Emergent right coronary artery thrombectomy with a jet aspiration thrombectomy catheter

Co-localization of von Willebrand factor with platelet thrombi, tissue factor and platelets with fibrin, and consistent presence of inflammatory cells in coronary thrombi obtained by an aspiration device from patients with acute myocardial infarction

BACKGROUND

Detailed histochemical analysis of coronary thrombi obtained freshly from acute phase of myocardial infarction patients may provide information necessary to understand the mechanism of coronary occlusive thrombus formation.

METHODS AND RESULTS

Coronary thrombi causing myocardial infarction were obtained from 10 consecutive patients of myocardial infarction in the acute phase, using a newly developed aspiration catheter. All the fixed specimens of coronary thrombi, by hematoxylin and eosin staining, were found to contain three major constituents, namely, platelets, densely packed fibrin and inflammatory cells, including polymorphonuclear and mononuclear cells, although their distribution in each specimen is totally heterogeneous. Immunohistochemical staining revealed the prominent presence of von Willebrand factor (VWF) at the sites of platelet accumulation, presence of tissue factor and platelets at the sites of deposition of fibrin fibrils. It also revealed the presence of CD16-, CD45- and CD34-positive cells, yet the functional roles of these cells have still to be elucidated. There are weak positive correlation between the number of inflammatory cells involved in the unit area of coronary thrombi specimen and the time of collection of the specimens after the onset of chest pain.

CONCLUSIONS

In spite of various limitations, our results contain information suggesting the possible role of VWF in platelet-thrombus formation, possible important role played by tissue factor and activated platelets in the formation of fibrin fibrils, and the positive relationship between inflammatory cells migration and the formation of occlusive thrombi in human coronary arteries.

Hydraulic analysis of the functional properties of saline-jet aspiration thrombectomy catheters

The purpose of this paper is to clarify the functional properties of a saline-jet aspiration thrombectomy catheter based on hydraulics. This catheter, developed by the authors, aspirates intravascular thrombi by means of the effect of a high-speed jet. We have derived the relationships between Qs, Qa, and p(n), where Qs is the water supply rate, Qa is the water aspiration rate and p(n) is the negative pressure created in the distal lumen of the catheter. The relationships are represented by simple equations using c1 and c2, where c1 and c2 are coefficients proper to the catheter. We have obtained c1 and c2 experimentally for three types of catheter with different distal shapes. Two practical conclusions are derived from this study. First, making a short taper at the distal end increases the negative pressure created and is advantageous for thrombus aspiration. Second, making the diameter of the inner tube and nozzle smaller is essential for improving the aspiration ability of the catheter.