michigan hypertension core curriculum - State of Michigan

stenosis severity. Patients with non-obstructive FMD (no TLG, no stenosis by IVUS) should be treated
conservatively.
In patients with ARAS, stenting is recommended to eliminate elastic recoil, minimize dissection,
and maximize lumen enlargement. 49-51 Most studies report procedural success rates of 95-100 %,
residual diameter stenosis < 10 %, restenosis rates of 10-15 % within 1 year, and major complications
in < 2 % (20, 50-53). 20,21,50-52
There are a number of important technical and procedural considerations (Table 7), to avoid
renal artery injury, kidney injury, and atheroembolization. Selective renal arteriography should
be guided by abdominal aortography; the catheter-in-catheter or no-touch techniques should be
utilized to minimize contact with the aortic wall and injury to the renal ostium during guiding catheter
engagement 53 (Figure 8). The nephrotoxic effects of radiographic contrast are minimized by maintaining
adequate hydration, limiting contrast volume, and using digital subtraction angiography. Renal
embolization during revascularization appears to be fairly common 54,55 and one small randomized study
suggested potential benefit of a combination of distal embolic protection and intravenous abciximab. 56
Since 14 % of patients have early renal bifurcations (Figure 3), complete renal “protection” may not
be possible. Most devices are not designed for the renal circulation and may add procedural time and
complexity, so the long-term value of renal embolic protection has not been established.
Is mild improvement in blood pressure clinically relevant? Among conventional risk factors,
hypertension has the strongest association with stroke, kidney disease, and congestive heart failure; is
the most important modifiable risk factor in reducing cardiovascular morbidity, mortality, and disability;
is easy to recognize; and has been proven to increase survival when treated in accordance with simple
guidelines. 57 Even small decrements in systolic (10 mmHg) and diastolic (3-6 mmHg) BP are associated
with 30-40 % reduction in risk. 58,59 Therefore, therapies which offer even small absolute improvements
in BP are worthy of consideration, because they may translate into large clinical benefits and risk
reduction.
ARAS and hypertension outcomes. There are 3 published randomized trials comparing angioplasty
to medical therapy in a total of 210 hypertensive patients with ARAS ! 60-62 In one trial, angioplasty
produced significant reduction in BP and medication requirements at three months, whereas medical
therapy did not. 60 Since, 44% of medical patients crossed-over to angioplasty at 3 months, the
intention-to-treat analysis revealed no difference in BP or medication requirements at 1-year. In another
112 Hypertension Core Curriculum