31 PORCINE SKIN-DERIVED STEM CELLS MAY BE A SUPERIOR SOURCE OF DONOR NUCLEI FOR EFFICIENT GENETIC MODIFICATION OF CLONED EMBRYOS

Somatic cell nuclear transfer (SCNT) in pigs relies primarily on the utilization of fetal-derived fibroblast cells, and the resultant clones tend to exhibit a significant level of phenotypic instability, which may be due to epigenetic reprogramming and/or genomic damage in the donor cells. In addition to the compromised phenotypic stability, production of transgenic clones through SCNT is inefficient, because the restricted lifespan of somatic donor cells in culture can be limiting when the genetic modification requires selection. In contrast, stem cells proliferate rapidly and do not undergo senescence at a high rate, so the selection process can be extended. Since there is no report of an embryonic stem cell line derived in the pig that could contribute to the germ line, we decided to investigate the utility of porcine skin-derived stem cells (SSCs). Porcine SSCs were isolated from the skin on the back of day 35 to 50 Yorkshire fetuses. The SSCs were cultured continually in SSCs medium (DMEM/F12 containing B-27, 20 ng mL–1 of epidermal growth factor, and 40 ng mL–1 of basic fibroblast growth factor) at 37.8°C, 5% CO2, 95% air. The SSCs expressed the neural progenitor marker nestin, as well as genes that are critical for pluripotency, such as Oct4 and Stat3. The SSCs proliferated actively in vitro and retained a normal karyotype after long-term culture. Electron microscopy revealed 2 distinct cell types within the spheres; elongated cells at the sphere periphery had invaginated nuclear envelopes and prominent nucleoli, and these cells displayed few, but large elongated mitochondria with transversal cristae as well as large cisternae of rough endoplasmic reticulum. In contrast, the cells in the center of the spheres were predominantly round-shaped, with a large round nucleus or cuboidal. The SSCs can be genetically modified with long-term positive selection, and 50 μg mL–1 G418 appeared to be an appropriate dose of G418 for selection of the transfected SSCs. Finally, NT embryos reconstructed with SSCs showed high rates of pre- and post-implantation development.The cell number in the blastocyst stage embryos derived from cloning with the SSC was significantly higher than those of the blastocysts derived from IVF (28.5 ± 1.9, 16.8 ± 4.0, respectively, P < 0.05), although there was no significant difference in blastocyst formation rates between these groups (21 to 25%). Three of the animals became pregnant in 4 surrogate gilts which received cloned embryos and reached to term. Two healthy male cloned piglets and 1 healthy female cloned piglet are genetically identical to the SSCs. Funding for this study was provided by the National Institutes of Health.

A survey of anesthesiologists' and nurses' attitudes toward the implementation of an Anesthesia Information Management System on a labor and delivery floor

BACKGROUND

An anesthesia information management system (AIMS) is most frequently used in the operating room, but not on labor and delivery (L&D). The purpose of this study is to describe the implementation of an AIMS on L&D and the attitudes of practitioners (anesthesiologists and nurses) toward the system.

METHODS

The anesthesiology survey focused on satisfaction with the L&D AIMS, comparison of the L&D AIMS with a handwritten anesthesia record, and comparison of the L&D AIMS with the operating room AIMS. The nursing survey focused on nursing satisfaction with the L&D AIMS and comparison of the L&D AIMS with a handwritten anesthesia record.

RESULTS

Most anesthesiologists (76%) were satisfied with the L&D AIMS and 73% would not want to revert back to the paper record. However, most anesthesiologists felt the operating room AIMS was either superior or equal to the L&D AIMS. Although few nurses (4%) preferred the anesthesiologists revert back to the handwritten record overall, the nurses were neutral in their assessment of the AIMS. Most of the criticism related to the location of the system; 56% believed it was not in a convenient location and 74% thought the AIMS equipment "got in their way".

CONCLUSIONS

Overall, the anesthesiologists and nurses are satisfied with the L&D AIMS and would not want to switch back to a handwritten record. We conclude that AIMS should not be limited to the operating room setting and can successfully be used in L&D.

33 PRE-AND POST-IMPLANTATION DEVELOPMENT OF EMBRYOS CLONED FROM PORCINE SKIN-DERIVED SPHERE STEM CELLS

Although transgenic animals have been successfully cloned, the process is still inefficient. One of the limitations is the use of somatic donor cells that have a limited lifespan. If a genetic modification is made, the selection process must be initiated and completed rapidly or the cells will undergo senescence. Identification of a stem cell that would proliferate rapidly and not undergo senescence would prove to be very valuable. Here we report attempts at cloning by using porcine skin-derived sphere stem cells to determine if they are a suitable donor cell type. Skin-derived stem cells were isolated from fetal skin and express the neural progenitor marker NES, as well as genes that may be critical for pluripotency such as POU5F1 and STAT3. The skin-derived stem cells proliferate rapidly in vitro and retain a normal karyotype after long-term culture. In the present study, skin-derived stem cells were cultured and frozen in liquid nitrogen from passage 1 to passage 8. To investigate the developmental potential of the skin-derived stem cells, we performed nuclear transfer (NT) and compared their preimplantation developmental efficiency to that of the embryos derived from in vitro fertilization (IVF). Cumulus–oocyte complexes (COCs) were aspirated from antral follicles of ovaries from prepubertal gilts. Approximately, groups of 50-70 COCs were matured in vitro in 500 µL TCM-199 per culture well for 40–44 h at 38.5�C, in a humidified atmosphere of 5% CO2 in air. The donor cells were thawed and cultured one day before NT; skin-derived stem cells were pipetted vigorously in PBS-EDTA to isolate individual cells. For IVF, cryopreserved ejaculated spermatozoa were thawed and washed and then resuspended with fertilization medium (mTBM). The MII oocytes were co-incubated with sperm for 6 h, and then transferred to PZM3 and cultured. For NT and IVF, respectively, the percent cleavage at 48 h in PZM3 was 64.9 � 8.2% (169/208) and 62.1 � 3.1% (94/184) (P > 0.05), the percent blastocysts after 6 days was 21.5 � 5.8% (53/208) and 25.2 � 3.4% (46/184) (P > 0.05), and the number of nuclei per blastocyst was 28.5 � 1.9 (NT, maximum was 58) and 16.8 � 4.0 (IVF, maximum was 31) (P < 0.05). To determine development post-implantation, some cloned embryos were cultured in PZM3 for 15.5 h and an average of 112 cloned embryos were transferred to the oviducts of four naturally cycling gilts on Day 0–1 of standing estrus. Three of the animals were pregnant: one of them farrowed two male piglets on August 14th, with the other two due on September 8th and 9th. Future studies will involve performing NT and ET on skin-derived stem cells from a higher passage number to determine if they would be suitable for genetic modification prior to NT.

Production of endothelial nitric oxide synthase (eNOS) over-expressing piglets

Vascular function, vascular structure, and homeostasis are thought to be regulated in part by nitric oxide (NO) released by endothelial cell nitric oxide synthase (eNOS), and NO released by eNOS plays an important role in modulating metabolism of skeletal and cardiac muscle in health and disease. The pig is an optimal model for human diseases because of the large number of important similarities between the genomic, metabolic and cardiovascular systems of pigs and humans. To gain a better understanding of cardiovascular regulation by eNOS we produced pigs carrying an endogenous eNOS gene driven by a Tie-2 promoter and tagged with a V5 His tag. Nuclear transfer was conducted to create these animals and the effects of two different oocyte activation treatments and two different culture systems were examined. Donor cells were electrically fused to the recipient oocytes. Electrical fusion/activation (1 mM calcium in mannitol: Treatment 1) and electrical fusion (0.1 mM calcium in mannitol)/chemical activation (200 microM Thimerosal for 10 min followed by 8 mM DTT for 30 min: Treatment 2) were used. Embryos were surgically transferred to the oviducts of gilts that exhibited estrus on the day of fusion or the day of transfer. Two cloned transgenic piglets were born from Treatment 1 and low oxygen, and another two from Treatment 2 and normal oxygen. PCR, RT-PCR, Western blotting and immunohistochemistry confirmed that the pigs were transgenic, made message, made the fusion protein and that the fusion protein localized to the endothelial cells of placental vasculature from the conceptuses as did the endogenous eNOS. Thus both activation conditions and culture systems are compatible with development to term. These pigs will serve as the founders for a colony of miniature pigs that will help to elucidate the function of eNOS in regulating muscle metabolism and the cardiorespiratory system.

374 PRODUCTION OF TRANSGENIC CLONED PIGLETS BY USING PORCINE FETAL FIBROBLASTS OVEREXPRESSING ENDOTHELIAL NITRIC OXIDE SYNTHASE

Vascular function, vascular structure, and homeostasis are thought to be regulated in part by endothelial nitric oxide synthase (eNOS). In addition, eNOS plays an important role in modulating metabolism of skeletal and cardiac muscle in health and disease. The pig is an optimal model for human diseases because of the large number of important similarities between the genomic, metabolism, and cardiovascular systems of pigs and humans. The main goal of this study was to produce pigs that carry an endogenous eNOS gene driven by a Tie-2 promoter and tagged with a V5 His tag so that a better understanding of cardiovascular regulation by eNOS can be gained. Nuclear transfer was conducted to create these animals, and the effects of two different oocyte activation treatments and two different culture systems were examined. Mature oocytes were purchased from BoMed, Inc. (Maidson, WI, USA) and enucleated by micromanipulation. Donor cells were injected into the perivitelline space and electrically fused to the recipient oocyte. Treatment 1 consisted of electrical fusion/activation in 1 mM calcium in mannitol; Treatment 2 consisted of electrical fusion in 0.1 mM calcium in mannitol, followed by chemical activation in 200 �M thimerosal for 10 min followed by 8 mM DTT for 30 min. The fusion rate (71% vs. 82%) was lower (P < 0.0001) in Treatment 2 than in Treatment 1. For those oocytes that fused, the cleavage rates (5.9% vs. 0.4%) at 14-18 h were higher (P < 0.0001) for Treatment 2. Fused oocytes were cultured for 12-18 h in 5% O2, 5% CO2, 90% N2 (low oxygen) or 5% CO2 in air (normal oxygen), and were then surgically transferred to the oviducts of gilts that exhibited estrus on the day of fusion or the day of transfer. In February four cloned transgenic piglets were born (birth weights were 495, 595, 965, and 685 g). Two were from Treatment 1 and low oxygen, and the other two were from Treatment 2 and normal oxygen, and all are currently healthy. PCR, RT-PCR, and Western blotting analysis confirmed that the pigs were transgenic, made message, and made the fusion protein. Immunohistochemistry confirmed that the fusion protein localized in the endothelial cells of the placental vasculature from the conceptuses as did the endogenous eNOS. In addition to the transgenic males, four wild-type females were born (birth weights were 585 (this one died on Day 4) 445, 930, and 585 g). All four were from Treatment 2 and low oxygen, and three are healthy. In conclusion, viable piglets were produced from both Treatments 1 and 2, as well as in both high and low oxygen conditions. Thus, both activation conditions and culture systems are compatible with development to term. These pigs will serve as the founders for a colony of miniature pigs that will help to elucidate the function of eNOS in regulating muscle metabolism and the cardiorespiratory system. This work was funded by a grant from the NIH RR18276 and Food for the 21st Century.

381 PRODUCTION OF A TRANSGENIC PIGLET BY A NEW SPERM INJECTION TECHNIQUE

The technique for intracytoplasmic sperm injection (ICSI) has, until now, focused on scoring the tail of the sperm prior to catching and aspiration into the injection pipette. This is in spite of the fact that damage to the head would more closely simulate what occurs during normal fertilization. In addition, to aid in visualizing the injection process so that a reduced volume can be injected, the oocyte is generally centrifuged to clear a portion of the cytoplasm. Thus, with conventional ICSI, the sperm are immobilized with polyvinylpyrrolidone, repeatedly frozen and thawed, treated with DTT or Triton X-100, and severed between the head and tail; the oocyte is centrifuged or activated. All of the above treatments are designed to compensate for the intrinsic defects in conventional ICSI. Our objective was to use a modified ICSI procedure whereby aggressively motile sperm were captured onto the broken tip of an injection pipette and then injected into noncentrifuged oocytes. Damage to the head of the sperm occurred on the pipette or while pushed through the zona pellucida. These procedures are based on the work of Yong et al. 2003 Hum. Reprod. 18, 2390, where they achieved an improvement in development in vitro as compared to conventional methods. Ovaries were collected from prepubertal gilts, and oocytes were aspirated and matured in vitro. Sperm were collected from a transgenic boar carrying the green fluorescent protein (GFP) and frozen. After thawing, aggressively motile sperm were captured and injected through the zona pellucida and into the cytoplasm of the in vitro-matured oocytes. A total of 452 injected oocytes (43-171 oocytes per recipient) were surgically transferred into the oviduct of six surrogate gilts. Two gilts (33%) became pregnant. One gave birth to a healthy male piglet. GFP expression was observed in the nose and hooves by direct epifluorescent examination of the newborn piglet. This pattern of GFP expression is identical to that in non-ICSI-derived GFP pigs in this line. This result showed for the first time that this new sperm injection technique could be used for production of a viable transgenic piglet using in vitro-matured oocytes and frozen-thawed sperm.

101 CRYOPRESERVATION OF PORCINE EMBRYOS DERIVED FROM SOMATIC CELL NUCLEAR TRANSFER

In the production of cloned pigs, a large number of nuclear transfer (NT) embryos generally need to be transferred into a single surrogate. Thus, attempts to conduct embryo transfer can be frustrating when either a synchronized surrogate is not available, or enough NT embryos are not produced. This problem would be solved if one could cryopreserve the porcine nuclear transfer embryos. Cryopreservation of porcine embryos has been successful only for in vivo-derived embryos. In vitro-derived porcine embryos are sensitive to chilling, and this sensitivity has been attributed to the lipid droplets in the cytoplasm. In previous reports, the viability of cyropreserved embryos was improved by removal of lipid drops from the cytoplasm. Therefore we designed a procedure to cryopreserve cloned blastocysts by a combination of the open pulled straw (OPS) vitrification method with removal of lipid drops from the oocyte. In vitro-matured MII oocytes were enucleated, and centrifuged (10 000 rpm, 5 min) to polarize the lipid droplets. This was followed by removal of the polarized lipid droplets and transfer of a donor fetal-derived fibroblast cell into the perivitelline space by micromanipulation. After electrical activation and fusion, the NT embryos were cultured in PZM-3 medium with 4 mg/mL BSA. Day 5 and Day 6 blastocysts (manipulation day was Day 0) were vitrified by equilibration with 25 mM HEPES-buffered TCM-199 containing 10% ethylene glycol, 10% DMSO, and 20% fetal calf serum for 2 min, followed by exposure to 20% ethylene glycol and 20% DMSO. Embryos were loaded into an OPS straw and immediately plunged into liquid nitrogen. The process from exposure of embryos to vitrification solution to plunging was 25–30 s. Embryos were thawed by immersing the end of the OPS straw in 0.3 M sucrose in which embryos were kept for 5 min, and then in 0.2 M sucrose for 5 min. Some embryos were cultured in PZM-3 for 12 h to determine the percentage and cell number of re-expanded blastocysts. The others were transferred to the uterus of a surrogate gilt within 3 h of thawing. Lipid removal appeared to have no harmful effect on embryo development and cell number of the blastocysts. Interestingly, a higher blastocyst percentage (28.8%, 178/619) was obtained with NT embryos from which the lipid had been removed as compared to normal NT (19.6%, 44/225; P < 0.01). The cell number (31.2 ± 7.7) of re-expanded blastocysts in the delipation group was comparable with normal NT blastocysts (33.6 ± 14.1, P = 0.33). The survival rate of blastocysts after freezing and thawing was enhanced after delipation (delipation group: 66.7%, 14/21; normal NT group: 21.9%, 9/42; P < 0.01). Two hundred and fourteen delipatized NT blastocysts were transferred to four surrogates after freezing and thawing. Three of the surrogates showed a delayed estrus cycle and one is still pregnant as confirmed by ultrasound scanning. We show that the combination of the OPS vitrification method with removal of lipid drops of oocyte cytoplasm might be an efficient way to cryopreserve porcine NT blastocysts. Funding for this project was from the NIH HL51670 and RR018877 and Food for the 21st Century.

318EFFECT OF PIG FOLLICLE FLUID AND FETAL CALF SERUM ON PORCINE OOCYTE MATURATION AND SUBSEQUENT DEVELOPMENT AFTER ACTIVATION AND SOMATIC CELL NUCLEAR TRANSFER

In vitro maturation of porcine oocytes is very important for understanding porcine somatic cell nuclear transfer (SCNT). In order to develop an in vitro maturation system that can provide more high quality oocytes, the effect of porcine follicle fluid (pFF) (gathered from 3–5-mm porcine follicles) and fetal calf serum (FCS: Sigma, St. Louis, MO, USA), as an important additional component of a chemically-defined medium was studied. Cumulus-oocyte complexes (COC) derived from follicles 3–5mm in diameter were cultured in three different media: a chemically-defined medium (CDM: TCM-199 with 0.1mgmL−1 cysteine, 10ngmL−1 EGF, 0.5μgmL−1 LH and 0.5μgmL−1 FSH); CDM with 10% pFF (CDM+p); and CDM with 10% FCS (CDM+F). After 42–44h of maturation, oocytes with a clear polar body were classified as matured oocytes. Matured oocytes stimulated by electric pulse (120v, 30μs, 2 pulse), or enucleated and fused with fibroblasts to construct SCNT embryos by using the same electrical parameters. All of these parthenogenetic and SCNT embryos were cultured in Porcine Zygote Medium-3. The blastocyst rate was assessed under a stereomicroscope on Day 6, and the number of nuclei in the blastocysts was counted under a fluorescent microscope after staining with 5μgmL−1 of Hoechst 33342. All data were subjected to a Generalized Linear Model Procedure (PROC-GLM) of Statistical Analysis System (SAS). The maturation rates of porcine oocytes in CDM and CDM+p were 53.2±3.8% (539/1050) and 69.7±3.8% (587/847), respectively;; in CDM and CDM+F, 61.1±3.1% (471/776) and 70.2±3.7% (577/844), respectively. Oocytes matured in CDM+p and CDM+F showed a higher (P&lt;0.05) maturation rate than those in CDM. The percentages of parthenogenetic blastocysts of oocytes matured in CDM and CDM+p were 13.9±2.1% (35/250) and 20.2±5.3% (64/300), and the numbers of nuclei in these blastocysts were 25.8±2.3 and 25.8±1.4, respectively. The blastocyst rate from CDM- and CDM+F-matured oocytes were 20.1±2.0% (53/272) and 22.2±4.7%(71/298), and the numbers of nuclei in these blastocysts were 24.7±1.5 and 25.3±1.5, respectively. There were no significant (P&gt;0.05) differences in the percentages of parthenogenetic blastocysts and nuclei numbers between CDM and CDM+p, or CDM and CDM+F. The percentages of blastocysts in SCNT embryos derived from CDM and CDM+p were 8.1±1.5% (14/192) and 12.3±1.9% (24/192), while the nuclei numbers in these blastocysts were 26.6±1.2 and 34.5±2.2, respectively. The percentages of blastocysts after SCNT from oocytes matured in CDM and CDM+F were 24.3±4.9% (35/139) and 27.1±5.5% (45/176), while the numbers of nuclei were 29.8±2.5 and 32.2±1.9, respectively. There were no significant (P&gt;0.05) differences between CDM and CDM+p, or CDM and CDM+F in SCNT embryo blastocyst rate, but the SCNT embryos derived from CDM+p showed a higher (P&lt;0.05) nuclear number. In conclusion, these results indicate that 10% pFF or FCS in CDM can promote a higher maturation rate of porcine oocytes. As recipient cytoplasm for SCNT, oocytes matured in CDM+p can support development of blastocysts that contain more nuclei than those matured in CDM alone. Supported in part by Food for the 21st Century and RR13438.

Reversal of severe late left ventricular failure after pediatric heart transplantation and possible role of plasmapheresis

Late acute cardiac graft failure carries a high mortality in adults. Vascular mediators and factors other than classic T-cell-mediated rejection may play a role in this process, and aggressive multimodality therapy may improve survival. We report experience with plasmapheresis in treating late severe acute left ventricular dysfunction in a group of pediatric heart transplant recipients. We retrospectively reviewed clinical records, echocardiograms, hemodynamics, coronary angiograms, biopsy specimens, and treatment regimens for 5 patients with 7 episodes of late-onset severe graft failure who recovered. Plasmapheresis was applied in all cases, in addition to methylprednisolone, cyclophosphamide, lympholytic agents, and aggressive supportive care including mechanical ventilation and hemofiltration. All patients presented with acute severe left ventricular dysfunction 1.4 to 7.9 years (mean 3.6) after orthotopic heart transplantation. Mean shortening fraction at presentation was 13 to 23% (mean 16), initial endomyocardial biopsy specimens were grade 0 to 3B, and immunofluorescence studies were negative. Treatment included plasmapheresis, cyclophosphamide, mechanical ventilation, hemofiltration, and inotropes. Clinical recovery was slow, with 4 to 8 weeks until left ventricular function normalized, and 2.2 to 9.4 (mean 4.6) weeks to hospital discharge. At follow-up (50 to 38 months, mean 24), all are alive. Two patients are well, whereas coronary vasculopathy developed in 3. Thus, survival may improve in patients with late graft failure with low biopsy score and plasmapheresis combined with multimodality therapy.

Effects of long-term infusion of prostacyclin on exercise performance in patients with primary pulmonary hypertension

STUDY OBJECTIVES

To determine whether long-term IV prostacyclin (PGI(2)) use improves exercise capacity in patients with primary pulmonary hypertension (PPH).

DESIGN

Cycle ergometry and the 6-min walk was used to evaluate the exercise performance of patients with PPH. The patients underwent serial exercise testing after starting continuous IV PGI(2) and were followed up for 19.5 +/- 7.5 months. Peak work, peak oxygen consumption (f1.gif" BORDER="0">O(2)), peak O(2) pulse, and distance walked in 6 min were used to evaluate performance.

BACKGROUND

PPH is characterized by medial hypertrophy and intimal proliferation of the pulmonary arterioles, leading to elevation of pulmonary artery pressure, right ventricular failure, and death. Palliative treatment consists of vasodilators, anticoagulants, cardiac glycosides, diuretics, and transplantation. PGI(2), a potent vasodilator and inhibitor of platelet aggregation, has been used for long-term treatment when conventional therapy has been unsuccessful.

PATIENTS

Sixteen patients with PPH (10 women, 6 men; mean age, 24 years).

RESULTS

At the initiation of PGI(2), peak work (+/- SD) was 35.5 +/- 11% of predicted; peak f1.gif" BORDER="0">O(2), 39 +/- 10.4%; peak O(2) pulse, 5.0 +/- 1.7 mL/min; and distance on the 6-min walk, 428 +/- 78 feet. At 18 to 27 months, peak work increased to 58.8 +/- 23% of predicted (p = 0.001), peak f1.gif" BORDER="0">O(2) increased to 52 +/- 15% of predicted (p = 0. 02), peak O(2) pulse increased to 7.1 +/- 3.0 mL/beat (p = 0.004), and performance on the 6-min walk increased to 526 +/- 62 feet (p = 0.001). There was a positive correlation between peak f1.gif" BORDER="0">O(2) and peak 6-min walk of 0.6 (p < 0.005) and between peak work and peak 6-min walk of 0.6 (p < 0.005).

CONCLUSIONS

Exercise capacity improved in our patients at up to 27 months of follow-up. Exercise testing is helpful in assessing the functional capacity of patients with PPH and may be useful in guiding therapy. Patients who deteriorate while receiving optimal conventional therapy should be considered for IV PGI(2) therapy.

Instilling a mediation-based conflict resolution culture

Conflict thrives and grows in the increasingly competitive and uncertain health care environment. Conflict impacts health care organizations' performance in several areas: (1) patient grievances and health plan member disputes; (2) internal employee and management disputes; and (3) payer, provider, and vendor disputes. "Grief Budgets," the hard costs and soft costs due to disputes that are poorly handled and conflicts that are ignored, detract from an organizations health mission and erode its bottom line. This article offers a strategy to solve conflict at an early stage in all three areas, with measurable results that strengthen profits and improve customer service by instilling a mediation-based conflict resolution culture throughout the organization. Mediation is non-adversarial, neutral, proactive, and collaborative. It is also confidential and always protects the future relationship between the parties. The challenge, therefore, is to strategically implant mediation into the health care organization's structure, to intercept and solve conflict early on. The article provides an overview of the steps needed to install a dispute resolution program.

Experimental branch pulmonary artery stenosis angioplasty using a novel cutting balloon

To determined the safety and efficacy of a bladed balloon in the treatment of branch pulmonary artery stenosis, a model of left pulmonary artery stenosis was surgically created in two-week-old pigs. Seven pigs underwent angioplasty, five with the bladed balloon and two with conventional balloons. Overall, acute results showed a fall in the peak systolic pressure gradients from 8.3 +/- 2.3 mmHg to 3.2 +/- 3.1 mmHg and an increase in the minimum stenotic diameters from 4.5 +/- 2mm to 5.6 +/- mm. Acute pathological examination after cutting angioplasty showed regular luminal cuts that healed completely by four to six weeks in chronically surviving animals. Two of three surviving animals had persistent vessel enlargement at follow-up with one showing little overall change. Cutting balloons are effective in branch pulmonary artery angioplasty and may have clinical applications.

Balloon dilation of severe aortic stenosis in the neonate: comparison of anterograde and retrograde catheter approaches

OBJECTIVES

We sought to compare anterograde and retrograde balloon dilation of severe aortic valve stenosis in neonates.

BACKGROUND

There is a high incidence of iliofemoral artery complications after retrograde balloon dilation of the aortic valve in the neonate. Therefore, a nonarterial technique of catheter access to the aortic valve would be worth exploring.

METHODS

Group 1 included 11 consecutive patients (median age 6 days, range 1 to 42; median weight 3.5 kg, range 2.16 to 4.25) undergoing attempted anterograde dilation through a femoral venous approach. Group 2 included 15 patients (median age 3 days, range 1 to 35; median weight 3.4 kg, range 2.5 to 4.4 kg) who underwent attempted retrograde dilation, including 2 in whom attempted anterograde approach had failed.

RESULTS

The valve was successfully crossed in 9 of 11 anterograde and 13 of 15 retrograde dilations. In both groups, the peak gradient across the valve decreased significantly (both p = 0.001). On echocardiography, the jet width of the aortic incompetence/ annulus diameter ratio was 0.16 +/- 0.08 (mean +/- SD) after anterograde and 0.51 +/- 0.24 after retrograde dilation (p = 0.03), possibly because of unrecognized valve leaflet perforation. Two patients in group 1 developed persistent, mild mitral insufficiency. Femoral artery thrombosis developed in one patient after anterograde dilation and in eight after retrograde dilation (p = 0.03).

CONCLUSIONS

This series demonstrates that an anterograde approach for balloon angioplasty of severe neonatal aortic valve stenosis is feasible, achieves good hemodynamic relief and lessens morbidity compared with retrograde arterial techniques.