Microwave treatments for enlarged prostate cause blood pressure
18 April 2008
Many men who receive microwave therapy for enlarged prostates
experience significant surges in blood pressure that could raise their
risk of a heart attack or stroke, according to new research findings
published recently in Mayo Clinic Proceedings.
The Mayo Clinic-led study of 185 consecutive patients who received
transurethral microwave therapy at four medical centres found that 42%
experienced systolic blood pressure surges of more than 30 mm Hg, while
5% had surges of more than 70mm Hg.
"Men who are candidates for this minimally invasive microwave therapy
tend also to be at higher risk for cardiac events," says Lance Mynderse,
MD, the Mayo Clinic urologist who authored the study. "Blood pressure
surges of the magnitude identified in this study are troubling side
effects of treatment that need to be monitored and managed."
Benign prostatic hyperplasia (BPH), or an enlarged prostate gland, is
a condition affecting half of men over age 50 and 80% of those over 70.
Symptoms include difficult urination, sudden urges to urinate and
inability to empty the bladder. BPH often is treated with medication and
in severe cases open surgery may be necessary, but since 1997
transurethral microwave therapy has been a less-invasive option.
Transurethral microwave therapy involves using a catheter to place a
microwave device within the prostate, which is then heated to destroy
excess tissue. Approximately 70,000 such procedures are performed each
year, usually in an office setting and typically involving patients from
50 to 85 years old.
"This patient population is at high risk of cardiovascular disease,"
explains Benjamin Larson, a medical student at Cleveland Clinic who is
the lead author of the Mayo Clinic Proceedings paper. "Anecdotal reports
of adverse blood pressure events during and after transurethral
microwave therapy, and our own experience, led us to look back at the
records to identify potential problems among these patients whose blood
pressure had been monitored."
The authors say the study findings should not necessarily deter
physicians and their patients from using one of the six FDA-approved
devices for transurethral microwave therapy, but they should take
reasonable precautions given the strong possibility of blood pressure
"Blood pressure monitoring should be a standard part of the
procedure. Blood pressure readings should be taken throughout the
procedure, multiple times. Unfortunately, that has not always been the
practice for this office-based therapy," Dr Mynderse explains.
"Monitoring will enable physicians to identify the problem and adjust
treatment. Patients also should be encouraged to continue their
anti-hypertensive medications, particularly beta blockers, as they
prepare for the procedure."