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Biomedical subjects

R C Darling

Publications and source records attributed to R C Darling.

At least 73 records · Page 4Linked to original sources
PubMed1994

Clostridial aortic graft infection.

Aortic graft infection represents one of the most formidable challenges encountered by the vascular surgeon. Current principles of treatment are based on experience primarily derived from infection with Staphylococcus and enteric bacteria. Anaerobic prosthetic infection is a case event. Infection with Clostridium has heretofore been reported only twice. An additional case of clostridial infection of an aortic prosthesis is presented with review of the literature. Its clinical significance and management are discussed.

Aged↗
PubMed1994

The durability of different reconstructive techniques for atherosclerotic renal artery disease.

PURPOSE: Among various surgical techniques for renal artery reconstruction (RAR), anatomic aortorenal bypass has been the preferred standard. Yet concern regarding origin of the bypass from a diseased aorta and desire to avoid a major aortic operation in these patients who are often at poor risk has led to increasing use of extraanatomic bypass grafting, particularly hepatorenal and splenorenal bypass. This study was conducted to compare the safety and long-term performance of these different techniques of renal artery reconstruction. METHODS: We reviewed a 15-year (1976 to 1991) experience with 323 surgical RAR performed in 285 patients with atherosclerotic renovascular disease. Long-term patency and survival rates were analyzed by life-table methods. Variables potentially affecting early failure of the RAR and perioperative and late mortality rates were examined by Cox proportional hazards models. RESULTS: Diffuse atherosclerosis characterized the patients' clinical profile. Clinically evident coronary artery disease was present in 54% of patients, and some degree of renal insufficiency was present in 60%. Ninety-five percent of patients had hypertension with poor control of hypertension seen in 50%. Aortic disease necessitated combined aortic grafting and RAR in 43% of the study group. Various techniques of RAR were used as follows: endarterectomy or patch angioplasty, 8.5%; extraanatomic bypass grafting, 37% (hepatorenal, 62; splenorenal, 52; iliorenal, 7); and aortorenal bypass grafting, 54% (native aorta, 34; combined aortic graft and RAR, 140). Early failure of the RAR occurred in 5% of cases, and the operative mortality rate for the entire cohort was 5.6%. Median follow-up duration was 9.4 years. A comparison of early and late patency for the major types of RAR revealed equivalent (p = 0.44) performance of aortorenal and extraanatomic bypass grafting. Perioperative complications occurred more frequently (p < 0.02) in patients undergoing combined operations. The cumulative 5-year survival rate for all patients was 75%. CONCLUSIONS: Because extraanatomic bypass grafting can provide long-term results equivalent to aortorenal bypass grafting, the choice among techniques for RAR in patients with diffuse atherosclerosis should be based on both technical and operative safety considerations, rather than adherence to aortorenal bypass grafting as an inherently superior technique.

Aged↗
PubMed1994

Presentation and patterns of aortic aneurysms in young patients.

PURPOSE: Although aortic aneurysm (AA) is primarily a disease of older age groups, younger (< 51 years) patients infrequently are admitted requiring AA surgery. We sought to compare the characteristics of these patients with those of a randomly selected group of older patients with AA. METHODS: We identified 26 patients with AA (group I) under age 51 (mean age 44.8) treated surgically between 1977 and 1993, after excluding patients with acute aortic dissection, traumatic pseudoaneurysms, and ascending or arch aneurysms, and compared them with 75 randomly selected patients with AA between the ages of 65 and 75 (mean age 70.3) who were surgically treated during the same time period (group II). RESULTS: Prevalence of hypertension, diabetes, coexisting heart, kidney, or occlusive peripheral vascular disease was similar between the two groups, and familial aneurysm rates and sex distribution did not differ significantly. More patients in group I had symptoms at the time of presentation (46% vs 6.7%, p < 0.001), and they also had larger AAs (6.9 cm vs 6.0 cm, p = 0.01). Definable causes of aneurysmal disease, such as Takayasu's, Cogan's, and Marfan syndromes, were more common among the young patients (23% vs 0%, p = 0.01), but most (77%) young patients did not have an identifiable syndrome associated with their aneurysm disease. Group I had a marked shift toward proximal aneurysms, defined as involvement of juxtarenal, suprarenal, or thoracoabdominal aorta (46% vs 18% in group II, p < 0.01). This difference persisted even when aneurysms associated with the above syndromes were excluded from consideration (p = 0.02). Cigarette smoking was much more common among the young patients (83% vs 51% in group II, p < 0.01). Smoking in group II was associated with more extensive aneurysm disease (p = 0.04). CONCLUSIONS: Aneurysmal disease presenting in the young adult is more likely to be symptomatic and associated with more proximal aortic involvement than aneurysmal disease in older patients. Smoking appears to play an important role in the pathogenesis of aneurysmal disease in the young patient and was associated in our study with more proximal aneurysms among older patients. A subgroup of patients at risk for early and aggressive aneurysm disease is suggested by these data.

Adult↗
PubMed1994

Can the deep femoral artery be used reliably as an inflow source for infrainguinal reconstruction? Long-term results in 563 procedures.

PURPOSE: Historically, most infrainguinal bypasses originated from the common femoral artery. In spite of sporadic reports of the use of the deep femoral artery as an inflow source, its durability has not been critically reviewed. METHODS: From 1977 to 1994, 2829 infrainguinal reconstructions have been performed. Of these, 563 (20%) procedures have been performed with the deep femoral artery used as the inflow source. The indication for operation was limb salvage in 91.5% of cases. Four hundred eleven procedures were performed with use of the saphenous vein in situ, 48 were performed with partial in situ vein, and 75 were performed with excised (translocated) vein (29 other). When the deep femoral artery was relatively disease free, it was accessed through a lateral or standard inguinal approach. Reasons given for the use of the deep femoral artery were inadequate vein length, concomitant inflow procedures, prior groin dissections, and occluded superficial femoral artery. RESULTS: The 1- and 5-year secondary patency rates for all bypasses with the deep femoral artery were 90.4% and 76.9%, respectively, as compared with 88% and 73.3% for common femoral artery-based bypasses. Sixty-five patients (11.5%) had concomitant inflow procedures. All patients were monitored with serial noninvasive examinations, and data were collected from the vascular registry. Only eight patients (1.6%) required further inflow reconstructions for salvage of bypasses. CONCLUSIONS: The hemodynamically unobstructed deep femoral artery is a reliable and durable inflow source for patients requiring infrainguinal bypasses. Its patency rates are comparable to those of the common femoral artery-based reconstructions in our experience.

Femoral Artery↗
PubMed1994

Carotid endarterectomy can be safely performed with acceptable mortality and morbidity in patients requiring coronary artery bypass grafts.

BACKGROUND: Patients undergoing the placement of coronary artery bypass grafts (CABG) with hemodynamically significant carotid artery lesions pose a difficult problem for both cardiac and vascular surgeons. Despite numerous studies, there has been no consensus of opinion as to the proper management of these patients. In numerous series, the combined mortality and perioperative stroke rates in concomitant carotid endarterectomy and CABG procedures have ranged from 8% to 40%. This has made many surgeons consider staging these procedures. METHODS: Retrospective analysis of patients undergoing combined carotid endarterectomies and CABG from 1980 to 1993 were reviewed. Two hundred six procedures were performed in 189 patients. Seventeen patients had bilateral carotid endarterectomy performed with CABG. The average age of our patient population was 66 years, with 123 being male and 66 being female. Seventy-five percent of the patients were asymptomatic with the remainder having transient ischemic attacks, amaurosis fugax, or prior stroke. RESULTS: Operative mortality was 2%, with three of four patients dying of cardiac failure and one of a stroke. A temporary neurologic deficit was seen in 2% of patients, and a permanent neurologic deficit was seen in 2 of 206, or 1%. Thirty shunts were used in this series, mostly in patients with contralateral carotid occlusion. All procedures were performed under general anesthesia with full invasive monitoring. One patient was re-explored for bleeding, and one patient had a temporary hypoglossal palsy. A total of 203 cases had the arteriotomies closed primarily, and 3 required patches. CONCLUSION: In our experience, simultaneous carotid endarterectomy and CABG can be performed with an acceptable mortality and morbidity and does not appear to put the patient at an increased risk. Staging of these procedures may not be necessary in most cases.

Aged↗
PubMed1994

Retroperitoneal approach for bilateral renal and visceral artery revascularization.

Revascularization for renal and visceral arterial occlusive disease has traditionally been performed via a transperitoneal approach. Exposing these arteries transperitoneally is often difficult, however, and may require extensive medial visceral rotation. An alternative is a left retroperitoneal approach for renal and visceral arterial revascularization, including procedures involving the right renal artery. Over the past 7 years, a total of 186 such procedures have been performed using this approach. Of 30 that involved primarily the celiac and mesenteric arteries, 20 were completed with a bypass graft and 10 with transaortic endarterectomy. Of 156 procedures performed for renal arterial occlusive disease or aneurysmal disease extending above the renal arteries, 32 were treated with transluminal endarterectomy, 21 were treated with bilateral bypasses, and 72 were treated with unilateral bypass. Concomitant aortic endarterectomy or graft replacement was performed in 110 of this group. Operative mortality was 3.3%. Reconstructions were followed-up (for 1 to 76 months) with serial duplex and renal flow ultrasonography scans. One thrombosis developed in a renal artery bypass. We conclude that the left retroperitoneal approach may conveniently be used to reconstruct the celiac artery, superior mesenteric artery, and both renal arteries. These reconstructions may be performed with either an endarterectomy or bypass technique. In particular, the need to revascularize the right renal artery should not be regarded as a contraindication to using a left retroperitoneal approach.

Adolescent↗
PubMed1994

Increased limb salvage by the use of unconventional foot amputations.

PURPOSE: Limb salvage in the presence of ischemic foot necrosis requires revascularization followed by debridement or partial foot amputation. Necrosis extending beyond the toes and metatarsal heads may require the use of unconventional types of amputations. METHODS: Over a 15-year period 2105 ischemic limbs were treated with infrainguinal revascularization. In 98 cases, extensive foot necrosis was than managed with amputations, including 59 modified Chopart, 14 Lisfranc, 17 Pirogoff and 8 Syme amputations. Patients were not allowed to bear weight for several days to weeks. RESULTS: Skin flap necrosis in 14 cases was managed successfully by debridement and skin grafting. Ambulation required the use of a "clamshell" prosthesis and foot spacer. The overall limb salvage rate in this group was 84% (82 of 98). In general, the modified Chopart amputation most frequently produced ambulatory limb salvage and is technically easier to perform than a Syme amputation. Patient satisfaction and long-term ambulatory function was highest with the modified Chopart. CONCLUSION: Ischemic foot necrosis extending beyond the limits of conventional transmetatarsal amputation need not be treated with major amputation. This requires the surgeon to be well versed in the use of less common types of partial foot amputations. Acceptable limb salvage and good functional results may be attained by the motivated patient and surgeon with the use of these procedures in the revascularized limb.

Activities of Daily Living↗
PubMed1994

Carotid endarterectomy for unstable and compelling neurologic conditions: do results justify an aggressive approach?

PURPOSE: In a retrospective study the outcome of 70 carotid endarterectomies (CEA) in 68 patients with neurologically unstable conditions or anatomically compelling findings on carotid angiography was examined to more accurately identify patients who might benefit from CEA in this setting. METHODS: Out of a total of 1734 CEAs performed from 1978 to 1992, five groups of patients were selected: group A, stroke in evolution with tight stenosis (n = 5); group C, crescendo transient ischemic attacks (CTIA) continuing despite heparin (n = 14); group D, CTIA (above criteria) ceasing with heparin (n = 21); and group E, anatomically compelling situation on carotid angiography (n = 13). Data collected included preoperative and postoperative Neurologic Event Severity Score (NESS), CHAT classification, arteriosclerosis risk factors, demographics, and long-term overall and transient ischemic attack/stroke-free survival rates. RESULTS: Risk factors and demographics were similar in all groups. By NESS criteria the conditions of 97.3% of patients in the neurologically unstable groups A to C were improved or stabilized after operation, with one deterioration (2.7%). All patients in group B either stabilized or improved. In group D, one patient's NESS deteriorated, resulting in 3.5% overall morbidity rate and no deaths for groups A to D. Follow-up showed an overall survival rate by Kaplan-Meier analysis equivalent to a matched control population, with 85% alive at 5 years. The cumulative TIA/stroke-free survival rate at 5 years was 75%. CONCLUSIONS: In this retrospective series, CEA performed for compelling or unstable neurologic findings carried low morbidity and mortality rates. Early aggressive surgical therapy of neurologically unstable patients may be warranted because our results improved on the anticipated natural history of the conditions studied. Further clarification of proper patient selection is necessary before this principle can be applied broadly.

Adult↗
PubMed1994

Carotid endarterectomy in awake patients: its safety, acceptability, and outcome.

PURPOSE: The purpose of this study was to determine the safety and efficacy of performing carotid endarterectomy procedures with the patient receiving cervical block anesthetic. METHODS: Over the last 14 years, 654 carotid endarterectomy procedures were performed with patients receiving regional anesthetic. Intraluminal shunts were placed on demand, if neurologic changes with clamping of the carotid artery developed in the patient. During the same period, 419 cases were done with the patients receiving general anesthetic. Choice of anesthetic was based on surgeon and patient preference. RESULTS: In the regional anesthetic group the indications for operation included transient ischemic attack (311), asymptomatic hemodynamically significant stenosis (146), amaurosis fugax (106), stroke (86), restenosis (3), and aneurysm (2). Shunts were used in 46 of 654 cases (7%). Conversion from regional to general anesthetic was required in seven patients (1.1%). The operative mortality rate was 0.76% (5 of 654). Permanent nonfatal neurologic deficits occurred in 0.76% (5 of 654), and temporary neurologic deficits occurred in 1.07% (7 of 654). CONCLUSIONS: On the basis of these results, we believe regional cervical block anesthetic is an acceptable option to the routine use of shunts performed with the patient receiving general anesthetic during carotid endarterectomy. In addition, the ability to continuously assess the awake patient receiving cervical block may contribute to a decrease in perioperative stroke and mortality rates while simplifying functional cerebral monitoring during carotid endarterectomy.

Adult↗
PubMed1993

Familial carotid body tumors: incidence and implications.

Carotid body tumors may occur sporadically (90%) or in a familial pattern (10%). One third of the patients with familial disease have bilateral tumors. We report the case of a patient with bilateral carotid body tumors and a strong family history of such tumors. Details of his evaluation and treatment are reviewed. Relatives of patients with carotid body tumors should be examined carefully, and any suspicious neck mass should be appropriately investigated.

Carotid Arteries↗
PubMed1993

Aortic replacement for abdominal aortic aneurysm in elderly patients.

Improvements in the operative mortality and morbidity rates in elective aortic replacement, which are largely a result of refinements in surgical technique and perioperative management, have allowed a more aggressive approach in the treatment of abdominal aortic aneurysm (AAA) in elderly patients. To evaluate this approach, we reviewed the records of 116 patients 80 years of age and older (range: 80 to 93 years) who consecutively underwent aortic replacement for AAA. Seventy-seven patients underwent elective aortic replacement with 8 complications and a 3% operative mortality rate (2 of 77). Emergent aortic replacement was performed in 39 patients (14 with symptomatic nonruptured AAA and 25 with ruptured AAA) with 12 complications. In this nonselective subset, there were eight deaths, for an operative mortality rate of 20% (symptomatic 14%, ruptured 24%). In comparison, 780 patients less than 80 years of age underwent aortic replacement during the same time period. Within this group, 622 patients who were treated on an elective basis had a similar operative mortality (2%) as did patients 80 years of age and older. On the basis of these results, we believe that elective aortic replacement in elderly patients is justified and can be achieved with low operative mortality and morbidity rates. We suggest that the chronologic age of the patient should not deter aortic replacement.

Aged↗
PubMed1993

Is the iliac artery a suitable inflow conduit for iliofemoral occlusive disease: an analysis of 514 aortoiliac reconstructions.

PURPOSE: The aorta is the conventional inflow source for reconstructions in patients with aortoiliofemoral occlusive disease. In patients with unilateral iliac or femoral disease, femoral-to-femoral bypasses have been used but with less favorable patency rates. The purpose of this study is to evaluate the performance of the unobstructed iliac artery as an inflow source for ipsilateral, contralateral, or bilateral reconstructions in iliofemoral occlusive disease. METHODS: Over the past 6 years 322 reconstructions have been performed with the iliac artery as the donor vessel. Patients were evaluated for proximal hemodynamically significant lesions by augmented pullout pressures during aortography. Patients who had balloon angioplasty were excluded. RESULTS: Results were compared with 192 patients who underwent conventional aortodistal bypass operation for occlusive disease during the same period. Both groups were similar in risk factors, age, sex, and indications for operation. For the iliac group the operative mortality rate was 1.6%, and the 30-day patency rate was 97%, similar to those in the aortic group (3.6% and 95%, respectively). Cumulative patency rates at 5 years by life-table analysis were 82% for iliac artery inflow and 77% for aortic inflow reconstructions. CONCLUSIONS: Our experience suggests that an unobstructed iliac artery is a reasonable inflow source for reconstructions in iliofemoral occlusive disease. The long-term patency rate is comparable to aortodistal bypasses and superior to other extraanatomic bypasses.

Aorta, Abdominal↗
PubMed1993

Sequencing of cDNA from 50 unrelated patients reveals that mutations in the triple-helical domain of type III procollagen are an infrequent cause of aortic aneurysms.

Detailed DNA sequencing of the triple-helical domain of type III procollagen was carried out on cDNA prepared from 54 patients with aortic aneurysms. The 43 male and 11 female patients originated from 50 different families and five different nationalities. 43 patients had at least one additional blood relative who had aneurysms. Five overlapping asymmetric PCR products, covering all the coding sequences of the triple-helical domain of type III procollagen, were sequenced with 28 specific sequencing primers. Analysis of the sequencing gels revealed only two nucleotide changes that altered the structure of the protein. One was a substitution of threonine for proline at amino acid position 501 and its functional importance was not clearly established. The other was a substitution of arginine for an obligatory glycine at amino acid position 136. In 40 of the 54 patients, detection of a polymorphism in the mRNA established that both alleles were expressed. The results indicate that mutations in type III procollagen are the cause of only about 2% of aortic aneurysms.

Adult↗
PubMed1993

Outcome following blunt vascular trauma of the upper extremity.

Blunt trauma to the upper extremity may cause extensive vascular damage in addition to severe musculoskeletal injury. Over a 5.5-year period, 17 patients with a total of 23 arterial injuries were treated. Diagnosis was made in 16 patients before surgery by physical and Doppler ultrasonographic examination. Angiography performed in ten patients assessed the extent of injury. Associated orthopedic injuries were present in 11 patients and neurologic injury in 16. At surgery, 21 of 23 arterial repairs required autologous vein. The initial limb salvage rate was 76%. Four patients underwent above-elbow amputation because of progressive sepsis and myonecrosis. A fifth underwent delayed amputation at 7 months due to loss of limb function. Neurologic impairment was the major long-term morbidity. The data show that outcome following blunt vascular trauma of the upper extremity is governed by the associated injuries.

Adolescent↗
PubMed1993

Ultrasonic characterization of the saphenous vein.

The most frequently used conduit for infrainguinal or coronary artery bypass is the saphenous vein, and this report describes the ultrasonic evaluation of anatomic variations in over 1400 limbs. The thigh portion of the greater saphenous vein consisted of a single venous conduit in 67% of the limbs, a complete double system in 8%, a branching double system in 18% and a closed loop double system in 7%. In 92% of the cases, the vein was in medial position, with the remaining 8% positioned laterally. In the calf, a single vein was observed in 65% of the limbs with the remainder demonstrating a double venous system. The vein was positioned anteriorly in 85% of the limbs. The remaining 15% were positioned posteriorly, with 7% of these being a single dominant vein. Proper knowledge of saphenous vein anatomy is vital to the surgeon preparing to use this vein as a bypass conduit and can aid in its preoperative assessment.

Arteriosclerosis↗
PubMed1993

Treatment of the diabetic foot from a vascular surgeon's viewpoint.

Diabetic foot lesions are caused by neurologic, orthopaedic, immunologic, and vascular derangements. Whereas some lesions may be initially caused by trauma and others directly caused by vascular disease, improvement of arterial perfusion often plays an important role in the successful salvage of these limbs. Fortunately, in the last several years, there has been a major improvement in the identification and treatment of those patients in whom correction of arterial occlusive disease is necessary for healing.

Angiography↗