Mechanical disruption of pulmonary emboli in dogs with a flexible rotating-tip catheter (Kensey catheter).

Pulmonary embolism was induced in 11 dogs by the injection of three- to four-day-old allogeneic blood clots. The clots were made radiopaque by soaking them in contrast material. The resulting clots were firm, 3 to 4 cm long, and 1 cm in diameter. Injection of the clots into the external jugular vein consistently produced occlusion of at least one of the lobar pulmonary arteries. In every instance in which the tip of the catheter could be positioned at the clot embolus (six dogs), the clots were readily fragmented with a number 8 French (2.67 mm OD) flexible rotating tip catheter (Kensey catheter) activated at 80,000 rpm. Overall perfusion was shown by posttreatment angiograms to be markedly improved. These studies show that catheter-tip fragmentation of pulmonary emboli with a Kensey catheter has excellent potential for therapeutic application in patients with pulmonary embolism.

Percutaneous gallstone lithotripsy. Results in acute and chronic swine models.

The authors describe here a rotary catheter for the percutaneous fragmentation of gallstones. Gallstones are drawn into the rotating impeller by a powerful vortex and mechanically fragmented. Fragments are aspirated from the gallbladder following use of the device. The safety and efficacy of the device was tested after placement of human gallstones in the pig's gallbladder in 19 acute, 15 chronic, and two control experiments. In 27 completed experiments, 206 human gallstones (6-20 mm) were implanted. Most residual fragments were less than 2 mm; 24 fragments were 2 to 4 mm and seven were 5 to 8 mm. Acute histologic changes included focal loss of mucosa, mucosal and submucosal hemorrhage, and deposition of biliary material in the mucosa and submucosa. At 30 and 90 days, gallbladder histology revealed regeneration of the mucosa with isolated granuloma formation.

Puncture site hemostasis.

The Angio-Seal hemostatic puncture closure device was designed to provide diagnostic as well as post-complex angioplasty hemostasis in coronary and peripheral procedures without compromising blood flow to the distal extremity: 1) by allowing immediate removal of the introducer sheath, and 2) by providing puncture hemostasis without the need for manual pressure. The Angio-Seal is currently in clinical trials and is being evaluated by the FDA. We are hopeful that its future use will reduce the cost of medicine while greatly enhancing the quality of patient care as initial clinical trial results indicate.

Effects of the non-Newtonian viscosity of blood on flows in a diseased arterial vessel. Part 1: Steady flows.

Effects of the non-Newtonian viscosity of blood on a flow in a coronary arterial casting of man were studied numerically using a finite element method. Various constitutive models were examined to model the non-Newtonian viscosity of blood and their model constants were summarized. A method to incorporate the non-Newtonian viscosity of blood was introduced so that the viscosity could be calculated locally. The pressure drop, wall shear stress and velocity profiles for the case of blood viscosity were compared for the case of Newtonian viscosity (0.0345 poise). The effect of the non-Newtonian viscosity of blood on the overall pressure drop across the arterial casting was found to be significant at a flow of the Reynolds number of 100 or less. Also in the region of flow separation or recirculation, the non-Newtonian viscosity of blood yields larger wall shear stress than the Newtonian case. The origin of the non-Newtonian viscosity of blood was discussed in relation to the viscoelasticity and yield stress of blood.

Experimental percutaneous gallstone lithotripsy: results in swine.

The Kensey-Nash device is used to fragment gallstones percutaneously. It is inserted into the gallbladder through an 8-F introducer sheath, a cage is expanded to protect the gallbladder, and the impeller is activated. A strong vortex automatically pulls the stones into the basket. The device was tested in 24 pigs in which human gallstones (5-19 mm, bilirubin and cholesterol types) had been implanted and in two control pigs with no gallstones. All pigs except two were killed immediately after the procedure (acute studies); the two were followed up for 36 days and then killed. Fragments (1-3 mm) were similar in size to those seen in current extracorporeal shock wave lithotripsy studies. A complication occurred in one animal, and technical failures occurred in two, causing these three studies to be aborted.

Recanalization of obstructed arteries with a flexible, rotating tip catheter.

A flexible, rotating tip catheter (Kensey catheter) was used to recanalize 24 segments of diseased superficial femoral arteries (from cadavers) that were sewn as xenografts into the femoral, carotid, or aorticorenal arteries of 14 dogs. One perforation occurred; there were emboli in some brains and kidneys, the consequences of which remain unknown. No signs of gross neurologic deficits or limb ischemia were seen at 0-11 days.

Percutaneous rotational contact biliary lithotripsy: initial clinical results with the Kensey Nash lithotrite.

The percutaneous rotary lithotrite introduces a new concept to fragmentation and percutaneous removal of gallstones. A fluid vortex is generated, pulling calculi into a high-speed blade that fragments stones to predominantly under 500 microns. The results of treating the first 10 patients with this instrument reveal that large stone burdens as well as small stones (2-3 mm) of any composition can be removed if the gallbladder is of sufficient size to accommodate the six-pronged basket. Rotation times of 7-39 minutes were required. Nine of 10 procedures were completed; access was lost in one case. One major complication occurred. At repeat oral cholecystography, the gallbladder was visualized after 3-6 weeks in eight of the nine patients. Ursodeoxycholic acid was administered from 3 to 12 months to five patients with either residual stones or aggregates. The hospital stay ranged from 48 to 72 hours. All patients (except the patient who underwent surgery) resumed light activity in 3-4 days and strenuous activity and full diet within 3 weeks.

Immediate arterial hemostasis after cardiac catheterization: initial experience with a new puncture closure device.

A novel device for obtaining arterial hemostasis after invasive procedures was tested in 30 patients undergoing diagnostic catheterization (26 patients) or coronary angioplasty (4 patients). The device is deployed through an arterial sheath and forms a positive mechanical seal both inside and outside the defect in the arterial wall. The components are all bioabsorbable. Thirteen patients received a heparin bolus during the catheterization procedure. The activated clotting time recorded in 15 patients just prior to device deployment averaged 264 sec. 29 of 32 attempted device deployments were successful (91%); and the remaining 3 devices pulled completely out as called for by design in the event of incomplete deployment. Twenty-nine patients ultimately achieved successful hemostasis using the device, with the other patient receiving manual hemostasis. Of these 29, hemostasis was immediate and complete in 19 patients. Light digital pressure was required in another 8 patients for less than 5 min. There was minor delayed bleeding requiring supplemental light pressure in several cases. A total of 11 patients required supplemental pressure in addition to the hemostasis device. The use of bolus heparin was significantly (P = 0.05, Fisher's exact test) related to the requirement for supplemental pressure. Three patients developed hematomas, one of which was present prior to device deployment. The other two patients had received bolus heparin. No patient required transfusion or surgical repair. There was no change in the ankle/brachial systolic blood pressure index after device deployment or at late (30-60 day) follow-up. Ultrasound studies revealed no significant pathology relative to the device.(ABSTRACT TRUNCATED AT 250 WORDS)