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Biomedical subjects

K Valji

Publications and source records attributed to K Valji.

42 records · Page 3Linked to original sources
PubMedDate not supplied

Use of a direct thrombin inhibitor (argatroban) during pulse-spray thrombolysis in experimental thrombosis.

PURPOSE: To evaluate the effectiveness of intravenous and intrathrombic injection of the thrombin inhibitor argatroban during pulse-spray pharmacomechanical thrombolysis (PSPMT) in experimental venous thrombosis. MATERIALS AND METHODS: Clots were produced in the inferior vena cava in 52 rabbits by placement of steel coils and balloon injury to the vessel wall. Two days later, clots were treated with PSPMT. Several treatment methods were used: intrathrombic saline, intrathrombic tissue plasminogen activator (t-PA), intrathrombic t-PA with intrathrombic and intravenous heparin, intrathrombic t-PA with intravenous argatroban, and intrathrombic t-PA with intrathrombic and intravenous argatroban at two different doses. After treatment, the rabbits were killed and residual clot was weighed. Pretreatment clot weight was estimated and clot lysis was assessed. RESULTS: PSPMT with t-PA and adjunctive intrathrombic heparin resulted in greater lysis than PSPMT with only t-PA (percentage of residual clot, 59% +/- 14 vs 81% +/- 28; P = .02). Addition of intravenous argatroban did not increase lysis, but adjunctive intrathrombic argatroban significantly increased lysis at low doses (37% +/- 16; P = .02) and high doses (34% +/- 6; P = .006) compared with t-PA and intrathrombic heparin. CONCLUSION: In a rabbit model of venous thrombosis, the use of intrathrombic argatroban during PSPMT with t-PA significantly improved clot lysis.

Animals↗
PubMedDate not supplied

Does cervical spinal cord injury induce a higher incidence of complications after prophylactic Greenfield inferior vena cava filter usage?

PURPOSE: To determine whether acute cervical spine injury represents a risk factor for complications from prophylactic placement of current generation Greenfield inferior vena cava (IVC) filters. MATERIALS AND METHODS: A retrospective chart review performed during a 7-year period identified 11 patients with acute cervical spinal cord injuries who underwent prophylactic Greenfield IVC filter insertion. Specific complications evaluated included symptomatic pulmonary embolism (PE), migration, filter base diameter changes, caval perforation, and thrombosis. The amount of migration and changes in filter base dimension were compared statistically with a control population of IVC filter patients (n = 16) without cervical spine injuries. RESULTS: Filter migration (> 10 mm) was the most common complication (46%). Migration usually is caudally directed (64%), may occur early (36% moved > 10 mm within a 30-day period), and is often asymptomatic. The prevalence of filter migration greater than 30 mm was 27%. The average amount of migration for the subpopulation under study was greater than that seen with the control population (P < .05). No statistically significant change in filter base size occurred. The study population also had rates of PE (9%-18%), caval perforation (9%), and IVC thrombus formation (18%) that were higher than the rates in historical controls. The majority of patients with these complications received vigorous pulmonary toilet (46%), including "quad coughs" or cardiopulmonary resuscitation (18%). CONCLUSIONS: Acute cervical spinal cord injury and the associated supportive care may be associated with an increased risk for caudal IVC filter migration, IVC perforation, caval thrombosis, and PE.

Adult↗
PubMedDate not supplied

IVC filter tilt and asymmetry: comparison of the over-the-wire stainless-steel and titanium Greenfield IVC filters.

PURPOSE: A comparison of tilting, caval coverage, asymmetry, and insertion problems with the over-the-wire stainless-steel and titanium versions of the Greenfield filter. MATERIALS AND METHODS: The study compared 104 stainless-steel and 141 titanium Greenfield inferior vena cava (IVC) filter insertions. The angle the sheath and deployed filter made relative to the cava, as well as filter strut distribution, were determined from spot films. The proportionate caval coverage was computed from the cavogram (anteroposterior projection). Mean filter tilts, subgrouped by insertion site, and caval coverage were compared with the Student t test, whereas strut patterns were analyzed with a contingency table. RESULTS: The filter caval and sheath caval angles correlated. The filter caval angles varied with insertion site, but were lowest with a right jugular approach. Caval coverage was identical with both designs. The stainless-steel version resulted in a more uniform distribution of struts in comparison with the titanium version. The incidence of insertion problems was not significantly different between the filter types. CONCLUSIONS: While IVC filter tilting was not improved with the newer design, the pattern of struts was more uniformly symmetric with the stainless-steel device. The right jugular insertion site was associated with the lowest filter caval angles and the most symmetric pattern of struts.

Chi-Square Distribution↗
PubMedDate not supplied

Importance of Doppler analysis of transmitted atrial waveforms prior to placement of central venous access catheters.

PURPOSE: To assess the sensitivity of Doppler flow analysis of the axillary and internal jugular veins to screen for clinically occult thoracic central veno-occlusive disease and predict successful placement of central access catheters. MATERIALS AND METHODS: Sixty-seven patients underwent both duplex sonographic evaluation of the axillary and internal jugular veins and contrast venography prior to placement of a central venous catheter. Duplex evaluation included visual evidence of veno-occlusive disease as well as the presence or absence of normal transmitted polyphasic atrial waves and respiratory variation of flow. Diagnostically adequate venograms were available for comparison with the duplex sonograms in 168 access routes (access site plus downstream conduit veins). The contrast venograms and sonograms were compared by using retrospective blinded interpretation. Outcome of attempted catheter placement was tabulated. RESULTS: Directed sonographic imaging of the axillary and internal jugular vein allowed detection of access route veno-occlusive disease with a sensitivity of only 33.3%. Alternatively, when Doppler flow analysis found atrial waveforms that were not polyphasic, central conduit occlusive disease was detected with a sensitivity of 79.6%. Monophasic atrial waveforms were associated with a 25% failure rate of catheterization due to central vein occlusive disease, whereas polyphasic atrial waveforms were correlated with a 100% success rate for catheter placement. CONCLUSION: In asymptomatic patients, sonographic imaging alone misses most instances of central veno-occlusive disease. However, Doppler flow analysis of transmitted atrial waveforms substantially improved the sensitivity. A normal polyphasic atrial waveform virtually excludes the possibility of a more central venous occlusion or stenosis greater than 80% and ensures an adequate route for central venous catheterization.

Adult↗