Microperfusion enhancement after TMLR in chronically ischemic porcine hearts.

OBJECTIVE: The purpose of this study was to determine the effect of transmyocardial laser revascularization (TMLR) on myocardial perfusion and function in chronically ischemic myocardium. METHODS: In the first operation a stenosis of the left anterior descending artery was created in 20 open-chest anesthetized pigs to implement this ischemic model. In contrast, four pigs served as controls (thoracotomy only). Seven days later (2nd operation), all animals were studied at baseline by analyzing different parameters of perfusion (radioactive microspheres), function, and intramyocardial pressure. Afterwards, pigs who received a left anterior descending artery stenosis were randomized into one of three groups: animals in laser group 1 (n=7) received one and in laser group 2 (n=7) two laser channels per cm(2) in the left anterior descending artery territory. Animals of the ischemic group (n=6) underwent the same procedures without transmyocardial laser revascularization. Three months later, the animals were re-studied (3rd operation) and additional analysis of histochemistry and myocardial water content was performed. RESULTS: Regional myocardial blood flow (RMBF) in laser group 2 revealed statistically higher RMBF values compared to the ischemic group (0.39+/-0.13 versus 0.14+/-0.12 ml/min/g; P=0.043), after 3 months, whereas the absolute RMBF had not increased compared to the 1-week baseline values. Left ventricular stroke work index (LVSWI) at rest and under stress did not show any improvement compared to the initial values in all study groups (P=ns). Nevertheless, laser group 1 demonstrated relatively higher LVSWI(max) values compared to the ischemic (1.33+/-0.19 versus 0.93+/-0.16 mJ/kg; P=0.03) and laser group 2 (1.33+/-0.19 versus 1.02+/-0.15; P=0.024). Regional contractility of laser groups 1 and 2 recovered after 3 months (which had deteriorated shortly after transmyocardial laser revascularization) and increased under stress (100% versus 144.33+/-46.42, P=0.029 and 100% versus 116.26+/-21.06, P=0.034; respectively). In contrast, the corresponding ischemic group values were not different from initial values (P=ns). CONCLUSIONS: This model of chronic regional ischemia demonstrates that CO(2)-laser revascularization significantly improves microperfusion and regional function, whereas the overall perfusion and global LV function is unchanged.

Atherectomy. Early use of three different methods.

The authors report their initial experience in 52 patients with three different techniques of peripheral artery atherectomy--the Tracwright (Kensey), used in 19 patients, the Simpson AtheroCath, used in 19 patients and the transluminal extraction catheter, used in 14 patients. The indications for atherectomy were claudication in 42 (80%) and limb-threatening ischemia in 10 (19%). There were no deaths. Complications included three arterial perforations, one thrombosis and one groin hematoma requiring operative evacuation. There were no distal embolizations. Atherectomy was initially unsuccessful in 15 (29%) patients. For the successfully completed procedures, the 1-year primary patency rates were as follows: Tracwright (Kensey) catheter 56%, Simpson catheter (63%) and transluminal extraction catheter (0%). Use of subsequent nonoperative procedures on recurrent stenoses produced secondary patency rates of 77% for the Tracwright (Kensey) technique, 80% for the Simpson catheter technique and 78% for the transluminal extraction catheter technique. The authors conclude that their early results justify further evaluation of these three techniques. Use of the transluminal extraction catheter is associated with higher rates of occlusion and restenosis.

Laser-assisted angioplasty: an intervention and backup system for catheterization laboratories conducting angioplasty.

This article reports preliminary results of laser-assisted angioplasty intervention. Early results indicate successful intervention in peripheral arteries.

Laser-assisted balloon angioplasty: initial 18 months' experience.

The authors describe their initial 18-month experience with laser-assisted balloon angioplasty (LABA) of femoral arteries in 44 patients. Primary patency was achieved in 28 patients, but within 30 days the artery became occluded in 9 of them. Perforation occurred much more frequently early in the study. Complications associated with antegrade femoral artery puncture have led to more liberal use of LABA through an operative approach in the femoral artery. Attention to technical detail is critical. When LABA fails it does not appear to worsen the patient's condition clinically or radiologically. Endovascular procedures are undergoing continued, rapid change, so ongoing development and assessment of results are necessary for those who perform LABA.