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Biomedical subjects

R C Darling

Publications and source records attributed to R C Darling.

At least 127 records · Page 7Linked to original sources
PubMed1982

Aortofemoral graft for multilevel occlusive disease. Predictors of success and need for distal bypass.

Results of aortofemoral reconstruction of 181 consecutive patients with multilevel occlusive disease were reviewed and correlated with possible predictors of outcome. Overall, 74% of patients attained satisfactory relief of ischemic symptoms with proximal operation alone. Forty-six patients (26%) had an unsatisfactory result, 31 (17%) of whom underwent distal bypass grafts. Of 42 variables studied, 12 achieved statistical significance as predictors of outcome, and multivariate analysis identified five factors an independent indicators. Factors documenting hemodynamically significant inflow disease were associated most strongly with a good result. Several noninvasive laboratory variables were found helpful, particularly in assessing the hemodynamic compensation of distal disease. While no single variable reliably indicated the definite need for distal grafting, careful consideration of important factors together with the clinical situation will aid the surgeon in selection of the small group of patients best treated by synchronous aortofemoral and femoropopliteal grafts.

Adult↗
PubMed1982

Modification of the Haemonetics Cell Saver for optional high flow rate autotransfusion.

Intraoperative autotransfusion is a technique well-suited to major vascular surgery. It is most effective when salvage and reinfusion of shed blood can be accomplished at flow rates compatible with the degree of hemorrhage encountered in both elective and emergency procedures. Appropriate equipment modifications can render commercially available autotransfusion devices safer and more effective in the management of intraoperative blood loss. The Cell Saver, a device which concentrates and washes salvaged red blood cells, is limited in its potential as an autotransfusion device because of its slow reinfusion rate. A modification was devised which expands the flow capabilities of the Cell Saver and allows rapid reinfusion of autologous whole blood. The modified blood circuit has been employed in 10 major vascular cases with favorable results, thus demonstrating its efficacy in the management of massive hemorrhage during vascular repair. Guidelines for the safe and effective use of the modified unit are stressed.

Adult↗
PubMed1982

Comparative analysis of vein and prosthetic bypass grafts to the isolated popliteal artery.

The effectiveness of prosthetic femoropopliteal bypass grafts to salvage limbs and maintain long-term patency in lower extremities with a limited outflow tract is controversial. To evaluate the results of prosthetic grafts and compare them with the results of vein bypass grafts in limbs with a limited outflow tract, we reviewed a 15-year experience with 65 grafts to an isolated popliteal artery segment. Fifty-one grafts were performed with autogenous saphenous vein, and 14 grafts utilized a prosthetic conduit. The indication for surgery was rest pain in 22 patients and actual tissue necrosis in 43 patients. The operative mortality rate was 3.4%. The average preoperative absolute ankle blood pressure was 48 mm Hg. Following a successful bypass, an average increase of 45 mm Hg was noted. The mean intraoperative blood flow was 70 ml/min. The superior performance of autogenous vein grafts was quite marked, with a 5-year cumulative patency of 65.4 +/- 8.5% as compared with only 17.1 +/- 10.1% for prosthetic grafts. The limb salvage rate for the entire group was 69% at 5 years. These data show the efficacy of isolated segment femoropopliteal artery grafts in achieving long-term limb salvage and stress the superiority of vein grafts over prosthetic grafts in this location.

Adult↗
PubMed1982

Femoropopliteal composite bypass grafts: current status.

Controversy continues regarding the best arterial substitute for femoropopliteal reconstruction if an adequate length of autogenous saphenous vein is not available. To evaluate the role of composite grafts as an alternate vascular conduit, we have analyzed our experience with 39 femoropopliteal composite grafts as compared with a similar group of 79 below-knee prosthetic reconstructions. The 5-year cumulative patency rates for composite and prosthetic reconstructions to the distal popliteal artery were not statistically different (38 +/- 9% and 31 +/- 8%, respectively). The amount of vein relative to prosthesis did not appear to influence late patency. Both alternate reconstructive methods were significantly inferior to the 73 +/- 3% 5-year patency rate of autogenous vein bypass grafts. Based on this experience, we have abandoned the use of composite grafts for primary femoropopliteal reconstruction, since currently available prosthetic grafts appear to have similar long-term function.

Blood Vessel Prosthesis↗
PubMed1981

Comparison of above-knee and below-knee anastomosis in femoropopliteal bypass grafts.

Experience with 555 femoropopliteal reconstructions was reviewed to evaluate the optimal location of the distal anastomosis. Autogenous vein was employed in 347 (63%) grafts and various prosthetics in 208 (37%). Vein grafts demonstrated marked superiority in late patency (73% at five years) vs prosthetic grafts (35% at five years). Below-knee (BK) anastomosis resulted in slightly better long-term patency in the vein graft group. In contrast, above-knee (AK) anastomosis was clearly preferable when prosthetic grafts were employed, particularly in patients with poor runoff or limb-threatening ischemia. The incidence of major amputation was greater following failure of BK grafts, reflecting the fact that a greater proportion of such grafts were done for limb salvage. However, failure of BK grafts did not appear to alter the level of amputation as compared with failed AK grafts.

Amputation, Surgical↗
PubMed1981

Intermittent aortic-graft obstruction secondary to anastomotic aneurysms.

Diagnosis of anastomotic aneurysms is usually suggested by simple palpation of a pulsatile mass on physical examination. Diagnosis may be more difficult, and clinical appearance more unusual, for those aneurysms occurring in an intra-abdominal location. This article reports an unusual manifestation of bilateral iliac-artery false aneurysms, ie, intermittent obstruction of aortic-graft blood flow. Femoral pulses were absent and significant peripheral ischemia present with the patient's legs extended. Femoral pulses returned to normal with the patient's legs flexed. Perianastomotic fibrosis, the mass effect of the false aneurysms, and possible kinking of the partially disrupted suture line with tensing of the psoas muscle on extension of the legs are possible causes of the intermittent obstruction to blood flow. The varied clinical manifestations and general principles of operative repair of anastomotic aneurysms are described.

Aneurysm↗
PubMed1981

Arteriovenous fistula following lumbar disc surgery.

Injury to the aorta, vena cava and iliac vessels is a recognized hazard of lumbar disc surgery (1-4). Haemorrhage may be manifest at the time, or postoperatively false aneurysm or arteriovenous fistula occurs. Four cases of arteriovenous fistula, 2 with associated false aneurysm, are described. Presentation varied between immediately postoperatively and 8 years later. In none of these injury suspected at the time of surgery.

Adult↗
PubMed1981

The limitations of polytetrafluoroethylene in the reconstruction of femoropopliteal and tibial arteries.

During a three year period, 100 patients underwent femoropopliteal or tibial polytetrafluoroethylene bypass grafts. The indication for operation was limb salvage in 75 patients. Limb salvage was achieved in 63 of 75 patients. The patency rate at 30 months for those with above-knee grafts was superior to that for those with below-knee bypasses. Grafts done in good runoff situations resulted in better patency rates than bypasses in poor outflow situations. Our results suggest that reinforced expanded polytetrafluoroethylene grafts appear to be acceptable substitutes for limb salvage when a vein is not available. However, autogenous vein bypass grafting remains our preferred method of femoropopliteal and tibial reconstruction, especially when the distal anastomosis must be constructed below the knee. Whether or not polytetrafluoroethylene is better than other current graft materials is still not known.

Blood Vessel Prosthesis↗
PubMed1981

The value of intraoperative monitoring using the pulse volume recorder during peripheral vascular reconstructive operations.

Despite precautionary measures, occasional intraoperative technical problems are encountered during vascular procedures. Early detection and correction at the time of initial operation afford the best opportunity for long term success of vascular reconstruction. From early 1978 to the middle of 1979, more than 400 vascular reconstructive procedures were monitored intraoperatively using the pulse volume recorder, a type of air plethysmography. In at least 15 instances, the pulse volume recorder was deemed instrumental in detecting an intraoperative technical misadventure. In all instances, the technical problem was corrected before the patient left the operating room. Intraoperative monitoring with the pulse volume recorder is a useful method to complement physical examination and angiography in the immediate evaluation of the results of arterial reconstructive procedures. Routine use could decrease technical complications and early graft failures in peripheral vascular reconstructive operations.

Aged↗
PubMed1980

A comparison of the use of cephalothin and oxacillin in vascular surgery.

A randomized trial comparing two prophylactic antibiotics in vascular surgery was reviewed retrospectively. Two hundred thirty-two patients were given cephalothin sodium, and 168 patients were given oxacillin sodium. The overall incidence of wound infection was 1.5%; there was only one prosthetic graft infection in 346 patients in whom prosthetic material was used. There was no significant difference in wound infection between the groups. When postoperative infection in other areas was considered, however, it appeared that cephalothin was a more suitable antibiotic for treatment of these infections despite its use prophylactically. Although this trial was uncontrolled, the low overall incidence of wound and graft infection would appear to support the use of prophylactic antibiotics in vascular surgery.

Blood Vessel Prosthesis↗
PubMed1980

Oculopneumoplethysmography: its relationship to intraoperative cerebrovascular hemodynamics.

The oculopneumoplethysmography (OPPG) test has been proposed as an effective method to identify significant carotid artery stenoses. To evaluate the clinical relevance of OPPG testing performed without carotid compression, the results of the preoperative OPPG studies, intraoperative pressure gradient measurements, and intraoperative "stump" pressure determinations were correlated retrospectively with the severity of the carotid lesions. Patients with positive OPPG test results had a mean pressure gradient of 44 mm Hg, whereas those patients with negative results had a mean gradient of 20 mm Hg. Of the patients with true-positive OPPG test results, 94% (29/31) had lesions causing at least 70% diameter reduction. However, overall accuracy of OPPG testing in this series was only 63% (33/52), as 81% (17/21) of the patients with false-negative OPPG test results also had tight lesions. Without carotid compression, OPPG testing was not useful in predicting intraoperative stump pressure. The OPPG test reflects a balance between the severity of the carotid stenosis and the adequacy of compensatory collateral flow. A positive OPPG test result is reliable in identifying those patients at greatest risk from their carotid arterial lesion. Although a negative OPPG test result does not exclude a tight stenosis, it does provide information with regard to its hemodynamic significance.

Angiography↗
PubMed1980

Coarctation of the abdominal aorta: current options in surgical management.

Coarctation or hypoplasia of the abdominal aorta is a rare cause of life-threatening hypertension. In most cases the mechanism of hypertension is elevated blood renin levels secondary to associated renal artery stenosis. Medical control of the hypertension is often difficult, and thus patients usually require renal artery revascularization combined with aortic bypass or replacement early in life. Current surgical management should optimize the use of autogenous methods of renal artery reconstruction including saphenous vein aortorenal bypass, splenorenal arterial anastomosis, hepatorenal saphenous vein bypass, and renal autotransplantation. In selected patients the reconstruction can be staged by correction of the renal artery stenosis and postponement of definitive repair of the aortic coarctation until it becomes hemodynamically significant.

Adolescent↗
PubMed1980

Relationship of intraoperative EEG monitoring and stump pressure measurements during carotid endarterectomy.

Continuous electroencephalographic (EEG) monitoring has been generally accepted as the most sensitive detector of cerebral ischemia and need for an intraluminal shunt during carotid endarterectomy. More recently, internal carotid artery stump pressure has been proposed as a simpler and equally reliable indicator of possible inadequate cerebral perfusion. In this study, stump pressure measurements and EEG changes were compared in 80 carotid endarterectomies. The mean stump pressure for patients with ischemic EEG changes was 58 mm Hg, vs 66 mm Hg for those without EEG alterations (not statistically significant). Eleven of 17 patients with definite ischemic EEG changes had stump pressure greater than 59 mm Hg, a value generally equated with adequate cerebral perfusion. EEG interpretations and stump pressure predictions did not agree in 18 of 80 patients (22.5%). Stump pressure measurements should be used with caution as the sole monitor of cerebral ischemia and need for intraluminal shunting.

Blood Pressure↗
PubMed1979

Relationship of muscle surface pH to noninvasive hemodynamic studies in arterial occlusive diseases.

To examine the possible relationship between Doppler pressures (DP) and pulse volume amplitude (PVR) with muscle surface pH (pHm), we studied 20 patients before, during, and after arterial reconstruction. The mean pHm for the claudication, rest pain, and ischemic gangrene groups differed from a control group and from each other. The pHm varied directly with DP and PVR for the 20 patients as a whole. After reconstructive surgery, improvement in pHm seemed to precede changes in DP and PVR in six patients with combined segment disease. Although pHm correlates generally with DP and PVR, it is invasive. Therefore, pHm should not be used as a routine screening test. Whereas DP and PVR may reflect the anaerobic activity of peripheral tissue, they may be less prompt than pHm in responding to acute changes in blood flow.

Arteriosclerosis↗
PubMed1979

Variable manifestations of vascular injury during lumbar disk surgery.

Major vascular injury is an unusual but well-recognized complication of lumbar disk surgery. Clinical manifestation of such injuries may be extremely variable. Isolated arterial laceration is most common, with early manifestation due to retroperitoneal hemorrhage. There are often few external signs of blood loss, however, and the diagnosis may not be recognized initially. Formation of an arteriovenous fistula or false aneurysm produces even fewer early signs, and diagnosis is often delayed for weeks or years. Six cases are described that illustrate the full spectrum of acute and chronic manifestations of such injuries. Two cases of acute hemorrhage due to arterial trauma were seen; one case was recognized intraoperatively and one in the recovery room. In four cases arteriovenous fistulae developed and were diagnosed from eight hours to eight years postoperatively. Two cases also had associated false aneurysms, one the probable source of pulmonary emboli and one the principal manifestation of the vascular injury.

Abdomen↗
PubMed1979

Intraoperative autotransfusion in major vascular surgery.

The use of intraoperative autotransfusion provides a safe and cost-effective means of salvaging operative blood loss and reducing or eliminating the use of stored homologous bank blood with its inherent difficulties and risks. The risk of disease transmission or various reactions is minimized. Autotransfusion provides a readily available, more physiologic, and at times life-saving source of blood for patients with rare blood types or patients in whom time does not permit adequate cross-matching. This technique is acceptable to most sects of Jehovah's Witnesses, who normally refuse homologous blood. Our experience during the past six years with autotransfusion in major vascular surgery reveals a mean slavage equivalent to five units of blood loss, and avoidance of using any bank blood in almost half of elective patients. No significant problems occurred due to hemolysis, coagulation abnormalities, or particulate/air emboli, nor any morbidity or mortality specifically related to autotransfusion. We conclude that wider and more frequent use of autotransfusion technics is appropriate.

Adult↗