Dipyridamole thallium imaging in patients being considered for vascular procedures.

We routinely performed intravenous dipyridamole thallium imaging and resting radionuclide ventriculography on 190 patients being considered for elective vascular procedures. Patients with thallium redistribution underwent coronary arteriography. Patients in group 1 (n = 78) had clinical evidence of coronary artery disease, and patients in group 2 (n = 112) had no history or electrocardiographic evidence of coronary artery disease. The frequency of thallium redistribution was not significantly different in the two groups (45% in group 1 and 46% in group 2). Coronary arteriography identified severe three-vessel or left main disease in eight patients (10%) in group 1 and 16 patients (14%) in group 2. Selection of patients for dipyridamole thallium imaging prior to vascular reconstruction should be based on whether or not documentation of the extent of coronary artery disease would influence therapy rather than on clinical indicators of coronary disease.

Comparison of continuous-wave Doppler imaging, oculopneumoplethysmography, and the cerebrovascular Doppler examination.

Previous reports of continuous-wave Doppler imaging have combined that technique with periorbital Doppler studies. In the present report, 75 patients with findings suggestive of cerebrovascular insufficiency were evaluated using continuous-wave Doppler imaging, oculopneumoplethysmography (OPG-G) and the cerebrovascular Doppler examination (CDE). Each test was interpreted independently. Doppler imaging had an overall accuracy of 85%, with a 68% accuracy in identifying 50-70% stenoses and a 69% accuracy in identifying high-grade stenoses (greater than 70%) and occlusion. OPG-G had an overall accuracy of 85%, with a 55% sensitivity for 50-70% stenoses and an 89% sensitivity for high-grade stenoses and occlusion. The CDE had an overall accuracy of 84% and a 50% sensitivity for stenoses of 50-70% and an 88% sensitivity for high-grade stenoses and occlusion. As an independent technique, continuous-wave Doppler imaging achieves an overall accuracy comparable to that of OPG-G or the CDE. Its sensitivity to high-grade stenosis and occlusion, however, is less than that of the other techniques. Since CDE and OPG-G had a 94% sensitivity to carotid occlusion and a combined sensitivity to high-grade stenoses and occlusion of 88% and 89%, respectively, their combined use with Doppler imaging offers sensitivity to and differentiation of stenoses from occlusion.

Aortofemoral bypass grafting: Microvel.

One hundred seventy-five patients underwent elective aortofemoral bypass during the years from 1976 to 1979. One hundred eighteen of these patients received a knitted double velour prosthesis (Microvel) and the remainder received standard knitted Dacron. All patients had been followed for a minimum of 12 months. Early graft thrombosis occurred in three limbs, and these were restored by reoperation for 100 per cent patency at discharge from the hospital. The operative mortality was three patients (1.7%). Complications included myocardial infarction (three/one death), renal failure (one/one death), respiratory failure (one/one death), cerebrovascular accident (four), and superficial wound infection (five). Late complications were infrequent, but included seven graft limb occlusions in six patients (3.4%), and one graft infection, one ureteral obstruction, and one false aneurysm. Among the 256 symptomatic extremities, claudication was completely relieved in 199 (78%) and substantially improved in an additional 48 (18.5%). Hemodynamic assessment with arm/ankle or arm/high thigh indices improved in parallel with symptomatic relief. Thus, only nine (3.5%) symptomatic extremities failed to improve with the proximal reconstruction, requiring distal reconstruction or amputation. The authors remain advocates of aortofemoral grafting with end-to-end proximal anastomosis and hooding of the distal anastomosis over the profunda origin for most aortoiliac occlusive diseases. Our recent experience with double velour graft and this technique have been very satisfactory.

Evaluation of cerebrovascular Doppler examination and oculopneumoplethysmography in a clinical perspective.

The cerebrovascular Doppler examination (CDE) and oculopneumoplethysmography (OPG-Gee) were compared in a single population group with no statistically significant difference found between the 2 studies. There appeared to be an advantage to combinant testing, for when the results of the 2 studies were concordant there was an accuracy of 94% and a false negative rate of 8%. Clinical correlation was available in 96% of the patients, providing adequate evidence to support the adjuvant role of non-invasive screening in the evaluation of symptomatic individuals. The percentage of false negative studies and the incidence of ulcerative disease make a diagnostic role impractical at present. For the asymptomatic individual, the diagnostic role of non-invasive screening seems justified. The false negative studies in the present series were confined to those vessels with 50-70% stenoses, which are difficult to assess angiographically and may be better characterized by hemodynamic evaluations.

Distal reconstruction following aortobifemoral bypass grafting: predictability by early hemodynamic result.

Controversy exists concerning the usefulness and accuracy of immediate postoperative ankle-arm indexes in predicting the need for distal reconstructive procedures following aortobifemoral bypass grafting. To evaluate this concept, preoperative, immediate postoperative, and late postoperative ankle-arm indexes were calculated for 20 patients (70% had combined aortoiliac and superficial femoral disease) undergoing aortobifemoral grafting during a 12-month period. Twenty-three (58%) of the 40 limbs had greater than or equal to 0.1 (m 0.43) increase in ankle-arm index immediately after operation, of which 15 (65%) had a further increase of greater than or equal to 0.1 in late postoperative ankle-arm index. Seventeen (42%) had a decrease, < 0.1 increase, or no change in ankle-arm index immediately after operations, but ten (59%) of these had an ultimate increase of greater than or equal to 0.1 in late postoperative ankle-arm index Thirty-eight (95%) of the extremities were either asymptomatic or greatly improved. These data indicate that 1) secondary distal reconstructive procedures are infrequently necessary after aortobifemoral grafting; 2) significant changes in ankle-arm indexes occur after the immediate postoperative period; 3) the majority of limbs in which the ankle-arm index decreases, is unchanged, or insignificantly increaed early postoperatively will ultimately have a significant rise in ankle-arm index late postoperatively; and 4) immediate postoperative ankle-arm index is not an accurate or reliable predictor of the need for immediate distal reconstructive procedures after aortobifemoral grafting. The authors' current approach towards this problem is to delay secondary distal reconstructive procedures, depending upon patients' symptoms and late hemodynamic results.

Results of ophthalmosonometry and supraorbital photoplethysmography in evaluating carotid arterial stenoses.

A total of 263 patients underwent either periorbital ophthalmosonometry (Doppler ultrasound) or a combination of ophthalmosonometry and supraorbital photoplethysmography (SOPPG) to determine the presence or absence of a hemodynamically significant lesion (occlusion or greater than 50% reduction in lumen diameter). There were 522 vessels studied with Doppler ultrasound and 272 vessels with a combination of the two modalities. The tests were correlated with carotid arteriography to determine their accuracy. Overall accuracy of the Doppler ultrasound examination was 95%. A normal Doppler ultrasound examination was obtained in 367 vessels and arteriography confirmed the absence of a hemodynamically significant lesion in 93%. Of 155 vessels with an abnormal Doppler examination, 149 (96%) were proven on arteriography to have hemodynamically significant lesions. The Doppler ultrasound examination had a high incidence of false-negative examinations (26%) in those vessels that were between 50% and 99% stenotic, however. The SOPPG alone had a high incidence of false-positive examinations (19%); however, in 155 vessels with a normal SOPPG, 98% were proved to have no hemodynamically significant lesion. The combination of Doppler ultrasound and SOPPG was highly accurate in identifying patients with hemodynamically significant lesions. Of 97 vessels with such lesions, 96 (99%) had either an abnormal Doppler ultrasound examination or an abnormal SOPPG. In 240 vessels with concordant results of the Doppler ultrasound and SOPPG, the presence or absence of a hemodynamically significant lesion was accurately predicted in 235 (98%).

Value of arterial pressure measurements in the proximal and distal part of the thigh in arterial occlusive disease.

A prospective study was carried out comparing two techniques of segmental arterial pressure measurements of the leg to detect, localize and quantify regional arterial occlusive disease. The measurement of pressures of the proximal and distal parts of the thigh with the narrow cuff technique permitted correct anatomic localization of aortoiliac, femoropopliteal or combined disease in 78 per cent of diseased extremities, including all limbs with isolated aortoiliac or femoropopliteal disease. A single wide cuff arterial pressure measurement of the thigh correctly localized arterial obstructions in only 19 per cent of diseased extremities. Although a wide cuff is associated with less artifactual elevation in measured arterial pressure at the thigh, this advantage is outweighed by the limitation of diagnostic accuracy in localizing segmental arterial occlusive disease. We recommend that segmental arterial pressure measurements of the limb be made at four levels on the lower extremity, including arterial pressures of the proximal and distal parts of the thigh to achieve maximal diagnostic accuracy.

Noninvasive assessment of collateral blood flow of the cerebral hemisphere by Doppler ultrasound.

Directional flow in the frontal artery, a terminal branch of the ophthalmic artery, was assessed nonivasively by Doppler ultrasound druing brief digital compression of the ipsilateral common carotid artery in 62 patients. Directional frontal artery flow during carotid compression was compared with mean distal internal carotid back pressure measured at subsequent carotid endarterectomy. Mean carotid back pressure in 28 patients with normal frontal artery flow direction during carotid compression, 68 +/- 14 millimeters of mercury, was significantly higher than that observed in 24 patients in whom frontal artery flow was completely obliterated and ten in whom frontal artery flow was reversed. Distal internal carotid back pressure exceeded 48 millimeters of mercury in all patients with normal frontal artery flow direction during carotid compression. Conversely, carotid back pressure was below 41 millimeters of mercury in all but one patient in whom frontal artery flow was obliterated or bliterated or reversed during carotid compression. The results of this study indicate that Doppler ultrasound assessment of frontal artery flow direction during simultaneous carotid compression provides a rapid, sale noninvasive estimate of the adequacy of collateral hemispheric circulation.

Doppler ultrasound and supraorbital photoplethysmography for noninvasive screening of carotid occlusive disease.

Doppler ultrasound and supraorbital photoplethysmography were 95 per cent accurate in identifying or excluding significant carotid obstruction in 156 vessels of seventy-six consecutive patients undergoing arteriography. Plethysmography was more sensitive but less specific than Doppler ultrasound. These technics provide simple, rapid, and accurate detection of significant carotid occlusive disease.

Doppler cerebrovascular examination: improved results with refinements in technique.

Doppler ultrasonic assessment of extracranial carotid occlusive disease has been modified to decrease the incidence of false positive and negative diagnoses. The technique, which assessed directional flow in the frontal artery and the influence of sequential compression of each temporal, infraorbital, facial and common carotid artery, was performed on 152 vessels visualized by contrast arteriography. Presence or absence of significant (greater than 50%) stenosis or occlusion of the internal carotid artery was identified correctly in 150 vessels (98.7%). Inasmuch as the classic temporal artery compression test only detected 39 of the 61 abnormal Doppler studies (64%), the more complete examination is recommended for screening patients for significant carotid artery obstruction.

Thromboembolic complications of angiography for peripheral arterial disease: prospective assessment by Doppler ultrasound.

The incidence of thromboembolic arterial complications related to percutaneous angiography done for patients with arterial disease was assessed in 101 cases (105 procedures). There were 2 instances of anterior tibial artery obstruction and 3 of a decline in ankle pressure greater than 20 mmHg in patients with preexisting leg arterial disease. No patient evidenced symptoms of the complications. This incidence of thromboembolic accident, detected by Doppler ultrasound, is significantly less than those incidence rates noted previously, although the reasons for this difference have not yet been established.

Value of segmental limb blood pressures in predicting results of aortofemoral bypass.

The efficacy of segmental limb blood pressure measurements, assessed noninvasively by Doppler ultrasound, in predicting the result of aortofemoral reconstruction was evaluated in fifty-two extremities with varying extent of aortoiliac and more distal arterial occlusive disease. Three prognostic correlates were analyzed: (1) preoperative proximal thigh/arm pressure index (TPI); (2) preoperative pressure gradient between adjacent leg segments (proximal thigh, above-knee, below-knee, and ankle), normally less than 30 mm Hg; and (3) early postoperative increase in the ankle/arm pressure index (API). After aortofemoral bypass, forty-one limbs (79 per cent) were asymptomatic or improved and eleven were unimproved. The mean TPI in extremities benefiting from aortofemoral bypass, 0.82 +/- 0.17 (+/-1SD) was significantly less than that of unimproved limbs, 1.01 +/- 0.09 (p less than 0.01). Aortofemoral bypass was beneficial in all twenty limbs with normal leg pressure gradients. Conversely, six of twenty-five legs with one abnormal gradient and five of seven with two abnormal gradients failed to improve. The postoperative increase in API was 0.1 or more in all forty-one improved extremities and was less than 0.1 in all eleven failures. Although eleven of thirty-two limbs (34 per cent) with arteriographic evidence of combined aortoiliac and subinguinal occlusive disease were not improved after proximal bypass, the result of operation could not be predicted from the angiographic pattern or severity of distal disease. Segmental limb blood pressures provide useful predictive indices of the efficacy of aortofemoral bypass and the potential need for more distal reconstruction in multisegmental disease.

Noninvasive ultrasonic carotid angiography: prospective validation by contrast arteriography.

Pulsed ultrasonic images of the carotid bifurcation in 82 vessels of 43 patients were compared independently with contrast arteriograms for stenosis (by percentage quartiles) or occlusion of the internal carotid artery. All 14 occluded vessels were identified correctly by ultrasound but were visualized on repeat examination. Estimation of percentage stenosis on ultrasonic images agreed with the quartile determination by contrast arteriography in 35 of 68 (51 percent) vessels and was within one quartile of correct interpretation in 48 of 68 (71 percent). The interpretative error of grading stenosis of ultrasonic images was due to vascular wall calcification which inhibited ultrasound transmission. This limitation was overcome by sound spectral (sonographic) analysis of distal internal carotid flow velocity which allowed estimation of stenosis within one quartile of that determined by contrast arteriography in 46 of 47 (98 percent) vessels.

Postoperative deep vein thrombosis in the lower extremity amputee: A prospective study with Doppler ultrasound.

The incidence of postoperative venous thrombosis and pulmonary embolism was assessed in 87 patients undergoing 96 major lower extremity amputations for ischemia. Prospective surveillance for deep leg vein thrombosis was carried out by Doppler ultrasound in 35 patients. There was no instance of major leg vein thrombosis and only one episode of a small non-fatal pulmonary embolus in a patient suffering trauma to the amputation stump after discharge from the hospital. This study suggests that clinically significant venous thromboembolism following current techniques of lower extremity amputation is not as common as previously reported. Doppler ultrasound is the most suitable technique for surveillance of venous thrombosis in these patients.

An index of healing in below-knee amputation: leg blood pressure by Doppler ultrasound.

Preoperative Doppler ultrasonic assessment of below-knee (BK) arterial signals and systolic blood pressures was performed on 50 patients undergoing 53 BK amputations for advanced ischemia. No patient was excluded from initial BK amputation unless gangrene at that level or severe joint contracture was present. Failure of healing of the BK amputation occurred in all five limbs with an undetectable Doppler arterial signal (and thus pressure) below the knee. Failure of amputation occurred in four of 16 limbs with detectable arterial signals and BK pressures less than 70 mm. Hg. Healing occurred in all 32 limbs with BK pressures greater than 70 mm. Hg. The differences in healing between these three groups are highly significant (p less than 0.005). This study suggests that Doppler ultrasonic assessment of BK arterial signals and pressures may be a simple hemodynamic correlate of healing of a BK amputation. Absence of a detectable arterial signal below the knee may be an indication for initial above-knee (AK) amputation in advanced ischemia.