Abbreviated method of determining vein volume in balloon-controlled vein ablation.

Traditional surgical ligation and stripping for the treatment of saphenous vein incompetence has been replaced by minimally invasive alternative treatments during the last five years. Endovenous ablation with radiofrequency (RP) and laser (EVL) have proven to be safe, durable, and widely accepted by patients. Catheter-delivered sclerotherapy (CDS) with foam and liquid for ablation of the great saphenous vein is also under investigation. In this technique, vein volume must be measured accurately by ultrasound just prior to the procedure and can require up to 11 diameter measurements. The purpose of this study was to identify an abbreviated method of determining vein volume to expedite associated endovenous procedures. Seventy-five veins were treated in 55 subjects with catheter-directed sclerotherapy in a three-center clinical study using a standardized protocol. Vein volume was carefully calculated by determining vein diameter over the Treatment Length in 4 cm intervals. These measurements were compared to vein volume calculations where only three measurements were taken. Our results suggest that the abbreviated method is capable of significantly reducing the number of diameter measurements without sacrificing accuracy. We found the method produced a vein volume that fell within 1 mL or 15% of the actual vein volume in 80% of cases. The abbreviated method cannot be used with accuracy in veins that are Erratic.

Risk stratification and outcomes of transluminal endografting for abdominal aortic aneurysm: 7-year experience and long-term follow-up.

PURPOSE: To determine early and late outcomes of transluminal endografting (TE) in patients with abdominal aortic aneurysm (AAA), stratified by predicted risk of procedure-related mortality with conventional operation. MATERIALS AND METHODS: A retrospective study was conducted in consecutive risk-stratified AAA patients undergoing TE at a not-for-profit cardiovascular referral center from March 1994 through November 2000 with follow-up through February 2001. With use of conventional risk strata (0 = low, 1 = minimal, 2 = moderate, and 3 = high), predicted procedure-related mortalities were 0%-1% in stratum 0 (n = 40), 1%-3% in stratum 1 (n = 118), 3%-8% in stratum 2 (n = 116), and 8%-30% in stratum 3 (n = 31). Main outcome measures were: (i) TE procedural success, (ii) procedure-related mortality, (iii) major nonfatal complications, (iv) composite adverse outcome (ii + iii), (v) length of stay (LOS), (vi) freedom from AAA rupture, (vii) late survival, (viii) late complications, and (ix) endoleaks and their classification and management. RESULTS: Women were significantly less likely than men to qualify for and undergo endografting: 24 of 91 (26.4%) women underwent TE, compared to 281 of 684 (41.1%) men. Of 305 attempted TE procedures, 291 (95.4%) were successful, four (1.3%) were urgently converted to open repair, and 10 (3.3%) were aborted. Procedure-related mortalities occurred in eight cases (2.6%) overall and one of 40 (2.5%), one of 118 (0.8%), four of 116 (3.4%), and two of 31 (6.5%) cases for risk strata 0-3, respectively. Perioperative survivors were significantly younger than nonsurvivors (74.3 y +/- 9 vs 81.6 y +/- 5.1; P =.0087). Forty-six patients (15.1%) had major complications. Composite adverse outcome was worse for patients in stratum 3 than those in stratum 1 (P =.0296) and those in strata 0, 1, and 2 combined (P =.026). Procedure-related mortality declined with institutional experience, from 4% among the first 100 patients undergoing TE to 1% among the last 105. For strata 0-3, median LOS were 2, 3, 3, and 4 days, respectively. Seventy patients (22.9%) had 75 endoleaks, of which 30 necessitated additional procedures, 17 self-resolved, and 22 were untreated as of March 1, 2001. Five patients with endoleak died of unrelated causes. One late-onset type IA endoleak (26 mo) resulted in the only AAA rupture and death in the follow-up period among the 291 patients who underwent successful transluminal endograft implantation. Actuarial survival rates at 1 year after TE were 90.3% +/- 1.9% for the overall study group and 97.5% +/- 2.5%, 94% +/- 2.5%, 86.9% +/- 3.3%, and 81.3% +/- 7.7% for risk strata 0-3, respectively. At 5 years, overall actuarial survival was 69.6% +/- 6.1%. Thirty-eight late deaths were attributable to post-TE AAA rupture (n = 1), AAA rupture late after failed TE with no further treatment (n = 1), other cardiovascular disorders (n = 7), cancer (n = 15), other causes (n = 10), and unknown causes (n = 4). Late deaths occurred in risk strata 0-3 at the following rates: two of 40 (5%), 10 of 118 (8.5%), 16 of 116 (13.8%), and 10 of 31 (32.3%), respectively (stratum 0 vs stratum 3, P =.0017; stratum 1 vs stratum 3, P =.003). CONCLUSIONS: TE is safe and confers durable protection against AAA rupture in treated populations. Still, protection is not absolute in patients with endoleaks, because late AAA enlargement and even rupture can occur. Given current knowledge, technology, and practice, careful patient selection and close surveillance of patients after implantation of transluminal endografts is essential.

Heparin-bonded grafts induce platelet aggregation in the presence of heparin-associated antiplatelet antibodies.

PURPOSE: Thromboresistant synthetic grafts should decrease the frequency of graft thromboses and could be useful in bypasses to small arteries and to arteries with compromised flow. Heparin-bonded grafts (HBG) have been developed. Studies were done to determine whether the heparin bond is permanent and whether the HBG would aggregate platelets in the presence of heparin-associated antiplatelet antibodies (HAAbs). METHODS: We studied an 8 mm HBG from company A (HBGA) and 8 mm and 6 mm HBGs from company B (HBGB-8 and HBGB-6), none of which is available for clinical use in the United States. Five 1 cm long segments of HBGA, HBGB-8, and HBGB-6 were incubated for 24 hours in 5 ml of plasma, 10 ml of saline, or 10 ml of Ringer's lactate. After incubation, 1 ml was obtained from each solution and assayed for heparin. Segments of each graft that leached off an equivalent of 1 U of heparin/ml (i.e., 1 mm2 of HBGA, 5 mm2 of HBGB-8, and 20 mm2 of HBGB-6) were incubated with 0.15 ml of plasma with HAAbs (six samples per graft) for 30 minutes at 25 degrees C. The grafts were removed, and 0.1 ml of normal-donor, platelet-rich plasma was added. The samples were placed in an aggregometer and allowed to react until positive aggregation occurred or 27 minutes had elapsed. Segments of non-heparin-bonded polyester grafts served as controls. RESULTS: Heparin leached off all grafts in plasma (mean values: HBGA, 83.4 U of heparin/ml; HBGB-8, 4 U of heparin/ml; HBGB-6, 6.2 U of heparin/ml). In normal saline, the mean heparin concentrations were lower (HBGA, 10.8 U of heparin/ml; HBGB-8, 0 U of heparin/ml; HBGB-6, 0.01 U of heparin/ml. The mean heparin concentration after incubation in Ringer's lactate were 10 U of heparin/ml for HBGA, 0 U of heparin/ml HBGB-8, and 0.22 U of heparin/ml HBGB-6. All of the HBGs induced platelet aggregation inHAAb-positive plasma. None of the control grafts induced platelet aggregation in HAAb-positive plasma. CONCLUSIONS: All HBGs leached heparin into plasma, and all induced platelet aggregation in the presence of HAAbs. The possibility of sensitizing patients to heparin leeching from a HBG with the activation of platelets and secondary thrombosis strongly suggests that HBG be used with great caution. Other methods for inducing graft thromboresistance should be developed.

Reduced morbidity and mortality rates of the heparin-induced thrombocytopenia syndrome.

PURPOSE: We reported a 61% morbidity rate and a 23% mortality rate for the heparin-induced thrombocytopenia (HIT) syndrome in 1983. We subsequently reported in 1987 that with early recognition, immediate cessation of the administration of heparin, and platelet function inhibition, the morbidity rate could be reduced to 23% and the mortality rate to 12%. One hundred recent cases of patients with heparin-associated antiplatelet antibodies (HAAb) have been reviewed to determine whether aggressive screening, early diagnosis, and alternate management could further reduce morbidity and mortality rates. METHODS: The consecutive records of 100 patients with positive platelet aggregation tests were reviewed. Sixty-six patients were male. The patients' ages ranged from 23 days to 92 years. The patients were from vascular (28), cardiothoracic (42), and other (30) services. HIT was suspected in patients who received heparin and had falling platelet counts, platelet counts less than 100,000/mm3, or new thromboembolic or hemorrhagic events. RESULTS: Heparin was not offered to six patients with known HAAb. Twelve patients were successfully treated with antiplatelet therapy and limited reexposure to heparin, and 75 patients were successfully treated with early diagnosis and prompt cessation of heparin. Alternate forms of anticoagulation therapy were used selectively. Seven patients had 11 complications. Three of the seven patients were treated successfully with warfarin anticoagulation and aspirin (2) or with aspirin alone (1). A fourth patient was treated with thrombectomy, hematoma evacuation, and aspirin. A fifth patient underwent thrombolysis and coronary angioplasty in addition to receiving warfarin and aspirin. The sixth patient required two thrombectomies and warfarin. A seventh patient required two thrombectomies and aspirin. HIT was responsible for one of 17 deaths. CONCLUSION: A 7.4% morbidity rate and a 1.1% mortality rate have been achieved in patients with HAAb by aggressive screening, early recognition of HIT, and prompt cessation of the administration of heparin. Platelet function inhibitors and other anticoagulants, including nonreacting low molecular weight heparin, are important adjuncts in the management of the thromboembolic disorders associated with HIT.

In vitro culture and labeling of neural cell aggregates followed by transplantation.

Septal, cortical, or whole brain fetal (E15-17) cells were dissociated and cultured in serum-supplemented Dulbecco minimum essential medium under rotating culture conditions. Preincubation and exposure to cytosine arabinoside was utilized to produce "neuron-rich" cultures. Fluorescent latex microbeads were added to cultures at seeding time or early after aggregate formation. All cell types were found to incorporate the fluorescent beads, although apparently not to the same extent. Two- to five-day-old aggregates tended to attach and grow neurites after their transfer to poly-l-lysine- or Matrigel-coated dishes under stationary conditions. Early aggregates transplanted to the hippocampus of adult rats developed into identifiable grafts, with fluorescent-labeled cells. We conclude that "young" neural cell aggregates maintain their ability to undergo two basic phenomena for cellular interaction, i.e., attachment and neuritic growth. Floating aggregates may provide a convenient cellular condition whenever culturing of neural cells is to be used before grafting them into a host animal.

Resistencia vascular e volume pulmonar no pulmao isolado do cao. / Pulmonary volume and vascular resistance in isolated dog lung

A resistencia vascular pulmonar como funcao do fluxo sanguineo foi estudada no lobo isolado do pulmao do cao em diferentes volumes pulmonares. A pressao venosa foi mantida constante e o lobo perfundido com sangue autologo. Os resultados indicam que: a) resistencia vascular pulmonar diminui quando o fluxo sanguineo aumenta; b) a resistencia vascular pulmonar diminui inicialmente, entre o colapso pulmonar total e o volume moderado e aumenta marcadamente entre o volume moderado e a inflacao completa. Os autores sugerem que os dados morfometricos de Weibel poderiam explicar a queda da resistencia vascular na fase inicial de inflacao pulmonar. Durante essa fase as dobras dos capilares septais referidas por Weibel tendem a desaparecer, diminuir a resistencia vascular pulmonar