Asian Cardiovasc Thorac Ann 2000;8:285-286
© 2000 Asia Publishing EXchange Pte Ltd
Mechanical Circulatory Assist for Pulmonary Artery Obstruction
Yoshio Misawa, MD, PhD,
Katsuo Fuse, MD, PhD,
Shin-ichi Oki, MD
Department of Thoracic and Cardiovascular Surgery
Jichi Medical School
Tochigi, Japan
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For reprint information contact: Yoshio Misawa, MD, PhD Tel: 81 285 44 2111 Fax: 81 285 44 6271 email: tcvmisa{at}jichi.ac.jp Department of Thoracic and Cardiovascular Surgery, Jichi Medical School, Yakushiji 3311-1, Minami-Kawachi, Tochigi 329-0498, Japan.
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Abstract
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A 72-year-old woman underwent replacement of the ascending aorta because of acute aortic dissection. During surgery, the right pulmonary artery was injured. Direct suture closure led to pulmonary artery stenosis with elevated central venous pressure and recurrent ventricular fibrillation. Extracorporeal membrane oxygenation stabilized her hemodynamic condition. She was weaned from the device 6 days later. Pulmonary angiography revealed severe obstruction of the right pulmonary artery but she had no respiratory symptoms thereafter.
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Introduction
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Mechanical circulatory assist devices for intractable heart failure have been developed with increased sophistication and duration of deployment.
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,
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Percutaneous cardio-pulmonary support (PCPS) using extracorporeal mem-brane oxygenation (ECMO) is the most convenient and widely used type of circulatory assist in Japan. It has been applied in circulatory collapse from various causes including acute pulmonary artery embolism.
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Recovery from a right pulmonary artery obstruction after PCPS for 6 days is reported.
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Case Report
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A 72-year-old woman was transferred to our hospital because of acute Stanford type-A aortic dissection. The ascending aorta was replaced with a prosthetic graft under cardiopulmonary bypass (CPB). During weaning from CPB, the proximal right pulmonary artery beneath the ascending aorta was accidentally injured. Bleeding from the pulmonary artery was controlled by direct suture closure. However, weaning from CPB could not be completed because of hemodynamic deterioration with elevated central venous pressure above 15 mm Hg and recurrent ventricular fibrillation when the assisted flow was reduced below 1.5 L•min
–1
. Two hours of circulatory assist failed to allow weaning from CPB. The site of repair was thought to have caused obstruction of the pulmonary artery. It was decided to institute mechanical circulatory assist with ECMO rather than attempt patch plasty of the possibly stenotic pulmonary artery. PCPS was initiated with a Capiox EBS system (Terumo Corp., Tokyo, Japan). Heparin was administered intravenously and the activated clotting time was controlled between 180 and 220 seconds. PCPS flow was initially maintained at 2 to 4 L•min
–1
and gradually reduced. Mechanical circulatory assist was successfully weaned 144 hours later with the patient in a stable hemodynamic condition. A pulmonary angiogram 4 weeks postoperatively revealed obstruction of the proximal right pulmonary artery with a blood perfusion delay in the right lung field (
Figure
1
). The left pulmonary artery was enlarged and blood flow was increased in the left lung field. There were no complications related to PCPS and the patient was discharged without cardiac or respiratory symptoms. She was doing well at 14 months postoperatively.
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Figure 1.
Pulmonary angiogram before discharge from hospital. The right pulmonary artery was stenotic with reduced perfusion in the right lung field and the left pulmonary artery was engorged.
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Discussion
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The PCPS system used in this case (Capiox EBS) is a newly developed mechanical circulatory assist device that we started to use clinically in 1996.
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The system includes a membrane oxygenator and centrifugal pump. The blood-contacting inner surface of the system is coated with heparin, contributing to less heparin administration and longer circulatory assistance. A 15F arterial cannula and a 19F or 21F venous cannula are inserted into the femoral artery and vein. The venous cannula is progressed into the right atrium.
Circulatory collapse caused by massive pulmonary em-bolism or acute reduction of the pulmonary vascular bed by pneumonectomy, is sometimes medically intractable. Kikugawa and colleagues
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described 2 patients who developed acute circulatory collapse after pneumonectomy and were weaned from mechanical circulatory assist after 3 days, suggesting that the unresected pulmonary paren-chyma adapted to the new milieu. In this case, patch plasty of the stenotic pulmonary artery was an option. However, Kikugawa's experience in addition to our own endorsed our decision of ECMO support in this situation.
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Thus, it was expected that ECMO support without patch plasty of the stenotic pulmonary artery would allow the patient's hemodynamic condition to improve. She was successfully weaned from PCPS without either respiratory or circulatory distress, although her right pulmonary artery was still extremely stenotic with a perfusion defect and her left pulmonary vasculature was engorged. This infers that her left lung adapted to the increased blood flow, contributing to a reduction of right ventricular pressure overloading. Acute reduction of the pulmonary vascular bed might induce transient pulmonary hypertension associated with right ventricular failure or arrhythmias, causing circulatory collapse. Thus, both Kikugawa's cases and ours indicate that circulatory collapse induced by acute reduction of the pulmonary vascular bed can be overcome with mechanical circulatory assist such as ECMO.
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References
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Misawa Y, Fuse K, Hasegawa T, Kato M, Hasegawa N. Repair of ischemic cardiac rupture and perioperative management with mechanical circulatory assist. Nippon Kyobu Geka Gakkai Zasshi 1997;45:141–5. (Japanese)[Medline]
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McBride LR, Naunheim KS, Fiore AC, Moroney DA, Swartz MT. Clinical experience with 111 Thoratec ven-tricular assist devices. Ann Thorac Surg
1999; 67
:1233
–9.[Abstract/Free Full Text]
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Kawahito K, Murata S, Ino T, Fuse K. Angioscopic pulmonary embolectomy and ECMO. Ann Thorac Surg
1998; 66
:982
–3.[Free Full Text]
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Misawa Y, Fuse K, Kawahito K, Konishi H. Clinical experience with a new system, "Capiox EBS". Jpn J Artif Organs
1998; 27
:578
–81.
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Kikugawa D, Murakami T, Endoh K, Ishida A, Tabuchi A, Morita I, et al. ECMO is effective in supporting the patients who have cardiopulmonary failure after pneumonectomy. Jpn J Artif Organs
1998; 27
:72
–5.
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Abstract
Introduction
