A combined approach to the noninvasive diagnosis of carotid artery occlusive disease.

A combined approach utilizing ophthalmosonometry (OSM), carotid phonoangiography (CPA), and ocular pneumoplethysmography (OPG) was applied to 31 patients with symptoms of carotid artery occlusive disease. Arteriograms were subsequently obtained in 70 of these patients, thus allowing the accuracy of each technique to be assessed in 140 carotid arteries. Both Doppler OSM and OPG correctly identified all complete occlusions of the internal carotid artery. However, greater than 50% stenoses were detected by OSM in only 52% and by OPG in 87%. Thus the cumulative accuracy in detecting hemodynamically significant lesions was 76% for OSM and 93% for OPG. The addition of CPA to OPG raised the combined accuracy of the two techniques to 98% for significant carotid lesions. The development of a regression line criterion for the OPG, in combination with CPA, permitted identification of 100% of patients with bilateral carotid artery lesions. However 75% of patients with symptomatic, ulcerating plaques were missed by all three tests, thereby emphasizing the need for angiography in appropriately symptomatic patients. The principal usefulness of noninvasive testing in evaluating patients with carotid artery occlusive disease is for: (1) asymptomatic bruits, (2) atypical, nonhemispheric symptoms, or (3) following carotid endarterectomy.

Percutaneous transluminal angioplasty in the selected management of proximal arterial occlusive disease of the lower extremities: a preliminary report.

Percutaneous transluminal angioplasty was used in the treatment of 17 segmental, arterial stenoses in 12 patients. Successful dilatation was achieved in 88% of lesions with documented hemodynamic improvement of all successful cases. The technique has been applied as the sole treatment in certain cases of isolated iliac stenosis. It also has been used to improve arterial inflow prior to more distal reconstruction, as well as to treat localized disease progression in patients with previous arterial reconstruction. It must be considered a new adjunct in the management of patients with arterial occlusive disease.

Are routine inferior vena cavograms necessary before Greenfield filter placement?

In August 1983 we began routinely studying the inferior vena cava (IVC) before placement of a Greenfield filter. We have performed 83 caval interruptions since that time, but six patients were excluded from this study because an IVC clip had been placed in three patients during other abdominal surgery, and the medical records of three others could not be retrieved. Of the remaining 77 patients, 65 (84%) had IVC venograms taken before placement of their filter. We personally reviewed 63 of these cavograms but had to accept the radiologist's reports for two studies that could not be retrieved. Ten (15%) cavograms showed abnormalities that significantly affected the placement of the filter. The most frequent abnormality was intracaval clot extending above the L3-4 interspace. Other important abnormalities were severe narrowing of the diaphragmatic IVC (two patients) and a tortuous IVC in a patient with severe scliosis. Seven (11%) additional cavograms showed unilateral iliac thrombus that would have influenced the surgical approach had a femoral approach been required. Formal preoperative cavography expedited filter placement and reduced operating time by obviating the need for intraoperative angiograms. Because 26% of the cavograms showed clinically important information, we recommend that routine IVC angiograms be taken before filter placement.

Vascular insufficiency secondary to ergotism.

A case of ergot-induced peripheral vascular insufficiency mimicking atherosclerosis is presented and the clinical symptoms with vascular laboratory evaluation and roentgenographic findings are discussed in detail. A review of the literature of the vascular complications of ergot alkaloids is presented. After considering the various therapeutic modalities employed, a conservative, but hopefully more rational, treatment for these lesions is recommended. Although uncommon, this problem always must be considered in the differential diagnosis of the young patient, especially female, who presents with visceral or peripheral arterial insufficiency.

The significance of graft diameter.

To study the influence of diameter on graft patency, an 8 mm aortoiiliac Dacron graft was implanted in on leg of 25 dogs that had liac arteries 3 to 5 mm in diameter and a 5 mm graft was placed in the other leg. In six dogs both grafts clotted within 3 months, in 10 dogs both grafts remained patient until the dogs were killed between 7 and 66 months, and in nine dogs one graft became occluded before the other. In eight of these nine animals the 8 mm graft became occluded before the 5 mm graft; only in one dog did the 5 mm graft become occluded first. When the 10 dogs with two patient grafts were killed, the 8 mm graft was found to be lined with thick, organized fibrin, whereas the 5 mm graft had a thin, smooth, glistening lining. Histologic examination confirmed that healing was more complete in the 5 mm graft. In vivo blood flow measurements in the dogs were used to compare flow rates and graft resistance in 4, 6, 8, 10, and 12 mm grafts. A given sized graft carried the same flow capacity as larger grafts until the flow rate was reached when graft resistance developed. Once resistance appeared, the graft could still triple or quadruple its flow capacity but it could not deliver the same rate of flow under the same pressure head as larger grafts. In 4 mm grafts, resistance first appeared at approximately 150 cc/min and capacity was 450 cc. In 6 mm grafts, resistance developed at 400 cc/min and capacity exceeded 1,200 cc. In 8 and 10 mm grafts, resistance was first noted at 800 and 1.400 cc/min, respectively. These studies suggest that 6 mm diameter grafts can carry the 200 cc/min or less that is measured in the human superficial femoral artery at rest, as well as the four-to sixfold increase that accompanies vigorous exercise.

Thrombogenicity of a fibronectin-coated, experimental polytetrafluoroethylene graft.

To determine if pretreatment of polytetrafluoroethylene (PTFE) vascular grafts with fibronectin (FN) increased platelet adherence to them and adversely affected their patency, we labeled autologous canine platelets with indium III-oxine and interposed a FN-coated, experimental, 4 mm inner diameter, 10 cm long PTFE prosthesis into one carotid artery of 10 dogs. An identical graft, lacking only the FN coating, was implanted as a control in the contralateral carotid artery. A second group of 10 dogs was similarly treated, but each animal received 2 grains of aspirin and 50 mg of dipyridamole (Persantine) daily, beginning 3 days before surgery and continuing for the duration of the experiment. By means of a quantitative, gamma-camera, platelet adherence to the grafts was studied for 5 days after implantation. Graft patency was assessed with the Doppler velocity meter and was confirmed by surgical reexploration when thrombosis was suspected. FN coating increased platelet adhesion to the grafts in animals untreated with aspirin by a factor of threefold to fivefold. In those animals receiving antiplatelet drugs, patency of FN-coated grafts at 5 days was significantly (p less than 0.05) higher (80%) than in untreated animals (27.2%). In addition, mean platelet deposition on the grafts in these animals was reduced compared with untreated controls. Thus although FN coating of PTFE grafts significantly increases their affinity for platelets, this effect can be effectively abolished by pretreatment with aspirin and dipyridamole.

Bacterial adherence to endothelial-seeded polytetrafluoroethylene grafts.

Since infections of an arterial prosthesis pose a serious threat to life and limb, efforts to produce a graft that is resistant to hematogenous bacteremia continue. We studied the effect of endothelial seeding on bacterial adherence to polytetrafluoroethylene grafts in a canine model. Enzymatically derived venous endothelial cells were seeded in 10 cm long, 4 mm inner diameter polytetrafluoroethylene grafts, which were then implanted as carotid interpositions opposite contralateral unseeded controls. After 4 to 8 weeks, each dog received an intravenous infusion of 3 X 10(8) radiolabeled Staphylococcus aureus. Seeded grafts had significantly fewer adherent viable bacteria than had control grafts (mean, 432 versus 989; p less than 0.05) and significantly fewer radiolabeled bacteria (mean, 2 X 10(5) versus 8 X 10(5); p less than 0.05). Seeded grafts also had significantly more thrombus-free, luminal surface area than had control grafts (mean, 72% versus 40.6%; p less than 0.05). Scanning electron microscopy and autoradiography of seeded grafts confirmed that the sites of bacterial adherence largely corresponded to accumulations of surface thrombus. In this experiment, endothelial seeding appeared to protect against bacterial adherence after a hematogenous challenge 4 to 8 weeks after implantation by reducing luminal thrombi.

Physical characteristics of implanted polytetrafluoroethylene grafts: a preliminary report.

Despite the widespread clinical use of polytetrafluoroethylene (PTFE) grafts, few reports dealing with their physical properties have appeared in the literature. In the past 20 months, 17 such grafts have been implanted into 15 patients threatened with limb loss, with an 88% immediate graft patency. Postoperatively, all patients underwent periodic evaluations; arteriograms were obtained in four. The effect of knee flexion on graft function was also studied. All grafts were found capable of withstanding cuff pressures in excess of 300 mm Hg without occlusion. With 90 degrees flexion, the grafts kinked crossing the knee joint but a pressure gradient or decrease in pulsatile blood flow did not develop. This remarkable resistance to external compression should render these grafts especially valuable for extra-anatomic bypass.

Aortofemoral bypass grafting: a reappraisal.

Aortic bypass grafting was performed in 100 consecutive patients with disabling manifestations of aortoiliac arterial occlusive disease. There were no operative deaths, graft infections, false aneurysms, or aortoduodenal fistulas. Of those patients whose superficial femoral arteries were patent, 95% had a good or excellent immediate functional result that was maintained in 89% on late follow-up. Of those whose superficial femoral arteries were occluded, 83% had a similar immediate result and 70% maintained this improvement. Graft limb patency was 89% after 36 months. Additional distal arterial reconstructions were ultimately required in 9% of all limbs, resulting in a good to excellent functional outcome for 93% of all our patients. We believe aortofemoral grafting remains the best method for the correction of aortoiliac occlusive disease.

The carotid-carotid bypass graft.

Occasional patients have multiple, branch artery occlusions of the aortic arch that preclude any of the standard extrathoracic bypass grafts. We recently treated such a patient with carotid-carotid bypass and found it to be remarkably simple and effective. This article describes the technical details of this procedure and suggests its future applications.

Impotence after kidney transplantation.

Sexual performance was evaluated in 28 men, thirty to sixty years of age, with functioning renal allografts: 13 were potent (controls), 10 had moderate sexual dysfunction, 5 had marked sexual dysfunction. Penile blood pressures, serum hormone levels, plasma zinc levels, and penile venous angiography were evaluated in search of causes of impotence. Thirteen of 15 impotent transplant patients (87 per cent) had marked abnormalities in at least one of the four areas studied. Systematic search for etiologic factors may permit specific therapy for impotence, which occurred in 54 per cent of the 28 kidney transplant patients analyzed.

Role of the vascular diagnostic laboratory in the evaluation of male impotence.

Penile systolic pressures, penile volume waveforms, and postischemic reactive hyperemia were measured in 106 patients (38 potent and 68 impotent). With such testing the vascular laboratory can clearly identify those impotent patients in whom penile blood flow is normal and who would not benefit from direct arterial surgery. Unfortunately, abnormal results give no assurance that ischemia is responsible for a given patient's impotence and a multimodal approach is necessary to further evaluate such patients.

A comparison of digital subtraction angiography and noninvasive testing in the diagnosis of cerebrovascular disease.

Among the 1,892 patients who underwent cerebrovascular digital subtraction angiography at our hospital over the past 18 months, there was a subgroup of 34 patients (65 carotid arteries) for whom noninvasive cerebrovascular test results and standard cerebral arteriograms were also available. These patients were reviewed retrospectively and the ability of both methods to detect hemodynamically significant lesions, defined as a greater than 50 percent reduction in the diameter of the carotid artery, was determined using the arteriograms as the "gold standard." Noninvasive cerebrovascular tests had a sensitivity of 81 percent, a specificity of 95 percent, a positive predictive value of 92 percent, a negative prediction value of 88 percent, and an overall accuracy of 89 percent. Digital subtraction angiography had a sensitivity of 84 percent, a specificity of 92 percent, a positive predictive value of 88 percent, a negative predictive value of 89 percent, and an overall accuracy of 89 percent. If the four cases of hemodynamically significant stenosis of the carotid siphon not detected by digital subtraction angiography had been considered as false-negatives, its sensitivity would have been reduced to 72 percent. In patients with hemispheric cerebral ischemia, we found noninvasive cerebrovascular tests neither necessary nor cost-effective. Digital subtraction angiography, on the other hand, often provided definitive diagnostic information in such patients if the intracranial circulation was well defined and the extracranial lesion corresponded to the patients' symptoms. Noninvasive cerebrovascular testing was the safest and most cost-effective technique for screening patients with asymptomatic bruits, atypical, nonhemispheric cerebral symptoms, and those who have undergone carotid endarterectomy. If the noninvasive cerebrovascular test result was positive or equivocal, digital subtraction angiography was performed to localize the responsible lesion and exclude carotid occlusion.

Data management in the vascular laboratory.

As the clinical workload in the vascular laboratory increases and as the demand for additional documentation by hospital oversight committees and outside agencies grow, the need for computerized data management will become obvious. Although there are no generic, broadly applicable software programs to automate the laboratory's operations, applications can easily be developed using any of the current database programs to meet the needs of most laboratories. Fortunately, the intense competition in the microcomputer industry has recently made very powerful systems that are capable of providing the necessary computing support increasingly affordable. Such systems can be very simple or incredibly complex depending on the available local expertise and each laboratory's specific needs. In addition to facilitating the laboratory's daily operations, such a system will inevitably expedite the implementation of the laboratory's quality assurance program and will maximize utilization of existing personnel. This type of cost-effective solution to the ever-increasing demand for service will become increasingly important in maintaining the laboratory's fiscal viability. Although the prospects of undertaking such a task might seem daunting, especially to the computer novice, it is important to begin. Keep the system simple, at first, and allow it to develop as local expertise and confidence develop. The only prospect more frightening that sitting down to develop a computerized system for managing the laboratory's data, is the prospect of trying to continue without one!

Segmental volume plethysmography in the diagnosis of lower extremity arterial occlusive disease.

Over a 24 month period, segmental limb systolic pressures (SLP), pulse volume recordings (PVR) and bi-planar arteriograms were obtained for 202 lower extremities. The SLPs proved unsatisfactory for the localization of arterial disease and are presently employed only to assess the extent of limb ischemia. Bases on simple, qualitative criteria, the thigh PVR was graded as "normal" or "abnormal" and correctly predicted the presence or absence of hemodynamically significant aortoiliac disease in 95% of limbs. It there was a greater than 25% increase in the amplitude of the calf PVR relative to he thigh, patency of the superficial femoral artery was correctly identified in 97% of lower extremities. The limited accuracy of SLP alone in differentiating iliac and femoral artery occlusive disease, especially when present in combination, emphasizes the necessity of including some type of waveform analysis in the routine evaluation of patients with lower extremity arterial insufficiency.

Semi-quantitative photoplethysmography in the diagnosis of lower extremity venous insufficiency.

A new standardization device has permitted calibration of the Photopulse Adaptor, thus, making venous photoplethysmography (PPG) a more accurate, semiquantitative technique. Using this device, we studied 10 normal volunteers and 151 extremities in 69 symptomatic patients We also developed a formula for calculating the slope of the venous recovery curve which took into consideration the degree of venous emptying as well as the duration of venous recovery. The PPG was "abnormal" if there was no measurable venous emptying despite effective calf contraction or if the calculated venous recovery rate (VRR) exceeded 2.0 mm/sec. VRR clearly separated normal extremities (1.28 mm/sec) from those in which venous reflux was present (3.34 mm/sec). If we had relied on measurement of venous recovery time (VRT) alone, 30% of hour normal volunteers and 52% of our symptomatic patients would have been misdiagnosed. We feel that these modifications have made PPG a more accurate technique less subject to the vagaries of arterial inflow, and thereby more valuable to the vascular surgeon in elucidating venous pathophysiology and following the results of his therapy.