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Eur J Cardiothorac Surg 2000;17:239-245
© 2000 Elsevier Science NL

Partial left ventriculectomy, ventriculoplasty or valvular surgery for idiopathic dilated cardiomyopathy – the role of intra-operative echocardiography

Cardiovascular Surgery, Shonan Kamakura General Hospital, 1202-1, Yamazaki, Kamakura, Kanagawa 247-8533, Japan

Corresponding author. Tel.: +81-467-46-1881; fax: +81-467-46-1881
e-mail: heartctr{at}fb3.so-net.ne.jp

	Abstract

Top Abstract 1. Introduction 2. Patients and methods 3. Results 4. Discussion Appendix A. Conference... References

 
Background: The partial left ventriculectomy (PLV) is known to work in some patients with dilated cardiomyopathy (DCM), although this procedure does not work well in all patients and the operative mortality is higher than the other cardiac surgeries. In addition to PLV, left ventriculoplasty to exclude antero-septal wall or valvular surgery without left ventricle (LV) surgery can be also effective in patients with DCM. To improve the surgical results for dilated cardiomyopathy, we introduced echo-guided volume reduction test and evaluated the surgical procedures and the results on the surgery for DCM. Methods: Between December 1996 and July 1999, 56 patients with DCM (50 with idiopathic DCM, six with dilated hypertrophic cardiomyopathy) were surgically treated. Under the standard cardiopulmonary bypass, left ventricular motion was determined with color kinesis of echocardiogram and the lesion of akinetic wall was removed or excluded. Results: After the initial PLV in 18 patients (initial group), operative procedures were selected in 21 with PLV, five with LV plasty, or 12 with valve surgery without LV surgery according to the findings of the LV wall motion by intraoperative echogram (select group). There were six hospital deaths and late follow-up deaths within 1 year in initial group, however, the mortality decreased significantly after the selection of the operative procedures; three hospital deaths and two late deaths in the select-group (P<0.05). Significant decrease of left ventricular diameter, the LV ejection fraction and endosystolic volume index were demonstrated after the LV surgery. The survival rate improved significantly after the selection of the operative procedures; 14 months survival rates was 50.0% in initial group and 73.1% in select group (P<0.05). Conclusion: Operative mortality decreased and late follow-up results improved after the selection of operative procedures according to the intraoperative volume reduction test.

Key Words: Dilated cardiomyopathy • Partial left ventriculectomy (PLV) • Left ventriculo plasty • Valve surgery • Volume reduction test • Color kinesis

	1. Introduction

Top Abstract 1. Introduction 2. Patients and methods 3. Results 4. Discussion Appendix A. Conference... References

 
Since Batista et al. [1] first reported partial left ventriculectomy (PLV), it has been increasing interest as a surgical treatment for end stage dilated cardiomyopathy (DCM) due to various etiology. The reason for seeking new surgical procedures for DCM is that the shortage of donors although cardiac transplantation is an established treatment for the lesions. At the same time endoventricular circular patch plasty to exclude antero-septal akinetic lesion was reported to be an effective procedure in ischemic dilated cardiomyopathy by Dor et al. [2,3]. Bolling et al. [4] also reported the midterm results of mitral surgery without left ventricle (LV) surgery for end stage DCM. The PLV worked well in some patients with DCM, however, the operative mortality is higher than the other established cardiac surgery. Therefore LV plasty to exclude antero-septal wall or valve surgery alone can be also discussed as a new approach for DCM. To improve the operative mortality and the indication for operative procedures for DCM, we introduced intraoperative echo-guided volume reduction test and evaluated the surgical procedures for DCM.

	2. Patients and methods

Top Abstract 1. Introduction 2. Patients and methods 3. Results 4. Discussion Appendix A. Conference... References

 
Between December 1996 and July 1999, 56 patients (49 men and seven women) with DCM were surgically treated at Shonan Kamakura General Hospital. The age ranged from 14 to 76 years (mean, 50 years). The etiology of DCM was idiopathic in 50 and dilated hypertrophic cardiomyopathy in six. Patients with DCM due to ischemic or valvular lesions were excluded in this study. The initial 18 patients received PLV of postero-lateral ventricular wall (Initial group), however, operative procedures were selected after the induction of color kinesis of cardiac echogram. After the install of cardiopulmonary bypass, cardiac echo-probe was directly placed on the beating heart. The basic concept of the volume reduction test is that changes of left ventricular wall motion and thickness can be seen by the direct vision of the cardiac echogram (HP SONO 5500, USA) when the left ventricle is decompressed under the cardiopulmonary bypass and the wall tension decreases. When a postero-lateral region stay thin and akinetic under this condition, PLV is performed (Fig. 1A), while LV plasty is performed when an antero-septal region is observed to be akinetic (Fig. 1B). In contrast, the entire LV becomes kinetic after the decrease of the wall tension, valve surgery alone is performed as a surgical indication (Fig. 1C). Based on this technique, which was introduced after the initial experience of PLV in 18 patients, either PLV, LV plasty or valve surgery was selected as an operative procedure in the following 38 patients (select group).

View larger version (54K): [in this window] [in a new window]   Fig. 1. Intraoperative echo-guided volume reduction test. (A) Before extracorporeal circulation (ECC) the posterior wall of left ventricle (LV) between papillary muscle is akinetic. After LV decompression with full flow of ECC the akinetic lesion remains and Batista's partial left ventriculectomy is selected as an operative procedure. (B) Before ECC, septum of the LV is akinetic. After LV decompression the akinetic lesion remains and Dor's endoventricular circular patch plasty is selected as LV volume reduction surgery. (C) Before ECC, whole wall of the LV is moderately akinetic. After LV decompression the akinetic lesion improves and solo-valve surgery (mitral and tricuspid valve plasty) is selected and no LV volume reduction surgery is performed.

Before and after the surgery, all patients were evaluated by cardiac echocardiogram. Except in emergent situation, magnetic resonance imaging, emission beam tomography (Imatron), gated cardiac pool scan and phase image analysis were performed to assess the left ventricular status before and after the operation. Preoperative catheter ventriculograms and pressure measurements were performed in patients with relatively stable condition. Intraoperative and postoperative data of cardiac function with Swan–Ganz catheter was measured in all patients. A pathological study was performed in all patients and all were diagnosed with histological findings compatible to those of DCM with no specific findings. After discharge from the hospital medical treatment was continued by the cardiologist and patients were followed-up by re-admission for examination of the cardiac function every 6 months.

2.2. Statistical analysis
Data were presented as mean±standard deviation. Cumulative survival rates were calculated by Kaplan–Meier estimation using the date of operation and the date of the last follow-up. A multivariate analysis of independent factors was performed with Cox's proportional hazard model analysis. A probability value of less than 0.05 was considered significant.

	3. Results

Top Abstract 1. Introduction 2. Patients and methods 3. Results 4. Discussion Appendix A. Conference... References

 
Eighteen patients received PLV (initial group) and the in following 38 patients (select group), based on the intraoperative volume reduction test, PLV was selected for 21 patients, LV plasty to exclude antero-septal wall for five patients, and valve operation alone in 12 patients (Table 1). Mitral or tricuspid surgery was indicated when there was moderate to severe (grade +3 or +4) regurgitation in association with dilated cardiomyopathy.

In the select-group, LV surgery and concomitant mitral surgery was performed in 24 patients and tricuspid annuloplasty in 14 patients. Valvular surgery without LV surgery was selected in 12 patients: mitral surgery was performed in 11 patients and tricuspid annuloplasty was performed in eight patients. The tricuspid valve was replaced with installation of a left ventricular assist device in one emergent shock patient who had no mitral lesion but developed multi-organ failure due to DCM before operation.

In the select group, an aortic cross clamp was not placed in 12 patients with the mean aortic cross-clamping time being 66.1±33.8 min in 26 patients. Cardiopulmonary bypass was performed in all patients with a mean bypass time of 130.6±38.2 min. Intra-aortic balloon pumping required in two patients (including preoperative requirement in one). There were three hospital deaths (one in elective operation and two in emergent operation). The cause of hospital death was congestive heart failure in two, and arrhythmia in one. Left ventricular assist device was installed at postoperative day 7 in one patient in whom intractable ventricular tachycardia and fibrillation occurred suddenly six days after the PLV with mitral valve replacement. Hospital mortality decreased significantly after the selection of the operative procedures (P=0.026) (Table 2).

The return of heart failure was seen in two late survivors in the initial group and four in the select group. Three of them were medically treated after re-admission and three underwent reoperation. The patient who underwent reoperation after initial PLV initially required no mitral procedure due to dilated hypertrophic cardiomyopathy. He developed mitral regurgitation 2 years after operation because annual dilatation with the posterior lesion of the left ventricle was not effectively removed because of the thick hypertrophied muscle. Repeated PLV and mitral valve replacement was performed at the second operation and he was discharged from hospital uneventfully.

Two patients required reoperation for dilatation of LV after valve surgery alone without LV surgery.

The longest survival was 28 months and postoperative New York Heart Association (NYHA) class was I–II in nine patients from the initial group and 26 patients from the select group. The survival rate after the operation (Fig. 2) was 50% in the initial group and 73.1% in the select group at 14 months (P=0.042) (Fig. 2).

View larger version (22K): [in this window] [in a new window]   Fig. 2. Kaplan–Meier survival rate after left ventricular volume reduction surgery in initial 18 patients and 38 patients with selection of operative procedures for idiopathic dilated cardiomyopathy. The 14-months survival rate after operation, including emergent cases, was 50.0% in initial 18 patients (initial group) and the rate after the selection of the surgery in 38 patients improved significant to 73.1% (select group).

	4. Discussion

Top Abstract 1. Introduction 2. Patients and methods 3. Results 4. Discussion Appendix A. Conference... References

 
Heart transplantation or implantation of mechanical support [6,7] had been only a choice for surgical treatment for end-stage dilated cardiomyopathy. It has been very effective surgical therapy to manage the end-stage heart failure, however, the shortage of donor organs and the indication for the transplantation limit the candidate for the treatment [8]. Many new alternative treatments have been attempted and PLV has been performed since Batista et al. reported the effectiveness of the surgery in 1995 [1]. Several results [9–13] regarding PLV have been reported and most of them described high hospital mortality after the operation. Meanwhile LV plasty with the use of patch for akinetic lesion in patients with ischemic cardiomyopathy was reported by Dor et al. [2,3] with acceptable early and late follow-up results. Bolling et al. also reported that the solo-valve surgery could improve early and mid-term results in patients with DCM [6,14]. These three different types of operation have the advantage of using the patients own heart for repair. Therefore, complicated strategy to treat in patients with end-stage DCM could be considered in addition to the heart transplantation.

In this paper we focused on surgical treatment without heart transplantation in patients with idiopathic DCM excluding other etiology, because the heart transplantation has not been repeated in Japan for several reasons. We applied operative procedures of PLV followed by Batista's description initially to remove the posterior heart muscle and to reduce the diameter of LV [15]. However, we noticed that the myocardial damage was not homogeneous but focally diseased in dilated heart after the initial experience and clinicopathological findings. During the operation, we could also recognize that the gross findings and the palpation of the inside left ventricle showed different findings in each patients. This evidence was also pathologically proven by the findings of the excised posterior heart muscle and remaining septal muscle. Therefore we considered that the decision making to resect posterior wall of the heart was very important for the treatment with PLV. And thus we applied intraoperative echographic evaluation of the heart muscle in addition to several preoperative examination of the cardiac function and muscular condition. After the induction of this technique, PLV was not applied in all patients with dilated cardiomyopathy but was applied in patients with akinesis of LV posterior wall. To reduce the size and volume of LV, five patients was required LV plasty with antero-septal exclusion because the posterior motion was better than the antero-septal one and the akinesis of the septal wall remained after the volume reduction under cardiopulmonary bypass. Valve surgery without LV surgery was also effective as entire wall motion improved after the volume reduction test, although two in three patients with very enlarged LV required volume reduction surgery after the initial mitral surgery. Prediction of reduction of LV size is difficult because a proper size can depend on myocardial stiffness, because normalization of the diameter of the LV might cause diastolic disorder in patients with high stiffness of the ventricle [16,17].

Mitral regurgitation is associated in most cases with end-stage DCM because of the enlargement of the mitral annulus. Bolling et al. reported that isolated mitral annuloplasty with undersized prosthetic ring could be performed with low operative mortality and morbidity [14]. In our patients with valve surgery alone, no hospital death was noted in elective cases, however, late morbidity was high, especially in patients with severely dilated hearts although the EDVI decreased even after the valve surgery alone.

After deciding operative procedure by the use of intra-operative echo-guided assessment, 12 out of 38 patients selected valve surgery alone and seven of them recovered in NYHA class I–II after the operation. Therefore this particular valve surgery without ventricular surgery may work in a certain subject of DCM with severe mitral regurgitation and small amount of akinetic heart muscle with no severe dilatation.

In the initial 18 patients, six patients died in hospital after surgery and three died of heart failure in late follow-up within 1 year following PLV. Three of six patients died in hospital more than 30 days after surgery because of diastolic dysfunction due to small size of LV after excessive muscle excision. Two patients died within 1 year of the operation also because of diastolic dysfunction. All these patients were operated in our initial experiences and we considered that it was not necessary to make the LV as small as normal heart and it was important to leave good LV muscle by removing diseased muscle according to the findings of color kinesis. Therefore, after the selection of the operative procedure with intraoperative echo-test, the mortality both in hospital and in late follow-up improved significantly; three hospital deaths and two late deaths from 38 patients.

Although the use of an intraoperative volume reduction test does not always predict definite procedures for an uneventful postoperative course, postoperative management became easy and no hospital deaths due to congestion, however, one patient with sudden VT 7 days after operation were seen after the induction of the test. The prediction of appropriate postoperative LV size is difficult even after the use of intraoperative volume reduction test, however, postoperative histogram of phase image in gated cardiac pool scan seemed to be useful predictor of recurrent of postoperative heart failure. When a successful operative procedure either PLV, LV plasty, valve surgery without ventricle surgery, was performed, the histogram became close to normal with small standard deviation value. However, the patients who died in hospital or recurred heart failure after their discharge showed no improvement of the deviation regardless postoperative LV size.

Emergent operation was not indicated for volume reduction surgery as seen in the heart transplantation because of a low success rate. Conclusively, the intraoperative volume reduction test can be used to select the operative procedures – either volume reduction surgery such as PLV, LV plasty, or valve surgery without LV surgery. After the selection of the operative procedures, hospital mortality decreased and postoperative early heart failure decreased. Postoperatively, careful follow-up with cautious medical management for heart failure is important and reoperation or heart transplantation is advisable when medically uncontrollable heart failure recurred after the non-transplant cardiac surgery.

	Acknowledgments

 
We acknowledge the statistical analysis by Dr Masanori Yoshida.

	Footnotes

 
Presented at the 13th Annual Meeting of the European Association for Cardio-thoracic Surgery, Glasgow, Scotland, UK September 5–8, 1999.

	Appendix A. Conference discussion

Top Abstract 1. Introduction 2. Patients and methods 3. Results 4. Discussion Appendix A. Conference... References

 
Mr J.R.L. Hamilton (Newcastle-upon-Tyne, UK): Thank you very much, Dr Isomura, for a very concise and well-presented study. This is always a challenging operation. It's one that I have no experience with. Any comments from the audience?

Just out of interest, to give us a feel of the numbers of surgeons doing this procedure, has anybody here got experience of the Batista procedure? One? Two? It seems that it is not particularly widespread. Dr Isomura, I understand that in Japan until recently you haven't had transplantation?

Dr Isomura: We have done just three cases recently, but it's quite few numbers.

Mr Hamilton: Are these patients that might have been considered for transplant in other countries?

Dr Isomura: Yes. Some patients would like to go abroad for the heart and that's the reason why we continue doing this kind of surgery.

Mr Hamilton: So do you see this as an alternative to transplantation or are they in a different group of patients?

Dr Isomura: Well, actually, I have no idea. But a more recent paper published by Dowling's group, Louisville shows that it's comparable to the heart transplantation in the United States, just for the 12 months follow-up.

Mr J. Pepper (London, UK): Which do you think is more important, resecting the muscle or reconstructing the mitral valve?

Dr Isomura: Well, definitely if the heart is very large, I think it is warranted to resect the muscle. But with diameters around 65 or 70 and the severe mitral regurgitation, you can do only the mitral valve replacement or repair. That's going to work, I think.

	References

Top Abstract 1. Introduction 2. Patients and methods 3. Results 4. Discussion Appendix A. Conference... References

 

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