Consensus Document of the International Union of Angiology (IUA)-2013. Current concept on the management of arterio-venous management.

Arterio-venous malformations (AVMs) are congenital vascular malformations (CVMs) that result from birth defects involving the vessels of both arterial and venous origins, resulting in direct communications between the different size vessels or a meshwork of primitive reticular networks of dysplastic minute vessels which have failed to mature to become 'capillary' vessels termed "nidus". These lesions are defined by shunting of high velocity, low resistance flow from the arterial vasculature into the venous system in a variety of fistulous conditions. A systematic classification system developed by various groups of experts (Hamburg classification, ISSVA classification, Schobinger classification, angiographic classification of AVMs,) has resulted in a better understanding of the biology and natural history of these lesions and improved management of CVMs and AVMs. The Hamburg classification, based on the embryological differentiation between extratruncular and truncular type of lesions, allows the determination of the potential of progression and recurrence of these lesions. The majority of all AVMs are extra-truncular lesions with persistent proliferative potential, whereas truncular AVM lesions are exceedingly rare. Regardless of the type, AV shunting may ultimately result in significant anatomical, pathophysiological and hemodynamic consequences. Therefore, despite their relative rarity (10-20% of all CVMs), AVMs remain the most challenging and potentially limb or life-threatening form of vascular anomalies. The initial diagnosis and assessment may be facilitated by non- to minimally invasive investigations such as duplex ultrasound, magnetic resonance imaging (MRI), MR angiography (MRA), computerized tomography (CT) and CT angiography (CTA). Arteriography remains the diagnostic gold standard, and is required for planning subsequent treatment. A multidisciplinary team approach should be utilized to integrate surgical and non-surgical interventions for optimum care. Currently available treatments are associated with significant risk of complications and morbidity. However, an early aggressive approach to elimiate the nidus (if present) may be undertaken if the benefits exceed the risks. Trans-arterial coil embolization or ligation of feeding arteries where the nidus is left intact, are incorrect approaches and may result in proliferation of the lesion. Furthermore, such procedures would prevent future endovascular access to the lesions via the arterial route. Surgically inaccessible, infiltrating, extra-truncular AVMs can be treated with endovascular therapy as an independent modality. Among various embolo-sclerotherapy agents, ethanol sclerotherapy produces the best long term outcomes with minimum recurrence. However, this procedure requires extensive training and sufficient experience to minimize complications and associated morbidity. For the surgically accessible lesions, surgical resection may be the treatment of choice with a chance of optimal control. Preoperative sclerotherapy or embolization may supplement the subsequent surgical excision by reducing the morbidity (e.g. operative bleeding) and defining the lesion borders. Such a combined approach may provide an excellent potential for a curative result. Conclusion. AVMs are high flow congenital vascular malformations that may occur in any part of the body. The clinical presentation depends on the extent and size of the lesion and can range from an asymptomatic birthmark to congestive heart failure. Detailed investigations including duplex ultrasound, MRI/MRA and CT/CTA are required to develop an appropriate treatment plan. Appropriate management is best achieved via a multi-disciplinary approach and interventions should be undertaken by appropriately trained physicians.

Renal artery stenosis: endovascular flow wire study for validation of Doppler US.

PURPOSE: To compare the accuracy of proximal and peripheral Doppler parameters for detection of renal artery stenosis (RAS). MATERIALS AND METHODS: The authors obtained absolute velocities and peripheral Doppler waveforms in 16 stenotic and 14 normal renal arteries by using a 0.45-mm endovascular flow wire. Hemodynamically significant stenosis was established by measuring transstenotic invasive pressure gradients, with a 10 mm Hg or greater pressure drop indicating RAS. Accuracy of the Doppler parameters and of digital subtraction angiographic (DSA) results were compared by using receiver operating characteristic analysis. RESULTS: Measurements of absolute velocities at the site of the stenosis (maximal peak systolic velocity [PSVmax], PSV ratio, renal artery-to-aortic PVS ratio) showed high accuracy for diagnosis of RAS similar to that of DSA (areas under the ROC curve were 0.96, 0.97, 0.93, respectively). The distal intrarenal Doppler indexes (notably loss of early systolic peak, acceleration, acceleration time, pulsatility index, and resistive index) did not show statistically significant correlation with RAS. CONCLUSION: Doppler measurements in the main renal artery correlate well with RAS. The intrarenal Doppler spectrum, however, has no diagnostic value. The authors conclude that duplex Doppler US is not a suitable screening test for RAS.