Hintergrund und Fragestellung Um den Zeitpunkt des Beginns der Datenakquisition bei der CT-Koronarangiographie festzulegen, bietet die Methode des Bolus-Trackings eine weit verbreitete Möglichkeit. Hierfür muss eine sogenannte Region of Interest (ROI) festgelegt werden, in der die Kontrastmittelanflutung gemessen wird. Bisher wurden die Auswirkungen unterschiedlicher Positionierungen dieser ROI auf die Bildqualität der Koronararterien (Hauptstamm der linken Koro-nararterie: LM; rechte Koronararterie: RCA) noch nicht systematisch untersucht. Zwei häufig verwendete Positionen sind der linke Herzvorhof (LV) und die Aorta ascendens (AA). Diese Positionierungen sollten in dieser Studie verglichen werden. Auch bei der Triple-Rule-Out-CT-Angiographie (TRO-CTA), in der zusätzlich zu den Koronararterien auch die Pulmonalarterien sowie die thorakale Aorta beurteilt werden sollen, kommt das Bolus-Tracking zur Anwendung. Die ROI wird hierbei meist im linken Herzvorhof positioniert. Da bisher nicht gezeigt wurde, ob die Pulmonalarterien (rechte Pulmonalarterie: RPA; linke Pulmonalarterie: LPA) dadurch tatsächlich in besserer Qualität dargestellt werden, sollte auch diese Frage in der Studie beantwortet werden. Methode Alle Patienten der vorliegenden monozentrischen, retrospektiven Studie erhielten eine CT-Koronarangiographie im Step-and-Shoot-Modus zum Ausschluss einer koronaren Herzkrankheit bei intermediärem Risiko. Mittels Propensity-Score-Matching wurden insgesamt 192 Patienten für die Studie ausgewählt: je 96 mit Positionierung der ROI im linken Vorhof bzw. in der Aorta ascendens (122 männliche und 70 weibliche Patienten, Alter 21 bis 87 Jahre, Durchschnittsalter 61 Jahre). Um möglichst ähnliche Patientencharakteristika in beiden Gruppen zu erreichen, wurden beim Propensity-Score-Matching folgende Faktoren berücksichtigt: Geschlecht, Körpergröße, Körpergewicht und Herzfrequenz. Für die Beurteilung der Bildqualität wurden sowohl ein quantitativer als auch ein qualitativer Score verwendet. Bei der quantitativen Analyse wurden die Signalintensitäten sowie deren Standardabweichungen in den zu beurteilenden Strukturen gemessen und daraus die Signal-Rausch-Verhältnisse (SNR) errechnet. Die qualitative Auswertung wurde von zwei Fachärzten für Radiologie mit 10 bzw. 6 Jahren Erfahrung in der CT-Koronarangiographie unabhängig voneinander mit Hilfe einer 5-Punkte-Likert-Skala durchgeführt. So wurde zum einen die Qualität der Darstellung der Koronararterien verglichen, zum anderen die der Pulmonalarterien. Für die statistische Auswertung wurde der Wilcoxon-Test verwendet, um die quantitativen sowie qualitativen Scores beider Patientengruppen miteinander zu vergleichen. Außerdem wurde bezüglich der qualitativen Analyse die Interrater-Reliabilität mittels gewichtetem Cohens Kappa (κ) bestimmt. Zusätzlich wurde die Strahlenbelastung beider Gruppen durch die Betrachtung der Dosis-Längen-Produkte sowie die Berechnung der effektiven Dosen verglichen. Ergebnisse Bezüglich der Koronararterien fanden sich sowohl beim Vergleich der quantitativen (SNR AA 14.92 vs. 15.46; p = 0.619 | SNR LM 19.80 vs. 20.30; p = 0.661 | SNR RCA 24.34 vs. 24.30; p = 0.767) als auch der qualitativen Scores (4.25 vs. 4.29; p = 0.672) keine signifikanten Unterschiede in beiden Gruppen. Für die Darstellung der Pulmonalarterien hat die Position der ROI allerdings eine entscheidende Bedeutung. Bei einer Positionierung im linken Vorhof ergeben sich signifikant höhere quantitative (SNR RPA 8.70 vs. 5.89; p < 0.001 | SNR LPA 9.06 vs. 6.25; p < 0.001) und auch qualitative Scores (3.97 vs. 2.24; p < 0.001) als bei einer Positionierung in der Aorta ascendens. Bezüglich der Interrater-Reliabilität konnte in dieser Studie eine beachtliche Konkordanz bei der Analyse der Koronararterien (κ = 0.654) bzw. eine nahezu vollkommene Konkordanz bei der Analyse der Pulmonalarterien (κ = 0.846) festgestellt werden. Die Strahlenbelastung war in beiden Gruppen nahezu identisch (4.13 mSv vs. 4.13 mSv; p = 0.501). Schlussfolgerung Für CT-Angiographien mit ausschließlich koronarer Indikation bedeutet dieses Ergebnis, dass die Positionierung der ROI für das Bolus-Tracking in der Aorta ascendens bzw. im linken Herzvorhof zu gleichwertigen Ergebnissen bezüglich der Bildqualität führen und somit die aktuell von vielen Untersuchern bevorzugte Positionierung der ROI in der Aorta ascendens weiterhin angewendet werden kann. Außerdem wurde in dieser Studie nachgewiesen, dass eine Positionierung der ROI im linken Herzvorhof zu einer besseren Beurteilbarkeit der Pulmonalarterien führt und deshalb bei der TRO-CTA angewendet werden sollte. Das Ergebnis zeigt aber auch, dass diese bei der TRO-CTA übliche Positionierung im linken Herzvorhof die Abbildung der Koronararterien nicht beeinträchtigt und der Einsatzbereich der TRO-CTA somit weiter ausgedehnt werden kann. / Background, aims and objectives The bolus tracking technique is widely used for choosing the optimal starting point of data acquisition in coronary computed tomography angiography (CCTA) scans. It utilizes repeated scans at a predefined position in order to determine the concentration of contrast media in a region of interest (ROI). The scan starts automatically when a trigger threshold is reached. The effect by different ROI positioning on image quality in CCTA has not been systematically evaluated yet. In CCTA, the ROI may be positioned in the left atrium (LV) or the ascending aorta (AA). In triple-rule-out-CTA (TRO-CTA), which allows for the evaluation of the pulmonary arteries and the thoracic aorta in addition to the coronary arteries, the ROI is mostly positioned in the left atrium. This choice of ROI positioning is empirical and its effect on the contrast filling of the pulmonary arteries has not been studied systematically. In the current study we evaluated the effect of ROI positioning on image quality of the coronary arteries (left main coronary artery: LM; right coronary artery: RCA) and the pulmonary arteries (right pulmonary artery: RPA; left pulmonary artery: LPA), respectively. Method In the current monocentric retrospective study all patients underwent CCTA by step-and-shoot mode to rule out coronary artery disease at intermediate risk. We compared two groups of patients with ROI in the left atrium or the ascending aorta. Each group contained 96 patients, so overall 192 patients were included (122 male, 70 female, age 21 to 87 years, 61 years on average). To select pairs of patients with similar characteristics, propensity score matching was used. Matching criteria were height, body weight, sex and heart rate. To evaluate the image quality, we used quantitative and qualitative scores. Signal-to-noise ratio (SNR), defined as the quotient of the mean signal intensity and the standard deviation of signal intensity, represented the quantitative score. For generating the qualitative score, overall image quality was assessed independently by two radiologists with ten and six years of experience with CCTA, respectively, using a five point Likert scale. This way, we compared the quality of the depiction of the coronary arteries on the one hand and of the pulmonary arteries on the other hand. For statistical evaluation the Wilcoxon test was used to compare the quantitative and qualitative scores of the two groups. Regarding the qualitative analysis, interrater agreement was evaluated using weighted Cohens kappa. Furthermore the radiation exposure was compared by viewing the dose-length products provided by the scanner and calculating the effective doses from these. Results In terms of the coronary arteries, there was no significant difference between both groups regarding quantitative (SNR AA 14.92 vs. 15.46; p = 0.619 | SNR LM 19.80 vs. 20.30; p = 0.661 | SNR RCA 24.34 vs. 24.30; p = 0.767) or qualitative scores (4.25 vs. 4.29; p = 0.672), respectively. In terms of the pulmonary arteries, we can see significant higher quantitative (SNR RPA 8.70 vs. 5.89; p < 0.001 | SNR LPA 9.06 vs. 6.25; p < 0.001) and qualitative scores (3.97 vs. 2.24; p < 0.001) for bolus tracking positioning in the left atrium than for bolus tracking positioning in the ascending aorta. The calculation of the interrater reliability showed substantial agreement for the analysis of the coronary arteries (κ = 0.654) and almost perfect agreement for the analysis of the pulmonary arteries (κ = 0.846). The radiation exposure was almost identical in both groups of patients (4.13 mSv vs. 4.13 mSv; p = 0.501). Conclusion Bolus tracking positioning in the left atrium or the ascending aorta causes equivalent image quality of the coronary arteries, so that the current mostly preferred position for the exclusively consideration of the coronary arteries in the ascending aorta can be maintained. Positioning in the left atrium causes a significant higher image quality of the pulmonary arteries, therefore it should be used for TRO-CTA. In addition, the study shows that this for TRO-CTA mostly used position in the left atrium does not adversely affect depiction of the coronary arteries, if compared to conventional bolus tracking positioning in the ascending aorta. This implies that despite the improved depiction of the pulmonary arteries and the aorta in TRO-CTA, the depiction of the coronary arteries is not restricted. Consequently these results are a further argument for an extension of the indication for TRO-CTA in place of conventional CCTA in patients with acute thoracic pain.

Objetivos: O objetivo deste estudo é analisar a perviedade da artéria torácica interna direita (ATID) pediculada, anteroaórtica em anastomose para a região anterior do coração na cirurgia de revascularização do miocárdio (RM), em relação à artéria torácica interna esquerda (ATIE). Métodos: No período de dezembro de 2008 a dezembro de 2011, 100 pacientes foram selecionados para serem submetidos a cirurgia de RM sem circulação extracorpórea (CEC), de forma prospectiva. Eles foram agrupados em Grupo 1 (G-1) e Grupo 2 (G-2), cada um com 50 pacientes, com randomização por computador e conhecimento da técnica no início da cirurgia. No G-1, os pacientes receberam ATIE para a região anterior do coração e complementação da RM com a ATID livre para ramos da circunflexa (CX) e outros enxertos arteriais ou venosos para a coronária direita (CD) e/ou ramos. Os pacientes do G-2 receberam ATID pediculada para a região anterior do coração e complementação da RM com ATIE, pediculada, para ramos da CX e outros enxertos arteriais ou venosos para a CD e/ou ramos. A perviedade das artérias torácicas internas direita e esquerda foi avaliada através de angiotomografia coronária multislice, 64 canais, no 6º mês de pós-operatório. Resultados: Os dois grupos eram semelhantes quanto aos dados clínicos de pré-operatório, como exemplo: diabetes mellitus, hipertensão arterial sistêmica, obesidade. Os dois grupos apresentaram predominância do sexo masculino com 75,6% e 88% nos grupos 1 e 2, respectivamente. Cinco pacientes migraram do G-1 para o G-2 em virtude de doença ateromatosa na aorta ascendente e um deles foi excluído por ter que utilizar enxerto composto. A média de anastomoses distais no G-1 foi de 3,48 (DP=0,72), e no G-2 foi de 3,20 (DP=0,76). Não ocorreu mediastinite em nenhum paciente. Uma paciente do G-1 apresentou osteomielite, e necessitou de intervenção cirúrgica. Dois pacientes do G-1 foram submetidos a reoperação por sangramento. Os resultados das angiotomografias coronarianas com 96 pacientes re-estudados mostram que todas as ATIs, fosse a direita ou a esquerda, utilizadas pediculadas para a região anterior do coração encontravam-se sem oclusões ou estenoses, configurando 100% de perviedade. No G-1, um enxerto livre da ATID para ramos da CX apresentava oclusão total, em dois pacientes havia estenose leve, em um deles havia estenose moderada na anastomose proximal na aorta ascendente e outro apresentava diminuição de calibre na sua porção distal. Em três pacientes o enxerto de segmento de veia safena para ramos da CD se encontravam ocluídos. No G-2, dois pacientes apresentavam oclusão total na ATIE pediculada para ramos da CX, e outro apresentava estenose moderada na porção distal da ATIE utilizada sequencial para dois ramos marginais. Em dois pacientes o enxerto de segmento de veia safena para ramos da CD se encontravam ocluídos. Não houve óbitos em nenhum dos grupos. Conclusão: A cirurgia de RM com utilização da ATID pediculada, anterógrada para o RIA, apresenta resultado semelhante ao da ATIE utilizada para essa mesma coronária. / Objective: To analyze the patency of the pedicled, anteroaortic, right internal mammary artery (RIMA) anastomosed to the left anterior descending (LAD) and branches in coronary artery bypass graft surgery (CABG), in comparison with the left internal mammary artery (LIMA). Methods: From December 2008 to December 2011, 100 patients were selected to undergo a prospective off-pump coronary artery bypass graft surgery and were randomly divided by computer into Group 1 (G-1) and Group 2 (G-2), so that the technique was known at the beginning of the surgery. In each group, with 50 patients, the patency of both right and left internal mammary arteries, which were used pedicled to the LAD, was comparatively studied through coronary computed tomography angiography. G-1 had 50 patients who received the LIMA to the LAD or LAD/diagonal (sequential) and had the CABG complemented with the free RIMA to circumflex branches and other arterial or venous grafts to the right coronary artery (RCA) and/or branches. G-2 had 50 patients who received the pedicled RIMA to the LAD or LAD/diagonal (sequential) and had the CABG complemented with the pedicled LIMA to circumflex branches and other arterial or venous grafts to the RCA and/or branches. Results: Both groups were similar in pre-operative clinical data, such as: diabetes mellitus, systemic arterial hypertension, obesity. Also, there was predominance of males in both groups, with 75,6% and 88% in Groups 1 and 2 respectively. Five patients were switched from G-1 to G-2 owing to atheromatous disease in the ascending aorta, and one of them was dropped for having to use composite graft. The average of distal anastomosis in G-1 was 3,48 (standard deviation (SD=0,72) and in G-2 was 3,20 (SD=0,76). Mediastinitis didn\'t occur in any patient. A patient from G-1 had osteomyelitis that required surgical intervention. Two patients from G-1 underwent reoperation because of bleeding. The 64-slice coronary computed tomography angiography was performed in the 6th postoperative month; 96 patients have been re-studied so far and all pedicled IMAs to the LAD were patent. In G-1 a free RIMA graft to the circumflex branches presented total occlusion, another two had a discreet stenosis and in one moderate at the proximal anastomosis and one more had a string signal at the distal portion. In G-2 two patients had total occlusion of the pedicled LIMA to circumflex artery branches, and another one presented moderate stenosis at its distal portion. In two patients the saphenous vein graft to the RCA branches were occluded. There were no deaths in any of the groups. Conclusion: The CABG surgery using the pedicled, anteroaortic RIMA to the LAD has a similar outcome to that of the LIMA used for this same coronary.

Objetivos: O objetivo deste estudo é analisar a perviedade da artéria torácica interna direita (ATID) pediculada, anteroaórtica em anastomose para a região anterior do coração na cirurgia de revascularização do miocárdio (RM), em relação à artéria torácica interna esquerda (ATIE). Métodos: No período de dezembro de 2008 a dezembro de 2011, 100 pacientes foram selecionados para serem submetidos a cirurgia de RM sem circulação extracorpórea (CEC), de forma prospectiva. Eles foram agrupados em Grupo 1 (G-1) e Grupo 2 (G-2), cada um com 50 pacientes, com randomização por computador e conhecimento da técnica no início da cirurgia. No G-1, os pacientes receberam ATIE para a região anterior do coração e complementação da RM com a ATID livre para ramos da circunflexa (CX) e outros enxertos arteriais ou venosos para a coronária direita (CD) e/ou ramos. Os pacientes do G-2 receberam ATID pediculada para a região anterior do coração e complementação da RM com ATIE, pediculada, para ramos da CX e outros enxertos arteriais ou venosos para a CD e/ou ramos. A perviedade das artérias torácicas internas direita e esquerda foi avaliada através de angiotomografia coronária multislice, 64 canais, no 6º mês de pós-operatório. Resultados: Os dois grupos eram semelhantes quanto aos dados clínicos de pré-operatório, como exemplo: diabetes mellitus, hipertensão arterial sistêmica, obesidade. Os dois grupos apresentaram predominância do sexo masculino com 75,6% e 88% nos grupos 1 e 2, respectivamente. Cinco pacientes migraram do G-1 para o G-2 em virtude de doença ateromatosa na aorta ascendente e um deles foi excluído por ter que utilizar enxerto composto. A média de anastomoses distais no G-1 foi de 3,48 (DP=0,72), e no G-2 foi de 3,20 (DP=0,76). Não ocorreu mediastinite em nenhum paciente. Uma paciente do G-1 apresentou osteomielite, e necessitou de intervenção cirúrgica. Dois pacientes do G-1 foram submetidos a reoperação por sangramento. Os resultados das angiotomografias coronarianas com 96 pacientes re-estudados mostram que todas as ATIs, fosse a direita ou a esquerda, utilizadas pediculadas para a região anterior do coração encontravam-se sem oclusões ou estenoses, configurando 100% de perviedade. No G-1, um enxerto livre da ATID para ramos da CX apresentava oclusão total, em dois pacientes havia estenose leve, em um deles havia estenose moderada na anastomose proximal na aorta ascendente e outro apresentava diminuição de calibre na sua porção distal. Em três pacientes o enxerto de segmento de veia safena para ramos da CD se encontravam ocluídos. No G-2, dois pacientes apresentavam oclusão total na ATIE pediculada para ramos da CX, e outro apresentava estenose moderada na porção distal da ATIE utilizada sequencial para dois ramos marginais. Em dois pacientes o enxerto de segmento de veia safena para ramos da CD se encontravam ocluídos. Não houve óbitos em nenhum dos grupos. Conclusão: A cirurgia de RM com utilização da ATID pediculada, anterógrada para o RIA, apresenta resultado semelhante ao da ATIE utilizada para essa mesma coronária. / Objective: To analyze the patency of the pedicled, anteroaortic, right internal mammary artery (RIMA) anastomosed to the left anterior descending (LAD) and branches in coronary artery bypass graft surgery (CABG), in comparison with the left internal mammary artery (LIMA). Methods: From December 2008 to December 2011, 100 patients were selected to undergo a prospective off-pump coronary artery bypass graft surgery and were randomly divided by computer into Group 1 (G-1) and Group 2 (G-2), so that the technique was known at the beginning of the surgery. In each group, with 50 patients, the patency of both right and left internal mammary arteries, which were used pedicled to the LAD, was comparatively studied through coronary computed tomography angiography. G-1 had 50 patients who received the LIMA to the LAD or LAD/diagonal (sequential) and had the CABG complemented with the free RIMA to circumflex branches and other arterial or venous grafts to the right coronary artery (RCA) and/or branches. G-2 had 50 patients who received the pedicled RIMA to the LAD or LAD/diagonal (sequential) and had the CABG complemented with the pedicled LIMA to circumflex branches and other arterial or venous grafts to the RCA and/or branches. Results: Both groups were similar in pre-operative clinical data, such as: diabetes mellitus, systemic arterial hypertension, obesity. Also, there was predominance of males in both groups, with 75,6% and 88% in Groups 1 and 2 respectively. Five patients were switched from G-1 to G-2 owing to atheromatous disease in the ascending aorta, and one of them was dropped for having to use composite graft. The average of distal anastomosis in G-1 was 3,48 (standard deviation (SD=0,72) and in G-2 was 3,20 (SD=0,76). Mediastinitis didn\'t occur in any patient. A patient from G-1 had osteomyelitis that required surgical intervention. Two patients from G-1 underwent reoperation because of bleeding. The 64-slice coronary computed tomography angiography was performed in the 6th postoperative month; 96 patients have been re-studied so far and all pedicled IMAs to the LAD were patent. In G-1 a free RIMA graft to the circumflex branches presented total occlusion, another two had a discreet stenosis and in one moderate at the proximal anastomosis and one more had a string signal at the distal portion. In G-2 two patients had total occlusion of the pedicled LIMA to circumflex artery branches, and another one presented moderate stenosis at its distal portion. In two patients the saphenous vein graft to the RCA branches were occluded. There were no deaths in any of the groups. Conclusion: The CABG surgery using the pedicled, anteroaortic RIMA to the LAD has a similar outcome to that of the LIMA used for this same coronary.

Leaflet replacement in aortic valve repair (AVr) is associated with increased long-term repair failure. Hemodynamic performance and mechanical stress levels were investigated after porcine AVr with 5 types of clinically relevant replacement materials to ascertain which material(s) would be best suited for repair. Porcine aortic roots with intact aortic valves were placed in a left-heart simulator mounted with a high-speed camera for baseline valve assessment. Then, the non-coronary leaflet was excised and replaced with autologous porcine pericardium (APP), glutaraldehyde-fixed bovine pericardial patch (BPP; Synovis™), extracellular matrix scaffold (CorMatrix™), or collagen-impregnated Dacron (HEMASHIELD™). Hemodynamic parameters were measured over a range of cardiac outputs (2.5–6.5L/min) post-repair. Material properties of the above materials along with St. Jude Medical™ Pericardial Patch with EnCapTM Technology (SJM) were determined using pressurization experiments. Finite element models of the aortic valve and root complex were then constructed to verify the hemodynamic characteristics and determine leaflet stress levels. This study demonstrates that APP and SJM have the closest profiles to normal aortic valves; therefore, use of either replacement material may be best suited. Increased stresses found in BPP, HEMASHIELD™, and CorMatrix™ groups may be associated with late repair failure.

Leaflet replacement in aortic valve repair (AVr) is associated with increased long-term repair failure. Hemodynamic performance and mechanical stress levels were investigated after porcine AVr with 5 types of clinically relevant replacement materials to ascertain which material(s) would be best suited for repair. Porcine aortic roots with intact aortic valves were placed in a left-heart simulator mounted with a high-speed camera for baseline valve assessment. Then, the non-coronary leaflet was excised and replaced with autologous porcine pericardium (APP), glutaraldehyde-fixed bovine pericardial patch (BPP; Synovis™), extracellular matrix scaffold (CorMatrix™), or collagen-impregnated Dacron (HEMASHIELD™). Hemodynamic parameters were measured over a range of cardiac outputs (2.5–6.5L/min) post-repair. Material properties of the above materials along with St. Jude Medical™ Pericardial Patch with EnCapTM Technology (SJM) were determined using pressurization experiments. Finite element models of the aortic valve and root complex were then constructed to verify the hemodynamic characteristics and determine leaflet stress levels. This study demonstrates that APP and SJM have the closest profiles to normal aortic valves; therefore, use of either replacement material may be best suited. Increased stresses found in BPP, HEMASHIELD™, and CorMatrix™ groups may be associated with late repair failure.