Albert K. Chin

The effect of valvulotomy on the flow rate through the saphenous vein graft: Clinical implications * ** ★

Potential differences in flow rates between reversed and in situ saphenous vein bypass grafts were evaluated. One hundred ten greater saphenous vein segments containing isolated valves were examined with fiber-optic angioscopy during pulsatile and nonpulsatile flow. Valve competency was determined, and the degree of luminal obstruction caused by the valve during reversed flow was calculated with caliper measurements of the video image. Flow measurements were obtained before and after valvulotomy, in reversed and nonreversed vein orientations. Increased flow rates occurred during pulsatile irrigation only, after valvulotomy in vein segments with diameters less than 2.5 mm (p less than 0.001, Bonferroni t test). In these small-diameter vein segments, the flow rate in reversed valve-intact vein was 94.4 +/- 28.9 ml/min (mean +/- 1 standard deviation), the flow rate in reversed valve-disrupted vein was 136.4 +/- 36.5 ml/min, and the flow rate in nonreversed valve-disrupted vein was 137.8 +/- 31.3 ml/min. In 22 vein segments, luminal obstruction caused by the intact valve was measured angioscopically. A small valve orifice was found to be related to a large increase in flow rate after valvulotomy (p less than 0.02, least-squares regression). In addition, veins with diameters less than 2.5 mm have significantly smaller valve orifices compared with veins with diameters greater than 2.5 mm. These results present important clinical implications as the number of distal extremity reconstructions increases.

An Improved Technique for the Internal Mammary Artery Coronary Bypass Graft Procedure

Abstract An improved technique for internal mammary artery graft preparation is described. Following cautery dissection of the internal mammary artery (IMA) pedicle, the pedicle investing fascia is incised to the adventitial level along a single plane. This incision allows the tissue around the internal mammary artery to fall away and severs the muscular constrictions that often surround the internal mammary artery. Balloon calibration is performed to identify remaining constrictions and to relieve internal mammary artery spasm. A shear force limiting gauge insures that the exerted balloon force remains below the level demonstrated to cause intimal damage during electron microscopic studies. This technique allows full internal mammary artery distention without the devascularizing effects of full skeletonization. Distention of the distal internal mammary artery provides an enlarged hood to facilitate suture placement. Elongation of the internal mammary artery during balloon calibration aids in the performance of sequential grafts. This technique has been applied to 793 patients over the past five years. Postcalibration flow rates increased 3‐ to 18‐fold over precalibration flow rates. Two early occlusions occurred during this series, one due to endothelial strippage prior to the development and use of the shear force limiting gauge. Follow‐up showed 93.3% of patients to be asymptomatic. This combination of fascial incision and balloon calibration appears to offer safe technical and functional improvements to the performance of the internal mammary artery graft.

Combined thrombectomy and dilation for the treatment of acute lower extremity arterial thrombosis

Our experience with combined balloon catheter thrombectomy and balloon dilation for the treatment of acute thrombosis is reported. Eighteen patients underwent the combined procedures between 1981 and 1988. Primary thrombectomy and balloon dilation were performed in 14 patients, and additional reconstruction was performed in three patients. The superficial femoral artery was the site of thrombectomy and dilation in 13 patients, and the external iliac artery was the site in the remaining five patients. Successful dilation was accomplished in all patients, with stenotic sites reduced below 30% by angiography, and ankle/brachial indexes increased by 0.15 or more. No operative deaths or complications occurred. Follow-up of superficial femoral artery dilations showed a 90% patency rate continued out to 4 years and a 40% patency rate at 5 years. Combined thrombectomy and interventional catheter therapy may aid in the care of this difficult to treat vascular patient group.

Management of arterial emboli: Gleanings from 20 years of experience

Arterial embolism is usually caused by cardiac disease, and atherosclerotic coronary vascular disease is the primary precursor. Other cardiac states, as well as several uncommon causes, are part of the etiologic spectrum. The earliest signs are pain, paresthesias, pallor, and pulselessness. Severe ischemia is indicated by paralysis, a late feature. Arterial embolism and acute thrombosis can be difficult to distinguish, and deep venous thrombosis may also be suspected in the differential diagnosis. To restore arterial flow, anticoagulation treatment with heparin (Lipo-Hepin, Liquaemin) is given and surgical embolectomy is performed. Heparin infusion is continued until the patient is ambulatory, and then warfarin sodium (Coumadin, Panwarfin) is given over the long term. Fibrinolysis has also been used to treat acute arterial occlusion. Complications of embolism must be carefully guarded against, and additional procedures are sometimes necessary.