Intravascular ultrasound imaging of peripheral arteries as an adjunct to atherectomy: preliminary experience

Phase I study of weekly docetaxel and cisplatin arterial infusion for recurrent head and neck cancer

BACKGROUND

We planned a phase I study of weekly arterial infusion of docetaxel and cisplatin via a superficial temporal artery for recurrent head and neck cancer to determine the optimal dose.

METHODS

The dose of cisplatin was fixed and the dose of docetaxel was escalated from 8 mg/m(2) , with an increase of 2 mg/m(2) per step, to identify the maximum tolerated dose (MTD). In total, 4 courses of weekly chemotherapy were administered.

RESULTS

Twelve patients were recruited to this trial. The MTD of docetaxel was 14 mg/m(2) . At this dose level, dose-limiting toxicity was observed in 2 of 3 patients. One patient experienced grade 3 leukopenia, while the other experienced grade 3 leukopenia. Myelosuppression was the dose-limiting toxicity for this regimen.

CONCLUSION

The recommended dose for weekly arterial infusion of docetaxel was identified as 12 mg/m(2) combined with weekly cisplatin at 40 mg/m(2) , with 4 courses of each.

Peripheral directional atherectomy evaluated with a rotational digital angiography system

BACKGROUND

One of the factors that affect the recurrence rate after peripheral directional atherectomy (DA) is the degree of residual stenosis. A new method of peripheral DA to reduce residual stenoses was evaluated with a rotational digital angiography (RDA) system that provides both angiography and fluoroscopy at multiple projections within 360 degrees.

PATIENTS AND METHODS

Between March 1995 and July 1999, severe short segmental stenoses of six iliac arteries and two superficial femoral arteries (SFA) in eight patients were treated with the Simpson DA catheter under RDA system guidance. After pre-procedural RDA evaluation, the first series of DA were performed under ordinary PA fluoroscopic guidance. The residual stenoses were evaluated with RDA. If the residual stenoses exceeded 30%, a second series of DA were performed covering the residual plaque with the cutter window of the DA catheter. To this purpose the fluoroscopy of the RDA system was fixed in the direction in which the residual stenoses were largest and most eccentric. The end point was defined to be a residual stenosis of less than 30% evaluated with the RDA system, and the procedures were repeated until the end point was achieved.

RESULTS

Five of six iliac artery lesions were curved at the pre-procedural RDA evaluation. After the first series of DA, only two of six iliac lesions but all SFA lesions achieved the end point. Among the four other iliac lesions, three achieved the end point with one or two additional series of DA using the RDA system guidance to control the selective cuts of the residual plaques. One patient had a residual stenosis of 50% because the procedure could not be completed by balloon rupture of the DA catheter. In the patients with iliac stenoses, there was no final residual stenosis in one, and the range was from 20% to 25% in the four patients. The residual stenoses were located on the greater curvature side of the curved artery in three of these four patients.

CONCLUSION

The RDA system is a valuable tool in aiding reduction of the residual stenoses during peripheral DA. Minimal stenoses often remain on the greater curvature side of the wall because the rigid and straight metallic capsule (cylindrical housing) of the Simpson DA catheter does not completely fit the curved wall. This phenomenon was thought to be a mechanical limitation of this device.

Intravascular ultrasound in the setting of directional coronary atherectomy and percutaneous transluminal coronary rotational atherectomy

The first section of this article reviews how intracoronary ultrasound (ICUS) has been used to identify the mechanisms of action of directional coronary atherectomy (DCA) and examines the influence of plaque composition and morphology on DCA outcomes. The process of restenosis is then described. Results from trial using ICUS-guided DCA are evaluated, demonstrating how the information obtained from ICUS is being used to improve the angiographic and clinical outcomes of directional atherectomy. Finally, data are incorporated to provide practical applications for the use of DCA.

Comparison of intravascular ultrasonography and intraarterial digital subtraction angiography after directional atherectomy of short lesions in femoropopliteal arteries

PURPOSE

In this study a group of patients undergoing directional atherectomy for localized occlusive disease in the femoropopliteal arteries, the value of intravascular ultrasonography (IVUS) to improve the efficacy of plaque removal was evaluated. The findings obtained by IVUS were correlated with intraarterial digital subtraction angiography (IA DSA) performed during the procedure. In addition, the patency rates at follow-up in patients undergoing atherectomy with and without IVUS were compared.

METHODS

Forty patients were treated by atherectomy because of segmental lesions of the femoropopliteal arteries causing intermittent claudication. Twenty-two patients underwent atherectomy, guided by biplane IA DSA only, and 18 patients were also studied by IVUS. The groups were divided by means of consecutive presentation, IVUS being used in the second part of the study period. The median follow up was 16 months (range, 0 to 40 months). Variables, measured by IVUS during the procedure, were the minimal transverse luminal diameter (MTLD) and the free luminal area. Patency rates at follow-up were determined by regular color flow duplex examinations. Color-flow duplex criteria for occlusions were absence of arterial flow and, for stenosis, a ratio of peak systolic velocities at the diseased segment and a normal segment of 2.5 or greater.

RESULTS

Qualitative IVUS assessment prompted additional atherotome passages because of insufficient atheroma removal or nonaesthetic appearance of the vessel lumen in 15 of the 18 patients who underwent this examination. Only in four of these patients would abnormalities at IA DSA have been a reason for further attempts of atheroma removal. As for the quantitative findings during AT, after a first series of atherectomy passes the mean MTLD of the reference lesion resulted in an increase of the MTLD from a mean of 3.3 +/- 0.7 mm to 3.7 +/- 0.6mm (p = 0.001), and the free luminal area increased from a mean of 11.2 +/- 4.8 mm2 to 12.5 +/- 4.5 mm2 (p = 0.001). However the occurrence of restenosis during follow-up was comparable in patients monitored during the intervention by IVUS (1-year patency rate, 57%) and patients not studied by IA DSA only (1-year patency rate, 64%). In addition, the presence of an intimal dissection or a plaque rupture at IVUS examination did not predict restenosis.

CONCLUSIONS

The application of IVUS resulted in an improved luminal enlargement by directional atherectomy but not in a better 1-year patency rate.

Intravascular ultrasound imaging of peripheral arteries as an adjunct to balloon angioplasty and atherectomy

This article reviews many of the applications of intravascular ultrasound (US) imaging for peripheral arterial diseases. In vitro studies demonstrate an excellent correlation between ultrasound measurements of lumen and plaque cross-sectional area compared with histologic sections. In vivo clinical studies reveal the enhanced diagnostic capabilities of this technology compared with angiography. Intravascular US imaging can provide valuable information on the degree, eccentricity, and histologic type of stenosis before intervention, and on the morphological changes in the arterial wall and the extent of excision after intervention. Intravascular US may also serve as a superior index for gauging the diameter of balloon, stent, laser probe, and/or atherectomy catheter appropriate for a proposed intervention. Significant new insights into the mechanisms of balloon angioplasty and atherectomy have been established by intravascular US findings. Intravascular US imaging has been shown to be a more accurate method than angiography for determining the cross-sectional area of the arterial lumen, and for assessing severity of stenosis. Quantitative assessment of the luminal cross-sectional area after the balloon dilatation should be more accurate than angiography as intimal tears or dissections produced by the dilatation may not be accurately evaluated with angiography. At the present time, intravascular US is still a controversial imaging technique. Outcome studies are currently being organized to assess the clinical value and cost effectiveness of intravascular ultrasound in the context of these interventional procedures.