Validation of US-guided percutaneous venous access and manual compression for studies in swine

Minimally invasive ultrasound-guided technique for central venous catheterization via the external jugular vein in pigs

OBJECTIVE

To describe an ultrasound-guided technique for central venous catheter placement via the external jugular vein (EJV) in pigs.

ANIMALS

96 healthy Landrace-Poland China barrows (approx 16 weeks old with a mean weight of 70 kg).

PROCEDURES

Pigs were anesthetized. With ultrasound guidance, a needle was inserted into the EJV without a large incision or cutdown procedure. A guidewire was inserted through the needle into the vein. A modified Seldinger technique was used to advance a catheter into the vessel until the tip was in the cranial vena cava near the right atrium. A trocar was used to create a tunnel through the subcutaneous tissues from the catheter insertion site to between the dorsal borders of the scapulae. The free end of the catheter was passed through that tunnel. An extension was attached to the catheter and secured to the skin. Pigs were euthanized and underwent necropsy at completion of the study for which they were catheterized.

RESULTS

Central venous catheters were successfully placed in all 96 pigs and facilitated collection of serial blood samples with minimal stress. Catheters remained in place for a mean of 6 days (range, 4 to 10 days). Necropsy revealed abscesses along the subcutaneous catheter tract in 9 pigs. Twenty pigs had histologic evidence of phlebitis and fibroplasia in the cranial vena cava.

CONCLUSIONS AND CLINICAL RELEVANCE

The described technique, in combination with extensive socialization, allowed serial collection of blood samples with minimal stress and restraint and is an alternative to surgical cutdown procedures for catheter placement.

Canine Model for Selective and Superselective Cerebral Intra-Arterial Therapy Testing

PURPOSE

With advancing endovascular technology and increasing interest in minimally invasive intra-arterial therapies such as stem cell and chemotherapy for cerebral disease, the establishment of a translational model with cerebral circulation accessible to microcatheters is needed. We report our experience catheterizing canine cerebral circulation with microcatheters, present high-resolution angiographic images of the canine vascular anatomy, describe arterial branch flow patterns and provide measurements of canine arterial conduits.

MATERIALS AND METHODS

Angiograms were performed on 10 intact purpose-bred hounds. Angiography, measurements of arterial conduits and catheterization information for intracranial arterial branches were obtained.

RESULTS

Selective and superselective cerebral angiography was successful in all subjects. Relevant arterial mean diameters include the femoral (4.64 mm), aorta (9.38 mm), external carotid (3.65 mm), internal carotid arteries (1.6 mm), vertebrobasilar system and Circle of Willis branches. Catheterization of the Circle of Willis was achieved via the posterior circulation in all subjects tested (n=3) and the use of flow directed microcatheters resulted in reduced arterial tree deformation and improved superselection of intracranial vessels. Catheterization of the intracranial circulation was attempted but not achieved via the internal carotid artery (n=7) due to its tortuosity and subsequent catheter related vasospasm.

CONCLUSION

The canine cerebral vasculature is posterior circulation dominant. Anterior circulation angiography is achievable via the internal carotid artery, but direct cerebral arterial access is best achieved via the posterior circulation using flow-directed microcatheters. It is feasible to deliver intra-arterial therapies to selective vascular territories within the canine cerebral circulation, thus making it a viable animal model for testing novel intra-arterial cerebral treatments.

Sonographically guided placement of intravenous catheters in minipigs

Many procedures in minipigs require establishment of reliable deep venous access with a large-bore catheter. In animal experiments, such catheters are typically implanted surgically. In clinical settings, however, ultrasound imaging is routinely used to facilitate safe, minimally invasive puncture of deep vessels. The authors describe a technique for using ultrasound guidance to puncture and cannulate the minipig femoral vein. They carried out the procedure in six minipigs for the purpose of injecting contrast agents for subsequent imaging scans. The procedure was ultimately successful in all pigs, took 10 min on average and resulted in no physiological complications. In one minipig, however, a 10-cm-long catheter became dislodged from the femoral vein; use of a longer (25-cm-long) catheter was optimal for establishing reliable intravenous access.

Transauricular Arterial or Venous Access for Cardiovascular Experimental Protocols in Animals

PURPOSE

To describe a safe percutaneous method of transauricular endovascular access in small and large animals that uses basic catheter-based interventional skills and renders surgery and general anesthesia with intubation unnecessary.

MATERIALS AND METHODS

Twenty New Zealand White rabbits and five domestic juvenile swine were used in the experiments. Animals were restrained in the supine position after induction of dissociative anesthesia. Transauricular endovascular access was accomplished by percutaneous catheterization of the auricular artery or vein, roadmap imaging, introduction of a 0.018-inch hydrophilic guide wire, and over-the-wire vascular sheath insertion after serial tract dilations.

RESULTS

Technical success rates were 90% and 100% for intraarterial and endovenous access in the rabbit, respectively, and 100% for both routes in the pig. The largest sheaths inserted were 5 F in the rabbits' aortae, 7 F in the rabbits' venae cavae, 6 F in the pigs' aortae, and 8 F in the pigs' venae cavae. Animal recovery was uneventful, and 48-hour necropsy detected only minor perivascular hematoma in cases of transauricular intraarterial access. Peripheral, intracoronary, intrapulmonary, and intracerebral selective vascular access was safe and feasible. A method of reserving the transauricular endovascular access for future interventions or follow-up by placement of indwelling hydrophilic catheters was also established.

CONCLUSIONS

Transauricular endovascular access is a successful technique for establishing and maintaining intraarterial or endovenous vascular access. It obviates surgical cutdown and sacrifice of the femoral and cervical vessels and might considerably improve and expedite cardiovascular experimental protocols in small and large animals.