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Case Reports

Bridge to Recovery With a Thoratec Biventricular Assist Device for Postpartum Cardiomyopathy

Zimmerman, Hannah*; Coelho-Anderson, Romana; Smith, Richard; Nolan, Paul§; Copeland, Jack*

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doi: 10.1097/MAT.0b013e3181e9ac66
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Abstract

Case Report

The patient, a 25-year-old African-American woman, was initially diagnosed with postpartum cardiomyopathy 7 days after spontaneous vaginal delivery of her first child when she became tachycardic, tachypneic, and hypoxic. After 5 months and more than 12 readmissions for congestive heart failure, she was transferred to our institution for further management of her condition. She had been healthy before her pregnancy. The patient noted no complications during the pregnancy. She weighed 91.4 kg, was 172.7-cm tall, and had a body surface area of 2.05 m2.

An admission echocardiogram showed an ejection fraction of 10%–15% and a right ventricular ejection fraction was “decreased.” On physical exam, she had no jugular venous distension but did have an S3 gallop. She was on the following medications: digoxin 0.25 mg daily, furosemide 40 mg daily, lisinopril 5 mg BID, aldactone 25 mg daily, and metoprolol 25 mg BID.

On admission, she had the following: blood gases: pH 7.52, pCO2 40, pO2 74, HCO3 32.7, base excess (BE) 9.0, O2sat 92.7%; Swan Ganz results: pulmonary artery (PA) pressures 54/27, mean 37 mm hemoglobin (hg), mean pulmonary capillary wedge pressure (PCWP) 18 mm Hg, cardiac index 1.1 L/min/m2, systemic vascular resistance 160 dyne sec/cm5, pulmonary vascular resistance 490 dyne sec/cm5, central venous pressure (CVP) 20 mm Hg, stroke volume 21 ml; laboratory values: Na 128 mEq/L, K 3.7 mEq/L, CL 92 mEq/L, CO2 31 mEq/L, blood urea nitrogen (BUN) 11 mg/dl, creatine (Cr) 1.2 mg/dl, glucose 218 mg/dl; the CBC: WBC 10,100 cells/mm3, Hg 11.3, hematocrit (HCT) 35.3%, platelets (plts) 268,000 plts/mm3; and the coagulation result: prothrombin time (PT) 15.3 seconds, international normalized ratio (INR) 1.1 units, partial thromboplastin time (PTT) 31.1 seconds.

She was placed on inotropic therapy with dobutamine 10 μg/kg/min and milrinone 0.3 μg/kg/min. The patient continued to require inotropic therapy. The dobutamine was adjusted to 5 μg/kg/min and the milrinone was increased from 0.5 to 0.7 μg/kg/min. She was also given a continuous infusion of furosemide at 10 mg/h and amiodarone at 1 mg/min.

Thus, she was in cardiogenic shock on maximal medical therapy and a high-dose inotropic therapy. Her heart failure did not improve. After 6 days of progressively declining status in biventricular failure, it was decided to implant a Thoratec Biventricular Assist Device (BiVAD). This device was chosen because it was hoped that she would have native heart recovery because she was an otherwise young, healthy female with no other source for cardiac disease. Once her sternum was divided, it was clear that she had an enlarged, poorly contracting right ventricle. This confirmed us the global dysfunction of her heart and the need for biventricular support. At implantation, we used a left ventricular apex inflow cannula to insure optimal ventricular decompression. On the right side, we used a right atrial right angle cannula. The standard Dacron tube graft outflow end to the side of the great vessels were used. On postoperative day 1, the patient remained on dopamine 3 μg/kg/min, nitroglycerin 3 μg/kg/min, and nitroprusside 1.8 μg/kg/min. She was intubated, sedated, and placed on duodenal feeding with Oxepa. On postoperative day 2, she was febrile to 39°C. She was positive for toxoplasmosis immunoglobulin M (IgM) with a negative immunoglobulin G (IgG) and therefore was started on the following medications: pyrimethamine, folinic acid, and sulfadiazine. The patient was started on dipyridamole and pentoxifylline for anticoagulation therapy according to our protocol.1 The patient had hemorrhagic secretions and subsequently heparin and aspirin were held. On postoperative day 3, the patient was found to have a pericardial tamponade and was taken to the operating room for evacuation of the hematoma. She was extubated on postoperative day 5. On postoperative day 6, the patient was weaned off all inotropic therapy.

On postoperative day 23 from implant of the Thoratec BiVAD, a weaning trial and echocardiogram were performed at bedside. The device was turned down to 40 bpm for 1 minute and the blood pressure was 105/71 and the heart rate was 121. Then, the device was turned down to 20 bpm for 1 minute and the blood pressure and heart rate were 120/76 and 133, respectively. Next, the device was turned off for 5 minutes and the blood pressure remained stable at 114/75 and the heart rate was 127, and the patient remained asymptomatic. The device was turned back on, and the patient was given a boost of dobutamine at 5 μg/kg/min for 48 hours to induce hypertrophy of the cardiac muscle and scheduled for explantation of the device in 48 hours.

In the operating room, an intraoperative transesophageal echocardiogram was performed with the device turned off and the patient on dobutamine at 5 μg/kg/min. The ejection fraction was 50% and aortic and pulmonary valves were normal. The Thoratec BiVAD was explanted without complications and the patient was given milrinone 0.3 μg/kg/min and dobutamine 5 μg/kg/min. The postoperative echocardiogram showed a left ventricular ejection fraction of 60%. The Swan Ganz postexplantation showed the following values: PA pressures of 32/22 with a mean of 26 mm Hg, PCWP 20 mm Hg, CVP 20 mm Hg, cardiac output 4.1 L/min/m2, SVR 1210 dyne sec/cm5, PVR 117 dyne sec/cm5, and stroke volume of 27 ml.

On postoperative day 2 from the explantation, the patient was transferred from the intensive care unit. Her vital signs remained stable. She was weaned off dobutamine on postoperative day 16 from the explantation and discharged on the following heart failure medications: spironolactone 25 mg daily, dipyridamole 100 mg q 8 hours, metoprolol 50 mg daily, aspirin 81 mg daily, KCl 60 mEq BID, lisinopril 2.5 mg daily, and furosemide 60 mg BID. Two days before the patient was discharged, her echocardiogram showed an ejection fraction of 50%–55%, mild mitral regurgitation with mild left atrial enlargement, and mild tricuspid regurgitation with pulmonary artery pressure of 24 mm Hg plus the CVP. There had been improvement in left ventricular function compared with the preimplant study.

The patient was followed in our cardiac transplantation clinic for 5 months with echocardiograms. Figure 1 shows the end systolic view of her left ventricle on admission, and Figure 2 shows end systole just before discharge from the hospital. The patient's symptoms of congestive heart failure completely resolved. She denied shortness of breath and had returned to all activities of daily living and the care for her infant son. At her last clinic visit, the patient remained on the following medications: lisinopril 2.5 mg daily, spironolactone 25 mg daily, dipyridamole 100 mg TID, metoprolol 50 mg daily, aspirin 81 mg daily, furosemide 60 mg BID, KCl 60 mEq BID, and carvedilol 3.125 mg BID. Her last echocardiogram 7 months postexplantation of the device showed a left ventricular ejection fraction of 40%.

Figure 1.
Figure 1.:
End systole by transthoracic echocardiography on admission.
Figure 2.
Figure 2.:
End systole by transthoracic echocardiography just before discharge from the hospital.

Discussion

Mechanical circulatory assist as a bridge to transplantation for the treatment of postpartum cardiomyopathy have been reported with the Novacor2,3 and BiVADs.4 Farrar et al.5 described the largest group. In this study, of the four patients who received a Thoratec VAD for postpartum cardiomyopathy, two required cardiac transplantation.

Our experience in this case is encouraging. The patient has returned to normal functional status and has improved, but the cardiac function was not normal. Many of the patients diagnosed with postpartum cardiomyopathy are young relatively healthy females. Bridge to recovery is an important option that should be considered because it may return the patient to normal function and avoid the complications and limited lifespan associated with heart transplantation. Unfortunately, there are few reports on bridge to recovery in the treatment of postpartum cardiomyopathy. Further study of this area seems warranted.

References

1. Copeland JG, Arabia FA, Tsau PH, et al: Total artificial hearts: Bridge to transplantation. Cardiol Clin 21: 101–113, 2003.
2. Tandler R, Schmid C, Weyand M, et al: Novacor bridge to transplantation in peripartum cardiomyopathy. Eur J Cardiothorac Surg 11: 394–396, 1997.
3. Hovsepian PG, Ganzel B, Sohi GS, et al: Peripartum cardiomyopathy treated with a left ventricular assist device as a bridge to cardiac transplantation. South Med J 82: 527–528, 1989.
4. Lewis R, Mabie WC, Burlew B, et al: Biventricular assist device as a bridge to cardiac transplantation in the treatment for peripartum cardiomyopathy. South Med J 90: 955–958, 1997.
5. Farrar DJ, Holman WR, McBride LR, et al: Long-term follow-up of thoratec ventricular assist device bridge to recovery patients successfully removed from support after recovery of ventricular function. J Heart Lung Transplant 21: 516–521, 2002.
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