Compared to standard measures, IMR appears to be a better predictor of microvascular damage after STEMI, both acutely and in short term follow-up.

No abstract

Female gender, low BSA, and higher femoral artery puncture are significant risk factors for RPH. Awareness of the determinants and clinical features of RPH may aid in prevention, early recognition, and prompt treatment.

TMVR with the valve was feasible in a study group at high or extreme risk for conventional mitral valve replacement. These results inform trial design of TMVR in lower-risk patients with severe mitral valve regurgitation (Evaluation of the Safety and Performance of the Twelve Intrepid Transcatheter Mitral Valve Replacement System in High Risk Patients with Severe, Symptomatic Mitral Regurgitation - The Twelve Intrepid TMVR Pilot Study; NCT02322840).

Background-A simple, reproducible invasive method for assessing the coronary microcirculation is lacking. A novel index of microcirculatory resistance (IMR) has been shown in animals to correlate with true microvascular resistance and, unlike coronary flow reserve (CFR), to be independent of the epicardial artery. We sought to compare the reproducibility and hemodynamic dependence of IMR with CFR in humans. Methods and Results-Using a pressure-temperature sensor-tipped coronary wire, thermodilution-derived CFR and IMR were measured, along with fractional flow reserve (FFR), in 15 coronary arteries (15 patients) under the following hemodynamic conditions: (1) twice at baseline; (2) during right ventricular pacing at 110 bpm; (3) during intravenous infusion of nitroprusside; and (4) during intravenous dobutamine infusion. Mean CFR did not change during baseline measurements or during nitroprusside infusion but decreased during pacing (from 3.1Ϯ1.1 at baseline to 2.3Ϯ1.2 during pacing, PϽ0.05) and during dobutamine infusion (from 3.0Ϯ1.0 to 1.7Ϯ0.6 with dobutamine, PϽ0.0001). By comparison, mean values for IMR and FFR remained similar throughout all hemodynamic conditions. The mean coefficient of variation between 2 baseline measurements was significantly lower for IMR (6.9Ϯ6.5%) and FFR (1.6Ϯ1.6%) than for CFR (18.6Ϯ9.6%; PϽ0.01). Mean correlation between baseline measurements and each hemodynamic intervention was superior for IMR (rϭ0.90Ϯ0.05) and FFR (rϭ0.86Ϯ0.12) compared with CFR (rϭ0.70Ϯ0.05; PϽ0.05). Conclusions-Compared with CFR, IMR provides a more reproducible assessment of the microcirculation, which is independent of hemodynamic perturbations. Simultaneous measurement of FFR and IMR may provide a comprehensive and specific assessment of coronary physiology at both epicardial and microvascular levels, respectively. (Circulation.

A novel EC-specific tubulogenesis assay highlights strikingly different angiogenic properties of different EPCs: late OECs directly participate in tubulogenesis, whereas early EPCs augment angiogenesis in a paracrine fashion, with implications for optimizing cell therapies for neovascularization.

Wound healing and repair are the most complex biological processes that occur in human life. After injury, multiple biological pathways become activated. Impaired wound healing, which occurs in diabetic patients for example, can lead to severe unfavorable outcomes such as amputation. There is, therefore, an increasing impetus to develop novel agents that promote wound repair. The testing of these has been limited to large animal models such as swine, which are often impractical. Mice represent the ideal preclinical model, as they are economical and amenable to genetic manipulation, which allows for mechanistic investigation. However, wound healing in a mouse is fundamentally different to that of humans as it primarily occurs via contraction. Our murine model overcomes this by incorporating a splint around the wound. By splinting the wound, the repair process is then dependent on epithelialization, cellular proliferation and angiogenesis, which closely mirror the biological processes of human wound healing. Whilst requiring consistency and care, this murine model does not involve complicated surgical techniques and allows for the robust testing of promising agents that may, for example, promote angiogenesis or inhibit inflammation. Furthermore, each mouse acts as its own control as two wounds are prepared, enabling the application of both the test compound and the vehicle control on the same animal. In conclusion, we demonstrate a practical, easy-to-learn, and robust model of wound healing, which is comparable to that of humans.

The development of an ideal small-diameter conduit for use in vascular bypass surgery has yet to be achieved. The ongoing innovation in biomaterial design generates novel conduits that require preclinical assessment in vivo, and a number of animal models have been used for this purpose. This article examines the rationale behind animal models used in the assessment of small-diameter vascular conduits encompassing the commonly used species: baboons, sheep, pigs, dogs, rabbits, and rodents. Studies on the comparative hematology for these species relative to humans are summarized, and the hydrodynamic values for common implant locations are also compared. The large- and small-animal models are then explored, highlighting the characteristics of each that determine their relative utility in the assessment of vascular conduits. Where possible, the performance of expanded polytetrafluoroethylene is given in each animal and in each location to allow direct comparisons between species. New challenges in animal modeling are outlined for the assessment of tissue-engineered graft designs. Finally, recommendations are given for the selection of animal models for the assessment of future vascular conduits.