Transcatheter Aortic Valve Replacement Outcomes in End-Stage Renal Disease Patients on Hemodialysis Requiring Midodrine.

Background: Patients with dialysis-dependent end-stage renal disease (ESRD) taking midodrine may be at high risk for poor outcomes following transcatheter aortic valve replacement (TAVR). We evaluated dialysis-dependent ESRD patients taking midodrine. Methods: We conducted a retrospective analysis of non-clinical trial TAVR patients from February 2012 to December 2020 from 11 facilities in a Western US health system. Patient groups included ESRD patients on midodrine before TAVR (ESRD [+M]), ESRD patients without midodrine (ESRD [-M]), and non-ESRD patients. The endpoints of 30-day and 1-year mortality were represented by Kaplan-Meier survival estimator and compared by log-rank test. Results: Forty-five ESRD (+M), 216 ESRD (-M), and 6898 non-ESRD patients were included. ESRD patients had more comorbid conditions, despite no significant difference in predicted Society of Thoracic Surgeons mortality risk between ESRD (+M) and ESRD (-M) (8.7% vs. 9.2%, p = 0.491). Thirty-day mortality was significantly higher for ESRD (+M) patients vs. ESRD (-M) patients (20.1% vs. 5.6%, p = 0.001) and for ESRD (+M) vs. non-ESRD patients (2.5%, p < 0.001). One-year mortality trended higher for ESRD (+M) vs. ESRD (-M) patients (41.9% vs. 29.8%, p = 0.07), and was significantly higher for ESRD (+M) vs. non-ESRD patients (10.7%, p < 0.001). Compared to ESRD (-M), ESRD (+M) patients had a higher incidence of 30-day stroke (6.7% vs. 1.4%, p = 0.033), 30-day vascular complications (6.7% vs. 0.9%, p = 0.011), and a lower rate of discharge to home (62.2% vs. 84.7%, p < 0.001). In contrast, ESRD (-M) patients had no significant differences from non-ESRD patients for these outcomes. Conclusions: Our experience suggests ESRD patients on midodrine are a higher acuity population with worse survival after TAVR, compared to ESRD patients not on midodrine. These findings may help with risk stratification for ESRD patients undergoing TAVR.

Safety and efficiency of percutaneous coronary intervention using a standardised optical coherence tomography workflow.

BACKGROUND: While intravascular imaging guidance during percutaneous coronary intervention (PCI) improves outcomes, routine intravascular imaging usage remains low, in part due to perceived inefficiency and safety concerns.  Aims: The LightLab (LL) Initiative was designed to evaluate whether implementing a standardised optical coherence tomography (OCT) workflow impacts PCI safety metrics and procedural efficiency. METHODS: In this multicentre, prospective, observational study, PCI procedural data were collected over 2 years from 45 physicians at 17 US centres. OCT-guided PCI incorporating the LL workflow (N=264), a structured algorithm using routine pre- and post-PCI OCT imaging, was compared with baseline angiography-only PCI (angio) (N=428). Propensity score analysis identified 207 matched procedures. Outcomes included procedure time, radiation exposure, contrast volume, device utilisation, and treatment strategy. RESULTS: Compared with angiography alone, LL workflow OCT-guided PCI increased the median procedural time by 9 minutes but reduced vessel preparation time (2 min LL workflow vs 3 min angio; p<0.001) and resulted in less unplanned additional treatment (4% LL workflow vs 10% angio; p=0.01). With LL workflow OCT guidance, fewer cineangiography views were needed compared to angiography guidance, leading to decreased radiation exposure (1,133 mGy LL workflow vs 1,269 mGy angio; p=0.02), with no difference in contrast utilisation between groups (p=0.28). Furthermore, LL workflow OCT guidance resulted in fewer predilatation balloons and stents being used, more direct stent placement, and greater stent post-dilatation than angiography-guided PCI. CONCLUSIONS: The incorporation of a standardised pre- and post-PCI OCT imaging workflow improves procedural efficiency and safety metrics, at a cost of a modestly longer procedure time.

Vasculogenic properties of adventitial Sca-1+CD45+ progenitor cells in mice: a potential source of vasa vasorum in atherosclerosis.

The cellular origins of vasa vasorum are ill-defined and may involve circulating or local progenitor cells. We previously discovered that murine aortic adventitia contains Sca-1+CD45+ progenitors that produce macrophages. Here we investigated whether they are also vasculogenic. In aortas of C57BL/6 mice, Sca-1+CD45+ cells were localised to adventitia and lacked surface expression of endothelial markers (<1% for CD31, CD144, TIE-2). In contrast, they did show expression of CD31, CD144, TIE-2 and VEGFR2 in atherosclerotic ApoE-/- aortas. Although Sca-1+CD45+ cells from C57BL/6 aorta did not express CD31, they formed CD31+ colonies in endothelial differentiation media and produced interconnecting vascular-like cords in Matrigel that contained both endothelial cells and a small population of macrophages, which were located at branch points. Transfer of aortic Sca-1+CD45+ cells generated endothelial cells and neovessels de novo in a hindlimb model of ischaemia and resulted in a 50% increase in perfusion compared to cell-free control. Similarly, their injection into the carotid adventitia of ApoE-/- mice produced donor-derived adventitial and peri-adventitial microvessels after atherogenic diet, suggestive of newly formed vasa vasorum. These findings show that beyond its content of macrophage progenitors, adventitial Sca-1+CD45+ cells are also vasculogenic and may be a source of vasa vasorum during atherogenesis.

Effect of Preprocedural Thrombocytopenia on Prognosis After Percutaneous Coronary Intervention.

OBJECTIVE: To assess early and late outcomes, including bleeding, in patients with thrombocytopenia undergoing percutaneous coronary intervention (PCI). PATIENTS AND METHODS: We performed a retrospective single-center study of patients with preprocedural thrombocytopenia (platelet count ≤100,000/µL; n=204) undergoing PCI between 2003 and 2015. Inhospital and late outcomes were compared with those of a matched control group without thrombocytopenia (n=1281). RESULTS: The most common causes of thrombocytopenia were liver disease, immune-mediated disease, and hematologic malignant neoplasms. Inhospital bleeding events after PCI were similar in patients with thrombocytopenia and matched controls (24 of 146 [16.4%] vs 179 of 1281 [14.0%]; P=.40) and were largely classified as minor using the Bleeding Academic Research Consortium (BARC) classification (89% BARC 1 or 2). There was no significant difference in inhospital death (4 of 146 [2.7%] vs 71 of 1281 [2.0%]; P=.56), but patients with thrombocytopenia had higher rates of platelet and red blood cell transfusion (18 of 146 [12.3%] vs 93 of 1281 [7.2%]; P=.05). During long-term follow-up, Kaplan-Meier estimated rates of bleeding events (BARC ≥2) were higher for thrombocytopenia (at 5 years, 7.9% vs 3.6%; P=.03). Patients with thrombocytopenia had a similar risk of long-term cardiac mortality, but significantly higher rates of noncardiac mortality (at 5 years, 28% vs 21%; P=.02). CONCLUSION: This study suggests that short-term outcomes after PCI in patients with thrombocytopenia were favorable. On long-term follow-up, thrombocytopenia was associated with a higher risk of long-term noncardiac mortality and bleeding.

Low-Dose Gamma Irradiation of Decellularized Heart Valves Results in Tissue Injury In Vitro and In Vivo.

BACKGROUND: Decellularized heart valves are emerging as a potential alternative to current bioprostheses for valve replacement. Whereas techniques of decellularization have been thoroughly examined, terminal sterilization techniques have not received the same scrutiny. METHODS: This study evaluated low-dose gamma irradiation as a sterilization method for decellularized heart valves. Incubation of valves and transmission electron microscopy evaluation after different doses of gamma irradiation were used to determine the optimal dose of gamma irradiation. Quantitative evaluation of mechanical properties was done by tensile mechanical testing of isolated cusps. Sterilized decellularized heart valves were tested in a sheep model (n = 3 [1 at 1,500 Gy and 2 at 3,000 Gy]) of pulmonary valve replacement. RESULTS: Valves sterilized with gamma radiation between 1,000 Gy and 3,000 Gy were found to be optimal with in vitro testing. However, in vivo testing showed deteriorating valve function within 2 months. On explant, the valve with 1,500 Gy gamma irradiation showed signs of endocarditis with neutrophils on hematoxylin and eosin staining, and positive gram stain resembling streptococcus infection. The 3,000 Gy valves had no evidence of infection, but the hematoxylin and eosin staining showed evidence of wound remodeling with macrophages and fibroblasts. Tensile strength testing showed decreased strength (0 Gy: 2.53 ± 0.98 MPa, 1,500 Gy: 2.03 ± 1.23 MPa, and 3,000 Gy: 1.26 ± 0.90 MPa) with increasing levels of irradiation. CONCLUSIONS: Low-dose gamma irradiation does not maintain the mechanical integrity of valves, and the balance between sterilization and damage may not be able to be achieved with gamma irradiation. Other methods of terminal sterilization must be pursued and evaluated.

Prediction of Cardiac and Noncardiac Mortality After Percutaneous Coronary Intervention.

BACKGROUND: Current risk models for predicting long-term mortality after percutaneous coronary intervention are restricted to all-cause mortality. We sought to develop novel risk models for the prediction of cardiac and noncardiac mortality after percutaneous coronary intervention. METHODS AND RESULTS: We retrospectively evaluated patients who underwent index percutaneous coronary intervention at Mayo Clinic from 2003 to 2008. Long-term deaths were ascertained through scheduled prospective surveillance. Cause of death was determined via telephone interviews, medical records, and autopsy reports. Fine and Gray extension of Cox proportional hazards models was used to model cause-specific cumulative incidence. Candidate variables and interactions were chosen a priori, without variable selection methods. Resulting models were mapped to an integer-based risk score. The study comprised 6636 patients followed up over a median of 62 months (25th, 75th percentiles: 45, 77 months). There were 1488 deaths, 518 (35%) cardiac, 938 (63%) noncardiac, and 32 (2%) unknown. The 5-year predicted cardiac mortality ranged from 0.6% to 97%, with a corrected c-statistic of 0.82. Risk factors for cardiac death included age, body mass index, ejection fraction, and history of congestive heart failure. The integer score for noncardiac death included age, medicine index, body mass index, current smoker, noncardiac Charlson index and cardiac Charlson index, and accommodated significant age-based interactions for smoking and the 2 Charlson indices. Predicted noncardiac mortality at 5 years ranged from 0.2% to 81%, with a corrected c-statistic of 0.77. CONCLUSIONS: We report novel risk models to predict cardiac and noncardiac long-term mortality after percutaneous coronary intervention.

Incidence of symptomatic venous thromboembolism in patients with hemophilia undergoing joint replacement surgery: a retrospective study.

INTRODUCTION: Venous thromboembolism (VTE) is a recognized complication after joint replacement surgery, and prophylaxis is routinely used in patients without bleeding disorders. However, for patients with hemophilia, pharmacologic prophylaxis is highly variable and controversial because of the inherent bleeding risk. AIM: To review our institutional experience with outcomes of total knee or hip arthroplasty with regard to symptomatic VTE and use of VTE prophylaxis in patients with hemophilia and without inhibitors. METHODS: We reviewed records of 42 consecutive patients with hemophilia A or B who underwent 71 hip or knee replacements over a 39-year period. We also reviewed the literature to estimate the incidence of VTE after arthroplasty in the hemophilia population. RESULTS: All patients used compression stockings for up to 6weeks after surgery; additionally, 6 cases (10.5%; 57 with available data) used sequential intermittent compression devices and 2 (2.8%) postoperatively received low-molecular-weight heparin. One patient (1.4%) who received low-molecular-weight heparin had a symptomatic, lower-extremity, deep venous thrombosis 10days after hip replacement for traumatic fracture. None of the other 70 surgical cases had symptomatic VTE within 3months after the procedure. Analysis of pooled data from published series of hemophilia patients undergoing arthroplasty showed an estimated incidence of symptomatic VTE of 0.5%. CONCLUSION: Our study suggests that in patients with hemophilia, joint replacement surgery can be performed safely without routine pharmacologic VTE prophylaxis and without increasing risk of thromboembolic events. Pharmacologic VTE prophylaxis may be considered in select patients with known additional risk factors for VTE.

Osteogenic monocytes within the coronary circulation and their association with plaque vulnerability in patients with early atherosclerosis.

OBJECTIVES: This study tests the hypothesis that circulating mononuclear cells expressing osteocalcin (OCN) and bone alkaline phosphatase (BAP) are associated with distinct plaque tissue components in patients with early coronary atherosclerosis. BACKGROUND: Plaque characteristics implying vulnerability develop at the earliest stage of coronary atherosclerosis. Increasing evidence indicates that cells from the myeloid lineage might serve as important mediators of destabilization. Plaque burden and its components were assessed regarding their relationship to monocytes carrying both pro-inflammatory (CD14) and osteogenic surface markers OCN and BAP. METHODS: Twenty-three patients with angiographically non-obstructive coronary artery disease underwent coronary endothelial function assessment and virtual histology-intravascular ultrasound of the left coronary artery. Plaque composition was characterized in the total segment (TS) and in the target lesion (TL) containing the highest amount of plaque burden. Blood samples were collected simultaneously from the aorta and the coronary sinus. Circulating cell counts were then identified from each sample and a gradient across the coronary circulation was determined. RESULTS: Circulating CD14+/BAP+/OCN+ monocytes correlate with the extent of necrotic core and calcification (r=0.53, p=0.010; r=0.55, p=0.006, respectively). Importantly, coronary retention of CD14+/OCN+ cells also correlates with the amount of necrotic core and calcification (r=0.61, p=0.003; r=0.61, p=0.003) respectively. CONCLUSIONS: Our study links CD14+/BAP+/OCN+ monocytes to the pathologic remodeling of the coronary circulation and therefore associates these cells with plaque destabilization in patients with early coronary atherosclerosis.

Drug delivery in aortic valve tissue engineering.

Over the last 50 years medicine and technology have progressed to the point where it has become commonplace to safely replace damaged or diseased heart valves with mechanical and biological prostheses. Despite the advancements in technology current valve substitutes continue to have significant limitations with regards to thrombogenicity, durability, and inability to grow or remodel. In an attempt to overcome the limitations of currently available valve prosthesis, heart valve tissue engineering has emerged as a promising technique to produce biological valve substitutes. Currently, the field of tissue engineering is focused on delivering complex matrices which include scaffolds and cells separately or together to the damaged site. Additional functional enhancement of the matrices by exposing encoded biological signals to their residing cells in a controlled manner has the potential to augment the tissue engineering approach. This review provides an overview of the delivery of biological reagents to guide and regulate heart valve tissue engineering.

An update on stem cell therapies for acute coronary syndrome.

Well into the second decade since its conception, cell transplantation continues to undergo intensive evaluation for the treatment of myocardial infarction. At a mechanistic level, its objectives remain to replace lost cardiac cell mass with new functioning cardiomyocytes and vascular cells, thereby minimizing infarct size and scar formation, and improving clinical outcomes by preventing adverse left ventricular remodeling and recurrent ischemic events. Many different cell types, including pluripotent stem cells and various adult-derived progenitor cells, have been shown to have therapeutic potential in preclinical studies, while early phase human trial experience has provided divergent outcomes and fundamental lessons, emphasizing that there remain key issues to address and challenges to overcome before cell therapy can be applied to wider clinical practice. The purpose of this review is to provide a balanced update on recent seminal developments in this exciting field and look to the next important steps to ensure its forward progression.

Characterization of a resident population of adventitial macrophage progenitor cells in postnatal vasculature.

RATIONALE: Macrophages regulate blood vessel structure and function in health and disease. The origins of tissue macrophages are diverse, with evidence for local production and circulatory renewal. OBJECTIVE: We identified a vascular adventitial population containing macrophage progenitor cells and investigated their origins and fate. METHODS AND RESULTS: Single-cell disaggregates from adult C57BL/6 mice were prepared from different tissues and tested for their capacity to form hematopoietic colony-forming units. Aorta showed a unique predilection for generating macrophage colony-forming units. Aortic macrophage colony-forming unit progenitors coexpressed stem cell antigen-1 and CD45 and were adventitially located, where they were the predominant source of proliferating cells in the aortic wall. Aortic Sca-1(+)CD45(+) cells were transcriptionally and phenotypically distinct from neighboring cells lacking stem cell antigen-1 or CD45 and contained a proliferative (Ki67(+)) Lin(-)c-Kit(+)CD135(-)CD115(+)CX3CR1(+)Ly6C(+)CD11b(-) subpopulation, consistent with the immunophenotypic profile of macrophage progenitors. Adoptive transfer studies revealed that Sca-1(+)CD45(+) adventitial macrophage progenitor cells were not replenished via the circulation from bone marrow or spleen, nor was their prevalence diminished by depletion of monocytes or macrophages by liposomal clodronate treatment or genetic deficiency of macrophage colony-stimulating factor. Rather adventitial macrophage progenitor cells were upregulated in hyperlipidemic ApoE(-/-) and LDL-R(-/-) mice, with adventitial transfer experiments demonstrating their durable contribution to macrophage progeny particularly in the adventitia, and to a lesser extent the atheroma, of atherosclerotic carotid arteries. CONCLUSIONS: The discovery and characterization of resident vascular adventitial macrophage progenitor cells provides new insight into adventitial biology and its participation in atherosclerosis and provokes consideration of the broader existence of local macrophage progenitors in other tissues.

Bone marrow mononuclear cell therapy for acute myocardial infarction: a perspective from the cardiovascular cell therapy research network.

To understand the role of bone marrow mononuclear cells in the treatment of acute myocardial infarction, this overview offers a retrospective examination of strengths and limitations of 3 contemporaneous trials with attention to critical design features and provides an analysis of the combined data set and implications for future directions in cell therapy for acute myocardial infarction.

Trends in cause of death after percutaneous coronary intervention.

BACKGROUND: The impact of changing demographics on causes of long-term death after percutaneous coronary intervention (PCI) remains incompletely defined. METHODS AND RESULTS: We evaluated trends in cause-specific long-term mortality after index PCI performed at a single center from 1991 to 2008. Deaths were ascertained by scheduled prospective surveillance. Cause was determined via telephone interviews, medical records, autopsy reports, and death certificates. Competing-risks analysis of cause-specific mortality was performed using 3 time periods of PCI (1991-1996, 1997-2002, and 2003-2008). Final follow-up was December 31, 2012. A total of 19 077 patients survived index PCI hospitalization, of whom 6988 subsequently died (37%, 4.48 per 100 person-years). Cause was determined in 6857 (98.1%). Across 3 time periods, there was a 33% decline in cardiac deaths at 5 years after PCI (incidence: 9.8%, 7.4%, and 6.6%) but a 57% increase in noncardiac deaths (7.1%, 8.5%, and 11.2%). Only 36.8% of deaths in the recent era were cardiac. Similar trends were observed regardless of age, extent of coronary disease, or PCI indication. After adjustment for baseline variables, there was a 50% temporal decline in cardiac mortality but no change in noncardiac mortality. The decline in cardiac mortality was driven by fewer deaths from myocardial infarction/sudden death (P<0.001) but not heart failure (P=0.85). The increase in noncardiac mortality was primarily attributable to cancer and chronic diseases (P<0.001). CONCLUSIONS: This study found a marked temporal switch from predominantly cardiac to predominantly noncardiac causes of death after PCI over 2 decades. The decline in cardiac mortality was independent of changes in baseline clinical characteristics. These findings have implications for patient care and clinical trial design.

Outcome of repair of myocardial bridging at the time of septal myectomy.

BACKGROUND: Myocardial bridging describes systolic compression of the muscular investment of a portion of an epicardial coronary artery. We evaluated the outcome of muscular bridge unroofing of the left anterior descending artery at the time of septal myectomy in patients with hypertrophic cardiomyopathy. METHODS: We conducted a case-controlled study of 36 patients (23 men; median age, 42 years) with hypertrophic cardiomyopathy and myocardial bridging. Group 1 patients had septal myectomy and concomitant unroofing (n = 13), group 2 patients underwent myectomy alone (n = 10), and group 3 patients were treated medically (n = 13). RESULTS: Angina was more prevalent preoperatively in group 1, 46% compared with 20% in group 2. Preoperative left ventricular outflow tract gradients of 67.8 ± 58.2 mm Hg and 74.1 ± 19.7 mm Hg were reduced to 1.9 ± 2.9 mm Hg in group 1 (p < 0.0001) and to 5.6 ± 8.8 mm Hg in group 2 (p < 0.0001). In the surgical groups, there were no early deaths or complications related to unroofing. Survival at 10 years was 83.3% in group 1 (p = 0.297), 100.0% in group 2, and 67.9% in group 3; there were no late sudden deaths. At follow-up, 77% in group 1 were asymptomatic compared with 70% of patients in group 2 (p = 0.19). There was no recurrent angina in group 1. CONCLUSIONS: Myocardial unroofing can be performed safely at the time of septal myectomy for left ventricular outflow tract obstruction. Angina was improved, but we found no difference in late survival compared with patients who had myocardial bridging and myectomy alone. Unroofing should be considered in patients with angina who have significant left anterior descending artery bridging and require myectomy.

Comparison between three-dimensional angiographic reconstruction and intravascular ultrasound: imaging of the left main coronary artery.

OBJECTIVES: The purpose of this study was to evaluate the left main (LM) coronary artery anatomy using three-dimensional (3D) quantitative coronary angiography (QCA) software as compared to intravascular ultrasound (IVUS). BACKGROUND: Percutaneous intervention of the LM coronary artery is becoming more common in selected patients with LM coronary artery disease (CAD). Quantification of LM CAD by conventional angiography can be difficult. IVUS is considered the gold standard to evaluate LM anatomy and severity of CAD but entails additional steps, catheters, and expertise. Our objective was to compare a novel quantitative angiographic analysis system with IVUS for LM anatomy. METHODS: Fifty five patients underwent both coronary angiography and IVUS of the LM. LM measurements were analyzed with 3D QCA (IC-PRO, Paieon, Israel) software using IVUS as the reference standard. The measurements included proximal, middle, distal minimal luminal diameter (MLD) and area. Additionally, lesion MLD, minimal luminal area were recorded by both systems. Bland-Altman plots were used to investigate agreement between the two imaging systems. RESULTS: Of the 55 patients in our cohort, average age was 66 ± 11 years (25% female). By Bland-Altman analysis there was very good agreement between 3D QCA and IVUS for measures of MLD and minimal lumen area (MLA). However, there was poor concordance in the estimation of plaque burden between the two methods. CONCLUSIONS: Our data demonstrate that 3D QCA software has fair agreement when compared with IVUS for imaging of LM MLD and MLA. These results suggest that 3D QCA could potentially be helpful to guide intervention of the LM.

Effect of the use and timing of bone marrow mononuclear cell delivery on left ventricular function after acute myocardial infarction: the TIME randomized trial.

CONTEXT: While the delivery of cell therapy after ST-segment elevation myocardial infarction (STEMI) has been evaluated in previous clinical trials, the influence of the timing of cell delivery on the effect on left ventricular function has not been analyzed. OBJECTIVES: To determine the effect of intracoronary autologous bone marrow mononuclear cell (BMC) delivery after STEMI on recovery of global and regional left ventricular function and whether timing of BMC delivery (3 days vs 7 days after reperfusion) influences this effect. DESIGN, SETTING, AND PATIENTS: A randomized, 2 × 2 factorial, double-blind, placebo-controlled trial, Timing In Myocardial infarction Evaluation (TIME) enrolled 120 patients with left ventricular dysfunction (left ventricular ejection fraction [LVEF] ≤ 45%) after successful primary percutaneous coronary intervention (PCI) of anterior STEMI between July 17, 2008, and November 15, 2011, as part of the Cardiovascular Cell Therapy Research Network sponsored by the National Heart, Lung, and Blood Institute. INTERVENTIONS: Intracoronary infusion of 150 × 106 BMCs or placebo (randomized 2:1) within 12 hours of aspiration and cell processing administered at day 3 or day 7 (randomized 1:1) after treatment with PCI. MAIN OUTCOME MEASURES: The primary end points were change in global (LVEF) and regional (wall motion) left ventricular function in infarct and border zones at 6 months measured by cardiac magnetic resonance imaging and change in left ventricular function as affected by timing of treatment on day 3 vs day 7. The secondary end points included major adverse cardiovascular events as well as changes in left ventricular volumes and infarct size. RESULTS: The mean (SD) patient age was 56.9 (10.9) years and 87.5% of participants were male. At 6 months, there was no significant increase in LVEF for the BMC group (45.2% [95% CI, 42.8% to 47.6%] to 48.3% [95% CI, 45.3% to 51.3%) vs the placebo group (44.5% [95% CI, 41.0% to 48.0%] to 47.8% [95% CI, 43.4% to 52.2%]) (P = .96). There was no significant treatment effect on regional left ventricular function observed in either infarct or border zones. There were no significant differences in change in global left ventricular function for patients treated at day 3 (−0.9% [95% CI, −6.6% to 4.9%], P = .76) or day 7 (1.1% [95% CI, −4.7% to 6.9%], P = .70). The timing of treatment had no significant effect on regional left ventricular function recovery. Major adverse events were rare among all treatment groups. CONCLUSION: Among patients with STEMI treated with primary PCI, the administration of intracoronary BMCs at either 3 days or 7 days after the event had no significant effect on recovery of global or regional left ventricular function compared with placebo. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00684021.