Blood pressure responses after carotid surgery: relationship to postoperative baroreceptor sensitivity.
OBJECTIVE
Among hypertensive patients after carotid surgery, a group of patients with increased baroreflex sensitivity was identified. In the other group of hypertensive patients, blood pressure and reflex sensitivity were unchanged postoperatively. We hypothesized that a partial readjustment of baroreceptor sensitivity would produce more stable blood pressure profiles.


METHODS
In order to test this hypothesis, a prospective, long-term follow-up study was designed. Blood pressure was monitored in 18 hypertensive and 6 normotensive patients during 6 months using a self-measurement technique. In addition, continuous 24-hour blood pressure monitoring was performed 6 months after surgery. The mean values and the ranges (amplitudes) of systolic and diastolic blood pressure were calculated as indicators for the stability of the circulatory system.


RESULTS
Hypertensive patients with unchanged postoperative baroreceptor sensitivity showed significantly more pronounced instabilities of their blood pressure profiles (amplitudes of systolic and diastolic blood pressure p < 0.05 to p < 0.001). A relationship between baroreceptor function and antihypertensive therapy could also be demonstrated, with adequate therapy being much more difficult in patients with reduced or unchanged baroreceptor sensitivity.


CONCLUSIONS
In contrast to vascular surgery on the aorta or in the region of the lower limbs, carotid surgery is frequently associated with blood pressure changes, demonstrating the essential role of the baroreceptors in the carotid sinus for the regulation of postoperative blood pressure. Since it seems to be the variability of blood pressure, and not the blood pressure level alone, that is critical, close blood pressure monitoring--allowing for an assessment of blood pressure variability--appears to be of particular importance in such patients.
From the Department of Angiology, Vienna, Austria.
Mirko
M
Hirschl
From Hanuschkrankenhaus, the Institute of Environmental Hygiene, Vienna, Austria.
Michael
M
Kundi
From the Departments of Emergency Medicine, Vienna, Austria.
Michael M
MM
Hirschl
From the Clinical Pharmacology, New General Hospital, Vienna, Austria.
Bernhard
B
Liebisch
From the Clinical Pharmacology, New General Hospital, Vienna, Austria.
Dieter
D
Magometschnigg
D000368:Aged; D000704:Analysis of Variance; D000804:Angiotensin II; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D001795:Blood Pressure Determination; D016894:Endarterectomy, Carotid / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin; D011184:Postoperative Period; D011311:Pressoreceptors / Q000187:drug effects / Q000502:physiology*; D011446:Prospective Studies; D014636:Valsalva Maneuver / Q000502:physiology
D000804:Angiotensin II; D005996:Nitroglycerin