J. Dawn Abbott

Stromal Cell–Derived Factor-1α Plays a Critical Role in Stem Cell Recruitment to the Heart After Myocardial Infarction but Is Not Sufficient to Induce Homing in the Absence of Injury

Background—After myocardial infarction (MI), bone marrow–derived cells (BMDCs) are found within the myocardium. The mechanisms determining BMDC recruitment to the heart remain unclear. We investigated the role of stromal cell–derived factor-1α (SDF-1) in this process. Methods and Results—MI produced in mice by coronary ligation induced SDF-1 mRNA and protein expression in the infarct and border zone and decreased serum SDF-1 levels. By quantitative polymerase chain reaction, 48 hours after intravenous infusion of donor-lineage BMDCs, there were 80.5±15.6% more BDMCs in infarcted hearts compared with sham-operated controls (P<0.01). Administration of AMD3100, which specifically blocks binding of SDF-1 to its endogenous receptor CXCR4, diminished BMDC recruitment after MI by 64.2±5.5% (P<0.05), strongly suggesting a requirement for SDF-1 in BMDC recruitment to the infarcted heart. Forced expression of SDF-1 in the heart by adenoviral gene delivery 48 hours after MI doubled BMDC recruitment over MI alone (P<0.001) but did not enhance recruitment in the absence of MI, suggesting that SDF-1 can augment, but is not singularly sufficient for, BDMC recruitment to the heart. Gene expression analysis after MI revealed increased levels of several genes in addition to SDF-1, including those for vascular endothelial growth factor, matrix metalloproteinase-9, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1, which might act in concert with SDF-1 to recruit BMDCs to the injured heart. Conclusion—SDF-1/CXCR4 interactions play a crucial role in the recruitment of BMDCs to the heart after MI and can further increase homing in the presence, but not in the absence, of injury.

A comparison of bare-metal and drug-eluting stents for off-label indications.

BACKGROUND Recent reports suggest that off-label use of drug-eluting stents is associated with an increased incidence of adverse events. Whether the use of bare-metal stents would yield different results is unknown. METHODS We analyzed data from 6551 patients in the National Heart, Lung, and Blood Institute Dynamic Registry according to whether they were treated with drug-eluting stents or bare-metal stents and whether use was standard or off-label. Patients were followed for 1 year for the occurrence of cardiovascular events and death. Off-label use was defined as use in restenotic lesions, lesions in a bypass graft, left main coronary artery disease, or ostial, bifurcated, or totally occluded lesions, as well as use in patients with a reference-vessel diameter of less than 2.5 mm or greater than 3.75 mm or a lesion length of more than 30 mm. RESULTS Off-label use occurred in 54.7% of all patients with bare-metal stents and 48.7% of patients with drug-eluting stents. As compared with patients with bare-metal stents, patients with drug-eluting stents had a higher prevalence of diabetes, hypertension, renal disease, previous percutaneous coronary intervention and coronary-artery bypass grafting, and multivessel coronary artery disease. One year after intervention, however, there were no significant differences in the adjusted risk of death or myocardial infarction in patients with drug-eluting stents as compared with those with bare-metal stents, whereas the risk of repeat revascularization was significantly lower among patients with drug-eluting stents. CONCLUSIONS Among patients with off-label indications, the use of drug-eluting stents was not associated with an increased risk of death or myocardial infarction but was associated with a lower rate of repeat revascularization at 1 year, as compared with bare-metal stents. These findings support the use of drug-eluting stents for off-label indications.

Liberal versus restrictive transfusion thresholds for patients with symptomatic coronary artery disease.

BACKGROUND Prior trials suggest it is safe to defer transfusion at hemoglobin levels above 7 to 8 g/dL in most patients. Patients with acute coronary syndrome may benefit from higher hemoglobin levels. METHODS We performed a pilot trial in 110 patients with acute coronary syndrome or stable angina undergoing cardiac catheterization and a hemoglobin <10 g/dL. Patients in the liberal transfusion strategy received one or more units of blood to raise the hemoglobin level ≥10 g/dL. Patients in the restrictive transfusion strategy were permitted to receive blood for symptoms from anemia or for a hemoglobin <8 g/dL. The predefined primary outcome was the composite of death, myocardial infarction, or unscheduled revascularization 30 days post randomization. RESULTS Baseline characteristics were similar between groups except age (liberal, 67.3; restrictive, 74.3). The mean number of units transfused was 1.6 in the liberal group and 0.6 in the restrictive group. The primary outcome occurred in 6 patients (10.9%) in the liberal group and 14 (25.5%) in the restrictive group (risk difference = 15.0%; 95% confidence interval of difference 0.7% to 29.3%; P = .054 and adjusted for age P = .076). Death at 30 days was less frequent in liberal group (n = 1, 1.8%) compared to restrictive group (n = 7, 13.0%; P = .032). CONCLUSIONS The liberal transfusion strategy was associated with a trend for fewer major cardiac events and deaths than a more restrictive strategy. These results support the feasibility of and the need for a definitive trial.

Outcomes of 6906 Patients Undergoing Percutaneous Coronary Intervention in the Era of Drug-Eluting Stents Report of the DEScover Registry

Background— The DEScover Registry was designed to characterize patients selected for drug-eluting stents (DES) in routine clinical practice and their outcomes in the United States. Methods and Results— From January to June 2005, data were collected on 6906 patients who underwent percutaneous coronary intervention at 140 medical centers. Baseline characteristics and outcomes were compared on the basis of treatment with ≥1 bare-metal (BMS; n=397), sirolimus-eluting (SES; n=3873), or paclitaxel-eluting (PES; n=2636) stent. Clinical characteristics and the types of lesion treated for BMS patients differed substantially from those treated with DES, but minimal differences were noted between DES patients receiving SES or PES. At 1 year, the unadjusted cumulative incidence of death/myocardial infarction was higher in BMS than in DES patients (9.0% versus 5.2%; P=0.002) but similar in SES and PES patients (5.2% versus 5.3%; P=0.64). After adjustment, risk of death/MI was not significantly lower in DES- compared with BMS-treated patients (adjusted hazard ratio, 0.74; 95% confidence interval, 0.52 to 1.07). Although target vessel revascularization occurred less often in DES patients (9.5% versus 6.0%; P=0.007), rates were similar between SES and PES patients (6.3% versus 5.5%; P=0.20). Rates of stent thrombosis were similar among BMS (0.8%), SES (0.5%), and PES (0.8%) patients. Conclusions— In DEScover, differences in patient selection were observed between BMS and DES patients but not between SES and PES patients. DES use resulted in lower rates of clinically driven repeat revascularization with similar rates of stent thrombosis. These observations confirm the effectiveness and safety of both SES and PES in unselected patients.

Percutaneous Coronary Intervention Outcomes in Patients With Stable Obstructive Coronary Artery Disease and Myocardial Ischemia: A Collaborative Meta-analysis of Contemporary Randomized Clinical Trials

IMPORTANCE Myocardial ischemia in patients with stable coronary artery disease (CAD) has been repeatedly associated with impaired survival. However, it is unclear if revascularization with percutaneous coronary intervention (PCI) to relieve ischemia improves outcomes compared with medical therapy (MT). OBJECTIVE The objective of this study was to compare the effect of PCI and MT with MT alone exclusively in patients with stable CAD and objectively documented myocardial ischemia on clinical outcomes. DATA SOURCES MEDLINE, Cochrane, and PubMed databases from 1970 to November 2012. Unpublished data were obtained from investigators. STUDY SELECTION Randomized clinical trials of PCI and MT vs MT alone for stable coronary artery disease in which stents and statins were used in more than 50% of patients. DATA EXTRACTION For studies in which myocardial ischemia diagnosed by stress testing or fractional flow reserve was required for enrollment, descriptive and quantitative data were extracted from the published report. For studies in which myocardial ischemia was not a requirement for enrollment, authors provided data for only those patients with ischemia determined by stress testing prior to randomization. The outcomes analyzed included death from any cause, nonfatal myocardial infarction (MI), unplanned revascularization, and angina. Summary odds ratios (ORs) were obtained using a random-effects model. Heterogeneity was assessed using the Q statistic and I2. RESULTS In 5 trials enrolling 5286 patients, myocardial ischemia was diagnosed in 4064 patients by exercise stress testing, nuclear or echocardiographic stress imaging, or fractional flow reserve. Follow-up ranged from 231 days to 5 years (median, 5 years). The respective event rates for PCI with MT vs MT alone for death were 6.5% and 7.3% (OR, 0.90 [95% CI, 0.71-1.16); for nonfatal MI, 9.2% and 7.6% (OR, 1.24 [95% CI, 0.99-1.56]); for unplanned revascularization, 18.3% and 28.4% (OR, 0.64 [95% CI, 0.35-1.17); and for angina, 20.3% and 23.3% (OR, 0.91 [95% CI, 0.57-1.44]). CONCLUSIONS AND RELEVANCE In patients with stable CAD and objectively documented myocardial ischemia, PCI with MT was not associated with a reduction in death, nonfatal MI, unplanned revascularization, or angina compared with MT alone.

Factors related to the selection of surgical versus percutaneous revascularization in diabetic patients with multivessel coronary artery disease in the BARI 2D (Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes) trial.

OBJECTIVES We evaluated demographic, clinical, and angiographic factors influencing the selection of coronary artery bypass graft (CABG) surgery versus percutaneous coronary intervention (PCI) in diabetic patients with multivessel coronary artery disease (CAD) in the BARI 2D (Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes) trial. BACKGROUND Factors guiding selection of mode of revascularization for patients with diabetes mellitus and multivessel CAD are not clearly defined. METHODS In the BARI 2D trial, the selected revascularization strategy, CABG or PCI, was based on physician discretion, declared independent of randomization to either immediate or deferred revascularization if clinically warranted. We analyzed factors favoring selection of CABG versus PCI in 1,593 diabetic patients with multivessel CAD enrolled between 2001 and 2005. RESULTS Selection of CABG over PCI was declared in 44% of patients and was driven by angiographic factors including triple vessel disease (odds ratio [OR]: 4.43), left anterior descending stenosis >or=70% (OR: 2.86), proximal left anterior descending stenosis >or=50% (OR: 1.78), total occlusion (OR: 2.35), and multiple class C lesions (OR: 2.06) (all p < 0.005). Nonangiographic predictors of CABG included age >or=65 years (OR: 1.43, p = 0.011) and non-U.S. region (OR: 2.89, p = 0.017). Absence of prior PCI (OR: 0.45, p < 0.001) and the availability of drug-eluting stents conferred a lower probability of choosing CABG (OR: 0.60, p = 0.003). CONCLUSIONS The majority of diabetic patients with multivessel disease were selected for PCI rather than CABG. Preference for CABG over PCI was largely based on angiographic features related to the extent, location, and nature of CAD, as well as geographic, demographic, and clinical factors. (Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes [BARI 2D]; NCT00006305).

Impact of drug-eluting stents among insulin-treated diabetic patients: a report from the National Heart, Lung, and Blood Institute Dynamic Registry.

OBJECTIVES This study sought to evaluate the safety and efficacy of drug-eluting stents (DES) compared with bare-metal stents (BMS) in patients with insulin- and noninsulin-treated diabetes. BACKGROUND Diabetes is a powerful predictor of adverse events after percutaneous coronary interventions (PCI), and insulin-treated diabetic patients have worse outcomes. The DES are efficacious among patients with diabetes; however, their safety and efficacy, compared with BMS, among insulin-treated versus noninsulin-treated diabetic patients is not well established. METHODS Using the National Heart, Lung, and Blood Institute Dynamic Registry, we evaluated 1-year outcomes of insulin-treated (n = 817) and noninsulin-treated (n = 1,749) patients with diabetes who underwent PCI with DES versus BMS. RESULTS The use of DES, compared with BMS, was associated with a lower risk for repeat revascularization for both noninsulin-treated patients (adjusted hazard ratio [HR] = 0.59, 95% confidence interval [CI] 0.45 to 0.76) and insulin-treated subjects (adjusted HR = 0.63, 95% CI 0.44 to 0.90). With respect to safety in the overall diabetic population, DES use was associated with a reduction of death or myocardial infarction (adjusted HR = 0.75, 95% CI 0.58 to 0.96). However, this benefit was confined to the population of noninsulin-treated patients (adjusted HR = 0.57, 95% CI 0.41 to 0.81). Among insulin-treated patients, there was no difference in death or myocardial infarction risk between DES- and BMS-treated patients (adjusted HR = 0.95, 95% CI 0.65 to 1.39). CONCLUSIONS Drug-eluting stents are associated with lower risk for repeat revascularization compared with BMS in treating coronary artery disease among patients with either insulin- or noninsulin-treated diabetes. In addition, DES use is not associated with any significant increased safety risk compared with BMS. These findings suggest that DES should be the preferred strategy for diabetic patients.

Risk Factors for Incident Peripheral Arterial Disease in Type 2 Diabetes: Results From the Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes (BARI 2D) Trial

OBJECTIVE The aim of this article was to define risk factors for incidence of peripheral arterial disease (PAD) in a large cohort of patients with type 2 diabetes mellitus (T2DM), overall and within the context of differing glycemic control strategies. RESEARCH DESIGN AND METHODS The Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes (BARI 2D) randomized controlled trial assigned participants to insulin-sensitizing (IS) therapy versus insulin-providing (IP) therapy. A total of 1,479 participants with normal ankle-brachial index (ABI) at study entry were eligible for analysis. PAD outcomes included new ABI ≤0.9 with decrease at least 0.1 from baseline, lower extremity revascularization, or lower extremity amputation. Baseline risk factors within the overall cohort and time-varying risk factors within each assigned glycemic control arm were assessed using Cox proportional hazards models. RESULTS During an average 4.6 years of follow-up, 303 participants (20.5%) experienced an incident case of PAD. Age, sex, race, and baseline smoking status were all significantly associated with incident PAD in the BARI 2D cohort. Additional baseline risk factors included pulse pressure, HbA1c, and albumin-to-creatinine ratio (P < 0.05 for each). In stratified analyses of time-varying covariates, changes in BMI, LDL, HDL, systolic blood pressure, and pulse pressure were most predictive among IS patients, while change in HbA1c was most predictive among IP patients. CONCLUSIONS Among patients with T2DM, traditional cardiovascular risk factors were the main predictors of incident PAD cases. Stratified analyses showed different risk factors were predictive for patients treated with IS medications versus those treated with IP medications.

Randomized Trial of Bicarbonate or Saline Study for the Prevention of Contrast-Induced Nephropathy in Patients with CKD

BACKGROUND AND OBJECTIVES Sodium bicarbonate has been proposed for protection of the kidney from contrast-induced AKI (CIAKI). However, the effects of bicarbonate on long-term important clinical outcomes are uncertain. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS In a prospective, double-blind, multicenter randomized clinical trial, 391 patients with an eGFR<45 ml/min per 1.73 m(2) undergoing elective coronary or peripheral angiography were randomized to an infusion with a high dose of isotonic sodium bicarbonate (target 2.0 mEq/kg) or a similar molar amount of isotonic sodium chloride. The primary outcome was a composite of mortality, dialysis, or a sustained 20% reduction in eGFR at 6 months. RESULTS There were 391 patients enrolled between March 2010 and May 2012. The incidence of the primary outcome was 14.9% in the bicarbonate group and 16.3% in the control group in the intention-to-treat population (P=0.78). There was also no difference in the incidence of CIAKI between the treatment groups (14.5% versus 12.1%, respectively; P=0.20). CIAKI was associated with a higher incidence of sustained loss of kidney function at 6 months compared with those without CIAKI (21.2% versus 7.7%, respectively; P=0.06). CONCLUSIONS High-dose sodium bicarbonate infusion in patients with eGFR<45 ml/min per 1.73 m(2) undergoing angiography did not demonstrate a difference in incidence of the composite of death, dialysis, or sustained 6-month reduction in eGFR or CIAKI compared with sodium chloride.

Risk of death and myocardial infarction in patients with peripheral arterial disease undergoing percutaneous coronary intervention (from the National Heart, Lung and Blood Institute Dynamic Registry).

Patients with peripheral arterial disease (PAD) undergoing percutaneous coronary intervention (PCI) are at high risk for adverse cardiovascular events. Trends over time in outcomes with advances in PCI and medical therapy are unknown. We evaluated 866 patients with PAD in the National Heart, Lung, and Blood Institute (NHLBI) Dynamic Registry undergoing PCI according to treatment eras: the early bare metal stent (BMS) era (wave 1, 1997 to 1998, n = 180), the BMS era (waves 2 and 3, 1999 and 2001 to 2002, n = 339), and the drug-eluting stent (DES) era (waves 4 and 5, 2004 and 2006, n = 347). We compared in-hospital and 1-year outcomes by recruitment era. In-hospital coronary artery bypass graft surgery rates were significantly lower in the later eras (3.9%, 0.9%, and 0.6% for the early BMS, BMS, and DES eras, respectively, p for trend = 0.005), and an increasing percentage of patients were discharged on aspirin, β blockers, statins, and thienopyridines (p for trend <0.001 for all comparisons). Cumulative 1-year event rates in patients with PAD in the early BMS era, BMS era, and DES era for death were 13.7%, 10.5%, and 9.8% (p for trend = 0.21), those for myocardial infarction (MI) were 9.8%, 8.8%, and 10.0% (p for trend = 0.95), and those for repeat revascularization were 26.8%, 21.0%, and 17.2% (p for trend = 0.008). The 1-year adjusted hazard ratios of adverse events in patients with PAD using the early BMS era as the reference were 0.84 for death in the BMS era (95% confidence interval [CI] 0.46 to 1.55, p = 0.58) and 1.35 in the DES era (95% CI 0.71 to 2.56, p = 0.36), 0.89 for MI in the BMS era (95% CI 0.48 to 1.66, p = 0.72) and 1.02 in the DES era (95% CI 0.55 to 1.87, p = 0.95), and 0.63 for repeat revascularization in the BMS era (95% CI 0.41 to 0.97, p = 0.04) and 0.46 in the DES era (95% CI 0.29 to 0.73, p = 0.001). In conclusion, despite significant improvements in medical therapy and a decrease in repeat revascularization over time, patients with PAD who undergo PCI have a persistent high rate of death and MI.