Biomedical subjects

John K Karwowski

Publications and source records attributed to John K Karwowski.

5 recordsLinked to original sources

PubMed2006

Long-term thrombotic recurrence after nonoperative management of Paget-Schroetter syndrome.

BACKGROUND: The purpose of this study was to determine the clinical predictors associated with long-term thrombotic recurrences necessitating surgical intervention after initial success with nonoperative management of patients with primary subclavian vein thrombosis. METHODS: Sixty-four patients treated for Paget-Schroetter syndrome from 1996 to 2005 at our institution were reviewed. The standardized protocol for treatment includes catheter-directed thrombolysis, a short period of anticoagulation, and selective surgical decompression for patients with persistent symptoms. First-rib resection was performed in 29 patients (45%) within the first 3 months, with a success rate of 93%. The remaining 35 patients (55%) were treated nonoperatively and constitute this study's population. RESULTS: Of the 35 patients with successful nonoperative management, 8 (23%) developed recurrent thrombotic events of the same extremity at a mean follow-up time of 13 months after thrombolysis (range, 6-33 months). These eight patients subsequently underwent first-rib resection with a 100% success rate without further sequelae at a mean follow-up time of 51 months (range, 2-103 months). The other 27 patients remained symptom free at a mean follow-up interval of 55 months (range, 10-110 months). Bivariate analyses determined that the use of a stent during the initial thrombolysis was associated with thrombotic recurrence (P = .05). The recurrence group was also significantly younger than the asymptomatic group (22 vs 36 years; P = .01). Sex, being a competitive athlete, a history of trauma, whether the dominant arm was affected, time of delay to lysis, initial clot burden, response to original lysis, use of adjunctive balloons or mechanical thrombectomy devices, residual stenosis on venography, length of time on warfarin, and patency of the vein on follow-up duplex examination were all characteristics not associated with long-term recurrence after nonoperative management. CONCLUSIONS: Conservative nonoperative management of primary subclavian vein thrombosis can be successfully used with acceptable long-term results. A younger age (<28 years old) and the use of a stent during initial thrombolysis are factors associated with long-term recurrent thrombosis. Younger patients should be offered early surgical decompression, and the use of stents without thoracic outlet decompression is not indicated.

Adult↗

PubMed2006

Simulation improves resident performance in catheter-based intervention: results of a randomized, controlled study.

OBJECTIVES: Surgical simulation has been shown to enhance the training of general surgery residents. Since catheter-based techniques have become an important part of the vascular surgeon's armamentarium, we explored whether simulation might impact the acquisition of catheter skills by surgical residents. METHODS: Twenty general surgery residents received didactic training in the techniques of catheter intervention. Residents were then randomized with 10 receiving additional training with the Procedicus, computer-based, haptic simulator. All 20 residents then participated in 2 consecutive mentored catheter-based interventions for lower extremity occlusive disease in an OR/angiography suite. Resident performance was graded by attending surgeons blinded to the resident's training status, using 18 procedural steps as well as a global rating scale. RESULTS: There were no differences between the 2 resident groups with regard to demographics or scores on a visuospatial test administered at study outset. Overall, residents exposed to simulation scored higher than controls during the first angio/OR intervention: procedural steps (simulation/control) (50 +/- 6 vs. 33 +/- 9, P = 0.0015); global rating scale (30 +/- 7 vs. 19 +/- 5, P = 0.0052). The advantage provided by simulator training persisted with the second intervention (53 +/- 6 vs. 36 +/- 7, P = 0.0006); global rating scale (33 +/- 6 vs. 21 +/- 6, P = 0.0015). Moreover, simulation training, particularly for the second intervention, led to enhancement in almost all of the individual measures of performance. CONCLUSION: Simulation is a valid tool for instructing surgical residents and fellows in basic endovascular techniques and should be incorporated into surgical training programs. Moreover, simulators may also benefit the large number of vascular surgeons who seek retraining in catheter-based intervention.

Angiography↗

PubMed2002

Flow loading induces macrophage antioxidative gene expression in experimental aneurysms.

OBJECTIVE: Reactive oxygen species may act as proinflammatory mediators in abdominal aortic aneurysm (AAA) disease. Flow loading increases antioxidative enzyme expression and limits reactive oxygen species production in vascular smooth muscle cells in vitro, limits experimental AAA enlargement in rodent models, and is indirectly associated with reduced clinical AAA risk. We attempted to determine the mechanism or mechanisms by which flow loading limits AAA enlargement. METHODS AND RESULTS: Rodent AAAs were flow loaded via femoral arteriovenous fistula creation. Aortic wall shear stress and relative wall strain were significantly higher in flow-loaded rodents. Flow loading reduced AAA diameter by 26% despite evidence of flow-mediated aortic enlargement proximal to the aneurysmal segment. Messenger RNA from AAA tissue was harvested for cDNA labeling and hybridization to a 384-clone DNA microarray. Twenty-nine genes were differentially expressed (relative intensity/relative intensity of control ratio >1.5 and <0.67) in flow-loaded compared with normal flow AAA tissue, including heme oxygenase 1 (HO-1). Increased HO-1 expression was confirmed via reverse transcriptase-polymerase chain reaction. Immunohistochemistry localized HO-1 expression to infiltrative macrophages. alpha-Tocopherol was found to be as effective as flow loading in limiting AAA enlargement. Flow loading and alpha-tocopherol therapy reduced AAA reactive oxygen species production. CONCLUSIONS: Flow loading may attenuate AAA enlargement via wall shear or strain-related reductions in oxidative stress.

Animals↗

PubMed2002

Intraoperative ultrasonography improves identification of recurrent thyroid cancer.

BACKGROUND: Surgical resection is the only curative treatment option for locoregional recurrence of well-differentiated thyroid cancer that does not trap radioiodine. We hypothesized that intraoperative ultrasonography would aid in the localization of recurrent thyroid cancer and would enhance the ability to perform a complete resection. METHODS: Between June 2000 and October 2001, 13 patients with recurrent, scan-negative, papillary thyroid cancer were explored by using intraoperative ultrasonography. RESULTS: All patients had identification and resection of recurrent papillary thyroid cancer. Eleven patients had a complete resection, and 2 patients had incomplete resection as a result of local invasion. Ultrasound was required for identification of tumor in 7 patients and included all patients with a history of external beam radiotherapy. In 6 of these 7 patients, the tumor was paratracheal or invasive into the trachea or thyroid cartilage. In 11 patients with detectable serum thyroglobulin preoperatively, the level demonstrated a decline in 10 patients and became undetectable in 7 patients. CONCLUSIONS: Intraoperative ultrasonography is a useful method to identify nonpalpable, locoregional recurrences of thyroid cancer. Ultrasound was particularly helpful in patients who had previous external beam radiotherapy and in the identification of tumor nodules of 20 mm or less that were invasive or adherent to the airway.

Adult↗

PubMedDate not supplied

Needle track seeding of papillary thyroid carcinoma from fine needle aspiration biopsy. A case report.

BACKGROUND: Dissemination of tumor cells from needle biopsy has been observed in a wide range of tumor types. Fine needle aspiration (FNA) biopsy has become accepted as the first-line test in the evaluation of thyroid nodules. Local recurrence of thyroid cancer from needle track seeding is an extremely rare complication of thyroid FNA. CASE: A 59-year-old woman developed local recurrence of papillary thyroid carcinoma three years after FNA of the primary cancer. Local metastases developed in the skin and sternocleidomastoid muscle. The location of the recurrent cancer and the linear relationship of the metastases indicated that local recurrence was due to needle track seeding at the time of FNA. CONCLUSION: Needle track seeding has been recognized as a possible, albeit rare, complication of FNA of thyroid cancer. Although proper FNA technique can reduce the potential for needle track seeding, its occurrence is an unavoidable complication of FNA evaluation of thyroid malignancies.

Biopsy, Needle↗