Critical lower-limb ischemia: the diagnostic performance of dual-phase injection MR angiography (including high-resolution distal imaging) compared with digital subtraction angiography.

PURPOSE: To prospectively compare contrast-enhanced (CE) magnetic resonance (MR) angiography against digital subtraction angiography (DSA) in patients with critical lower-limb ischemia. MATERIALS AND METHODS: Thirty patients with critical lower limb ischemia underwent both CE MR angiography and DSA. CE MR angiography commenced with a dedicated high-resolution study of the below-knee arteries followed by a three-station bolus-chase examination. Two blinded observers recorded the severity of the most significant stenosis within each arterial segment. Interobserver agreement was calculated and, with DSA as the reference standard, the sensitivity and specificity of CE MR angiography for the detection of significant stenosis (>or=50% luminal narrowing) or occlusion was calculated. RESULTS: All 390 arterial segments were scored by both observers. Sensitivity was higher in the distal segments (92%-96%) compared with the proximal segments (69%-79%). Specificity was similar in distal (90%-91%) and more proximal segments (86%-96%). Overall, interobserver agreement was excellent (kappa = 0.95 for CE MR angiography and DSA) and was superior within the distal segments. Twenty-eight segments that were considered occluded on DSA were shown to be patent on CE MR angiography and 16 segments that were considered occluded on CE MR angiography were shown to be patent on DSA. CONCLUSIONS: In patients with critical lower-limb ischemia, CE MR angiography with high-resolution distal imaging is highly accurate for assessment of the below-knee arteries. Both DSA and CE MR angiography may identify patent vessels that are considered occluded based on the other modality.

Tetralogy of Fallot: Late outcome after repair and surgical implications.

Cardiac surgery has transformed the outcome for patients with tetralogy of Fallot. Repair has conveyed excellent long-term results with most patients remaining well and leading normal lives. However, there are problems with late morbidity and mortality primarily due to right ventricular dysfunction, exercise intolerance, arrythmia, and sudden cardiac death. There has been a dynamic shift in our surgical approach to managing patients with tetralogy over the past 5 decades. This in part accounts for persisting difficulties in predicting late outcome for evry single patient with repaired tetralogy of Fallot. There are, however, several confounding variables, influencing long-term outcome for these patients, namely the underlying anatomical substrate, age at repair, surgical approach to repair, and residual hemodynamic abnormalities. It is gratifying to see that recent knowledge accumulated from long-term follow-up studies is influencing contemporary surgical practice. Individualized strategies aiming to minimize the potential for free pulmonary regurgitation, and the long-term detrimental effects associated with it, need to continue to develop. Preservation of right ventricular and pulmonary valve function combined with early restoration of normal pulmonary blood flow are likely to convey an even better long-term outlook for these patients. Further follow-up studies with assessment of bi-venticular function, however, are needed in both our older and contemporary cohorts with repaired tetralogy of Fallot. Copyright 2000 by W.B. Saunders Company