Microvascular obstruction identifies a subgroup of patients who benefit from stem cell therapy following ST-elevation myocardial infarction.

BACKGROUND: Microvascular obstruction (MVO) is associated with greater infarct size, adverse left-ventricular (LV) remodeling and reduced ejection fraction following ST-elevation myocardial infarction (STEMI). We hypothesized that patients with MVO may constitute a subgroup of patients that would benefit from intracoronary stem cell delivery with bone marrow mononuclear cells (BMCs) given previous findings that BMCs tended to improve LV function only in patients with significant LV dysfunction. METHODS AND RESULTS: We analyzed the cardiac MRIs of 356 patients (303 M, 53 F) with anterior STEMIs who received autologous BMCs or placebo / control as part of 4 randomized clinical trials that included the Cardiovascular Cell Therapy Research Network (CCTRN) TIME trial and its pilot, the multicenter French BONAMI trial and SWISS-AMI trials. A total of 327 patients had paired imaging data at 1 year. All patients received 100 to 150 million intracoronary autologous BMCs or placebo / control 3 to 7 days following primary PCI and stenting. LV function, volumes, infarct size and MVO were assessed prior to infusion of BMCs and 1 year later. Patients with MVO (n = 210) had reduced LVEF and much greater infarct size and LV volumes compared to patients without MVO (n = 146) (P < .01). At 12 months, patients with MVO who received BMCs had significantly greater recovery of LVEF compared to those patients with MVO who received placebo (absolute difference = 2.7%; P < .05). Similarly, left-ventricular end-diastolic (LVEDVI) and end-systolic volume indices (LVESVI) demonstrated significantly less adverse remodeling in patients with MVO who received BMCs compared to placebo. In contrast, no improvement in LVEF or LV volumes was observed in those patients without MVO who received BMCs compared to placebo. CONCLUSIONS: The presence of MVO on cardiac MRI following STEMI identifies a subgroup of patients who benefit from intracoronary stem cell therapy.

Frequency and outcomes of STEMI patients presenting between 12 and 24 h after symptom onset: Late-presenting STEMI.

OBJECTIVES: To assess the characteristics and prognosis of ST-elevation myocardial infarction (STEMI) patients, presenting between 12 and 24 h after symptom onset, in contemporary regional STEMI systems of care in the United States. BACKGROUND: Previous observational studies have been inconsistent regarding the benefit of primary percutaneous coronary intervention (PCI) compared with conservative management for late-presenting STEMI patients and the majority of randomized trials are from the fibrinolytic era. METHODS: Using a two-center registry-based cohort from March 2003 to December 2020, we evaluated the frequency, clinical characteristics, and outcomes of STEMI patients, stratified by symptom onset to balloon time: <3, 3-6, 6-12, and 12-24 h (late presenters). RESULTS: Among 5427 STEMI patients with available symptom onset time, 6.2% were late presenters, which increased to 11% during the early phase of the Covid-19 pandemic. As symptom onset to balloon time increased, patients were more likely to be older, female, and have a history of hypertension and diabetes mellitus. Late presenters with an identifiable culprit lesion were less likely to be revascularized with PCI (96%, 96%, 95%, and 92%; p for trend = 0.004) and had a longer median door-to-balloon time (82, 109, 107, and 117 min; p for trend < 0.001). In-hospital and 1-year death risks were comparable between late and earlier presenters. CONCLUSION: Despite the unfavorable risk profile and longer door-to-balloon time, clinical outcomes of late presenters were similar to those presenting within 12 h of symptom onset.

Increasing myocardial edema is associated with greater microvascular obstruction in ST-segment elevation myocardial infarction.

Microvascular obstruction (MVO) frequently develops after ST-elevation myocardial infarction (STEMI) and is associated with increased mortality and adverse left ventricular remodeling. We hypothesized that increased extravascular compressive forces in the myocardium that arise from the development of myocardial edema because of ischemia-reperfusion injury would contribute to the development of MVO. We measured MVO, infarct size, and left ventricular mass in patients with STEMI (n = 385) using cardiac MRI 2 to 3 days following successful percutaneous coronary intervention and stenting. MVO was found in 57% of patients with STEMI. The average infarct size was 45 ± 29 g. Patients with MVO had significantly greater infarct size and reduced left ventricular (LV) function (P < 0.01) compared with patients without MVO. Patients with MVO had significantly greater LV mass than patients without MVO and there was a linear increase in MVO with increasing LV mass (P < 0.001). Myocardial edema by T2-weighted imaging increased with increasing LV mass and patients with MVO had significantly greater myocardial edema than patients without MVO (P < 0.01). Patients with MVO had significantly greater left ventricular end-diastolic pressure (LVEDP) than patients without MVO (P < 0.05). In a cohort of patients with STEMI who underwent primary percutaneous intervention, we observed that MVO increased linearly with increasing LV mass and was associated with increased myocardial edema and higher LVEDP. These observations support the concept that extravascular compressive forces in the left ventricle may increase with increasing ischemic injury and contribute to the development of MVO.NEW & NOTEWORTHY Patients with STEMI (n = 385) had cardiac MRIs 2 to 3 days following reperfusion with primary PCI to determine the relationship between myocardial edema, LV mass, and MVO. We observed that MVO increased linearly with LV mass and that myocardial edema measured by T2-imaging also increased linearly with LV mass. Patients with MVO had greater edema and LVEDP than subjects without MVO. These findings suggest that myocardial edema which arises from ischemia-reperfusion injury may result in extravascular compression of the microcirculation manifested as MVO on cardiac MRI.

Challenges and outcomes of the double kissing crush stenting technique: Insights from the PROGRESS-BIFURCATION registry.

BACKGROUND: Although the double kissing (DK) crush stenting technique can provide excellent outcomes in percutaneous coronary intervention (PCI) of bifurcation lesions, it can be challenging to perform. METHODS: We examined the clinical and angiographic characteristics, challenges encountered, and procedural outcomes of bifurcation PCI with DK crush in Prospective Global Registry of Percutaneous Coronary Intervention in Bifurcation Lesions (PROGRESS-BIFURCATION, NCT05100992). RESULTS: DK crush was used in 48 of 435 bifurcation lesions (11%). Technical success was 100%, procedural success was 96%, and the incidence of in-hospital major adverse cardiovascular events was 4%. Challenges while performing DK crush were encountered in 26 lesions (54%): (1) difficulty in side branch (SB) first rewiring (38%) that was overcome with the use of a new guidewire (30%) or a microcatheter (15%); (2) inability to deliver balloon to an SB for the first kiss (54%) that was overcome with the use of a smaller balloon (86%), rewiring (29%), microcatheter (14%), and increased support 7%; (3) difficulty in SB second rewiring (19%) that was overcome with the use of a new guidewire (80%) and/or microcatheter (60%). DK crush was more often performed in left main and proximal left anterior descending artery lesions (70% vs. 50%, p = 0.014). DK crush cases required more contrast (198 ± 84 ml vs. 163 ± 70 ml, p = 0.003), fluoroscopy time (35 ± 20 min vs. 25 ± 21 min, p = 0.004), and lasted longer (137 ± 69 min vs. 99 ± 66 min, p = 0.001) compared with non-DK crush techniques. CONCLUSIONS: While challenges are common when performing DK crush bifurcation stenting, success rates are high and complication rates are low.

Outcomes and challenges of the provisional stenting technique: Insights from the PROGRESS-BIFURCATION registry.

BACKGROUND: Provisional stenting is the most commonly used coronary bifurcation stenting strategy. METHODS: We examined the clinical and angiographic characteristics, challenges encountered, and procedural outcomes with the provisional bifurcation stenting strategy in the Prospective Global Registry of Percutaneous Coronary Intervention (PCI) in Bifurcation Lesions (PROGRESS-BIFURCATION, NCT05100992). RESULTS: Provisional stenting was used in 334 of 430 bifurcation interventions (78%). Technical success was lower (95% vs. 100%, p = 0.017) in provisional, but procedural success (90% vs. 95%, p = 0.095) and incidence of in-hospital major adverse cardiovascular events were similar (5% vs. 5%, p = 0.945) compared with two-stent strategies. Provisional was less often preferred in left main/left anterior descending involvement (47% vs. 73%, p < 0.001). Provisional stenting cases had smaller side branch (SB) diameter (2.4 ± 0.5 vs. 2.7 ± 0.6 mm, p < 0.001), shorter SB lesion length (5 [3-8] vs. 10 [5-10] mm, p < 0.001), less SB diameter stenosis (46 ± 35 vs. 81 ± 20%, p < 0.001), and were less likely to be Medina 1,1,1 (34% vs. 73%, p < 0.001). PCI challenges were less common (30% vs. 58%, p < 0.001) with provisional stenting: (1) rewiring difficulty (43%) that was overcome with use of a different wire (74%) or microcatheter (46%); (2) inability to deliver a stent (22%) or balloon (9%) that was overcome with use of a smaller balloon (88%), rewiring (25%), or increased support/microcatheter (25%). CONCLUSIONS: Provisional bifurcation stenting was more often performed in distal lesions with less SB involvement and had lower technical success, but similar procedural success and complications compared with two-stent strategies.

Epicardial delivery of XC001 gene therapy for refractory angina coronary treatment (The EXACT Trial): Rationale, design, and clinical considerations.

BACKGROUND: Patients with refractory angina (RA) have poor quality of life and new therapies are needed. XC001 is a novel adenoviral vector expressing multiple isoforms of vascular endothelial growth factor (VEGF) promoting an enhanced local angiogenic effect. METHODS: The Epicardial Delivery of XC001 Gene Therapy for Refractory Angina Coronary Treatment (EXACT) trial is a 6-month (with 6-month extension) phase 1/2, first-in-human, multicenter, open-label, single-arm, dose-escalation study to evaluate the safety, tolerability, and preliminary efficacy of XC001 in patients with RA. The trial will enroll 33 patients in an initial (n = 12) ascending dose-escalation phase (1 × 109, 1 × 1010, 4 × 1010, and 1 × 1011 viral particles), followed by phase 2 (n = 21) assessing the highest tolerated dose. Patients must have stable Canadian Cardiovascular Society (CCS) class II-IV angina on maximally tolerated medical therapy without options for conventional revascularization, demonstrable ischemia on stress testing, and angina limiting exercise tolerance. XC001 will be delivered directly to ischemic myocardium via surgical transthoracic epicardial access. The primary outcome is safety via adverse event monitoring through 6 months. Efficacy assessments include difference from baseline to month 6 in time to 1 mm of ST segment depression, time to angina, and total exercise duration; myocardial blood flow at rest, and stress and coronary flow reserve by positron emission tomography; quality of life; CCS functional class; and angina frequency. CONCLUSIONS: The EXACT trial will determine whether direct intramyocardial administration of XC001 in patients with RA is safe and evaluate its effect on exercise tolerance, myocardial perfusion, angina and physical activity, informing future clinical investigation. CLINICAL TRIAL REGISTRATION: NCT04125732.

Outcomes of intravascular brachytherapy for recurrent drug-eluting in-stent restenosis.

OBJECTIVES: To examine the outcomes of vascular brachytherapy (VBT) for recurrent drug-eluting stents (DES) in-stent restenosis (ISR). BACKGROUND: Recurrent DES-ISR can be challenging to treat. VBT has been used with encouraging results. METHODS: We report the long-term outcomes of patients with recurrent DES-ISR treated with VBT between January 2014 and September 2018 at a tertiary care institution. The main outcome was target lesion failure (TLF), defined as the composite of clinically driven target lesion revascularization (TLR), target lesion myocardial infarction (MI), and target lesion-related cardiac death. Cox proportional hazards analysis was performed to identify variables associated with recurrent TLF. RESULTS: During the study period, 116 patients (143 lesions) underwent VBT. Median follow-up was 24.7 (14.5-35.4) months. The incidence of TLR, target-lesion MI, and TLF was 18.9%, 5.6%,and 20.1% at 1 year, and 29.4%, 10.5%, and 32.9% at 2 years.Initial presentation with acute coronary syndrome (ACS) was independently associated with TLF (hazard ratio = 1.975, 95% CI [1.120, 3.485], p = .019). Lesions treated with intravascular ultrasound (IVUS) guidance had a lower incidence of TLR (14.3% vs. 39.6%, log-rank p = .038), and a trend toward lower incidence of TLF (19% vs. 42.6%, log-rank p = .086). CONCLUSIONS: VBT can improve the treatment of recurrent DES-ISR, but TLF occurs in approximately one in three patients at 2 years. Initial presentation with ACS was associated with higher TLF and the use of IVUS with a trend for lower incidence of TLF.

Temporal changes in patient characteristics and outcomes in ST-segment elevation myocardial infarction 2003-2018.

BACKGROUND: We sought to describe changes in demographic variables, process of care measures, and outcomes of patients treated in a regional ST-segment elevation myocardial infarction (STEMI) program over the last 15 years. METHODS: We describe demographic variables, process of care measures, and outcomes of patients treated in the program in various 5-year time periods: 2003-2007 (n = 1,821), 2008-2012 (n = 1,968), and 2013-2018 (n = 2,223). The primary outcome measures were in-hospital and 30-day mortality. RESULTS: Among 6,012 STEMI patients treated from 2003 to 2018 we observed a significant increase in mean age at presentation (62 ± 14 to 64 ± 13 years) and diabetes (14-22%, p < .01). The proportion of patients with cardiogenic shock (CS) and cardiac arrest (CA) pre-PCI increased significantly from 9.5% to 11.1% and 8.5% to 12.7% (p < .05), respectively. The median door-to-balloon (D2B) times decreased from 98 to 93 min and total ischemic time decreased from 202 to 185 min (all p < .05). Despite increased patient complexity, the proportion of nontransfer and transfer patients achieving D2B times consistent with guideline recommendations remained unchanged (for nontransfer patients 79-82%, p = .45 and for transfer patients 65-64%, p = .34). Among all STEMI patients, in-hospital mortality increased during the study period from 4.9 to 6.9% (p = .007) but remained stable (<2%) when CA and CS patients were excluded. CONCLUSIONS: Over the last 15 years, short-term STEMI mortality has increased despite improvements in care delivery metrics. Patients with CA and/or CS now represent 10% of STEMI patients and are responsible for 80% of deaths. Therefore, efforts to improve STEMI mortality, and metrics for assessing STEMI programs, should focus on these patients.

NHLBI-Sponsored Randomized Trial of Postconditioning During Primary Percutaneous Coronary Intervention for ST-Elevation Myocardial Infarction.

RATIONALE: Postconditioning at the time of primary percutaneous coronary intervention (PCI) for ST-segment-elevation myocardial infarction may reduce infarct size and improve myocardial salvage. However, clinical trials have shown inconsistent benefit. OBJECTIVE: We performed the first National Heart, Lung, and Blood Institute-sponsored trial of postconditioning in the United States using strict enrollment criteria to optimize the early benefits of postconditioning and assess its long-term effects on left ventricular (LV) function. METHODS AND RESULTS: We randomized 122 ST-segment-elevation myocardial infarction patients to postconditioning (4, 30 seconds PTCA [percutaneous transluminal coronary angioplasty] inflations/deflations)+PCI (n=65) versus routine PCI (n=57). All subjects had an occluded major epicardial artery (thrombolysis in myocardial infarction=0) with ischemic times between 1 and 6 hours with no evidence of preinfarction angina or collateral blood flow. Cardiac magnetic resonance imaging measured at 2 days post-PCI showed no difference between the postconditioning group and control in regards to infarct size (22.5±14.5 versus 24.0±18.5 g), myocardial salvage index (30.3±15.6% versus 31.5±23.6%), or mean LV ejection fraction. Magnetic resonance imaging at 12 months showed a significant recovery of LV ejection fraction in both groups (61.0±11.4% and 61.4±9.1%; P<0.01). Subjects randomized to postconditioning experienced more favorable remodeling over 1 year (LV end-diastolic volume =157±34 to 150±38 mL) compared with the control group (157±40 to 165±45 mL; P<0.03) and reduced microvascular obstruction ( P=0.05) on baseline magnetic resonance imaging and significantly less adverse LV remodeling compared with control subjects with microvascular obstruction ( P<0.05). No significant adverse events were associated with the postconditioning protocol and all patients but one (hemorrhagic stroke) survived through 1 year of follow-up. CONCLUSIONS: We found no early benefit of postconditioning on infarct size, myocardial salvage index, and LV function compared with routine PCI. However, postconditioning was associated with improved LV remodeling at 1 year of follow-up, especially in subjects with microvascular obstruction. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov . Unique identifier: NCT01324453.

Intracoronary ALLogeneic heart STem cells to Achieve myocardial Regeneration (ALLSTAR): a randomized, placebo-controlled, double-blinded trial.

AIMS: Cardiosphere-derived cells (CDCs) are cardiac progenitor cells that exhibit disease-modifying bioactivity in various models of cardiomyopathy and in previous clinical studies of acute myocardial infarction (MI), dilated cardiomyopathy, and Duchenne muscular dystrophy. The aim of the study was to assess the safety and efficacy of intracoronary administration of allogeneic CDCs in the multicentre, randomized, double-blinded, placebo-controlled, intracoronary ALLogeneic heart STem cells to Achieve myocardial Regeneration (ALLSTAR) trial. METHODS AND RESULTS: We enrolled patients 4 weeks to 12 months after MI, with left ventricular ejection fraction (LVEF) ≤45% and LV scar size ≥15% of LV mass by magnetic resonance imaging (MRI). A pre-specified interim analysis was performed when 6-month MRI data were available. The trial was subsequently stopped due to the low probability of detecting a significant treatment effect of CDCs based on the primary endpoint. Patients were randomly allocated in a 2:1 ratio to receive CDCs or placebo in the infarct-related artery by stop-flow technique. The primary safety endpoint was the occurrence, during 1-month post-intracoronary infusion, of acute myocarditis attributable to allogeneic CDCs, ventricular tachycardia- or ventricular fibrillation-related death, sudden unexpected death, or a major adverse cardiac event (death or hospitalization for heart failure or non-fatal MI or need for left ventricular assist device or heart transplant). The primary efficacy endpoint was the relative percentage change in infarct size at 12 months post-infusion as assessed by contrast-enhanced cardiac MRI. We randomly allocated 142 eligible patients of whom 134 were treated (90 to the CDC group and 44 to the placebo group). The mean baseline LVEF was 40% and the mean scar size was 22% of LV mass. No primary safety endpoint events occurred. There was no difference in the percentage change from baseline in scar size (P = 0.51) between CDCs and placebo groups at 6 months. Compared with placebo, there were significant reductions in LV end-diastolic volume (P = 0.02), LV end-systolic volume (P = 0.02), and N-terminal pro b-type natriuretic peptide (NT-proBNP) (P = 0.02) at 6 months in CDC-treated patients. CONCLUSION: Intracoronary infusion of allogeneic CDCs in patients with post-MI LV dysfunction was safe but did not reduce scar size relative to placebo at 6 months. Nevertheless, the reductions in LV volumes and NT-proBNP reveal disease-modifying bioactivity of CDCs. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT01458405.

Meta-analysis of short- and long-term efficacy of mononuclear cell transplantation in patients with myocardial infarction.

BACKGROUND: Mononuclear cells (MNCs) have been tested in clinical trials across multiple cardiovascular pathologies with mixed results. Major adverse cardiac events (MACE) and markers of cardiovascular capacity have been particularly challenging to interpret because of small size. This meta-analysis is aimed to assess the efficacy of MNC therapy in randomized clinical trials to identify the markers of efficiency that could influence future trial design. METHODS: PubMed, Embase, Cochrane library, and ClinicalTrials.gov were searched from inception through November 8, 2018. Changes in left ventricular ejection fraction (LVEF) and infarct size from baseline to follow-up were selected as primary outcomes. Changes in the left ventricular end-systolic volume, left ventricular end-diastolic volume, brain natriuretic peptide/N-terminal pro-B-type natriuretic peptide, 6-minute walk test, New York Heart Association class, and MACE incidences were considered secondary outcomes. RESULTS: In short-term follow-up, patients treated with MNCs demonstrated a significant increase in absolute LVEF of 2.21% (95% CI 1.59-2.83; P < .001; I2 = 32%) and 6.01% (95% CI 4.45-7.57; P < .001; I2 = 0%) in acute myocardial infarction (AMI) and ischemic cardiomyopathy studies, respectively. This effect was sustained in long-term follow-up. MNC therapy significantly reduced left ventricular end-systolic volume; however, infarct size, 6-minute walk test, New York Heart Association class, and MACE rates were comparable. CONCLUSIONS: MNC therapy may convey a modest but sustained increase in LVEF in ischemic cardiomyopathy patients, supporting further investigation. AMI trials, however, demonstrated minimal improvement in LVEF of unclear clinical significance, suggesting a limited role for MNC therapy in AMI.

TIME Trial: Effect of Timing of Stem Cell Delivery Following ST-Elevation Myocardial Infarction on the Recovery of Global and Regional Left Ventricular Function: Final 2-Year Analysis.

RATIONALE: The TIME trial (Timing in Myocardial Infarction Evaluation) was the first cell therapy trial sufficiently powered to determine if timing of cell delivery after ST-segment-elevation myocardial infarction affects recovery of left ventricular (LV) function. OBJECTIVE: To report the 2-year clinical and cardiac magnetic resonance imaging results and their modification by microvascular obstruction. METHODS AND RESULTS: TIME was a randomized, double-blind, placebo-controlled trial comparing 150 million bone marrow mononuclear cells versus placebo in 120 patients with anterior ST-segment-elevation myocardial infarctions resulting in LV dysfunction. Primary end points included changes in global (LV ejection fraction) and regional (infarct and border zone) function. Secondary end points included changes in LV volumes, infarct size, and major adverse cardiac events. Here, we analyzed the continued trajectory of these measures out to 2 years and the influence of microvascular obstruction present at baseline on these long-term outcomes. At 2 years (n=85), LV ejection fraction was similar in the bone marrow mononuclear cells (48.7%) and placebo groups (51.6%) with no difference in regional LV function. Infarct size and LV mass decreased ≥30% in each group at 6 months and declined gradually to 2 years. LV volumes increased ≈10% at 6 months and remained stable to 2 years. Microvascular obstruction was present in 48 patients at baseline and was associated with significantly larger infarct size (56.5 versus 36.2 g), greater adverse LV remodeling, and marked reduction in LV ejection fraction recovery (0.2% versus 6.2%). CONCLUSIONS: In one of the longest serial cardiac magnetic resonance imaging analyses of patients with large anterior ST-segment-elevation myocardial infarctions, bone marrow mononuclear cells administration did not improve recovery of LV function over 2 years. Microvascular obstruction was associated with reduced recovery of LV function, greater adverse LV remodeling, and more device implantations. The use of cardiac magnetic resonance imaging leads to greater dropout of patients over time because of device implantation in patients with more severe LV dysfunction resulting in overestimation of clinical stability of the cohort. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00684021.

Rationale and Design of the CONCERT-HF Trial (Combination of Mesenchymal and c-kit+ Cardiac Stem Cells As Regenerative Therapy for Heart Failure).

RATIONALE: Autologous bone marrow mesenchymal stem cells (MSCs) and c-kit+ cardiac progenitor cells (CPCs) are 2 promising cell types being evaluated for patients with heart failure (HF) secondary to ischemic cardiomyopathy. No information is available in humans about the relative efficacy of MSCs and CPCs and whether their combination is more efficacious than either cell type alone. OBJECTIVE: CONCERT-HF (Combination of Mesenchymal and c-kit+ Cardiac Stem Cells As Regenerative Therapy for Heart Failure) is a phase II trial aimed at elucidating these issues by assessing the feasibility, safety, and efficacy of transendocardial administration of autologous MSCs and CPCs, alone and in combination, in patients with HF caused by chronic ischemic cardiomyopathy (coronary artery disease and old myocardial infarction). METHODS AND RESULTS: Using a randomized, double-blinded, placebo-controlled, multicenter, multitreatment, and adaptive design, CONCERT-HF examines whether administration of MSCs alone, CPCs alone, or MSCs+CPCs in this population alleviates left ventricular remodeling and dysfunction, reduces scar size, improves quality of life, or augments functional capacity. The 4-arm design enables comparisons of MSCs alone with CPCs alone and with their combination. CONCERT-HF consists of 162 patients, 18 in a safety lead-in phase (stage 1) and 144 in the main trial (stage 2). Stage 1 is complete, and stage 2 is currently randomizing patients from 7 centers across the United States. CONCLUSIONS: CONCERT-HF will provide important insights into the potential therapeutic utility of MSCs and CPCs, given alone and in combination, for patients with HF secondary to ischemic cardiomyopathy. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02501811.

Incidence, predictors, management and outcomes of coronary perforations.

OBJECTIVES: We examined the contemporary incidence, types, predictors, angiographic characteristics, management and outcomes of coronary perforation. BACKGROUND: Coronary perforation is a rare, but important, complication of percutaneous coronary intervention (PCI). There is lack of data on perforations stratified as large and distal vessel perforations. METHODS: Retrospective, observational cohort study of all patients who underwent PCI at a high volume, tertiary hospital between the years 2009 and 2016. Angiograms of all coronary perforation cases were reviewed to determine the mechanism, type, and management of perforation. Risk-adjusted periprocedural complication rates were compared between patients with and without coronary perforation. One-year mortality outcomes of patients with large vessel vs. distal vessel perforation were also examined. RESULTS: Coronary perforation occurred in 68 of 13,339 PCIs (0.51%) performed during the study period: 51 (75%) were large vessel perforations and 17 (25%) distal vessel perforations. Most (67%) large vessel perforations were due to balloon/stent inflation, whereas most (94%) distal vessel perforations were due to guidewire exit. Patients with coronary perforations had significantly higher risk for periprocedural complications (adjusted odds ratio 7.57; 95% CI: 4.22-13.50; P < 0.001). Only one patient with large vessel perforation required emergency cardiac surgery, yet in-hospital mortality was high with both large vessel (7.8%) and distal vessel (11.8%) perforations. CONCLUSIONS: Coronary perforation is an infrequent, but potentially severe PCI complication. Most coronary perforations are large vessel perforations. Although coronary perforations rarely lead to emergency cardiac surgery, both distal vessel and large vessel perforations are associated with high in-hospital mortality, highlighting the importance of prevention.

Peripheral Blood Cytokine Levels After Acute Myocardial Infarction: IL-1ß- and IL-6-Related Impairment of Bone Marrow Function.

RATIONALE: Intracoronary infusion of bone marrow (BM) mononuclear cells after acute myocardial infarction (AMI) has led to limited improvement in left ventricular function. Although experimental AMI models have implicated cytokine-related impairment of progenitor cell function, this response has not been investigated in humans. OBJECTIVE: To test the hypothesis that peripheral blood (PB) cytokines predict BM endothelial progenitor cell colony outgrowth and cardiac function after AMI. METHODS AND RESULTS: BM and PB samples were collected from 87 participants 14 to 21 days after AMI and BM from healthy donors was used as a reference. Correlations between cytokine concentrations and cell phenotypes, cell functions, and post-AMI cardiac function were determined. PB interleukin-6 (IL-6) negatively correlated with endothelial colony-forming cell colony maximum in the BM of patients with AMI (estimate±SE, -0.13±0.05; P=0.007). BM from healthy individuals showed a dose-dependent decrease in endothelial colony-forming cell colony outgrowth in the presence of exogenous IL-1ß or IL-6 (P<0.05). Blocking the IL-1R or IL-6R reversed cytokine impairment. In AMI study participants, the angiogenic cytokine platelet-derived growth factor BB glycoprotein correlated positively with BM-derived colony-forming unit-endothelial colony maximum (estimate±SE, 0.01±0.002; P<0.001), multipotent mesenchymal stromal cell colony maximum (estimate±SE, 0.01±0.002; P=0.002) in BM, and mesenchymal stromal cell colony maximum in PB (estimate±SE, 0.02±0.005; P<0.001). CONCLUSIONS: Two weeks after AMI, increased PB platelet-derived growth factor BB glycoprotein was associated with increased BM function, whereas increased IL-6 was associated with BM impairment. Validation studies confirmed inflammatory cytokine impairment of BM that could be reversed by blocking IL-1R or IL-6R. Together, these studies suggest that blocking IL-1 or IL-6 receptors may improve the regenerative capacity of BM cells after AMI. CLINICAL TRIAL REGISTRATIONS: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00684060.

Autologous CD34+ cell therapy improves exercise capacity, angina frequency and reduces mortality in no-option refractory angina: a patient-level pooled analysis of randomized double-blinded trials.

Aims: Autologous CD34+ (auto-CD34+) cells represent an attractive option for the treatment of refractory angina. Three double-blinded randomized trials (n = 304) compared intramyocardial (IM) auto-CD34+ cells with IM placebo injections to affect total exercise time (TET), angina frequency (AF), and major adverse cardiac events (MACE). Patient-level data were pooled from the Phase I, Phase II ACT-34, ACT-34 extension, and Phase III RENEW trials to determine the efficacy and safety of auto-CD34+ cells. Methods and results: Treatment effects for TET were analysed using an analysis of covariance mixed-effects model and for AF using Poisson regression in a log linear model with repeated measures. The Kaplan-Meier rate estimates for MACE were compared using the log-rank test. Autologous CD34+ cell therapy improved TET by 46.6 s [3 months, 95% confidence interval (CI) 13.0 s-80.3 s; P = 0.007], 49.5 s (6 months, 95% CI 9.3-89.7; P = 0.016), and 44.7 s (12 months, 95% CI - 2.7 s-92.1 s; P = 0.065). The relative frequency of angina was 0.78 (95% CI 0.63-0.98; P = 0.032), 0.66 (0.48-0.91; P = 0.012), and 0.58 (0.38-0.88; P = 0.011) at 3-, 6- and 12-months in auto-CD34+ compared with placebo patients. Results remained concordant when analysed by treatment received and when confined to the Phase III dose of 1 × 105 cells/kg. Autologous CD34 + cell therapy significantly decreased mortality (12.1% vs. 2.5%; P = 0.0025) and numerically reduced MACE (38.9% vs. 30.0; P = 0.14) at 24 months. Conclusion: Treatment with auto-CD34+ cells resulted in clinically meaningful durable improvements in TET and AF at 3-, 6- and 12-months, as well as a reduction in 24-month mortality in this patient-level meta-analysis.

Evaluation of Cell Therapy on Exercise Performance and Limb Perfusion in Peripheral Artery Disease: The CCTRN PACE Trial (Patients With Intermittent Claudication Injected With ALDH Bright Cells).

BACKGROUND: Atherosclerotic peripheral artery disease affects 8% to 12% of Americans >65 years of age and is associated with a major decline in functional status, increased myocardial infarction and stroke rates, and increased risk of ischemic amputation. Current treatment strategies for claudication have limitations. PACE (Patients With Intermittent Claudication Injected With ALDH Bright Cells) is a National Heart, Lung, and Blood Institute-sponsored, randomized, double-blind, placebo-controlled, phase 2 exploratory clinical trial designed to assess the safety and efficacy of autologous bone marrow-derived aldehyde dehydrogenase bright (ALDHbr) cells in patients with peripheral artery disease and to explore associated claudication physiological mechanisms. METHODS: All participants, randomized 1:1 to receive ALDHbr cells or placebo, underwent bone marrow aspiration and isolation of ALDHbr cells, followed by 10 injections into the thigh and calf of the index leg. The coprimary end points were change from baseline to 6 months in peak walking time (PWT), collateral count, peak hyperemic popliteal flow, and capillary perfusion measured by magnetic resonance imaging, as well as safety. RESULTS: A total of 82 patients with claudication and infrainguinal peripheral artery disease were randomized at 9 sites, of whom 78 had analyzable data (57 male, 21 female patients; mean age, 66±9 years). The mean±SEM differences in the change over 6 months between study groups for PWT (0.9±0.8 minutes; 95% confidence interval [CI] -0.6 to 2.5; P=0.238), collateral count (0.9±0.6 arteries; 95% CI, -0.2 to 2.1; P=0.116), peak hyperemic popliteal flow (0.0±0.4 mL/s; 95% CI, -0.8 to 0.8; P=0.978), and capillary perfusion (-0.2±0.6%; 95% CI, -1.3 to 0.9; P=0.752) were not significant. In addition, there were no significant differences for the secondary end points, including quality-of-life measures. There were no adverse safety outcomes. Correlative relationships between magnetic resonance imaging measures and PWT were not significant. A post hoc exploratory analysis suggested that ALDHbr cell administration might be associated with an increase in the number of collateral arteries (1.5±0.7; 95% CI, 0.1-2.9; P=0.047) in participants with completely occluded femoral arteries. CONCLUSIONS: ALDHbr cell administration did not improve PWT or magnetic resonance outcomes, and the changes in PWT were not associated with the anatomic or physiological magnetic resonance imaging end points. Future peripheral artery disease cell therapy investigational trial design may be informed by new anatomic and perfusion insights. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01774097.

The CardiAMP Heart Failure trial: A randomized controlled pivotal trial of high-dose autologous bone marrow mononuclear cells using the CardiAMP cell therapy system in patients with post-myocardial infarction heart failure: Trial rationale and study design.

BACKGROUND: Heart failure following myocardial infarction is a common, disabling, and deadly condition. Direct injection of autologous bone marrow mononuclear cells into the myocardium may result in improved functional recovery, relieve symptoms, and improve other cardiovascular outcomes. METHODS: CardiAMP-HF is a randomized, double-blind, sham-controlled, pivotal trial designed to investigate the safety and efficacy of autologous bone marrow mononuclear cells treatment for patients with medically refractory and symptomatic ischemic cardiomyopathy. The primary end point is change in 6-minute walk distance adjusted for major adverse cardiovascular events at 12 months following treatment. Particularly novel aspects of this trial include a cell potency assay to screen subjects who have bone marrow cell characteristics that suggest a favorable response to treatment, a point-of-care treatment method, a high target dose of 200 million cells, and an efficient transcatheter intramyocardial delivery method that is associated with high cell retention. CONCLUSIONS: This novel approach may lead to a new treatment for those with ischemic heart disease suffering from medically refractory heart failure.

Rationale and Design of the SENECA (StEm cell iNjECtion in cAncer survivors) Trial.

OBJECTIVES: SENECA (StEm cell iNjECtion in cAncer survivors) is a phase I, randomized, double-blind, placebo-controlled study to evaluate the safety and feasibility of delivering allogeneic mesenchymal stromal cells (allo-MSCs) transendocardially in subjects with anthracycline-induced cardiomyopathy (AIC). BACKGROUND: AIC is an incurable and often fatal syndrome, with a prognosis worse than that of ischemic or nonischemic cardiomyopathy. Recently, cell therapy with MSCs has emerged as a promising new approach to repair damaged myocardium. METHODS: The study population is 36 cancer survivors with a diagnosis of AIC, left ventricular (LV) ejection fraction ≤40%, and symptoms of heart failure (NYHA class II-III) on optimally-tolerated medical therapy. Subjects must be clinically free of cancer for at least two years with a ≤ 30% estimated five-year risk of recurrence. The first six subjects participated in an open-label, lead-in phase and received 100 million allo-MSCs; the remaining 30 will be randomized 1:1 to receive allo-MSCs or vehicle via 20 transendocardial injections. Efficacy measures (obtained at baseline, 6 months, and 12 months) include MRI evaluation of LV function, LV volumes, fibrosis, and scar burden; assessment of exercise tolerance (six-minute walk test) and quality of life (Minnesota Living with Heart Failure Questionnaire); clinical outcomes (MACE and cumulative days alive and out of hospital); and biomarkers of heart failure (NT-proBNP). CONCLUSIONS: This is the first clinical trial using direct cardiac injection of cells for the treatment of AIC. If administration of allo-MSCs is found feasible and safe, SENECA will pave the way for larger phase II/III studies with therapeutic efficacy as the primary outcome.

Revascularization in "no option" patients with refractory angina: Frequency, etiology and outcomes.

BACKGROUND: A significant proportion of patients with complex, advanced coronary artery disease have refractory angina (RA) despite maximal pharmacological therapy and are deemed suboptimal candidates for revascularization. These patients are frequently termed "no-option" patients. However, despite this designation, many subsequently undergo coronary revascularization. We sought to determine the incidence, etiology and outcome of revascularization in "no-option" patients. METHODS AND RESULTS: We examined a comprehensive, prospective RA database to identify 342 of 1363 (25.1%) patients who subsequently underwent revascularization after a median interval of 2.2 years from the "no-option" diagnosis. Coronary revascularization was achieved by percutaneous coronary intervention (PCI) (n = 274, 20.1%), coronary bypass graft surgery (n = 44, 3.2%) or both (n = 24, 1.8%). During a median follow-up of 5.1 years, patients who underwent revascularization had lower annual mortality (2% vs. 4.4%, P < .001). Detailed paired angiographic records were available for 181 PCI patients with a combined 302 lesions. Of these interventions, 48% were for a new lesion, 31% for an existing lesion and 21% for restenosis. The location was a native vessel in 77% and a bypass graft in 23%. CONCLUSIONS: The "no-option" or non-revascularizable designation is frequently based on angiography at a single time-point. However, coronary artery disease is a progressive and dynamic process and new lesions often develop in such patients. Given the association between revascularization and better survival, careful consideration should be given to repeat revascularization in patients with refractory angina previously classified as "no-option".