LVADs保護心臟移植候選病患的腎臟功能


  April 10, 2008(波士頓) —哈佛以及麻州綜合醫院的研究人員在國際心肺移植學會第28屆年會與科學會議中報告指出,末期心臟衰竭的心臟移植候選病患可以藉由使用左心室輔助器(left ventricular assist devices,LVADs)獲得心臟支持以及腎臟保護。
  
  麻州綜合醫院心臟科與哈佛醫學院的Stephanie C. Ennis醫師報告指出,在一篇比較「單純接受移植器官之病患」與「接受LVAD植入物作為移植架接橋之病患」的研究中,接受LVAD植入之病患的推估腎絲球廓清率(eGFR)在一個月內有明顯改善,且維持到移植後6個月,而僅接受移植器官之病患的 eGFR 則沒有改變。
  
  Ennis女士表示,有許多研究指出,惡化的腎功能以及漸漸衰退的心臟會帶來不佳預後,增加住院期間以及高死亡率;心衰竭治療,特別是使用利尿劑者,會導致腎功能惡化。
  
  未參與此研究的英國Harefield醫院的Nicholas Banner醫師表示,腎功能衰退是末期心臟衰竭的常見共病症。
  
  他在Medscape Transplantation的訪問中表示,接受心臟移植的病患,腎功能幾乎都不好,這一部分和他們在移植之前的循環狀態有關,因為心臟衰弱,這些病患血壓低且心輸出也低,而腎臟對輸注之改變相當敏感。
  
  此外,心臟衰竭也會發生神經荷爾蒙活化—特別是增加交感神經活性 — 而惡化腎血流和腎功能,有些用來治療心臟衰竭的藥物,如血管收縮素轉化酶抑制劑(Angiotensin converting enzyme inhibitor/ACEI)、血管收縮素接受器阻斷劑 (angiotensin receptor blockers/ ARB)、以及移植後的免疫抑制劑,如calcineurin抑制劑也會造成此現象。
  
  Ennis女士等人檢測用作移植物架接橋的LVADs是否可在移植後的期間仍提供病患循環支持以及腎臟保護。
  
  因此,他們評估了在2005年7月至2007年3月間於麻州綜合醫院接受心臟移植之病患的腎功能;他們使用eGFR 測量腎功能是否健康,計算公式依據腎臟疾病校正飲食公式(Modification of Diet in Renal Disease formula): eGFR (mL/min/1.73 m2) = 186 × creatine-1.154 × 年紀-0.203 × 1.21(病患為黑人時)且× 0.742(病患為女性時)。
  
  研究者共研究33名病患,其中17名 (13名男性以及4名女性)接受 LVAD植入,另外16名 (14名男性以及2名女性)則沒有;兩組之間的年紀(49 ± 13 vs. 56 ± 10 歲; P = .08)或者開始時的eGFR (54 ± 20 vs. 51 ± 14 mL/min; P = .6)都沒有顯著不同。
  
  作者發現,植入LVAD後1個月,LVAD組的eGFR有明顯改善,從開始時的54 mL/min 改善到1個月時的79 mL/min;此組的 eGFR在心臟移植之後6 個月仍維持;而在未使用LVAD組的eGFR ,在移植之後6個月與開始時相比,並無明顯改變;兩組在移植後6個月出現明顯差異,接受LVAD的病患為 78 ± 19 mL/min,單純移植心臟組為 53 ± 17 mL/min (差異P = .0003)。
  
  Ennis女士表示,使用LVADs 作為移植物架接橋可以改善腎功能且在移植初期持續;這些發現是否有長期改善,則需要以更大型的研究進行更長的追蹤。
  
  Banner醫師表示,接受VAD的病患可以是穩定的, 可以通過恢復與復健期,改善腎功能,之後以較佳的生理狀態接受移植,因此可以合理預期他們會有比較好的腎功能。
  
  Ennis女士等人指出,他們的研究限制為樣本小、回溯設計、追蹤期間短。
  
  Ennis女士和 Banner醫師宣告無相關資金往來。
  
  國際心肺移植學會第28屆年會與科學會議:摘要6。發表於2008年4月9日。

LVADs Protect Renal Function i

By Neil Osterweil
Medscape Medical News

April 10, 2008 (Boston) — Heart transplant candidates in end-stage heart failure can get both cardiac support and renal protection from the use of left ventricular assist devices (LVADs), reported Harvard and Massachusetts General Hospital researchers here at the International Society for Heart and Lung Transplantation 28th Annual Meeting and Scientific Sessions.

In a study comparing heart transplant recipients who received an LVAD implant as a bridge to transplant with those who received the graft alone, the estimated glomerular filtration rate (eGFR) was significantly improved within a month of the LVAD implant and through 6 months posttransplant, whereas the eGFR among graft-only patients remained unchanged, reported Stephanie C. Ennis, ANP, from the Division of Cardiology at Massachusetts General Hospital and the Harvard Medical School, both in Boston.

"Several studies have demonstrated that worsening renal functioning and progressive heart failure carry a poor prognosis, including increased length of stay and high mortality. Heart failure therapy, especially the use of diuretics, can lead to worsening renal function," said Ms. Ennis.

Declining renal function is a common comorbidity of end-stage heart failure, agreed Nicholas Banner, MD, from the Harefield Hospital in Harefield, Middlesex, United Kingdom, who was not involved in the study.

"For patients undergoing heart transplantation, renal dysfunction is almost universal," he said in an interview with Medscape Transplantation, "and this is partly related to their circulatory state before transplantation. With a very weak heart, the patient's going to have low blood pressure and low cardiac output, and the kidneys are very sensitive to changes in perfusion."

In addition, neurohormonal activation that occurs in heart failure — particularly increased sympathetic nerve activity — can also adversely affect renal blood flow and renal function, as can some drugs used to treat heart failure, such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and posttransplant immunosuppressants such as calcineurin inhibitors, Dr. Banner said.

Ms. Ennis and colleagues tested whether LVADs, when used as bridges to transplants, could afford patients both circulatory support and renal protection extending into the posttransplant period.

To do this, they evaluated renal function among patients undergoing cardiac transplantation at Massachusetts General Hospital from July 2005 through March 2007. They used eGFR as a measure of renal health, calculating it according to the Modification of Diet in Renal Disease formula: eGFR (mL/min/1.73 m2) = 186 × creatine−1.154 × age−0.203 × 1.21 if the patient is black and × 0.742 if the patient is female.

The researchers looked at a total of 33 patients, of whom 17 (13 men and 4 women) had received an LVAD implant and 16 (14 men and 2 women) had not. There were no significant between-group differences in age (49 ± 13 vs 56 ± 10 years; P = .08) or eGFR at baseline (54 ± 20 vs 51 ± 14 mL/min; P = .6).

The authors found that 1 month after LVAD implant, there was significant improvement in eGFR in the LVAD group, with a change from about 54 mL/min at baseline to about 79 mL/minute at 1 month. The eGFR in this group was similar out to 6 months postcardiac transplantation; there was no significant change from baseline to 6 months posttransplant in the no-LVAD group The differences between the groups were significant at 6 months after transplant, at 78 ± 19 mL/min in the LVAD recipients vs 53 ± 17 mL/min in the heart graft–only group (P for difference = .0003)

"The use of LVADs as a bridge to transplant may provide improvement in the renal function that is sustained in the early transplant period," Ms. Ennis said. "Whether these findings translate into improved longer-term outcomes needs to be tested in larger studies with longer follow-up."

Dr. Banner said, "A patient who has been stabilized with a VAD, and who has gone through a period of recuperation and rehabilitation, normally their kidney function improves, so they are then going into the transplant in a better physiological state, and it would be reasonable to expect that they would have better early kidney function."

Ms. Ennis and colleagues acknowledged that their study was limited by its small sample size, retrospective design, and relatively short follow-up.

Ms. Ennis and Dr. Banner have disclosed no relevant financial relationships.

International Society for Heart and Lung Transplantation 28th Annual Meeting and Scientific Sessions: Abstract 6. Presented April 9, 2008.

J Heart Lung Transplant. 2008;27(2 suppl):S62.

    
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