“Angioplasty-First” Approach for Limb Salvage in Asian Patients with Critical Limb Ischemia: Outcomes from 3,303 Angioplasties on 2,402 Limbs in a Single Tertiary Hospital

Clinical question
Is an “angioplasty-first” approach for critical limb ischemia safe and effective in Asian patients?

Take away point
This large retrospective study demonstrated that percutaneous transluminal angioplasty for critical limb ischemia was safe and effective in Asian patients.

Reference
Ni, W.W., Leong, S., Irani, F., Patel, A., Damodharan, K., Venkataranasimha, N., Chandramohan, S., Kumar, P., Chua, J., Gogna, A. and Da Zhuang, K., 2020. “Angioplasty-First” Approach for Limb Salvage in Asian Patients with Critical Limb Ischemia: Outcomes from 3,303 Angioplasties on 2,402 Limbs in a Single Tertiary Hospital. Journal of Vascular and Interventional Radiology, 31(12), pp.1969-1977.

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Study design
Retrospective single center review of 3,303 angioplasty procedures on 2,402 limbs in 1,968 Asian patients with CLI with Kaplan-Meier plot generated limb salvage rates. Univariate and multivariate Cox regression analysis was used to examine associations between clinical predictors and outcomes of major amputation and mortality.

Funding source
None or self-funded.

Setting
Academic hospital. Singapore General Hospital, Singapore.



Figure. Plantar arch integrity, a measure used in this present study to assess technical success on completion angiogram. A) Complete plantar arch. B) Patent dorsalis pedis artery only. C) Patent lateral plantar artery only. D) Absent plantar arch.

Summary

Critical limb ischemia, defined as the presence of rest pain or tissue loss (ulcers or gangrene) for > 2 weeks, was recommended to receive endovascular therapy for TASC (Inter-Society Consensus for Management of Peripheral Arterial Disease) type A and B lesions, and bypass surgery for TASC type C and D lesions. However, patient comorbidities commonly restricted patients from receiving surgical treatment. Given BASIL (Bypass versus Angioplasty in Severe Ischemia of the Leg) trial’s reporting of similar amputation-free survival and overall survival for endovascular and surgical treatment, endovascular approach has become common practice with several predictive and risk stratification models developed. Nevertheless, literature specifically in a Asian population remained scarce.

A prospective collected critical limb ischemia database with endovascular treatment was retrospectively reviewed for the time period between 2005 to 2015, producing information on 3,303 angioplasty procedures in 2,402 Rutherford category 4-6 limbs (90% had tissue loss) of 1,968 patients. All procedures were performed with 5-mm Sterling and 3-mm Savvy balloons; no drug-coated balloons or drug-eluting stents were used. Completion angiograms were reviewed for number of runoff vessels and completeness of the plantar arch. Major amputation and overall survival were used as outcome variables. Univariate and multivariate (with variables that achieved the significance level of 0.20 in the univariate analysis) Cox regression analysis was used to examine associations between clinical predictors and outcomes of major amputation and mortality.

Initial technical success rate was 94% with bailout stent placed in 11% of the cases. Repeat percutaneous transluminal angioplasty was required in 30% of procedures. During the follow-up period, the limb salvage rates at 1, 3, 5, and 10 years were 75%, 73%, 72%, and 62%, respectively. Age < 69 y, race, ESRD, and repeat intervention were independent predictors for both major amputation and mortality. Predictive models were built based on the results of the multivariate Cox regression analyses.

Commentary

The authors in this paper retrospectively reviewed the safety and effectiveness of percutaneous transluminal angioplasty first approach for Asian patients presenting with CLI. The results were comparable to major studies published on Western population and further strengthened the literature behind critical limb ischemia endovascular management. Predictive models for limb salvage and overall survival can be used in clinical practice for prognostic purposes and better communication with patients and consulting clinicians. The authors should be applauded for their efforts and sharing of these important treatment outcome details on a large, well-established database. Future prospective trials, with potential inclusion of newer technique and devices, are still needed for validation of the results and predictive models presented in the current study.

Post Author
Ningcheng (Peter) Li, MD, MS
Integrated Interventional Radiology Resident, PGY-4
Department of Interventional Radiology
Oregon Health and Science University, Dotter Interventional Institute

@NingchengLi

Predictors of Occlusion of Hepatic Blood Vessels after Irreversible Electroporation of Liver Tumors

Clinical question
What factors predict occlusion of the portal or hepatic veins following irreversible electroporation (IRE) for liver tumors?

Take-away point
Vessel occlusoin can be predicted based on vessel size (<=4 mm) and location (within the ablation zone)

Reference
Masashi Tamura et al. Predictors of Occlusion of Hepatic Blood Vessels after Irreversible Electroportaion of Liver Tumors. Journal of Vascular and Interventional Radiology. 2020: 31; 2033-2042.

Click here for abstract

Study design: 

Retrospective Cohort Analysis

Funding source: 

Self-funded

Setting: 

Single-Center



Figure 1. A 76-year old man with colorectal cancer metastasis in segment 8. (a) CT before the procedure shows the metastatic liver tumor in segment 8 from colorectal cancer (arrowhead). Three portal vein branches were running near the tumor measure 5 mm (vessel A), 3.5 mm (vessel B), and 5 mm (vessel C) from theventral side. (b) CT after the procedure shows teh ablation zone as a nonenhanced liver area. The 3 portal vein branches were judged as adjacent (vessel A: arrow A), within (vessel B: arrow B), and within (vessel C: arrow C). (c) On follow-up CT, although vessel A (arrow A) and vessel C (arrow C) remained patent, vessel B was occluded.

Summary

Unlike the more common modalities for percutaneous ablation, irreversible electroporation (IRE), is predominantly non-thermal. This avoids susceptibility to heat sink effects which can inhibit microwave ablation (MWA) and radiofrequency ablation (RFA1. While it has been suspected that IRE would not affect vessel patency, unlike MWA and RFA), this has not been fully studied.

This study evaluated 39 patients who underwent IRE to hepatic lesions and evaluated 33 portal veins and 64 hepatic veins that were within or adjacent to the ablation zone. On follow up imaging, 37% of portal veins and 27% of hepatic veins were occluded. Vessels <= 4mm showed a significantly higher rate of occlusion compared to vessels > 4 mm (72.7% versus 18.1% for portal veins and 54.8% vs 0% for hepatic veins). Additionally, vessels within the ablation zone were occluded at a significantly higher frequency than adjacent vessels (55.6.7% versus 13.3% for portal veins and 45.4% vs 6.4% for hepatic veins).

Commentary

When choosing an ablation modality, common thinking is that IRE is preferred in locations where heat sink could prohibit a full ablation and where vessel damage needs to be minimized. While IRE does not suffer limitations of heat sink, potentially, we have minimized the possible affects IRE may have on vessels in and around the ablation margin. As this study demonstartes, venous occlusion is predictable using size and location compared to the ablation cavity. Given the clear difference in rate of occlusion based on size, central lesions are likely still great candidates for IRE where the portal veins and/or hepatic veins are likely to be larger than 4 mm, however potential venous occlusion should not be completely discounted.

Post Author:
David M Mauro, MD
Assistant Professor
Department of Radiology, Vascular and Interventional Radiology
University of North Carolina
@DavidMauroMD