心原性ショックにおいて大動脈内バルーンパンピングの生存率に関する有益性はない

IABP-SHOCK II study：最も広く使用されている機械的補助循環装置は心原性ショック患者の死亡率を改善しなかった
IABP-SHOCK II study: Most widely used mechanical support device fails to improve mortality rate in cardiogenic shock patients
2012年European Society of Cardiology学会で、心原性ショックに対する大動脈内バルーンパンピング（IABP）の使用による有益性が認められないことが報告された。国際的ガイドラインでは心原性ショック患者に対するIABPの使用を推奨している。しかし、循環器医らはその有効性を完全には認めていないため、現在IABPはショック患者の25～40%にしか使用されていない。IABP-SHOCK IIトライアル―心原性ショックに対して施行されたトライアルの中で最も大規模―は、ドイツの37施設で登録された患者600人をIABPまたは従来通り の最良の薬物療法のみの群に無作為に割り付けた。その結果、30日間の死亡率はIABP群において標準治療を施行されたコントロール群と比較し低下しなかった。様々なサブグループにおいても評価を行ったがIABPの明らかな有益性は認められなかった。同様に、IABPは血圧を改善せず、集中治療室におけ る治療時間も短縮せず、処方薬の使用期間または使用用量も減少させず、臓器灌流も改善しなかった。一方、トライアルの結果、IABPは合併症を引き起こすことはなく安全な装置であることが示された。この結果は同時にNew England Journal of Medicineに掲載された。
Full Text

A balloon pump inserted in the aorta is currently the most widely used support device in the treatment of cardiogenic shock and, since its introduction in 1968, has been used in several million people. However, there is still only limited evidence that the intraaortic balloon pump (IABP), one of the oldest medical devices in cardiology, is actually beneficial for the patient. Only a few registry studies and clinical trials have shown that the IABP can improve blood pressure and the perfusion of the coronary arteries.

Based on these studies, international guidelines recommend the use of an IABP in patients with cardiogenic shock. However, because cardiologists are not entirely convinced of its efficacy, an IABP is currently used in only 25-40% of shock patients. It was for these reasons that the IABP-SHOCK II trial was designed, aiming to show that the IABP can improve mortality if used in conjunction with optimal medical therapy and early reopening of the infarct-related artery.

Approximately 5-10% of patients after a myocardial infarction experience the complication of cardiogenic shock. In Europe around 60-70,000 patients are diagnosed with cardiogenic shock each year. In the past decade mortality related to cardiogenic shock has been reduced, mainly by early reopening of the infarct-affected artery by early balloon inflation. Nevertheless, the mortality rate in these patients is still extremely high, with approximately 50% dying within the first 30 days.

The IABP-SHOCK II trial - the largest trial ever performed in cardiogenic shock - randomized 600 patients enrolled in 37 centers in Germany to either an IABP or conventional optimal medical treatment alone. The hypothesis tested was that the IABP could reduce the rate of mortality within 30 days.

However, the study found no reduction in 30-day mortality rate in the IABP group when compared to the control group having standard care alone. Several subgroups were also evaluated and here too there was no clear benefit found for the IABP.

Similarly, the IABP showed no improvement in blood pressure, no reduction in treatment time in the intensive care unit, no decrease in the duration or dose of drugs prescribed, and no improvement in organ perfusion. On the other hand, the trial results showed that the IABP did not induce complications, and was shown to be a safe device.

Presenting the results, Professor Holger Thiele from the University of Leipzig Heart Centre in Germany said: "This large multicenter trial was unable to show a benefit for the currently most widely used mechanical support device in cardiogenic shock."

Because of its importance, the trial was supported by the German Research Foundation, the German Heart Research Foundation, the German Cardiac Society, the Arbeitsgemeinschaft Leitende Kardiologische Krankenhausärzte, and also partly funded by unrestricted grants from Maquet Cardiopulmonary AG, Hirrlingen, Germany and Teleflex Medical, Everett, MA, USA.