William K. Ehrenfeld

Carotid plaque histology using real-time ultrasonography: Clinical and therapeutic implications☆☆☆

To evaluate the ability of ultrasonographic imaging to detect plaque hemorrhage in carotid atheroma, a study was undertaken that compared pathologic findings to preoperative ultrasonographic findings. Ultrasonography identified two plaque categories based on the heterogeneous and homogeneous echo patterns of the lesions studied. Heterogeneous lesions accounted for 91 percent of intraplaque hemorrhages (30 of 33) and 100 percent of ulcerated lesions (15 of 15). In 41 of 50 specimens (82 percent), ultrasonography correctly identified the presence or absence of plaque hemorrhage. False-negative studies (3 of 50) were due to the minute foci of remote hemorrhages. False-positive studies (6 of 50) resulted from plaques that contained large amounts of lipid or cholesterol. Preoperative ultrasound carotid imaging can be used to detect the histologic characteristics of plaque. Since recent clinicopathologic studies have implicated intraplaque hemorrhage and ulceration in symptomatic carotid disease, this information may be of value in choosing therapy, especially for the asymptomatic patient.

Effect of Carotid Endarterectomy on Carotid Chemoreceptor and Baroreceptor Function in Man

Abstract The ventilatory response to inhaled carbon dioxide was measured during hyperoxia (Pao2 over 200 torr) and hypoxia (Pao2 of 40 torr) in 14 patients before and one to nine weeks after caroti...

Monitoring with two-dimensional transesophageal echocardiography. Comparison of myocardial function in patients undergoing supraceliac, suprarenal-infraceliac, or infrarenal aortic occlusion.

When the aorta must be temporarily occluded at the suprarenal or supraceliac levels during surgery, the resulting large increase in afterload may make the myocardium ischemic, even though systemic and pulmonary artery pressures and cardiac output are maintained at normal levels. These traditional indices of myocardial well-being do not appear to be sufficiently sensitive, since cardiac complications are still the most frequent cause of perioperative death and morbidity after aortic reconstruction. To evaluate two-dimensional transesophageal echocardiography as a monitor of myocardial well-being, we studied 24 American Society of Anesthesiologists physical status class III or IV adult patients who were undergoing aortic reconstruction and occlusion at the supraceliac (n = 12), suprarenal-infraceliac (n = 6), or infrarenal (n = 6) level. In addition to traditional monitors, we used a gastroscope tipped with a special 3.5 MHz two-dimensional echocardiographic transducer (Diasonics) that was placed in the esophagus to give a cross-sectional view of the left ventricle through the base of the papillary muscles. The hemodynamic effects of clamping the aorta were managed by administration of vasodilating drugs, anesthetics, and fluids to keep systemic and pulmonary arterial pressures normal. Occlusion at the supraceliac level caused major increases in left ventricular end-systolic and end-diastolic areas, decreases in ejection fraction, and frequent wall motion abnormalities; these changes were not detected by conventional monitoring devices. Occlusion at the suprarenal-infraceliac level caused similar but smaller changes, and occlusion at the infrarenal level caused only minimal cardiovascular effects. We conclude that the two-dimensional transesophageal echocardiogram offers promise as an intraoperative monitoring device.

Late results following operative repair for celiac artery compression syndrome

The clinical significance of celiac artery compression by the median arcuate ligament of the diaphragm remains unsettled. The controversy stems from an undefined pathophysiologic mechanism and the existence of celiac compression in asymptomatic patients. This study was therefore conducted to evaluate the late results of operative therapy among our patients and possibly to identify parameters that might correlate with sustained symptom relief. Among 51 patients (12 men and 39 women) (mean age 47 years) who underwent operative treatment for symptomatic celiac artery compression, 44 (86%) were available for late follow-up. Their clinical status was determined between 1 and 18 years postoperatively (mean 9.0 years) by patient interview (36) or chart review (7). Operative treatment consisted of celiac axis decompression only (16 patients), celiac decompression and dilatation (17 patients), or celiac decompression and reconstruction by primary reanastomosis or interposition grafting (18 patients). Sustained symptom relief occurred more often with a postprandial pain pattern (81% cure), age between 40 and 60 years (77%), and weight loss of 20 pounds or more (67%). A negative correlation with clinical improvement was demonstrated for an atypical pain pattern with periods of remission (43% cure), a history of psychiatric disorder or alcohol abuse (40%), age greater than 60 years (40%), and weight loss of less than 20 pounds (53%). Eight of 15 patients (53%) treated by celiac decompression alone remained asymptomatic at late follow-up in contrast to 22 of 29 patients (76%) treated by celiac decompression plus some form of celiac revascularization. Late follow-up arteriograms (18 studies) showed a widely patent celiac artery in 70% of asymptomatic patients but a stenosed or occluded celiac axis in 75% of symptomatic patients. These findings suggest that persistent clinical improvement in patients with symptomatic celiac axis compression can be achieved by an operative technique that ensures celiac axis patency. Although some clinical features are identified that correlate with long-term benefit, reliable diagnosis of the symptomatic patient awaits definition of the pathophysiologic mechanisms involved in this syndrome.

Improved management of aortic graft infection: The influence of operation sequence and staging

To investigate the influence of operation sequence and staging on the outcome of aortic graft infection, we studied the mortality and amputation rates and incidence of new graft infection involving the extra-anatomic bypass (EAB) among 101 patients treated for secondary aortoenteric fistula (N = 43) or primary perigraft infection (N = 58). Patients were retrospectively grouped according to the operative treatment technique. Seven patients underwent infected graft removal (IGR) followed immediately by EAB (traditional). Fifty-seven patients were revascularized first, followed by immediate IGR in 38 patients (sequential) or by delayed IGR in 19 patients (staged). The median interoperative interval for the staged group was 5 days (range 2 to 31 days). Twenty patients underwent simultaneous IGR and in-line autogenous reconstruction (synchronous) and finally in 15 patients treatment consisted of IGR only with no extremity revascularization (none). The mean follow-up interval for all patients was 36.8 months. There was no statistically significant difference in mortality rate (traditional, 43%; sequential, 24%; and staged, 26%) or incidence of new graft infection (traditional, 43%; sequential, 18%; or staged, 16%) among those patients treated with EAB, although there was a trend toward an improved outcome with either sequential or staged treatment. There was a significantly lower amputation rate among sequential patients (11%) (p = 0.038) but not staged patients (16%) (p = 0.171) when compared with traditional treatment (43%). Staged operative treatment was associated with significantly less physiologic stress than sequential treatment as reflected by multiple perioperative metabolic variables (95% confidence limits). The treatment groups were comparable in the incidence of aortoenteric fistulas, culture-negative infections, emergent procedures, and appropriate antibiotic use. We conclude that reversed sequence or staged operative treatment of infected aortic grafts can be performed with no increased patient risk. Although traditional or sequential treatment may be required in the setting of acute hemorrhage, the staged operative approach is recommended for the treatment of chronic aortic graft infections.

Late results following surgical management of vascular graft infection

Ninety-two patients underwent surgical treatment for 59 prosthetic graft infections and 33 secondary aortoenteric fistulas. Definitive treatment was accomplished with a low perioperative mortality rate (14%). Long-term follow-up confirmed that most patients were cured of their infection or fistula, and 88% of the patients who survived the perioperative period (67 of 76) had no further evidence of infection when followed up from 10 months to 12 1/2 years postoperatively. The 12% late mortality rate (9 of 76) was secondary to persistent infection and aortic stump disruption. When perioperative and late deaths in both groups are combined, 67 of 92 patients (73%) were cured of their prosthetic graft infection. Factors associated with a favorable prognosis for survival and cure of infection were autogenous reconstruction and possibly staged operative repair. Poor prognosis for survival and cure of infection resulted from aortic stump disruption, persistent infection, and retained graft material. Significant morbidity (amputation and multiple operative procedures) was related to the severity of underlying vascular disease, the inadequacy of extra-anatomic reconstruction, and in some cases progression of vascular disease. The major challenges in the treatment of graft infection at present are the preoperative identification of limited graft infection and the successful management of the interrupted aorta. Complex and innovative reconstructive procedures continue to be necessary to ensure limb salvage and remain a considerable technical challenge. Nonetheless, the prospects for cure as reported in this series justify an aggressive operative approach. A successful outcome following definitive treatment of these devastating complications is possible for the majority of affected patients.

Secondary aortoenteric fistula: Contemporary outcome with use of extraanatomic bypass and infected graft excision☆☆☆★

PURPOSE The standard treatment for secondary aortoenteric fistula (SAEF) has been infected graft removal (IGR) and extraanatomic bypass (EAB), an approach criticized for its high rate of death, amputation, and disruption of aortic closure. Recently, graft excision and in situ graft replacement has been proposed as a safer treatment alternative. Because the current outcome that can be achieved by use of the standard treatment of SAEF has really not been established, we reviewed the records of 33 patients treated for SAEF at our institution during a contemporary time interval (1980 to 1992). METHODS Thirteen patients (39.4%) were admitted with evidence of gastrointestinal bleeding and infection, whereas nine (27.3%) only had bleeding, 10 (30.3%) only had signs of infection, and one SAEF was entirely occult (graft thrombosis). Four patients required emergency operation. The fistula type was anastomotic in 13 (39.4%) patients, paraprosthetic in 15 (45.5%), and not specified in 4 cases. Thirty-two patients underwent EAB followed immediately by IGR (n = 16, 48.5%) or followed by IGR after a short interval, averaging 3.9 days (n = 16, 48.5%). The final patient underwent IGR, followed by EAB. RESULTS Follow-up on 31 patients (93.9%) averaged 4.4 +/- 3.7 years. There were nine deaths (27.3%) resulting from the SAEF, six perioperative and three late. Three patients (9.1%) had disrupted aortic closure. There were four amputations in three patients (9.1%), two perioperative and two late. Late EAB infection occurred in five patients (15.2%), leading to one death and one amputation. EAB failure occurred in six patients, two during operation and four late, leading to one amputation. The cumulative cure rate for this SAEF group was 70% at 3 years and thereafter. Compared with our earlier SAEF experience, this is a decline of 21% in the mortality rate, 19% in aortic disruption, and 27% in limb loss. CONCLUSIONS We conclude that outcome reports based on SAEF series extending over long time intervals do not accurately represent the results that are currently achieved with standard SAEF treatment with use of EAB plus IGR. This improved outcome is attributed to wide debridement of infected tissue beds, reduced intervals of lower body ischemia, and advances in perioperative management. To determine whether any new treatment approach actually offers improved outcome in the management of SAEF, comparison with EAB plus IGR should be limited to patients treated within the last decade at most.

Does anesthetic technique make a difference? Augmentation of systolic blood pressure during carotid endarterectomy: effects of phenylephrine versus light anesthesia and of isoflurane versus halothane on the incidence of myocardial ischemia

Whether anesthetic technique affected the incidence of myocardial ischemia in 60 patients undergoing carotid endarterectomy was investigated. The patients were randomly assigned to receive halothane or isoflurnne (with nitrous oxide) either nt a low concentration alone or at a higher concentration with phenylephrine added to support blood pressure. Blood pressure wns maintained within 20% of each patients average ward systolic pressure. Seven leads of electrocardiograms (ECC) and echocardiograms were analyzed for segmental wall motion. The echocardiograms were analyzed using standard formulae for end-systolic meridional wall stress (SWS) and rntecorrected velocity of fiber shortening (Vcfc). Because of the nature of these calculations, only echocardiograms with normal regional wall motion could be accurately analyzed. The patients had postoperative ECG and creatinine phosphokinase (CPK)isoenzyme determinations and regularly scheduled clinical examinations to detect perioperntive myocardial infarction and neurologic deficits. Although blood pressures were similar, the patients who received a higher concentration of anesthetic plus phenylephrine had a higher wall stress, regardless of the choice of anesthetic agent. All four techniques allowed provision of the same stump pressures (the marker surgeons used for adequacy of collateral carotid flow). No difference could be found in wall stress or incidence of myocardial ischemia between isoflurane and halothane. The patients who received phenylephrine had a threefold greater incidence of myocardial ischemia than did the patients who had light anesthesia to maintain similar systolic blood pressures and stump pressures. The groups were demographically and hemodynamicnlly similar; in particular, the heart rates were not different. Increased wall stress in anesthetized patients is associated with an increased incidence of myocardial ischemia as evidenced by new segmental wall motion and wall thickening abnormalities (SWMA).

Durability of endarterectomy and antegrade grafts in the treatment of chronic visceral ischemia

Several techniques have been used to revascularize the visceral circulation. Although initially successful, these repairs often have a significant rate of late occlusion. To determine the durability of transaortic endarterectomy (TEA) and antegrade aortovisceral grafting, we reviewed the last 67 consecutive patients operated on at the University of California, San Francisco for chronic visceral ischemia. The patients were principally middle-aged (mean, 59 years) women (76%) with atherosclerotic disease involving at least two major visceral arteries. Forty-seven patients underwent TEA; 22 patients had associated renal endarterectomy, and 15 patients had simultaneous aortic reconstructions. Twenty patients had an aortovisceral antegrade bypass placed as their only reconstruction. Two of these had concomitant aortic reconstructions. There were five perioperative deaths. Of the 62 patients available for follow-up, 60 patients who had a total of 111 major visceral branch repairs have been followed up for 6 months to 14 years (mean, 4.4 years). Four patients (7%) have had recurrent visceral ischemia. Two patients had recurrent symptoms and have been asymptomatic for nearly 5 and 6 years, respectively, after successful reoperations. Two patients had intestinal infarction and died as a result. Thirty-four patients have had follow-up aortography that showed 58 widely patent reconstructions, two asymptomatic single-vessel stenoses, and one asymptomatic occlusion. TEA and antegrade visceral bypass provided long-term relief of symptoms and prevented visceral gangrene in 56 of 60 patients (93%). The prolonged patency of these reconstructions is attributed to the following: They originate from undiseased or endarterectomized aorta, they provide optimal, nonturbulent flow, and they avoid the inherent technical pitfalls of retrograde grafting.

Revascularization methods in chronic visceral ischemia caused by atherosclerosis.

A comparison of revascularization methods used in 35 patients who underwent 39 operations for chronic visceral ischemia caused by atherosclerosis is presented. All but two of these various methods have been abandoned either because of technical difficulties encountered during the procedure, or the high failure rate observed after operation. The two techniques which overcame these objections are: (1) antegrade aorto-celiac prosthetic grafts, and (2) transaortic endarterectomy using a thoracoretroperitoneal approach.