Use of duplex imaging to assess suitability of the internal mammary artery for coronary artery surgery

The internal mammary artery is the preferred conduit for coronary artery surgery. To determine the role, if any, of preoperative duplex imaging in assessing the suitability of this vessel, preoperative noninvasive measurements of internal mammary artery diameter and blood flow were performed in 243 patients. The left internal mammary artery was insonated through the third intercostal space by use of duplex scanner (5.0 MHz probe) before coronary artery surgery. Internal mammary artery diameter (millimeters), peak systolic velocity (centimeters/second), and mean velocity (centimeters/second) were measured, and internal mammary artery flow was calculated from velocity and cross-sectional area. In 45 of these patients the internal mammary artery diameter also was measured during surgery with a sterile caliper, and blood was collected for 30 seconds from the transected internal mammary artery to measure flow. These findings were compared to the preoperative values. In 243 patients the mean internal mammary artery diameter was 2.34 +/- 0.03 mm, and mean peak systolic blood flow was 226.7 +/- 6.3 ml/min. In the 45 patients in whom intraoperative measurements were obtained, preoperative mean internal mammary artery diameter was 2.39 +/- 0.05 mm and was not significantly different from the intraoperative mean internal mammary artery diameter of 2.36 +/- 0.04 mm. Preoperative peak systolic flow was 231.3 +/- 8.1 ml/min, and mean flow was 110.3 +/- 7.1 ml/min; intraoperative flow measured 136 +/- 3.6 ml/min. Noninvasive determinations correlated with operative findings for internal mammary artery diameter (r = 0.87) (p less than 0.05), peak systolic blood flow (r = 0.70) (p less than 0.05), and mean blood flow (r = 0.60) (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

The role of carotid screening before coronary artery bypass

Five hundred thirty-nine patients with no symptoms of cerebral ischemia undergoing coronary artery bypass were preoperatively evaluated for presence of carotid stenosis by noninvasive methods (duplex scanning and ocular pneumoplethysmography-Gee). Overall prevalence of carotid stenosis greater than 75% was higher (8.7%) than that generally reported. Age greater than 60 years was significantly related to presence of carotid stenosis greater than 75% (11.3% vs 3.8%, p = 0.003). Risk factors such as hypercholesterolemia, hypertension, diabetes mellitus, and smoking were not predictive for carotid stenosis, postoperative stroke, or death. Carotid stenosis greater than 75% (odds ratio 9.87, p less than 0.005) and coronary artery bypass redo (odds ratio 5.26, p less than 0.05) were both independent predictors of stroke risk. Patients were divided into four groups: group 1, minimal or mild degree of carotid stenosis (less than 50%), not submitted to prophylactic carotid endarterectomy (432 patients, 80.1%); group 2, moderate degree of stenosis (50% to 75%), no prophylactic carotid endarterectomy (60 patients, 11.2%); group 3, severe carotid stenosis; (greater than 75%), submitted to prophylactic carotid endarterectomy (19 patients, 3.5%), group 4, severe carotid stenosis (greater than 75%) no prophylactic carotid endarterectomy (28 patients, 5.2%). Patients in group 4 had significantly higher stroke rate (14.3%) compared to the other three groups (1.1%) (p = 0.0019). The finding of carotid stenosis greater than 75% in patients over 60 years of age was associated with occurrence of stroke in 15% of cases. Carotid screening is helpful to determine patients at increased risk of stroke and should be performed in patients greater than 60 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Seizures following carotid endarterectomy

Cerebral infarction, headache, and hypertension are well-known complications of carotid endarectomy (CEA). Seizures are a less frequent, but important complication. We describe eight patients with focal and generalized seizures following CEA. Seizures occurred 6 to 13 days after CEA. All began as focal motor seizures contralateral to the side of the CEA, and six patients developed generalized tonoclonic seizures. Lorazepam and phenytoin sodium controlled the seizures. Five patients without evidence of stroke on computed tomographic scan were normal in follow-up and had no further seizures. The other three patients had mild deficits. One developed a chronic seizure disorder. The pathogenesis of this syndrome following CEA remains unclear, but may involve cerebral hyperperfusion, cerebral embolization, or both.

Plaque characterization by B-mode scan

High-resolution ultrasound technology provides anatomic information on the nature of the vessel wall. As such, it is a complementary modality to both frequency analysis, which provides flow data, and angiography, which describes vessel lumen. At present, the technology is most effectively applied to superficial vessels such as the carotid, common femoral, and popliteal arteries. Measurement can be compromised by heavy vessel calcification, and the technique is most useful in mild to moderate disease. Prospective blinded trials have shown that HRUS can be used to determine lumen diameter and per cent stenosis, although its accuracy is improved by adding frequency analysis. The technique is most useful for interrogating the atherosclerotic plaque itself; as such, it appears superior to angiographic techniques. Several investigators have documented the ability of HRUS to characterize plaque and particularly to identify intraplaque hemorrhage and ulceration. Criteria for diagnosis remain difficult to standardize and, for the moment, must be developed for each center involved in these studies. The future of HRUS appears to lie in development of more detailed analyses of plaque morphology and the study of atherosclerotic disease in large populations over time.

Reexploration for thrombosis in carotid endarterectomy

We reviewed the records of patients undergoing carotid endarterectomy and manifesting either postoperative stroke or thrombosis by oculopneumoplethysmography (OPG-Gee) to analyze the etiology of stroke and to determine the indications for reexploration. Of 900 consecutive elective endarterectomies performed during an 8-year period, 41 patients experienced a perioperative stroke, carotid thrombosis, or both. These patients were subdivided into three groups: group 1, 22 patients with perioperative stroke and carotid thrombosis; group 2, six patients with carotid thrombosis but without symptoms; and group 3, 13 patients with postoperative stroke but no thrombosis. In group 1, 17 patients were reexplored (group 1a), and five were observed without reexploration (group 1b). In group 2, three of the patients were reexplored (group 2a), and the remaining three were observed (group 2b). None of the group 3 patients were reexplored. In group 1a, four (23%) patients awoke from anesthesia with neurological deficits, whereas in group 3, nine (69%) patients awoke with such deficits. Follow-up at 30 days revealed that 76% of group 1a patients demonstrated improvement in symptoms, whereas similar results were seen in only 20% of group 1b patients and 23% of group 3 patients. These trends were maintained throughout the follow-up period of 1-5 years. Those patients who were asymptomatic, group 2, with thrombosis were more likely to have been operated on for asymptomatic carotid stenosis. with thrombosis were more likely to have been operated on for asymptomatic carotid stenosis. Thrombosis was the most common cause of postoperative stroke (63%) in patients after carotid endarterectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk factors in a community experience with carotid endarterectomy

Experience with 1035 carotid endarterectomies in a single community over a 2-year period was analyzed. Twenty-two surgeons working in six hospitals were involved. All surgeons had full-time or part-time appointments at the University of Rochester, 18 had special interest in vascular surgery, and eight had obtained a certificate of qualification in vascular surgery. Mortality rate was 1.4% (14 deaths), with additional permanent, nonfatal, neurologic morbidity of 3.4%. Mortality and morbidity were independent of surgeon, caseload, or hospital. Age and prior history of myocardial infarction influenced the incidence of postoperative myocardial infarction but not the incidence of death or neurologic morbidity. Factors that increased the risk of postoperative death or neurologic complication included hypertension; contralateral carotid disease as manifested by stroke, endarterectomy, or occlusion; whether the patient was a woman; and symptoms of crescendo ischemia. Lack of preoperative neurologic symptoms was correlated with decreased risk of myocardial infarction and neurologic complications. Overall mortality and neurologic morbidity associated with operation for "asymptomatic stenosis" was 3.1% (seven of 222 cases). However, the incidence of contralateral carotid disease was high in the patients in the asymptomatic group (60%), and all complications in this group occurred in patients with prior contralateral carotid endarterectomy or occlusion (p less than 0.05).

Influence of cadaveric organ source on delayed renal allograft function

From 1984 to 1987, 110 locally retrieved cadaveric kidneys were transplanted into 108 local recipients, including 50 kidneys from multiple-organ retrieval (MOR) procedures and 60 from kidney-only (KO) donors. Conventional multiple organ retrieval technique, iced Euro-Collins storage, and cyclosporine-prednisone immunosuppression were employed. Delayed graft function (DGF), defined as dialysis dependence after transplantation, was twice as high in the MOR allografts as in the KO allografts, 46% vs. 22%, P less than 0.01. DGF was associated with longer hospitalization postoperatively and reduced eventual allograft function. The greater concordance of DGF in allograft pairs from the MOR group (25% vs. 7% in the KO group) and the increased incidence of DGF when more complex forms of MOR were used (40% with liver or heart retrieval, 55% with liver and heart retrieval) suggested that retrieval-related factors influenced allograft function. DGF in the MOR allografts was unrelated to other differences in donor, preservation, or recipient characteristics in the comparative groups. Unrecognized warm ischemia during conventional MOR is a plausible cause of DGF in kidneys from multiple-organ donors.

Results of supraceliac aortic clamping in the difficult elective resection of infrarenal abdominal aortic aneurysm

We have used clamping of the aorta above the celiac axis (SC) in 30 of 431 elective resections of infrainguinal abdominal aortic aneurysms (AAA) during the past five years as an alternative to a difficult aortic cuff dissection. The results of SC clamping in these 30 patients are compared with the results of 379 routine aneurysm resections with infrarenal (IR) clamping and 22 additional aneurysm resections where the clamp was placed immediately above the renal arteries. These difficult cuff dissections occurred in 12 patients with inflammatory AAA, in 11 patients with juxtarenal AAA, and in seven patients with recurrent or noninfected false AAA of the proximal cuff. Patients with ruptured or suprarenal aneurysms and those undergoing combined operation for a visceral ischemic syndrome and an aneurysm were excluded from this study. Patients with SC clamping had similar operative mortality rates, comparable renal function, and frequency of cardiac events as patients with IR clamping. Blood loss was slightly higher in the SC group (p = 0.07) and serum aspartate amino transferase (AST) levels were three times higher than in the IR group; however, this was of no clinical significance. In contrast, those 22 patients whose aortas were clamped immediately above the renal arteries (AR) had higher perioperative mortality rates (2% IR, 3% SC vs 32% AR) and a higher incidence of kidney failure requiring dialysis (1% IR, 3% SC vs 23% AR). The mean values of serum creatinine and blood urea nitrogen were also significantly higher in the AR group when compared with both the IR and the SC groups (IR: 25 and 1.5 mg/dl, respectively; SC: 27 and 1.8 mg/dl; AR: 41 and 3.5 mg/dl). The single most important risk factor accounting for the differences between clamping above the celiac artery and clamping above the renal arteries was the presence of atherosclerotic debris in the nonaneurysmal, juxtarenal aortic segment. Clamping the aorta with juxtarenal atherosclerosis caused either atheroembolization to kidneys, legs, and intestine or injury to the aorta, renal arteries, or both; it was the cause of morbidity in all five cases of kidney failure requiring dialysis and accounted for all seven of the deaths in the AR group. SC clamping does not add risk to the patient undergoing resection of an infrarenal AAA and is the preferred method of achieving proximal control of the infrarenal aorta when a a hazardous cuff dissection is likely.(ABSTRACT TRUNCATED AT 400 WORDS)

Platelet avidity of cryopreserved veins: thrombogenicity of cryopreserved veins

Prior work has suggested that cryopreserved venous allografts may serve as an effective arterial substitute. To determine the relative thrombogenicity of this material, platelet uptake of cryopreserved canine jugular veins (CJV) before and after deendothelialization was compared to fresh CJV before and after deendothelialization, and to PTFE. CJV were frozen in Medium 199 (M199) with 10% dimethylsulfoxide to -70 degrees C. CJV were deendothelialized with collagenase (165 u/mg Worthington type II in phosphate-buffered saline) for 15 min at 37 degrees C. Canine platelets were harvested, labeled with indium-III-oxine, and suspended in 1 liter of M199. Labeled platelets were used to perfuse each graft in a nonpulsatile flow loop for 120 min. Deendothelialization led to a significant increase in platelet uptake (P less than 0.05). Frozen deendothelialized CJV showed the highest affinity for platelets. PTFE, cryopreserved, and fresh CJV showed similar affinity for platelets. Cryopreservation alone did not seem to inhibit the ability of endothelial cells to act as a nonthrombogenic surface and did not alter the histologic structure of the veins.

Long-term clinical observations and venous functional abnormalities after asymptomatic venous thrombosis following total hip or knee arthroplasty

The long-term clinical and physiological sequelae of venographically diagnosed, asymptomatic postoperative venous thrombosis were studied in a group of 51 patients following total hip or total knee arthroplasty. After a mean follow-up period of 49.7 months, the patients were recalled for interview, physical examination, air plethysmography (APG), and photoplethysmography (PPG). At the time of follow-up examination, legs with prior postoperative venous thrombosis were not more likely to have clinical findings of deep venous insufficiency than legs with a negative venogram. Abnormal venous emptying, as measured by APG, was significantly correlated (p less than 0.005) with postoperative venous thrombosis and was found in patients with both proximal and calf vein thrombi, but was not clearly associated with symptoms. There was, however, a significant correlation (p less than 0.0005) between clinical findings of venous insufficiency and incompetent valves, as reflected by rapid refilling time after exercise shown by PPG. The findings indicate that asymptomatic postoperative venous thrombosis involving calf or proximal veins can lead to abnormal vein function, but is not closely correlated with later development of symptoms. These observations also suggest that symptomatic venous insufficiency is more closely associated with calf vein valve incompetence than with proximal vein obstruction.

Observations on cerebral computed tomography in patients having carotid endarterectomy

A review was undertaken of all patients seen in our institution between January 1978 and March 1987 in whom a cerebral CT scan was obtained in association with elective carotid endarterectomy. Three hundred fifty-nine such patients were identified. In a subgroup of 89 patients who were neurologically normal after carotid endarterectomy, scans were performed at least 48 hours after surgery to quantitate the incidence of silent postoperative infarction. These scans were interpreted by one neuroradiologist. Preoperative cerebral CT scans showed ipsilateral infarction in 146 of 359 patients (40.6%). Ipsilateral infarction was most common in patients with stroke (76%) but was also seen in 32.8% of patients with transient ischemic attacks, in 9 of 40 patients (22.5%) with nonhemispheric symptoms, and in 9 of 45 patients (20%) with asymptomatic hemodynamically significant carotid stenosis. The postoperative stroke rate was not significantly increased by the presence of infarct on preoperative cerebral CT scan (2.6% vs 1.9%). New infarcts were seen on cerebral CT scanning after carotid endarterectomy in 2 of 89 patients with no detectable neurologic abnormality (2.3%). This study demonstrates a high frequency of ipsilateral infarction in patients having elective carotid endarterectomy, even in those patients with clinical symptom complexes thought by many physicians to be relatively benign (i.e., transient cerebral ischemia, nonhemispheric ischemia, and asymptomatic carotid stenoses).(ABSTRACT TRUNCATED AT 250 WORDS)

Upper extremity claudication 10 years after a Blalock-Taussig shunt treated with a carotid-to-subclavian graft

A case of progressive upper extremity vascular insufficiency, which occurred 10 years after the construction of a Blalock-Taussig anastomosis, is described. It was successfully managed with a carotid-to-subclavian bypass graft.

Multicenter validation study of real-time ultrasonography, arteriography, and pathology: pathologic evaluation of carotid endarterectomy specimens

The morphologic description and measurements of endarterectomy specimens are usually believed to be accurate and are used as the gold standard against which the findings of diagnostic procedures are judged. Pathology data on 289 endarterectomy specimens from five participating centers and the corresponding angiography and B-mode ultrasonography data provided a basis for scrutinizing the validity of using the morphologic measurements as a standard. Discrepancies of greater than 1 mm between pathology and angiography measurements of minimum residual lumen occurred in 35% of the cases and between pathology and B-mode ultrasonography measurements in 64% of the cases. Discrepancies of greater than 1 mm between pathology- and angiography-measured lesion width occurred in 81% of the cases and between pathology and B-mode ultrasonography measurements in 64% of the cases. The cases representing mismatches of greater than 1 mm at one participating center were subjected to a rigorous review, with remeasurement of all morphologic features, in an attempt to explain the discrepancies. Various types of artifactual distortion of the specimens, the presence of slit-like and occluded lumens that were likely related to loss of perfusion pressure, and an inability to match planes of interrogation used in angiography and B-mode ultrasonography with pathology planes contributed significantly to the existence of mismatches. On the other hand, fixation and decalcification produced minimal and insignificant distortional changes. We conclude that the acquisition of quantitative data from endarterectomy specimens and the acceptance of morphologic data as a standard are limited by a number of problems that can be defined but have been difficult to resolve.