Faculty Bibliography

A 49-year-old woman with mitral and tricuspid mechanical valve prostheses developed marked weight gain with increasing abdominal girth and facial plethora 4 weeks after anticoagulation was temporarily interrupted for abdominal surgery. Transthoracic and transesophageal echocardiography documented severe tricuspid stenosis and regurgitation. The two discs of the tricuspid prosthesis were immobilized, half open and half closed. The prosthesis was replaced and the patient did well

PURPOSE/OBJECTIVE:Successful use of the distal adjunctive arteriovenous fistula (dAVF) for the enhancement of prosthetic graft patency rates in the crural position is critically dependent on the qualitative and quantitative aspects of the arterial and venous runoff. Precise technical performance of the fistula is equally vital to secure optimal results. The purpose of this study was to determine current prosthetic graft patency and limb salvage rates using a modified version of the common ostium dAVF. METHODS:The standard method to create the common ostium variant of dAVF has been modified to improve apposition of the "otomy" sites of the artery and vein, avoid twisting and stenosis by terminating the fistula suture line at the artery-vein junctures, reshaping the ovoid ostium to a rectangular shape, and finally, use of multiple interrupted heel-toe sutures. RESULTS:Since 1979 we have created 290 fistulas in 281 patients who required leg revascularization procedures. In different time periods we have documented improving graft patency and limb salvage rates. Fistula patency, reflected by annual attrition rates of 13% to 26% per year, continues as a challenge for long-term results. Current 3-year secondary cumulative graft patency and limb salvage rates by life table analysis are 61% and 74%, respectively. The conduit material may play a role with regard to steal phenomena and the need for banding techniques. CONCLUSION/CONCLUSIONS:Configuration of the adjunctive dAVF may impact on prosthetic graft patency in the crural position. In addition, the type of graft material used for bypass may be instrumental in preventing or precipitating the steal phenomenon. These issues require further study to better understand flow dynamics, patterns of intimal hyperplasia, and blood distribution as a function of conduit material and impedance of the arterial and venous runoff.

A 37 year old man with recurrent episodes of endocarditis was found to have a large left coronary arteriovenous fistula communicating with the right atrium. The origin and termination of the fistula were identified using computed tomography and two-dimensional Doppler echocardiography. Coronary angiography confirmed the diagnosis and the patient underwent a successful operation

The change in contractility with increasing heart rate was studied in the left ventricle of dogs and in isolated trabeculae carneae of cats. For some of the studies in situ a transient isovolumic state was created by aortic occlusion. At physiological temperatures the frequency-force relationship is flatter than at room temperature and at the same temperature it is flatter in vivo than in vitro. The frequency-(dF/dt)max relationship is steeper than the frequency-force relationship at both temperatures in vivo and in vitro. The frequency-(dF/dt)max relationship is steeper in vitro than it is in situ, although the discrepancy is less marked than in the case of the frequency-force relationship. It is concluded that 'staircase' plays less of a physiological role in adjustment of contractile state in situ than might be inferred from studies of isolated tissue