Abstract
Objectives
This study aimed to report the in-hospital and 30-day event rates in patients undergoing non-emergent, high-risk percutaneous coronary intervention (PCI) and to evaluate whether the Impella Recover LP 2.5 device (Abiomed, Danvers, MA) demonstrates superiority over intra-aortic balloon pump (IABP) in the Protect II (A Prospective Feasibility Trial Investigating the Use of the Impella Recover LP 2.5 System in Patients Undergoing High Risk Percutaneous Coronary Intervention) study.
Background
Patients undergoing non-emergent, high-risk PCI are often treated with prophylactic IABP for hemodynamic support.
Methods
A cohort of 85 patients who met the inclusion/exclusion criteria of the Protect II study was included in this retrospective analysis. High-risk PCI was defined as intervention to the last patent coronary conduit or to an unprotected left main or in a patient with three-vessel disease with an ejection fraction of ≤35%. Patients with ST-segment elevation myocardial infarction (MI), cardiac arrest within 24 h, or cardiogenic shock were excluded. The primary end point was the composite of death, MI, stroke, transient ischemic attack, repeat revascularization, renal failure, severe hypotension, cardiopulmonary resuscitation, ventricular arrhythmias requiring intervention, and angiographic failure at 30 days.
Results
The overall in-hospital and 30-day event rates were low (15.3% and 21.3%, respectively) with a low major vascular complication rate (5.9%). Therefore, for the Impella Recover LP 2.5 device to demonstrate superiority over IABP with a treatment effect of 33.3% and 80% power, the Protect II trial will require a total of 908 patients. With the current sample size of 654 patients, the Protect II trial is underpowered, with only 66% power.
Conclusion
These data question the clinical benefit of the Protect II study, which is evaluating the relatively high-profile Impella LP 2.5 device over IABP for this high-risk population.
1
Introduction
Intra-aortic balloon pump (IABP) is commonly used for hemodynamic support in patients with cardiogenic shock, in patients with post-myocardial infarction (MI) complications, and for complications during percutaneous coronary intervention (PCI) . Although controversial, the prophylactic use of IABP in patients undergoing high-risk PCI has been reported as effective in numerous registries . We reported previously that a study of 68 patients subject to high-risk PCI and who received prophylactic IABP support had favorable outcomes compared to those who required IABP for intraprocedural complications . Preliminary clinical experience shows that the Impella Recover LP 2.5 device (Abiomed, Danvers, MA) potentially enables immediate and sustained unloading of the left ventricle while increasing the overall systemic cardiac output and supports patients with cardiogenic shock. Further, it was suggested that the device could be potentially useful in high-risk PCI . The Impella device is currently being tested against IABP in the Protect II (A Prospective Feasibility Trial Investigating the Use of the Impella Recover LP 2.5 System in Patients Undergoing High Risk Percutaneous Coronary Intervention) study to seek Food and Drug Administration approval for hemodynamic support during high-risk PCI. The aim of this analysis is to detect the event rates in a population subjected to high-risk PCI with prophylactic support of IABP using the same inclusion and exclusion criteria as the Protect II trial in order to predict whether the study can meet its primary end points.
2
Methods
Among our general PCI population who had IABP for non-emergent high-risk PCI, a cohort of 85 patients was identified as receiving prophylactic IABP support for high-risk PCI and who met the inclusion/exclusion criteria of the Protect II study. The major inclusion criteria ( Fig. 1 ) included patients 18–90 years old with (1) ejection fraction ≤35% and ≥1 of the following criteria: intervention on the last patent coronary conduit or to an unprotected left main coronary artery; and (2) ejection fraction ≤30% and intervention on patient presenting with triple-vessel disease defined as ≥1 significant stenosis (≥50%) in all three major epicardial territories. Major exclusion criteria included patients with ST-segment elevation MI (STEMI) within 24 h, pre-procedure cardiac arrest within 24 h of enrollment requiring cardiopulmonary resuscitation, and subject is in cardiogenic shock defined as cardiac index <2.2 L/min/m 2 and pulmonary capillary wedge pressure >15 mm Hg and hypotension (systolic blood pressure <90 mm Hg for >30 min or the need for supportive measures to maintain a systolic blood pressure of ≥90 mm Hg), end-organ hypoperfusion (cool extremities or a urine output of <30 ml/h), and a mural thrombus in the left ventricle. Patients with mechanical aortic valve or heart constrictive devices, moderate to severe aortic stenosis or aortic insufficiency, renal or liver failure (creatinine >4 mg/dl or international normalized ratio ≥2, respectively), abnormalities of the aorta (aneurysms, tortuosity, and calcification), allergies to certain anticoagulation or antiplatelet medications, coagulopathy, and heparin-induced thrombocytopenia were excluded as well.
