RENAL AND MESENTERIC ARTERY STENTS Are There Standard Velocity Criteria for Restenosis?

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1 RENAL AND MESENTERIC ARTERY STENTS Are There Standard Velocity Criteria for Restenosis? R. Eugene Zierler, M.D. The D. E. Strandness, Jr. Vascular Laboratory University of Washington Medical Center Division of Vascular Surgery University of Washington, School of Medicine

2 DISCLOSURE INFORMATION R. Eugene Zierler, M.D. No relevant financial or commercial relationships to declare

3 RENAL AND MESENTERIC ARTERY STENTS Duplex Scanning Topics for Discussion Criteria for native renal and mesenteric arteries Experience with follow-up of renal and mesenteric stents Criteria for stented renal and mesenteric arteries Clinical protocols for duplex follow-up

4 RENAL AND MESENTERIC ARTERY STENTS Duplex Scanning of the Renal and Mesenteric Arteries General Principles Same as other arterial duplex examinations Stenoses are identified by a localized high velocity jet with post-stenotic turbulence Classify lesions in ranges of stenosis severity Atherosclerotic lesions typically at or near the origins of the renal and mesenteric arteries High-grade (pressure/flow-reducing) lesions necessary to produce clinically significant renal and mesenteric ischemia

5 RENAL ARTERIES Duplex Criteria for Native Renal Arteries Normal Low Resistance Renal Artery Flow Patterns

6 RENAL ARTERIES Duplex Criteria for Native Renal Arteries Renal Artery Diameter Reduction Normal Renal Artery PSV (cm/s) Renal Aortic Ratio (RAR) <180 < 3.5 <60% 180 < % ( 80%) 200 (EDV 150) 3.5 Occlusion No signal No signal

7 RENAL ARTERIES Duplex Criteria for Native Renal Arteries Validation for 60% Stenosis Duplex vs. Arteriography Hansen J Vasc Surg 1990 Hoffman Kid Int 1991 Olin Ann Int Med 1995 Nchimi J Eur Rad 2003 Li J Vasc Surg 2008 ( 50% stenosis) Sensitivity Specificity Accuracy 88% 99% 91% 92% 62% 81% 98% 98% 97% 91% 97% 96% 90% 90% 90%

8 MESENTERIC ARTERIES Duplex Criteria for Native Mesenteric Arteries Celiac Celiac Fasting SMA Transverse Celiac and SMA IMA Longitudinal

9 MESENTERIC ARTERIES Duplex Criteria for Native Mesenteric Arteries % Stenosis Peak Systolic Velocity End Diastolic Velocity Sensitivity Specificity Bowersox 1991 SMA SMA Moneta 1993 SMA Celiac Zwolak 1998 SMA SMA Celiac Celiac AbuRahma 2012 SMA SMA Celiac Celiac 50% 50% 70% 70% 50% 50% 50% 50% 50% 70% 50% 70% 300 cm/s 275 cm/s 200 cm/s 300 cm/s 200 cm/s 295 cm/s 400 cm/s 240 cm/s 320 cm/s 45 cm/s 45 cm/s 55 cm/s 63% 100% 92% 87% 60% 90% 93% 93% 87% 72% 88% 80% 100% 92% 96% 80% 100% 91% 94% 100% 89% 93% 83% 89% AbuRahma 2011 IMA 50% 250 cm/s 90% 96%

10 RENAL AND MESENTERIC ARTERY STENTS Threshold velocity criteria have been validated for native renal and mesenteric arteries Velocities in widely patent stents can be higher than those in widely patent native arteries (carotid, renal, mesenteric) Stent reduces arterial compliance (increased stiffness) Energy normally applied to dilate the artery results in higher peak flow velocities Specific duplex criteria are needed for stented renal and mesenteric arteries to avoid overestimation of stenosis severity Primary patency rates are relatively low and restenosis rates are relatively high in stented renal and mesenteric arteries

11 RENAL ARTERY STENTS Renal arteries Most studies report restenosis rates Author Year # Cases % With Restenosis at Follow-Up (Months)* Henry Sivamurthy Rocha-Singh Corriere Davies Thalhammer Laird Jaff Simone *Intervention for atherosclerotic renal artery stenosis

12 MESENTERIC ARTERY STENTS Superior mesenteric and celiac arteries Most studies report patency Author Year Primary Patency (Years) Assisted-Primary Patency (Years) Secondary Patency (Years) # Patients/ Vessels Mean or Median Follow-up Sarac % % % /87 - Oderich % 41% % 88% 83/ months AbuRahma 2013* 69% 39% 19% 80% 54% 34% / Months Bulut % - 45% 90% - 70% 98% - 94% 141/ months *Late 70% in-stent stenosis rate was 51% at mean follow-up of 31 months Assisted primary and secondary patency rates suggest that periodic follow-up and reintervention improve overall outcomes

13 MESENTERIC ARTERY STENTS Duplex Follow-up of SMA Stents 35 patients with mesenteric ischemia >70% SMA stenosis or occlusion in 32 pre-stent Mean pre-stent SMA PSV 450 cm/s <30% post-stent stenosis by arteriography in all patients Mean early post-stent SMA PSV 336 cm/s (threshold for 70% native SMA stenosis is 275 cm/s) SMA PSV decreased following stenting but remained high relative to native SMA PSV Duplex criteria for native SMA stenosis overestimate stenosis in after stenting Mitchell et al. J Vasc Surg 2009;50:335

14 MESENTERIC ARTERY STENTS Duplex Follow-up of SMA Stents 27 patients having primary mesenteric stents Mean pre-stent arteriographic stenosis 79% Mean pre-stent SMA PSV 464 cm/s <20% post-stent stenosis by arteriography in all patients Mean post-stent SMA PSV: 335 cm/s at 1.5 months 389 cm/s at 5.1 months 8 patients required reintervention for in-stent restenosis, with a mean SMA PSV of 505 cm/s (vs. 341 cm/s in patients with no reintervention) Mean SMA PSV was 398 cm/s post-reintervention SMA PSV remains higher than the native 275 cm/s threshold after successful SMA stenting Baker et al. J Vasc Surg 2012;56:1364

15 RENAL AND MESENTERIC ARTERY STENTS Are there standard criteria for in-stent restenosis? NO Not yet, but here is what we know

16 STENTED RENAL ARTERIES Duplex Criteria for Stented Renal Arteries (In-stent Stenosis) PSV (cm/s) RAR Sensitivity Specificity Accuracy Olin % Native >200 >3.5 98% 98% 97% Mohabbat % Stented Chi % Stented Fleming % Stented Del Conde % Stented > > % 83% 83% 94% 100% 89% 88% 86% % 88% % 95% 83% PPV 94% PPV 96% Threshold PSV and RAR values are higher for renal artery in-stent stenosis vs. native arteries

17 STENTED RENAL ARTERIES Duplex Criteria for Renal Arteries Conclusions Renal Artery 60% Stenosis PSV (cm/s) RAR Native Renal Stented Renal Note: Threshold for 60% in-stent stenosis is my best estimate based on a relatively small number of studies (may be revised based on new data)

18 STENTED MESENTERIC ARTERIES Duplex Criteria for Stented Mesenteric Arteries (In-stent Stenosis) Moneta 1995 Native SMA 70% Native Celiac 70% AbuRahma 2012 SMA 70% Celiac 70% Soult 2016 SMA 70% Celiac 70% PSV (cm/s) Sensitivity Specificity Accuracy 92% 87% 100% 88% 83% 100% 96% 80% 95% 92% 83% 57% 96% 82% 97% 90% - - Threshold PSV values are higher for 70% SMA and celiac artery in-stent stenosis vs. native arteries

19 STENTED MESENTERIC ARTERIES Duplex Criteria for Mesenteric Arteries Conclusion Celiac Artery 70% Stenosis PSV (cm/s) Superior Mesenteric Artery 70% Stenosis PSV (cm/s) Native Celiac 200 Native SMA 275 Stented Celiac 325 Stented SMA 430 Notes: Thresholds for 70% in-stent stenosis are my best estimate based on a small number of studies (may be revised based on new data) Patients having reintervention for SMA in-stent stenosis have PSVs around 500 cm/s

20 STENTED MESENTERIC AND RENAL ARTERIES Protocols for Follow-up - Summary Restenosis rates suggest that periodic follow-up and reintervention will improve long-term outcomes Mesenteric and Renal Artery Stents* Clinical follow-up and baseline duplex within 1 month of the procedure Clinical follow-up and duplex at 6 months, 12 months, and then annually thereafter Consider additional evaluation and imaging for return of preintervention symptoms/signs or severe in-stent stenosis on duplex Note: Although there is no high quality evidence to support frequent duplex follow-up, the costs and risks are considered to be low, and early detection of restenosis may provide better long-term outcomes *Adapted from the SVS Practice Guidelines J Vasc Surg in press

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