Operative Evaluation of Renal and Visceral Arterial Reconstructions Using Duplex Sonography

Louis M. Messina and Donald Baril

Reconstructions of the renal and splanchnic arteries are among the most technically challenging operations vascular surgeons perform. Inadequate treatment of a renal artery stenosis can result in persistent, uncontrolled hypertension or loss of renal function after renal artery repair or, in the case of mesenteric artery disease, recurrent acute or chronic ischemia. Hansen and associates noted that after reoperation for failure of primary renal revascularization, there is a significantly increased risk of eventual kidney failure and need for dialysis. Of their 20 patients undergoing secondary operation for a failed primary operation, 35% eventually required dialysis, compared with 4% of patients having a primary operation. Stanley and colleagues cite a 43% nephrectomy rate after a failed primary renal revascularization procedure. Others report an 11% recurrence rate for chronic ischemia and 6.4% recurrence rate for acute intestinal ischemia, with an accompanying 85.7% mortality rate in this subset of patients. It is therefore critically important to document the adequacy of renal and mesenteric revascularization at the initial operation to minimize the incidence of persistent or recurrent renal or mesenteric artery occlusive disease.

The long-term patency rates in renal and mesenteric artery repairs depend in part on achieving technical perfection at the initial operation. Therefore a reliable, safe, and rapid means of interrogating renal and visceral vessels after repair is required to detect technical defects at the time of operation, thus allowing immediate repair with the goal of improving both immediate and long-term outcomes.

Intraoperative ultrasonography is an ideal tool for assessing technical results after mesenteric and renal revascularizations, providing both anatomic and physiologic information. Intraoperative ultrasonography, including B-mode imaging and Doppler blood flow assessment, overcomes many shortcomings of intraoperative arteriography. B-mode duplex scanning provides real-time multiplanar images under more normal hemodynamic conditions along the course of a vessel, thus showing exact anatomic detail in multiple views.

In addition to visualizing the anatomy of the vessel, Doppler blood flow assessment provides important data regarding changes in blood flow velocity or turbulence, thus aiding in detecting a lesion and determining its hemodynamic significance. Vessel kinks, thrombus, residual disease, intimal flaps, and dissections can be localized using B-mode ultrasonography, and their hemodynamic characteristics can be assessed with Doppler spectral analysis. Operative ultrasonography also avoids the use of contrast agents and the need to reclamp the aorta.

Limitations of operative ultrasonography can include the inability to assess distal arterial branches adequately, so distal thrombus or atherosclerotic disease may be missed; the inability to obtain an adequate angle of insonation to assess Doppler blood flow velocities; the inability to adequately penetrate through synthetic material; and user inexperience.

Duplex ultrasonography is an effective technique to provide accurate anatomic assessment of the vessels in the operating room. Duplex can be used experimentally to study splanchnic blood flow responses to various vasoactive agents. One approach is to use a small 7.5-MHz probe placed in a sterile sleeve accompanied by copious amounts of acoustic gel. The wound is filled with saline, and the surgeon places the probe directly over the area of reconstruction to be studied. Arteries under study are first identified at their origin along the aorta. Multiple transverse B-mode gray-scale images are obtained along the course of the reconstructed arteries, and any defects are imaged. Using longitudinal views, color flow images are then used to direct Doppler spectral analysis to insonate at the origins and endpoints of the endarterectomy, as well as to determine areas of increased or decreased blood flow velocity or turbulence (Figures 1 and 2).

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

1. Technical Aspects of Percutaneous Carotid Angioplasty and Stenting for Arteriosclerotic Disease
2. In-Situ Treatment of Aortic Graft Infection with Prosthetic Grafts and Allografts
3. Treatment of Acute Upper Extremity Venous Occlusion
4. Intraoperative Assessment of the Technical Adequacy of Carotid Endarterectomy

Stay updated, free articles. Join our Telegram channel

Join

Full access? Get Clinical Tree