Neutrophil leukotriene generation and pulmonary dysfunction after abdominal aortic aneurysm repair.

BACKGROUND: The purpose of this study was to assess the role of polymorphonuclear neutrophil (PMN)-generated leukotriene B4 (LTB4) as an etiologic agent in the pulmonary dysfunction seen after operation in patients undergoing abdominal aortic aneurysm repair. METHODS: Blood was analyzed in 10 consecutive patients undergoing elective infrarenal abdominal aortic aneurysm repair for plasma thromboxane B2, lactoferrin, C3a, and PMN-generated LTB4. RESULTS: There was a close linear correlation (r = 0.88; p < 0.001) between aortic clamp time and PMN LTB4 production. Conversely, aortic clamp time and the ratio of arterial oxygen pressure to fraction of inspired oxygen, a measure of pulmonary function, were inversely related (r = -0.80; p < 0.008). PMNs from patients with long aortic cross-clamp times generated three times more LTB4 than those patients with short cross-clamp times (194 +/- 29.6 vs 64.9 +/- 9.7 ng per 5 x 10(6) PMN; p < 0.05). Similarly, the pressure/inspired oxygen ratio was significantly lower on admission to the intensive care unit in patients with long cross-clamp times as compared with patients with short cross-clamp times (237 +/- 14 vs 342 +/- 5; p < 0.005). In addition, patients with long cross-clamp times remained intubated longer than patients with short times (1.6 +/- 0.2 vs 0.6 +/- 0.4 days; p < 0.05). CONCLUSIONS: These data suggest a causal role for LTB4 in the generation of pulmonary dysfunction in patients undergoing abdominal aortic aneurysm repair, similar to what has been shown in animal models.

Management of renovascular problems during aortic operations.

Sixty patients who had primary aortic disease (aortic stenosis or aneurysm) and required simultaneous aortic and renal artery operations were divided according to the indications for renal artery repair as follows: group 1, renovascular hypertension (ten patients); group 2, kidney salvage (11 patients); group 3, improvement of renal function (three patients); and group 4, renal artery involvement in the diseased aorta (36 patients). Renal artery reimplantation and aortorenal grafting were usually employed. Two kidneys in the renal salvage group failed, and two main and three accessory arteries were found to be occluded on late follow-up. Three patients died after emergency surgery for aneurysm rupture (two patients) and infected false aneurysm (one patient). The mortality rate for combined operations is higher (5%) than for aortic or renal surgery alone, but simultaneous repair may be needed for technical reasons, or to treat renovascular disease.

Ex vivo renal artery reconstruction.

Twenty-four patients underwent ex vivo renal artery reconstruction of 26 extensive lesions using continuous hypothermic perfusion and replacement of the diseased renal artery with a hypogastric artery autograft. Postoperative acute tubular necrosis was avoided in these repaired kidneys. There was one postoperative graft occlusion accounting for the only failure in the series. Of the hypertensive patients, 95% were cured or improved during the follow-up period extending from six months to six years. Six of these patients have been followed more than three years and late postoperative arteriograms showed no alteration in their autografts. This method, therefore, extends the potential for renal artery reconstruction to most renal vascular lesions, reserving nephrectomy for the infarcted or severely atrophic kidney only.

The current role of renal angioplasty in the treatment of renovascular hypertension.

Percutaneous transluminal renal angioplasty, a relatively noninvasive technique, has assumed an increasing role in the treatment of renovascular hypertension. The combined advent of digital subtraction angiography, renal-vein renin samples, and percutaneous transluminal angioplasty have prompted many physicians to reassess their treatment strategies. The authors present their experience with renal angioplasty at the New York Hospital and briefly describe the history and mechanism of action of this procedure.

Necrotizing enterocolitis after cardiac surgery: a local ischemic lesion?.

Necrotizing enterocolitis continues to be a perplexing problem in the newborn and, in particular, the premature. Its pathogenesis is controversial, although there are well established clinical risk factors. Three patients had necrotizing enterocolitis while under close clinical observation and monitoring, despite the fact that these patients were not at high risk for necrotizing enterocolitis. All three had necrotizing enterocolitis after hypothermia and total circulatory arrest--a complication which until now has not been reported. Because of the close monitoring, these patients provide a unique clinical setting which eliminates most of the etiologic factors that have been implicated in the pathogenesis of necrotizing enterocolitis. The onset of necrotizing enterocolitis shortly after total circulatory arrest and the selective ischemic organ damage observed suggest local perfusion inadequacy. The authors postulate that splanchnic vasoconstriction as a result of marked sympathetic stimulation contributes to this local ischemia and subsequent necrotizing enterocolitis.

Pseudoaneurysm of the popliteal artery with an unusual arteriographic presentation. A case report.

Pseudoaneurysms caused by osteochondromas during the second decade of life are well known. Arteriography is generally helpful in the diagnosis of a false aneurysm. In a 30-year-old man, the case was unique in that the arteriogram failed to show the aneurysm at all. Physical examination revealed yellow discoloration and tiny hemangiomas of the skin over the fossa poplitea. More emphasis should be placed on the physical examination and less on the arteriogram in making a correct diagnosis.

Thrombosis of axillary-femoral bypass secondary to prosthesis suspension belt.

Patients with peripheral vascular disease and lower extremity amputation frequently undergo arterial bypass surgery to salvage the opposite leg. Compression of axillary-femoral bypass grafts can occur from a variety of causes. The primary physician should monitor graft pulses closely. Compression should be avoided by using forearm crutches instead of axillary crutches. Waist belts for prosthetic support should not be used, and alternatives such as a thigh corset or shoulder suspension should be used. The patient should avoid sleeping on the graft, using a wrist restraint when necessary. If the patient gains weight, garments should be adjusted so as not to be constricting. Upper extremity exercises, particularly in should abduction and extension, should not be so vigorous as to put tension on the graft. A 77-year-old woman with a left below-knee amputation underwent an axillary-femoral bypass for right lower extremity arterial insufficiency which subsequently thrombosed due to compression by the waist belt of her below-knee prosthesis. A series of guidelines are outlined, so that the physiatrist can help maintain graft patency, prolong limb salvage, and avert similar complications in such patients.

Two cases of spontaneous lysis of arterial thrombi.

Two cases of spontaneous lysis of arterial thrombi are described. The occurrence of spontaneous thrombolysis and the relative ease of performing Fogarty embolectomy (thrombectomy) in peripheral arteries should be considered along with the clinical status of a patient who is viewed as a possible candidate for thrombolytic therapy, a procedure which has a potential for severe hemorrhagic complications.

Hypothermia during elective abdominal aortic aneurysm repair: the high price of avoidable morbidity.

PURPOSE: Adverse outcomes apparently associated with hypothermia led us to examine patients undergoing elective abdominal aortic aneurysm (AAA) repairs to test the hypothesis that hypothermia (temperature less than 34.5 degrees C) is associated with increased morbidity and excess mortality rates. METHODS: Two hundred sixty-two elective AAA repairs were retrospectively reviewed for preoperative and intraoperative risk factors. Core temperature, age, Acute Physiology and Chronic Health Evaluation (APACHE) II and APACHE III scores (raw and temperature-adjusted), fluid resuscitation, and perioperative organ dysfunction were recorded prospectively. Outcome measures included lengths of stay in the intensive care unit and in the hospital, and hospital mortality rates. RESULTS: Except for a higher risk of hypothermia in women (p < 0.05), by univariate analysis, preoperative risk factors were similar in patients in the hypothermic and normothermic groups. After operation, patients with hypothermia had significantly greater APACHE scores (p < 0.0001), and patients in the hypothermic nonsurvivor group took significantly longer to rewarm (p < 0.05), suggesting marked hypoperfusion. Patients with hypothermia had significantly greater fluid (p < 0.05), transfusion (p < 0.01), vasopressor (p < 0.05), and inotrope (p < 0.05) requirements, resulting in significantly higher incidences of organ dysfunction (53.0% vs 28.7%, p < 0.01) and death (12.1% vs 1.5%, p < 0.01) and markedly prolonged lengths of stay in the unit (9.2 +/- 2.0 vs 5.3 +/- 0.6, p < 0.05) and in the hospital (24.3 +/- 2.9 vs 15.0 +/- 0.08, p < 0.01). By multivariate analysis, female gender (p = 0.004) was the only predictor of intraoperative hypothermia, whereas initial hypothermia was significantly predictive of both prolonged hypothermia and development of organ failure (p < 0.05). Organ failure (p < 0.05) and acute myocardial infarction (p < 0.01) were independent predictors of death. CONCLUSIONS: After AAA repair, patients with hypothermia have multiple physiologic derangements associated with adverse outcomes. Although multiple etiologic factors are interacting, body temperature is one variable that should be controlled during aortic surgery.

Recurrent pulmonary oedema in hypertension due to bilateral renal artery stenosis: treatment by angioplasty or surgical revascularisation.

11 patients with atheromatous renovascular hypertension had a history of multiple episodes of pulmonary oedema. 7 had stenosis of both renal arteries, 2 had stenosis of the artery to a solitary kidney, and 2 had unilateral stenosis with an intact contralateral kidney. Successful revascularisation (by angioplasty in 8, and surgery in 3) improved blood pressure and renal function, and virtually eliminated pulmonary oedema. In a second series of 55 consecutive patients with azotaemia and renovascular hypertension, pulmonary oedema occurred in 13 (23%). Blood pressure and renal function were not significant predictors of pulmonary oedema, but coronary heart disease and bilateral (vs unilateral) renal artery stenosis were. Bilateral renal artery stenosis may be a specific and treatable predisposing factor to pulmonary oedema in azotaemic hypertensive patients.

Percutaneous transluminal renal angioplasty in renovascular hypertension due to atheroma or fibromuscular dysplasia.

We attempted percutaneous transluminal renal angioplasty in 89 patients with hypertension and renal-artery stenosis (including 51 with atheromatous and 31 with fibromuscular stenoses) who were then followed for an average of 16 months (range, 4 to 40). Angioplasty was technically successful in 87 per cent of the fibromuscular stenoses and in 57 per cent of the unilateral atheromatous stenoses but in only 10 per cent of the bilateral atheromatous stenoses. After successful angioplasty, blood pressure was reduced to normal or improved in 93 per cent of the patients with fibromuscular dysplasia and in 84 per cent of the patients with atheromatous disease. Angiographic follow-up at an average of 21.8 months in 15 patients showed persistent relief of the stenoses and a 12 per cent average increase in kidney size. Renal angioplasty is effective for long-term control of hypertension in patients with renal-artery stenosis due to fibromuscular dysplasia or unilateral non-ostial atheroma.

Response of extravascular lung water to intraoperative fluids.

The effect of Ringer's Lactate (RL) and a colloid containing salt solution Plasmanate (PL) on extravascular lung water (EVLW) during aortic surgery was evaluated in a prospective study of 18 patients. Measured blood loss was replaced with packed red blood cells. In addition to red blood cell replacement, either RL or PL was infused (1) to maintain the cardiac output (CO) equal to or greater than the preoperative value, (2) to maintain the pulmonary capillary wedge pressure (PCWP) plus or minus 2 mmHg of preoperative values, and (3) to keep the urinary output greater than or equal to 30 cc/hr. Cardiac output, EVLW, PCWP, serum colloid osmotic pressure (COP), and intrapulmonary shunt fraction (Qs/Qt) were measured serially. All baseline values were similar between groups. The groups were well matched for age, associated disease, operating time, blood loss, and blood transfusions. During operation, the RL group required two times the rate of infusion of the PL group. Urine flow rates were similar on the day of surgery, but by postoperative days one and two, the PL group had approximately one-half of the urine flow rate compared to the RL group. Cardiac output and Qs/Qt increased in both groups. EVLW did not change after operation in either group, despite marked decrease in COP in the RL group. These data indicate that crystalloid resuscitation to physiologic endpoints does not increase extravascular lung water. Thus, manipulation of COP by PL was unnecessary in these patients.