Endarterectomy for preventing stroke in symptomatic and asymptomatic carotid stenosis. Review of clinical trials and recommendations for surgical therapy.

BACKGROUND: Multicenter, randomized trials have demonstrated advantages for surgery over medical therapy in both symptomatic and asymptomatic carotid stenosis of greater than 70%. Controversial interpretations of these trials are debated between medical and surgical camps. The goal of this review is to summarize the current state of knowledge in carotid stenosis and the role of surgery and several advances in operative management. METHODS: Summaries of seven major controlled trials of carotid endarterectomy versus medical therapy are presented along with supportive data from over 90 related publications. Criticisms, deficiencies as well as strengths are offered. RESULTS: All studies in which trial design, clinical variables, case selection, complication definition, and patient follow-up were well conceived and performed showed statistically significant advantages for surgical therapy within a remarkable short interval of follow-up (less than 3 years). Carotid endarterectomy demonstrated a two to four fold reduction in the late incidence of stroke when compared to optimum medical management (risk factor reduction and initiation of antiplatelet therapy). Reduction in stroke risk over time remains stable in surgically treated patients whereas medically treated patients clearly show progression of stenosis and evolution of new neurologic events with time. Several studies indicate that diabetes is a risk factor for stroke with medical therapy that is eliminated by surgical therapy. Advantages were more clearly demonstrated when symptomatic patients (TIAs, stroke, or amaurosis) were studied, but asymptomatic patients received significant benefit as well. The degree of benefit measured was in direct balance to the perioperative risk. Perioperative stroke and death rates must be low (less than 3% combined for asymptomatic patients) in order for statistically significant differences to be detected. However, most centers now can perform carotid endarterectomy within these outcome parameters. CONCLUSIONS: Randomized trials support the safety and efficacy of carotid endarterectomy for stenosis greater than 70% (with or without symptoms). Advantages of surgery over medical therapy were found in less than three years and there is ample evidence to suggest that the differences between these groups would have been even more pronounced had longer follow-up been obtained. Thus for patients who face many years of risk after diagnosis of a carotid lesion, early surgery is the most important and effective intervention for preventing stroke. The results of these trials raised initial concern over increasing health care expenditures from rising surgical case volumes. However, studies of cost effectiveness confirmed that surgery saves health care dollars when compared to the long term care of stroke victims.

Isolation of Chlamydia pneumoniae from a carotid endarterectomy specimen.

Chlamydia pneumoniae has been associated with atherosclerotic cardiovascular disease by both seroepidemiologic studies and direct detection of the organism in atherosclerotic plaque by electron microscopy (EM), immunocytochemistry (ICC), and polymerase chain reaction (PCR). Despite the frequent detection of the organism in atheromatous cardiovascular specimens by these methods, only 1 cardiovascular isolate of C. pneumoniae, obtained from a coronary artery, has been previously reported. This study reports the isolation of C. pneumoniae from a prospectively obtained carotid endarterectomy specimen. The organism appears to be identical to other C. pneumoniae isolates by EM morphology, reactivity to species-specific monoclonal antibodies, and Southern hybridization analysis of chromosomal digests using C. pneumoniae-specific DNA probes. C. pneumoniae was detected by PCR or ICC (or both) in 11 (69%) of 16 other endarterectomy specimens tested by both of these methods. These results provide further evidence for an association of C. pneumoniae and atherosclerosis by confirming the presence of viable bacteria within atherosclerotic plaque.

Transcranial Doppler intraoperative monitoring during carotid endarterectomy: experience with regional or general anesthesia, with and without shunting.

To determine whether continuous transcranial Doppler (TCD) can significantly alter therapeutic conduct during carotid endarterectomy, a retrospective study of 117 carotid endarterectomies was done. There was no perioperative mortality; one perioperative stroke was recorded in a patient who was symptomatic preoperatively. Continuous TCD of the ipsilateral middle cerebral artery (MCA) was attempted in 99 cases, and successful in 90; nine patients (9.1%) had inadequate temporal windows for MCA access. MCA velocities and emboli were recorded before and during carotid cross-clamping, and on clamp release. There were no significant velocity differences between the patients with regional and general anesthesia, and patients with and without carotid shunts, but there was a statistically significant difference in the total number of emboli (air and particulate transients) noted for the shunted and nonshunted patients after clamp release: 12.7 versus 23.6, respectively (p = 0.05). There was no significant difference when particulate and air microemboli were compared. During surgery TCD identified residual flow of less than 40% in the MCA in 17 patients (18.8%). TCD also identified hyperperfusion in two patients, shunt abnormalities in three patients, and influenced postop treatment in four patients, one of whom was returned to surgery. TCD is an important tool for identifying patients who would benefit from a shunt, preventing hyperperfusion, identifying postop emboli, and detecting technical errors.

Preliminary experience with the Hutson-Russell loop cutaneous choledochojejunostomy.

In 1984, the use of a choledochojejunocutaneous fistula was described to allow balloon dilation of benign biliary strictures. Later, the use of the technique to obtain repeated access to the biliary tree in a larger series of patients was reported. The experience provided a foundation for the application of the technique in nine patients at Wilford Hall United States Air Force Medical Center. Represented were a variety of benign and malignant disorders. Six patient reports are offered from this preliminary experience to demonstrate the range of problems lending themselves to the use of the Hutson-Russell loop. Suggestions for present and future applications of the versatile choledochojejunocutaneous loop are included.

Colonic lipoma as a source of massive hemorrhage. Report of a case.

Colonic lipomas are a rare source of massive lower gastrointestinal bleeding requiring operative intervention. A case of massive hemorrhage from cecal lipomatosis is presented. The methods of preoperative diagnosis and treatment are discussed.