Lukasz Kalinczuk

Volumetric intravascular ultrasound evidence that distal embolization during acute infarct intervention contributes to inadequate myocardial perfusion grade.

We studied 35 consecutive patients with myocardial infarction (MI) who were treated with direct infarct percutaneous coronary intervention (PCI) using standard angiographic (complete assessment of flow grade and blush grade) and pre- and post-PCI volumetric intravascular ultrasound analysis. Plaque reduction, which is evidence of distal embolization, contributes to inadequate tissue reperfusion in this lesion setting and supports the use of distal protection in the setting of an acute MI.

Comparison of Usefulness of Percutaneous Coronary Intervention Guided by Angiography plus Computed Tomography Versus Angiography Alone Using Intravascular Ultrasound End Points

The aim of our study was to assess the impact of coronary computed tomographic angiographic (CTCA) guidance on outcomes of percutaneous coronary intervention (PCI). The study was a randomized single-center trial. Consecutive eligible patients with CTCA-detected significant coronary lesions who were scheduled for PCI were randomized to an angiographically guided versus an angiographically plus computed tomographically guided (ACTG) group. In the ACTG group the operator preliminarily planned PCI based on computed tomographic angiogram. The coprimary end points were minimal stent area and minimal reference lumen area assessed in all patients with intravascular ultrasound performed after achieving optimal angiographic results. Seventy-one patients (50 men, mean age 65 ± 8 years) were randomized. After invasive angiography, PCI of 32 lesions (30 patients) in the ACTG and in 32 lesions (30 patients) in the angiographically guided group was performed. A stented segment length was longer and nominal stent diameter tended to be larger in the ACTG group (23.8 ± 6.7 vs 19.5 ± 6.5 mm, p = 0.01; 3.27 ± 0.44 vs 3.09 ± 0.41 mm(2), p = 0.110). Minimal stent area tended to be larger (6.62 ± 2.01 vs 5.80 ± 2.02 mm(2), p = 0.100) and the smallest peri-stent reference lumen area was significantly larger in the ACTG group (6.76 ± 3.01 vs 5.0 ± 1.62 mm(2), p = 0.006) with a smaller plaque burden (50 ± 16% vs 58 ± 13%, p = 0.025). In conclusion, CTCA analysis before PCI significantly influences treatment strategy and results in better lesion coverage as defined by intravascular criteria.

Dose volume histogram assessment of late stent malapposition after intravascular brachytherapy.

PURPOSE Positive remodeling and decreased neointima proliferation are among the causes for Late Stent Malapposition (LSM). It was our interest to investigate a possible relationship between dose and incidence of LSM. METHODS Index and follow up IVUS examinations of 238 patients (152 treated with Intravascular Brachytherapy (IVBT), 86 control) enrolled in IVBT trials were reviewed to identify patients with LSM. 7.2% of patients treated with IVBT and 2.3% of patients in the control group were found to have LSM on their 6-month follow-up IVUS. Using the index IVUS study. Dose Volume Histograms (DVH) were constructed for a segment of the adventitia comprising an arc deep to the area where LSM is present at follow up. For control, two areas: an arc deep to complete apposition (Control 1) and a segment within the stent but 5 mm apart from the LSM (Control 2). Volumes were defined by IVUS images that were 1 mm apart and the media-adventitial contour was taken to be 0.5 mm thick from the border. RESULTS DVH of 90% and 50% adventitial volume of LSM area received a significantly (p < .05) higher dose compared to both controls. Calculated are 12 LSM sites in 9 patients and 9 control sites. At all 12 sites Mean Cross Sectional Area of External Elastic Membrane (EEM CSA) was significantly larger in the LSM group at follow up compared to index (p-.001). CONCLUSIONS DVH analysis showed a positive correlation between radiation dose to the adventitia and incidence of LSM. The myofibroblasts in the adventitia are known to be the target for irradiation. Proliferation of myofibroblasts leads to neointima formation. LSM may be due to the higher dosages delivered to 50% and 90% of the adventitia volume (LSM area) which may have led to profound neointima suppression. In turn the neointima could not compensate positive remodeling reflected by an increase in EEM CSA.

Comparison of Intravascular Ultrasound, Quantitative Coronary Angiography, and Dual-Source 64-Slice Computed Tomography in the Preprocedural Assessment of Significant Saphenous Vein Graft Lesions

The correlation between cardiac computed tomographic (CT) and intravascular ultrasound (IVUS) assessment of saphenous vein graft (SVG) lesions has not been studied. The aim of this study was to evaluate the accuracy of dual-source computed tomography in quantitative assessment of significant SVG lesions scheduled for percutaneous coronary intervention (PCI). Preintervention dual-source CT (DSCT) scans were performed in consecutive patients before PCI of the SVG lesion. All subjects underwent IVUS examination of the target lesion before stent implantation. Lesion characteristics were described using dual-source computed tomography, quantitative coronary angiography, IVUS, and visual estimation. Luminal areas and diameters, lesion lengths, and DSCT suggested stent dimensions were compared. Twenty-two SVG lesions were assessed in 22 patients. Minimal lumen area measured by IVUS was larger than by dual-source computed tomography (3.5 ± 1.2 vs 3.0 ± 1.2 mm(2), p = 0.04), although there was close correlation between measurements (R = 0.7, p = 0.007). Proximal and distal reference lumen diameters by IVUS and dual-source computed tomography were similar (3.3 ± 0.4 vs 3.4 ± 0.6 mm, p = 0.5, and 3.4 ± 0.6 vs 3.5 ± 0.6 mm, p = 0.4, respectively) and were well correlated (R = 0.85, p <0.0001, and R = 0.81, p <0.0001, respectively). Lesion length by IVUS averaged 18.3 ± 6.1 versus 17.6 ± 5.3 mm by dual-source computed tomography (p = 0.1). There was good correlation between mean reference lumen diameter by dual-source computed tomography and diameter of the implanted stent (R = 0.84, p = 0.0009) and a very good correlation between stent length and lesion length as assessed by dual-source computed tomography (R = 0.9, p <0.0001). In conclusion, DSCT measurements in SVGs correlate with IVUS so that DSCT scan data before PCI of an SVG lesion may be helpful in stent size selection.

Incidence and mechanism of late stent malapposition after phosphorus-32 radioactive stent implantation

Late stent malapposition is a potential complication of intracoronary brachytherapy. The aim of our study was to determine the incidence and mechanism of late stent malapposition after implantation of phosphorus-32 radioactive stents. We analyzed 159 patients for de novo lesions after the implantation of phosphorus-32 radioactive stents. There were 15 late stent malappositions. The incidence of malapposition was higher in patients who received Hot-Ends Isostents. External elastic membrane expansion greater than plaque increase in malapposed segments was observed. Late stent malapposition is caused by a localized increase in external elastic membrane that is greater than the increase in plaque area; this is believed to be a dose-dependent phenomenon because it was more common with Hot-Ends Isostents.

Relation of Drug-Eluting Stent Strut Distribution to Stent Thrombosis in Coronary Arteries

The distribution of stent struts is critical to drug deposition and, therefore, may affect the amount of neointima and the risk of thrombosis after drug-eluting stent (DES) implantation. The aim of our study was to evaluate stent strut distribution in the setting of a drug-eluting stent thrombosis (ST). We retrospectively analyzed postprocedural intravascular ultrasound (IVUS) images of 13 patients who subsequently developed ST (14 DES thrombotic lesions) and a control group of 27 patients (30 DES lesions) matched for stent type and presence of chronic renal failure. In addition to standard IVUS measurements, visible struts were counted and maximum interstrut angle was measured at 1-mm intervals. Early ST was defined as < or =30 days after DES deployment and late ST as >30 days after DES deployment. Compared with DES controls, the ST group had a larger maximum interstrut angle (60.8 +/- 8.3 degrees vs 55.7 +/- 4.8 degrees , p = 0.014) and a similar number of stent struts (8.4 +/- 0.6 vs 8.7 +/- 0.6, p = NS). Maximum interstrut angle tended to be larger in late ST than in early ST (66.1 +/- 10.8 degrees vs 57.8 +/- 5.0 degrees , p = 0.071). The incidence of maximum interstrut angles > or =90 degrees and > or =120 degrees observed continuously for > or =2 mm of stent length was higher in the ST group (p = 0.009 and p = 0.096, respectively). In conclusion, DES-treated lesions leading to ST had larger maximum interstrut gaps distributed circumferentially and longitudinally, but a similar number of struts at the time of DES implantation compared with DES controls.

Comparison of Stent Length Reported by the Stent's Manufacturer to That Determined by Quantitative Coronary Angiography at the Time of Implantation Versus That Determined by Coronary Computed Tomographic Angiography at a Later Time

The aim of this study was to assess whether coronary computed tomographic angiography (CCTA) would allow accurate length measurements that may help select optimal stent length. In 19 patients who underwent stent implantation and CCTA, the lengths of 30 implanted stents were assessed independently using quantitative coronary angiography (QCA) at the time of implantation and CCTA during follow-up. Measurements on CCTA and QCA were compared with the actual lengths of the implanted stents. The mean actual stent length was 17.3 ± 6.3 mm; the mean length of the stents measured using CCTA was 17.25 ± 5.54 mm, and the mean length of the stents measured using QCA was 15.92 ± 5.86 mm. There was a stronger positive correlation between measurements on CCTA versus actual stent lengths (R = 0.99, p = 0.0001) than between measurements on QCA versus actual stent lengths (R = 0.82, p = 0.0001) (p <0.0001 for the difference between correlation coefficients). In conclusion, the length measurements obtained with CCTA correlate better with an anatomic gold standard (actual stent lengths) than those obtained using QCA.

Measurements of Lumen Areas and Diameters of Proximal and Middle Coronary Artery Segments in Subjects Without Coronary Atherosclerosis

There are plenty of data on morphology and lumen dimensions of diseased coronary arteries. However, information on normal coronary vessel anatomy is scarce. We provided computed tomography angiography-derived reference values of lumen dimensions in proximal and middle coronary segments in a healthy population with respect to gender and vessel dominance. Consecutive 2,849 computed tomography angiography examinations were reviewed to identify 201 subjects (77 men, patient age 50 ± 13 years) whose coronary arteries were free from any sign of atherosclerosis (calcium score 0, no detectable plaque). For all proximal and middle coronary segments, lumen areas (LAs) and lumen diameters were measured. Coronary vessel segmentation and dominance pattern were defined using the Syntax Score. Normal values of LAs and lumen diameters were significantly smaller for women compared with men except for the proximal right coronary artery and the left main coronary artery (LMCA) (20.2 ± 6.6 mm2 vs 23.0 ± 6.1 mm2, p = 0.0003, and 5.0 ± 0.8 mm vs 5.4 ± 0.7 mm, p = 0.0001). The lower limit of normal for the LMCA (defined as mean LA - 2 standard deviations) equaled 7.0 and 10.8 mm2 for women and men, respectively. Subjects with left (vs right) coronary dominance had significantly larger areas and diameters of the LMCA (26.2 ± 9.2 mm2 vs 20.7 ± 6.0 mm2, p = 0.0017, and 5.7 ± 1.0 mm vs 5.1 ± 0.7 mm, p = 0.0017, respectively) and proximal left circumflex (13.8 ± 2.7 mm2 vs 10.4 ± 3.8 mm2, p = 0.0001, and 4.2 ± 0.4 mm vs 3.6 ± 0.7 mm, p = 0.0001, respectively) and smaller areas and diameters of the proximal right coronary artery (7.1 ± 2.0 mm2 vs 13.3 ± 3.6 mm2, p <0.0001, and 3.0 ± 0.4 mm vs 4.1 ± 0.6 mm, p <0.0001, respectively). In conclusion, gender and coronary artery dominance pattern significantly impact normal LAs and dimensions in subjects without coronary atherosclerosis.

Comparison of Plaque Burden and Vessel Remodeling in Obstructive Saphenous Vein Graft Lesions as Assessed by Intravascular Ultrasound and Dual-source Computed Tomography.

Purpose: The aim of our study was to compare plaque burden and vessel remodeling of obstructive saphenous vein graft (SVG) lesions as assessed by dual-source computed tomography (DSCT) and intravascular ultrasound (IVUS). Materials and Methods: Preintervention DSCT examination and IVUS were performed in consecutive patients before percutaneous treatment of the SVG lesion. SVG vessel and lumen areas were measured with use of DSCT and IVUS at the minimal lumen area (MLA) site and at proximal and distal reference sites. Plaque burden was defined as the ratio of plaque and vessel area. Remodeling index was defined as the ratio of the SVG area at the MLA site to the mean reference SVG area. Results: Twenty-four obstructive SVG lesions were imaged with DSCT and IVUS before stent implantation in 24 patients. The SVG cross-sectional area at the MLA site measured by IVUS and DSCT was similar (17.0±4.5 vs. 17.3±5.3 mm2, P=0.6) and well correlated (R=0.77, P<0.001). Similarly, plaque burden and remodeling index assessments did not differ significantly between the 2 imaging modalities (79.0%±4.0% vs. 81.0%±8.0%, P=0.18, and 1.09±0.22 vs. 1.07±0.32, P=0.7 for IVUS vs. DSCT for plaque burden and remodeling, respectively). The correlation between IVUS-assessed and DSCT-assessed plaque burden and remodeling index was moderate to good (R=0.55, P=0.01 and R=0.77, P<0.001, respectively, for plaque burden and remodeling index). Conclusions: There is moderate to good correlation between DSCT and IVUS in the assessment of vessel remodeling and plaque burden in obstructive SVG lesions. Noninvasive assessment and monitoring of SVG disease is feasible using DSCT.

Zależność efektu brachyterapii wewnątrznaczyniowej od wielkości dawki

Streszczenie Nawrot zweznia po interwencyjnym leczeniu choroby wiencowej jest najpowazniejszym powodem niepowodzen w kardiologii inwazyjnej. Leczenie zmian nawrotowych związane jest ze zwiekszonym ryzykiem powtornej restenozy. Uznaną metodą o udokumentowanej skuteczności w zmniejszaniu ryzyka kolejnego nawrotu zwezenia jest brachyterapia wewnątrzwiencowa. Źrodlo promieniowania beta lub gamma wprowadzane zostaje do światla naczynia po zabiegu balonowej angioplastyki zmiany restenotycznej. Za obszar (target) dla promieniowania uwazana jest struktura przydanki, ktora jest Źrodlem komorek odpowiedzialnych za rozplem tkanki restenotycznej – neointimy. W celu planowania dawki promieniowania stosowane są dwie metody dozymetrii:“dozymetria standardowa” i “dozymetria indywidualna”. Istnieją kontrowersje dotyczące wplywu wielkości dawki promieniowania na skutecznośc brachyterapii wewnątrzwiencowej. Celem pracy jest przedstawienie aktualnego stanu wiedzy dotyczącego zalezności pomiedzy dawką promieniowania a odleglym efektem brachyterapii wewnątrzwiencowej. Szczegolną uwage zwrocono na znaczenie analizy tzw. histogramow dawka – objetośc (dose volume histograms) w kontekście brachyterapii wewnątrzwiencowej. Ponadto przedstawiono opis dawkozaleznych niepoządanych efektow ubocznych brachyterapii nawrotowych zwezn w tetnicach wiencowych.