BBI Contributing Writer

SAN FRANCISCO, California – Several unique devices for use in obstetrics and gynecology were discussed at the 48th annual clinical meeting of the American College of Obstetricians and Gynecologists (ACOG; Washington) meeting held here in the latter part of May.

With serendipitous timing, Mallinckrodt (St. Louis, Missouri) was cleared by the FDA for marketing its OxiFirst Fetal Oxygen Monitoring System in the U.S. just days prior to the ACOG gathering. Until now, there has been no reliable way to directly measure the oxygen saturation of a fetus during labor. Traditionally, monitoring the fetal heart rate and uterine contractions has assessed the status of the fetus. However, in about 30% to 40% of all births, a non-reassuring heart rate pattern occurs on the electronic fetal heart rate monitor. This could indicate a dangerous lack of oxygen to the baby or something as innocuous as the baby falling asleep. The fetal heart rate monitor cannot distinguish between the two. Based on Nellcor's pulse oximetry technology, OxiFirst provides continuous, real-time, and objective measurement of fetal oxygen status during labor. Improved fetal assessment can help the obstetric staff to decide whether labor can progress safely through these non-reassuring fetal heart rate patterns, or if an intervention such as a C-section is needed.

Hugh Miller, MD, clinical associate professor at the University of Arizona (Tucson, Arizona), is a clinical investigator for OxiFirst and has used the sensor in more than 150 births. He said he believes that it is possible to reduce the number of C-sections required solely for non-reassuring tracings by 50%. In the randomized clinical trial that he participated in, when the OxiFirst sensor was used as recommended along with the fetal heart rate monitor, he was able to accurately identify babies with problems 100% of the time. Normally when using fetal heart rate alone, there is a false positive rate of 75%. In other words, when fetal heart rate indicates there is a problem, 75% of the time the baby is just fine. It can be anticipated that with increased use of the OxiFirst sensor, there will be a decrease in Caesarian sections. Table 3 shows the market potential for fetal oxygen monitoring sensors.

Table 3 Market Potential for Fetal Oxygen Monitoring Sensors
Annual births in U.S. 4 million
Annual births in developed countries 5 million
Total births 9 million
Births with non-reassuring heart rate pattern (35% of total) 3.15 million
Multiplied by $150 (cost of sensor) $472.5 million
Source: Mallinckrodt and The BBI Newsletter

Point-of-care testing for osteoporosis

Osteoporosis is a thinning of the bones that affects an estimated 10 million Americans, 80% of them women. Bones are constantly being broken down and then reformed, but when the breakdown process exceeds the building process, overall bone loss may occur. Most women rarely know they have osteoporosis until they break a bone.

Ostex International (Seattle, Washington) introduced the Osteomark NTx, a point-of-care device for measuring bone resorption, or bone breakdown. Currently, the standard test for osteoporosis is done by X-ray and measures bone mineral density (BMD), or bone mass. The Osteomark NTx measures a molecule that is released into the bloodstream during bone resorption. The test can be performed in five minutes in a doctor's office on the patient's urine. If the molecule is present in higher-than-normal amounts, then it can be assumed that osteoporosis may be occurring. The Osteomark NTx test is designed to be used in conjunction with BMD to assess the need for antiresorptive therapy, determine the probability for a decrease in bone mass for postmenopausal women who are not taking hormone replacement therapy, and monitor the patient's response to therapy. The test kit will be sold only to physicians once CLIA waiver is received (expected in the near term). The kit will be sold for approximately $25 and private payers will reimburse from $14 to $114. The Osteomark Ntx can be done three months after initiation of therapy, helping to determine if the patient's therapy is working; compared to a one-to-two-year wait for a BMD test. The Osteomark NTx test should revolutionize the monitoring of patients with osteoporosis.

Uterine artery embolization

About one-third of the 600,000 hysterectomies performed in the U.S. annually are due to fibroids, according to the National Center for Health Statistics (see Table 4). The search for less-invasive methods to remove fibroids has been under way for several years due to both patient and payer demand. Removing just the fibroid (a myomectomy) may produce similar short-term outcomes, but recurrence is always a concern. Uterine artery embolization (UAE) is an interventional radiology technique that temporarily cuts off blood flow to the uterus, causing any fibroids to die and then shrink and allowing for a non-surgical alternative to hysterectomy or myomectomy. The theory is that the uterus is a highly vascular organ and reperfuses itself shortly after the ischemic attack, but that fibroids cannot reperfuse, so they die.

Table 4 Potential Candidates for UAE
U.S. hysterectomies due to fibroids 200,000
U.S. myomectomies 150,000
25% of U.S. patients being treated with hormones for fibroids 250,000
Rest of world patients 500,000
Total annual potential patients 1.2 million
Source: National Center for Health Statistics

The reported success rate of uterine artery embolization is greater than 85%, with symptoms resolved after 24 hours. In addition, many patients have gone on to achieve successful pregnancies after UAE. The major roadblock to broad-based implementation of UAE is that catheter-based interventions are performed by an interventional radiologist. Gynecologists, the gatekeeper for these patients, do not perform interventional procedures, and so are faced with the dilemma of referring the patients to a radiologist and suffering the economic consequences or of selecting another therapy. As a result, only 6,000 UAEs have been performed worldwide in the five years since UAE was first developed, whereas hundreds of thousands of surgeries have been performed each year for uterine fibroids.

In a poster session at the annual clinical meeting, HysterRx (San Juan Capistrano, California), a start-up company, described a new UAE technique designed for gynecologists. This new method enables gynecologists to use a simple, ultrasound image-guided, transvaginal approach to occlude the uterine artery with a proprietary set of minimally invasive tools. Should this new method provide the same results as the interventional procedure – and theoretically it should – this may be the key to providing a non-surgical solution for the hundreds of thousands of patients currently undergoing hysterectomies or myomectomies.

Painless paracervical blocks, other procedures

Milestone Scientific (Livingston, New Jersey) received clearance from the FDA just after the ACOG meeting to market its product, the Wand, for medical uses. The Wand is a computer-controlled injection system that delivers precision-metered local anesthetic, resulting in virtually painless injections. It has been used in dentistry for the past two years. Several gynecologists have tried the Wand for paracervical blocks – the delivery of a local anesthetic agent into the cervix, allowing for manipulation of or access through the cervix without the associated pain. The cervix often is anesthetized for procedures such as LEEPs, colposcopic biopsies, and some endometrial samplings. Other procedures that may provide patients a more comfortable experience by using a painless injection include vulvar biopsies, circumcisions, minor excisions such as condylomas, as well as therapeutic abortions (see Table 5).

Table 5-Potential Procedures Where the Wand Could be Used
LEEPs worldwide 2.0 million
U.S. abortions 1.5 million
U.S. circumcisions 1.2 million
Endometrial sampling blocks 3.0 million
Colposcopic biopsies 3.0 million
Minor excisions (condyloma, etc.) 2.0 million
Total annual procedures 12.7 million
Source: The BBI Newsletter