Biomedical subjects

T M Bergamini

Publications and source records attributed to T M Bergamini.

At least 19 recordsLinked to original sources

PubMed2001

Does cell-saver blood administration and free hemoglobin load cause renal dysfunction?

Our aim was to evaluate the impact of cell-saver volume and free hemoglobin load on renal dysfunction. Intraoperative blood salvage was conducted in standard fashion, and in each case a sample of the blood was removed for testing. Outcome data on individual patients were collected during a 6-year period (1992-1998). The total amount of free hemoglobin each patient received was calculated. Renal dysfunction was defined as a rise in creatinine level of 1.0 mg/dL above baseline. There were a total of 125 patients who received salvaged blood. The free hemoglobin concentration ranged from 19 to 304 mg/dL (mean, 87.5 mg/dL). Patients were stratified into groups on the basis of the total free hemoglobin received, and the Kruskal-Wallis test demonstrated a difference between groups in the prevalence of renal dysfunction (P < 0.001). A total of 15 patients (12%) had significant postoperative renal dysfunction. There was an association between the amount of free hemoglobin load and subsequent renal dysfunction. This may warrant further study toward establishing policies and limits regarding maximal free hemoglobin blood.

Adult↗

PubMed2000

Vascular problems of the pelvis.

Vascular tumors of the pelvis are a rare, diverse group of neoplasms. These benign or malignant tumors can arise from the endothelium, smooth muscle cells, or pericytes of the arterial venous or lymphatic walls. They are rarely diagnosed by physical examination but more commonly seen with imaging studies such as computed tomography, magnetic resonance imaging, or angiography. Benign and malignant tumors can be differentiated pathologically by the two major anatomic characteristics of vascular channel formation and the regularity of endothelial cell proliferation. This review will focus on the clinical presentation, diagnosis, treatment, outcomes, and surgical approaches to benign and malignant vascular tumors of the pelvis.

Angiography↗

PubMed2000

Foramen of Morgagni hernia: surgical consideration.

We have recently encountered two patients with foramen of Morgagni hernias both of whom were symptomatic and required repair. Both patients did well following repair. Symptomatic Morgagni hernias should be repaired to reduce complications in later life.

Adolescent↗

PubMed1999

Descending thoracic aortobifemoral bypass: an alternative approach for difficult aortic revascularization.

Descending thoracic aortobifemoral bypass is an alternative inflow operation in cases in which standard aortobifemoral or axillobifemoral bypass is not an option. We performed descending thoracic aortobifemoral bypass for failed inflow operations in four patients, prior abdominal/pelvic radiation in two patients, poor quality distal aorta (extensive atherosclerotic disease or poor tissue quality) in two patients, and abdominal sepsis in two patients. Eight have had excellent results with patency at a mean follow-up of 38 months. There was no limb loss. One patient died of organ failure, and one patient with hypercoagulability developed a graft clot. A literature review disclosed that a descending thoracic aortobifemoral bypass was reported to have been performed in 203 patients, with most cases reported in the last decade. This procedure was the primary inflow operation in 42 per cent of cases. Indications for the operation included failed aortic grafts (38%), "hostile" abdomen (21%), infected aortic grafts (18%), and other (23%). The patency rate was 95 per cent at 6 months. Few long-term results are known, but the results appear to be durable. Descending thoracic aortobifemoral bypass is a useful operation in highly selected circumstances in which conventional methods of aortic reconstruction are not available.

Anastomosis, Surgical↗

PubMed1998

Bacterial products primarily mediate fibroblast inhibition in biomaterial infection.

PURPOSE: The stimulation of fibroblast growth is essential for the normal healing and tissue integration of biomaterials. The local elevation of proinflammatory mediators in infected perigraft fluid (PGF) may inhibit this growth. We sought to determine whether infected PGF inhibited fibroblast growth, and, if so, whether this was primarily dependent on the biomaterial, bacteria, or host. METHODS: In vivo Dacron or expandable polytetra-fluoroethylene (ePTFE) grafts, sterile or colonized with slime-producing (RP-62A, viable or formalin-killed) or nonslime-producing (RP-62NA) Staphylococcus epidermidis (1 x 10(7) CFU/cm2), were implanted in Swiss Webster mice, and the PGF was harvested at 7 and 28 days. Antibodies to tumor necrosis factor alpha, interleukin 1 alpha, interferon gamma (7 micrograms/day), and indomethacin (50 micrograms/day) were administered by microinfusion pumps for 7 days and the PGF was harvested. Inhibition of the proinflammatory mediators was confirmed by enzyme-linked immunosorbant assay. The nontreated, heat-treated, or trypsin-digested in vivo PGF was incubated with an in vitro [3H]thymidine murine fibroblast (ATCC CCL-12) proliferation assay. RESULTS: Fibroblast inhibition was significant at 7 and 28 days with infected PGF incubation compared with sterile and was not dependent on bacterial slime production or viability. Dacron sterile PGF did not significantly inhibit fibroblasts compared with control, whereas sterile ePTFE stimulated (P < 0.05) fibroblasts. Treatment of the PGF with proinflammatory cytokines, heat, and trypsin failed to reverse fibroblast inhibition in the infected state. CONCLUSION: Biomaterial infection is associated with fibroblast inhibition that is dependent primarily on bacterial products and not the host or biomaterial. Conservative intervention strategies for graft infection need to address the problem of poor healing as well as bacterial clearance.

Animals↗

PubMed1998

May-Thurner syndrome: management by endovascular surgical techniques.

May-Thurner syndrome is a condition in which there is impaired venous return due to compression of the left common iliac vein by the overlying right common iliac artery. The impedance of flow occurs both by the compressive force of the artery against the vein and by resultant intraluminal web formation inside the vein. Because of the mechanical nature of the obstruction, conservative management of these patients has resulted in poor outcomes. Typically, operative therapy is recommended and perused via various approaches. We have recently treated a 15-year-old patient with this disorder utilizing endovascular surgical techniques with an excellent outcome. A 1-year follow-up is presented.

Adolescent↗

PubMed1998

Current options in prosthetic vascular graft infection.

Debate continues over which procedure is the best treatment for prosthetic graft infections. We retrospectively reviewed the medical records at our institution for all vascular graft infections that occurred from 1985 to 1995 to evaluate their occurrence, treatment, and outcome. Twenty-four patients had prosthetic graft infections. The average patient age was 62 years, and 67 per cent of the patients studied were men. The initial operation was for treatment of occlusive disease in 92 per cent of the patients, and aortofemoral bypasses were the most common procedures performed (15 of 24 patients, 63%). The average interval from graft implantation to presentation of infection was 29 months. In lower-extremity bypasses, the site of infection was most commonly in the groin (87%). Gram-positive organisms, including coagulase-negative Staphylococcus (32%) and Staphylococcus aureus (28%), were the most frequently isolated bacteria. Thirty procedures were performed for management of the graft infections. Extra-anatomic bypass was associated with no recurrent graft infections. Graft preservation was successful in two cases of early S. aureus infection (less than 1 year after original procedure), and in situ graft replacement was successful in all four cases of late-appearing coagulase-negative Staphylococcus infection (more than 1 year after original procedure). Both treatments failed in all five cases of Gram-negative infection (P = 0.008 by Fisher's exact test). The overall mortality and amputation rates were 17 per cent and 21 per cent, respectively, without significant differences between the treatment modalities. Extra-anatomic bypass remains the best treatment for prosthetic graft infection. In situ replacement and graft preservation treatments should be selective and based on presentation of the infection and the type of pathogenic organism.

Amputation, Surgical↗

PubMed1998

Comparison of sequential compression devices and foot pumps for prophylaxis of deep venous thrombosis in high-risk trauma patients.

Multiple-trauma patients are at increased risk for deep venous thrombosis (DVT) but are also at increased risk of bleeding, and the use of heparin may be contraindicated. Sequential pneumatic compression devices (SCDs) are an alternative for DVT prophylaxis. However, lower extremity fracture or soft tissue injury may preclude their use. In these circumstances, foot pumps (FPs) are often substituted, yet little clinical data exist to support their use. We identified 184 consecutive high-risk trauma patients who received DVT prophylaxis with compression devices. We reviewed demographic data, mechanism of injury, Injury Severity Score, injury pattern, and method of prophylaxis. Generally, SCDs were preferred, but FPs were substituted in patients with lower extremity injuries. Occurrences of DVT or pulmonary embolism were also noted. Patients surviving less than 48 hours were excluded. SCDs were used in 118 patients (64%) and FPs in 66 patients (34%). There were no differences in age, Injury Severity Score, or presence of shock on admission. As expected, FP patients were more likely to have lower extremity fractures (65 vs 26%; P < 0.05) and were also more likely to have associated pelvic fracture (59 vs 25%; P < 0.05) and chest injury (61 vs 26%, P < 0.05). There was no difference in the incidence of head injury, although SCD patients had more severe head injuries (Glasgow Coma Score, 7.9 vs 10.5; P < 0.05). The overall incidence of DVT was 5.4 per cent (10 of 184), with no differences between the two groups (SCD 7% vs FP 3%). Three patients had a pulmonary embolism (FP, two; SCD, one), none of which were fatal. Compression devices provide adequate DVT prophylaxis with a low failure rate (3-8%) and no device-related complications. FPs appear to be a reasonable alternative in the high-risk trauma patient when lower extremity fractures precludes use of SCD.

Adult↗

PubMed1997

Staphylococcus epidermidis graft infection is associated with locally suppressed major histocompatibility complex class II and elevated MAC-1 expression.

OBJECTIVES: To determine the local cellular immune response in a series of human patients with Staphylococcus epidermidis prosthetic graft infection and to use a murine model to investigate the response in polytef (PTFE) and in a nonslime-producing S epidermidis variant. METHODS: Externally supported Dacron and PTFE grafts, either sterile or colonized with slime (RP-62A)- or nonslime (RP-62NA)-producing S epidermidis (10(7) colony forming units/cm2) were implanted in a dorsal subcutaneous pocket of Swiss Webster mice (Taconic, Germantown, NY). The grafts were harvested at 7, 10, 14, and 28 days with local bacterial and leukocyte counts obtained. Perigraft and blood monocyte major histocompatibility complex class II (MHC-II) (immune antigen) and membrane attack complex type 1 (MAC-1) (glycoprotein) expression were analyzed by flow cytometry in the murine model and in 3 patients representing 4 Dacron graft infections. RESULTS: The human infected Dacron perigraft monocytes revealed a suppressed MHC-II and elevated MAC-1 expression, and early correlation with the murine model was seen. No notable perigraft monocyte MHC-II suppression occurred in the infected PTFE graft. The reciprocal relationship in Dacron between monocyte MAC-1 and MHC-II expression was exaggerated with the lack of slime production. Bacterial clearance was variable. Supranormal expression was observed at 1 month in sterile Dacron but not in PTFE grafts. CONCLUSIONS: Staphylococcus epidermidis infection is associated with local cellular immune suppression in Dacron but not PTFE grafts. Slime-producing S epidermidis induced a lesser cytotoxic-phagocytic response than the nonslime variant. The reduced immunologic response to slime-producing S epidermidis may explain, in part, its indolent nature and resistance to eradication.

Animals↗

PubMed1997

Prostaglandin E2 modulates monocyte MHC-II (Ia) suppression in biomaterial infection.

Staphylococcus epidermidis biomaterial infection is associated with local cellular immune suppression measured by a depressed monocyte (M phi) Ia expression. The purpose of this study was to define the effect of proinflammatory mediators on Ia expression and bacterial clearance in experimental biomaterial infection. A 1-cm-long Dacron tube graft, sterile or colonized with Staphylococcus epidermidis (1 x 10(7) cfu/ml2), was implanted in Swiss-Webster mice. Perigraft fluid was collected at 7, 10, 14, and 28 days and assayed by enzyme-linked immunoassays for tumor necrosis factor alpha (TNF alpha), interleukin (IL)-I alpha, IL-4, IL-10, and prostaglandin E2 (PGE2). Grafts were sonicated and plated for quantitative growth. In vivo effector inhibitions was accomplished with anti-TNF alpha, anti-IL-1 alpha antibodies (7 micrograms/24 hr), or indomethacin (50 micrograms/24 hr) via an Alzet 7-day microinfusion pump. M phi Ia expression was determined by flow cytometry. A significant elevation of TNF alpha, IL-1 alpha, and PGE2 was found during the first 10 days in the infected compared with sterile (P < or = 0.05) grafts and correlated with maximal Ia suppression. Neither IL-4 nor IL-10 was significantly different in the sterile or infected perigraft fluid. Indomethacin completely prevented M phi Ia suppression, while anti-IL-1 alpha only partially (94%) prevented M phi Ia suppression with a corresponding decrease in PGE2 production in infected grafts. Anti-TNF alpha increased PGE2 production by 189% and was associated with depressed M phi Ia expression. Indomethacin treatment improved mean graft-adherent bacterial clearance by 54% at 7 days and 75% at 28 days compared with control (not significant). Interleukin-1 alpha but not TNF alpha increases PGE2 production which modulates M phi Ia suppression. To improve treatment of biomaterial infections, local immunomodulation of PGE2 and IL-1 alpha is promising.

Animals↗

PubMed1997

Carotid endarterectomy results from a state vascular society. Kentucky Vascular Surgery Society Study Group.

PURPOSE: This study analyzes the results of carotid endarterectomy (CEA) performed statewide by members of the Kentucky Vascular Surgery Society (KVSS). METHODS: Between September 1, 1991 and September 1, 1993, 22 vascular surgeons in the KVSS submitted 1490 CEAs to the vascular registry. Follow-up data were obtained on 986 (66%) CEAs performed on 889 patients (average age, 68 years). RESULTS: Carotid endarterectomy was performed on 505 men and 384 women. Indications for operation were asymptomatic carotid stenosis (43%), transient ischemic attack (TIA; 27%), amaurosis fugax (13%), stroke (11%) and nonhemispheric symptoms (6%). A total of 384 cases had primary closure, and 602 had patch reconstruction following CEA. The combined stroke-mortality rate was 2.3% (10 strokes and 13 deaths). The combined stroke-mortality rate of CEA was 2.1% for patients treated by academic surgeons and 2.3% for those treated by community surgeons. Deaths were due to stroke (4), sepsis (5), cardiac complications (2), intracerebral hemorrhage (1) and cancer (1). Five patients had postoperative TIAs. After CEA, duplex scan surveillance was performed in 629 (64%) patients, with 23 (3.6%) residual/recurrent stenosis (10, 50%-75%; 13, 75%-99%) detected; 5 undergoing reoperation. CONCLUSIONS: These data support the efficacy and safety of CEA performed by a large number of vascular surgeons in both community and academic practice.

Aged↗

PubMed1997

Venous thromboembolism in the high-risk trauma patient: do risks justify aggressive screening and prophylaxis?

OBJECTIVE: Deep venous thrombosis (DVT) and pulmonary embolism (PE) are considered to be a major source of morbidity and mortality among trauma patients. Several reports have identified high-risk patients with recommendations for management ranging from frequent duplex scanning to placement of prophylactic inferior vena cava (IVC) filters. We reviewed our experience with a large trauma population to determine whether such approaches are justified. METHODS: We analyzed 2,868 consecutive trauma admissions over 22 months and identified 280 patients (10%) in high-risk groups who survived > or = 48 hours: (1) severe closed head injury with mechanical ventilation > or = 72 hours, (2) closed head injury with lower extremity fractures, (3) spinal column/cord injury, (4) combined pelvic and lower extremity fractures, and (5) major infrarenal venous injuries. The remaining nonthermal injury patients constituted the low-risk group. RESULTS: There were 280 high-risk patients, 213 of whom (76%) received prophylaxis with compression therapy. There were 12 cases of DVT (5%) with four nonfatal PE (1.4%). Six patients (2%) had therapeutic IVC filters inserted and only one patient had prophylactic placement. There were 38 deaths in this group, attributable primarily to severe closed head injury or spine injuries, and none were caused by PE. In the 2,249 low-risk patients, there were three cases of DVT (0.1%, p < 0.05 vs. high risk) and no PE (p < 0.05 vs. high risk). CONCLUSIONS: Although these patients were at increased risk for thromboembolic events, the overall incidence of DVT was still extremely low with no apparent PE deaths. In our patient population, aggressive screening and prophylactic IVC filters would not have benefited 95% of "high-risk" patients without DVT and would not have prevented any deaths. We could not identify any population, except perhaps venous injuries, where such expensive and potentially harmful maneuvers seemed justified. Our experience with DVT and PE does not support either aggressive screening or prophylactic IVC filters as the standards of care.

Adolescent↗

PubMed1997

Abdominal vascular injuries.

Trauma surgeons are occasionally faced with patients with abdominal vascular injuries. Important surgical issues in the successful management of these injuries require a thorough knowledge of the abdominal vascular anatomy and techniques of vascular repair, that surgical exploration be performed without delay, that the vascular injury be exposed rapidly with control of hemorrhage upon entering the abdomen, that efforts be made to reestablish perfusion initially to the structures at the highest risk of anoxic injury, and an understanding that it is occasionally necessary to perform temporary procedures while the general condition of a patient is being stabilized, with subsequent definitive care. The primary goal in the management of these patients should be hemorrhage control rather than maintenance of blood flow. The principles of abbreviated laparotomy with planned reoperation should be used in some patients with major abdominal vascular injuries. The decision to reestablish vascular continuity at a later time should balance anticipated functional outcome against potential complications.

Abdomen↗

PubMed1997

Phagocytosis and oxidative-burst response of planktonic Staphylococcus epidermidis RP62A and its non-slime-producing variant in human neutrophils.

The ability of bacterial organisms to produce an extracellular polysaccharide matrix known as slime has been associated with increased virulence and delayed infections in various prosthetic implants. Within a biofilm, this slime may protect the embedded bacteria from host defense mechanisms, especially phagocytosis by polymorphonuclear leukocytes. To determine whether planktonic Staphylococcus epidermidis is protected in a similar way, a novel flow cytometric assay was performed, measuring ingestion and adherence during phagocytosis and the production of superoxide during oxidative burst. Hydrophobicity was determined by hydrophobic interaction chromatography. Slime-producing S. epidermidis RP62A and its phenotypic variant, non-slime-producing RP62A-NA, were compared. The results showed increased phagocytosis of RP62A at 2, 5, 10, and 30 min; increased adherence of RP62A at 30 s and 30 min; and increased superoxide production of RP62A after 2 min. Decreased hydrophobicity of RP62A over RP62A-NA was correlated with a hydrophilic slime coat. The data argue that the host aggressively combats slime-producing S. epidermidis. This biological phenomenon is potentially important during bacteremia to prevent further adhesion, accumulation, and the genesis of a bacterial biofilm on implants or tissue surfaces.

Animals↗

PubMed1997

Intraoperative duplex scanning reduces both residual stenosis and postoperative morbidity of carotid endarterectomy.

To evaluate the effect of intraoperative duplex scanning (IDS) on the incidence of perioperative and postoperative strokes as well as residual and recurrent stenosis, we reviewed 141 patients who underwent 152 consecutive carotid endarterectomies (CEAs) between July, 1990 and June, 1995. Follow-up of 129 cases, with a mean follow-up of two years, revealed no perioperative deaths and three strokes for a combined perioperative stroke-death rate of 2.3 per cent. In 50% (64 of 129) of the CEAs, intraoperative duplex scans were obtained based on the attending surgeon's preference. We noted that the incidence of residual stenosis (>50% stenosis on the first duplex after CEA) was significantly lower in those undergoing IDS (3/64) versus those without IDS (13/65) (P < 0.05; risk ratio 0.31; 95% confidence interval 0.11, 0.91). IDS resulted in a modification of the internal carotid reconstruction in 9 per cent (6 of 64) of the cases with no resulting postoperative strokes or residual/recurrent stenosis. There was no significant difference in the frequency of recurrent stenosis (>50% stenosis after a normal duplex) in the two groups (3 of 64 with vs 2 of 65 without). Of patients not undergoing intraoperative scanning, four underwent redo CEA for symptomatic residual stenosis due to a retained intimal flap in the internal carotid artery. There were three strokes observed within 30 days of the initial CEA, all of which occurred in patients who did not undergo IDS at their initial operation. We conclude that IDS can identify technical defects following internal carotid reconstruction, thereby reducing the incidence of both residual stenosis and postoperative morbidity in patients undergoing CEA.

Carotid Stenosis↗

PubMed1997

Surgical implications of hypercoagulable syndromes.

The advent of improved diagnostic tests for primary hypercoagulability has led to increased recognition of this entity as a problem in surgical patients. We treated 20 patients with documented evidence of increased coagulability from 1975 to 1995. Clinical presentations included venous (16) and arterial (4) thrombosis. Symptoms usually occurred early in life (mean age, 38 years) and developed spontaneously without a secondary inciting event or factor. Deficiencies in naturally occurring anticoagulant proteins including antithrombin III (n = 7), protein C (n = 3), and protein S (n = 1) were seen, as were problems with lupus anticoagulant (n = 2) and anticardiolipin antibody (n = 4) deficiencies. Treatment of these patients is difficult, and results are often suboptimal. A total of 12 vascular reconstructions were required in 5 of the 20 patients; 11 eventually failed. Patients with primary venous thrombosis were often successfully treated with anticoagulant therapy in the short term but fared less well in the long term. There were three deaths directly related to thrombotic complications. Surgeons may encounter patients with primary hypercoagulable syndromes. The diagnosis should be expected in patients with unusual patterns of vascular disease or arterial or venous thrombosis without cause or at an early age, or in patients with recurrent or migratory clotting. Evaluation of this population, although expensive, is indicated. Treatment with chronic anticoagulation is also generally indicated. Arterial reconstruction in this subset of patients usually leads to a poor outcome.

Adult↗

PubMed1997

Blunt popliteal artery trauma: a challenging injury.

Blunt popliteal artery trauma is a challenging injury, particularly when associated with major soft tissue damage. We reviewed our experience with this injury to determine 1) the incidence of vascular injury associated with fractures and/or dislocations about the knee, 2) the incidence of limb loss, and 3) factors associated with amputation. We treated 37 patients with 38 blunt popliteal artery injuries and either fractures about the knee or posterior knee dislocations. Patients who underwent primary amputations were excluded. The incidence of popliteal artery injuries with fractures about the knee was 3 per cent, whereas 16 per cent of patients with posterior knee dislocations had vascular injuries (P < 0.05). Amputations were required in 14 of the 38 injured limbs (36%). None of these patients had a pulse or Doppler signal on admission, and 13 had major soft tissue injury. No patient with a pulse or Doppler signal lost a limb (P < 0.05). Limb loss was primarily related to limited venous outflow and/or severe infection in damaged tissue. Failure of the arterial repair rarely led to amputation, particularly in recent years. Two patients with angiographically proven arterial injuries were treated nonoperatively without complications. The incidence of vascular injuries associated with fractures about the knee is low, but somewhat higher with posterior knee dislocations. The overall 9 per cent rate of positive angiograms suggests that a selective approach may be indicated. The amputation rate remains high, but it has improved with an integrated, multidisciplinary team approach. In patients without a pulse or Doppler signal and with severe soft tissue injuries, primary amputation may be appropriate.

Adolescent↗

PubMed1997

The surgical implications of primary hypercoagulable states.

Primary hypercoagulable states are hereditary disorders that result in arterial and venous thromboses. The purpose of this report is to present three patients with hypercoagulable states, and offer current guidelines for diagnosis and treatment. Primary hypercoagulable disorders such as antithrombin III, protein C and protein S deficiencies, fibrinolytic disorders such as decreased plasminogen levels and plasminogen activator deficiency, and antiphospholipid syndromes such as anticariolipin antibody and lupus anticoagulants will be reviewed. We will emphasize clinical characteristics that should prompt evaluation for hypercoagulation, appropriate laboratory tests for hypercoagulable disorders, and treatment. Other secondary and recently investigated hypercoagulable disorders, including heparin-associated thrombocytopenia, homocystinemia, lipoprotein (a), plasminogen activator inhibitor, and factor V Leiden, will also be reviewed.

Adolescent↗