Predictors and clinical impact of pre-existing and acquired thrombocytopenia following transcatheter aortic valve replacement.

BACKGROUND: Data are limited regarding transcatheter aortic valve replacement (TAVR)-related thrombocytopenia (TP). We sought to thoroughly characterize the presence, clinical impact, and severity of TP associated with TAVR. METHODS AND RESULTS: Data were collected from 90 patients who underwent TAVR using the Edwards SAPIEN valve (59 TF, 29 TA, 2 Tao). Platelet counts were evaluated peri-procedurally and for 8 days following TAVR. Platelet levels were compared and patients were divided into a no TP (No-TP) group 1, acquired (new) TP (NTP) group 2, pre-existing (pre-TAVR) TP (PTP) group 3, and further stratified based on the severity of TP: mild (M) TP (100-149 × 10(3) cell/µL) and moderate-severe (MS) TP (<100 × 10(3) cell/µL). Pre-TAVR point prevalence and post-TAVR incidence of TP were 40% and 79%, respectively (P < 0.001); nadir platelet count in all groups occurred day 4 post-TAVR. Baseline predictors for developing MS TP in groups 2-3 included baseline TP, leaner body mass, smaller pre-procedural aortic valve area, higher peak aortic jet velocity, and worsening baseline renal function. Development of "major" TP (nadir platelet count <100 × 103 cell/µL, ≥50% decrease) predicted a higher risk of major vascular complications (OR 2.78 [95% CI, 1.58-3.82]) and major bleeding (OR 3.18 [95% CI, 1.33-5.42]) in group 3. CONCLUSION: TAVR-related TP is predictable and classification by PTP and TP severity prior to TAVR allows for better risk stratification in predicting in-hospital clinical outcomes. Major TP in the presence of worsening TP is predictable and is associated with worse clinical outcomes. © 2014 Wiley Periodicals, Inc.

Snake Envenomation Simulating ST Elevation Myocardial Infarction.

Envenomation syndromes following snakebites can include tissue reaction, coagulopathy, nephrotoxicity, and neurotoxicity. Cardiotoxicity is rare but usually presents with dysrhythmias. Myocardial infarction after envenomation has rarely been reported. We discuss a case of snake bite simulating ST-elevation myocardial infarction (STEMI). Our patient is a 49-year-old male who sustained a snake bite in his left hand. Patient had hemodynamic collapse requiring increasing pressor support; EKG and troponin results confirmed STEMI. Cardiac catheterization did not demonstrate any thrombosis, rather severe cardiomyopathy with left ventricular ejection fraction 20-25%. Even though our patient did not require any coronary intervention, an angiogram was warranted given the clinical presentation. Our case demonstrates severe cardiotoxicity following snake bite. Further research is warranted to study the mechanism behind such phenomena.

Myocardial Infarction Secondary to Left Internal Mammary Artery Graft Occlusion After Left Subclavian Bypass.

Cardiogenic shock is a severe, often fatal presentation of acute myocardial infarction. This report presents an unusual case of ST-segment elevation myocardial infarction with left internal mammary artery occlusion occurring after instrumentation of the left subclavian artery as part of planned repair of a complex aortic aneurysm. (Level of Difficulty: Advanced.).

Long-Term Efficacy and Safety of Everolimus-Eluting Bioresorbable Vascular Scaffolds Versus Everolimus-Eluting Metallic Stents: A Meta-Analysis of Randomized Trials.

BACKGROUND: Data regarding the long-term efficacy and safety of everolimus-eluting bioresorbable vascular scaffolds (BVS) compared with everolimus-eluting stents are limited. This meta-analysis aimed to compare the long-term outcomes with both devices. METHODS AND RESULTS: Randomized trials reporting clinical outcomes beyond 1 year and comparing BVS with everolimus-eluting stents were included. Summary estimates risk ratios (RRs) were constructed. The primary efficacy outcome was target lesion failure, defined as cardiac death, target vessel myocardial infarction, and ischemia-driven target lesion revascularization, and the primary safety outcome was definite or probable stent/scaffold thrombosis. Six trials with 5392 patients were included (mean follow-up, 25 months). BVS had a higher rate of target lesion failure (RR, 1.33; 95% confidence interval [CI], 1.11-1.58) driven by the higher rates of target vessel myocardial infarction (RR, 1.65; 95% CI, 1.26-2.17) and target lesion revascularization (RR, 1.39; 95% CI, 1.08-1.78). The risk of definite or probable stent/scaffold thrombosis (RR, 3.22; 95% CI, 1.89-5.49) and very late stent/scaffold thrombosis (>1 year; RR, 4.78; 95% CI, 1.66-13.8) was higher with BVS. The risk of cardiac and all-cause mortality was similar in both groups. CONCLUSIONS: Compared with everolimus-eluting stents, BVS is associated with increased risk of target lesion failure driven by the increased rates of target vessel myocardial infarction and ischemia-driven target lesion revascularization in these studies (mean follow-up, 25 months). The risk of definite or probable stent/scaffold thrombosis and very late stent/scaffold thrombosis seems to be higher with BVS. Further information from randomized trials is critical to evaluate clinical outcomes with BVS on complete resolution of the scaffold.

The microfluidic multitrap nanophysiometer for hematologic cancer cell characterization reveals temporal sensitivity of the calcein-AM efflux assay.

Cytometric studies utilizing flow cytometry or multi-well culture plate fluorometry are often limited by a deficit in temporal resolution and a lack of single cell consideration. Unfortunately, many cellular processes, including signaling, motility, and molecular transport, occur transiently over relatively short periods of time and at different magnitudes between cells. Here we demonstrate the multitrap nanophysiometer (MTNP), a low-volume microfluidic platform housing an array of cell traps, as an effective tool that can be used to study individual unattached cells over time with precise control over the intercellular microenvironment. We show how the MTNP platform can be used for hematologic cancer cell characterization by measuring single T cell levels of CRAC channel modulation, non-translational motility, and ABC-transporter inhibition via a calcein-AM efflux assay. The transporter data indicate that Jurkat T cells exposed to indomethacin continue to accumulate fluorescent calcein for over 60 minutes after calcein-AM is removed from the extracellular space.