Is Ambulatory Carotid Stenting Safe? Too Early to Say
To the Editor:
We read with interest the recent article by Al-Mubarak et al.1 We agree that ambulatory (same-day discharge) carotid stenting is a feasible option and note the admirable absence of neurological events and deaths in this group.
Same-day discharge has important cost implications. Carotid artery stenting has already been shown to be as safe and efficacious as carotid endarterectomy2 and could prove a more attractive alternative if also more cost-effective. The use of vascular closure and neuroprotection devices does not add to the cost of the ambulatory group, as suggested in the editorial comment,3 as these devices, if employed, would be used in all carotid stent patients regardless of future discharge plans. Their cost, therefore, should not be used in a cost-analysis comparison between ambulatory and hospitalized carotid artery stenting patients.
We would, however, like to add a note of caution. Hemodynamic instability, particularly hypotension, may be a consequence of carotid artery stenting.4 It may be that this is a benign entity, but we feel that further evaluation of the timing of these disturbances and any consequent neurological complications is required before same-day discharge following carotid artery stenting can be confidently recommended.
- ↵Al-Mubarak N, Roubin GS, Vitek JJ, New G, Iyer SS. Procedural safety and short-term outcome of ambulatory carotid stenting. Stroke. 2001; 32: 2305–2308.
- ↵Pelz D. Procedural safety and short-term outcome of ambulatory carotid stenting. Stroke. 2001; 32: 2308–2309.Editorial comment.
- ↵Qureshi AI, Luft AR, Sharma M, Janardhan V, Lopes DK, Khan J, Guterman LR, Hopkins LN. Frequency and determinants of postprocedural hemodynamic instability after carotid angioplasty and stenting. Stroke. 1999; 30: 2086–2093.
We appreciate the interest of McKevitt and Cleveland. We agree that hemodynamic instabilities were of particular concern in undertaking the ambulatory approach for carotid artery stenting (CAS). The most important hemodynamic instability is sustained hypotension that occurs in the immediate postprocedural period and may last up to 24 hours.1–3⇓⇓ While “transient hypotension” and brady-arrhythmia are relatively common during balloon inflation, “sustained hypotension” occurred in 10% of the patients following CAS in our early experience.1 In our recent experience, particularly since the application of vascular closure devices and early ambulation following the procedure, this phenomenon has become very rare.
Sustained hypotension can be explained on the basis of the carotid sinus reflex arc. The baroreceptor nerve terminals located at the outer muscle layer of the carotid sinus respond to stretch and deformation of the arterial wall by transmitting impulses that inhibit the vasoconstrictor regions in the medulla oblongata, resulting in vasodilatation and hypotension. Bradycardia resulting from stimulation of the vagal regions contributes to the development of hypotension. The self-expanding stent through increased pressure on the carotid sinus wall can lead to inappropriate activation of the baroreceptors. Plaque disruption caused by balloon predilation may also enhance the pressure transmission to the carotid sinus baroreceptor. As the stent conforms to the arterial wall, the baroreceptors adapt to the sustained stimulation, gradually terminating the hypotensive response. We believe that early patient ambulation after the procedure helps counteract this hypotensive effect and may explain the rare occurrence of sustained hypotension in our recent experience. Therefore, the ambulatory approach by virtue of the early ambulation results in a low incidence of hypotension following CAS.
Although some investigators have reported adverse clinical events,2,3⇓ in our large experience these hemodynamic instabilities typically resolved without complications. Careful and constant hemodynamic surveillance of all patients in the first few hours following the procedure remains crucial for early recognition and management of hypotension, hence preventing adverse clinical sequelae. If sustained hypotension develops, the patient should be hospitalized and other possible etiologies such as bleeding, volume depletion, and cardiac pathologies must be considered and carefully excluded.
- ↵Al-Mubarak N, Liu MW, Gomez CR, Vitek JJ, Iyer SS, Roubin GS. Incidence and outcome of prolonged hypotension following carotid stenting. J Am Coll Cardiol. 1999; 1130–1145.
- ↵Dangas G, Laird JR Jr Satler LF, Mehran R, Mintz GS, Larrain G, Lansky AJ, Gruberg L, Parsons EM, Laureno R, Monsein LH, Leon MB. Postprocedural hypotension after carotid artery stent placement: predictors and short- and long-term clinical outcome. Radiology. 2000; 215: 677–683.