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Biomedical subjects

B B Chang

Publications and source records attributed to B B Chang.

At least 73 records · Page 4Linked to original sources
PubMed1994

Retroperitoneal approach for bilateral renal and visceral artery revascularization.

Revascularization for renal and visceral arterial occlusive disease has traditionally been performed via a transperitoneal approach. Exposing these arteries transperitoneally is often difficult, however, and may require extensive medial visceral rotation. An alternative is a left retroperitoneal approach for renal and visceral arterial revascularization, including procedures involving the right renal artery. Over the past 7 years, a total of 186 such procedures have been performed using this approach. Of 30 that involved primarily the celiac and mesenteric arteries, 20 were completed with a bypass graft and 10 with transaortic endarterectomy. Of 156 procedures performed for renal arterial occlusive disease or aneurysmal disease extending above the renal arteries, 32 were treated with transluminal endarterectomy, 21 were treated with bilateral bypasses, and 72 were treated with unilateral bypass. Concomitant aortic endarterectomy or graft replacement was performed in 110 of this group. Operative mortality was 3.3%. Reconstructions were followed-up (for 1 to 76 months) with serial duplex and renal flow ultrasonography scans. One thrombosis developed in a renal artery bypass. We conclude that the left retroperitoneal approach may conveniently be used to reconstruct the celiac artery, superior mesenteric artery, and both renal arteries. These reconstructions may be performed with either an endarterectomy or bypass technique. In particular, the need to revascularize the right renal artery should not be regarded as a contraindication to using a left retroperitoneal approach.

Adolescent↗
PubMed1994

Increased limb salvage by the use of unconventional foot amputations.

PURPOSE: Limb salvage in the presence of ischemic foot necrosis requires revascularization followed by debridement or partial foot amputation. Necrosis extending beyond the toes and metatarsal heads may require the use of unconventional types of amputations. METHODS: Over a 15-year period 2105 ischemic limbs were treated with infrainguinal revascularization. In 98 cases, extensive foot necrosis was than managed with amputations, including 59 modified Chopart, 14 Lisfranc, 17 Pirogoff and 8 Syme amputations. Patients were not allowed to bear weight for several days to weeks. RESULTS: Skin flap necrosis in 14 cases was managed successfully by debridement and skin grafting. Ambulation required the use of a "clamshell" prosthesis and foot spacer. The overall limb salvage rate in this group was 84% (82 of 98). In general, the modified Chopart amputation most frequently produced ambulatory limb salvage and is technically easier to perform than a Syme amputation. Patient satisfaction and long-term ambulatory function was highest with the modified Chopart. CONCLUSION: Ischemic foot necrosis extending beyond the limits of conventional transmetatarsal amputation need not be treated with major amputation. This requires the surgeon to be well versed in the use of less common types of partial foot amputations. Acceptable limb salvage and good functional results may be attained by the motivated patient and surgeon with the use of these procedures in the revascularized limb.

Activities of Daily Living↗
PubMed1994

Carotid endarterectomy in awake patients: its safety, acceptability, and outcome.

PURPOSE: The purpose of this study was to determine the safety and efficacy of performing carotid endarterectomy procedures with the patient receiving cervical block anesthetic. METHODS: Over the last 14 years, 654 carotid endarterectomy procedures were performed with patients receiving regional anesthetic. Intraluminal shunts were placed on demand, if neurologic changes with clamping of the carotid artery developed in the patient. During the same period, 419 cases were done with the patients receiving general anesthetic. Choice of anesthetic was based on surgeon and patient preference. RESULTS: In the regional anesthetic group the indications for operation included transient ischemic attack (311), asymptomatic hemodynamically significant stenosis (146), amaurosis fugax (106), stroke (86), restenosis (3), and aneurysm (2). Shunts were used in 46 of 654 cases (7%). Conversion from regional to general anesthetic was required in seven patients (1.1%). The operative mortality rate was 0.76% (5 of 654). Permanent nonfatal neurologic deficits occurred in 0.76% (5 of 654), and temporary neurologic deficits occurred in 1.07% (7 of 654). CONCLUSIONS: On the basis of these results, we believe regional cervical block anesthetic is an acceptable option to the routine use of shunts performed with the patient receiving general anesthetic during carotid endarterectomy. In addition, the ability to continuously assess the awake patient receiving cervical block may contribute to a decrease in perioperative stroke and mortality rates while simplifying functional cerebral monitoring during carotid endarterectomy.

Adult↗
PubMed1993

Aortic replacement for abdominal aortic aneurysm in elderly patients.

Improvements in the operative mortality and morbidity rates in elective aortic replacement, which are largely a result of refinements in surgical technique and perioperative management, have allowed a more aggressive approach in the treatment of abdominal aortic aneurysm (AAA) in elderly patients. To evaluate this approach, we reviewed the records of 116 patients 80 years of age and older (range: 80 to 93 years) who consecutively underwent aortic replacement for AAA. Seventy-seven patients underwent elective aortic replacement with 8 complications and a 3% operative mortality rate (2 of 77). Emergent aortic replacement was performed in 39 patients (14 with symptomatic nonruptured AAA and 25 with ruptured AAA) with 12 complications. In this nonselective subset, there were eight deaths, for an operative mortality rate of 20% (symptomatic 14%, ruptured 24%). In comparison, 780 patients less than 80 years of age underwent aortic replacement during the same time period. Within this group, 622 patients who were treated on an elective basis had a similar operative mortality (2%) as did patients 80 years of age and older. On the basis of these results, we believe that elective aortic replacement in elderly patients is justified and can be achieved with low operative mortality and morbidity rates. We suggest that the chronologic age of the patient should not deter aortic replacement.

Aged↗
PubMed1993

Is the iliac artery a suitable inflow conduit for iliofemoral occlusive disease: an analysis of 514 aortoiliac reconstructions.

PURPOSE: The aorta is the conventional inflow source for reconstructions in patients with aortoiliofemoral occlusive disease. In patients with unilateral iliac or femoral disease, femoral-to-femoral bypasses have been used but with less favorable patency rates. The purpose of this study is to evaluate the performance of the unobstructed iliac artery as an inflow source for ipsilateral, contralateral, or bilateral reconstructions in iliofemoral occlusive disease. METHODS: Over the past 6 years 322 reconstructions have been performed with the iliac artery as the donor vessel. Patients were evaluated for proximal hemodynamically significant lesions by augmented pullout pressures during aortography. Patients who had balloon angioplasty were excluded. RESULTS: Results were compared with 192 patients who underwent conventional aortodistal bypass operation for occlusive disease during the same period. Both groups were similar in risk factors, age, sex, and indications for operation. For the iliac group the operative mortality rate was 1.6%, and the 30-day patency rate was 97%, similar to those in the aortic group (3.6% and 95%, respectively). Cumulative patency rates at 5 years by life-table analysis were 82% for iliac artery inflow and 77% for aortic inflow reconstructions. CONCLUSIONS: Our experience suggests that an unobstructed iliac artery is a reasonable inflow source for reconstructions in iliofemoral occlusive disease. The long-term patency rate is comparable to aortodistal bypasses and superior to other extraanatomic bypasses.

Aorta, Abdominal↗
PubMed1993

Outcome following blunt vascular trauma of the upper extremity.

Blunt trauma to the upper extremity may cause extensive vascular damage in addition to severe musculoskeletal injury. Over a 5.5-year period, 17 patients with a total of 23 arterial injuries were treated. Diagnosis was made in 16 patients before surgery by physical and Doppler ultrasonographic examination. Angiography performed in ten patients assessed the extent of injury. Associated orthopedic injuries were present in 11 patients and neurologic injury in 16. At surgery, 21 of 23 arterial repairs required autologous vein. The initial limb salvage rate was 76%. Four patients underwent above-elbow amputation because of progressive sepsis and myonecrosis. A fifth underwent delayed amputation at 7 months due to loss of limb function. Neurologic impairment was the major long-term morbidity. The data show that outcome following blunt vascular trauma of the upper extremity is governed by the associated injuries.

Adolescent↗
PubMed1993

Alternative conduits for coronary revascularization: a novel approach for harvest of the lesser saphenous vein.

Previous use of the greater saphenous vein limits the subsequent availability of conduit for coronary artery bypass grafting (CABG). One readily available alternative conduit is the lesser saphenous vein (LSV). During a 4-year period, 34 LSVs were explored in 23 patients using a novel surgical approach. The incision used for LSV harvest was carried through and deep into the muscular fascia, posterior to the tibia, along the length of the leg, developing a fascial-cutaneous flap. The LSV in all patients was imaged before operation by venous duplex scanning. Important anatomic details were mapped on the patient's leg before surgery using indelible ink. Findings at operation correlated well with the duplex imaging results. Of the 34 LSVs explored 31 were judged usable by the operating surgeon. In eight patients bilateral LSVs were used and in two this vein was the only conduit available. Among patients undergoing LSV harvest there was no operative mortality and minimal operative morbidity related to harvesting. Only one wound infection developed at the incision site. There were no documented cases of deep vein thrombosis. A case-control study was performed in which a control group of 25 patients undergoing CABG without use of the LSV were compared with the 23 who had LSVs harvested; patients in both groups underwent preoperative venous duplex studies. There were no significant differences in operative mortality or morbidity rate between groups (statistical power > 0.8 for these negative observations), suggesting that harvest of the LSV is usually successful when used in conjunction with preoperative venous duplex scanning.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Ultrasonic characterization of the saphenous vein.

The most frequently used conduit for infrainguinal or coronary artery bypass is the saphenous vein, and this report describes the ultrasonic evaluation of anatomic variations in over 1400 limbs. The thigh portion of the greater saphenous vein consisted of a single venous conduit in 67% of the limbs, a complete double system in 8%, a branching double system in 18% and a closed loop double system in 7%. In 92% of the cases, the vein was in medial position, with the remaining 8% positioned laterally. In the calf, a single vein was observed in 65% of the limbs with the remainder demonstrating a double venous system. The vein was positioned anteriorly in 85% of the limbs. The remaining 15% were positioned posteriorly, with 7% of these being a single dominant vein. Proper knowledge of saphenous vein anatomy is vital to the surgeon preparing to use this vein as a bypass conduit and can aid in its preoperative assessment.

Arteriosclerosis↗
PubMed1993

Treatment of the diabetic foot from a vascular surgeon's viewpoint.

Diabetic foot lesions are caused by neurologic, orthopaedic, immunologic, and vascular derangements. Whereas some lesions may be initially caused by trauma and others directly caused by vascular disease, improvement of arterial perfusion often plays an important role in the successful salvage of these limbs. Fortunately, in the last several years, there has been a major improvement in the identification and treatment of those patients in whom correction of arterial occlusive disease is necessary for healing.

Angiography↗
PubMed1993

Optimal outcome after tibial arterial bypass.

To evaluate factors for the optimal outcome after tibial arterial bypass for lower extremity ischemia, we analyzed our experience with 1,359 such bypasses during the last ten years. There were 869 males and 490 females, of whom 739 patients (54 percent) had diabetes. The average age was 68 years. One thousand and twenty-four bypasses were performed using the atraumatic valve incision in situ technique, 281 bypasses using free vein grafts and 54 bypasses with synthetic materials. These bypasses were taken to the anterior tibial (312 patients), posterior tibial (341 patients), peroneal (520 patients) and dorsalis pedis arteries (125 patients). Inflow arteries included external iliac (two patients), common (435 patients), superficial (472 patients) and profunda femoris arteries (259 patients). In certain instances, popliteal and tibial arteries were used for inflow (short bypasses). Limb salvage was the significant indication (95 percent). The overall cumulative primary patency rate at five years was 68 percent and secondary patency was 76 percent. In situ bypasses had the best secondary patency rate of 80 percent at five years followed by free vein grafts of 70 percent and synthetic bypasses of 33 percent. The choice of inflow or outflow arteries did not influence the patency rate in any category. The overall limb salvage rate was 94 percent at five years. Short bypasses using free vein grafts had a similar patency to long free vein graft but lower patency than long in situ bypasses. These data demonstrate that bypasses to tibial arteries, using autogenous vein for ischemia of the lower extremity and limb salvage, have long term durability. In situ bypass with a complete saphenous vein is the best conduit for such reconstructions. We suggest that tibial arterial bypass should be strongly considered in all instances for limb salvage when autogenous vein is available before resorting to primary amputation.

Aged↗
PubMed1992

Long-term follow-up of poor-risk patients undergoing small-diameter portacaval shunts.

The small-diameter portacaval H-graft has been shown to be a reliable method of controlling variceal hemorrhage. However, little has been written about the long-term follow-up of poor-risk patients treated by this method. Over the last 11 years, we have performed 38 portacaval H-grafts; 79% of the patients were Child's B or C, and 79% were alcoholic. The mean age was 52 years, and the mean period of follow-up was 44 months. Over 37% of the grafts were performed in patients who were bleeding at the time of operation. Our 30-day operative mortality was 13%. Postoperatively, the small-diameter H-graft was associated with mild to moderate encephalopathy in 33% of the patients and ascites in 42%. Both these conditions were easily controlled with diet and medication. Early recurrent variceal bleeding was seen in 13% of patients. However, on late follow-up, recurrent hemorrhage and encephalopathy have been seen in only 12% and 14% of patients, respectively. We conclude that the portacaval H-graft is a reliable and lasting method for controlling variceal bleeding with an acceptable postoperative morbidity and mortality.

Adolescent↗
PubMed1992

Adventitial cystic disease of the femoral vein: a case report and review of the literature.

Painless edema of the left leg developed in a 65-year-old man without a history of venous disease, and he was found to have a mass compressing the lumen of the left common femoral vein. The intramural cyst was drained through transvenous exposure and found to contain mucoid material. This is the seventh case of adventitial cystic disease of a vein in the world literature. Analogous to adventitial cystic disease of arteries, it is defined by venography, CT scanning, and duplex ultrasonography. Surgical drainage is the treatment of choice.

Aged↗
PubMed1992

The lesser saphenous vein: an underappreciated source of autogenous vein.

Use of the ipsilateral greater saphenous vein for arterial bypass procedures is frequently limited by previous stripping, bypass operations, or anatomic unsuitability. In such cases the contralateral greater saphenous vein or arm veins are often used. However, over the past 5 years we have used the lesser saphenous vein as a preferred alternative autogenous vein. Duplex scanning has been used in 311 cases for preoperative mapping and assessment with excellent correlation with actual anatomy found at operation. Harvest of the lesser saphenous vein has been facilitated by the use of a medial subfascial approach not requiring special positioning of the leg. A total of 91 lesser saphenous veins have been used for arterial bypass procedures; 66 of these were repeat cases. Vein use was 90.2%. In 40 of these cases the lesser saphenous vein was used as the entire conduit, including 10 in situ, 20 reversed vein (including 18 for coronary artery bypass), and 10 orthograde vein bypasses. In the remaining 33 cases the lesser saphenous vein was spliced to another vein to complete a bypass procedure. In the entire group, patency was 77% at 2 years. These data suggest that the lesser saphenous vein should be a principal alternative to ipsilateral greater saphenous vein for arterial bypass because of its ready availability, high use rate, ease of harvesting and preparation, and ideal handling characteristics.

Adult↗
PubMed1992

Retroperitoneal in-line aortic bypass for treatment of infected infrarenal aortic grafts.

Since 1970, we have treated 43 patients with infected aortic grafts. Early in the series, four patients were treated with resection of the fistula or erosion and systemic and topical antibiotics without removal of the graft. All four patients died. Thirty-two patients were treated by conventional therapy; there were 13 deaths (40 percent). More recently, seven patients were managed by the left retroperitoneal placement of a new in-line polytetrafluoroethylene (PTFE) aortic graft through clean tissue planes, followed by the immediate transperitoneal removal of the infected graft without cross-contamination. Patients were maintained postoperatively on antibiotics for a minimum of two weeks. All seven patients survived without septic complications, with a mean follow-up time of 36 months (six months to four years). The surgical technique consists of initial suprarenal control of the aorta, followed by infrarenal division and oversewing of the distal aorta. A PTFE bifurcation graft is placed connecting the proximal aorta and the appropriate femoral vessels, the right limb tunneled through the space of Retzius. After closure of the incisions, through the space of Retzius. After closure of the incisions, the patient is placed in the supine position and the infected graft is removed transperitoneally. We believe that retroperitoneal in-line aortic bypass for treatment of an infected aortic graft offers a favorable alternative to conventional therapy by avoiding the use of an extra-anatomic bypass and associated risk of stump blowout.

Anti-Bacterial Agents↗