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 centers found that 42
percent experienced systolic blood pressure surges of more than 30 mm Hg,
while 5 percent had surges of more than 70 mm Hg.
"Men who are candidates for this minimally invasive microwave therapy
tend also to be at higher risk for cardiac events," says Lance Mynderse,
M.D., 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 percent 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
surges. "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."
Besides Larson and Dr. Mynderse, other authors of the paper include
Thayne Larson, M.D.; Virend Somers, M.D., Ph.D.; Michael Jaff, D.O. and
William Evans, D.O.
A peer-review journal, Mayo Clinic Proceedings publishes original
articles, reviews and editorials dealing with clinical and laboratory
medicine, clinical research, basic science research and clinical
epidemiology. Mayo Clinic Proceedings is published monthly by Mayo
Foundation for Medical Education and Research as part of its commitment to
the medical education of physicians. The journal has been published for
more than 80 years and has a circulation of 130,000 nationally and
internationally. Articles are available online at
mayoclinicproceedings.
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