Subcutaneous Vascular Access Ports Research Articles

Subcutaneous vascular access port implantation in the axillary or femoral/external iliac vein at the time of full limb amputation in dogs.

To report outcomes and complications after placement of a subcutaneous vascular access port (SVAP) in the jugular (jSVAP), axillary (aSVAP), and femoral or external iliac vein (fSVAP) in dogs. Retrospective. Medical records from a single hospital, covering a period between September 2015 and October 2020, were reviewed to identify dogs that had an SVAP placed. Complications and outcomes for dogs who had an SVAP placed in the axillary vein, or femoral/external iliac vein during amputation for appendicular skeletal neoplasm, and in the external jugular vein were recorded and analyzed statistically. Subcutaneous vascular access ports were placed in the axillary vein in 13 dogs, femoral/external veins in 4 dogs, and in the jugular vein in 19 dogs. The SVAPs fulfilled their purpose throughout treatment in 12/13 aSVAP, 4/4 fSVAP, and 15/19 jSVAP. Dogs were followed for a median of 145.5 days (range 30-945 days). Minor and major complications were recorded in 1/13 and 2/13 aSVAPs, 0/4 and 0/4 fSVAPs, and 3/19 and 4/19 of jSVAPs. Two dogs with jSVAPs were euthanized due to SVAP-related complications. No difference in complication rate was detected between groups (P=.12). No difference in short-term outcome was detected between implantation sites for subcutaneous vascular access ports. The axillary or femoral/external iliac veins offer alternative sites for placement of SVAP in dogs undergoing limb amputation.

Empyema Thoracis Due to Intrapleural Migration of Retained Vascular Catheter

Intravascular retention and embolization of fragment of central venous catheters is a rare but well-documented complication of in-dwelling vascular access devices and ports. We describe the case of a 39-year-old male with fracture of the central venous catheter during removal of subcutaneous vascular access port. Over the next 3 years, the catheter fragment embolized through the pulmonary circulation and subsequently migrated into the left pleural space. He presented with empyema thoracis associated with thoracolumbar vertebral osteomyelitis. He required video-assisted thoracoscopy for retrieval of the catheter fragment, left lung decortication, and subsequent multilevel vertebral corpectomy and spine stabilization procedures.

Complications associated with use of subcutaneous vascular access ports in cats and dogs undergoing fractionated radiotherapy: 172 cases (1996–2007)

To describe complications associated with use of a subcutaneous vascular access port (SVAP) in cats and dogs treated with fractionated radiotherapy and to determine predisposing factors for developing these complications. Retrospective case series. 46 cats and 126 dogs. The medical records of cats and dogs undergoing radiation therapy that received placement of an SVAP between March 1996 and August 2007 were reviewed. Data were recorded and analyzed to determine factors for development of complications associated with the use of an SVAP during treatment with fractionated radiotherapy. 18 and 36 major and minor complications were identified, respectively. Sex and the lack of administration of propofol during anesthesia induction were significantly associated with development of major complications. Female cats and dogs were 5.00 times as likely as male cats and dogs to develop major complications associated with SVAP usage. Animals in which propofol was not administered were 19.15 times as likely as animals administered propofol to develop major complications. Placement of SVAP catheters in a femoral vein was 17.20 times as likely as placement in the jugular vein to result in minor complications. Factors associated with the development of complications included sex, propofol administration, and vein in which an SVAP catheter was inserted. The use of an SVAP may be a useful alternative to repeated catheterizations in cats and dogs.

Long‐term pericardial catheterization is associated with minimum foreign‐body response

The goals of this study were to assess the feasibility and to characterize the foreign-body response of a long-term catheter in the pericardium. Long-term access to the normal pericardial space provides opportunities for diagnostic sampling and therapeutic intervention. After thoracotomy, in 7 anesthetized canines, the pericardium was opened and a 5 French silicone vascular access catheter was advanced 10 cm into the pericardial sac toward the apex of the heart. A hydraulic coronary balloon occluder was implanted (N=6). Pericardium was sealed with Prolene suture. Catheters were tunneled to the nape of the neck, attached to a subcutaneous vascular access port, and buried in the fascia. Animals underwent multiple experimental coronary artery occlusions across months. At sacrifice, we assessed the histopathological response of pericardium and epicardium to chronically indwelling silicone catheters. Post-mortem examinations were performed at 213 days post-operatively (mean, range=96-413, N=6), with one animal maintained for longer-term study. At sacrifice, all catheters were bidirectionally patent and completely mobile in the pericardium without evidence of tissue overgrowth around the intrapericardial segment. Adhesion tissue was found only at the site of catheter entry through the pericardium. Microscopic histopathological examination at catheter entry site, surrounding pericardium, and myocardium revealed minimum chronic inflammation. This subcutaneous system provides dependable, chronic access to the normal pericardial space for drug delivery and sampling. The presence of a chronic silicone catheter in the pericardium does not precipitate clinically significant pathologic changes even after repeated ischemic events.

Repeat Microsphere Delivery for Serial Measurement of Regional Blood Perfusion in the Chronically Instrumented, Conscious Canine

For chronic, repeat hemodynamic studies in conscious dogs, we designed and tested a chronically instrumented canine microsphere delivery model. The goals of this study were (1) to investigate the accuracy of repeated estimations of blood perfusion using fluorescent-labeled microspheres and (2) to develop and validate a chronic preparation that permits consecutive estimations in the same conscious animal over an extended protocol. Via thoracotomy, nine dogs were instrumented with left atrial appendage and aortic vascular access catheters connected to subcutaneous vascular access ports. Four animals received seven serial injections of 1.6 million 15 microm microspheres (total: 11.2 million), and five animals received 8 serial injections of 2.25 million microspheres (total: 18 million) over the course of 11 or 18 wk. All catheters have remained bidirectionally patent during protocol for 14.9 +/- 0.8 (mean +/- SEM) wk. Sphere accumulation did not significantly alter global myocardial (P = 0.69, P = 0.25), renal (P = 0.92, P = 0.12), hepatic (P = 0.84, P = 0.32), or splenic (P = 0.33, P = 0.70) blood perfusion in either set of animals. Catheters remained bidirectionally patent for months, did not interfere with the hemodynamic responses of the preparation, and allowed repeat percutaneous injection of microspheres and withdrawal of reference arterial blood from within conscious canines. Eight serial injections totaling 18 million microspheres over 18 weeks did not alter regional myocardial, hepatic, renal, or splenic blood flow. This dependable, chronic, percutaneous arterial access preparation provides a means for examining acute and long-term effects of pathophysiological, pharmaceutical, and environmental influences on regional arterial blood flow in conscious, large animals.

Use of vascular access ports with intrathoracic drains for treatment of pleural effusion in three dogs

3 dogs (9 to 12 years old) were evaluated because of recurrent pleural effusion that was refractory to treatment of the underlying cause. Dogs were evaluated because of cough, dyspnea, tachypnea, or lethargy or a combination of these clinical signs. Radiography, ultrasonography, or thoracocentesis were used to confirm the presence of pleural fluid in each dog. A neoplastic cause of pleural effusion was confirmed in 2 dogs. In 1 dog, fasciitis of the mediastinum and the left parietal pleura was diagnosed, with no evidence of neoplasia. Each dog was anesthestized, and thoracotomy was performed with manual perforation of the mediastinum. Permanent, subcutaneously placed vascular access ports were attached to intrathoracic, Jackson-Pratt drain tubing for repeated drainage of pleural fluid. Drains were used successfully in the 3 dogs for periods of 6 weeks, 11 weeks, and > 3 years. Findings suggest that subcutaneous vascular access ports attached to intrathoracic drain tubing may be an effective way to remove recurrent pleural effusion in dogs.

Technique for Implantation of Chronic Indwelling Aortic Access Catheters

Introduction For chronic, repeated cardiovascular studies in trained, conscious dogs, we describe a technique for implantation of an arterial vascular access catheter in the aorta. In comparison to previous techniques, our technique enables arterial catheter implantation without interrupting the systemic circulation or compromising peripheral arterial flow, requires only a single penetration of the aortic wall, and results in a catheter facing downstream in the aorta. The catheter is usable for both arterial blood sampling and intra-arterial injection of pharmacologic agents.Methods After thoracotomy, two purse-string sutures were set in the aortic wall at the catheter entry-site. A Debakey–Satinsky vena cava clamp was used to partially clamp and isolate a 3-cm portion of aorta surrounding the pursestring sutures. The catheter was prepared by inserting a 0.35 mm guide wire, curve tip end first, into a 7 French silicone Access Technologies catheter. This caused a slight bend at the tip of the catheter, which later facilitated entry into the aorta and prevented damage to the intima of the aortic wall. Catheters were tunneled from the thorax to the nape of the neck, attached to a subcutaneous vascular access port (VAP), and buried in the fascia. Catheters were locked with 2 mL heparinized saline (20 IU/mL). With this technique, we implanted 16 aortic vascular access catheters in 16 dogs.Results Of the 16 animals, 8 are being maintained for long-term study, 7 were sacrificed for histopathological examination, and 1 died due to improper catheter implantation without the aid of the curved-tip guide-wire technique. VAPs have remained bidirectionally patent in all long-term animals (n = 8) ongoing for 7.5 ± 1.4 months (mean ± SEM), with an ongoing maximum of 14 months. In these long-term animals, VAPs were used 5.88 ± 1.34 times. Postmortem examinations were performed on short-term animals (n = 8) sacrificed at 2.85 ± 1.29 months. The catheters have remained bidirectionally patent in all but the one animal that died. In the short-term animals, the 7 patent VAPs were used 12.71 ± 1.64 times. Histopathological examination of hematoxylin and eosin (H&E) slides from the catheter entry site revealed only minimal chronic inflammation. No evidence of tissue overgrowth around any of the intravascular segments of these silicone catheters was noted in any animal.Conclusions Thus, this dependable subcutaneous arterial access system provides a means for examining acute and long-term effects of environmental and pathophysiological influences in conscious dogs. These catheters have remained bidirectionally patent ongoing for more than 1 year and allowed infusion of agents and withdrawal of central arterial blood samples.

Long‐Term Totally Implantable Venous Access Ports in Dogs and Cats Receiving Chemotherapy

Introduction: We evaluated the totally implantable subcutaneous vascular access port (VAP) in 16 cancer patients undergoing intermittent chemotherapy for more than 30 months.Methods: Ports were surgically placed (The CompanionPort, Norfolk Vet Products, Skokie, Illinois 60076) in the jugular vein of 12 dogs and 4 cats between 1/2002 and 7/2004. Body weight determined polyurethane catheter size (4, 5, 7 fr.). The polysulfone port, surrounded by titanium, was anchored to subcutaneous tissue in the dorsolateral neck and confirmed with C‐arm fluoroscopy. All blood samples were obtained via VAP. Nine anticancer agents, other medications, crystalloids/colloids, and whole blood were administered. Ports were flushed every 4–5 weeks with heparinized saline solution (100 IU/ml). Removed catheters were submitted for bacteriology.Results: Seven of 16 animals are still alive. VAP were used for 1.5 to more than 30 months with 4–60 injections/port. Catheter tips were visualized from the left atrium distally into the caudal vena cava. Adverse events included post‐operative subcutaneous bruising and/or hematoma (4/16), difficult aspiration (4/16), catheter malposition (1/16), positional flushing (1/16), and occlusion requiring replacement (1/16). No thrombus formation or extravasation was evident. Bacterial colonization without signs of septicemia was observed in 3/4 catheters.Conclusions: VAP are an effective way of achieving long‐term venous access in the dog and cat. Complications are typically minor and infrequent.

The influence of route of administration on the acute cardiovascular effects of cocaine in conscious unrestrained pregnant rats

The intravenous route of administration, accessed via a subcutaneous vascular access port, has been recently suggested as an animal model for studying the developmental effects of maternal cocaine abuse in the pregnant and/or group-housed rat. The present study (1) assessed the cardiovascular effects of intravenous (IV) cocaine, delivered via bolus injection, in chronically catheterized near-term pregnant rats, and (2) compared the IV cardiovascular responses to those following cocaine delivered via the commonly employed subcutaneous (SC) and intragastric (IG) routes of administration. Pregnant gestation day 15 (GD15) young adult female Sprague–Dawley rats ( n = 21) were anesthetized and catheters surgically implanted into the carotid artery, jugular vein, fundus of the stomach, and a subcutaneous pouch. On GD17–19, heart rate (HR) and mean arterial pressure (MAP) were assessed, using a within-subjects design, prior and subsequent to IV (3 mg/kg), IG (60 mg/kg), and SC (40 mg/kg) cocaine. An interval of 6 h separated IV and IG cocaine administration and an interval of 18 h separated IG and SC cocaine administration. The peak responses of HR (23%↓) and MAP (37%↑) following IV cocaine were noted within 0.5 min. In contrast, the peak responses of HR (4%↓, 6%↓) and MAP (2%↑, 15%↓) after IG (23 min) or SC (26 min) cocaine, respectively, were significantly smaller and markedly delayed. No significant change in aortic blood flow velocity was detected following cocaine via any route of administration, although phasic flow velocities (PFV) were differentially sensitive to route of administration (PFV dias not PFV sys); IV cocaine increased (55%↑) whereas IG or SC cocaine decreased ∼35%↓) PFV dias. The pressor effects of an equimolar dose of IV cocaine methiodide (3.9 mg/kg) were indistinguishable from those of IV cocaine (38%↑ vs. 37%↑), as were the effects on PFV dias (83%↑ vs. 55%↑). The lack of an effect of cocaine methiodide on HR was consistent with the bradycardia effect of cocaine attributable to central mediation of the baroreflex. Finally, the pressor effects of IV cocaine paralleled the rapidly peaking arterial plasma levels of cocaine noted within 30 s after the initiation of drug injection. In sum, prominent effects of IV cocaine on maternal cardiovascular physiology are noted; as such, the recent reports of a lack of maternal/fetal toxicity following daily (3–6mg/kg) IV cocaine during GD8–21 are not due to use of an ineffective drug dose. It was equally clear that the SC and IG routes of exposure did not reproduce the cardiovascular component(s) of the expected physiological response to cocaine.

Acquisition of intravenous cocaine self-administration with concurrent access to food in cynomolgus monkeys.

The present study used a concurrent schedule of food and drug delivery in socially housed male cynomolgus monkeys (Macacafascicularis; N = 15) to study variables that influence cocaine acquisition. Each monkey was implanted with subcutaneous vascular access ports, and responding was maintained under a concurrent food, saline schedule with the lever associated with each stimulus presentation varied daily. Next, increasing cocaine doses (0.003-0.3 mg/kg/inj) were concurrently available with food for at least 5 consecutive sessions per dose. Under these conditions, an unexpected lever bias emerged in all 15 monkeys. The development of the lever bias could not be predicted on the basis of cocaine dose or total intake and was not related to social rank. These findings suggest that in monkeys, concurrent fixed-ratio schedules of food and cocaine presentation may result in persistent biased responding that overshadows cocaine preference in studies of acquisition.

Induction, maintenance, and reversal of streptozotocin-induced insulin-dependent diabetes mellitus in the juvenile cynomolgus monkey (Macaca fascilularis).

Insulin-dependent diabetes mellitus (IDDM) is the second most prevalent chronic illness of children. Investigation of the treatment of IDDM is hindered by the lack of a reproducible and easily maintained non-human primate model of this disorder. We induced IDDM in 11 juvenile cynomolgus monkeys after a single (150 mg/kg) intravenous injection of streptozotocin (STZ). All diabetic monkeys were treated with insulin twice daily, based on a sliding scale. Subcutaneous vascular access ports were surgically placed in each monkey to facilitate serial blood sampling and drug administration. Allogeneic pancreatic islet cells from unrelated donors were subsequently transplanted into the mesenteric circulation of all STZ-treated monkeys. Mild, transient nausea and vomiting occurred in all animals after STZ injection; however, no additional signs of toxicity occurred. Within 36 hr, all monkeys required twice daily administration of exogenous insulin to maintain a non-ketotic state. Serum C-peptide levels decreased from >1.2 ng/ml before STZ, to between 0.0 and 0.9 ng/ml after STZ, confirming islet cell destruction. Animals were maintained in an insulin-dependent state for up to 147 days without any observable clinical complications. Subcutaneous vascular access port patency was maintained up to 136 days with a single incidence of local infection. Islet cell transplantation resulted in normoglycemia within 24 hr. Serum C-peptide levels increased (range: 2-8 ng/ml) for 6 - 8 days in immune competent animals, and for 39-98 days after transplant in immunosuppressed monkeys. IDDM can be consistently induced and safely treated in juvenile cynomolgus monkeys. Chronic vascular access can be maintained with minimal supervision and complications. This model is appropriate for studies investigating potential treatments for IDDM including islet cell transplantation.