Sixteen multidetector row computed tomography of pulmonary veins: 3-months' follow-up after treatment of paroxysmal atrial fibrillation with cryothermal ablation

The aim of the study was to assess pulmonary veins (PVs) for the presence of stenosis 3 months after cryothermal ablation (CA) with a new method of electrical isolation of PVs using contrast-enhanced 16 multidetector row computed tomography (MDCT). Twenty four patients with symptomatic atrial fibrillation underwent CA in 46 PVs. MDCT of PVs was performed before the treatment and after 3-months' follow-up. Following cryoablation, 13/24 (54%) patients showed clinical improvement and had reduced attacks of atrial fibrillation. The dimensions of the treated PVs remained unchanged: the coronal ostial diameter was 19.1 +/- 2.4 preprocedural versus 18.6 +/- 2.4 mm at follow-up, p > 0.05; the ratio of the coronal and axial diameters at the ostium was 1.2 +/- 0.2 versus 1.2 +/- 0.1, p > 0.05, respectively, and the coronal diameter of the proximal 10 mm was 17.1 +/- 2.5 mm versus 16.5 +/- 2.2 mm, p > 0.05, respectively. CA is a promising technique for electrical isolation of PVs that has not been associated with stenosis at the orifice and the proximal 10 mm of the PVs after 3-months' follow-up. MDCT is a noninvasive, fast and comfortable method for assessment of PVs in a three-dimensional manner prior to ablative treatment and during the follow-up

Sirolimus-eluting stents to abolish intimal hyperplasia and improve flow in porcine arteriovenous grafts - A 4-week follow-up study

Background - The patency of arteriovenous ( AV) expanded polytetrafluoroethylene (ePTFE) hemodialysis grafts is severely compromised by intimal hyperplasia (IH) at the venous anastomosis and in the venous outflow tract. We addressed the potential of primary placement of a sirolimus-eluting stent (SES) in a validated porcine model. Methods and Results - In 25 pigs, ePTFE AV grafts were created bilaterally between the carotid artery and the jugular vein, whereupon a self-expandable nitinol stent ( 14 SESs and 11 bare-metal stents) was implanted over the venous anastomosis in 1 of the 2 grafts. After exclusion of technical failures and 1 unilateral occlusion, 16 pigs ( 9 SESs and 7 bare-metal stents) were included for further analysis. After 28 days, we measured graft flow and performed quantitative angiography. The pigs were then euthanized, and grafts with adjacent vessels were excised for histological analysis. Minimal luminal diameter was substantially larger in the SES group compared with unstented controls ( 5.9 +/- 0.2 versus 3.8 +/- 0.4 mm, respectively, P = 0.01), which was accompanied by more prominent graft flow ( SES, 1360 +/- 89 mL/min versus unstented, 861 +/- 83 mL/min, P = 0.05). IH at the venous anastomosis was 77% less in the SES group compared with unstented controls (0.44 +/- 0.05 versus 1.92 +/- 0.5 mm(2), respectively, P = 0.01), whereas IH increased markedly when bare-metal stents were used (5.7 +/- 1.4 mm(2), P = 0.05). Conclusions - SESs in the venous outflow of AV grafts significantly reduce IH and increase vessel diameter and graft flow compared with unstented grafts. These findings suggest that SESs have the potential to improve primary patency of AV grafts in hemodialysis patients

Tumor diameter and volume assessed by magnetic resonance imaging in the prediction of outcome for invasive cervical cancer

Objective. The aim of this study was to evaluate the predictive value of pretherapeutic magnetic resonance imaging (MRI)-based measurements of tumor diameter and volume with regard to recurrent disease. Methods. NM on 0.5- or 1.5-T scanners was performed in 126 consecutive women with invasive carcinoma of the uterine cervix. Initial tumor diameter and volume were determined on T-2-weighted images; volume was calculated by the standard technique of multiplying the sum of the areas by the slice thickness. Patients were treated by radical surgery, radiotherapy, or a combined approach based on clinical International Federation of Gynecology and Obstetrics (FIGO) stage and individual patient criteria. Clinical data (patient age and FIGO stage), MRI-derived tumor dimensions (diameter and volume), and histological findings (tumor invasion depth and lymph-node involvement) were associated and linked to patient outcome. Results. MRI-based tumor diameter correlated strongly with histological tumor invasion depth and lymph-node status (P < 0.01 and P = 0.01) while tumor volume on MRI was significantly associated only with tumor invasion depth into adjacent tissues (P < 0.01). Univariate analysis demonstrated graphically that MRI-derived tumor diameter and volume and clinical FIGO stage are associated with progression-free survival. Correlation analysis showed a strong association between MRI-derived tumor diameter and volume on MRI (r = 68%, P < 0.01) and also demonstrated a correlation between tumor diameter on MRI and FIGO stage Ib (Ib1 versus Ib2) cervical tumors (r = 46.7%, P < 0.01). Conclusion. Tumor diameter and volume, determined by pretreatment MRI examinations, predict progression-free survival for patients with invasive cervical carcinoma. This study demonstrates the value of MRI as an adjunct to clinical evaluation of invasive cervical cancer, providing more complete assessment of morphological risk factors important in patient prognosis and treatment planning. (C) 2001 Academic Press

The cardiac MRI substudy to ongoing telmisartan alone and in combination with ramipril global endpoint trial/telmisartan randomized assessment study in ACE-intolerant subjects with cardiovascular disease: analysis protocol and baseline characteristics

Background: The ONTARGET and TRANSCEND clinical trials were designed to investigate the cardioprotective effects of telmisartan 80 mg and ramipril 10 mg, alone and in combination, in patients at high risk of cardiovascular disease. Cardiac MRI enables investigation of mechanistic effects of these agents on cardiac structural and functional variables. Here, we report the design, analysis protocol, reproducibility and relevant quality control procedures, and baseline patient characteristics of the ONTARGET/TRANSCEND cardiac MRI substudy. MRI was undertaken in 330 subjects enrolled in ONTARGET, and 38 subjects in TRANSCEND, across eight centers in six countries. Analyses were performed by two independent analysts using guide-point modeling. Cases with discrepancies in LV mass (LVM) of >5% were independently reanalyzed. Cases with discrepancies in end-diastolic volume (EDV) of >5%, or end-systolic volume (ESV) of >12%, were then reconciled by consensus. Results: Baseline characteristics were broadly similar to the main ONTARGET/TRANSCEND trials, except for a higher frequency of coronary artery disease and Asian ethnicity in the substudy. Reproducibility of MRI analyses (mean ± SD) were 2.8 ± 3.7 ml in EDV, -0.3 ± 3.6 ml in ESV, 3.1 ± 3.3 ml in SV, 1.1 ± 1.8% in EF, and 0.4 ± 4.5 g in LVM. Subgroup analyses revealed increased ESV and LVM, and reduced EF, in subjects with a history of either coronary artery disease or myocardial infarction. Conclusions: The ONTARGET/TRANSCEND cardiac MRI substudy protocol provides for a reliable assessment of the effects of telmisartan and ramipril, alone and in combination, on cardiac structural and functional parameters over a 2-year follow-up period