Impella LP2.5 vs. IABP in Cardiogenic SHOCK (ISAR-SHOCK)
Impella LP2.5 vs. IABP in Cardiogenic SHOCK (ISAR-SHOCK)
The goal of the trial was to evaluate treatment with an Impella percutaneous left ventricular assist device (LVAD) compared with an intra-aortic balloon pump (IABP) in patients with cardiogenic shock due to acute myocardial infarction (AMI). The Impella device is implanted through a 13 French sheath in the common femoral artery and inserted through the aortic valve into the left ventricle. It provides axial flow to the ascending aorta at a maximum flow rate of 2.5 L/min.
The percutaneous LVAD would be more effective in improving hemodynamic support.
Patients with cardiogenic shock due to AMI were randomized to an Impella LVAD (n = 13) versus an IABP (n = 13). The device was implanted after percutaneous coronary intervention (PCI) was performed.
For as long as the hemodynamic support device was implanted, patients were maintained on continuous heparin infusion to achieve a partial thromboplastin time of 60-80 seconds.
Overall, 26 patients were randomized, and baseline characteristics between the groups were well matched. In the Impella arm, the median age of participants was 65 years, LV ejection fraction was 27%, peak creatine kinase was 3,719, and time from symptoms until randomization was 4.5 hours. The time required to implant the Impella device was 22 minutes versus 14 minutes for the IABP (p = 0.40). PCI was performed in 92% of each group. One patient died in the Impella group prior to receiving the device.
In the Impella arm, cardiac index was 1.71 L/min/m at baseline and 2.20 L/min/m at 30 minutes (change 0.49 L/min/m). In the IABP arm, cardiac index was 1.73 L/min/m at baseline and 1.84 L/min/m at 30 minutes (change 0.11 L/min/m) (p = 0.02 for change in cardiac index with Impella compared with change in cardiac index with IABP; p = 0.18 for comparison of cardiac index between groups). After 30 hours, cardiac index was 2.51 L/min/m in the Impella group versus 2.40 L/min/m in the IABP group.
The mean arterial blood pressure increased by 9.0 mm Hg in the Impella arm versus decreased by 1.2 mm Hg in the IABP group (p = 0.09). The area under the curve for serum lactate during 48 hours was 123 hours · mmol/L versus 180 hours · mmol/L (p = 0.12), and 30-day mortality was 46% versus 46% (p = NS), respectively. The Impella device was used for 25 hours versus 23 hours for the IABP device.
There was one case of acute limb ischemia after the Impella device was removed versus no limb ischemia in the IABP group. The Impella group required transfusion of 2.6 U packed red blood cells versus 1.2 U in the IABP group (p = 0.18).
Among patients with cardiogenic shock due to AMI, the Impella device resulted in a greater change in 30-minute cardiac index compared with the IABP; however, at all measured time points, including 30 minutes and after 30 hours, cardiac index was similar between the groups. Although underpowered for clinical outcomes, 30-day mortality was the same in both groups.
A significant limitation of this trial was the lack of adjudication for major bleeding, which would likely not be trivial due to an indwelling 13 French catheter. This was partly evidenced by the greater need for packed red blood cell transfusion in the Impella group. Another safety signal was noted by the one episode of acute limb ischemia in the Impella group. Future studies will need to examine the clinical efficacy and safety of this device.
Study Design
Randomized. Parallel.
Description
The goal of the trial was to evaluate treatment with an Impella percutaneous left ventricular assist device (LVAD) compared with an intra-aortic balloon pump (IABP) in patients with cardiogenic shock due to acute myocardial infarction (AMI). The Impella device is implanted through a 13 French sheath in the common femoral artery and inserted through the aortic valve into the left ventricle. It provides axial flow to the ascending aorta at a maximum flow rate of 2.5 L/min.
Hypothesis
The percutaneous LVAD would be more effective in improving hemodynamic support.
Drugs/Procedures Used
Patients with cardiogenic shock due to AMI were randomized to an Impella LVAD (n = 13) versus an IABP (n = 13). The device was implanted after percutaneous coronary intervention (PCI) was performed.
Concomitant Medications
For as long as the hemodynamic support device was implanted, patients were maintained on continuous heparin infusion to achieve a partial thromboplastin time of 60-80 seconds.
Principal Findings
Overall, 26 patients were randomized, and baseline characteristics between the groups were well matched. In the Impella arm, the median age of participants was 65 years, LV ejection fraction was 27%, peak creatine kinase was 3,719, and time from symptoms until randomization was 4.5 hours. The time required to implant the Impella device was 22 minutes versus 14 minutes for the IABP (p = 0.40). PCI was performed in 92% of each group. One patient died in the Impella group prior to receiving the device.
In the Impella arm, cardiac index was 1.71 L/min/m at baseline and 2.20 L/min/m at 30 minutes (change 0.49 L/min/m). In the IABP arm, cardiac index was 1.73 L/min/m at baseline and 1.84 L/min/m at 30 minutes (change 0.11 L/min/m) (p = 0.02 for change in cardiac index with Impella compared with change in cardiac index with IABP; p = 0.18 for comparison of cardiac index between groups). After 30 hours, cardiac index was 2.51 L/min/m in the Impella group versus 2.40 L/min/m in the IABP group.
The mean arterial blood pressure increased by 9.0 mm Hg in the Impella arm versus decreased by 1.2 mm Hg in the IABP group (p = 0.09). The area under the curve for serum lactate during 48 hours was 123 hours · mmol/L versus 180 hours · mmol/L (p = 0.12), and 30-day mortality was 46% versus 46% (p = NS), respectively. The Impella device was used for 25 hours versus 23 hours for the IABP device.
There was one case of acute limb ischemia after the Impella device was removed versus no limb ischemia in the IABP group. The Impella group required transfusion of 2.6 U packed red blood cells versus 1.2 U in the IABP group (p = 0.18).
Interpretation
Among patients with cardiogenic shock due to AMI, the Impella device resulted in a greater change in 30-minute cardiac index compared with the IABP; however, at all measured time points, including 30 minutes and after 30 hours, cardiac index was similar between the groups. Although underpowered for clinical outcomes, 30-day mortality was the same in both groups.
A significant limitation of this trial was the lack of adjudication for major bleeding, which would likely not be trivial due to an indwelling 13 French catheter. This was partly evidenced by the greater need for packed red blood cell transfusion in the Impella group. Another safety signal was noted by the one episode of acute limb ischemia in the Impella group. Future studies will need to examine the clinical efficacy and safety of this device.
Conditions
Cardiogenic shock
Coronary heart disease / Acute MI
Coronary heart disease / Acute MI / Heart Failure
Study Design
Randomized. Parallel.
Patients Enrolled: 26
Mean Follow-Up: 30 days
Mean Patient Age: Median 66 years
% Female: 27
Mean Ejection Fraction: 27%
Primary Endpoints
Change in cardiac index from baseline to 30 minutes after device implantation
Secondary Endpoints
Change in lactic acidosis
Hemolysis
Mortality at 30 days
Patient Population
Patients with AMI within 48 hours and cardiogenic shock
Cardiogenic shock was defined as systolic blood pressure <90 mm Hg and heart rate >90 bpm or the need for inotropic drugs. Patients also needed evidence of end-organ hypoperfusion (cool extremities, low urine output, low cardiac index, or elevated pulmonary capillary wedge pressure).
Exclusions:
Age <18 years
More than 30 minutes of resuscitation
Hypertrophic obstructive cardiomyopathy
Thrombus in the left ventricle
Treatment with an IABP
Severe valvular heart disease or a mechanical heart valve
Mechanical complication of AMI
Sepsis
Cerebral disease
Severe bleeding
Pulmonary embolus
Heparin allergy or coagulopath
Inclusion in another clinical trial
Source...