Saphenous vein graft intervention

• Svg pathology.

• Natural course.

• Problems in interventions.

• Techniques.

• Procedure related complications.

• Role of stents and supportive medications.

Background

*Ischemic symptoms recur in 4-8% of patients/year following CABG.

*Recurrence of symptoms can be attributed to progression of nativevessel coronary disease (5%/year) and bypass conduit occlusion,particularly SVG failure (7% in week 1; 15-20% in first year; 1-2%/yrduring the first 5-6 years, and 3-5%/yr in years 6-10 postop).

*At 10 years postop, approximately half of all SVG conduits are occludedand only half of the remaining patent grafts are free of significantdisease.

5-10% PCI case volume.

Alexander JH. JAMA 2005; 16;294(19):2446-2454

Widimsky P. Circulation 2004 30;110(22):3418-3423

PATHOPHYSIOLOGY OF SAPHENOUS VEIN GRAFT DISEASE

• Saphenous vein graft disease occurs in three phases:

• (1) early (before hospital discharge) (thrombosis)

• (2) intermediate (1 month to 1 year) (intimal hyperplasia)

• (3) late (beyond 1 year) (atherosclerosis)

Early failure

• Within 30 days

• acute vein graft thrombosis (60%)

• focal stenoses at the proximal or distal anastomotic sites

• kinked grafts.

• Urgent coronary angiography

• Emergency percutaneous intervention if required.

• within 1 to 12 months.

• due to perianastomotic graft stenosis from intimal hyperplasia.

• mid SVG stenosis from fibrous intimalhyperplasia.

• distal anastomotic sites have been treated successfully with balloon dilatation alone

• Stenting deployment compared to balloon angioplasty may further improve outcome.

Intermediate (1 month to 1 year)

• Recurrence of angina at about three months postoperatively is highly suggestive of a distal graft anastomotic lesion and in most cases, lead to evaluation for PCI

Late failure (>1 years after surgery)

• the most common cause of ischemia is the formation of new atherosclerotic plaques which contain– foam cells,

– cholesterol crystals,

– blood elements,

– necrotic debris as in native vessels.

• However, these plaque have less fibrocollagenous tissue and calcification, so they are softer, more friable, of larger size, and frequently associated with thrombus.

Recommendations for PCI With Prior CABG

Class I:Patients with early ischemia (usually within 30 days) after CABG.

(Level of evidence: B)

Class IIa:1. Patients with ischemia occurring 1 to 3 years post-operatively and

preserved LV function with discrete lesions in graft conduits. (Level of evidence: B)

2. Disabling angina secondary to new disease in a native coronary circulation. (If angina is not typical, the objective evidence of ischemia should be obtained). (Level of evidence: B)

3. Patients with diseased vein grafts > 3 years following CABG.(Level of evidence: B)

Recommendations for PCI With Prior CABG

Class III:

1. PCI to chronic total vein graft occlusions.

(Level of evidence: B)

2. Patients with multivessel disease, failure

of multiple SVGs, and impaired LV

function. (Level of evidence: B)

• The status of the LAD and its graft significantly influences the selection process.( because lack of survival benefit of repeat surgery to treat non-LAD ischemia.)

Intervention in degenerated saphenous vein grafts:

• The lesions that are bulky or associated with thrombus are considered to be high-risk.

• The complications include distal embolization, no-reflow, abrupt closure, and perforation.

• So different approaches were devised because there is much to lose from the standpoint of distal embolization causing non-Q MI and increasing long-term mortality.

• In the case of perforation of SVG, usually there is contained perforation rather than cardiac tamponade due to the extrapericardial course of the grafts.

• Prevention of distal embolisation

– Distal protection devices.

– Proximal protection devices.

SAFER Trial – Comparison of

PercuSurge to Routine Stenting in SVG’s

801 Patients Randomized

30 Day MACE

Reduced 42%

P<0.001

Baim et al. Circulation 2002; 105: 1285.

Routine PercuSurge

%

0

20

16.5%

9.6%

The 800 patient multicenter randomized SAFER trial demonstrated a 50% reduction in in-hospital adverse events with PercuSurge distal protection during SVG stenting, when compared to stenting without protection

PercuSurge System

Advantages

Captures smaller

particles and

“humoral” mediators

Disadvantages

Transient occlusion

Long “parking”

segment

Side branches

unprotected

Filter wire

.

In Filter wire-type devices, An emboli entrapment net is mounted on a 0.014" guidewire and expanded distally to the lesion.

Intervention is then performed over the guidewire.

Filters do not block distal blood flow when first deployed unlike occlusive devices.

Dislodged material is caught by the distal filter, which is then closed and retracted only at the end of the procedure.

Fire Trial: Randomized BSC/EPI

Filter vs. PercuSurge in SVGPCI650 patients in 65 sites

Conclusion: FW not inferior to GW

Stone et al. J Am Coll Cardiol 2003; 41: 43A

FW GW

TIMI 3 Flow 95.7% 97.7%

Device Success 95.5% 97.2%

Death 0.9% 0.9%

MI 9.0% 10.0%

QMI 0.9% 0.6%

30 day MACE 9.9% 11.6%

PROXIMAL OCCULUSION

DEVICES

These devices occlude flow into the

vessel using a balloon on the tip of

catheter

Two proximal occulusion catheters are in

use:

Proxis catheter

Kerberos embolic protection system

These have potential advantage of providing embolic protection even before the first wire crosses the lesion.

Proxis In Vessel

Benefits to Proximal Protection

Nothing crosses the lesion prior to protection

Protection of main vessel and side branches

Captures large and small particles

Can handle large embolic loads

• Is there a role for 2b3a inhibitors in SVG interventions ?

SVG PCI

Recommendation COR LOE

Embolic protection device use when technically feasible

I B

GP IIb/IIIa inhibitors III - No Benefit

B

PCI for chronic SVG occlusions III - Harm C

GNL 2011

No Reflow Pharmacological Therapy

Recommendation COR LOE

Administration of an intracoronary vasodilator (adenosine, calcium channel blocker, or nitroprusside) to treat PCI-related no-reflow that occurs during primary or elective PCI

IIa B

GNL 2011

• Do DES offer an advantage over BMS in SVG

• The data at present indicate that DESs in SVGs are safe; the occurrence of death or MI is equal or less than with BMSs, and there is no difference in stent thrombosis.

• Use of DES has been associated with a reduction in angiographic restenosis and TLR in patients undergoing SVG PCI.

• Choosing DESs over BMSs for the treatment of severe focal SVG stenoses must depend on the assurance of reliable dual antiplatelet therapy and be favoured in SVGs < 3.5 mm in diameter and in patients at high risk for restenosis (long lesions, diabetics).

CONCLUSION• SVG PCI is complicated by atheroembolic myocardial infarction and

high subsequent cardiac events due to restenosis and progressive vein graft disease.

• However, embolic protection strategies documented to be beneficial across the entire range of risk strata are markedly underutilized.

• Will physician education be sufficient to change this practice?

• Are DESs sufficiently effective in SVGs to warrant the increased cost associated with their use?

• Is one DES more effective than others?

• And finally, can disease progression in non target sites be retarded?

• Will the use of “plaque sealing” of moderate SVG lesions by DES implantation, which appeared promising in a pilot trial, be tested in the multicenter study required to corroborate these findings?

• In the future of bypass graft intervention, there are more questions than answers.

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