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