Ram Vijayaraghavan

Rescue Angioplasty or Repeat Fibrinolysis After Failed Fibrinolytic Therapy for ST-Segment Myocardial Infarction A Meta-Analysis of Randomized Trials

OBJECTIVES We sought to best estimate the benefits and risks associated with rescue percutaneous coronary intervention (PCI) and repeat fibrinolytic therapy as compared with conservative management in patients with failed fibrinolytic therapy for ST-segment myocardial infarction (STEMI). BACKGROUND Fibrinolytic therapy is the most common treatment for STEMI; however, the best therapy in patients who fail to achieve reperfusion after fibrinolytic therapy remains uncertain. METHODS We performed a meta-analysis of randomized trials using a fixed-effects model. We included 8 trials enrolling 1,177 patients with follow-up duration ranging from hospital discharge to 6 months. RESULTS Rescue PCI was associated with no significant reduction in all-cause mortality (relative risk [RR] 0.69; 95% confidence interval [CI] 0.46 to 1.05), but was associated with significant risk reductions in heart failure (RR 0.73; 95% CI 0.54 to 1.00) and reinfarction (RR 0.58; 95% CI 0.35 to 0.97) when compared with conservative treatment. Rescue PCI was associated with an increased risk of stroke (RR 4.98; 95% CI 1.10 to 22.5) and minor bleeding (RR 4.58; 95% CI 2.46 to 8.55). Repeat fibrinolytic therapy was not associated with significant improvements in all-cause mortality (RR 0.68; 95% CI 0.41 to 1.14) or reinfarction (RR 1.79; 95% CI 0.92 to 3.48), but was associated with an increased risk for minor bleeding (RR 1.84; 95% CI 1.06 to 3.18). CONCLUSIONS Rescue PCI is associated with improved clinical outcomes for STEMI patients after failed fibrinolytic therapy, but these benefits must be interpreted in the context of potential risks. On the other hand, repeat fibrinolytic therapy is not associated with significant clinical improvement and may be associated with increased harm.

Clinical ResearchInterventional CardiologyRescue Angioplasty or Repeat Fibrinolysis After Failed Fibrinolytic Therapy for ST-Segment Myocardial Infarction: A Meta-Analysis of Randomized Trials

OBJECTIVES We sought to best estimate the benefits and risks associated with rescue percutaneous coronary intervention (PCI) and repeat fibrinolytic therapy as compared with conservative management in patients with failed fibrinolytic therapy for ST-segment myocardial infarction (STEMI). BACKGROUND Fibrinolytic therapy is the most common treatment for STEMI; however, the best therapy in patients who fail to achieve reperfusion after fibrinolytic therapy remains uncertain. METHODS We performed a meta-analysis of randomized trials using a fixed-effects model. We included 8 trials enrolling 1,177 patients with follow-up duration ranging from hospital discharge to 6 months. RESULTS Rescue PCI was associated with no significant reduction in all-cause mortality (relative risk [RR] 0.69; 95% confidence interval [CI] 0.46 to 1.05), but was associated with significant risk reductions in heart failure (RR 0.73; 95% CI 0.54 to 1.00) and reinfarction (RR 0.58; 95% CI 0.35 to 0.97) when compared with conservative treatment. Rescue PCI was associated with an increased risk of stroke (RR 4.98; 95% CI 1.10 to 22.5) and minor bleeding (RR 4.58; 95% CI 2.46 to 8.55). Repeat fibrinolytic therapy was not associated with significant improvements in all-cause mortality (RR 0.68; 95% CI 0.41 to 1.14) or reinfarction (RR 1.79; 95% CI 0.92 to 3.48), but was associated with an increased risk for minor bleeding (RR 1.84; 95% CI 1.06 to 3.18). CONCLUSIONS Rescue PCI is associated with improved clinical outcomes for STEMI patients after failed fibrinolytic therapy, but these benefits must be interpreted in the context of potential risks. On the other hand, repeat fibrinolytic therapy is not associated with significant clinical improvement and may be associated with increased harm.

Inversion‐recovery‐prepared SSFP for cardiac‐phase‐resolved delayed‐enhancement MRI

Delayed‐enhancement magnetic resonance imaging (DE‐MRI) can be used to visualize myocardial infarction (MI). DE‐MRI is conventionally acquired with an inversion‐recovery gradient‐echo (IR‐GRE) pulse sequence that yields a single bright‐blood image. IR‐GRE imaging requires an accurate estimate of the inversion time (TI) to null the signal from the myocardium, and a separate cine acquisition is required to visualize myocardial wall motion. Simulations were performed to examine the effects of a steady‐state free precession (SSFP) readout after an inversion pulse in the setting of DE‐MRI. Using these simulations, a segmented IR‐SSFP sequence was optimized for infarct visualization. This sequence yields both viability and wall motion images over the cardiac cycle in a single breath‐hold. Viability images at multiple effective TIs are produced, providing a range of image contrasts. In a study of 11 patients, IR‐SSFP yielded infarct sizes and left ventricular ejection fractions (LVEFs) similar to those obtained by IR‐GRE and standard SSFP, respectively. IR‐SSFP images yielded improved visualization of the infarct‐blood border because of the simultaneous nulling of healthy myocardium and blood. T  1* recovery curves were extracted from IR‐SSFP images and showed excellent qualitative agreement with theoretical simulations. Magn Reson Med 58:365–372, 2007.

Long-term tracking of bone marrow progenitor cells following intracoronary injection post-myocardial infarction in swine using MRI

Magnetic resonance imaging (MRI) can track progenitor cells following direct intramyocardial injection. However, in the vast majority of post-myocardial infarction (MI) clinical trials, cells are delivered by the intracoronary (IC) route, which results in far greater dispersion within the myocardium. Therefore, we assessed whether the more diffuse distribution of cells following IC delivery could be imaged longitudinally with MRI. In 11 pigs (7 active, 4 controls), MI was induced by 90-min balloon occlusion of the left anterior descending coronary artery. Seven (0) days [median (interquartile range)] following MI, bone marrow progenitor cells (BMCs) were colabeled with an iron-fluorophore and a cell viability marker and delivered to the left anterior descending coronary artery distal to an inflated over-the-wire percutaneous transluminal coronary angioplasty balloon. T2*-weighted images were used to assess the location of the magnetically labeled cells over a 6-wk period post-MI. Immediately following cell delivery, hypointensity characteristic of the magnetic label was observed in the infarct border rather than within the infarct itself. At 6 wk, the cell signal hypointensity persisted, albeit with significantly decreased intensity. BMC delivery resulted in significant improvement in infarct volume and ejection fraction (EF): infarct volume in cell-treated animals decreased from 7.1 +/- 1.5 to 4.9 +/- 1.0 ml (P < 0.01); infarct volume in controls was virtually unchanged at 4.64 +/- 2.1 to 4.39 +/- 2.1 ml (P = 0.7). EF in cell-treated animals went from 30.4 +/- 5.2% preinjection to 34.5 +/- 2.5% 6 wk postinjection (P = 0.013); EF in control animals went from 34.3 +/- 4.7 to 31.9 +/- 6.8% (P = 0.5). Immunohistochemical analysis revealed intracellular colocalization of the iron fluorophore and cell viability dye with the labeled cells continuing to express the same surface markers as at baseline. MRI can track the persistence and distribution of magnetically labeled BMCs over a 6-wk period following IC delivery. Signal hypointensity declines with time, particularly in the first week following delivery. These cells maintain their original phenotype during this time course. Delivery of these cells appears safe and results in improvement in infarct size and left ventricular ejection fraction.

Free-breathing, nongated real-time delayed enhancement MRI of myocardial infarcts: A comparison with conventional delayed enhancement

To compare a free‐breathing, nongated, and black‐blood real‐time delayed enhancement (RT‐DE) sequence to the conventional inversion recovery gradient echo (IR‐GRE) sequence for delayed enhancement MRI.

Pharmacodynamic and clinical implications of switching between P2Y12 receptor antagonists: considerations for practice.

Dual antiplatelet therapy with aspirin and a P2Y12 receptor antagonist, either clopidogrel or the newer more potent agents prasugrel or ticagrelor, is standard therapy in patients receiving a coronary stent and those with a recent acute coronary syndrome. Switching antiplatelet drug regimen may be required in some patients for efficacy, safety, adherence, and cost considerations. However, there are potential concerns when switching from one agent to another that gaps in effective antiplatelet inhibition could lead to thrombotic events, and overlap of agents might cause excessive platelet inhibition thereby increasing the risk of bleeding. This review considers pharmacodynamic and clinical data to guide clinicians when switching between antiplatelet drugs is considered. Loading dose of the new agent should be considered in nearly all situations to avoid any possible gap in adequate platelet inhibition, as overlap of the 2 agents is unlikely to result in bleeding in excess of that with the more potent drug.