Nontransplant Cardiac Surgery

Abstract

Partial left ventriculectomy and mitral valve repair, alone or in combination, have been used successfully to treat adult patients with end-stage dilated cardiomyopathy, yet the clinical results of this procedure in small children have been described only rarely. We report 2 cases of nontransplant cardiac surgery in small children with end-stage dilated cardiomyopathy. The 1st patient received both a partial left ventriculectomy and mitral valve repair; the 2nd received only mitral valve repair. Subsequently, both underwent successful heart transplantation.

We believe that nontransplant cardiac surgery can improve clinical status and act as a biological bridge, instead of a mechanical bridge, to heart transplantation in small children with end-stage dilated cardiomyopathy. (Tex Heart Inst J 2002;29:213–5)

Nontransplant cardiac surgical procedures—including partial left ventriculectomy (PLV) and mitral valve repair, alone or in combination—have been used successfully to treat adult patients with end-stage dilated cardiomyopathy (DCM). ¹ Yet the clinical results of this procedure in small children have been described only rarely in the English medical literature. ^2–5 We present 2 cases of nontransplant cardiac surgery in small children with end-stage DCM. The 1st patient received both a partial left ventriculectomy and mitral valve repair; the 2nd received only mitral valve repair.

Case Reports

Patient 1

In June 1999, we operated on a 3½-year-old girl who had a body weight of 11.5 kilograms. She had experienced progressive exertional dyspnea since the age of 5 months, when she had viral myocarditis. Echocardiography and left-heart catheterization in August 1996 had showed DCM. The dyspnea had improved initially with medical treatment, but had grown worse over time. Echocardiograms at 40 months of age, when compared with echocardiograms at 7 months, showed an increase in left ventricular end-diastolic dimension (LVEDD) from 36 mm to 74 mm; during the same period, left ventricular ejection fraction (LVEF) decreased from 0.41 to 0.18. Mitral regurgitation at 40 months of age was moderate (2+). In May 1999, the patient was hospitalized, placed on a waiting list for heart transplantation, and given continuous intravenous infusions of multiple inotropic agents.

Decreasing urine output and other indications of progressive clinical deterioration prompted us to perform nontransplant cardiac surgery in order to save the patient's life. We selected PLV because of her large left ventricle and moderate mitral regurgitation. Standard cardiac anesthesia and a hemodynamic monitor were used. The left atrial pressure was 22 mmHg.

The operation was slightly different from the methods of Batista. ⁶ Continuous antegrade cold blood cardioplegia was used for cardiac arrest and myocardial protection. We resected a triangular section of the lateral wall of the left ventricle between the papillary muscles. The mitral valve was repaired by approximating the centers of the free edges of the anterior and posterior mitral leaflets with a single suture of 4-0 pledgetted Ticron (Alfieri's repair ⁷). The aortic cross-clamp time was 57 minutes.

Postoperatively, intravenous milrinone was administered for 2 weeks, and amiodarone was used to prevent ventricular arrhythmia. The patient was discharged 1 month after surgery and was monitored at an outpatient clinic, where she was determined to be in New York Heart Association (NYHA) functional class II. Echocardiography 1 month after the surgery showed a smaller heart (LVEDD, 58 mm) and slightly improved contractility (LVEF, 0.26). She received digitalis, furosemide, and losartan after the surgery.

However, our patient had recurrent heart failure 6 months after the surgery. Echocardiography showed redilatation of the left ventricle (LVEDD, 63 mm) and moderate mitral regurgitation. She was again placed on the transplantation list and underwent successful orthotopic heart transplantation 10 months after the surgery.

Histologically, the specimen of left ventricular wall excised during PLV displayed diffuse myocytic hypertrophy, interstitial edema, and very mild interstitial fibrosis. There was no inflammatory cell infiltrate. After transplantation, the recipient's explanted heart showed marked diffuse endocardial fibrosis and a scar along the border of the previous ventricular incision.

Patient 2

In April 2000, we operated on a 2-year-old boy, who had a body weight of 9 kilograms and had been in heart failure since birth. Echocardiography showed DCM. As in our other case, the patient's exertional dyspnea had improved initially with medical treatment, but had grown worse over time. Also, repeat echocardiography showed a decrease in myocardial contractility between the ages of 2 months and 2 years: during this time, the LVEF decreased from 0.47 to 0.25. The LVEDD was 52 mm at 2 years. Cardiac catheterization in April 2000 showed DCM with moderate-to-severe mitral regurgitation (3+) and severe pulmonary hypertension.

The child was hospitalized, placed on a waiting list for heart transplantation, and given continuous intravenous infusions of multiple inotropic agents. However, because of intractable failure, he soon had to be intubated and supported with very-high-dose epinephrine (0.15 μg/kg per min), dobutamine (15 μg/kg per min), dopamine (10 μg/kg per min), and milrinone (0.3 μg/kg per min).

Because death was imminent, emergency nontransplant cardiac surgery was performed. We chose mitral valve repair without ventriculectomy, because mitral regurgitation was moderate to severe and the left ventricle was comparatively small. The left atrial pressure was 43 mmHg. The mitral valve was reconstructed by means of Alfieri's repair ⁷ and Wooler's posterior annuloplasty. The aortic cross-clamp time was 42 minutes.

Postoperatively, an angiotensin-II antagonist (losartan) was used for afterload reduction. The patient was discharged 1 month after surgery and was monitored at an outpatient clinic for 2 months, where he was found to be in NYHA functional class II. Echocardiography 1 month after surgery showed a smaller heart (LVEDD, 45 mm) and mild-to-moderate mitral regurgitation. The LVEF was 0.28.

However, the boy had recurrent heart failure 3 months after surgery, was relisted for transplantation, and underwent successful orthotopic heart transplantation 5 months after surgery.

Discussion

Nontransplant cardiac surgery for heart failure—including endoventricular circular patch placement (the Dor procedure ⁸), PLV, mitral valve repair, and the installation of various mechanical blood pumps—has appeared to offer promising alternatives to heart transplantation. ^1,9 However, because the long-term outcomes of these alternative therapies have not yet been established, heart transplantation (when available) is still the treatment of choice for patients with end-stage heart failure. In our hospital, we have performed nontransplant cardiac surgery only as a life-saving procedure or as an alternative for transplant candidates who have been rejected because of old age or comorbid conditions. In patients with DCM, we have performed mitral valve repair in cases of more-than-moderate mitral regurgitation^* and have performed PLV in cases of less-than-moderate mitral regurgitation or of severe left ventricular enlargement.

Reports of the early results of PLV were promising. ^10,11 The reported operative mortality rate has ranged from 0 to 30% ^1,9 and the 2-year survival rate from 50% to 60%. ^1,9–11 Congestive heart failure may persist in 15% to 25% of patients after PLV. ¹¹ At 1 year, freedom from death or from the need be listed again for heart transplantation was 56%. ¹¹ Since 1997, we have performed PLV in 7 patients (6 adult and 1 pediatric, including Patient 1) with end-stage DCM. There was no operative mortality, but 1 patient died of sepsis at 6 postoperative months and another of arrhythmia at 1 year. In all cases, we considered the procedure a bridge to transplantation; of the 5 survivors of PLV, 3 have received donor hearts and 2 have received clinical follow-up without transplantation.

Bolling and colleagues ¹² have shown favorable early and intermediate-term outcomes of mitral valve repair in patients with end-stage dilated cardiomyopathy. (Most of their patients were hemodynamically stable before surgery.) Preoperatively, the mean peak volume of oxygen consumption among Bolling's patients during exercise was 14.5 mL/kg per min. The surgical outcome was poor in patients with severe heart failure, but the overall 1- and 2-year actuarial survival rates were 82% and 71%, respectively. Twenty-four months after surgery, left ventricular volume and sphericity had decreased, while ejection fraction and cardiac output had increased. ¹²

Since 1999, we have performed mitral valve repair in 3 patients (including the 2 pediatric patients described here) who had end-stage DCM and peak oxygen consumption less than 10 mL/kg per min. All 3 patients were discharged with improved exercise capacity.

The prognosis of adults with idiopathic DCM is usually poor. In infants and children, DCM often remains stable and sometimes resolves spontaneously. ^13–15 Older age at presentation and lack of improvement in systolic function are associated with adverse outcome. Of the children who do recover, most have definite improvement in left ventricular function within 3 months. Those with progressive dilatation or ventricular arrhythmia are at high risk of early death. Both of our pediatric patients described in this report had experienced progressive ventricular dilatation for approximately 2 years. Early transplantation was definitely indicated.

Although nontransplant cardiac surgery has shown promise in DCM patients, its clinical results in small children have rarely been reported. Our policy, in application to small children who face intractable heart failure and imminent death, has been to use nontransplant cardiac surgery as a bridge to transplantation.

Heart transplantation is severely limited by a shortage of donors. Because of cultural and religious impediments, this donor-recipient discrepancy is particularly serious for small children in our country, where the average wait for a donor heart from a small child is 3 years and 3 months. Among 142 heart transplantations performed in our hospital since 1987, only 4 recipients have been less than 5 years of age. Before the introduction of nontransplant cardiac surgery in our hospital, most of the small children with end-stage DCM died while awaiting transplantation.

Another alternative is the implantation of a left ventricular assist device, which is used for an average of 40 to 100 days. ¹⁶ However, to date, no assist device designed for children smaller than 20 kg is commercially available in our country. Therefore, we had to find some way to support small children with end-stage heart failure.

In conclusion, nontransplant cardiac surgery can improve clinical status and act as a biological bridge, instead of a mechanical bridge, to heart transplantation in small children with end-stage DCM.