Neurologic events following carotid endarterectomy: prediction of outcome.

A total of 1572 carotid endarterectomies were performed at one institution between 1975 and 1987. One hundred five patients had early (< 3 weeks) neurologic events following carotid endarterectomy. Sixty-five patients had cerebral vascular accidents (CVAs) (4.1%), 14 patients had reversible ischemic neurologic deficits (0.9%), and 26 patients had transient ischemic attacks (1.7%). Eight patients died from CVAs (0.5%). The mean follow-up was 31 months (range 1 to 137 months) with a 5-year cumulative survival of 77%. The median time of occurrence of neurologic events was 4 hours. Ages, cerebral protection, patches, carotid occlusion time (mean 29 minutes), gender, and status of the contralateral carotid arteries were not predictors of outcome. Death from neurologic events increased significantly in patients who had preoperative CVAs compared with patients with preoperative transient neurologic deficits (p < 0.05). The time of occurrence of CVA after carotid endarterectomy affected outcome, and an early CVA (< 4 hours) was associated with a higher mortality at 30 days and at 4 months as a consequence of the initial CVA (p = 0.11). Patients who had a neurologic event more than 4 hours after surgery had a significantly better resolution of their symptoms (66%) compared with patients who had an early neurologic event (35%, p < 0.05). The long-term follow-up of the surviving patients demonstrated an improvement in neurologic function in 75% of the CVA group (36/48) and 92% (76/83) of all patients who had neurologic events in long-term follow-up.

Factors determining survival after ruptured aortic aneurysm: the hospital, the surgeon, and the patient.

The 10-year experience of a single community was reviewed and a multivariate analysis was performed to determine the relative importance of clinical and environmental factors in mortality after ruptured abdominal aortic aneurysm resection. Ruptured aneurysms were repaired in 243 patients in six area hospitals (one university, five community) by 25 surgeons (16 vascular, 9 general). Overall, 30-day mortality was 55% (133/243). Although the mortality by hospital ranged from 44% to 68%, these differences were not statistically significant. However, significant variations occurred in the mortality rates of individual surgeons, ranging from 44% to 73%. The mortality rate for the vascular surgeons was less than that of the general surgeons, 51% versus 69% (p less than 0.05). Clinical factors were evaluated, and the most significant parameters were systolic blood pressure, presence of chronic obstructive lung disease, and history of chronic renal insufficiency. These results support the implication that the degree of specialization of the surgeon and the preexisting health of the patient are the most important determinants of survival after ruptured abdominal aortic aneurysm. The size and sophistication of the hospital appear to be less influential factors.

Differential effects of a gram-negative and a gram-positive infection on autogenous and prosthetic grafts.

A canine model was developed to study the differential response of a gram-negative and a gram-positive bacterial infection on autogenous and prosthetic grafts. After replacing segments of the femoral arteries of 15 dogs with autogenous vein in one groin and polytetrafluoroethylene in the contralateral groin, 10(8) colony-forming units of nonmucin-producing Staphylococcus epidermidis (five dogs), Pseudomonas aeruginosa (five dogs), or sterile saline solution (five dogs) were directly inoculated onto the grafts. The grafts were examined 7 to 10 days after implantation. None of the control dogs exhibited inflammatory signs, and no grafts or anastomoses disrupted. S. epidermidis was unrecoverable from either graft material in any of the animals, although histologic evaluation confirmed neutrophils and bacteria in four of five animals in the vein and polytetrafluoroethylene groups. No dog inoculated with S. epidermidis had graft or anastomotic disruption. By contrast, P. aeruginosa was recovered from both types of grafts in all inoculated animals. Neutrophils, bacteria, and microabscesses were observed in all of these animals. In addition, three of five polytetrafluoroethylene grafts and all five vein grafts disrupted either at the anastomoses or in the body of the vein graft. Therefore S. epidermidis is a less virulent organism that may persist in graft walls despite negative cultures, whereas P. aeruginosa is a highly virulent organism that can disrupt native artery, vein grafts, and anastomoses. The graft material appears to be less important than the bacteria in determining the outcome of infection.

Limb-threatening ischemia in the medically compromised patient: amputation or revascularization?

The clinical courses of 362 patients with threatened limbs, seen over a 25-year period, were reviewed. Below-knee amputation was elected in 158 patients and infrainguinal revascularization in 204 patients. Patients were excluded from the study if amputation was chosen on the basis of arteriographic findings, diffuse infection, or extensive tissue loss. In an effort to compare the two treatment modalities in a minimally biased fashion, patients were stratified into three classes on the basis of the Goldman Multifactorial Index of Cardiac Risk and the American Society of Anesthesiology classification. Within each class, patients treated with amputation and with bypass were comparable with respect to age, sex, severity of ischemia, and anesthetic technique. Patients who underwent revascularization had a lower perioperative mortality rate (p less than 0.05), a shorter length of hospital stay (p less than 0.05), and an increased long-term survival rate (p less than 0.05) than the medically matched subgroup of patients who underwent amputation. Patients in the revascularization group were more successful in regaining ambulatory abilities than patients in the amputation group (p less than 0.01). These differences were most significant as the degree of medical compromise increased. Although medically compromised patients have frequently been denied revascularization on the basis of presumed increases in surgical risk and decreased long-term survival, the data appear to suggest that it is precisely the patients of this group who appear to benefit the most from attempts at limb salvage.

Detection of occult colonic ischemia during aortic procedures: use of an intraoperative photoplethysmographic technique.

A photoplethysmographic technique was used in 30 consecutive patients who had abdominal aortic reconstruction to assess colonic viability intraoperatively. A sterile pulse oximeter probe was used to measure arterial pulsatility and transcolonic oxygen saturation (TCOS) in the proximal, midportion, and distal sigmoid colon before and after the reconstruction. No attempt at inferior mesenteric revascularization was made, irrespective of the photoplethysmographic results. The status of the colon was assessed between the third and sixth postoperative day by a colonoscopist unaware of the intraoperative data. Before the reconstructive procedure photoplethysmography displayed pulsatile flow in all patients with a mean TCOS of 95% +/- 0.4%. After reconstruction, 28 patients (93%) demonstrated unchanged pulsatility with mean TCOS of 94% +/- 0.4%. Despite ligation of a patent inferior mesenteric artery in 10 of these patients, all 28 had normal colonoscopic examinations. By contrast, two patients (6.7%) had a loss of photoplethysmographic pulsatility with unmeasurable TCOS. Both of these patients had ligation of an initially patent inferior mesenteric artery and demonstrated evidence of ischemic mucosal changes at colonoscopy. Intraoperative colonic photoplethysmography represents an easily performed, accurate method for predicting colonic viability. A loss of pulsatility suggests inadequate postreconstructive colonic perfusion and mandates revascularization of the inferior mesenteric artery.

High-risk aortic aneurysm repair with partial cardiopulmonary bypass.

Two patients with severe cardiac dysfunction and measured left ventricular ejection fractions of 18% and 20% underwent aneurysm repair with the use of femoral vein--femoral artery partial cardiopulmonary bypass. While the aorta was clamped, blood was withdrawn through the venous cannula, and oxygenated blood was delivered to the legs through the arterial cannula. This procedure allowed clamping and unclamping of the aorta to proceed without hemodynamic fluctuation. Intraoperatively, cardiac output, mean arterial pressure, pulmonary artery diastolic pressure, right atrial pressure, pulmonary capillary wedge pressure, and systemic vascular resistance were measured. Both patients recovered, which indicates that this technique may be safely undertaken in the severely compromised patient with cardiac disease.

Acute aortic rupture from cross clamp injury.

We report a case of transmural disruption and perforation of the abdominal aorta secondary to clamp injury. The literature is reviewed in reference to the traumatic effects of vascular clamps. Steps are outlined to reduce the risk of this injury.

Vocal cord paralysis following carotid endarterectomy.

From 1964 to 1977, over 400 carotid endarterectomies were performed at the Rochester General Hospital. Two patients from this group experienced hoarseness secondary to vocal cord paralysis on the operated side, believed due to trauma to the vagus nerve. Although uncommon, it is important to stress the method of avoiding this complication.

A laboratory system for production of flexion rates and forces in the forelimb of the horse.

The distal portion of the forelimb of the horse is provided with a stay apparatus composed of tendons, ligaments, and fascia. This stay apparatus provides the major resistance to joint flexion during the support phase of the stride. The laboratory test system described was shown to be able to reproduce in vitro limb motions and hoof forces measured with a running horse. These results indicated the stay apparatus operates in a largely passive mode, active muscle contraction apparently serving to provide rigidity only early in the support phase of the stride. The testing system described was designed to take advantage of the passive nature of the stay apparatus in order to study in vitro the forces, accelerations, and deformations encountered by the limb of the galloping horse in vivo.

Femoro-popliteal by-pass with bovine heterografts.

Modified bovine heterografts were used in 28 patients, primarily extremity salvage problems, found to have unavailable or unusable saphenous veins. The accumulated 3 year patency rate was 35%. Of the 18 graft failures, 11 required major amputation. A high failure rate of 39% in the first six-month interval was observed. Electromagnetic flowmeter recording were of limited value in predicting patency. Continued evaluation of bovine grafts for femoro-popliteal reconstruction in the absence of saphenous vein is recommended.