Towards online surface water quality monitoring technology: A review

The exponential growth of human population and anthropogenic activities have led to the increase of global surface water contamination especially in river, lakes and ocean. Safe and clean surface water sources are crucial to human health and well-being, aquatic ecosystem, environment and economy. Thus, water monitoring is vital to ensure minimal and controllable contamination in the water sources. The conventional surface water monitoring method involves collecting samples on site and then testing them in the laboratory, which is time-consuming and not able to provide real-time water quality data. In addition, it involves many manpower and resources, costly and lack of integration. These make surface water quality monitoring more challenging. The incorporation of Internet of Things (IoT) and smart technology has contributed to the improvement of monitoring system. There are different approaches in the development and implementation of online surface water quality monitoring system to provide real-time data collection with lower operating cost. This paper reviews the sensors and system developed for the online surface water quality monitoring system in the previous studies. The calibration and validation of the sensors, and challenges in the design and development of online surface water quality monitoring system are also discussed.

SARS-CoV-2 associated pathogenesis, immune dysfunction and involvement of host factors: a comprehensive review

Infectious diseases, especially viral infections, have emerged as a major concern for public health in recent years. Recently emerged COVID-19, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has been declared a pandemic by World Health Organization since March 2020. It was first identified in Wuhan, China, in December 2019 and has since claimed more than a million lives. Complicated symptoms are associated with rising incidence and fatality rates, while many of the vaccine candidates are in the final stages of clinical trials. This review encompasses a summary of existing literature on COVID-19, including the basics of the disease such as the causative agent's genome characterization, modes of transmission of the virus, pathogenesis, and clinical presentations like associated immune responses, neurological manifestations, the variety of host genetic factors influencing the disease and the vulnerability of different groups being affected by COVID-19.

Roles of primary care physicians in managing bipolar disorders in adults

Management of bipolar disorder (BD) is challenging due to its multiple and complex facets of presentations as well as various levels of interventions. There is also limitation of treatment accessibility especially at the primary care level. Local evidence-based clinical practice guidelines address the importance of integrated care of BD at various levels. Primary care physicians hold pertinent role in maintaining remission and preventing relapse by providing systematic monitoring of people with BD. Pharmacological treatment in particular mood stabilisers remain the most effective management with psychosocial interventions as adjunct. This paper highlights the role of primary care physicians in the management of BD.

Interstudy reproducibility of the second generation, Fourier domain optical coherence tomography in patients with coronary artery disease and comparison with intravascular ultrasound: a study applying automated contour detection

Recently, Fourier domain OCT (FD-OCT) has been introduced for clinical use. This approach allows in vivo, high resolution (15 micron) imaging with very fast data acquisition, however, it requires brief flushing of the lumen during imaging. The reproducibility of such fast data acquisition under intracoronary flush application is poorly understood. To assess the inter-study variability of FD-OCT and to compare lumen morphometry to the established invasive imaging method, IVUS. 18 consecutive patients with coronary artery disease scheduled for PCI were included. In each target vessel a FD-OCT pullback (MGH system, light source 1,310 nm, 105 fps, pullback speed 20 mm/s) was acquired during brief (3 s) injection of X-ray contrast (flow 3 ml/s) through the guiding catheter. A second pullback was repeated under the same conditions after re-introduction of the FD OCT catheter into the coronary artery. IVUS and OCT imaging was performed in random order. FD-OCT and IVUS pullback data were analyzed using a recently developed software employing semi automated lumen contour and stent strut detection algorithms. Corresponding ROI were matched based on anatomical landmarks such as side branches and/or stent edges. Inter-study variability is presented as the absolute difference between the two pullbacks. FD-OCT showed remarkably good reproducibility. Inter-study variability in native vessels (cohort A) was very low for mean and minimal luminal area (0.10 ± 0.38, 0.19 ± 0.57 mm², respectively). Likewise inter-study variability was very low in stented coronary segments (cohort B) for mean lumen, mean stent, minimal luminal and minimal stent area (0.06 ± 0.08, 0.07 ± 0.10, 0.04 ± 0.09, 0.04 ± 0.10 mm², respectively). Comparison to IVUS morphometry revealed no significant differences. The differences between both imaging methods, OCT and IVUS, were very low for mean lumen, mean stent, minimal luminal and minimal stent area (0.10 ± 0.45, 0.10 ± 0.36, 0.26 ± 0.54, 0.05 ± 0.47 mm², respectively). FD-OCT shows excellent reproducibility and very low inter-study variability in both, native and stented coronary segments. No significant differences in quantitative lumen morphometry were observed between FD-OCT and IVUS. Evaluating these results suggest that FD-OCT is a reliable imaging tool to apply in longitudinal coronary artery disease studies.

In-stent restenosis after carotid angioplasty-stenting: incidence and management

PURPOSE

Carotid angioplasty-stenting (CAS) has been advocated as an alternative to carotid endarterectomy (CEA) in patients with restenotic lesions after prior CEA, primary stenoses with significant medical comorbidities, and radiation-induced stenoses. The incidence of restenosis after CAS and its management remains ill defined. We evaluated the incidence and management of in-stent restenosis after CAS.

METHODS

Patients with asymptomatic (61%) and symptomatic (39%) carotid stenosis of > or = 80% underwent CAS between September 1996 and May 2000; there were 50 procedures and 46 patients (26 men and 20 women). All patients were followed up clinically and underwent duplex ultrasonography (DU) at 3- to 6-month intervals. In-stent restenoses > or = 80% detected with DU were further evaluated by means of angiography for confirmation of the severity of stenosis.

RESULTS

No periprocedural or late strokes occurred in the 50 CAS procedures during the 30-day follow-up period. One death (2.2%) that resulted from myocardial infarction was observed 10 days after discharge following CAS. During a mean follow-up period of 18 +/- 10 months (range, 1-44 months), in-stent restenosis was observed after four (8%) of the 50 CAS procedures. Angiography confirmed these high-grade (> or = 80%) in-stent restenoses, which were successfully treated with balloon angioplasty (3) or angioplasty and restenting (1). No periprocedural complications occurred, and these patients remained asymptomatic and without recurrent restenosis over a mean follow-up time of 10 +/- 6 months.

CONCLUSIONS

We recommend CAS for post-CEA restenosis, primary stenoses in patients with high-risk medical comorbidities, and radiation-induced stenoses. In-stent restenoses occurred after 8% of CAS procedures and were managed without complications with repeat angioplasty or repeat angioplasty and restenting.

Mandibular subluxation for distal internal carotid exposure: technical considerations

PURPOSE

Carotid endarterectomy (CEA) has become one of the most commonly performed vascular procedures, because of the beneficial outcome it has when compared with medical therapy alone and because of the anatomic accessibility of the artery. In cases of distal carotid occlusive disease, high cervical carotid bifurcation, and some reoperative cases, access to the distal internal carotid artery may limit surgical exposure and increase the incidence of cranial nerve palsies. Mandibular subluxation (MS) is recommended to provide additional space in a critically small operative field. We report our experience to determine and illustrate a preferred method of MS.

METHODS

Techniques for MS were selected based on the presence or absence of adequate dental stability and periodontal disease. All patients received general anesthesia with nasotracheal intubation before subluxation. Illustrations are provided to emphasize technical considerations in performing MS in 10 patients (nine men and one woman) who required MS as an adjunct to CEA (less than 1% of primary CEAs). Patients were symptomatic (n = 7) or asymptomatic (n = 3) and had high-grade stenoses demonstrated by means of preoperative arteriography.

RESULTS

Subluxation was performed and stabilization was maintained by means of: Ivy loop/circumdental wiring of mandibular and maxillary bicuspids/cuspids (n = 7); Steinmann pins with wiring (n = 1); mandibular/maxillary arch bar wiring (n = 1); and superior circumdental to circummandibular wires (n = 1). MS was not associated with mandibular dislocation in any patient. No postoperative cranial nerve palsies were observed. Three patients experienced transient temporomandibular joint discomfort, which improved spontaneously within 2 weeks.

CONCLUSION

Surgical exposure of the distal internal carotid artery is enhanced with MS and nasotracheal intubation. We recommend Ivy loop/circumdental wiring as the preferred method for MS. Alternative methods are used when poor dental health is observed.

Patency and limb salvage for polytetrafluoroethylene bypasses with vein interposition cuffs

Polytetrafluoroethelene (PTFE) is often utilized in patients with limb-threatening ischemia requiring infrainguinal revascularization in the absence of autologous saphenous vein. To increase long-term patency of PTFE grafts, vein interposition cuffs have been recommended as adjunctive procedures. The purpose of this study was to assess the efficacy of vein interposition cuffs on the long-term patency and limb salvage of patients requiring prosthetic bypass grafts for limb-threatening ischemia. Prosthetic bypass grafts with vein interposition cuffs (PTFE/VC) were performed on 56 limbs in 55 patients (32 men, 23 women; mean age of 67 years) from October 1993 to January 1998. Grafts were prospectively evaluated every 3 months for the first 12 months and biannually thereafter with duplex ultrasonography. PTFE/VC and PTFE bypasses at the popliteal level appear to have comparable patencies. However, PTFE/VC appear to offer an improved patency and limb salvage for infrapopliteal bypasses in patients with critical limb ischemia. When infrapopliteal revascularization is required in the absence of autologous saphenous vein, we recommend the use of PTFE with vein interposition cuffs.

Hemodialysis access: influence of the human immunodeficiency virus on patency and infection rates

PURPOSE

The complication rate for patients who are dialysis dependent and infected with the human immunodeficiency virus (HIV) and the role of viral indicators (CD4 counts) as predictors of these complications are poorly characterized. To determine the influence of HIV status and viral activity on graft patency and infection rates, we retrospectively reviewed our results.

METHODS

Between June 1993 and March 1997, the charts of 104 patients (HIV+, n = 42; HIV-, n = 62) who required 112 hemodialysis access grafts were reviewed. Of the 112 procedures, 55 (48%) were autologous arteriovenous fistulae (AVF) procedures (HIV+, n = 23; HIV-, n = 32) and 57 (52%) were prosthetic expanded polytetrafluoroethylene grafting procedures (HIV+, n = 27; HIV-, n = 30). Transcutaneous catheter procedures were excluded from the study. The autologous AVF procedures consisted of direct and transposed AVFs. Patency rates were determined by means of life-table analysis. Infection rates and CD4 counts were compared with the chi2 test and the Fisher exact test. Significance was accepted at a P value of.05 or less.

RESULTS

The cumulative 12-month and 24-month patency rates for prosthetic grafts in patients who were HIV+ were 49% and 21%, respectively, versus 77% and 45% for patients who were HIV-. The differences in the prosthetic graft patency rates between these two groups were significant (P </=.05). The cumulative 12-month and 24-month patency rates for autologous AVF procedures did not differ significantly. The AVF procedure patency rates were 72% and 51%, respectively, in patients who were HIV+ versus 54% and 50% for patients who were HIV-. The prosthetic graft infection rate for patients who were HIV+ and HIV- were 30% and 7%, respectively ( P =.04). However, the infection rates in autologous AVF procedures did not differ between the groups (9% vs 0%; P>.05). The mean CD4+ cell counts were 174: CD4+ counts that were less than 200 did not correlate with or predict the development of infection (P >.05).

CONCLUSION

Our data showed that prosthetic graft infection rates were increased and patency rates were decreased in patients who were HIV+ as compared with patients who were HIV- and HIV+ with autologous AVFs. There were no differences in patency rates or infection rates in patients who had undergone autologous access procedures. Long-term graft patency rates were not affected by HIV status, and CD4+ lymphocyte counts were not predictive of infection development. Because the prosthetic graft infection rates exceeded those rates of autologous access procedures, we recommend the vigorous use of autologous AVFs in all patients who are HIV+, regardless of CD4+ count.

Carotid restenosis: operative and endovascular management

PURPOSE

Surgical management of carotid restenosis (CR) after carotid endarterectomy (CEA) has been associated with a higher perioperative complication rate than that of primary CEA. We recently used carotid angioplasty-stenting (CAS) as an alternative to operative management in patients who had undergone CEA within three years, and we retrospectively compared these results with those of operative management of CR and the overall results of CEA.

METHODS

CEA was performed on 1065 adult patients (58% symptomatic, 42% asymptomatic), 62% of whom were men (n = 660) and 38% of whom were women (n = 405), from 1989 to 1997. Before our initiation of a program of CAS, 16 operative procedures (1.9% of CEAs) were performed for CR in 14 adult patients (7 women and 7 men). During the last 20 months, CAS was used in the management of 17 CRs (16 patients; 9 women and 7 men).

RESULTS

The 30-day stroke morbidity-death rate for all CEAs (n = 1065) was 1.4%; 11 strokes (1. 0%) occurred (4 major strokes with disability and 7 strokes with minor or no disability), and 4 deaths (0.4%) occurred (2 deaths caused by myocardial infarction, 1 caused by intracranial hemorrhage, and 1 caused by stroke). Operative management of CR (n = 16) included patch angioplasty in 12 cases (autologous vein patches in 10 cases and synthetic patches in 2 cases), whereas interposition grafting was used in 4 cases (saphenous vein in 3 instances and synthetic [polytetrafluoroethylene] in one case). No strokes or deaths were observed. One recurrent laryngeal nerve palsy occurred (6.2%). Among the 16 patients undergoing 17 CAS procedures, the technical procedures were accomplished in all patients. No strokes or deaths occurred. No recurrent restenoses (50% or greater) have been identified within or adjacent to the CAS procedures.

CONCLUSION

CR caused by myointimal hyperplasia can be managed by operative techniques or CAS with comparable periprocedural complications. Although long-term follow-up will be required to determine the incidence of recurrent restenosis, CAS may become the preferred procedure in these cases. A randomized clinical trial ultimately will be necessary to determine the role of CAS, as compared with that of operative management.

Patency of infrainguinal polytetrafluoroethylene bypass grafts with distal interposition vein cuffs

Polytetrafluoroethylene (PTFE) prosthetic bypasses in the lower extremity have poor patency rates, particularly in limb salvage cases. Patency and limb salvage rates of PTFE bypasses supplemented by distal interposition vein cuffs were assessed in patients requiring revascularization for critical limb ischemia, in the absence of a suitable autologous saphenous vein. Between October 1993 and April 1996, 163 patients underwent 185 infrainguinal bypasses. Forty-three limbs in 42 patients (12 women, 30 men; mean age 67 years) did not have a suitable autologous saphenous vein (24%) and had femoropopliteal (20) and infrapopliteal (23) bypasses performed. Patients were examined prospectively at 3-month intervals during the first year and at 6-month intervals thereafter to determine graft patency and limb salvage. Postoperative anticoagulation with warfarin was used in 26 patients. Indications for operation included limb salvage in 41 extremities (21 rest pain/ulceration or gangrene, 20 rest pain alone), and disabling claudication in two. Patients were followed clinically for 2-30 months (mean 10 months). Cumulative 2-year life-table patencies for all grafts, femoropopliteal and infrapopliteal bypasses were 64%, 75% and 62%, respectively. Previous primary patencies at the authors' institution for PTFE bypasses without vein cuffs were 35%, 46% and 12% for the same categories. Cumulative life-table limb salvage for all PTFE/vein cuff bypasses in the present series was 76% compared with 37% in previous PTFE bypasses without vein cuffs. Adjunctive use of distal interposition vein cuffs improves prosthetic graft patency, while producing satisfactory limb salvage. Postoperative anticoagulation did not influence graft patency. PTFE/vein cuff for lower-extremity revascularization shows good 2-year patency and is an acceptable alternate conduit in patients with critical limb ischemia when autologous saphenous vein is absent.

A strategy for increasing use of autogenous hemodialysis access procedures: impact of preoperative noninvasive evaluation

PURPOSE

We studied the efficacy of preoperative noninvasive assessment of the upper extremity to identify arteries and veins suitable for hemodialysis access to increase our use of autogenous fistulas (AF).

METHODS

From Sep. 1, 1994, to Apr. 1, 1997, 172 patients who required chronic hemodialysis underwent segmental upper extremity Doppler pressures and duplex ultrasound with mapping of arteries and veins. The following criteria were necessary for satisfactory arterial inflow: absence of a pressure gradient between arms, patent palmar arch, and arterial lumen diameter 2.0 mm or more. The criteria necessary for satisfactory venous outflow were venous luminal diameter greater than or equal to 2.5 mm for AF and greater than or equal to 4.0 mm for synthetic bridging grafts (BG) and continuity with distal superficial veins in the arm. Intraoperative and duplex ultrasound measurements were compared. Contemporary experience was compared with the 2-year period (1992 to 1994) before implementation of the protocol.

RESULTS

During the period from Sep. 1, 1994, to Apr. 1, 1997, 108 patients (63%) had AF, 52 (30%) had prosthetic BG, and 12 (7%) had permanent catheters (PC) placed. Early failure was seen in 8.3% of AFs. Primary cumulative patency rates were 83% for AF and 74% for BG at 1 year (p < 0.05), with a mean clinical follow-up of 15.2 months. No postoperative infections were observed with AF, whereas six infections (12%) were observed with BG and two (17%) with PC insertion. During the period from June 1, 1992, to Aug. 31, 1994, 183 procedures were performed with a distribution of 14% AF, 62% BG, and 24% PC. In this earlier period the AF early failure rate was 36%, and the patency rates were 48%, 63%, and 48% for AF, BG, and PC, respectively (mean follow-up, 13.8 months).

CONCLUSION

A protocol of noninvasive assessment increased use of AFs. The cumulative patency rate of AFs was improved, and early failure rates were reduced when compared with the preceding institutional experience. Routine noninvasive assessment is recommended to document adequacy of arterial inflow and delineate venous outflow to maximize opportunities for AF.

Vein transposition in the forearm for autogenous hemodialysis access

PURPOSE

We describe a technique of superficial venous transposition in the forearm used for the formation of an arteriovenous fistula for hemodialysis access. These modifications of the single-incision radiocephalic fistula are designed to increase options for arteriovenous fistulas by using veins and arteries that are suitable for use but are not in immediate proximity.

METHODS

Arteries and veins suitable for a primary arteriovenous fistula were identified and mapped using duplex ultrasound in 89 patients. Separate incisions were used in the majority of cases, and the selected forearm vein was mobilized, angiodilated, and transposed into a subcutaneous tunnel on the volar aspect of the forearm. Before initiation of hemodialysis, duplex ultrasound scanning was performed, and the location that was most suitable for cannulation was identified. Repeat scans were performed at 3-month intervals for analysis of patency.

RESULTS

Superficial venous transpositions were performed using a single incision in 13 instances in which the vein was in immediate proximity to the radial artery (type A). Dorsal-to-volar forearm transposition (type B) was performed in 30 veins with anastomoses to the radial (n = 26), ulnar (n = 2), or brachial (n = 2) arteries. Volar-to-volar forearm transposition (type C) was performed in the remaining 46 veins, with anastomoses to the radial (n = 42), ulnar (n = 2), or brachial arteries (n = 2). Successful hemodialysis was accomplished in 81 of 89 patients (91%). The primary cumulative patency rate was 84% at 1 year and 69% at 2 years. The mean duration of follow-up was 14.3 months.

CONCLUSIONS

The use of superficial venous transposition for the formation of autogenous hemoaccess was associated with ease of cannulation by dialysis personnel, high maturation rates, reduced early failure rates, and enhanced patency rates. We recommended the use of these technical modifications to increase the use of autogenous fistulas in the forearm.

Carotid arterial trauma: assessment with the Glasgow Coma Scale (GCS) as a guide to surgical management

Management of carotid arterial injuries associated with focal neurological deficit or altered state of consciousness (SCON) remains unresolved. Experience with these injuries in one particular hospital was reviewed and the Glasgow Coma Scale (GCS) utilized to assist with clinical stratification of these patients. A literature review was also conducted to better define indications for repair or ligation of carotid injuries. From 1978 to 1990, 34 patients with carotid arterial injuries were reviewed with reference to the GCS, focal deficit, hypotension, anatomic site and mechanism of injury. The literature from 1952 to 1993 was surveyed for carotid artery injuries (1316 patients). Outcome of treatment with or without repair was compared with pre-operative neurologic status. Thirty-four patients with injuries of the common (24) or internal (10) carotid arteries were managed with repair (68%), ligation (24%) or observation (9%). The SCON was normal in 18 patients; 16 patients (88%) underwent repair and all remained normal. All patients with GCS 9-14 regained a normal SCON after surgical repair, while 10 patients with GCS < 8 had repair (5), ligation (3), and non-operative management (2); five returned to normal, four died and one remained comatose. However, outcomes correlated poorly with management. Of 1316 patients cited in the surgical literature, patients with no deficit and patients with pre-operative deficits did significantly better after repair as compared with ligation (P<0.001). In comatose patients, management did not affect outcome. It is concluded that carotid arterial injuries should be repaired in patients with normal neurologic evaluation, focal pre-operative neurologic deficits and in patients with GCS > 9. Comatose patients with GCS < 8 do poorly regardless of management. The GCS provides an objective for stratification of patients with altered SCON who benefit from repair of carotid arterial injuries.

Outcome of complex venous reconstructions in patients with trauma

PURPOSE

The role of complex venous reconstructions (CVRs) in patients with major trauma remains a controversial topic. This study evaluates the patency and clinical outcome of CVRs in a major urban trauma center.

METHODS

Between 1979 and 1994 the records of 92 patients with 100 injuries to the iliac, femoral, and popliteal venous system were reviewed. The incidence of edema, pulmonary embolism, and limb loss was documented in 75 men and 17 women (mean age of 27 years, range 14 to 59 years). The 30-day patencies were assessed in all patients with either impedance plethysmography (n = 16), venography (n = 40), or duplex scan (n = 36). Long-term patencies were assessed in 14 patients monitored for 0.5 to 9 years (mean 3.2 years).

RESULTS

Mechanisms of injury consisted of 58 gunshot wounds, 23 stab wounds, 6 shotgun wounds, and 5 blunt injuries. There were 112 associated injuries, 41 of which were concomitant arterial injuries. Forty-five of the 100 venous injuries were repaired with CVRs and included 6 (13%) spiral vein grafts, 8 (18%) panel vein grafts, 8 (18%) reversed saphenous vein interposition grafts, 8 (18%) end-to-end repairs, and 15 (33%) vein patch repairs. Thirty-day patency rates for these repairs were 50%, 50%, 75%, 88%, and 87%, respectively, and an overall patency rate of 73% was observed. The remaining 55 injuries were treated with ligation (n = 27) or lateral venorrhaphy (n = 28). The cumulative 30-day patency rate for all venous repairs was 81% (59 of 73). Fourteen patients, nine of whom had CVRs, were available for long-term follow-up. In this group CVRs demonstrated a 100% patency. One patient with a spiral vein graft repair of the common femoral vein had severe reflux causing intermittent edema and mild lipodermatosclerosis. No pulmonary emboli, limb loss, or deaths were identified in patients undergoing CVRs.

CONCLUSION

Patients with CVRs had a 30-day patency rate of 73%. Of this group panel and spiral vein grafts were less successful, exhibiting only a 50% 30-day patency rate, whereas end-to-end and vein patch repairs were successful in 88% and 87% of cases, respectively. Our overall evaluation suggests that use of CVRs results in successful venous repair; however, the postoperative patency of interposition panel and spiral grafts suggests selective use of these techniques.

A program of operative angioplasty: endovascular intervention and the vascular surgeon

PURPOSE

Vascular surgeons are ideally suited to select and perform endovascular interventions either as primary therapy or as an adjunct to bypass surgery. Attaining proficiency in endovascular techniques is an important goal in the training of vascular surgeons. We report our initial experience with a program of endovascular intervention performed in the operating room by vascular surgeons.

METHODS

During the previous three years, we performed 109 angioplasty procedures, 60 aortoiliac (55%), 32 femoropopliteal (29%), and 17 popliteal/tibial (16%), using guidewires and angioplasty balloons directed by intraoperative digital subtraction C-arm arteriography with road-mapping capabilities. Indications for angioplasty included disabling claudication in 59 patients (54%), rest pain in 18 (17%), and tissue loss in 32 (29%). Angioplasty was accompanied by stent placement in 39 of 60 aortoiliac procedures (65%) and in two of 32 femoral procedures (6%). In 16 cases (15%), the endovascular procedure was performed in conjunction with a bypass procedure. In selected cases (15, 14%), duplex scanning was the sole diagnostic method used before surgery to identify the lesion, eliminating the need for preoperative arteriographic scans. Segmental pressure measurements, duplex ultrasound scans, and treadmill exercise testing as indicated were performed before and after surgery. The efficacy of the endovascular intervention was assessed at 3-month intervals during the first year and at 6-month intervals thereafter.

RESULTS

A successful results was defined using criteria recommended by the Ad Hoc Subcommittee on Reporting Standards for Endovascular Procedures from the Society for Vascular Surgery/International Society for Cardiovascular Surgery. This included the combination of symptomatic improvement, obtaining an anatomically successful result with < 30% residual lumen stenosis, and elimination of the translesion gradient with an improvement in high thigh-brachial index or ankle-brachial index greater than 0.15. Initial success was achieved in 55 of 60 aortoiliac (92%), 28 of 32 femoropopliteal (88%), and 16 of 17 popliteal/tibial (94%) angioplasty procedures. Clinical follow-up has been achieved in all cases, with continued clinical success rates of 80%, 75%, and 82% for aortoiliac, femoropopliteal, and popliteal/tibial angioplasty procedures, respectively, with a mean follow-up of 15.7 months.

CONCLUSION

These results confirm the value of a program in which C-arm technology was used by vascular surgeons in the performance of angioplasty and stenting procedures in the operating room. This experience in therapeutic endovascular intervention will facilitate the credentialing process for future vascular surgeons.

The significance of calf muscle pump function in venous ulceration

PURPOSE

Patients with clinically evident chronic venous insufficiency were evaluated to relate the degree of insufficiency and calf muscle pump dysfunction to venous ulceration.

METHODS

Sixty-nine limbs in 55 patients with chronic venous insufficiency by Society for Vascular Surgery/International Society for Cardiovascular Surgery Classification were compared in three groups: classes 1 and 2 with no history of ulceration (19 limbs); class 3 with healed ulceration (20 limbs); and class 3 with active ulcers (30 limbs). Air plethysmography measurements of outflow fraction, venous volume, venous filling time, venous filling index, ejection fraction, ejection volume, residual volume fraction, and residual volume were made. In 62 of the 69 limbs, color-flow duplex ultrasonography was used to determine the pattern of reflux.

RESULTS

The outflow fraction was normal in 84%, 75%, and 77% of nonulcerated, healed, and ulcerated limbs. The venous filling index was abnormal in most limbs (nonulcerated 95%, healed 90%, ulcerated 98%) but not significantly different among groups. Differences in calf muscle pump function were significant. Ulcerated limbs had significantly poorer ejection fractions (p = 0.0002) and greater residual volume fractions (p = 0.0006) than nonulcerated or healed limbs. By ultrasonography, deep and superficial vein incompetence was present in most limbs and was not statistically different among groups. Although venous insufficiency was not measurably different among groups, limbs with active venous ulcers had significantly poorer calf muscle pump function than those with healed ulcers or with no history of ulceration.

CONCLUSION

Venous insufficiency is necessary but not sufficient to cause ulceration, and a deficiency of the calf muscle pump is significant to the severity of venous ulceration.

Carotid endarterectomy for asymptomatic carotid stenosis: a ten-year experience with 120 procedures in a fellowship training program

Performance of carotid endarterectomy for asymptomatic carotid stenosis has been restricted during recent years because of concern of reported complications in as high as 10-15% of patients, as well as limited long-term data on stroke protection. During the last 10 years, we have studied immediate and long-term results of carotid endarterectomy for asymptomatic disease in 120 patients. Operations were performed by a clinical vascular fellow with a staff surgeon in attendance in 113 (94%) cases with the remainder performed by the staff surgeon. Patients' mean age was 66 years; 82% were men. Risk factors included hypertension (56%), smoking (52%), coronary artery disease (32%), diabetes (24%), and hypercholesterolemia (6%). Arteriographic severity of stenoses was 80-99% in 74%, 60-79% in 22%, and 40-59% in 4% of cases. Postoperative complications included two transient neurological events (1.7%). No permanent strokes or deaths occurred. Using the life table method, cumulative stroke rate was 4.5% for ipsilateral events and 7.3% for contralateral events, confirming the high degree of stroke protection afforded by carotid endarterectomy in this population. Since these results were accomplished in a fellowship training program, we regard adequacy of this experience as the most influential factor in accomplishing this record. Surgeons who are unable to achieve comparable results should consider abandonment of the procedure or an extended period of additional training.

Intravascular ultrasonography: validation studies and preliminary intraoperative observations

Intravascular ultrasonography is emerging as an important imaging modality to assess the presence, distribution, and extent of atherosclerotic vascular disease. To determine the accuracy and clinical utility of intravascular ultrasonography, a flexible catheter-based system was used to generate two-dimensional, cross-sectional vascular images. In 23 arteries of 11 sheep 206 in vivo images demonstrated an echo-free lumen surrounded by three distinct concentric acoustic transitions corresponding to intima, media, and adventitia. Ultrasound measurements of lumen diameter and area correlated significantly with those of corresponding arteriographic measurements obtained by use of digital calipers (r = 0.91, r = 0.86). To evaluate clinical feasibility, intraoperative images (n = 160) were obtained in 10 patients undergoing vascular bypass or hemodialysis access procedures. The images depicted luminal configuration and arterial wall morphologic characteristics. Measurements of lumen diameter and lumen area correlated closely with corresponding intraoperative arteriography (r = 0.81, r = 0.79). The ultrasound images demonstrated arterial stenoses, intimal hyperplasia, intraluminal thrombus, polytetrafluoroethylene graft material, and anastomotic sites. We conclude that flexible catheter-based ultrasonography produces images that accurately demonstrate arterial wall architecture, lumen diameter, and area. Intraoperative application can produce images that provide unique information thus expanding the clinical potential of ultrasonography as a guidance system for vascular procedures.

Reduced dependency on arteriography for penetrating extremity trauma: influence of wound location and noninvasive vascular studies

Indications for arteriography in penetrating extremity trauma remain controversial. We reviewed our clinical experience in 454 patients (514 extremities) with penetrating trauma admitted during a prior 3 1/2-year period. Injuries were caused by stab wounds in 60 (11.7%) extremities and by gunshot wounds in 454 (88.3%) extremities. Thirty-three of the 60 stab wounds (55%) required urgent exploration, and 27 underwent arteriography. No arteriograms were positive for unsuspected arterial injury in this group. Forty-two of 454 gunshot wounds (9.3%) underwent mandatory exploration; arteriograms were performed on 412 extremities. Forty-four arteriograms (10.7%) demonstrated evidence of unsuspected arterial injuries. During the last year, randomly selected extremities (n = 23) have been studied with B-mode ultrasonography and segmental Doppler pressure measurements. Using the subsequent arteriography as the "gold" standard, sensitivity was 83% and specificity was 100%. Gunshot wounds were categorized according to location and positive arteriograms. Injuries to the lateral thigh and arm resulted in no positive arteriograms, while positive studies were observed in 11% of medial and posterior arm, 14% of antecubital fossa, 25% of forearm, 7.5% of medial and posterior thigh, 8% of popliteal fossa, and 26% of calf injuries. We recommend arteriography for gunshot injuries to identified high-risk areas, while clinical evaluation alone is accurate in all stab wounds to the extremities and gunshot wounds to the lateral thigh and outer arm. Preliminary data suggest expanded use of B-mode ultrasonography may further reduce our dependency on arteriography in these cases.

Penetrating extremity trauma: identification of patients at high-risk requiring arteriography

Indications for arteriography in patients with penetrating trauma to the extremities remain controversial. Some clinicians have recommended universal use of arteriography, whereas others prefer to rely on physical findings alone. To better define our indications for contrast studies, we reviewed clinical data on 306 patients (349 extremities) with penetrating trauma who were admitted during a prior 2-year period (1985 to 1987). Injuries were caused by stab wounds in 50 (14.3%) extremities and by gunshot wounds in 299 (85.7%) extremities. Twenty-seven of the 50 stab wounds (54%) required urgent exploration based on physical findings, whereas 23 underwent arteriography. None of these studies showed unsuspected arterial injury. Twenty-nine of 299 gunshot wounds (9.7%) underwent mandatory exploration, and arteriograms were performed on 270 extremities; findings in 30 studies (11.1%) were positive for unsuspected arterial injuries. Gunshot wounds were categorized according to location and number of arteriograms with positive results. Arteriograms of lateral thigh and upper arm injuries resulted in no positive outcomes. Positive study results were recorded in 22.9% of calf injuries, 20% of forearm and antecubital injuries, 9.5% of popliteal fossa injuries, 9.0% of medial and posterior thigh injuries, and 8.3% of medial and posterior upper arm injuries. We recommend arteriography for penetrating injuries to these high-risk areas. However, clinical evaluation alone is accurate for identification of arterial trauma with lateral thigh or upper arm wounds and stab wounds to the extremities.

Diagnosis of acute deep venous thrombosis

This article outlines the application of continuous-wave Doppler, plethysmographic techniques, and B-mode ultrasonography to the diagnosis of suspected deep venous thrombosis in ambulatory patients. Methodology is evaluated, and the diagnostic accuracy and application of these studies are reviewed. The authors' current algorithm for the application of these noninvasive studies also is presented.

Studies on the allergenicity of the developing spores of Pteris vittata L

Ninety patients were investigated with intradermal testing of developing stages of Pteris vittata L., whole spores, and their fractions. Allergenic principles were found to be present in both protoplasm and spore wall of the fertile tissue.

Intestinal obstruction: still a lethal clinical entity

A retrospective analysis of 70 consecutive patients with a clinical diagnosis of intestinal obstruction from January 1983 to September 1985 was reviewed. Mean age was 62 years. Etiological factors included adhesions 50 percent, malignancy 24 percent, volvulus 12 percent, diverticulitis 7 percent, hernias 4 percent, and radiation enteritis, mesenteric infarction, and perforation of the cecum in the remaining 3 percent. Complications included wound infection 9 percent (n = 6), intra-abdominal sepsis 7 percent (n = 5), and recurrent small bowel obstruction 4 percent (n = 3). Overall mortality was 24 percent (n = 7).Results of the univariant analysis showed no association between the clinical signs of intestinal obstruction, that is, fever, tachycardia, leukocytosis, and local tenderness, and gangrenous bowel. A multiple regression analysis showed, however, that only 14 percent of the variance was able to predict the gangrenous bowel based on clinical signs. In conclusion, the classical signs of intestinal obstruction are poor indicators for compromised bowel, and early surgical intervention will reduce the incidence of ischemic bowel and mortality.

Carotid restenosis: long-term noninvasive follow-up after carotid endarterectomy

Recurrent stenosis has not been a primary consideration in the selection of patients for carotid endarterectomy. We have studied the incidence of postoperative restenosis retrospectively in 265 patients following 310 carotid endarterectomies. Two hundred fourteen patients (248 endarterectomies) were examined at 6-12 month intervals using ocular pneumoplethysmography, spectral analysis, and B-mode imaging. The absolute incidence of recurrent carotid disease was 28% (69 of 248), with a 13% (33 of 248) incidence of hemodynamically significant restenosis and a 15% (36 of 248) incidence of hemodynamically insignificant disease. Life table analysis of the data projected a 32% incidence of hemodynamically significant restenosis after 7 years and a 40% incidence of hemodynamically insignificant recurrence. These data demonstrate a progressively increasing rate of restenosis. The incidence of ipsilateral neurologic events was 8% (24 of 310); 12 occurred in association with noninvasively evident recurrent disease (12 of 69, 17%), whereas 11 occurred in noninvasively determined normal arteries (11 of 179, 6%). Noninvasive follow-up was not available in 1 patient. Of the 12 events associated with recurrent disease, 5 occurred in association with hemodynamically significant restenosis (5 of 33, 15%), whereas 7 occurred in association with hemodynamically insignificant disease (7 of 36, 19%). Carotid endarterectomy is a durable operative procedure with 92% (286 of 310) of arteries remaining asymptomatic over the period of clinical follow-up. However, absolute and life table projections of the incidence of asymptomatic restenosis are high, and this factor should be considered in the selection of patients for carotid endarterectomy, particularly in the absence of lateralizing symptoms.

Digital subtraction angiography versus noninvasive testing in the vascular assessment of the ischemic foot

This report discusses the role of digital subtraction angiography as well as noninvasive vascular testing in the evaluation of the ischemic foot. A case history is described presenting the diagnostic modalities and surgical management of an insulin-dependent diabetic man with gangrene.

The value of laser Doppler velocimetry and transcutaneous oxygen tension determination in predicting healing of ischemic forefoot ulcerations and amputations in diabetic and nondiabetic patients

The ability to predict successful healing of ulcerations and amputations of the ischemic forefoot continues to be a major clinical challenge, particularly in diabetic patients whose systolic Doppler ankle pressures are often artifactually elevated. We have used the techniques of laser Doppler velocimetry (LD) and transcutaneous oxygen tension monitoring (tcPO2) to quantitatively measure skin blood flow in the distal foot. Fifty-nine limbs were studied (48 patients), of which 37 (63%) were in diabetic and 22 (37%) in nondiabetic patients. All patients were admitted with ischemic ulcerations or gangrenous changes of the forefoot or digit. Twenty transmetatarsal or digital amputations were performed; the remainder of the lesions were débrided and allowed to heal by secondary intention or were covered by a skin graft. Before operation, the systolic pressure (expressed in millimeters of mercury, mean +/- SEM) was measured by Doppler technique at the ankle, and the ankle/arm index calculated (n = 59 limbs). The tcPO2 (also expressed in millimeters of mercury, mean +/- SEM) was measured from the dorsal foot (n = 56). The baseline skin blood flow velocity (SBFV) and pulse wave amplitude (PWA) were measured with the LD (expressed in millivolts, mean +/- SEM) on the plantar aspect of the foot (n = 53 limbs). Criteria for successful healing included a tcPO2 of more than 10 mm Hg, the combination of an LD-SBFV of more than 40 mV and an LD-PWA of more than 4 mV, and an ankle systolic pressure of more than 30 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)

Simultaneous determination of brachial and femoral arterial pressures during reactive hyperemia and papaverine vasodilation

Accurate assessment of aortoiliac occlusive disease often requires direct intraarterial pressure determination. Since these measurements may alter systemic pressure, brachial arterial pressure (BAP) and femoral arterial pressure (FAP) were obtained simultaneously to quantitate these changes. BAP and FAP were measured at rest, and then during vasodilation produced by postischemic reactive hyperemia and intra-arterial injection of papaverine. The gradient between FAP and BAP was used to assess the significance of an aortoiliac stenosis. Sixty-eight observations were performed in 19 limbs. During reactive hyperemia (n = 28), BAP was 142 +/- 7 mm Hg, which was not significantly different from the baseline BAP of 142 +/- 5 mm Hg. However, during thigh tourniquet inflation, BAP increased significantly to 158 +/- 7 mm Hg. Following papaverine injection (N = 21) BAP was 144 +/- 8 mm Hg, which was significantly different from both the baseline BAP (150 +/- 6 mm Hg) and the preinjection BAP (156 +/- 6 mm Hg). Postischemic reactive hyperemia and papaverine vasodilation produced comparable brachial to femoral pressure gradients. Use of baseline BAP is recommended for calculating gradients during reactive hyperemia, since the BAP is significantly elevated during tourniquet occlusion. Simultaneous recording of brachial and femoral pressures is recommended with intra-arterial papaverine injections, since the BAP varies significantly throughout the examination.

The role of contrast arteriography in suspected arterial injuries of the extremities

The records of 215 patients presenting with 218 penetrating or blunt injuries to the extremities from 1977 through 1983 have been reviewed. All patients presenting with pulsatile hemorrhage, expanding hematoma, or absent distal pulses were explored immediately. Patients with injuries in close proximity to a major artery but without classical signs of arterial injury were explored routinely from 1977 through 1980. Thereafter, similar patients were evaluated initially with contrast arteriography and explored only if arteriographic abnormalities suggested arterial injury. Routine exploration of proximity injuries has been compared with selective exploration based on contrast arteriography. Sixty-one patients (group 1) underwent routine exploration for proximity injuries. Vascular injuries were detected in ten (16%) patients, while 51 (84%) of the explorations were negative. Eighty-four patients (group 2) with proximity injuries were studied arteriographically. Ten patients (11.9%) were explored on the basis of abnormal arteriograms, and eight arterial injuries were confirmed. Two (2.4%) of the 84 patients in this group had negative explorations. The use of contrast arteriography enabled the authors to reduce their negative exploration rate from 84 to 2.4 per cent in the management of proximity injuries.

Results of revascularization and amputation in severe lower extremity ischemia: a five-year clinical experience

Aggressive revascularization of the ischemic lower extremity in atherosclerotic occlusive disease by femoropopliteal (FP) and femorotibial (FT) bypass or profundaplasty (P), as indicated, has been advocated by some authors for all patients. Others have recommended primary amputation, particularly for tibial occlusive disease. To clarify this clinical dilemma, we reviewed the results of 547 procedures performed during the last 5 years: revascularization in 375 (69%) instances and below-knee amputation (BKA) in 172 (31%) cases. Bypass procedures were used in 246 cases: FP in 155 (64%) and FT in 91 (37%). Reversed autogenous saphenous vein (ASV) was used preferentially in 125 (51%) cases, whereas polytetrafluoroethylene (PTFE) was used in 121 (49%) cases. P was performed in 129 instances accompanied by inflow procedures in 92 (71%) of these cases. Cumulative limb salvage (LS) exceeded bypass patency in all categories and resulted in 2- and 5-year LS rates of 83% and 81% for FP with the use of ASV and 52% and 35% for PTFE. The LS rate for FT was 53% and 47%, respectively, for ASV and 20% and 15% for PTFE. Rest pain was successfully relieved by P in 99 cases (77%), whereas healing occurred in only 51% of cases with tissue loss. The perioperative mortality rate for revascularization was 3%; 42% of the group died during follow-up, death usually resulting from complications of atherosclerosis. Of the 172 BKAs, primary healing occurred in 80%, but the perioperative mortality rate was 13%. FP and FT bypasses are preferred procedures if ASV is available, whereas use of PTFE should be limited to FP bypasses only. Rest pain is relieved by P but tissue loss should prompt consideration for bypass. BKA should be considered in cases of severe tibial disease only in the absence of a suitable ASV, as the perioperative mortality rate is high and ultimate rehabilitation (64%) is limited.

Use of intermittent pneumatic compression of the calf in femoral venous reconstruction

Application of intermittent compression of the calf is described as an adjunct to maintain patency of femoral venous reconstruction following trauma. Its use in instances of femoral and popliteal venous reconstructions is recommended.

Popliteal and infrapopliteal arterial injuries. Differential management and amputation rates

A 3-year clinical experience is analyzed to define preferred surgical management and amputation rates for popliteal as well as infrapopliteal arterial injuries. Ten patients with popliteal arterial trauma were successfully managed without amputation, however, five of 11 (45%) patients with infrapopliteal arterial trauma required amputation. While essentially all popliteal arterial injuries mandate repair, recommendations for repair or ligation of isolated tibial arterial injuries are based on presence of distal ischemia, the patient's associated injuries, as well as estimated operating time for reconstruction. With injury to two or three infrapopliteal arteries, distal ischemia is usually present and arterial repair indicated, unless there has been severe crush injury, prolonged delay, or extended surgery would jeopardize the patient's life. A management protocol for patients with distal ischemia related to popliteal or infrapopliteal arterial trauma should include prompt surgical intervention, liberal use of fasciotomy, intraoperative arteriography, as well as the selective use of intraluminal shunts.

Revascularization of the profunda femoris artery for limb salvage

The clinical outcome of 88 profundaplasties in 70 patients operated upon during the period 1978 to 1982 was related to indications for operation, status of arterial run-off, influence of a concomitant inflow procedure, and changes in Doppler ankle-brachial index (ABI). Operative procedures were performed for rest pain (49 limbs), ulceration (24 limbs), and gangrene (13 extremities). Primary profundaplasty (PP) was performed in 26 (29%) cases. Sixty-two procedures (71%) were inflow profundaplasties (IP) performed in conjunction with other proximal reconstructions. Overall clinical success was achieved in 67 extremities (76%). When the operation was performed for rest pain, and the arterial run-off was good, success rate was 78 per cent and 79 per cent, respectively, as compared to 51 per cent and 57 per cent for ulceration/gangrene and poor arterial run-off. For PP, satisfactory outcome was noted in 69 per cent as compared to 79 per cent in IP. In the clinically successful profundaplasties, mean preoperative ABI was 0.29 and increased significantly to 0.53 postoperatively (P = 0.04). In the clinical failures, mean preoperative ABI was 0.32, and postoperative ABI was 0.38, which was not statistically significant (P greater than 0.05). Profundaplasty is a reliable operation particularly when the indication is rest pain, and the arterial run-off is good. Poor results can be anticipated when the procedure is performed for tissue loss, or if the arterial run-off is poor. Clinical outcome for the PP and IP groups were comparable.

Ultrasonic imaging and oculoplethysmography in diagnosis of carotid occlusive disease

Pulsed Doppler ultrasonic imaging (UI) of the cervical carotid artery provides flow-dependent anatomic detail of the carotid bifurcation, while oculoplethysmography (Kartchner) (OPG-K) and ocular pneumoplethysmography (Gee) (OPG-G) reflect changes in flow and pressure resulting from hemodynamically significant lesions. We examined 66 patients prospectively with UI, OPG-K, and OPG-G to compare the relative accuracy of these techniques with contrast arteriography. Both UI and OPG-G were significantly more accurate than OPG-K. While the accuracies of UI and OPG-G were not significantly different, their combined use resulted in a significant increase in sensitivity compared with that of Doppler imaging alone. In addition, UI correctly identified 22 (85%) of 26 occlusions of the internal carotid artery. The use of UI and OPG-G together provided accurate anatomic and hemodynamic information useful in the evaluation of carotid occlusive disease.

Femoral venous trauma: techniques for surgical management and early results

During a 4 year period (1979 through 1983), 181 major arterial (69 percent) and 81 venous (31 percent) injuries were treated surgically. Of the venous injuries, 24 (30 percent) involved the femoral veins (9 common femoral, 15 superficial femoral). Management of these femoral venous injuries included lateral venorrhaphy in 10 cases (42 percent), venous patch angioplasty in 5 cases (21 percent), end-to-end anastomosis in 4 cases (17 percent), interposition autogenous saphenous vein grafts in 3 patients (12 percent), and ligation in 2 cases (8 percent). One case that included common femoral venous ligation and one that included a failed interposition saphenous vein graft in the superficial femoral vein subsequently were managed with in situ saphenous vein bypass. For one interposition saphenous vein graft repair of the common femoral vein we utilized the spiral vein graft technique. Excluding one early death from associated injuries and one superficial femoral venous injury managed by ligation without postoperative complications, 17 of 23 (74 percent) femoral venous repairs were judged patent postoperatively (13 confirmed by venography and 4 by noninvasive testing). The adjuvant use of intermittent pneumatic calf compression and low molecular weight dextran appears to have been beneficial in maintaining patency of the femoral venous repairs. Early clinical follow-up demonstrated the presence of edema in 6 of 8 cases (75 percent) initially treated by ligation or complicated by postoperative occlusion. Early postoperative edema, present in 4 of 17 (24 percent) patients with patent venous repairs, had resolved by the time of discharge. We recommend routine repair of femoral venous injuries. When significant edema or ischemia develop following obligatory venous ligation or postoperative occlusion of a venous repair, revision or venous bypass should be considered.

Impedance plethysmography. Noninvasive diagnosis of deep venous thrombosis and arterial insufficiency

The versatility of impedance plethysmography (IPG) in the diagnosis of arterial and venous disease was evaluated in the clinical setting. Eighty-eight consecutive patients suspected of acute or chronic deep venous thrombosis (DVT) and undergoing ascending venography were evaluated using IPG. Venous capacitance (VC) and venous outflow (VO) were expressed as a per cent impedance change (% delta I). The evaluation was considered as abnormal if the VC was less than 1.85% delta I and the VO less than 0.95% delta I. The overall accuracy was 90 per cent with a sensitivity of 92 per cent and specifity of 93 per cent. Arterial blood flow (ABF) was measured in normal volunteers (20 limbs) and patients with intermittent claudication (20 limbs) and rest pain (16 limbs). Resting ABF (cc/100 ml/min) did not differ (P greater than 0.05) in the normal volunteer (4.3 +/- 0.4) and patients with intermittent claudication (4.6 +/- 0.5), but both were significantly greater (P less than 0.05) than ABF in patients with rest pain (3.2 +/- 0.2). Peak ABF during reactive hyperemia (RH) was significantly greater (P less than 0.001) in normal volunteers (24.8 +/- 1.6) than in claudicators (10.5 +/- 1.3), and both flows were significantly greater (P less than 0.0001) than the peak ABF in patients with rest pain (5.3 +/- 0.5). IPG may be used in the assessment of arterial and venous disease. It provides a sensitive test with which to screen patients with suspected DVT. In addition, it is a valuable adjunct in differentiating normal limbs from those with intermittent claudication and/or rest pain.

Differential patency and limb salvage for polytetrafluoroethylene and autogenous saphenous vein in severe lower extremity ischemia

Polytetrafluoroethylene (PTFE) was compared to autogenous saphenous vein (ASV) in 133 femoropopliteal and femorotibial or peroneal bypass procedures performed in limb salvage during a 4-year period. PTFE was used as an alternative prosthesis in the absence of a suitable ASV. Sixty-nine femoropopliteal bypasses (FPBPs) were studied--36 with ASV and 33 with PTFE. Sixty-four femorotibial or peroneal bypasses were categorized as femoral distal bypasses (FDBPs)--34 with ASV and 30 with PTFE. With a 3-year clinical follow-up, cumulative function rate (CFR)--patency including thrombectomy--for FPBP with ASV was 65% as compared to 53% for PTFE (P greater than 0.05), whereas the limb salvage rate (LSR) was 75% with ASV and 56% for PTFE (P greater than 0.05). However for FDBP, the GFR was 55% for ASV and 7% for PTFE, whereas the LSR was 55% with ASV and 26% for PTFE. The cumulative patency rate (CPR)--initial thrombosis of a prosthesis as an endpoint--was not significantly (P greater than 0.05) different from CFR, suggesting that thrombectomy with or without distal anastamotic revision does not contribute to patency of the PTFE prosthesis in these limb salvage cases. PTFE was a suitable alternative to ASV for FPBP; however, PTFE is recommended for FDBP in selected cases only.

Real-time B-mode ultrasonography of the femoral arteries: comparison to contrast arteriography

Forty-five patients with symptomatic peripheral vascular disease were studied with a high-resolution, real-time B-mode echo imaging system for visualization of the femoral arteries. Common femoral and superficial femoral arteries were visualized in over 88 per cent of cases, whereas the profunda femoris artery was demonstrated in only about one-third of cases. Stenotic lesions (+ or - 20% of arteriographic assessment) were identified in two-thirds of cases. Prostheses and grafts in the proximal and medial cases. Prostheses and grafts in the proximal and medial thigh were well visualized. Anatomic information provided by B-mode imaging will complement functional assessments of lower extremity vascular insufficiency.

Oculoplethysmography and pulsed Doppler ultrasonic imaging in diagnosis of carotid arterial disease

The individual and combined diagnostic accuracy rates for fluid-filled oculoplethysmography and pulsed Doppler ultrasonic imaging in the detection of extracranial carotid artery insufficiency were calculated. Results of the two techniques were compared with those of contrast arteriograms which were available for 109 patients, 210 arteries, for computations of sensitivity and specificity. Sensitivities for oculoplethysmography and ultrasonic imaging were 84 and 87 per cent, while specificities were 87 and 81 per cent, respectively. These values were not significantly, p greater than 0.05, different. Results of oculoplethysmography and ultrasonic imaging agreed in four-fifths of the arteries, producing a sensitivity of 98 per cent and a specificity of 97 per cent. In the remaining arteries, the results of the two tests did not agree, resulting in a sensitivity of 71 per cent and a specificity of 79 per cent. Fluid-filled oculoplethysmography and pulsed Doppler ultrasonic imaging are diagnostic tests of comparable accuracy which, when used together, provide accurate hemodynamic and anatomic information in the diagnosis of extracranial carotid arterial disease.

Below-knee bypass for limb salvage. Comparison of autogenous saphenous vein, polytetrafluoroethylene, and composite dacron-autogenous vein grafts

Autogenous saphenous vein was used preferentially for 92 below-knee bypass procedures (44 femoral-distal popliteal and 48 femoral-distal tibial or peroneal) performed for limb salvage in 87 adult male patients during a 30-month period of study. When a saphenous vein was unavailable or of unsuitable length or diameter, we randomly used expanded polytetrafluoroethylene (PTFE) and composite Dacron-autogenous vein (DV) grafts. With good run-off, all grafts have remained patent. However, with poor run-off, cumulative patency by the life table method decreased to 54% for autogenous saphenous vein and 45% for PTFE, which was not significantly different. All composite DV grafts used with poor run-off became occluded within the first ten months of the study. We continue to recommend use of autogenous saphenous vein for revascularization of the ischemic lower extremity. When a suitable saphenous vein is unavailable, PTFE is a satisfactory alternative graft that is superior to composite DV grafts.

Diagnostic potentialities of enzyme-linked immunosorbent assay in tuberculosis using purified tuberculin antigen

Delayed hypersensitivity tests with tuberculin or purified tuberculin (PPD) have been used for detection of tuberculous infection. The present paper describes an enzyme-linked immunosorbent assay (ELISA) for detection of PPD-antibodies in tuberculosis patients. The ELISA test was positive in nearly 80% of cases having bacteriological evidence of tuberculosis. The test could also detect PPD-antibodies in 66% of the cases not showing bacteriological evidence of tuberculosis. The potentiality of the test in the immunodiagnosis of tuberculosis is discussed.