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This report documents a case of completely spontaneous ascending aortic disruption. A 54-year-old African American male day laborer presented with severe retro-sternal chest and back pain and shortness of breath. He had no history of hypertension, smoking, or trauma and was taking no medications. The computed tomographic angiography scan performed to exclude pulmonary embolism instead demonstrated a hemorrhagic pericardial effusion and an ascending aortic pseudoaneurysm. He was taken emergently to the operating room for repair of his ascending aorta. The histopathology report was normal., (Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Excessive alcohol use can cause macrostructural tissue shrinkage with regional preference for frontal systems. The extent and locus of alcoholism's effect on white matter microstructure is less known., Methods: Quantitative fiber tracking derived from diffusion tensor imaging (DTI) assessed the integrity of samples of 11 major white matter bundles in 87 alcoholics (59 men, 28 women) and 88 healthy control subjects (42 men, 46 women). Fiber integrity was expressed as fractional anisotropy (FA) and apparent diffusion coefficient (ADC), quantified separately for longitudinal diffusivity (lambdaL), a putative index of axonal integrity, and transverse diffusivity (lambdaT), a putative index of myelin integrity., Results: Alcoholism affected FA and diffusivity, particularly lambdaT, of several fiber bundles. Frontal and superior sites (frontal forceps, internal and external capsules, fornix, and superior cingulate and longitudinal fasciculi) showed greatest abnormalities in alcoholics relative to control subjects. More posterior and inferior bundles were relatively spared. Lifetime alcohol consumption correlated with regional DTI measures in alcoholic men but not women. When matched for alcohol exposure, alcoholic women showed more DTI signs of white matter degradation than alcoholic men in several fiber bundles. Among all alcoholics, poorer performance on speeded tests correlated with DTI signs of regional white matter degradation., Conclusions: This survey of multiple brain fiber systems revealed a differential pattern of alcoholism's effect on regional FA and diffusivity with functional consequences attributable in part to compromised fiber microstructure with prominence in signs of myelin degradation. Sex-based differences suggest that women are at enhanced risk for alcoholism-related degradation in selective white matter systems.

Volumes of thalamus, pons, cortical gray matter, and white matter were derived from MR brain images of healthy men and women spanning the adult age range in order to delineate patterns of aging and to compare age and sex effects in thalamus and pons with such effects in cortical gray and white matter volumes. Men had larger intracranial volume (ICV) than women, but ICV did not correlate with age in either sex. Thalamic, pontine, and cortical white matter volumes did not differ between men and women once ICV differences were taken into account, but men had more cortical gray matter than women even after accounting for ICV. Volumes of pons and thalamus were associated, independent of ICV, in women but not in men. Thalamic volume declined linearly with age at a similar rate in both men and women, whereas cortical gray matter volume declined more steeply with age in men than women. Both pontine and cortical white matter volumes remained stable across the age span in both men and women.

This quantitative MRI study reports measurement of corpus callosum area taken from midsagittal brain images in 51 healthy men and 41 healthy women, spanning the adult age range (22 to 71 years). Men had larger brains and corpora callosa than women, but callosal size did not correlate with age in either sex. Intracranial (i.c.) volume (ICV) and midsagittal i.c. area (ICA) of brain were used in covariate, regression, and ratio analyses to determine whether sex differences in the corpus callosum endured with statistical adjustment for sex differences in maximally attained brain size. With the exception of one ratio measure, the different statistical adjustments for the contribution of sex differences in brain size to corpus callosum size all indicated that men had larger corpora callosa than women for their brain size. A subsample of men and women selected to be matched on i.c. volume and age confirmed this statistical observation. Sexual dimorphism in the corpus callosum is not a simple artifact of sex differences in brain size and may reflect differences in connectivity necessitated by differences in brain size.

Background: The P300 component of the auditory event-related potential (ERP) is both reduced in amplitude and delayed in schizophrenia. P300 is prolonged and, less consistently, reduced with normal aging. Additional latency delays are observed in neurodegenerative disorders. We asked whether P300 is reduced and delayed with longer illness duration in schizophrenia, consistent with a neurodegenerative process., Methods: P300 amplitude and latency were recorded to infrequent auditory target stimuli from 35 men with schizophrenia (DSM-III-R) and 26 control men. Effects of current age, age of onset, and duration of illness on P300 were assessed using regression analysis., Results: P300 amplitude showed no age-related decrease in either group; however, among schizophrenic participants, P300 amplitude correlated positively with onset age and negatively with illness duration. P300 latency correlated positively with age in schizophrenic participants and also tended to increase with age in controls. Slopes of the latency-age relationships were significantly greater in schizophrenic participants than in control participants. Latency also correlated positively with illness duration but showed no relationship to onset age., Conclusions: P300 amplitude and latency are reduced and delayed with longer illness duration in schizophrenia, consistent with a progressive pathophysiological process. Reduced P300 amplitude may also be a marker of an early onset variant of schizophrenia.

Background: Clozapine has shown considerable therapeutic promise in the treatment of schizophrenia; however, the clinical risks and initial high treatment costs associated with its administration motivate the search to identify patients who will best respond. Neuroimaging studies have suggested that prefrontal sulcal prominence may be a predictor of nonresponsiveness., Methods: We used magnetic resonance imaging (MRI) to test whether volumes in any cortical regions of the brain were associated with symptom improvement with clozapine treatment. The 21 schizophrenic men studied were clinically evaluated during treatment with typical neuroleptics (baseline) and after a mean of 6.2 months treatment with clozapine (final dose 300-900, median = 562 mg/day). At least a 20% improvement on total Brief Psychiatric Rating Scale (BPRS) was seen in 47.6% of the schizophrenics. Clinical improvement was regressed on baseline differences in clinical severity, and the residual scores were related to MRI values., Results: Patients with larger anterior superior temporal lobe cerebrospinal fluid volumes (primarily sylvian fissure) showed greater improvement on total BPRS and withdrawal/retardation symptoms., Conclusions: Even schizophrenics with significant brain dysmorphology can have a positive clinical response to clozapine.

Background: The optimal timing for coronary artery bypass grafting (CABG) after acute myocardial infarction (MI) remains controversial., Methods: We examined our experience retrospectively in 3,942 patients who underwent CABG between 1986 and 1993, including 2,296 patients after acute MI., Results: The operative mortality associated with increasing time intervals between MI and CABG were 9.1%, 8.3%, 5.2%, 6.5%, and 2.9%, for less than 6 hours, 6 hours to 2 days, 2 to 14 days, 2 to 6 weeks, and more than 6 weeks, respectively. In comparison, the operative mortality was 2.5% for patients with no history of acute MI. The incidence of permanent stroke and perioperative MI were greater and the length of postoperative hospitalization was longer for patients undergoing CABG early after MI. For patients undergoing operation electively, however, the operative mortality associated with increasing time intervals between MI and CABG were less, at 0.0%, 3.6%, 2.1%, 6.4%, and 2.1% for less than 6 hours, 6 hours to 2 days, 2 to 14 days, 2 to 6 weeks, and more than 6 weeks, respectively. For patients undergoing CABG within 14 days of MI, the operative mortality was 5.3% for those receiving an intraaortic balloon pump preoperatively for postinfarction angina, but 11.8% for those who underwent urgent/emergent operation without intraaortic balloon pump support., Conclusions: Elective CABG can be accomplished with acceptable morbidity and mortality early after acute MI if an elective operation is possible. In addition, the intraaortic balloon pump should be used aggressively in patients with postinfarction angina to allow for elective rather than urgent/emergent operation.

The usefulness of preoperative coronary arteriography in patients with type A dissection of the aorta is controversial. To determine the prevalence of arteriosclerotic coronary artery disease in patients with type A dissection of the aorta, we reviewed our experience in 62 patients (42 with acute dissection and 20 with chronic dissection) who underwent operation between January 1, 1986, and December 31, 1993. Among 23 patients with acute dissection who underwent coronary arteriography, 8 (34.8%) had one or more coronary artery lesions causing a greater than 50% narrowing. Among 14 patients with chronic dissection who underwent coronary arteriography, 6 (42.9%) had one or more coronary artery lesions causing a greater than 50% narrowing. There were no fatal complications associated with coronary arteriography. Four patients with acute dissection and 6 patients with chronic dissection underwent coronary artery bypass grafting at the time of operative repair of the aortic dissection, with no operative deaths. On the basis of these findings and the success of combined coronary artery bypass grafting and aortic repair, we recommend that patients with an acute type A dissection who are in stable condition and all patients with a chronic type A dissection of the aorta should undergo preoperative coronary arteriography.

Transvenous endomyocardial biopsy is now well-established as the gold standard for evaluation of possible rejection episodes after cardiac transplantation. From 1985 to August 1992, 1990 patients have undergone 193 cardiac transplantations at Barnes Hospital. One hundred eighty-three patients survived their initial hospitalization and serve as the study group. Their records were reviewed for the purposes of identifying those with tricuspid regurgitation as a complication of right ventricular endomyocardial biopsy. These patients have undergone a total of 2,960 biopsies for an average of 16.2 biopsies per patient. Over a mean follow-up period of 4.22 years, all patients have been evaluated with standard two-dimensional echocardiograms. Mild to moderate tricuspid regurgitation was very common, but was thought to be biopsy-induced only if severe and accompanied by flail components of the tricuspid valve. Twelve patients were identified with this entity at our institution. Of these, 5 had no symptoms and were receiving no diuretics, 3 had mild symptoms consisting of lower extremity edema and continued to receive diuretics, 2 had moderate symptoms, and 2 had right heart failure and anasarca refractory to medical therapy. Both of the severely affected patients subsequently required tricuspid valve replacement. We conclude that the tricuspid valve apparatus is at significant risk of injury during endomyocardial biopsy, that most patients will be minimally symptomatic due to tricuspid regurgitation when this injury occurs, and that when the injury is accompanied by severe symptoms, the likelihood of improvement with medical therapy is small.

Accessory atrioventricular (AV) pathways responsible for the Wolff-Parkinson-White syndrome have been treated successfully by surgical and radiofrequency catheter ablation techniques. In this study, we explored the feasibility of permanent chemical ablation of accessory pathways by direct injection of 100% ethanol into the canine AV groove. Right coronary artery blood flow and AV compartment pressure were measured in 5 adult mongrel dogs (part I) during injection of saline solution (10 to 15 mL) into the right AV groove. Atrioventricular groove compartment pressure increased from 1 +/- 1 to 31 +/- 12 mm Hg (p < 0.0001) and right coronary artery blood flow increased slightly from 117 +/- 17 to 138 +/- 44 mL/min (p = not significant). In 8 additional dogs (part II), 100% ethanol (10 mL) was injected into the left AV groove. After 6 weeks (n = 6) or 12 weeks (n = 2), histologic examination of the left AV groove demonstrated localized fibrous replacement of injured epicardial muscle, with only scant inflammatory infiltrate. Mild intimal fibrosis and intimal proliferation were present in the circumflex artery and its larger branches, but no significant luminal narrowing was evident. Angiograms at 12 weeks (n = 2) demonstrated no significant narrowing of the circumflex artery. In summary, injection of 100% ethanol into the AV groove is capable of locally ablating myocardial tissue, presumably including conductive tissues, while sparing the coronary arteries.

Between January 1, 1986, and December 31, 1991, 4,507 adult patients underwent cardiac surgical procedures requiring cardiopulmonary bypass. Of these patients, 3,983 patients who did not undergo operation for supraventricular tachycardia and who were in normal sinus rhythm preoperatively form the study group for the present study. Postoperatively, all patients were monitored continuously for the development of arrhythmias until the time of hospital discharge. The incidence of atrial arrhythmias requiring treatment for the most commonly performed operative procedures were as follows: coronary artery bypass grafting, 31.9%; coronary artery bypass grafting and mitral valve replacement, 63.6%; coronary artery bypass grafting and aortic valve replacement, 48.8%; and heart transplantation, 11.1%. For all patients considered collectively, the risk factors associated with an increased incidence of postoperative atrial arrhythmias (p < 0.05 by multivariate logistic regression) included increasing patient age, preoperative use of digoxin, history of rheumatic heart disease, chronic obstructive pulmonary disease, and increasing aortic cross-clamp time. Postoperative atrial fibrillation was associated with an increased incidence of postoperative stroke (3.3% versus 1.4%; p < 0.0005), increased length of hospitalization in the intensive care unit (5.7 versus 3.4 days; p = 0.001) and postoperative nursing ward (10.9 versus 7.5 days; p = 0.0001), increased incidence of postoperative ventricular tachycardia or fibrillation (9.2% versus 4.0%; p < 0.0005), and an increased need for placement of a permanent pacemaker (3.7% versus 1.6%; p < 0.0005). These data provide a basis for targeting specific patient subgroups for prospective, randomized trials of therapeutic modalities designed to decrease the incidence of postoperative atrial arrhythmias.

Splenic artery to right renal artery bypass was used successfully for surgical correction of renovascular hypertension in an elderly patient. The technique used is described.

A Doppler pulmonary artery catheter system (Doppler cardiac output monitor or DOPCOM) that continuously measures instantaneous and mean cardiac output was recently introduced. Because thermodilution (TD) flow measurements may not represent an adequate standard, the present study was designed to compare TD and DOPCOM cardiac output measurements with aortic electromagnetic (EM) flow in cardiac surgical patients. Twenty-one patients scheduled for elective coronary artery bypass grafting were enrolled in the study. Simultaneous measurement of cardiac output by all three methods was performed before cardiopulmonary bypass, after cardiopulmonary bypass with the aorta cannulated and volume intermittently infused, and after decannulation. Analysis of all data demonstrated fair TD and EM correlation (r = 0.80), with minimal bias (0.03 +/- 1.21 L/min) and a median absolute error of 0.53 L/min; DOPCOM and EM data showed moderate correlation (r = 0.64), a bias of -0.61 +/- 1.50 L/min, and a median absolute error the same as TD (0.51 L/min). However, distribution of DOPCOM values was heavily skewed by 3 patients in whom flow measurements immediately after cardiopulmonary bypass were markedly different between the DOPCOM and electromagnetometry, probably because of malposition of the Doppler transducers secondary to partial catheter withdrawal during bypass. Consistent with this theory was the finding that before CPB, the DOPCOM was significantly better than TD in predicting EM flow (median absolute error: DOPCOM, 0.12 L/min, and TD, 0.48 L/min; p = 0.04). Our data suggest that, in general, the DOPCOM shows similar precision to TD for predicting EM flow measurements, although the DOPCOM may underestimate actual flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Between January 1, 1986, and May 6, 1991, 7,884 cardiac surgical procedures requiring cardiopulmonary bypass were performed at our institution, including 672 (9.8% of adult procedures) performed in 669 patients that were associated with preoperative (n = 240), intraoperative (n = 353), or postoperative (n = 79) use of an intraaortic balloon pump. The mean age of recipients was 65.3 years (range, 16 to 89 years). Intraaortic balloon pump usage increased during the study period from 6.4% of patients (83/1,298) in 1986 to 12.7% of patients (169/1,333) in 1990. The relative distribution between preoperative (mean, 35.7%), intraoperative (52.5%), and postoperative (11.8%) insertion remained nearly constant during the study period. The overall operative (30-day) mortality for patients with preoperative, intraoperative, or postoperative insertion of the intraaortic balloon pump was 19.6%, 32.3%, and 40.5%, respectively (X2 = 16.4; p less than 0.001). Although use of the intraaortic balloon pump in the intraoperative and postoperative settings is accompanied by a favorable outcome in most patients, the high associated mortality suggests the need for earlier use of the intraaortic balloon pump or other supportive measures such as the ventricular assist device.

We have been comparing cardiac output measured with a novel Doppler pulmonary artery catheter to that measured by thermodilution and aortic electromagnetometry in cardiac surgical patients. We report here our observation of a nearly twofold increase in thermodilution cardiac output after the acute intraoperative onset of tricuspid regurgitation that was not confirmed by the novel catheter or direct measurement of aortic blood flow. We conclude that in some patients, acute tricuspid regurgitation may lessen the reliability of thermodilution cardiac output.

A simple method for rapidly achieving femoral venous cannulation is described. We have found this method to be particularly useful for femoral cannulation when the patient is in the thoracotomy position.

A 59-year-old woman had a right homonymous hemianopsia, memory impairment for five months, a nonenhancing area in the left parieto-occipital region on CT scan, and bilateral reticulonodular infiltrates on chest x-ray film. Lung biopsy findings were consistent with sarcoidosis, a clinical diagnosis of CNS sarcoidosis made, and prednisone therapy begun. She deteriorated neurologically and died. At autopsy characteristic histologic and electron microscopic features of progressive multifocal leukoencephalopathy (PML) were found. We conclude that this and other cases demonstrate an association of PML and sarcoidosis and that steroid treatment is not a precondition. We also suggest an aggressive diagnostic approach in evaluating sarcoidosis with atypical neurologic deficits.

We have developed a new method of computer image processing that allows true three-dimensional (3-D) images of the heart and great vessels to be reconstructed from standard ECG-gated two-dimensional magnetic resonance (MR) images. Contiguous 5-mm thick MR images of the thorax from the level of the cardiac apex to the aortic arch were obtained in 4 normal volunteers and 3 patients with congenital heart disease: 1 with pseudotruncus arteriosus and 1 with a ventricular septal defect, each with Eisenmenger's complex, and 1 with aortic coarctation. Each image could be obtained at up to seven different intervals throughout the cardiac cycle with ECG gating. The scanning procedure is noninvasive and requires no contrast material. Using standard software, images from each interval in the cardiac cycle were edited to isolate pertinent cardiac and great vessel structures. High-resolution 3-D reconstructions were formed for each interval by stacking the edited images. Sequential projection of 3-D reconstructions from each interval yields four-dimensional (includes time) cine views. Both 3-D and cine views can be obtained from any axis or divided in any plane to allow accurate, noninvasive assessment of cardiac and great vessel anatomy, chamber volumes, and regional and global wall motion. Noninvasive 3-D reconstruction of the heart and great vessels provides accurate anatomical data not available from standard cardiac catheterization or other noninvasive diagnostic procedures, and aids in the preoperative planning of the procedure to correct complex congenital malformations.

The use of standard electrocardiographic monitoring to detect cardiac allograft rejection has become unreliable since the advent of cyclosporine immunosuppression. Unipolar peak-to-peak amplitude analysis has been shown to be a quantitative measure of ischemic myocardial injury. This study was performed to determine if unipolar peak-to-peak amplitude analysis could accurately detect cardiac allograft rejection as determined by blinded endomyocardial biopsies. Ten adult mongrel dogs underwent heterotopic (n = 7) or orthotopic (n = 3) cardiac transplantation with placement of sutureless screw-in electrodes (Medtronic, Inc, Minneapolis, MN) on the anterior and posterior aspect of each ventricle. Postoperatively, animals were immunosuppressed for seven to ten days with cyclosporine and prednisone and then allowed to reject the transplant. Digitally processed intramyocardial electrograms were obtained daily. Endomyocardial biopsy was performed 1 week postoperatively and then at three to five day intervals for histological correlation. A unipolar peak-to-peak amplitude decline of 15% or greater occurred one to three days before the biopsy detection in 10 of 10 episodes of rejection. There were no false negatives and one false positive (although a small focal lymphocytic infiltrate was present). Thus, noninvasive unipolar peak-to-peak amplitude analysis was 100% sensitive and 90% specific in predicting and detecting cardiac allograft rejection.

Forty-nine bypasses originating from the distal superficial femoral artery or popliteal artery in 46 patients were reviewed to examine late patency, limb salvage, and factors leading to graft failure. Operations were performed because of tissue loss in 86%, rest pain in 12%, and limiting claudication in 2% of limbs. Proximal anastomosis was from the distal superficial femoral artery in 12% and the popliteal artery in 88%. Distal anastomosis was to the below-knee popliteal artery or proximal tibial vessels in 20% and the distal tibial vessels in 80%. Life-table analysis showed a primary patency rate of 83%, 62%, and 41%, at 1, 3, and 5 years, respectively. The rate of limb salvage at 6 years for all grafts was 69%. Cox proportional hazards analysis determined that stenosis of 20% or greater in the proximal superficial femoral artery before bypass was a significant risk factor for graft failure (p = 0.02) despite the presence of normal intra-arterial pressure at the site of the proximal anastomosis at the time of bypass. Long-term survival in these patients was low, with a 6-year survival rate of only 24%. Infragenicular bypasses originating from the distal superficial femoral artery or the popliteal artery can be performed with patency and limb salvage rates comparable to bypasses originating from the common femoral artery. These bypasses are more likely to fail when performed in the presence of a stenosis 20% or greater in the superficial femoral or popliteal artery proximal to the graft origin.

Blunt trauma to the popliteal artery usually results in acute arterial damage that requires urgent repair. Most blunt trauma to the popliteal artery is associated with skeletal injuries. We report a patient who had a chronic pseudoaneurysm of the popliteal artery 10 years after minor blunt trauma to the popliteal fossa. The cause of the pseudoaneurysm and suggestions for the early recognition of these arterial injuries are discussed.

Injury can occur to several of the cranial nerves during carotid endarterectomy. Among these, glossopharyngeal nerve injury is an uncommon complication because it is remote from the field of dissection in most carotid procedures. From more than 2000 carotid operations four cases of symptomatic ninth cranial nerve injury were identified. Analysis revealed that dissection cephalad to the level of the hypoglossal nerve was a common feature of each and severe functional disability can result from glossopharyngeal nerve paresis. When mobilization of this nerve and division of the posterior belly of the digastric muscle and styloid process become necessary for additional exposure, the risk of glossopharyngeal nerve injury increases. Specific recommendations are made regarding management and maneuvers to help reduce the incidence of this uncommon, yet potentially serious, complication.

The effects of ethanol and meperidine on the auditory evoked potential (AEP) to stimuli of different intensities were investigated. Sixteen normal male volunteers received ethanol, 0.8 ml/kg, 100 mg meperidine, and a placebo on different days in a double-blind study. AEPs were recorded from Fz, Cz and Pz electrode placements. The stimuli were 500 msec 1000 Hz tones at 50, 60, 70 and 80 dB sound pressure level presented in a pseudo-random sequence. Meperidine had no significant effect on AEP variables. Ethanol reduced AEP activity between 24 and 250 msec but had no effect on the sustained potential measured between 300 and 450 msec.

Spinal cord monitoring during thoracic aneurysmectomy by somatosensory evoked potentials has been criticized for its failure to measure anterior (motor) spinal cord function. We have developed a clinically applicable, noninvasive technique for intraoperative monitoring of motor evoked potentials (MEP), which allows direct functional assessment of spinal cord motor tracts during thoracic aortic occlusion. Twelve dogs underwent continuous intraoperative monitoring of MEP before, during, and after thoracic aortic cross-clamping. Motor tract response to noninvasive cord stimulation (5 to 10 mA, 0.02 msec, 4.3 H2) was recorded by subcutaneous electrodes placed along the length of the spine (T-10, L-1, and L-4). Six animals (group I) subjected to aortic cross-clamping alone demonstrated a characteristic time- and level-dependent deterioration and loss of MEP. Ischemic cord dysfunction (as determined by time from clamping to loss of MEP) progressed from the distal to the proximal cord (L-4 = 11.3 +/- 1.5 minutes; L-1 = 14.9 +/- 2.3 minutes; T-10 = 16.9 +/- 2.3 minutes; p less than 0.05 between all levels). Reperfusion of the distal aorta 20 minutes after clamping resulted in MEP return that progressed from the proximal (T-10) to distal (L-1 and L-4) cord. In another six animals (group II), distal perfusion (mean blood pressure = 95 mm Hg) was maintained for 1 hour after cross-clamping by left atrial-femoral artery bypass. Normal configuration and amplitude of MEP was maintained throughout the cross-clamping period. These data suggest that distinctive changes in MEP indicative of reversible ischemia of spinal cord motor tracts occur after aortic cross-clamping. Such ischemia begins in the most distal cord, exhibits upward progression with time, and can be prevented by maintenance of adequate distal aortic perfusion. Clinical use of MEP monitoring during thoracic aneurysmectomy may provide a method for intraoperative assessment of the adequacy of motor tract perfusion.

Anterior approaches to the renal arteries are complicated by the intervening renal veins, inferior vena cava, and abdominal viscera. We describe techniques of direct posterolateral access to both right and left renal arteries by use of an extended retroperitoneal exposure. This approach allows for grafting from the aorta or iliac artery on either side and is particularly suitable on the left side for direct retropancreatic splenorenal artery anastomosis, which is described in detail. It is also useful for distal reconstruction of branch renal arteries, renal artery embolectomy, and autotransplantation "bench surgery." We have used this approach in 28 patients with no operative deaths and two reconstructive occlusions.

Over a 7-year period, follow-up data were available on 163 patients who underwent 209 pacemaker-related operations for initial insertion or revision of previously implanted units. During the follow-up period, 16 pacemaker generator units were remoaved from 16 pacemaker generator units were removed from 12 patients solely because of the development of local skin erosion. This represents a 7.7% incidence of pacemaker generator erosion. Tree units were removed within a 3-month interval following pacemaker implantation and were associated with positive bacterial cultures, theraby indicating an infectious cause. Findings at removal of the remaining 13 pacemaker generators included extensive fibrosis with chronic inflammation, fibroblastic proliferation, and granulation tissue, which was most prominent at the site of insertion of the pacemaker lead into the pacemaker generator unit. Granulation tissue frequently led from this area to the area of skin attenuation and erythema. Inspection of the pacemaker generator units and electrodes demonstrated fluid ingress and tissue ingrowth toward the electrode due to inadequate seal mechanisms. Inadequate seal design of the pacemaker generator and electrode junction leads to tissue ingrowth with fibroblastic proliferatiog chronic inflammation, and eventual pacemaker erosion.

Fifty patients who had carotid bifurcation endarterectomy as their sole surgical procedure underwent intraoperative completion angiography by means of portable intraarterial digital subtraction angiography. All had subsequent intravenous digital subtraction angiography or duplex scanning during early follow-up. After the endarterectomy site was closed and before the wound was closed, 6 to 8 ml of contrast was injected through a 21-gauge needle while fluoroscopy was performed with a conventional C-arm. The C-arm was coupled to a Quantel IDIS Mobile Digital Subtraction Angiogram Unit (Quantel Medical Products Group, Clemmons, N.C.) for image enhancement and immediate playback. There were no postoperative deaths or neurologic complications. Abnormal radiographic results led to reopening of endarterectomy sites in eight patients, which resulted in successful correction of the defects. There was a single asymptomatic occlusion of the internal carotid artery at 3 weeks in the patient with the only false-negative result on the completion study. Intraarterial digital subtraction angiography is a safe and useful technique for intraoperative quality control of carotid endarterectomy. It provides visual images that can be easily repeated in several projections, uses small volumes of contrast, and has no timing requirements for filming and injecting.

A surgically created, totally autogenous venous valve has been devised that holds potential for the treatment of venous insufficiency. Valves were constructed from 2.7 cm long segments of canine external jugular veins. Through the use of intimal separation, folding, and suturing techniques, thin, pliable valves with an intimal lining were constructed and interposed in the canine superficial femoral vein. Fifteen valves were implanted in three groups of dogs. In group I (six dogs) the valves were immediately removed after implantation and subjected to various levels of hydrostatic pressure. In group 2 (six dogs) valves were removed after 1 week and examined for patency and competency. Group 3 animals (three dogs) were anticoagulated with subcutaneously administered heparin from implantation to removal at 7, 9, and 13 days. In group 1 valves were found to open at less than 3 cm of water and remain competent at 55 cm of water. Two of these valves subjected to 300 mm Hg pressure also remained competent. In the six group 2 dogs, two valves remained patent and competent, whereas four valves were patent but incompetent as a result of thrombus that prevented valve closure. In group 3 all valves were patent and competent at 7, 9, and 13 days after implantation. An autogenous venous valve that opens at physiologic pressures and remains competent at high pressures can be surgically created. The ability to remain competent at high pressures may give this valve an advantage over the repaired, transposed, or transplanted native venous valve in the treatment of chronic venous valvular insufficiency.