Biomedical subjects

R C Darling

Publications and source records attributed to R C Darling.

At least 109 records · Page 6Linked to original sources

PubMed1987

Neurologic sequelae with internal carotid artery occlusion.

A retrospective review of the clinical course surrounding internal carotid artery occlusion (ICO) was undertaken in 97 patients with 106 instances of ICO. No neurologic symptoms could be attributed to more than half of the ICOs. Of the 52 symptomatic occlusions, 19 (37%) were associated with transient ischemic attacks and 33 (63%) with fixed strokes. Only 10% of all patients had permanent disabling neurologic sequelae. There was no correlation between development of neurologic symptoms and the side of the ICO, the presence or severity of contralateral carotid artery disease, or other risk factors. Women, however, were twice as likely as men to develop a fixed stroke with ICO. Seventy-six of these patients underwent reconstructive carotid surgery. Although there was a high rate of abnormal intraoperative findings with electroencephalographic monitoring (32 of 62 cases), with the use of intraoperative shunts there was no increase in the postoperative stroke complication rate (1.8%). These data suggest that the concern that ICO leads to serious fixed neurologic deficits may be overestimated, and that its presence does not adversely affect carefully performed contralateral carotid endarterectomy.

Aged↗

PubMed1987

Reoperation for aortofemoral graft limb occlusion: optimal methods and long-term results.

To determine optimal methods of reoperation, experience with 157 secondary procedures for unilateral aortofemoral graft limb occlusion in 110 patients during a 16-year period was reviewed. In earlier years, inflow was reestablished by direct replacement of the graft limb or entire graft (11%); more recently, graft limb thrombectomy has been used most frequently (68%) with equal success, durability, and less morbidity. Femorofemoral grafts from the patent contralateral graft limb were employed in 18% of patients, usually those in whom thrombectomy was not attempted. Thrombolytic therapy (3%) appears to offer little advantage, is time-consuming, and occasionally causes significant complications. In addition to reestablishment of inflow, most patients also required revision of the femoral anastomosis to improve profunda femoris runoff; this was usually best accomplished by short segmental extension of the graft limb to the more distal deep femoral artery. Concomitant femoropopliteal bypass was done in 32% of patients and is indicated when preoperative angiography or specific intraoperative findings suggest inadequate profunda femoris outflow. An aggressive approach to reoperation appeared justified by long-term results (mean follow-up 37 months). Despite the need for repetitive reoperation in 26% of patients (two to five reoperations), graft limb patency was ultimately maintained in 78% and limb salvage achieved in 67% of patients, with an operative mortality rate of only 1.9%.

Adult↗

PubMed1986

Use of the splenic and hepatic arteries for renal revascularization.

During a 16-year period at the Massachusetts General Hospital 77 patients underwent 79 procedures (29 hepatorenal bypasses, 50 splenorenal arterial anastomoses) for treatment of renovascular hypertension, renal preservation, or both. The procedure was chosen primarily to avoid a diseased or scarred aorta in 41, to allow a staged approach to bilateral renal artery stenoses or multiple vascular lesions in 17, as a "lesser operation" for five poor-risk patients, for complex problems including trauma, mycotic aneurysm, aortic dissection, thoracoabdominal aneurysm, and renal artery aneurysm in five, and as the procedure of choice in 11 patients. The perioperative mortality rate was 6% for the 77 patients studied. No hepatic dysfunction was seen. Deterioration of renal function occurred on three occasions but only in patients with bilateral simultaneous repair. Cure or improvement of hypertension was achieved in 52 of 63 patients and renal function preserved or improved in 67 of 77 patients. Long-term functional results remain good during follow-up periods up to 14 years. Our experience indicates that use of the hepatic or splenic artery may provide a safe and largely successful alternative for renal revascularization in selected circumstances.

Follow-Up Studies↗

PubMed1986

Preoperative evaluation of abdominal aortic aneurysms by computed tomography.

A prospective, preoperative study was conducted of 50 electively repaired abdominal aortic aneurysms comparing the CT and angiographic findings with those described at surgery. CT demonstrated all 50 aneurysms and correctly identified their proximal extent in relation to the takeoff of the renal arteries in 47 patients (94%), while angiography detected 48 aneurysms (96%) and their correct relation to the renal arteries in all (100%). CT correctly identified 40 (98%) of 41 patients with two renal arteries, but only two (29%) of seven with three and none of two patients with four arteries. Common iliac artery involvement or lack thereof was accurately predicted in 42 (84%) of the 50 patients and internal iliac artery aneurysms found in one (33%) of three patients. It was concluded that CT is not sufficiently accurate for documenting location and patency of the renal arteries to allow its routine substitution for angiography in patients undergoing preoperative assessment of abdominal aortic aneurysms.

Aged↗

PubMed1986

Mural degeneration in the glutaraldehyde-tanned umbilical vein graft: incidence and implications.

After discovering an aneurysm in a glutaraldehyde-tanned umbilical vein (GTUV) graft that resulted in graft thrombosis, we reevaluated all patients from our institution who had GTUV grafts implanted for more than 2 years. Of 60 patients identified, 14 of 15 patients with patent grafts were recalled and had either digital subtraction or standard angiographic studies. Angiographic changes in the grafts were graded on a scale of 0 to 3, from normal (grade 0) to frank aneurysmal degeneration (grade 3). Eight grafts (57%) had frank aneurysmal (grade 3) changes, and three other grafts (21%) had preaneurysmal (grade 2) changes. Only one graft was angiographically normal. GTUV grafts undergo aneurysmal degeneration in a significant percentage of implants. Symptomatic aneurysms have presented with thrombosis and limb-threatening ischemia as well as rupture. GTUV aneurysms should be treated by complete graft resection, as segmental resection of diseased portions of grafts resulted in metachronous aneurysm recurrence. Because of the high incidence of GTUV degeneration, the clinical indications for the use of GTUV grafts should be seriously reevaluated, and we recommend that all patients with patent GTUV grafts for more than 2 years be evaluated for the presence of aneurysmal degeneration.

Aldehydes↗

PubMed1985

Determination of cardiac risk by dipyridamole-thallium imaging before peripheral vascular surgery.

To evaluate the severity of coronary artery disease in patients with severe peripheral vascular disease requiring operation, we performed preoperative dipyridamole-thallium imaging in 54 stable patients with suspected coronary artery disease. Of the 54 patients, 48 had peripheral vascular surgery as scheduled without coronary angiography, of whom 8 (17 per cent) had postoperative cardiac ischemic events. The occurrence of these eight cardiac events could not have been predicted preoperatively by any clinical factors but did correlate with the presence of thallium redistribution. Eight of 16 patients with thallium redistribution had cardiac events, whereas there were no such events in 32 patients whose thallium scan either was normal or showed only persistent defects (P less than 0.0001). Six other patients also had thallium redistribution but underwent coronary angiography before vascular surgery. All had severe multivessel coronary artery disease, and four underwent coronary bypass surgery followed by uncomplicated peripheral vascular surgery. These data suggest that patients without thallium redistribution are at a low risk for postoperative ischemic events and may proceed to have vascular surgery. Patients with redistribution have a high incidence of postoperative ischemic events and should be considered for preoperative coronary angiography and myocardial revascularization in an effort to avoid postoperative myocardial ischemia and to improve survival. Dipyridamole-thallium imaging is superior to clinical assessment and is safer and less expensive than coronary angiography for the determination of cardiac risk.

Aged↗

PubMed1985

The fate of polytetrafluoroethylene grafts in lower limb bypass surgery: a six year follow-up.

The success of lower limb bypass surgery depends, in the major part, on the availability of autologous saphenous vein as the most satisfactory arterial substitute known to date. Although various prosthetic conduits, used in the absence of saphenous vein, have shown promising success on short term follow-up, more long-term comparative data are required for adequate assessment. This study analyses, by life table method, the results of 134 infra-inguinal bypass grafts using polytetrafluoroethylene (PTFE) over a 6 year period. The results reconfirm the superior long-term patency of vein bypasses compared with such prosthetic grafts. Analysis suggests that, while PTFE may give acceptable results in the immediate and short-term follow-up period, 6 year patencies approach 20-30 per cent.

Arteries↗

PubMed1985

Innominate artery lesions: problems encountered and lessons learned.

Although unusual, innominate artery lesions may present challenging problems. To classify the wide spectrum of problems requiring operation and elucidate certain principles of management, a series of 71 patients undergoing operation for innominate artery problems over a 20-year period was reviewed retrospectively. Occlusive disease (37 patients) was most common, usually presenting with neurologic or ocular symptoms. Other lesions included innominate aneurysm (three), aortic dissection involving the innominate artery (three), traumatic injuries (five), tracheoinnominate fistula (10), anomalous origin or tortuosity causing tracheal compression (six), involvement in mediastinal tumor or scar (six), and thromboembolus (one). The type of operative repair and mortality rate varied with the nature of the lesion. Overall 38 patients underwent transsternal repair, whereas 12 had extrathoracic bypass, 16 resection and oversewing, and five a pexy procedure. For occlusive disease, direct repair via median sternotomy gave best long-term results with an acceptable mortality rate (3.4%). Shunting was not required. Extrathoracic grafting proved safe but less durable and should be reserved for high-risk patients or special circumstances.

Arterial Occlusive Diseases↗

PubMed1985

Selection of patients for preoperative coronary angiography: use of dipyridamole-stress--thallium myocardial imaging.

To identify patients likely to benefit from preoperative coronary angiography, a method utilizing pharmacologically induced coronary vasodilatation in conjunction with serial thallium 201 myocardial perfusion imaging was investigated. Fifty-four patients admitted for elective aortic or femoropopliteal procedures were studied. There were no cardiac ischemic complications in 32 patients with normal scans or persistent defects (scar). In contrast, 7 of 15 patients with thallium redistribution (ischemia) on pre-operative scanning had perioperative ischemic events, including one death and two acute infarcts. An additional seven patients with positive scans (redistribution) underwent coronary angiography prior to vascular surgery; surgically important two- or three-vessel disease was confirmed in all. Dipyridamole-thallium imaging facilitates selection of the subset of truly high-risk patients in whom preoperative coronary angiography may be warranted.

Aged↗

PubMed1984

Isolated popliteal segment v tibial bypass. Comparison of hemodynamic and clinical results.

Clinical and hemodynamic results of isolated popliteal segment, tibial, and sequential bypass grafts were compared in a retrospective review. Results were good with vein grafts to either an isolated segment or infrapopliteal vessel, with five-year patency rates of 71% and 72%, respectively. Prosthetic grafts performed poorly in both groups, and sequential grafts appeared advantageous in such circumstances. Average ankle pressure increased 49 mm Hg following successful isolated segment grafts. Although less than with patent tibial or sequential grafts, improvement was sufficient to relieve rest pain in all instances and heal ischemic lesions or local amputations in all but four patients. If an adequate vein is available and a good tibial vessel exists, distal grafting may be elected, particularly if advanced ischemic lesions demand restoration of pulsatile flow to the foot. If such conditions are not present, isolated segment grafting will give highly satisfactory results.

Aged↗

PubMed1984

Transcutaneous oxygen tension in selection of amputation level.

The utility of transcutaneous oxygen tension measurements in selection of a reliable amputation level was evaluated. Measurements were made at the proposed level of amputation in 37 patients, 22 of whom underwent major limb amputation and in 15 amputation was confined to the forefoot or toes. In patients with successful amputation healing, mean transcutaneous oxygen tension on the anterior skin surface was 50 +/- 8 mm Hg (index 0.79 +/- 0.1 mm Hg). In contrast, patients with failure of healing had a mean transcutaneous oxygen tension of 22 +/- 16 mm Hg (index 0.32 +/- 0.19 mm Hg) (p less than 0.001). Measurements on the posterior or plantar skin surface and posteroanterior differences provided even greater separation between success and failure groups, with no overlap of transcutaneous oxygen tension values or index. Transcutaneous oxygen tension measurement is easily obtained and noninvasive, and can be applied to all patients irrespective of Doppler signals, noncompressible vessels, or painful lesions. Transcutaneous oxygen tension appears to predict successful healing with accuracy, and should be a useful addition to clinical judgment in selection of optimal amputation level.

Adult↗

PubMed1984

Renal artery injury from a Fogarty balloon catheter.

A variety of complications secondary to thromboembolectomy with balloon catheters have been described. The present report describes an unusual and previously unreported complication following retrograde thrombectomy of an occluded limb of an aortofemoral graft. The variety of arterial injuries and technical misadventures attributable to balloon catheters are briefly discussed, and suggestions are made for avoiding the particular problem encountered in the patient described.

Blood Vessel Prosthesis↗

PubMed1983

Femoropopliteal and tibioperoneal artery reconstruction using human umbilical vein.

We used 99 human umbilical vein (HUV) grafts for femoropopliteal or tibioperoneal artery reconstruction in 94 patients. Results were calculated according to the life-table method for several categories possibly influencing graft patency. For above-knee v below-knee distal anastomosis, there was no difference in patency or limb-salvage rates at 30 months. Comparison of good and poor runoff situations disclosed similar 30-month graft patency rates, but significantly better limb-salvage rates among patients with good runoff. Primary revascularization fared significantly better than secondary procedures in terms of patency and limb salvage. We found no significant differences between HUV and polytef (polytetrafluoroethylene) for above-knee anastomoses or good runoff situations. However, patency and limb salvage were better for HUV use in below-knee anastomosis and poor runoff situations. The HUV may offer advantages in long-term patency and limb salvage in selected patients.

Aged↗

PubMed1983

Femoropopliteal graft failures. Clinical consequences and success of secondary reconstructions.

We examined 188 failed femoropopliteal grafts during a 16-year period to evaluate the clinical consequences of graft failure and success of secondary revascularization procedures. In limbs with grafts placed for claudication, conditions of 9% with failed grafts remained improved despite graft occlusion, 67% returned to preoperative status, and 24% showed worsened ischemia. One third of claudicants with failed grafts underwent secondary procedures. Ultimately, only 7% of failed grafts in claudicants resulted in amputation, and overall risk of limb loss in patients undergoing operation for claudication alone was low (2%). After failure of grafts performed for limb-salvage indications, 21% of limbs were still improved, and 79% reverted to limb-threatened status, more than half of the limbs undergoing subsequent reoperation. Overall, secondary attempts at reconstruction appeared justified. Although the five-year patency rate of such grafts was only 31%, limb salvage was achieved in 52%, with relatively low morbidity and mortality.

Aged↗

PubMed1983

Aggressive surgical management of popliteal artery aneurysms.

One hundred fifty-nine patients with 244 popliteal aneurysms underwent 167 reconstructive procedures. Patients were divided into those with asymptomatic aneurysms, those with acute ischemia secondary to thrombosis or embolism, those with claudication secondary to chronic thrombosis or embolism, and those with local symptoms referable to the aneurysm itself. Patients who underwent successful revascularization were considered to have good early results. Patients with asymptomatic aneurysms had uniformly good results (97.2 percent) as opposed to those presenting with acute (70.7 percent) or chronic symptoms (83.8 percent). Similar statistically significant differences were seen when patients with thrombosis (71.7 percent) or embolism (81.3 percent) were compared with asymptomatic patients. Analysis of late results indicates that if an initial good result was obtained, the late patency rate was independent of type of presentation. Late results were affected by type of conduit employed where life table analysis showed the superiority of saphenous vein over Dacron prosthesis. At 5 year follow-up, 77.2 percent of all saphenous veins were patent whereas only 29.5 percent of Dacron prostheses remained patent.

Acute Disease↗

PubMed1983

Factors affecting patency of femoropopliteal bypass grafts.

A 16 year review of femoropopliteal bypass grafts identified five factors with significant influence on long term patency. Most important was the nature of the graft itself, with vein grafts having superior long term performance as compared to a variety of prosthetic grafts. Arteriographic runoff, indications for operation, site of the distal anastomosis and prior femoropopliteal operation had a major influence on long term patency of prosthetic grafts but rather minimal effects on the patency of autogenous vein grafts. The influence of several variables proved cumulative, leading to a favorable subset of patients in whom prosthetic grafts may approach long term performance of vein grafts. Differences in such key variables is a major contribution to the widely differing patency rates of previous studies and must be carefully controlled in any future prospective studies.

Aged↗

PubMed1982

Deep venous thrombophlebitis following aortoiliac reconstructive surgery.

One hundred patients undergoing elective aortic surgery were scanned prospectively for development of deep venous thrombosis (DVT). The incidence of DVT in this population was 13%. Eleven patients showed only calf vein thrombosis on venography, whereas two had occlusive iliofemoral thrombus. The correlation between venous Doppler ultrasound and venography was 80%. More importantly, Doppler examination correctly identified both patients with occlusive thrombus. Fibrinogen scanning was associated with a false-positive rate of 31%. Only one patient suffered a nonfatal pulmonary embolus. Fibrinogen scanning has an unacceptably high false-positive rate; however, Doppler ultrasound will identify significant occlusive thrombus without a high false-positive rate. The low incidence of pulmonary emboli does not warrant such definitive measures as prophylactic vena caval interruption.

Adult↗

PubMed1982

Transluminal angioplasty of the iliac and femoropopliteal arteries. Current status.

Transluminal angioplasty for the management of atherosclerosis obliterans has been performed in 160 patients for 100 iliac and 98 femoropopliteal lesions. The procedure was performed percutaneously except in eight patients in whom operative exposure was required. Angioplasty was technically successful in all 100 iliac artery lesions. There was hemodynamic and clinical improvement in 92 lesions. The procedure was technically successful in 84 of the 98 femoropopliteal artery lesions with hemodynamic improvement in 74 and clinical improvement in 78. There were ten complications directly related to the angioplasty and six related to the arteriographic procedure. Cumulative patency rates for the angioplasties were 92% and 75% at three years for iliac and femoropopliteal lesions, respectively. These promising results suggest that transluminal angioplasty has a definite role in the management of atherosclerosis obliterans of iliac and femoropopliteal arteries.

Adult↗