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Biomedical subjects

M W Mewissen

Publications and source records attributed to M W Mewissen.

At least 19 recordsLinked to original sources
PubMed2001

Catheter-directed thrombolysis for lower extremity deep vein thrombosis.

The elimination of the embolic potential of existing thrombus, the restoration of unobstructed flow, the prevention of further thrombosis, and the preservation of venous valve function are the ideal goals of therapy for acute deep vein thrombosis (DVT). Meeting these goals will not only prevent pulmonary embolism but will also minimize the long-term sequelae of venous hypertension and the development of postthrombotic syndrome (PTS). Treatment strategies aimed at eliminating or reducing the risk of PTS should focus on preserving valvular function and eliminating the risk of continued venous obstruction after acute DVT. Thrombolytic agents are an attractive form of early therapy because they have the ability to eliminate obstructive thrombus in the deep veins and should therefore help provide protection against PTS. The perceived benefits of early and rapid recanalization in preserving valve function has been the basis for the use of lytic therapy to treat acute DVT.

Catheters, Indwelling↗
PubMed1999

Endovascular therapy of iliac arteries: routine application of intraluminal stents does not improve clinical patency.

Our objective in this study was to review our experience with endovascular therapy of iliac artery occlusive disease over the past decade, and to compare the results of angioplasty alone with the addition of endovascular stents to these procedures. This report details a retrospective analysis of clinical data on 141 consecutive patients with iliac artery occlusive disease, treated by balloon angioplasty alone, or with the addition of intraluminal stents. The procedures analyzed included 58 common iliac artery interventions (26 angioplasties and 32 stent insertions) and 83 external iliac artery procedures (43 angioplasties and 40 stent insertions). Early and continued success, and their components, are reported and compared according to published standards. While endovascular therapy of iliac artery occlusive disease is effective in relieving symptoms, clinical patency rates are lower than those reported for direct reconstruction. Primary stent placement has not enhanced clinical patency in the iliac arteries, and the selective insertion of these devices for more complicated angioplasty procedures seems warranted.

Adult↗
PubMed1999

Catheter-directed thrombolysis for lower extremity deep venous thrombosis: report of a national multicenter registry.

PURPOSE: To evaluate catheter-directed thrombolysis for treatment of symptomatic lower extremity deep venous thrombosis (DVT). MATERIALS AND METHODS: From a registry of patients (n = 473) with symptomatic lower limb DVT, results of 312 urokinase infusions in 303 limbs of 287 patients (137 male and 150 female patients; mean age, 47.5 years) were analyzed. DVT symptoms were acute (< or = 10 days) in 188 (66%) patients, chronic (> 10 days) in 45 (16%), and acute and chronic in 54 (19%). A history of DVT existed in 90 (31%). Lysis grades were calculated by using venographic results. RESULTS: Iliofemoral DVT (n = 221 [71%]) and femoral-popliteal DVT (n = 79 [25%]) were treated with urokinase infusions (mean, 7.8 million i.u.) for a mean of 53.4 hours. After thrombolysis, 99 iliac and five femoral vein lesions were treated with stents. Grade III (complete) lysis was achieved in 96 (31%) infusions; grade II (50%-99% lysis), in 162 (52%); and grade I (< 50% lysis), in 54 (17%). For acute thrombosis, grade III lysis occurred in 34% of cases of acute and in 19% of cases of chronic DVT (P < .01). Major bleeding complications occurred in 54 (11%) patients, most often at the puncture site. Six patients (1%) developed pulmonary emboli. Two deaths (< 1%) were attributed to pulmonary embolism and intracranial hemorrhage. At 1 year, the primary patency rate was 60%. Lysis grade was predictive of 1-year patency rate (grade III, 79%; grade II, 58%; grade I, 32%; P < .001). CONCLUSION: Catheter-directed thrombolysis is safe and effective. These data can guide patient selection for this therapeutic technique.

Female↗
PubMed1997

Impact of peripherally inserted central catheters on phlebitic complications of peripheral intravenous therapy in spinal cord injury patients.

We investigated the impact of peripherally inserted central catheter (PICC) placement in spinal cord injury patients at high risk for infusion phlebitis. The rate and etiology of phlebitis was investigated in two phases. During Phase I, peripheral IV cannulae and conventional central venous catheters (CVC) were used. During Phase II, patients identified to be at risk for phlebitis received PICCs. The number of peripheral IVs, CVCs and PICCs was tabulated for both phases of the study. Technical, infectious and thrombotic complications were studied prospectively for PICCs and retrospectively for CVCs. We found the rate of phlebitis was 16.5 percent and 2.4 percent for Phases I and II, respectively (p = 0.0002). Three infections occurred in 38 PICCs and one infection was documented in 13 conventional CVCs. The number of peripheral IVs and conventional CVCs was reduced significantly from Phase I to Phase II. No procedural complications, catheter sepsis or clinically apparent venous thrombosis occurred. In conclusion, PICCs reduced the rate of phlebitis thresholds with a low complication rate and reduced the use of peripheral IVs and conventional CVCs.

Catheterization, Central Venous↗
PubMed1997

Pulmonary artery thrombolysis and stenting after a bilateral sequential lung transplantation.

Bilateral sequential lung transplantation was complicated by pulmonary artery anastomotic stenosis and bilateral pulmonary thromboemboli. Pulmonary artery thrombus was eliminated by intrathrombotic but not by systemic administration of urokinase. The pulmonary emboli resulted in localized pulmonary infarctions, supporting the need for thrombolytic intervention to restore pulmonary perfusion in the absence of collateral bronchial blood flow after lung transplantation. Pulmonary artery stenosis was relieved by endovascular stenting, avoiding an early reoperative procedure. This case suggests that direct administration of thrombolytic agent may be superior to intravenous administration in the treatment of pulmonary thromboemboli. Pulmonary arterial anastomotic stenoses after lung transplantation can be relieved by endovascular procedures.

Adult↗
PubMed1996

Fibrin sleeve stripping for salvage of failing hemodialysis catheters: technique and initial results.

PURPOSE: To evaluate percutaneous fibrin sleeve stripping (PFSS) to prolong functional patency in failing hemodialysis catheters. MATERIALS AND METHODS: Forty PFSS procedures were performed in 24 catheters in 23 consecutive patients with an inadequate blood flow rate (< 200 mL/min) during hemodialysis. The fibrin sleeve was mechanically stripped off the shaft of the catheter with a snare introduced via the common femoral vein. Durability of PFSS was determined with life-table analysis. RESULTS: Median time from catheter placement to initial failure was 3.5 months (range, 5 days to 22 months). The technical success rate for PFSS was 100%; initial patency was restored in 39 of 40 procedures (98%), and no symptomatic pulmonary embolism occurred. Primary patency after single PFSS was 45% at 3 months and 28% at 6 months (median added patency, 2.8 months). Postprocedure secondary patency with multiple PFSS procedures was 83% at 3 months and 72% at 6 months (P = .01) (overall catheter patency, 90% at 6 months and 81% at 1 year [P < .001]). CONCLUSION: Multiple PFSS procedures can prolong patency in hemodialysis catheters with a fibrin sleeve.

Adult↗
PubMed1996

Interventional procedures in the intensive care unit patient.

Image-guided interventional techniques have markedly altered the management of many cardiothoracic problems in the intensive care unit. These techniques are less invasive, more patient friendly, and cost-effective. This article covers venous line placement and management, transpleural and transpulmonary biopsy and drainage procedures and interventions for variceal bleeding, massive hemoptysis, massive pulmonary embolism, and veno-occlusive disease.

Biopsy, Needle↗
PubMed1995

Detection of pulmonary embolism in patients with unresolved clinical and scintigraphic diagnosis: helical CT versus angiography.

OBJECTIVE: This study was designed to prospectively compare helical CT with pulmonary angiography in the detection of pulmonary embolism in patients with an unresolved clinical and scintigraphic diagnosis. SUBJECTS AND METHODS: Twenty patients with an unresolved suspicion of pulmonary embolism were evaluated with contrast-enhanced helical CT and with selective pulmonary angiography. An average of 11 hr separated the two studies. The CT scans were obtained during one 24-sec or two 12-sec breath-holds. CT scans were interpreted without knowledge of the results of scintigraphy or angiography. Selective pulmonary angiograms were obtained with knowledge of the findings on the ventilation/perfusion scan only. The sensitivity and specificity of CT were compared with those of angiography for central vessels (segmental and larger) only and for all vessels. RESULTS: Eleven of the 20 patients had proved pulmonary embolism (seven in central vessels and four in subsegmental vessels only). When only central vessels were analyzed, CT sensitivity was 86%, specificity was 92%, and the likelihood ratio was 10.7. However, when subsegmental vessels were included, CT results were 63%, 89%, and 5.7, respectively. CONCLUSION: In our subset of patients, helical CT was only 63% sensitive. Subsegmental emboli are difficult to diagnose. Pulmonary angiography remains the study of choice. CT has a limited role in the evaluation of acute pulmonary embolism.

Acute Disease↗
PubMed1992

The role of duplex scanning versus angiography in predicting outcome after balloon angioplasty in the femoropopliteal artery.

Duplex-derived velocity measurements were used to assess the hemodynamics of 64 femoropopliteal arterial sites in 59 patients after angiographically successful percutaneous transluminal balloon angioplasty. With use of angiography as the gold standard, percutaneous transluminal balloon angioplasty was judged to be successful if (1) evidence existed of a "split" caused by intimal dissection and splitting of atherosclerotic plaque; and (2) no significant diameter-reducing residual stenosis was observed at the percutaneous transluminal balloon angioplasty site. At 1 month, 55 limbs (86%) were hemodynamically and clinically improved by SVS/ISCVS clinical criteria for chronic limb ischemia. Of the 55 percutaneous transluminal balloon angioplasty sites, duplex scanning had identified 40 (63%) sites with a less than 50% diameter-reducing stenosis and 15 (27%) sites with a greater than 50% diameter-reducing stenosis within a week after percutaneous transluminal balloon angioplasty. Independent review of the 55 angiograms taken after percutaneous transluminal balloon angioplasty identified 39 sites (71%) with a split and 16 sites (29%) without. By life-table analysis, a greater than 50% diameter-reducing stenosis predicted a worse clinical outcome (15% at 1 year) compared with the presence of a less than 50% diameter-reducing stenosis (84% at 1 year) (p less than 0.001; log rank test). The presence or absence of an angiographic split was not a predictive factor of percutaneous transluminal balloon angioplasty outcome (split, 61% at 1 year; no split, 62% at 1 year) (p = 0.832; log rank test). The detection of a functional residual stenosis by duplex scanning did not correlate with angiographic appearance, but was predictive of clinical failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Monitoring functional patency of percutaneous transluminal angioplasty.

Duplex scanning and Doppler-derived blood pressure measurements were used to serially monitor lower limb hemodynamics in 73 patients who underwent percutaneous transluminal angioplasty. Ninety percutaneous transluminal angioplasty sites judged technically satisfactory by arteriography were evaluated. Significant hemodynamic improvement was seen in 81 (90%) of the 90 limbs, although both hemodynamic and clinical improvement were achieved in only 77 (86%) limbs. Duplex scanning within 1 week of successful angioplasty identified moderate (20% to 49% diameter reduction) or severe (greater than 50% diameter reduction) residual stenosis in 49 (63%) of 77 balloon-dilated arterial segments. The presence of a greater than 50% diameter reduction residual stenosis predicted further restenosis and late clinical failure (11% success rate at 1 year). When the degree of residual stenosis at the percutaneous transluminal angioplasty site was less than 50% diameter reduction by duplex scanning, the procedure was durable (80% success rate at 2 years), even in patients with critical ischemia, poor runoff, or diabetes mellitus.

Angioplasty, Balloon↗
PubMed1991

Percutaneous intraarterial thrombolysis in the treatment of thrombosis of lower extremity arterial reconstructions.

Vascular grafts may be salvaged with thrombolytic therapy after acute occlusion as an alternative to balloon catheter thrombectomy. From October 1987 to May 1990, 15 arterial bypasses to the lower extremity (infrainguinal saphenous vein [n = 7] or expanded polytetrafluoroethylene [n = 6], and Dacron aortofemoral bifurcation graft limbs [n = 2]) were treated for 30 occulsions with intraarterial urokinase (390,000 IU to 5,808,000 IU) infused from 3 to 40 hours. The origins of 15 graft occlusions were morphologic defects (intimal hyperplasia with anastomotic or conduit stricture), pseudoaneurysm, or progression of disease distal to the graft. Two occlusions were attributed to coagulation disorders. A cause could not be identified for 13 occlusions. Patency was initially restored to all grafts with use of thrombolytic therapy, however, adjunctive surgical thrombectomy to remove persistent thrombus from the graft or outflow vessels was required after six thrombolytic infusions. One graft in the series could not be salvaged leading to below-knee amputation. Graft defects were corrected by balloon angioplasty (n = 7) or surgical revision of the conduit (n = 8). Five significant hemorrhagic complications occurred from the catheter insertion site requiring four emergent surgical procedures and resulting in the death of a fifth patient from a myocardial infarction. This technique allows chemical thrombectomy of branch arteries distal to the graft and inaccessible to a balloon embolectomy catheter, and permits diagnosis of abnormal graft morphology that may be the cause of the graft occlusion. Graft reocclusion can be expected if technical defects in the arterial reconstruction are not revised or hypercoagulable states are not treated.

Angioplasty, Balloon↗
PubMed1991

Transvenous liver biopsy in critically ill patients: adequacy of tissue samples.

In a consecutive series of 33 patients (38 biopsies), the authors analyzed the pathologic specimens obtained with their relatively new transvenous biopsy method. From the point of view of establishing a useful pathologic diagnosis, the method proved worthwhile in the series of predominantly critically ill patients. A specific diagnosis or a later confirmatory tissue diagnosis was achieved in 18 patients, and a strong clinical correlation was achieved in 10 more. There were no complications from this repeatable, technically relatively simple, and safe procedure.

Adult↗
PubMed1990

Symptomatic native arterial occlusions: early experience with "over-the-wire" thrombolysis.

"Over-the-wire" thrombolysis was successfully accomplished in eight patients with symptomatic lower-extremity ischemia. The authors used a 5-F catheter with multiple side holes designed to pulse-spray urokinase directly over the guidance of a 0.035-inch guide wire. The mean occlusion length was 11.5 cm (range, 5-27 cm). Complete thrombolysis was achieved after delivery of a mean of 480,000 IU of urokinase in a mean infusion time of 48 minutes. One embolic complication was successfully treated with the catheter-wire system. No bleeding complications occurred. Over-the-wire thrombolysis is an alternative method of administering urokinase for the treatment of arterial occlusions.

Arterial Occlusive Diseases↗
PubMed1990

Color Doppler sonographic imaging in the assessment of upper-extremity deep venous thrombosis.

Color Doppler flow imaging with linear-array transducers was performed in 130 extremities in 91 patients with suspected upper-extremity deep venous thrombosis. Thrombi were detected in 39 studies (30%). Eighty-four patients had either imaging examinations (22 studies comprising venography in 20 patients, CT in one, and MR imaging in one) or clinical follow-up (99 studies) for correlation. In studies with imaging correlation, the sensitivity of the Doppler studies was 78% and the specificity was 92%. There were two false-negative examinations in which the proximal subclavian vein either could not be imaged or the anatomy was distorted. There was one false-positive color Doppler diagnosis of deep venous thrombosis in a case of partial obstruction of the subclavian vein caused by extrinsic compression. There were no known additional errors in color Doppler imaging in patients who had clinical follow-up. Four cases of isolated superior vena cava or proximal innominate vein obstruction were missed by color Doppler imaging. Color Doppler flow imaging is an accurate, noninvasive method for the evaluation of upper-extremity deep venous thrombosis. Other imaging tests may be required when the color Doppler study is negative and central venous thrombosis is suspected.

Adolescent↗