Carol C. Coleman

Renal vascular complications associated with the percutaneous removal of renal calculi.

Significant immediate and delayed vascular complications occurred in 4 of 140 patients (3 per cent) undergoing percutaneous removal of renal and ureteral calculi. An understanding of renovascular anatomy, use of a safety guide wire and intraoperative availability of an angiographic balloon catheter may help to prevent and to treat bleeding problems.

Experimental Evaluation of a New Self-expanding Patent Ductus Arteriosus Occluder in a Canine Model

PURPOSE A new self-expanding patent ductus arteriosus (PDA) occluder was designed. MATERIALS AND METHODS Percutaneous closure of surgically created aortopulmonary shunts was attempted in 19 dogs. The occlusion device consisted of a nitinol wire frame tightly woven into a cylinder with a flat retention disc. A polyester-filled frame was used in the last six procedures. A 6-F introducing sheath was advanced across the aortopulmonary conduit into the descending thoracic aorta. The prosthesis (attached on a stiff delivery cable) was advanced through the introducing sheath. The retention disc was first released in the descending thoracic aorta, then the cylindrical device frame was expanded within the conduit by withdrawing the sheath. RESULTS Subtotal misplacement into the descending aorta occurred in one procedure (overall technical success rate, 95%), and one animal died before the 1-week follow-up. Complete angiographic shunt closure was achieved in seven of 18 (39%) animals at 30 minutes, 12 of 17 (71%) animals at 1 week, 14 of 17 (82%) animals at 1 month, and 11 of 12 (92%) animals at 3 months. Significantly higher 30-minute closure rates occurred with polyester-filled occluders compared with nonfilled occluders (five of five [100%] vs one of 13 [15%]; P = .002). Persistent shunt at 3 months occurred in only one nonfilled device (6%). In the remaining 16 animals, both orifices of the shunt were covered by a smooth glistening neoendothelium at postmortem examination. CONCLUSION This device combines the advantages of small delivery system, easy placement, self-centering, and repositionability. Immediate shunt closure can be reliably accomplished with the polyester-filled prosthesis.

Hemolytic Effect of the Amplatz Thrombectomy Device

PURPOSE The hemolytic effect of the Amplatz thrombectomy device (ATD) was evaluated in nine dogs and in nine patients. MATERIALS AND METHODS The device was activated for 1-2 minutes in the abdominal aorta, inferior vena cava, or femoral artery of nine dogs. The device was activated for 1-4 minutes in the nine patients in occluded lower extremity bypass grafts (n = 5), native superficial femoral artery (n = 1), a pulmonary artery embolus (n = 1), a portocaval shunt (n = 1), and an iliac vein stent (n = 1). Patients were examined for laboratory evidence of hemolysis following mechanical thrombectomy. RESULTS In all dogs haptoglobin level decreased, free hemoglobin level in the plasma increased, and hemoglobinuria was present. There was no change in renal function. The level of haptoglobin decreased and the level of plasma free hemoglobin increased in eight patients, with hemoglobinuria detected in one. More hemolysis was observed in the animals than in the patients. CONCLUSION The ATD has a definite transient hemolytic effect. Until further studied, it should not be used in children and should be used with caution in patients who are anemic, hypoxemic, or have potentially reversible renal insufficiency. Activation time should be monitored closely because hemolysis probably increases with increasing activation time.

Percutaneous removal of caliceal and other "inaccessible" stones: instruments and techniques.

Percutaneous removal of renal stones is becoming an established procedure, especially for stones lying free in the renal pelvis. However, some renal stones, particularly caliceal stones, are less accessible and require special techniques for removal. We discuss these techniques, which include 1) retrograde pyelography to facilitate a thorough understanding of caliceal anatomy and stone position in 3 dimensions, 2) approaches for accurate placement of a nephrostomy tract for straight-line access to the stone(s), 3) judicious use of percutaneous punctures above the 12th rib and secondary percutaneous tracts, and 4) skilled choice and use of a large variety of cutting, extracting and disintegrating instruments with endoscopic and/or fluoroscopic control. The flexible nephroscope is valuable especially to reach inaccessible areas, although its skilled use requires experience. Flexible endoscopy often is aided by pressure irrigation, an assistant and simultaneous fluoroscopic control.

Percutaneous Removal of Caliceal and Other “Inaccessible” Stones: Results

Percutaneous removal of renal stones (percutaneous nephrolithotomy) is becoming an established procedure, especially for stones lying free in the renal pelvis. However, some renal stones, particularly caliceal stones, are less accessible and, therefore, more difficult by the percutaneous route. We removed percutaneously 95 caliceal or otherwise poorly accessible renal stones from 53 patients with a variety of techniques, including percutaneous puncture above the 12th rib, double or Y percutaneous nephrostomy tracts, rigid and flexible endoscopy, and intrarenal cutting with diathermy. Intravenously assisted local anesthesia was used exclusively in 89 per cent of the patients. Status free of stones was achieved in all but 1 patient who retained 2 small fragments. The average number of sessions was 1.89 and the average hospital stay was 7.9 days. Complications were minor except for 1 patient who required tertiary renal artery embolization for bleeding. Illustrative cases are presented. Virtually all renal stones can be removed percutaneously.

Registering Molecular Imaging Information into Anatomic Images with Improved Spatial Accuracy

To make molecular imaging useful in the clinic, accurate image registration must be done to correlate nano-scale events to macro-scale anatomy. The 3D volumetric image registration technique uses visual and quantitative measures to identify the most homogeneous color distribution on a volumetric anatomical landmark. Four phantom PET/CT images were acquired with 5.0 plusmn 0.1 mm shift interval. The image registration shift was compared with the positioning shift. An accuracy of 0.1deg and 0.1 mm was achieved. Cranial PET/CT images from 39 patients were examined. It was found that the average head motion was 0.5-1deg and 1-3 mm, even with a stringent head holder. This small but significant misalignment is beyond the capability of conventional visual-based fusion methods used clinically. The 100 mum accuracy is a step forward to register molecular activities to anatomy for high precision interventions

Three-dimensional teaching model for coronary angiography

In order to improve the understanding and interpretation of cine coronary arteriograms obtained in various angled projections, a three-dimensional wire model was constructed. The main coronary arteries and most important muscular branches are simulated by a wire skeleton. The model can be rotated to simulate the standard right and left anterior oblique and left lateral projections. The degree of rotation is indicated on the base of the model. By tilting the model, cephalad and caudad tube angulation can be simulated. By placing the model in front of the cine projector, the shadows of the wires can be superimposed upon the projected cine coronary arteriogram.This simple, inexpensive model has greatly improved the three-dimensional understanding of the coronary arterial tree in various angled and nonangled views and in our practice had led to the development of additional useful projections.

Double-lumen needle for percutaneous ureteral pressure-flow studies.

Ureteral perfusion studies in patients without preexisting renal access currently must be intermittently interrupted for intrarenal pressure measurement. A double-lumen needle has been successfully placed in four patients (two with native and two with transplanted kidneys). This permits simultaneous perfusion and intrarenal pressure monitoring yet maintains the safety and ease of use of a single skinny needle.

Case report of a complication of coil placement during transvenous embolization of spermatic veins

Coil embolization of an incompetent spermatic vein of a patient resulted in a complication from the use of a sidehole catheter. Alternative procedures are suggested to avoid the problem.