Recently, Prostate Artery Embolization (PAE) has been introduced worldwide as a procedure that can help resolve symptoms of Benign Prostate Hyperplasia (BPH).
It is a less invasive procedure then treatments currently in use.
This article details the PAE procedure for BPH.
What is BPH?
An enlarged prostate (BPH) is a condition known to affect more than fifty percent of men over 60 years of age.
While it is benign and rarely leads to prostate cancer, it can cause serious and uncomfortable urological symptoms.
If left untreated for long periods, incomplete emptying of the bladder can lead to serious kidney disorders.
Common symptoms of BPH are:
- Frequent urination or urgent feelings to urinate.
- Urinary hesitancy.
- Waking at night several times to urinate (nocturia).
- Difficulty in starting or stopping urination.
- Dribbling or leakage after urination.
- A weak urine stream.
BPH in most men can often be resolved using herbs, natural remedies, or prescription medications. But when symptoms are severe, a procedure called a Trans-Urethral-Prostatectomy (TURP) is recommended.
What is Prostate Artery Embolization?
An embolism is a result of a blockage, (embolus) inside a blood vessel. The embolus can be from several causes.
In most cases, an embolus is an unwanted spontaneous action in the body.
For example; an embolism in an artery leading to the heart can disrupt blood flow to the heart and result in damage to the heart due to a heart attack.
Embolization is the process of causing blockage in an artery. Most often, it is used to shrink a tumor by starving it of nutrient-rich blood.
A common use is to shrink benign uterine fibroid tumors in women. By cutting off the blood supply to the fibroid, it shrivels, shrinks and slowly dies. The body absorbs the tumor as it disintegrates.
Prostate artery embolization (PAE) is a relatively new procedure for the treatment of an enlarged prostate.
The treatment has been used for several years in Europe and was approved for use in the US by the FDA in June of 2017.
PAE is one potential alternative to surgical treatment for BPH, such as transurethral resection of the prostate (TURP). However, while it shows significant potential, it is a new procedure with few documented studies to date.
The procedure is being performed worldwide. However, due to its newness, there are no long-term, high-level studies that show evidence of its safety or efficacy.
The underlying theory for the PAE procedure is that reducing blood supply to the enlarged prostate will starve it of nutrients that are contributing to its growth.
This will, in turn, cause it to shrink and relieve symptoms caused by the swollen prostate.
How PAE is Performed
The procedure is performed by an interventional radiologist rather than a urologist. Before the procedure, patients are screened using state-of-the-art CT and MRI imaging.
This ensures that prostate and nearby arteries are unobstructed. It also rules out malignancy, anatomical variations, or other contraindications for the procedure.
- A PAE is generally performed in a hospital setting under light or local sedation. It usually does not need an overnight hospital stay. Post-procedure recovery is typically one to two days at home or less.
- To perform the procedure, the radiologist guides a small catheter from the patient′s upper thigh or groin. They then thread the catheter into an artery supplying the prostate.
- With the catheter in position, the radiologist injects a harmless dye to visualize the exact paths of blood flow.
- Once the exact blood flow is determined, small particles of foreign material are injected to block blood flow to the prostate. The success of the desired blockage is confirmed by continuous imaging.
- The particles or embolytic agents are conventional polyvinyl alcohol (PVA) particles. The size ranges from 50–500 micrometers.
Reports show that spherical agents with different properties have been used. But there is no current evidence that any specific size or type of embolytic agent has superiority.
This process is repeated with other vessels feeding the prostate that are to be blocked.
Partial blocking of the vessels leading to the prostate reduces blood flow to the organ and hopefully, causes it to shrink.
This helps reduce discomfort and symptoms related to BPH, including urinary and kidney problems.
Note that there is a cohort of patients for whom this procedure, even though performed successfully, does not achieve the desired result.
During the procedure, a Foley catheter (a hollow tube with a balloon at the end to hold it in place) may be inserted through the urethra to allow drainage. The catheter is usually removed the same day or the morning following the procedure.
Patients that are diagnosed with BPH typically go to a urologist for treatment. Most urologists are also surgeons and usually recommend a TURP procedure.
Natural health practitioners often recommend a holistic approach to rectify BPH symptoms by using over-the-counter nutrients and herbal remedies. In patients without acute symptoms, this approach may result in an acceptable solution.
In some cases, a TURP is counter-indicated based on the patient’s age or other conditions. BPH sometimes coexists with prostate cancer. Other conditions, especially advanced age, may rule out a surgical approach.
Currently, the BPH treatment cohort is typically younger patients with significant symptoms.
Usually, they have tried the various medications or holistic remedies available and failed to get sufficient improvement. Or they could not tolerate the medications side effects. Also, many patients rule out surgery because of its inherent risks or procedure side effects.
The success of many treatment options for BPH is dependent on prostate gland size.
A PAE is technically easier than a TURP with large, vascular prostates. There is no firm evidence that confirms better outcomes with larger prostates. But a few studies have noted improved symptom relief for men with larger prostates.
In prior years, complete surgical removal of the prostate was recommended.
However, this is major surgery with its associated surgical risks and severe long-term side effects, especially on a man′s quality of life. Today′s techniques have generally rendered this recommendation obsolete.
Patients must be advised of all available treatment options before making this critical decision. Unfortunately, some urologists are reluctant to recommend a radiologist for a procedure they consider in the realm of urology.
Rather than viewing interventional radiologists as competitors, urologists need to recognize them as partners in the overall care of the patient.
Unfortunately, many patients have little knowledge of the technical aspects of the various procedures.
Such patients may simply follow the recommendations of a urologist. The urologist may be reluctant to recommend anything other than a procedure he or she is intimately familiar with. A second opinion might offer more options.
Far too often, a man in his late 80′s or early 90′s is subjected to a TURP procedure for acute urinary retention or other serious symptoms. Persistent urinary retention resulting from BPH can cause serious kidney issues.
In elderly patients, the risks of surgery need to be a primary consideration. Urinary retention can be relieved by teaching the patient how to perform a simple at-home catheterization procedure.
Comparison of PAE vs. TURP for Treatment of BPH
For several years, a TURP has been the standard of care of treatment for men with BPH. However, within the last few years, PAE has been increasingly introduced for treating symptoms of BPH.
This has not been without controversy. While PAE seems to offer promising outcomes, there are few published high-quality trials on its safety or efficacy.
While both procedures have similar side effects, PAE has virtually no blood loss and requires less indwelling time of a bladder catheter and no hospital stay.
Both procedures convey a risk of acute urinary retention requiring post-procedure, long-term catheterization but the rate of occurrence was less than 2 percent in most studies. PAE seems to be better tolerated than TURP in this area.
Symptoms play a significant role in patient selection for PAE. The most significant symptoms reported by patients are:
- Nighttime urination (nocturia).
- Urinary hesitancy.
- Incomplete urination or urinary retention.
These three symptoms have the most impact on a patients quality-of-life score. Initial evidence for PAE suggests that it has a greater effect on these symptoms than a surgical TURP. Patients with acute urinary retention may fare better with PAE.
Adverse events are similar for both treatments, but patients undergoing PAE reported more post-procedure pain, as well as more complications specific to vascular interventions.
PAE patients seemed to have fewer problems with post-procedure erectile dysfunction.
While most side effects were limited to a small percentage of patients, some of them can be quite serious.
Studies have reported a hematoma at or near the catheter insertion site, a post-procedure fever, a case of new-onset erectile dysfunction, and a loss of blood supply to a portion of the bladder wall.
This latter condition was serious and required trans-urethral surgery to remove necrotic bladder tissue.
Patients undergoing PAE had significantly less post-procedure erectile dysfunction than those undergoing a TURP.
In the literature, TURP causes retrograde ejaculation in almost 100 percent of patients, while there was little evidence of it for the PAE procedure.
Retrograde ejaculation is where the man′s ejaculate flows back into the bladder rather than exit through the penis. While this is bothersome for some men, it has little effect on functionality or sensation. It does, however, result in the inability to sire children.
Both the PAE and TURP procedures are generally safe.
The complication rate of each procedure is generally not clinically significant.
Improvement in symptoms is realized in more than 80 percent of patients. However, both procedures suggest that up to 10 percent of patients will have some symptom recurrence within 5 years.
The PAE procedure seems to produce a large reduction in prostate volume three months post-procedure. This may be due to atrophy of nutrient-starved prostate gland tissue. Men with larger prostates may experience more of this effect.
While imaging is a necessary part of the PAE procedure, radiation doses detailed in the literature are minimal, and there have been no significant clinical notations or implications.
Potential Complications of PAE
PAE is a procedure that affects blood flow in an organ, the prostate. Thus, there is always the potential for an ancillary over blockage to occur. This could completely cut off blood supply to the prostate.
Particles introduced to the prostate vessels might migrate to other nearby structures, such as the bladder or rectum. This could result in an unplanned blockage that may have serious consequences. This is called non-target embolization.
While the number of cases in the literature is small, non-target embolization affecting the rectum, bladder, and penis has been reported.
However, while non-target embolization is serious, most cases were self-limiting or resolved with conservative management.
Semi-major complications of PAE include :
- the inability to urinate freely after the procedure.
- acute urinary retention.
Both complications may require more days of using an indwelling catheter. This could increase the risk of post-procedure urinary tract infection.
Such complications occurred in between 10 and 20 percent of the patients in some studies.
Other common minor complications reported were blood in the semen and minor rectal bleeding. Each was reported in less than 10 percent of the patients.
The use of PAE to replace the standard TURP for the treatment of BPH is somewhat controversial.
Treatment of urological issues has traditionally been the domain of urologists. However, the PAE procedure requires a different skill set. One that falls within the range of interventional radiologists.
In the real world, the competition between these two groups can result in contradictory information reaching patients. This, of course, is dependent on a physician′s discipline.
Adding to this controversy is a lack of substantial evidence supporting superior efficacy and safety of the PAE procedure over conventional TURP surgery.
Many of the studies reviewed did not have a sufficient number of patients to determine if either procedure was superior conclusively. Also, facilities performing the procedure were often very selective about choosing patients.
While there is no consensus for screening patients for the procedure, there is a tendency for PAE to be offered to only to patients that are deemed poor candidates for surgery.
Factors to consider
Elderly patients are often excluded, although many of them may benefit from PAE. Also, patients using blood thinners or who have conditions affecting blood circulation are often excluded.
PAE can be a challenging procedure to perform due to individual anatomy variations. Thus some centers rule outpatients with arterial kinks or twists that may cause complications. Abnormal anatomy often results in longer screening times, higher radiation doses, and increased risk of procedure failure.
The net result of the combined selection process may be that that the efficacy and safety of the procedure can appear enhanced when reported outcomes are published.
Often, patients who receive the procedure are less likely to have co-morbidities. Improvements of PAE over other standard treatment can be artificially inflated.
Results of the latest published information indicate that similar improvement in symptoms is achieved with PAE and TURP. However, the TURP procedure offered a clear advantage over a PAE regarding improved urination parameters and reduction in bladder outlet obstruction.
The PAE procedure offers minimally invasive therapy for BPH. However, it can also cause non-target embolization to nearby vessels, causing incidental damage to other structures in the body. To date, PAE has little conclusive long-term studies regarding its efficacy and safety.
There are few reports of PAE associated complications. Typically sites performing and writing on the procedure are those already performing it. Thus, there may be some inherent bias in their results.
PAE has been reported to have a higher complication rate than a TURP. While the scope of adverse events after PAE seems to be less when compared to TURP, this may be an underestimation due to inherent bias or lack of long-term data on the procedure.
Preserving erectile function
Preservation of erectile and ejaculatory function is a primary consideration for any procedure.
To date, some literature has indicated that one or both of these functions were compromised in a small number of patients after a PAE.
Again this could be due to an inherent reporting bias or a lack of quality information. Since current data only represents short-term outcome, this may change as long-term data becomes available.
PAE is a complex procedure involving highly variable anatomy. In the human body, blood vessels that become partially blocked often result in the body growing new vessels around them to serve as backup routes for blood flow. This process is quite normal and is called anastomosis.
Since the PAE procedure, by definition, is a process by which blood vessels are deliberately blocked, anastomosis can be a natural product of the procedure.
A high incidence can occur in some patients. This, of course, can negate initial benefits of the procedure, and may not show up for years.
There is some evidence that, over time, the short-term benefits of a PAE could be overcome by the normal process of an anastomosis. This could result in a multitude of vessels restoring blood flow to the area of the prostate blocked by the procedure.
Prostate artery embolization (PAE) appears to be a valuable alternative to TURP for the treatment of BPH.
It might be considered for patients that have minimal symptoms and no serious complications. For patients with severe symptoms of BPH, TURP appears to be more effective than PAE.
Following this more large-scale controlled studies with long follow-up periods must be evaluated before PAE is considered as a routine treatment.
- The PAE procedure seems to have minimal side effects.
- Virtually no surgical risks.
- Allows for same-day hospital discharge.
- Rapid return to normal activity with few lingering effects.
While there will always be a degree of competition between medical professionals treating the same condition, urologists and interventional radiologists need to come together and work collaboratively to access the safety and efficacy of the PAE procedure with additional studies.
All practitioners need to provide the best available evidence supporting each potential treatment option. This information is necessary to enable a patient to choose wisely.
It is also essential that interventional radiologists who perform this procedure have in-depth knowledge and understanding of the male pelvic arterial anatomy. They should also have a solid familiarity with embolization techniques.
PAE appears to be a valid procedure for the treatment of BPH. However, further collaborative trials of the PAE procedure compared to the current standard TURP procedure, with longer-term data would be extremely beneficial.