Misdiagnosed Aortic Intramural Hematoma and the Role of Intravascular Ultrasound Imaging in Detection of Acute Aortic Syndrome:A Case Report

Acute aortic syndrome includes classic aortic dissection,aortic intramural hematoma,and penetrating atherosclerotic ulcer– a group of conditions that are defined by their dynamic evolution and similar clinical manifestation.Accurate diagnosis and prompt treatment are essential as all the aforementioned conditions are a signifi cant threat to a patient’s life.However,acute aortic syndrome and especially aortic intramural hematoma may be challenging diagnostic problems.Intravascular ultrasound imaging is a diagnostic method that can be useful for more thorough evaluation of the aortic lesion and can particularly aid in discerning the different forms of acute aortic syndrome.We present a case of a patient with aortic intramural hematoma that was missed by conventional imaging studies but was successfully visualized with intravascular ultrasound imaging.

Changes in coronary bifurcations after stent placement in the main vessel and balloon opening of stent cells:theory and practical verification on a bench-test model

Objective To describe changes that occur in stent morphology and structure after its implantation in coronary bifurcation.Side branch (SB) compromise after stenting of main vessel in coronary bifurcation is a major intraprocedural problem and for the long term,as a place of restenosis.Methods We created an elastic wall model (parent vessel diameter 3.5mm,daughter branches 3.5mm and 2.75mm)with 30,45 and 60 degree distal angulation between branches.After stent implantation,struts to the side branch were opened with 2.0mm and consequently 3.0mm diameter balloons.Subsequent balloon redilatations and kissing balloon inflations (KBI) were performed.All stages of the procedure were photographed with magnification up to 100 times.Results We found that the leading mechanism for side branch compromise was carina displacement,and discovered theoretical description for expected ostial stenosis severity.Based on our model we found that displacement of bifurcation flow divider cause SB stenosis with almost perfect coincidence with our theoretical predictions.Opening of stent cells through the proximal and distal stent struts always increased interslrut distance,but never achieved good apposition to the wall.Balloon diameter increase didn't give proportional enlargement in stent cell diameters.KBI leads to some small better stent positioning,correcting main vessel strut dislodgment from wall,but never gave full strut-wall contact.Distance between struts and wall was minimal only when the stent cell perfectly faced ostium of SB.This was also our observation that the shape of ostium of SB becomed eUiptically-bean shaped after stent implantation and generally kept that shape during consequent stages of experiment.Measured diameter and area stenosis were perfectly fitted and theoretically predicted from our concept Conclusion We have described stent-wall deformations in stent-balloon technique for treatment of coronary bifurcation demonstrating carina displacement as possibly main mechanism of side branch compromise after main vessel stenting.We have shown that KBI could not give full strut-wall contact if there is no perfect facing of stem cell and SB ostium.(J Geroatr Cardool 2008;5(1):43-49)

Theoretical prediction of side branch compromise after main branch stenting in coronary bifurcation

One of the main problems of treatment of bifurcation lesions is side branch (SB) stenosis appearing after stent placement in the main vessel. The aim of this study was to create quantitative method for prediction of side branch compromise extent. We accepted that the main mechanism for SB ostial stenosis is flow divider (FD) displacement from stent struts after stent implantation in the main vessel. Using easily measurable parameters from coronary angiography, as SB diameter, angle á (initial angle between axes of parent vessel and SB axis) and angle á' (angle between above mentioned axes after stent placement) we can calculate percentage diameter stenosis at branch ostium (%DS): %DS = sin (á - á')/(tan á). In boundary condition of full FD displacement %DS = cos á. We tested our theoretical predictions with fluoroscopic observation of elastic wall model of bifurcation (45o distal angle between branches) permitting wall deformations with stent. There is full coincidence of values of %DS and percentage area stenosis (%AS). The regular formulas for calculations of %DS and %AS overestimate stenosis severity between 10% and 25%. Our model tests have shown full coincidence between predicted values for %DS and observed values. We demonstrate that part of the SB ostium is not visible in regular angiography and contributes to ostial lumen area. This is a method that permits quantitative prediction of side branch compromise.