Laser angioplasty in peripheral vascular disease: Symptomatic versus hemodynamic results

Treatment of Difficult, Calcified Lesions: Plaque Modification Strategies

Endovascular management of peripheral arterial disease is continually evolving. Most changes focus on addressing the challenges that hinder optimal patient outcomes; one of the most significant is how to best treat calcified lesions. Hardened plaque results in a variety of technical issues including impaired device delivery, decreased luminal revascularization, poor stent expansion, heightened risk of in-stent stenosis or thrombosis, and increased procedural time and cost. For this reason, plaque modification devices have been developed to mitigate this issue. This paper will describe these strategies and provide the reader with an overview of devices that can be used to treat chronically hardened lesions.

Laser Atherectomy for the Treatment of Peripheral Arterial Disease

BACKGROUND

The aim of the study was to investigate the clinical results of laser atherectomy in the treatment of peripheral arterial disease.

METHODS

Retrospective analysis of consecutive patients underwent laser atherectomy at a single institution during a 7-year period by vascular surgeons and interventional cardiologists in a tertiary university-affiliated hospital. Clinical data were retrieved from patient charts and hospital electronic medical records along with the associated arteriograms.

RESULTS

A total of 461 lesions in 343 limbs were treated in 300 patients with a mean age of 70 years. The indication was critical limb ischemia (CLI) with rest pain or tissue loss in 227 (66%) of interventions and claudication in 116 (34%). All procedures included an associated balloon angioplasty, while stenting was performed in 33%. Technical success was achieved in 99% with only 2 (<1%) cases with an acute procedure-related complication requiring surgical intervention. At a mean follow-up of 28 months (range, 1-87 months; median 24 months), 156 patients (45%) became asymptomatic or achieved significant clinical improvement (resolution of tissue loss or rest pain), 60 (17%) remained with CLI, 30 (9%) had a major proximal amputation, and 18 (5%) had a minor amputation. Freedom from major amputation was 90% at 5 years by life-table analysis. Univariate statistical analysis demonstrated the risk of a major amputation to be associated with diabetes, hemodialysis, and tissue loss (P < 0.05 to P < 0.005), while multivariate logistic regression analysis indicated diabetes to be overwhelmingly important (RR: 4.84; 95% confidence interval [CI]: 1.1-21.3; P < 0.05). In a similar manner, multivariate analysis indicated dialysis (RR: 2.46; 95% CI: 1.01-5.98; P < 0.05) and CLI (RR: 2.27; 95% CI: 1.42-3.65; P < 0.01) were associated with higher likelihood for lack of clinical improvement. There was no difference in major amputation rates between surgeons and interventional cardiologists (RR: 1.5; 95% CI: 0.7-2.1; P < 0.1) although it was 3 times more likely for the patients treated by surgeons to suffer from CLI (odds ratio: 3.2; 95% CI: 1.9-5.4; P < 0.0001).

CONCLUSIONS

Laser atherectomy is a safe and useful adjunct in limb salvage. Diabetics have much higher probability of requiring a proximal amputation, while those on dialysis and with CLI are least likely to gain clinical benefit.

Laser Atherectomy for Lower Extremity Revascularization: An Adjunctive Endovascular Treatment Option

Excimer laser atherectomy (LA) employs precision laser energy control (shallow tissue penetration) and safer wavelengths (ultraviolet as opposed to the infrared spectra in older laser technology), which decreases perforation and thermal injury to the treated vessels. Though extensively used by cardiologists for severe obstructive coronary artery disease, peripheral interventionalists have not accepted LA as a routine adjunctive technique for stenotic or occluded vessels. We report herein the technical and clinical outcomes with LA for complex peripheral vascular disease in patients deemed high-risk for conventional surgical revascularization. Over a 6-month period, 19 lesions in 15 high-risk patients (mean age 72 ±10 years) were treated with LA (308-nm spectral wavelength) followed by balloon angioplasty for limb-threatening ischemia (n=10) and severe disabling claudication (n=5). The lesions were located at the superficial femoral artery (n=8), popliteal artery (6), and/or tibial vessels (5). The mean occlusion length was 10.3 ±2.3 cm. Laser catheter choice ranged from 1.4 to 2.5 mm depending on the target vessel diameter. Clinical examination, duplex ultrasound, and ankle-brachial indices were performed in follow-up visits. Immediate technical success was achieved in 16 (84%) lesions. In the 3 technical failures, inability to cross the lesion with a wire (n=2) or vessel perforation (n=1) precluded successful LA. Overall, primary patency as assessed by duplex was 57% (superficial femoral artery 71%, popliteal 60%, tibial vessels 25%). Clinical improvement was seen in 10 lesions (77%) that were successfully treated initially. One patient required below-knee amputation. At an average of 2-year follow-up, 6 patients who were initially successfully treated were alive (46%), including 3 patients (50%) with stable symptoms without the need for major amputation. Laser atherectomy is a useful adjunctive revascularization technique for high-risk patients with limb-threatening ischemia. This technique is especially beneficial in the treatment of ostial lesions, which may be prone to distal embolization, as well as total occlusions that can be traversed by a guide wire but not a balloon. Vascular surgeons should add LA to their endovascular armamentarium for the treatment of complex peripheral vascular disease in the high surgical risk patients. Further study of clinical outcome measures and comparison to other interventional techniques are warranted.

Can endovascular therapy of infrainguinal disease for claudication be justified?

Traditionally, patients with exercise-induced lower extremity ischemia (claudicants) have been treated conservatively. It is important to remember that this is not because the pain of claudication is less important than pain due to other problems, but because the only 'cure', operative bypass, has been judged too invasive by both patient and physician. Recent data suggest that endovascular treatment of atherosclerotic disease below the inguinal ligament yields good short-term results, with low periprocedural morbidity and does not compromise future surgical alternatives in the long-term. If this approach is to be used as nonoperative treatment for the pain of claudication, however, the authors suggest that long-term success may be less important than the absolute minimization of short-term and periprocedural risk. The authors believe that given the results of modern endovascular therapy it is increasingly less acceptable to tell claudicants to live with their pain if conservative therapy fails. The option of endovascular treatment for infrainguinal atherosclerotic disease should be discussed with every patient whose claudication is significant, and considered as a treatment option in place of continued pain. This approach should be judged against conservative therapy for claudication, not against surgical bypass for limb threat.

A comparative evaluation of polytetrafluoroethylene, umbilical vein, and saphenous vein bypass grafts for femoral-popliteal above-knee revascularization: a prospective randomized Department of Veterans Affairs cooperative study

PURPOSE

Currently, the choice of a vascular prosthesis for a femoral-popliteal above-knee arterial bypass graft is left to the surgeon's preference, because the available information on comparative evaluations is inconclusive. The Department of Veterans Affairs (VA) Cooperative Study 141 was established to identify whether improved patency exists with different bypass graft materials for patients with femoral-popliteal above-knee bypass grafts.

METHODS

Between June 1983 and June 1988, 752 patients at 20 VA medical centers were randomized to receive either an externally supported polytetrafluoroethylene (PTFE; N = 265), human umbilical vein (HUV; N = 261), or saphenous vein (SV; N = 226) for an above-knee femoral-popliteal bypass graft. The indication for the bypass grafting operation was limb salvage in 67.5% of the patients. Patients were observed every 3 months for the first year and every 6 months thereafter. All patients were instructed to take aspirin (650 mg) daily for the duration of the study.Doppler-derived ankle-brachial indices (ABIs) were determined preoperatively and serially postoperatively. A bypass graft was considered to be patent when the Doppler-derived postoperative ABI remained significantly improved (more than 0.15 units higher than their preoperative value) and additional objective information, such as angiograms or operations, did not contradict these observations. Patency failure also included bypass grafts that were removed because of an infection or aneurysmal degeneration. Patency rates were compared by using the Kaplan-Meier life table analysis.

RESULTS

The cumulative assisted primary patency rates were statistically similar among the different conduit types at 2 years (SV, 81%; HUV, 70%; PTFE, 69%). After 5 years, above-knee SV bypass grafts had a significantly (P </=.01) better patency rate (73%) than HUV bypass grafts (53%), which had a significantly (P </=.01) better patency rate than PTFE bypass grafts (39%). Limb salvage was slightly worse with PTFE conduits. The number of bypass graft thromboses and major amputations within the first 30 days was highest in the HUV group.

CONCLUSION

The overall results of this prospective randomized study suggest that the SV should be considered as the bypass graft of choice for femoral-popliteal above-knee reconstruction and that, when a prosthetic bypass graft is used, an HUV should also be considered as an alternative choice to PTFE.

Subintimal versus intraluminal laser-assisted recanalization of occluded femoropopliteal arteries: one-year clinical and angiographic follow-up

PURPOSE

To compare the prolonged effect of subintimal versus intraluminal recanalization of occluded femoropopliteal arteries.

PATIENTS AND METHODS

Recanalization of an occluded femoropopliteal artery was attempted in 63 patients (51 men, 12 women; mean age, 63 years) with lifestyle-limiting claudication and at least one patent distal artery. After assessment of baseline clinical and angiographic variables, mechanical passage was first attempted with use of a laser catheter with a 2.2-mm- diameter hemispherical contact probe that was connected to a neodymium: yttrium-aluminum-garnet laser. In case of failure, the laser was activated at 1-second pulses of 15 W. In some cases additional guide-wire and catheter manipulations were used. Successful recanalization was followed by standard balloon dilation. An intense antithrombotic regimen was used.

RESULTS

The occluded artery could be entered in 62 of 63 patients. The catheter was assumed to have followed a subintimal course in 20 patients (group A) and an intraluminal course in 42 patients (group B). Successful recanalization was achieved in 17 patients (85%) of group A and in 36 (86%) of group B. No significant differences were found in clinical and angiographic follow-up measurements between the two groups. The angiographic cumulative primary patency rate (open vs closed) at 1 year was 93% +/- 6 in group A and 93% +/- 4 in group B. The cumulative restenosis/reocclusion-free patency rate was 63% +/- 13 and 65% +/- 9 for groups A and B, respectively. Median length of the original occlusion (8.0 cm in group A vs 4.5 cm in group B) was the only distinguishing baseline variable between the groups (P < .02) and was also the single independent predictor of recurrent flow limitation (P = .0017). Significant complications were distal embolization in three patients, followed by death in one patient and puncture site bleeding in two patients.

CONCLUSION

The 1-year clinical and angiographic results of assumed subintimal and intraluminal recanalization are comparable. Thus, a subintimal course per se should not be regarded as a failure of the procedure.

Arterial mapping with color flow duplex imaging of the lower extremities after excimer-laser-assisted angioplasty

The purpose of the present study was to evaluate the role of color flow duplex imaging (CFDI) in the follow-up of patients who have undergone excimer-laser-assisted angioplasty of peripheral arteries. Sixty-one patients (40 men and 21 women) were studied (mean age +/- SD sixty-three +/- nine years). All patients were affected by peripheral vascular disease and, for this reason, underwent percutaneous excimer-laser-assisted angioplasty. Digital angiography and CFDI were performed before the laser procedure. CFDI was repeated at months 1, 3, 6, 9, and 12 after the laser procedure, whereas angiography was repeated after twelve months. Common, superficial, and profunda femoral arteries and popliteal arteries were visualized in looking for the presence of lesions and occlusions, and spectral analysis of Doppler signals was recorded. After the initial success, claudication was reported again by 9 patients, 7 of whom showed total occlusions. All reocclusions were discovered by CFDI and confirmed by angiography; 3 of these 7 patients underwent a second laser procedure. The remaining 2 symptomatic patients showed patent vessels and did not undergo angiography. Another 9 patients redeveloped an occlusion, unsuspected from clinical history and symptoms. All the reocclusions, confirmed by angiography, were diagnosed by CFDI. The data show that CFDI provides an accurate noninvasive technique for following up patients after excimer laser angioplasty, allowing for asymptomatic reocclusions to be recognized and treated if necessary, and permitting symptoms not due to reocclusions to be properly identified, thus avoiding unnecessary angiography.

Laser angioplasty

Laser energy has the potential for selective ablation of atherosclerotic plaque through minimally invasive means. As currently practiced, laser angioplasty requires the adjunct of balloon angioplasty in most cases and has limited application compared with more conventional methods of revascularization. However, new advances in guidance systems, delivery devices, and laser sources may allow realization of the full benefit of this technology at some point in the future.

Vascular applications of lasers

There have been major advances in laser technology and in our understanding of the effects of laser energy on blood vessels. This, in turn, has led to the many clinical applications of lasers in patients with vascular disease. The clinical results of laser endarterectomy, laser angioplasty, laser-assisted balloon angioplasty, laser-assisted vascular anastomoses, and the future of lasers in cardiovascular disease are discussed.