Subclavian revascularization. A quarter century experience.

OBJECTIVE: Twenty-five years of experience with subclavian revascularizations were reviewed to determine the long-term patency rates of different extrathoracic approaches. SUMMARY BACKGROUND DATA: Although it is generally agreed that proximal subclavian stenosis should be treated by an extrathoracic route whenever possible, the optimum procedure is debated. Alternatives include subclavian carotid bypass, subclavian-to-subclavian or axillo-axillary bypasses, and the authors' preferred technique of subclavian carotid transposition (SCT). METHODS: Records were researched for the past 25 years in a single specialty surgical clinic for extrathoracic subclavian revascularizations. One hundred ninety such procedures were identified, and hospital charts and office medical records were reviewed for procedure, preoperative symptoms, blood pressure differentials, and postoperative complications. Patency was determined by physical examination, differential blood pressures, Doppler spectral analysis, duplex examinations, and arteriography. RESULTS: Bypass procedures were used infrequently, and although the results are reported, they are excluded from any analysis. Subclavian carotid transposition was used in 178 procedures. All anastomoses were found to be patient at follow-up, except for one, which failed at 26 months. Mean follow-up was 46 months, with five patients lost to follow-up. Overall mortality rate was 2.2%, with the mortality falling to 1.1% if only subclavian carotid transposition patients are included. CONCLUSIONS: Subclavian carotid transposition should be the treatment of choice for routine subclavian carotid occlusive disease because of its exceptional long-term patency and low morbidity.

Recurrent aortic occlusion.

In a review of 134 aortic occlusions in 123 patients, there were 10 patients that suffered recurrent aortic occlusions (RAO). These patients developed RAO after revascularization for primary aortic occlusion and presented with signs and symptoms of acute lower extremity ischemia. The recurrent occlusions occurred in one native aorta and in 10 aortobifemoral grafts. The etiology of the primary aortic occlusion included chronic aortic occlusion in eight patients and acute aortic occlusion and aortic graft occlusion in one patient each. Original primary operations performed included aortoiliac thromboendarterectomy with Dacron patch aortoplasty (1 patient), AF bypass (8 patients), and aortofemoral graft thrombectomy (1 patient). All of the grafts had end-to-end proximal anastomoses, the diameter of which ranged from 12 to 16 mm. Secondary operations performed for RAO included six axillofemoral bypasses, four redo aortobifemoral bypasses, and one graft thrombectomy. All patients were managed with immediate anticoagulation, expeditious arteriography, and revascularization. There were no perioperative deaths, and no limbs were lost. No patient was lost to follow-up (mean 10 years). Extra-anatomic bypass has proved durable. Redo aortobifemoral bypass is useful in selected patients with surgically correctable lesions.

Multi-branch renal artery lesions: surgical options and results.

Renovascular lesions affecting more than one primary or secondary renal artery branch represent a challenging therapeutic problem. Over the last 5 years, the authors have treated 20 patients with complex multi-branch renal lesions. The number of renal artery branches per kidney ranged from two to seven. The pathological etiology of the multi-branch lesion was atherosclerotic occlusive disease in ten patients, fibromuscular occlusive disease in four (two with spontaneous dissection), renal artery aneurysm in three and abdominal aortic coarctation in three. Ex vivo techniques were used in nine patients, whereas in situ reconstruction was used in 11. Ten patients had a complex procedure involving aortic or other visceral reconstruction; two patients had solitary kidneys. There was one death in the series from an intraoperative anesthetic complication. One primary nephrectomy was performed after ex vivo exploration revealed unreconstructable disease in a significant number of branches. Severe hypertension present in all the patients before surgery was cured in five patients and improved in 14 after the operation. Renal insufficiency, present in nine patients before surgery, was improved in all cases.

Suprarenal aortic occlusion.

PURPOSE: This report was designed to elucidate the clinical manifestations of suprarenal aortic occlusion (SRAO) and determine the efficacy of surgical treatment. METHODS: A retrospective review of 135 patients with aortic occlusion was undertaken from which the 16 patients (12%) with SRAO were found. RESULTS: Analysis yielded two subsets of patients based on the time-frame over which SRAO developed. Group I (n = 13) had chronic aortic occlusion with proximal propagation of thrombus to involve the suprarenal aorta. They had uncontrolled hypertension and claudication. Surgical treatment included 16 renal reconstructions (nine patients), two nephrectomies, 10 aortobifemoral bypasses, and three extra-anatomic procedures. The operative mortality rate was 23%. In contrast, group II (n = 3) had acute SRAO, manifest by profound lower extremity ischemia and acute renal failure after cardiac dysrhythmias. Two patients were moribund and died shortly after extraanatomic "salvage" procedures. One patient survived aortobifemoral and bilateral renal artery bypass. CONCLUSION: Chronic SRAO should be suspected in patients with absent femoral pulses and refractory hypertension. Aortic and renal reconstruction offers long-term improvement in hypertension control and relief of claudication. Acute SRAO is a multisystem disorder that is ineffectively managed with extraanatomic "salvage" procedures.

Juxtarenal aortic occlusion.

The authors' experience with 113 aortic occlusions in 103 patients during a 26-year period (1965 to 1991) is reviewed. The authors found three distinct patterns of presentation: group I (n = 26) presented with acute aortic occlusion, group II (n = 66) presented with chronic aortic occlusion, and group III (n = 21) presented with complete occlusion of an aortic graft. Perioperative mortality rates were 31%, 9%, and 4.7% for each respective group and achieved statistical significance when comparing group I with group II (p = 0.009) and group I with group III (p = 0.015). Group I presented with profound metabolic insults due to acute ischemia and fared poorly. Group II presented with chronic claudication and did well long-term. Group III presented with acute ischemia but did well because of established collateral circulation. The treatment and expected outcome of aortic occlusion depends on the cause.

Ruptured abdominal aortic aneurysm and horseshoe kidney.

We have described three patients surviving resection of a ruptured abdominal aortic aneurysm in the presence of horseshoe kidney. If division of the renal isthmus is required to gain rapid control of the ruptured abdominal aortic aneurysm, it is not necessarily associated with increased morbidity or mortality. The arterial supply to the horseshoe kidney may complicate arterial reconstruction, but with flexible use of modern vascular surgical techniques, preservation of renal tissue is feasible.

Effect of chronic cold and submergence on blood oxygen transport in the turtle, Chrysemys picta.

Whole blood oxygen equilibrium curves (O2EC's) and related hematologic properties are reported for the turtle Chrysemys picta exposed to two experimental conditions. Summer turtles were maintained at 24 degrees C with free access to air; winter turtles were submerged for 4-12 wk in N2-bubbled water at 3 degrees C. Half-saturation Po2's at 3 degrees C for blood from summer and winter animals were 4.1 and 4.5 Torr, respectively. At 24 degrees C, summer and winter P50's were 20.2 and 22.7 Torr, respectively. The winter turtle P50 values were lower than predicted since prolonged submergence effected a severe metabolic acidosis; blood pH's for winter turtles were 0.65 pH unit lower than for summer animals at both temperatures. Cold submergence also had a profound influence on O2EC shape. Winter turtle curves exhibited high O2 affinity below P50 while they were distinctly right-shifted above 50% S. Winter animals also exhibited reduced CO2-Bohr coefficients (delta log Po2/delta pH) at 3 and 24 degrees C. Prolonged submergence did not affect the animal's isohemoglobin profile (demonstrated by isoelectric focusing) or [metHb]. The [ATP] and [DPG] in winter turtle red cells, however, decreased significantly; the ratio of organic phosphate ([ATP] + [DPG]) to Hb tetramer fell from 1.4 in summer animals to 0.5 in winter turtles. These findings suggest that the effect of chronic cold and prolonged submergence on turtle O2EC position and shape may result from reduction in RBC organic phosphates. Furthermore, these observed changes in blood oxygen transport may facilitate O2 loading during winter submergence via extrapulmonary gas exchange.