Lukas Lehmkuhl

Image quality and radiation exposure with prospectively ECG-triggered axial scanning for coronary CT angiography: The multicenter, multivendor, randomized PROTECTION-III Study

OBJECTIVES The purpose of this study was to evaluate image quality and radiation dose using a prospectively electrocardiogram (ECG)-triggered axial scan protocol compared with standard retrospective ECG-gated helical scanning for coronary computed tomography angiography. BACKGROUND Concerns have been raised regarding radiation exposure during coronary computed tomography angiography. Although the use of prospectively ECG-triggered axial scan protocols may effectively lower radiation dose compared with helical scanning, it is unknown whether image quality is maintained in a clinical setting. METHODS In a prospective, multicenter, multivendor trial, 400 patients with low and stable heart rates were randomized to either an axial or a helical coronary computed tomography angiography scan protocol. The primary endpoint was to demonstrate noninferiority in image quality with the axial scan protocol, which was assessed on a 4-point scale (1 = nondiagnostic, 4 = excellent image quality). Secondary endpoints included radiation dose and the rate of downstream testing during 30-day follow-up. RESULTS Image quality in patients scanned with the axial scan protocol (score 3.36 ± 0.59) was not inferior compared with helical scan protocols (3.37 ± 0.59) (p for noninferiority <0.004). Axial scanning was associated with a 69% reduction in radiation exposure (dose-length product [estimated effective dose] 252 ± 147 mGy · cm [3.5 ± 2.1 mSv] vs. 802 ± 419 mGy · cm [11.2 ± 5.9 mSv] for axial vs. helical scan protocols, p < 0.001). The rate of downstream testing did not differ (13.8% vs. 15.9% for axial vs. helical scan protocols, p = 0.555). CONCLUSIONS In patients with stable and low heart rates, the prospectively ECG-triggered axial scan protocol maintained image quality but reduced radiation exposure by 69% compared with helical scanning. Axial computed tomography data acquisition should be strongly recommended in suitable patients to avoid unnecessarily high radiation exposure.

Aortic valve calcium scoring is a predictor of significant paravalvular aortic insufficiency in transapical-aortic valve implantation‡

OBJECTIVE Transapical-aortic valve implantation (TA-AVI) has evolved as routine for selected high-risk patients. However, paravalvular leaks >1+ remain an unsolved issue using current generations of transcatheter valve devices. The purpose of this study was to investigate the impact of native aortic valve calcification on paravalvular leaks and outcomes using the Edwards SAPIEN™ prosthesis. METHODS One hundred and twenty consecutive patients (out of 307 TA-AVIs) with preoperative computed tomography aged 82.6 ± 6.2 years, 75.0% female were included. Implanted prosthetic valve sizes were 23 mm (n = 31) and 26 mm (n = 89), respectively. Mean logistic European System for Cardiac Operative Risk Evaluation-Score was 30.1 ± 15.5% and mean Society of Thoracic Surgeons-Score was 12.8 ± 7.9%. Electrocardiographic (ECG)-gated cardiac computed tomography allowed to quantify the amount of calcification of aortic valve leaflets using a scoring analogous to the Agatston calcium scoring of coronary arteries [Aortic Valve Calcium Scoring (AVCS)]. Paravalvular leaks were assessed intraoperatively by echocardiography and root angiography. RESULTS All valves were implanted successfully. The mean AVCS in patients without paravalvular leaks (n = 66) was 2704 ± 1510; with mild paravalvular leaks (n = 31) was 3804 ± 2739 (P = 0.05); and with moderate paravalvular leaks (n = 4) was 7387 ± 1044 (P = 0.002). There was a significant association between the AVCS and paravalvular leaks [odds ratio (OR; per AVCS of 1000), 11.38; 95% confidence interval (CI) 2.33-55.53; P = 0.001)] and a trend towards a higher incidence of new pacemaker implantation (OR 1.27; 95% CI 0.85-1.89; P = 0.26). No association was found to 30-day mortality, major cardiac events and stroke rate (OR 1.05; 95% CI 0.84-1.32; P = 0.68; OR 0.92; 95% CI 0.68-1.25; P = 0.57 and OR 0.90; 95% CI 0.41-1.96; P = 0.79, respectively). Overall 30-day mortality was 14.2%. CONCLUSION Severe native valve calcifications are predictive for postoperative relevant paravalvular leak. AVCS prior to TA-AVI might serve as an additional tool to reconsider the TAVI indication to reduce the risk of paravalvular leaks especially in so-called operable patients.

Effect of a Cerebral Protection Device on Brain Lesions Following Transcatheter Aortic Valve Implantation in Patients With Severe Aortic Stenosis: The CLEAN-TAVI Randomized Clinical Trial

IMPORTANCE Stroke remains a major predictor of mortality after transcatheter aortic valve implantation (TAVI). Cerebral protection devices might reduce brain injury as determined by diffusion-weighted magnetic resonance imaging (DWMRI). OBJECTIVE To determine the effect of a cerebral protection device on the number and volume of cerebral lesions in patients undergoing TAVI. DESIGN, SETTING, AND PARTICIPANTS Investigator-initiated, single center, blinded, randomized clinical trial in higher-risk patients with severe aortic stenosis undergoing TAVI at the University of Leipzig Heart Center. Brain MRI was performed at baseline, 2 days, and 7 days after TAVI. Between April 2013 and June 2014, patients were randomly assigned to undergo TAVI with a cerebral protection device (filter group) or without a cerebral protection device (control group). The last 1-month follow-up occurred in July 2014. INTERVENTIONS TAVI with or without a cerebral protection device (filter system). MAIN OUTCOMES AND MEASURES The primary end point was the numerical difference in new positive postprocedure DWMRI brain lesions at 2 days after TAVI in potentially protected territories. The first hierarchical secondary outcome was the difference in volume of new lesions after TAVI in potentially protected territories. RESULTS Among the 100 enrolled patients, mean (SD) age was 80.0 (5.1) years in the filter group (n = 50) and 79.1 (4.1) years in the control group (n = 50), and the mean (SD) procedural risk scores (logistic EuroScores) were 16.4% (10.0%) in the filter group and 14.5% (8.7%) in the control group. For the primary end point, the number of new lesions was lower in the filter group, 4.00 (interquartile range [IQR], 3.00-7.25) vs 10.00 (IQR, 6.75-17.00) in the control group (difference, 5.00 [IQR, 2.00-8.00]; P < .001). For the first hierarchical secondary end point, new lesion volume after TAVI was lower in the filter group (242 mm3 [95% CI, 159-353]) vs in the control group (527 mm3 [95% CI, 364-830]) (difference, 234 mm3 [95% CI, 91-406]; P = .001). Considering adverse events, 1 patient in the control group died prior to the 30-day visit. Life-threatening hemorrhages occurred in 1 patient in the filter group and 1 in the control group. Major vascular complications occurred in 5 patients in the filter group and 6 patients in the control group. One patient in the filter group and 5 in the control group had acute kidney injury, and 3 patients in the filter group had a thoracotomy. CONCLUSIONS AND RELEVANCE Among patients with severe aortic stenosis undergoing TAVI, the use of a cerebral protection device reduced the frequency of ischemic cerebral lesions in potentially protected regions. Larger studies are needed to assess the effect of cerebral protection device use on neurological and cognitive function after TAVI and to devise methods that will provide more complete coverage of the brain to prevent new lesions. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01833052.

Visceral Arterial Compromise During Intra-Aortic Balloon Counterpulsation Therapy

Background— Intraaortic balloon pump (IABP) therapy is a widely used method of circulatory support. Based on frequent findings of balloon malposition with visceral arterial compromise on computerized tomographic (CT) imaging studies, we conducted a systematic review of cardiac surgical IABP patients with available CT scans to determine reasons, incidence, and clinical relevance of malposition. Methods and Results— From January 2007 to March 2009, a total of 621 of 7756 cardiac surgical patients (8.0%) received perioperative IABP support, of whom 63 (10.1%) received a thoracoabdominal CT scan during IABP support. Proximal and distal balloon positions were analyzed. The anatomic distance from the left subclavian artery to celiac trunk and aortic transverse diameter were measured in all patients and compared with implanted balloon dimensions. Mean age was 67.1±11.9 years; 33.3% were female, and height was 169±9 cm. Based on radiography, proximal balloon position was correct in 96.8% but only appropriate in 38.1% based on CT. In 61 of 63 patients, compromise of at least 1 visceral artery was found: celiac trunk, 96.8%; superior mesenteric artery, 87.3%; and renal arteries, 66.7%. Left subclavian artery to celiac trunk distance was 241±23 mm, and balloon length was 248±17 mm and corresponded to an anatomic to balloon length mismatch in 68.2%. Spinal deformations were found in 42.9%. Laparotomy for mesenteric ischemia was required in 23.8%. Hospital mortality rate was 60.3%. Conclusions— IABP malposition was commonly identified by CT. Reasons included incorrect proximal balloon position as well as an anatomic-to-balloon length mismatch. Thus, shorter than recommended balloon sizes and better positioning strategies had to be considered.

Right ventricular injury in ST-elevation myocardial infarction: risk stratification by visualization of wall motion, edema, and delayed-enhancement cardiac magnetic resonance.

Background— Patients with right ventricular injury (RVI) complicating ST-elevation myocardial infarction (STEMI) have impaired prognosis, but it is unclear which patients are at risk of developing RVI. Cardiac magnetic resonance can identify these patients and might add important information on risk stratification, prognosis, and treatment. Aims were to determine the predictors and the prognostic significance of RVI assessed by wall motion abnormalities, edema, myocardial salvage index, and delayed enhancement in acute reperfused STEMI. Methods and Results— We studied 450 patients 1–4 days after primary angioplasty in STEMI. T2-weighted and delayed-enhancement cardiac magnetic resonance was used for visualizing edema and scar to calculate myocardial salvage index. Cine-imaging was performed to assess wall motion abnormalities, which, in combination with edema, were considered diagnostic for RVI. Patients with RVI were compared with matched patients with isolated left ventricular infarction. The primary end point was the occurrence of a major adverse cardiac event: a composite of death, reinfarction, and congestive heart failure after a median follow-up period of 20.9 months. RVI was present in 69 patients, and 41 of 69 showed myocardial necrosis. In a multivariable stepwise forward logistic regression analysis, a high RV myocardial mass (odds ratio, 2.06; 95% confidence interval, 1.18–3.58; P =0.012) and a low Thrombolysis In Myocardial Infarction flow before angioplasty (odds ratio, 0.50; 95% confidence interval, 0.32–0.76; P =0.011) were associated with RVI. Cox regression analysis revealed RVI as the most statistically significant predictor of time to major adverse cardiac events (hazard-ratio, 3.36; 95% confidence interval, 1.99–5.66; P <0.001). Conclusions— RVI detected by cardiac magnetic resonance is a strong and independent predictor of clinical outcome after acute reperfused STEMI. Clinical Trial Registration— URL: . Unique identifier: [NCT01359306][1]. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01359306&atom=%2Fcirccvim%2F5%2F1%2F60.atomBackground— Patients with right ventricular injury (RVI) complicating ST-elevation myocardial infarction (STEMI) have impaired prognosis, but it is unclear which patients are at risk of developing RVI. Cardiac magnetic resonance can identify these patients and might add important information on risk stratification, prognosis, and treatment. Aims were to determine the predictors and the prognostic significance of RVI assessed by wall motion abnormalities, edema, myocardial salvage index, and delayed enhancement in acute reperfused STEMI. Methods and Results— We studied 450 patients 1–4 days after primary angioplasty in STEMI. T2-weighted and delayed-enhancement cardiac magnetic resonance was used for visualizing edema and scar to calculate myocardial salvage index. Cine-imaging was performed to assess wall motion abnormalities, which, in combination with edema, were considered diagnostic for RVI. Patients with RVI were compared with matched patients with isolated left ventricular infarction. The primary end point was the occurrence of a major adverse cardiac event: a composite of death, reinfarction, and congestive heart failure after a median follow-up period of 20.9 months. RVI was present in 69 patients, and 41 of 69 showed myocardial necrosis. In a multivariable stepwise forward logistic regression analysis, a high RV myocardial mass (odds ratio, 2.06; 95% confidence interval, 1.18–3.58; P=0.012) and a low Thrombolysis In Myocardial Infarction flow before angioplasty (odds ratio, 0.50; 95% confidence interval, 0.32–0.76; P=0.011) were associated with RVI. Cox regression analysis revealed RVI as the most statistically significant predictor of time to major adverse cardiac events (hazard-ratio, 3.36; 95% confidence interval, 1.99–5.66; P<0.001). Conclusions— RVI detected by cardiac magnetic resonance is a strong and independent predictor of clinical outcome after acute reperfused STEMI. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT01359306.

Imaging of nonthrombotic pulmonary embolism: Biological materials, nonbiological materials, and foreign bodies

Nonthrombotic pulmonary embolism is defined as embolization to the pulmonary circulation caused by a wide range of substances of endogenous and exogenous biological and nonbiological origin and foreign bodies. It is an underestimated cause of acute and chronic embolism. Symptoms cover the entire spectrum from asymptomatic patients to sudden death. In addition to obstruction of the pulmonary vasculature there may be an inflammatory cascade that deteriorates vascular, pulmonary and cardiac function. In most cases the patient history and radiological imaging reveals the true nature of the patients condition. The purpose of this article is to give the reader a survey on pathophysiology, typical clinical and radiological findings in different forms of nonthrombotic pulmonary embolism. The spectrum of forms presented here includes pulmonary embolism with biological materials (amniotic fluid, trophoblast material, endogenous tissue like bone and brain, fat, Echinococcus granulosus, septic emboli and tumor cells); nonbiological materials (cement, gas, iodinated oil, glue, metallic mercury, radiotracer, silicone, talc, cotton, and hyaluronic acid); and foreign bodies (lost intravascular objects, bullets, catheter fragments, intraoperative material, radioactive seeds, and ventriculoperitoneal shunts).

Dynamic CT Angiography after Abdominal Aortic Endovascular Aneurysm Repair: Influence of Enhancement Patterns and Optimal Bolus Timing on Endoleak Detection

PURPOSE To determine the time course of enhancement patterns in the aorta and endoleaks at dynamic computed tomographic (CT) angiography as well as their effect on the endoleak detection rate in patients who have undergone abdominal aortic endovascular aneurysm repair (EVAR). MATERIALS AND METHODS This retrospective study was approved by the local ethics committee and compliant with the Declaration of Helsinki. All patients gave written informed consent for the scientific analysis of their data. Seventy-one patients (mean age, 72 years ± 8 [standard deviation]) were retrospectively included after EVAR of the abdominal aorta. All patients underwent dynamic CT angiography with 10 unidirectional scan phases, followed by a venous phase. Endoleaks were detected visually in all scan phases; the magnitude of enhancement was assessed by using region-of-interest measurements in the aorta and the detectable endoleaks. Statistical analysis was performed with the χ(2) test, the paired t test, and analysis of variance with repeated measurements. RESULTS The highest mean aortic enhancement was achieved 12 seconds after the bolus-tracking threshold, and the highest mean endoleak enhancement was achieved 22 seconds after the bolus-tracking threshold. In total, 44 endoleaks were detected. The detection rates differed significantly in between the dynamic CT angiography phases (minimum, seven endoleaks at 2 seconds after the bolus-tracking threshold; maximum, 44 endoleaks at 27 seconds after the bolus-tracking threshold; P = .001). The highest detection rate was achieved when the contrast between aortic and endoleak enhancement reached its maximum. CONCLUSION Dynamic CT angiography revealed that the peak enhancement of endoleaks is significantly different than that of the aorta and that endoleaks may not be adequately evaluated with conventional biphasic CT protocols. The use of dynamic CT angiography is associated with a significantly increased detection rate of endoleaks compared with the detection rates at the time points of conventional biphasic CT.

Surgical management of delayed retrograde type A aortic dissection following complete supra-aortic de-branching and stent-grafting of the transverse arch

OBJECTIVES Hybrid endovascular procedures are rapidly evolving and have recently been adopted for high-risk patients deemed unsuitable for conventional aortic arch surgery. We describe here our initial experience with this technique, including the management of 2 patients who developed a retrograde type A aortic dissection post-de-branching. METHODS Between May 2010 and October 2012, 109 patients underwent conventional aortic arch repair at our institution. A further 9 high-risk patients with complex aortic arch pathology (median logistic EuroSCORE: 26, range: 11-41) were deemed unsuitable for conventional total aortic arch replacement and therefore underwent hybrid aortic arch repair. Complete supra-aortic de-branching, followed by endovascular stent-grafting (TEVAR) of the transverse arch and descending aorta, was performed in these high-risk patients. RESULTS In-hospital mortality was zero and no patient developed paraplegia/paraparesis due to spinal cord ischaemia. However, 2 patients (22%) developed retrograde type A aortic dissection on Days 10 and 12 post-TEVAR. Both patients had a dilated ascending aorta and received a stent graft containing bare metal springs at the proximal end. Emergency ascending aortic replacement was performed during moderate-to-mild hypothermia (28-34°C) and bilateral antegrade cerebral perfusion via cannulation of the de-branching prosthesis. A Hemashield prosthetic graft was anastomosed to the proximal stent graft in an elephant trunk technique. Both patients suffered from minor non-debilitating stroke, with 1 being discharged home and 1 transferred to a neurological rehabilitation centre 2 and 3 weeks after reoperation, respectively. CONCLUSIONS Retrograde type A aortic dissection after hybrid endovascular treatment of the aortic arch represents a new-most likely under-reported-pathology that may be successfully treated with open surgical repair. The use of stent grafts with protruding proximal bare springs and the implementation of oversizing and post-deployment ballooning should be avoided in patients undergoing hybrid arch procedures, particularly if the ascending aorta is dilated.

Role of Preprocedural Computed Tomography in Transcatheter Aortic Valve Implantation

UNLABELLED Transcatheter aortic valve implantation (TAVI) is currently considered an acceptable alternative for the treatment of patients with severe aortic stenosis and a high perioperative risk or a contraindication for open surgery. The benefit of TAVI significantly outweighs the risk of the procedure in patients requiring treatment that are not suitable for open surgery, and leads to a lower mortality in the one-year follow-up. The absence of a direct view of the aortic root and valve remains a challenge for the transcatheter approach. While direct inspection of the aortic valve during open surgery allows an adequate prosthesis choice, it is crucial for TAVI to know the individual anatomical details prior to the procedure in order to assure adequate planning of the procedure and proper prosthesis choice and patient selection. Among the imaging modalities available for the evaluation of patients prior to TAVI, computed tomography (CT) plays a central role in patient selection. CT reliably visualizes the dimensions of the aortic root and allows a proper choice of the prosthesis size. The morphology of the access path and relevant comorbidities can be assessed. The present review summarizes the current state of knowledge regarding the value of CT in the evaluation of patients prior to TAVI. KEY POINTS CT plays a central role in patient selection and planning prior to TAVI. ▶ CT reliably detects the dimensions of the aortic root including the size of the aortic annulus, the degree of valve calcification and the morphology of the access routes. ▶ CT provides a more accurate measurement of the aortic annulus than 2D TEE and CT is the only imaging modality that allows a risk assessment for paravalvular leakages based on the calcification of the aortic valve.

The systemic right ventricle in congenitally corrected transposition of the great arteries is different from the right ventricle in dextro-transposition after atrial switch: a cardiac magnetic resonance study.

BACKGROUND Patients with a congenitally corrected transposition of the great arteries show an increasing incidence of cardiac failure with age. In other systemic right ventricles, such as in dextro-transposition after atrial switch, excessive hypertrophy is a potential risk factor for impaired systolic function. In this trial, we sought to compare systemic function and volumes between patients with congenitally corrected transposition and those with dextro-transposition after atrial switch by using cardiac magnetic resonance imaging. METHODS AND RESULTS A total of 19 patients (nine male) with congenitally corrected transposition and 31 patients (21 male) with dextro-transposition after atrial switch were studied using a 1.5-Tesla scanner. Cine steady-state free-precession sequences in standard orientations were acquired for volumetric and functional imaging. Patient parameters were compared with those of a group of 25 healthy volunteers. Although patients with congenitally corrected transposition were older, they presented with higher right ventricular ejection fractions (p = 0.04) compared with patients with dextro-transposition. Patients with congenitally corrected transposition showed a weak negative correlation between age at examination and systemic ejection fraction (r = −0.18, p = 0.04) but no correlation between right ventricular myocardial mass index and ejection fraction. There was no significant difference in the right ventricular end-diastolic volumes between both patient groups. CONCLUSION Although patients with congenitally corrected transposition had a longer pressure load of the systemic right ventricle, ventricular function was better compared with that in patients with dextro-transposition after atrial switch. The results suggest that the systemic ventricles might have partly different physiologies. One difference could be the post-operative situation after atrial switch, which results in impaired atrial contribution to ventricular filling.