Timothy J. Bowker

Percutaneous transluminal coronary angioplasty in chronic coronary artery occlusion

OBJECTIVES This study was conducted to determine the procedural success rate, complication rate and long-term outcome of percutaneous transluminal coronary angioplasty in chronically occluded coronary arteries. BACKGROUND Coronary angioplasty of chronically occluded vessels has a lower success rate than has angioplasty of nonoccluded vessels, but it is frequently considered safe because the target vessel is already occluded. The purpose of this study was to determine the reliability of these assumptions at our institution, with the objectives stated above. METHODS We identified from the angioplasty data base at our institution 100 consecutive coronary angioplasty procedures performed between 1987 and 1991 for chronic total occlusion, defined as complete occlusion (Thrombolysis in Myocardial Infarction [TIMI] grades 0 and 1 flow) for > or = 3 months. The records of the 95 patients who underwent these procedures were reviewed to determine procedural outcome and medium-term results. RESULTS Procedural success was obtained in 47 occluded vessels (47%). Significantly fewer successes were obtained in the right coronary artery (26.8%) than in either the left anterior descending (57.1%) or the left circumflex (45%) coronary artery (p < 0.05). A procedural failure without serious adverse consequences occurred in 45 procedures (45%), but in eight patients (right coronary artery in five, left anterior descending artery in three) attempted recanalization was complicated by extensive coronary dissection with acute myocardial ischemia, and one of these patients died. There were no emergency operations, but elective coronary artery bypass surgery was undertaken in 26 patients (in 3 after extensive dissection, in 7 after an apparently good result and in 16 in whom the procedure failed). At 12 months after the procedure, 64.1% of those with a procedural success were event free compared with 32.6% of those whose procedure was both unsuccessful and uncomplicated (p < 0.025) and 25% of those in whom it was unsuccessful and complicated by coronary dissection (p < 0.025). CONCLUSIONS In this series of recanalization of chronically occluded coronary arteries, there was a low procedural success rate, particularly for the right coronary artery. However, when procedural success was obtained, the long-term outlook was good. The overall risk of coronary dissection was comparable to the risk in nonoccluded vessels but was particularly high in the right coronary artery (13%).

Differential restenosis rate of individual coronary artery sites after multivessel angioplasty: Implications for revascularization strategy

BACKGROUND Restenosis is a major limitation of angioplasty. In this analysis we assessed the effects of lesion site and quality of dilatation on restenosis rate in the Coronary Angioplasty versus Bypass Revascularization Investigation population who underwent angioplasty. METHODS The angiographic quality of the successful angioplasty revascularization at each site was assessed, and the subsequent restenosis rate was determined. Restenosis was defined by the need for a second angioplasty at the initial site or by surgical coronary bypass grafting at or distal to the initial site. RESULTS The restenosis rate was unaffected by quality of dilatation but was significantly more common in the proximal left anterior descending artery compared with other sites, whether or not optimal dilatation had been achieved (relative risk 2.0 and 1.9, respectively). CONCLUSION Revascularization strategies in multivessel disease should consider the presence or absence of a proximal left anterior descending artery target. Furthermore in studies in which restenosis is an outcome of interest, an allowance should be made for the distribution of target disease.

Ball-Tip Fibres For Laser Angioplasty: Comparison Of Wavelengths From A Pulsed Neodymium-Yag Laser.

A new ball-tip fibre optic device has been assessed for the purpose of laser angioplasty. A pulsed Neodymium-YAG laser producing 100 p.s pulses at a repetition rate of 10 Hz was used to ablate human cadaver arterial tissue using approximately 500 mJ per pulse at a wavelength of 1064 nm or 300 mJ at a wavelength of 1.3 μm. Both wavelengths are capable of ablating atheroma with little histological evidence of surrounding thermal damage. Crater depths of about 5 μm per Joule were produced using 1064 nm with normal tissue exposed under saline. Crater depth increases by about 50% when exposures are carried out under blood and when diseased arterial tissue is exposed the crater depth is almost doubled. Depth of ablation with a wavelength of 1.3 μm is 3 to 4 times greater than with 1064 nm for the same exposure and a similar increased response is seen for diseased tissue or in the presence of blood. Further experiments at 1064 nm have shown that the ball-tip device has advantages over bare fibre or sapphire tipped devices in the recanalisation of occluded femoral vessels in an artificial circulation.

Clinical coronary laser balloon angioplasty: effect on ergonovine responsiveness

Laser balloon angioplasty involves delivery of continuous wave Nd-YAG laser energy radially from the surface of a specially designed a.ngioplast.y balloon directly to the luniirial surface of an arterial segment immediately after it.s succeasfu] dilatation by conventional balloon angioplasty, the purpose being to fuse loose flaps and disrupted atheroinatous plaque thermally hack against the arterial wall and to reduce elastic recoil and smooth muscle proliferation, in an attempt to prevent re stenosis . Ergonovirie stimulates arterial wall smooth muscle, normally causes arteries to constrict and is used in the diagnosis of coronary artery spasm. Three patients were treated with laser balloon angioplasty, each receiving 380 3 over 20 seconds (30 W for 5 a, 18 W for 5 s & 14 W for 10 5) . The minimum lumirial diameter of the treated arterial segment was measured angiographically before and after conventional balloon angioplasty, immediately after laser balloon angioplasty and again 1 month later both before and after ergonovine was given. The measurements were (respectively, in mm): 1.03, 1.71, 1.85, 2.37 and 2.37 in patient 1; 0.30, 1.54, 1.85, 2.07 and 2.11 in patient 2; and 0.98, 1.76, 2.27, 2.40 and 2.40 in patient 3. The before and after ergonovire measurements were almost identical, suggesting that laser balloon angioplasty abolishes ergonovine responsiveness for at least up to one month following the procedure, and thus might be of use in treating coronary artery spasm which is resistant to medical therapy.