The authors are solely responsible for the design and conduct of this study, all study analyses, the drafting and editing of the paper and its final contents.
Forty patients (31 M, 9 F) were enrolled in this single center Phase 1 trial beginning in December 2005 following FDA approval (BB-IND-12480). All patients gave written, informed consent. The study was approved by the Institutional Review Boards of Abbott Northwestern Hospital and the University of Minnesota. Although 60 patients were approved for the trial, enrollment was stopped when our institution became a member of the NHLBI Cardiovascular Cell Therapy Research Network (CCTRN) and began enrollment in the TIME Trial
). Eligible patients included those who presented with their first anterior STEMI who underwent successful angioplasty and stenting (PCI) of the LAD coronary artery. Enrolled patients were required to have at least two hours of chest pain and EKG changes consistent with anterior STEMI or new LBBB and an initial ejection fraction < 50% by echocardiography following PCI. Key exclusions included history of CABG or significant co-morbidities. Because the trial focused on enrolling patients at high risk for developing CHF or LV dysfunction, we included patients with cardiac arrest or cardiogenic shock. All patients were screened for the presence of pre-infarction angina prior to their STEMI presentation.
Forty patients consented to participate in the study and were randomized in a 3:1 ratio to 100 million autologous BMCs versus placebo. A 3:1 ratio was utilized to increase our understanding of the safety profile of this therapy and to encourage enrollment based on the limited number of patients approved for the trial. Randomization was based on an algorithm developed by a biostatistician and was performed at the cell therapy facility following preparation of the BMCs. Cell therapy administration occurred when the patients were clinically stable, 3 to 10 days following their PCI and patients were routinely discharged the following day. On the morning of the procedure the patients were lightly sedated and bone marrow aspiration (50–70 ml) was performed at the posterior iliac crest by a hematopathologist. The aspirate was heparinized and transported within one hour to the University of Minnesota Cell Therapy Laboratory. BMCs were isolated by Ficoll density centrifugation (Gallard-Schlessinger; Plainview, NY) at 450g using a COBE 2991 Cell Processor (Gambro BCT; Lakewood Co.). The cell suspension was counted with an automated cell counter and the volume adjusted to obtain a final product of 100 million BMCs with 5% human serum albumin (HSA) in 20 ml. The placebo product was a solution of 0.9% normal saline and 5% HSA in an identical volume. The final product was delivered within 8 hours of the initial aspiration.
Lot release criteria included > 90% viability by trypan blue exclusion, negative gram stain and endotoxin < 5.0 EU/kg. Routine infectious disease testing included anaerobic, aerobic and fungal cultures, and virology assays for detection of HIV, HCV and Hepatitis B. Flow cytometry for measurement of CD34, CD45 and CD133 was performed in all samples.
Patients were returned to the cardiac catheterization laboratory in the afternoon following bone marrow aspiration. Patients were heparinized and a 6 Fr guiding catheter was placed in the left main coronary ostium. LAD stent patency and TIMI 3 flow was confirmed by angiography in all patients. A 3 Fr infusion catheter was positioned in the stented segment (TurboTracker, Boston Scientific Corp.) and the cellular product or placebo was infused at a rate of 1 ml/min over 20-min. Following completion of the infusion, angiography was again performed to confirm normal arterial flow. No patient experienced chest pain or ECG changes during the infusion.
The primary endpoints of this Phase 1 study was safety as assessed by major adverse clinical events (death, repeat target vessel revascularization, recurrent MI, hospitalization for CHF and ICD placement). Although the study was not sufficiently powered, we examined the absolute change in LVEF between baseline and 6 months as assessed by cardiac MRI (cMRI). Secondary end-points included changes in LV end-diastolic (LVEDV) and end-systolic volumes (LVESV).
cMRI measurements were performed at baseline, 3 and 6 months in all patients using a 1.5 T scanning unit (Avanto, Siemens Medical Solutions). All cMRI readers were blinded to treatment randomization. Commercial software was used for calculations of LVEF and end-systolic and -diastolic volumes and myocardial mass. Infarct size was quantified by delayed (20 min), contrast-enhancement with gadolinium (0.2 mmol/kg) using diastolic 2D flash imaging with the TI adjusted to “null” normal myocardium. The entire ventricle was covered with multiple breath-holds using a slice thickness of 5 mm.
Baseline clinical data is expressed as the median and inter-quartile range while cMRI data of LVEF and LV volumes are presented as mean ± SD. Categorical variables were compared using Fischer’s Exact testing while continuous variables were compared using a k-sample median test or Wilcoxin rank-sum test. The change in LVEF over time was analyzed by ANCOVA. The statistical software used for these calculations was STATA/IC 11.0.
This study was supported by the John Dehaan Foundation. Cell processing was supported by the Production Assistance for Cellular Therapies (PACT), N01-HB-37164. Infusion catheters were generously supplied by the Boston Scientific Corporation (Natick, MA).