Asad Usman

Cardiac Magnetic Resonance T2 Mapping in the Monitoring and Follow-up of Acute Cardiac Transplant Rejection A Pilot Study

Background—Acute rejection is a major factor impacting survival in the first 12 months after cardiac transplantation. Transplant monitoring requires invasive techniques. Cardiac magnetic resonance (CMR), noninvasive testing, has been used in monitoring heart transplants. Prolonged T2 relaxation has been related to transplant edema and possibly rejection. We hypothesize that prolonged T2 reflects transplant rejection and that quantitative T2 mapping will concur with the pathological and clinical findings of acute rejection. Methods and Results—Patients were recruited within the first year after transplantation. Biopsies were graded according to the International Society for Heart Lung Transplant system for cellular rejection with immunohistochemistry for humoral rejection. Rejection was also considered if patients presented with signs and symptoms of hemodynamic compromise without biopsy evidence of rejection who subsequently improved with treatment. Patients underwent a novel single-shot T2-prepared steady-state free precession 4-chamber and 3 short axis sequences and regions of interest were drawn overlying T2 maps by 2 independent blinded reviewers. A total of 74 (68 analyzable) CMRs T2 maps in 53 patients were performed. There were 4 cellular, 2 humoral, and 2 hemodynamic rejection cases. The average T2 relaxation time for grade 0R (n=46) and grade 1R (n=17) was 52.5±2.2 and 53.1±3.3 ms (mean±SD), respectively. The average T2 relaxation for grade 2R (n=3) was 59.6±3.1 ms and 3R (n=1) was 60.3 ms (all P value <0.05 compared with controls). The T2 average in humoral rejection cases (n=2) was 59.2±3.3 ms and the hemodynamic rejection (n=2) was 61.1±1.8 ms (P<0.05 versus controls). The average T2 relaxation time for all-cause rejection versus no rejection is 60.1±2.1 versus 52.8±2.7 ms (P<0.05). All rejection cases were rescanned 2.5 months after treatment and demonstrated T2 normalization with average of 51.4±1.6 ms. No difference was found in ventricular function between nonrejection and rejection patients, except in ventricular mass 107.8±10.3 versus 127.5±10.4 g (P < 0.05). Conclusions—Quantitative T2 mapping offers a novel noninvasive tool for transplant monitoring, and these initial findings suggest potential use in characterizing rejections. Given the limited numbers, a larger multi-institution study may help elucidate the benefits of T2 mapping as an adjunctive tool in routine monitoring of cardiac transplants.

Metaanalysis of Procedural Stroke and Death among Octogenarians: Carotid Stenting versus Carotid Endarterectomy

S C d t d n the major trials assessing the efficacy of carotid endarerectomy (CEA) for stroke prevention, octogenarians were ither excluded or constituted a very small percentage of he study population because of the perceived risks of opration, risks of general anesthesia, and their presumed horter life expectancy. Stroke, which leads to increased orbidity and mortality in octogenarians, is more frequent s age increases. Because octogenarians account for one f the fastest growing segments of the United States popuation, the inevitably more frequent diagnosis of carotid tenosis in the elderly will lead to a therapeutic dilemma of erforming CEA or carotid artery stenting (CAS) in this ohort. The answer to this question has not yet been anwered by currently available randomized experimental ata. Carotid artery stenting has been proposed as a potenially safer alternative to CEA in octogenarians. In fact, ge greater than or equal to 80 years is a medical high risk riterion that satisfies Medicare reimbursement guidelines or CAS. But the lead-in phase of the Carotid Revascuarization Endarterectomy versus Stent Trial (CREST) nd the Carotid RX ACCULINK/RX ACCUNET Postpproval Trial to Uncover Unanticipated or Rare Events CAPTURE) registry both suggest that octogenarians ndergoing CAS may have higher stroke rates. On he other hand, numerous case series have suggested hat carotid endarterectomy can be performed safely in ctogenarians. Ideally, a randomized trial would be conducted to comare CAS with CEA. But a study appropriately powered to etect the miniscule differences between stroke rates be-

Myocardial T2-mapping and velocity mapping: Changes in regional left ventricular structure and function after heart transplantation

Monitoring post cardiac transplant (TX) status relies on frequent invasive techniques such as endomyocardial biopsies and right heart cardiac catheterization. The aim of this study was to noninvasively evaluate regional myocardial structure, function, and dyssynchrony in TX patients. Myocardial T2‐mapping and myocardial velocity mapping of the left ventricle (basal, midventricular, and apical short‐axis locations) was applied in 10 patients after cardiac transplantation (49 ± 13years, n = 2 with signs of mild rejection, time between TX and MRI = 1–64 months) and compared to healthy controls (n = 20 for myocardial velocity mapping and n = 14 for T2). Segmental analysis based on the 16‐segment American Heart Association model revealed increased T2 (P = 0.0003) and significant (P < 0.0001) reductions in systolic and diastolic radial and long‐axis peak myocardial velocities in TX patients without signs of rejection compared to controls. Multiple comparisons of individual left ventricular segments demonstrated reductions of long‐axis peak velocities in 50% of segments (P < 0.001) while segmental T2 values were not significantly different. Systolic radial as well as diastolic radial and long‐axis dyssynchrony were significantly (P < 0.04) increased in TX patients indicating less coordinated contraction, expansion, and lengthening. Correlation analysis revealed moderate but significant (P < 0.010) inverse relationships between myocardial T2 and long‐axis peak velocities suggesting a structure–function relationship between altered T2 and myocardial function. Magn Reson Med 70:517–526, 2013.

Eight-year institutional review of carotid artery stenting

OBJECTIVES Vascular surgeons have increasingly become proficient in carotid artery stenting (CAS) as an alternative treatment modality for cervical carotid artery occlusive disease. We analyzed our early and late outcomes of CAS over the last 8 years. METHODS We report a single-center retrospective review of 388 carotid bifurcation lesions treated with CAS using cerebral embolic protection from May 2001 to July 2009. Data analysis includes demographics, procedural records, duplex exams, arteriograms, and two-view plain radiographs over a mean follow-up time of 23.0 months (interquartile range, 10.9-35.4). RESULTS At the time of treatment, the mean age of the entire cohort (76% men and 24% women) is 71 years; 13% were >/=80 years of age, and 31% had a prior history of either carotid endarterectomy (CEA) and/or external beam neck irradiation (XRT). The mean carotid stenosis is 80%, and asymptomatic lesions represent 69% of the group. Overall 30-day rates of death, stroke, and myocardial infarction are 0.5%, 1.8%, and 0.8%, respectively. The combined death/stroke rate at 30 days is 2.3%. The 30-day major/minor stroke rates for analyzed subgroups are statistically significant only for XRT/recurrent stenosis vs de novo lesions, 0% and 2.6% (P = .03), but not for asymptomatic vs symptomatic patients, 1.9% and 1.7% (P = .91) and age <80 vs >/=80, 2.0% and 1.8% (P = .52), respectively. At long-term, the freedom from all strokes at 12, 24, 36, and 48 months was 99.2%, 97.6%, 96.7%, and 96.7%, respectively. At late follow-up, the restenosis rate is 3.5%. Restenosis rates for recurrent stenosis/XRT vs de novo lesions are 2.7% and 3.4% (P = .39). Among the restenotic lesions were two associated type III stent fractures in de novo lesions, both of which were closed-cell stents. An additional two other type I fractures have been identified, yielding a stent fracture rate of 5.5%. The late death rate for the entire group is 16.8%, with one stent-related death secondary to ipsilateral stroke at 20 months (0.3% death rate). CONCLUSIONS Vascular surgeons performing CAS with embolic protection can achieve good early and late outcomes that are comparable to CEA benchmarks. Late stent failures (stroke, restenosis, and/or stent fatigue), while uncommon, are a recognized delayed problem.

Adult presentation of a familial-associated vein of galen aneurysmal malformation: Case report

BACKGROUND AND IMPORTANCE: Vein of Galen aneurysmal malformations (VGAMs) arise from persistent arteriovenous shunting from primitive choroidal vessels into the median prosencephalic vein of Markowski, the embryonic precursor of the vein of Galen. VGAMs rarely present past infancy, and their natural history in adults is unknown. We report the first case of a familial-associated VGAM in an asymptomatic adult female patient. The clinical features of this case are presented alongside a systematic review of the literature on adult VGAM cases to assess the natural history, clinical management, and genetic basis of this rare neurovascular lesion. CLINICAL PRESENTATION: A previously healthy 44-year-old woman with a family history of a VGAM in a stillborn presented with an 8-week onset of dizziness and vertigo that spontaneously resolved. Time-resolved magnetic resonance angiography identified a choroidal VGAM. No intervention was undertaken at this time because of the patients asymptomatic status after 9 months of follow-up. CONCLUSION: Based on our review of the literature, this is the first case report of a familial-associated VGAM in an adult patient and suggests that VGAM development can be genetically linked. Of 15 adult VGAM cases previously reported, all patients were either symptomatic or treated, thus precluding determination of VGAM natural history in adults. Patient outcomes correlated with the severity of presenting symptoms, which ranged from asymptomatic to immediately life-threatening. We hypothesize that self-selection may render VGAMs to be more benign for them to persist past childhood. Further investigation of the molecular biology underlying VGAM development is warranted.

Contouring Guidelines for the Axillary Lymph Nodes for the Delivery of Radiation Therapy in Breast Cancer: Evaluation of the RTOG Breast Cancer Atlas.

PURPOSE The purpose of this study was to identify the axillary lymph nodes on pretreatment diagnostic computed tomography (CT) of the chest to determine their position relative to the anatomic axillary borders as defined by the Radiation Therapy Oncology Group (RTOG) breast cancer atlas for radiation therapy planning. METHODS AND MATERIALS Pretreatment diagnostic CT chest scans available for 30 breast cancer patients with clinically involved lymph nodes were fused with simulation CT. Contouring of axillary levels I, II, and III according to the RTOG guidelines was performed. Measurements were made from the area of distal tumor to the anatomic borders in 6 dimensions for each level. RESULTS Of the 30 patients, 100%, 93%, and 37% had clinical involvement of levels I, II, and III, respectively. The mean number of lymph nodes dissected was 13.6. The mean size of the largest lymph node was 2.4 cm. Extracapsular extension was seen in 23% of patients. In 97% of patients, an aspect of the involved lymph node lay outside of the anatomic border of a level. In 80% and 83% of patients, tumor extension was seen outside the cranial (1.78 ± 1.0 cm; range, 0.28-3.58 cm) and anterior (1.27 ± 0.92 cm; range, 0.24-3.58 cm) borders of level I, respectively. In 80% of patients, tumor extension was seen outside the caudal border of level II (1.36 ± 1.0 cm, range, 0.27-3.86 cm), and 0% to 33% of patients had tumor extension outside the remaining borders of all levels. CONCLUSIONS To cover 95% of lymph nodes at the cranial and anterior borders of level I, an additional clinical target volume margin of 3.78 cm and 3.11 cm, respectively, is necessary. The RTOG guidelines may be insufficient for coverage of axillary disease in patients with clinical nodal involvement who are undergoing neoadjuvant chemotherapy, incomplete axillary dissection, or treatment with intensity modulated radiation therapy. In patients with pretreatment diagnostic CT chest scans, fusion with simulation CT should be considered for tumor delineation.

Late Stent Fractures after Endoluminal Treatment of Ostial Supraaortic Trunk Arterial Occlusive Lesions

PURPOSE Percutaneous catheter-based treatment of supraaortic trunk arterial occlusive lesions obviates the need for extraanatomic bypass or median sternotomy. Although early results have been encouraging, late outcomes have yet to be defined. Reported are long-term outcomes of supraaortic trunk stent placement with particular attention to structural failures. MATERIALS AND METHODS This was a retrospective review of 27 ostial supraaortic trunk lesions managed with balloon-expandable or self-expandable stents. Treated vessels were innominate (n = 9), common carotid (n = 8), and subclavian (n = 10). Access to the target lesion was achieved either antegrade via the femoral artery (n = 13), retrograde through the brachial artery (n = 2), or through a cutdown on the common carotid artery (n = 12). Restenosis and stent integrity were detected with duplex imaging, computed tomography, conventional arteriography, and plain radiography. Mean follow-up time is 34 months. RESULTS Mean age was 68 years (eight men and 19 women), and mean stenosis was 85%. Preprocedural symptoms, including stroke, transient ischemic attack, arm fatigue, digital ischemia, and angina were present in 85% (23 of 27) of the group. At 30 days, there were no deaths, myocardial infarctions, or strokes. During follow-up, three type IV stent fractures in the innominate were detected as well as two midbody stent crush deformities with significant restenosis (one innominate and one common carotid). All stent failures were identified in heavily calcified lesions. CONCLUSIONS Endoluminal stent placement in supraaortic trunk lesions is a viable early solution; however, mid- to long-term restenosis caused by bare metal fatigue and fractures, particularly in cases of calcified innominate artery lesions, are a worrisome finding.

Cold ischaemic time and time after transplantation alter segmental myocardial velocities after heart transplantation

OBJECTIVES The aim of this study was to investigate changes in segmental, three-directional left ventricular (LV) velocities in patients after heart transplantation (Tx). METHODS Magnetic resonance tissue phase mapping was used to assess myocardial velocities in patients after Tx (n = 27) with normal LV ejection fraction (63 ± 5%) and those without signs of rejection. Regional wall motion and dyssynchrony were analysed in relation to cold ischaemic time (150 ± 57 min, median = 154 min), age of the donor heart (35 ± 13 years, median = 29 years), time after transplantation (32 ± 26 months, median = 31 months) and global LV morphology and function. RESULTS Segmental myocardial velocities were significantly altered in patients with cold ischaemic times >155 min resulting in an increase in peak systolic radial velocities (2 of 16 segments, P = 0.03-0.04) and reduced segmental diastolic long-axis velocities (5 of 16 segments, P = 0.01-0.04). Time after transplantation (n = 8 patients <12 months after Tx vs n = 19 >12 months) had a significant influence on systolic radial velocities (increased in 2 of 16 segments, P = 0.01-0.04) and diastolic long-axis velocities (reduced in 5 of 16 segments, P = 0.02-0.04). Correlation analysis and multiple regression revealed significant relationships of cold ischaemic time (R = -0.384, P = 0.048), the donor hearts age (β= 0.9, P = 0.01) and time from transplantation (β= -0.36, P = 0.03) with long-axis diastolic dyssynchrony. CONCLUSIONS Time after transplantation and cold ischaemic time strongly affect segmental systolic and diastolic motion in patients after Tx. The understanding of alterations in regional LV motion in the transplanted heart under stable conditions is essential in order to utilize this methodology in the future as a potentially non-invasive means of diagnosing transplant rejection.

Clinical utility of cardiac magnetic resonance T2 mapping for acute myocardial edema

Objective To evaluate the potential clinical utility of T2 quantitative mapping for myocardial edema in acute disease pathology - myocarditis, myocardial infarction, TakoTsubo cardiomyopathy, and transplant rejection. Background Edema is ag eneric tissue response to acute myocardial injury and, therefore; a potential marker of impending tissue damage. Currently in clinical use, T2 weighted imaging provides a qualitative technique in assessing myocardial edema. We hypothesize that quantitative T2 mapping in patients with suspected cases of myocarditis, myocardial infarction (AMI), and cardiac transplant rejection will provide a more sensitive and specific diagnostic prediction than with T2W imaging, and add to other imaging techniques. Method

Detection of renal dysfunction by point-of-care creatinine testing in patients undergoing peripheral MR angiography.

OBJECTIVE The objective of our study was to analyze the effectiveness of prestudy questionnaires in identifying at-risk patients and estimate the prevalence of chronic kidney disease (CKD), nephrogenic systemic fibrosis risk factors, and other comorbidities in patients scheduled to undergo lower extremity MR angiography (MRA) studies using gadolinium-based contrast agents. MATERIALS AND METHODS Patent demographics, comorbidities, contrast type, and point-of-care (POC) serum creatinine values were recorded from the medical records of consecutive patients undergoing lower extremity MRA examinations in a single year. Patients were divided into groups by CKD stage (non-CKD, stage III, stage IV, or stage V) on the basis of estimated glomerular filtration rate values determined from POC creatinine results. Patient awareness of a history of CKD was noted if patients admitted to any form of CKD on prestudy questionnaires. RESULTS Of 199 patients, 72 patients (36.2%) had stage III CKD, six patients (3.0%) had stage IV CKD, and seven patients (3.5%) had stage V CKD. Comorbidities-including smoking status, transplant status, and presence of diabetes, hypertension, and coronary artery disease-as well as administered contrast type and dosage showed significant differences among the CKD groups (p < 0.05). Only five stage III patients (7%) were aware of any history of renal dysfunction, whereas three stage IV patients (50%) and seven stage V patients (100%) admitted any history of renal dysfunction via questionnaires. CONCLUSION Compared with POC creatinine testing, a prestudy questionnaire used alone is ineffective in identifying all patients with histories of CKD who are scheduled to undergo gadolinium-based peripheral MRA studies.