged on suppressive amiodarone therapy, and died 14 months later. If one assumes that both of these patients had sudden cardiac death, then 2-year freedom from all ventricular arrhythmias is reduced to 84.0%.
Operative repair of LVAs has evolved from conventional repair with linear plication of the aneurysm sac to include remodeling of the ventricular cavity. In 1985, Jatene6 reported aneurysmorrhaphy with reduction of the orifice of the aneurysm. This technique was thought to preserve the geometry of the ventricle and thereby improve ventricular function. This operation was performed on a beating heart; an encircling purse-string suture was used to reduce orifice size of the aneurysm, and the repair was closed with an epicardial synthetic polyester patch. Cooley described “ventricular endoaneurysmorrhaphy,” a procedure that repairs the aneurysm by placing an intracavitary synthetic polyester patch at the junction of normal and scarred tissue.7 8 This technique utilized cardioplegic arrest and placement of an endoventricular patch with subsequent closure of the aneurysm sac over the repair. Dor et al9 similarly reported a technique that utilized autologous endocardial scar as the patch material to reduce the aneurysm cavity. This technique, like that of Jatene and unlike that of Cooley, relied on suturing epicardium directly to the patch, thus leaving an epicardial suture line under ventricular tension and without coverage.
The restoration of the natural left ventricular geometry theoretically accounts for the improved myocardial function seen with these repairs.2 12 Restoration of the ventricular geometry reduces the paradoxical contractile forces. The end-diastolic volume is decreased, thereby diminishing wall tension, which in turn decreases myocardial oxygen demand. The postrepair ventricle can function therefore on a more leftward point on the Starling curve. In our study, we also observed an increase in the ejection fraction in an overwhelming majority of patients (the Figure⇑). Because some of the operations were done emergently and the patients were referred from other institutions, the patients could not all have the same modality of ejection fraction preoperatively.
Our analysis used the available data to represent the most complete evaluation possible of the change in patient cardiac function, but mixing the various measurement techniques used is an inherent weakness in this approach. However, what is not disputable is the change in clinical status in NYHA classification. Preoperatively, all patients were either NYHA class 3 or 4 with significant myocardial dysfunction. Although this procedure carried a mortality of nearly 10%, the late improvement in the quality of life was remarkable, with the majority of patients decreasing their NYHA classification by two classes.
An inherent part of the development of these various techniques for improving left ventricular function is the interruption of pathways for arrhythmia propagation. To some extent, all techniques of endoaneurysmorrhaphy eliminate potential arrhythmic pathways by placing suture lines in the border zone of the endocardial scar. Using this technique alone, Sosa et al13 reported a success rate of 94% in the immediate control of inducible ventricular tachycardia after aneurysm repair in a group of 19 patients with previous ventricular tachycardia. Dor et al10 aggressively addressed the issue of potential arrhythmias by including a nonguided endocardiectomy and/or endocardiotomy as part of the LVA repair along with nonguided cryotherapy. Postoperatively, 92% of the patients in that series were noninducible with programmed stimulation, in contrast to our noninducibility rate of 69% in patients with prior arrhythmia or inducibility. It is unclear how significant this difference is, but it is tempting to suggest that the liberal use of cryoablation by Dor et al was responsible for decreasing postoperative inducibility beyond the reduction achieved by subendocardial incision alone.
Nevertheless, analysis of our long-term data revealed similar antiarrhythmic results. In our series, the 2-year freedom from ventricular tachycardia was 84%. If the four deaths of unknown origin in the group studied by Dor et al were assumed to be arrhythmic in origin (the same assumption we used in the analysis of our data), the freedom from ventricular arrhythmia in that study would be identical with our results.
Disturbing and unresolved is the fact that in all series there are late sudden deaths in patients with negative postoperative ventricular stimulation testing.10 13 Thus, although EPSs are the best available method for predicting postoperative arrhythmias, these studies are not infallible, and false negatives do occur.
In summary, this series of ventricular aneurysm repairs in patients with poor cardiac function demonstrates that coronary revascularization and use of the endoaneurysmorrhaphy technique provide dramatic improvement in patient functional status. The results also suggest that an encircling subendocardial incision provides good freedom from the ventricular arrhythmias associated with this condition.
Selected Abbreviations and Acronyms
|CHF||=||congestive heart failure|
|LVA||=||left ventricular aneurysm|
|NYHA||=||New York Heart Association|
Presented in part at the 67th Scientific Sessions of the American Heart Association, Dallas, Tex, November 14-17, 1994, and published in abstract form (Circulation. 1994;90[pt 2]:I-640).
- Copyright © 1995 by American Heart Association
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