Benjamin B. Chang

Resurrection of the in situ saphenous vein bypass. 1000 cases later.

Distal bypasses for the terminal stages of atherosclerotic occlusive disease manifest by chronic limb-threatening ischemia are among the most challenging arterial reconstructive procedures of surgeons today. The length and low flow rates of distal bypasses often exceed the functional limits of synthetic and even free vein grafts. However, the saphenous vein, when used in situ, provides a unique, viable, physiologically active, and hence antithrombogenic endothelial flow surface that is ideally suited for such bypasses. This paper presents the experience of the Albany Medical Center Hospital with the first 1000 in situ bypasses performed by the valve incision method over a 12-year period. Limb-threatening ischemia was the most common indication for surgery (91%). An in situ bypass was attempted in over 95% of unselected limbs and were completed in situ and in toto in 94%. 66% of the bypasses were carried out to the infrapopliteal level, and in more than 50% of the limbs, the distal vein diameter was <3.5 mm. The 30-day patency rate was 95%, and the cumulative patency rates, by life table analysis at 1, 2, 3, 4, and 5 years, were 90%, 86%, 84%, 80%, and 76%, respectively. The vein diameter, specific outflow vessel, level of distal anastomosis (length of bypass), inguinal inflow source used, and instrumental evolution had no significant effect on immediate or long-term bypass performance.

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.

Strategies to improve spinal cord ischemia in endovascular thoracic aortic repair: Outcomes of a prospective cerebrospinal fluid drainage protocol

PURPOSE Although endovascular repair of thoracic aortic aneurysm has been shown to reduce the morbidity and mortality rates, spinal cord ischemia remains a persistent problem. We evaluated our experience with spinal cord protective measures using a standardized cerebrospinal fluid (CSF) drainage protocol in patients undergoing endovascular thoracic aortic repair. METHODS From 2004 to 2006, 121 patients underwent elective (n = 52, 43%) and emergent (n = 69, 57%) endovascular thoracic aortic stent graft placement for thoracic aortic aneurysm (TAA) (n = 94, 78%), symptomatic penetrating ulceration (n = 11, 9%), pseudoaneurysms (n = 5, 4%) and traumatic aortic transactions (n = 11, 9%). In 2005, routine use of a CSF drainage protocol was established to minimize the risks of spinal cord ischemia. The CSF was actively drained to maintain pressures <15 mm Hg and the mean arterial blood pressures were maintained at >/=90 mm Hg. Data was prospectively collected in our vascular registry for elective and emergent endovascular thoracic aortic repair and the patients were divided into 2 groups (+CSF drainage protocol, -CSF drainage protocol). A chi(2) statistical analysis was performed and significance was assumed for P < .05. RESULTS Of the 121 patients with thoracic stent graft placement, the mean age was 72 years, 62 (51%) were male, and 56 (46%) underwent preoperative placement of a CSF drain, while 65 (54%) did not. Both groups had similar comorbidities of coronary artery disease (24 [43%] vs 27 [41%]), hypertension (44 [79%] vs 50 [77%]), chronic obstructive pulmonary disease (18 [32%] vs 22 [34%]), and chronic renal insufficiency (10 [17%] vs 12 [18%]). None of the patients with CSF drainage developed spinal cord ischemia (SCI), and 5 (8%) of the patients without CSF drainage developed SCI within 24 hours of endovascular repair (P< .05). All patients with clinical symptoms of SCI had CSF drain placement and augmentation of systemic blood pressures to >/=90 mm Hg, and 60% (3 of 5 patients) demonstrated marked clinical improvement. CONCLUSION Perioperative CSF drainage with augmentation of systemic blood pressures may have a beneficial role in reducing the risk of paraplegia in patients undergoing endovascular thoracic aortic stent graft placement. However, selective CSF drainage may offer the same benefit as mandatory drainage.

The anatomy of the greater saphenous venous system

To define surgical anatomy, a prospective study of the greater saphenous venous system in 385 instances in 331 patients was carried out with the use of prebypass phlebography (either pre- or intraoperative). The phlebographic interpretations were confirmed during the operative procedures and from the completion angiogram. These details were recorded and analyzed by a specific computer program. These data consisted of a number of superficial branches, perforators, the identification of valve leaflets, sinuses, and the size and position of the main venous trunk both in the thigh and in the calf. The study showed that a single trunk was present in the thigh in 65% of patients and in the calf in 45%. The remainder were variants of double systems. In two thirds of patients who had complete double systems, the larger system was used for in situ bypass but the rest required the use of parts of both systems. Phlebography was accurate in the depiction of the anatomic variations (93%), double systems, cross connections, and perforator branches (87%). However, the number of competent valves could not be accurately determined (accuracy, 68%). The diameter of the vein was frequently underestimated (in 80% by 1.1 +/- 0.4 mm) and hence could not be used as an index of vein adequacy. After phlebography, four patients had transient rises in serum creatinine levels and one had an iatrogenic thrombosis of a distal segment. This study suggests that the precise anatomy of the greater saphenous venous system should be determined preoperatively by phlebography since this information is valuable for proper surgical planning before vein is used as a graft or for in situ bypass in the lower extremity.

Carotid endarterectomy by eversion technique: its safety and durability.

SUMMARY BACKGROUND DATA The outcome of standard longitudinal carotid endarterectomy (CEA) can be measured by preservation of neurologic function with a low incidence of restenosis. Closure of the internal carotid arteriotomy with or without a patch may predispose to restenosis. Alternatively, transection of the internal carotid artery at the bulb with eversion endarterectomy allows expeditious removal of the plaque and direct visualization of the endpoint. Because the proximal internal carotid artery is anastomosed to the common carotid artery, this obviates the need for patch closure. The authors report their results with this technique in more than 2200 procedures. METHODS From May 1993 to March 1998, 1855 patients underwent 2249 CEAs using the eversion technique. During the same period, 410 patients had 474 CEAs by standard technique. Three hundred fifteen procedures in the eversion group and 65 procedures in the standard group were combined CEA and coronary artery bypass grafts. Most solo CEAs (97%) were performed in awake patients using regional anesthesia. Shunts were used on demand in 6% of CEAs. RESULTS The operative mortality rate was 1.02% (16/1575) in the solo eversion group and 2.2% (9/410) in the standard group. There were 18 permanent neurologic deficits (0.8%) in the eversion group and 11 (2.3%) in the standard group. Transient neurologic deficits occurred in 20 patients (0.9%) in the eversion group and 13 patients (2.7%) in the standard group. Of the 1855 patients, 1786 (96%) presented for duplex ultrasound follow-up. There were seven (0.3%) stenoses greater than 60% in the eversion group versus five (1.1%) in the standard group. CONCLUSIONS Eversion CEA can be performed safely with a low rate of stroke and death and a minimal restenosis rate in short- and long-term follow-up.

Fate of the excluded abdominal aortic aneurysm sac: Long-term follow-up of 831 patients

PURPOSE Nonresective treatment of the infrarenal abdominal aortic aneurysm by proximal and distal ligation of the aneurysm sac (exclusion) combined with aortic bypass has been previously reported. A 10-year experience with 831 patients undergoing this procedure was reviewed. METHODS From 1984 to 1994, 831 (761 elective, 70 urgent) of 1103 patients being treated for abdominal aortic aneurysm underwent repair with the retroperitoneal exclusion technique. Perioperative morbidity and mortality, estimated blood loss, transfusion requirements, natural history of the excluded aneurysm sac, and long-term survival were all assessed. RESULTS The operative mortality rate for patients undergoing exclusion and bypass was 3.4%. The incidence of nonfatal perioperative complications was 5.2%. Colon ischemia requiring resection occurred in 2 (0.2%) of the 831 patients. Estimated blood loss was 638 +/- 557 cc (50 to 330 cc). On follow-up 17 (2%) patients were found to have patent aneurysm sacs as detected by duplex examination. Fourteen patients required surgical intervention. No cases of graft infection or aortoenteric fistula have been noted. CONCLUSION Retroperitoneal exclusion and bypass is a viable alternative to traditional open endoaneurysmorraphy in surgery for abdominal aortic aneurysm. Most excluded aneurysm sacs have thrombosis without any long- or short-term complications; however, in a small number of patients delayed rupture of patent aneurysm occurs, thus emphasizing the need for diligent follow-up and appropriate intervention.

Is long vein bypass from groin to ankle a durable procedure? An analysis of a ten-year experience

Long vein bypass from the femoral artery to the level of the ankle may be performed with good initial success despite extreme bypass length and limited outflow tracts. However, the long-term performance of these bypasses remains to be defined. During the last 10 years we have performed single greater saphenous vein in situ bypass to the ankle level in 270 patients. There were 187 male and 83 female patients, and 61% of the patients were diabetic. The operative mortality rate was 3.7%. Cumulative bypass patency was 79% at 3 years and 73% at 5 years. In a similar manner, limb salvage was 93% at 3 years and 89% at 5 years. The patency rate was similar for various inflow arteries (common femoral, 88 cases; proximal superficial femoral, 135 cases; and deep femoral, 41 cases) and outflow tracts (dorsal pedal, 72 cases; anterior tibial, 59 cases; posterior tibial, 72 cases, and peroneal, 67 cases). Short bypasses, composite bypasses, free-vein grafts, and bypasses proximal to 10 cm above the ankle were excluded from this analysis. These data show that a long bypass to the ankle level for limb salvage is a durable procedure. The basic concept of bypassing all occlusive disease to the distal open artery in patients undergoing limb salvage should be an acceptable dictum. Excellent long-term patency and limb salvage rates are achievable by following this principle.

Treatment of abdominal aortic aneurysm by exclusion and bypass: An analysis of outcome

Abdominal aortic aneurysm is conventionally treated by aneurysmorrhaphy with inlying graft. Alternatively, division of the aorta, with suture closure of the distal aorta and outflow vessels (exclusion of the aneurysm), and end-to-end proximal to distal bypass may be performed. However, the long-term fate of this operation has not been determined. Specifically, concern exists that the excluded blood filled aneurysm may not thrombose or may be the source of late sepsis. During an 8-year period we have treated 280 abdominal aortic aneurysms (urgent and elective) by exclusion of the abdominal aortic aneurysm sac and bypass via the posterolateral retroperitoneal approach. Mean age was 70 years (range, 44 to 88), with 217 men and 63 women. Preoperative CT scanning and aortography were performed to assess arterial anatomy. Seventy tube grafts and 260 bifurcation grafts were used. Thirty-day mortality rate was 4%. Estimated blood loss was 731 +/- 52 ml; mean transfusion requirements were 456 +/- 82 ml. The minor complication rate was 6%, and it is of great interest that there were no cases of ischemic colitis requiring colectomy. Aneurysm sacs thrombosed except in two anticoagulated patients who required further treatment. No late infections occurred. Five-year bypass patency rate was 98%. These data demonstrate that this method of treatment effectively minimized operative dissection and blood loss and therefore is a viable alternative for the management of abdominal aortic aneurysms.

The incidence, natural history, and outcome of secondary intervention for persistent collateral flow in the excluded abdominal aortic aneurysm

OBJECTIVE The goal of abdominal aortic aneurysm (AAA) repair is the prevention of rupture. Exclusion of the infrarenal AAA by means of operation or endovascular graft placement is an alternative therapy to achieve this goal. However, thrombosis of the excluded aneurysm sac does not always occur and further intervention may be needed. This study examines the efficacy of available screening methods to detect the persistence of aneurysm sac flow and the outcome of secondary procedures to treat this problem. METHODS During the past 14 years, 1218 patients have undergone operative retroperitoneal exclusion of AAA. To date, 48 patients have been found to have persistent flow in the excluded AAA sac with duplex scanning. Twenty-seven patients underwent surgical intervention, and seven of these procedures were performed for rupture. Six patients have undergone treatment with interventional techniques (four successfully). The patients were evaluated for preoperative angiographic, anatomic, and comorbid factors that may have predisposed them to failed exclusion. Also, perioperative morbidity and mortality, estimated blood loss, and survival were assessed in the patients who required surgical treatment. RESULTS There were no perioperative parameters that correlated with postoperative persistent flow in the excluded AAA sac. The mean time to secondary intervention was 51 months (range, 2 to 113 months). Two patients had false-negative computed tomographic angiogram results, eight patients had false-negative angiogram results, and six patients had duplex scan examinations that had initially negative results that were then positive for flow in sac. Reoperation had a 7.4% mortality rate (two deaths) and a median blood loss of 2600 mL, as compared with 500 mL for primary procedures. CONCLUSION Secondary operations for patent excluded aortic aneurysm sacs have higher mortality and intraoperative blood loss rates than do primary procedures for AAA repair. The localization of branch leaks with computerized tomographic angiography, angiography, and duplex scanning were imprecise, and better methods are needed to adequately diagnose patent sacs. Expansion of AAA sac may be the only reliable factor.

Durability of the tibial artery bypass in diabetic patients

Infrapopliteal bypass in diabetic patients has been associated with lower rates of patency and limb salvage than in nondiabetic patients. We prospectively compared the patency and limb salvage rates of in situ tibial artery bypass in diabetic and nondiabetic patients. Of 681 in situ bypasses performed for limb salvage over a 7 year period, 387 (57 percent) were carried out in diabetic patients and 294 (43 percent), in nondiabetic patients. Indications for operation most commonly included gangrene or ulceration (74 percent of the diabetic group and 49 percent of the nondiabetic group). Otherwise, the two patient groups were similar. Cumulative patency rates at 1 and 5 years were similar (91 and 74 percent for diabetic patients and 90 and 76 percent for nondiabetic patients, respectively). Limb salvage rates were also not significantly different (96 and 86 percent at 1 and 5 years, respectively, for diabetic patients and 99 and 94 percent, respectively for nondiabetic patients). Despite the unfavorable pattern of atherosclerosis in diabetic patients, the results of tibial arterial reconstructions showed patency and limb salvage rates similar to those seen in nondiabetic patients.