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Biomedical subjects

V M Bernhard

Publications and source records attributed to V M Bernhard.

At least 55 records · Page 3Linked to original sources
PubMed1988

Canine model for surgical correction of chronic venous hypertension.

A chronic model of venous hypertension was created by iliofemoral venous ligation in the left hindlimb of eight greyhounds (right limb control). Prior to ligation, immediately postligation (T0), and at 2, 4, 6, and 15 weeks postligation (T2-T15), bilateral hindlimb venous pressures were measured at rest. At T2-T15, exercise pressures were measured for 5 min after hindlimb muscle contraction induced under sedation by tetanic (20 sec, 50 Hz, 8 mA) stimulus (S30-S300 sec). Resting and exercise pressures were significantly higher in the ligated hindlimb at all time intervals (resting, P less than 0.001 at T0, T2, T4, T6, and P less than 0.025 at T15; exercise, P less than 0.001 for S30-S300 at T2-T15). In five of the animals at 15 weeks, a cross-femoral venous bypass (CFB) with adjacent adjuvant arteriovenous fistula (AVF) was constructed using autologous external jugular vein. Venous pressures were measured at 2 and 6 weeks post-CFB both at rest and after tetanic muscle stimulation. At 2 weeks, venous pressure in the ligated limb was significantly higher than that in control only after exercise (P less than 0.025 at S30-S120; P less than 0.05 at S150-S180; NS at S240-S300). At 6 weeks, venous pressures were not significantly different at rest or with exercise. All five grafts were patent at 6 weeks. Three of five dogs then successfully underwent ligation of the AVF. At 2 weeks post-AVF ligation there was no difference in resting or exercise venous pressure in the ligated limb compared to control. At 6 weeks post-AVF ligation only two dogs remained for monitoring and in these there was no trend toward venous hypertension in the ligated hindlimb. Graft patency was maintained despite AVF ligation.

Animals↗
PubMed1988

Combined thrombolytic therapy and percutaneous transluminal angioplasty for treatment of complex arterial graft thrombosis--a case report.

Combined catheter-directed thrombolytic therapy followed by percutaneous transluminal angioplasty (PTA) was successfully performed for the treatment of a thrombosed complex mesenteric artery bypass graft resulting from an anastomotic stenosis. Restenosis of the graft due to neointimal hyperplasia was subsequently treated by PTA, with resultant long-term patency. This approach is an attractive alternative to surgical thrombectomy and graft revision, especially in patients who are poor surgical risks owing to concurrent medical problems.

Aged↗
PubMed1988

Hemodynamics of revascularization for iliofemoral venous occlusion: a short-term canine model.

A short-term canine model of lower extremity venous hypertension was created to study the hemodynamics of crossfemoral venous bypass grafts (CFB). Specifically, the hemodynamic effects of bypass conduit diameter and adjunctive arteriovenous fistulas (AVFs) were investigated. Unilateral hind limb venous hypertension was produced by iliofemoral venous ligation in six groups of five greyhounds each. Group I had venous ligation alone. CFBs were constructed in the remaining five groups: group II, 3 mm bypass conduit alone; group III, 3 mm bypass plus sequential AVF; group IV, 3 mm bypass plus caudad AVF; group V, 3 mm bypass plus cephalad AVF; group VI, 6 mm bypass conduit alone. Venous hypertension was significantly reduced by CFB (group II, p less than 0.025; group VI, p less than 0.001); increasing the diameter of the bypass conduit from 3 to 6 mm produced significantly greater graft flow (p less than 0.05), while completely relieving venous hypertension. Addition of adjunctive AVFs significantly augmented graft flow (p less than 0.001) but tended to aggravate ipsilateral venous hypertension (group III, p less than 0.01; group IV increase, NSS; group V, p less than 0.001). During the 4 hours of pressure monitoring, venous hypertension diminished significantly (p less than 0.05) with the sequential AVF but not with the other AVF. We conclude that (1) AVFs may be required for adequate graft flow if a small-diameter (3 mm) bypass conduit is used to relieve venous hypertension; (2) adjunctive AVFs aggravate venous hypertension; (3) sequential AVFs seem to be the most hemodynamically efficacious; (4) AVFs may not be necessary if a large, isodiametric (6 mm) conduit is used.

Anastomosis, Surgical↗
PubMed1988

Gastrointestinal bleeding after aortic surgery. The role of laparotomy to rule out aortoenteric fistula.

The frequency and causes of gastrointestinal (GI) bleeding occurring after aortic surgery were evaluated retrospectively to determine the incidence of aortoenteric fistula (AEF) in relation to other causes and to place in perspective the role of laparotomy for the diagnosis of AEF. Two hundred fifty-three patients in whom aortic prostheses have been inserted were observed for a mean of 46 months. Seventy-four bleeding episodes occurred in 21% of patients between 1 and 108 months after surgery (mean 29 months). Only one AEF appeared that was associated with GI bleeding, for an incidence of 1.4% of bleeding episodes and 0.4% of grafts inserted. No diagnostic workup for GI bleeding was performed for 20 of the 74 episodes and no AEFs were noted in this group during a mean follow-up of 28 months. Diagnostic evaluation was done for the remaining 54 episodes. No cause for bleeding was identified in 16 patients and no AEF developed in this group during a mean follow-up of 26 months. A potential bleeding site was identified in 38 patients, of whom 30 had intrinsic GI lesions and no subsequent evidence of AEF during a mean follow-up of 28 months. Laparotomy for a suspected AEF was recommended for the remaining eight episodes in eight patients and was performed in six patients. An AEF was seen in one patient with abnormality found on preoperative CT scanning; an intrinsic GI lesion was identified in three patients; and no pathologic condition was found in the remaining two (negative laparotomy rate, 33%).(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta, Abdominal↗
PubMed1988

Transcutaneous oxygen and carbon dioxide pressure monitoring to determine severity of limb ischemia and to predict surgical outcome.

Transcutaneous oxygen and carbon dioxide pressure (PO2 and PCO2) foot monitoring was compared with ankle Doppler-derived systolic pressure regarding their respective abilities to discriminate the severity of limb ischemia before vascular reconstruction and to predict surgical outcome early in the postoperative period. Transcutaneous PO2 (tcPCO2), foot-chest tcPO2 index, transcutaneous PCO2 (tcPCO2), foot tcPO2/tcPCO2 index (tcPO2/tcPCO2), ankle Doppler systolic pressure (AP), and ankle-brachial pressure index (ABI) were determined in 89 revascularized limbs. The measurement of tcPO2 and foot-chest tcPO2 was found to be more sensitive to degrees of severity of limb ischemia and more closely associated with the outcome of revascularization than AP and ABI. TcPCO2 and tcPO2/tcPCO2 were not useful in assessment of the vascular patient undergoing reconstructive surgery. Before operation, tcPO2 less than or equal to 22 torr and foot-chest tcPO2 less than or equal to 0.46 indicate severe limb ischemia requiring urgent revascularization. After operation, tcPO2 less than or equal to 22 torr and foot-chest tcPO2 index less than or equal to 0.53 indicate that revascularization is likely to fail. We conclude that tcPO2 monitoring, as a metabolic test of actual tissue perfusion, is a more reliable indicator of preoperative limb ischemia and postoperative outcome of revascularization than hemodynamic, Doppler-derived pressure tests.

Aged↗
PubMed1988

The necessity for long-term antibiotic therapy with positive arterial wall cultures.

The results of treatment after excision of infected arterial grafts were analyzed as a function of aortic/arterial wall cultures and duration of antibiotic therapy in 33 patients. Four patients died during surgery and 29 patients were observed for periods ranging from 2 weeks to 76 months. Negative arterial wall cultures (NAwC) were found in 16 patients, three of whom died of multiple-organ failure and sepsis but none of whom had aortic/arterial disruption/hemorrhage. Positive arterial wall cultures (PAwC) were found in 13 patients, seven of whom received short-term, broad-spectrum antibiotics for less than 10 days (PAwC-STA) and six of whom received long-term culture-specific antibiotic therapy (intravenous therapy for 6 weeks and oral therapy for 6 months) (PAwC-LTA). Five of seven patients in the PAwC-STA group died of aortic disruption or hemorrhage, one patient had severe hemorrhage caused by disintegration of a saphenous vein patch over the common femoral artery, and one patient had a recurrent aortoenteric fistula. There were 10 episodes of arterial disruption/hemorrhage in those seven patients. All episodes of aortic/arterial disruption/hemorrhage occurred in the PAwC-STA subgroup (seven of seven patients) and none occurred in the PAwC-LTA subgroup (none of six patients) (0.005 less than p less than 0.001). The incidence of aortic/arterial disruption/hemorrhage was significantly different between overall PAwC (7 of 13 patients) vs NAwC (none of 16 patients) (0.005 less than p less than 0.001) and NAwC-STA (none of 16 patients) vs PAwC-STA (seven of seven patients) (0.001 less than p less than 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

Prospective comparison of noninvasive techniques for amputation level selection.

This study prospectively compared the following tests for their accuracy in amputation level selection: transcutaneous oxygen, transcutaneous carbon dioxide, transcutaneous oxygen-to-transcutaneous carbon dioxide, foot-to-chest transcutaneous oxygen, intradermal xenon-133, ankle-brachial index, and absolute popliteal artery Doppler systolic pressure. All metabolic parameters had a high degree of statistical accuracy in predicting amputation healing whereas none of the other tests had statistical reliability. Amputation site healing was not affected by the presence of diabetes mellitus nor were the test results for any of the metabolic parameters.

Adult↗
PubMed1987

The impact of multiple operations on the importance of arterial wall cultures.

The present study reviewed arterial culture data from 172 patients undergoing major vascular reconstructions between July 1, 1977, and Dec. 31, 1984. Prosthetic graft infection was documented in 0 of 97 cases (0%) with negative arterial cultures but in six of 75 cases (8%) with positive arterial cultures (chi 2 = 5.84; 0.01 less than p less than 0.025). The data were reanalyzed after the patients were subdivided into two groups on the basis of the numbers of operations: group I (132 patients)--a culture obtained at initial vascular reconstruction--and group II (40 patients)--a culture obtained at a subsequent vascular reconstruction. Positive arterial cultures had no predictive value for graft infection among patients in group I (1 of 57 cases vs. 0 of 75 cases; chi 2 = 0.019), whereas the presence of positive arterial cultures was associated with a significant increase in the incidence of graft infection in group II patients (5 of 18 cases vs. 0 of 22 cases; chi 2 = 4.68; 0.025 less than p less than 0.05). For group I patients, we believe that neither routine arterial culture nor long-term antibiotic therapy for patients with positive arterial cultures is indicated. For group II patients we recommend that routine arterial cultures should be obtained; perioperative antibiotics should be continued until definitive arterial culture information is available; and positive arterial cultures should be treated with a short course of high-dose intravenous antibiotics. Thereafter, long-term treatment of positive arterial cultures with oral antibiotics, although not statistically validated, is probably appropriate.

Arteries↗
PubMed1986

Intraoperative streptokinase. An adjunct to mechanical thrombectomy in the management of acute ischemia.

Streptokinase was injected directly into the arterial tree following balloon-catheter embolectomy on 13 occasions to remove residual thrombus that could not be mechanically retrieved in 12 patients with imminent limb (ten patients) or kidney (two patients) necrosis. Effective lysis, confirmed by arteriography, pulse return, and increased ankle pressures, was achieved in 11 trials (85%). Bleeding complications, minor in three patients and severe in two patients, were ascribed to systemic lysis although other factors were contributory. One of five deaths was related to therapy. Six limbs were salvaged. The average total dose of streptokinase used, 110,000 units, was given in intermittent boluses of 25,000 to 50,000 units injected below a clamp placed to temporarily occlude distal circulation. Safe application of this technique requires intraoperative monitoring of coagulation parameters, aggressive replacement therapy, and prudent patient selection. This preliminary experience suggests that intraoperative lytic therapy (1) is an effective method for clearing thrombus not amenable to mechanical extraction and (2) may improve patency and tissue salvage.

Acute Disease↗
PubMed1986

Six-year prospective multicenter randomized comparison of autologous saphenous vein and expanded polytetrafluoroethylene grafts in infrainguinal arterial reconstructions.

Autologous saphenous vein (ASV) and polytetrafluoroethylene (PTFE) grafts were compared in 845 infrainguinal bypass operations, 485 to the popliteal artery and 360 to infrapopliteal arteries. Life-table primary patency rates for randomized PTFE grafts to the popliteal artery paralleled those for randomized ASV grafts to the same level for 2 years and then became significantly different (4-year patency rate of 68% +/- 8% [SE] for ASV vs. 47% +/- 9% for PTFE, p less than 0.025). Four-year patency differences for randomized above-knee grafts were not statistically significant (61% +/- 12% for ASV vs. 38% +/- 13% for PTFE, p greater than 0.25) but were for randomized below-knee grafts (76% +/- 9% for ASV vs. 54% +/- 11% for PTFE, p less than 0.05). Four-year limb salvage rates after bypasses to the popliteal artery to control critical ischemia did not differ for the two types of randomized grafts (75% +/- 10% for ASV vs. 70% +/- 10% for PTFE, p greater than 0.25). Although primary patency rates for randomized and obligatory PTFE grafts to the popliteal artery were significantly different (p less than 0.025), 4-year limb salvage rates were not (70% +/- 10% vs. 68% +/- 20%, p greater than 0.25). Primary patency rates at 4 years for infrapopliteal bypasses with randomized ASV were significantly better than those with randomized PTFE (49% +/- 10% vs. 12% +/- 7%, p less than 0.001). Limb salvage rates at 3 1/2 years for infrapopliteal bypasses with both randomized grafts (57% +/- 10% for ASV and 61% +/- 10% for PTFE) were better than those for obligatory infrapopliteal PTFE grafts (38% +/- 11%, p less than 0.01). These results fail to support the routine preferential use of PTFE grafts for either femoropopliteal or more distal bypasses. However, this graft may be used preferentially in selected poor-risk patients for femoropopliteal bypasses, particularly those that do not cross the knee. Although every effort should be made to use ASV for infrapopliteal bypasses, a PTFE distal bypass is a better option than a primary major amputation.

Actuarial Analysis↗
PubMed1986

The value of carotid endarterectomy in reducing the morbidity and mortality of recurrent stroke.

Survivors of ischemic stroke are at high risk of sustaining recurrent strokes, which tend to be more severe and are often fatal. Controversy exists regarding whether or not carotid endarterectomy (CEA) achieves its objectives of preventing recurrent stroke and reducing subsequent death in such patients. Therefore, we analyzed the records of 275 consecutive patients who underwent 350 CEAs between 1977 and 1983 and identified 95 patients (34.5%) who had suffered a preoperative stroke, which was the primary indication for operation. All had either full recovery (13.7%) or only mild (63.2%) or moderate (23.1%) neurologic deficits at the time of operation. Patients with severe deficits did not undergo operation. The operations were performed whenever the neurologic recovery had reached a plateau, without a specific interim waiting period between the stroke and the operation. The combined operative morbidity/mortality rate was 2.7% (three patients), both deaths caused by stroke in patients with mild preoperative neurologic deficits and one (0.9%) nonfatal postoperative stroke involving the retina in a patient who also had a mild preoperative deficit. Long-term follow-up averaged 32 months (range, 6 to 72 months). No ipsilateral recurrent strokes occurred during this period after CEA. Life-table analysis revealed a recurrent stroke rate of 3.2% (0.64% per year) and a 5-year survival rate of 81.3%. Patients who were neurologically normal at the time of operation had a cumulative 5-year survival rate of 90.9%. None of the late deaths was due to recurrent stroke.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Endarterectomized superficial femoral artery as an arterial patch.

Eighty-six patients underwent 90 profundaplasties for lower extremity ischemia using endarterectomized superficial femoral artery (ESFA) or vein as an arterial patch. Standard length profundaplasty was performed in 60 limbs and extended profundaplasty in 28. Seventy-two were performed for limb salvage and 18 for severe claudication. Fifty-four limbs underwent inflow reconstruction and profundaplasty, while 36 others had profundaplasty alone. Three-year cumulative patency rates were employed to compare the type of autogenous patch material to the profundaplasty length, operative indications, and procedures. In all groups, ESFA performed as well as vein. Endarterectomized superficial femoral artery patch angioplasty provides comparable long-term results to vein patch in patients undergoing profundaplasty, and demonstrates its durability as a vascular patch in situations where autogenous tissue is required or preferred while preserving the saphenous vein for later use.

Adult↗
PubMed1985

Fine-needle aspiration biopsy in the management of solid breast tumors.

Fine-needle aspiration biopsy (FNA) is a cost-effective and clinically reliable tool in the management of palpable solid breast lesions. Review of 369 FNA biopsy specimens revealed an accuracy of 92%. The sensitivity was 78% and the specificity was 100%. There were no false-positive results. Positive predictive value was 100%, and negative predictive value was 78%. A positive FNA biopsy result, which confirms a clinical (physical examination and mammography) impression of carcinoma, can be the basis for planning and performing a definitive procedure. Despite the absence of false-positive results, we have not proceeded with a definitive surgical procedure if an FNA biopsy result disagreed with our clinical impression. Fine-needle aspiration biopsy may be used to reassure and support both the patient's and the surgeon's decision not to perform a biopsy of "subsuspicious lesions." A negative FNA biopsy result does not exonerate the clinically suspicious lesion.

Biopsy, Needle↗
PubMed1985

External carotid artery reconstruction: its role in the treatment of cerebral ischemia.

Twenty-one patients who underwent 22 external carotid artery reconstructions for cerebral ischemia were reviewed. Ten patients had amaurosis fugax, 9 had hemispheric ischemia, and 2 were asymptomatic. With the exception of one patient, all had ipsilateral internal carotid artery occlusion and either external carotid stenosis or a cul-de-sac of the occluded internal carotid artery. Six patients had ipsilateral common carotid occlusions. The operative technique has been presented. There were no operative strokes or new neurologic deficits. All patients were relieved of symptoms. Patients were followed a mean of 32 months. During follow-up, 3 ipsilateral transient ischemic attacks occurred during the first 3 months. Four strokes occurred (one ipsilateral and three contralateral) from 4 to 33 months postoperatively. Ipsilateral stroke rate by life table analysis was 1 percent per year. These data suggest that external carotid artery reconstruction is a safe, effective, and durable therapeutic alternative for management of patients with cerebral ischemia and an ipsilateral occluded internal carotid artery. External carotid endarterectomy eliminates a potential source of emboli and increases cerebral perfusion. Because of the increase in cerebral blood flow, subsequent extracranial-to-intracranial bypass may be unnecessary.

Adult↗
PubMed1985

Isolated profundaplasty for limb salvage.

Fifty-four patients underwent 56 profundaplasties for limb salvage. All had stenosis greater than 50% in diameter of the deep femoral artery and associated superficial femoral artery occlusive disease. After profundaplasty, ischemic ulcers healed in 9 of 17 (53%) patients. Rest pain was relieved in 6 of 19 (32%) and areas of ischemic necrosis healed in 7 of 20 (35%). Cumulative patency of the deep femoral artery was 49% at 3 years but fell to 21% at 5 years, whereas cumulative limb salvage was 49% and 36%, respectively. Eleven of the required 28 amputations were performed in the immediate postoperative period. Profundaplasty was used to lower the amputation level and preserve the knee joint in six patients. The other five early amputations occurred in severely ischemic limbs without distal vessels suitable for bypass. The profundaplasty remained patent in all 19 patients who underwent below-knee amputation and 16 (84%) became ambulatory with a prosthesis. Hemodynamic data provided by determination of the profundapopliteal collateral index predicted limb salvage in 10 of 11 (91%) of limbs when the index value was less than or equal to 0.19. Other clinical criteria, such as preoperative ankle-brachial index and the presence of diabetes mellitus, had no predictive value. Isolated profundaplasty for limb salvage is an effective first procedure for selected patients and provides a reasonable alternative to primary amputation or high-risk distal bypass. When amputation is inevitable, effective perfusion of the profunda femoris artery is essential for preservation of the knee joint and results in a high degree of functional rehabilitation.

Aged↗