Catheterization and cardiovascular diagnosis最新文献

We designed a novel guide catheter specifically for interventions to the left coronary artery via a right upper limb approach. The catheter has a novel first loop design which utilizes the angle between the right subclavian and innominate arteries for support. The first loop introduces the catheter into the correct position and generates powerful and coaxial back-up power. We report successful implantation of Palmaz-Schatz stents in five cases using this 6 Fr. catheter.

A small gap between stent struts is essential to support the vessel wall, prevent elastic recoil, and prevent intimal flaps from prolpasing into the lumen. We defined Gap Index as the ratio of strut width divided by the percent of the vessel wall area covered by the stent metal, and proved mathematically that this index relates inversely to the total length of stent struts (or coil), and directly related to stent cell size. Twenty-four (12 tubular and 12 coil) stents from 17 manufacturers were analyzed. Strut width in the tubular and coil groups was 354.1 +/- 276.0 and 955.9 +/- 553.9 microm, respectively (P < 0.001). The relative metallic surface area (RMS) in the tubular and coil groups for 3 mm stent diameter was 16.0 +/- 4.6 and 10.6 +/- 3.7%, respectively (P < 0.005). Great variations in Gap Index were found amongst different stents, with up to 100-fold. Gap Index in the tubular and coil groups for 3 mm stent diameter was 24.4 +/- 21.7 and 105.8 +/- 97.5 units, respectively (P = 0.001). Thus, coil stents have a smaller relative metallic surface area despite increased strut width. This is the result of reduced total strut length and fewer and larger cells, as represented by a higher Gap Index. This information may be useful for new stents designs.

Radial artery access for coronary artery angioplasty is a cost-effective alternative to other vascular entry sites. The initial series of patients using the radial artery site for an operator without experience in using arm access for coronary artery angioplasty was evaluated. Clinical success was achieved via the radial artery in 87% of 32 lesions and 84% of 27 patients. The major feature limiting success via the arm was radial/brachial artery spasm, which occurred in 30% of cases (clinical success: 50% with spasm vs. 95% without spasm, P < 0.05). Spasm was more common in patients with peripheral vascular disease and in hypertensive patients not treated with calcium channel blockers prior to angioplasty. Coronary angioplasty via the radial artery may be successfully performed even by the interventionalist inexperienced in arm access. Vascular spasm is an important feature that limits the ability successfully to complete coronary angioplasty via the radial artery.

Despite the improvements afforded by intracoronary stenting, restenosis remains a significant problem. The optimal physical properties of a stent have not been defined. We compared the vascular response to a thermoelastic self-expanding nitinol stent with a balloon-expandable tubular slotted stainless steel stent in normal porcine coronary arteries. Twenty-two stents (11 nitinol and 11 tubular slotted) were implanted in 11 miniature swine. The nitinol stents were deployed using the intrinsic thermal properties of the metal, without adjunctive balloon dilation. The tubular slotted stents were implanted using a noncompliant balloon with a mean inflation pressure of 12 atm. Intravascular ultrasound (IVUS) and histology were used to evaluate the vascular response to the stents. The mean cross-sectional area (CSA) of the nitinol stents (mm2) as measured by IVUS increased from 8.13 +/- 1.09 at implant to 9.10 +/- 0.99 after 28 days (P = 0.038), while the mean CSA of the tubular slotted stents was unchanged (7.84 +/- 1.39 mm2 vs. 7.10 +/- 1.07 mm2, P = 0.25). On histology at 3 days, the tubular slotted stents had more inflammatory cells adjacent to the stent wires (5.7 +/- 1.5 cells/0.1 mm2) than the nitinol (3.9 +/- 1.3 cells/0.1 mm2, P = 0.016). The tubular slotted also had increased thrombus thickness (83 +/- 85 microm) than the nitinol stents (43 +/- 25 microm, P = 0.0014). After 28 days, the vessel injury score was similar for the nitinol (0.6 +/- 0.3) and the tubular slotted (0.5 +/- 0.1, P = 0.73) designs. The mean neointimal area (0.97 +/- 0.46 mm2 vs. 1.96 +/- 0.34 mm2, P = 0.002) and percent area stenosis (15 +/- 7 vs. 33 +/- 7, P = 0.003) were significantly lower in the nitinol than in the tubular slotted stents, respectively. We conclude that a thermoelastic nitinol stent exerts a more favorable effect on vascular remodeling, with less neointimal formation, than a balloon-expandable design. Progressive intrinsic stent expansion after implant does not appear to stimulate neointimal formation and, therefore, may provide a mechanical solution to prevent in-stent restenosis.

Procedural and 6-mo clinical outcomes were evaluated in 34 consecutive patients who had stenting (<40 mm) of a long segment of coronary artery. Procedural success was achieved in 32 (96%) patients. Before stenting, 32 (96%) patients had Canadian Cardiovascular Society Class 3 or 4 angina compared to 7 (21%) at 6-mo follow-up (P<0.001). Eleven patients (32%) suffered either acute/subacute stent thrombosis (n=4) or restenosis (n=7). On logistic regression distal reference diameter <2.5 mm (odds ratio 26, P<0.01) and previous cardiac intervention (odds ratio 9.0, P<0.01) were independent predictors of a major adverse event during follow-up. There was no significant association between outcome and indication for stenting, type of stent, or use of ticlopidine and aspirin. These results indicate that distal vessel diameter <2.5 mm is a powerful predictor of subacute thrombosis or restenosis after long coronary artery stenting.

Several techniques have been developed to retrieve catheter and guide wire fragments that have embolized to the heart and pulmonary vasculature. In most instances, retrieval of the embolized fragments is performed soon after the event has occurred. In this report, we summarize our experience with the removal of these fragments in 3 children after a significant amount of time had elapsed since the time of embolization. The embolized catheter and guide wire fragments were removed without any complications. We also describe the techniques used for their removal, and the problems encountered during the removal of these "old" foreign bodies.

The long-term patency of saphenous vein graft (SVG) lesions after intervention has been shown to be improved with new interventional techniques such as stents. Long-term outcome of patients undergoing successful angioplasty of totally occluded old SVGs with new devices is unknown. From July 1994 to June 1996, 19 patients with totally occluded old SVGs had successful angioplasty with new interventional techniques. Mean SVG age was 123 +/- 8 mo. Thrombolysis in myocardial infarction trial (TIMI) flow was 0 in all target lesions. TIMI 2 or 3 flow was restored after angioplasty in all patients. Intracoronary urokinase, transluminal extractional atherectomy, and stenting were used in 14, 12, and 6 patients, respectively. There was one in-hospital death due to ongoing myocardial infarction, no recurrent infarction, and no repeat angioplasty or bypass surgery in the hospital. At follow-up of 21 +/- 1 mo, there was one sudden death and one myocardial infarction. Five patients had repeat coronary bypass surgery, and 4 had repeat angioplasty. Thirteen patients remained asymptomatic, and 4 had angina. The long-term outcome of patients who had successful reopening of occluded old SVGs is encouraging in this small sample.